1. Field of the Invention
The present invention relates to torque coupling devices in general, and more particularly to a hydraulically actuated torque coupling device provided for transmitting a drive torque at from an input to at least one output.
2. Description of the Prior Art
Conventionally, torque coupling devices well known in the prior art, and are used in various applications, such as vehicular drivetrains, to limit slip and transfer drive torque between a pair of rotary members. In all-wheel drive applications, torque coupling devices are used to automatically control the drive torque transferred from a driven member to a non-driven member in response to speed differentiation therebetween. In limited slip applications, couplings are used in association with a differential to automatically limit slip and bias the torque distribution between a pair of rotary members.
Such torque coupling devices conventionally use a frictional clutch between the rotary members. The frictional clutch may be selectively actuated by various hydraulic actuator assemblies, which are constructed of elements disposed inside a casing. The hydraulic actuator assemblies internal to the casing often include displacement pumps disposed inside the casing and actuated in response to a relative rotation between the differential case and the output shaft. The displacement pumps are usually in the form of internal gear pumps, such as gerotor pumps adapted to convert rotational work to hydraulic work. The hydraulic actuator assemblies further include a hydraulic piston member for frictionally loading the friction clutch.
While known torque coupling devices, including but not limited to those discussed above, have proven to be acceptable for various vehicular driveline applications, such devices are nevertheless susceptible to improvements that may enhance their performance and reduce cost. With this in mind, a need exists to develop improved torque coupling devices that advance the art.