Disengageable clamping clutch and drive system with such disengageable clamping clutches

Abstract

Drive system that includes: an inner race element (14); an outer race element (16); a first disengageable clamping element coupling (18) arranged between the inner race element (14) and the outer race element (16), wherein the first disengageable clamping element coupling (18) has a drive direction and a free-running direction; and a second disengageable clamping element coupling (20) arranged between the inner running ring element (14) and the outer running ring element (16), wherein the second disengageable clamping element coupling (20) has a drive direction and a freewheel direction which are opposite to the drive direction and to the freewheel direction of the first disengageable clamping element coupling (18); characterized by the fact that (i) the first disengageable clamping clutch (18) and the second disengageable clamping clutch (20) each include a disengagement mechanism to prevent the first and second disengageable clamping clutches (18, 20) from being engaged in a drive direction; wherein the release mechanism includes an extendable ring (42) which engages the clamping elements of the first disengageable clamping element coupling (18) or the second disengageable clamping element coupling (20), and when it is stretched, prevents the clamping elements from engaging the inner running ring element (14); or (ii) the first disengageable clamping element coupling (18) and the second disengageable clamping element coupling (20) each contain several clamping elements (30) with a clamping surface (30d) for engaging the inner running ring element (14) and wherein the several clamping elements (30) each contain a recess (30e) within the clamping surface (30d), wherein in the recess (30e) each of the clamping elements (30) receives an expandable ring (42).

Description

INTRODUCTION

[0001] The present invention relates to a disengageable clamping element coupling according to the preamble of claim 2 and a drive system according to the preamble of claim 1 with two clamping element couplings designed to supply a torque in opposite directions of rotation or simply to change the relative angular position of the inner race relative to the outer race.

[0002] A clamping coupling according to the preamble of claim 2 is disclosed in DE 101 44 032 A1 and a drive system according to the preamble of claim 1 is disclosed in DE 359 468 A. Further prior art is disclosed in DE 10 2010 039 951 A1.

[0003] A sprag clutch is a freewheel drive device with an inner and an outer race, each of which can be the input or output element. The input element can be designed to drive the output element in a selected direction and allow the output element to freewheel in the opposite direction. Sprag clutches are capable of transmitting high torques within small overall dimensions.

[0004] A sprag clutch contains an array of shaped steel sprags located in an annular space between the concentric inner and outer races. The sprags clamp between the two races, transferring power from one race to the other. Each sprag is shaped such that rotation of a race in the 'drive' direction causes the sprags to tilt, thus transferring the torque completely from one race to the other. Conversely, rotation of the race in the opposite direction releases the sprags, allowing free movement between the races. SUMMARY

[0005] According to the invention, a drive system is presented which is characterized by the features of claim 1.

[0006] Furthermore, a clamping body coupling is presented according to the invention, which is characterized by the features of claim 2.

[0007] According to another aspect, a clamping body for use in a clamping body coupling comprises a metal body with a support area having a pair of recesses at each end, each defining a support rib. Furthermore, the metal body includes a clamping surface with a recess provided in the clamping surface.

[0008] Further areas of application of the present invention will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples are for illustrative purposes only. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be more fully understood from the detailed description and the accompanying drawings; these show: Fig. 1 a longitudinal sectional view of a dual clamping body coupling system for a shaft; Fig. 2 a cross-sectional view of a first clamping body coupling arrangement of the dual clamping body coupling system according to the principles of the present invention; Fig. 3 a cross-sectional view of a second clamping body coupling arrangement of the dual clamping body coupling system according to the principles of the present invention; Fig. 4 a perspective view of an exemplary clamping body coupling arrangement according to the principles of the present invention; and Fig. 5 a perspective view of an exemplary clamping body coupling element according to the principles of the present invention.

[0010] Reference symbols may be used multiple times in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0011] Based on Fig. Figure 1 now describes a longitudinal sectional view of an exemplary torque transmission system 10 with a dual clamping element coupling system 12. The torque transmission system 10 comprises an inner running ring element 14 and an outer running ring element 16. The inner running ring element 14 and the outer running ring element 16 can be separate drive elements or driven elements of the drive system. The inner running ring element 14 and the outer running ring element 16 can be engaged by a pair of oppositely oriented disengageable clamping element couplings 18, 20. The outer running ring element 16 can be rotatably supported on the inner running ring element 14 by a pair of bearings 22.

