Abstract: An electromagnetic clutch according to the invention includes a first rotatable member having an axial end plate of magnetic material and a second rotatable member. The second rotatable member includes a drive shaft, and a hub mounted on an end of the shaft. An annular armature plate is disposed on an outer peripheral portion of the hub facing the axial end plate of the first rotatable member with an axial air gap therebetween. An electromagnetic device is disposed within the first rotatable member for attracting the armature plate to the axial end surface of the first rotatable member. The armature plate is elastically connected with the hub by a plurality of leaf springs. A self-return type temperature switch is fixedly disposed within the first rotatable member and closely placed to the axial end plate of the first rotatable member for controlling the energization of the electromagnetic device according to the temperature on the axial end plate.

Abstract: A thermal response type fluid fan coupling device which is constituted by a sealed chamber which is divided into an oil accumulating chamber and a torque transmission chamber, and which accommodates a driving disc, by a separating plate having an oil flow adjusting hole, in which a dam is provided in a circulated passage connecting the torque transmission chamber and the oil accumulating chamber, and a valve member for opening and closing the flow adjusting hole in accordance with change in ambient temperature is provided so as to control torque transmission from the driving side to the follower side by changing the effective oil contact area in a gap for transmitting torque between the driving disc and the case and the cover, wherein an idle oil accumulating chamber which is connected to an oil introducing gap which is connected to the torque transmission chamber is provided at the position outer than the dam in the radial direction, and oil introducing means for connecing the oil accummulating chamber and t

Abstract: A differential device using a fluid includes a differential case and a pair of sleeves which are rotatably supported by the differential case. Each of the outer end portions of the sleeves is connectable to one of a pair of rotary output shafts, while the inner end portions of the same are protruded into the case to face each other with a small clearance left therebetween. A chamber to be filled with a viscous liquid is defined between the case and the sleeves. A plurality of drive plates which are rotatable integrally with the case and a plurality of driven plates which are rotatable integrally with the sleeves are disposed in the chamber alternately with each other and in an overlapping manner. Guide rings are interposed between the nearby driven plates to position them at equally spaced locations.

Abstract: In a viscous fluid coupling which is essentially composed by one rotor, the other rotor, a first oil storage chamber and a valve, the one rotor fixed to an input member and the other rotor fixed to an output member are combined to form an operation chamber. The first oil storage chamber is formed between the other rotor and the output member, and the valve opens and closes a port of an oil passage which communicates the first oil storage chamber with the operation chamber under control of a temperature sensitive member attached to the output member. In this construction a case fixed to the output member covers a side surface opposite to the rotors. A second oil storage member is disposed in a position corresponding to the first oil storage chamber between one rotor and the case. With this arrangement, a so-called taking-around phenomenon which is present when the operation of the viscous fluid coupling resumes can be eliminated.

Abstract: When a pulse width modulated electrical signal is employed to operate an electro-mechanical device, such as a solenoid valve, in a transmission to produce a controlled fluid pressure whose level is proportional to the signal's duty cycle, proper operation at cold temperatures is ensured by varying the frequency of the pulse width modulated signal directly with the temperature of the transmission fluid. By decreasing the operating frequency when the transmission fluid is cold (at which time the fluid may thicken and become heavy since its viscosity will increase), the solenoid valve will be actuated slowly enough to effect flow control through the valve and adequate regulation of the fluid pressure.

Abstract: A fluid shear coupling apparatus is disclosed herein which includes a driving member comprising a rotor mounted to a shaft and defining several annular ridges and grooves. The apparatus further includes a driven member including a bearing housing mounted to the shaft, a cover secured about a perimetric flange with the bearing housing, and a plate secured to the cover and defining several annualr ridges and grooves positioned complementary with the ridges and grooves of the rotor. In the preferred embodiment, the plate, cover, bearing housing and rotor are as-formed structures.

