DE102010030762A1 - Device for measuring bearing clearance of ball-and-socket joint mounted in landing gears of vehicle, has measurement instrument comprising magnetic field-sensitive sensor secured to releasable magnets outside housing - Google Patents

Abstract

The device (1) has a joint ball (6) comprising ball studs (7) provided with a spigot aperture (3). The joint ball is moveably supported at a free end (17) of the ball studs in an axial direction (29). A measurement instrument is placed in a measuring work area (21) formed on an outer side of the housing. The measurement instrument comprises a magnetic field-sensitive sensor (24) secured to releasable magnets (28) on the outer side of the housing. An evaluating device (33) is connected with the measurement instrument.

Description

The invention relates to a device for measuring the bearing clearance of a ball joint, which is mounted in the chassis of a vehicle and a housing having a pin opening and a ball joint comprising a ball pivot, which is movably mounted with its ball joint in the housing and in an axial direction through the spigot opening extends outwardly from the housing, with a measuring bracket releasably secured to a free end of the ball stud and disposed outside the housing, and a measuring instrument carried by the measuring bracket and disposed outside the housing.

The DE 102 17 612 B4 discloses a measuring device for the bearing clearance on a mounted in the chassis of a vehicle ball joint, which consists of a ball pin whose free end is accessible, as well as at least one ball bearing the ball joint and a bearing shell for this receiving joint housing. A measuring bracket is fixable at the free end of the ball stud and carries a directly or indirectly with an outside portion of the joint housing, which is with respect to the joint ball on the ball stud substantially opposite side of the joint housing cooperating measuring instrument, in direct or indirect action a suitable force on the ball joint or a chassis part connected thereto measures the distance of a relative movement between the ball stud and the joint housing. On the outside portion of the joint housing an auxiliary ball segment can be placed, the ball surface then has substantially the center of the joint ball as the ball center, the measuring instrument interacts directly or indirectly with the spherical surface of the auxiliary ball segment. The auxiliary ball segment is held magnetically or by a detachable adhesive connection on said outer side portion of the joint housing. In particular, the measuring instrument is designed as a dial gauge.

This gauge is non-contact, requiring mechanical contact between the gauge and the ball joint or auxiliary ball segment. With a high measurement accuracy, the measuring instrument is very sensitive, so that a careful handling of the measuring device is required, which takes time. Due to the time pressure prevailing in workshops, there is therefore a need for a more robust solution. Although according to the DE 102 17 612 B4 discloses a non-contact measurement method as an alternative, but it is referred to only flat rate and only the use of optical or electromagnetic waves proposed.

Proceeding from this, the invention has the object, a device of the type mentioned in such a way that a bearing clearance of the ball joint can be determined using a relatively robust measuring instrument with high accuracy.

This object is achieved with a device according to claim 1. Preferred embodiments of the invention are given in the dependent claims.

The inventive device for measuring the bearing clearance of a ball joint, which is mounted in the chassis of a vehicle and a housing having a pin opening and a ball joint comprising a ball pivot, which is movably mounted with its ball joint in the housing and in an axial direction through the pin opening extends out of the housing, has a at a free end of the ball pin releasably secured and arranged outside the housing measuring bracket and a supported by the measuring bracket and arranged outside the housing measuring instrument, the measuring instrument comprises one or at least one magnetic field-sensitive sensor, the the magnetic field of one or at least one outside of the housing is arranged and flooded at this releasably secured magnet is flooded.

By using the magnetic field-sensitive sensor, which interacts with the magnetic field of the magnet, a non-contact measurement of the bearing clearance with high accuracy is possible. Furthermore, the measuring instrument is very robust, since no sensitive mechanical parts protrude from this and must be brought into contact with the ball joint or with an auxiliary body connected thereto. The high accuracy is preferably based on the fact that the magnetic-field-sensitive sensor can detect a change in direction of the magnetic field lines of the magnetic field at the sensor location. The magnetic field-sensitive sensor preferably comprises at least one or more, for example two or three magnetic field-sensitive sensor elements, which preferably have magnetoresistive sensor elements and / or Hall sensor elements or are designed as such sensor elements. A suitable sensor is z. B. from the EP 0 947 846 B1 known.

