Joints and connections – Articulated members – Pivoted
Patent
1994-12-15
1996-09-03
Johnson, Blair
Joints and connections
Articulated members
Pivoted
403138, 403122, 403124, F16C 1100, F16D 112
Patent
active
055517919
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is the U.S. national phase of PCT application PCT/DE94/00336 filed Mar. 23, 1994 with a claim to the priority of 23 Mar. 1994. German patent application G 93 04 897.1 filed 31 Mar. 1993.
1. Field of the Invention
The present invention relates to a ball joint. More particularly this invention concerns a ball joint having a housing forming a cavity, a ball in the housing, a stem fixed to the ball and extending downward out of the housing, a rigid cover fixed in the housing and upwardly closing the cavity over the ball, and a compression spring engaged between an upper region of the ball and the housing.
2. Background of the Invention
Such ball joints are used mainly in motor vehicles, for example in steering systems for small trucks, buses, and heavy trucks. In order to eliminate play from the joint a conical coil spring is used as a compression spring between the cover and the upper ball cup. The maximum permissible play between confronting surfaces of these two parts is in the neighborhood of only 0.4 mm. This gap is necessary so that the steering system can give somewhat in response to sudden shocks. The metal-to-metal contact between the upper ball cup and the cover therefore produces a clicking which is very annoying.
OBJECT OF THE INVENTION
It is hence an object of the invention to provide a ball joint of the type described above wherein in a simple manner noise generation in use is suppressed.
SUMMARY OF THE INVENTION
The invention attains this object first and mainly in that the upper ball cup is itself formed as a compression spring in the form of a plate spring and bears constantly directly on the cover and on the ball.
Since the compression spring is always in direct contact with the cover and with the ball, service-related forces only deform the compression spring and do not actually bring together elements that were formerly spaced apart. A substantial further advantage is in the simplified construction and the elimination of a part, since the upper ball cup is itself formed as the compression spring so that the conical coil compression spring of the prior art is eliminated. The above-mentioned object of the invention is attained not by providing an additional part but by eliminating a part.
Whereas in the prior art the ball cups are held in place by the force of the coil spring, according to the invention the upper ball cup is clamped on its outer rim by means of the housing with the cover. Such an arrangement can be compared with a cantilever-mounted but disk-shaped leaf spring.
It is advantageous when the upper ball cup is formed of segments, that is, when the upper ball cup has slits extending radially from its center to near to its continuous edge. Because of the segmenting the deformation of the spring-washerlike ball cup or of its segments can take place without internal stressing.
The upper ball cup is prestressedly deformed like a bell between the cover and the ball.
A further particularly advantageous feature of the invention is that the segments of the upper ball cup have or form bendable sections which tangent the ball along a generally frustoconical surface and whose outside surfaces face an also frustoconical support surface of the cover whose cone angle is somewhat larger than the cone angle of the bendable sections and preferably the arrangement is set up such that the support surface turned toward the cover is somewhat convex relative to the bendable sections of the upper ball cup so that with increasing loading the contact point of the upper ball cup or its segments moves inward on the cover for stressing. This produces a force-related progressive spring restoring force that increases as a result of the increasingly shorter lever arm of the spring, growing with the force applied to the spring. This means that the travel for the spring can be kept small.
BRIEF DESCRIPTION OF THE DRAWING
In addition the invention is best understood with reference to particularly embodiments referring to the drawing. In the drawing
REFERENCES:
patent: 3560035 (1968-01-01), Kindel
patent: 3945739 (1976-03-01), Abe
patent: 4720205 (1988-01-01), Ito
Dubno Herbert
Johnson Blair
Lev Bruce A.
P. C. Turck GmbH & Co. KG
Wilford Andrew
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