A power unit includes at least one drive source that outputs rotational power to a drive target other than pumps; a first pump rotationally driven by the rotational power of the drive source; a second pump rotationally driven by the rotational power of the drive source, the second pump being different form the first pump; and a power transmission structure that transmits the rotational power of the drive source to the first and second pumps. The power transmission structure includes transmission components and transmits the rotational power to the first pump through one of the transmission components and to the second pump through another of the transmission components.

A hydraulic system for an automatic transmission of a motor vehicle. A high pressure circuit in which a pressure accumulator, at least one clutch as well as gear selectors and at least one hydraulic pump are arranged, which can be controlled by an electronic control unit. The pressure accumulator can be connected to a hydraulic positioning cylinder via at least one hydraulic path, wherein a control valve that can be controlled by the control unit is arranged upstream thereof, with which a hydraulic pressure at the hydraulic positioning cylinder can be adjusted, and which control valve can be moved between two through-flow positions in order to move a piston in opposing piston strokes via opposing piston travel paths as well as piston speeds in the hydraulic positioning cylinder.

A hydraulic system (1) for electro-hydraulically pressing and/or moving a first (8) and a second (9) set of disks of a CVT transmission (10) is provided. The hydraulic system (1) includes two electrically driven hydraulic pumps (4, 5). In order to reduce energy consumption during operation of the hydraulic system, the hydraulic pumps (4, 5) are in the form of self-inhibiting hydraulic pumps (4, 5) which, when a hydraulic pressure is applied and the associated electric drive is switched off, substantially maintain the applied hydraulic pressure as a result of a static friction and a residual moment of the associated electric drive.

A control device controls a lockup clutch interposed between an engine and an automatic transmission mechanism of a vehicle. The control device includes a control part supplying hydraulic pressure to the lockup clutch and controlling differential pressure of the lockup clutch. The control part supplies the hydraulic pressure to the lockup clutch so that the differential pressure is lower than a reference differential pressure in a disengaged state of the lockup clutch. In a case of shifting the lockup clutch from the disengaged state to an engaged state, the control part supplies the hydraulic pressure to the lockup clutch so that the differential pressure increases as a filling ratio of an oil passage of the lockup clutch decreases. The reference differential pressure is a lower limit of the differential pressure that increases a slip ratio of the lockup clutch or reduces a slip amount of the lockup clutch.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. At least one of the first and second hydraulic units has variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft and the rotatable component of the second hydraulic unit. One of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.

A motor vehicle transmission that includes an input shaft (AN), an output shaft (AB), a power take-off (1) and a first intermediate wall (5). The power take-off (1) has a power take-off gearwheel (1A). The power take-off gearwheel (1A) is arranged coaxially with the input shaft (AN) and is rotatably supported by the first intermediate wall (5).

A method for actuating a hydraulic system of a transmission comprising a variable displacement hydraulic pump and a pilot-controllable system pressure valve, the method including, in order to determine a pump characteristic curve of the hydraulic pump, initially transferring the hydraulic system into a defined operating condition range in which the volumetric output flow, routed via the system pressure valve and applied at the system pressure valve by the hydraulic pump, is greater or less than a hydraulic fluid flow out of the hydraulic system. The method further includes pilot-controlling the system pressure valve to set a defined pressure level of the system pressure. The method additionally includes reducing or increasing the volumetric output flow while monitoring the system pressure, and determining a volumetric output flow corresponding to the hydraulic fluid flow of the hydraulic system with a certain deviation of a current system pressure from the defined system pressure.

A torque transmission device for a vehicle including at least one motor, the torque transmission device including a first clutch, a second clutch and a transmission member. A first transmission mechanism is provided between the first clutch and the transmission member, and a second transmission mechanism is provided between the second clutch and the transmission member. A connection element arranged to permit or interrupt the mutual rotational drive between the first output element of the first clutch and the transmission member, by means of the first transmission mechanism.

Systems, methods, and apparatuses for operating a machine using energy stored in a compressed gas are disclosed. Energy stored in the compressed gas may be used to pressurize a fluid, such as transmission fluid, and the pressurized fluid may be used to effectuate an operation of the machine, such as a transmission, and the operation of the machine may involve shifting of the transmission. The gas may be compressed by a first fluid using a second fluid, and the two fluids are be prevented from being mixed together.

Methods and systems for a transmission are provided herein. In one example, a hydraulic system is provided that includes a boost pump, a relief valve in fluidic communication with the boost pump and a reservoir, and a plurality of control valves in fluidic communication with the boost pump, positioned downstream of the relief valve, and in fluidic communication with a plurality of hydraulic devices. The hydraulic system further includes a controller designed to actively adjust a position of the relief valve based on an aggregate hydraulic pressure demand of the plurality of hydraulic devices to alter a boost pressure of a hydraulic fluid supplied to the plurality of control valves.