DE102008018777A1 - Roller bearing's tilt resistance determining device for wheel bearing unit of motor vehicle, has lever mechanism designed such that it exerts no tilting movement by clamped bearing by its dead weight - Google Patents

Abstract

The device (1) has a clamping device (4) for fixing a bearing unit (10) of a roller bearing (2). A lever mechanism (6) is fastened to another bearing unit (11) for applying tilting movement (M), where the two bearing units are rotatable against each other. The lever mechanism is designed such that it exerts no tilting movement by the clamped bearing by its dead weight. The lever mechanism has a lever (7) that is radial and symmetrical with the clamped bearing. An adapter plate (9) is provided for indirect fastening of the lever to the respective bearing part. An independent claim is also included for a method for determining tilt resistance of a bearing.

Description

Field of the invention

The The invention relates to a device for determining the tilting rigidity a bearing, in particular a rolling bearing. The invention relates further to a method for operating such a device. The device and the method are in particular for the determination the tilting stiffness of wheel bearing units intended for motor vehicles.

Background of the invention

One Bearing generally comprises two about a bearing axis against each other rotatable Bearing parts. In a rolling bearing These bearing parts are usually by an inner ring and an outer ring formed between which rolling elements in Shape of balls, rollers or the like revolve.

One in a wheel bearing unit for a motor vehicle used rolling bearing becomes multifaceted in operation Stressed loads. For example, one practices on a vehicle tire acting lateral force on the rolling bearing a tilting moment, whereby its inner and outer ring against each other by a be tilted at a certain angle.

• 1. Momentensteifigkeit im Lastpunkt (Tangentensteifigkeit): Kippsteifigkeit C_M = Delta Moment dM/Delta Verkippungswinkel dφ
• 2. Linearisierte Momentensteifigkeit (Sekantensteifigkeit): Linearisierte Kippsteifigkeit C_ML = Moment M/Verkippungswinkel φ

Against such tilting the rolling bearing provides a resistance, which is referred to below as the tilting stiffness of the bearing. The tilting stiffness can alternatively be defined as follows:

• 1. Torque rigidity in the load point (tangential stiffness): Tilting stiffness C _M = delta torque dM / delta tilt angle dφ
• 2. Linearized torque stiffness (secant stiffness): Linearized tilt stiffness C _ML = moment M / tilt angle φ

The Tilting rigidity of a rolling bearing is regularly at the production as part of a quality control. traditionally, this determination is made by means of a device in which the roller bearing is acted upon by a force with a defined tilting moment. The resulting tilting of the bearing is often over Axis potentiometer determined.

at a usual one Device for determining the tilting rigidity is a base plate for fixing a bearing part, in particular the inner ring provided. The device further comprises one on the other bearing part fastenable lever, over a force inducing the tilting moment is initiated. Usually This lever is designed as a one-sided lever arm.

Object of the invention

Of the Invention has for its object to provide a device which for a very precise Determination of the tilting rigidity of a bearing, in particular rolling bearing, suitable is. The invention is further based on the object a method particularly suitable for operating such a device specify.

Solution of the task

These Task is relative the device according to the invention solved by the features of claim 1. The device then comprises a Clamping device for fixing a bearing part. The device further comprises a lever means for applying a Tilting moment is fastened to the other bearing part. It is the Lever device designed such that when clamped bearing - in particular in an initial state, in which no additional force on the lever device exercised will - through the weight of the lever device - at least approximately - no tilting moment acts on the bearing.

Regarding the to be carried out by means of the device Method, the object is achieved by the features of the claim 14. Thereafter, a bearing part of the bearing to be tested in the clamping device fixed and the lever device attached to the other bearing part. Over a Force acting on the lever means becomes the bearing for testing purposes subjected to a tilting moment. The force or - equivalently - the overturning moment and a resulting tilting due to this tilting moment of the warehouse are measured. Based on the tilting and the tilting moment finally becomes determines the tilting stiffness of the bearing.