Abstract: In an operation chamber 19 filled with silicone oil, there is provided a first resistance plate 21, which is spline-mated to the outer circumference of a first transmission shaft 3, and a second resistance plate 23, which is spline-mated to a second transmission shaft 9. These two resistance plates 21, 23 are clamped at both sides thereof by a clamp means formed from a pair of ring members 27, 29. The ring members 27, 29 are joined to a piston formed from the first transmission shaft 3, the sideplate 11, and a stopper ring 25. Then, when this piston moves in thrust and the clearance between the ring members 27, 29 shrinks, the blocks of the first resistance plate 21 and the second resistance plate 23 arranged side by side are clamped and abutted closely to produce a friction force at the resistance plates 21, 23.

Abstract: A vehicle driving system including a hydraulic clutch having a plurality of friction members which are adapted to be forced into engagement with each other by a hydraulic pressure applied to a piston in the clutch. A control unit is provided to detect a condition of heat generation in the hydraulic clutch and relieving the hydraulic pressure to the clutch or increasing the hydraulic pressure to the hydraulic clutch when the condition of heat generation is out of an allowable limit.

Abstract: The fluid friction clutch for the cooling fan of an internal combustion engine carries, on the front of its housing, a bimetallic element on the longitudinal ends of which flexible retaining tabs are formed. The retaining tabs are bent over towards the front and riveted with the front. The securing of the bimetallic element is especially durable.

Abstract: A viscous fan clutch having clutch and pump plates with interleaved lands to form the shear zone featuring an annular blocker ring and axial fluid feed passages radially inward of the blocker ring leading to the shear zone through lands partially or completely removed from the clutch plate to improve flow distribution into the shear zone.

Abstract: A fluid coupling device is disclosed of the type including a valve member (41) actuated by a valve shaft (39) extending through a cover (35), the position of the valve and valve shaft being controlled by a temperature responsive bimetal coil (43). The coil has a first end (47) attached to the valve shaft and a second end attached by means of a clip (53) to the cover. The valve shaft includes a pair of axially extending nubs (61) which are axially deformed into intimate engagement with the first end of the coil to prevent movement of the first end of the coil relative to the valve shaft. The second end of the coil includes a portion (55) parallel to the cover and a portion (57) parallel to the end of the coil. Each of the clip portions includes a projection (59), and the second end of the coil is projection resistance welded to the clip portion (57), and the clip portion (55) is projection resistance welded to the cover.

Abstract: A fluid friction clutch, suitable especially for a cooling fan of an internal combustion engine, has a shear gap of substantially serpentine form seen in axial longitudinal section, which is formed by concentric annular ribs. The ribs of the two parts which form the shear gap engage in each case in concentric annular grooves between radially adjacent ribs of the other part. The ribs have conical ring flanks with a flank angle preferably of 30.degree. and terminate in a flat end face perpendicular to the rotation axis. The groove bottom opposite to this end face has a rounded cross section and is spaced from the end face by a distance about equal to 1.2 to 1.4 times the width of the shear gap between opposed rib flanks. Because of this geometry, the fluid friction clutch has a very great torque transmission capacity with small dimensions and reacts very rapidly to variations of state.

Abstract: A viscous fluid coupling used as a cooling fan for automobile engines, having a power output member divided into two water chambers by a partition. The refluxing of water between the two chambers are controlled by a valve which opens the first hole of the partition by being associated with a bimetal that operates by detecting the temperature of the air passing through the radiator and opens the second hole of the partition by being associated with a thermostat that operates by detecting the temperature of the water in the water pump, thereby effecting the accurate control of the rotation speed of the fan.

Abstract: The fluid friction clutch, especially fan clutch, comprises for the temperature-dependent controlling of its shear fluid cycle a bimetallic element (35) which is to be displaced in its longitudinal direction for installation in a retaining fitting (37). A clip (63) fitted on to the retaining fitting (37) after the installation of the bimetallic element (35) blocks the path of introduction of the bimetallic element (35) and thus secures the bimetallic element (35) against unintentional release out of the retaining fitting (37).

