阅读说明：本技术 带有具备摩擦装置的摇臂式减振器的离合器从动盘；以及摩擦离合器 (A clutch driven disc with a rocker arm type vibration damper having a friction device; and a friction clutch ) 是由 P·克伦佩尔 A·鲁施 L·索瑞特 A·库伊 于 2019-03-08 设计创作，主要内容包括：本发明涉及一种用于机动车摩擦离合器离合器从动盘(1),其带有一个可围绕旋转轴(2)旋转并且具有摩擦片(3)的输入部分(4),一个同样可围绕所述旋转轴(2)旋转的输出部分(5)以及一个用来将所述输入部分(4)与所述输出部分(5)耦合的摇臂式减振器(6),其中,所述摇臂式减振器(6)进一步具有一个与所述输入部分(4)相连的第一法兰区域(7),一个在有限角度范围内可相对于所述第一法兰区域(7)围绕所述旋转轴(2)旋转并且与所述输出部分(5)相连的第二法兰区域(8)以及两个分别通过连杆装置(9、10)与所述两个法兰区域(7、8)以可活动方式耦合的中间件(11a、11b),并且其中一个弹簧单元(12)与所述连杆装置(9、10)按如下方式共同发挥作用：当所述法兰区域(7、8)彼此相对扭转时,会通过所述弹簧单元(12)阻止所述中间件(11a、11b)相互靠近的相对运动,其中,一个摩擦装置(13)按如下方式布置在所述弹簧单元(12)的弹簧元件(14)内部或外部并发挥作用,即：在所述中间件(11a、11b)的第一相对运动区域内通过所述摩擦装置(13)生成可阻止所述中间件(11a、11b)相对运动的摩擦力并且该摩擦力高于在与所述第一运动区域错位的所述中间件(11a、11b)第二相对运动区域中所生成的摩擦力。本发明还涉及一种带有所述离合器从动盘(1)的摩擦离合器。(The invention relates to a driven disk (1) for a friction clutch of a motor vehicle, having an input part (4) which can rotate about a rotational axis (2) and has friction plates (3), an output part (5) which can also rotate about the rotational axis (2), and a rocker damper (6) for coupling the input part (4) to the output part (5), wherein the rocker damper (6) further has a first flange region (7) which is connected to the input part (4), a second flange region (8) which can rotate about the rotational axis (2) relative to the first flange region (7) within a limited angular range and which is connected to the output part (5), and two flange regions (7, 7) which are each connected to the two flange regions (7) by a connecting rod arrangement (9, 10), 8) -intermediate pieces (11a, 11b) coupled in a movable manner, and wherein one spring unit (12) co-acts with the linkage arrangement (9, 10) in the following manner: when the flange regions (7, 8) are twisted relative to one another, a relative movement of the intermediate parts (11a, 11b) towards one another is prevented by the spring unit (12), wherein a friction device (13) is arranged inside or outside the spring element (14) of the spring unit (12) and acts in such a way that: in a first relative movement region of the intermediate pieces (11a, 11b), a frictional force that prevents a relative movement of the intermediate pieces (11a, 11b) is generated by the friction device (13) and is higher than a frictional force generated in a second relative movement region of the intermediate pieces (11a, 11b) that is offset from the first movement region. The invention also relates to a friction clutch having the clutch disk (1).)

1. Clutch disk (1) for a friction clutch of a motor vehicle, having an input part (4) which can be rotated about a rotational axis (2) and has friction plates (3), an output part (5) which can also be rotated about the rotational axis (2), and a rocker damper (6) for coupling the input part (4) to the output part (5), wherein the rocker damper (6) further has a first flange region (7) which is connected to the input part (4), a second flange region (8) which can be rotated about the rotational axis (2) relative to the first flange region (7) within a limited angular range and which is connected to the output part (5), and two intermediate parts (11a ) which are movably coupled to the two flange regions (7, 8) by means of a connecting rod arrangement (9, 10), respectively, 11b) Wherein a spring unit (12) and the connecting rod device (9, 10) act together in the following way: when the flange regions (7, 8) are twisted relative to each other, a relative movement of the intermediate pieces (11a, 11b) towards each other is prevented by the spring unit (12), characterized in that a friction device (13) is arranged inside or outside the spring element (14) of the spring unit (12) and acts in such a way that: in a first relative movement region of the intermediate pieces (11a, 11b), a frictional force that prevents a relative movement of the intermediate pieces (11a, 11b) is generated by the friction device (13) and is higher than a frictional force generated in a second relative movement region of the intermediate pieces (11a, 11b) that is offset from the first movement region.

