Abstract: A differential device for transferring torque and rotation from an input shaft to a first output shaft and a second output shaft of a vehicle is provided. The differential device includes a carrier coupled to an input shaft, a first pump/motor coupled to the carrier and to the first output shaft, and a second pump/motor coupled to the carrier and to the second output shaft. The first pump/motor preferably functions to pump a hydraulic fluid upon a rotation of the first output shaft at a different speed than the carrier, and to rotate the first output shaft at a different speed than the carrier upon a sufficient pressurization of the hydraulic fluid. Similarly, the second pump/motor preferably functions to pump a hydraulic fluid upon a rotation of the second output shaft at a different speed than the carrier, and to rotate the second output shaft at a different speed than the carrier upon a sufficient pressurization of the hydraulic fluid.

Abstract: A four-wheel drive straddle-type all-terrain vehicle has a progressive limited-slip differential that functions as an open differential when the wheel speed differential is less than a predetermined threshold, or cutting point, and functions as a progressive limited-slip differential when the wheel speed differential exceeds the cutting point. The progressive limited-slip differential is able to transfer torque to the wheel with greater traction as a generally linear function of the wheel speed differential, meaning that the more one wheel slips with respect to the other, the more torque is transferred from the slipping wheel to the wheel with traction. The progressive limited-slip differential comprises a rotary shear pump that drives a piston against a pack of clutch plates. The force of the piston against the clutch pack locks the left and right axles together to provide optimal traction in slippery conditions.

Abstract: A hydraulic coupling for use in a vehicle drivetrain includes a housing and a pair of rotary members projecting therefrom. The hydraulic coupling also includes a hydraulic circuit defining a low-pressure portion wherein the hydraulic fluid is at a first, lower pressure and a high-pressure portion wherein the hydraulic fluid is in a second, elevated pressure relative to the first pressure. A hydraulic pump is operatively supported within the housing and located within the path of the hydraulic circuit between the low pressure and high-pressure portions. The hydraulic pump is operable to pump hydraulic fluid from the low-pressure portion to the high-pressure portion of the hydraulic circuit. In addition, a clutch is supported within the housing and located within the high-pressure portion of the hydraulic circuit. The clutch is actuable by hydraulic fluid that is pumped by the hydraulic pump at the second, elevated pressure to couple the pair of rotary members together.

Abstract: The invention relates to a speed difference dependent hydraulic coupling, consisting of rotating drive casing (2), a hydrostatic displacement machine (7) disposed therein, an output shaft (3) and a friction coupling (6) for connecting the output shaft (3) to the drive casing (2), wherein pressure is built up in a pressure chamber (26; 85) when a different speed emerges between the drive casing and the output shaft, said pressure impinging upon the friction clutch (6). In order to more accurately compensate for temperature-dependent fluctuations in viscosity, a throttle valve (33) is provided that is formed by a valve body (48) guided in a valve chamber (4) and supported on an element whose length (47) depends upon the temperature, said body having a control edge (51) cooperating with a control port (55) of the valve chamber (40), wherein the control port (55) produces the connection between the pressure chamber (26; 85) and the chamber with the lower pressure.

Abstract: An actuating device for a differential lock has a piston housing having a pressure chamber. An actuator piston is arranged in the pressure chamber of the piston housing. A hydraulic medium tank is provided. A pump conveys a hydraulic medium from the tank to one end of the actuator piston, wherein the actuator piston can move in the pressure chamber and acts on the lock when loaded by the hydraulic medium. One or more conduits connect the hydraulic medium tank and the pressure chamber to one another. The conduit has a temperature-dependent throttle element for adjusting a flow cross-section for the hydraulic medium based on the temperature of the hydraulic medium.

Abstract: A limited slip differential for an automotive vehicle includes a torque input differential pinion carrier, two differential side gears and a pair of torque output axle half shafts. The differential also includes at least one friction clutch assembly having first friction clutch plates connected driveably to the differential pinion carrier and second friction clutch plates connected driveably to one of the side gears. An annular pressure chamber is defined in the carrier. An annular piston is movably supported within the pressure chamber and adjacent the friction plates of the friction clutch assembly. The limited slip differential further includes a positive displacement gear pump having pumping elements defining high pressure and low pressure ports whereby pressure in the pressure chamber creates a force on the piston that engages a clutch assembly to effect a friction torque bias in the differential through the friction clutch assembly.