[0012] Based on Fig. 2 The first clamping element coupling 18 is designed to transmit a torque from the inner running ring element 14 to the outer running ring element 16 when the inner running ring element 14, for example, as in Fig. As shown in Figure 2, the first clamping element coupling 18 is rotated counterclockwise. Conversely, the first clamping element coupling 18 is designed not to transmit any torque to the outer race element 16, so that the first clamping element coupling runs freely when the inner race element 14 is rotated clockwise.

[0013] In particular, the first clamping element coupling 18 includes an arrangement of wedge-shaped steel clamping elements 30 located in an annular space between the inner race element 14 and the outer race element 16. A clamping action of the clamping elements 30 between one of the inner and outer race elements 14, 16 and the other transmits power from one of the inner and outer race elements 14, 16 to the other. Each clamping element 30 is shaped such that rotation of the inner or outer race element 14, 16 in a "drive" direction causes the clamping elements 30 to tilt into a clamped position, thus transmitting the torque completely from one race to the other. Conversely, rotation of one of the inner and outer race elements 14, 16 in the opposite direction releases the clamping elements, allowing free rotation between the inner and outer race elements 14, 16.

[0014] The second clamping body coupling 20 is arranged opposite to the first clamping body coupling 18, so that, as in Fig. As can be seen in Figure 3, the second clamping element coupling 20 is designed not to transmit any torque to the outer race element 16, so that the second clamping element coupling runs freely when the inner race element 14 is rotated counterclockwise. Conversely, the second clamping element coupling 20 is designed to transmit a torque to the outer race element when the inner race element 14 is rotated clockwise.

[0015] The second clamping element coupling 20, like the first clamping element coupling 18, contains an arrangement of wedge-shaped steel clamping elements 30 located in an annular space between the inner raceway element 14 and the outer raceway element 16. It should be understood that the first clamping element coupling 18 and the second clamping element coupling 20 may have the same or different designs. Through a clamping action of the clamping elements 30 between the inner or outer raceway element 14, 16 and the other, power is transferred from the inner or outer raceway element 14, 16 to the other.Each clamping element 30 is shaped such that the rotation of the inner or outer race element 14, 16 in a "drive" direction, which is opposite to the drive direction of the first clamping element coupling 18, causes the clamping elements 30 to tilt into a wedged position and thus completely transmit the torque from one race to the other. Conversely, the rotation of one of the inner and outer race elements 14, 16 in the opposite direction releases the clamping elements 30 and allows free rotation between the inner and outer race elements 14, 16.

[0016] The operation of the first and second clamping element couplings 18, 20 in the driven and free-running states is typical for a clamping element coupling. However, the first and second clamping element couplings 18, 20 include a disengagement mechanism capable of disengaging the coupling, thus preventing the transmission of torque from one raceway to the other, even when rotated in the driven direction. Specifically, both the first and second clamping element couplings 18, 20 have multiple window openings 32 in the hollow, tubular inner raceway element 14. Several balls 34 are arranged in each of these multiple window openings 32. The multiple balls 34 are supported within the windows on an inner side by a piston 36 with a cam surface 38 that engages with the multiple balls 34.The piston 36 is preloaded in a first axial direction by a spring 40 that runs between the piston 36 of both the first and second clamping body couplings 18, 20. Alternative designs with an actuator that moves the piston both into and out of the engagement position can be used. Furthermore, the pistons 36 of the first and second clamping body couplings 18, 20 can be connected to each other so that they move simultaneously. The multiple balls 34 are all arranged against an inner surface of an expandable ring 42 that surrounds the inner race element 14. The expandable ring 42 can be made of spring steel and can include overlapping split ends 42a, 42b, as shown in [reference missing]. Fig. As shown in Figure 4, the ring 42 can also be referred to as a gap ring. The piston 36 can be axially depressed to cause the balls to move relative to the window openings and against the expandable gap ring along the cam surface and radially outwards. Thus, the expandable gap ring is expandable radially outwards in one direction to disengage the clamping elements 30 and support them in a disengaged position, creating a gap between the clamping elements 30 and the inner race element 14. This allows the outer race element 16 to rotate freely in either a drive or freewheel direction without the clamping elements 30 being engaged.The pistons 36 can be pressed against the preload force of the spring 38 by an actuator 44, which may include an electromagnetic actuator, a pneumatic actuator, a hydraulic actuator, a mechanical actuator or another known type of actuator, in order to disengage the corresponding clutch.

