Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
STATOR FOR MULTI ROTOR D.C.MAGNETIC MOTOR
Document Type and Number:
WIPO Patent Application WO/1980/001524
Kind Code:
A1
Abstract:
At least one armature (32, 34) is supported adjacent and in axial alignment with coaxial apertures (30, 31) in parallel magnetic pole plates (20, 22) of opposite polarity energized by a coil (24) extending therebetween. A plurality of equally spaced finger-like pole pieces (40, 42, 44, 46) connected with respective pole plate, extend in interdigitated relation parallel with the axis of the armature and in close spaced relation with respect to circumferential portions of its periphery.

Inventors:
MASON E (US)
Application Number:
PCT/US1979/001139
Publication Date:
July 24, 1980
Filing Date:
December 17, 1979
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
MASON E (US)
International Classes:
H02K16/00; H02K16/02; H02K23/02; H02K23/04; H02K23/26; H02K23/40; (IPC1-7): H02K16/00
Foreign References:
US3723796A1973-03-27
US3757149A1973-09-04
US0374959A1887-12-20
CH487529A1970-03-15
Other References:
See also references of EP 0036856A4
Download PDF:
Claims:
Claims
1. A motor assembly, comprising: magnetic motor frame¬ work means including a pair of spacedapart plates each hav¬ ing at least one transverse aperture coaxially aligned with the aperture in the opposite plate; an armature adjacent each plate in axial alignment with the aperture, said arma¬ ture being characterized by a winding having a plurality of axially extending segments and a commutator having a like plurality of segments and including a pair of commutator brushes each transversely spanning a plurality ofcommutator segments; housing means including bearings encompassing said framework for journalling said armature, said framework plates each having at least one integrally connected pole piece adjacent its' aperture normal to the plane of the plate and projecting parallel with the armature axis and in oppo¬ sition with respect to the pole piece on the opposite plate, each said pole piece being characterized by a transverse sur¬ face facing the periphery of said armature, the transverse dimension of said transverse surface being no greater than the transverse dimension of a plurality of armature winding segments equal in number to the number of commutator seg¬ ments spanned by the respective brush; and, magnetic field producing means connected with said plates for establishing a magnetic field, whereby said plates and their respective pole pieces are magnetized with respectively different po¬ larities to provide a magnetic flux circuit across the pe¬ riphery of said armature.
2. The motor assembly according to claim 1 in which said pole pieces are elongated and project equidistant from the respective said plate a dimension substan ially equal with respect to the axial length of said armature winding segments; and, means connected with the end portion of eac pole piece opposite the respective said plate for maintain ing said pole pieces in parallel spaced relation.
3. The motor assembly according to claim 2 in which said magnetic field producing means includes: a coil core tending between"and contacting said plates; and, a coil co axially surrounding said coil core.
4. The motor assembly according to claim 3 in which said connected means comprises: nonmagnetic spacer and bol means connecting the respective said pole piece with said opposite plate.
5. The motor assembly according to claim 3 or 4 in which each said pole piece projects beyond the opposing su faces of each said plate a distance at least equal with re spect to the axial length of said armature winding segment and in which said connected means comprises: a nonmagnetic disc abutting the respective ends of said pole pieces; and, nonmagnetic bolt means connecting said discs with the resp tive said pole piece.
6. The motor assembly according to claim 4 in which the spacing between the respective said pole piece and the opposite said plate is four times greaterthan the air gap between the respective pole piece and the periphery of said armature.
7. The motor assembly according to claim 1 in which said pair of plates are elongated and the apertures are dis posed in the respective end portions of the plates and in which said armature includes: a pair of armatures having their axes disposed in parallel relation, whereby said plat are magnetized with respectively opposite polarities and t magnetic force emanating from opposing surfaces of said co toward the respective end portions of each said plate are divided by the respective aperture therein and induced in the respective adjacent pairs of pole pieces and form a ma netic flux electromotive force on the winding of the respec tive armature.
8. The motor assembly according to claim 5 in which said armature includes: a pair of armatures having their axes disposed in coaxial alignment.
9. The motor assembly according to claim 7 in which each said pole piece connected with the respective said plate terminates in spaced relation with respect to the oppo¬ site plate a distance equal to four times the dimension of the air gap between the pole pieces and the periphery of the respective armature and further including: nonmagnetic means interposed in the spacing between said pole pieces and said plates for maintaining said pole pieces in parallel spaced relation.
Description:
STATORFORMULΗROTORD.C.MAGNEΠCMOTOR ^

TECHNICAL FIELD The present invention relates- to direct current motors and more particularly to a magnetic motor.

