A first valve is disposed in an oil passage through which the engaging pressure generated by a linear solenoid valve is supplied to A second brake. The first valve is closed when the second brake is released, so as to close the oil passage, and is opened when the second brake is engaged, so as to open the oil passage. A second valve is disposed in a lubricating oil passage through which lubricating oil is supplied to the second brake, and communicates with the linear solenoid valve. The second valve is opened when the engaging pressure is supplied from the linear solenoid valve, so as to open the lubricating oil passage, and is closed when no engaging pressure is generated by the linear solenoid valve.

A method controls a hydraulic system for an actuation device and a cooling and/or lubricating device of a motor vehicle. The hydraulic system has a pump, multiple first actuation valves which are each arranged between a system rail connected to a pump outlet and a hydraulic consumer, as well as an additional valve which is arranged between the pump outlet and a coolant and/or lubricant supply line. The pump is switched between a normal operation and an enhanced operation according to an existing total energy demand of the hydraulic consumer. In normal operation, the pump is permanently driven and the additional valve is opened and closed to control pressure in the system rail. In enhanced operation, the pump is permanently driven, the additional valve is permanently closed and each of the actuation valves is operated according to an individual energy demand of the respective hydraulic consumer.

Proposed is a system for operating and lubricating a clutch of a work vehicle. The system includes a forward-backward switching clutch portion connected to a first transmission hydraulic line, a main transmission clutch portion connected to the first transmission hydraulic line so as to be disposed in parallel with the forward-backward switching clutch portion, an auxiliary transmission clutch portion connected to a second transmission hydraulic line disposed in parallel with the first transmission hydraulic line, and a lubricating oil supply portion configured to supply oil as a lubricant to each clutch friction element. The lubricating oil supply portion includes a clutch lubrication valve unit, and is configured to always allow oil supply to the clutch friction elements of each of the main transmission clutch portion and the auxiliary transmission clutch portion, and is configured to intermittently allow oil supply to the clutch friction element of the forward-backward switching clutch portion.

A drive train unit for a vehicle includes a housing, an input shaft rotatably mounted in the housing and arranged for rotationally fixed attachment to an output of a transmission, a first clutch operable between a rotor of an electric machine and the input shaft, and a coolant delivery device integrated in the housing. The coolant delivery device is arranged to generate a coolant circuit from the input shaft outwardly in a radial direction when the input shaft is rotated. The coolant delivery device has a discharge element for deflecting coolant flowing in a circumferential direction into a channel inwardly in the radial direction. The drive train unit may include the electric machine with the rotor. The drive train may have an output shaft and a second clutch operable between the input shaft and the output shaft.

A drive train unit for a vehicle includes a housing, an input shaft rotatably mounted in the housing and arranged for rotationally fixed attachment to an output of a transmission, a first clutch operable between a rotor of an electric machine and the input shaft, and a coolant delivery device integrated in the housing. The coolant delivery device is arranged to generate a coolant circuit from the input shaft outwardly in a radial direction when the input shaft is rotated. The coolant delivery device has a discharge element for deflecting coolant flowing in a circumferential direction into a channel inwardly in the radial direction. The drive train unit may include the electric machine with the rotor. The drive train may have an output shaft and a second clutch operable between the input shaft and the output shaft.

A clutch assembly includes a shaft, a backing plate fixed to the shaft, a plurality of clutch plates, a hydraulic piston, and a balance dam. The hydraulic piston is sealed to the shaft and axially slidable on the shaft to clamp the plurality of clutch plates against the backing plate to close the clutch assembly. The balance dam is fixed to the shaft and disposed axially between the backing plate and the hydraulic piston. The balance dam has a cooling flow orifice and a cooling flow valve for adjusting cooling oil flow through the cooling flow orifice. In some example embodiments, the cooling flow valve is a reed valve with a displaceable steel plate fixed to the balance dam and preloaded against the balance dam to cover the cooling flow orifice.

A lubrication system for a power transmission unit that supplies oil to a starting clutch in an appropriate amount irrespective of an engagement state of the starting clutch. When the friction clutch is completely engaged or disengaged, a first control valve is brought into a low inflow rate mode, and the second control valve is brought into a low outflow rate mode. When the friction clutch is engaged while causing a slip the first control valve is brought into a high inflow rate mode, and the second control valve is brought a high outflow rate mode.

A hydraulic component includes a piston and a cylinder with a piston receiving space in which the piston is displaceably arranged while defining a chamber, via which a pressure may be applied to a first end face of the piston, from a control chamber, via which pressure may be applied to a second end face of the piston which faces away from the first end face. A first hydraulic line and a second hydraulic line open into the chamber and a control line, which branches off from the first hydraulic line, opens into the control chamber. Due to the respective pressure ratio between the pressure in the chamber and the control chamber, the piston is displaceable from a closed position, in which the first and second hydraulic lines are fluidly decoupled, into an open position, in which the first and second hydraulic lines are fluidly connected, and vice versa.

Hydraulic-oil control devices are provided herein that perform hydraulic-oil supply control in a dual clutch device having a first clutch and a second clutch. A hydraulic-oil control device according to embodiments herein includes a first linear solenoid valve that adjusts hydraulic oil having a line pressure for a first hydraulic chamber and supplies the hydraulic oil thereto, a second linear solenoid valve that adjusts hydraulic oil having a line pressure for a second hydraulic chamber and supplies the hydraulic oil thereto, a shuttle valve that outputs the hydraulic oil having a higher pressure between the pressure of the hydraulic oil in the first hydraulic chamber and the pressure of the hydraulic oil in the second hydraulic chamber, and a switch valve that adjusts the amount of hydraulic oil supplied to a first space and a second space, according to the pressure of the hydraulic oil output from the shuttle valve.

A rear axle drive (2) for an AWD vehicle is presented. The rear axle drive (2) is connected to an hydraulic AWD coupling (3), wherein the rear axle drive (2) comprises a lubrication valve (4) for controlling the level of lubricant in at least one lubricant reservoir (6, 7) of the rear axle drive (2) for providing lubricant to gears and/or bearings of the rear axle drive (2). The lubrication valve (4) is functionally connected to a shut-off valve (5) of the AWD coupling (3) and the lubrication valve (4) of the rear axle drive (3) is controlled by movement of an actuating member (51, 54) of the AWD coupling (3).