Unbalanced drag operation of overrunning clutch

Abstract

The transmission system (10) includes a clutch assembly (20) having radially spaced input and output members (18, 26) and a cage (32) that retains the torque transmitting member (30) therebetween. Rotation of the input member relative to the output member in a first direction engages the clutch assembly, while rotation of the output member relative to the input member in the first direction disengages the clutch assembly. The clutch further includes a drag assembly (24) that includes a rotatable member (34) coupled to the cage (32) of the clutch assembly (20) and a fixed member (36). The rotatable member (34) rotates in a first direction relative to the fixed member, but rotation of the rotatable member (34) in a second direction relative to the fixed member (36) is restricted, thereby restricting rotation of the input member of the clutch assembly in the second direction.

Description

[Technical Field]

[0001] The present invention relates to a clutch, and more particularly to a clutch in which an input member of the clutch drives an output member of the clutch in a first direction, and when the output member overruns the input member in the first direction, it is free to rotate in a second direction relative to the input member, and further rotation of the input member in the second direction is prevented. [Background technology]

[0002] Clutches are used in many applications to selectively engage and disengage a driving device, such as a motor, with a driven device (e.g., one or more wheels) to transfer torque from the driving device to the driven device. Conventional clutches exist that allow torque transfer in one rotational direction (unidirectional) or both rotational directions (bidirectional), and also allow the normally driven member of the clutch attached to the driven device to overrun the driving member of the clutch attached to the driving device. However, conventional clutches are not capable of operating in all of the different modes required by a particular application. For example, in one particular application for an electric scooter, a clutch is desired that allows the driving member or input member of the clutch, i.e., the electric motor, to drive the driven member or output member of the clutch, i.e., the wheel, in a first forward direction, allowing the wheel to overrun the motor in the forward direction and also preventing reverse rotation of the motor while free-wheeling relative to the motor in a second, reverse direction.

[0003] The present inventors have identified a need for a clutch that minimizes and / or eliminates one or more of the above-identified deficiencies. Summary of the Invention [Means for solving the problem]

[0004] The present invention relates to a clutch, and more particularly to a clutch in which an input member of the clutch drives an output member of the clutch in a first direction, allowing the output member to overrun the input member in the first direction, freely rotate relative to the input member in a second direction, and prevent further rotation of the input member in the second direction.

[0005] A clutch according to one embodiment includes a clutch assembly including an input member disposed about a first axis of rotation and coupled to a driving device, an output member disposed about the first axis of rotation and coupled to a driven device, and multiple torque transmission members disposed between the input and output members. Rotation of the input member relative to the output member in a first rotational direction about the first axis of rotation engages the multiple torque transmission members with the output member. Rotation of the output member relative to the input member in the first rotational direction about the first axis of rotation disengages the multiple torque transmission members from the output member. The clutch assembly further includes a cage configured to hold the multiple torque transmission members and configured to rotate with the input member. The clutch further includes a drag assembly disposed about a second axis of rotation and including a rotatable member coupled to the cage of the clutch assembly for rotation with the cage. The drag assembly further includes a fixed member fixed against rotation about the second axis of rotation. The rotatable member rotates in a first rotational direction about the second axis relative to the fixed member, but rotation of the rotatable member is restricted relative to the fixed member about the second axis in a second rotational direction opposite the first rotational direction, thereby restricting rotation of the input member of the clutch assembly in the second rotational direction about the first axis.

[0006] Another embodiment of a clutch includes a clutch assembly including a first member disposed about a first axis of rotation, a second member disposed about the first axis of rotation and radially spaced from the first member, and a plurality of torque transmission members disposed between the first and second members. Rotation of the first member relative to the second member in a first rotational direction about the first axis of rotation engages the plurality of torque transmission members with the second member. Rotation of the second member relative to the first member in the first rotational direction about the first axis of rotation disengages the plurality of torque transmission members from the second member. The clutch assembly further includes a cage configured to retain the plurality of torque transmission members and configured to rotate with the first member. The clutch further includes a drag assembly disposed about a second axis of rotation and including a rotatable member coupled to the cage of the clutch assembly for rotation with the cage. The drag assembly further includes a fixed member fixed against rotation about the second axis of rotation. The rotatable member rotates in a first rotational direction about the second axis relative to the fixed member, but rotation of the rotatable member is restricted relative to the fixed member about the second axis in a second rotational direction opposite the first rotational direction, thereby restricting rotation of the input member of the clutch assembly in the second rotational direction about the first axis.

