CN112762137A

CN112762137A - Torsional damper and clutch disc

Info

Publication number: CN112762137A
Application number: CN202011131908.8A
Authority: CN
Inventors: E·霍夫曼; L·乔克希尔; M·温克勒; S·奥特; R·韦丁格; B·科布; A·基里安; P·葛斯特; T·辛德勒; A·库比什; D·布尔; K·比迪克
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2019-10-21
Filing date: 2020-10-21
Publication date: 2021-05-07
Anticipated expiration: 2040-10-21
Also published as: CN112762137B; DE102019216146A1

Abstract

The invention relates to a torsional vibration damper (210) and a clutch disc (200) with a torsional vibration damper (210), comprising at least one helical spring (240) and an input (220) with at least one first window opening (250-1) for receiving the helical spring (240). The first window opening (250-1) has a first step (232-1) extending radially inward for supporting the coil spring (240) on an outer periphery (252-1) of the first window opening. Furthermore, the torsional vibration damper (210) comprises an output (230) axially spaced from the input (220), the output having at least one second window opening (250-2) for receiving a helical spring (240). The second window opening (250-2) has a second step (232-2) extending radially inward for supporting the coil spring (240) on an outer periphery (252-2) of the second window opening.

Description

Torsional damper and clutch disc

Technical Field

The present invention relates to a torsional vibration damper and a clutch disc. In particular, but not exclusively, the invention relates to a torsional vibration damper and a clutch disc for a motor vehicle.

Background

The torsional vibration damper can be used, for example, in the drive train of a motor vehicle and in particular in the clutch disk of a motor vehicle.

In order to damp torsional vibrations, which are caused, for example, by the motor, the torsional vibration damper can have an input part and an output part which is rotatable relative to the input part and which is elastically coupled to one another. The input and output members may be coupled to each other, for example, by means of one or more helical springs which are compressed upon relative rotation of the input and output members. The input and output may each have a window opening for receiving a coil spring. When the helical springs are compressed, the spring ends of these helical springs on the outer circumference of the window opening may rub on the input and/or output. The frictional work generated in this case can lead to increased wear of the input, output and/or spiral spring and thus to a reduced service life of the torsional vibration damper.

From the prior art, it is not known to provide a solution for reducing the wear of the helical spring, the input element and/or the output element due to frictional work.

Disclosure of Invention

It is therefore conceivable as an object of the invention to reduce the wear of the helical spring, the input element and/or the output element due to frictional work.

This object is achieved according to various aspects of the present disclosure.

According to a first aspect, the invention relates to a torsional vibration damper comprising at least one helical spring, and an input having at least one first window opening for receiving the helical spring. The first window opening has a first stepped portion for supporting the coil spring on an outer periphery thereof, the first stepped portion extending radially inward. Furthermore, the torsional vibration damper comprises an output piece which is spaced apart from the input piece in the axial direction and is provided with at least one second window opening for receiving the spiral spring. The second window opening has a second stepped portion for supporting the coil spring on an outer periphery thereof, the second stepped portion extending radially inward.

The first and second window openings can extend in the axial direction through the input or through the output, so that the helical spring can be arranged in the first and second window openings. The spring ends of the helical spring can each lie against a side of the window opening in the circumferential direction. The helical spring can be compressed when the input part is rotated relative to the output part, wherein one of the spring ends is coupled to the input part, for example, and the spring end opposite in the circumferential direction is coupled to the output part.

For support in the radial direction, the helical spring can bear against a first step and a second step, which are arranged on the outer circumference of the first window opening of the input part or on the outer circumference of the second window opening of the output part, respectively. By abutting the first step and the second step, the helical spring and/or its spring end can be radially spaced from the outer circumference of the first window opening or the second window opening, which moves relative to the spring end during relative rotation, for example. In this way, for example, friction-related wear due to friction of the helical spring on the input part or on the output part can be avoided.

