WO2002052162A2 - Over-running clutch pulley with tool bores - Google Patents

Abstract

An over-running clutch pulley (10) for rotationally engaging an input device (12) and an output device (14), including a sheave member (20), a hub member (22), and a clutch member (26). The sheave member includes a sheave input section (28) adapted to engage the input device and a sheave clutch surface (30). The hub member, which is located substantially concentrically within the sheave member, includes a hub output section adapted to engage the output device and a hub clutch surface. The clutch member is adapted to engage the sheave clutch surface and the hub clutch surface upon the acceleration of the sheave member in a first rotational direction relative the hub member, and to disengage the sheave clutch surface and the hub clutch surface upon the deceleration of the sheave member in the first rotational direction. The hub member further includes a hub body section defining two tool bores (44, 46) formed to engage two projecting lugs of a tool.

Description

OVER-RUNNING CLUTCH PULLEY WITH TOOL BORES

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present this invention claims priority to U.S. provisional application

Serial No. 60/258,418, filed 27 December 2000, entitled "Over-Running Pulley Face Seal and Spanner Mounting Method".

TECHINCAL FIELD [0002] This invention relates generally to devices in the over-running clutch field, and more specifically to an improved over-running clutch pulley for use with an accessory device driven by an automotive engine with a belt drive.

BACKGROUND [0003] 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").

[0004] 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.

[0005] 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 "back 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.

[0006] 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. [0007] 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.

[0008] Based on the desire to manufacture and sell more fuel-efficient vehicles and maximize interior volume, automotive manufactures are designing vehicles with compact engine compartments. Because of this constraint, there is a need in the automotive field, if not in other fields, to create an over-running clutch pulley with a minimized length and weight, while maintaining or increasing the ease of installation.

BRIEF DESCRIPTION OF THE FIGURES [0009] FIGURE 1 is a perspective view of an over-running clutch pulley of the first preferred embodiment, shown with a drive belt as the input device and a cylindrical shaft as the output device;

[0010] FIGURE 2A is a partial cross-section view taken along the line 2-2 of the over-running clutch pulley of FIGURE 1; [0011] FIGURE 2B is a partial cross-section view of an over-running clutch pulley of the second preferred embodiment;

[0012] FIGURE 3 is a front view of the hub member of the over-running clutch pulley of FIGURE 1;

[0013] FIGURES 4 - 6 are perspective views of the over-running clutch pulley of FIGURE 1 and the preferred tools used to install the over-running clutch pulley of

FIGURE 1;

[0014] FIGURE 7 is a front view of the hub member of an over-running clutch pulley of the third preferred embodiment; and

[0015] FIGURE 8 is a front view of the hub member of an over-running clutch pulley of the fourth preferred embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0016] The following description of the four preferred embodiments of the invention is not intended to limit the scope of this invention to these four preferred embodiments, but rather to enable any person skilled in the art of over-running clutches to make and use this invention.

[0017] As shown in FIGURE 1 , the invention includes an over-running clutch pulley 10 for rotationally engaging 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.

[0018] As shown in FIGURE 2A, the over-running clutch pulley 10 of the first preferred embodiment includes a sheave member 20, a hub member 22 located substantially concentrically within the sheave member 20, 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 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 36 adapted to engage the output device and a hub clutch section 38 defining a hub clutch surface 40. The hub member further includes a hub body section 42 defining two tool bores 44 and 46 formed to engage a tool (shown in FIGURES 4 -6 and discussed below). The two tool bores 44 and 46 ease the installation and removal of the over-running clutch pulley 10, while minimizing overall length and weight of the over-running clutch pulley 10.

[0019] The sheave input section 28 of the sheave member 20 of the first preferred embodiment 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 50 with two sheave input shoulders 52 and at least one sheave input groove 54. 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 50 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.

[0020] The hub output section 36 of the hub member 22 of the first preferred embodiment functions to engage the cylindrical shaft. The hub output section 36 preferably defines a hub output surface 56 with a smooth section 58 and a threaded section 60, which functions to substantially prevent rotation and to axially retain the hub member 22 to the cylindrical shaft. Of course, the hub output section 36 may include other suitable devices or define other surfaces to prevent rotational and axial slippage and to engage the cylindrical shaft. The hub output surface 56 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 36 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.

