A hybrid drive system for a motor vehicle includes an input shaft, which introduces torques from an internal combustion engine into the hybrid drive system and which is mounted rotatably around an axis of rotation. An output shaft is arranged coaxially to the input shaft. The system also includes an electric machine having a stator and a rotor, and a hub non-rotatably connected to the rotor. The system further includes a wet clutch which has a first actuating piston. The hub is formed as a one-piece forged part and has a first running surface for the first actuating piston. The wet clutch is provided to non-rotatably connect the hub to the output shaft.

A method and a device for operating a drive train of a motor vehicle are provided. The drive train includes at least a first and a second shaft, a first clutch having at least one first friction surface pairing, and an electric drive, the first and the second shaft being coupleable to one another via the at least one first friction surface pairing, wherein for cooling the first clutch, a fluid is used via which a drag torque of the first clutch is influenced after the first clutch is disengaged, the method including: a) Rotating the first shaft and the second shaft when the first clutch is at least partially engaged; b) Disengaging the first clutch; c) Accelerating the first shaft by means of the electric drive and discharging the fluid from an area of the at least one first friction surface pairing;
wherein the drag torque of the first clutch is reduced by the accelerated discharge of the fluid.

A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

A hybrid drive system for a motor vehicle includes an input shaft, which introduces torques from an internal combustion engine into the hybrid drive system and which is mounted rotatably around an axis of rotation. An output shaft is arranged coaxially to the input shaft. The system also includes an electric machine having a stator and a rotor, and a hub non-rotatably connected to the rotor. The system further includes a wet clutch which has a first actuating piston. The hub is formed as a one-piece forged part and has a first running surface for the first actuating piston. The wet clutch is provided to non-rotatably connect the hub to the output shaft.

A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

A sprag clutch has an inner race, an outer race, and a radial cavity between the races. A plurality of sprags are disposed in the radial cavity, and each sprag is configured to rotate about an axis of rotation that is perpendicular to its longitudinal axis. A sprag cage retains each of the plurality of sprags at a uniform spacing within the radial cavity, and a plurality of actuators are positioned to exert or withdraw a force upon a corresponding sprag.

In an Oldham coupling, a first protruding part, protruding in a coaxial direction parallel to and extending in a first direction, is provided in one of first and second members, and the other of the first and second members includes a first notch part fitted to the first protruding part and slidable in the first direction along the first protruding part. A second notch part, extending in a second direction perpendicular to the first direction, is formed in one of second and third members, and the other of the second and third members includes a second protruding part fitted to the second notch part and slidable in the second direction along the second notch part. At least one of the first, second, and the third members has a heat dissipating structure including mutually separated concentric hollow cylinders of different diameters, connected by a bridge part.

A flywheel for use in an automobile between an engine and a clutch assembly is provided. The flywheel is a circular member having an engine side and an opposite clutch side. An aperture is formed in the circular member having an axis, and the aperture is used to operatively attach the flywheel to the engine. A plurality of clutch fins and/or grooves are formed on the clutch side adjacent the outer edge of the circular member and spaced radially about the axis of the aperture of the flywheel. The clutch fins have a face that is generally coplanar with the clutch side of the circular member. The fins and grooves work to cool the internal components of the engine. Optionally, a second set of grooves and fins may be formed on the engine side of the flywheel to further aid in cooling the clutch disc and other engine components.

An internal combustion engine including a cooling liquid circuit, which is connected to a cylinder head and an engine block of the internal combustion engine and which includes a cooling liquid pump. The cooling liquid pump includes a drive shaft and is capable of conveying cooling liquid in the cooling liquid circuit. Further, the internal combustion engine includes a Visco clutch. The Visco clutch is arranged for the drive by the internal combustion engine. The Visco clutch includes a clutch fluid for torque transmission. At the output side, the Visco clutch is connected to the drive shaft of the cooling liquid pump. The drive shaft of the cooling liquid pump include at least one heat pipe. The heat pipe is in heat exchange with the clutch fluid as a heat source and the cooling liquid as a heat sink.

An oil pressure supply system distributes lubrication for a dual clutch transmission and an includes a mechanical oil pump pumping oil stored in a sump while being driven by an engine; a line regulator valve directly supplying a lubrication flow rate to an input shaft and a counter shaft by controlling the oil pressure supplied from the mechanical oil pump and simultaneously supplying the lubrication flow rate to a gear train and clutch through another path; a line pressure control valve variably exhausting the lubrication oil pressure when the lubrication oil pressure supplied to the input shaft and the counter shaft is a predetermined value or more; an electric oil pump pumping the oil depending on a control of a transmission control unit; a first lubrication switch valve selectively blocking oil pressure supplied from the electric oil pump to the gear train and the clutch; and a second lubrication switch valve switching a flow path so that oil pressure supplied from the line regulator valve and the first lubrication switch valve is selectively supplied to the gear train and the clutch.