Technical Field The present invention relates to low cost motors and their methods of manufacture, and more particularly, to new and improved twin bobbin two pole and four pole motors and their methods of manufacture.

In conventional C-frame two pole motor constructions, a first stack of magnetically conductive laminations is provided with aligned circular-shaped rotor openings at one end and aligned U-shaped openings at a second end. A separate elongated second stack of laminations is mounted to the first stack of laminations across the aligned U-shaped openings of the first stack of laminations after a single electrically conductive coil is positioned over the separate elongated second stack of laminations. The second stack of laminations thus provides a coil winding area about which an electrically conductive coil can be positioned for introducing flux into a rotor that is received within the aligned rotor openings of the first stack of laminations, in order to provide a magnetic inductor circuit.

In such conventional C-frame two pole motors, the outer cross sectional shape of the coil winding area of the second stack of laminations is typically square when the stack height of the motor equals the width of the coil winding area cross section. This is the most efficient stack height with respect to copper usage in the electrically conductive coil because the ratio of the perimeter to the cross sectional area of the coil winding area is at a minimum. As the stack height of the laminations is increased, to increase the horsepower output of the motor, the cross sectional area of the coil winding area becomes more and more rectangular and the ratio of the perimeter to the area of the winding area becomes larger and less efficient. Also, reducing the stack height to make lower horsepower output motors causes the cross sectional area of the coil winding area to become more rectangular and therefore, also less efficient. The legs in

the first stack of laminations and the second stack of laminations that form the coil winding area typically have approximately equal cross sectional areas.

For two pole motor constructions, it has been discovered that both of the spaced side legs of the first stack of laminations can be usefully employed for coil winding purposes, whether made in the typical four-sided (square or rectangular) shape or in a higher order (greater than four sides up to a partial or full circular) shape. In either such case, if the coil winding areas of the spaced side legs in the first stack of laminations are positioned in proximity to the aligned rotor openings and rotor, several important advantages can be achieved. This construction permits electrically conductive coils to be mounted over the spaced side legs, thus providing a greater and/or more efficient flow of magnetic flux through the rotor of the magnetic inductor circuit. Also, the electrically conductive wire forming the electrically conductive coil that is positioned over each of the spaced side legs has less than one-half the length of a single electrically conductive coil in a conventional C-frame motor construction, and the diameter of the electrically conductive wire can be reduced, as well.

The use of less than one-half the length for the electrically conductive coil mounted on each pair of spaced side legs of the first stack of laminations in a two pole motor is due to the greater winding length and smaller mean winding diameter for the two electrically conductive coils positioned on the spaced side legs as compared to a single electrically conductive coil in a conventional C- frame motor construction. As a result, there is a shorter wire length for each of the electrically conductive coils that are positioned over one of the spaced side legs.. Additionally, there can be a reduction in the diameter of the electrically conductive wire for both electrically conductive coils. It is believed that the wire diameter can be reduced because of the shorter wire length of each electrically conductive coil, the greater winding surface area of the two electrically conductive coils and the proximate location of the spaced electrically conductive coils on the spaced side legs of the first stack of laminations relative to the aligned rotor openings and rotor.

The aforementioned proximate location of the electrically conductive coils in a two pole motor provides a more efficient flow of magnetic flux from the magnetic inductor circuit through the poles and into the rotor of the motor. In some instances, the overall dimension of the motor can be reduced to also reduce the length of the flux path, as well. In fact, performance tests have established that two pole motors constructed with this construction have a greater overall efficiency than conventional C-frame motors of the type described above. For example, this improved motor efficiency was established where the outer cross sectional side leg shape had a higher order greater than four sides, along with savings in copper usage. However, this improved motor efficiency is also possible even where the outer cross sectional configuration of the side legs have the typical four-sided (square or rectangular) configuration.

With respect to four pole motors, current four pole motors are typically manufactured as an annular or donut shaped element with four poles equidistantly spaced about the periphery of the annular or donut shaped element. In some designs, a square or rectangular shaped element is chosen in lieu of the annular or donut shaped element. An annular or other closed shape construction is chosen since it produces the shortest magnetic path in the most economical design that can be adapted to a variety of different end uses. For example, the magnetic flux around an annular or donut shaped element is split at each pole in two different paths and comes off each pole in a direction generally perpendicular to the center of each pole. As will be seen in the discussion that follows, such flux path movement while useful in current designs nonetheless creates inherent limitations in improving the cost and operating efficiency of such motors.

In the new and improved twin bobbin four pole construction of the present invention, spaced pairs of legs extend from opposite sides of a four pole central portion which includes a rotor opening for receiving a rotor. At the free end of each of the spaced legs, an end leg extends across to each of such spaced legs. Bobbins are mounted over each leg of the spaced pairs of legs on opposite

sides of the central portion or about each of the end legs, depending on the design that is chosen. In either case, substantial savings are possible as a result of the "foot print" of such designs, as well as in the amount of material required for each electrically conductive coil wound about each insulating bobbin. For example, an electrically conductive coil that is positioned over each of the spaced side legs on opposite sides of the central portion can have less than one- half the length of a single electrically conductive coil, in an equivalent magnetic inductor circuit, and the diameter of the electrically conductive wire can be reduced, as well. By positioning an electrically conductive coil on each of the spaced legs, a longer winding length with smaller mean coil winding diameter is provided, resulting in a substantially shorter length for the electrically conductive wire that forms each electrically conductive coil. Additionally, there can be a reduction in the diameter of the electrically conductive wire and a shorter wire length of each electrically conductive coil, for the reasons explained above.

In addition, where insulating bobbins with wound electrically conductive coils are mounted over each pair of stacked legs on opposite sides of the central portion, it may also be possible to provide improved operating performance and efficiency over current four pole motors. In part, this may be due to the greater cross sectional area of the new and improved construction even though the total lamination material used is less.

In certain motor constructions of the present invention, the combined predetermined outer cross sectional configuration of the spaced side legs may have the typical four-sided (square or rectangular) configuration; however, in certain designs, a higher order greater than four sides outer cross sectional shape may be employed in order to produce an even greater savings in the amount of electrically conductive wire required, as compared to typical polygonal cross sectional configurations. This can be further understood by reference to my aforementioned copending patent applications.

In the discussion that follows, the present invention discloses new and improved two pole and four pole motor constructions of the type generally described above, as well as new and improved methods of manufacturing such motor constructions, also with improved efficiency and lower material usage. Background Art

Among the several objects and advantages of the present invention include:

The provision of new and improved low cost motors, including two pole and four pole motors; The provision of new and improved low cost and high efficiency motor constructions;

The provision of the aforementioned motor constructions which employ several different types of twin bobbin constructions;

The provision of the aforementioned motor constructions which have a substantial reduction in the amount of material required;

The provision of the aforementioned motor constructions which enjoy substantial material savings in the amount of material required for electric conductive coils and, in certain instances, also in the magnetically conductive means forming the magnetic inductor circuit; The provision of the aforementioned motor constructions which further include additional material savings in other components used in such motors;

The provision of the aforementioned motor constructions which, despite having substantial material savings in the construction of such motors, nonetheless provides better efficiency and overall performance than prior art motors;

The provision of the aforementioned motor constructions which are readily adaptable to present manufacturing techniques, do not require substantial modifications or changes and provide highly efficient, better overall operating, lower cost motors than prior art constructions;

The provision of a new and improved method of manufacturing such low cost, high efficiency motors;

The provision of a new and improved method of forming such low cost, high efficiency motors with new and improved method or procedural steps that provide reliable, continuous operation without substantial modifications or changes in known manufacturing techniques.