Abstract: A drive unit for driving the second driven axle of an all-wheel drive vehicle with a hydraulic coupling dependent on rotational-speed differences, comprising a driven case and two half shafts, which can each be connected to the latter by a friction clutch, the friction clutches being operatively connected to a hydraulic positive displacement machine that operates when a rotational-speed difference occurs between the case and the half shaft.

Abstract: A modular pressure relief valve assembly for a hydraulically actuated clutch pack or limited slip device in a limited slip differential or torque coupling device. The modular assembly is removably disposed in the differential case and is connected to a passageway leading to a limited slip device within the differential case to establish fluid communication there between.

Abstract: A pressure relief check valve for a hydraulically actuated clutch pack or limited slip device in a limited slip differential or torque coupling device. A ball seat is formed on the external surface of the differential case and is connected to a passageway leading to a limited slip device within the differential case to establish fluid communication there between. A ball rests on the valve seat and is retained thereon by a retainer and spring. The retainer is removable secured to the outer surface of the differential case and a coil spring is disposed between the ball and the retainer to bias the ball against the valve seat. When pressure within the differential case or limited slip device exceeds a predetermined pressure, the ball is lifted from the valve seat and fluid passes through the differential case to an exterior within the differential housing. When pressure in the differential case and limited slip device is less than the predetermined pressure, fluid is prevented from passing through the valve.

Abstract: A control valve of a hydraulic coupling controls pumping through a casing inlet port by a hydraulic pump and/or through a casing outlet port to control coupling between two rotary members such as by operation of a clutch. The casing is connected to one of the rotary members while a pumping component embodied by an impeller is connected to the other rotary member and meshed with an internal ring gear having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve includes a valve system through which pressurized hydraulic fluid selectively flows to control the coupling of the pair of rotary members. The instant invention provides a thin-plate check valve and pressure port stack which creates a hydraulic flow path for a gerotor pump and maintains pressure equalization about the gerotor pump.

Abstract: An all wheel drive mechanism has a powertrain including an engine, transmission, front drive differential, a rear drive transfer gearing and a selectively operable rear drive mechanism. The rear drive mechanism has a housing, driven by the transfer gearing through a drive shaft. A pair of selectively engageable clutches, which are operable to connect the rear wheels to the housing, are disposed in the housing. A pair of pumps are assembled in the housing to provide operating fluid for the clutches. Each pump has one member secured for rotation with the housing and another member secured for rotation with respective rear wheel drive axles. An inlet of the pumps is controlled by a solenoid operated valve which is energized in response to an anti-lock brake system and traction control system of the vehicle. When energized, the valve connects the pumps to a reservoir such that fluid in the reservoir can be pumped to the clutches to enforce engagement thereof resulting in a drive path to the rear wheels.

Abstract: The present invention relates generally to hydraulically actuated limited slip differentials. More particularly, the present invention relates to a hydraulic limited slip differential which utilizes a variable pressure relief check valve used to vary the maximum hydraulic pressure available within the differential case in a manner that the limited slip feature can be adjusted anywhere between a full “ON” and a full “OFF” configuration. Hydraulic fluid will not flow through the check valve until the hydraulic pressure within the case results in a reaction force larger than the check valve activation pressure, thus providing a maximum pressure limit in the hydraulic system. The activation pressure of the check valve can be selectively controlled by an actuator. The movement of the actuator corresponds to a change the retaining force of the check valve. Dynamic control of the system in response to vehicle operational parameters may also be performed.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A speed-sensitive, limited-slip, geared differential mechanism for transferring driving torque to each of two torque output shafts. Side gears located in a planetary gear carrier housing, one side gear being drivably connected to one pump member of a positive displacement pump and the planetary gear carrier being connected to another pump member. The pump is supplied with silicone fluid from a fluid reservoir. The pump creates a hydrostatic torque bias when differential motion of the side gears occurs as silicone fluid circulates through the pump.