2. The clutch driven disc (1) according to claim 1, characterized in that the spring element (14) sandwiched between the first intermediate piece (11a) and the second intermediate piece (11b) is designed as a helical compression spring.

3. The clutch driven disc (1) according to claim 1 or 2, characterized in that the friction means (13) are arranged radially outside the spring element (14) with respect to the longitudinal extension of the spring element (14) or radially inside the spring element (14) with respect to the longitudinal extension of the spring element (14).

4. A clutch disk (1) according to one of claims 1 to 3, characterized in that the friction device (13) has a first friction element (15) which is fixed to the first intermediate part (11a) and a second friction element (16) which is fixed to the second intermediate part (11b) and interacts with the first friction element (15) in a frictionally engaged manner via a first movement region of the intermediate parts (11a, 11 b).

5. Clutch driven plate (1) according to claim 4, characterized in that the first friction element (15) is of rigid design, viewed in the transverse direction of the spring element (14), and the second friction element (16) is deformable relative to the first friction element (15) in the transverse direction of the spring element (14).

6. The clutch driven disc (1) according to claim 4 or 5, characterized in that the second friction element (16) has at least one friction arm (17) which is deformable in the transverse direction of the spring element (14) and which bears against a side face (18) of the first friction element (15) in a first region of relative movement of the intermediate pieces (11a, 11 b).

7. The clutch driven disc (1) according to claim 6, characterized in that the side faces (18) of the first friction elements (15) taper in diameter in the direction of the second intermediate piece (11 b).

8. The clutch driven disc (1) according to one of claims 4 to 7, characterized in that the second friction element (16) is designed as a journal or a sleeve.

9. The clutch driven disc (1) according to any one of claims 4 to 8, characterized in that the friction elements (15, 16) are mutually coordinated in such a way that: they are arranged in a spaced-apart manner in a second relative movement region of the intermediate pieces (11a, 11 b).

10. Friction clutch for a motor vehicle drive train, with a pressure plate and a clutch disk (1) according to one of claims 1 to 9, which can be connected to the pressure plate in a frictionally engaged manner.

Technical Field

The invention relates to a clutch disk for a friction clutch of a motor vehicle (for example a car, truck, bus or other commercial vehicle), having an input part which can be rotated about a rotational axis and has friction linings, an output part which can also be rotated about a rotational axis, and a rocker arm damper for coupling the input part to the output part, wherein the rocker arm damper further has a first flange region which is connected to the input part, a second flange region which can be rotated about the rotational axis relative to the first flange region within a limited angular range and is connected to the output part, and two intermediate parts which are movably coupled to the two flange regions by means of a connecting rod arrangement, and wherein a spring unit interacts with the connecting rod arrangement in such a way that, namely: when the flange regions are twisted relative to one another, a relative movement of the intermediate pieces towards one another is prevented/supported by the spring unit. The invention further relates to a friction clutch for a drive train of a motor vehicle, having a pressure plate and a clutch disk which can be connected to the pressure plate in a frictionally engaged manner.

Background

Such background art is well known. For example, DE 102015211899 a1 discloses a torsional vibration damper with an input part arranged about a rotational axis and an output part opposite the input part which can rotate about the rotational axis to a limited extent against the action of a spring device.

Furthermore, a device for absorbing torque fluctuations is known from EP 1602854 a 2.

