Hydraulic oil control valve and valve timing adjustment device

Abstract

A hydraulic oil control valve is coaxially disposed with a rotational axis of a valve timing adjustment device for adjusting valve timing of a valve. The valve is selectively opened or dosed by a drive shaft receiving a driving force from a drive shaft. The hydraulic oil control valve includes a tubular sleeve and a spool that is slidably moved within the sleeve. The sleeve includes an inner sleeve and an outer sleeve that is fixed to an end portion of one of the drive shaft and the driven shaft with an axial force. When the axial force is not applied, a minimum clearance between the outer sleeve and the inner sleeve in a radial direction is larger than a minimum clearance between the inner sleeve and the spool in the radial direction.

What is claimed is: 
     
         1 . A hydraulic oil control valve for a valve timing adjustment device, the valve timing adjustment device being configured to adjust valve timing of a valve and fixed to an end portion of one shaft that is a drive shaft or a driven shaft, the driven shaft being configured to selectively open and close the valve with a driving force transmitted from the drive shaft, the hydraulic oil control valve being coaxially disposed with a rotational axis of the valve timing adjustment device and configured to control a flow of a hydraulic oil supplied from a hydraulic oil supply source, the hydraulic oil control valve comprising:
 a tubular sleeve; and   a spool that has an end portion in contact with an actuator and that is slidably moved by the actuator in an axial direction within the sleeve, wherein   the sleeve includes:
 an inner sleeve disposed radially outside of the spool; and 
 an outer sleeve defining an axial hole therein extending in the axial direction, the inner sleeve being inserted into at least a portion of the axial hole, 
   the outer sleeve is configured to be fixable to the end portion of the one shaft by an axial force applied to the outer sleeve in the axial direction, and   in absence of the axial force, a minimum clearance in a radial direction between the outer sleeve and the inner sleeve is larger than a minimum clearance in the radial direction between the inner sleeve and the spool,   
     
     
         2 . The hydraulic oil control valve according to  claim 1 , wherein
 the inner sleeve has a coefficient of linear expansion greater than that of the outer sleeve.   
     
     
         3 . The hydraulic oil control valve according to claim wherein
 the outer sleeve is harder than the inner sleeve.   
     
     
         4 . The hydraulic oil control valve according to  claim 1 , wherein
 the outer sleeve is made of iron, and   the inner sleeve is made of aluminum or resin,   
     
     
         5 . A hydraulic oil control valve for a valve timing adjustment device, the valve timing adjustment device being configured to adjust valve timing of a valve and fixed to an end portion of one shaft that is a drive shaft or a driven shaft, the driven shaft being configured to selectively open or close the valve with a driving force transmitted from the drive shaft, the hydraulic oil control valve being coaxially disposed with a rotational axis of the valve timing adjustment device and configured to control a flow of a hydraulic oil supplied from a hydraulic oil supply source, the hydraulic oil control valve comprising:
 a tubular sleeve; and   a spool that has an end portion in contact with an actuator and that is slidably moved by the actuator in an axial direction within the sleeve, wherein   the sleeve includes:
 an inner sleeve disposed radially outside of the spool; and 
 an outer sleeve defining an axial hole therein extending in the axial direction, the inner sleeve being inserted into at least a portion of the axial hole, 
   the outer sleeve is configured to be fixable to the end portion of the one shaft of the drive shaft or the driven shaft by an axial force applied to the outer sleeve in the axial direction,   when a predetermined condition is satisfied, the outer sleeve is in contact with the inner sleeve in a radial direction, and   the predetermined condition includes a condition where the axial force is applied to the outer sleeve,   
     
     
         6 . The hydraulic oil control valve according to  claim 5 , wherein
 an ambient temperature is defined as an ambient temperature at which the valve timing adjustment device is used, and   the predetermined condition further includes a condition where the ambient temperature after the axial force is applied to the outer sleeve is increased compared to the ambient temperature prior to applying the axial force to the outer sleeve.   
     
     
         7 . The hydraulic oil control valve according to  claim 5 , wherein
 the inner sleeve has a coefficient of linear expansion greater than that of the outer sleeve, and   the spool has a coefficient of linear expansion same as or similar to that of the outer sleeve.   
     
     
         8 . The hydraulic oil control valve according to  claim 7 , wherein
 the outer sleeve and the spool are made of iron, and   the inner sleeve is made of aluminum or resin.   
     
     
         9 . A valve timing adjustment device comprising
 a hydraulic oil control valve according to  claim 1 .