In several embodiments of the present invention, the first step portion may extend up to an end of the first window opening defining the first window opening in the first circumferential direction. Further, the second step portion may extend up to an end of the second window opening that defines the second window opening in a second circumferential direction opposite the first circumferential direction.

In the case of coil springs arranged tangentially to the circumferential direction, the coil springs can be brought into contact with the input part or with the output part, in particular at their spring ends on the outer circumference of the first and second window openings. In order to support the helical spring in the radial direction at, for example, opposite spring ends in the circumferential direction, the first step and the second step can each extend in the opposite circumferential direction, so that one of these steps correspondingly supports one of the spring ends in the radial direction.

In several embodiments of the invention, the second circumferential direction may correspond to a rotational direction of the input member relative to the output member in a towing operation of the torsional vibration damper, and the first circumferential direction may correspond to a rotational direction of the input member relative to the output member in a coasting operation of the torsional vibration damper.

In particular, in torsional vibration dampers for motor vehicles, for example, the drive torque of the motor can be introduced into the torsional vibration damper via the input element during a traction operation. In the coasting operation, a torque which is opposite to the drive torque and is decelerated, for example, caused by the motor resistance, can be introduced into the torsional vibration damper via the input element. Thus, the direction of rotation of the input member relative to the output member during a towing operation is opposite to the direction of rotation during a coasting operation, for example.

When the input part is rotated relative to the input part in the pulling direction, a spring end arranged in the first circumferential direction, which bears against the first step on the outer circumference of the first window opening, is coupled to the input part for compressing the helical spring. In addition, a spring end, which is arranged in the second circumferential direction and which bears against the second step on the outer circumference of the second window opening, is coupled to the output part for compressing the helical spring.

By supporting the spring ends radially on the first or second step, the spring ends can be held at a distance from the input or from the output, which rotates relative to these spring ends, during the pulling operation. Friction between the spring ends and the input and output members can thereby be avoided, at least during a pulling operation.

In several embodiments of the invention, the first step portion may extend in the circumferential direction over at least 30% of the extension of the first window opening over its outer circumference, and the second step portion may extend in the circumferential direction over at least 30% of the extension of the second window opening over its outer circumference.

When the torsional damper is operated in a coasting operation, the first step portion and the second step portion may move in the circumferential direction opposite to the spring end portion. The spring end can in this case be swept in the circumferential direction, for example, over a maximum of 30% of the extent of the first window opening or of the second window opening on its outer circumference. In order to avoid jamming of the spring end on a ridge (Schwelle) which delimits the first or second step in the circumferential direction, for example in a return movement (which is oriented opposite to the relative rotation in the sliding operation), the first and second step can therefore extend over at least 30% of the extension of the first or second window opening.

In some embodiments of the present invention, the first step portion may be connected with the input member in a material-fit manner; and the second step can be connected to the output part in a material-fit manner.

The input and output elements can each be embodied as a single piece, for example as a stamping. The stamping process for producing the input part and the output part can be adapted in such a way that the first step is formed in one piece with the input part and is therefore connected in a material-fitting manner, or the second step is formed in one piece with the output part and is therefore connected in a material-fitting manner.

This makes it possible to produce the input element and the output element cost-effectively and simply.

Alternatively, the first stepped portion may be welded or otherwise materially bonded to the input and the second stepped portion may be welded or otherwise materially bonded to the output.

In several embodiments, the second stepped portion may be arranged offset in the axial direction with respect to the spring axis of the coil spring, and the second stepped portion may have a slope in the axial direction.

The second step can be arranged, for example, offset in the axial direction with respect to the spring axis, so that the second step comes into contact with the helical spring in an axially offset manner with respect to the spring axis. Thereby, the coil spring can be supported in the radial direction and at least in the axial direction.

The second step portion may be inclined in the axial direction so as to provide a surface-shaped abutment surface between the coil spring and the second step portion abutting against the coil spring. The larger the contact surface, the less friction-related wear of the helical spring on the contact surface can be, for example.

