A viscous fluid shear device that includes a floating wiper. The wiper defines at least one fluid channel on a surface of the wiper that faces a circumferentially extending surface on a rotor. Each fluid channel has a first portion, which is formed with a first cross-sectional area, and a second portion that is formed with a second, smaller cross-sectional area. Each of the first and second cross-sectional areas is defined by first and second planes, respectively, that extend through the central axis. The second plane is spaced circumferentially apart from the first plane in the predetermined rotational direction.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

A viscous clutch includes a shaft, a rotor attached to the shaft, a housing located adjacent to the rotor, a working chamber defined between the rotor and the housing, a reservoir used to store a shear fluid, a valve assembly, an electromagnetic coil, and a flux insert in the housing. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the rotor and the housing. The valve assembly regulates flow of the shear fluid between the reservoir and the working chamber, and includes an armature. Selective energization of the electromagnetic coil governs actuation of the valve assembly. A flux circuit is provided that extends from the electromagnetic coil to the armature and back to the electromagnetic coil. The flux circuit passes through the flux insert and through the shaft, and the flux circuit crosses a radial air gap between the flux insert and the armature.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

The invention relates to an auxiliary drive device (1) comprising an electric motor (10, 11); and a mechanical clutch, wherein the electric motor (10, 11) and the mechanical clutch have the same axis of rotation (R), the mechanical clutch is designed as a fluid-friction clutch (20), and the electric motor (10, 11) and the fluid-friction clutch (20) are mechanically connected to one another.

A viscous fluid shear device that includes a floating wiper. The wiper defines at least one fluid channel on a surface of the wiper that faces a circumferentially extending surface on a rotor. Each fluid channel has a first portion, which is formed with a first cross-sectional area, and a second portion that is formed with a second, smaller cross-sectional area. Each of the first and second cross-sectional areas is defined by first and second planes, respectively, that extend through the central axis. The second plane is spaced circumferentially apart from the first plane in the predetermined rotational direction.

A viscous clutch (20; 20) includes a rotor (26), a housing (24) that at least partially surrounds the rotor, a center shaft (22) rotationally fixed to the housing, a mounting disk (30) rotationally fixed to the rotor, a working chamber (38) defined between the rotor and the housing, a reservoir (36) for holding a supply of shear fluid, an electromagnet (34), a valve assembly (32) to selectively control flow of the shear fluid between the reservoir and the working chamber, and a flux guide (54) operatively positioned between the electromagnet and the armature. At least a portion of the mounting disk extends outside the housing. The valve assembly including an armature (32-3) that is selectively movable in response to magnetic flux generated by the electromagnet, and the magnetic flux is transmitted between the armature and the electromagnet along a flux circuit. The flux guide extends through the mounting disk.

A valve system (44) for reducing morning sickness effects in a viscous clutch (20) having a reservoir (38) with a bore (46-1) includes a valve element (44-1), a counterweight portion (44-2), a pivot (44-3), and a biasing member (44-4). The pivot is located in between the valve element and the counterweight portion, and the valve element and the counterweight portion are configured to commonly move about the pivot between open and closed positions. The biasing member is configured to bias the valve element to cover the bore in the closed position by default. The counterweight portion is configured to counteract the biasing member under centrifugal loading such that the valve element at least partially uncovers the bore in the open position.

A clutch device for a clutch system has an input member that rotates at a first speed. A friction drive system is disposed between the input member and an output member. The clutch device is selectively movable by a fluid actuator assembly, between an engaged position in which the friction drive system drives the output member to rotate at the first speed, and a disengaged position in which a viscous drive system rotates the output member at a second speed slower than the first speed. A variable viscous fluid supply assembly includes a viscous fluid storage chamber, a valve, and a valve actuator that selectively drives the valve to move between an open position and a closed position to control an amount of viscous fluid available to the viscous drive system, thereby varying the second speed.

A system and method of anchoring a bimetal coil member on a viscous clutch fan drive. An adjustable channeled retainer member together with a silicone or silicone-type material is used to anchor the free end of the bimetal coil member.