A hydraulic system includes a normally open-type hydraulic clutch which connects or disconnects a power transmission line between an engine and a wheel, an actuator which supplies a hydraulic pressure to the hydraulic clutch, an oil flow path which connects the actuator to the hydraulic clutch, a valve member which is provided on the oil flow path and which enables to switch between an open state where the oil flow path communicates and a closed state where the oil flow path closes, a hydraulic pressure sensor which is provided on the oil flow path, and a bypass flow path which bypasses the valve member. A one-way valve, which permits a supply of a hydraulic pressure from an actuator side to a hydraulic clutch side and which shuts off a supply of a hydraulic pressure from the hydraulic clutch side to the actuator side, is provided on the bypass flow path.

Provided is a system and method for controlling a clutch plate assembly of a vehicle. The system may include a first clutch control system, a second clutch control system, and a valve system. The valve system may have a first input fluidly connected to the first clutch control system for receiving a first pressure from the first clutch control system, a second input configured to be fluidly connected to the second clutch control system for receiving a second pressure from the second clutch control system, and an output configured to be fluidly connected to the clutch plate assembly. The valve system may be configured to provide at least a portion of at least one of the first pressure and the second pressure to the clutch plate assembly.

A hydraulic control device with a pressure control valve that has a control piston and a modulating piston which can move relative to one another. The control piston and the modulating piston are pushed apart from one another by at least one spring. At one end face of the modulating piston there is arranged a pressure chamber in such a manner that when the pressure chamber is filled, the modulating piston is caused to move in the direction toward the control piston. The pressure chamber can be filled by a first volume flow Q1 of a pressure medium. A venting line, with at least one further throttle, is connected to the pressure chamber. A second volume flow Q2 can be discharged, via the venting line, from the pressure chamber. The hydraulic control device can be utilized in a marine transmission.

A check valve assembly for controlling a flow of fluid in a transmission from a first cavity to a second cavity is disclosed. Check valve assembly may include a housing having a fluid passageway therein, a biasing member supported by the housing for axial movement along a first axis, and a valve element positioned within the fluid passageway of the housing. The valve element may be moveable between a seated position and an unseated position. An intersection of a plane normal to the first axis and the valve element defines a seating boundary of the element, which may define a minimum distance from the seating surface of the fluid passageway to the valve element when the valve element is in the unseated position. The check valve may include at least one swage extending radially inwardly from the fluid passageway to limit axial movement of the valve element.

The present disclosure describes a hydraulic control system comprising a first pressure chamber and a second pressure chamber, each pressure chamber configured to receive a hydraulic fluid, a first movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the first pressure chamber and a second movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the second pressure chamber, a hydraulic command circuit configured to provide the hydraulic fluid and to control the hydraulic pressure of the hydraulic fluid in the first pressure chamber and/or the second pressure chamber, having a switchable valve in fluid communication with the first pressure chamber, wherein the switchable valve is configured to be pilotable depending on the hydraulic pressure of the hydraulic fluid in the second pressure chamber.

Actuation of a hydraulic device that provides a hydraulic supply to a torque-transmitting device is provided. An electrically operated pump is operated in a first operating state. The first operating state; has a primary pump rotational speed that provides a first fluid pressure to the torque-transmitting device via a fluid tract. A switchover process is initiated to operate the electrically operated pump device in a second operating state based on a second fluid pressure and a second fluid target pressure. The second operating state has a secondary pump rotational speed that provides the second fluid pressure to the torque-transmitting device via the fluid tract. During operation of the hydraulic device, the secondary pump rotational speed for the switchover process is determined based on a first power value. The first power value includes electrical pump power of the pump device in a preceding switchover process.

The present disclosure describes a hydraulic control system comprising a first pressure chamber and a second pressure chamber, each pressure chamber configured to receive a hydraulic fluid, a first movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the first pressure chamber and a second movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the second pressure chamber, a hydraulic command circuit configured to provide the hydraulic fluid and to control the hydraulic pressure of the hydraulic fluid in the first pressure chamber and/or the second pressure chamber, having a switchable valve in fluid communication with the first pressure chamber, wherein the switchable valve is configured to be pilotable depending on the hydraulic pressure of the hydraulic fluid in the second pressure chamber.

This clutch control device includes an engine (13), a transmission (21), a clutch device (26) configured to connect and disconnect motive power transmission between the engine (13) and the transmission (21), a clutch actuator (50) configured to drive the clutch device (26) and change a clutch capacity, a hydraulic circuit (63) provided between the clutch device (26) and the clutch actuator (50), an air bleeding device (64) configured to perform air bleeding of the hydraulic circuit (63), a control unit (60) configured to calculate a control target value of the clutch capacity, a control mode changeover switch (59) configured to enable a control mode of the control unit (60) to be switched to an air bleeding mode, and an air bleeding switch (65) configured to enable a hydraulic pressure of the hydraulic circuit (63) to increase in the air bleeding mode.

A clutch device includes a plurality of clutches; a plurality of cylinder chambers provided to respectively correspond to the clutches; a pump configured to discharge a hydraulic fluid; a plurality of control valves each of which is configured to control the hydraulic fluid supplied from the pump to a corresponding one of the cylinder chambers; and an oil passage that distributes the hydraulic fluid discharged from the pump, to the control valves. The oil passage includes at least one split point at which the hydraulic fluid discharged from the pump splits. At least one check valve is provided between the at least one split point and at least one control valve among the control valves, the at least one check valve being configured to block a flow of the hydraulic fluid in a direction from the at least one control valve toward the at least one split point.

A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.