Of the Invention is based on the finding that in conventional testers The camp often already by the mere clamping in the device is already burdened to some extent. In particular, often already by the weight of components of the tester a certain overturning moment exercised on the camp. Erkan Term Ate leads this Effect on measuring errors in the determination of the tilting stiffness.

By the device according to the invention is that for testing purposes applied tilting moment, however, not by a falsifying Self-moment of the lever device superimposed. This will be a special precise Determination of the tilting rigidity achieved.

In In a particularly advantageous embodiment, the inventive compensation of Eigenmomentes the lever device achieved by that as a Part of the lever device provided lever so on the Bearing attachable is that it is radially symmetrical from the bearing projects. The lever is in a particularly simple design Formed a kind of two-armed lever. Also a three or more radial symmetry the lever, in particular a star or disc-shaped lever geometry, are possible. alternative For this purpose, but in principle within the scope of the invention is also conceivable Self-moment of the lever device by means of relief such as springs or Compensate counterweights.

In An advantageous development of the invention is the lever device not only fixable on the bearing without torque, but also beyond that Relieved in the axial direction of force, so that the lever device in the initial state due to their own weight, at least approximately no force exerts on the bearing. The lever device corresponds to this preferably with a relief device. The relief device comprises, in an expedient embodiment, a counterweight, which in terms of force coupled with the lever means that it compensates for their weight.

alternative or additionally the relief device can also by springs or a (in particular Regulated) Hubantrieb be formed. By the axial relief the lever device on the one hand, the measurement accuracy of the device on improved. On the other hand facilitates the relief of the lever device but also the clamping of the bearing, in particular the assembly of the Lever device in stock.

Prefers the clamping device is designed such that the bearing in the Initial state aligned with its bearing axis substantially vertically is. By this arrangement, the camp is also due to its own weight suspended in the clamped state no moment.

Conveniently, the lever device comprises an adapter plate next to a lever for fastening the lever to the associated bearing part, in particular the outer ring of the camp. In a preferred embodiment, the lever device is such designed so that the lever in the initial state with its longitudinal axis substantially perpendicular to the bearing axis - in particular horizontally - aligned is.

Prefers is a lever of the lever device with at least one ball joint provided for the selective introduction of a force. By the force on a Ball joint is on the one hand a punctual, and thus with respect to her Position very exact, force is reached. On the other hand will through the introduction of force over the ball joint achieves that under deflection of the lever the effective Lever arm always remains the same length. This ball joint is preferred displaceable in the radial direction along the lever, so that the effective lever arm arbitrarily selectable is.

Conveniently, Here is a lever of the lever device with two with respect to his Central axis symmetrically arranged ball joints provided. hereby in turn, the lever is symmetrical, in particular with respect to its mass educated. Furthermore This can be advantageous in two opposing force Pages are initiated in the lever.

advantageously, is the device with a laser sensor for determining a Tilting the bearing provided, creating a comparatively accurate Measurement of tilting is realized.

In a preferred embodiment In this case, the lever device comprises a rigid next to a lever with this coupled boom, on which one for the laser pickup detectable sensor point is formed. In particular, the sensor point protrudes into the receiving area of the laser pickup so that the laser pickup detects the position of the sensor point or the cantilever. there is from the position of the sensor point, the tilting of the bearing determinable. In particular, the sensor point is hereby used as a reflector or the like is formed. Optionally, the sensor point is also through the surface the jib itself.

Prefers the laser pickup is designed as a distance sensor, which the Distance to the sensor point determined. From the change of this distance becomes while the tilting of the rolling bearing certainly.

Preferably the device comprises a punch, which for the introduction of force can be advanced against the lever.

For automatic determination of the tilting rigidity, the device expediently comprises an evaluation unit. This evaluation unit is designed to record the force applied to the lever device (or equivalently the tilting moment caused thereby) as well as the tilting of the lever device and to determine therefrom the tilting rigidity of the bearing. In a preferred embodiment, the evaluation unit is simultaneously formed as a control unit for controlling the introduction of force into the lever device. The control and evaluation unit controls in this embodiment au tomatically a drive which the punch for Force is moved against the lever. The evaluation unit or control and evaluation unit is formed in particular by a microcontroller with an evaluation software or control and evaluation software implemented therein.

