DE102022110528A1 - precise friction device for a torsional vibration damper - Google Patents

Abstract

A friction device (20) is provided for providing a friction torque within a torsional vibration damper, in particular a dual-mass flywheel (10), with a primary mass (12) rotatable about an axis of rotation for introducing a torque, one with an axial preload on an inside (32) of the primary mass (12) pressable sealing membrane (28) for sealing a receiving space (22) partially delimited by the primary mass (12), a friction ring (30) pressed between the sealing membrane (28) and the inside (32) of the primary mass (12) to provide a Friction surface for the friction torque, wherein the friction ring (30) is attached to the sealing membrane (28) in a substantially rotationally fixed manner, the friction ring (28) being guided on the sealing membrane (28) so that it can be relatively displaceably limited in the axial and/or in the radial direction. Due to the relative mobility of the friction ring (30), which is only fastened in a rotationally fixed manner with the sealing membrane (28), the contact pressure of the sealing membrane (28) can be kept constant even with low tolerance requirements, so that a friction torque that is precisely predetermined by the friction device (20) is possible.

Description

The invention relates to a friction device, with the help of which a deliberately intended friction torque can be provided in a torsional vibration damper of a drive train of a motor vehicle in order to avoid a resonance-related build-up of torsional vibrations in the torsional vibration damper.

Out of DE 10 2020 122 501 A1 a torsional vibration damper designed as a dual-mass flywheel with a friction device formed between a primary mass and a secondary mass is known, the friction device having a sealing membrane fastened to the secondary mass and a sliding ring which is firmly fastened to the sealing membrane and can be slid off the primary mass with friction.

There is a constant need to be able to specify the friction torque provided by a friction device as precisely as possible.

It is the object of the invention to show measures that enable a friction torque that is precisely specified by a friction device.

The problem is solved by a friction device with the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the following description, which can each represent an aspect of the invention individually or in combination.

One embodiment relates to a friction device for providing a friction torque within a torsional vibration damper, in particular a dual-mass flywheel, with a primary mass that can be rotated about an axis of rotation for introducing a torque, a sealing membrane that can be pressed with an axial preload on an inside of the primary mass for sealing a receiving space partially delimited by the primary mass, a friction ring pressed between the sealing membrane and the inside of the primary mass to provide a friction surface for the friction torque, the friction ring being attached to the sealing membrane in a substantially rotationally fixed manner, the friction ring being guided on the sealing membrane so that it can be relatively displaced in the axial and/or radial direction .

Due to the essentially non-rotatable attachment of the friction ring to the sealing membrane, a relative rotation of the friction ring relative to the sealing membrane is avoided. This prevents wear and/or damage to the sealing membrane. It was recognized that high temperatures can occur due to friction on a friction surface of the friction ring, particularly with a high contact pressure applied by the sealing membrane and high relative speeds. However, the sealing membrane has a significantly smaller material thickness compared to the primary mass, which makes it more difficult to dissipate heat and cool the friction point. Because a friction-affected relative rotation of the friction device occurs essentially exclusively between the friction ring and the primary mass, significantly better heat dissipation can take place via the primary mass compared to the sealing membrane. A temperature-related impairment of the friction properties of the friction device can thereby be avoided. At the same time, damage to the sealing membrane can be avoided through effects comparable to friction welding. The intentionally intended friction torque provided by the friction device can thereby be specified more precisely and can be better kept constant over the service life.

At the same time, a movement-proof attachment of the friction ring to the sealing membrane is avoided. A relative rotation is avoided by the rotation-proof coupling of the friction ring to the sealing membrane, but a relative movement of the friction ring relative to the sealing membrane in the radial direction and/or axial direction is permitted to a limited extent. This takes advantage of the knowledge that in order to avoid temperature-related damage to the sealing membrane as a result of frictional heat on the friction ring, it is already sufficient to minimize or even eliminate a relative rotation of the friction ring to the sealing membrane. Since at least a slight relative mobility of the friction ring to the sealing membrane is consciously permitted, the friction ring can automatically align itself relative to the sealing membrane on the primary mass. This can, for example, ensure that the friction ring automatically centers itself on the primary mass in the radial direction and/or automatically compensates for an inclination of the inside of the primary mass, caused for example by manufacturing tolerances and/or assembly tolerances, to a radial plane running orthogonally to an axis of rotation of the friction device. Due to the relative mobility of the friction ring relative to the sealing membrane in the radial and/or axial direction, an automatic compensating movement of the friction ring does not result in the sealing membrane being elastically deformed during the compensating movement. This can ensure that the spring properties of the sealing membrane remain essentially unchanged, so that in particular the contact pressure of the sealing membrane, which is essential for the frictional torque of the friction device, remains essentially constant even when the friction ring experiences a compensating movement. Through the relative Mobility of the friction ring, which is only fastened in a rotationally fixed manner with the sealing membrane, the contact pressure of the sealing membrane can be kept constant even with low tolerance requirements, so that a friction torque that is precisely predetermined by the friction device is possible.