Briefly stated, the low cost, high efficiency C-frame or two pole motor of the present invention includes magnetically conductive stacked laminations each having a spaced pair of end legs and a spaced pair of side legs. The combined stack configuration of such laminations provide spaced and stacked end legs and spaced and stacked side legs. At least one of the stacked end legs have aligned rotor openings for receiving a rotor. The coil winding area for each of the stacked side legs having a combined predetermined outer cross sectional configuration in order to enable an electrically conductive coil to be positioned about the coil winding area of each of the stacked side legs.

At least one end leg is integral with the spaced pair of side legs. The aligned rotor openings may be formed in the end legs of the laminations which are integral with the side legs. Preferably, one end leg of each lamination is separate from the spaced side legs with integral end leg. Each such separate end leg is attached to the spaced side legs at an outer free extremity thereof.

An electrically conductive coil, when positioned about a respective coil winding area of each of the stacked side legs, is positioned in close proximity to the poles of the motor, the aligned rotor openings and the rotor.

An electrically conductive wire forms each electrically conductive coil and is preferably layer wound in closely packed relationship in a plurality of juxtaposed rows in its positioned relationship on each coil winding area. Preferably, an insulating bobbin with wound electrically conductive coil is positioned on each coil winding area of the stacked side legs. The electrically conductive wire forming each electrically conductive coil has less than one-half the length of an electrically conductive wire forming a single electrically

conductive coil in an equivalent magnetic inductor circuit. Preferably, the electrically conductive wire for each of the spaced side legs has both a smaller predetermined length and a predetermined smaller diameter than an equivalent electrically conductive wire of a single electrically conductive coil in an equivalent magnetic inductor circuit.

The combined predetermined outer cross sectional coil winding area of each of the stacked side legs may have a four-sided (square or rectangular) outer cross sectional shape with each electrically conductive coil positioned about each of the stacked side legs also having a corresponding shape. Alternatively, the combined predetermined outer cross sectional coil winding area of each of the stacked side legs may have a higher order greater than four sides outer cross sectional configuration with each electrically conductive coil positioned about each of said stacked side legs having a corresponding shape, as well.

The motor preferably has first and second stacks of laminations. The first stack of laminations include magnetically conductive stacked laminations each having an end leg and a spaced pair of side legs. The spaced pair of side legs are attached at one end to the end leg and terminate at an opposite end in an outer free extremity. The combined stacked end legs and spaced pair of stacked side legs provide the first stack of laminations. Rotor openings are provided in the end leg of each lamination that is aligned with the rotor openings of adjacent stacked end legs in order to provide an aligned rotor opening in the stacked end legs for receiving a rotor. Each of the stacked side legs have a combined predetermined outer cross sectional configuration coil winding area. An electrically conductive coil is positioned about the coil winding area of each of the stacked side legs. A second stack of laminations comprising a corresponding number of separate magnetically conductive stacked laminations are attached to the outer free extremity of the spaced pair of stacked side legs of the first stack of laminations in order to provide a combined magnetic inductor circuit therethrough.

The motor has pole shading elements positioned in openings surrounding the aligned rotor opening which are in proximity to the poles of the motor. Both of the pole shading elements on the upper end of the aligned rotor opening are preferably angled or curved toward the center between the stacked side legs in order to reduce the width of and/or the spacing between the stacked side legs and thus the overall dimension of the motor.

The present invention also discloses a new and improved method of forming C-frame or two pole motors by forming C-frame laminations each having an end leg integral with spaced side legs from an elongated strip of magnetically conductive material. Adjacent C-frame laminations are stamped from the elongated strip with the integral end legs and spaced side legs of each lamination in generally opposed mirror image relationship to one another with the spaced side legs extending longitudinally along the length of the strip. The spaced side legs are formed with a combined predetermined outer cross sectional configuration coil winding area when the laminations are stacked. Two separate end legs are formed for attachment to the outer free extremities of each pair of spaced side legs, at least one of the separate end legs being formed from the elongated strip.

Preferably, at least some of the separate end leg laminations are formed from me elongated strip between the spaced legs of the C-frame laminations. At least some of the separate end leg laminations may also be formed from outside of the confines of the elongated strip. At least some of the separate end leg laminations may also be formed from a separate elongated strip of magnetically conductive material. In certain instances, at least two separate end leg laminations may be formed from the elongated strip between the opposed and spaced side legs of adjacent C-frame laminations. Complementary fastening elements may also be formed between the opposed and spaced side legs of adjacent C-frame laminations for attachment to complementary fastening elements formed in separate end leg laminations.

For four pole motors, the low cost, high efficiency four pole motor of the present invention includes magnetically conductive stacked laminations providing a first stack of laminations each having a four pole central portion with a rotor opening and two pairs of side legs. Each spaced pair of side legs extend from opposite sides of the central portion generally in mirror image relationship with one another and terminate in an outer free extremity. The combined stacked laminations provide spaced pairs of stacked side legs on opposite sides of stacked central portions having aligned rotor openings for receiving a rotor. Each of the stacked side legs of the stacked spaced pairs of side legs having a combined predetermined outer cross sectional configuration. Separate magnetically conductive stacked laminations forming two stacks each provide a second stack of laminations for attachment to the outer free extremities of one pair of stacked side legs in the first stack of laminations. Each of the second stack of laminations have a combined predetermined outer cross sectional configuration. At least one electrically conductive coil is positioned about the combined predetermined outer cross sectional configuration of at least one of each of the stacked side legs of the first stack of laminations or about each of the second stack of laminations.

In one of such designs, an electrically conductive coil is positioned about each of the stacked side legs of the first stack of laminations prior to the attachment of the second stack of laminations to the outer free extremities of each pair of stacked side legs in the first stack of laminations. In another design, an electrically conductive coil is positioned about each of the second stack of laminations prior to attachment to the outer free extremities of each pair of stacked side legs of the first stack of laminations.

The combined predetermined outer cross sectional configuration of one of such designs provides each of the stacked side legs with a four sided (square or rectangular) outer cross sectional shape with each electrically conductive coil positioned about each of the stacked side legs having a corresponding shape. In another design, the combined predetermined outer cross sectional configuration

of such stacked side legs provides a higher order greater than four sides outer cross sectional shape with each associated electrically conductive coil having a corresponding shape. In still another of such designs, the combined predetermined outer cross sectional configuration of each of the second stack of laminations has a higher order greater than four sides outer cross sectional shape with each of the electrically conductive coils positioned about each of the second stack of laminations having a corresponding shape.

In those constructions where each of the electrically conductive coils are positioned about each of the stacked side legs, such coils are positioned in close proximity to the aligned rotor openings of the stacked central portions and the rotor.

An electrically conductive wire forms each electrically conductive coil and is layer wound in closely packed relationship in a plurality of juxtaposed rows in its positioned relationship on each coil winding area. Preferably, an insulating bobbin with wound electrically conductive coil is positioned on each combined predetermined coil winding area in the first stack of laminations in one motor construction and in the combined predetermined coil winding area of the second stack of laminations in the other motor construction.