The magnet is arranged in particular at a distance from the measuring instrument. Preferably, the measuring bracket extends from the free end of the ball stud to the vicinity of the magnet, so that the measuring instrument is opposite to the magnet. Preferably, the magnet is releasably secured to a housing opening opposite the pin opening. The housing bottom may be formed entirely or partially by a housing cover, which in particular closes a housing opening, which preferably lies opposite the journal opening.

According to one embodiment of the invention, the magnet and the measuring instrument are arranged one behind the other in the axial direction. In this case, the magnet is preferably magnetized in the axial direction. This embodiment is particularly suitable for measuring a radial bearing clearance (radial play) of the ball joint. Preferably, a force is introduced to measure the radial clearance in the ball joint in a direction transverse to the axial direction radial direction, so that the housing moves relative to the ball stud in the radial direction, resulting in a detectable by means of the measuring instrument change of the field line profile at the sensor location. Alternatively or additionally, the magnetic induction can be detected at the sensor location by means of the measuring instrument. By measuring the change in the magnetic induction at the sensor location due to a force introduced axially into the ball joint, an axial bearing play (axial play) can also be detected by means of the measuring instrument.

According to an alternative embodiment of the invention, the magnet and the measuring instrument are arranged one behind the other in a radial direction running transversely to the axial direction. Preferably, the magnet is magnetized in the radial direction. The alternative embodiment is particularly suitable for measuring an axial and / or a radial bearing clearance of the ball joint. Preferably, a force is introduced to measure an axial bearing clearance in the ball joint in the axial direction, so that the housing moves relative to the ball pivot in the axial direction, resulting in a detectable by means of the measuring instrument change of the field line profile at the sensor location. Preferably, a force is introduced to measure a radial bearing clearance in the ball joint in a direction transverse to the axial direction other radial direction, so that the housing moves relative to the ball stud in the other radial direction, resulting in a detectable by means of the measuring instrument change of the field line course on Sensor location leads. The radial directions are different in particular. Preferably, the radial directions are perpendicular or substantially perpendicular to each other. Alternatively or additionally, the magnetic induction can be detected at the sensor location by means of the measuring instrument. By measuring the change in the magnetic induction at the sensor location due to a force introduced into the ball joint in the radial direction, a radial bearing play can be detected by means of the measuring instrument. In this case, the radial directions may also coincide. Of course, it is possible in the alternative embodiment to replace the terms "radial direction and" other radial direction "against each other.

By means of the measuring instrument, a change in the magnetic field at the sensor location can be detected. However, such a change in the magnetic field is due to a change in position of the magnet relative to the measuring instrument. If a defined force is introduced into the ball joint, it is thus possible, based on the detected magnetic field change, to conclude the bearing clearance of the ball joint with respect to the defined force.

According to one embodiment of the invention, an evaluation device connected to the measuring instrument is provided, by means of which the change in the magnetic field at the sensor location can be evaluated. In particular, a change in the position of the magnet relative to the measuring instrument can be determined by means of the evaluation device. Preferably, the bearing clearance of the ball joint can be determined by means of the evaluation device.

The magnet is in particular a permanent magnet. This offers the advantage that no electrical supply lines for generating the magnetic field are required. Alternatively, the magnet may also be an electromagnet. The magnet is preferably facing the measuring instrument with a first of its magnetic poles. Furthermore, the magnet with its second magnetic pole is preferably remote from the measuring instrument.

