WO2008145456A1

WO2008145456A1 - Shock strut bearing and shock strut

Info

Publication number: WO2008145456A1
Application number: PCT/EP2008/054639
Authority: WO
Inventors: Alexander Zernickel; Gerhard Meyer
Original assignee: Schaeffler Kg
Priority date: 2007-05-25
Filing date: 2008-04-17
Publication date: 2008-12-04
Also published as: DE102007024582A1

Abstract

The invention relates to a shock strut bearing (10) for rotatably supporting a shock strut (30), particularly on a chassis of a motor vehicle, comprising an angular roller bearing (6) having a central axis of rotation (5) and having a number of rollers (11) each engaged relative to the radial direction (7) for rotary support. The rollers (11) of the angular roller bearing (6) are additionally engaged relative to the circumferential direction (12). The invention further relates to a shock strut (30) having such a shock strut bearing (1). A high level of damping of wheel vibrations can be achieved by such a design.

Description

Name of the invention

Suspension strut bearing and strut

description

Field of the invention

The invention relates to a suspension strut bearing for the rotatable support of a strut, in particular on a body of a motor vehicle, wherein for rotary mounting a tapered roller bearing is provided with a central axis of rotation, which comprises a number of employees employed in each case to the radial direction. Furthermore, the invention relates to a shock absorber, in particular for a motor vehicle, with such a suspension strut bearing.

Background of the invention

Such strut bearing is known for example from DE 73 14 041 U. The suspension strut bearing shown there serves for the rotatable support of a

Strut of a motor vehicle relative to the body. By the tapered roller bearing shown there is a steering of the strut arranged

Impeller of the motor vehicle allows. In the suspension strut bearing according to the

DE 73 14 041 U, the tapered roller bearing comprises an inner ring concentric with the axis of rotation and having a running surface for the rollers, wherein the inner ring extends beyond the running surface and is designed as a spring plate. Further, a concentric with the rotation axis outer ring is provided, which is e- benfalls formed as a tread for the rollers. The annular ones

Running surfaces of the outer and inner rings are each conical, resulting in the oblique or employment of arranged between the inner and outer ring rollers to the radial direction. The strut bearing itself is between the mechanical spring, which is located on the spring plate of the inner ring supported, and arranged a rubber buffer, which is mounted opposite a body-mounted part.

With the suspension strut bearing according to DE 73 14 041 U, a compact overall height is achieved with a simultaneously long service life. In particular, this is accomplished by the design of the inner ring as a spring plate.

Object of the invention

The object of the invention is to provide a suspension strut bearing of the type mentioned, which allows improved vibration damping. Further, it is an object of the invention to provide a shock absorber equipped with a strut bearing mentioned above, which has improved vibration damping properties.

Solution of the task

The first object is achieved by a suspension strut bearing with the features of claim 1. Accordingly, a suspension strut bearing for the rotatable support of a strut, in particular on a body of a motor vehicle, is provided, wherein the rotary bearing a tapered roller bearing is inserted with a central axis of rotation, which comprises a number of employed in each case to the radial direction and the circumferential direction rollers.

In a first step, the invention is based on the recognition that in a tapered roller bearing due to the oblique or employment of the rollers to the radial direction during rotation, a slip of the rollers relative to the running surfaces of the bearing occurs. This slippage occurs because the roller ends roll on the running surfaces due to the given inclination on the running surfaces of different lengths.

In a second step, the invention now starts from the consideration that due to this slip for a tapered roller bearing in relation to an axial roller bearing. or compared to an angular contact ball bearing results in increased friction, which can be used to improve the vibration damping of an arranged on the strut impeller.

Finally, in a third step, the invention recognizes that the friction resulting from the slippage of a tapered roller bearing is suitable for setting a desired vibration damping when the rollers of the tapered roller bearing are additionally set to the circumferential direction. In this case, there is no clearly defined rolling line on the running surfaces for the rollers during a rotation of the tapered roller bearing. In other words, runs a role of a tapered roller bearing, which is employed in addition to the circumferential direction, dirty, which further increases the sliding relative to the rolling share. In this case, the sliding component increases with increasing inclination of the rollers in the circumferential direction or with decreasing arrival angle, when the angle of attack is defined as the angle of the longitudinal axis of the roller to the circumferential direction. In the extreme case of an angle of attack of 0 °, the roller moves only sliding over the running surfaces.

