Patent Grant
7014382
This application claims priority to, and incorporates by reference, Brazilian Patent Application No. PI0203693-2 filed by Dana Industrial Ltd., an affiliate of Dana Corporation, on Sep. 3, 2002.
1. Field of the Invention
The invention generally relates to ball and socket joints. The invention is specifically applicable tie rod ends in automotive steering and suspension systems.
2. Description of the Background Art
A typical prior art ball-and-socket joint comprises a case or housing in combination with a single ball integrated into one end of a main body, commonly known as spherical pin. This ball-and-socket joint assembly, correctly mounted, has a first fastening system on the external case, and a second fastening system at the opposite exposed end of the spherical pin assembly. Once the external case is attached to a movable part, and the spherical pin exposed end is attached to a separate part, the joint provides angular rotary movement between the respective parts. These types of joints are commonly used on vehicle steering and suspension systems. Depending on the specific application, the case and spherical pin may have different operational characteristics required to facilitate the specific function of the joint.
In operation, the ball-and-socket joint allows the swiveling movement of the spherical pin, but at the same time, restricts the angular movement of this spherical pin in certain directions, so that the force generated between the external case attachment point and the exposed end attachment point is communicated along the longitudinal axis of the spherical pin, as required in a functional tie rod or steering rod system.
In prior art systems, extreme angies between the spherical pin and the case, and rotational problems with the spherical pin have resulted in premature wear and failure. To address this problem, various solutions have been proposed, including alternative configurations of the case opening, and the replacement of the protective sealing cover of the ball-and-socket joint with a type of rubber bushing that, when compressed, imparts a spring effect to the assembly. However, neither of these techniques, either alone or in combination has resolved the wear problem. Additionally, the replacement protective cover incorporating the rubber bushing requires additional machining, increases production costs, and provides inferior protection relative to the original ball joint cover. If the ball joint cover fails, impurities such as dust, sand, and water can contaminate the joint and rapidly degrade its function until failure occurs. Further, the effective use of the prior art systems is limited to applications with little relative movement, and low stress on the spherical pin.
In order to eliminate these deficiencies, the present self-centering ball-and-socket joint has been developed. The present invention may be used in any system, but is designed primarily for those requiring angular movement restrictions of the spherical pin in certain directions, while retaining a free rotary movement capability. More specifically, the joint was designed for automotive tie rod applications. In operation, the invention functions to ensure that the tie rod will always be aligned with the other components of the system, and the self-centering function of the spherical pin operates to ensure that component forces are aligned with the spherical pin's longitudinal axis.
The invention comprises a self-centering ball-and-socket joint used in connecting parts requiring restricted angular movement in a pre-established direction, and free rotary movement in corresponding directions. The joint is comprised of a spherical pin with an encased end, and an opposite exposed end having a connecting system. The encased end is comprised of two hemispheres, one with a relatively larger diameter, and one with a smaller diameter. The hemispheres are joined, and immediately encased by upper and lower bearings, with an external casing enclosing the entire assembly. The lower bearing applies a spring-type force equal and opposite to angular forces applied to the spherical pin. The interaction between the lower hemispherical end of the spherical pin, and the elastic lower bearing, exerts a continuous force on the spherical pin to return to the spherical pin's previous geometric axis.
The present invention is a relatively simple self-centering ball and socket-type joint, with superior movement and wear characteristics. The ball and socket type joint is primarily designed for motor vehicle applications, specifically, in automotive steering and suspension systems.
An embodiment of the present invention will now be described with reference to the accompanying drawing. It should be noted that the terms “front”, “rear”, “left”, “right”, “upper”, and “lower”, relate to directions as viewed in
As seen in
A sealing cap 6 is attached to the spherical pin 1 at the point where the pin 1 emerges from the external case 4. At its upper end, the sealing cap 6 is fastened to the spherical pin 1 by an upper sealing ring 7. At its lower end, the sealing cap 6 is attached to the upper end of the external case 4 by a lower ring 8.
At the enclosed end of the spherical pin 1, two hemispheres, or half-ball segments 9, 10, are positioned, and joined to form a single part. The hemispheres 9, 10, and spherical pin 1 may be created from a single piece of material to increase the strength of the assembly, or the hemispheres 9, 10, and spherical pin 1 they may be created by joining component parts. The upper hemisphere 9 has a greater diameter than the lower hemisphere 10. The upper hemisphere is coupled to the upper bearing 3, and the lower hemisphere is coupled to the lower bearing 2. The lower bearing 2 is comprised of material having elastic characteristics and properties such that, it not only supports the axial load of the spherical pin, but also, through contact with the smaller diameter hemisphere 10, applies a counteracting force in an equal and opposite direction to lateral forces applied to the spherical pin 1. The net effect of the upper and lower hemispheres 9, 10, and upper and lower bearings 2, 3, on the spherical pin 1, is to create a unique spring effect, that continually urges the spherical pin 1, back toward its previous geometric center. Holes 11 in the base of the lower bearing 2 adjacent to the lower sealing cover 5 also effectively assist the lower bearing 2 in counteracting the lateral forces applied to the spherical pin 1.
The invention, as described, may be modified in multiple ways and applied in various technological applications. For example, in addition to automotive applications, the ball-and-socket joint may be used in nautical and aeronautical applications as well. Similarly, although the materials of construction are generally described, they may also include a variety of compositions consistent with the function of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0203693 | Sep 2002 | BR | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3430995 | Herbenar et al. | Mar 1969 | A |
| 3613201 | Herbenar | Oct 1971 | A |
| 3790195 | Herbenar | Feb 1974 | A |
| 5649779 | Martin et al. | Jul 1997 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20040042847 A1 | Mar 2004 | US |