[0007] Clutches according to the present teachings offer improvements over conventional clutches, specifically, they allow a combination of operating modes in which a drive or input member of the clutch can drive a driven or output member of the clutch in a first direction, the driven or output member can overrun the drive or input member in the first direction, can rotate freely relative to the drive or input member in a second direction, and rotation of the drive or input member in the second direction is prevented.

[0008] The foregoing and other aspects, features, details, applications, and advantages of the present invention will become apparent from a reading of the following description and claims, and from a review of the accompanying drawings.

[0009]

[0010]

[0011]

[0012] [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a system incorporating a clutch according to the present teachings. [Figure 2] FIG. 1 is a perspective view of a clutch according to one embodiment of the present teachings. [Figure 3] FIG. 1 is a perspective view of a clutch according to one embodiment of the present teachings. [Figure 4] FIG. 4 is a perspective view of the clutch of FIGS. 2-3 with a portion of the clutch removed. [Figure 5] 5 is a cross-sectional view of the clutch of FIGS. 2-4 taken along line 5-5 of FIG. 2. [Figure 6] 6 is a cross-sectional view of the clutch of FIGS. 2-5 taken along line 6-6 of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring now to the drawings, wherein like reference numerals are used to identify identical components in various views, FIG. 1 illustrates a power generation and transmission system 10. The system 10 includes a drive device 12 for generating a force used to drive a driven device 14. The drive device 12 may comprise a conventional motor, including, for example, an electric motor, a hydraulic motor, or a wind motor. The device 12 may further include a conventional gearbox or reducer (which may be combined with the motor to form a conventional gear motor) for controlling the output speed and torque supplied to the driven device 14. The device 12 may output rotational torque via an output member 16, such as a shaft, or other rotating body, such as a gear, pulley, or sprocket. The driven device 14 may comprise, for example, one or more wheels for a transportation vehicle such as a scooter or cycle. It should be understood that the form of the device 14 depends on the application, and that the device 14 may comprise any of a wide variety of devices configured to receive input torque. The device 14 may input rotational torque via an input member 18, such as a shaft, or other rotating body, such as a gear, pulley, or sprocket. Although devices 12, 14 are labeled herein as "driving" and "driven" devices according to their primary modes of operation, it should be understood that under certain operating conditions, the direction of torque transfer through system 10 may be reversed, such that driven device 14 generates and outputs torque via member 18 and driving device 12 inputs torque via member 16. System 10 may further include a clutch 20 in accordance with the teachings disclosed herein. Clutch 20 selectively couples devices 12, 14 to transfer torque between devices 12, 14. Specifically, clutch 20 receives torque from output member 16 of device 12 and selectively transfers torque to input member 18 of device 14. As described above, clutch 20 may also receive torque from input member 18 of device 14 and selectively transfer torque to output member 16 of device 12 under certain conditions.It should be understood that the output member 16 may be formed within the device 12 or the clutch 20 , and similarly, the input member 18 may be formed within the device 14 or the clutch 20 .

[0015] 2-5, clutch 20 includes a clutch assembly 22 and a drag assembly 24. Clutch assembly 22 is provided to selectively transfer torque between driving device 12 and driven device 14. Referring to FIGS. 4-5, clutch assembly 22 includes an input member 26, an output member 28, a plurality of torque transmission members 30, and a cage 32. Drag assembly 24 provides various levels of drag to cage 32 of clutch assembly 22 to brake the elements of clutch assembly 22 and achieve specific operating modes of clutch 20. In the illustrated embodiment, assembly 24 includes a rotatable member 34, a fixed member 36, means for preventing rotation of fixed member 36, such as a ground frame 38, and means for transferring braking torque from fixed member 36 to rotatable member 34, such as a torque transmission member 40.

