Tappet roller retaining approach

Patent metadata

Field	Value
Publication number	US-2018266374-A1
Application number	US-201415539618-A
Country	US
Kind code	A1
Filing date	Dec 23, 2014
Priority date	Dec 23, 2014
Publication date	Sep 20, 2018
Grant date	—

Abstract

A roller assembly, comprising a roller shoe having a bottom surface, and a groove at the bottom surface, the groove having a semicircular portion and a straight portion extending from the semicircular portion, the semicircular portion having a first diameter and the straight portion having a first width, and a cylindrical roller positioned in the roller shoe groove, the cylindrical roller having a second diameter, wherein the first width is greater than or equal to the first diameter and the second diameter is less than the first width.

First claim

1 . A roller assembly, comprising:
a roller shoe having a bottom surface, and a groove at the bottom surface, the groove having a semicircular portion and a straight portion extending from the semicircular portion, the semicircular portion having a first diameter and the straight portion having a first width; and a cylindrical roller positioned in the roller shoe groove, the cylindrical roller having a second diameter; wherein the first width is greater than or equal to the first diameter and the second diameter is less than the first width.

2 . The roller assembly of claim 1 , wherein the roller shoe further includes a first portion at a distal end, a second portion at a proximal end, and an annulus undercut extending from the first portion to the second portion.

3 . The roller assembly of claim 2 , wherein the groove extends through the first portion and the annulus undercut.

4 . The roller assembly of claim 3 , wherein a center of the semicircular portion is located nearer to the proximal end than the first portion.

5 . The roller assembly of claim 1 , further including a tappet body having a distal end and an inner bore, the roller shoe being press-fit into the distal end of the tappet body.

6 . The roller assembly of claim 5 , wherein the inner bore has a third diameter that is smaller than an outer diameter of the first portion and an outer diameter of the second portion, and one of smaller than and equal to an outer diameter of the annulus undercut.

7 . A method, comprising:
inserting a cylindrical roller in a roller shoe; positioning the cylindrical roller into a tappet body; generating a radial force at an interface between a first portion of the cylindrical roller and an inner bore of the tappet body in response to positioning the cylindrical roller into a tappet body; deforming a groove in the cylindrical roller in response to the radial force generated at the interface between the first portion of the cylindrical roller and the inner bore of the tappet body; retaining the roller shoe in the cylindrical roller in response to deforming the groove; and retaining the roller shoe in a fully inserted position with the cylindrical roller protruding.

8 . The method of claim 8 , wherein deforming is controlled at the interface between a first portion of the cylindrical roller and the inner bore of the tappet body.

9 . An article of manufacture, comprising:
a roller shoe having a bottom surface, and a groove formed in the bottom surface, the groove having a semicircular portion located at a center of the groove and a straight portion extending from the semicircular portion, the semicircular portion having a first diameter and the straight portion having a first width; and a cylindrical roller positioned in the roller shoe, the cylindrical roller having a second diameter; wherein the first width is greater than or equal to the first diameter and the second diameter is less than the first width.

10 . The article of manufacture of claim 9 , wherein the roller shoe further includes a first portion at a distal end, a second portion at a proximal end, and an annulus undercut extending from the first portion to the second portion.

11 . The article of manufacture of claim 10 , wherein the groove extends through the first portion and the annulus undercut.

12 . The article of manufacture of claim 11 , wherein a center of the semicircular portion is located nearer to the proximal end than the first portion.

13 . The article of manufacture of claim 9 , further including a tappet body having a distal end, a proximal end, and an inner bore, the roller shoe being press-fit into the distal end of the tappet body.

14 . The article of manufacture of claim 13 , wherein the inner bore has a third diameter that is smaller than an outer diameter of the first portion and an outer diameter of the second portion, and one of smaller than and equal to an outer diameter of the annulus undercut.

15 . A high pressure fuel pump system, comprising:
a pump housing having a bore; a plunger slidably disposed in the bore; a cam; a tappet body; and a roller assembly disposed in the tappet body between the plunger and the cam; wherein the roller assembly includes a roller shoe having a bottom surface, and a groove at the bottom surface, the groove having a semicircular portion and a straight portion extending from the semicircular portion, the semicircular portion having a first diameter and the straight portion having a first width, and a cylindrical roller slidably disposed in the roller shoe groove, the cylindrical roller having a second diameter, wherein the first width is greater than or equal to the first diameter and the second diameter is less than the first width.

16 . The high pressure fuel pump of claim 15 , wherein the roller assembly is configured to convert rotational movement of the cam into reciprocal movement of the plunger.

Assignees

• Cummins Inc

Inventors

• Wang Chin-Pei
• State Matthew B
• Benham Eric A
• Wenger Justin Gregory
• Lesin Alexander E
• Brewer Kyle J

Classifications

• F04B9/042

  the means being cams · CPC title

• F02M2200/8061

  involving press-fit, i.e. interference or friction fit · CPC title

• F02M59/44

  Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; {Pumps having transducers, e.g. to measure displacement of pump rack or piston} · CPC title

• F02M59/102 Primary

  Mechanical drive, e.g. tappets or cams (F02M45/063 takes precedence) · CPC title

• F04B9/04

  the means being cams, eccentrics or pin-and-slot mechanisms · CPC title