DE102011083097A1 - Wheel bearing i.e. shockproof ball bearing, for motor car, has flange and outer ring forming stopper unit with stop surfaces, and damping element provided between stop surfaces and coupling stop surfaces with one another during stop attack - Google Patents

Abstract

The bearing (2) has a bearing element (5) rotatably mounted in an outer ring (4). A flange (28) is connected with the bearing element and partially projects above the outer ring in a radial manner. The flange and the outer ring form an axial stopper unit with stop surfaces in a projection region. A damping element (34) is provided between the stop surfaces and couples the stop surfaces with one another during stop attack. The bearing element is formed as an inner ring, and roller bodies (10) are arranged between the inner ring and the outer ring.

Description

Field of the invention

The invention relates to a wheel bearing according to the preamble of claim 1. The wheel bearing should be particularly suitable for a motor vehicle.

Background of the invention

Wheel bearings are used for axial and / or radial fixation of a wheel to a stationary component such as a steering knuckle. They absorb radial and / or axial forces between the wheel and the steering knuckle and at the same time enable the rotation of the wheel. Furthermore, the wheel bearing fastening elements, such as a flange, via which the wheel or the steering knuckle is fixable on the wheel bearing.

In automotive engineering wheel bearings are usually designed as rolling bearings, as for example in the WO 2009 008 152 A1 is disclosed. The wheel bearing has an inner ring and a relative to the inner ring rotatable outer ring. An inner ring flange is connected to the inner ring, while an outer ring flange is connected to the outer ring. If the wheel is attached to the inner ring flange and the knuckle to the outer ring flange, the wheel bearing rotatably supports the wheel via the inner ring and the outer ring on the steering knuckle. Between the inner ring flange and the outer ring, an axial gap is formed.

Object of the invention

It is an object of the invention to provide an improved wheel bearing, in particular with regard to an axial impact absorption.

Solution of the task

The object is solved by the features of the independent claims. Preferred embodiments of the invention are the subject of the dependent claims.

The invention is based on the idea to provide a damping element in the axial gap between the at least partially overhanging and thus forming an axial stop abutment surfaces of the inner ring flange and the outer ring.

The consideration is based on the consideration of intentionally minimizing the axial gap in a known wheel bearing between the flange of a bearing element such as the inner ring and the outer ring in the overhang area to increase the life of the wheel bearing. This consideration is based on the idea that in the case of an axial impact, such as a curb bump, physical contact should be forced between the flange and the outer ring. In this way, derived during the axial impact of the flange on the rolling elements and raceways in the outer ring and then in the stub axle of the vehicle axial forces can now be derived directly through the outer ring, without rolling elements and raceways are claimed. Without the reduced axial gap, the rolling elements would press in the axial impact in the raceways and leave so-called Brinellierungen, which can cause an increase in the running noise and on the other an unnecessary premature failure of the entire wheel bearing.

Due to the smallest possible design of the axial gap between the flange and the outer ring, however, it can come at high lateral forces on the vehicle, which may arise, for example, a fast cornering with high axial acceleration, even when driving to contact between the outer ring and flange. This contact would cause a noticeable noise and could in addition lead to functional impairment of the wheel bearing.

In order to ensure the curve load capacity of the wheel bearing despite the smallest possible designed axial gap, the invention proposes to provide a damping element between the at least partially overhanging and so in the axial gap to each other forming an axial stop stop surfaces of the inner ring flange and the outer ring. A damping element is essentially characterized in that it is provided for receiving a kinetic energy of a body and for converting the absorbed kinetic energy into another form of energy. In this way, the kinetic energy is removed from the body, so that it is slowed down. The damping element thus brakes the relative movement between the outer ring and the inner ring flange in the axial gap, so that the contact partners impact less strongly. As a result, noise and bearing damage when cornering can be reduced, or even avoided, if the axial gap is designed to reduce the impact of a Borston impactor to a minimum.

The invention therefore provides a wheel bearing which comprises an outer ring, a bearing element rotatably mounted in the outer ring and a flange connected to the bearing element and at least partially radially projecting over the outer ring, wherein the flange and the outer ring form an axial stop with respective stop surfaces in the overhang area. The specified Wheel bearing comprises a damping element between the stop surfaces, via which the stop surfaces couple together in the attack attack.

