A hydraulic control system for a motor vehicle transmission includes a pressure regulation subsystem in fluid communication with a pump for providing pressurized hydraulic fluid. A manual valve assembly is in direct fluid communication with the pressure regulation subsystem, and is moveable by an operator of the motor vehicle between at least park, neutral, drive, and reverse positions. A default disable valve assembly is in direct fluid communication with the manual valve assembly, a default disable solenoid, and a default select valve assembly. The manual valve assembly is in direct fluid communication with the default disable valve assembly which is in direct fluid communication with the default disable solenoid and the default select valve assembly. The default disable solenoid enables the default disable valve assembly to enable three default modes of operation and the default select valve assembly selects between two of the three default modes of operation.

A method for controlling a line pressure of a hybrid vehicle includes applying, by a controller, a set current corresponding to a target pressure to a first solenoid valve controlling the line pressure, driving, by the controller, a second solenoid valve to open an engine clutch after the applying step, comparing, by the controller, a difference value between a real pressure of the engine clutch sensed by a pressure sensor and the target pressure with a preset pressure after the driving step, and as a result of performing the comparing step, if the difference value is equal to or greater than the preset pressure, controlling, by the controller, an increase of a revolution per minute (RPM) speed of the electric oil pump and an increase of a pressure of the first solenoid valve to be alternately generated.

A pressure control system for a torque control device includes a control pressure regulating valve (110) outputting a control pressure, a pressure switching valve (120) and a jointing pressure regulating valve (130) connected to a piston chamber of the torque control device. When the control pressure is lower than a set value of a spring of the pressure switching valve, the jointing pressure regulating valve (130) outputs jointing pressure that is in fixed proportion with the control pressure. When the control pressure reaches the set value of the spring of the pressure switching valve, the jointing pressure regulating valve (130) outputs a jointing pressure that is larger than the fixed proportion with the control pressure. The pressure control system ensures that the torque control device has both precise and large torque capacity.

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 failsafe multimode clutch assembly positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling having a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly uses pressurized lubricating oil to shift the bypass assembly between the engaged position and a disengaged position. A lock assembly enables and disables actuation of the bypass assembly. In the disengaged position, the overrunning mode of the freewheeling unit enables a unidirectional torque transfer mode of the clutch assembly. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.

A hydraulic clutch assembly can include a shaft defining a shaft channel, one or more hydraulic ports defined through the shaft, and one or more lubrication holes defined through the shaft. A porting manifold can be disposed at least partially within the shaft channel. The porting manifold can include a control pressure path in fluid communication with the one or more hydraulic ports and a lubrication flow path in fluid communication with the one or more lubrication holes. The control pressure path and the lubrication path can be fluidly isolated in the porting manifold.

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.

A wet clutch assembly can include a clutch pack having a plurality of friction members attached to a first clutch housing and a plurality of separator members attached to a second clutch housing. The friction members and the separator members can be configured to be selectively contacted to each other to engage the first housing member to the second housing member. The clutch pack can be in fluid communication with a lubrication source such that a lubrication flow can flow to the friction members and the separator members to remove heat and/or debris therefrom.

A clutch for a rotary shaft includes an annular pressure chamber with a sleeve surface engaging a surface to drivingly connect the shaft to the clutch, and further includes a trigger device and a channel system activatable by the trigger device upon a relative angular movement between the shaft and the chamber to release the shaft from the housing. The trigger device has a cam wheel having a constant first radius across a first angular interval and a second, smaller, radius across a second angular interval. The cam wheel is supported on an envelope surface within the first angular interval and rotating in relation to the envelope surface when the shaft rotates in relation to the housing. When a contact point reaches the second angular interval, the cam wheel is displaced to activate said channel system.

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.