BACKGROUND During the operation of an automotive engine, a drive belt is typically used to power and operate various accessory devices. One of these accessory devices is typically an automotive alternator, which provides electrical power to the automobile. While several arrangements of drive belts are in use, the serpentine arrangement, which drives several accessory devices, is currently most favored. Serpentine arrangements typically include a drive pulley connected to the crankshaft of the engine (the"output device") and a drive belt trained about the drive pulley.

The drive belt is also trained about one or more conventional driven pulleys, which are connected to the input shafts of various accessories devices (the"input device").

Most conventional driven pulleys are made from a one-piece design with no over- running capabilities. In other words, the conventional driven pulleys are rigidly mounted to the input shaft and are incapable of allowing relative rotational movement between any section of the driven pulley and the input shaft. As a result of the lack of any over-running capabilities and of the generation of significant inertia by the accessory, relative slippage between the drive belt and the driven pulley may occur if the drive belt suddenly decelerates relative to the input shaft.

The relative slippage may cause an audible squeal, which is annoying from an auditory standpoint, and an undue wear on the drive belt, which is undesirable from a mechanical standpoint.

In a typical driving situation, the drive belt may experience many instances of sudden deceleration relative to the input shaft. This situation may occur, for example, during a typical shift from first gear to second gear under wide open throttle acceleration. This situation is worsened if the throttle is closed or"backed off"immediately after the shift. In these situations, the drive belt decelerates very quickly while the driven pulley, with the high inertia from the accessory device, maintains a high rotational speed, despite the friction between the drive belt and the driven pulley.

In addition to the instances of sudden deceleration, the drive belt may experiences other situations that cause audible vibration and undue wear. As an example, a serpentine arrangement with conventional driven pulleys may be used with an automobile engine that has an extremely low idle engine speed (which may increase fuel economy). In these situations, the arrangement typically experiences"belt flap"of the drive belt as the periodic cylinder firing of the automotive engine causes the arrangement to resonate within a natural frequency and cause an audible vibration and an undue wear on the drive belt.

The disadvantage of the conventional driven pulleys, namely the audible squeal, the undue wear, and the vibration of the drive belt, may be avoided by the use of an over-running clutch pulley instead of the conventional driven pulley. An over-running clutch pulley allows the pulley to continue to rotate at the same rotational speed and in a same rotational direction after a sudden deceleration of the drive belt. In a way, the over-running clutch pulley functions like the rear hub of a typical bicycle; the rear hub and rear wheel of a conventional bicycle continue to rotate at the same rotational speed and in the same rotational direction even after a sudden deceleration of the pedals and crankshaft of the bicycle. An example of an over-running clutch pulley is described in U. S. Patent No. 5,598,913 issued to the same assignee of this invention and hereby incorporated in its entirety by this reference.

Since many customers of new automobiles are demanding longer lives, with relatively fewer repairs, for their new automobiles, there is a need in the automotive field, if not in other fields, to create an over-running clutch pulley with increased wear resistance. This invention provides an improved method of manufacturing an over-running clutch pulley that includes features intended to increase structural rigidity of the over-running clutch pulley, while minimizing the cost and weight of the over-running clutch pulley.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an over-running clutch pulley made with the preferred methods of the invention, shown with a drive belt as the input device and a cylindrical shaft as the output device; FIG. 2 is a partial cross-section view, taken along the line 2-2 of FIG. 1, of the over- running clutch pulley made with the first preferred method; FIG. s 3A and 3B are partial cross-section views of the hub member involved in two variations of the first preferred method; FIG. 4 is a cross-section view of a hub crimp tool, a hub support member, and an over- running clutch pulley involved in the first preferred method; FIG. 5 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley made with the second preferred method; FIG. s 6A and 6B are partial cross-section views of the sheave member involved in two variations of the second preferred method; FIG. 7 is a cross-section view of a sheave crimp tool, a sheave support member, and an over-running clutch pulley involved in the second preferred method; FIG. 8 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley made with the third preferred method; FIG. 9 is a cross-section view of a hub crimp tool, a sheave crimp tool, a hub support member, a sheave support member, and an over-running clutch pulley involved in the third preferred method; and FIG. 10 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley made with the fourth preferred method.

DETAILED DESCRIPTION OF THE PREFERRED METHODS The following description of four preferred methods of the invention is not intended to limit the scope of this invention to these preferred methods, but rather to enable any person skilled in the art of over-running clutches to make and use this invention.

