Claims:We Claim

1. An oldham coupling assembly (10) of a high pressure fuel pump, said oldham coupling assembly (10) comprising:
a flanged portion (12), said flanged portion (12) having a bore (14) defined therethrough, the bore (14) having a first spherical portion (16) and a second spherical portion (18) defined at its opposing sides, and a third spherical portion (20) and a fourth spherical portion (22) defined at its opposite opposing sides;
a shaft portion (24), a first end of which is secured to an engine, a second end of which is inserted through the bore (14) that is defined in said flanged portion (12) and secured thereto, said shaft portion (24) having a first spherical portion (26) and a second spherical portion (28) defined at its opposing sides that mates with the first spherical portion (16) and the second spherical portion (18) of said flanged portion (12), and a third spherical portion (30) and a fourth spherical portion (32) defined at its opposite opposing sides that mates with the third spherical portion (20) and the fourth spherical portion (22) of said flanged portion (12).

2. The oldham coupling assembly (10) of the high pressure fuel pump in accordance with Claim 1 wherein the bore (14) having the first spherical portion (16) and the second spherical portion (18) defined at its opposing sides is concave in shape, and the third spherical portion (20) and the fourth spherical portion (22) defined at its opposite opposing sides is concave in shape.

3. The oldham coupling assembly (10) of the high pressure fuel pump in accordance with Claim 1 wherein the shaft portion (24) having the first spherical portion (26) and the second spherical portion (28) defined at its opposing sides is convex in shape, and the third spherical portion (30) and the fourth spherical portion (32) defined at its opposite opposing sides is convex in shape.
, 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 a high pressure fuel pump, and more specifically to an oldham coupling assembly of the high pressure fuel pump.

Background of the invention
[0002] DE 102011076021 A1 describes a pump for conveying fluid, particularly fuel, to an accumulator injection system of an internal combustion engine of a motor vehicle. The pump has a housing and a drive shaft that is partially arranged in the housing. A coupling element is coupled with the housing and is mounted relative to the housing in a rotary manner. The coupling element is coupled with the drive shaft for transferring torque from the coupling element to the drive shaft. The coupling element has a retainer for a drive element, particularly for a belt or a chain. The coupling element is coupled with the drive shaft by a claw coupling, particularly an oldham coupling.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates an oldham coupling assembly of a high pressure fuel pump in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates an oldham coupling assembly 10 of a high pressure fuel pump in one embodiment of the invention. The oldham coupling assembly 10 comprises a flanged portion 12, the flanged portion 12 having a bore 14 defined therethrough, the bore 14 having a first spherical portion 16 and a second spherical portion 18 defined at its opposing sides, and a third spherical portion 20 and a fourth spherical portion 22 defined at its opposite opposing sides. The oldham coupling 10 assembly further comprises a shaft portion 24, a first end of which is secured to an engine, a second end of which is inserted through the bore 14 that is defined in the flanged portion 12 and secured thereto, the shaft portion 24 having a first spherical portion 26 and a second spherical portion 28 defined at its opposing sides that mates with the first spherical portion 16 and the second spherical portion 18 of the flanged portion 12, and a third spherical portion 30 and a fourth spherical portion 32 defined at its opposite opposing sides that mates with the third spherical portion 20 and the fourth spherical portion 22 of the flanged portion 12 respectively.

[0005] The oldham coupling assembly 10 of the high pressure fuel pump comprises a flanged portion 12 that has a bore 14 defined therethrough, and a shaft 24 that is secured to the flanged portion 12. The bore 14 that is defined in the flanged portion 12 of the oldham coupling assembly 10 has a first spherical portion 16 and a second spherical portion 18 that are defined at its opposing sides. Moreover, the bore 14 that is defined in the flanged portion 12 of the oldham coupling assembly 10 has a third spherical portion 20 and a fourth spherical portion 22 defined at its opposite opposing sides. Therefore, the third spherical portion 20 and the fourth spherical portion 22 are adjacent to the first spherical portion 16 and the second spherical portion 18 of the oldham coupling assembly 10 respectively.

[0006] A shaft portion 24 is secured to the flanged portion 12 of the oldham coupling assembly 10. More specifically, the shaft portion 24 comprises a first end and an opposite second end. A first end of the shaft portion 24 is secured to a housing of the high pressure fuel pump by means of a fastener. A second end of the shaft portion 24 is inserted through the bore 14 that is defined in the flanged portion 12 and secured thereto by securing the high pressure fuel pump in position. The shaft portion 24 comprises a first spherical portion 26 and a second spherical portion 28 defined at its opposing sides that mates with the first spherical portion 16 and the second spherical portion 18 of the flanged portion 12. In addition, the shaft portion 24 comprises a third spherical portion 30 and a fourth spherical portion 32 defined at its opposite opposing sides that mates with the third spherical portion 20 and the fourth spherical portion 22 of the flanged portion 12. Once the shaft portion 24 is inserted within the flanged portion 12, the shaft portion 24 is held in place by securing the high pressure fuel pump to ensure no axial movement of the shaft portion 24 within the flanged portion 12.

[0007] In the exemplary embodiment, the bore 14 comprises the first spherical portion 16 and the second spherical portion 18 that are defined at its opposing sides and is concave in shape. More specifically, the first spherical portion 16 and the second spherical portion 18 is each concave in shape. In addition, the third spherical portion 20 and the fourth spherical portion 22 are defined at its opposite opposing sides is concave in shape. More specifically, the third spherical portion 20 and the fourth spherical portion 22 is each concave in shape respectively. The third spherical portion 20 and the fourth spherical portion 22 is adjacent to and abuts against the first spherical portion 18 and the second spherical portion 20 respectively.

[0008] In the exemplary embodiment, the shaft portion 24 comprising the first spherical portion 26 and the second spherical portion 28 that are defined at its opposing sides and is convex in shape. More specifically, the first spherical portion 26 and the second spherical portion 28 is each convex in shape. In addition, the third spherical portion 30 and the fourth spherical portion 32 are defined at its opposite opposing sides is convex in shape. More specifically, the third spherical portion 30 and the fourth spherical portion 32 is each convex in shape respectively. The third spherical portion 30 and the fourth spherical portion 32 is adjacent to and abuts against the first spherical portion 26 and the second spherical portion 28 respectively.

[0009] When the first spherical portion 26 and the second spherical portion 28 of the shaft portion 24 abuts against the first spherical portion 16 and the second spherical portion 18 of the flanged portion 12, the first spherical portion 26 and the second spherical portion 28 of the shaft portion 24 is wedged against the first spherical portion 18 and the second spherical portion 20 of the flanged portion 12 respectively. Similarly, when the third spherical portion 30 and the fourth spherical portion 32 of the shaft portion 24 abuts against the third spherical portion 20 and the fourth spherical portion 22 of the flanged portion 12, the third spherical portion 30 and the fourth spherical portion 32 of the shaft portion 24 is wedged against the third spherical portion 20 and the fourth spherical portion 22 of the flanged portion 12 respectively. Due to the greater surface contact between the shaft portion 24 and the flanged portion 12, the stress concentration between the shaft portion 24 and the flanged portion 12 is greatly reduced. Therefore, the wear that occurs on the shaft portion 24 and on the flanged portion 12 is substantially reduced due to the increased surface area of contact between the shaft portion 24 and the flanged portion 12.

[0010] 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.