Coupling device for coupling / decoupling a rotary movement of a first shaft and a second shaft of a motor vehicle

Abstract

Coupling device (1) for coupling / uncoupling a rotary movement of a first shaft (2) and a second shaft (3) of a motor vehicle, comprising a switching element (4) which is arranged on the first shaft (2) in a rotationally fixed and axially displaceable manner between a first position in which a rotational movement of the first shaft (2) is coupled to a rotational movement of the second shaft (3), and a second position in which the rotational movement of the first shaft (2) is decoupled from the rotational movement of the second shaft (3), and an adjusting device (5, 6) which has an adjusting element (5) which is rotatably mounted about an axis of rotation (Y) at least between a first position and a second position and has an eccentric section (51), and an elastic return element (6) for displacing the switching element (4) between the first position and the second position, wherein the switching element (4) is arranged between the elastic return element (6) and the eccentric section (51), and the elastic return element (6) is adapted to press the switching element (4) in the direction of the eccentric section (51) in order to displace the switching element (4) into a position selected from the first position and the second position, and in the first position of the actuating element (5), the switching element (4) is held in one position selected from the first position and the second position by means of the elastic return element (6), and in the second position of the actuating element (5), the switching element (4) is held in the other position selected from the first position and the second position by a section of an actuating surface (52) of the eccentric section (51) against a force exerted by the elastic return element (6).

Description

[0001] The present invention relates to a coupling device for coupling / decoupling a rotary movement of a first shaft and a second shaft of a motor vehicle, and in particular for coupling / decoupling a rotary movement of a drive shaft and an output shaft for transmitting a drive torque from the drive shaft to the output shaft or for canceling the transmission of the drive torque.

[0002] Furthermore, the present invention relates to a motor vehicle having a first shaft, a second shaft, and a coupling device according to the invention.

[0003] Motor vehicles with an all-wheel drive, in which the wheels of all axles, for example two axles of the motor vehicle, can be driven, usually have a coupling device with which a drive torque can be transmitted from a drive source, such as a drive shaft, to an output shaft, which transmits the drive torque to the wheels of a corresponding axle, or the transmission of the drive torque to the output shaft can be prevented.

[0004] The decoupling of the rotary movement of the output shaft, which, for example, transmits the drive torque to a rear axle of the motor vehicle, and the drive shaft occurs particularly in cases where the drive via both axles of a motor vehicle with all-wheel drive is not required in order to reduce the drag torques and resistances of all-wheel drives.

[0005] DE 102 17 576 A1, for example, discloses a coupling sleeve comprising a shifting element in the form of a shift sleeve connected to a rotating shaft by means of a wedge connection and arranged to slide along a longitudinal direction of the shaft. Coupling / uncoupling is achieved by displacing the shift sleeve along the longitudinal direction of the shaft by means of a shifting device in conjunction with a locking ball.

[0006] Furthermore, WO 2012 / 171709 A1 discloses a connecting device of a vehicle drive train for rotationally coupling a vehicle shaft to a vehicle drive train element rotatable relative thereto. This connecting device comprises a shifting element configured as a sliding sleeve, which is arranged on the vehicle shaft in a rotationally fixed and axially displaceable manner between at least a first and second position. In the first position, the shifting element causes a rotational decoupling of the vehicle shaft from the vehicle drive train element, and in the second position, a rotational coupling of the vehicle shaft.The shifting element is displaced by means of adjusting means which have a shifting groove along a circumference of the shifting element and engagement means for engagement in the shifting groove, wherein the shifting groove is designed in the form of a control cam, so that when the engagement means engage in the shifting groove and when the shifting element rotates with respect to the engagement means, the shifting element is moved axially between the first and second positions by the shifting groove.

[0007] DE 39 11 381 A1 relates to a device for selectively engaging the wheels of a drive axle of a motor vehicle with at least two drive axles, wherein the end of the wheel drive shaft carrying the wheel can be connected to the latter via a spring-loaded separating clutch which can be actuated by means of a pin displaceably mounted in the shaft end.

