Valve timing adjuster

Abstract

A valve timing adjuster includes a housing and a vane rotor. A hub portion of the vane rotor includes an advance passage and a retard passage. One of a shoe of the housing and the hub portion includes an advance groove and a retard groove. The advance groove provides communication between an advance chamber and the advance passage at a full retard position. The retard groove provides communication between a retard chamber and the retard passage at a full advance position. The advance groove and the retard groove are spaced apart from each other along a longitudinal axis of the housing.

1 . A valve timing adjuster for adjusting timing of opening and closing at least one of an intake valve and an exhaust valve by changing a phase between a drive shaft of an internal combustion engine and a driven shaft, which opens and closes the at least one of the intake valve and the exhaust valve based on a driving force of the drive shaft, the valve timing adjuster comprising:
 a housing that is rotatable synchronously with one of the drive shaft and the driven shaft, wherein the housing having:
 a tubular peripheral wall; 
 a shoe that radially inwardly projects from the peripheral wall; 
 a front plate that is provided on one side of the peripheral wall along a longitudinal axis of the housing; and 
 a rear plate that is provided on the other side of the peripheral wall along the longitudinal axis; and 
   a vane rotor that is rotatable synchronously with the other one of the drive shaft and the driven shaft, wherein:   the vane rotor includes:
 a hub portion that is provided coaxially with the housing, wherein the hub portion slidably contacts a slidably contacting surface of the shoe located on a radially inner side thereof, wherein the hub portion has a generally hollow cylindrical shape, wherein the peripheral wall, the shoe, and the hub portion defines therebetween a pressure chamber; and 
 a vane that radially outwardly projects from the hub portion to divide the pressure chamber into an advance chamber and a retard chamber that are arranged in a circumferential direction of the housing; 
   the vane rotor rotates relative to the housing based on pressure of working fluid that is supplied to one of the advance chamber and the retard chamber;   the hub portion includes:
 an advance passage that has an opening, which faces an advance side of the slidably contacting surface adjacent the advance chamber when the vane rotor is located at a full retard position relative to the housing; and 
 a retard passage that has an opening, which faces a retard side of the slidably contacting surface adjacent the retard chamber when the vane rotor is located at a full advance position relative to the housing; 
   one of the shoe and the hub portion includes:
 an advance groove that provides communication between the advance chamber and the opening of the advance passage when the vane rotor is located at the full retard position relative to the housing; and 
 a retard groove that provides communication between the retard chamber and the opening of the retard passage when the vane rotor is located at the full advance position relative to the housing; and 
   the advance groove and the retard groove are spaced apart from each other along the longitudinal axis of the housing.   
     
     
         2 . The valve timing adjuster according to  claim 1 , wherein:
 the one of the shoe and the hub portion is the shoe;   the advance groove and the retard groove are formed on the slidably contacting surface of the shoe;   one of the advance groove and the retard groove is provided on a side of the slidably contacting surface adjacent the rear plate; and   the other one of the advance groove and the retard groove is provided on the other side of the slidably contacting surface adjacent the front plate.   
     
     
         3 . The valve timing adjuster according to  claim 2 , wherein:
 the advance groove and the retard groove extend in the circumferential direction without extending along the longitudinal axis.   
     
     
         4 . The valve timing adjuster according to  claim 1 , wherein:
 the one of the shoe and the hub portion is the hub portion;   the advance groove and the retard groove are formed on an outer wall of the hub portion;   one of the advance groove and the retard groove is provided on a side of the outer wall of the hub portion adjacent the rear plate; and   the other one of the advance groove and the retard groove is provided on the other side of the outer wall of the hub portion adjacent the front plate.   
     
     
         5 . The valve timing adjuster according to  claim 4 , wherein:
 the advance groove and the retard groove extend in the circumferential direction without extending along the longitudinal axis.