DE20022909U1 - torsional vibration damper - Google Patents

Description

Liermann Castell P01227

Torsional vibration damper

The invention relates to a torsional vibration damper. Torsional vibration dampers are used to dampen torsional vibrations, in particular in drive trains, and generally consist of at least one primary mass and one secondary mass, which are mounted so that they can rotate relative to one another. In addition, such torsional vibration dampers generally have damping devices, such as friction elements or fluid damping, which counteract a relative rotational movement of the primary mass and secondary mass to one another. Depending on the specific design, spring elements or similar can also be provided in order to influence the damping characteristics in a suitable manner or to reset the relative rotational position of the primary mass and secondary mass in the event of a zero load.

In particular, the invention relates to torsional vibration dampers that can be used in a drive train of a motor vehicle. In such torsional vibration dampers, one of the two masses, usually the primary mass, is connected to the drive of the motor vehicle or to an internal combustion engine. The other of the two

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The driving forces are transmitted via the secondary masses, usually via the secondary mass. In particular, the invention relates to torsional vibration dampers in which a clutch, for example a friction clutch, is provided on the output side. In this case, the output mass, such as the secondary mass, can be a component of the friction clutch.

It is an object of the present invention to provide a torsional vibration damper which is relatively simple in construction and yet can be operated reliably over a very long period of time.

As a solution, the invention proposes a torsional vibration damper according to the independent claims.

In particular, the invention proposes a torsional vibration damper consisting of at least one primary mass and one secondary mass, which are mounted so that they can rotate relative to one another via at least one plain bearing. Such a plain bearing is structurally relatively simple and can be mounted relatively easily during the manufacture of the torsional vibration damper.

Preferably, at least one dry-lubricated plain bearing is provided so that during the service life of the torsional vibration damper an unpredictable consumption of

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Lubricanthi cannot occur. In this way, the reliability of the torsional vibration damper can be increased considerably. In addition, the use of a dry-lubricated plain bearing means that a lubrication step can be omitted during the manufacture of the torsional vibration damper.

Such a plain bearing can be provided particularly easily if it comprises at least one assembly made of plastic. Such an assembly made of plastic can thus be provided without any problems using the injection molding process. On the one hand, it is possible to directly inject such an assembly onto either the primary mass or the secondary mass. On the other hand, such an assembly can also be provided as a separate component and positioned accordingly on the primary mass or the secondary mass in a positioning work step.

Self-lubricating plastics such as Teflon or similar are particularly suitable.

The properties of the plain bearing are particularly consistent when it includes at least one assembly made of injection-molded solid plastic. With such an arrangement, there is no need to worry about the different phases of this assembly becoming separated during the service life of the torsional vibration damper.

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Depending on the requirements for the strength of the plastic assembly used for the plain bearing, this can also have a metal-plastic composite, which allows the stability of this assembly to be adapted in a suitable manner. In addition, such an assembly is characterized by its extremely high thermal stability.

The plain bearing preferably comprises at least one L-profile-shaped flanged bushing. Such a flanged bushing is able to ensure both a radial bearing and an axial bearing effective in an axial direction. Such an arrangement thus makes it possible to provide two of the three necessary bearing components with a single assembly.

For example, a bearing disk extending in the radial direction can be used to absorb the axial forces acting in the other axial direction. On the other hand, the plain bearing can also have two L-profile-shaped flanged bushings, in which the radially directed legs of the L-profile-shaped flanged bushings each serve to support the bearing in one of the two axial directions.

Instead of using two L-profile-shaped flanged bushings, a bearing bush with two flanges can also be used, whereby these two flanges preferably serve to absorb the axial forces.

Such L-profile-shaped flange bushings can be manufactured directly by injection molding, for example. In this way, the flange is directly

Uermann-Castell P01227

Depending on the choice of plastic used, especially when using a metal-plastic composite, the collar can also be formed using a subsequent deformation process. In this case, it is advantageous during production if such a collar is formed before the corresponding collar bushing is fixed to the primary mass or the secondary mass.

If a bearing bush with two collars is used in the torsional vibration damper, an assembly to be used as a bearing bush with a corresponding previously formed collar can be provided with a projection that is dimensioned such that a second collar can be formed from the projection if the assembly is positioned accordingly on the primary mass or the secondary mass. Such a second collar can be provided, for example, by a forming process.