A direct current motor constructed in accordance with this invention finds particular application in industry where a high torque direct current motor, having an except tionally high starting torque, is needed. For example, for starting the Diesel engine of a relatively large size truck- tractor commonly referred to as a "big cam Diesel". The en- gines of these truck-tractors are usually left running in cold weather when the truck-tractor rig is parked out-of- doors for the reason that when the motor and motor oil becomes cold the engine cannot be turned over or started with any presently available starter. This results in an unnecessary waste of Diesel fuel as well as wearing the en¬ gine. Further, a direct current motor of this type is need¬ ed for mounting on the "dead" axle of a truck-tractor to assist the internal combustion engine on long uphill grades.

Background Art The most pertinent prior patents are believed to be my U.S.A. patent Nos. 3,651,355 and 3,723,796. These patents generally disclose multiple armature motors having the axis of the respective armatures arranged in parallel normal to the axis of a coil or coils as in patent No. 3,651,355 or parallel with the coil axis as in patent No. 3,723,796 with both patents featuring magnetic pole pieces surrounding dia¬ metrically opposite substantial portions of the respective armature periphery. This partial armature wrap-around

OMPI

feature of the magnetic pole pieces results in a back elec tromotive force (e.m.f.) opposing the magnetic attractive e. .f. on the armature winding thus reducing the efficienc of the motor and reducing its torque. In the present inve tion the back e.m.f. is eliminated by reducing the area of magnetic flux acting on the armature to an arc of the arma ture circumference spanning the number of the armature seg ments spanned by the respective armature brush contacting the cooperating commutator segments. This results in form a motor which has a substantially increased torque when co pared with a conventional similar size or rated A.C. or D. motor having the major portion of its armature periphery spanned by magnetic pole pieces or conventional field coil Other direct current high torque motors presently in use are generally characterized by the disadvantage of a r latively high amperage drag. This feature is particularly undesirable where, for example, the motor is utilized as t prime mover of a vehicle and has a constant amperage drag a constant voltage whether climbing, cruising or coasting downhill.

Disclosure of Invention This invention provides a motor having an amperage dr in proportion to the load and in which the amperage drag i automatically reduced when a cruising speed is reached and is further reduced to a minimum under little or no load. one embodiment a pair of armatures are supported in parall spaced relation between a pair of parallel spaced-apart ma netic pole plates energized by a central coil extending between the pole plates with its axis normal to the planes of the plates. A plurality of elongated pole pieces conne ed with the respective pole plate project toward and termi nate in spaced relation with respect to the opposite pole plate in interdigitated circumferential equally spaced re¬ lation about the periphery of the respective armature para lei to its axis and in close spaced relation with respect its periphery. That portion of each elongated pole piece adjacent the periphery. of the armature is limited to a wid no greater than the transverse dimension of any three seg¬ ments forming the armature winding. The respective elonga

ed pole pieces connected with the respective pole plate form magnetic poles of one polarity opposite the polarity of the pole pieces on the opposite pole plate to establish magnetic flux circuits for the respective armatures. The pole plate energizing coil is preferably wound at least two- in-hand about a rectangular coil core to provide an even number of wraps about the core. These coil forming wires are connected in series or in parallel to a source of direct cur¬ rent and brushes mounted on the respective commutator. In another embodiment, the axis of the two armatures are arranged in coaxial alignment normal to and on opposing sides of parallel opposite polarity pole plates having an energiz¬ ing coil centrally disposed coaxially therebetween. T:he re¬ spective elongated pole pieces, connected with the respective pole plate, project in opposite directions with respect to the respective pole plate in similar interdigitated circum- ferentially spaced relation about the periphery of the re¬ spective armature.