The sealing membrane can be produced in particular from a sheet metal by punching and forming. The sealing membrane can have openings in a radially inner fastening area for fastening with a secondary mass, in particular an output flange of the secondary mass. The sealing membrane can have a radially outer force edge, via which the friction ring can be pressed against the inside of the primary mass. The sealing membrane can in particular be designed comparable to a plate spring and, by elastically changing its conicity, provide a spring force pointing in the axial direction in order to generate the axial preload.

The primary mass can have a U-shaped cross-section that is open radially inwards, so that the primary mass can delimit a large part of the receiving space, the sealing membrane being able to be arranged at least partially between the axial sides of the primary mass that face one another and the friction disk against one of the axial sides presses. In the area of contact with the friction ring, the primary mass can have an axial thickness D, for which, in relation to the material thickness d of the sealing membrane, 2.0 ≤ D/d ≤ 100.0, in particular 5.0 ≤ D/d ≤ 50.0 and preferably 10.0 ≤ D/d ≤ 25.0 can apply. The primary assembly is made in particular of steel, but can also be made of cast iron.

The friction ring can in particular be made of a plastic material. Preferably, the friction ring is coated on the axial side facing the inside of the primary mass with a material selected with regard to its friction properties.

In particular, it is provided that the inside of the primary mass is designed to be essentially immovable in the axial direction and an extent of the axial displaceability of the friction ring is essentially determined only by an elastic deformability of the sealing membrane in the axial direction. The primary mass can be designed to be essentially rigid and non-deformable under the contact pressure forces applied by the sealing membrane, so that the inside cannot yield in the axial direction. As a result, the axial mobility of the friction ring is only determined by the elasticity of the sealing membrane acting on the friction ring in the axial direction. To compensate for an inclination of the inside of the primary mass, the friction ring can use the spring travel provided by the sealing membrane in the axial direction.

Preferably, the friction ring is fastened to the sealing membrane in a rotationally fixed manner and displaceably in the axial and/or radial direction via a web which is axially displaceably guided between two tangential stops. The web can at most be accommodated with a clearance fit between the tangential stops and thus essentially non-rotatable. However, the web can slide in the radial direction and/or in the axial direction on the respective tangential stop. It is possible here that the web is formed by the friction ring and the tangential stops by the sealing membrane or the web by the sealing membrane and the tangential stops by the friction ring.

Particularly preferably, the sealing membrane has at least one web bent in the axial direction, the web being inserted in an axially and/or radially displaceable manner into an associated receiving pocket of the friction ring in a substantially rotationally fixed manner. The bent web can be formed cost-effectively in a punching and forming process that is already provided for producing the sealing membrane. In the case of the friction ring produced, for example, by plastic injection molding, the pocket can already be provided during the original molding process. The production of the friction device can therefore be carried out particularly cost-effectively.

Additionally or alternatively, it is provided that the sealing membrane has a through opening, wherein the friction ring has a web which is inserted in the through opening in a substantially rotationally fixed and axially and/or radially displaceable manner. The through opening can be produced cost-effectively in a punching process that is planned anyway during the production of the sealing membrane. In the case of the friction ring produced, for example, by plastic injection molding, the web protruding in the axial direction from the remaining friction ring can already be provided during the original molding process. The production of the friction device can therefore be carried out particularly cost-effectively.

In particular, the web of the friction ring has a captive device, in particular a retaining clip, for retaining the web in the through opening. The friction ring can be loosely clipped into the through opening of the sealing membrane using the retaining clip formed at a free end of the web. This can prevent the friction ring from falling off, for example during assembly.

Preferably, the sealing membrane has one essentially provided in a radial plane Disc area and a ring area that protrudes radially on the outside from the disc area to the radial plane. The sealing membrane can therefore essentially have the three-dimensional shape of a disc spring.

Particularly preferably, the friction ring is at least partially, in particular completely, fastened in the ring area with the sealing membrane. The disc area is therefore essentially unaffected by the friction ring. The axial flexibility of the sealing membrane, which is essentially determined by the disk area and thus the spring characteristic and the contact pressure of the sealing membrane, is therefore easily adjustable in advance and is essentially not affected by the fastening technology of the friction ring to the sealing membrane.

