Valve timing adjustment device

A valve timing adjustment device configured to adjust a valve timing of a valve of an internal combustion engine, comprising:

• a phase shifter that includes a retard chamber and an advance chamber, wherein the phase shifter is configured to adjust the valve timing of the valve by shifting a rotational phase between a drive shaft and a driven shaft of the internal combustion engine with hydraulic oil supplied from a hydraulic oil supply source to the retard chamber and the advance chamber;
• and
• a hydraulic oil controller that is configured to control a flow of the hydraulic oil supplied to the retard chamber and the advance chamber by controlling the hydraulic oil flowing in a retard supply oil passage, which connects between the hydraulic oil supply source and the retard chamber, and the hydraulic oil flowing in an advance supply oil passage, which connects between the hydraulic oil supply source and the advance chamber, wherein:
• the hydraulic oil controller includes:
• a drain port that is connected to an oil discharge portion that is configured to store the hydraulic oil discharged from the retard chamber or the advance chamber;
• a partition that is configured to partition between a drain oil passage and a corresponding one of the retard supply oil passage and the advance supply oil passage, wherein the drain oil passage connects between the oil discharge portion and a corresponding one of the retard chamber and the advance chamber;
• a recycle oil passage that connects between:
• a portion of the drain oil passage located between the partition and the drain port;
• and
• the retard supply oil passage or the advance supply oil passage;
• and
• a drain flow restrictor that is formed in the drain oil passage at a location between the partition and the drain port, wherein a passage cross-sectional area of the drain flow restrictor is smaller than a smallest passage cross-sectional area of the recycle oil passage and is constant.