Ball and socket joint for a vehicle

Abstract

A ball joint for a vehicle, with a ball pin that has a joint ball, a joint housing that encloses the joint ball and is provided with a pin opening, in which the joint ball of the ball pin is fitted and able to move. The ball pin extends out of the joint housing through the pin opening. An actuator can press a pressure element, in an axial direction, against the joint housing in such a manner that pressure can be exerted by the joint housing and the pressure element onto the joint ball. The actuator acts upon a spring which acts upon the pressure element. The length of the spring can be measured by a displacement sensor.

Claims

1. A ball joint, for a vehicle, with a ball pin (3) comprising: a joint ball (2), a joint housing (9) enclosing the joint ball (2) and being provided with a pin opening (10) in which the joint ball (2), of the ball pin (3), is fitted and movable, the joint housing defines an axis, the ball pin (3) extending out of the joint housing (9) through the pin opening (10), an actuator (14) having a static part and a moving part, the static part is axially fixed with respect to the joint housing and the moving part is connected to the static part, the moving part is axially movable with respect to the static part such that movement of the moving part away from the static part presses a pressure element (11) in an axial direction (7) against the joint housing (9) such that pressure is exerted by the joint housing (9) and the pressure element (11) onto the joint ball (2), the actuator comprising a spring (12) that extends axially and by way of which the actuator (14) acts upon the pressure element (11), and a displacement sensor (19) comprising a sensor element and an emitter element for measuring an axial length (d) of the spring (12), a first axial end of the spring and one of the sensor and the emitter elements abut a common surface of the moving part of the actuator, and a second axial end of the spring and the other of the sensor and the emitter elements abut a common surface of the pressure element.

2. The ball joint according to claim 1, wherein the ball joint comprises an evaluation unit (20) which is connected to the sensor element of the displacement sensor (19), by which a force (F), exerted by the pressure element (11) on the joint ball (2), is determinable.

3. The ball joint according to claim 1, wherein the emitter element (17) and the sensor element (18) are aligned with each other along the axis, at least one signal emitted by the emitter element (17), is detectable by the sensor element and the signal provides information about an axial distance between the moving part of the actuator and the pressure element as well as the length (d) of the spring (12).

4. The ball joint according to claim 3, wherein the emitter element is connected to the second end of the spring (12) that is coupled to the pressure element (11) and the sensor element is connected to the first end of the spring (12) that is coupled to the actuator (14) so that a distance, between the sensor element and the emitter element (17, 18), depends upon the axial length (d) of the spring (12).

5. The ball joint according to claim 3, wherein the emitter element (17) comprises a permanent magnet and the sensor element (18) comprises a sensor that is sensitive to a magnetic field, and a magnetic field from the permanent magnet is arranged to pass through the sensor.

6. The ball joint according to claim 1, wherein the spring (12) is selected from a group of springs consisting of a spiral spring, a cup spring, a leaf spring and a membrane spring.

7. The ball joint according to claim 1, wherein the moving part of the actuator (14) is axially movable relative to the static part of the actuator and is coupled to the pressure element (11) and the spring (12) is interposed therebetween.

8. The ball joint according to claim 1, wherein the ball joint comprises a ball socket (4) that is arranged in the joint housing (9) and surrounds the joint ball (2), the joint ball (2) is fitted and movable in the ball socket, and the ball socket (4) is arranged in the axial direction (7) between the pressure element (11) and an abutment (22) of the joint housing.

9. The ball joint according to claim 8, wherein the ball socket (4) comprises two ball socket components (5, 6), a first of the ball socket components (5) is axially in contact with another surface of the pressure element (11) opposite the common surface thereof and a second of the ball socket components is axially in contact with the abutment (22), and the joint ball (2) is arranged, in the axial direction (7), between the first and the second ball socket components (5, 6).

10. The ball joint according to claim 8, wherein the ball socket (4) is made integrally and is compressible in the axial direction (7) by the actuator (14).

11. A ball joint for a vehicle, the ball joint comprising: a ball pin comprising a joint ball; a joint housing enclosing the joint ball such that the joint ball being movably fitted within the joint housing, and the joint housing comprises a pin opening through which the ball pin extends in an axial direction out of the joint housing; an actuator comprises a static part and a moving part, one axially facing surface of the static part abuts an axial end of the joint housing such that the static part of the actuator is axially fixed relative to the joint housing, the moving part abuts an opposite axially facing surface of the static part, a control unit is connected the actuator and axially moves the moving part relative to the static part an axial surface of the moving part that is axially opposite the static part contacts one axial end of a spring, an opposite axial end of the spring abuts, in the axial direction, against a pressure element and the pressure element contacts the joint ball, the moving part being axially movable to axially bias the spring and the pressure element to apply pressure on the joint ball; and a displacement sensor being fixed to the axial surface of the moving par that is axially opposite the static part, and the displacement sensor measures a separation distance between the moving part of the actuator and the pressure element and thereby a length of the spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, the invention is described with reference to preferred example embodiments illustrated in the drawing, which shows:

(2) FIG. 1: A schematic longitudinal section through a first embodiment of a ball joint;

(3) FIG. 2: A schematic longitudinal section through a second embodiment of a ball joint.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIG. 1 shows a schematic longitudinal section through a first embodiment of a ball joint 1, wherein a ball pin 3 is fitted with its joint ball 2 able to rotate and/or swivel within a ball socket 4. The ball socket 4 comprises a first ball socket component 5 and a second ball socket component 6, the ball socket components 5 and 6 being in contact on different sides in an axial direction 7 with the joint ball 2. Furthermore, the second ball socket component 6 has a pin opening 8 through which the ball pin 3 extends axially out of the ball socket 4. In this first embodiment the ball socket 4 is made in two parts so that the ball socket components 5 and 6 are separate components. The ball socket 4 is arranged together with the joint ball 2 in a joint housing 9, which is also provided with a pin opening 10 through which the ball pin 3 extends out of the housing 9. The ball pin 3 has a pin portion 21 connected solidly to the joint ball 2.