[0016] The input member 26 receives torque from the device 12 via the member 16 and selectively transfers the torque to the output member 28 via the torque transmission member 30. The member 26 may be disposed about and centered around a rotational axis 42. In the illustrated embodiment, the input member 26 is disposed radially inward of the output member 28. However, it should be understood that the relative positions of the input member 26 and the output member 28 may be reversed such that the input member 26 is disposed radially outward of the output member 28. With reference to FIG. 6 , the input member 26 may define a circular bore 44 that is annular in shape and configured to receive the member 16. The radially inner surface of the member 26 may further define a keyway 46 that communicates with the bore 44 and is configured to receive a key used to couple the input member 26 to the member 16 and rotates together with the key about the axis 42. However, it should be understood that the member 26 may be coupled to the member 16 in a variety of ways. The input member 26 defines a plurality of ramped surfaces 48, or cam surfaces, on its radially outer surface. Each torque transmitting member 30 moves along a corresponding ramped surface 48 on the input member 26 between an engaged position adjacent one end of the ramped surface 48, where the member 30 is clamped between and engages the members 26, 28 of the clutch assembly 22, and a disengaged position adjacent the other end of the ramped surface 48, where the member 30 is disengaged from the output member 28. Referring to FIG. 5 , the diameter of the member 26 may vary along the axial length of the member 26, and each ramped surface 48 may define a shoulder 50 at either axial end configured to limit movement of the member 30 along the axis 42 relative to the member 26.

[0017] The output member 28 transfers torque received from the input member 26 via the torque transmitting member 30 through the member 18 to the device 14. The output member 28 may be coupled to the member 18 in a variety of ways known in the art, depending on the configuration of the member 18. The output member 28 may be disposed about or centered on the axis 42. Again, in the illustrated embodiment, the output member 28 is disposed radially outward of the input member 26. However, it should be understood that the relative positions of the input member 26 and the output member 28 may be reversed such that the output member 28 is disposed radially inward of the input member 26. The output member 28 may be annular in shape and define a circular bore configured to accommodate the input member 26, the torque transmitting member 30, and the cage 32. A radially inner surface 52 of the member 28 faces the angled surface 48 on the input member 26 and defines an engagement surface for the torque transmitting member 30 during engagement of the clutch assembly 22.

[0018] Torque transmitting members 30 transfer torque from input member 26 to output member 28. In the illustrated embodiment, members 30 comprise rollers. However, it should be understood that members 30 may take any of a variety of forms common in the art, including, for example, pawls or chocks. Members 30 may be supported by cage 32 and equally spaced about axis 42 between members 26, 28. In the illustrated embodiment, each member 30 moves along a corresponding ramped surface 48 on input member 26 between an engaged position adjacent one end of ramped surface 48, where member 30 clips between and engages ramped surface 48 of member 26 and surface 52 of member 28, and a disengaged position adjacent the other end of ramped surface 48, where member 30 is disengaged from surface 52 of output member 28.