Abstract: A fluid coupling device is disclosed of the type including a rotatable coupling assembly (73) including a housing member (75) and a cover member (77) which define a fluid chamber therebetween. A coupling member (71) is disposed in the fluid chamber and its forward surface and adjacent surface of the cover member (77) define a viscous shear space. The cover member (77) includes a plurality of cooling fins (85) disposed on the forward surface of the cover member. The coupling assembly (73) defines a maximum predetermined radius R. The cover member (77) and housing member (75) are joined at an annular outer urface (93) and an annular inner surface (97), these surfaces being disposed rearwardly of the shear space. The cover member (77) defines an annular inner surface (101) which is the outer periphery of the fluid chamber. The coupling member (71) includes an annular inner surface having a radius in the range of about 0.87 R to about 0.

Abstract: A liquid friction coupling, which preferably constitutes a differential arranged in the shaft line between two driven axles of a vehicle, consists of a rotatable housing (1), which is filled with a viscous liquid, a shaft (2), which protrudes into the housing (1), and a number of interdigitating blades (5, 6). The blades (5) of one set are non-rotatably connected to the housing (1) and the blades (6) of the other set are non-rotatably connected to the shaft (2). The shaft (2) includes a cavity (4), which serves to receive liquid from the housing (1) and contains a spring-loaded slider (8). In order to effect an automatic control of the torque which can be transmitted during the starting period, the slider in the cavity (4) of the shaft constitutes a sliding valve member (8), which cooperates with slots or the like, which are formed in the shaft and lead into the housing (1). The sliding valve member (8) is adjustable in dependence on a performance variable, preferably in dependence on temperature.

Abstract: A viscous fluid coupling especially used for driving the cooling fan of engines, changing the rotation speed of the fan smoothly according to the temperature. The smooth change of the rotation speed, that is, the smooth change of torque transmission by the coupling is performed by employing a valve device which has a slot for passing fluid and a specially shaped valve member movable to control the opening and closing of the slot so that the rate of increase of the opening area of the slot is smaller in a low temperature region than in a high temperature region.

Abstract: A viscous fan clutch employing flat wipers with angled edges secured on the inner annular periphery of the clutch body which scavage viscous fluid from the space between the inner diameter of the main body and the outer diameter of the clutch plate which controls the rate of discharge of pumping slots formed on the inside diameter of the body to optimize fluid flow from the working cavity to the storage cavity by way of a discrete intermediate cavity to reduce horsepower requirement when a low output speed during disengaged mode is desired or a faster rate of disengagement is required.

Abstract: A viscous fan coupling unit is controlled by a bimetallic strip. The bimetallic strip is subdivided by an elongate slot into two partial strips. The partial strips are interconnected by end portions of the bimetallic strip and by a cross-piece. The cross-piece acts on a control pin of the viscous fan coupling. This bimetallic stream reacts immediately on temperature changes of the air strip passing around the bimetallic strip. By the slot internal stresses are avoided such that the bimetallic strip can provide larger deflection paths and larger control forces in response to temperature changes.

Abstract: The temperature-dependently controllable fluid friction clutch comprises a temperature-control device for the shear fluid circulation, with a bimetallic element (35) held on an end wall of the housing (7) and coupled, through a pin (39) freely displaceably guided in a bore (37), with a valve (25, 27) of the temperature-control device. To seal the pin (39) in relation to the housing (7) on the part of the pin (39) issuing from the housing (7) there is set a sealing element (41) which rests under axial stress through a sealing flange (43) of substantially annular disc form on a sealing surface (45) extending transversely of the axis (1) of rotation. The sealing flange (43) has substantially the form of a relatively shallow or flat frusto-conical shell widening towards the sealing surface (45) and is stressed substantially only to flex elastically. In this way friction forces between the pin (39) and the bore (37) can be reduced, which improves the accuracy of the temperature control.