However, the embodiments known from the background art have found a disadvantage: in operation, a critical vibrational state may develop when natural resonance is inevitably transmitted. Rocker arm dampers do not work properly in this vibration range and, accordingly, cannot reliably suppress rotational imbalance of the internal combustion engine.

The object of the present invention is therefore to eliminate the disadvantages known from the background art and to realize a rocker arm damper, in particular in a clutch driven disk, which can achieve a damping capacity that is as constant as possible over the entire rotational speed range.

Disclosure of Invention

According to the invention, the solution to the task is: a friction device is arranged inside or outside the spring element of the spring unit and functions in such a way that: the friction force which prevents the relative movement of the intermediate piece is generated by the friction device in a first relative movement region of the intermediate piece and is higher than the friction force generated in a second relative movement region of the intermediate piece which is offset from the first movement region. The friction device is therefore dedicated to generating a position-dependent friction force.

In order to actively suppress the corresponding natural resonance, a frictional force is generated in a targeted manner by using a friction device, which converts the vibration energy into heat. As a result, rocker arm dampers are designed to be significantly more efficient. The hysteresis of the spring unit can be flexibly adjusted.

Further advantageous embodiments are claimed in the dependent claims and are explained in detail below.

The design of the spring element (of the spring unit) is particularly compact if it is designed as a helical compression spring, which is clamped between the first intermediate piece and the second intermediate piece.

It is likewise advantageous if the friction means are arranged radially outside the spring element with respect to the longitudinal extension/longitudinal axis of the spring element or radially inside the spring element with respect to the longitudinal extension/longitudinal axis of the spring element. The overall design of the clutch disk can also be particularly compact, depending on the available installation space.

The construction of the friction device is particularly simple if the friction device has a first friction element which is fastened to the first intermediate part and a second friction element which is fastened to the second intermediate part and interacts/abuts with the first friction element via the first movement region of the intermediate part in a frictionally engaged manner.

The manufacture of the first friction element can be particularly simple if the first friction element is of a rigid/non-deformable/non-flexible design, viewed in the transverse direction of the spring element (/ transverse to the longitudinal extension), and the second friction element can be (elastically) deformed relative to the first friction element in the transverse direction of the spring element.

In a particularly preferred manner, the second friction element is provided with at least one friction arm which is deformable in the transverse direction of the spring element and which (frictionally) bears against a side face (preferably a radially outer face) of the first friction element in the first relative movement region of the intermediate part. Preferably, the friction arms therefore bear against the side faces of the first friction element under the action of a radial pretensioning force.

It is particularly advantageous in this respect if the side of the first friction element tapers/decreases in diameter in the direction of the second intermediate piece. As a result, the friction force can be adjusted particularly flexibly as a function of the relative position of the intermediate piece in the first movement region.

As a further preference, the second friction element is designed as a journal or as a sleeve, so that it can be flexibly arranged in a space-saving manner radially inside the spring element (in the case of a journal) or radially outside around the spring element (in the case of a sleeve).

In addition, if the (first and second) friction elements are coordinated with each other in such a way that: it is also advantageous if they are arranged in a spaced-apart manner in a second relative movement region of the intermediate piece, i.e. if the friction means in the second relative movement region are deactivated (the friction force generated by the friction means is minimal/zero). This further improves the wear resistance of the friction device.

It is also advantageous if the friction element is formed from a plurality of longitudinal regions which differ in terms of the friction coefficient. As a particular preference, the different coefficients of friction are achieved by different materials. It is therefore particularly preferred if in particular the first friction element is composed of different materials in its region extending along the longitudinal axis (a plurality of adjacent longitudinal regions). It has proven to be particularly preferred if the longitudinal region of the second friction element consists of metal (for example steel) or of a polyamide-type plastic containing a mixture of carbon fibers, teflon and/or graphite. The friction force can thereby be adjusted particularly flexibly as a function of the first relative movement region of the intermediate piece.