According to one embodiment of the invention, a holder carrying the magnet is provided, by means of which the magnet is releasably secured to the housing, in particular on the housing bottom. The holder and the magnet thus form a magnetic module. Preferably, the holder has an open towards the measuring instrument and in particular made of a ferromagnetic material pot in which the magnet sits. Preferably, the magnet with its second magnetic pole is in contact with the bottom of the pot, so that the second magnetic pole is guided over the bottom of the pot and the edge of the pot in the direction of the measuring instrument. In particular, the pot edge surrounds the magnet. With regard to the magnetic module, the first magnetic pole of the magnet thus forms a first magnetic pole of the magnetic module, wherein the second magnetic pole of the magnet guided by the pot base and the pot rim in the direction of the measuring instrument forms a second magnetic pole of the magnetic module. Thus, the two magnetic poles of the magnetic module facing the measuring instrument, wherein the second magnetic pole of the magnetic module surrounds the first magnetic pole of the magnetic module. The resulting thereby Field course allows a very accurate measurement of the bearing clearance.

The holder is preferably magnetically held on the housing, in particular on the housing bottom, but can alternatively also be clamped by means of a clamping mechanism on the housing or otherwise releasably secured to the housing. The measuring bracket is preferably placed on the free end of the ball stud. In particular, the measuring bracket is bolted to the free end of the ball stud.

According to one embodiment of the invention, the ball pin is fixed, in particular rigidly connected to a first component of the chassis, wherein the housing is fixed, in particular rigidly connected to a second component of the chassis, which is preferably movable relative to the first component. The first component is z. B. by a steering knuckle and the second component is z. B. formed by a link, by a tie rod or by a pendulum support for a stabilizer.

The bearing clearance is measured by means of the device in particular such that in the ball joint, a defined force is introduced, which z. B. attacks in the axial direction or in the radial direction of the ball joint. Furthermore, it is possible that the force has both an axial and a radial component. The introduction of force is preferably carried out by means of a tool, for example via a torque wrench, with a suitable attachment, such. B. a hook wrench is provided. In this case, the force can be introduced into the ball joint via one of the fixedly connected to this chassis components on which the tool can be relatively easily recognized. The introduction of force into the ball joint must therefore not be immediate, which is advantageous because the ball joint is already mounted in the chassis. The introduction of force leads to a change in position of the housing relative to the ball stud and thus also to a change in position of the measuring instrument relative to the magnet. This change in position can be detected by means of the measuring instrument and can be quantified by means of the evaluation device connected to it. Since the introduced force is known, can be determined based on the determined change in position, the bearing clearance of the ball joint with respect to the introduced force.

The magnetic field-sensitive sensor can detect the course of the magnetic field, in particular the course of the field lines of the magnetic field preferably in a plurality, preferably in two or three spatial directions. According to one embodiment of the invention, the magnetic-field-sensitive sensor for each spatial direction comprises one or at least one magnetic field-sensitive sensor element.

The evaluation device preferably comprises a comparison unit, by means of which the detected change in the magnetic field or a value derived therefrom can be compared with one or more reference values. Thus, it is possible by means of the evaluation device to make a judgment as to whether the bearing clearance is below a predetermined limit or within predetermined limits. If this is the case, the ball joint is ready for use. If this is not the case, the ball joint is broken and should, for. B. be replaced. The assessment of whether the ball joint is ready for use or defective, is preferably made by means of the evaluation. The evaluation device preferably comprises a microcontroller or a window module, by means of which the comparison unit can be implemented.