In advantageous embodiment of the method, several measuring points in the form of a series of measurements recorded. Each measuring point is characterized by a force value and an associated tilt value. The measurement series contains one predetermined number of such measuring points, these measuring points one have successively increasing force value. Instead of the force value can they Measuring points equivalently also contain a moment value. Instead of a tilt value can each measurement point equivalently also a value for the distance to the sensor point, or for that of the sensor point at Contain the tilting of the lever device path covered. A In the sense of the above, such a measurement series will also be referred to as a force-displacement curve designated.

Based the force-displacement curve is determined according to the method, the tilting stiffness. By considering the force-displacement curve, the behavior becomes optional of the bearing shown with increasing load. For example, can possibly an abnormal "kinking" of the curve be determined.

Prefers in this case is the force applied to generate the overturning moment continuously rising steadily - so not jumped into the lever. This will cause unwanted effects, such as for example, by the bearing clearance or a reorientation the rolling elements in the Over the course of the measurement series arise, largely eliminated. Especially For the introduction of force, a punch with a constant feed rate, preferably <10 mm / min, continuously advanced against the lever. By the slow, constant feed is advantageously a quasi-static Load of the warehouse reached.

Conveniently, the recording of the measuring points is triggered by the force value. Thus, the recording of a measuring point is triggered in each case if the force acting on the lever means (or acting on the lever means Moment) reaches a predetermined force setpoint (or torque reference). When recording a series of measurements, a stored list of such force setpoints is displayed (or torque setpoints) processed. Due to the specified force setpoints is a particularly high comparability of different series of measurements scored, since each measurement series measuring points to the same force values having. In this case, in particular, the step size is provided of the measurements to a respective measuring range. For example For force values smaller than 0.5 kN, the measuring points are incremented 0.05 kN, whereas at force values greater than 0.5 kN with a larger increment to be recorded.

Prefers In this case several measurement series with measuring points become identical Force values recorded, with each measurement series measurement pointwise be arithmetically averaged.

In a further preferred embodiment of Method are recorded several series of measurements, the rolling bearing between every two series of measurements by 180 ° in an identical direction of rotation is twisted. In such a rotation of the rolling bearing rolling elements of roller bearing, which run between the inner ring and the outer ring, too, in particular by a maximum of 90 °, postponed. Due to the reorientation of the rolling elements are influences that resulting from the orientation of the rolling elements, at different Measurements changed in each case. In particular, when averaging several, especially four, such Measurements become a comparatively reliable value for the tilting stiffness certainly.

Short description of the drawing

following Be exemplary embodiments of Invention explained in more detail with reference to a drawing. Show:

1 in a partially sectioned illustration a device for determining the tilting rigidity of a roller bearing,

2 a schematic representation of an embodiment of the device with a control and evaluation unit for the automatic determination of the tilting stiffness.

Detailed description of the drawing

each other corresponding parts and sizes are always provided with the same reference numerals in all figures.

1 shows a partially sectioned view of a device 1 for determining the tilting stiffness K ( 2 ) of a rolling bearing 2 a wheel bearing unit 3 , which are here for testing purposes in the device 1 is introduced. The rolling bearing 2 is thus in a test state. In the device 1 becomes the rolling bearing 2 subjected to a tilting moment M. A resulting tilting α of the rolling bearing 2 is determined, and finally on the basis of the tilting moment M and the tilting α, the tilting rigidity K of the rolling bearing 2 determined.