Where the motor design employs spaced stacked side legs on each side of the central portion with an electrically conductive coil wound about each of the stacked side legs, less than one-half the length of an electrically conductive wire is used in forming each electrically conductive coil, as compared with an electrically conductive wire forming a single electrically conductive coil in an equivalent magnetic inductor circuit. The electrically conductive wire in each such electrically conductive coil not only has a predetermined shorter length, but also can have a predetermined smaller diameter than a single electrically conductive coil in an equivalent magnetic inductor circuit.

In an alternative embodiment, U-shaped laminations each having a stacked pair of side legs for association with electrically conductive coils can be

attached to opposite sides of a base lamination having a rotor opening for receiving a rotor.

The present invention also discloses a new and improved method of forming four pole motors from an elongated strip of magnetically conductive material by stamping from the elongated strip a central portion with a rotor opening and two spaced pairs of side legs extending from opposite sides of the central portion in general mirror image relationship to each other. Each of the two spaced pairs of side legs are formed with a combined predetermined outer cross sectional configuration. Separate end leg laminations for attachment to the outer free extremities of the spaced pair of side legs are then formed, at least one of the separate end leg laminations being formed from the elongated strip.

Preferably, at least some of the separate end leg laminations are formed from the elongated strip between the spaced pairs of side legs. At least some of the separate end leg laminations may also be formed from outside of the confines of the elongated strip. At least some of the separate end leg laminations may also be formed from a separate elongated strip of magnetically conductive material. In certain instances, at least two separate end leg laminations may be formed from the elongated strip between the opposed and spaced legs of adjacent laminations. Complementary fastening elements may also be formed between the opposed and spaced side legs of adjacent laminations for attachment to complementary fastening elements forming separate end leg laminations.

Preferably, the method includes the forming of adjacent laminations with one pair of spaced side legs from each of said laminations being connected to one another during the manufacturing process, but then being subsequently separated from one another. At least some of the end leg laminations are formed from the elongated strip between the spaced pair of side legs of adjacent laminations.

These and other objects and advantages of the present invention will become apparent from the description that follows.

Brief Description of the Drawings

In the drawings, Figure 1 is a perspective view of one form of low cost, high efficient twin bobbin C-frame motor construction of the present invention;

Figure 2 is an exploded side elevational view of the twin bobbin C- frame motor shown in Figure 1 ;

Figure 3 is a side elevational view of the twin bobbin C-frame motor illustrated in Figure 1 ;

Figure 4 is a top plan view of the twin bobbin C-frame motor as illustrated in Figure 1 ; Figure 5 is a sectional view of the twin bobbin C-frame motor shown in

Figure 1, as viewed along lines 5-5 of Figure 3;

Figure 6 is a sectional view of the twin bobbin C-frame motor illustrated in Figure 1 as viewed along lines 6-6 of Figure 4;

Figure 7 is a perspective view of a modified form of twin bobbin C- frame motor utilizing a typical four-sided (square or rectangular) coil winding area for each of the stacked side legs of the C-frame laminations with correspondingly shaped electrically conductive coils;

Figure 8 is an exploded perspective view of the modified form of twin bobbin C-frame motor shown in Figure 7; Figure 9 is a side elevational view of the modified form of twin bobbin

C-frame motors shown in Figure 7;

Figure 10 is a top plan view of the modified twin bobbin C-frame motor shown in Figure 7;

Figure 11 is an enlarged side elevational view of a C-frame lamination used in the modified twin bobbin C-frame motor shown in Figures 7-10 of the drawings;

Figure 12 is an enlarged side elevational view of the twin-bobbin C- frame motor shown in Figure 9

Figure 13 is a top plan view illustrating the die layout used in the method of manufacturing C-frame laminations and end laminations in one method of the present invention;

Figure 14 is a side elevational view of a modified form of twin bobbin C-frame motor according to the present invention;

Figure 15 is a top plan view of a die layout used in the modified form of twin bobbin C-frame motor shown in Figure 21 ;

Figure 16 is a die layout view illustrating the method of manufacturing the modified C-frame and end laminations of the motor illustrated in Figures 21 -22 of the drawings; and

Figure 17 is a die layout view illustrating one method for forming the Figures 7-11 embodiment;

Figure 18 is a perspective view of one form of low cost, high efficiency twin bobbin four pole motor construction of the present invention; Figure 19 is a perspective view of the twin bobbin four pole motor with the rotor bracket and rotor removed;

Figure 20 is an exploded side elevational view of the twin bobbin four pole motor shown in Figure 19;

Figure 21 is a side elevational view of the twin bobbin four pole motor illustrated in Figure 19;

Figure 22 is a top plan view of the twin bobbin four pole motor illustrated in Figure 19;

Figure 23 is a sectional view of the twin bobbin four pole motor shown in Figures 18-19, as viewed along lines 23-23 of Figure 21; Figure 24 is a sectional view of the twin bobbin four pole motor illustrated in Figure 18-19, as viewed along lines 24-24 of Figure 22;

Figure 25 is a perspective view of a modified form of twin bobbin four pole motor utilizing a typical four-sided (square or rectangular) coil winding area for each of the stacked side legs of a base or first stack of laminations with correspondingly shaped electrically conductive coils;

Figure 26 is an exploded perspective view of a modified form of twin bobbin four pole motor shown in Figure 25;

Figure 27 is a side elevational view of the modified form of twin bobbin four pole motor shown in Figure 25; Figure 28 is a top plan view of the modified twin bobbin four pole motor shown in Figure 25;

Figure 29 is an enlarged side elevational view of the twin bobbin four pole motor shown in Figure 27;

Figure 30 is a top plan view illustrating the die layout used in the method of manufacturing base and end laminations used in the Figures 18-24 embodiment;

Figure 31 is a side elevational view of a modified form of twin bobbin four pole motor according to the present invention;

Figure 32 is a top plan view of the modified form of twin bobbin four pole motor shown in Figure 31 ;

Figure 33 is a top plan view of a die layout used in the modified form of twin bobbin four pole motor shown in Figure 31-32;

Figure 34 is a top plan view illustrating the die layout used in the manufacture of the base and end laminations illustrated in the Figures 25-29 embodiment;

Figure 35 shows a modified form of four pole motor within the present invention;

Figure 36 is an exploded side elevational view of the components used in the Figure 35 motor; Figure 37 is a top plan view illustrating the die layout for forming the base lamination used in the motor illustrated in Figure 35;

Figure 38 is a top plan view of the die layout for forming the U-shaped laminations used in the Figure 35 motor;

Figure 39 is a side elevational view of another modified twin bobbin four pole motor having opposed twin bobbins at opposite ends of the motor; and

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Figure 40 is an end elevational view of the modified four pole motor shown in Figure 39.

Corresponding reference numerals will be used throughout the various figures of the drawings. Best Mode for Carrying Out the Invention

The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptions, variations, alternatives and uses of the invention, including what I presently believe is the best mode of carrying out the invention.

In the new and improved motor designs of the present invention as discussed below, it will be seen that the spaced side legs of the motor laminations can be usefully employed for coil winding purposes in order to provide new and unexpected results. Further, the present invention discloses and new and improved method for manufacturing such improved motor constructions.

For a description of C-frame or two pole motors and their methods of manufacture, reference is first made to Figures 1-17, which will be followed by a description of four pole motors and their methods of manufacture as shown in Figures 18-40.

The C-frame motor or two pole constructions of the present invention include several different embodiments as illustrated in Figures 1-6 of the drawings; Figures 7-12 of the drawings, and Figures 14-15 of the drawings. In addition, several methods of manufacturing such modified C-frame motors are illustrated in Figures 13, 16 and 17 of the drawings.