Abstract: A flow control valve for regulating the flow across an orifice to eliminate the effects of viscosity changes throughout a range of temperatures for the hydraulic fluid. The valve includes a base with an orifice and a slide valve element that registers with the orifice and that is movable by a double, helix-wound, bimetallic spring. The bimetallic spring extends linearly in the direction of motion of the slide valve element so that its effective length will change a predictable amount for a given temperature change, thereby progressively changing the size of the orifice as the spring moves the slide valve element to which it is connected.

Abstract: A differential assembly is disclosed having a pair of hydraulic couplings installed in a differential casing and operably arranged to rotatively couple first and second rotary members to the differential casing. Each hydraulic coupling includes a clutch pack operatively connected between one of the rotary members and the casing, a hydraulic pump, and a fluid distribution system for delivering pumped fluid to a pressure chamber to actuate a piston for engaging the clutch pack and to a clutch chamber to cool the clutch pack.

Abstract: An axle case assembly is provided with a speed sensitive torque coupling mechanism used to transmit torque from the ring gear to a planetary differential assembly. The differential assembly provides torque transfer proportional to the speed difference between the ring gear sub-assembly and a planetary gear set sub-assembly, wherein the invention splits a differential case assembly into two primary pieces and a speed sensitive mechanism is installed between each piece. The mechanism is entirely contained inside an axle differential case assembly. An optional limited slip device may be provided for the differential gears. The torque transmission coupling assembly eliminates the need for a center differential in the transfer case, i.e. an interaxle differential, thereby reducing the driveline complexity and cost without requiring a separate torque coupling in the transfer case or in-line with the driveline.

Abstract: An automotive drive unit provided with a rotatably driveable input shaft and at least one output shaft driven by the input shaft, a hydraulic clutch responsive to differences in rotation between the input and output shafts and provided with a hydrostatic displacement pump which at the occurrence of such a difference generates pressure for reducing the difference. The pressure fluid is drawn by the pump from a stationary reservoir into a suction chamber by way of a suction tube. In order to minimize the structural complexity of the drive unit and to provide a precise and quickly responsive control, the suction chamber is limited by a wall integral with the housing of the drive unit, and the suction tube is provided with a selectively controllable valve.

Abstract: A pressure control system for a differential includes an input member and a pair of output members, a pump disposed to be driven in accordance with the difference between the speed of one of the output members and a reference, a chamber which is supplied by the pump, and at least one bleed passage from the chamber. A piston is responsive to hydraulic pressure in the chamber to operate a brake between the one output member and the reference. The bleed passage includes a plunger which is movable against a resilient bias in response to pressure in the chamber. Flow through the passage is blocked when the pressure on the plunger reaches a set pressure.

Abstract: A hydraulic coupling includes a clutch assembly operatively connecting two rotary members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The clutch assembly includes a multi-plate clutch pack alternately connected between the two rotary members within a clutch chamber. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system having a first flow path between a supply chamber and the hydraulic pump, a second flow path between the hydraulic pump and the piston chamber, and a third flow path between the hydraulic pump and the clutch chamber. The fluid delivered to the piston chamber controls engagement of the piston with the clutch pack for controlling actuation of the clutch assembly. Additionally, the fluid delivered to the clutch chamber is used to cool and lubricate the clutch pack.

Abstract: A hydraulically actuated limited slip differential which can be configured to be either speed and torque sensitive or speed sensitive. The differential includes a hydraulic pump mechanism comprising a plurality of fluid supply passages disposed in a side gear and in fluid communication with a cavity defined by the side gear and a piston. The hydraulic pump mechanism transfers fluid into the cavity in response to meshing rotation between the pinion gears and the side gears. Sufficiently high differentiation between the output shafts increases the pressure in the cavity to increase frictional pressure between a frictional clutch mechanism and the differential casing to provide braking action between the side gears and the differential casing. The angular relationship between the clutch surfaces of the clutch mechanism and the differential casing may be configured such that the side gear separating forces and hydraulic pressure act in either a reinforcing or opposing manner.