When manufacturing the torsional vibration damper, it is important to note that an assembly to be used as a plain bearing must first be positioned on the primary mass or on the secondary mass before the primary mass and the secondary mass are connected to one another in a rotationally movable manner. Depending on the specific application, it may be advantageous for this assembly to be fixed to either the primary mass or the secondary mass after it has been positioned accordingly. Fixing in this way ensures that the assembly serving as a plain bearing is firmly connected to either the primary mass or the

Liermann Castell P01227

Secondary mass and thus, corresponding to the rotational movement between primary mass and secondary mass, is in rotational contact with the other of these two masses. Accordingly, with such an arrangement, the running surface of the plain bearing is precisely defined.

Such a fixing can be ensured, for example, by pressing the assembly serving as a plain bearing either with the primary mass or with the secondary mass.

In order to be able to more easily counteract thermal stress on the plain bearing, at least one bearing body of the plain bearing can have at least one slot. Such a slot can, for example, be axially directed and point in the radial direction. Such a slot is therefore suitable for radially directed areas of the bearing body that run in the circumferential direction, such as a collar described above. Such a slot can also easily be used to carry out a forming process that may be used during the manufacture of the torsional vibration damper. A radially directed slot pointing in the axial direction can also be provided. Such a slot can be provided in bush-like areas of the bearing body, i.e. in areas of the bearing body that extend axially around the main axis of the torsional vibration damper. Such a slot enables thermal expansion of the bearing body in the circumferential direction, so that the bearing diameter does not change or only changes insignificantly due to thermal influences.

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Such slots can also completely cut through the corresponding bearing body, so that it is formed from two separate assemblies. In the present context, the term "directed" refers to the direction in which the contactor cuts through the respective bearing body in the direction of the thickness of the bearing body, while the term "direction" refers to the direction along which the slot runs on the surface of the bearing body.

In addition, at least one bearing body of the plain bearing can have a slot pointing in the circumferential direction, which is directed axially or radially depending on the shape of the bearing body - in the radial extension direction or axial extension direction.

In order to ensure that the plain bearing according to the invention is provided with sufficient precision even if the primary mass, the secondary mass or at least one of the components of the plain bearing is manufactured relatively imprecisely or with relatively large tolerances, it is advantageous if at least one running surface of the plain bearing is calibrated. Such post-treatment serves to precisely define the running diameter of at least one component of the plain bearing, whereby this defined running diameter is preferably adapted to an existing running diameter of another component. The component adapted in this way can be provided, for example, on the secondary mass or on the primary mass. Likewise, a

Liermann Castell P01227

Plastic assembly or a dry-lubricating assembly of the plain bearing must be defined accordingly in its running diameter.

The post-treatment of the running surface can be carried out, for example, using a mandrel, which calibrates the entire running surface in the desired manner in one step. In addition, calibration can also be carried out by means of post-treatment, in particular by means of machining, for example by turning.

The calibration process can take place before or after fixing or flanging the plain bearing. If the calibration process takes place before flanging or fixing, a very precisely dimensioned mandrel or protection can be provided for the calibrated component after calibration, so that this component is less affected by the subsequent flanging process or the subsequent fixing process. In particular, this can minimize spring effects that can occur during flanging. On the other hand, calibration is more precise if it is carried out after the other processing processes, especially after fixing or flanging. If there are very high demands on accuracy, calibration can also take place both before and after.

The plain bearing can be designed to be constant over a very long service life at a relatively low load if it is arranged as far radially outward as possible, at least radially outside of fastening means with which the primary mass is connected to a drive.

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Such an arrangement surprisingly makes it possible to use relatively inexpensive materials for the plain bearing, so that the costs for the plain bearing remain within reasonable limits despite the overall higher material expenditure due to the relatively large circumferential surfaces.

The idling properties of the torsional vibration damper according to the invention can, on the other hand, be improved if the plain bearing is located radially inside the fastening means via which the primary mass is connected to a drive. With such an arrangement, the total area of the surfaces sliding on one another is very small, so that the corresponding surface friction is also low. This is particularly important in idling processes, such as those that occur when the clutch is disengaged, since with such arrangements relatively small forces act on the bearing and existing surface friction significantly influences the properties of the torsional vibration damper.