As shown in FIG. 1, an over-running clutch pulley 10 made with the preferred methods of the invention rotationally engages an input device 12 and an output device 14. The over-running clutch pulley 10 has been designed for use with a drive belt 16 as the input device 12, and with a cylindrical shaft 18 as the output device 14. More specifically, the over-running clutch pulley 10 has been particularly designed for use with a drive belt 16 with a grooved surface and a cylindrical shaft 18 of an automotive alternator. The over-running clutch pulley 10 may be used, however, in other environments, with other suitable input devices, such as smooth belt, a toothed belt, a V-shaped belt, or even a toothed gear, and with other suitable output devices, such as a polygonal shaft. Furthermore, the over-running clutch pulley 10 may be used in an environment with two devices that alternate their rotational input responsibilities, and in an environment with an"output device"that actually provides rotational input and with an"input device"that actually receives rotational input. In these alternative embodiments, the terms"input device"and"output device"are interchangeable.

As shown in FIG. 2, the over-running clutch pulley 10 made with the first preferred method includes a sheave member 20, a hub member 22 located substantially concentrically within the sheave member 20, a bearing member 24 located between the sheave member 20 and the hub member 22, and a clutch member 26, which cooperate to rotationally engage the drive belt and the cylindrical shaft. The sheave member 20 preferably includes a sheave input section 28 adapted to the engage the input device, and a sheave clutch section 30 defining a sheave clutch surface 32. Similarly, the hub member 22 preferably includes a hub output section 34 adapted to engage the output device, and a hub clutch section 36 defining a hub clutch surface 38. The hub member 22 also preferably includes a hub deformable section 40 defining a hub deformable surface 42. The hub deformable surface 42 is preferably deformed and positioned to axially retain the bearing member 24 relative the hub member 22. The retaining of the bearing member 24 in this manner improves structural rigidity of the over- running clutch pulley, while minimizing cost and weight of the over-running clutch pulley.

The sheave input section 28 of the sheave member 20 involved in the first preferred method functions to engage the drive belt. To substantially prevent rotational and axial slippage of the sheave member 20 and the drive belt, the sheave input section 28 preferably defines a sheave input surface 44 with two sheave input shoulders 46 and at least one sheave input groove 48. The sheave input section 28 may alternatively define other suitable surfaces, such as toothed surfaces or ribbed surfaces, to engage the input device. The sheave input surface 44 is preferably outwardly directed (away from the rotational axis of the over-running clutch pulley 10) and is preferably substantially cylindrically shaped. The sheave input section 28 is preferably made from conventional structural materials, such as steel, and with conventional methods, but may alternatively be made from other suitable materials and from other suitable methods.

The hub output section 34 of the hub member 22 involved in the first preferred method functions to engage the cylindrical shaft. The hub output section 34 preferably defines a hub output surface 50 with a smooth section 52 (which functions to ease and center the assembly of the over-running clutch pulley 10 onto the cylindrical shaft), a threaded section 54 (which functions to substantially prevent rotation and to axially retain the hub member 22 to the cylindrical shaft), and a hexagonal section 56 (which functions to mate with an allen wrench for easy tightening and loosening of the over-running clutch pulley 10 onto and off of the cylindrical shaft). Of course, the hub output section 34 may include other suitable devices or define other surfaces to prevent rotational and axial slippage, to engage the cylindrical shaft, and to engage a tool for tightening or loosening the over-running clutch pulley 10 onto and off of the cylindrical shaft. The hub output surface 50 is preferably inwardly directed (toward the rotational axis of the over-running clutch pulley 10) and is preferably substantially cylindrically shaped. The hub output section 34 is preferably made from conventional structural materials, such as steel, and with conventional methods, but may alternatively be made from other suitable materials and from other suitable methods.

The bearing member 24 involved in the first preferred method functions to allow relative rotational movement of the sheave member 20 and the hub member 22. The bearing member 24, which is preferably a rolling element type, preferably includes an outer race element 58 preferably press-fit mounted on the sheave member 20, an inner race element 60 preferably press-fit mounted on the hub member 22, ball bearing elements 62 preferably located between the outer race element 58 and the inner race element 60, and bearing seals 64 preferably extending between the outer race element 58 and the inner race element 60 on either side of the ball bearing elements 62. The bearing member 24 may alternatively be of other suitable types, such as a journal bearing or a roller bearing, may alternatively include other suitable elements, and may alternatively be mounted in other suitable manners. The bearing member 24 is a conventional device and, as such, is preferably made from conventional materials and with conventional methods, but may alternatively be made from other suitable materials and with other suitable methods.

