Abstract: A pump housing of an oil pump includes a suction port that supplies oil to a pump room, a discharge port that discharges oil from the pump room, and a seal portion that suppresses leakage of oil from the pump room to outside of the pump room. A shaft of the oil pump includes a small diameter portion and a large diameter portion having different diameters, the small diameter portion is connected to the inner rotor, and the shaft and the inner rotor integrally rotate. The seal portion is in contact with a side surface of the inner rotor extending in a diameter direction of the shaft, and also extends to a region in the diameter direction on an inner side smaller than the large diameter portion in the diameter direction.

Abstract: A pump housing of an oil pump includes a suction port that supplies oil to a pump room, a discharge port that discharges oil from the pump room, and a seal portion that suppresses leakage of oil from the pump room to outside of the pump room. A shaft of the oil pump includes a small diameter portion and a large diameter portion having different diameters, the small diameter portion is connected to the inner rotor, and the shaft and the inner rotor integrally rotate. The seal portion is in contact with a side surface of the inner rotor extending in a diameter direction of the shaft, and also extends to a region in the diameter direction on an inner side smaller than the large diameter portion in the diameter direction.

Abstract: A variable oil pump includes a pump housing, a cover, an oil pump rotor rotationally driven while housed in a housing space between the pump housing and the cover, an adjustment member housed in the housing space to adjust the amount of oil discharged from the oil pump rotor by being displaced due to a drive force while rotatably holding the oil pump rotor from an outer peripheral side, and a guide portion including a groove in the adjustment member and a pin on the pump housing that engage one another. Engagement of the pin and the groove guides displacement of the adjustment member relative to the pump housing. A seal structure on at least one of the pump housing and the cover seals the inside of the groove relative to the housing space by surrounding a movement trajectory of the groove relative to the pin.

Abstract: A variable oil pump includes a pump rotor housed in a housing and rotationally driven, an adjustment ring that adjusts an amount of oil discharged from the pump rotor by being displaced under hydraulic pressure supplied to a hydraulic chamber between the housing and the pump rotor in a state where the pump rotor is rotatably held from an outer peripheral side, and a vane provided in a portion where the adjustment ring and the housing face each other and that seals oil leakage to an outside of the hydraulic chamber. The adjustment ring includes a vane holding portion that holds the vane and an oil passage through which the hydraulic pressure in the hydraulic chamber is drawn into the vane holding portion.

Abstract: A relief valve includes a housing including an internal flow passage through which a working fluid flows, and a relief port discharging the working fluid from the internal flow passage, and a valve body including a first pressure-receiving portion a second pressure-receiving portion receiving pressure with a pressure-receiving area that is larger than a pressure-receiving area of the first pressure-receiving portion, and a first recessed portion formed at the second pressure-receiving portion at an opposite side relative to a pressure-receiving surface of the second pressure-receiving portion and including a closed-end cylindrical shape. The relief valve includes a biasing force adjustment mechanism including a spring of which one end is held at the first recessed portion, a support portion retaining the other end of the spring and including a closed-end cylindrical shape, and a motor adjusting a rotational angle and causing the support portion to reciprocate.

Abstract: A variable oil pump includes a pump housing, a cover, an oil pump rotor rotationally driven while housed in a housing space between the pump housing and the cover, an adjustment member housed in the housing space to adjust the amount of oil discharged from the oil pump rotor by being displaced due to a drive force while rotatably holding the oil pump rotor from an outer peripheral side, and a guide portion including a groove in the adjustment member and a pin on the pump housing that engage one another. Engagement of the pin and the groove guides displacement of the adjustment member relative to the pump housing. A seal structure on at least one of the pump housing and the cover seals the inside of the groove relative to the housing space by surrounding a movement trajectory of the groove relative to the pin.

Abstract: A variable oil pump includes a pump rotor housed in a housing and rotationally driven, an adjustment ring that adjusts an amount of oil discharged from the pump rotor by being displaced under hydraulic pressure supplied to a hydraulic chamber between the housing and the pump rotor in a state where the pump rotor is rotatably held from an outer peripheral side, and a vane provided in a portion where the adjustment ring and the housing face each other and that seals oil leakage to an outside of the hydraulic chamber. The adjustment ring includes a vane holding portion that holds the vane and an oil passage through which the hydraulic pressure in the hydraulic chamber is drawn into the vane holding portion.

Abstract: Provided is a fluid-pump inner rotor that can be easily fitted to an outer rotor. This fluid-pump inner rotor includes a rotor member having a through hole along a rotational axis and a shaft member fitted in the through hole. Fitting strength between a first hole region provided in an inner face of the through hole of the rotor member which region extends along a rotational axis of the rotor member from one of end faces thereof perpendicular to this rotational axis and a first shaft region provided in an outer face of the shaft member is set greater than fitting strength between a second hole region provided in the inner face of the through hole of the rotor member and a second shaft region provided in the outer face of the shaft member.

Abstract: A relief valve includes a housing including an internal flow passage through which a working fluid flows, and a relief port discharging the working fluid from the internal flow passage, and a valve body including a first pressure-receiving portion a second pressure-receiving portion receiving pressure with a pressure-receiving area that is larger than a pressure-receiving area of the first pressure-receiving portion, and a first recessed portion formed at the second pressure-receiving portion at an opposite side relative to a pressure-receiving surface of the second pressure-receiving portion and including a closed-end cylindrical shape. The relief valve includes a biasing force adjustment mechanism including a spring of which one end is held at the first recessed portion, a support portion retaining the other end of the spring and including a closed-end cylindrical shape, and a motor adjusting a rotational angle and causing the support portion to reciprocate.

Abstract: Provided is a fluid-pump inner rotor that can be easily fitted to an outer rotor. This fluid-pump inner rotor includes a rotor member having a through hole along a rotational axis and a shaft member fitted in the through hole. Fitting strength between a first hole region provided in an inner face of the through hole of the rotor member which region extends along a rotational axis of the rotor member from one of end faces thereof perpendicular to this rotational axis and a first shaft region provided in an outer face of the shaft member is set greater than fitting strength between a second hole region provided in the inner face of the through hole of the rotor member and a second shaft region provided in the outer face of the shaft member.