Several embodiments further comprise at least one fixing element which engages into the helical spring in the circumferential direction and is arranged firmly in relation to the input in the axial direction.

The fastening element is arranged, for example, on one of the ends of the first window opening, which ends delimit the first window opening in the circumferential direction and which extends parallel to the spring axis into the helical spring.

In order to arrange the fixing element in a fixed manner in the axial direction relative to the input part, the fixing element comprises, for example, one or more pin portions which bear against the input part on opposite sides in the axial direction. The fixing element can thereby be supported in the axial direction on the input part by means of the pin.

Axial displacement of the helical spring, which is caused, for example, by an axial force generated when the helical spring is compressed, can be prevented or at least reduced by the fixing element. Thereby, for example, wear of the helical spring caused by axial displacement of this helical spring is reduced.

In several embodiments of the invention, the outputs may comprise a first output and a second output, the first and second outputs being arranged on opposite sides of the input in the axial direction.

The first output element and the second output element can be connected to one another, for example, in a rotationally fixed manner. Furthermore, a second window opening with a second step can be introduced into the first output part and the second output part, so that the helical spring can extend in the axial direction through the first output part and the second output part. The spring end of the coil spring arranged in the second circumferential direction may be supported on the second step portions of the first and second outputs in the radial direction with respect to the distance from the outer periphery of the first window opening.

In the case where the coil spring and the first and second outputs are arranged symmetrically to the input in the axial direction, it is possible to achieve that the coil spring, when compressed, is subjected to a pressure load that is symmetrical with respect to the spring axis in the circumferential direction. This may, for example, prevent the helical spring from deforming in the axial direction during compression, which may increase wear of the torsional vibration damper.

According to a second aspect, the invention relates to a clutch disc comprising a torsional vibration damper according to the above set forth. Further, the clutch disc includes: a friction lining connected in a rotationally fixed manner to the input part of the torsional vibration damper; and a hub which is connected in a rotationally fixed manner to the output of the torsional vibration damper.

In order to couple the clutch disk to the drive side, a pressure can be applied to the friction linings in the axial direction in order to generate a friction torque between the drive-side component (e.g. the flywheel) and the friction linings. The friction torque can be used to introduce a drive torque or a deceleration torque of the motor into the clutch disk, for example.

The torque introduced into the clutch disk can be transmitted from the friction linings to the input part and from the torsion damper to the output part via the helical spring. The hub may have an external toothing in order to be able to be coupled with the output. The hub can have a rotational play in the circumferential direction relative to the output part. After overcoming the rotational play, the output element can transmit the torque introduced into the clutch disk to the hub. The hub may have an internal toothing in order to be able to be coupled to a driven shaft, for example for driving a motor vehicle.

During driving operation, the centrifugal force pressing the coil spring radially outward can act on the clutch disc and the torsional damper. With the above-described embodiment of the torsional vibration damper, for example, friction of the helical spring on the outer circumference of the first or second window opening can be avoided during a relative rotation in the pulling direction.

This reduces wear of the clutch disk, for example, and thus increases the service life of the clutch disk.

Drawings

Several examples of embodiments of the invention will be described in detail below, by way of example only, with reference to the accompanying drawings. In the drawings:

figure 1a shows a side view and a cross-sectional illustration of a conventional clutch disc having a conventional torsional vibration damper;

figure 1b shows a side view and a cross-sectional illustration of a conventional clutch disc with a conventional torsional vibration damper in case of relative rotation;

figure 2a shows a side view of a clutch disc with a torsional vibration damper in a relative rotational condition in a towing operation;

figure 2b shows a side view of a clutch disc with a torsional vibration damper in relative rotation in a coasting operation;

fig. 3 shows a graph for demonstrating the friction work of the helical spring of the torsional damper;

figure 4a shows a first cross-sectional representation and a second cross-sectional representation of a clutch disc with a fixing element; and

fig. 4b shows an embodiment of the fixing element.

Detailed Description

Various embodiments are now described in more detail and with reference to the accompanying drawings, in which several embodiments are shown.