The sheave clutch section 30 of the sheave member 20 and the hub clutch section 36 of the hub member 22 involved in the first preferred method function to provide the sheave clutch surface 32 and the hub clutch surface 38, respectively, for the engagement with the clutch member 26. The sheave clutch section 30 preferably extends radially inward from the sheave member 20. In this manner, the sheave clutch section 30 is preferably made from the same material and with the same methods as the sheave input section 28, but may alternatively be made from other suitable materials and with other suitable methods. The hub clutch section 36 preferably extends radially outward from and axially over the hub output section 34. In this manner, the hub clutch section 36 is preferably made from the same material and with the same methods as the hub output section 34, but may alternatively be made from other suitable materials and with other suitable methods. The hub clutch section 36 preferably partially defines a closed clutch cavity 66 to contain the clutch member 26.

In the over-running clutch pulley made with the first preferred method, the sheave clutch surface 32 and the hub clutch surface 38 are located substantially adjacent with an axial gap 68 between each other. The sheave clutch surface 32 and the hub clutch surface 38 are preferably inwardly directed (toward the rotational axis of the over-running clutch pulley 10) and are preferably substantially cylindrically shaped. Furthermore, the sheave clutch surface 32 and the hub clutch surface 38 preferably have a similar radial diameter, a similar axial length, and a similar smooth finish. These features allow optimum performance of the clutch member 26. The sheave clutch surface 32 and the hub clutch surface 38 may alternatively have differences with each other on these, or other, design specifications.

The clutch member 26 involved in the first preferred method functions to engage the sheave clutch surface 32 and the hub clutch surface 38 upon the acceleration of the sheave member 20 in a first rotational direction relative to the hub member 22, and to disengage the sheave clutch surface 32 and the hub clutch surface 38 upon the deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22. In the first preferred method, the clutch member 26 involves a coil spring 70. The coil spring 70, which is made from conventional materials and with conventional methods, accomplishes the above features by the particular size and orientation of the coil spring 70 within the closed clutch cavity 66. In alternative methods, the clutch member 26 may involve other suitable devices that accomplish the above features.

The coil spring 70 is preferably designed with a relaxed spring radial diameter that is sized slightly greater than an inner diameter of the sheave clutch surface 32 and the hub clutch surface 38. Thus, when inserted into the closed clutch cavity 66 and when experiencing no rotational movement of the sheave member 20 or the hub member 22, the coil spring 70 frictionally engages with and exerts an outward force on both the sheave clutch surface 32 and the hub clutch surface 38. Further, the coil spring 70 is preferably oriented within the closed clutch cavity 66 such that the coils extend axially in the first rotational direction from the sheave clutch surface 32 to the hub clutch surface 38. With this orientation, relative rotational movement of the sheave member 20 and the hub member 22 will result in an unwinding or winding of the spring member. In other words, acceleration of the sheave member 20 in the first rotational direction relative to the hub member 22 will bias an unwinding of the coil spring 70 and deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22 will bias a winding of the coil spring 70.

The unwinding of the coil spring 70 tends to increase the outward force of the coil spring 70 on the sheave clutch surface 32 and the hub clutch surface 38, thereby providing engagement, or"lock", of the sheave member 20 and the hub member 22. This engagement condition preferably occurs upon the acceleration of the sheave member 20 in the first rotational direction relative to the hub member 22. On the other hand, the winding of the coil spring 70 tends to decrease the outward force of the coil spring 70 on the sheave clutch surface 32 and the hub clutch surface 38, thereby allowing disengagement, or"slip", of the sheave member 20 and the hub member 22. This disengagement condition preferably occurs upon the deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22.

During the"slip"condition of the over-running clutch pulley 10, the coil spring 70 will lightly rub across the sheave clutch surface 32 or the hub clutch surface 38, which may cause wear of these surfaces. Similarly, during the"lock"condition of the over-running clutch pulley 10, the coil spring 70 will forcefully engage with the sheave clutch surface 32 and the hub clutch surface 38, which may also cause wear of these surfaces. To resist the wear of these surfaces, the sheave clutch surface 32 and the hub clutch surface 38 are preferably formed or treated to have a relatively high surface hardness.