[0008] Further coupling devices are known from the documents DE 103 37 629 A1, DE 10 2007 020 381 A1, DE 29 43 142 A1 and DE 12 66 559 A.

[0009] It is an object of the present invention to provide a coupling device for coupling / uncoupling a rotary movement of a first shaft and a second shaft of a motor vehicle, in which a displacement of the switching element takes place in an alternative manner.

[0010] This object is achieved by a coupling device for coupling / uncoupling a rotary movement of a first shaft and a second shaft of a motor vehicle having the features of patent claim 1.

[0011] Advantageous embodiments and further developments of the invention emerge from the dependent claims.

[0012] A coupling device for coupling / decoupling a rotary movement of a first shaft and a second shaft of a motor vehicle comprises a switching element which is arranged on the first shaft in a rotationally fixed manner and axially displaceable between a first position in which a rotary movement of the first shaft is coupled to a rotary movement of the second shaft, and a second position in which the rotary movement of the first shaft is decoupled from the rotary movement of the second shaft, and an adjusting device which has an adjusting element which is rotatably mounted about an axis of rotation at least between a first position and a second position and has an eccentric section, and an elastic return element for displacing the switching element between the first position and the second position.The switching element is arranged between the elastic return element and the eccentric section, wherein the elastic return element is configured to press the switching element towards the eccentric section in order to displace the switching element into a position selected from the first position and the second position. In the first position of the actuating element, the switching element is held in one position selected from the first position and the second position by means of the elastic return element, and in the second position of the actuating element, the switching element is held in the other position selected from the first position and the second position by a portion of an actuating surface of the eccentric section against a force exerted by the elastic return element.

[0013] The first shaft and the second shaft, which can be designed as hollow shafts, can be components of a drive train, such as a transfer case of the motor vehicle, in particular of an all-wheel drive vehicle, and can preferably be arranged coaxially. The first shaft can be designed, for example, as a drive shaft of the motor vehicle, which is connected to a main transmission of the motor vehicle and rotates continuously during driving operation, while the second shaft can be designed, for example, as an output shaft, which transmits a drive torque of the first shaft to an axle of the motor vehicle, for example, a rear axle.

[0014] According to one embodiment, a distance of a first portion of the actuating surface of the eccentric portion from the rotational axis and a distance of a second portion of the actuating surface of the eccentric portion from the rotational axis are different.

[0015] A cross-section of the eccentric section perpendicular to the axis of rotation of the adjusting element can be eccentric.

[0016] In one embodiment, the axis of rotation of the actuating element can extend perpendicularly and radially to the axial direction or the longitudinal axis of the first shaft. This embodiment is particularly advantageous because, when switching between the first position and the second position and vice versa, the actuating element can be rotated in the same direction of rotation without coming into contact with the first shaft.

[0017] In other embodiments, the axis of rotation of the actuating element can also extend merely perpendicular to the axial direction, and not radially, but rather, for example, tangentially to the first shaft. In this case, for example, the directions of rotation for switching between the first position and the second position and for switching between the second position and the first position could be selected to be opposite.

[0018] In further embodiments, the axis of rotation of the actuating element can also extend arbitrarily with respect to the longitudinal direction of the first shaft.

[0019] In one embodiment, the actuating surface is designed to continuously displace the switching element in the direction of the other position selected from the first position and the second position upon rotation of the actuating element about the rotation axis, starting from the first position of the actuating element, until the second position of the actuating element is reached.

[0020] Preferably, the actuating element comprises an actuator which is fixedly connected to the eccentric section and which is designed to be operated electromagnetically or electromechanically in order to rotate the actuating element at least between the first position and the second position.

[0021] The elastic return element can in particular be arranged axially on the first shaft under a prestress between a first end of the switching element and a first support device provided on the first shaft, wherein the elastic return element is designed, for example, as a spiral spring which is plugged onto the first shaft.