Brief Description Of The Drawings Figure 1 is a top view of one embodiment;

Figure 2 is a vertical cross sectional view taken sub¬ stantially along the line 2 2 of Fig. 1;

Figure 3 is an elevational view of one of the magnetic pole plates; Figure 4 is an exploded perspective view of the pole plates illustrating the relative position of the magnetic coil and magnetic pole pieces;

Figure 5 is a fragmentary cross sectional view illus¬ trating the transverse magnetic flux area between one of the magnetic pole pieces with respect to armature winding seg¬ ments;

Figure 6 is a view similar to Fig. 5 illustrating a larger size pole piece and the manner of limiting the trans¬ verse magnetic flux area between the pole piece and armature segments;

Figure 7 is a view similar to Fig. 4 illustrating the manner of extending the pole plates and adding a second pair of armatures;

^ sΕArr

Figures 8 and 9 are wiring schematics;

Figure 10 is a top view of another embodiment compris ing a pair of a ially aligned armatures;

Figure 11 is a vertical cross sectional view taken su stantially along the line 11 11 of Fig. 10;

Figure 12 is a perspective view of Fig. 10 with the coil and armatures removed for clarity; and,

Figure 13 " is an exploded perspective view of Fig. 12. The Best Mode For Carrying Out The Invention In the drawings, referring to Figs. 1 through 6, the reference numeral 10 indicates one embodiment of the motor which is rectangular in general configuration including a motor housing formed from nonmagnetic material comprising end walls 12 and 14 joined by side walls 16 and 18. The housing supports a motor framework 19 comprising a pair of generally rectangular identical magnetic material pole pla 20 and 22 disposed in parallel spaced-apart relation havin a magnetic coil 24 centrally disposed therebetween. The coil 24 comprises a magnetic material core 26, preferably rectangular in transverse section, for the purposes presen ly explained, which is rigidly joined centrally at one end to one of the pole plates and abuts the other pole plate when the motor is assembled as presently described.

The coil 24 is formed by a plurality of wraps or runs of wire wound one-in-hand or by pairs about the periphery the core 26. In the example shown, a pair of wires 28 and 29 (Figs. 8 and 9) are wound two-in-hand. The number of wraps or runs of the wires 28 and 29 is preferably an even number for providing maximum magnetic flux. Each of the pole plates 20 and 22 are provided with a transverse aper¬ ture 30 in its respective end portions. The diameter of t apertures is determined by the diameter of respective end portions of armatures 32 and 34 to be loosely surrounded a their respective end portions and to form a desired air ga between the periphery of each armature and the respective magnetic pole pieces described hereinbelόw. As shown by dotted lines (Fig. 3) , selected diagonally opposite corner portions 36 of the respective pole plates 20 and 22 are cu

away for the purposes of dividing the magnetic flux path to flow through the armatures 32 and 34 via pole pieces, as presently explained, and for reducing heat generated by mag¬ netic flux energizing the armatures. These pole plate cut off portions 36 are replaced by identically sized and shaped sections of nonmagnetic metal or material 38 (Fig. 2) rigid¬ ly joined to the respective pole plate to provide rigidity for the motor framework.

The pole plates form opposite poles, for example, the plate 20 forms a North pole and the pole plate 22 forms a South pole when energized by the coil 24. When positioned for assembling the framework 19, one of the pole plates is reversed end-to-end with respect to the other pole plate so that the nonmagnetic sections 38 confront magnetic material portions of the opposite pole plate (Fig. 4) .

Each of the pole plates 20 and 22 are provided with pairs of pole pieces, preferably rectangular in transverse section, normal to the plane of the respective plate and pro¬ ject toward the opposite plate. For example, one pair of pole pieces 40 are connected at one end to the magnetic ma¬ terial portion of the pole plate 20 adjacent and in diamet¬ ric opposition with respect to the aperture 30. Similarly, a second pair of pole pieces 42 are connected to the magnetic portion of the pole piece 20 adjacent and in diametric oppo- sition with respect to the aperture 31. Third and fourth pairs of magnetic pole pieces 44 and 46 are similarly con¬ nected to the magnetic portion of the pole plate 22 adjacent the respective aperture 31 and 30 with the pairs of pole pieces 40 and 46 disposed in 90° spaced relation with re- spect to the cooperating pairs of pole pieces 40 and 42 so that when the plates are disposed in framework assembled re¬ lation, as shown by Fig. 1, the respective pairs of pole pieces 40-44 and 42-46 form cooperating opposing polarity assemblies arranged in equally spaced circumferen ial rela- tion about the periphery of the respective armatures 32 and 34.