The invention further relates to a friction clutch for a drive train of a motor vehicle, having a pressure plate and a clutch disk according to the invention, which can be connected to the pressure plate in a frictionally engaged manner and which corresponds to at least one of the above-mentioned embodiments.

In other words, a clutch driven disc with a rocker arm type damper having a hysteresis device (friction device) is realized according to the present invention. It is proposed that at least one spring (spring element) of the rocker arm damper is provided with a friction device for generating a friction force as a function of position, wherein the friction device is arranged inside or outside the spring.

The present invention will be described in detail below with reference to the accompanying drawings.

Drawings

Fig. 1 is a perspective view schematically showing a clutch driven plate according to a first embodiment of the present invention, in which the principle structure of a rocker arm type damper installed in the clutch driven plate can be clearly seen,

fig. 2 is a schematic sectional view of a region of the rocker arm shock absorber used in fig. 1, wherein the structure of the friction device which co-acts with the spring unit between the two intermediate members of the rocker arm shock absorber can be seen,

figure 3 is a perspective view of the area shown in figure 2 of the rocker arm shock absorber taken in a transverse direction,

fig. 4 is a sectional schematic view of a region of a rocker arm damper, showing how the rocker arm damper is mounted in a clutch driven disc according to a second embodiment, wherein the design of the friction device differs from that of the first embodiment in the following manner, namely: the friction means are then arranged outside the spring element of the spring unit, an

FIG. 5 is a perspective view, taken in a transverse direction, of the area shown in FIG. 4 of the rocker arm shock absorber.

The drawings are merely schematic in nature and are provided to aid in understanding the present invention. Like elements are provided with like reference numerals. It is also possible to freely combine different features of the different embodiments with each other.

Description of the reference numerals

1 Clutch driven disc 2 rotating shaft 3 input part 5 output part 6 swing arm type damper 7 first flange region 8 second flange region 9 first link means 10 second link means 11a first intermediate piece 11b second intermediate piece 12 spring unit 13 friction means 14 spring element 15 second friction element 16 second friction element 17 friction arm 18 side 19 friction disc support 20 hub 21 first link track 22 rolling element 23 second link track 24 third link track 25 longitudinal shaft 26 opening

Detailed Description

Fig. 1 shows the principle structure of a clutch disk 1 according to a first exemplary embodiment of the present invention. In operation, the clutch disk 1 is usually mounted in a friction clutch and is therefore effectively connected to a pressure plate, which is not shown here to ensure the overview. In general, the clutch disk 1 is connected with the pressure plate in a friction-fit manner when the friction clutch is in the closed position and is arranged in a freely rotatable manner relative to the pressure plate when the friction clutch is in the open position. Preferably, the friction clutch is in turn arranged in the motor vehicle drive train, i.e. directly between the internal combustion engine and the transmission of the drive train, as viewed in the direction of the torque flow.

The clutch disk 1 basically has an input part 4, an output part 5 and a rocker damper 6 which acts between the input part 4 and the output part 5. The input part 4 has a friction lining carrier 19 and a friction lining 3 which is mounted/fixed on the friction lining carrier 19. In particular, one friction disk 3 is arranged on each axial side of the friction disk carrier 19 (viewed along the rotational axis 2 of the clutch disk 1). The input section 4, which is designed as a whole in the form of a ring, is arranged in a rotatable manner about the axis of rotation 2. An output section 5 is arranged coaxially with the input section 4, also rotatably about the axis of rotation 2, in a radial direction inside the input section 4. The output part 5 usually forms a hub 20, which in operation is usually connected in a rotatable manner to a shaft of a drive train (for example a transmission input shaft of a transmission), which is not shown here for the sake of clarity. The rocker arm damper 6 is generally used to damp the rotational imbalance of the powertrain system. The rotational imbalance which occurs in most cases on the internal combustion engine side is usually introduced into the clutch disk 1 via the input part 4 and is damped in the transmission path from the input part 4 to the output part 5 by means of the rocker arm damper 6.

