Joints and connections – Articulated members – Pivoted
Reexamination Certificate
1998-11-25
2001-04-10
Kim, Harry C. (Department: 3629)
Joints and connections
Articulated members
Pivoted
C403S132000, C403S140000, C029S898047
Reexamination Certificate
active
06213675
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to an axial joint, especially an axial joint used in automotive engineering, especially in the area of the steering and shifting of a vehicle.
BACKGROUND OF THE INVENTION
A similar axial joint has been known from EP 0 026 864 B1. This patent specification discloses an axial joint, whose task it is to have a low frictional resistance for relatively small movements and a relatively higher frictional resistance for large movements. This axial joint comprises a two-part metallic housing with a cylindrically spherical interior space and two openings along the cylindrical axis. A ball pivot with a joint ball and a pin are located within the housing, and the joint ball is surrounded by the housing and the pin projects from the housing through the smaller of the openings, which are located in the area of the spherical part of the housing. A large opening, through which the ball pivot can be introduced into the interior of the housing, is arranged in the cylindrical area of the housing. A two-part bearing shell is provided between the housing and the ball pivot over an essential part of the surface. The bearing shell ensures easy mobility of the ball pivot or a varying mobility in the embodiment shown there, depending on the deflection of the ball pivot. One part of the bearing shell is made spherical both on the inside and on the outside, while the second part of the bearing shell is made cylindrical in the outer area, corresponding to the metallic housing, and it has a spherical design in the inner area, corresponding to the surface of the joint ball of the ball pivot.
When manufacturing the ball pivot, the ball pivot is introduced after inserting the spherical part of the bearing shell into the housing. The cylindrically spherical bearing shell is then placed on the ball pivot in the cylindrical part and an essentially flat cover is fitted onto the cylindrical part of the housing such that it presses the two bearing shells firmly into the housing and around the joint ball of the ball pivot.
One drawback of this prior-art design of an axial joint is that the manufacture of this axial joint, comprising a plurality of parts, is relatively complicated. Furthermore, it is problematic in this design to provide a good connection between the housing and a vehicle part on the side opposite the pivot of the ball-and-socket joint.
SUMMARY AND OBJECTS OF THE INVENTION
The primary object of the present invention is to manufacture an axial joint, especially for use in the manufacture of a chassis, and especially for use in the manufacture of shifting and steering means, in which the drawbacks of the state of the art are avoided. Another object of the present invention is to describe a simple process for manufacturing this axial joint according to the present invention.
According to the invention, an axial joint is provided which comprises a metallic housing with an opening and an interior space as well as a ball pivot with a joint ball. The ball pivot has a pivot neck between its pivot pin and the joint ball and the joint ball is surrounded for the most part by the housing. The pivot pin projects through the opening of the housing. At least one bearing shell, made essentially of plastic, is arranged between the housing and the joint ball. The housing is metallic and made in one piece.
This one-piece design offers the inherent advantage that a substantially simpler and less expensive manufacture is made possible compared with the state of the art.
According to a variant of the object of the present invention, the axial joint may be shaped such that after the mounting of the axial joint, the diameter of the joint ball is substantially larger than the diameter of the opening of the housing, and the latter is in turn substantially smaller than the axial extension of the pivot neck. It is achieved as a result that a current weak point of axial joints, namely, the insufficient ability to transmit a tensile force along the axis of the ball pivot, is improved. In addition, it is achieved due to the design of the ball-and-socket joint according to the present invention that the angular deflections of the ball pivot in the ball-and-socket joint can also be increased.
According to another variant of the axial joint according to the present invention, the bearing shell may be made of two parts, and, in an additional variant, at least one part of the bearing shell, preferably the one located closest to the opening of the housing, may be made of a plastic-metal composite. It is achieved as a result that a substantially more favorable production is possible and that commercially available parts may also be used for the bearing shell, especially for the cylindrical area or for the originally cylindrical area. Furthermore, a substantially higher load-bearing capacity of a joint according to the present invention, a considerable weight reduction, and improved temperature stability are achieved compared with prior-art axial joint designs. The improved temperature stability of the composite bearing shell reduces the adverse effects of temperature-dependent component tolerances, so that a favorable effect on the frictional properties of the components of the joint is obtained as a result. Nearly constant friction is achieved.
According to another variant of the axial joint according to the present invention, a damping ring, which may consist of, e.g., rubber or another elastomer, is inserted between the bearing shell and the housing. A possible transmission of vibrations from the bearing shell to the ball pivot and vice versa is reduced by means of this damping ring. In addition, such a damping ring generates a pretension as a secondary effect, i.e., a constant pressing of the bearing shell against the joint ball, so that vibrations, which could be generated by an undesirable clearance in the axial joint, are avoided.
In another embodiment of the axial joint, a housing pin is provided at the housing, which is made in one piece according to the present invention. This housing pin may be arranged, e.g., opposite the opening of the housing, i.e., opposite the projecting pivot of the ball pivot. Simple connection of the ball-and-socket joint to a vehicle part is possible as a result. The housing pin may also be provided, e.g., with a connection contour, such as threads, so that the axial joint can be screwed directly into another threaded hole.
Corresponding to another idea of the present invention, the axial joint is manufactured by cold forming an initially cylindrical part of the housing around the joint ball with a bearing shell arranged between the housing and the joint ball. This process makes it advantageously possible to manufacture an axial joint with a one-piece housing, which can also absorb tensile forces and in which welding of the housing is not necessary.
According to another feature of the present invention, a process for manufacturing an axial joint with the following process steps is disclosed:
1. Insertion of a bearing shell, which is cylindrical over its essential part, into a one-piece metallic housing, which is likewise cylindrical over its essential part and has an opening on one side,
2. insertion of a preferably metallic joint ball of a ball pivot into the hollow space of the bearing shell, and
3. cold forming of an essentially cylindrical part of the housing, so that an essential part of the initially cylindrical part of the bearing shell and of the initially cylindrical part of the housing fits the outer contour of the joint ball.
It is obvious that the above-mentioned features of the present invention, which will be explained below, can be used not only in the particular combination described, but also in other combinations or alone without going beyond the scope of the present invention.
Additional features and advantages of the present invention appear from the following description of preferred exemplary embodiment with reference to the drawings.
The various features of novelty which characterize the invention are pointed out with parti
Hüneke Gerhard
Muller Dieter
Schmudde Norbert
Ungruh Rainer
Kim Harry C.
McGlew and Tuttle , P.C.
ZF Lemforder Metallwaren AG
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