Rocker arm assembly

Abstract

A rocker arm assembly for a valve operation in an engine includes a rocker main body extending between a first end and a second end. The first end of the rocker arm main body is configured to receive a valve actuation button and the second end of the rocker arm main body is configured to receive a cam roller assembly. The cam roller assembly includes a cam roller and a bushing is disposed in the cam roller forming a bearing surface. Further, the cam roller assembly includes a bearing component which is disposed in the bushing forming a bearing surface. The bearing component includes an oil hole with an oil delivery pocket which is curved to form a rounded edge and an transitional opening is formed extending from the rounded edge.

What is claimed is: 
     
         1 . A rocker arm assembly comprising:
 a rocker arm main body extending between a first end and a second end;   a valve actuation button disposed at the first end of the rocker arm main body; and   a cam roller assembly disposed at the second end of the rocker arm main body, the cam roller assembly comprising:
 a cam roller with an outer surface and an inner surface; 
 a bushing inserted into the cam roller and provides a bearing surface; 
 a bearing component slip fitted inside the bushing, the bearing component has an outer surface and an inner surface; 
 an oil hole provided on the bearing component wherein an oil delivery pocket of the oil hole at an outer surface of the bearing component has a rounded edge; and 
 a transitional opening extending from the rounded edge. 
   
     
     
         2 . The rocker arm assembly of  claim 1 , wherein the bushing is press fitted inside the cam roller. 
     
     
         3 . The rocker arm assembly of  claim 1  further comprises a clearance provided between the bearing surface and the outer surface of the bearing component. 
     
     
         4 . The rocker arm assembly of  claim 3 , wherein the clearance formed between the bearing surface and the outer surface of the bearing component is configured to receive lubricating oil via the oil hole. 
     
     
         5 . The rocker arm assembly of  claim 1 , wherein an array of equidistant oil holes is provided on the bearing component. 
     
     
         6 . The rocker arm assembly of  claim 1 , wherein the cam roller is made from hardened steel. 
     
     
         7 . The rocker arm assembly of  claim 1 , wherein the bushing is made from cast bronze. 
     
     
         8 . The rocker arm assembly of  claim 7 , wherein the bushing is coated with tin and lead. 
     
     
         9 . An internal combustion engine comprising:
 a cylinder having a piston disposed for reciprocation therein;   a set of valves through which combustion air enters the cylinders is mixed with fuel for combustion therein and through which products of combustion exit the cylinder;   a rocker arm assembly, configured to open and close the set of valves and comprising:
 a rocker arm main body extending between a first end and a second end; 
 a valve actuation button disposed at the first end of the rocker arm main body; and 
 a cam roller assembly disposed at the second end of the rocker arm main body, the cam roller assembly comprising:
 a cam roller with an outer surface and an inner surface; 
 a bushing disposed in the cam roller forming a bearing surface therein; 
 a bearing component with an outer surface and an inner surface wherein the outer surface of the bearing component is in contact with the bushing forming a bearing surface; 
 an oil hole provided in the bearing component wherein an oil delivery pocket of the oil hole at an outer surface of the bearing component is having a rounded edge; and 
 an transitional opening extends from the rounded edge at an interface between the inner surface of the bushing and the outer surface of the bearing component; and 
 
   a camshaft rotatably operatively coupled to the cam roller.   
     
     
         10 . The internal combustion engine of  claim 9 , wherein the bushing is press fitted inside the cam roller. 
     
     
         11 . The internal combustion engine of  claim 9  further comprises a clearance provided between the bearing surface and the outer surface of the bearing component. 
     
     
         12 . The internal combustion engine of  claim 11 , wherein the clearance formed between the bearing surface and the outer surface of the bearing component is configured to receive lubricating oil via the oil hole. 
     
     
         13 . The internal combustion engine of  claim 9 , wherein an array of equidistant oil holes is provided on the bearing component. 
     
     
         14 . The internal combustion engine of  claim 9 , wherein the cam roller is made from hardened steel. 
     
     
         15 . The internal combustion engine of  claim 9 , wherein the bushing is made from cast bronze. 
     
     
         16 . The internal combustion engine of  claim 15 , wherein the bushing is coated with tin and lead. 
     
     
         17 . A method for manufacturing an oil hole in a bearing component of a cam roller assembly, the method comprising:
 forming an oil hole having a countersunk oil delivery pocket on an outer surface of the bearing component;   insertion of an anvil into the bearing component;   advancing a punch having a hardened spherical ball towards the oil hole;   transforming an edge of the countersunk oil delivery pocket of the oil hole to a rounded edge; and   creating a concave transitional opening extending from the rounded edge.