摘要 |
A differential gear unit includes a viscous coupling for restricting the differential rotation of output gears (27, 29), with the conneciton of one of the parts (31) of the viscous coupling to one output gear being by way of a releasable connecting device so that the viscous coupling can be brought out of operation when required, e.g. under vehicle braking. The connecting device comprises a sleeve (1), coupling members (11) movable radially in the sleeve (1) to engage, when in radially outermost positions, groove (35) for torque transmission, and an actuating member (2) movable axially within the sleeve and operable on the coupling members. The actuating member (2) is movable by an axially displaceable positioning member (87, 49) through the intermediary of latching balls (68, 48) which are themselves radially displaceable to hold the actuating member in position without continuous application of a high force. The positioning member may be movable mechanically, electro-magnetically, or by fluid pressure.
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