• – Der ein Magnetfeld erzeugende Magnet wird an das Gelenkgehäuse angebracht.
• – Der Sensor wird mittels eines am Kugelzapfen fixierten Messbügels gehalten.
• – Der Sensor misst die Änderung des Magnetfelds bei Bewegungen des Gehäuses relativ zum Kugelzapfen.
• – Ein Mikrokontroller oder ein „Fenster-Modul” bestimmt auf Basis der Größe der Magnetfeldänderung, ob das Kugelgelenk in Ordnung oder nicht in Ordnung ist.
• – Der Magnet zur Maßverkörperung wird vorzugsweise an einem Verschluss- oder Gehäusedeckel des Kugelgelenks über einen Haftmagneten fixiert. Alternativ zum Haftmagneten kann auch ein Klemmmechanismus verwendet werden. Weiterhin alternativ kann der Magnet auch an anderer Stelle am Gehäuse angebracht werden.
• – Je nach Ausrichtung des Magnetmoduls wird z. B. entweder das Radialspiel oder das Axial- oder Radialspiel gemessen.

The measurement of the bearing clearance is carried out, for example, as follows:

• - The magnetic field generating magnet is attached to the joint housing.
• - The sensor is held by means of a measuring pin fixed to the ball stud.
• - The sensor measures the change in the magnetic field during movements of the housing relative to the ball stud.
• A microcontroller or "window module" determines whether the ball joint is in order or not based on the magnitude of the magnetic field change.
• - The magnet for dimensional standard is preferably fixed to a closure or housing cover of the ball joint via an adhesive magnet. As an alternative to the holding magnet, a clamping mechanism can also be used. Furthermore, alternatively, the magnet can also be mounted elsewhere on the housing.
• - Depending on the orientation of the magnetic module z. B. either the radial clearance or the axial or radial clearance measured.

• – Messung des freien Spiels (unzulässig hohe Gelenkelastizität) des Kugelgelenks.
• – Die Messung kann im Fahrzeug im eingebauten Zustand des Gelenks erfolgen (keine Demontage erforderlich).
• – Es lässt sich sowohl das Radialspiel als auch das Axialspiel messen.

The device according to the invention has the following advantages in particular:

• - Measurement of free play (inadmissibly high joint elasticity) of the ball joint.
• - The measurement can be carried out in the vehicle when the joint is installed (no disassembly required).
• - It can measure both the radial play and the axial play.

The invention will be described below with reference to preferred embodiments with reference to the drawing. In the drawing show:

1 a partial sectional view of a device according to a first embodiment of the invention and

2 a partial sectional view of a device according to a second embodiment of the invention.

1 shows a partially sectioned view of a device 1 according to a first embodiment of the invention. A ball joint 2 includes a with a pin opening 3 provided housing 4 in whose interior 5 a joint ball 6 comprehensive ball stud 7 with his joint ball 6 is rotatably and pivotally mounted, extending in an axial direction 29 through the pin opening 3 through the case 4 extends out. The joint ball 6 sits slidably in a bearing shell 8th in the interior 5 arranged and on the housing 4 is fixed. On his the tenon opening 3 opposite side is the case 4 with a through a housing cover 9 closed mounting hole 10 provided, wherein the housing cover 9 at the same time forms the housing bottom. Further, a pin opening 3 sealing bellows 11 provided on the housing 4 is attached and up to one outside the case 4 arranged pin area 12 of the ball stud 7 extends. The pin area 12 includes a conical section 13 stuck in a through hole 14 a steering knuckle 15 sitting. The hole 14 includes a conical area 16 at which the conical area 13 of the ball stud 7 is applied. The ball stud 7 extends through the hole 14 through and has at its the housing 4 opposite free end 17 an external thread 18 on which a mother 19 is screwed on. The mother 19 is supported, possibly with the interposition of a washer, on one of the housing 4 opposite side of the steering knuckle 15 thus securing the ball stud 7 on the steering knuckle 15 , With the housing 4 is a handlebar 20 rigidly connected, which is indicated only schematically. The steering knuckle 15 and the handlebars 20 are thus on the ball joint 2 hinged together. Furthermore, the vehicle coordinate system is drawn, wherein x denotes the vehicle longitudinal direction, y the vehicle transverse direction and z the vehicle vertical direction.

