Valve opening and closing timing control device

A valve opening and closing timing control device comprising:

• a drive-side rotary body that rotates synchronously with a crankshaft of an internal combustion engine;
• a driven-side rotary body that is provided inside the drive-side rotary body in a state of being coaxial with a rotation axis of the drive-side rotary body and that rotates integrally with a camshaft for opening and closing a valve;
• an advance chamber and a retard chamber formed between the drive-side rotary body and the driven-side rotary body;
• a lock mechanism that is switchable between a lock state in which a relative rotation phase of the driven-side rotary body with respect to the drive-side rotary body is restrained to an intermediate phase between a most retarded phase and a most advanced phase and a lock release state in which the restraint of the intermediate phase is released;
• a valve unit that includes a fluid supply pipe into which fluid is supplied and a spool movable along a direction of the rotation axis on an outer peripheral side of the fluid supply pipe, and that controls supply of the fluid to and discharge of the fluid from the lock mechanism, the advance chamber, and the retard chamber;
• and
• a tubular valve case that has an internal space extending along the rotation axis inside the driven-side rotary body in a radial direction and that houses the valve unit in the internal space, wherein
• a first opening portion through which the fluid is suppliable to the advance chamber and the retard chamber is formed in the fluid supply pipe,
• a second opening portion that is communicative with the first opening portion through the spool and that communicates with any one of the advance chamber and the retard chamber is formed in the valve case, and
• when the lock mechanism is in the lock state, a flow path cross-sectional area of the first opening portion communicating with the spool is smaller than a flow path cross-sectional area of the second opening portion communicating with the spool.