[0022] Preferably, the first support device has a projection projecting in the axial direction, wherein a first end portion of the elastic return element is provided between the axially projecting projection of the first support device and a portion of the first shaft. This allows the position of the first end portion of the elastic return element to be fixed, thereby preventing the first end portion of the elastic return element from being moved beyond the first support device.

[0023] The first shaft may further comprise a second support device against which a second end of the switching element is pressed in the one position selected from the first position and the second position. By providing the second support device, the one position can advantageously be precisely defined.

[0024] In one embodiment, a projection projecting in the axial direction can be provided at the first end of the switching element, wherein a second end portion of the elastic return element can be provided between the projection projecting in the axial direction of the switching element and the first shaft.

[0025] Preferably, the switching element has a support projection extending radially relative to the axial direction of the first shaft, with an axial bearing provided between the support projection and the eccentric portion. In this way, energy loss that would otherwise occur due to friction between the eccentric portion and the second end of the switching element can be prevented.

[0026] The switching element can in particular have at least one engagement means which is designed to engage with a receiving means formed on the second shaft when the switching element is in the first position in which the rotational movements of the first shaft and the second shaft are coupled.

[0027] In other embodiments, the at least one engagement means can also be provided on a separate component that is operatively connected to the switching element. Likewise, a corresponding receiving means, into which the at least one engagement means engages in order to transmit the rotational movement of the first shaft to the second shaft, can be provided on a separate component that is operatively connected to the second shaft.

[0028] In one embodiment, the engagement means is formed as a radially outwardly projecting projection of an outer surface of the switching means.

[0029] In other embodiments, both the engagement means and the receiving means may be designed in the form of one or more lamellae, each extending in the axial direction or in the longitudinal direction of the first and / or the second shaft.

[0030] A motor vehicle according to the invention, in particular an all-wheel drive vehicle, has a first shaft, a second shaft and a coupling device according to one of the preceding claims.

[0031] Preferred embodiments of the invention are explained below by way of example with reference to the figures.

[0032] They show: Fig. 1 a schematic cross-sectional view of a coupling device according to the invention for coupling / uncoupling a rotary movement of a first shaft and a second shaft of a motor vehicle, Fig. 2 a cross-sectional view of a Fig. 1 shown switching element along the Fig. 1 indicated section line AA, and Fig. 3 a cross-sectional view of an eccentric section of a Fig. 1 along the axis shown in Fig. 1 specified section line BB.

[0033] Fig. 1 is a schematic cross-sectional view of a coupling device according to the invention for coupling / uncoupling a rotational movement of a first shaft and a second shaft of a motor vehicle.

[0034] A coupling device 1 according to the invention has an adjusting device 5, 6, by means of which a switching element 4 can be displaced axially or along a longitudinal direction X of the first shaft 2 between a first position in which a rotational movement of a first shaft 2 is coupled to a rotational movement of a second shaft 3, and a second position in which the rotational movement of the first shaft 2 is decoupled from the rotational movement of the second shaft 3.

[0035] The first shaft 2 and the second shaft 3, which are preferably designed as hollow shafts, can be components of a drive train, such as a transfer case of the motor vehicle, in particular of an all-wheel drive vehicle, and can preferably be arranged coaxially, wherein in the Fig. 1, an end portion 31 of the second shaft 3 and an end portion of the first shaft 2 overlap within a housing 11 of the coupling device 1, and the end portion 31 of the second shaft 3 has an inner diameter that is larger than an outer diameter of the end portion of the first shaft 2.

[0036] The first shaft 2 can be designed, for example, as a drive shaft of the motor vehicle, which is connected to a main transmission of the motor vehicle and rotates continuously during driving, and the second shaft 3 can be designed, for example, as an output shaft, which transmits a drive torque of the first shaft 2 to an axle of the vehicle, for example a rear axle.

[0037] The switching element 4, which can be designed, for example, as a switching sleeve that encloses a section of the outer surface of the first shaft 2, is rotationally fixed and, as indicated by the double arrow in Fig. 1, axially displaceable, in particular within a predetermined range and only displaceable in the axial direction X or longitudinal direction X of the first shaft 2, attached to or on the first shaft 2.

