A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.

An oil pump that sucks and discharges oil, includes: a housing portion; a stator portion including an outer ring that is accommodated inside the housing portion, and a main pressing end that is formed to protrude outward from an outer circumferential surface of the outer ring; a rotor portion accommodated inside the outer ring, and sucking and discharging oil through rotation; a spring portion including a main spring that presses the stator portion; a guiding portion including a first guiding member that is installed on the outer circumferential surface of the outer ring; and a sealing portion interposed between the housing portion and a stator portion to prevent the oil flowing into the variable chamber from leaking into another space between the housing portion and the stator portion.

An oil pump that sucks and discharges oil, includes: a housing portion; a stator portion including an outer ring that is accommodated inside the housing portion, and a main pressing end that is formed to protrude outward from an outer circumferential surface of the outer ring; a rotor portion accommodated inside the outer ring, and sucking and discharging oil through rotation; a spring portion including a main spring that presses the stator portion; a guiding portion including a first guiding member that is installed on the outer circumferential surface of the outer ring; and a sealing portion interposed between the housing portion and a stator portion to prevent the oil flowing into the variable chamber from leaking into another space between the housing portion and the stator portion.

A gerotor pump includes a casing including a pumping chamber, a fixed gear being inserted into the casing and rotating at a fixed position, including a plurality of teeth formed inside a cylinder, and including at least one fluid hole at one end of the cylinder to allow a fluid to flow from the pumping chamber or into the pumping chamber, a moving gear provided inside the fixed gear and including one less number of teeth than a number of the plurality of teeth of the fixed gear and movable in an axial direction, a gear block arranged inside the fixed gear and movable in the axial direction, a gear ring arranged outside the moving gear and movable with respect to the moving gear in the axial direction, a gear ring cover provided at one end of the casing and including a hole in which the gear ring is rotated.

A gerotor pump includes a casing including a pumping chamber, a fixed gear being inserted into the casing and rotating at a fixed position, including a plurality of teeth formed inside a cylinder, and including at least one fluid hole at one end of the cylinder to allow a fluid to flow from the pumping chamber or into the pumping chamber, a moving gear provided inside the fixed gear and including one less number of teeth than a number of the plurality of teeth of the fixed gear and movable in an axial direction, a gear block arranged inside the fixed gear and movable in the axial direction, a gear ring arranged outside the moving gear and movable with respect to the moving gear in the axial direction, a gear ring cover provided at one end of the casing and including a hole in which the gear ring is rotated.

A variable displacement gear pump comprises a fixed gear, a movable gear movable, a fixed gear ring fitted over the movable gear, a movable gear ring fitted over the fixed gear, a fixed cover having a hole in which the fixed gear ring rotates, a movable cover having a hole in which the movable gear ring rotates, a fixed gear block attached to the fixed cover, and a movable gear block attached to the movable cover. The fixed gear is engaged with the movable gear. The movable gear ring rotates in the hole of the movable cover, and the fixed gear ring rotates in the hole of the fixed cover. The movable gear, together with the movable cover, the movable gear, and the movable gear block, move along the direction of the shaft to change a width in which the fixed gear is engaged with the movable gear.

A controlled variable delivery external gear machine (VD-EGM). The VD-EGM includes a housing, an inlet, a drive gear, a driven gear, the drive gear configured to engage the driven gear in an angular mesh zone, an outlet, a first slider comprising a first longitudinal portion connected to a second longitudinal portion such that longitudinal forces applied to the first and second longitudinal portions substantially cancel each other thereby requiring between about 0 N to about 20 N to longitudinally moving the first slider, selective positioning of the first slider configured to vary net operational volumes of fluid communication between the inlet and the outlet, for a given rotational speed of the drive gear, and a first drive mechanism coupled to the first slider and configured to cause the first slider to slide in a longitudinal direction.

A controlled variable delivery external gear machine (VD-EGM). The VD-EGM includes a housing, an inlet, a drive gear, a driven gear, the drive gear configured to engage the driven gear in an angular mesh zone, an outlet, a first slider comprising a first longitudinal portion connected to a second longitudinal portion such that longitudinal forces applied to the first and second longitudinal portions substantially cancel each other thereby requiring between about 0 N to about 20 N to longitudinally moving the first slider, selective positioning of the first slider configured to vary net operational volumes of fluid communication between the inlet and the outlet, for a given rotational speed of the drive gear, and a first drive mechanism coupled to the first slider and configured to cause the first slider to slide in a longitudinal direction.

A sliding vane pump includes a fixed housing defining inlet and outlet ports and a sliding housing defining a cylindrical cavity and configured to slide within the fixed housing. The fixed housing and the sliding housing define a gap therebetween. A rotor is configured to rotate within the cylindrical cavity and has a plurality of vanes configured to seal against an inner circumferential wall of the cylindrical cavity to define a plurality of pumping chambers. A seal is located in the gap disposed between the fixed housing and the sliding housing to split the gap into first and second compensation chambers. The first chamber is fluidly connected to a first pumping chamber of the plurality of pumping chambers and the second chamber is connected to a second pumping chamber of the plurality of pumping chambers.

A sliding vane pump includes a fixed housing defining inlet and outlet ports and a sliding housing defining a cylindrical cavity and configured to slide within the fixed housing. The fixed housing and the sliding housing define a gap therebetween. A rotor is configured to rotate within the cylindrical cavity and has a plurality of vanes configured to seal against an inner circumferential wall of the cylindrical cavity to define a plurality of pumping chambers. A seal is located in the gap disposed between the fixed housing and the sliding housing to split the gap into first and second compensation chambers. The first chamber is fluidly connected to a first pumping chamber of the plurality of pumping chambers and the second chamber is connected to a second pumping chamber of the plurality of pumping chambers.