[0019] A cage 32 is provided to maintain the relative circumferential position and spacing of the torque transmitting members 30. According to one aspect of the clutch disclosed herein, to allow the output member 28 to freely rotate relative to the input member 26, the cage 32 is also provided to shift the members 30 between engaged and disengaged positions under certain operating conditions. Referring to FIG. 5 , the cage 32 is generally Z-shaped in cross section. Specifically, the cage 32 includes a pair of generally axially extending portions 54, 56 and a generally radially extending portion 58 extending between the portions 54, 56. The portion 54 extends between the input member 26 and the output member 28 of the clutch assembly 22 to position and space the torque transmitting members 30. Referring to FIG. 6 , the portion 54 engages a pair of spaced-apart circumferential portions of each roller 30. Due to the configuration of the input member 26, the torque transmitting member 30, and the cage 32, the cage 32 is configured to rotate with the input member 30 about the axis 42, but can be shifted circumferentially about the axis 42 relative to the input member 26 to move the torque transmitting member 30 between engaged and disengaged positions within the clutch assembly 22. Referring again to FIG. 5 , a portion 56 of the cage 32 extends at least partway through the drag assembly 24. In the illustrated embodiment, the portion 56 is disposed radially inward of the rotatable member 34. In accordance with one aspect of the clutch 20 disclosed herein, the cage 32 is coupled to the rotatable member 34 of the drag assembly 24 such that the input member 26 of the clutch assembly 22 and the rotatable member 34 of the drag assembly 24 are configured to rotate relative to one another. The cage 32 may be coupled to the rotatable member 34 in a variety of ways common in the art, including by fasteners such as welding or adhesives, or by complementary features including crimps, splines, keys and keyways, or interlocking projections. Portion 58 of cage 32 extends between and connects portions 54, 56. Portions 56, 58 together define a shoulder configured to receive and support drag assembly 24.

[0020] The rotatable member 34 of the drag assembly 24 is provided to transfer braking torque through the cage 32 and torque transmitting member 30 to the input member 26 of the clutch assembly 22 and prevent rotation of the input member 26 in one rotational direction about the axis 42. The rotatable member 34 may be disposed about and centered on a rotational axis 60. In the illustrated embodiment, the axis 60 coincides with the axis 42. The rotatable member 34 is annular in shape. An inner diameter of the member 34 may be sized to accommodate the portion 56 of the cage 32, and the member 34 may be supported on the portion 56 of the cage 32. The radially outer surface of the member 34 may define an inner race 62 for a bearing 64 disposed between the rotatable member 34 and the fixed member 36. Another portion of the radially outer surface of the member 34, axially spaced from the race 62, may define an engagement surface 66 for the torque transmitting member 40 during engagement of the drag assembly 24. In the illustrated embodiment, surface 66 is located closer to clutch assembly 24 than race 62, but it should be understood that the relative positions of race 62 and surface 66 (and thus bearing 64 and member 40) may be reversed.

[0021] The fixed member 36 transmits a braking torque to the rotatable member 34 (and ultimately to the input member 26 of the clutch assembly 22) to limit or prevent rotation of the rotatable member 34 (and the input member 26 of the clutch assembly 22) in one direction about the axis 60. The fixed member 36 may be disposed about or centered on the axis 60. The fixed member 36 is fixed against rotation about the axis 60 by a ground frame 38. The member 36 is annular in structure. A radially inner surface of the member 36 may define an outer race 68 for the bearing 64. Another portion of the radially outer surface, axially spaced from the race 68, may define an engagement surface 70 for the torque transmitting member 40 during engagement of the drag assembly 24. Again, in the illustrated embodiment, surface 70 is located closer to clutch assembly 24 than race 68, but it should be understood that the relative positions of race 68 and surface 70 (and thus bearing 64 and member 40) may be reversed. The outer diameter of member 36 is sized to be received within ground frame 38.

[0022] The ground frame 38 provides a means for preventing rotation of the fixed member 36. Referring to FIG. 4, the ground frame 38 includes a substantially circular body 71 and arms 72 projecting radially outward from the body 71. The arms 72 are configured to be attached to a rotationally fixed structure. The body 71 is configured to couple to the fixed member 36 of the drag assembly 24. Referring again to FIG. 5, the body 71 may be configured to surround the fixed member 36 and has an inner diameter sized to receive the fixed member 36 and engage the fixed member 36 with an interference fit. The inner diameter of the body 71 may vary to define a shoulder adjacent one axial end of the body 71, which is configured to engage the fixed member 36 of the drag assembly 24 and oppose a shoulder formed on the cage 32 and engage the rotatable member 34 of the drag assembly 24. It should be understood that the application of mechanical force to secure the member 36 against rotation and the configuration of the ground frame 38 are merely exemplary. The member 36 may be secured against rotation in a variety of ways. For example, electromagnetic forces, as opposed to mechanical forces, may be used to maintain the position of the fixed member 36. As opposed to a particular structure of the ground frame 38, a variety of different structures may be formed to couple the member 36 to the fixed structure and otherwise prevent rotation of the fixed member 36.