The invention offers the advantage that the inclination of the pivot bearing desired for vibration damping can be set via the angle of attack of the rollers of a tapered roller bearing relative to the circumferential direction. This allows ideal vibration damping, as desired, for example, for the respective type of motor vehicle by the vehicle manufacturer. For high vibration damping, the angle of attack is small and for a lower vibration damping the angle of attack is chosen to be large. Through the use of the invention can be further dispensed with known approaches to vibration damping of the suspension strut bearing approaches, such as abrasive seals or abrasive plastic parts. Such solutions also show the known stick-slip problem, which can see by a constant change between sliding and static friction to unwanted vibrations and noise, which is associated with increased wear of the components used. A desired higher friction of the pivot bearing and Thus, a higher vibration damping is achieved solely by the inclination of the rollers of a tapered roller bearing in the circumferential direction.

The use of a tapered roller bearing also has the further advantage that already be absorbed by the bearing as such radial forces.

For a desired vibration damping, in particular in a motor vehicle, the angle between the longitudinal direction of the rollers and the circumferential direction, i. the angle of attack, advantageously between 30 ° and 80 °, preferably between 45 ° and 70 °. Within this range, vibration damping desired by manufacturers depending on the type of vehicle is adjustable via the friction of the tapered roller bearing. In particular, at low angles of attack a large vibration damping is achieved by increased friction of the tapered roller bearing. This is of particular advantage when a motor vehicle places great importance on the fact that wheel vibrations transverse to the direction of travel, which can occur, for example, as a result of unevenness in the terrain, in particular when driving straight ahead, should not be transmitted to the bodywork.

In a further preferred embodiment, adjacent rollers of the tapered roller bearing are set opposite in each case in the circumferential direction. In other words, while rollers in the circumferential direction are alternately inclined once in and once against the circumferential direction. This configuration causes a symmetry of the damping behavior of the tapered roller bearing with respect to the direction of rotation. In particular, an otherwise occurring strong torque change is thereby avoided at a reversal of rotation.

Due to the employment of the rollers in addition to the circumferential direction, it is advisable to guide the rollers in a roller cage. This can be done for example by corresponding oblique recesses in the roller cage To form the tapered roller bearing guided in particular in a roller cage rollers between treads can be arranged, which are formed by other housing parts, for example, for mounting on the body or for receiving the mechanical spring of the shock absorber. In an expedient embodiment, however, the tapered roller bearing comprises an inner ring and an outer ring, each with a running surface, between which the rollers, in particular guided in a roller cage, are arranged. The separate formation of an inner and an outer ring, which form the running surfaces for the rollers, offers the advantage that the choice of material of the other housing parts can be made regardless of the choice of material for the inner and outer ring and thus for the tread. Thus, for example, a housing part, which is designed as a spring plate for receiving the mechanical spring of the shock absorber, and a housing part, which is supported on the body, be made inexpensively from a suitable plastic, whereas the running surfaces and thus the inner and the Outer ring on a roll-resistant metal, such as steel or the like, are formed.

In a further preferred embodiment, the tapered roller bearing is encapsulated. As a result, the tapered roller bearing is protected in particular against contamination or against mechanical effects. The encapsulation can be done for example by a corresponding edge design of the housing parts, between which the tapered roller bearing is arranged.

The second object is achieved by a shock absorber with the combination of features according to claim 7. Accordingly, a strut, in particular for a motor vehicle, is provided which comprises a shock absorber, a mechanical spring and an aforementioned strut bearing, wherein the spring on a housing part of the suspension strut bearing supported, and wherein the shock absorber is arranged coaxially to the central axis of rotation. Such a strut serves on the one hand the shock absorption of an impeller against the body and allows a good vibration damping of wheel vibrations. In particular, on the well-damped tapered roller bearing, at which the rollers are additionally employed in each case for the circumferential direction, vibrations of the impeller transversely to the direction of travel is not or only to a limited extent transmitted to the body.

