The present invention relates to a hydraulic-oil control device that performs hydraulic-oil supply control in a dual clutch device having a first clutch and a second clutch. The hydraulic-oil control device 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 bulldozer includes a steering clutch, a steering brake, a hydraulic pump that discharges a lubricating oil, a first lubricating oil supply path, a second lubricating oil supply path, a third lubricating oil supply path, and a flow amount switching valve disposed on the second lubricating oil supply path. The first lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering clutch The second lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering brake. The third lubricating oil supply path supplies, to the steering brake, a portion of the lubricating oil that has passed through the steering clutch. The flow amount switching valve switches an amount of the lubricating oil supplied to the steering brake.

The invention relates to a hydraulic assembly for driving a friction clutch, comprising a hydraulically driveable actuator cylinder, a pump driving the actuator cylinder, wherein the actuator cylinder has a working piston with a working chamber and the working piston moveably arranged in the working chamber divides said working chamber into a main chamber and an auxiliary chamber, at least one control valve which is designed as a multi-port valve and arranged in the line path between the actuator cylinder and the pump, wherein a first supply line leads from the pump to the control valve, whereby a line path is created via a second supply line in a first valve position of the control valve, which leads to the main chamber of the actuator cylinder. In addition, in a second valve position of the control valve, the auxiliary chamber of the working chamber can be fluidically connected to the line path of the first and second supply lines via a first discharge line, while simultaneously, in the second valve position, the main chamber is connected via the first and second supply lines by means of the pump.

Disclosed is an exemplary hydraulic system including a first fluid circuit and a first pump fluidly connected to the first fluid circuit. The first pump configured to produce a fluid output at a first flow rate when operated at a selected speed. The hydraulic system further includes a second fluid circuit and a second pump selectively fluidly connectable to the first fluid circuit and the second fluid circuit. The second pump configured to produce a fluid output at a second flow rate when operated at the selected speed, with the second flow rate being greater than the first flow rate of the first pump. A first valve fluidly connects the second pump to the first fluid circuit when the first valve is arranged in an open position, and fluidly connects the second pump to second fluid circuit when the first valve is arranged in a closed position.

A shut-off valve for shutting-off a supply at will, wherein the shut-off valve comprises an axially movable valve slide, provided with a transverse valve flange for cooperation with a fixed valve seat, the slide being aetuatable in a closing direction by spring force and in an opening direction by a hydraulically operated ball, having an actuation end position in a sealing ball seat.

An energy recovery system having an energy source/sink and an energy storage system is disclosed. The energy recovery system includes a frictional engagement device adapted for the transmission of energy between an energy source/sink and the energy storage system, a cooling fluid supply for the frictional engagement device, an element for controlling the power flow through the frictional engagement device, an element for varying the flow of cooling fluid from the fluid supply to the frictional engagement device whereby the flow of fluid to the frictional engagement device is made to increase when the magnitude of power through the frictional engagement device is made to increase.

A hydraulic system for an automatic gearbox for a motor vehicle, includes a high-pressure circuit which includes a pressure accumulator, at least one clutch and actuators, and a low-pressure circuit for cooling the clutch, the high-pressure circuit and the low-pressure circuit each containing a hydraulic cooling pump and a hydraulic charging pump that can be driven by a shared electric motor; and a controller which, when it is detected that the pressure accumulator needs to be charged, controls the electric motor to run at a charging setpoint speed, and/or, when it is detected that cooling is needed or another need exists, controls the electric motor to run at a cooling setpoint speed or another setpoint speed. When the pressure accumulator does not need to be charged and there is no need for cooling and no other need, the controller reduces the setpoint speed to zero for a specified period. At the end of the period the controller controls the electric motor to run at least at the test speed.

According to an embodiment, a valve assembly is provided for use with a fluid system for controlling flow rate to a fluid circuit for cooling and/or lubricating a clutch assembly in a transmission. The spool valve has a first outlet and a second outlet in fluid communication with the fluid circuit. The spool valve has a first configuration with zero flow to the fluid circuit, a second configuration providing a first flow to the fluid circuit through the first outlet, and a third configuration providing a second flow to the fluid circuit through the first and second outlets. The first outlet has a metering orifice. The flow across the valve is a function of the stroke distance of the spool.

A transmission system comprising: a lubrication valve that fluidly couples a lubrication line in fluidic communication with a multi-disc wet clutch; a clutch line in fluidic communication with a clutch actuator of the multi-disc wet clutch and the lubrication valve; a clutch control valve fluidly coupled to the clutch line; and a controller configured to adjust a pressure of the clutch line to open and close the lubrication valve based on wet clutch temperature.

A method for detecting a safe state of a switchable valve of a hydraulic system of an actuator in a motor vehicle includes the at least one first switchable valve, which is actuated by being energized, a pump, and a controller which controls at least the first switchable valve and the pump. The pump delivers the fluid to a first load in a first rotational direction and to at least one second load in a second rotational direction.