Abstract: In a hydraulic tensioner device in which a high hydraulic pressure chamber is configured between a plunger accommodation hole of a tensioner body accommodating a plunger and the plunger to attenuate reactive force acting on the plunger, the tensioner body includes, in a discharge oil passage for discharging oil leaked from the high hydraulic pressure chamber, a pressure maintenance valve for opening and closing the discharge oil passage, air release passages are formed inside the pressure maintenance valve, and an air release valve for releasing air and preventing air from back flowing is provided in the air release passages.

Abstract: A piston cooling apparatus includes: a main body including a communication passage communicating with an oil path formed in an internal combustion engine; a nozzle pipe portion including an oil injection port configured to inject oil having passed through the communication passage toward a piston; and a filter disposed upstream of the nozzle pipe portion on the flow passage of the oil and including a hole having a smaller diameter than the minimum diameter of the oil injection port, the oil being injected toward the piston from the oil injection port, wherein: the filter is removably mounted on the outer surface of the outer wall portion of the main body existing upstream on the oil flow passage; and the main body is mounted on the internal combustion engine in a state where at least a portion of the filter is inserted into the oil path.

Abstract: In a hydraulic tensioner device in which a high hydraulic pressure chamber is configured between a plunger accommodation hole of a tensioner body accommodating a plunger and the plunger to attenuate reactive force acting on the plunger, the tensioner body includes, in a discharge oil passage for discharging oil leaked from the high hydraulic pressure chamber, a pressure maintenance valve for opening and closing the discharge oil passage, air release passages are formed inside the pressure maintenance valve, and an air release valve for releasing air and preventing air from back flowing is provided in the air release passages.

Abstract: A piston cooling apparatus includes: a main body including a communication passage communicating with an oil path formed in an internal combustion engine; a nozzle pipe portion including an oil injection port configured to inject oil having passed through the communication passage toward a piston; and a filter disposed upstream of the nozzle pipe portion on the flow passage of the oil and including a hole having a smaller diameter than the minimum diameter of the oil injection port, the oil being injected toward the piston from the oil injection port, wherein: the filter is removably mounted on the outer surface of the outer wall portion of the main body existing upstream on the oil flow passage; and the main body is mounted on the internal combustion engine in a state where at least a portion of the filter is inserted into the oil path.