EP1784580A1

EP1784580A1 - Ball-and-socket joint

Info

Publication number: EP1784580A1
Application number: EP05779609A
Authority: EP
Inventors: Frank Budde; Thomas Richter
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2004-09-02
Filing date: 2005-08-24
Publication date: 2007-05-16
Also published as: ZA200702584B; JP2008511798A; WO2006024270A1; US20080138150A1; CN101048606B; DE102004042965A1; DE102004042965B4; CN101048606A; KR20070054199A; MX2007002497A; BRPI0514863A

Abstract

Disclosed is a ball-and-socket joint for a motor vehicle, particularly a pivoted support of a motor vehicle. Said ball-and-socket joint comprises a housing (1) which is open at least on one side and inside which a bearing shell is inserted that slidingly accommodates a ball of a ball pin. According to a first embodiment, the interior of the housing (1) is provided with elevations along the inner circumferential surface thereof. Said elevations are configured as triangular webs (13) and positively engage into the bearing shell. According to a second embodiment, the interior is provided with recesses along the inner circumferential surface thereof, the bearing shell positively engaging into said recesses that are configured as undercuts.

Description

ball joint

description

The present invention relates to a ball joint for a motor vehicle, in particular for a pendulum support of a motor vehicle, with a housing open at least on one side, in the interior of a bearing shell is inserted, which in turn receives a ball joint of a ball pin slidably.

From DE 43 06 006 Al a ball joint with an annular housing and a bearing shell inserted therein is known, in which a ball pin is mounted. The bearing shell has at its outer periphery a contour which engages for securing against rotational movements about the ball pivot central axis in a complementary contour of the housing inner diameter.

In ball joints from the prior art, it happens, however, that the contour of the bearing shell with increasing use of the ball joint of the complementary contour of the housing dissolves, so that the rotation can fail.

The object of the invention is therefore to provide a ball joint of the type mentioned, in which the rotation against the prior art is improved. According to the invention this object is achieved according to a first variant with a ball joint having the features of claim 1 and according to a second variant with a ball joint having the features of claim 11.

According to the first variant, a ball joint for a motor vehicle, in particular for a pendulum support of a motor vehicle is provided with a housing open at least on one side, in the interior of a bearing shell is used, which in turn receives a ball joint of a ball pin slidably receiving, wherein the interior along its inner circumferential surface elevations has, which engage positively in the bearing shell. The elevations are designed as triangular webs.

In the bearing shell according to the invention twisting is reliably prevented, because it has been shown that a Los wobbling of the shell does not occur from the housing. The ball joint according to the invention can be produced inexpensively in the series process, wherein an improvement of the rotation against the prior art is given.

The triangular webs can be inclined to the longitudinal center axis, z. B. along a zig-zag line. Preferably, however, the triangular webs extend parallel to the longitudinal center axis of the housing, whereby a particularly simple installation of the ball joint by pressing the bearing shell into the interior under plastic deformation of the outer circumferential surface is possible.

The triangular webs can extend over only a part of the length of the inner lateral surface of the housing, but preferably the triangular webs extend over the entire length of the inner circumferential surface of the housing. As a result, particularly large moments between bearing shell and housing can be transferred.

The triangular webs may have the shape of a skewed triangle in cross section. Preferably, however, the triangular webs are each formed with two equal leg surfaces, wherein the bisector of the enclosed between the two same leg surfaces angle passes through the longitudinal center axis of the bearing. According to this embodiment, it is ensured that the anti-rotation device acts equally with respect to both possible directions of rotation about the longitudinal center axis.

The radial height of the triangular webs may be varied according to the use and loading of the ball joint. However, a particularly good anti-rotation has been achieved when the radial height of the triangular webs is equal to the product of the shell thickness of the bearing shell and the elongation at break of the material used for the bearing shell.

Preferably, a right angle is included by the two same leg surfaces of each triangle bar. A larger opening angle could promote slippage of the bearing shell from the triangular webs, whereas a smaller angle could increase the notch sensitivity of the bearing shell material. Nevertheless, of course, other opening angles are possible, provided that use and load of the ball joint allow this.

In principle, any number of webs of triangular webs is possible in order to form the anti-twist device according to the invention. However, it has been shown that this number nsteg becomes optimal if it is greater than or equal to the even-rounded quotient of the maximum torque MTmax and the product of the area of the webs Asteg, the shear strength σsmax of the bearing shell material and the effective bearing shell radius r. This results in:

nsteg »Mtmax / (Asteg * σSmax * T)

In this case, the effective bearing shell radius r extends from the ball center to a region between the inner edge and the outer edge of the bearing shell, wherein the radius is referred to the inner edge of the bearing shell with grooves and the radius to the outer edge of the bearing shell with rOußen. Thus, the following relationship applies to the effective bearing shell radius r:

troughs ≤ V ≤ r outside,

the optimum value of r being dependent on the depth to which the triangular webs engage in the bearing shell. A good value for r has been found when r = rAußen is chosen.