As is well known, when current flows through the coil wires 28 and 29, the coil core 26 forms a magnet having

OMPI /., WIFO

North and South poles at its respective ends according to the direction of current which magnetizes the respective pole plates 20 and 22. Assuming current flow in the wires 28 and 29, in the direction to generate North polarity in the pole plate 20, the magnetic force, represented by the vertical side face 47 of the coil core, as viewed in Fig. at its end portion contacting the pole plate 20, is induce into the end portion of the pole plate 20 having the aper¬ ture 31 therein. This force 47 is divided by the aperture 31 and enters the pair of pole pieces 42. The nonmagnetic material 38, at this end portion of the pole plate interru the magnetic flux path tending to surround the aperture 31 which, in addition to reducing heat during operation of th motor, directs the full magnetic flux to the pair of pole pieces 42 and builds up a magnetic field and e.m.f. on the windings of the rotor or armature 34. Similarly, the mag¬ netic force represented by the opposite vertical face 49 o the core, at its end in contact with the plate 20, magne -- izes the other end of the pole plate 20 containing the ape ture 30 so that the full magnetic flow is induced into the pair of pole pieces 40.

When the coil core 26 is in abutting relation with re spect to the other pole plate 22, the magnetic forces re¬ presented by the opposing vertical surfaces 47 and 49 of t coil core are similarly induced in the respective end por¬ tions of the pole plate 22. For example, the: force, repre sented by the coil core surface 47, moves into the left en portion of the pole plate 22, as viewed in Fig. 4, with th force being divided by the aperture 30 magnetizing the pai of pole pieces 46. Similarly, the coil core force indicat by the vertical surface 49 induces magnetic force in the other end of the pole plate 22 which is divided by the ape ture 31 and magnetizes the pair of pole pieces 44.

The length of each pole piece of the pairs .of pole pieces are less than the axial length of the coil 24 and i core 26 a distance equal to four times the air gap between the periphery of either armature and the adjacent surface the respective overlying pole pieces. The pole plates 20

and 22 are rigidly connected together during assembly of the motor framework by a plurality of nonmagnetic bolts or screws 50, one for each pole piece, projecting through the respec¬ tive pole plate and threadedly connected axially with the re- spective pole piece for the purpose of maintaining the respec¬ tive pole piece parallel with the axis of the respective arma¬ ture. A like plurality of nonmagnetic spacers 52 surround the respective screw 50 in the spacing between the respective pole piece and the adjacent pole plate. The framework 19 is rigidly secured to the housing as by bolting the pole plate 20 to the housing end wall 12 across a nonmagnetic spacer 53. The armatures 32 and 34, each have a shaft 54 and 56, respec¬ tively supported by a pair of bearings 58 and 60, respective¬ ly connected with the housing end walls 12 and 14. A pair of brush mounts 62' and 64, each containing a plurality, four in the example shown, of circumferentially spaced brushes 66, 67, 68 and 69, surround the commutator of the respective armature.

As illustrated by Fig. 5, the transverse width of the respective pole piece surface 70, facing the winding of the respective armature, is no greater than the transverse di¬ mension spanning any three segments 72 of a span seven arma¬ ture. This dimension is cooperatively related to the number of commutator segments spanned by the respective brush. Stated another way, the number of armature winding segments 72 transversely spanned by each pole piece is equal to the number of commutator segments spanned by the respective brush.

The magnetic flux between the pole pieces and armatures may be increased by enlarging the transverse dimension of the pole piece, as shown by Fig. 6, at 74. However, in this event opposing longitudinal edge portions of the pole piece

74 facing the armature are removed, as indicated by the re¬ cesses 76, so that the surface 78 of the pole piece 74 re¬ mains a transverse dimension equal with the dimension across any three armature winding segments 72 of a span seven arma ^ - ture.

As illustrated by Fig. 8, the coil forming wires 28-29 are connected in series with the wire 28 connected to the

positive terminal of a battery B and the wire 29 connected ground. The battery positive terminal is also connected i parallel to diametrically opposite brushes 66 and 67. The other two brushes 68 and 69 are connected to ground. As illustrated by Fig. 9, the coil wires 28 and 29 ma be connected in parallel to provide maximum torque for the motor. Obviously, substantially conventional switch means may be interposed in the wiring for selectively connecting the coil wires in series or in parallel for operating the motor in accordance with the load applied. Similarly, oth controls, not shown, may be incorporated to advance or re¬ tard the respective brush mounts for increasing or decreas the angular rate of rotation of the armatures.