The rocker arm damper 6 has a first flange region 7 which is connected to the input part 4 in a rotationally fixed manner. In particular, the friction lining carrier 19 in this embodiment is mounted directly on the first flange region 7, i.e. riveted. The first flange region 7 is of substantially disk-shaped design. The rocker arm damper 6 also has a second flange region 8, which is connected to the output part 5 in a rotationally fixed manner. The second flange region 8, like the first flange region 7, is arranged coaxially thereto in a rotatable manner about the axis of rotation 2. The two flange regions 7 and 8 are in principle coupled/connected to each other in a rotatable manner, but can be twisted relative to each other about the axis of rotation 2 in the direction of rotation within a limited angular range.

The two flange regions 7 and 8 are coupled to one another in a movable/rotatable manner via two intermediate pieces 11a, 11 b. The two intermediate pieces 11a, 11b are designed essentially as identical parts and are arranged in a manner movable relative to each other in the radial direction of the axis of rotation 2. The two intermediate pieces 11a, 11b are offset with respect to one another by approximately 180 ° about the axis of rotation 2 in the direction of rotation. In the same way, the respective (first and second) intermediate pieces 11a and 11b are connected movably to the first flange region 7 and the second flange region 8 via the connecting rod arrangements 9, 10, respectively.

The first connecting rod means 9 serve to couple the first flange region 7 with the intermediate pieces 11a and 11b, respectively. In fig. 1, the first linkage 9 can be seen on the side of the two first linkage tracks 21 inserted into the intermediate pieces 11a, 11b and on the side of the two rolling bodies 22 each movably supported in one first linkage track 21. In addition, the rolling bodies 22 of the first connecting rod arrangement 9, which are assigned to the first connecting rod path 21, are also supported in the first flange region 7.

In fig. 1, the second connecting rod arrangement 10 for movably coupling the intermediate pieces 11a, 11b with the second flange region 8 is shown on the side of the second connecting rod path 23 inserted into the second flange region 8. The other rolling element 22 is movably supported in a second connecting rod path 23. The rolling bodies 22 are also supported in a movable manner in a third connecting rod path 24 which is inserted into the intermediate parts 11a, 11 b. The intermediate pieces 11a, 11b can thus be coupled to the flange regions 7, 8 via the connecting rod arrangements 9, 10 in such a way that: in operation, when the flange regions 7, 8 are twisted relative to one another, the intermediate pieces 11a, 11b are moved relative to one another in the circumferential direction and in the radial direction according to the embodiment of the connecting rod paths 21, 23, 24. In particular, the intermediate pieces 11a, 11b move in the radial direction inwards, segment by segment (in a first relative movement direction) when the flange regions 7, 8 are twisted relative to one another in a first (relative) direction of rotation, and move in the radial direction outwards, segment by segment (in a second relative movement direction opposite to the first direction of rotation), and thus move away from one another when the flange regions are twisted relative to one another in a second relative direction of rotation opposite to the first direction of rotation.

The spring unit 12 will act on the intermediate pieces 11a, 11 b. The spring unit 12 may be sandwiched (in radial direction) between the intermediate pieces 11a, 11b in such a way that: which prevent a relative movement of the intermediate pieces 11a, 11b with respect to each other in a first direction of movement and support a relative movement with respect to each other in a second direction of movement. In this embodiment, the spring unit 12 has two spring elements 14, of which only one of the two spring elements 14 is shown in fig. 1 to ensure the overview. An embodiment of two spring elements 14 can be further seen in fig. 2 and 3. Thus, in order to bias the intermediate pieces 11a, 11b outward in the radial direction, a total of two spring elements 14 are clamped between the intermediate pieces 11a, 11 b. The two spring elements 14 are of identical design and are supported in the same way on the intermediate pieces 11a, 11 b. The spring element 14 only differs in its position. Thus, the two spring elements 14 are arranged on opposite sides with respect to the rotation axis 2. Each spring element 14 is realized in the form of a helical pressure spring. The helical compression spring 14 extends linearly along a longitudinal axis 25 which extends in the circumferential direction as well as in the radial direction.