Abstract: A fluid coupling device is disclosed of the type including an input coupling member (11) rotatably disposed within an output coupling assembly (13). A portion of the output coupling assembly comprises a cover member (17) which cooperates with a housing member (15) to define an operating chamber (31). A valve plate (29) separates the operating chamber (31) from a fluid reservoir chamber (33) and defines a fill opening (41) to permit fluid flow from the reservoir chamber into the operating chamber. In a primary embodiment, the cover member (17) defines a radial passage (79) which is disposed to communicate fluid from the reservoir chamber (33) to the operating chamber (31).

Abstract: A temperature compensating fluid friction clutch is disclosed. The fluid friction clutch comprises a housing substantially filled with a viscous fluid, a shaft disposed within the housing, and mutually interengaging inner and outer plates connected to the shaft and housing for rotation about an axis within the housing. Spacers are located in the gaps between the plates, while the plates are axially displaceable so as to vary the size of the gaps. Temperature responsive elements are also provided to compensate for any reduction in the fluid viscosity when the temperature of the fluid rises. The temperature responsive elements, which may be in various forms, act to decrease the size of the gaps between the inner and outer plates when the temperature of the viscous fluid rises. In one embodiment, the temperature responsive elements comprise an expansion element connected to the inner and outer plates and which expands upon an increase in temperature.

Abstract: A viscous fluid transmission including a rotary casing adapted to receve a viscous fluid and a rotary element within the casing. The casing and the rotary element are connected respectively to two drive shafts. Means is provided for pumping the fluid from its normal position in the casing into a holding reservoir or other displaced zone so as to reduce the quantity of fluid in contact with the rotary element and hence the transmitted torque. Means is also provided for varying the pumping action to modify the quantity of fluid in the casing.

Abstract: A clutch control system includes an electronic control apparatus for controlling a clutch based on clutch control data stored through a learning process. The clutch control system has a sensor for measuring the temperature of lubricating oil in a gear transmission, a memory for storing a corrective clutch control value commensurate with the temperature of the lubricating oil, and an electronic control apparatus for correcting a learned value used to control the clutch with the corrective clutch control value obtained on the basis of the measured temperature of the lubricating oil.

Abstract: The fluid friction clutch comprises a clutch input part drivable about a rotation axis and a clutch output part rotatable coaxially in relation to the clutch input part. The clutch output part together with the clutch input part defines at least one shear gap. A cover which forms a cavity enclosing at least the region of the shear gap is filled partially with viscous fluid and otherwise with gas. The gas-filled volume of the cavity contains less than 18 percent of oxygen by volume, preferably not more than 5 percent of oxygen by volume, in order to preclude a chemical reaction of the viscous fluid with the oxygen under thermal overloading which limits the utility of the viscous fluid. To reduce the proportion of oxygen either the cavity is evacuated or it is filled with a substantially oxygen-free protective or noble gas.

Abstract: Disclosed is a fluid friction clutch having front and rear working gaps, which are connected to one another in a manner which provides more continuous and uniform distribution of the torque-transmitting viscous medium between the gaps. The clutch includes at least one bore through the drive disk which separates the front and rear working gaps. The bore is positioned in annular grooves which are provided in the drive disk at the same radial distance as the bore and which further include baffles positioned in the grooves to block the flow of fluid around the annular grooves and to promote flow through the bore. A similar groove/baffle arrangement is provided as a return means on the rear side of the drive disk near to the outer periphery.