Although there are common features used in the various C-frame or two pole motor constructions of Figures 1-6; 7-12 and 14-15 of the drawings, it will also be appreciated that each of the aforementioned C-frame motor

constructions have unique and specific features that differ from each other, as will be explained in detail below.

As illustrated in the Figures 1-6 embodiment, the C-frame two pole motor 1 includes a first stack of laminations 3 formed from a series of magnetically conductive stacked laminations of identical configuration each having an end leg 5 and a spaced pair of side legs 7, 7. The spaced pair of side legs 7, 7 are attached at one end to the end leg 5 and terminate at an opposite end in an outer free extremity. The combined stacked end legs 5 and spaced pair of side legs 7, 7 provide the first stack of laminations 3. A rotor opening 9 is provided in the end leg 5 of each lamination that is aligned with the rotor openings 9 of adjacent stacked end legs 5 in order to provide an aligned rotor opening 9 in the stacked end legs 5 for receiving a rotor 11, as illustrated in Figure 3 of the drawings. The rotor 11 is made up of a series of stacked laminations having aluminum die cast bars and end rings. The C-frame two pole motor 1 is of the shaded pole motor type which includes shading coils to produce starting torque and rotation of the rotor 11. For this purpose, each of the laminations is provided with generally diametrically opposed pairs of openings 13, 13 and 15, 15, each cooperating pairs of openings 13, 15 and 13, 15 receive a large and small shading coil 17, 19, respectively, as illustrated in Figure 1 of the drawings. Each of the shading coils 17, 19 are formed by a loop of copper or other electrical conductor which is arranged to encircle one of the poles 21, 21 of the two pole motor, the poles 21, 21 being offset by the generally opposed reluctance gaps 23, 23 on opposite sides of the opening 9. Each of the larger and smaller shading coils 17, 19 are designed to be received in one of the opposed pairs of apertures 13, 13 at one end while being positioned in proximity to one another by the intersecting openings or apertures 15, 15 at another end. Typically, the shading coils are formed and welded to form two loops of conductive material which are adapted to be received by the pairs of openings 13, 13 and 15, 15 for encircling a portion of one of the motor poles 21, 21 on opposite sides of the rotor opening 9. It will

be noted that the intersecting openings or apertures 15, 15 on one side of the aligned rotor opening 9 are arranged to be located generally between the stacked side legs 7, 7 of the first stack of laminations 3 in order to reduce the width of and/or the spacing between the stacked side legs 7, 7 and thus the overall dimension of the motor 1. Note specifically that the intersecting openings or apertures 15, 15 on one side of the aligned rotor opening 9 are located at the intersection of end leg 5 with one of the side legs 7. As a result, the pole shading elements 17, 19 in the upper portion of the aligned rotor opening 9 are angled or curved toward the center between the stacked side legs 7, 7 in order to reduce the combined width of and/or the spacing between stacked side legs 7, 7 and thus the overall width dimension of the motor. Reducing the overall width dimension reduces the flux path, increasing the efficiency of the motor, as will be discussed further below.

A pair of spaced C-shaped mirror image openings 25, 25 are provided on opposite sides of the first stack of laminations 3 in order to receive mounting screws that support a rotor bracket (not shown) for supporting the rotor 11 for rotation relative to the aligned rotor opening 9, as is well-known in the art.

Each of the stacked side legs 7, 7 of the first stack of laminations 3 have a combined predetermined outer cross sectional configuration coil winding area 27. In the Figures 1-6 embodiment, the combined predetermined outer cross sectional configuration coil winding area has a generally circular outer cross sectional shape, as best illustrated in Figures 2-5 of the drawings. Specifically, each of the stacked side legs 7, 7 have a substantially circular shape at least along opposed spaced sections 29, 29 thereof with opposed spaced flat areas 31, 31 along other opposed spaced sections thereof.

For purposes of the present invention, the term "higher order greater than four sides" includes a generally circular outer cross sectional shape including a full circular shape, a partially circular shape, a substantially circular shape at least along opposed spaced sections thereof or other modified shapes having a shorter outer peripheral length other than a square or rectangular shape.

Thus, a hexagonal or other greater than four-sided shape may also be included. A square or rectangular shape, on the other hand, is considered to have a "four- sided" shape.

Each of the generally circular outer cross sectional shapes 27 of the spaced side legs 7, 7 are constructed with a different progressive width, as illustrated in Figures 2-5 of the drawings, in order to provide an incrementally stair-stepped winding area on opposite sides of a center line that produces the generally opposed spaced circular sections 29, 29 in the Figures 1-6 illustrated embodiment. The manner in which the different progressive widths are formed in adjacent stacked laminations, in order to produce the generally circular outer cross sectional shape 27 for the coil winding area of each of the stacked side legs 7, 7, will be further understood in the discussion below.

A pair of insulating bobbins 33, 33 with previously wound electrically conductive coil or wire 35 are capable of being mounted on each of the spaced stacked legs 7, 7. Each of the insulating bobbins 33 are generally circular in shape corresponding to the generally circular outer cross sectional shape 27 of each of the stacked side legs 7, 7, thus producing a substantial reduction in the amount of material required for the electrically conductive wire or coil 35, resulting in substantial cost savings in the amount of material required for the electrically conductive coil or wire 35.

After each insulating bobbin 33 with wound electrically conductive coil or wire 35 is mounted on each of the stacked side legs 7, a second stack of laminations 37 formed by a corresponding number of separate magnetically conductive stacked laminations are attached to the first stack of laminations 3, through the complementary shaped male and female fastening elements 39, 41, as illustrated in Figures 1, 2 and 6 of the drawings. Each of the second stack of laminations 37 form a second or separate end leg. Thus, the first stack of laminations 3 have separate legs including an end leg 5 and two spaced side legs 7, 7 in a general U-shaped configuration, while the separate magnetically conductive stacked laminations forming the second stack of laminations 37

provide a separate end leg for attachment to the first stack of laminations 3 in order to complete a magnetic inductor circuit for the C-frame motor 1. It will be understood that the two spaced side legs 7, 7 may be attached in an alternative embodiment to the end leg laminations 37 for subsequent attachment to the end leg laminations 5 after positioning of an insulating bobbin 33 with wound electrically conductive coil 35 on at least one and preferably both of said spaced side legs 7, 7. For this purpose, complementary male and female fastening elements 39, 41 would be associated with the outer free extremities of the spaced side legs 7, 7 and end leg laminations 5. For attaching the first and second stack of laminations 3, 37, respectively, to one another in the Figures 1-6 embodiment, the outer free extremities of each of the stacked side legs 7, 7 are each provided with an outwardly extending male tab 39 for complementary reception within a complementary shaped recess or opening 41 formed in the second stack of laminations 37. As will be seen from e discussion that follows, the male tabs 39 could be provided on the second stack of laminations 37 with corresponding female recesses 41 in the first stack of laminations 3, as may be desired. In either case, the shape of the male tabs 39 and the complementary shaped recesses 41 have an irregular shape that provides greater interfitting engagement between the first and second stack of laminations 3, 37, respectively.