The damping element between Innenringflansch and outer ring in the specified wheel bearing avoids not only potentially unpleasant noise when cornering, the lower impact energy between Innenringflansch and outer ring and the material of the specified wheel bearing is protected in a contact of Innenringflansches and the outer ring and so the specified wheel better before a protected from premature material fatigue.

The mounted in the outer ring bearing element depends on the type of bearing. Thus, in a sliding bearing, the bearing element directly be the axis or a shaft, at the axial ends, for example, the flange of the specified wheel bearing connects. However, the bearing element is particularly preferably an inner ring of a roller bearing, wherein between the inner ring and the outer ring, which form a corresponding radial gap, rolling elements are arranged.

In one embodiment of the invention, the damping element is attached to the gap reduction on a stop surface. In this way, axial shocks of the outer ring are effectively damped against the flange.

In an additional development, the damping element is annular and arranged on an axial, directed to the flange end face of the outer ring. In this way, the damping element can absorb the forces resulting from an impact between the inner ring flange and outer ring surface and distribute optimally on its surface facing the inner ring flange. Alternatively, the damping element can also be arranged on a surface opposite the end surface on the inner ring flange.

In an alternative or additional development, the specified wheel bearing comprises a housing in the damping element with a gas received therein, which is compressible by a piston which can be moved into the housing via the stop surfaces. A gas as a damping medium to absorb the impact forces is particularly favorable because it not only compress over a long way it is also often compressible without showing fatigue.

In a preferred embodiment, the wheel bearing comprises a sealed by the piston shaft in the housing, wherein the piston is movably mounted in the shaft. By the piston, the housing can on the one hand be hermetically sealed to prevent the gas from escaping, on the other hand, the piston can be used as part of the damping element to take on one of the abutment surfaces, the impact forces between the inner ring flange and the outer ring.

In a further preferred embodiment, the specified wheel bearing comprises a chamber connected to the shaft with the gas which is compressible in the chamber from the piston. By the chamber connected to the shaft, the gas is disposed away from the housing opening and thus better prevents escape of this.

In an additionally preferred development, the specified wheel bearing comprises a liquid arranged between the shaft and the chamber for transmitting a pressure resulting from the movement of the piston into the chamber. The liquid additionally establishes a material barrier between the gas and the housing opening in the shaft, which further impedes the escape of the gas.

In a particularly preferred development, the specified wheel bearing comprises a perforated area between the chamber and the shaft. The perforation increases the flow resistance of the liquid between the chamber and the shaft and thus further increases the damping effect.

In an alternative or additional embodiment, the specified wheel bearing comprises a snap seal which can be closed by the piston on the shaft. Due to the snap seal not only when closing the housing opening by the piston, an overpressure in the shaft are constructed, escaped from the housing gas is so constantly refilled, so that the damping element can be used as often as desired under ideal conditions.

In a particular embodiment of the invention, one of the abutment surfaces has its opposite surface on the damping element a reduced coefficient of friction, so that between the inner ring flange or the outer ring and the damping element a sliding bearing is created. This can be accomplished by treating at least a portion of the surfaces in the axial gap between the inner ring flange and the outer ring. For this purpose, all manufacturing measures can be used that go beyond a pure production of Innenringflansches and the outer ring and lead after pure production to a further reduction of the coefficient of friction between the inner ring flange or the outer ring and the damping element in an eventual stop. Exemplary and non-limiting manufacturing measures for Reibbeiwertreduktion be explained below. Due to the friction coefficient reduction, the respective contact surfaces are protected against abrasion and associated bearing damage.

Alternatively, the reduced coefficient of friction can also be realized by the damping element itself, wherein, for example, the above-mentioned shaft and the above-mentioned piston with a low coefficient of friction against each other are arranged rotatable. The low friction coefficient can be realized, for example, solely by the above-mentioned liquid absorbed in the shaft or the gas in the shaft.