Referring also to Fig. 7, the reference numerals 20' 22' indicate a pair of pole plates, each substantially cro shaped in general configuration which form a modified vers of the motor framework. The two pole plates 20' and 22' a each formed by integrally connecting a substantially squar section of plate metal 80-82 and 84-86 to the medial edge portion of the respective previously described pole plates 20 and 22. These pole plate extensions 80-82 and 84-86 ar similarly centrally bored for loosely surrounding respecti end portions of an additional pair of armatures, not shown, in the manner described hereinabove for the armatures 32 a 34. Similarly selected corner portions of the respective added plates 80-82 and 84-86 are cut away and replaced by identically shaped nonmagnetic metallic members 88-90 and 92-94 for the purposes of dividing the magnetic flux path, minimizing heat and providing support for magnetic pole pieces. Each of the added pole plate sections are similar provided with pairs of pole pieces 96-98 and 100-102 arran ed in similar diametric opposition about the respective ar ture receiving opening with one end of the respective pole piece projecting toward the opposite pole plate in interdi itated spaced relation thus forming a four-armature direct current motor energized by the coil 24.

The magnetic forces of the other surfaces of the coil core normal to its vertical surfaces 47 and 49 similarly a

divided and induced into the pairs of pole pieces 96-98 and 100-102 in the manner previously described for the forces indicated by the surfaces 47 and 49.

A motor formed in accordance with the drawings shown by Fig. 7 has particular application when used for powering a vehicle wherein two of the armatures may be employed for cruising speeds and a third or fourth armature energized by means of a magnetic clutch, not shown, for applying addition¬ al torque to the vehicle driving wheels as when accelerating or ascending a grade.

Referring now to Figs. 10 through 13, the numeral 110 indicates another embodiment of the motor having a housing

111 formed from nonmagnetic material comprising end plates

112 and 114, each centrally supporting bearings 116 and join- ed by side plates 120 and 122. The housing encompasses a generally cylindrical motor framework 123 including a pair of spaced-apart parallel generally circular magnetic material pole plates 124 and 126 normal to the longitudinal axis of the housing and having a coil 127 therebetween with its axis normal to the planes of the pole plates. The pole plate 124 is provided with a pair of diametrically opposite outstanding lugs integrally connected with a pair of equal length elon¬ gated parallel pole pieces 128 and 130 intermediate their ends. The pole pieces 128 and 130 are normal to the plane of the pole plate 124 and are connected at their respective ends with a pair of centrally apertured nonmagnetic discs 132 and 134 by nonmagnetic bolts or screws 136. The other pole plate 126 is similarly provided with a pair of outstand¬ ing lugs integrally connected with another pair of elongated parallel pole pieces 138 and 140 intermediate their ends with one of these pole pieces 138 and 140 connected with the disc 134 and their opposite ends projecting beyond the coil 127 and the other pole plate 124 and connected with the disc 132. The pole plate 126 is disposed so that its pole pieces 138 and 140 are spaced 90° ith respect to the pole pieces 128 and 130.

A pair of armatures 142 and 144 are disposed in axial alignment within the housing coaxial with the coil 127. A

peripheral portion of each armature 142 and 144 is disposed in close spaced relation with respect to the respective pairs of pole pieces 128-130 and 138-140. The transverse dimension of the surface of the respective pole piece facin the armature is limited to the ratio set forth hereinabove for the motor 10.

The disc apertures loosely surround the commutator end portion of the respective armature. A pair of brush holder 146 similarly provided with brushes surround the respective armature commutator between the housing ends and pole piece supporting discs 132 and 134, respectively. The respective armature shaft 148 and 150 form a drive shaft supported by the bearings 116 projecting beyond the housing ends 112 and 114. The other end of the armature shafts may be axially interconnected to form a single double armature motor or ma be journalled by bearings, not shown, supported by the pole plates 124 and 126 to form a dual motor.

As shown more clearly by Fig. 13, a peripheral portion of the respective pole plate is cut away to form diametric opposite recesses 152 to increase the spacing between ad¬ jacent surfaces of the pole pieces and the respective pole plate.

/,