Short description of the drawing

An embodiment of the invention will be explained in more detail with reference to a drawing. Showing:

1 in an exploded view designed as a tapered roller bearing strut bearing with a housing part and a cap, Fig. 2 is a partial sectional view of the composite strut bearing according to FIG. 2,

3 is an enlarged partial sectional view of the tapered roller bearing of the suspension strut bearing of FIG. 2,

4 shows a roller cage of the tapered roller bearing according to FIG. 3, as well as a partial section of the outer ring with a roller, and FIG. 5 shows schematically a shock absorber of a motor vehicle.

Detailed description of the drawing

In Fig. 1, a suspension strut bearing 1 is shown in an exploded view, as it can be used for the steerable support of an impeller against the body of a motor vehicle. At first, a lower housing part 3 and an upper cap 4 can be seen, between which a tapered roller bearing 6 rotatable about a central axis of rotation 5 is arranged. In this case, the tapered roller bearing 6 comprises a conical inner ring 8 and a conical outer ring 9, between which a conical annular roller cage 10 is also arranged. In a corresponding recesses of the roller cage 10, a number of rollers 11 are rotatably inserted. The inner ring 8 and the outer ring 9 simultaneously form the running surfaces for the rollers 11. Due to the conical configuration of the inner ring 8, the outer ring 9 and the roller cage 11, the rotatable about the central axis of rotation 5 tapered roller bearing 6 is defined. The rollers 11 are thereby employed in each case with respect to the radial direction 7. Upon rotation of the cap 4 relative to the housing part 3, slippage already occurs as a result of the fact that the roller ends of the rollers 11 engaged obliquely to the radial direction 7 roll on the conical running surfaces of the inner ring 8 and the outer ring 9 on a different length of generatrix.

Compared to a regular tapered roller bearing 6, however, the rollers 11 of the illustrated tapered roller bearing 6 are employed in addition to the circumferential direction 12. This can be clearly recognized by the visible inclination of each individual roller 11 in the roller cage 10 along the circumference. In each case, adjacent rollers 11 are oppositely inclined.

The additional oblique or employment of the rollers 11 of the tapered roller bearing 6 to the circumferential direction 12 results in increased friction in a rotation of the housing part 3 relative to the cap 4. This achieves increased damping of vibrations of the impeller against the body. It is true that an even greater friction and thus vibration damping occurs, the smaller the angle of attack relative to the circumferential direction 12, as this increases the sliding relative to the rolling fraction.

The inner ring 8 and the outer ring 9, which each form a running surface for the rollers 11, are made of a rolling-resistant metal. The outer ring 9 lies in a correspondingly conically shaped bearing surface 13 of the housing part 3. The inner ring 8 is supported in a correspondingly conical receiving surface 14 of the cap 4 from. Both the housing part 3 and the cap 4 are made of a plastic. The housing part 3 is provided on its underside with a support surface 17 for receiving or supporting the mechanical spring of a shock absorber. In Fig. 2, the rotatable mounting of the housing part 3 relative to the cap 4 is shown in an enlarged partial sectional view of FIG. 1. It can be seen in this case the cap 4 inserted inner ring 8 and the housing part 3 inserted outer ring 9 of the tapered roller bearing 6. The cut is placed exactly by a roller 11 which is held in a recess of the roller cage 10.

On the housing part 3 is clearly the support surface 17 can be seen, which is designed to support the mechanical spring of a shock absorber.

The cap 4 further comprises a circumferential wall 20 having an inwardly directed bead 21. In addition, the housing part 3, a circumferential, outwardly directed bead 23 is applied. The wall 20 and the bead 21 of the cap 4 and the bead 23 of the housing part 3 are arranged such that in the assembled state, wherein the tapered roller bearing 6 is inserted between the cap 4 and the housing part 3, the wall 20 of the cap 4th with its inwardly directed bead 21, the outwardly directed bead 23 of the housing part 3 overlaps. As a result of this embodiment, encapsulation of the tapered roller bearing 6 is achieved, as a result of which it is protected against contamination and against mechanical influences.

