JP-B2-2760637 (U.S. Pat. No. 5,117,785) describes a fluid-pressure-operated valve timing controller having a housing rotating with a crankshaft and a vane rotor rotating with a camshaft. The vane rotor defines operation chambers inside the housing. The vane rotor is rotated in the circumference direction relative to the housing by working fluid flowing into or out of the operation chambers, thus the rotation phase of the vane rotor relative to the housing is controlled.
The fluid-pressure-operated valve timing controller is equipped with a control valve extending in the vane rotor and the camshaft. The control valve has a sleeve and a spool, and controls the flow of working fluid relative to the operating chambers by controlling the axial movement of the spool in the sleeve. The sleeve has a valve part on the first end in the axial direction and a screw part on the second end in the axial direction. The valve part is held by the vane rotor and accommodates the spool in the slidable state. The screw part is coaxially secured to the camshaft. The sleeve is constructed such manner that the valve part and the screw part are connected with each other in the axial direction, thereby working as a connector connecting the vane rotor to the camshaft. Thus, the number of components for producing the valve timing controller is reduced, and the size of the valve timing controller is made smaller.
However, axial tension generated by securing the screw part to the camshaft may be transmitted to the valve part. If the valve part is deformed, the sliding movement of the spool may be affected, and the control accuracy of the valve timing may be lowered because the controllability of the working fluid by the control valve may be lowered.
USPTO Backgrounds
USPTO Backgrounds