Anti-Rotation Feature for an Engine Tappet

Abstract

An alignment feature for preventing in-bore rotation of an engine tappet. A first portion extends outwards from a tappet and a second portion extends into a hole in the tappet. The first portion extends longitudinally past the mounting hole such that when the feature and tappet are installed in an engine bore, the entire feature is prevented from rotation within the hole. The second portion extending orthogonally from the first portion into the mounting hole need not be close-fitting to the hole. The first portion may be substantially semi-cylindrical, having a convex cylindrical outer surface for fitting the walls of a semi-cylindrical channel in the engine bore and a concave cylindrical inner surface for fitting the outer wall of the tappet. The pin portion is preferably cylindrical. Other pin shapes are possible. The alignment feature may or may not be hardened.

1 . An alignment feature for preventing rotation of an engine tappet in a bore of an internal combustion engine, comprising:
 a) a first portion extending outwards from said tappet for riding in a channel in said engine longitudinal of said bore; and   b) a second portion extending into a mounting hole formed in said tappet,   wherein said first portion extends longitudinally past said mounting hole such that when said alignment feature and said tappet are installed in said bore and said channel, said alignment feature is prevented from rotation within said mounting hole and said tappet is prevented from rotation within said bore.   
   
   
       2 . An alignment feature in accordance with  claim 1  wherein said channel is cylindrical, and wherein an outer surface of said first portion is cylindrically convex to fit said channel. 
   
   
       3 . An alignment feature in accordance with  claim 2  wherein an inner surface of said first portion is cylindrically concave to fit an outer surface of said tappet. 
   
   
       4 . An alignment feature in accordance with  claim 1  wherein said mounting bore and said second portion are cylindrical. 
   
   
       5 . An alignment feature in accordance with  claim 1  wherein said tappet is selected from the group consisting of hydraulic valve lifter, deactivation hydraulic valve lifter, and fuel pump lifter. 
   
   
       6 . An alignment feature in accordance with  claim 1  wherein said mounting bore extends through a wall of said tappet into a chamber therein. 
   
   
       7 . An alignment feature in accordance with  claim 6  wherein said second portion extends into said chamber. 
   
   
       8 . An alignment feature in accordance with  claim 7  wherein said second portion is captured in said second chamber. 
   
   
       9 . An alignment feature in accordance with  claim 8  wherein a method for said capture is selected from the group consisting of spot welding and peening of said second portion to said tappet. 
   
   
       10 . An alignment feature in accordance with  claim 1  wherein at least said first portion is hardened above a Rockwell C hardness of about 25. 
   
   
       11 . An alignment feature in accordance with  claim 1  wherein said alignment feature in its entirety is hardened above a Rockwell C hardness of about 25. 
   
   
       12 . An alignment feature in accordance with  claim 11  wherein said second portion is captured in said second chamber by peening to define an interference fit between said second portion and said mounting hole. 
   
   
       13 . An internal combustion engine comprising an alignment feature for preventing rotation of an engine tappet in an engine bore, said alignment feature including,
 a first portion extending outwards from said tappet for riding in a channel in said engine longitudinal of said bore, and   a second portion extending into a mounting hole formed in said tappet,   wherein said first portion extends longitudinally past said mounting hole such that when said alignment feature and said tappet are installed in said bore and said channel, said alignment feature is prevented from rotation within said mounting hole and said tappet is prevented from rotation within said bore.