A hybrid module includes a first, motor-side pre-assembly group and a second, transmission-side pre-assembly group. A separating clutch is arranged between the motor-side pre-assembly group and the transmission-side pre-assembly group, via which the pre-assembly groups can be connected in a torque-transmitting manner.

A hydraulic transformer clutch employs radial hydraulic piston assemblies with integrated electrohydraulic actuation. The hydraulic transformer clutch includes: an output shaft, an output disc affixed to the output shaft for rotation therewith, an input shaft, a rotatable housing affixed to one of the input shaft or the output shaft for rotation therewith, a plurality of hydraulic cylinders, and a plurality of working pistons. The hydraulic cylinders are operatively connected to the rotatable housing, and are spaced about the rotatable housing. Each working piston is slidably mounted within a corresponding hydraulic cylinder of the plurality of hydraulic cylinders, and is positioned to be selectively pushed, when actuated, to create a rigid connection between the input shaft and the output shaft. One or more actuator pistons are pushed by an electromagnet and create pressure that is distributed on working piston surfaces and generates active torque.

An actuating apparatus has a first and a second actuating element that delimit a pressure chamber. The actuating apparatus has a rotary decoupling bearing coupled via a compensation assembly to the second actuating element for joint movement along the spatial axis. The compensation assembly comprises a first ramp element which is supported axially on the second actuating element and is preloaded relative to the second actuating element by a first preloading apparatus for rotation about the spatial axis and a second ramp element coupled to the rotary decoupling bearing. An axial overall length of the compensation group along the spatial axis changes in the case of a rotation, of the first ramp element relative to the second actuating element. The compensation assembly has a blocking element and a blocking toothing system in blocking engagement with a counter-blocking toothing system of the first ramp element

An actuating apparatus has a first and a second actuating element that delimit a pressure chamber. The actuating apparatus has a rotary decoupling bearing coupled via a compensation assembly to the second actuating element for joint movement along the spatial axis. The compensation assembly comprises a first ramp element which is supported axially on the second actuating element and is preloaded relative to the second actuating element by a first preloading apparatus for rotation about the spatial axis and a second ramp element coupled to the rotary decoupling bearing. An axial overall length of the compensation group along the spatial axis changes in the case of a rotation, of the first ramp element relative to the second actuating element. The compensation assembly has a blocking element and a blocking toothing system in blocking engagement with a counter-blocking toothing system of the first ramp element

An actuating apparatus has a first and a second actuating element that delimit a pressure chamber. The actuating apparatus has a rotary decoupling bearing coupled via a compensation assembly to the second actuating element for joint movement along the spatial axis. The compensation assembly comprises a first ramp element which is supported axially on the second actuating element and is preloaded relative to the second actuating element by a first preloading apparatus for rotation about the spatial axis and a second ramp element coupled to the rotary decoupling bearing. An axial overall length of the compensation group along the spatial axis changes in the case of a rotation, of the first ramp element relative to the second actuating element. The compensation assembly has a blocking element and a blocking toothing system in blocking engagement with a counter-blocking toothing system of the first ramp element

An actuating apparatus has a first and a second actuating element that delimit a pressure chamber. The actuating apparatus has a rotary decoupling bearing coupled via a compensation assembly to the second actuating element for joint movement along the spatial axis. The compensation assembly comprises a first ramp element which is supported axially on the second actuating element and is preloaded relative to the second actuating element by a first preloading apparatus for rotation about the spatial axis and a second ramp element coupled to the rotary decoupling bearing. An axial overall length of the compensation group along the spatial axis changes in the case of a rotation, of the first ramp element relative to the second actuating element. The compensation assembly has a blocking element and a blocking toothing system in blocking engagement with a counter-blocking toothing system of the first ramp element

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 transmission includes a case, a clutch pack, a piston. The case defines a bore that transitions along a step from a first to a second diameter. The piston is disposed within the bore. The piston has first and second seals that engage the case along the first and second diameters, respectively. The piston defines a chamber that is encompassed by the piston, the case, the first seal, and the second seal. The piston is configured to engage a clutch pack when hydraulic fluid is channeled into the chamber.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, which are an input-side friction plate and an output-side friction plate, and an actuation system configured to engage the input-side friction plate with the output-side friction plate with a pushing force, the friction plates having a characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases. The device includes a controller configured to control the pushing force so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.