Abstract: A working oil receiving chamber 8 is provided with an expanding and contracting member 12. The expanding and contracting member 12 is comprised of an expansible and contractible bellows 2a made of metal, and a bottom portion 12b made of metal and for closing opposite open ends of the bellows portion 12a, so that the member 12 can expand as the pressure of the working oil in the working oil receiving chamber 8 is increased and can contract as the pressure is decreased. A slightly compressed gas is filled in the expanding and contracting member 12.

Abstract: A hydraulically actuated limited slip differential which transfers a predetermined amount of clutch torque each time the clutch mechanism is triggered. The differential includes a hydraulic pump mechanism comprising a plurality of fluid supply passages disposed in a side gear and in fluid communication with a cavity defined by the side gear and the clutch mechanism. The hydraulic pump mechanism transfers fluid into the cavity in response to meshing rotation between the pinion gears and the side gears. Sufficiently high differentiation between the output shafts increases the pressure in the cavity to trigger the frictional clutch mechanism with the differential casing to provide braking action between the side gears and the differential casing. The clutch mechanism includes a cone clutch element having a frusto-conical engagement surface which frictionally engages an insert having a complementary frusto-conical engagement surface.

Abstract: A vehicle drivetrain differential (22) driven by a rotary drive member (24) rotatively drives a pair of rotary members (26, 28) and includes a housing (30) for containing hydraulic fluid and in which a hydraulic coupling (32) is received. A casing (34) of the hydraulic coupling has a ring gear (44) rotatively driven by the rotary drive member (24). A planetary gear set (36) of the bevel gear type is located within the casing (34) and includes a pair of bevel gears (124, 126) having associated spline connections (128, 130) to the pair of rotary members (26, 28), and the planetary gear set also includes planet gears 132 that revolve with the casing 34 and are meshed with both bevel gears to provide a differential gear action. A fluid inlet 58 and an outlet port 78 of the casing are provided with a gerotor type pump (48) provides pumping of hydraulic fluid into and out of the casing.

Abstract: A speed sensitive limited slip differential having a sealed, self contained clutch actuator which expands and retracts as required to frictionally seat a clutch element against a surface of the differential casing. The clutch actuator comprises a housing portion and a piston portion which define two fluid chambers and a gerotor pump assembly contained therein for transferring fluid between the two fluid chambers. The gerotor pump assembly is splined to an output element to transfer fluid between the two chambers when sufficient differential rotation between the output element and the casing exists. The transfer of fluid between the two chambers results in the axial expansion of the actuator housing and the actuator piston to provide an axial force on a side gear to thereby frictionally seat the clutch element against a surface of the differential casing. The sealed, self contained feature allows the present limited slip differential to operate in a simple, reliable manner.

Abstract: A differential drive having a controllable locking device is loaded by a differential-speed-dependent actuating device. A rotatingly drivable differential carrier is supported in a drive housing and is provided with axle shaft bevel gears which are co-axially arranged therein and which are connectable by insertable axle shaft journals. A plurality of differential bevel gears are rotatably arranged on radial journals in the housing and each engage both axle shaft gears, with the axes of the journals of the differential bevel gears being positioned in a central plane of the differential carrier. A multi-plate coupling unit for locking purposes is arranged co-axially in the differential carrier relative to the central plane on a first side of the unit and with a pump unit for actuating purposes being arranged co-axially in the differential carrier relative to the central plane on a second side of the unit.

