Bearing arrangement

Details Bearing arrangement Bearing arrangement

1999-10-20

2001-12-04

Wolfe, Willis R. (Department: 3747)

Internal-combustion engines

Multiple cylinder

Cylinders having opposing heads

C123S056200, C123S056900, C384S049000

Reexamination Certificate

active

06325027

ABSTRACT:

This invention relates to a bearing arrangement. More particularly, this invention relates to a bearing arrangement for a piston rod in an internal combustion engine.
Heretofore, various types of bearing arrangements have been known for transferring forces, between two or more relatively movable components. For example, as described in pending patent application Ser. No. 09/319,035, motion between a reciprocating piston rod and a rotating annular cam guide device is transferred by the use of a ball bearing mounted on the end of the piston rod and rolling relative to a track on the rotating guide device.
Typically, a ball bearing is constructed with balls or rollers of solid construction which are able to roll between the inner and outer races of a radial bearing or between two annular rings of a thrust bearing or between two tracks or a linear bearing. In general, and especially in extreme cases, each bearing ball or roller is supported solely through a point or a rather restricted support area due to the high rigidity of the bearing ball or roller combined with a correspondingly high rigidity of the bearing race or support track.
During the transfer of a high pressure load and/or with rapid reciprocating movements of the bearing ball, a significant wear and tear occurs on the bearing ball or roller. In addition, the support surfaces are also subjected to a high wear and tear. Consequently, over a period of time, either the bearing ball/roller or the bearing race/ring or both are gradually worn down or deformed with a result that the bearing has a reduced life.
Typically, wear and tear is due mainly to a rapid repeated high local load imposed upon the bearing ball combined with a restricted load transfer area between the bearing ball and the support surface.
Additional problems are also caused by extreme loads combined with extreme bearing ball velocities and extreme gravity forces provided by the solid and compact bearing ball. This is particularly present in ball bearings which are moved in reciprocating movements in high speed engines.
In practical use, for example, when exposed to regularly occurring extreme pressure loads combined with extreme velocities, each bearing ball as well as the associated support surface is vulnerable and has accordingly been manufactured of a solid, rather shape-stable and non-elastic material. Accordingly, the bearing ball, raceway and ring or similar support surface has been made of a material such as steel, other suitable metal or similar solid material which is resistant to high loads and wear and tear. However, such solid and rather non-elastic materials cause wear and tear especially of the support track and the associated holder.
In a specific employment, for example, when employing a ball bearing to transfer loads to a reciprocating piston rod moving at extreme velocities, i.e. at high speed, the reciprocating movements in a longitudinal direction of the piston rod combined with high speed rolling/revolving movements of the bearing balls, produces gravitational forces in the balls which rise to corresponding extreme values. This also imparts extreme loads on and extensive wear and tear of the associated support surface.
Accordingly, it is an object of the invention to reduce the wear and tear of a bearing arrangement.
It is another object of the invention to utilize low weight spheres in a ball bearing arrangement.
It is another object of the invention to reduce gravity forces and extreme loading in a bearing arrangement without reducing the durability of the bearing arrangement.
It is another object of the invention to provide for an enlarged support area between a pressure sphere and an opposed support surface of a bearing arrangement in order to transfer a load over an enlarged support area.
It is another object of the invention to provide for a locally restricted elastic deformation of a bearing member in a bearing arrangement for a reciprocating piston rod of an engine.
Briefly, the invention provides a bearing arrangement comprising a track, a hollow-shaped sphere mounted on the track for relative movement thereto and a holder opposite the track and having the sphere rotatably held therein. In one embodiment, the holder is disposed on a fixed axis while the track is movable relative to the holder. For example, the track may be of annular shape and may be rotatable about an axis parallel to the fixed axis of the holder. In another embodiment, the track may be stationary while the holder is movable along the track. In either embodiment, the track is provided with a groove for receiving the sphere.
In accordance with the invention, the bearing sphere is elastically deformable under a compressive force which is applied between the track and the holder.
In an embodiment which employs a rotatable annular flange having an annular groove to receive the hollow-shell shaped sphere, the annular flange may be part of a cam guide device for driving a piston rod in a reciprocating manner in a cylinder of an internal combustion engine. In addition, the groove in the annular flange may have a curved contour to effect reciprocation of the piston as the flange rotates.
One new result of employing the bearing arrangement is that the pressure load on the pressure sphere, in general, is considerably reduced. This is due to a considerable reduction of the sphere mass and, accordingly, the sphere weight and its occurring gravitational forces. This result is especially of particular importance in cases where high or extreme velocities are involved, e.g. in connection with use of the bearing arrangement with a reciprocating piston rod which is exposed to high speed reciprocating movement velocities combined with high sphere rolling velocity. In the latter case, a considerable reduction of gravitational forces acting on the sphere is achieved, due to a corresponding reduction of its mass and weight. The total pressure sphere load is accordingly considerably reduced.
The hollow shell-shaped pressure sphere is provided with a relatively thin wall thickness which enables an elastic deformation of at least a local sphere surface portion supported against the sphere holder and/or the sphere track. The use of a thin walled shell-shaped pressure sphere allows an intentional local elastic deformation of the pressure sphere without reducing the total strength of the pressure sphere.
The resulting enlarged support area between the pressure sphere and its support surface causes a reduced pressure to act between the pressure sphere and its opposed support surface and results in reduced local wear and tear.
In a specific employment, when employed at the outer end of an axially reciprocating piston rod acting against a guide cam in a piston-cylinder arrangement, such as described in the parent application, the bearing arrangement is advantageous in that a pair of pressure spheres are located at opposite sides of an intermediate annular support flange and the flange is provided with a groove or track at opposite sides for individual support of either pressure sphere. The result is that the pressure load involved in two opposite axial directions in the piston rod may be transferred in a controlled and secure manner centrally thereof, as the case may be, through either of the opposed pressure spheres at opposite sides of the intermediate annular support flange, i.e. in mutually opposite directions.
In normal operation, a first one of the pressure spheres is in direct contact with its support track, whereas the second one may be out of support track contact and without pressure load. This effect may be caused by employment of elastically deformable pressure spheres. As soon as it is required, i.e. when a load occurs in an opposed direction, the latter load can momentarily be transferred through the second pressure sphere while allowing an unloading effect on the first pressure sphere.
This effect is of special importance in cases where each of the sphere tracks is contoured as a sine-like curve. This means that one of the pressure spheres is maintained out of contact with

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