The invention concerns a ball joint with a ball stud having a spherical bearing area, which with the bearing area is fitted and able to move by sliding in a ball socket and, with this, is arranged in an opening of a holder, and a solid body formed by injection molding a solidifiable material around the ball socket and the holder, from which the ball stud projects outward in an axial direction.
The structure and assembly of ball joints designed as radial joints are based on the positioning and joining together of individual components (ball stud, ball socket, housing, sealing bellows, etc.) in individual processes and production steps. The function and properties of the radial joint as a whole are determined by the respective tolerance characteristics of the individual components and are optimized by finishing processes (tempering, grinding, etc.) in order to meet the customers' requirements.
EP 0 927 310 B1 discloses a ball joint with a ball joint housing comprising a tubular wall portion, which extends substantially coaxially with the ball stud that projects outward and carries the ball, and which surrounds the ball a distance away from it, wherein, when the ball has been inserted, a housing material fills the empty space between the wall portion and the ball, surrounding the ball in such manner that the ball is mounted and able to move within the housing material by rotating in a hollow that surrounds the ball around more than its half-shell. The tubular wall portion consists of a tubular profile section with inward-facing and outward-facing anchoring elements, such that the cast-in or injection-molded housing material fills only the free space between the tubular profile section and the ball, extending through but not beyond the full length of the tubular portion so that the tubular portion form the whole of the radial outer wall of the ball joint housing. In addition, an intermediate bearing layer is interposed between the hollow and the ball.
When acted upon by large axial loads this ball joint has insufficient strength to resist being pulled apart.
Starting from there, the purpose of the present invention is to provide a ball joint of the type described to begin with, which has relatively high pull-apart resistance.
The ball joint according to the invention, in particular for a motor vehicle, comprises a ball stud having a spherical bearing area, which with the bearing area is fitted and able to move by sliding in a ball socket and, with the latter, is arranged in an opening of a holder, and comprises also a solid body formed by injection-molding a solidifiable material around the ball socket and the holder, from which the ball stud projects outward in an axial direction, such that in the solid body axial retaining means for the ball stud that cover the ball socket axially and are encapsulated by the material are provided.
By virtue of the axial retaining means integrated in the solid body by injection molding so as to cover the ball socket, the resistance of the ball joint against being pulled apart is increased.
According to a first embodiment of the invention, the axial retaining means are formed by rim sections of the holder covering the ball socket axially, which are preferably arranged around a rim of the holder's opening that surrounds the ball socket. Preferably, the rim sections extend alternately in opposite directions. In particular, the rim sections are inclined relative to the axial direction so that, preferably, they cover the ball socket with their free ends. Yet, the rim sections preferably run substantially in the axial direction. The rim sections can be made as separate components and attached to the holder. However, they preferably form a material unit with the holder. In particular, the rim sections are bent away from the holder.
According to a second, alternative embodiment of the invention the axial retaining means are formed by a pot-shaped container, in which the ball stud with the ball socket is seated. In this case the ball stud extends out of the container, in particular through a container opening, preferably in the axial direction. Preferably, at least in parts the rim of the container around its opening is bent radially inward toward the ball stud so that the rim covers the ball socket axially.
Preferably, the container extends through the opening of the holder. In particular, the container is axially secured onto the holder by the solid body. Preferably, and in particular on the side of the holder facing away from the container's opening, the container has a circular, radial projection whose outer diameter is larger then the diameter of the holder's opening. In this way the container is additionally secured axially in the holder.
In a further development of the invention, the solid body has a fixing extension formed during the injection of the material, which has an annular groove onto which a sealing bellows can be or is fixed. Preferably, the sealing bellows extends as far as the ball stud, in particular as far as a shank section thereof.
The ball socket can be injection-molded onto the bearing area. However, the ball socket is preferably formed as a separate component, in particular one which is snap-fitted onto the bearing area.
Preferably, the ball stud and/or the holder are each made of metal, in particular steel. For example, the holder can be a sheet component. The ball socket consists in particular of plastic, preferably polyoxymethylene (POM). The container, when present, is preferably made of metal, in particular steel. The solidifiable material consists for example of plastic or metal. In particular the solidifiable material consists of zinc, aluminum, magnesium or a fiber-reinforced polyamide such as PA66 GF30.
The bearing area has a preferably spherical bearing surface, which is preferably in contact with a preferably hollow spherical surface of the ball socket. Connected to the bearing area the ball stud comprises in particular a shank section, which projects out of the ball socket, the solid body and the container if present.
The holder surrounds the bearing area, in particular up to the level of its equator, so that radial forces can be transmitted effectively between the ball stud and the holder. Preferably the holder has an annular section around its opening, which is preferably flat. Preferably, the holder is a chassis component or part thereof. For example, the chassis component can be a control arm or a wheel carrier.
In particular, the ball joint according to the invention is designed as a radial joint and preferably comprises a reduced number of components. In particular, the ball joint according to the invention can be made with fewer assembly processes. By joining the pre-assembled ball stud with its ball socket and housing by means of the injection-molding process (with plastic, zinc, aluminum, etc.) the ball joint is preferably made as a complete joint cartridge. The term “housing” is in particular understood to mean the holder or the assembly consisting of the holder and the container. Thereafter, the ball joint is completed by fitting the sealing system comprising the sealing bellows. To improve force transmission, the housing is in particular designed such that the ball socket and/or the assembly consisting of the ball stud and the ball socket is supported in both the axial and radial directions. The holding fixture for the sealing system is formed either by the housing, and/or wholly or partially by the injected material, preferably in the form of the fixing extension. Preferably the housing comprises the axial retaining means. Depending on the view adopted, the housing can also comprise the solid body.
The ball joint according to the invention can be used with current, radially loaded products or chassis components, for example as a flange joint, a control arm joint or an external joint. Its performance can be improved by additional elements (for example, the pull-out force can be increased). The performance in the axial and radial loading directions can be strengthened/increased, for example by incorporating the container.
In particular, the following advantages are obtained:
Below, the invention is described with reference to preferred embodiments illustrated in the drawing, which shows:
The assembly consisting of the ball stud 2, the ball socket 4 and the holder 6 now has injected around it a solidifiable material which, after it has solidified, forms a solid body 12 which is shown as transparent in
The assembly consisting of the ball stud 2, the ball socket 4, the container 20 and the holder 6 is encapsulated by injection-molding around it a solidifiable material, which when it has solidified, forms a solid body 12 represented as transparent in
1 Ball joint
2 Ball stud
3 Bearing area of the ball stud/joint ball
4 Ball socket
5 Through-going opening in the holder
6 Holder
7 Rim section
8 Rim section
9 Rim section
10 Rim section
11 Axial direction of the ball joint
12 Solid body
13 Contour line of the solid body
14 Fixing extension
15 Annular groove
16 Sealing bellows
17 Free end of the ball stud
18 Recess
19 Key surface
20 Container
21 Opening of the container
22 Circular radial projection
24 Shank area of the ball stud
Number | Date | Country | Kind |
---|---|---|---|
10 2010 041 304.6 | Sep 2010 | DE | national |
This application is a National Stage completion of PCT/EP2011/064590 filed Aug. 25, 2011, which claims priority from German patent application serial no. 10 2010 041 304.6 filed Sep. 24, 2010.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP11/64590 | 8/25/2011 | WO | 00 | 3/13/2013 |