Abstract: The invention provides a hydromechanical system for limiting differential speed between first and second rotating members of a vehicle drivetrain subassembly. The hydromechanical system comprises a casing disposed within a housing of the subassembly which is rotatably coupled to the first rotating member of the drivetrain subassembly. Hydraulic fluid is supplied from a sump within the drivetrain subassembly housing to a reversible hydraulic pump disposed within the casing, wherein the reversible hydraulic pump pumps hydraulic fluid in response to relative rotation between the first and second rotating members. A piston assembly is disposed within the casing which includes a guide member, an actuating member and a chamber disposed therebetween, wherein the chamber receives the pumped hydraulic fluid.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A supplemental pressurized hydraulic supply (103) provides control of a hydraulic coupling (32a,32b,32c) that normally operates in response to differential rotation between a pair of rotary members (26,28) to provide actuation of a clutch (68) that couples the pair of rotary members. A rotary seal assembly (104) of the supply (103) feeds pressurized hydraulic fluid to the coupling to provide supplemental actuation of the clutch (68) that is normally actuated by hydraulic fluid from a hydraulic pump (48) that operates in response to the differential rotation between the pair of rotary members. In one embodiment, the hydraulic coupling (32a) also includes a differential gear set (36). A further embodiment of the hydraulic coupling (32b) includes a clutch (68) having a pair of clutch packs (69) that can be individually actuated by the supplement pressurized hydraulic fluid supply (103).

Abstract: A differential unit is disclosed which has a differential limiting function and which exhibits stable differential limiting characteristic even if the difference in the differential rotations is small. The differential unit has a differential case, pinion gears, side gears, a gear pump disposed between a left side gear and the differential case.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A differential unit having a speed-sensitive-type differential limiting function is capable of moderating the differential limiting force to maintain the controllability and stability of a vehicle. The differential unit according to the present invention includes a differential case to be rotated by drive force of an engine, a differential mechanism for distributing rotations of the differential case to a pair of output shafts, a frictional clutch for limiting the differential of the differential mechanism, a hydraulic actuator for clutching the frictional clutch, an oil pump which receives differential torque of the differential mechanism so as to be driven to operate the hydraulic actuator, control valves for introducing air to the oil suction portion of the oil pump, and a controller for opening or closing the control valve to correspond to a condition under which a vehicle is driven.

Abstract: The present invention is directed to an improved power transfer system for use in four-wheel drive vehicles having a transfer case equipped with a torque transfer arrangement that is operable for automatically controlling the drive torque delivered to the front and rear drivelines of the vehicle and establishing an on-demand four-wheel drive mode.

Abstract: A hydromechanical system for limiting differentiation between a first rotating member and a second rotating member in a drivetrain subassembly. The hydromechanical system comprises a clutch assembly for selectively coupling the first rotating member to rotate with the second rotating member and a hydraulically actuated piston assembly for applying force on the clutch assembly to actuate the clutch assembly in response to hydraulic pressure such that the first rotatable member is selectively coupled to rotate with the second rotatable member. A clutch actuating pump, including a reservoir, is provided for supplying hydraulic pressure to the piston assembly to actuate the piston assembly, wherein the clutch actuating pump communicates hydraulic fluid under pressure to the piston assembly in response to differential rotation between the first and second rotating members.

Abstract: The invention provides a hydromechanical system for limiting differential speed between first and second rotating members of a vehicle drivetrain subassembly. The hydromechanical system comprises a casing disposed within a housing of the subassembly which is rotatably coupled to the first rotating member of the drivetrain subassembly. Hydraulic fluid is supplied from a sump within the drivetrain subassembly housing to a reversible hydraulic pump disposed within the casing, wherein the reversible hydraulic pump pumps hydraulic fluid in response to relative rotation between the first and second rotating members. A piston assembly is disposed within the casing which includes a guide member, an actuating member and a chamber disposed therebetween, wherein the chamber receives the pumped hydraulic fluid.