[0023] The torque transmitting members 40 transfer braking torque from the fixed member 36 to the rotatable member 34. The members 40 may comprise chocks. However, it should be understood that the members 40 may take any of a variety of forms common in the art, including, for example, pawls. The members 40 may be supported by a cage (not shown) and biased into position by springs (not shown) in a conventional manner. The members 40 may be equally spaced about the axis 60 between the members 34, 36. When the rotatable member 34 rotates about the axis 60 in one rotational direction, the members 40 assume a disengaged position in which they are disengaged from one or both of the surfaces 66, 70 of the rotatable member 34 and the fixed member 36, and no torque is transmitted between the rotatable member 34 and the fixed member 36. When the rotatable member 34 rotates in the counter-rotational direction about the axis 60, the member 40 moves from a disengaged position to an engaged position (e.g., as a result of centrifugal force), where the member 40 is clamped between and engages the surfaces 66, 70 of the rotatable member 34 and the fixed member 36, thereby transferring braking torque from the fixed member 36 to the rotatable member 34.

[0024] While a particular embodiment of drag assembly 24 in the form of a friction clutch has been described above, it should be understood that drag assembly 24 can be formed in a variety of different ways that permit a rotatable member, such as member 34, to rotate in one rotational direction (clockwise in the illustrated embodiment) about axis 60 relative to fixed member 36, and restrict rotatable member 34 from rotating in the opposite rotational direction (counterclockwise in the illustrated embodiment) about axis 60 relative to fixed member 36. Drag assembly 42 can be formed as a different type of clutch, for example, by varying the type of torque-transmitting member between rotatable member 34 and fixed member 36. Alternatively, drag assembly 24 can be formed as a braking system (e.g., having a rotatable disk (rotor) and a fixed disk (stator) selectively engaged by mechanical, fluid (pneumatic or hydraulic), or electromagnetic forces).

[0025] Clutch 20 has several different modes of operation. In one mode of operation, clutch 20 is configured to transfer torque from input member 26 of clutch assembly 22 to output member 28 of clutch assembly 22, causing output member 28 to rotate in a first rotational direction. With reference to FIG. 6 , in the illustrated embodiment, clockwise rotation of input member 26 relative to output member 28 causes torque-transmitting member 30 to move along ramped surface 48 from a disengaged position to an engaged position, where member 30 is clamped between input member 26 and output member 28 and engages corresponding surfaces (ramped surface 48 and surface 72) of input member 26 and output member 28. With reference again to FIG. 5 , torque is thus transferred from input member 26 to output member 28, causing output member 28 to rotate in a clockwise direction about axis 42. Cage 32 rotates clockwise with input member 26, causing corresponding rotation of rotatable member 48 in a clockwise direction about axis 60. The drag assembly 24 is configured to permit rotation of the rotatable member 34 in a clockwise direction. Thus, the torque transmission member 40 does not engage at least one of the rotatable member 34 and the fixed member 36, and the rotatable member 34 assumes a disengaged position in which it is able to rotate relative to the fixed member 36. The mass of the rotatable member 34 applies a relatively small amount of drag to the cage 32.

[0026] In another mode of operation, the clutch 20 is configured to operate as an overrunning clutch in one rotational direction. As described above, when the input member 26 of the clutch assembly 22 rotates clockwise relative to the output member 28 of the clutch assembly 22, the clutch assembly 22 engages the output member 28 and drives the output member 28 in the same direction and at the same speed as the input member 26. However, if a greater torque is applied to the output member 28, such that the output member rotates clockwise about the axis 42 at a greater speed relative to the input member 26, the torque transmitting member 30 will move along the ramped surface 48 on the input member 26 from an engaged position to a disengaged position where the member 30 is no longer clamped between the input member 26 and the output member 28 and engages the surface 52 of the output member 28. Thus, if the output member 28 rotates clockwise at a greater speed than the input member 26, the output member 28 can overrun the input member 26.

