Coupling device

Abstract

Coupling device (100), comprising: - a first (110) and a second support element (115) which are rotatably mounted about a common axis of rotation (105); - first friction elements (125) which engage with the first support element (110) in a torque-locking manner; - second friction elements (130) which engage with the second support element (115) in a torque-locking manner; - wherein the first (125) and second friction elements (130) are arranged axially alternately; where - the second friction elements (130) are axially elastically deformable, - wherein the first friction elements (125) are axially displaceable on the first support element (110) and the second friction elements (130) are held on the second support element (115) at predetermined axial distances (160), - wherein the second friction element (130) further comprises the following: - a radially inner section (185) where it is axially fixed to the second support element (115); - a radially central section (180) that lies radially between the inner and outer sections, - wherein the radially central section (180) is axially flexible, - wherein the second friction elements (130) are held torque-locking on the second support element (115) by means of a toothing (135, 140) and axially pressed onto the toothing (135, 140).

Description

[0001] The invention relates to a clutch device. In particular, the invention relates to a clutch device for use in a drive train of a motor vehicle.

[0002] A motor vehicle comprises a drive train with a clutch device. The clutch device can in particular be provided between a drive engine and a transmission. The clutch device comprises an input side and an output side, which are mounted for rotation about a common axis of rotation. The input side is connected to an inner basket and the output side to an outer basket in a torque-locking manner. A plurality of first friction elements are attached to the outer basket by means of a toothing, and a plurality of second friction elements are attached to the inner basket, likewise by means of a toothing, each in a torque-locking and axially displaceable manner. If the friction elements are pressed axially against one another, a frictional connection is created between the first and friction elements, so that torque can be transmitted between the input side and the output side.

[0003] Particularly when the clutch device is wet-running, meaning it operates in a bath of fluid, a certain force coupling can exist between the first and second friction elements, even in the absence of axial compression. This coupling is called drag torque. The drag torque is primarily caused by shearing of the fluid between the first and second friction elements. This drag torque can lead to the clutch device not fully disengaging, resulting in, for example, an improper gear shift in the connected transmission.

[0004] As state of the art, reference is made, for example, to DE 10 2008 006 155 A1 and DE 682 187 A.

[0005] The present invention is based on the object of providing an improved separating coupling device. The invention achieves this object by means of a coupling device having the features of the independent claim. Subclaims specify preferred embodiments.

[0006] A clutch device comprises a first and a second carrier element, which are mounted for rotation about a common axis of rotation, first friction elements that engage the first carrier element in a torque-locking manner, and second friction elements that engage the second carrier element in a torque-locking manner. The first and second friction elements are arranged axially alternating, and the second friction elements are axially elastically deformable.

[0007] The axially flexible second friction elements ensure that the clutch device closes completely when the friction elements are pressed axially against each other and opens completely again when the axial contact force is sufficiently reduced.

[0008] Furthermore, when the clutch device is closed, i.e., when the set of first and second friction elements is successively pressed axially against one another, the friction elements can be frictionally engaged with one another in a more even manner, so that thermal loading of the friction elements can be more evenly distributed. A similar effect can occur when the clutch device is opened. Wear on the clutch device can thereby be reduced overall. Furthermore, forces acting in the circumferential direction between the first friction elements and the first carrier element can also be made more even, so that wear in this area, for example due to abrasion, can also be made more even and thus reduced overall.

[0009] According to the invention, the first friction elements are mounted axially displaceably on the first carrier element and the second friction elements are held on the second carrier element at predetermined axial intervals.

[0010] The second friction elements, which are fixed at predetermined axial intervals, can ensure that, when the friction elements are not subjected to axial load, there is sufficient space between a first and a second friction element, so that the friction elements transmit a reduced torque. This can be particularly true when the clutch device runs in a fluid bath and the fluid lies between the first and second friction elements. The torque flow through the disengaged clutch device can thus be interrupted in an improved manner. For example, when the clutch device is used in a drive train with a transmission, gear changes in the transmission can be carried out more effectively when the clutch device is disengaged.