In a further development of the invention, the bearing element and the outer ring on mutual bearing contact surfaces with modified properties on which the outer ring is rotatably mounted on the bearing element. Such modifications can be achieved by hardening, grinding or coating. The bearing contact surfaces and the stop surfaces are the same. In this way, the sliding bearing can be realized in the specified wheel bearing with the same manufacturing steps and the same tools as the wheel bearing realizing bearing contact elements between the outer ring and the bearing element. This not only saves manufacturing costs, it can also be a high throughput in the production can be achieved, since no tool change between the production of the bearing contact elements and the plain bearing is necessary.

In a preferred embodiment, the bearing contact surfaces are formed as a raceway. The raceway is a surface portion in a bearing contact surface of the bearing element or the outer ring, which is designed for circumferentially guiding the respective other bearing partner in the wheel bearing.

In a particularly preferred development, the bearing contact surfaces extend into the abutment surfaces. In this way, the bearing contact surfaces and the stop surfaces can be realized with a single manufacturing step, so that the throughput in the production of the specified wheel bearing can be further increased.

In one embodiment of the invention, the stop surfaces are hardened. Curing can be achieved by any means that compacts the surface structure, such as a mechanical surface treatment or a heat treatment. By curing an elastic and / or plastic deformation of the stop surfaces of the inner ring flange and / or the outer ring can be avoided in the event of contact, whereby a high resistance of the sliding bearing between the inner ring flange and the outer ring is achieved.

In an alternative or additional embodiment of the invention, the abutment surfaces are ground. By grinding the contact surfaces of the sliding bearing can be made flat in the specified wheel bearing, resulting in a high reduction of the friction coefficient. As a material for contact surfaces are general rolling bearing steels, such as 100Cr6.

In a further additional or alternative embodiment of the invention, the stop surfaces are coated. Due to the coating, the material used for the sliding bearing can be used independently of the remaining material of the wheel bearing and designed, for example, for high resistance and / or for a low coefficient of friction.

In a further development, the stop surfaces are coated with a wear-resistant material. Wear resistance is the resistance of a solid to mechanical abrasion. The coating can for example be done permanently with ceramic materials that are particularly resistant to wear. Alternatively, a short-term coating during operation of the bearing can be done for example by a suitable lubrication.

In an alternative or additional development, the material used for the coating has a good emergency running property, in particular of greater than 30 s. A runflat property is understood to mean the time that a bearing without lubrication remains functional. The emergency running property makes it possible to use the slide bearing in particular in a vehicle without further lubrication over the entire life of the wheel bearing, since it can be assumed that the lateral forces mentioned above, for example, by the high axial acceleration on the vehicle at a fast cornering and thus the Contact between inner ring flange and outer ring occurs between the stop surfaces only for very short periods.

Short description of the drawing

Embodiments of the invention are explained below with reference to a drawing. Showing:

1 in a sectional representation of a wheel bearing,

2 : in a section according to 1 a first embodiment variant,

3 : in a section according to 1 a second embodiment

4 : in a section according to 1 a third embodiment

5 : in a section according to 1 a fourth embodiment and

6 : in a section according to 1 a fifth embodiment.

Detailed description of the drawing

In the following figures, the same elements are given the same reference numerals and described only once.

It will open 1 Reference is made, which is a sectional view of a wheel bearing 2 shows. The wheel bearing 2 has an outer ring 4 , a bearing element 5 from a first inner ring 6 and a second inner ring 8th and between the outer ring 4 and the bearing element 5 arranged rolling elements 10 on, each in a rolling element cage 12 being held.

The first inner ring 6 has a first inner ring raceway 14 on, in which a first set of rolling elements 10 rolling inserted. About the first inner ring 6 is the outer ring 4 with a first outer ring raceway 16 pushed on the first set of rolling elements 10 is up. The first inner ring raceway 14 and the first outer raceway 16 together form a guide for the first set of rolling elements 10 ,

The outer ring 4 also has a second outer raceway 18 in which a second set of rolling elements 10 is laid. In the first inner ring 6 is the second inner ring 8th with a second inner ring raceway 20 in a not closer referenced recess in the first inner ring 6 inserted in such a way that the second set of rolling elements 10 through the second inner raceway 20 against the second outer ring raceway 18 is lifted. The second outer raceway 18 and the second inner raceway 20 together form the guide for the second set of rolling elements 10 ,

The outer ring 4 and the inner rings 6 . 8th together define a radial gap 22 , To protect the rolling elements 10 and the raceways 14 to 20 for example, from abrasion and overheating is in the radial gap 20 filled a lubricant, not shown, its escape by means not described in detail seals 24 is avoided. Also prevent the seals 24 Ingress of dirt from outside.

