Tappet roller bearing

Abstract

A tappet roller bearing 10 includes a support shaft 20 to be supported on a locker arm 4, and first and second rollers 11 and 12 which can be respectively supported rotatably on the periphery of the support shaft 20 and are arranged together in the axial direction of the support shaft 20. The first roller 11 constitutes a plain bearing, and the second roller 12 constitutes a full type roller bearing or a plain bearing. Due to this, the tappet roller bearing 10 can extend its life, can enhance its assembling efficiency and can reduce its manufacturing cost.

1 . A tappet roller bearing, comprising:
 a support shaft to be fixed to a locker arm for receiving the movement of a cam to be supported on the cam shaft of an engine; and   first and second rollers respectively supported rotatably on the periphery of the support shaft and arranged in the axial direction of the support shaft, wherein:   the first roller constitutes a plain bearing; and   the second roller constitutes a full type roller bearing or a plain bearing.   
     
     
         2 . The tappet roller bearing according to  claim 1 , wherein:
 the cam includes a high speed cam and a low speed cam respectively disposed on the cam shaft slidably in the axial direction of the cam shaft;   the first roller constituting the plain bearing is contacted with the high speed cam; and   the second roller constituting the full type roller bearing is contacted with the low speed cam.   
     
     
         3 . The tappet roller bearing according to  claim 1 , wherein:
 the cam includes a high speed cam and a low speed cam respectively disposed on the cam shaft slidably in the axial direction of the cam shaft;   the outer peripheral surface of the first roller to be contacted with the high speed cam is formed by barrel working to be carried out after polish finishing; and   the outer peripheral surface of the second roller to be contacted with the low speed cam is formed by polish finishing without being barrel worked.   
     
     
         4 . The tappet roller bearing according to  claim 1 , wherein
 the outer peripheral surfaces of the first and second rollers are not crowning worked but have a uniform diameter in the axial direction thereof.   
     
     
         5 . The tappet roller bearing according  claim 1 , wherein
 at least one of the first and second rollers is structured so that an axial direction end face has a convex shape.   
     
     
         6 . The tappet roller bearing according to  claim 5 , wherein:
 at least one of the first and second rollers, the axial direction end face of which is formed to have the convex shape, constitutes a double roller; and   the inner roller of the double roller is structured so that an axial direction end face has a convex shape.   
     
     
         7 . The tappet roller bearing according to  claim 5 , wherein:
 the second roller constitutes a full type roller bearing; and   the multiple rollers of the roller bearing, together with the second roller, are structured so that respective axial direction end faces have a convex shape.   
     
     
         8 . The tappet roller bearing according to  claim 1 , wherein:
 the support shaft is formed to have a staged shape including first and second shaft portions different from each other in the outside diameter dimension thereof;   the first roller is disposed on the periphery of the first shaft portion; and   the second roller is disposed on the periphery of the second shaft portion.   
     
     
         9 . The tappet roller bearing according to  claim 1 , wherein
 the first and second rollers are different from each other in the axial direction width thereof   
     
     
         10 . The tappet roller bearing according to  claim 1 , wherein
 the first and second rollers are different from each other in the roller diameter thereof   
     
     
         11 . The tappet roller bearing according to  claim 1 , further comprising
 a third roller rotatably supported on the periphery of the support shaft and arranged together with the first and second rollers in the axial direction of the support shaft.   
     
     
         12 . The tappet roller bearing according to  claim 1 , further comprising
 a third roller rotatably supported on the periphery of the support shaft and arranged together with the first and second rollers in the axial direction of the support shaft, wherein   in a case that the second roller constitutes a roller bearing, the third roller is situated on the opposite side to the second roller with respect to the first roller.   
     
     
         13 . The tappet roller bearing according to  claim 11 , wherein the outer peripheral surface of at least one of the first to third rollers is crowning worked.