It is particularly advantageous if the plain bearing has two partial bearings, of which a first partial bearing is arranged radially inside the fastening means and a second partial bearing is arranged radially outside the fastening means. With such an arrangement, competing problems can be specifically optimized for the respective partial bearings. In this way, a bearing can be provided that is relatively easy to assemble thanks to the separate components, whereby the scope for reducing manufacturing costs increases in an unexpected way.

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For example, it is possible to produce both partial bearings from a single disc-shaped blank, as they have different diameters. In other words, the inner remainder that accrues for the radially outer assembly during a punching process or similar can be used to produce the radially inner assembly. The reduction in material thus enables cost savings.

Preferably, the radially inner part bearing has a radial bearing. Due to the essentially rotationally symmetrical arrangement of the torsional vibration damper, such a radial bearing is subject to only relatively low radially directed forces, so that the relatively high surface pressure at this point is not significant. However, this arrangement enables a relatively low overall friction due to the small sliding surfaces, so that the idle properties of the torsional vibration damper are advantageously influenced.

Preferably, the second partial bearing, which is arranged radially outside the fastening means, comprises an axial bearing for absorbing forces that accelerate the primary mass and the secondary mass axially apart. Such forces occur to a greater extent in torsional vibration dampers used in conjunction with clutches only in the disengaged state. In such a state, however, a high surface friction is of only minor importance, since

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When the clutch is open, the drive train is severed. When the clutch is closed, this axial bearing is unloaded, so that its relatively high surface friction, which is, however, very low overall due to the unloading, has only a negligible disadvantage. Due to the overall low load, this bearing can be selected relatively inexpensively with the same service life.

In addition, in order to ensure that the primary mass and the secondary mass are securely supported, a torsional vibration damper must also have an axial bearing to absorb the forces that accelerate the primary mass and the secondary mass axially towards each other. Depending on the specific force balance, it may be advantageous to arrange this axial bearing radially inside the fastening means or radially outside the fastening means.

The separation of the plain bearing into at least two partial bearings, which are arranged radially outside or radially inside the fastening means, furthermore makes it possible to build the torsional vibration damper according to the invention relatively narrow in the axial direction, since the partial bearings can be arranged radially overlapping.

It is understood that in the present context the primary mass or the secondary mass can also consist of several components. In addition, the present invention is not limited to torsional vibration dampers that explicitly use flywheel masses for torsional vibration damping. Rather, the invention can be applied to

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All torsional vibration dampers are used in which two components are mounted so that they can rotate relative to each other and interact with each other in order to dampen torsional vibrations.

Further properties, advantages and objectives of the present invention are explained in the following description of the attached drawing, in which three torsional vibration dampers are shown as examples. In the drawing:

Figure 1 shows a first torsional vibration damper in section,

Figure 2a a second torsional vibration damper in section

Figure 2b shows a calibration mandrel in section and

Figure 3 shows a third torsional vibration damper in section.

The torsional vibration dampers shown in the figures each comprise a primary mass 1 and a secondary mass 2, which are connected to one another in a rotationally movable manner via a plain bearing 3. The primary mass 1 can be connected to a drive, such as a motor vehicle internal combustion engine, via a screw 9 (only shown in Figure 3), which passes through the primary mass 1 through a bore 11 (only numbered in Figures 1 and 2a). Each of the primary masses 1 is provided with a starter ring gear 12, which can be operatively connected to the starter of a motor vehicle. In the embodiments shown, the primary mass 1 and the

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Secondary mass 2 are operatively connected to one another via a thrust piston-spring arrangement 13, which counteracts a relative rotational movement of the two masses 1, 2 against one another both in a resilient and frictional manner. The space with the thrust piston-spring arrangement 13 is sealed to the outside by a sealing arrangement 14.

As shown schematically in Figure 3, the secondary mass 2 can be connected to a housing 15 of a clutch, by means of which a friction flow to a friction disk 16 can be selectively established or interrupted.

The embodiments shown in Figures 1 and 2a have a primary mass 1 which comprises two subassemblies Γ and 1", which form a substantially U-shaped bearing shell for the secondary mass 2.

