Oil supply structure for continuously variable valve timing apparatus

Abstract

An oil supply structure for a continuously variable valve timing apparatus wherein a plurality of bimetal blocks change in shape based on oil temperature in an oil supply pipe, whereby, when an oil temperature rises, oil pressure supplied to a variable valve timing apparatus is automatically increased to provide the variable valve timing apparatus with a reliable response over an entire operating range.

1 . An oil supply structure for a continuously variable valve timing apparatus comprising a plurality of bimetal blocks that are disposed at an oil supply pipe between an oil pump and said continuously variable valve timing apparatus, said blocks changing in shape due to increased oil pressure to thereby reduce the cross-sectional area of said oil supply pipe.  
   
   
       2 . The structure as defined in  claim 1 , wherein said bimetal blocks comprise a metal with a smaller thermal expansion coefficient disposed at an inner side of said oil supply pipe and a metal with larger thermal expansion coefficient disposed at an outer side of said oil supply pipe, such that a free end of said bimetal blocks moves toward an inner side of said oil supply pipe in response to higher temperatures among temperature ranges experienced by oil flowing in said oil supply pipe.  
   
   
       3 . The structure as defined in  claim 1 , wherein said bimetal blocks are arranged inside said oil supply pipe in equal intervals around a circumferential direction.  
   
   
       4 . An oil supply structure for a continuously variable valve timing apparatus, comprising: 
 an oil pump;    an oil supply pipe communicating with said oil pump for supplying oil to said apparatus; and    temperature responsive restriction means disposed in said oil supply pipe between the oil pump and said apparatus for increasing oil supply pressure at oil temperatures about a critical range.    
   
   
       5 . The oil supply structure of  claim 4 , wherein said temperature responsive restriction means comprises bimetal block disposed around an inner circumference of said oil supply pipe, an end of said blocks bending inward in response to temperatures above the critical range.