Abstract: Disclosed is a fluid friction clutch which comprises an input shaft, a primary disk connected to the shaft, and a secondary drive part, i.e., the clutch housing. The primary disk rotates in a work chamber arranged in the clutch housing and includes a reserve chamber in its interior. A fluid stream, which circulates between the work chamber on the secondary side and the reserve chamber on the primary side, is controlled via a valve attached to the primary disk. The valve is actuated via a tappet arranged coaxially in the input shaft. The orifice of the valve is arranged on the end face of the primary disk, and the associated valve closure element is located in the interior of the reserve chamber. An overflow orifice is present on the circumference of the primary disk in conjunction with a baffle, whereby pumping of the fluid from the work chamber into the reserve chamber is achieved. This fluid friction clutch is used, preferably, as the fan drive means for a radiator in motor vehicles.

Abstract: The fluid friction coupling, which is suitable especially for a fan of an internal combustion engine, comprises a buffer chamber (39) which receives a part of the entire quantity of shear fluid contained in the coupling, through an inlet opening (43) placed beneath the shear fluid level (47), when the coupling is not in rotation. The received partial quantity lowers the liquid level in the shear gaps (23). In cold starting therefore the coupling transmits a reduced torque, which by reason of the consequently increased slip increases the pump effect of a pump device (37) and reduces the fan noise. The quantity of shear fluid contained in the buffer chamber (39) is delivered again to the shear fluid cycle of the coupling with time retardation through a constricted opening (45) when the coupling is in operation.

Abstract: A control clutch mechanism embodying a first aspect of the invention has an inner clutch part and an outer clutch part defining an annular space therebetween, with a viscous control unit and a frictional clutch unit being provided which consist of two sets of plates arranged in the annular space, each set of plates including plates alternately nonrotatively connected with one of the clutch parts, respectively. An axially movable annular piston is slidingly arranged in fluid-tight engagement between the viscous control unit and the frictional clutch unit and a pressure plate is located between the annular piston and the frictional clutch unit. A first stop is provided for the annular piston and a first spring acts between the piston and the pressure plate.

Abstract: The invention relates to a fluid-friction coupling for the cooling fan of an internal combustion engine. The torque transmission of the coupling is controlled in dependence upon the working temperature of the internal combustion engine. In order to suppress undesiredly high temperatures within the coupling at excessively high drive-input rotation speed, the torque transmission and thus the power loss are reduced when the working temperature of the coupling rises.

Abstract: Disclosed is a fluid friction clutch, wherein the force is transmitted from the driving to the driven member by means of the shear forces of a viscous medium located in gaps between the working surfaces of the driving and the driven sides. The transmittable force may be regulated by means of the degree of filling of the gap with the viscous medium as a function of external parameters. A fluid friction clutch of this type is characterized in that the drive and the driven members are elements of an at least three-member planetary transmission, wherein the individual elements of the planetary transmission engage each other through gaps, which in turn serve to receive the viscous medium, thereby effecting the transmittal of the force. It is possible with this clutch to obtain selected gear ratios between the driving and the driven members, in particular stepping up to higher speeds, even though the force is transmitted by fluid friction only.

Abstract: A fluid shear coupling apparatus includes a driving member comprising a rotor mounted to a shaft and defining several annular ridges and grooves. A driven member including a bearing housing is mounted to the shaft. A cover secured at the perimeter to the bearing housing has a disc-shaped portion defining several annular ridges and grooves positioned complementary with the ridges and grooves of the rotor. A shear fluid therebetween provides variable coupling according to the proportion of fluid in the reservoir vis a vis the working chamber defined by the complementary grooves and ridges. A temperature responsive valve cooperates with a modulation ramp encasing the valve end to provide a fluid control orifice which varies in size and radial location in response to temperature, thereby providing temperature modulation of the amount of shear fluid in the working chamber, and consequently, the degree of coupling.