Preferably, the bearing shell made of plastic, in particular made of polyoxymethylene, wherein the bearing shell can be introduced under plastic deformation of its outer peripheral surface in the housing, unless the bearing shell is not provided with the recesses before assembly, in which the triangular webs in the assembled state of the ball joint intervention.

In principle, there may be a gap between the outer circumferential surface of the bearing shell and the inner lateral surface of the housing. However, the bearing shell preferably has a slight oversize with regard to the inner circumferential surface of the housing so that it sits under slight radial pressure in the housing. As a result, the air gap can be avoided and thus the penetration of dirt can be prevented.

According to the second variant of the invention, a ball joint for a motor vehicle, in particular for a pendulum support of a motor vehicle is provided, with a housing open at least on one side, in the interior of a bearing shell is inserted, which in turn receives a ball joint of a ball pin slidably, the interior along its Inner circumferential surface has recesses into which the bearing shell engages positively. The depressions are formed as undercuts.

Even after this variant, a Los wobbling of the bearing shell is prevented by the housing, whereby a particularly good and durable rotation is formed. As in the first variant, the ball joint according to the second variant can be produced inexpensively in a series process.

The undercuts can be oblique to the longitudinal center axis, z. B. along a zigzag line. Preferably, however, the undercuts extend parallel to the longitudinal center axis of the housing, whereby a particularly simple mounting of the ball joint is possible.

In principle, the depressions can extend over the entire length of the inner lateral surface of the housing. However, a sufficient security against rotation already arises when the recesses open towards an end face of the housing extend only over part of the length of the inner circumferential surface. It has proved to be advantageous if the recesses with respect to a longitudinal section of the housing have a rectangular or triangular profile. The bearing shell is preferably made of plastic, in particular of polyoxymethylene, wherein the bearing shell can be formed by ultrasonic deformation into the recess.

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

1 shows a longitudinal section through a first embodiment of the ball joint according to the invention in the partially assembled state.

FIG. 2 shows a longitudinal section of the embodiment according to FIG. 1 in the fully assembled state; FIG.

3 shows a cross section of the housing according to the first embodiment according to the first variant of the invention;

4 shows the cross section of a triangular web according to FIG. 3;

5 shows the longitudinal section of the housing according to FIG. 3 along the sectional area A-A ';

FIG. 6 shows the cross section of the housing according to FIG. 3 with inserted calibration tool; FIG.

7 shows the cross section of a housing according to a second embodiment according to the second variant of the invention;

Fig. 8: the enlarged view of an undercut of FIG. 7 with an engaging projection of the bearing shell and 9 shows a longitudinal section through the housing according to FIG. 7 along the sectional surface B-B ', wherein two sub-variants for the profile of the undercut are shown.

1, a bearing shell 2 is used in an annular housing 1, in which a pin 3 and a ball joint 4 having ball pin 5 is slidably mounted. In this case, the ball pin 5 extends through an opening provided in the bearing shell 2 opening 6 out of the ball joint and can be rotated about the longitudinal center axis 7 of the ball joint and pivoted transversely to this about a pivot point in the ball joint 4. In the region of the opening 6, the bearing shell 2 rests against an end face of the housing 1 via an outer shoulder 8, whereas an annular collar 9 protrudes from the housing 1 at the end of the bearing shell 2 facing away from the outer shoulder 8.

From Fig. 2 it can be seen that the annular collar 9 has been allocated for axially fixing the bearing shell 2 in the housing 1 by material deformation radially outward, wherein the folding is preferably carried out using the method of ultrasonic deformation. The ball and socket joint according to this embodiment is designed to transmit a maximum torque Mtmax between housing 1 and bearing shell 2 of 15 Nm, wherein the bearing shell made of POM has a shell thickness Sd of 1.5 mm and an elastic elongation εs of approximately 10%. Another embodiment may also be designed to transmit a maximum torque Mtmax between the housing 1 and bearing shell 2 of 20 Nm.

The housing 1 is formed integrally with a first motor vehicle part 10, wherein the pin 3, a threaded portion 11 for securing a second Motor vehicle part is provided. To prevent ingress of dirt and moisture into the interior of the ball joint, between the ball stud 5 and the bearing shell 2, a seal 12 made of an elastic material, in particular made of rubber, said seal 12 but also between the ball stud 5 and the Housing 1 can be arranged.