[0038] To couple the rotary movement of the first shaft 2 and the second shaft 3, the switching element 4 is provided with engagement means 43, which are arranged as shown in Fig. 1 illustrated embodiment can be formed, for example, as teeth and in particular as radially outwardly projecting projections of the outer surface of the switching element 4.

[0039] The end section 31 of the second shaft 3 has corresponding receiving means (not shown) which are matched to the engagement means 43 of the switching element 4 and which can be designed, for example, as teeth projecting into the interior of the second shaft 3 and in particular as inwardly projecting projections of an inner surface of the second shaft 3.

[0040] If the switching element 4 is in the position shown in Fig. 1, the engagement means 43 of the switching element 4 and the receiving means of the second shaft 3 engage with each other, whereby the rotational movement of the second shaft 3 is coupled to the rotational movement of the first shaft 2, and the drive torque is transmitted from the first shaft 2 to the second shaft 3.

[0041] If, however, the switching element 4 is moved from the first position into the second position (not shown), the receiving means of the second shaft 3 are arranged in the axial direction X at a distance from the engagement means 43 of the switching element 4, whereby the second shaft 3 and in particular its rotational movement is decoupled from the rotational movement of the first shaft 2.

[0042] As in Fig. 1, preferably several of the engagement means 43 of the switching element 4 and several of the receiving means of the second shaft 3 are each arranged spaced apart from one another along the axial direction X in order to achieve an improved transmission of the drive torque from the first shaft 2 to the second shaft 3 in the coupled state.

[0043] The adjusting device 5, 6 has an elastic return element 6, which is arranged between a first support device 7 of the first shaft 2 and a first end of the switching element 4 facing the first support device 7 of the first shaft 2. The elastic return element 6 can be designed, for example, as a spiral spring, which is placed or plugged onto the first shaft 2 and is preferably in contact with the outer surface of the first shaft 2.

[0044] The first support device 7 is preferably provided on or around the entire circumference of the first shaft 2 and projects radially beyond the outer surface of the first shaft 2. Furthermore, the first support device 7 can be mounted or fastened on or to an outer surface of the first shaft 2, for example, only after the switching element 4 and the elastic return element 6 have been plugged onto the first shaft 2, wherein the first support device 7 can be fastened to the first shaft 2, for example, by welding or by screwing.

[0045] The first support device 7 can, in particular, have a projection 71 extending in the axial direction X, wherein a first end of the elastic return element 6 is arranged between the projection 71 of the first support device 7 and the first shaft 2. In this way, a radial movement of the first end of the elastic return element 6 can be restricted, and in particular, it can be prevented that the first end of the elastic return element 6 can be moved beyond the first support device 7 in the axial direction.

[0046] Furthermore, a sliding bearing 10 can be provided between the first support device 7 and the end section 31 of the second shaft 3, by means of which the rotational movement of the first shaft 2 is additionally supported in the decoupled state.

[0047] The adjusting device 5, 6 further comprises an adjusting element 5, which comprises an actuator 53 and an eccentric section 51 or cam section 51 preferably firmly connected thereto, and is mounted in such a way that it can rotate about an axis of rotation Y, which is in the Fig. 1, as indicated by the arrow, extends perpendicular to the axial direction X. A position of the adjusting element 5, and in particular of the eccentric section 51, can be changed by rotation about the rotation axis Y by means of the actuator 53, which can be operated or driven both electromagnetically and electromechanically.

[0048] In one in the Fig. In the first position of the actuating element 5 shown in Figure 1, the switching element 4 is pressed or driven by a prestress of the elastic return element 6 in the direction of a second support device 8 provided on the first shaft 2, and further movement or displacement of the switching element 4 in the direction of the eccentric section 51 of the actuating element 5 is prevented. As a result, the switching element 4 is held in a position, in particular the first position, in which the second end of the switching element 4 is in contact with the second support device 8. Therefore, in the first position of the actuating element 5, the current supply to the actuator 53 can be omitted.

