Claims:We Claim

1. An oldham couple (10), said oldham couple (10) comprising:
a first side (12) comprising a first surface, said first side (12) secured to a drive shaft (14) of a high pressure fuel pump (16);
an opposite second side (18) comprising a second surface, said opposite second side (18) secured to a driving shaft (20) of a prime mover (22); characterized in that
a coating of polytetrafluoroethylene applied on said first side (12) comprising the first surface, and said opposite second side (18) comprising the second surface such that the coating of polytetrafluoroethylene acts as a protective layer and protects said oldham couple (10) against wear caused due to abrasion between said oldham couple (10) and said drive shaft (14) of said high pressure fuel pump (16) and between said oldham couple (10) and said driving shaft (20) of said prime mover (22).

2. The oldham couple (10) in accordance with Claim 1 wherein the coating of polytetrafluoroethylene applied on said first side (12) comprising the first surface, and said opposite second side (18) comprising the second surface such that the coating of polytetrafluoroethylene acts as a damper and dampens the vibrations between said oldham couple (10) and said driving shaft (20) of said prime mover (22) thereby mitigating the level of vibrations that are transmitted to said drive shaft (14) of said high pressure fuel pump (16).

3. The oldham couple (10) in accordance with Claim 1 wherein the coating of polytetrafluoroethylene applied on said first side (12) comprising the first surface, and said opposite second side (18) comprising the second surface such that the coating of polytetrafluoroethylene does not require the geometrical tolerances, surface finish, and clearance between said oldham couple (10) and said driving shaft (20) of said prime mover (22) and said oldham couple (10) and said drive shaft (14) of said high pressure fuel pump (16) to be well defined.

4. The oldham couple (10) in accordance with Claim 1 wherein said prime mover (22) may be one of a crank shaft of an engine, a cam shaft of the engine, and a power generating source such as but not limited to a generator.
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to an oldham couple that is secured between a drive shaft of an engine and a drive shaft of a high pressure fuel pump, and more specifically to a polytetrafluoroethylene coating that is applied on the oldham couple secured between the drive shaft of the engine and the drive shaft of the high pressure fuel pump.

Background of the invention
[0002] JP 2000230632 A describes a one way couple incorporated pulley device. To increase tension of an endless belt stretched on a pulley, to ensure a rolling fatigue life of support bearings even when a radial load applied to the pulley is large, and to improve durability by reducing frictional force acting on a rubbing part and preventing abrasion at the time of relative rotation of the pulley and a sleeve. Roller bearings having a large load capacity are used as support bearings. By opposing inner ring side flange parts to outer ring flange parts respectively, rubbing between a pulley and a sleeve in a thrust direction is prevented. Further, a coating of polytetrafluoroethylene resin is formed on a surface in which the inner ring side flange parts and the outer ring flange parts are faced to each other.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of an oldham couple that is secured between a drive shaft of an engine and a drive shaft of a high pressure fuel pump.

Detailed description of the embodiments
[0004] Figure 1 illustrates a schematic diagram of an oldham couple 10. The oldham couple 10 comprises a first side 12 comprising a first surface, the first side 12 secured to a drive shaft 14 of a high pressure fuel pump 16, and an opposite second side 18 comprising a second surface, the opposite second side 18 secured to a driving shaft 20 of a prime mover 22. A coating of polytetrafluoroethylene is applied on the first side 12 comprising the first surface, and the opposite second side 18 comprising the second surface such that the coating of polytetrafluoroethylene acts as a protective layer and protects the oldham couple 10 against wear caused due to abrasion between the oldham couple 10 and the drive shaft 14 of the high pressure fuel pump 16, and between the oldham couple 10 and the driving shaft 20 of the prime mover 22.

[0005] The oldham couple 10 comprises a first side 12 that comprises a first surface. The first side 12 of the oldham couple 10 is secured to a drive shaft 14 of a high pressure fuel pump 16 and drives the high pressure fuel pump 16. More specifically, the drive shaft 14 of the high pressure fuel pump 16 is inserted within the bore that is defined on the oldham couple 10 and secured thereto via a transition fit. An opposite second side of the oldham couple 10 comprises a second surface. In the exemplary embodiment, an outer periphery 24 of the oldham couple 10 is secured to a driving shaft 20 of a prime mover 22 that drives the oldham couple 10 thereto. In an exemplary embodiment, the prime mover 22 may be an engine shaft that is secured to the engine. In an alternate exemplary embodiment, the prime mover 22 may be a cam shaft of the engine that is adapted to open the inlet and the outlet valves of the engine. In yet another alternate exemplary embodiment, the prime mover 22 may be any driving shaft from a driving source that is secured to the oldham couple 10, and correspondingly drives the oldham couple 10.

[0006] In an exemplary embodiment, a coating of polytetrafluoroethylene is applied on the first side 12 comprising the first surface of the oldham couple 10. Moreover, a coating of polytetrafluoroethylene is applied on the opposite second side 18 comprising the second surface of the oldham couple 10. Therein, the oldham couple 10 is secured between the driving shaft 20 of the prime mover 22 that drives the oldham couple 10 and the drive shaft 14 of the high pressure fuel pump 16. The coating of polytetrafluoroethylene that is applied on the first side 12 comprising the first surface of the oldham couple 10 and the opposite second side 18 comprising the second surface of the oldham couple 10 acts as a protective layer. More specifically, the coating of polytetrafluoroethylene that is applied on the oldham couple 10 acts as a protective layer, and protects the oldham couple 10 against wear caused due to abrasion between the oldham couple 10 and the drive shaft 14 of the high pressure fuel pump 16, as well as between the oldham couple 10 and the driving shaft 20 of the prime mover 22.

[0007] The coating of polytetrafluoroethylene that is applied on the first side 12 and the opposite second side 18 of the oldham couple 10 acts as a damper and dampens the vibrations between the oldham couple 10 and the driving shaft 20 of the prime mover 22. As the vibrations between the oldham couple 10 and the driving shaft 20 of the prime mover 22 are damped by the coating of polytetrafluoroethylene, the level of vibrations that are transmitted by the oldham couple 10 to the drive shaft 14 of the high pressure fuel pump 16 are mitigated.

[0008] In addition, the coating of polytetrafluoroethylene is applied on the first side 12, and the opposite second side 18 of the oldham couple 10 such that the coating of polytetrafluoroethylene does not require the geometrical tolerances, surface finish, and clearance between the oldham couple 10 and the driving shaft 20 of the prime mover 22 as well as the oldham couple 10 and the drive shaft 14 of the high pressure fuel pump 16 to be well defined. This is because, the lubricating properties of the polytetrafluoroethylene cause the driving shaft 20 of the prime mover 22, the drive shaft 14 of the high pressure fuel pump 16, and the oldham couple 10 to synchronize with each other with reduced friction. Therefore, the coating of polytetrafluoroethylene that is applied on the first side 12 and the opposite second side 18 of the oldham couple 10 serves many useful applications as outlined above.

[0009] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.