In Fig. 3 the provided according to the first variant of the invention triangular webs 13 are shown, which are formed on the inner circumferential surface of the housing 1. The triangular webs 13 extend parallel to the longitudinal center axis 7 over the entire length Ig of the housing 1 (see FIGS. 1 and 5), which according to this embodiment is 10 mm.

The cross section of a triangular web 13 is shown in an enlarged view of FIG. 4, wherein between the two same leg surfaces 14 and 15 of the triangular web 13 an angle α with α = 90 ° is included. The bisector 16 of the angle α extends through the central longitudinal axis 7 of the ball joint, wherein the triangular web 13 has a radial height hd of 0.15 mm, which consists of the product of shell thickness Sd (1.5 mm] and yield strain εs (10%) results.

Regularly, the ball joint housing 1 must be calibrated after its manufacture, that is, be extended to the correct diameter. For this purpose, a calibration tool 18 shown in FIG. 6 and composed of a plurality of segments 17 is used. The calibration tool 18 has at its center a through hole 19, through which a conical mandrel (not shown) can be driven for radially pushing apart the segments 17. However, there is the danger that the triangular webs 13 can be destroyed. For this reason, the calibration tool 18 can be formed such that it touches the inner circumferential surface of the housing 1 only in certain places, so that only At these points extending triangular webs 13 can be destroyed. According to FIG. 6, the calibration tool 18 touches the inner lateral surface of the housing 1 at eight points, so that only eight of the sixteen triangular webs 13 present here can be destroyed during calibration. In the event that sixteen triangular webs are to be present in the calibrated housing 1, therefore, for safety reasons, twenty-four triangular webs 13 must be formed in the housing 1 before being calibrated.

Of course, the number of triangular webs 13 and the number of contact points of the calibration tool 18 on the housing 1 can be varied. However, sixteen triangular webs are ideal after calibration at an effective bearing shell radius of r = 9.5 mm.

Following the calibration, the bearing shell 2 formed with a slight oversize with respect to the inner circumferential surface of the housing 1 is introduced into the housing 1, so that the triangular webs 13 dig into the housing shell 2 with plastic deformation of the outer circumferential surface. In this way, a particularly effective anti-rotation of the bearing shell 2 relative to the housing 1 is formed, which also prevents penetration of dirt and moisture in the area between the bearing shell 2 and ball joint housing 1 due to a small oversize of the bearing shell 2 before mounting.

From Fig. 7 is a cross section of a housing 1 according to a second embodiment according to the second variant of the invention can be seen, for the same or similar features the same reference numerals as in the first embodiment are used. Furthermore, the second embodiment also corresponds to a ball joint according to FIGS. 1 and 2, wherein, however, along the inner circumferential surface of the housing 1 no triangular webs a total of sixteen extending parallel to the longitudinal center axis 7 extending undercuts 20 are provided, in which the bearing shell 2 engages to form the anti-rotation.

An enlarged view of such an undercut 20 is shown in FIG. 8, wherein the bearing shell 2 engages with a projection 21 in this undercut 20. The undercuts 20 are open towards an end face of the housing 1 and do not extend over the entire length Ig of the inner circumferential surface of the housing 1, but only over a partial length It, which is shown in Fig. 9. The rotation between the bearing shell 2 and housing 1 is now formed such that the projecting in the partially assembled state from the housing 1 annular collar 9 of the bearing shell 2 is folded over a forming process radially outwards and simultaneously formed in the undercuts 20. In particular, an ultrasonic forming method is used for this, wherein the material of the bearing shell 2 is heated. After forming, it comes during the cooling of the bearing shell material to a so-called Mate riaisch winding, which causes the molded into the undercuts 20 projections 21 of the bearing shell 2 pull radially inwardly against the side walls 22 and 23 of the undercuts 20, whereby a permanently good rotation of the bearing shell 2 relative to the housing 1 is formed.

As shown schematically in FIG. 9, the undercuts 20 may have a rectangular profile (24) or a triangular profile (25) with respect to a longitudinal section of the housing (1) along the sectional area BB 'shown in FIG. Although only sixteen undercuts 20 are shown according to this embodiment, a particularly good anti-rotation has resulted in the formation of twenty-four undercuts.

Analogous to the first variant, according to the second variant of the invention, the bearing shell 2 may be formed with a slight excess in terms of the inner peripheral surface of the housing 1 prior to assembly, so that dirt and water can be prevented from penetrating into the region between the bearing shell 2 and the housing 1 can.