In the first inner ring 6 is a wheel hub, not shown, receiving a positive fit. For this purpose, has a recess in the middle of the first inner ring 6 Form-fitting elements 26 on.

From the first inner ring 6 extends radially outward a flange 28 , From the inner ring flange 28 extends axially a wheel bolt 30 for attachment of a wheel, not shown. It also penetrates the inner ring flange 28 axially an inner ring thread 32 for provisional brake disc fixing during assembly before they are finally fixed by wheel bolts or nuts.

Between the wheel bolt 30 opposite axial side of the inner ring flange 28 and the axial end face of the outer ring 4 is a damping element 34 . 38 trained, which is not shown here.

A first embodiment of the damping element 34 will be described below on the basis of 2 and 3 described. Thereafter, the damping element 34 one in a housing 37 movable piston ring 38 exhibit. The housing 37 is in an annular shaft 40 in which the piston ring 38 axially movable, and two to the annular shaft 40 adjacent annular chambers 42 divided. In the annular shaft 40 is a liquid 44 picked up by the piston ring 38 into the annular chambers 42 can be pressed. These are the annular chambers 42 to the annular shaft 40 over a perforated area 46 open.

Is in the in the 2 and 3 shown damping element 34 a pressure on the piston ring 38 for example, by a taper of the axial gap between the inner ring flange 28 and the outer ring 4 applied, so presses the piston ring 38 the liquid 44 through the perforated area 46 in the chambers 42 , This compresses the fluid 44 Gas in the chambers 42 that by the liquid 44 in the chambers 42 is included. By this compression process, the movement of the piston ring 38 and thereby also the taper of the axial gap between the inner ring flange 28 and outer ring 4 attenuated.

In this state, the piston ring 38 in the liquid 44 in the shaft 40 swim and rotate in the circumferential direction. During this rotation in the floating state, the damping element acts 34 at the same time as a plain bearing between the inner ring flange 28 and the outer ring 4 , Alternative or additional options a sliding bearing between the inner ring flange 28 and the outer ring 4 to be provided are described below.

In 4 is an alternative or additional second embodiment of the damping element 34 shown.

After that, the shaft points 40 at the piston housing opening a barb ring 48 on. The shape of the piston ring 38 is at this point to the shape of the barb ring 48 customized. Am in the shaft 40 sufficient end of the piston ring 38 is the piston ring 38 radially reinforced, allowing it to pull out of the shaft 40 against the barb ring 48 pushes and the shaft 40 closes.

Will the piston ring 38 in 3 against the barb ring 48 pressed and the shaft 40 of the damping element 34 closed, so creates the radially reinforced portion of the piston ring 38 together with the barb ring 48 an overpressure inside the shaft. This pressure must be the piston ring 38 when re-inserted into the shaft 40 counteract what leads to the intended damping effect.

The surface on the inner ring flange 28 can be radial next to the damping element 34 to the radial gap 22 directed a survey 49 have, so that the inner ring flange 28 the outer ring 4 in case of contact.

One too 2 alternative embodiment, the damping element 34 in the wheel bearing 2 is training in 5 shown.

After that is a the damping element 34 opposite surface on the inner ring flange 28 with a material 50 coated.

The material 50 should be designed wear-resistant. In this way, with a rubbing contact of the surface on the inner ring flange 28 with the damping element 34 the abrasion of the contact partners are kept low. Consequently, damage to the inner ring flange 28 and the damping element 34 be reduced or completely avoided when the outer ring 4 axially against the inner ring flange 28 during a rotation of the inner ring flange 28 in the outer ring 4 or vice versa. In particular, ceramic materials offer sufficient wear and abrasion resistance. Alternatively, alloys of cobalt, tungsten, nickel and / or molybdenum may be used.