While the embodiments may be modified and changed in various ways, the embodiments are illustrated by way of example in the drawings and are described in detail herein. It should be understood, however, that there is no intention to limit the embodiments to the forms disclosed, but on the contrary, the embodiments are intended to cover all functional and/or structural modifications, equivalents, and alternatives falling within the scope of the invention.

Fig. 1a and 1b show a conventional clutch disc 100 with a conventional torsional vibration damper 110 in a side view (left side) and a sectional illustration in section in the axial direction (right side), respectively. In fig. 1b, the input 120 has a relative rotation with respect to the output 130. In contrast, in fig. 1a, the input member 120 and the output member 130 do not rotate relative to each other.

The output 130 may, for example (as shown here), comprise two cover plates, each arranged on axially opposite sides of the input.

The input element 120 is connected in a rotationally fixed manner to the friction lining 102 in order to be able to be coupled to a drive-side component (not shown here) and, for example, to be able to introduce a drive torque into the clutch disk 100 and into the torsional vibration damper 110.

In order to elastically couple the input 120 with the cover 130, the conventional torsional vibration damper 110 comprises at least one helical spring 140, of which only the spring end 142 is shown in fig. 1a and 1b, in order to and to show the arrangement of the helical spring in the window opening 150-1 of the input 120 and the window opening 150-2 of the output 130. Other conventional clutch discs and torsional dampers may have other, e.g. rotationally symmetrically arranged, window openings 150-1 and 150-2 for arranging a plurality of helical springs.

The spring ends 142 of the helical springs are arranged in the circumferential direction such that they can be coupled with the input 120 and/or the output at the ends of the window openings 150-1 and 150-2 defined in the circumferential direction.

As can be seen on the right side of fig. 1a, the helical spring 140 and its spring end 142 can abut against a support section 132 arranged on the outer circumference of the window opening 150-2. Thus, the coil spring 140 may be spaced apart from the outer circumference of the window opening 150-1 of the input member 120 in the radial direction.

In case of relative rotation, as can be seen in fig. 1b, the radial spacing of the helical spring 140 and its spring end 142 from the periphery of the window opening 150-1 decreases. Thus, in the event of relative rotation, friction may be generated between at least one of the spring ends 142 and the support section 132 and/or the outer periphery of the window opening 150-1 abutting that spring end. The friction may, for example, lead to increased wear of the helical spring 140, its spring end 142 and/or the output 130 on the support section 132.

It is therefore conceivable as an object of the invention to reduce the wear of the helical spring, the input element and/or the output element caused by friction.

An exemplary embodiment of the invention is explained with the aid of fig. 2a and 2 b.

Fig. 2a and 2b show a torsional vibration damper 210, in which the input element 220 and the output element 230 have opposite relative rotations with respect to one another in fig. 2a and 2 b. In a traction operation, if a driving torque, for example generated by a motor, is introduced into the clutch disc 200 and the torsional damper 210, there is a relative rotation, for example as illustrated in fig. 2 a. In a coasting operation, if a deceleration torque, for example caused by the motor, is introduced into the clutch discs 200 and the torsional damper 210, there is a relative rotation, for example illustrated in fig. 2b, which is opposite to that in a traction operation.

As shown in fig. 2a and 2b, the input element 220 of the torsional vibration damper 210 can be embodied, for example, as a driver disk (Mitnehmerscheibe) and the output element 230 can be embodied, for example, as a cover plate of the clutch disk 200. Cover plate 230 is axially disposed relative to drive plate 220. For coupling with the drive-side component, the drive disk 220 can be connected to the friction lining 202 in a rotationally fixed manner. The cover plate 230 can be connected to a hub (not shown here) in a rotationally fixed manner, for example, in order to be able to transmit the torque transmitted by the clutch disk 200 to a component coupled to the hub.