Both variants of the invention prevent so-called loose-rolling of the bearing shell 2 from the housing 1. In the first variant, the bearing shell can be introduced into the interior of the housing 1 under plastic deformation of its outer peripheral surface. Since this deformation can take place without particular material heating, a shrinkage of the bearing shell material is avoidable, which could favor a loose shaking of the bearing shell 2. Furthermore, no oversize of the outer diameter of the bearing shell 2 relative to the inner diameter of the housing 1 is required. However, a slight oversize can be advantageous in order to achieve a sealing effect between the bearing shell 2 and the housing 1. Therefore, the bearing shell 2 can be introduced without or with only a very small radial bias in the housing 1, so that the undesirable effects of a large radial bias can be avoided, which can adversely affect the friction moments of the ball stud in the bearing shell. Furthermore, such a large radial bias due to the behavior of the plastic is time-dependent, so that a time dependence of the friction moments of the ball stud can be adjusted solely due to the high bias. This negative effect can be avoided with the ball joint according to the invention. In the second variant, the projections 21 of the bearing shell 2 pull due to the shrinkage of the Bearing material after forming firmly into the undercuts 20, so that the effect of shrinkage does not contribute to deterioration but to improve the anti-rotation.

LIST OF REFERENCE NUMBERS

casing

bearing shell

spigot

joint ball

ball pin

Opening in the bearing shell

Longitudinal central axis

outer shoulder

Ring collar first motor vehicle part

thread

bellows

Triangular web first leg surface of the triangular web second leg surface of the triangular web

bisecting

Segments of the calibration tool

calibration

Bore in calibration tool

undercut

Projection of the bearing shell first side wall of the undercut second side wall of the undercut rectangular profile triangular profile Ig length of the housing hd radial height of the triangle webs

Sd thickness of the bearing shell r effective bearing shell radius α angle

It length of the undercut (partial length)

Claims

Ball joint patent claims

1. Ball joint for a motor vehicle, in particular for a pendulum support of a motor vehicle, with a housing (1) which is open at least on one side, in the interior of which a bearing shell (2) is inserted, which in turn slidably receives a ball joint (4) of a ball stud (5), characterized in that the interior along its inner circumferential surface has elevations which engage in a form-fitting manner in the bearing shell (2), wherein the elevations are formed as triangular webs (13).

2. Ball joint according to claim 1, characterized in that extending the triangular webs (13) parallel to the longitudinal center axis (7) of the housing (L).

3. Ball joint according to claim 1 or 2, characterized in that the triangular webs (13) over the entire length (Ig) of the inner surface of the housing surface (L) extend.

4. Ball joint according to one of the preceding claims, characterized in that the triangular webs (13) are each formed with two equal leg surfaces (14, 15) and the bisector (16) of the between the two same leg surfaces (14, 15) enclosed angle ( α) extends through the longitudinal center axis (7) of the bearing.

5. Ball joint according to claim 4, characterized in that the radial height (hd) of the triangular webs ¹ (13) is equal to the product of the shell thickness (Sd) of the bearing shell (2) and the elongation at break of the material used for the bearing shell (2) ,

6. Ball joint according to claim 3 or 4, characterized in that of the two same leg surfaces (14, 15) of each triangular web (13) a right angle (α) is included.

7. Ball joint according to one of the preceding claims, characterized in that the number of triangular webs (13) greater than or equal to the even-rounded quotient of the maximum between the housing (1) and the bearing shell (2) to be transmitted moment and the product of the Area of the triangular webs (13), the shear strength of the bearing shell material and the effective bearing shell radius (r).

8. Ball joint according to one of the preceding claims, characterized in that the bearing shell (2) is made of plastic.

9. Ball joint according to claim 8, characterized in that the bearing shell (2) made of polyoxymethylene (POM) is made.

10. Ball joint according to one of the preceding claims, characterized in that the bearing shell (2) has an oversize relative to the inner circumferential surface of the housing (1).

11. Ball joint for a motor vehicle, in particular for a pendulum support of a motor vehicle, with a housing (1) which is open at least on one side, in the interior of which a bearing shell (2) is inserted which in turn slidably receives a joint ball (4) of a ball stud (5), characterized in that the interior along its inner circumferential surface has recesses into which the bearing shell (2) engages positively, wherein the recesses are formed as undercuts (20).

12. Ball joint according to claim 11, characterized in that the undercuts (20) extend parallel to the longitudinal center axis (7) of the housing (1).

13. Ball joint according to claim 11 or 12, characterized in that the to an end face of the housing (1) open towards undercuts (2) only over a part (It) of the length (Ig) of the inner circumferential surface of the housing (1).

14. Ball joint according to claim 13, characterized in that the undercuts (20) with respect to a longitudinal section of the housing (1) have a rectangular profile (24) or a triangular profile (25).

15. Ball joint according to one of the preceding claims 11 to 14, characterized in that the bearing shell (2) is made of plastic.

16. Ball joint according to claim 15, characterized in that the bearing shell made of polyoxymethylene (POM) is made.

17. Ball joint according to claim 15 or 16, characterized in that the plastic is suitable for ultrasonic deformation.