(5) The first ball socket component 5 can be displaced in the axial direction 7 within the housing 9, whereas in contrast the second ball socket component 6 rests in the axial direction 7 against an abutment 22 of the housing 9. On a side of the first ball socket component 5 facing away from the joint ball 2 is attached a pressure element 11 which, with interposition of a spring 12, is coupled to a moving part 13 of an actuator 14. A static part 15 of the actuator 14 is fixed to the housing 9. The actuator 14 is connected to a control unit 16 by which it can be controlled. In particular the moving part 13 of the actuator 14 can be moved by means of the control unit 16 in the axial direction 7 relative to the static part 15, in such manner that the distance d between the moving part 13 and the pressure element 11 can be varied. A change of the distance d, however, also results in a change of the force F exerted in the axial direction 7 by the actuator 14 with the spring 12 interposed upon the pressure element 11. The pressure element 11 passes on the force F to the first ball socket component 5, which therefore presses the joint ball 2 in the axial direction 7 against the second ball socket component 6. Since the actual distance d corresponds to the actual length of the spring 12 and this is arranged in the force flow between the actuator 14 and the ball socket component 5, from the length d and the spring constant of the spring 12, the force F can be calculated using Hooke's law. For this, in particular the spring constant is assumed to be known.

(6) On a side of the pressure element 11 facing toward the moving part 13 an emitter element 17 is fixed, which is opposite a sensor element 18 attached to a side of the moving part 13 facing toward the pressure element 11 and which is an axial distance away from the emitter element 17. For example the emitter element 17 is a permanent magnet and the sensor element 18 is in the form of a sensor sensitive to magnetic fields, through which the magnetic field of the permanent magnet passes. A change of the distance between the pressure element 11 and the moving part 13 thus results in a change of the magnetic field at the location of the sensor, which can be detected by the sensor. The emitter element 17 and the sensor element 18 together therefore form a displacement sensor 19 by means of which the distance d can be determined.

(7) The sensor element 18 is connected to an evaluation unit 20 and provides this information about the distance d, so that by means of the evaluation unit 20, the force F exerted by the spring 12 on the pressure element 11 can be calculated. For this purpose the spring constant of the spring 12 is stored as a datum. Furthermore, preferably the length of the unloaded spring 12 is also stored in the evaluation unit 20 as a datum. In the embodiment shown, the evaluation unit 20 is composed of zfthe control unit 16.

(8) At its end remote from the pin opening 10, the housing 9 is closed by a cover 23 which is held in place by an appropriately shaped housing rim 24.

(9) FIG. 2 shows a schematic longitudinal section through a second embodiment of a ball joint 1. In the figure, features similar or identical to those in the first embodiment are indexed the same way as in the first embodiment. Otherwise than in the first embodiment, the ball socket 4 is made in one piece and is arranged in the axial direction 7 between the pressure element 11 and the housing abutment 22. Thus, the ball socket 4 is in contact with both the pressure element 11 and the abutment 22. If now the moving part 13 of the actuator 14 is displaced in the axial direction 7 relative to the static part 15, in such manner that the axial distance d between the moving part 13 and the pressure element 11 changes, which results in a change of the force F exerted in the axial direction 7 by the actuator 14 with the spring 12 interposed upon the production element 11, the pressure element 11 transmits the force F to the ball socket 4 which is thereby compressed axially so that the pressure exerted on the joint ball 2 increases.

(10) The pressure element 11 is provided with a conical recess into which the ball socket 4 fits with a first conical outer surface. Moreover, the abutment 22 is also provided with a conical recess into which the ball socket 4 fits with a second conical outer surface axially opposite the first conical outer surface. The housing 9 too is made in two parts, with a first housing part 25 and a second housing part 26 that is screwed into the first housing part 25 by means of a thread 27.

(11) Apart from that difference the second embodiment is substantially the same as the first embodiment, so that for a more detailed description of the second embodiment reference should be made to the description of the first embodiment.

INDEXES

(12) 1 Ball joint 2 Joint ball 3 Ball pin 4 Ball socket 5 First ball socket component 6 Second ball socket component 7 Axial direction 8 Pin opening in the ball socket 9 Joint housing 10 Pin opening in the joint housing 11 Pressure element 12 Spring 13 Moving part of the actuator 14 Actuator 15 Static part on the actuator 16 Control unit 17 Emitter element 18 Sensor element 19 Displacement sensor 20 Evaluation unit 21 Pin portion of the ball pin 22 Axial housing abutment 23 Cover 24 Rim of the housing 25 First housing component 26 Second housing component 27 Thread d Distance/spring length F Spring force/axial force