[0011] One of the axially elastic second friction elements can comprise a radially outer section, at which the friction element lies axially adjacent to a contact surface of an adjacent first friction element, wherein the second friction element is axially rigid in the radially outer section. As a result, the second friction element can, for example, carry a friction lining in the outer section, which can be hard or brittle. By limiting the axial deformability of the second friction element, the contact pattern of the first and second friction elements against one another can be improved. In other words, the parts of the axial contact surfaces of the first and second friction elements that abut one another when the friction elements are axially compressed can be enlarged.

[0012] The second friction element further comprises a radially inner portion, where it is axially fixedly held on the second support element, and a radially central portion located radially between the inner and outer portions. The radially central portion is axially flexible. The axial deformability of the second friction element can thus be limited to a defined radial region, which can be designed to simultaneously transmit forces acting in the circumferential direction and be axially elastically deformable.

[0013] The friction element may have an axial opening in the central section. This opening can help ensure the axial elastic deformability of the second friction element.

[0014] In one embodiment, the aperture extends further in the circumferential direction than in the radial direction. This can further increase the axial deformability of the second friction element.

[0015] In a further embodiment, the aperture is open radially inward. In other words, the aperture extends radially inward to a radially inner boundary of the second friction element.

[0016] The second friction elements can comprise steel plates. This allows for improved axial elastic deformability of the two friction elements. Furthermore, the second friction elements can be fixed to the second support element in an axially immobile manner, for example, by means of a clamp fit. Despite the axial deformability, the transmission capacity for forces acting in the circumferential direction in the radial direction can be good.

[0017] In one embodiment of the invention, the second friction elements are held in a torque-locking manner on the second carrier element by means of a toothing and are axially pressed onto the toothing. The pressing can ensure the relative axial spacing of the second friction elements on the second carrier element. Additionally, the relative spacing can be ensured by appropriately inserted spacer rings or similar devices.

[0018] An axial distance between two axially unloaded, adjacent second friction elements is preferably greater than the thickness of a first friction element located between them. It is particularly preferred that the axial distance be greater than the thickness of the first friction element by a predetermined amount. This ensures that the distance has a minimum size, even with unworn first and / or second friction elements, that can ensure complete disengagement of the clutch device.

[0019] The invention will now be described in more detail with reference to the accompanying figures, in which: Fig. 1 a half-section through a coupling device; Fig. 2 an axial view of a friction element for the clutch device of Fig. 1 in a first embodiment; and Fig. 3 a friction element for the clutch device of Fig. 1 in a second embodiment.

[0020] Fig. 1 shows a half-section through one coupling device 100. A first carrier element 110 and a second carrier element 115 are rotatably mounted about a rotation axis 105. In the illustrated embodiment, the first carrier element 110 is located radially outward and can also be referred to as the outer basket, while the second carrier element 115 is located radially inward and can also be referred to as the inner basket. Typically, both carrier elements 110, 115 are provided on one side axially with a radial section through which a torque can be introduced or discharged. With regard to the technology presented here, however, the relative inner and outer positions between the carrier elements 110 and 115 can also be reversed.

[0021] In a radial region between the first carrier element 110 and the second carrier element 115 lies a disk pack 120 comprising an axially alternating arrangement of first friction elements 125 and second friction elements 130. The first friction elements 125 are torque-locked to the first carrier element 110. Axial spacings between the first friction elements 125 are fixed, so that the first friction elements 125 are preferably rigidly attached to the first carrier element 110 rather than by means of toothing, as is usual, which would allow axial movement of the first friction elements 15. A welded or screwed connection, for example, is suitable for this purpose. A positive connection such as toothing can also be used.