In contrast to the sheave clutch surface 32 and the hub clutch surface 38, the hub deformable surface 42 involved in the first preferred method preferably has a relatively low surface hardness to facilitate the deformation and positioning of the hub deformable section 40 to axially retain the bearing member 24 relative the hub member 22. Providing the hub clutch surface 38 with a greater surface hardness than the hub deformable surface 42 may be accomplished with several suitable methods.

In the first variation of the first preferred method, as shown in FIG. 3A, the hub member 22 is preferably provided with a hub removable surface 72, the hub clutch surface 38 and the hub removable surface 72 are preferably treated, and the hub removable surface 72 is preferably later removed. Providing the hub removable surface 72 functions to shield the hub deformable surface 42 from the heat treatment. For this reason, the hub removable surface 72 is preferably located substantially over the hub deformable surface 42. Treating the hub clutch surface 38 and the hub removable surface 72 functions to increase the surface hardness of the hub clutch surface 38. The treatment preferably includes diffusing nitrogen and carbon into the surfaces, including the hub clutch surface 38 and the hub removable surface 72, of the hub member 22. This preferred action, commonly known as carbonitriding, is well known in the metallurgical field and is similar to carburizing, except for a small addition of nitrogen in the atmosphere and a small reduction in temperature. The treatment may alternatively include other suitable actions, either in combination with or as substitution for the preferred actions. These other suitable actions may include carburizing, induction heat treatment, radiant heat treatment, laser cladding, and chemical or electroplating deposition. Finally, removing the hub removable surface 72 functions to expose the hub deformable section 40. The removal preferably includes machining of the hub removable section, but the removal may include other suitable actions, either in combination with or as substitution for the preferred actions.

In the second variation of the first preferred method, as shown in FIG. 3B, the hub clutch section 36B and the hub deformable section 40B of the hub member 22B are preferably separately formed, the hub clutch section 36B is preferably treated, and the hub clutch section 36B and the hub deformable section 40B are preferably later coupled. Separately forming the hub clutch section 36B and the hub deformable section 40B functions to allow separate treatment of the hub clutch section 36B, which increases the surface hardness of the hub clutch surface 38B but not the hub deformable section 40B. The treatment preferably includes the same actions as described in the first preferred method, but may alternatively include other suitable actions, either in combination with or as substitution for the preferred actions. Coupling the hub clutch section 36B and the hub deformable section 40B functions to provide the hub member 22B as one piece. The coupling preferably includes connecting the hub clutch section 36B and the hub deformable section 40B with a press fit or other suitable mechanical fastener, but may alternatively include other suitable devices or methods.

As shown in FIG. 4, in the first preferred method, the sheave member 20, the hub member 22, the clutch member 26, and the bearing member 24 are each provided; the hub member 22 is positioned within the sheave member 20; the clutch member 26 is positioned near the sheave clutch surface 32 and the hub clutch surface 38; and the bearing member 24 is positioned between the sheave member 20 and the hub member 22. At this point, the near- assembled pulley 74 is preferably positioned on a hub support member 76and a hub crimp tool 78 is lowered with a sufficient force to deform the hub deformable surface 42. The hub support member 76 preferably functions to provide support for the near-assembled pulley 74 during the engagement of the hub crimp tool 78 with the near-assembled pulley 74. For this reason, the hub support member 76 is preferably made from a structural material and is preferably formed with a suitable shape. The hub crimp tool 78 functions to deform and position the hub deformable surface 42. For this reason, the hub crimp tool 78 is preferably made from a structural material and is preferably formed with a suitable shape. The use of the hub support member 76 and the hub crimp tool 78 provides the over-running clutch pulley with the hub deformable surface 42 that is deformed and positioned to axially retain the bearing member 24.

In alternative embodiments, the deforming act may be accomplished with other suitable devices and methods.

As shown in FIG. 5, the sheave member 20 of the second preferred method includes a sheave deformable section 40'defining a sheave deformable surface 42'. The sheave deformable surface 42'is preferably deformed and positioned to axially retain the bearing member 24 relative the sheave member 20. The retaining of the bearing member 24 in this manner improves structural rigidity of the over-running clutch pulley 10', while minimizing cost and weight of the over-running clutch pulley 10'. In all other respects, the over-running clutch pulley 10'made with the second preferred method is similar to the over-running clutch pulley 10 made with the first preferred method.

