Valve timing adjustment device

A valve timing adjustment device configured to adjust an opening timing and a closing timing of a valve, which is installed at an internal combustion engine, relative to a rotational phase of a drive shaft of the internal combustion engine, the valve timing adjustment device comprising:

• a hydraulic oil control valve that includes:
• an outer sleeve that is shaped in a tubular form and has a projection at an outer periphery of the outer sleeve;
• an inner sleeve that is located on an inner side of the outer sleeve;
• and
• a spool that is located at an inside of the inner sleeve and is configured to reciprocate forward and backward along a rotational axis of the outer sleeve, wherein the inner sleeve and the outer sleeve are assembled together to form a plurality of ports, each of which serves as an oil passage, and a hydraulic oil pressure of hydraulic oil, which is supplied from a hydraulic oil supply source through corresponding one or more of the plurality of ports, is controlled by reciprocating the spool forward or backward;
• an actuator that is configured to control reciprocation of the spool;
• and
• a vane rotor that is installed between a driven shaft and the drive shaft while the driven shaft is configured to open and close the valve in response to rotation of the drive shaft, wherein the vane rotor is configured to change a rotational phase of the driven shaft relative to the drive shaft according to the hydraulic oil pressure of the hydraulic oil supplied from the hydraulic oil control valve, wherein:
• a reference-shape portion, which serves as a reference at a time of positioning the outer sleeve relative to the inner sleeve, is formed at an outer periphery of the projection;
• and
• a seat surface of the projection, which fixes the vane rotor between the seat surface of the projection and an end portion of one of the drive shaft and the driven shaft, is shaped in a rotationally symmetric form that is rotationally symmetric around the rotational axis.