The drive disk 220 includes at least one first window opening 250-1 and the cover plate 230 includes a second window opening 250-2 for receiving at least one coil spring 240 that may resiliently couple the drive disk 220 and the cover plate 230 to each other. In fig. 2a and 2b, only spring end 242-1 and spring end 242-2 are shown, respectively, in order to show the arrangement of the helical spring 240, the turns of which can be arranged, for example, in the circumferential direction between spring end 242-1 and spring end 242-2.

In order to fix the helical spring 240 in the axial direction and/or to make the pressure load symmetrical when compressing the helical spring 240, a further cover plate (not shown here) may be arranged on the side of the drive plate 220 axially opposite the cover plate 230.

The coil spring 240 can be brought into contact in the radial direction at its spring ends 242-1 and 242-2 with the first step 232-1 of the drive disk 220 or the second step 232-2 of the cover plate 230. The second step 232-2 of the second window opening can, for example, be inclined in the axial direction and come into abutment with the helical spring 240 in an axially offset manner with respect to the spring axis. The spring axis here describes, for example, a connecting line of the center points of the spring rings.

In a pulling operation, spring end 242-1 and spring end 242-2 are pressed toward each other in the circumferential direction against the restoring force of coil spring 240. In the case of relative rotation in the pulling operation, the spring end 242-1 is in abutment with the drive disk 220 at the end of the first window opening 250-1 defined in the first circumferential direction. The spring end 242-2 is in abutment with the cover plate 230 at the end of the second window opening 250-2 defined in the second circumferential direction. Thus, the spring end 242-1 and the spring end 242-2 have, for example, negligible wear or ideally no relative movement with respect to the first step 232-1 or the second step 232-2, respectively, against which the spring end 242-1 and the spring end 242-2 abut. Thus, during a towing operation, friction-related wear of the drive plate 220, the cover plate 230 and/or the coil spring 240 and/or the spring ends 242-1 and 242-2 of the coil spring may be negligibly small relative to other wear mechanisms within the torsional vibration damper 210.

By placing spring ends 242-1 and 242-2 in abutment with first step 232-1 or with second step 232-2, these spring ends are radially spaced from outer peripheries 252-1 and 252-2 of cover plate 230 or drive plate 220, respectively, which are movable relative to spring ends 242-1 and 242-2. In contrast to conventional torsional vibration dampers 110, friction-related wear due to friction on the drive disk 220 or on the cover plate 230, which is movable relative to the spring end 242-1 and the spring end 242-2, can thus be avoided during towing operation.

In a sliding operation (as shown in fig. 2 b), the end of the second window opening 250-2 defined in the second circumferential direction forms, for example, a stop for the spring end 242-1 and the cover plate 230, whereby the spring end 242-1 can be moved in the circumferential direction relative to the first step 232-1 in the event of relative rotation in the sliding operation. Likewise, the end defining the first window opening 250-1 in the first circumferential direction forms, for example, a stop for the spring end 242-2 and the drive disk 220, whereby the spring end 242-2 can be moved in the circumferential direction relative to the second step 232-2 in the event of relative rotation in the sliding operation.

Thereby, a frictional work between the spring end 242-1 and the first step 232-1 on the one hand and the spring end 242-2 and the second step 232-2 on the other hand can be generated in the coasting operation. The frictional work consumed causes the coil spring 240, the cover plate 230 and the driving disk 220 to be worn in the sliding operation.

The diagram of fig. 3 illustrates exemplary frictional work that can be dissipated in the conventional torsional vibration damper 110 and the torsional vibration damper 210 depending on the load state (coasting operation, traction operation), for example. For this purpose, the friction work is depicted on the vertical axis 350 relative to the angle of rotation. The rotation angle is depicted along a horizontal axis 340. The curve of the angle of rotation depicted on the horizontal axis 340 describes, for example, the course of the angle of rotation with the coil spring 240 compressed and subsequently relaxed. The frictional work described herein relates to frictional work between the

coil spring

140 or 240 and a component (e.g., the support section 132, the first step 232-1, and/or the second step 232-2) that radially abuts the

coil spring

140 or 240.

