Valve opening/closing timing control device

Abstract

A valve opening/closing timing control device includes a driving rotary body rotatable in synchronism with a crankshaft of an internal combustion engine, a driven rotary body rotatable in unison with a cam shaft of the internal combustion engine and rotatable also relative to the driving rotary body within this driving rotary body, a fluid pressure chamber formed by the driving rotary body and the driven rotary body, and a partitioning portion that partitions the fluid pressure chamber into an advance chamber and a retard chamber. The driving rotary body includes an aluminum housing having a pulley that receives a drive force of the crankshaft via a drive belt and a plate attached to at least one face of the housing. Between the housing and the plate, there is provided a gap allowing outflow of fluid.

1 . A valve opening/closing control device comprising:
 a driving rotary body rotatable in synchronism with a crankshaft of an internal combustion engine and rotatable also about a rotational axis;   a driven rotary body rotatable in unison with a cam shaft of the internal combustion engine about the rotational axis and rotatable also relative to the driving rotary body within this driving rotary body;   a fluid pressure chamber formed by the driving rotary body and the driven rotary body;   a partitioning portion provided within the fluid pressure chamber for partitioning the fluid pressure chamber into a retard chamber and an advance chamber allowing introduction and discharge of fluid thereto/therefrom, the partitioning portion selectively displacing relative rotation phase of the driven rotary body relative to the driving rotary body in a retard direction in which capacity inside the retard chamber is increased in association with introduction of the fluid or an advance direction in which capacity inside the advance chamber is increased in association with introduction of the fluid;   the driving rotary body including an aluminum housing having a pulley that inputs drive force from the crankshaft via a drive belt and a plate attached to at least one face of the housing extending along the rotational axis; and   a gap allowing outflow of the fluid therethrough being provided between the housing and the plate.   
     
     
         2 . The valve opening/closing control device of  claim 1 , wherein the pulley is subjected to an alumite treatment in advance. 
     
     
         3 . The valve opening/closing control device of  claim 1 , wherein at least one of a contacting face of the housing and a contacting face of the plate is provided as an alumite-treated surface having a predetermined surface roughness; and the contacting face of the housing and the contacting face of the plate are placed in direct contact with each other. 
     
     
         4 . The valve opening/closing control device of  claim 1 , wherein:
 the partitioning portion is provided in the driven rotary body;   the housing includes a cylindrical wall portion having, in its inner circumferential face, a sliding contacting area where the housing comes into sliding contact with the partitioning portion;   between the pulley and the cylindrical wall portion, there is formed a groove portion that penetrates in the direction of the rotational axis and extends in a circumferential direction relative to the rotational axis; and   the groove portion and the sliding contacting area have a mutually overlapped area in a radial direction of the rotational axis.   
     
     
         5 . The valve opening/closing control device of  claim 4 , wherein a width of the groove portion along the radial direction of the rotational axis is set greater than a width of the contacting face of the housing that comes into contact with the plate along the radial direction.