The free end 17 of the ball stud 7 extends through the mother 19 passing, taking on the free end 17 a measuring bracket 21 is attached, on the one hand to the steering knuckle 15 supported and on the other hand by means of a thread 18 the free end 17 screwed nut 22 at the free end 17 is fixed. The measuring bracket 21 extends from the free end 17 close to the housing cover 9 and points to its free end 17 opposite end region 23 a magnetic field sensitive sensor 24 comprehensive meter. Between the housing cover 9 and the sensor 24 is a holder 25 arranged by means of a magnet 26 magnetically on the housing cover 9 is held. On her the sensor 24 facing side forms the holder 25 a pot 27 in which a permanent magnet 28 sitting. The magnet 28 is in the axial direction 29 of the ball joint 2 magnetized, taking the the sensor 24 opposite pole S of the magnet 28 in contact with the bottom of the pot 30 stands. The pot 27 , preferably the entire holder 25 , is made of ferromagnetic material, so that on the bottom of the pot 30 adjacent pole S of the magnet 28 over in the axial direction 29 extending pot edge 31 towards the sensor 24 is guided. The one towards the sensor 24 guided pole thus surrounds the sensor 24 facing pole N of the magnet 28 , Some field lines of the magnet 28 generated magnetic field are shown schematically and by the reference numeral 32 characterized. Furthermore, an evaluation device 33 shown schematically with the sensor 24 electrically connected. According to 1 forms the at the bottom of the pot 30 adjacent pole S of the magnet 28 the south pole and the sensor 2 facing pole N of the magnet 28 the North Pole. But it is also a reverse magnetization of the magnet 28 possible.

Is in a direction transverse to the axial direction 29 extending radial direction 35 a force Fr in the housing 4 initiated, so the housing moves 4 relative to the ball stud 7 along the radial direction 35 running arrow 34 , This changes the magnetic field at the location of the sensor 24 , what by means of the evaluation 33 is detectable. The extent of this magnetic field change is a measure of the radial clearance of the ball joint 2 at attacking force Fr. By means of the evaluation device 33 can now be determined whether the radial clearance is within or outside predetermined limits. The radial direction 35 runs here in the vehicle transverse direction y.

In the first embodiment, the magnet 28 and the sensor 23 in the axial direction 29 arranged one behind the other, the magnet 28 in the axial direction 29 is magnetized. The first embodiment is thus particularly suitable for measuring the radial clearance of the ball joint 2 ,

2 shows a partially sectioned view of a device 1 according to a second embodiment of the invention, wherein to the first embodiment, similar or identical features with the same reference numerals as in the first embodiment are designated. According to the second embodiment, the holder 25 and the measuring bracket 21 formed such that the magnet 28 and the sensor 24 in a direction transverse to the axial direction radial direction 36 are arranged one behind the other, wherein the permanent magnet 28 in the radial direction 36 is magnetized. Further extends the pot edge 31 in the radial direction 36 , The radial direction 36 runs here in the vehicle longitudinal direction x and thus transverse to the radial direction 35 according to 1 ,

Is in the axial direction 29 a force Fa in the ball studs 7 introduced, so the ball pin shifts 7 relative to the housing 4 in the axial direction 29 , This shift leads to a change in the magnetic field at the location of the sensor 24 and is thus by means of the evaluation device 33 detectable. Alternatively, in the radial direction 35 a force Fr in the housing 4 be initiated, whereupon the housing 4 relative to the ball stud 7 in the direction of the arrow 34 moved (see 1 ). This movement causes a change in the magnetic field at the location of the sensor 24 , which by means of the evaluation device 33 is detectable. The second embodiment is thus suitable both for the detection of an axial bearing clearance and a radial bearing clearance. Apart from these differences, the second embodiment is constructed analogously to the first embodiment, so that reference is made to the description of the first embodiment for further description of the second embodiment.