The device 1 includes one in essence chen annular base plate 4 , which on a horizontally oriented - only schematically indicated - bottom plate 5 is rigidly fixed. The base plate 4 serves as a clamping device for the rolling bearing 2 , or the wheel bearing unit 3 , Furthermore, the device comprises 1 a lever device 6 , This lever device 6 comprises a substantially rod-shaped lever 7 , on which on its in the test condition the rolling bearing 2 facing, elongated underside 8th , In the middle approximately a substantially annular adapter plate 9 is appropriate. The adapter plate 9 used to attach the lever device 6 at the rolling bearing 2 ,

The rolling bearing 2 includes as bearing parts an inner ring 10 and an outer ring 11 , between which in two rows several rolling elements 12 to run. The wheel bearing unit 3 in turn comprises an axle piece 13 on which the rolling bearing 2 with its inner ring 10 sitting.

For testing purposes, the axle piece 13 at the base plate 4 bolted so that the roller bearing axis 14 opposite the bottom plate 5 is oriented vertically. The adapter plate 9 will be on the outer ring 11 of the rolling bearing 2 rigidly attached so that the rolling bearing 2 over the lever 7 can be acted upon with the tilting moment M.

To generate the overturning moment M, the lever becomes 7 by a stamp 15 ( 2 ) acted on one side with a vertically downwardly directed force F. This force F is about one on the stamp 15 located force sensor 16 ( 2 ) detected. To force the punch presses 15 on one on the lever 7 attached ball 17 one out of the ball 17 and a corresponding spherical shell 18 formed ball joint 19 , The position of the ball joint 19 is on the lever 7 freely selectable in radial direction. As a result, the force F at any distance R _dyn to the rolling bearing axis 14 in the lever 7 be initiated. The set distance R _dyn is chosen in particular such that it is the wheel tread of a tested wheel bearing unit 3 to be attached wheel corresponds. The wheel rollover describes the distance from the floor to the roller bearing axis when the wheel is mounted on the vehicle. Through the ball joint 19 The force F is selectively in the lever 7 initiated, so that the distance R _dyn , and consequently also the tilting moment M, are particularly precisely adjustable. In particular special in this way the location of the force is independent of the tilted position of the lever 7 ,

The tilting α, ie the angle at which the outer ring 11 opposite the inner ring 10 , or the roller bearing axis 14 due to the attacking overturning moment M is determined by means of a distance measurement. For this purpose, the lever device comprises 6 one on the adapter plate 9 fastened, in test condition substantially parallel to the bottom plate 5 aligned, annular arm 20 at whose bottom plate 5 facing bottom 21 a sensor point P is mounted in the form of a reflector. The sensor point P is in the test state at a distance R to the roller bearing axis 14 in the detection area of one on the bottom plate 5 located laser pickup 22 , With this a vertical displacement of the sensor point P is detected. For this purpose, the laser transducer 22 designed as a distance sensor, which the distance A of the sensor point P to the bottom plate 5 measures. In this case, a distance change and hereby the traveled distance s of the sensor point P are determined from two distance measurements. Taking into account the distance R of the sensor point P to the rolling bearing axis 14 the tilt α is determined on the basis of the path s.

On the basis of the applied tilting moment M and the determined tilting α, finally, the tilting rigidity K of the rolling bearing becomes 2 certainly.

Due to the design of the device 1 is achieved that the rolling bearing 2 in the initial state - when the rolling bearing 2 already on the base plate 4 fixed and the lever device 6 on the outer ring 11 is appropriate, the external force F but not yet created - at least largely free of load.

For this purpose, on the one hand, the lever 7 with respect to its central axis 23 formed symmetrically. In the test state, the lever protrudes 7 thus bilaterally symmetrical radial over the rolling bearing 2 out. As a result, it is at least approximately prevented that already the lever 7 Due to its own weight, a tilting moment M on the rolling bearing 2 exercises. In particular, the entire lever device 6 with respect to the central axis 23 formed symmetrically.

On the other hand, the device includes 1 a relief device 24 , The discharge device 24 comprises a counterweight of the mass M1, that of the mass M2 of the lever device 6 equivalent. The counterweight is via a cable 25 like that with the lever 7 linked, that the weight of the mass M1 just cancel the weight of the mass M2. This ensures that the rolling bearing 2 at least in the initial state no significant axial load by the device 1 is exposed. A radial load of the rolling bearing 2 is due to the vertical arrangement of the roller bearing axis 14 locked out.