In addition, a material 50 be selected with good Notlaufeigenschaft, the rubbing contact in the sliding bearing between the inner ring flange 28 and damping element 34 without lubrication for at least 30 s. Especially when using the wheel bearing 2 in a vehicle this is sufficient, as an axial stop of the inner ring flange 28 to the damping element 34 comparatively rare and can only be expected over short periods of time. Materials whose emergency running properties meet these requirements are, for example, bronze, gunmetal, graphite or molybdenum disulfide.

Another too 2 alternative or additional, the damping element 34 in the wheel bearing 2 is training in 6 shown.

After that is the axial contact area 44 on the inner ring flange 28 opposite the damping element 34 ground and / or hardened.

The axial contact region is preferred 44 Hardened and ground in the same way as bearing contact areas 54 , between the rolling elements 10 and the first inner ring raceway 14 or at the first outer ring raceway 16 ,

Particularly preferably, these bearing contact areas extend 54 to the axial contact area 52 into it, causing the bearing contact areas 54 and the axial contact area 52 can be produced in one step.

LIST OF REFERENCE NUMBERS

2

Wheel bearings

4

outer ring

6

inner ring

8th

inner ring

10

rolling elements

12

Cage

14

career

16

career

18

career

20

career

22

gap

24

cassette seal

26

Form-fitting element

28

flange

30

bolt

32

Rifle

34

damping element

36

neckline

37

casing

38

annular piston

40

shaft

42

chamber

44

liquid

46

perforation

48

barb

50

coating

52

contact area

54

contact area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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

• WO 2009008152 A1 [0003]

Claims (10)

Wheel bearing ( 2 ) comprising an outer ring ( 4 ), one in the outer ring ( 4 ) rotatably mounted bearing element ( 5 ) and one with the bearing element ( 5 ) and at least partially radially the outer ring ( 4 ) overhanging flange ( 28 ), the flange ( 28 ) and the outer ring ( 4 ) in the Überkragungsbereich each other form an axial stop with respective abutment surfaces, characterized by a damping element ( 34 ) between the stop surfaces over which the stop surfaces couple together in the attack attack. Wheel bearing ( 2 ) according to claim 1, wherein the bearing element ( 5 ) is an inner ring, and between inner ring and outer ring ( 4 ) Rolling elements ( 10 ) are arranged. Wheel bearing ( 2 ) according to claim 1 or 2, wherein the damping element ( 34 ) is attached to the gap reduction on a stop surface. Wheel bearing ( 2 ) according to one of the preceding claims, wherein the damping element ( 34 ) is annular and at an axial, to the flange ( 28 ) directed end face of the outer ring ( 4 ) is arranged. Wheel bearing ( 2 ) according to one of the preceding claims, comprising a housing ( 37 ) in the damping element ( 34 ) with a gas received therein, through a via the stop surfaces in the housing ( 37 ) movable piston ( 38 ) is compressible. Wheel bearing ( 2 ) according to claim 5, comprising one through the piston ( 38 ) closed shaft ( 40 ) in the housing ( 37 ), the piston ( 38 ) in the shaft ( 40 ) is movably mounted. Wheel bearing ( 2 ) according to claim 6, comprising one with the shaft ( 40 ) connected chamber ( 42 ) with the gas in the chamber ( 42 ) from the piston ( 38 ) is compressible. Wheel bearing ( 2 ) according to claim 7, comprising between the shaft ( 40 ) and the chamber ( 42 ) arranged liquid ( 44 ) for transmitting one by the movement of the piston ( 38 ) resulting pressure in the chamber ( 42 ). Wheel bearing ( 2 ) according to claim 8, comprising a perforated area ( 46 ) between the chamber ( 42 ) and the shaft ( 40 ). Wheel bearing ( 2 ) according to any one of claims 6 to 9, comprising one through the piston ( 38 ) lockable snap seal ( 48 ) at the shaft ( 40 ).

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