[0021] As shown in FIGURE 2B, the over-running clutch pulley 10' of the second preferred embodiment includes a modified arrangement of the hub output surface 56' with the smooth section 58' located axially inward and the threaded section 60' is located axially outward. With this arrangement, the tool bores 44 and 46 are located directly radially outward of the threaded section. In all other aspects, the over-running clutch pulley of the second preferred embodiment is substantially similar to the over-running clutch pulley of the first preferred embodiment. [0022] The sheave clutch section 30 and the hub clutch section 38 of the first preferred embodiment, as shown in FIGURE 2A, function to provide the sheave clutch surface 32 and the hub clutch surface 40, 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 38 preferably extends radially outward from and axially over the hub body section 42. In this manner, the hub clutch section 38 is preferably made from the same material and with the same methods as the hub body section 42, but may alternatively be made from other suitable materials and with other suitable methods.

[0023] In the first preferred embodiment, the sheave clutch surface 32 and the hub clutch surface 40 are located substantially adjacent with an axial gap 64 between each other. The sheave clutch surface 32 and the hub clutch surface 40 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 40 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 40 may alternatively have differences with each other on these, or other, design specifications.

[0024] In the first preferred embodiment, the over-running clutch pulley 10 also includes a bearing member 66, which is preferably located between the sheave member 20 and the hub member 22. The bearing member 66 preferably functions to allow relative rotational movement of the sheave member 20 and the hub member 22. The bearing member 66, which is preferably a rolling element type, preferably includes an outer race element 68 preferably press-fit mounted on the sheave member 20, an inner race element 70 preferably press-fit mounted on the hub member 22, and ball bearing elements 72 preferably located between the outer race element 68 and the inner race element 70. The bearing member 66 may alternatively be of other suitable types, such as a journal bearing or a roller bearing. The bearing member 66 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. [0025] The clutch member 26 of the first preferred embodiment functions to engage the sheave clutch surface 32 and the hub clutch surface 40 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 40 upon the deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22. In the preferred embodiment, the clutch member 26 is a coil spring 76. The coil spring 76, which is made from conventional materials and with conventional methods, accomplishes the above features by the particular size and orientation of the coil spring 76. In alternative embodiments, the clutch member 26 may include other suitable devices that accomplish the above features.

[0026] The coil spring 76 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 40. Thus, when experiencing no rotational movement of the sheave member 20 or the hub member 22, the coil spring 76 frictionally engages with and exerts an outward force on both the sheave clutch surface 32 and the hub clutch surface 40. Further, the coil spring 76 is preferably oriented such that the coils extend axially in the first rotational direction from the sheave clutch surface 32 to the hub clutch surface 40. 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 clutch member 26. 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 76 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 76.

[0027] The unwinding of the coil spring 76 tends to increase the outward force of the coil spring 76 on the sheave clutch surface 32 and the hub clutch surface 40, 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 76 tends to decrease the outward force of the coil spring 76 on the sheave clutch surface 32 and the hub clutch surface 40, 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.

[0028] As shown in FIGURES 2 and 3, the hub body section 42 of the first preferred embodiment defines a hub front face 78, which faces axially outward after installation of the over-running clutch pulley 10 onto the output shaft. The tool bores 44 and 46 preferably extend axially inward toward the alternator of the vehicle from the hub front face 78, such that the tool bores 44 and 46 are accessible. The tool bores 44 and 46 are also preferably located radially inward from the sheave clutch surface 32 and the hub clutch surface 40, and radially outward from the hub output surface 56. Although the tool bores 44 and 46 are preferably diametrically opposed about the hub output surface 56, the tool bores 44 and 46 may alternatively be located in any suitable location radially outward from the hub output surface 56. Further, in an alternative embodiment, the hub front face 78 may define more than two tool bores located radially outward from the hub output surface 56. [0029] As shown in FIGURE 4, the tool bores 44 and 46 are formed to engage two projecting lugs 80 and 82 of a first tool 84. When the projecting lugs 80 and 82 are inserted into the tool bores 44 and 46, the first tool 84 may be pivoted to rotational drive the hub member 22 onto the externally threaded output shaft, thereby installing the over-running clutch pulley 10 to the alternator. Preferably, the first tool 84 is a conventional spanner wrench 86, which includes a clearance bore 88.

[0030] As shown in FIGURES 4 - 6, the clearance bore 88 of the spanner wrench 86 allows a second tool 90 to be passed through the spanner wrench 86. Preferably, the second tool 90 is a double-female socket 92 that engages a ratchet (not shown) at one end 94 and engages a double-male socket 96 at the other end

98. The double-male socket 96 is preferably shaped to engage a complementary female surface of the output shaft. In this manner, the second tool 90 may be inserted radially inward of the hub output surface and coupled to the output shaft. To install or remove the over-running clutch pulley 10 from the output shaft, the first tool 84 and the second tool 90 may be pivoted relative to each other. Preferably, the output shaft is held with the second tool 90, while the hub member 22 is tightened onto the output shaft with the first tool 84.