LIST OF REFERENCE NUMBERS

1

Device for measuring the bearing clearance

2

ball joint

3

pin opening

4

Housing of the ball joint

5

Interior of the housing

6

joint ball

7

ball pin

8th

bearing shell

9

housing cover

10

mounting hole

11

bellows

12

Spigot area of the ball stud

13

conical section of the pin area

14

through hole in steering knuckle

15

journal

16

conical area of the hole

17

free end of the ball stud

18

external thread

19

mother

20

handlebars

21

measuring bracket

22

mother

23

End area of the measuring bracket

24

Magnetic field sensitive sensor

25

bracket

26

Holding magnet

27

Pot of the holder

28

permanent magnet

29

axial direction of the ball joint

30

Bottom of the pot

31

Edge of the pot

32

Field lines of the magnetic field

33

evaluation

34

movement direction

35

radial direction

36

radial direction

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

• DE 10217612 B4 [0002, 0003]
• EP 0947846 B1 [0007]

Claims (13)

Device for measuring the bearing clearance of a ball joint ( 2 ), which is mounted in the chassis of a vehicle and a housing ( 4 ) with a pin opening ( 3 ) and a joint ball ( 6 ) comprising ball studs ( 7 ), which with its ball joint ( 6 ) movable in the housing ( 4 ) and in an axial direction ( 29 ) through the pin opening ( 3 ) through the housing ( 4 ), with one at a free end ( 17 ) of the ball stud ( 7 ) detachably fastened and outside the housing ( 4 ) arranged measuring bracket ( 21 ), one of the measuring bracket ( 21 ) and outside the housing ( 4 ) arranged measuring instrument, characterized in that the measuring instrument at least one magnetic field-sensitive sensor ( 24 ) of the magnetic field of at least one outside of the housing ( 4 ) arranged and releasably attached to this magnet ( 28 ) is flooded. Device according to claim 1, characterized in that the magnet ( 28 ) detachably on one of the pin opening ( 3 ) opposite housing bottom ( 9 ), the measuring bracket ( 21 ) from the free end ( 17 ) of the ball stud ( 7 ) to the vicinity of the magnet ( 28 ) so that the measuring instrument is attached to the magnet ( 28 ) is opposite. Device according to claim 1 or 2, characterized in that the magnet ( 28 ) and the measuring instrument in the axial direction ( 29 ) are arranged one behind the other. Device according to claim 3, characterized in that the magnet ( 28 ) in the axial direction ( 29 ) is magnetized. Device according to claim 1 or 2, characterized in that the magnet ( 28 ) and the measuring instrument in a direction transverse to the axial direction ( 29 ) extending radial direction ( 36 ) are arranged one behind the other. Device according to claim 5, characterized in that the magnet ( 28 ) in the radial direction ( 36 ) is magnetized. Device according to one of the preceding claims, characterized by an evaluation device connected to the measuring instrument ( 33 ), by means of which a change in the position of the magnet ( 28 ) is determinable relative to the measuring instrument. Device according to one of the preceding claims, characterized by a magnet ( 28 ) supporting bracket ( 25 ), by means of which the magnet ( 28 ) detachable on the housing ( 4 ) is attached. Apparatus according to claim 8, characterized in that the holder ( 25 ) a pot open to the measuring instrument and consisting of ferromagnetic material ( 27 ), in which the magnet ( 28 ) sits. Apparatus according to claim 8 or 9, characterized in that the holder ( 25 ) magnetically on the housing ( 4 ) is held. Device according to one of the preceding claims, characterized in that the measuring bracket ( 21 ) with the free end ( 17 ) of the ball stud ( 7 ) is screwed. Device according to one of the preceding claims, characterized in that the ball pivot ( 7 ) is fixedly connected to a first component of the chassis, the housing ( 4 ) is fixedly connected to a second component of the chassis, which is movable relative to the first component. Apparatus according to claim 12, characterized in that the first component by a steering knuckle ( 15 ) and the second component by a handlebar ( 20 ) is formed.

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