[0049] As in Fig. 1, the second support device 8 can be formed, for example, by a section of the first shaft 2 which has a larger outer diameter than a section of the first shaft 2 which is provided as an area in which the switching element 4 is displaceable.

[0050] If the control element 5 is rotated from the first position about the rotation axis Y by operation of the actuator 53, for example in the Fig. 1 is rotated in the direction of rotation indicated by a round arrow, an actuating surface 52 of the eccentric section 51, the cross section of which is eccentrically shaped perpendicular to the axis of rotation Y with respect to the axis of rotation Y, causes the switching element 4 to be displaced against the force of the elastic return element 6 in the axial direction X in the direction of the first support device 7, and the elastic return element 6 is compressed, whereby its length in the axial direction X is reduced.

[0051] In order to avoid a high energy loss, which would occur due to friction between the actuating surface 52 of the actuating element 5 and the second end of the switching element 4 if they were to come into direct contact, an axial bearing 9 is provided between the second end of the switching element 4 and a support projection 41 of the switching element 4 extending in the radial direction, which axial bearing 9 is mounted on the switching element 4 and is moved together with it or is displaced in the axial direction X.

[0052] During the rotation of the actuating element 5, a distance of the eccentric section 51 from the first support device 7 of the first shaft 2 decreases with increasing rotation, in particular due to the eccentric-shaped cross section of the actuating surface 52, wherein the actuating surface 52 of the eccentric section 51 increasingly displaces the switching element in the direction of the second position of the switching element 4 via the axial bearing 9 and the support projection 41 of the switching element 4.

[0053] Upon reaching a second, predetermined position of the actuating element 5, in which the switching element 4 is in the second position, the rotational movement of the actuating element 5 about the rotational axis Y is terminated in order to hold the switching means 4 in the second position, in which the rotational movement of the second shaft 3 is decoupled from the rotational movement of the first shaft 2. In this state, the current supply to the actuator 53 is preferably maintained in order to prevent the elastic return element 6 from displacing the switching element 4 back into the first position.

[0054] Fig. 2 shows a cross-sectional view of the Fig. 1 shown switching element 4 along the Fig. 1 indicated section line AA.

[0055] Again Fig. 2, a plurality of tooth-shaped engagement elements 43 are arranged spaced apart from one another in a circumferential direction of the switching element 4. In order to achieve the most effective transmission of the drive torque from the first shaft 2 to the second shaft 3, the receiving means of the second shaft 3 (not shown) preferably have a shape such that they engage with the engagement means 43 with almost no gap, ie with almost form-fitting engagement, when the switching element 4 is in the first position in which the rotational movements of the first shaft 2 and the second shaft 3 are coupled.

[0056] Fig. 3 shows a cross-sectional view of the eccentric section 51 of the Fig. 1 illustrated adjusting element 5 along the Fig. 1 specified section line BB.

[0057] The Fig.3, the actuating surface 52 of the eccentric section 51 shown in cross section has the shape of a cam disk, in particular the shape of an ellipse, wherein in particular a distance R1 of a first point P1 or a first section of the actuating surface 52 from the axis of rotation Y and a distance R2 of a second point P2 or a second section of the actuating surface 52 from the axis of rotation Y are different.

[0058] In this way, when the actuating element 5 rotates about the axis of rotation Y, starting from the first position of the actuating element 4, the distance between the actuating surface 52 and the first support device 7 is reduced, whereby the switching element 4 is displaced axially against the force of the elastic return element 6 in the direction of the first support device 7 by the contact between the actuating surface 52 of the actuating element 5 and the axial bearing 9, which is connected to the switching element 4.

[0059] When the actuating element 5 has been rotated by 180° into the second position of the actuating element 5, the maximum displacement of the switching element 4 and in particular the second position of the switching element 4 is reached, in which the second shaft 3 and in particular its rotational movement is decoupled from the first shaft 2.

[0060] If the actuating element 5 is rotated by a further 180° about the rotation axis Y, the actuating element 5 is again in the first position and the switching element 4 is again in the first position, and the second shaft 3, in particular its rotational movement, is coupled to the rotational movement of the first shaft 2.