[0027] In another mode of operation, the clutch 20 disengages the clutch assembly 22 when the input member 26 of the clutch assembly 22 is driven in a clockwise direction by the driving device 12, but the output member is driven in a counterclockwise direction by the driven device 14 with a greater torque, thereby allowing the output member 28 to freely rotate in the counterclockwise direction relative to the input member 26. Relative rotation of the input member 26 and the output member 28, with the input member 26 rotating in a clockwise direction and the output member 28 rotating in a counterclockwise direction, initially results in engagement of the clutch assembly 22, as described above. However, if a greater torque is applied to the output member 28 than to the input member 26, it will overcome the torque applied to the input member 26 in the clockwise direction, and the torque transmitting member 30, cage 32, and input member 26 will be driven in a counterclockwise direction about axis 42. Rotation of the cage 32 in the counterclockwise direction causes limited rotation of the rotatable member 34 of the drag assembly 24 in the counterclockwise direction about axis 60. Counterclockwise rotation of the rotatable member 34 relative to the fixed member 36 of the drag assembly 24 moves the torque transmitting member 40 of the drag assembly 24 from a disengaged position to an engaged position, where the member 40 is pinned between surfaces 66, 70 of the rotatable member 34 and the fixed member 36. Because the fixed member 36 is secured against rotation via the grounding frame 38, a braking torque is applied to the rotatable member 34 via the torque transmitting member 40, preventing further rotation of the rotatable member 34. Because the cage 32 is coupled to the rotatable member 34, further rotation of the cage 32 about the axis 42 is also prevented. The cage 32 applies a force to the torque transmitting member 30 in the clutch assembly 22, moving the member 30 along the ramped surface 48 from an engaged position between the input member 26 and the output member 28 to a disengaged position. After disengagement of clutch assembly 22 , output member 28 may rotate or free-rotate around input member 26 in a counterclockwise direction about axis 42 .Continued application of clockwise torque to the input member 26 will resume clockwise rotation of the input member 26 along with corresponding rotation of the torque transmission member 30, cage 32, and rotatable member 34 of the drag assembly 24, thereby disengaging the drag assembly 24.

[0028] In another mode of operation, when the input member 26 is driven in the opposite rotational direction (counterclockwise in the illustrated embodiment), the clutch 20 is configured to operate as a brake and free-wheeling clutch. Referring again to FIG. 6, when the input member 26 is driven counterclockwise about the axis 42 by the drive device 12, the torque transmitting member 30 moves along the ramp 48 from an engaged position where the member 30 is clamped between the ramp 48 of the input member 26 and the surface 52 of the output member 28 if the clutch assembly 24 is engaged, to a disengaged position where the member 30 is not engaged with the surface 52 of the output member 28, or remains in the disengaged position if the clutch assembly 22 is already disengaged. Referring again to FIG. 5, when the member 30 is in the disengaged position, the cage 32 and rotatable member 34 of the drag assembly 24 are driven counterclockwise by the rotation of the input member 26 of the clutch assembly 22. Counterclockwise rotation of the rotatable member 34 relative to the fixed member 36 of the drag assembly 24 moves the torque transmitting member 40 of the drag assembly 24 from a disengaged position to an engaged position, where the member 40 is clamped between the rotatable member 34 and the fixed member 36 and engages corresponding surfaces 66, 70 of the rotatable member 34 and the fixed member 36. Because the fixed member 36 is secured against rotation via its attachment to the ground frame 38, a braking torque is applied to the rotatable member 34, preventing further rotation of the rotatable member 34. Because the cage 32 is coupled to the rotatable member 34, the rotatable member 34 applies a relatively large drag to the cage 32, preventing further rotation of the cage 32 and torque transmitting member 30 of the clutch assembly 22 about axis 42, and therefore further rotation of the input member 26 in the counterclockwise direction about axis 42. As a result, clutch 20 brakes rotation of input member 26 in the counterclockwise direction and may also brake rotation of drive device 12, depending on the coupling between drive device 12 and input member 26. Because clutch assembly 22 is disengaged, output member 28 may rotate (freely rotate) relative to input member 26 in either rotational direction.The input member 26, cage 32, and rotatable member 30 remain stationary unless or until the torque driving the input member 26 in the counterclockwise direction exceeds the frictional forces maintaining the connection between (i) the rotatable member 34 and the torque transmitting member 40 of the drag assembly 24, (ii) the torque transmitting member 40 and the fixed member 36, or (iii) the fixed member 36 and the ground frame 38. Thus, one or more elements of the drag assembly 24 may be configured to establish a predetermined amount of torque that allows the input member 26 to rotate in the counterclockwise direction when torque is applied to the input member 26 of the clutch assembly 22. For example, an interference fit between the fixed member 36 and the ground frame 38 may be configured to establish this predetermined amount of torque, thereby allowing the fixed member 36 and other elements of the drag assembly 24 to rotate when the predetermined amount of torque is applied, avoiding potential damage to the drag assembly 24.