According to the invention, a friction device 13 is then provided in the spring unit 12, i.e. in each spring element 14. Therefore, a total of two friction devices 13 are provided in the spring unit 12. In the perspective view of fig. 1, the respective friction device 13 can be seen particularly clearly through the clearance of the two spring elements 14. The friction device 13 influences the relative movement of the intermediate pieces 11a, 11b in principle in the following manner: it generates a higher friction force in a first relative movement area/movement path/movement section of the intermediate pieces 11a, 11b than in a second relative movement area/movement path/movement section of the intermediate pieces 11a, 11b arranged axially offset/adjacent to/connected to said first relative movement area. As shown in fig. 2, if the intermediate members 11a, 11b are moved close to each other in the radial direction and are moved in the first motion region, the friction force generated is higher than the friction force generated in the second motion region in which the intermediate members 11a, 11b are moved away from each other in the radial direction, compared to fig. 2.

In the first embodiment, the friction means 13 are arranged radially inside the spring element 14 (that is to say radially inside the longitudinal axis 25 of the spring element 14). The friction device 13 is formed by two friction elements 15, 16. As shown in fig. 2 and 3, the first friction element 15, which is designed as a journal, can be seen particularly clearly. Thus, the first friction element 15 is pin/journal-shaped. The first friction element 15 is of substantially rigid design. In this embodiment, the first friction element 15 is fixed/fixedly mounted on the first intermediate member 11 a. The first friction element 15 extends from the first intermediate piece 11a to the second intermediate piece 11 b. The second friction element 16 of the friction device 13 is fixed/fixedly mounted on the second intermediate piece 11 b. The second friction element 16 extends from the second intermediate member 11b to the first intermediate member 11 a. As shown in fig. 1, the second friction element 16 is generally substantially sleeve-like/realized in the form of a sleeve. The second friction element 16 is likewise arranged radially inside (relative to the longitudinal axis 25) the spring element 14, but radially outside the first friction element 15.

The second friction element 16 has a plurality of axial openings 26. The second friction element 16 thus forms a plurality of friction arms 17 which are deformable in the radial direction relative to the longitudinal axis 25. The friction arms 17 interact directly with the first friction elements 15 in the first relative movement region of the intermediate parts 11a, 11 b. For this purpose, the friction arm 17 is in frictional contact with a side face 18 (radially outer surface) of the first friction element 15 in the region of the relative movement of the intermediate pieces 11a, 11 b.

The first friction element 15 is basically designed in such a way that: when the intermediate pieces 11a, 11b are moved closer to each other in the radial direction, i.e. in the first direction of movement and in the first movement region, the friction forces generated between the friction elements 15, 16 continue to increase. This is due, on the one hand, to the side 18 of the first friction element 15 tapering in the direction of the second intermediate piece 11b and, on the other hand, to the design of the friction arms 17. The friction arms 17 are resiliently biased inwardly in the radial direction and thus bear against the side faces 18 in a radially inwardly biased state. As the movement of the intermediate pieces 11a, 11b towards each other in the first movement direction increases, the pressing force of the friction arm 17 on the first friction element 15 also increases, which in turn increases the friction accordingly.

Viewed in the axial direction, the first friction element 15 additionally has different longitudinal regions (not shown here further to ensure the overview) which have different coefficients of friction. Different coefficients of friction are created by different materials/material properties. The first friction element 15 is thus formed from a plurality of longitudinal regions of different materials in the axial direction relative to the longitudinal axis 25. For this purpose, for example, a first longitudinal region of the first friction element 15 is made of a first material and a second longitudinal region of the first friction element 15 is made of a second material. The material is for example a plastic material, such as polyamide, preferably reinforced with fibres. Alternatively or additionally, metallic materials, such as steel, can also be used as the material.

