Abstract: A hydrodynamic friction clutch may include a rotatably mounted shaft, a drive disc non-rotatably fixed on the shaft, and an output body rotatably fixed on the shaft. The drive disc may include a radially extending annular transmission region for receiving a viscous fluid and via which the drive disc may be couplable to the output body for transmitting a torque, and an annular segment-shaped storage chamber for receiving the viscous fluid. The transmission region may be fluidically connected to the storage chamber via an inlet path and a drainage path. In the inlet path, a closable valve opening for controlling the quantity of the viscous fluid in the transmission region may be provided. The inlet path may include an annular segment-shaped communication passage, which may fluidically connect the storage chamber to the valve opening. The drainage path may fluidically connect to the inlet path at the valve opening.

Abstract: 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.

Abstract: A liquid friction clutch (1) having a housing (2, 3), a clutch disc (4)—rotatable relative to the housing (2, 3) and which is rotatably arranged on an end (5) of a shaft (6) which is mounted centrally within the housing (2, 3), which shaft (6) bears on its other end (8) a driveable active element (7). A working chamber (9) is positioned between the housing (2, 3) and the clutch disk (4). A storage chamber (10) is provided for the clutch fluid. A supply duct (11) leads from the storage chamber (10) to the working chamber (9). A stationary clutch part (13) relative to which the housing (2, 3) is rotatable, wherein a rotatably mounted pump element (14) is provided which, with the housing (2, 3), defines a shear gap (12).

Abstract: An engagement system (10) for a fluid-coupling device (9) may include a first engagement member (31) and a second engagement member (15) that is in operation with the first engagement member (31). A working chamber (33) is disposed between and at least partially defined by the first engagement member (31) and the second engagement member (15). The working chamber (33) has an inlet port (118) and an outlet port (120). A fluid reservoir (35) is fluidically-coupled to the working chamber (33). A scavenge valve (11) is coupled between the working chamber (33) and the fluid reservoir (35) and adjusts the fluid flow through the outlet port (120). An engagement system (10) for a fluid-coupling device (9) may in addition to or alternatively include a working chamber (33) that includes a working chamber inlet port (118) that is along an outer perimeter (126) of the first engagement member (31).

Abstract: The invention relates to a liquid friction clutch (1) having a housing (2, 3), having a clutch disk (4) which is rotatable relative to the housing (2, 3) and which is rotationally fixedly arranged on an end (5) of a shaft (6) which is mounted centrally within the housing (2, 3), which shaft (6) bears on its other end (8) a driveable active element (7); having a working chamber (9) between the housing (2, 3) and the clutch disk (4); having a storage chamber (10) for clutch fluid; having a supply duct (11) which leads from the storage chamber (10) to the working chamber (9); and having a stationary clutch part (13) relative to which the housing (2, 3) is rotatable, characterized by a supply pump element (14) which is rotatable relative to the housing (2, 3), which supply pump element is rotationally fixedly arranged on the shaft (6) and which supply pump element, with the housing (2, 3), defines a shear gap (12); and by a valve (17) which is arranged in the supply duct (11).

Abstract: A method for activating a clutch of a vehicle drive train. A controller of an electronic control unit generates an electrical desired-value signal corresponding to a desired pressure with which the clutch is to be acted upon. The control unit receives from a sensor an electrical actual-value signal which is to correspond to an actual pressure with which the clutch is acted upon. The sensor measures the pressure at a measurement location which is connected via a transfer link to an action location at which the clutch is acted upon with a clutch pressure. The actual-value signal passes through a transfer element having a delay property before it is delivered to the controller.

Abstract: A viscous fan drive having improved pumping efficiency from removing fluid from a fluid operating chamber to a fluid reservoir chamber is achieved by providing a wiper element that is located within the radial clearance between the clutch and the housing that effectively seals leakage paths leading (upstream) and trailing the wiper. The wiper element includes a radial tang that is positioned within a corresponding slot of the cover wall. The wiper element also has a pair of spaced apart arms extending from the radial tang portion each having a radial outer surface that has a similar radius as the cover wall and a radial inner surface has a similar radius as the clutch. The wiper element also preferably includes details designed to seal the radial inner surface to the outer periphery of the clutch during fan drive operation and a locating detail to aid in assembly.