[0029] A clutch 20 according to the present teachings represents an improvement over conventional clutches. Specifically, the clutch 20 allows for a combination of operating modes in which a drive or input member 26 of the clutch 20 can drive a driven or output member 28 of the clutch 20 in a first direction, the driven or output member 28 can overrun the drive or input member 26 in the first direction, and can freely rotate in a second direction relative to the drive or input member 26, while rotation of the drive or input member 26 in the second direction is prevented.

[0030] While the present invention has been illustrated and described with reference to one or more specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.

Claims

1. 1. A clutch assembly comprising: an input member disposed about a first axis of rotation and coupled to a drive device; an output member disposed about the first axis of rotation and coupled to a driven device; a plurality of torque transmission members disposed between the input member and the output member, wherein rotation of the input member relative to the output member in a first rotational direction about the first axis of rotation engages the plurality of torque transmission members with the output member, and rotation of the output member relative to the input member in the first rotational direction about the first axis of rotation disengages the plurality of torque transmission members from the output member; and a cage configured to hold the plurality of torque transmitting members and configured to rotate with the input member; a clutch assembly including:

1. A drag assembly comprising: a rotatable member disposed about a second axis of rotation and coupled to the cage of the clutch assembly for rotation therewith; a fixed member fixed against rotation about the second axis of rotation, wherein the rotatable member rotates relative to the fixed member about the second axis in the first rotational direction, but rotation of the rotatable member relative to the fixed member about the second axis in a second rotational direction opposite the first rotational direction, thereby limiting rotation of the input member of the clutch assembly in the second rotational direction about the first axis; and a drag assembly including: A clutch equipped with a

2. 2. The clutch of claim 1, wherein said second axis of rotation is coincident with said first axis of rotation.

3. 2. The clutch of claim 1, wherein said input member is disposed radially inward of said output member.

4. 2. The clutch of claim 1, wherein said input member is disposed radially outward of said output member.

5. 2. The clutch of claim 1, wherein said plurality of torque transmitting members of said clutch assembly comprise rollers, said input member defining a plurality of inclined surfaces facing said output member, said rollers moving along said plurality of inclined surfaces.

6. 2. The clutch of claim 1, wherein the cage includes a first axially extending portion extending between the input member and the output member of the clutch assembly, a second axially extending portion coupled to the rotatable member of the drag assembly, and a radially extending portion extending between the first axially extending portion and the second axially extending portion.

7. 2. The clutch of claim 1, wherein the cage engages a first radial surface of the rotatable member opposite a second radial surface of the rotatable member that faces the fixed member.

