A rotary pump includes: a pump housing having a low-pressure inlet and a high-pressure outlet; a delivery rotor rotatable about a rotational axis and including multiple deliverers distributed over the circumference of the rotor for delivering a fluid from the low-pressure inlet to the high-pressure outlet; and a setting element for adjusting the delivery volume of the pump. The inlet end of the setting element includes a first circumferential portion which extends circumferentially in the rotational direction of the rotor and the axial width of which is smaller than the axial width of the deliverers and a second circumferential portion which adjoins the first circumferential portion in the rotational direction and the axial width of which is greater than the axial width of the first circumferential portion.

A rotary pump for delivering fluid includes: a pump housing having a low-pressure inlet and a high-pressure outlet for the fluid to be delivered; and a delivery rotor rotatable about a rotational axis in the pump housing and including a rotor base body and multiple deliverers distributed over the circumference of the rotor base body for delivering fluid from the low-pressure inlet to the high-pressure outlet. When the delivery rotor rotates, the radial and axial outer edges of the deliverers define a delivery region of the pump. The pump includes a flow channeling structure protruding axially into the low-pressure inlet in relation to the rotational axis of the delivery rotor from the pump housing wall in order to influence fluid flowing in the low-pressure inlet. The flow channeling structure arranged axially next to the delivery region and overlaps at least in portions with the delivery region in the radial direction.

Discharge port (26) as arc-recessed discharge portion is formed by cutting on bottom surface (13a) of pump accommodating portion (13) of variable displacement pump. On mounting surface (1b) of housing body (1), first low pressure chamber (281) is formed at position overlapping with discharge port (26) in radial direction of pump structure (14) formed by driving shaft (3), rotor (4) and vanes (5) Drain hole (28b) communicating with low pressure portion located outside housing body (1) is formed on bottom surface (28a) of first low pressure chamber (281) along direction of rotation axis (O1) of pump structure (14). Low pressure portion has pressure that is hydraulic pressure of oil discharged from discharge port (26) or less. Oil from discharge port (26), having higher pressure than first low pressure chamber (281), flows into first low pressure chamber (281) by pressure difference between discharge port (26) and first low pressure chamber (281).

A variable hydraulic pump include a rotor mounted on a pump housing of which a housing spring end is formed, a pivot pin, an outer ring rotatably coupled to the pivot pin and of which a ring spring end is formed, a spring mounted between the housing spring end and the ring spring end, a pressure chamber formed in the pump housing to push the outer ring, a plurality of vane provided to form a plurality of pockets, an input port to supply oil to the plurality of pockets and a discharge port to exhaust oil supplied to the plurality of pockets, wherein at the reference position of the outer ring, the angle between a first imaginary line connecting the center of the rotor and the pivot pin and a second imaginary line connecting the ring spring end and the pivot pin is 0 to 10 degrees.

A pump with variable suction/discharge amount and a transmission drive device and a driving method thereof. The pump is a rotary vane pump having a vane chamber body. The vane chamber body is composed of a fixed wall member, a movable wall member, a movable vane chamber sleeve and a vane rotor. The vane chamber is extendable/retractable in an axial direction of the vane rotor. At least two pumps are assembled in communication with each other to form a closed loop for the active pump to drive the passive pump. In operation, passive the vane chambers of the active pump and the passive pump are automatically extended/retracted and modulated until the driving force and the load resistance achieve a balanced state passive, the vane chambers and the rotational speeds of the active pump and the passive pump are automatically adjusted to be in inverse proportion to each other.

A hydraulic feed device may include a pendulum-slide cell pump having an internal rotor drivingly connected to an external rotor via pendulum slides. A hydraulic positioning device may have a positioning element for changing an eccentricity between the internal rotor and the external rotor. The positioning element may be preloaded by a spring device for setting a maximum eccentricity. The positioning device may have a first pressure adjusting and a second pressure adjusting chamber for adjusting the positioning element. The first pressure adjusting chamber may be permanently hydraulically connected to a pressure side of the pendulum-slide cell pump and configured to hydraulically counteract the spring device. The second pressure adjusting chamber may be controlled via a control valve and hydraulically connected to the pressure side of the pendulum-slide cell pump and configured to hydraulically counteract the spring device.

A solenoid valve includes: a cylindrical spool that has an annular groove in an outer surface and moves along an axial direction under a driving force generated by a current being applied to a solenoid part; a cylindrical sleeve that has a through-hole capable of communicating with the annular groove and houses the spool; and an urging member that urges the spool by an urging force acting in a direction opposite from a direction in which the driving force is generated. When no current is applied to the solenoid part, a part of the through-hole communicates with the annular groove. When a current is applied to the solenoid part, an area of communication between the through-hole and the annular groove increases as the spool moves under the driving force acting against the urging force.

A variable displacement oil pump includes: a variable displacement mechanism that is able to change a discharge amount per rotation of an input shaft. The variable displacement mechanism includes a pump housing, an oil pressure chamber provided in the pump housing, and a capacity adjustment member displaced by oil pressure from the oil pressure chamber. The capacity adjustment member is configured to be operated when receiving control oil pressure that is supplied from a control valve to the oil pressure chamber. The pump housing has an oil release hole that is opened to face the oil pressure chamber and that penetrates a wall section of the pump housing to partially release oil.

A variable displacement vane pump includes a notch portion which is a flow path provided to extend from an initiating end of a discharge port towards a terminating end side of a suction port. The notch portion is formed so that a sectional area of the flow path is smaller than a sectional area of the discharge port at the initiating end thereof and that a length of the flow path in a circumferential direction is 1.5 pitches or larger. The terminating end of the suction port is a point where the vane in the suction area last overlaps the suction port. The initiating end of the discharge port is a point where the vane departed from the suction area first overlaps the discharge port. One pitch is a distance defied in the circumferential direction between adjacent vanes of the plurality of vanes.

A variable displacement oil pump is described. The oil pump has pump body connected to an intake channel and to a delivery channel, a rotor capable of rotating inside the pump body about a rotation axis and provided with a plurality of vanes. The oil pump has an oscillating stator arranged in an eccentric position around the rotor and pivoted inside the pump body at a rotation pin. The oil pump has adjustment means for adjusting the displacement of the oil pump which acts on the oscillating stator to displace it with respect to the rotor and position it in at least one predetermined operative position. The adjustment means has first thrusting means configured to exert a first thrusting action on a first outer surface portion of the oscillating stator arranged on a substantially opposite side with respect to the rotation pin taking as a reference the rotor.