Valve timing control apparatus

Abstract

A check valve is provided in a fluid passage between a phase change valve and a fluid supply source. The check valve enables a flow of the hydraulic fluid from the fluid supply source to a retarding chamber or an advancing chamber defined in a housing in corporation with a vane rotor received therein. The check valve blocks a flow of the hydraulic fluid from the retarding chamber or the advancing chamber to a fluid supply source side. A filter is provided in the fluid passage between the check valve and the fluid supply source to remove debris from the hydraulic fluid before supplying of the hydraulic fluid to the check valve.

1 . A valve timing control apparatus that adjusts opening and closing timing of at least one of an intake valve and an exhaust valve of an internal combustion engine and is placed in a drive force transmission system, which transmits a drive force from a drive shaft of the internal combustion engine to a driven shaft that drives the at least one of the intake valve and the exhaust valve to open and close the same, the valve timing control apparatus comprising:
 a housing that is rotated together with one of the drive shaft and the driven shaft and has a receiving chamber, which is formed within a predetermined angular range in a rotational direction;   a vane rotor that is rotated together with the other one of the drive shaft and the driven shaft and has a vane, which is received in the receiving chamber to partition the receiving chamber into a retarding chamber and an advancing chamber, wherein the vane rotor is rotated relative to the housing in a retarding direction or an advancing direction through use of a pressure of hydraulic fluid in the retarding chamber and a pressure of hydraulic fluid in the advancing chamber to control a relative phase of the vane rotor relative the housing;   a phase change valve that is changeable between an operational state for supplying hydraulic fluid from a fluid supply source to the retarding chamber and an operational state for discharging the hydraulic fluid from the retarding chamber and is also changeable between an operational state for supplying the hydraulic fluid from the fluid supply source to the advancing chamber and an operational state for discharging the hydraulic fluid from the advancing chamber;   a check valve that is provided in a fluid passage between the phase change valve and the fluid supply source, wherein the check valve enables a flow of the hydraulic fluid from the fluid supply source to the retarding chamber or the advancing chamber and blocks a flow of the hydraulic fluid from the retarding chamber or the advancing chamber to a fluid supply source side; and   a filter that is provided in the fluid passage between the check valve and the fluid supply source to remove debris from the hydraulic fluid before supplying of the hydraulic fluid to the check valve.   
   
   
       2 . The valve timing control apparatus according to  claim 1 , wherein:
 the fluid passage between the phase change valve and the fluid supply source includes a connecting point, which is connected to a branch passage that supplies the hydraulic fluid to a lubricating system of the internal combustion engine; and   the check valve is provided in the fluid passage between the connecting portion and the phase change valve.   
   
   
       3 . The valve timing control apparatus according to  claim 2 , wherein the filter is provided in the fluid passage between the connecting point and the check valve.