Like the hub deformable surface 42 of the first preferred embodiment, the sheave deformable surface 42'preferably has a relatively low surface hardness to facilitate the deformation and positioning of the sheave deformable section 40'to axially retain the bearing member 24 relative the sheave member 20. Providing the sheave clutch surface 32 with a greater surface hardness than the sheave deformable surface 42'may be accomplished with several suitable methods.

In the first variation of the second preferred method, as shown in FIG. 6A, the sheave member 20 is preferably provided with a sheave removable surface 72', the sheave clutch surface 32 and the sheave removable surface 72'are preferably treated, and the sheave removable surface 72'is preferably later removed. In all other respects, the first variation of the second preferred method is similar to the first variation of the first preferred method.

In the second variation of the first preferred method, as shown in FIG. 6B, the sheave clutch section 30B and the sheave deformable section 40B'of the sheave member 20B are preferably separately formed, the sheave clutch section 30B is preferably treated, and the sheave clutch section 30B and the sheave deformable section 40B'are preferably later coupled.

In all other respects, the second variation of the second preferred method is similar to the second variation of the first preferred method.

As shown in FIG. 7, the near-assembled pulley 74'of the second preferred embodiment is assembled in a similar manner as the near-assembled pulley 74 of the first preferred embodiment, except that the near-assembled pulley 74'is preferably positioned on a sheave support member 76'and a sheave crimp tool 78'is lowered with a sufficient force to deform the sheave deformable surface 42'.

As shown in FIG. 8, the over-running clutch pulley 10"made with the third preferred embodiment is a combination of the hub deformable surface 42'of the first preferred embodiment and the sheave deformable surface 42'of the second preferred embodiment. The hub deformable surface 42 and the sheave deformable surface 42'are both preferably deformed and positioned to axially retain the bearing member 24 relative the hub member 22 and the sheave member 20. The retaining of the bearing member 24 in this manner improves structural rigidity of the over-running clutch pulley, while minimizing cost and weight of the over- running clutch pulley. In all other respects, the over-running clutch pulley 10"made with the third preferred method is similar to the over-running clutch pulley 10 made with the first preferred method and the over-running clutch pulley 10'made with the second preferred method.

As shown in FIG. 9, the near-assembled pulley 74"of the third preferred embodiment is assembled in a similar manner as the near-assembled pulley 74 of the first preferred embodiment and the near-assembled pulley 74'of the second preferred embodiment, except that the near-assembled pulley 74"is preferably positioned on both the hub support member 76 and the sheave support member 76'. In the third preferred method, the hub crimp tool 78 is lowered with a sufficient force to deform the hub deformable surface 42 and then the sheave crimp tool 78'is lowered with a sufficient force to deform the sheave deformable surface 42'.

As shown in FIG. 10, the fourth preferred method of the invention involves the same elements of the first preferred embodiment (the sheave member 20, the hub member 22, the clutch member 26, and the bearing member 24), but the hub member 22 made with the third preferred method preferably does not include a hub deformable section or a hub deformable surface. Instead, the over-running clutch pulley 10"'made with the fourth preferred method preferably includes a sealing member 80 defining a seal deformable surface 82. The sealing member 80 functions to provide axially retention of the bearing member 24 and to substantially shield the bearing member 24. The sealing member 80 is preferably made from a conventional steel material and with conventional methods, but may alternatively be made from other suitable materials and with other suitable methods.

In the fourth preferred method, the sheave member 20, the hub member 22, the clutch member 26, the bearing member 24, and the sealing member 80 are each provided; the hub member 22 is positioned within the sheave member 20; the clutch member 26 is positioned near the sheave clutch surface 32 and the hub clutch surface 38; and the bearing member 24 is positioned between the sheave member 20 and the hub member 22. At this point, the sealing member 80 is crimped into the hub member 22. The crimping of the sealing member 80 deforms the seal deformable surface 82 into the hub member 22, positions the sealing member 80 to axially retain the bearing member 24, and preferably positions the sealing member 80 to substantially shield the bearing member 24. The crimping and positioning of the sealing member 80 is preferably accomplished with a conventional crimping device (not shown), but may be accomplished with any suitable device or method.

As any person skilled in the art of over-running clutches will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred methods of the invention without departing from the scope of this invention defined in the following claims.