A further embodiment relates to a torsional vibration damper, in particular a dual-mass flywheel, for damping torsional vibrations between a drive shaft of a motor vehicle engine and a transmission input shaft of a motor vehicle transmission, with a primary mass for introducing a torque, a secondary mass that can be rotated to a limited extent relative to the primary mass via an energy storage element, in particular an arc spring, for transmitting the torque, wherein the primary mass and the secondary mass at least partially delimit a receiving space for, in particular lubricated, receiving of the energy storage element, and a friction device formed between the secondary mass and the primary mass, which can be designed and further developed as described above. The torsional vibration damper can in particular be designed and further developed as explained above with reference to the friction device. Due to the relative mobility of the friction ring, which is only fastened in a rotationally fixed manner with the sealing membrane, the contact pressure of the sealing membrane can be kept constant even with low tolerance requirements, so that a friction torque that is precisely predetermined by the friction device is possible for the torsional vibration damper.

The primary mass and the secondary mass, which is rotatably coupled to the primary mass in a limited manner via the energy storage element, which is designed in particular as an arc spring, can form a mass-spring system which can dampen rotational irregularities in the speed and torque of the drive power generated by a motor vehicle engine in a certain frequency range. Here, the mass moment of inertia of the primary mass and/or the secondary mass as well as the spring characteristic of the energy storage element can be selected such that vibrations in the frequency range of the dominant engine orders of the motor vehicle engine can be dampened. The friction torque deliberately applied by the friction device can dampen a resonance-related build-up of torsional vibrations in the mass-spring system of the torsional vibration damper. The mass moment of inertia of the primary mass and/or the secondary mass can be influenced in particular by an attached additional mass. The primary mass can have a disk to which a cover can be connected, whereby a substantially annular receiving space for the energy storage element can be limited. The primary mass can, for example, strike tangentially on the energy storage element via impressions projecting into the receiving space. An output flange of the secondary mass can protrude into the receiving space and can abut tangentially on the opposite end of the energy storage element.

In particular, the sealing membrane is fastened with an output flange of the secondary mass protruding from the receiving space, with a sealing device for sealing the receiving space being provided on an axial side of the output flange pointing away from the sealing membrane between the output flange and the primary mass.

• 1: eine schematische Schnittansicht eines Teils eines Zweimassenschwungrads,
• 2: eine schematische perspektivische Draufsicht auf eine Dichtmembran des Zweimassenschwungrads aus 1 und
• 3: eine schematische perspektivische Draufsicht auf die Dichtmembran aus 2 mit montiertem Reibring.

The invention is explained below by way of example with reference to the accompanying drawings using preferred exemplary embodiments, whereby the features shown below can represent an aspect of the invention both individually and in combination. Show it:

• 1 : a schematic sectional view of part of a dual mass flywheel,
• 2 : a schematic perspective top view of a sealing membrane of the dual-mass flywheel 1 and
• 3 : a schematic perspective top view of the sealing membrane 2 with mounted friction ring.

The in 1 The torsional vibration damper shown using the example of a dual-mass flywheel 10 can be installed in the drive train of a motor vehicle in order to dampen rotational irregularities in the transmitted torque. For this purpose, the torsional vibration damper 10 has a primary mass 12, which can be rotated to a limited extent relative to a secondary mass 14 designed as an output flange. The primary mass has a mass part 16 which can be connected to a drive shaft and which provides a significant mass moment of inertia in the manner of a flywheel. In addition, the primary mass 12 has a cover 18 welded to the mass part 16 on an axial side. The mass part 16 and the lid 18 together form the primary mass 12, which delimits a receiving space 22, in which an energy storage element 24 designed as a bow spring or as a package of nested bow springs is arranged. The energy storage element 24 is guided in the circumferential direction on a sliding shell connected to the mass part 16. So that the energy storage element 24 can slide smoothly on the sliding shell even under the influence of centrifugal force, a lubricant, for example grease, can be provided in the receiving space 22. The receiving space 22 is sealed to the extent that the lubricant cannot escape from the receiving space 22 and/or contamination can enter. The receiving space 22 is sealed between the mass part 16 of the primary mass 12 and the secondary mass 14 via a sealing device 26. Between the secondary mass 14 and the cover 18 of the primary mass 12, a friction device 20 is provided, which has a sealing membrane 28 riveted to the secondary mass 14, which, with an axial preload, counteracts a friction ring 30 which is fastened in a rotationally fixed manner but can be moved to a limited extent in the radial and/or axial direction an inside 32 of the cover 18 of the primary mass 12 is pressed in order to impose a deliberate friction torque.