[0031] As shown in FIGURE 7, the over-running clutch pulley of the third preferred embodiment includes modified tool bores 44' and 46', which extend axially inward from the hub front face 78' and extend to the hub output surface 56. Preferably, the tool bores 44' and 46' and drilled into the hub body section 42' and then the hub output surface 56 is machined until the tool bores 44' and 46' adopt a semi-circular shape. The tool bores 44' and 46' preferably engage two projecting lugs of a modified first tool (not shown) and allow driving of the hub member 22' by the modified first tool.

[0032] As shown in FIGURE 8, the over-running clutch pulley of the fourth preferred embodiment includes a modified hub front face 78" with multiple serrations

99. The serrations 99 preferably frictionally engage a first tool (not shown) and allow driving of the hub member 22" by the first tool. To maximize friction during the driving of the hub member 22", the serrations 99 are preferably located along a radial pattern, but may alternatively be located in any suitable location. Preferably the serrations are elongated indentations, but may alternatively be small raised bumps or other friction-enhancing surface treatments.

[0033] 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 embodiments of the invention without departing from the scope of this invention defined in the following claims.

Claims

1. An over-running clutch pulley for rotationally engaging an input device and an output device, comprising: a sheave member including a sheave input section adapted to engage the input device and a sheave clutch section defining a sheave clutch surface; a hub member located substantially concentrically within said sheave member and including a hub output section adapted to engage the output device and a hub clutch section defining a hub clutch surface; and a clutch member adapted to engage said sheave clutch surface and said hub clutch surface upon the acceleration of said sheave member in a first rotational direction relative said hub member, and to disengage said sheave clutch surface and said hub clutch surface upon the deceleration of said sheave member in the first rotational direction relative said hub member; wherein said hub member further includes a hub body section defining two tool bores formed to engage two projecting lugs of a first tool and to allow driving of said hub member by the first tool.

2. The over-running clutch pulley of Claim 1 wherein said sheave clutch section extends radially inward from said sheave input section and wherein said hub clutch section extends radially outward from and axially over said hub output section.

3. The over-running clutch pulley of Claim 2 wherein said hub clutch surface is substantially adjacent said sheave clutch surface.

4. The over-running clutch pulley of Claim 1 wherein said sheave clutch surface is inwardly directed and substantially cylindrically shaped, and wherein said hub clutch surface is inwardly directed and substantially cylindrically shaped.

5. The over-running clutch pulley of Claim 1 further comprising a bearing member located between said sheave member and said hub member and adapted to allow relative rotational movement of said sheave member and said hub member.

6. The over-running clutch pulley of Claim 1 wherein said tool bores are both located radically inward from said sheave clutch surface and said hub clutch surface.

7. The over-running clutch pulley of Claim 1 wherein said hub body section defines a hub front face and wherein said tool bores extend axially inward from said hub front face.

8. The over-running clutch pulley of Claim 1 wherein said tool bores extend radially inward to said hub output surface.

9. The over-running clutch pulley of Claim 1 wherein said tool bores are both located radially outward from said hub output surface such that a second tool may be inserted radially inward of the hub output surface and coupled to the output device, and the first tool and the second tool may be pitoved relative to each other to install said over-running clutch pulley onto the output device.

10. The over-running clutch pulley of Claim 9 wherein said hub clutch surface includes a threaded section and wherein said tool bores are located directly radially outward of the threaded section.

11. An over-running clutch pulley for rotationally engaging an input device and an output device, comprising: a sheave member including a sheave input section adapted to engage the input device and a sheave clutch section defining a sheave clutch surface; a hub member located substantially concentrically within said sheave member and including a hub output section adapted to engage the output device and a hub clutch section defining a hub clutch surface; and a clutch member adapted to engage said sheave clutch surface and said hub clutch surface upon the acceleration of said sheave member in a first rotational direction relative said hub member, and to disengage said sheave clutch surface and said hub clutch surface upon the deceleration of said sheave member in the first rotational direction relative said hub member; wherein said hub member further includes a hub body section defining serrations formed to frictionally engage a first tool and to allow driving of said hub member by the first tool.