[0017] Based on Fig. 5 The clamping bodies 30 contain a radially outer support area 30a with a pair of end recesses 30b that define a rib 30c which, as in Fig.As shown in Figure 1, the clamping elements are arranged against a pressure ring 46. The pressure ring 46 can preload the clamping elements in the direction of the engaged position. It should be understood that the pressure ring can assume alternative shapes and engage the clamping elements in different ways. Furthermore, the clamping elements 30 include an inner clamping surface 30d, which engages with the inner bearing element 14. A recess 30e for receiving the expandable ring 42 is provided in the clamping surface 30d.

[0018] The first and second one-way clamping element couplings 18, 20 can be mounted opposite each other on the same rotating bearing ring elements 14, 16 and the bearing ring elements 14, 16 can be rotated in both directions relative to each other if the corresponding coupling of the couplings 18, 20 is disengaged as described above.

[0019] These disengageable couplings 14, 16 can maintain the disengagement of the clamping elements 30 by applying an internal or external force to all arranged clamping elements 30 of the coupling in an otherwise standard one-way clamping element coupling. Where previously it was strictly unidirectional, the coupling can now be rotated in the opposite direction without re-engaging (locking) the clamping elements, as would normally be the case without the internal or external force.

[0020] By combining two clamping couplings on the same drive shaft, one designed to operate in one direction and the other in the opposite direction, an interlocked drive system is created, as both couplings prevent the movement of the other. As described above, the opposite coupling can be disengaged to initiate movement in one direction, allowing the shaft to rotate in that direction. The couplings can be engaged to allow the shaft or drive element to rotate in the opposite direction. Additionally, both couplings can be engaged to allow one shaft to rotate freely in one direction.

[0021] The main advantages would be the small assembly size, the extreme robustness and durability (using a proven, decades-old technology), the simplicity and low number of parts (compared to a gearbox or rear axle differential), the instant locking and the low noise.

Claims

[1] Drive system comprising: an inner race element (14); an outer race element (16); a first disengageable clamping element coupling (18) arranged between the inner race element (14) and the outer race element (16), wherein the first disengageable clamping element coupling (18) has a drive direction and a free-running direction; and a second disengageable clamping element coupling (20) arranged between the inner running ring element (14) and the outer running ring element (16), wherein the second disengageable clamping element coupling (20) has a drive direction and a freewheel direction which are opposite to the drive direction and to the freewheel direction of the first disengageable clamping element coupling (18); characterized by , that (i) the first disengageable clamping clutch (18) and the second disengageable clamping clutch (20) each include a disengagement mechanism to prevent the first and second disengageable clamping clutches (18, 20) from being engaged in a drive direction; wherein the release mechanism includes an extendable ring (42) which engages the clamping elements of the first disengageable clamping element coupling (18) or the second disengageable clamping element coupling (20), and when it is stretched, prevents the clamping elements from engaging the inner running ring element (14); or (ii) the first disengageable clamping element coupling (18) and the second disengageable clamping element coupling (20) each contain several clamping elements (30) with a clamping surface (30d) for engaging the inner running ring element (14) and wherein the several clamping elements (30) each contain a recess (30e) within the clamping surface (30d), wherein in the recess (30e) each of the clamping elements (30) receives an expandable ring (42). [2] Clamping body coupling (18, 20) comprising: an inner race element (14); an outer race element (16); several clamping elements (30) which are supported between the inner raceway element (14) and the outer raceway element (16), each of the clamping elements (30) having a support area (30a) and a clamping surface (30d), wherein a recess (30e) is provided in the clamping surface (30d); and a ring (42) which is received in the recess (30e) of each of the several clamping bodies (30); characterized by , that the ring (42) is a stretchable split ring. [3] Clamping body coupling (18, 20) according to claim 2, wherein the ring (42) is made of spring steel. [4] Clamping element coupling (18, 20) according to claim 2, which further comprises a disengagement mechanism to prevent the multiple clamping elements (30) from being engaged in a drive direction. [5] Clamping element coupling (18, 20) according to claim 4, wherein the release mechanism stretches the ring (42) to prevent the clamping elements (30) from engaging the inner running ring element (14). [6] Clamping element coupling (18, 20) according to claim 5, wherein the release mechanism includes a piston (36) which is arranged in a cavity of the inner running ring element (14) and which has a cam surface (38) which engages with several balls (34) which are arranged within respective window openings in the inner running ring element (14) and can be engaged with the ring (42), wherein the movement of the piston (36) within the inner running ring element (14) causes the balls (34) to extend radially outwards from the window openings and stretch the extendable ring (42) in order to release the clamping elements (30) from the inner running ring element (14).

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