Valve timing regulator

Abstract

A valve timing adjusting apparatus includes: recesses provided opposite to the wall surfaces in a circumferential direction of a shoe and a vane in an advance hydraulic chamber; a holding member insertion-disposed into the recesses from an axial direction; and an assist spring disposed between the holding member on the shoe side and the holding member on the vane side to urge a rotor in an advance direction, and further a clearance formed by a length in the axial direction of the holding member provided on the vane side and a length in the axial direction of the case is set to not less than a sum of an increment of the length in the axial direction in consideration of a tilt of the holding member produced by a gap between the holding member and recess, and an increment due to the thermal expansion.

1 . A valve timing adjusting apparatus having: a camshaft that drive a valve of an internal combustion engine to open and close; a case that has a plurality of shoes on an inner peripheral surface thereof, is rotatably provided on the camshaft, and is rotationally driven by an output of the internal combustion engine, and; a rotor that has a plurality of vanes provided on an outer peripheral surface thereof, each forming a retard hydraulic chamber and an advance hydraulic chamber between the vane and two side-wall surfaces in a circumferential direction of the corresponding shoe, is relatively rotatably housed in the case, and is coupled to the camshaft, comprising:
 recesses provided opposite to the wall surfaces in the circumferential direction of the shoe and the vane in the advance hydraulic chamber;   a holding member insertion-disposed into each of the recesses from an axial direction of the rotor; and   an assist spring disposed between the holding member on the shoe side and the holding member on the vane side to urge the rotor in an advance direction,   wherein a clearance formed by a length in the axial direction of the rotor of the holding member provided on the vane side and a length in the axial direction of the rotor of the case is set to be equal to or greater than a sum of an increment of the length in the axial direction of the rotor in consideration of a tilt of the holding member produced by a gap between the holding member and the recess, and an increment due to thermal expansion thereof.   
     
     
         2 . The valve timing adjusting apparatus according to  claim 1 , wherein a falling-out prevention portion for narrowing an opening is provided on the recess provided on the wall surface in the circumferential direction of the vane, and a first tapered portion that comes into contact with the falling-out prevention portion is formed on the holding member. 
     
     
         3 . The valve timing adjusting apparatus according to  claim 1 , wherein a width in the axial direction of the assist spring of a second tapered portion provided on the holding member is set to be greater than a wire-to-wire distance of the assist spring when the assist spring is set in the most advanced position. 
     
     
         4 . The valve timing adjusting apparatus according to  claim 1 , wherein the bottom surfaces of the holding members on the shoe side and on the vane side are parallel to each other in the most advanced position where a set length of the assist spring is at a maximum.