Abstract: A fluid friction clutch with improved fluid pumping system. A scraping member is provided adjacent the clutch plate and has a duct which communicates with the reservoir chamber.

Abstract: The pump clutch is a device which transfers energy from its input shaft to the output shaft where a hydraulic gear pump is provided to enable the circulation of oil inside. The clutch input shaft is connected to the pressure production system; thus, the energy it requires to circulate the oil is provided. The amount of engagement between the clutch output shaft and the clutch input shaft is determined by the amount of oil circulating in the system. In turn, the amount of oil in the device is controlled by the control tap. With the clutch output shaft stabilized on the surface, we can control the circulation of the oil in the system with the control tap and the energy in the input shaft is thus transferred onto the stabilized surface through the output shaft thereby halting the rotation of the input shaft.

Abstract: A viscous fan drive having improved pumping efficiency from removing fluid from a fluid operating chamber to a fluid reservoir chamber is achieved by providing a wiper element that is located within the radial clearance between the clutch and the housing that effectively seals leakage paths leading (upstream) and trailing the wiper. The wiper element includes a radial tang that is positioned within a corresponding slot of the cover wall. The wiper element also has a pair of spaced apart arms extending from the radial tang portion each having a radial outer surface that has a similar radius as the cover wall and a radial inner surface has a similar radius as the clutch. The wiper element also preferably includes details designed to seal the radial inner surface to the outer periphery of the clutch during fan drive operation and a locating detail to aid in assembly.

Abstract: Accordingly, a control system for controlling a viscous clutch of a fan is provided. The control system includes a delta speed module that determines one of an over speed condition, an under speed condition, and a steady state condition based on a desired fan speed and an actual fan speed. A mode module determines a mode of the clutch based on the one of the over-speed condition, the under-speed condition, and the steady state condition, wherein the mode is one of a pump in mode, a pump out mode, and a closed loop mode. A valve control module that controls an operational state of the clutch valve based on the mode.

Abstract: A viscous fan drive having improved pumping efficiency from removing fluid from a fluid operating chamber to a fluid reservoir chamber is achieved by providing a wiper element that is located within the radial clearance between the clutch and the housing that effectively seals leakage paths leading (upstream) and trailing the wiper. The wiper element includes a radial tang that is positioned within a corresponding slot of the cover wall. The wiper element also has a pair of spaced apart arms extending from the radial tang portion each having a radial outer surface that has a similar radius as the cover wall and a radial inner surface has a similar radius as the clutch. The wiper element also preferably includes details designed to seal the radial inner surface to the outer periphery of the clutch during fan drive operation and a locating detail to aid in assembly.

Abstract: A viscous fan drive in which the output drive to the fan is controlled by the movement of viscous fluid from a fluid reservoir and into the operating and working chamber of the coupling during normal operation. The input-coupling assembly and cover member are formed with a unique combination of continuous and non-continuous radially extending lands and grooves designed to distribute the viscous fluid in a continuous film throughout the shear zone so as to maximize output fan speed at a given input speed. An armature-venting feature is designed to simplify the opening and closing of the valve disk in an electronic version of the viscous fan drive depending upon the desired operating condition.

Abstract: A viscous fluid clutch assembly used in automobiles, SUVs, and trucks minimizes flow back of the cooling fluid from the reservoir towards the working chamber of the clutch when the vehicle is at rest and avoids excessive fan noise, wasted power and fuel inefficiency when a cold automobile engine is started. The clutch utilizes a discharge channel extending from the periphery of the working chamber to the reservoir and a specially designed ball check valve at the entrance to the reservoir which is open or closed depending on operation of the vehicle. The ball check valve is fluidly connected to the working chamber of the fluid clutch by a preferred articulated discharge channel which starts at the working chamber of the fluid clutch and ends at the reservoir of the fluid clutch.

Abstract: A fluid friction clutch, in particular for a motor vehicle fan, having a rotatably mounted shaft wherein a reservoir for at least largely holding the fluid is provided radially inside an outer periphery of the drive body, and wherein at least one first flow path and at least one second flow path are provided, which are used to connect the reservoir to the coupling area, and wherein the drive body, at the outer periphery, has at least one flow resistance element which is arranged between the at least first flow path and the at least second flow path, and wherein furthermore there is a controllable device for closing and opening at least one of these flow paths.