[0022] However, the first friction elements 125 are designed to be elastically deformable in the axial direction, so that they are axially movable in a region lying radially inside the first carrier element 110. The first friction elements 125 can each carry a friction lining 145 axially on one or both sides. The second friction elements 130 are preferably designed in the same way as the first friction elements 125. For this purpose, the second friction elements 130 can also carry a friction lining 145 axially on one or both sides. In a preferred embodiment, however, the second friction elements 130 are designed as steel plates that do not carry a friction lining 145. To transmit forces acting in the circumferential direction around the rotation axis 105, the second friction elements 130 can each carry an internal toothing 135 that positively engages an external toothing 140 formed on the second carrier element 115.

[0023] It is proposed that the second friction elements 130 be fastened to the second carrier element 115 at predetermined axial intervals. The second friction elements 130 are axially fixed relative to the second carrier element 115. Furthermore, it is preferred that the second friction elements 130 be flexible, so that they can better engage axially adjacent first friction elements 125 when the disk pack 120 is axially compressed to close the clutch device 100. A corresponding actuation or closing mechanism for the clutch device 100 can be implemented in any desired manner. Preferably, the clutch device 100 is designed to be wet-running, i.e., to run in a bath of fluid 150, wherein the fluid 150 can also be used, for example, for the hydraulic actuation of the closing mechanism.

[0024] The second friction elements 130 can, for example, also be axially pressed onto the second carrier element 115, so that the press fit ensures their axial immobility on the second carrier element 115. Optionally, a different connection technique can also be selected, which can be designed either as a form-fitting, force-fitting, or material-fitting connection. In a further embodiment, a spacer element 155 is provided between two adjacent second friction elements 130 in the region of the second carrier element 115, the axial width of which defines the axial distance between the two adjacent second friction elements 130. The axial distance 160 between two adjacent second friction elements 130 is defined as the distance between mutually facing contact surfaces 165, which each face corresponding contact surfaces 165 of a first friction element 125 located axially between the two second friction elements 130.It is preferred that the axial distance 160—optionally controlled by a spacer element 155—be larger by a predetermined amount than the axial width 170 of a first friction element 125 located between the second friction elements 130. During prolonged operation of the clutch device 100, the friction elements 125 and / or 130 may wear, so that the axial distance 160 may become larger or the axial width 170 may become smaller.

[0025] In one embodiment, the axially elastic deformability of the second friction elements 130 is limited to a predetermined radial section. For this purpose, a distinction is made between a radially outer section 175, a radially middle section 180, and a radially inner section 185, which adjoin one another in the order mentioned. The outer section 175 extends beyond the axial contact surface 165 of the second friction element 130. Should a part of the second friction element 130 protrude radially outward beyond the contact surface 165, it can also be counted as the outer section 175. The radially inner section 185 of the second friction element 130 consists of the region in which the second friction element 130 is held on the second carrier element 115. A radial region defined by the spacer element 155 can optionally be counted as the radially inner section 185. The middle section 180 extends between the inner section 185 and the outer section 175.

[0026] In a particularly preferred embodiment, the axial flexibility of the second friction element 130 is essentially realized by the central portion 180. On the one hand, the flexibility can be deliberately achieved in the central portion 180; on the other hand, the flexibility can be reduced in the outer portion 175 by the second friction element 130 bearing against an adjacent first friction element 125 during compression of the disk pack 120, or in the inner region 185 by the axial fixation on the second carrier element 115.

[0027] Fig. Figure 2 shows an axial view of a second friction element 130 for a clutch device 100 in a first embodiment. It is proposed to use the illustrated second friction element 130 on a clutch device 100 in which the friction elements 125, 130 are axially displaceably mounted on their associated support elements 110, 115. The second friction element 130 is embodied here, by way of example, as a steel plate without a friction lining 145.