In 2 is an embodiment of the device 1 with a control and evaluation unit for the automatic determination of the tilting stiffness K shown schematically.

The control and evaluation unit is here as a PC 26 (Personal Computer), which is an interface card 27 as input and output interface for analog or digital signals. Besides, the PC is 26 provided with a software application SW, which is designed for automatic determination of the tilting stiffness K.

The interface card 27 is on the one hand with a drive 28 to advance the stamp 15 against the lever 7 signal-technically coupled. The software application SW controls the drive via an output signal 28 such that the stamp 15 at a constant feed rate v to the ball joint 19 of the lever 7 moved. This results in a steadily increasing force F on the lever 7 , The Vorschubge speed v is in particular <100 mm / min, causing the bearings 2 is exposed to a quasi-static load. The resulting force F is from the force sensor 16 detected and as an input signal via the interface card 27 the software application SW supplied for evaluation purposes.

Another input signal is via the interface card 27 also the signal of the laser pickup 22 , namely the distance traveled s of the sensor point P, the software application SW supplied. From this, the tilt α is determined.

The software application SW is designed such that upon reaching a certain force setpoint value of the force F, a measuring point is triggered, ie a measuring point in a force-displacement diagram 29 is recorded. The measuring points become within a series of measurements 30 - in which once the force F is increased from 0 kN to 5 kN - recorded at a force F below 0.5 kN with a step size of 0.05 kN, whereas at a force F above 0.5 kN with a larger increment can be recorded. From the resulting force-displacement diagram 29 Finally, by the software application SW - taking into account the distance R _dyn - the tilting stiffness K of the bearing 2 determined and issued.

In order to influence the rolling element alignment in the rolling bearing 2 to exclude as far as possible on the determination of the tilting stiffness K, are several series of measurements 30 recorded, with the lever 7 between every two measurement series 30 - optionally automatically or manually - by 180 ° each in an identical direction of rotation about its central axis 23 is turned. As a result, the rolling elements are oriented 12 inside the rolling bearing 2 by a maximum of 90 °.

At least two, preferably four, such series of measurements 30 are recorded and finally arithmetically averaged by measurement points, to a comparatively reliable determination of the tilting stiffness K of the bearing 2 to get.

1

contraption

2

roller bearing

3

wheel bearing unit

4

baseplate

5

baseplate

6

lever means

7

lever

8th

bottom

9

adapter plate

10

inner ring

11

outer ring

12

rolling elements

13

axle piece

14

Rolling axis

15

stamp

16

force sensor

17

Bullet

18

spherical shell

19

ball joint

20

boom

21

bottom

22

Laser Displacement Transducer

23

central axis

24

relief device

25

cable

26

PC

27

Interface Card

28

drive

29

Force-path diagram

30

measurement series

A

distance

F

force

K

Tilting

M

overturning moment

M1

Dimensions

M2

Dimensions

P

sensor point

R

distance

rdyn

distance

s

path

SW

Software application

v

feed rate

α

tilt

Claims (20)

