Abstract: A viscous coupling has first planar plates which are held and spaced in a housing of the viscous coupling. Second slotted plates, each received and movably held between two first plates, are also positioned in the housing. The second plates (24) include slots (36) which start from the outer circumferential face (32) of the plate (24) and extend over a limited part of the radial extension of the annular plate (24). The slots (36) are each defined by edges (38, 39) which protrude from a planar face of the plate (24). Via the edges, the second plates come into contact with the adjoining first plates which are fixed so as to be spaced. The sector (40) formed between the circumferential face (32), two adjoining slots (36) and an imaginary circle (41) at the slot end (37) of the slots (36) is provided with an aperture (42) to discharge viscous fluid contained therein.

Abstract: A novel viscous coupling for transmitting rotary torque via a viscous fluid has first and second torque transmission members, a working chamber hermetically packed with a viscous fluid, and first and second plates alternately disposed in the working chamber. The transmission of rotary torque between the first and second transmission members is carried out via viscous resistance of the viscous fluid between the first and second plates. The aforesaid viscous coupling is characterized by providing with a multi-plate clutch to adjust transmission power of the rotary torque between at least one of the plates and the torque transmission members. The coupling includes an externally operable engaging means for fastening the multi-plate clutch by pressing clutch plates of the multi-plate clutch. Also, the coupling has passages for leading the viscous fluid to contact portions between the clutch plates and the plates.

Abstract: A power delivering apparatus employs a viscous coupling for limiting differential action performed by a front differential of an engine-powered vehicle. In the power delivering apparatus, since at least one of rotary members of the viscous coupling is directly supported by a stationary support member of the body of the vehicle, it is possible to support the viscous coupling of the power delivering apparatus in a firmer manner than in the prior art, thereby permitting the power delivering apparatus to remarkably reduce both of vibration and noise.

Abstract: A viscous coupling comprises first and second torque-transmitting members (1, 2) rotatable relative to each other, defining an operating chamber at least partially filled with a viscous fluid; a plurality of first plates (16) engaging and rotationally fast with the first torque-transmitting member; a plurality of second plates (17) interleaved with the first plates, and rotatably mounted on the second torque-transmitting member (2); clutch plates (18) engaging the second torque-transmitting member and disposed alternately with the second plates; a control member (9) operable to compress the clutch plates axially to clamp the second plates between them, and seals (14, 15) operable between the first torque-transmitting member and the control member and between the second torque-transmitting member and the control member, at sealing surfaces (9A, 2A) which are substantially of equal effective diameter to one another.