Fig. 3 illustrates exemplary frictional work 310 that may be dissipated while the conventional torsional damper 110 is in traction operation. Due to the symmetrical design of the window openings 150-1 and 150-2, it can be assumed that the frictional work of the conventional torsional damper 110 in a coasting operation is equal to the frictional work 310 in a towing operation.

According to the graph of fig. 3, the friction work 320 of the torsional vibration damper 210 in coasting operation exceeds the friction work 310 of the conventional torsional vibration damper 110 in traction operation.

Furthermore, the graph illustrated in fig. 3 gives the friction work 330 that may be dissipated in the pulling operation of the torsional vibration damper 210, for example. The friction work 330 is here significantly less than the friction work 310 and the friction work 320.

Thus, the sum of the

frictional work

320 and 330 may be less than the sum of the frictional work of the conventional torsional damper 110 during coasting and towing operations. Thus, the torsional vibration damper 210 or clutch disc 200 may have less friction related wear relative to the conventional torsional vibration damper 110 or the conventional clutch disc 100.

In particular commercial vehicles (NKW) are operated in traction operation more frequently than in coasting operation, for example. For this reason, the friction-related wear of the torsional vibration damper 210 or the clutch disk 200 may be smaller, for example, in NKW, than the friction-related wear of the conventional torsional vibration damper 110 or the conventional clutch disk 200.

Figure 4a shows an embodiment of the clutch disc 200 in a first cross-sectional illustration (above) in a cross-section along section line G-G and in a second cross-sectional illustration (below) in a cross-section along section line F-F.

The clutch plate 200 includes, for example, a driver plate 220 having a plurality of first window openings 250-1 for receiving an equal number of coil springs 240. On axially opposite sides of the drive disk 220, in each case one of the cover plates 230 is arranged, which has a corresponding number of second window openings 250-2 for receiving the helical springs 240.

The second step 232-2 of the second window opening 250-2 correspondingly bears against the outer circumference of the coil spring 240 in an axially offset manner with respect to the spring axis. Thus, the spring end 242-2 of the coil spring 240 is, for example, arranged firmly in the axial direction or fastened in the axial direction with respect to the cover plate 230 and the driver plate 220.

On the opposite spring end 242-1, the first step 232-1 of the first window opening 250-1 respectively bears radially on the outside with respect to the spring axis against the helical spring 240. Thus, for example, axial securement of spring end 242-1 is not ensured so that spring end 242-1 may have an axial displacement when compressed.

To axially secure spring end 242-1, a securing element 260 may be used, for example. An embodiment for such a fixing element 260 is shown in fig. 4 b. Fig. 4b shows the fixing element in a perspective view in the circumferential direction (upper left), in an axial direction (upper right) and in a radial direction (lower right) and in an oblique view (lower left).

The fastening element 260 has, for example, a cylindrical holding section 262, the outer diameter of which is smaller than the inner diameter of the helical spring 240. The holding section 262 is arranged such that this holding section engages in the helical spring 240 in the circumferential direction, respectively.

Furthermore, the fixing element 260 has a plurality of pin portions 264. The pin portions 264 are arranged such that they bear against the drive plate 220 on axially opposite sides.

Thus, by means of the fixing element 260, the helical spring 240 can be fastened in particular in the axial direction, so that an axial displacement of the helical spring 240 is prevented or at least limited. Thereby, wear of the helical spring 240 and, for example, of the drive disk 220 due to friction when the spring end 242-1 is displaced axially can be at least reduced.

The securing element 260 may be released from the driving plate 220, for example, in the radial direction, so that the coil spring 240 can be controlled by the cover plate 230 or by the driving plate 220 by means of the securing element 260, depending on whether the clutch plate 200 is operated in a traction operation or a sliding operation.