It will be noted that when each of the insulating bobbins 33 with wound electrically conductive coil or wire 35 is mounted on each of the stacked side legs 7 of the first stack of laminations 3, each electrically conductive coil 35 is mounted in close proximity to one motor pole 21, the aligned rotor opening 9 of the first stack of laminations 3 and the rotor 11. Additionally, the electrically conductive wire that forms at least one electrically conductive coil 35 has less than one-half the length of an electrically conductive wire forming a single electrically conductive coil in an equivalent magnetic inductor circuit. It will be appreciated that there is a greater surface winding area of the two electrically conductive coils 35, one of which is positioned on each of the stacked side legs

7 as compared to a single electrically conductive coil in a conventional C-frame motor. Because of the greater surface winding area, there is a greater winding length and smaller winding diameter for each of the two electrically conductive coils 35 as compared to a single electrically conductive coil. This results in a shorter wire length for each of the electrically conductive coils 35 that are positioned over one of the stacked side legs 7.

Further, the electrically conductive wire forming the electrically conductive coil 35 may also have a smaller diameter than a corresponding electrically conductive wire of a single electrically conductive coil in an equivalent magnetic inductor circuit. As explained above, this is believed due to the shorter wire length, the greater surface winding area and the proximate location of the spaced electrically conductive coils 35, 35 on the spaced side legs 7, 7 relative to the respective motor poles 21, 21, the aligned rotor opening 9 and the rotor 11. The aforementioned proximate location of the electrically conductive coils 35, 35 also provides a reduction in the magnetic inductor circuit flux path, thus providing a greater and/or more efficient flow of magnetic flux through the poles 21 and into the rotor 11. A reduction in the flux path may also result from the reduction in the width of the stacked side legs 7, 7, providing a reduction in the overall dimension of the motor and/or a reduction in the magnetic inductor circuit flux path and enabling a greater and/or more efficient flow of magnetic flux through the poles 21, 21 and into the rotor 11 of the motor 1. By comparing Figures 11-12 of the drawings, it will be seen that the upper intersecting openings 15, 15 are located in such a position as shown in Figure 11 as to cause the pole shading elements 17, 19 as shown in Figure 12 to be angled or curved toward the center between the stacked side legs 7, 7. As a result, the combined width of and or the spacing between the stacked side legs 7, 7 and thus the overall dimension of the motor 1 can be reduced by removing material along the outer or marginal side edges of the stacked side legs 7, 7. This has the

practical result of providing a more efficient flow of magnetic flux through the poles 21, 21 into the rotor 11.

Performance tests have established that motors so constructed have greater overall efficiency than conventional C-frame motors of the prior art. This was achieved in spite of the substantial reduction in the amount of material required for the electrically conductive coil 35 or as a result from the substantially circular outer cross sectional shape 27 of the stacked side legs 7, 7. This improvement in motor efficiency is also believed possible even where the outer cross sectional configuration of the stacked side legs 7, 7 has a typical four-sided (square or rectangular) configuration since the flux through the poles and rotor can be increased by the proximate location of the electrically conductive coils 35, 35 and/or the overall dimensional reduction of the motor, as described above.

A four-sided construction is illustrated in Figures 7-12 of the drawings where the C-frame two pole shaded pole type motor 51 is shown. The motor 51 is similar in all respects to the motor 1, with the exception of the following differences. First, each of the stacked side legs 7, 7 have a combined predetermined outer cross sectional configuration coil winding area that is of the typical four-sided (square or rectangular) shape. This enables an insulating bobbin 53 with wound electrically conductive coil or wire 55 having a corresponding shape to be mounted over the outer cross sectional configuration coil winding area 27 of each of the stacked side legs 7.

Even though there is a greater amount of electrically conductive wire used in forming the electrically conductive coil 55, as compared to the higher order greater than four side shape coil winding area 27 in the Figures 1-6 embodiment, it has nonetheless been found that the Figures 7-11 construction provides substantial cost reductions and in some cases, better operating efficiency over conventional C-frame motors. As explained above, this is believed to be due to shorter wire length, the greater surface winding area and the proximity of the electrically conductive coils 55 on each of stacked side legs

7, 7 relative to the rotor opening 9 and rotor 11 when mounted on the stacked side legs 7, 7. The magnetic inductor circuit flux path is reduced by the reduction in width of and/or the spacing between the spaced side legs due to the re-positioning of at least part of the pole shading elements 17, 19 between the stacked side legs 7, 7, as explained above.

The method of forming C-frame laminations of the type illustrated in Figures 1-6 of the drawings can best be understood by reference to Figure 13 of the drawings. As shown in Figure 13 of the drawings, one preferred method of forming each of the magnetically conductive stacked laminations 3 that form the first stack of laminations 3 includes the manufacture of adjacent C-frame laminations 3, 3 in generally opposed mirror image relationship to one another with the spaced side legs 7, 7 of each lamination 3 extending longitudinally in the Figure 16 illustration and with the separate end leg lamination 37 illustrated as being formed between the spaced legs 7, 7 of opposed mirror image laminations 3, 3. A second end leg lamination 37 is also illustrated in phantom lines as being formed at one end of the upper lamination 3, if desired, although it will be appreciated that some or all end leg laminations 37 may be formed from a separate strip of magnetically conductive material, if desired.

In the Figure 13 die layout, it will be seen that the opposed mirror image laminations 3, 3 are formed with interfitting male and female fastening elements 39, 41 in aligned spaced legs 7, 7 of opposing mirror image laminations 3, 3. On the other hand, the separate end leg lamination 37 formed within the confines of the spaced legs 7, 7 of the opposed mirror image laminations 3, 3 have complementary shaped female recesses 41, 41 while the other end leg lamination 37 has male fastening elements 39, 39. Thus, the lower lamination 3 with the extending male fastening tabs 39, 39 is adapted to be used in conjunction with the separate end leg lamination 37 within the confines of the spaced legs 7, 7 of the opposed mirror image laminations 3, 3 since it has spaced female recesses 41, 41 for complementary association therewith. The upper lamination 3 has female fastening recesses 41, 41 at the outer extremities

of the spaced legs 7, 7 for complementary association with the male fasteiiing tabs 39, 39 that extend from the other separate end leg lamination 37. Various adjustable widths can be formed in the spaced legs 7, 7 of adjacent laminations to produce the incremental stair-stepped generally circular outer cross sectional shape for the spaced legs 7, 7.

In some instances, it may be desirable to form both of the separate end leg laminations 37, 37 from the elongated strip between the opposed and spaced side legs of adjacent C-frame laminations which are in opposed mirror image relationship to one another. A suitable die layout for this purpose is illustrated in Figure 16 of the drawings. In order to accomplish this, the spaced side legs 7, 7 of each respective lamination must be spaced apart a further distance from one another, as illustrated in Figure 16 of the drawings. This produces a motor 101 of the type shown in Figures 14-15 of the drawings which is similar in all respects to the motor illustrated in Figures 1-6 of the drawings with the exception that the spaced and stacked side legs 7, 7 are spaced apart a distance greater than the Figures 1-6 embodiment in order to produce the pair of separate end leg laminations 37, 37 between the opposed mirror image adjacent laminations 3, 3 shown in Figure 16. It will be apparent that while this will provide savings in the manufacturing method, it may not result in the desirable horsepower output for the motor since the magnetic inductor circuit is enlarged, as will be apparent.

In the method for manufacturing C-frame laminations illustrated in Figures 7-12 of the drawings, it will be apparent that the more complex methods to produce the generally circular outer cross sectional shape for the legs 7, 7 in the Figures 1-6 embodiment will not be required. Thus, the simplified process shown in Figure 17 can be used. In this instance, the die layout of Figure 17 shows the Figures 7-12 laminations as being formed transverse to the feed of the strip 111 as compared to the method shown in Figure 13. It will be understood that the Figures 7-12 laminations could also be formed longitudinally of the strip, if desired.