8. 2. The clutch of claim 1, further comprising a ground frame engaging said stationary member with an interference fit.

9. 2. The clutch of claim 1, wherein the drag assembly further includes a plurality of torque transmission members disposed between the rotatable member and the fixed member, wherein rotation of the rotatable member relative to the fixed member in the first rotational direction about the second axis of rotation disengages the plurality of torque transmission members of the drag assembly from at least one of the rotatable member and the fixed member, and rotation of the rotatable member relative to the fixed member in the second rotational direction about the second axis of rotation engages the plurality of torque transmission members of the drag assembly with both the rotatable member and the fixed member.

10. 2. The clutch of claim 1, wherein rotation of the output member relative to the input member in the second rotational direction about the first axis of rotation at a first torque while rotation of the input member relative to the output member in the first rotational direction at a second torque less than the first torque disengages the output member from the plurality of torque transmitting members to permit rotation of the input member in the first rotational direction about the first axis of rotation and rotation of the output member in the second rotational direction about the first axis of rotation.

11. 1. A clutch assembly comprising: a first member disposed about a first axis of rotation; a second member disposed about the first axis of rotation and radially spaced from the first member; a plurality of torque transmission members disposed between the first member and the second member, wherein rotation of the first member relative to the second member in a first rotational direction about the first axis of rotation engages the plurality of torque transmission members with the second member, and rotation of the second member relative to the first member in the first rotational direction about the first axis of rotation disengages the plurality of torque transmission members from the second member; and a cage configured to hold the plurality of torque transmitting members and configured to rotate with the first member; a clutch assembly including:

1. A drag assembly comprising: a rotatable member disposed about a second axis of rotation and coupled to the cage of the clutch assembly for rotation therewith; a fixed member fixed against rotation about the second axis of rotation, wherein the rotatable member rotates relative to the fixed member about the second axis in the first rotational direction, but rotation of the rotatable member relative to the fixed member about the second axis in a second rotational direction opposite the first rotational direction, thereby limiting rotation of the clutch assembly input member in the second rotational direction about the first axis; and a drag assembly including: A clutch equipped with a

12. 12. The clutch of claim 11, wherein the second axis of rotation is coincident with the first axis of rotation.

13. 12. The clutch of claim 11, wherein said first member is disposed radially inward of said second member.

14. 12. The clutch of claim 11, wherein said first member is disposed radially outward of said second member.

15. 12. The clutch of claim 11, wherein the plurality of torque transmitting members of the first clutch assembly comprise rollers, the first member defining a plurality of angled surfaces facing the second member, the rollers moving along the plurality of angled surfaces.

16. 12. The clutch of claim 11, wherein the cage includes a first axial extension extending between the first and second members of the clutch assembly, a second axial extension coupled to the rotatable member of the drag assembly, and a radial extension extending between the first and second axial extensions.

17. 12. The clutch of claim 11, wherein the cage engages a first radial surface of the rotatable member opposite a second radial surface of the rotatable member that faces the fixed member.

18. 12. The clutch of claim 11, further comprising a ground frame engaging said stationary member with an interference fit.

19. 12. The clutch of claim 11, wherein the drag assembly further includes a plurality of torque transmission members disposed between the rotatable member and the fixed member, wherein rotation of the rotatable member relative to the fixed member in the first rotational direction about the second axis of rotation disengages the plurality of torque transmission members of the drag assembly from at least one of the rotatable member and the fixed member, and rotation of the rotatable member relative to the fixed member in the second rotational direction about the second axis of rotation engages the plurality of torque transmission members of the drag assembly with both the rotatable member and the fixed member.

20. 12. The clutch of claim 11, wherein rotation of the second member relative to the first member in the second rotational direction about the first axis of rotation at a first torque while rotating the first member relative to the second member in the first rotational direction at a second torque less than the first torque disengages the second member from the plurality of torque transmitting members to permit rotation of the first member in the first rotational direction about the first axis of rotation and rotation of the second member in the second rotational direction about the first axis of rotation.

Images