In Fig. 3 is an enlarged partial sectional view of Fig. 2 is shown again, but now only the components of the tapered roller bearing 6 represents. It can be seen here, the conical outer ring 9 and the likewise conical inner ring 8. Between the outer ring 9 and the inner ring 8 of the roller cage 10 is arranged, which carries a number of rollers 11. It can be clearly seen in this illustration, the employment of the rollers 11 at an angle 24 to the radial direction 7, whereby the tapered roller bearing 6 is defined.

4, the roller cage 10 and the outer ring 9 are shown in a perspective view as components of the tapered roller bearing 6. It can be seen clearly that the rollers 11 both to the radial direction 7 and the Circumferentially 12 are employed. It is also apparent that adjacent rollers 11 a and 11 b are each entangled to each other, ie in other words in the circumferential direction 12 have an opposite employment.

In the reduced schematic detail view of FIG. 4 is clearly visible that the rollers 11 due to the conical configuration of the roller cage 10 an angle 24 relative to the radial direction 7 and due to the oblique recesses for the rollers 11 in the roller cage 10 on the tread, here the Outer ring 9, additionally an angle of attack 26 with respect to the circumferential direction 12 have.

In Fig. 5, a strut 30 is schematically drawn for shock absorption of an impeller of a motor vehicle. The shock absorber 30 in this case comprises a coaxial with the axis of rotation 5 arranged shock absorber 32, which acts with its non-visible end on an impeller of the motor vehicle. The central shock absorber 32 has a piston 33 and a piston rod 34, and is protected from dirt by a surrounding collar 35. The sleeve 35 and thus the shock absorber 32 are circulated by a helical mechanical spring 36, which is supported at its upper end against the housing part 3 of a tapered roller bearing 6 according to FIGS. 1 to 3. The housing part 3 in turn is supported on the tapered roller bearing 6 and the cap 4 on a rubber buffer 37. The cap 4 of the tapered roller bearing 6 is mounted on the rubber buffer 37 on a body-mounted fastener 38.

The illustrated strut 30 has a high damping of wheel vibrations relative to the body as a result of designed as a tapered roller bearing 6 with additional circumferentially inclined rollers 11 strut bearing 1. LIST OF REFERENCE NUMBERS

I suspension strut bearing 3 housing part

4 cap

5 axis of rotation

6 tapered roller bearings

7 radial direction 8 inner ring

9 outer ring

10 roll cage

I I roles

12 circumferential direction 13 receiving surface housing part 14 receiving surface cap 17 support surface

20 wall

21 bead 23 bead

24 Angle of attack radial 26 Angle of attack Circumference 30 Strut 32 Shock absorber 33 Piston

34 piston rod

35 cuff

36 spring

37 rubber buffer 38 fastening element

Claims

claims

1. suspension strut bearing (1) for rotatably supporting a strut (30), in particular on a body of a motor vehicle, wherein for rotary mounting a tapered roller bearing (6) is provided with a central axis of rotation (5), which is a number of each to the radial direction (7) set roles (11), characterized in that the rollers

(11) of the tapered roller bearing (6) in addition to the circumferential direction

(12) are employed.

2. suspension strut bearing (1) according to claim 1, characterized in that the angle of attack (26) between the longitudinal direction of the rollers (11) and the

Circumferential direction (12) in each case between 30 ° and 80 °, preferably between 45 ° and 70 °.

3. suspension strut bearing (1) according to claim 1 or 2, characterized in that in the circumferential direction (12) adjacent rollers (11) of the

Tapered roller bearing (6) are set opposite.

4. suspension strut bearing (1) according to one of the preceding claims, characterized in that the rollers (1) are guided in a roller cage (10).

5. suspension strut bearing (1) according to one of the preceding claims, characterized in that the tapered roller bearing (6) comprises an inner (8) and an outer ring (9), each forming a roller track.

6. Suspension strut bearing (1) according to one of the preceding claims, characterized in that the tapered roller bearing (6) is encapsulated.

7. strut (30), in particular for a motor vehicle, with a shock absorber (32), a mechanical spring (36) and with a suspension strut bearing (1) according to any preceding claim, wherein the spring (36) on a housing part (3) the strut bearing (1) is supported, and wherein the shock absorber (32) coaxial with the central axis of rotation (5) is arranged.