Claims

[1] Coupling device (1) for coupling / uncoupling a rotary movement of a first shaft (2) and a second shaft (3) of a motor vehicle, comprising a switching element (4) which is arranged on the first shaft (2) in a rotationally fixed and axially displaceable manner between a first position in which a rotational movement of the first shaft (2) is coupled to a rotational movement of the second shaft (3), and a second position in which the rotational movement of the first shaft (2) is decoupled from the rotational movement of the second shaft (3), and an adjusting device (5, 6) which has an adjusting element (5) which is rotatably mounted about an axis of rotation (Y) at least between a first position and a second position and has an eccentric section (51), and an elastic return element (6) for displacing the switching element (4) between the first position and the second position, wherein the switching element (4) is arranged between the elastic return element (6) and the eccentric section (51), and the elastic return element (6) is adapted to press the switching element (4) in the direction of the eccentric section (51) in order to displace the switching element (4) into a position selected from the first position and the second position, and in the first position of the actuating element (5), the switching element (4) is held in one position selected from the first position and the second position by means of the elastic return element (6), and in the second position of the actuating element (5), the switching element (4) is held in the other position selected from the first position and the second position by a section of an actuating surface (52) of the eccentric section (51) against a force exerted by the elastic return element (6). [2] Coupling device (1) according to claim 1, wherein a distance of a first portion of the actuating surface (52) from the rotational axis (Y) of the actuating element (5) and a distance of a second portion of the actuating surface (52) from the rotational axis (Y) of the actuating element (5) are different. [3] Coupling device (1) according to claim 1 or 2, wherein a cross section of the eccentric portion (51) perpendicular to the axis of rotation (Y) of the actuating element (5) is eccentric-shaped. [4] Coupling device (1) according to one of claims 1 to 3, wherein the actuating surface (51) is configured to continuously displace the switching element (4) in the direction of the other position selected from the first position and the second position upon rotation of the actuating element (5) about the rotation axis (Y) starting from the first position of the actuating element (5) until the second position of the actuating element (5) is reached. [5] Coupling device (1) according to one of claims 1 to 4, wherein the actuating element (5) further comprises an actuator (53) which is fixedly connected to the eccentric section (51) and which is designed to be operated electromagnetically or electromechanically in order to rotate the actuating element (5) at least between the first position and the second position. [6] Coupling device (1) according to one of claims 1 to 5, wherein the elastic return element (6) is arranged axially on the first shaft (2) under a prestress between a first end of the switching element (4) and a first support device (7) provided on the first shaft (2). [7] Coupling device (1) according to claim 6, wherein the first support device (7) has a projection (71) projecting in the axial direction, and a first end portion of the elastic return element (6) is provided between the projection (71) projecting in the axial direction of the first support device (7) and a portion of the first shaft (2). [8] Coupling device (1) according to one of claims 1 to 7, wherein the first shaft (2) has a second support device (8) against which a second end of the switching element (4) is pressed in the one position selected from the first position and the second position. [9] Coupling device (1) according to claim 8, wherein an axially projecting projection (42) is provided at the first end of the switching element (4), and a second end portion of the elastic return element (6) is provided between the axially projecting projection (42) of the switching element (4) and the first shaft (2). [10] Coupling device (1) according to one of claims 1 to 9, wherein the switching element (4) has a support projection (41) extending in the radial direction with respect to the axial direction of the first shaft (2), and an axial bearing (9) is provided between the support projection (41) and the eccentric section (51). [11] Coupling device (1) according to one of claims 1 to 10, wherein the switching element (4) has at least one engagement means (43) which is designed to engage with a receiving means formed on the second shaft (3) when the switching element (4) is in the first position. [12] Coupling device (1) according to claim 11, wherein the engagement means (43) is formed as a radially outwardly projecting projection of an outer surface of the switching means (4). [13] Motor vehicle comprising a first shaft (2), a second shaft (3) and a coupling device (1) according to one of the preceding claims.

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