In the embodiment shown in Figure 1, two bearing bushes 4 and 5 are arranged in the bearing shell, which have a substantially L-shaped cross-section. In this respect, this plain bearing has a radially directed slot pointing in the circumferential direction, in which the bearing bushes 4 and 5 can expand thermally. In this embodiment shown in Figure 1, the bearing bushes 4 and 5 are first injection-molded from plastic and then pressed onto the secondary mass 2. The running surfaces of the bearing bushes 4 and 5 are then machined so that they can be placed between the assemblies Γ and 1" of the primary mass 1 with a suitable tolerance.

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The embodiment according to Figure 2a has a one-piece bearing bush 6. This comprises two collars 7 and 8, which ensure axial guidance. Longitudinal slots, i.e. axially directed slots pointing in the radial direction, are provided in the collars 7 and 8. The bearing bush 6 consists of a metal-plastic composite and is initially manufactured as an L-shaped assembly with only the collar 7 during assembly. In addition, an overhang is provided in this process stage, which is dimensioned such that it can be folded over to form the second collar 8. The bearing bush 6 prepared in this way is inserted into the central bore of the secondary mass 2 and suitably positioned in this way. The bearing bush 6 is fixed to the secondary mass 2 by folding the overhang to form the collar 8. The slots make it easier to bend over and prevent material damage. In this exemplary embodiment, the radial inner side of the bearing bush 6 is then machined to match the radially outward-facing bearing surface of the assembly 1. It is also possible to carry out this machining step on the radially outward-facing bearing surface of the assembly 1".

In another manufacturing process for the embodiment according to Figure 2a, a mandrel 20 shown in Figure 2b is used for calibration. This is pushed through the bearing bush 6 in the direction of the arrow. In this process, a shoulder area 23, which has a spherical shell-shaped portion, initially passes through the bearing bush 6. The shoulder area 23 ensures good guidance of the mandrel 20. If

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If the mandrel 20 is guided further into the cylinder bushing 6, a calibration area 22 is created which has a calibration diameter and expands the cylinder bushing 6 to the nominal diameter. The length of the calibration area 22 is less than 10%, preferably less than 8% or less than 5%, of the calibration or nominal diameter. With a nominal diameter of 100 mm, the length of the calibration area 22 can be 2 mm, for example. A holding area 21 is connected to the calibration area 22.

In the embodiment shown in Figure 3, both the primary mass 1 and the secondary mass 2 each consist of two assemblies Γ, 1" and 2', 2". In addition, the plain bearing 3 is formed by two partial bearings 4 and 10. In this embodiment, different material thicknesses are used - as explained below. However, it is also conceivable to manufacture these partial bearings 4, 10 from a single blank.

The partial bearing 4 is located radially within the fastening screws 9 and is essentially L-shaped. During assembly, it is pressed into the knee of the assembly 1". The partial bearing 10, which counteracts forces that move the primary masses 1 and the secondary mass 2 axially away from each other, is sprayed onto the assembly 1" and is fixed to it in this way. For assembly, the assembly 1" is first placed on the assembly 2". Following this, the resulting position of the running surfaces of the

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Subassembly 2' is determined in relation to the bearing bush 4. Following this, in a machining step, these running surfaces are reworked by turning in such a way that when the subassemblies 2' and 2" are assembled, the subassembly 1" is mounted with the necessary tolerance. As is immediately apparent, this embodiment is relatively narrow, since parts of the bearing 3, namely the radial bearing through the bush of the partial bearing 4 and the axially effective partial bearing 10, are arranged axially at the same height.

Claims (26)