As in 2 is shown, the sealing membrane 28 has a fastening region 36 having openings 34 radially on the inside, from which a bent-connected disk region 38 protrudes radially outwards, from which in turn a beveled ring region 40 protrudes radially outwards, which forms a force edge of the sealing membrane shaped as a plate spring trains. Through openings 42 are formed within the ring area 40.

As in 3 is shown, a web 44 of the friction ring 30 can be inserted into the respective through opening 42, which can have a clear play in the through opening 42 in the radial direction, while a play in the circumferential direction through an edge of the through opening formed by tangential stops is very small, in particular minimal, is trained. In the exemplary embodiment shown, the web 44 has retaining clips 46 which surround the tangential stops. The retaining clips 46 effect a captive attachment of the friction ring 30 to the sealing membrane 28. Here, a clear play can be provided in the axial direction between the retaining clips 46 and a rear side of the sealing membrane 28 facing away from the friction ring 30, so that the friction ring is relative to the sealing membrane 28 is designed to be limitedly displaceable in the axial direction.

Reference symbol list

10

Dual mass flywheel

12

Primary mass

14

secondary mass

16

mass part

18

Lid

20

Friction device

22

Recording room

24

Energy storage element

26

Sealing device

28

Sealing membrane

30

Friction ring

32

inside

34

opening

36

Fastening area

38

disc area

40

Ring area

42

Passage opening

44

web

46

Retaining clip

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102020122501 A1 [0002]

Claims (10)

Friction device (20) for providing a friction torque within a torsional vibration damper, in particular a dual-mass flywheel (10), with a primary mass (12) which can be rotated about an axis of rotation for introducing a torque, which can be pressed with an axial preload on an inside (32) of the primary mass (12). Sealing membrane (28) for sealing a receiving space (22) partially delimited by the primary mass (12), a friction ring (30) pressed between the sealing membrane (28) and the inside (32) of the primary mass (12) to provide a friction surface for the frictional torque , wherein the friction ring (30) is attached to the sealing membrane (28) in a substantially rotationally fixed manner, characterized in that the friction ring (28) is guided on the sealing membrane (28) so that it can be relatively displaceably limited in the axial and / or in the radial direction. Friction device (20). Claim 1 , wherein the inside (32) of the primary mass (12) is essentially immovable in the axial direction and an extent of the axial displaceability of the friction ring (30) is essentially only determined by an elastic deformability of the sealing membrane (28) in the axial direction. Friction device (20). Claim 1 or 2 , wherein the friction ring (30) is fastened to the sealing membrane (28) in a rotationally fixed manner and displaceably in the axial and / or radial direction via a web (44) which is axially displaceable between two tangential stops. Friction device (20) according to one of the Claims 1 until 3 , wherein the sealing membrane (28) has at least one web bent in the axial direction, the web being inserted in an axially and/or radially displaceable manner into an associated receiving pocket of the friction ring (30) in a substantially rotationally fixed manner. Friction device (20) according to one of the Claims 1 until 4 , wherein the sealing membrane (28) has a through opening (42), wherein the friction ring (30) has a web (44) which is inserted in the through opening (42) in a substantially rotationally fixed and axially and/or radially displaceable manner. Friction device Claim 5 , wherein the web (44) of the friction ring (30) has a captive device, in particular a retaining clip (46), for retaining the web (44) in the through opening (42). Friction device according to one of the Claims 1 until 6 , wherein the sealing membrane (28) has a disk region (38) provided essentially in a radial plane and an annular region (40) which protrudes at an angle radially on the outside from the disk region (38) to the radial plane. Friction device Claim 7 , wherein the friction ring (30) is at least partially, in particular completely, fastened in the ring area (40) with the sealing membrane (28). Torsional vibration damper, in particular dual-mass flywheel (10), for torsional vibration damping between a drive shaft of a motor vehicle engine and a transmission input shaft of a motor vehicle transmission, with a primary mass (12) for introducing a torque, limited relative to the primary mass (12) via an energy storage element (24), in particular an arc spring rotatable secondary mass (14) for transmitting the torque, the primary mass (12) and the secondary mass (14) at least partially delimiting a receiving space (22) for, in particular lubricated, receiving the energy storage element (24), and one between the secondary mass (14) and the primary mass (12) formed friction device (20) according to one of Claims 1 until 8th . Torsional vibration damper Claim 9 , wherein the sealing membrane (28) is fastened with an output flange of the secondary mass (14) protruding from the receiving space (22), with a sealing device on an axial side of the output flange pointing away from the sealing membrane (28) between the output flange and the primary mass (12). (26) is provided for sealing the receiving space (22).

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