In the Figure 17 die layout, the simplified process for forming the Figure 7-12 laminations includes a first stage or station for stamping the rotor laminations 11, 11 out of the mirror image laminations 33 to be formed. A second stage includes the stamping of the end lamination 37 which extends between the legs 7, 7 of each lamination 3 to be formed as well as the end lamination 37 at one outer edge of the laminations 3 to be formed. Finally, the left or right lamination 3 is stamped followed by the stamping of the other right or left lamination 3. The manufacturing process is thus much more simplified. With the Figures 1-6 embodiment, more steel will be required than the Figures 7-12 embodiment since the combined width of the legs 7, 7 of each lamination 3 in the Figures 7-12 embodiment can be reduced due to the re- positionment of the openings 15, 15 at the upper end of the aligned rotor opening 9, enabling material savings along the outer or marginal side edges of the legs 7, 7. On the other hand, the Figures 1-6 embodiment will have increased copper savings over the Figures 7-12 embodiment due to the higher order than four side outer cross sectional shape of the legs 7, 7, as explained above. However, all of the embodiments provide copper savings due to spaced stacked leg construction with wound electrically conductive coils, as explained above. While the preferred construction includes electrically conductive coils each having less than one-half of the electrically conductive wire of a single electrically conductive coil in an equivalent magnetic inductor circuit, it is possible to use only one such electrically conductive coil on a single stacked side leg or an electrically conductive coil on each stacked side leg where one of the electrically conductive coils has more turns of electrically conductive wire than the other, i.e., one electrically conductive coil has less than one-half of the electrically conductive wire and the other has more than one-half of the electrically conductive wire. Further, while the preferred method includes the use of spaced bobbins mounted over spaced stacked legs of a first stack of laminations with the subsequent attachment of end leg laminations to the spaced

stacked lamination legs, it is also possible to manufacture one-piece laminations with spaced stacked legs and then use split bobbins that are gear wound with electrically conductive wire, as described in some of my aforementioned patent applications. Now, a description of the four pole motor of the present invention will follow.

The twin bobbin four pole motor constructions of the present invention include several different embodiments as illustrated in Figures 18-24 of the drawings; Figures 25-29 of the drawings; Figures 31-32 of the drawings, Figure 35 of the drawings and Figures 39-40 of the drawings. In addition, several methods of manufacturing such four pole motors are illustrated in Figure 30; Figure 33; Figure 34; and Figures 37-38 of the drawings.

Although there are common features used in the various four pole motor constructions of Figures 18-24; 25-29; 31-32; 35-36; and 39-40 of the drawings, it will also be appreciated that each of the aforementioned four pole motor constructions have unique and specific features that differ from each other, as will be explained in further detail below.

As illustrated in the Figures 18-24 embodiment, the twin bobbin four pole motor 201 includes a first stack of laminations 203 formed from a series of magnetically conductive stacked laminations each having a four pole central portion 205 with two spaced pairs of side legs 207, 207 and 207, 207 extending from opposite sides of the central portion 205 generally in mirror image relationship with one another. In the Figures 19-24 embodiment, each of the spaced pair of side legs 207, 207 on each side of the central portion 205 are attached at one end to the central portion 205 and terminate at an opposite end in an outer free extremity. A combined stack of laminations 203 provides spaced pairs of stacked side legs 207, 207 on opposite sides of stacked central portions 205 providing a first stack of laminations 203. A rotor opening 209 is provided in the central portion 205 of each lamination that is aligned with the rotor openings 209 of adjacent central portions 205 in order to provide an

aligned rotor opening 209 in the stacked central portions 205 for receiving a rotor 211, as illustrated in Figure 21 of the drawings. The rotor 211 is made up of a series of stacked laminations having aluminum die cast bars and end rings. As illustrated in Figure 18 of the drawings, spaced frame or end bell elements 204, 204 extend on opposite sides of the first stack of laminations 203 and are threadably connected to one another through opposed threaded elements 206, 206, each of which are threadably associated with spaced ear elements 208, 208 that extend from each of the end bells or frames 204, 204. A rotor shaft 210, connected to the rotor 211, extends through the upper frame element 204 for connection to an element to be driven. Each of the end bells or frame elements 204, 204 have bearing supports (not shown) on an inside face thereof for rotatably supporting rotor 211 and rotor shaft 210 in desired rotatably mounted relationship.

The four pole motor 201 is of the shaded pole motor type which includes shading coils to produce starting torque and rotation of the rotor 211. For this purpose, each of the laminations are provided with generally diametrically opposed openings 213, 213 and 215, 215. Each of the openings 213 and 215 receive a rectangular or round shading coil 217, 219, respectively, as illustrated in Figures 21-22 of the drawings. The shading coils 217, 219 are formed by a loop of copper or other electrical conductor which is arranged to encircle the poles 221, 221, 221, 221 of the four pole motor 201. Each of the four poles 221, 221, 221, 221 of the four pole motor are offset by reluctance gaps 223, 223, 223, 223 positioned at approximately 0°, 90°, 180°, and 270° around the opening 209. It will be noted that the rectangular shading coils 217 are received in the relatively deep opening or notch 213 in one of the thickest parts of the central portion 205 while the rounded opening 215 is angularly offset to avoid a deep opening or notch in the central portion 205 which would interfere with the flux path while, at the same time, receiving rounded shading coil 219.

Each of the stacked side legs 207, 207 on each side of the four pole central portion 205 have a combined predetermined outer cross sectional

configuration coil winding area 227. In the Figures 1-7 embodiment, the combined predetermined outer cross sectional coil winding area is a higher order greater than four sides outer cross sectional shape, generally circular in shape, as best illustrated in Figures 20-23 of the drawings. Specifically, each of the stacked side legs 207, 207 on each side of the four pole central portion 205 have a substantially circular shape at least along opposed spaced sections 229, 229 thereof with opposed spaced flat areas 231, 231 along other opposite spaced sections thereof, as best illustrated in Figure 23 of the drawings.

For purposes of the present invention, the term "higher order greater than four sides" includes a generally circular outer cross sectional shape including a full circular shape, a partially circular shape, a substantially circular shape at least along opposed spaced sections thereof or other modified shapes having a smaller outer peripheral shape other than a square or rectangular shape. Thus, a hexagonal or other greater polygonal sided shape may also be included. A square or rectangular shape, on the other hand, is considered to have a "four- sided" shape.

Each of the generally circular outer cross sectional shapes 227 formed in each of the spaced side legs 207, 207 on opposite sides of the four pole central portion 205 are constructed with a different progressive width, as illustrated in Figures 20-23 of the drawings, in order to provide an incrementally stair- stepped winding area on opposite sides of the center line that produces the generally opposed spaced circular sections 229, 229 in the Figures 18-24 illustrated embodiment. The manner in which the different progressive widths are formed in adjacent laminations, in order to produce a generally circular outer cross sectional shape 227 for the coil winding area of each of the stacked side legs 207, 207 on opposite sides of the stacked four pole central portions 205, will be further understood in reference to the discussion below that describes the preferred method of producing such a construction.

