A method of controlling an automatic transmission is provided. The automatic transmission includes first and second frictional engageable elements and a hydraulic mechanism. The method includes controlling a first hydraulic pressure control valve of the first element to adjust hydraulic pressure to a given value in a first period in response to the gear shift command and increase the hydraulic pressure until first friction plates engaged in a second period, and a second hydraulic pressure control valve of the second element to pre-charge in response to the gear shift command, maintain the hydraulic pressure at a lower value than a highest target value immediately after the pre-charging, and increase the hydraulic pressure until second friction plates engaged immediately after the maintaining the pressure, a time length of the first period being shorter than a time length between a start of the pre-charging and a start of the increasing the pressure.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying/discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than the first surface. The method includes controlling the disengaged friction plates to be engaged by adjusting the hydraulic pressure to a first pressure in a first period in response to a gear shift command and adjusting the hydraulic pressure to a second pressure in a second period. The first pressure is changed depending on a state of the automatic transmission.

A clutch assembly for a motor vehicle drive train is provided. The clutch assembly includes a clutch pack; a piston for engaging the clutch pack; a housing including a surface for slidably supporting the piston; a release spring for disengaging the piston from the clutch; and a bearing supporting the clutch pack. The bearing limiting axial movement of the release spring away from the piston. A method of assembling a clutch assembly is also provided.

A wedge friction clutch with onboard enable and disable function, including: an axis of rotation; an inner race; an outer race; a wedge plate located between the inner and outer races in a radial direction; a first resilient element; and a piston. For a locked mode, the first resilient element is arranged to displace the wedge plate in a first circumferential direction to non-rotatably connect the inner and outer races. For a free wheel mode the piston is arranged to displace in a first radial direction to displace the wedge plate in a second circumferential direction, opposite the first circumferential direction such that the inner and outer races are independently rotatable with respect to each other.

A wedge friction clutch with onboard enable and disable function, including: an axis of rotation; an inner race; an outer race; a wedge plate located between the inner and outer races in a radial direction; a first resilient element; and a piston. For a locked mode, the first resilient element is arranged to displace the wedge plate in a first circumferential direction to non-rotatably connect the inner and outer races. For a free wheel mode the piston is arranged to displace in a first radial direction to displace the wedge plate in a second circumferential direction, opposite the first circumferential direction such that the inner and outer races are independently rotatable with respect to each other.

A hydraulic system for operating an automatic transmission for motor vehicles includes a hydraulic actuator for operating a clutch and a stop valve, whereas the actuator has a pressurizable actuating pressure chamber, which can be closed in a pressure-tight manner by means of the stop valve, such that the clutch pressure is maintained independent of the other pressures of the hydraulic system. The stop valve includes a closure device that is movable by means of a hydraulic control pressure (p_S) into a closed position, in which an actuating pressure chamber port, and thus the actuating pressure chamber, is closed by means of the closure device. The closure device is movable into an open position at least by means of the force of a spring, in which the actuating pressure chamber port is opened. Thereby, the stop valve features a shiftable locking device, by means of which the closure device can be fixed in the closed position.

A drive assembly receives rotational power from an input shaft rotatable about a rotation axis. The drive assembly includes a drive housing to which is mounted a wheel bearing support of a wheel mount that is configured to rotate about the rotation axis on a wheel bearing assembly. A planetary set is coupled between the input shaft and the wheel mount to selectably cause rotation of the wheel mount. The planetary set substantially fits within axial borders of the wheel bearing support and within an inner radial dimension of the wheel bearing support.

A drive assembly receives rotational power from an input shaft rotatable about a rotation axis. The drive assembly includes a drive housing to which is mounted a wheel bearing support of a wheel mount that is configured to rotate about the rotation axis on a wheel bearing assembly. A planetary set is coupled between the input shaft and the wheel mount to selectably cause rotation of the wheel mount. The planetary set substantially fits within axial borders of the wheel bearing support and within an inner radial dimension of the wheel bearing support.

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 dual clutch transmission includes an input shaft and a first clutch, which has a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuating piston. The transmission has a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuating piston. The transmission includes a first partial transmission having a first partial transmission input shaft, and a second partial transmission having a second partial transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are non-rotationally connected to one another. The first output disc carrier is non-rotationally connected to the first partial transmission input shaft. The second output disc carrier is non-rotationally connected to the second partial transmission input shaft. The second partial transmission input shaft is arranged coaxially and radially surrounding the first partial transmission input shaft.