Viscous fan clutch with engage port lock

摘要

A clutch includes an input shaft with a clutch plate engaged with the input shaft to rotate in concert therewith. The clutch plate has an annular disk portion with a clutch plate set of lands and grooves. A housing includes a body supported on the input shaft by a bearing with a body set of lands and grooves mating with the clutch plate set of lands and grooves. A cover is included as part of the housing and engages with the body. A pump plate is captured between the cover and the body separating out a working chamber. The pump plate includes an engage port and a pump-out port positioned further radially outward in the pump plate than the engage port. A control arm normally closes the engage port and is rotatable to open the engage port. A slide-block is carried in a pocket of the cover with a spring biasing the slide-block toward engagement with the control arm. The slide-block locks the control arm against rotation when the clutch is inactive.