Contraption ( 1 ) for determining the tilting rigidity (K) of a bearing part which can be rotated relative to one another ( 10 . 11 ) provided warehouse ( 2 ), - with a clamping device ( 4 ) for fixing a bearing part ( 10 ), - and with a lever device ( 6 ), for applying a tilting moment (M) on the other bearing part ( 11 ) is fastened, wherein the lever device ( 6 ) is designed such that with a clamped bearing ( 2 ) exerts on this by its own weight no overturning moment (M). Contraption ( 1 ) according to claim 1, wherein the lever device ( 6 ) one with clamped bearing ( 2 ) radially symmetrically protruding from this lever ( 7 ). Contraption ( 1 ) according to one of claims 1 or 2, wherein the lever device ( 6 ) is relieved to such an extent that, when the bearing is clamped ( 2 ) by their own weight no force on the camp ( 2 ) exercises. Contraption ( 1 ) according to one of claims 1 to 3, wherein the clamping device ( 4 ) is designed such that it the bearing ( 2 ) in clamped state with vertically aligned bearing axis ( 14 ) fixed. Contraption ( 1 ) according to one of claims 1 to 4, wherein the lever device ( 6 ) a lever ( 7 ) and an adapter plate ( 9 ) for indirectly attaching the lever ( 7 ) at the corresponding bearing part ( 11 ) having. Contraption ( 1 ) according to one of claims 1 to 5, wherein the lever device ( 6 ) a lever ( 7 ) which, when the bearing is clamped ( 2 ) substantially perpendicular to the bearing axis ( 14 ) is aligned. Contraption ( 1 ) according to one of claims 1 to 6, wherein the lever device ( 6 ) a lever ( 7 ) and at least one radially eccentric on the lever ( 7 ) resting ball joint ( 19 ) for selectively introducing a force (F). Contraption ( 1 ) according to claim 7, wherein the ball joint ( 19 ) in the radial direction along the lever ( 7 ) is displaceable. Contraption ( 1 ) according to one of claims 1 to 8, lever ( 7 ) Laser sensor ( 22 ) for determining a tilt (α) of the bearing ( 2 ). Contraption ( 1 ) according to claim 9, wherein the lever device ( 6 ) a rigid with a lever ( 7 ) coupled boom ( 20 ), to which one for the laser pickup ( 22 ) detectable sensor point (P) is formed. Contraption ( 1 ) according to claim 9 or 10, wherein the laser sensor ( 22 ) as a distance sensor for determining the distance of a sensor point (P) to the laser pickup ( 22 ) is trained. Contraption ( 1 ) according to one of claims 1 to 11, with a stamp ( 15 ), which for the introduction of force against the lever ( 7 ) is vorschiebbar. Contraption ( 1 ) according to one of claims 1 to 12, having an evaluation unit ( 26 ), which is designed to automatically move one onto the lever device ( 6 ) acting force (F) as well as by this with a clamped bearing ( 2 ) caused tilting (α) of the lever device ( 6 ), and from this the tilting rigidity (K) of the bearing ( 2 ). Method for determining the tilting rigidity (K) of a two against each other about a bearing axis ( 14 ) rotatable bearing parts ( 10 . 11 ) comprehensive warehouse ( 2 ) by means of a device ( 1 ) according to one of claims 1 to 13, - wherein the one bearing part ( 10 ) in the clamping device ( 4 ), - the lever device ( 6 ) on the other bearing part ( 11 ), so that no tilting moment (M) on the bearing ( 2 ), - whereby the lever device ( 6 ) for exercising a tilting moment (M) with respect to the bearing axis ( 14 ) is acted upon eccentrically acting force (F), - whereby a resulting tilting (α) of the bearing parts ( 10 . 11 ) is determined, - and wherein based on the tilting moment (M) and the tilting (α) the Kippsteifigkeit (K) of the bearing ( 2 ) is determined. Method according to Claim 14, in which a plurality of measuring points each having a rising force value and respectively associated tilting value as a measuring series ( 30 ), wherein the tilting stiffness (K) is determined on the basis of this series of measurements ( 30 ) is determined. Method according to one of claims 14 or 15, wherein the force (F) continuously rising steadily in the lever device ( 6 ) is initiated. Method according to one of claims 14 to 16, wherein for force introduction a stamp ( 15 ) with a constant feed rate (v), in particular of about 10 mm / min, continuously against the lever device ( 6 ) is advanced. Method according to one of claims 16 or 17, wherein a measuring point is recorded whenever the detected force (F) has a reached predetermined force setpoint. Method according to one of claims 14 to 18, wherein a plurality of measurement series ( 30 ) are recorded with measuring points at identical force setpoints, whereby in each case those measuring points of the various measurement series ( 30 ) are averaged with corresponding force values. Method according to one of claims 14 to 19, wherein a plurality of measurement series ( 30 ) and the bearing ( 2 ) between every two measurement series ( 30 ) by 180 ° in an identical rotation direction is twisted.