1. Torsional vibration damper, consisting of at least one primary mass ( 1 ) and one secondary mass ( 2 ) which are mounted so as to be rotatable relative to one another, characterized in that the primary mass ( 1 ) and the secondary mass ( 2 ) are mounted so as to be rotatable relative to one another via at least one plain bearing ( 3 ). 2. Torsional vibration damper according to claim 1, characterized in that at least one dry-lubricated plain bearing ( 3 ) is provided. 3. Torsional vibration damper according to claim 1 or 2, characterized in that the plain bearing ( 3 ) comprises an assembly made of plastic. 4. Torsional vibration damper according to claim 3, characterized in that the plain bearing ( 3 ) comprises an assembly made of injection-molded solid plastic. 5. Torsional vibration damper according to claim 3 or 4, characterized in that the plain bearing ( 3 ) comprises an assembly which has a metal-plastic composite. 6. Torsional vibration damper according to claim 5, characterized in that the metal-plastic composite has a plastic layer and the plastic layer is at least 0.1 mm thick. 7. Torsional vibration damper according to one of claims 1 to 6, characterized in that the plain bearing ( 3 ) comprises at least one L-profile-shaped flange bushing ( 4 , 5 ). 8. Torsional vibration damper according to claim 7, characterized in that the plain bearing ( 3 ) comprises two L-profile-shaped flange bushings. 9. Torsional vibration damper according to one of claims 1 to 8, characterized in that the plain bearing ( 3 ) has at least one bearing bush ( 6 ) with two collars ( 7 , 8 ), which preferably serve to absorb axial forces. 10. Torsional vibration damper according to one of claims 1 to 9, characterized in that the plain bearing ( 3 ) has at least one bearing body with at least one axially directed slot pointing in the radial direction. 11. Torsional vibration damper according to one of claims 1 to 10, characterized in that the plain bearing ( 3 ) has at least one bearing body with at least one radially directed slot pointing in the axial direction. 12. Torsional vibration damper according to one of claims 1 to 11, characterized in that the plain bearing ( 3 ) has at least one bearing body with at least one radially directed slot pointing in the circumferential direction. 13. Torsional vibration damper according to one of claims 1 to 12, characterized in that the plain bearing ( 3 ) has at least one bearing body with at least one axially directed slot pointing in the circumferential direction. 14. Torsional vibration damper according to one of claims 1 to 13, characterized in that the plain bearing ( 3 ) is fixed to the primary mass ( 1 ) or to the secondary mass ( 2 ) by pressing. 15. Torsional vibration damper according to one of claims 1 to 14, characterized in that the plain bearing ( 3 ) has at least one running surface which is post-treated via a mandrel for calibration. 16. Torsional vibration damper according to one of claims 1 to 15, characterized in that the plain bearing ( 3 ) has at least one running surface which is post-treated for calibration by machining, for example by turning. 17. Torsional vibration damper according to one of claims 1 to 16, wherein the primary mass ( 1 ) is connected to a drive via fastening means ( 9 ), characterized in that the plain bearing ( 3 ) is arranged radially outside the fastening means ( 9 ). 18. Torsional vibration damper according to one of claims 1 to 16, wherein the primary mass ( 1 ) is connected to a drive via fastening means ( 9 ), characterized in that the plain bearing ( 3 ) is arranged radially inside the fastening means ( 9 ). 19. Torsional vibration damper according to one of claims 1 to 16, wherein the primary mass ( 1 ) is connected to a drive via fastening means ( 9 ), characterized in that the plain bearing ( 3 ) has two partial bearings ( 4 , 10 ), of which a first partial bearing ( 4 ) is arranged radially inside the fastening means ( 9 ) and a second partial bearing ( 10 ) is arranged radially outside the fastening means ( 9 ). 20. Torsional vibration damper according to claim 19, characterized in that the first partial bearing ( 4 ) comprises a radial bearing. 21. Torsional vibration damper according to claim 19 or 20, characterized in that the first partial bearing ( 4 ) comprises an axial bearing, preferably for absorbing forces accelerating the primary mass ( 1 ) and the secondary mass ( 2 ) axially towards one another. 22. Torsional vibration damper according to one of claims 19 to 21, characterized in that the second partial bearing ( 10 ) comprises an axial bearing, preferably for absorbing forces which accelerate the primary mass ( 1 ) and the secondary mass ( 2 ) axially apart. 23. Torsional vibration damper according to claim 19 or 20, characterized in that the second partial bearing comprises two axial bearings, one for absorbing forces accelerating the primary mass ( 1 ) and the secondary mass ( 2 ) axially towards each other and a second for absorbing forces accelerating the primary mass ( 1 ) and the secondary mass ( 2 ) axially apart. 24. Mandrel ( 20 ) for calibrating a cylinder bush ( 6 ), in particular for use in a method for producing a torsional vibration damper according to one of the preceding claims, characterized in that the mandrel ( 20 ) has a calibration region ( 22 ) with a calibration diameter and a projection region ( 23 ) arranged upstream in the calibration direction, the diameter of which is smaller than the calibration diameter. 25. Mandrel according to claim 24, characterized in that the attachment region ( 23 ) comprises a spherical shell-shaped portion. 26. Mandrel according to claim 36 or 37, characterized in that the length of the calibration area is less than 10% of the calibration diameter.