Abstract: The temperature-controlled fluid friction clutch, suitable especially for a cooling fan, comprises a rotor which is arranged in a housing, rotatably in relation to the housing, forming at least one shear gap for the viscous fluid transmitting the torque. A scraper conveys the viscous fluid according to the dynamic pressure principle out of a working chamber containing the rotor into a reservoir chamber. The scraper is connected with the housing and lied radially opposite to the external circumference of the rotor, forming a scraper gap. The housing consists of a material the coefficient of thermal expansion of which is greater than that of the material of the rotor. In this way the scraper gap is enlarged with rising temperature, whereby the pump power of the scraper is reduced with rising temperature. The clutch unites good cold-start behavior with low temperature-actuation hysteresis in the operationally hot condition.

Abstract: Disclosed is a method and apparatus for controlling the output speed of a fluid friction clutch. The fluid friction clutch comprises a work chamber, in which a drive disk rotates, and a reservoir. A valve controls the circulation of a viscous medium between the work chamber and the reservoir. The output rotational speed is thus dependent on the filling ratio of the work chamber. The valve is actuated as a function of at least one control parameter by means of a stepping motor connected with the clutch. The control parameter is preferably the temperature of the cooling medium of an internal combustion engine. The rotational output of the stepping motor is converted to a linear motion to actuate the valve lever by means of a spindle drive.

Abstract: A fluid coupling device is provided of the type including an input coupling member (11) and an output coupling assembly (13). The unit includes a fluid operating chamber (33) and a fluid reservoir chamber (37), and a valve means (55) is included to control the flow of fluid between the chambers. The valve means (55) includes an elongated valve element (57) which is moved axially in response to energization of an electromagnetic coil (75). The valve element (57) includes a control portion (71) which is oriented at approximately a right angle relative to the valve element (57). The flow control portion is in engagement with a cylindrical surface (51) which defines the valve port (53), such that axial movement of the valve element results in sliding engagement between the control portion (71) and surface (51) to cover and uncover the valve port (53).

Abstract: An improved fluid coupling device is disclosed of the type including modulating valving. The coupling device includes an input coupling member (11) and an output coupling member (13) which cooperate to define a plurality of annular lands (57 and 59). The input member defines a rearward surface (61) and the output member defines an adjacent surface (63), thus forming a bottom end clearance within the coupling. The input coupling member further defines an annular transverse surface (71) and a cylindrical surface (73) which cooperate to define an annular recess (75). As the air temperature is increasing, and the operating chamber (33) is being filled with fluid, the annular recess (75) prevents the bottom end clearance from filling with viscous fluid in a way which results in an undesirably rapid rate of increase of the speed of the output coupling member (13).

Abstract: A viscous fan clutch which employs a dynamic blocker ring positioned inside of the clutch between the pump plate and the clutch plate in such a manner that the fluid flow path is directed and not left to chance. The blocker ring, in effect, hydraulically separates the drive portion of the clutch from the pump and viscous fluid storage portion. The divider ring due to its location will provide support outboard of the bearing providing optimized durability.

Abstract: Disclosed is a fluid friction clutch controlled as a function of temperature and/or rotation speed, comprising a driving primary member comprising a first reservoir chamber and an overflow orifice, wherein the primary member further comprises a device, responsive to the rotation speed of the primary member, for controlling the flow of a working fluid through the overflow orifice; a driven secondary member surrounding the primary member and optionally comprising a partition which defines a second reservoir chamber; a working chamber disposed between the primary and secondary members, optionally comprising pump means for controlling the flow of working fluid from the working chamber to the second reservoir, and an optional valve, located in the partition and being responsive to temperature, for controlling the flow of working fluid between the second reservoir chamber and the working chamber.

Abstract: A viscous fluid coupling device for controlling the transmission of an outpt torque in response to the ambient temperature of the device. The coupling device includes a valve plate for successively effecting first, second and third operational modes to maintain the output torque transmission respectively at low, medium and high levels. The valve plate is provided with a slot which is arranged to effect a fourth operational mode between the second and third operational modes thereby to reliably effect the second operational mode in response to a drop in the ambient temperature of the device.

