Joints and connections – Articulated members – Pivoted
Reexamination Certificate
1998-10-28
2001-09-11
Browne, Lynne H. (Department: 3629)
Joints and connections
Articulated members
Pivoted
C277S635000, C403S132000
Reexamination Certificate
active
06287040
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a ball-and-socket joint for motor vehicles.
BACKGROUND OF THE INVENTION
Various designs of such ball-and-socket joints have been known. They are used, e.g., as support joints or as guiding joints in the area of the wheel suspension. These types of joints have a housing open on one side, into which a one-part or multipart bearing shell is inserted. The joint ball of a ball pivot, which exits from the housing side that is open on one side and which is provided with a connection contour on the side located opposite the joint ball, is accommodated within the bearing shell movably in all directions.
For example, threads or fits, which may in turn be combined with grooves milled in the ball pivot, are used as the connection contour in the known manner. A bolt inserted into the wheel carrier engages this groove, and the bolt thus acts as a captivating means.
A sealing element in the form of a bellows, which surrounds the ball pivot, on the one hand, and is sealingly fixed at the housing of the ball-and-socket joint, on the other hand, is usually used as a sealing means for the ball-and-socket joint. To improve the sealing function, clamping rings may be additionally provided at the sealing element. Moreover, it has been known that the contact areas of the sealing element with the housing or the ball pivot may be provided with complementary, labyrinth-like contours.
DE 41 12 791 C1 describes, e.g., an axle strut joint with a joint housing, in which a pivotably movable ball pivot, which is formed by a ball body and two pivot projections projecting from same on diametrically opposed sides, is mounted with the interposition of at least one bearing shell. The pivot projections pass through openings of the housing. One sealing bellows each is arranged in the area of each opening of the housing between the joint housing, on the one hand, and the corresponding pivot projection, on the other hand. The housing-side edge area of each sealing bellows is held at the inner wall of the housing by means of a clamping ring, and the clamping ring is supported at a ring projection of the housing, which forms the edge of the opening of the housing and is directed inwardly. The clamping ring has an L-shaped design and is equipped with a first leg, which extends essentially in the axial direction of the housing and is springily elastic in the radial direction, and with a second leg, which extends approximately at right angles thereto, and is fastened on the side of the sealing bellows that is the outer side relative to the sealed inner wall of the housing, at its edge area having a correspondingly L-shaped profile.
This joint has the peculiarity that the ball pivot projects from the joint housing on both sides.
The drawback of such a ball-and-socket joint is, however, that besides its complicated design, it cannot assume an optimal sealing function over a long life cycle. An annular groove, into which the sealing bellows is inserted, is milled in the pivot.
The sealing bellows is in contact in this annular groove with the ball pivot under pretension, which is additionally increased by a clamping ring. However, there is a risk at this connection point of the components that contaminants may be deposited. These may be, e.g., detergents, oil residues or salt-containing solutions, which frequently occur during the operation of a vehicle during the wintertime. Thus, highly corrosive media sometimes enter this area of the ball-and-socket joint and they gradually lead to corrosion phenomena on the ball pivot, and this corrosion in turn facilitates the penetration of contaminants or moisture due to increasing porosity of the surface. The inevitable consequence is the accelerated destruction of the joint.
SUMMARY AND OBJECTS OF THE INVENTION
The basic technical problem to be solved by the present invention is to develop a ball-and-socket joint that prevents the deposit of contaminants at the connection point between the sealing element and the ball pivot and thus protects the ball pivot in this area from corrosion as well as the inner components of the joint from the penetration of moisture and contaminants, so that the service life of such a ball-and-socket joint is prolonged.
According to the invention, a ball-and-socket joint is provided for motor vehicles. The joint includes a housing, a bearing shell, which is inserted into the housing. The bearing shell accommodates the joint ball of at least one ball pivot projecting, from the housing on at least one side, movably in all directions. The ball pivot is provided with a connection contour on the end side, as well as a sealing element in the form of bellows. The bellows sealing element is in sealing contact with the housing, on the one hand, and with a shoulder of the ball pivot, on the other hand. A circular ring collar is made in one piece with the ball pivot. The ring collar is provided with a markedly undercut contour and the sealing element is inserted under elastic pretension into the annular space formed by the undercut with an area that is in sealing contact with the ball pivot.
It is proposed according to the present invention that a circular ring collar, provided with an undercut contour, be made in one piece with the ball pivot. The sealing element with its area in sealing contact with the ball pivot is inserted according to the present invention under elastic pretension into the annular space at the ball pivot shaft, which annular space is formed by the undercut and is located radially on the inside, so that the circular ring collar covers the edge area of the sealing element.
It is achieved due to such a design of a ball pivot that contaminants are no longer able to settle at the ball pivot or in the contact area between the ball pivot and the sealing element.
The free surface of the ring collar should therefore be made as flat as possible. The ring collar may be made in one piece with the ball pivot or may be recessed from it according to prior-art processes. Thus, a subsequent machining of the ball pivot is just as conceivable as manufacturing in one piece according to a cold flow process, or, e.g., a subsequent deformation of an originally radially extending ring collar made in one piece with the ball pivot.
A ball-and-socket joint according to the present invention may consequently be a guiding joint provided with a housing that is open on one side. According to the present invention, the ring collar has a contour of a hook-shaped cross section, whose pointed edge area points in the direction of the joint ball of the ball pivot.
A guiding joint is known to be equipped with a housing that is open on one side. The ball pivot is in a so-called “upright” arrangement, i.e., it is inserted into the wheel carrier from the bottom. The contaminants or the splash water reach the ball-and-socket joint from the fastening side of the ball pivot in the wheel carrier. It is for this reason that the circular ring collar is made in one piece with the ball pivot in the above-described manner. A possibility of drainage is thus provided via the ring collar, which is provided with a smooth surface on the outside, and the sealing element, and this additionally effectively prevents the contaminants from hardening.
In addition, contours of the ring collar, which have, e.g., a U-, L-, V-shaped or similar cross geometry when viewed in the cross section, are also within the scope of the present invention.
According to another embodiment of a ball-and-socket joint according to the present invention, the sealing element has a reinforced bead in the contact area of the ball pivot, and this bead is inserted into the annular space of the ring collar formed by the undercut. Moreover, the pretension of the sealing element may be increased by at least one additional tensioning means.
Clamping rings may be used as tensioning means in the known manner.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a bette
Browne Lynne H.
McGlew and Tuttle , P.C.
Walsh John B.
ZF Lemforder Metallwaren AG
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