If the intermediate pieces 11a, 11b are moved away from each other in the radial direction, that is to say in the second direction of movement, relative to each other, the friction elements 15, 16 are spaced apart from each other when viewing fig. 2. Thus, the friction means 13 is disabled in a second movement region, which is connected to the first movement region, as seen along the relative movement path of the intermediate pieces 11a, 11b, and no (direct) friction forces are formed between the friction elements 15, 16.

In conjunction with fig. 4 and 5, a further second exemplary embodiment is shown, in both fig. 4 and 5 as in fig. 2 and 3, again only one region of the rocker arm damper 6 being shown for the sake of clarity. The remaining structure and operation principle of the clutch driven disc 1 equipped with the rocker arm type damper 6 described in the second embodiment correspond to those of the clutch driven disc 1 described in the first embodiment.

In fig. 4, it is shown that the respective friction means 13 are realized in a different manner from the first embodiment. At this time, either the first friction element 15 or the second friction element 16 is designed to be sleeve-shaped. The first friction element 15 is realized in the form of a rigid (non-deformable in radial direction) sleeve. The second friction element 16 in turn surrounds the first friction element 15 radially from the outside and bears against the side 18 of the first friction element 15 in the first relative movement region of the intermediate pieces 10a, 10 b. In addition, two friction elements 15, 16 are arranged radially outside the spring element 14. Thus, as shown in fig. 1 to 3, the first friction element 15 and the second friction element 16, although still arranged coaxially with the longitudinal axis 25, extend from the outside in a radial direction around the spring element 14. The side faces 18 of the first friction element 15 taper in the axial extension thereof toward the second intermediate piece 11 b.

In other words, in a torsional vibration damper of the rocker arm damper 6 type, the two intermediate elements ( intermediate pieces 11a, 11b) are displaced relative to each other in one direction (relative to the axial direction of the spring element 14) and synchronously operate the pressure spring (spring element 14) located therebetween. This relative axial movement is used to generate friction or hysteresis. The friction force or hysteresis is formed by a suitable shape of the friction elements 15, 16 depending on the torsion angle. The design of the friction points depends on the construction space. From the point of view of the volume of the torsional vibration damper 6, it is advantageous in some cases to surround/locate the friction points outside/inside the compression spring 14.

According to the invention, a torsional vibration damper 6 of the rocker-arm damper type is realized in the following manner: the two opposite intermediate elements 11a, 11b synchronously operate a pressure spring 14 located therebetween, wherein a first element (first friction element 15) connected to the first intermediate element 11a rubs against a second, resilient element (second friction element 16) connected to the other second intermediate element 11 b.

According to an advantageous aspect, the relative movement of the two intermediate elements 11a, 11b causes the elastic element 16 to be elastically deformed with respect to the first element 15. A radial excess between the elements 15, 16 results in a certain friction between the two elements 15, 16. From a further advantageous point of view, the shape of the first element 15 can be designed in such a way that: the first element 15 deforms the second element 16 by a certain excess amount according to the change in the axial position of the intermediate elements 11a, 11b relative to each other or according to the change in the torsion angle of the rocker arm damper 6, thereby generating a certain friction force or hysteresis. From a further advantageous point of view, the shape of the first element 15 can be designed in such a way that: the hysteresis is closed by bringing the two elements 15, 16 out of contact in accordance with the change in the axial position of the intermediate elements 11a, 11b relative to one another or in accordance with the change in the angle of torsion of the rocker arm damper 6. According to another advantageous aspect, the first element 15 is made of steel and/or of a polyamide-type plastic comprising carbon fibers, teflon or a graphite compound. According to another advantageous point of view, the first element 15 is composed of a combination of two or more portions (longitudinal zones) of different materials. The friction or hysteresis is formed by the different coefficients of friction (different longitudinal areas) depending on the angle of torsion. According to another advantageous point of view, the elements 15, 16 are arranged in the pressure spring 14. According to another advantageous point of view, the elements 15, 16 are arranged around the pressure spring 14.