A pair of insulating bobbins 233, 233 with previously wound electrically conductive coil or wire 235 are capable of being mounted on the spaced stack

legs 207, 207 on each side of the four pole central portion 205. Thus, the embodiment illustrated in Figures 18-24 of the drawings has a double twin bobbin construction in that the spaced pair of insulating bobbins 233, 233 are mounted on the spaced stack legs 207, 207 on each side of the four pole central portion 205. Each of the insulating bobbins 233 are generally circular in shape corresponding to the generally circular outer cross sectional shape 227 of each of the stacked side legs 207,207 on opposite sides of the four pole central portion 205, thus producing a substantial reduction in the amount of material required for the electrically conductive wire or coil 235, as explained above. A substantially circular outer cross sectional shape provides a cross sectional area with a shorter circumference for winding an electrically conductive wire that forms each electrically conductive coil. Additionally, the generally circular outer cross sectional shape enables the electrically conductive wire to be layer wound in closely packed relationship in a plurality of superimposed rows. Finally, a reduction in the diametrical size of the electrically conductive wire can also be achieved without sacrificing motor efficiency. As a result, substantial cost savings in the amount of material required for the electrically conductive coil or wire 235 wound about each insulating bobbin 233 will result.

After each insulating bobbin 233 with wound electrically conductive coil or wire 235 is mounted on each of the stacked side legs 207 to produce spaced pairs of insulating bobbins 233, 233 on opposite sides of the four pole central portion 205, a second stack of laminations 237 formed by a corresponding number of separate magnetically conductive stack of laminations are attached to the first stack of laminations 203, as illustrated in Figures 18-21 and 24 of the drawings. Each of the second stack of laminations 237 constitute a second or a separate end leg. Thus, the first stack of laminations 203 have a four pole central portion with spaced pairs of side legs 207, 207, and 207, 207 extending from opposite sides thereof, while the separate magnetically conductive stacked laminations forming the second stack of laminations 237, 237 provide a separate end leg for attachment to the outer free extremities of each pair of stacked side

- 29 -

legs 207, 207 on opposite sides of the four pole central portion 205. This completes a magnetic inductor circuit for the four pole motor 201.

For attaching the first stack of laminations 203 to each of the second stack of laminations 237, 237 in the Figures 18-24 embodiment, the outer free extremities of each of the upper pair of stacked side legs 207, 207, as seen in Figure 20 of the drawings, are each provided with an outwardly extending male tab 239 for complementary reception within a complementary shaped recess or opening 241 formed in the upper second stack of laminations 237. The lower pair of each of the stacked side legs 207, 207 on the opposite side of the four pole central portion 205 in the Figure 20 illustration, each have a recess or opening 241 formed in the outer free extremity of each of the stacked side legs 207, 207 for complementary reception of one of the spaced male tabs 239, 239 formed in the lower second stack of laminations 237.

As best illustrated in Figures 18-19, 21 and 24 of the drawings, it will be noted that when each of the insulating bobbins 233 with wound electrically conductive coil or wire 235 are mounted on each of the stacked side legs 207 of the first stack of laminations 203, each electrically conductive coil 235 is mounted in close proximity to one motor pole 221, the aligned rotor opening 209 of the first stack of laminations and the rotor 211. Each electrically conductive wire 235 forming each electrically conductive coil 235 has less than one-half the length of an electrically conductive wire forming a single electrically conductive coil in an equivalent magnetic inductor circuit. The use of less than one-half of the length for each electrically conductive coil 35 mounted on the side legs 207, 207, as compared to the length of a single electrically conductive coil, is due to the longer length and smaller mean diameter of each pair of electrically conductive coils 235 positioned in the spaced side legs 207, 207.

Additionally, the electrically conductive wire forming each electrically conductive coil 235 may also have a smaller diameter. The reduction in the diameter of the electrically conductive wire forming each electrically conductive

coil 235 is believed due to the shorter wire length of each electrically conductive coil 225, the greater winding surface area of each electrically conductive coil 235 and the proximate location of the spaced electrically conductive coils 235 on the spaced pairs of side legs 207, 207 on each side of the central portion 205 relative to the four poles 221, aligned rotor opening 209 and rotor 211.

It is also believed that the greater cross sectional area of the legs 207 in the new and improved construction, even where there is substantial savings in lamination material, may provide a greater and/or more efficient flow magnetic flux than the aforementioned prior art four pole motors. Greater overall efficiency may also be achieved in spite of the substantial reduction in the amount of material required for the electrically conductive coil 235, whether or not the combined predetermined outer cross sectional configuration of each of the stacked legs 207 have a four-sided (square or rectangular) configuration or a higher order greater than four sides outer cross sectional shape.

The embodiment of Figures 25-29 illustrate a four-sided construction for the spaced legs 207, 207 of the four pole motor 251. The motor 251 is similar in all respects to the motor 201 of the Figures 18-24 embodiment with the following differences. First, each of the stacked side legs 207, 207 on each side of the stacked central portion 205 in the first stack of laminations 203 have a combined predetermined outer cross sectional configuration coil winding area that is of the typical four-sided (square or rectangular) shape. This enables an insulating bobbin 253 with wound electrically conductive coil or wire 255 having a corresponding four-sided shape to be mounted over the four-sided outer cross sectional configuration coil winding area 227 of each of the stacked side legs 207, 207 on each side of the four pole central portion 205.

Except for the extra wire savings achieved in the Figures 18-24 embodiment due to the higher order greater than four sides outer cross sectional shape as compared to the four-sided shape of Figures 25-29, it has been found that the Figures 25-29 construction retains all of the other substantial cost

reductions in the same manner at the Figures 18-24 embodiment, when compared to prior art four pole motors.

The method of forming base and end leg laminations of the type illustrated in Figure 18-24 of the drawings can best be understood by reference to Figure 30 of the drawings. Figure 30 shows the die layout used in the method of manufacturing base and end leg laminations in the Figures 18-24 embodiment. As illustrated in Figure 30, the die layout shows two rows of base laminations 203, each lamination 203 having spaced side legs 207, 207 on opposite sides of the four pole central portion 5 as extending longitudinally with one of the separate end leg laminations 237 formed between opposed pairs of spaced legs 207, 207 in adjacent base laminations 203, 203. At the outer free extremity of one end of one of the spaced pairs of legs 207, 207, there is a male fastening tab 239, while the outer free extremity of the second pair of spaced legs 207, 207 on an opposite side of the four pole central portion 205 is provided with complementary shaped female recesses 241, 241. This pattern repeats throughout the die layout, thus facilitating stacking of adjacent formed base laminations 203 in a desired pattern. End leg laminations 237 formed between spaced pairs of legs 207, 207 of adjacent base laminations 203, 203 are provided with spaced male fastening tabs 239, 239 for complementary fastening engagement with female fastening recesses 241, 241 at one end of each of the base laminations 203. Second end leg laminations 237 are also illustrated as being formed between the two rows of base laminations 203, 203, the separate end leg lamination 237 being provided with spaced female recesses 241, 241 for cooperative fastening interengagement with male fastening tabs 239, 239 at an opposite end of each of the base laminations 203. It will be appreciated that adjacent laminations could be spaced apart a sufficient distance to enable a pair of laminations 237, 237, each being provided with spaced female recesses 241, 241, to be formed in the two rows of base laminations between adjacent laminations in each row. Alternatively, the end leg laminations with female recesses 241, 241 can be formed from a separate strip, if desired.