[0028] With reference to the axis of rotation 105, the sections 175, 180, and 185 are indicated in the radial direction. In the illustrated embodiment, a tooth 210 of the internal toothing 135 can be seen in the inner section 185. An axial opening 205 is provided in the central section 180, which preferably lies on the same radius as the tooth 210. The opening 205 preferably extends in the circumferential direction and is longer in this direction than in the radial direction. By means of the opening 205, the axial flexibility of the second friction element 130 can be improved in this area. Sections of the second friction element 130 lying in or against the circumferential direction with respect to the illustrated tooth 210 ensure a frictional connection from the outer area 175 to the inner area 185.A radially inner boundary of the second friction element 130 can be offset outwardly at a predetermined distance from a tooth 210 in order to save material and not impair the axial flexibility of the second friction element 130.

[0029] A corresponding embodiment can be used for the first friction element 125, in which the tooth 210 extends radially outward and is part of the external toothing 140.

[0030] Fig. 3 shows a friction element 130 for the clutch device 100 of Fig. 1 in a second embodiment. Here, too, the radial sections 175, 180, and 185 are indicated with respect to the rotation axis 105.

[0031] The axial opening 205 extends on one side to a radially inner boundary of the second friction element 130. The opening 205 is preferably crescent-shaped, wherein a section of the opening 205 can lie on a circumference around the axis of rotation 105, while another section can be curved radially inward. It is particularly preferred that the opening 205, which is open radially inward on one side, lies on a radius with a tooth 210 of the internal toothing 135, so that the opening 205 radially separates the tooth 210 from the outer section 175. The longer the opening 205 extends in the circumferential direction towards its closed end, the longer the effective lever of the tooth 210 in its anchoring on the outer section 175, so that the axial elastic deformability is facilitated. A spring constant of tooth 210 can be reduced as a result, making tooth 210 spring-softer.

[0032] This embodiment can also be used in a corresponding manner with a first friction element 125. List of reference symbols 100 coupling device 105 axis of rotation 110 first support element 115 second support element 120 slat pack 125 first friction element 130 second friction element 135 internal gearing 140 external gearing 145 Friction lining 150 Fluid 155 spacer element 160 axial distance 165 axial contact surface 170 axial width 175 radial outer section 180 radial middle section 185 radial inner section 205 Breakthrough 210 teeth

Claims

[1] Coupling device (100), comprising: - a first (110) and a second support element (115) which are rotatably mounted about a common axis of rotation (105); - first friction elements (125) which are in torque-locking engagement with the first carrier element (110); - second friction elements (130) which are in torque-locking engagement with the second carrier element (115); - wherein first (125) and second friction elements (130) are arranged axially alternately; where - the second friction elements (130) are axially elastically deformable, - wherein the first friction elements (125) are mounted axially displaceably on the first carrier element (110) and the second friction elements (130) are held on the second carrier element (115) at predetermined axial distances (160), - wherein the second friction element (130) further comprises: - a radially inner portion (185) at which it is axially fixedly held on the second support element (115); - a radially central section (180) located radially between the inner and outer sections, - wherein the radially central portion (180) is axially flexible, - wherein the second friction elements (130) are held on the second carrier element (115) in a torque-locking manner by means of a toothing (135, 140) and are axially pressed onto the toothing (135, 140). [2] Clutch device (100) according to claim 1, wherein one of the second friction elements (130) comprises a radially outer portion (175) at which it lies axially adjacent to a contact surface (165) of an adjacent first friction element (125), and wherein the second friction element (130) is axially rigid in the radially outer portion (175). [3] Coupling device (100) according to one of the preceding claims, wherein the friction element (130) has an axial opening (205) in the central section (180). [4] Coupling device (100) according to claim 3, wherein the opening (205) extends further in the circumferential direction than in the radial direction. [5] Coupling device (100) according to claim 3 or 4, wherein the opening (205) is open radially inward. [6] Clutch device (100) according to one of the preceding claims, wherein the second friction elements (130) comprise steel plates. [7] Clutch device (100) according to one of the preceding claims, wherein an axial distance (160) between two axially unloaded, adjacent second friction elements (130) is greater than the thickness (170) of a first friction element (125) lying between them.

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