Abstract: A fluid friction clutch is provided having an intermediate wall, disposed in a housing and separating the clutch fluid supply or storage space and the clutch fluid working space, with a plurality of overflow openings therein at circumferentially spaced locations. The clutch fluid primarily enters the working space from the storage space through a controllable supply inlet opening in the intermediate wall. The supply inlet is thermostatically controlled by a bi-metal element. A rotating clutch disk is provided in the working space, and at least one clutch fluid return bore is provided in the intermediate wall in the region adjacent the outer circumference of the clutch disk. These return bores provide return guidance for clutch fluid into the storage space.

Abstract: A fluid friction clutch is disclosed which has a working chamber formed by an output component in which a driving disk that is connected with an input component can rotate. For the adjustment of the degree of clutching, the working chamber can be filled by fluid supplied from a reservoir chamber developed as a pressure chamber and connected with the working chamber via a fluid connection, such as a pipe, a borehole, or similar means. This fluid connection is developed in such a way that, by means of admitting compressed air to the reservoir chamber, fluid can be delivered in a controlled manner from said reservoir chamber into the working chamber. A fluid friction clutch of this type has not movable mechanical valve parts, which is particularly advantageous when the compressed air is admitted to the reservoir chamber in surges, which would result in a rapid wear in the case of the known embodiments.

Abstract: A fluid coupling device is disclosed of the type including an input coupling member (11) and an output coupling member (13). A valve plate (31) separates the device into a fluid operating chamber (33) and a fluid reservoir chamber (35). In a preferred embodiment, the valve plate defines an inlet port (53) and a discharge port (59), which are conventional, and, in accordance with the invention, a discharge port (55) is disposed adjacent a pumping element (57). Attached to the valve plate is a temperature-responsive bimetallic strip (63) having a closed position when the fluid temperature is below a predetermined maximum, such that the device operates in the engaged mode. When the fluid temperature rises above the predetermined maximum, the bimetallic strip (63) opens, permitting additional discharge flow through the port (55), causing the device to operate in the disengaged mode, and preventing overheating of the fluid and damage to the coupling device.

Abstract: The disclosure concerns a hydrodynamic control coupling with a primary drive vane wheel and a secondary driven vane wheel which together define a toroidal working chamber. Each vane wheel carries an array of vanes on its interior which extend toward the vanes of the other vane wheel. The vanes of the vane wheels are inclinded with respect to the axis of the coupling, yet each is oriented parallel to a respective radius of the coupling. Furthermore, the vanes on each of the vane wheels are inclined to extend toward the vanes on the other wheel. There is a working fluid inlet to the working chamber. A working fluid outlet from the working chamber is through the secondary, driven vane wheel and is via a plurality of bores extending tangentially toward the axis of the coupling. An overflow valve communicates with the outlet from the working chamber. Upon the rotary speed of the primary vane wheel increasing rapidly, the overflow valve reacts by opening more widely, reducing the filling level in the coupling.

Abstract: The viscous coupling for a cooling air fan, especially of an internal combustion engine, comprises a drive shaft rotatable about a rotation axis, on which a housing is rotatably mounted. A partition divides the housing into a reservoir for a viscous shear fluid and a working chamber. In the working chamber there is arranged a rotor non-rotatably held on the drive shaft. The rotor together with the housing or its partition defines at least one shear gap. A controllable valve device connecting the reservoir with the working chamber controls the inflow of the shear fluid from the reservoir into the working chamber, especially in dependence upon temperature. Adjoining the partition the working chamber possesses in the region of the external circumference of the rotor an annular space formed at least partly by the rotor. The partition contains at least one over-flow opening for the shear fluid, opening into the annular space.

