Abstract: An electrohydraulic clutch includes a bidirectional electric motor, a hydraulic circuit and a multiple plate friction clutch pack. The bidirectional electric motor drives a ball screw through a gear reduction assembly. An electric brake on the motor output may be energized to inhibit its rotation. Alternatively, an anti-back drive wrap-spring assembly may be utilized on the motor output. The ball screw output bi-directionally translates a master piston of the hydraulic circuit which in turn advances and retracts an annular slave piston disposed adjacent the friction clutch pack. Hence, actuation of the electric motor displaces hydraulic fluid and compresses or relaxes the friction clutch pack, thereby transferring or inhibiting torque.

Abstract: A method and apparatus for a four-wheel drive motor vehicle provides improved cornering by disengaging drive torque to the inside rear wheel during significant steering maneuvers. The apparatus includes a primary front wheel drive motor vehicle driveline having a center differential which provides drive energy to the primary (front) driveline and secondary (rear) driveline and a rear axle assembly having a pair of normally engaged (active) clutches which provide drive energy to the respective rear wheels. A steering angle sensor detects angular displacement of the steering column or front (steering) wheels and an associated controller disengages the clutch associated with the rear wheel on the inside of the turn as determined by the steering angle sensor.

Abstract: An electrohydraulic clutch includes a bi-directional electric motor, a hydraulic circuit and a multiple plate friction clutch pack. The bi-directional electric motor drives a ball screw through a gear reduction assembly. The ball screw output translates a master piston of the hydraulic circuit which in turn advances and retracts an annular sleeve piston disposed adjacent the friction clutch pack. Hence, actuation of the electric motor displaces hydraulic fluid and compresses or relaxes the friction clutch pack, thereby transferring or inhibiting torque.

Abstract: A method and apparatus for a four-wheel drive motor vehicle provides improved cornering by disengaging drive torque to the inside rear wheel during significant steering maneuvers. The apparatus includes a primary front wheel drive motor vehicle driveline having a center differential which provides drive energy to the primary (front) driveline and secondary (rear) driveline and a rear axle assembly having a pair of normally engaged (active) clutches which provide drive energy to the respective rear wheels. A steering angle sensor detects angular displacement of the steering column or front (steering) wheels and an associated controller disengages the clutch associated with the rear wheel on the inside of the turn as determined by the steering angle sensor.

Abstract: A yaw damper for a front wheel drive vehicle provides torque transfer between the two non-driven wheels and generates a damping yaw moment in opposition to the current vehicle yaw condition. The yaw damper is passive and includes a mechanical clutch or fluid connection between the two non-driven wheels which transfer yaw correcting torque. The mechanical clutch includes first and second pluralities of interleaved friction disks which are coupled by shafts to respective non-driven wheels. A spring compresses the clutch pack and limits torque transfer between the shafts and wheels to a pre-selected maximum torque. In another embodiment, positive displacement pumps driven by each of the non-driven wheels are connected in series and transmit torque in proportion to the speed difference. In another embodiment, nested shafts include centrifugal clutches which transfer torque in proportion to vehicle speed and difference.

Abstract: A yaw damper for a front wheel drive vehicle provides torque transfer between the two non-driven wheels and generates a damping yaw moment in opposition to the current vehicle yaw condition. The yaw damper is passive and includes a mechanical clutch or fluid connection between the two non-driven wheels which transfer yaw correcting torque. The mechanical clutch includes first and second pluralities of interleaved friction disks which are coupled by shafts to respective non-driven wheels. A spring compresses the clutch pack and limits torque transfer between the shafts and wheels to a pre-selected maximum torque. In another embodiment, positive displacement pumps driven by each of the non-driven wheels are connected in series and transmit torque in proportion to the speed difference. A pressure relief valve limits the maximum pressure in the fluid lines and thus the maximum torque transfer.

Abstract: A hydraulic control for a power transmission has a regulator valve for controlling the hydraulic system pressure and a plurality of shift valves for controlling the automatic ratio change in the transmission. The shift valves are urged toward the higher ratio position by a governor pressure. The shift valves, except the 1-2 valve, are selectively subjected to separate modulated throttle valve pressures acting in opposition to the governor pressure and depending upon whether the respective shift valve is in the lower or higher ratio position. The modulated pressures are maintained at substantially zero for a portion of the throttle valve pressure range so that upshifting and downshifting will be sensitive to governor pressure and therefore vehicle speed only.The regulator valve is subject to a variable bias pressure which is proportional to throttle valve pressure.

Abstract: An oil level control system uses an available pressure source to operate a fluid motor which is integrally connected with a reciprocating fluid pump. The pump has an inlet passage disposed at the desired oil level in a primary reservoir. A pair of one-way valves cooperate with the pump to draw oil, above the desired level, from the primary reservoir and deliver the oil to a secondary reservoir. A restricted drain back passage permits the fluid to return to the primary reservoir to ensure that the desired level is maintained. The fluid motor is connected with an accumulator such that the initial portion of the stroke is operated by the pressure source of the pump stroke. The motor is driven by pressurized fluid in the accumulator.