Various adjustable widths can be formed in adjacent laminations to produce the incremental stair-stepped generally circular outer cross sectional shape for the spaced stack legs 207, 207 on each side of the four pole central portion 205 of the first stack of laminations 203. In some instances, it may be desirable to form both the separate end leg laminations 237, 237 from the elongated strip between the opposed and spaced side legs 207, 207 of adjacent base laminations 203, 203. A suitable die layout for this purpose is illustrated in Figure 33 of the drawings. In order to accomplish this, the spaced side legs 207, 207 of each lamination 203 on opposite sides of the four pole central portion 205 must be spaced apart a further distance from one another, as illustrated in Figure 33 of the drawings. This produces a motor 201 of the type shown in Figure 31 of the drawings which is similar in all respects to the motor illustrated in Figure 18-24 of the drawings with the exception that the spaced and stacked side legs 207, 207 on each side of the four pole central portion 205 are spaced apart a distance greater than the Figures 18-24 embodiment in order to produce the pair of spaced end leg laminations 237, 237 between the spaced legs 207, 207 of adjacent laminations 203, 203. It will be apparent that while this will provide savings in the manufacturing method, it may not result in the desirable horsepower output for the motor 201 since the magnetic inductor circuit is enlarged.

There is one further difference in that the pair of separate end leg laminations 237, 237 each have alternate male and female fastening elements 239, 241. This alternate male/female fastening element 239, 241 for each separate end leg lamination 237 corresponds to the male and female fastening elements 239, 241 formed at the outer free extremities of spaced stacked legs 207, 207 on each side of the four pole central portion 205, as illustrated in Figure 33 of the drawings. As will be appreciated, this alternate male/female fastening construction for each of the end leg laminations 237 enables both of the end leg laminations to be formed between the spaced side legs of adjacent base laminations 203 that are being formed from an elongated strip.

This same alternate male/female fastening element construction may be used in forming base laminations where the spaced side legs have the typical four-sided (square or rectangular) configuration. This is illustrated in Figure 34 of the drawings. The Figure 34 die layout shows the spaced side legs 207, 207 on each side of the four pole central portion 205 as having the same width in order to produce a combined predetermined outer cross sectional configuration of four-sided (square or rectangular) shape. Between spaced side legs 207, 207 of adjacent laminations 203, the separate end leg laminations 237, 237 may be formed. In this instance as well, each of the end leg laminations 237, 237 have one male fastening tab and one female fastening recess 239, 241, respectively.

In lieu of attaching the side legs 207, 207 to the central portion 205 and securing separate end legs 237 to the outer free extremities of the side legs 207,

207, Figures 35-36 show a modified four pole motor 278 where U-shaped laminations 280 are formed with the end legs 237 integrally attached to the side legs 207, 207. The outer free ends of such side legs 207, 207 are provided with complementary male/female elements 239, 241 for complementary fastening engagement with female/male elements 241, 239 on opposite sides of the central portion 205.

The method of forming the Figures 35-36 modified four pole motor 278 is best illustrated in Figures 37-38 of the drawings. The base laminations 282 are formed with a central portion 205 having a rotor opening 209. The base laminations 282 are formed in a strip with complementary mating male/female elements 239, 241 between adjacent base laminations 282. The U-shaped laminations 280 are illustrated as being formed in Figure 38 from a strip of material in adjacent nested relationship, is illustrated. Subsequently, the base laminations 282 and U-shaped laminations 280 are stacked, electrical coils 235 are positioned over the spaced legs 207, 207, and the U-shaped laminations 280 are attached to the base laminations 282 as illustrated in Figures 35-36.

In all of the previous four pole motor constructions and methods of manufacture, the four pole motor constructions were illustrated as being of the

double twin bobbin four pole motor variety. In the four pole motor embodiment illustrated in Figure 39-40 of the drawings, the four pole motor is a twin bobbin four pole motor where the twin bobbins are not mounted on the spaced side legs of the base laminations, but rather on the separate end leg laminations that are attached to the free ends of the spaced side legs of the base lamination.

This is best illustrated in Figures 39-40 of the drawings where the motor 301 is illustrated as having a series of stacked base or stator laminations 303. Each of the stator laminations 303 have a four pole central portion 305 with spaced side legs 307, 307 extending on opposite sides of the central portion. A rotor opening 309 is formed in the four pole central portion 305 for receiving the rotor 311, as illustrated. The four slots 313 form the adjacent rotor opening 309 are used for the insertion of shading copper (not shown) along the lines of the Figures 1-7 and 8-11 embodiments. Four poles 321 are separated by four reluctance gaps 323 positioned at the 0°, 90°, 180°, and 270° positions around the opening 309, as illustrated. Thus, the rotor 311 rotates with respect to the four poles 321 in a manner similar to the Figures 18-24 and 25-29 embodiments.

Each of the stacked stator or base laminations 303 include a pair of U- shaped openings 323, 323 at opposite ends thereof between each pair of spaced side legs 307, 307 on each side of the four pole central portion 305. The U- shaped openings 323, 323 each receive bobbins 325 with wound electrically conductive coil 327 that are mounted on the stacked coil winding laminations 329, each of which collectively have a combined generally circular outer cross sectional shape, as illustrated in Figure 27 for receiving complementary shaped bobbins 325 about which the electrically conductive coil 327 is wound. As in the previous embodiments, the electrically conductive coil 327 is layer wound in closely packed relationship in a series of superimposed rows, as described in my aforementioned copending patent applications. The opposite free extremities of the spaced stack legs 307, 307 include spaced male bosses 331, 331 for complementary cooperative fastening interconnection relative to spaced

female openings 333, 333 formed in the separate stacked coil winding laminations 329. It will now be apparent that the four pole motor 301 thus includes spaced twin bobbins mounted on the separate end leg or coil winding laminations 329, 329 at opposite ends of the motor in the manner best illustrated in Figures 39-40 of the drawings.

While the preferred construction includes spaced twin bobbins each wound with an electrically conductive coil on opposite sides of a four pole central portion, it is possible to use only one such electrically conductive coil on a single stacked leg on opposite sides of the four pole central portion. Furthermore, while the spaced twin bobbins in the preferred construction each preferably has an electrically conductive coil with less than one-half of the electrically conductive wire of a single electrically conductive coil, one electrically conductive coil may have less than one-half of the electrically conductive wire while another electrically conductive coil in the twin bobbin construction may have more than one-half of the electrically conductive wire.

From the foregoing, it will now be appreciated that the novel and unique C-frame or two pole motor construction, illustrated as a twin bobbin C-frame motor, provides substantial material savings in the amount of material required, as compared with prior art designs. At the same time, the substantial reduction in motor material cost does not impair the operating performance or efficiency since the C-frame motors of the present invention have been designed with both end results in mind. The insulating bobbin assembly is also usefully employed in enhancing production and maximizing cost savings. The same is true of the method of the present invention which provides cost saving advantages over other prior art methods.

It will also now be appreciated that the present invention discloses several different and novel twin bobbin four pole motor constructions that provide substantial material savings as compared with prior art designs. At the same time, the substantial reduction in motor material costs does not affect the operating performance or efficiency, but rather, even with substantial material

savings, there can be improved operating efficiency over prior art designs. In addition, the novel methods of manufacturing the various four pole motor embodiments disclosed illustrates new and improved methods for achieving optimal manufacturing performance while producing four pole motor constructions having the improved savings and operating efficiency, as discussed above.

In view of the above, it will be seen that the several objects and advantages of the present invention have been achieved and other advantageous results have been obtained. As various changes could be made in the above constructions or methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.