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.

In a hydraulic control device, when it is detected that a pressure of first oil (output pressure) detected by an output pressure sensor pulsates, a transmission control unit as a TCU stops driving of a second pump or decreases a rotation number of the second pump as a first operation. Alternatively, when it is detected that the output pressure pulsates, the TCU increases the rotation number of the second pump to a rotation number (for example, maximum rotation number) that is higher than a target rotation number as a second operation.

In a hydraulic control device, when it is detected that a pressure of first oil (output pressure) detected by an output pressure sensor pulsates, a transmission control unit as a TCU stops driving of a second pump or decreases a rotation number of the second pump as a first operation. Alternatively, when it is detected that the output pressure pulsates, the TCU increases the rotation number of the second pump to a rotation number (for example, maximum rotation number) that is higher than a target rotation number as a second operation.

A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump.

A positive displacement pump for pumping oil in a motor vehicle transmission comprises a pump stage that has a central kidney-shaped suction cavity and two kidney-shaped pressure cavities. Oil is selectively pumped via one kidney-shaped pressure cavity or the other kidney-shaped pressure cavity in accordance with the direction of rotation of the pump stage. This makes it possible to create, with little complexity, two operating stages for the positive displacement pump.

A positive displacement pump for pumping oil in a motor vehicle transmission comprises a pump stage that has a central kidney-shaped suction cavity and two kidney-shaped pressure cavities. Oil is selectively pumped via one kidney-shaped pressure cavity or the other kidney-shaped pressure cavity in accordance with the direction of rotation of the pump stage. This makes it possible to create, with little complexity, two operating stages for the positive displacement pump.

An external gear machine (EGM) includes a housing, an inlet, a drive gear positioned in the housing and configured to be (i) driven by a mechanism when the EGM is operated as a pump, or (ii) drive an external mechanism when the EGM is operated as a motor, the drive gear having a plurality of teeth, a slave gear positioned in the housing having a plurality of teeth and configured to be driven by the drive gear, an outlet formed in the housing and configured to receive at least some of the volume of fluid via an outlet fluid communication channel, a first slider defining an inlet fluid communication channel and the outlet fluid communication channel, 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.

An external gear machine (EGM) includes a housing, an inlet, a drive gear positioned in the housing and configured to be (i) driven by a mechanism when the EGM is operated as a pump, or (ii) drive an external mechanism when the EGM is operated as a motor, the drive gear having a plurality of teeth, a slave gear positioned in the housing having a plurality of teeth and configured to be driven by the drive gear, an outlet formed in the housing and configured to receive at least some of the volume of fluid via an outlet fluid communication channel, a first slider defining an inlet fluid communication channel and the outlet fluid communication channel, 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.

In a hydraulic control device, when it is detected that a pressure of first oil (output pressure) detected by an output pressure sensor pulsates, a transmission control unit as a TCU stops driving of a second pump or decreases a rotation number of the second pump as a first operation. Alternatively, when it is detected that the output pressure pulsates, the TCU increases the rotation number of the second pump to a rotation number (for example, maximum rotation number) that is higher than a target rotation number as a second operation.