Since the fastening element 260 is supported in the axial direction on the drive disk 220, rather than also on the cover plate 230 as is conceivable, it is possible to avoid the insertion process and the release process (Ein-und) of the coupling of the drive disk 220 to the fastening element 260 during the damping of torsional vibrations during a towing operation without the need for an insertion process and a release process (Ein-und) of the coupling of the drive disk 220 to the fastening element 260

)。

In order to fasten the inner springs 270 in the coil springs 240, the fastening elements 260 additionally each have a further retaining section 263, which engages in the respective inner spring 270 in the circumferential direction.

List of reference numerals

100 conventional clutch disc

102 friction lining

110 conventional torsional vibration damper

120 input piece

130 output element

132 support section

140 spiral spring

Spring end of 142 coil spring

150-1 Window opening

150-2 Window opening

200 clutch disc

202 Friction lining

210 torsional vibration damper

220 driving disk

230 cover plate

232-1 first step part

232-2 second step part

240 spiral spring

242-1 spring end

242-2 spring end

250-1 first Window opening

250-2 second Window opening

252-1 outer periphery of first window opening

252-2 outer periphery of second window opening

260 fixation element

262 holding section

263 additional holding section

264 pin part

270 inner spring

310 conventional torsional damper frictional work in traction operation

Friction work of 320 torsional damper in sliding operation

330 torsional damper friction work in traction operation

Claims

1. A torsional vibration damper (210), comprising:

at least one coil spring (240);

an input (220) having at least one first window opening (250-1) for receiving the coil spring (240), wherein the first window opening (250-1) has a first step (232-1) for supporting the coil spring (240) on an outer circumference (252-1) of the first window opening, the first step extending radially inward;

an output (230) axially spaced from the input (220), the output having at least one second window opening (250-2) for receiving the coil spring (240), wherein the second window opening (250-2) has a second step (232-2) for supporting the coil spring (240) on an outer periphery (252-2) of the second window opening, the second step extending radially inward.

2. The torsional vibration damper (210) of claim 1,

wherein the first step portion (232-1) extends up to an end of the first window opening (250-1) defining the first window opening (250-1) in a first circumferential direction; and is

The second step (232-2) extends up to an end of the second window opening (250-2) that defines the second window opening (250-2) in a second circumferential direction opposite the first circumferential direction.

3. The torsional vibration damper (210) of claim 2, wherein the second circumferential direction corresponds to a rotational direction of the input (220) relative to the output (230) in a towing operation of the torsional vibration damper, and the first circumferential direction corresponds to a rotational direction of the input (220) relative to the output (230) in a coasting operation of the torsional vibration damper (210).

4. Torsional vibration damper (210) of one of the preceding claims,

wherein the first step portion (232-1) extends in the circumferential direction over at least 30% of the extension of the first window opening (250-1) at its outer periphery (252-1); and is

Wherein the second step (232-2) extends in the circumferential direction over at least 30% of the extension of the second window opening (250-2) at its outer periphery (252-2).

5. Torsional vibration damper (210) of one of the preceding claims,

wherein the first step (232-1) is materially connected with the input member (220); and is

Wherein the second step (232-2) is connected to the output part (230) in a material-fit manner.

6. The torsional damper (210) as set forth in one of the preceding claims, wherein said second step (232-2) is arranged offset in the axial direction from the spring axis of said helical spring (240) and has a slope in the axial direction.

7. The torsional vibration damper (210) of one of the preceding claims, further comprising at least one fixing element (260), wherein the fixing element (260) is engaged into the helical spring (240) in a circumferential direction, and wherein the fixing element (260) is arranged securely in an axial direction with respect to the input (220).

8. The torsional vibration damper (210) of one of the preceding claims, wherein the output (230) comprises a first output and a second output, the first and second outputs being arranged axially on opposite sides of the input (220).

9. A clutch disc (200) comprising:

the torsional vibration damper (210) of claims 1-8;

a friction lining (202) which is connected in a rotationally fixed manner to an input (220) of the torsional vibration damper (210);

a hub connected in a rotationally fixed manner with an output (230) of the torsional vibration damper.