Abstract: A viscous fan clutch (10) is typically employed in a fan drive mechanism within a truck or automobile. A shaft (12) driven by the engine, rotates a clutch member (24) within the fan drive. The clutch member is arranged for fluid engagement with a body member (42) for the transmission of torque thereto when the fluid is disposed in an operating chamber (70) defined by complimentary shear surfaces (30 and 56) in the clutch and body members. During relative rotation between the two members, fluid is pumped from the operating chamber to a storage chamber (76) through a return passage (111). Fluid is returned to the operating chamber via bleed ports (118). The return passage and bleed ports are selectively restricted by an electromagnetically controlled valve (112) which taps the kinetic energy of the rotating members. A control system (132) senses vehicle coolant temperature and actuates the valve as a function thereof.

Abstract: A temperature responsive coupling device for driving a cooling fan of an internal combustion engine includes a shaft rotatably mounted in an output coupling member coaxially with an input coupling member which is operatively coupled to the output coupling member by means of a coupling. A bimetal spring is operatively connected to one end of the shaft and a valve plate is connected to the opposite end of the shaft for controlling the flow of fluid within the fluid coupling. The shaft is supported in the output coupling member by means of a sealed bearing in order to decrease the sliding torque produced by the rotation of the shaft. A cover plate is positioned in front of the sealed bearing to protect the bearing from moisture and openings are operatively associated with the cover plate to allow any moisture which might have entered between the cover plate and the bearing to be expelled by centrifugal force.

Abstract: A protective clutch wherein a switching ring having an inner bore in the shape of a frustum is axially actuated to control a radially extending actuating pin which operates to place a control ring into and out of rotative engagement with one of a driven and driving member of the clutch. The control ring contains recesses within which torque transmitting balls of the clutch may move when the control ring is in angular alignment therewith to disengage the clutch with angular unalignment of the control ring operating to bring the torque transmitting balls back into torque transmitting position.

Abstract: A fluid coupling device (15) is disclosed of the type including an output coupling assembly (67) and an input coupling member (81) with a shear space (90) disposed therebetween. The coupling device includes a valve assembly (117) to control the flow of fluid from a reservoir chamber (99) into the shear space (90). Movement of the valve assembly (117) is in response to variations in air pressure in a pressure chamber (59), tending to bias a piston (57) and shaft (93) in opposition to the force of a spring (113). Axial movement of the shaft (93) is translated into movement of a valve arm (127) in a plane parallel to the plane of a fluid port (119) by means of a valve actuation mechanism (109). In the subject embodiment, axial movement of a valve actuation piston (111) results in rotation of the valve assembly (117) about the axis of rotation of the device (15) for improved valve action in a remote sensing type of fluid coupling device.

Abstract: An automatic clutch control system for controlling a vehicle master clutch (14) drivingly interposed a throttle controlled engine (12) and a change gear transmission (10) having a clutch protection portion (70) to prevent the clutch from destructively overheating due to excessive slipping is provided. The clutch protection portion (70) includes a device for maintaining a variable parameter simulating clutch operating temperature (110) and devices (104 and 116) for causing said variable parameter to be increased and decreased, respectively, at first and second rates selected to simulate clutch heating and cooling rates, respectively. A signal generating device (126) is responsive to the simulated value exceeding a predetermined limit to generate a clutch protection output singal (84) effective to cause the clutch to be operated in a non-slipping, preferably fully engaged, mode of operation.

Abstract: A viscous fluid coupling including an input member having a disc-shaped rotor, an output member rotatable with respect to the input member and having a housing encircling the rotor, a partition wall in the housing for dividing the inside of the housing into an oil chamber and a working chamber. The rotor is located in the working chamber and a labyrinth device is provided between the rotor and the housing for making it possible to transfer rotation of the rotor to the housing under a supply of viscous oil to the labyrinth device. Perforations are formed in the partition wall for establishing a communication between the oil chamber and the working chamber so that the viscous oil can be supplied from the oil chamber to the working chamber. Oil expelling passages are also provided for connecting radially outward portions of the oil and working chambers so that the viscous oil in the working chamber is expelled to the oil chamber under pumping action of the rotor when the rotor is rotated.