Abstract: A hydraulic coupling (32,32a) includes a lock (204) for selectively preventing the level of torque transmitted from a coupling casing (34) to a pair of rotary members (26,28) from affecting torque transfer between the rotary members. The coupling (32) also includes an adjuster (216) for adjusting resistance of fluid flow from a hydraulic pump (48) through ports of the coupling to control coupling of the pair of rotary members (26,28) to each other. One embodiment of the coupling (32) operates in a supercharged pumping manner, while another embodiment of the coupling (32a) pumps the fluid through a clutch actuating piston (72) of the coupling.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A hydraulic coupling (32) includes a control valve (80) that controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control operation of a clutch (68) for coupling between two rotary members. The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes a by metallic valve element (82) mounted within a recess (98) to provide accurate temperature compensated control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: The specification discloses a transfer case for four-wheel-drive vehicles. In one embodiment, the transfer case includes a fluid coupling and rotation of an input shaft is transferred to a front drive shaft by a pair of opposed rotatable rings having interleaved fins. The interleaved fins provide fluid filled chambers and relative movement of the fins compresses the fluid and increases the ability of the fluid to transfer torque.

Abstract: A locking limited slip planetary differential for the transfer case of an all-wheel drive vehicle. First and second coaxially juxtaposed sun gears are mounted to first and second output shafts, respectively, for rotation therewith. A plurality of first planet gears are rotatably mounted on a carrier, each of which meshes with the first sun gear. A plurality of second planet gears is also rotatably mounted on the carrier. Each of the second planet gears meshes with the second sun gear and with an associated one of the first planet gears. A hydraulically actuated clutch pack is provided for selectively connecting the carrier to the first sun gear to limit relative rotation between the first output shaft and the second output shaft. The clutch pack is actuated by a swash plate pump mechanism provided on the first and second sun gears which supplies hydraulic fluid to the clutch pack when the first and second sun gears rotate relative to one another.

Abstract: A hydraulic coupling (32) includes a control valve (80) that controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members. The casing (34) is connected to one of the rotary members while an impeller (50) having between five and seven external teeth is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes a bimetallic valve element (82) that compensates for temperature changes and may also include a speed sensitive valve closure (104) for providing immediate coupling without delay above certain speeds of operation. Mounting of the bimetallic valve element (82) of control valve (80) within a recess (98) provides accurate control of the temperature compensation.

Abstract: The transmission includes a hydraulically operated actuator for selectively controlling a locking mechanism for a differential mechanism interconnecting a motion input shaft and at least two motion output shafts. The lubricant for the differential mechanism is supplied by a pump to an actuator for the lock device with the pump being driven from the motion input shaft. In one embodiment, the pump and the actuator are disposed in a support for the differential mechanism. In a second embodiment, the pump is mounted on the housing and is provided with a reciprocating piston driven by a rotatable cam mounted for rotation with the differential casing. The plunger is biased in one direction by a spring in such a manner that the plunger is driven for a suction stroke by the cam and for a delivery stroke by the spring.

Abstract: A differential includes a planet gear through which two shafts coupled to laterally spaced road wheels of a motor vehicle are interconnected. The planet gear has a rotatable shaft with a brake mechanism coupled thereto. A braking force produced by the brake mechanism is transmitted through the differential to the road wheels depending on the rotational speeds of the road wheels. The brake mechanism may include either a turbine for producing a resistive force upon rotation thereof or a hydraulic damper comprising a hydraulic pump and a variable restriction.

Abstract: A transfer torque control device for a rotational speed responsive type control coupling is provided for providing a desired variation of a transfer torque in response to a variation of a rotational speed differential. The control coupling has orifices for restricting fluid flow therethrough and for thereby producing a transfer torque between first and second axle shafts. The transfer torque control device controls the orifices in such a manner that the openings of the orifices are varied successively in response to variations of the rotational speed differential to obtain the desired torque transfer characteristic.

Abstract: In a rotational speed differential responsive type control coupling, restrictions of a fixed opening are provided for restricting discharge of oil through discharge passages and thereby producing an oil pressure for urging relative rotatable coupling members against each other. By-pass passages are provided for by-passing the restrictions and thereby preventing production of the oil pressure for urge of the coupling members. The by-pass passages are selectively opened and closed by means of a control valve.

Abstract: A device to oppose a difference in relative rotational velocity between two rotatable shafts includes a set of primary braking elements arranged to rotate with one of the shafts and a set of secondary braking elements arranged to rotate with the other shaft, whereby both sets of braking elements are moved into engagement with one another from a free running position in order to oppose the difference in rotational velocity between the two shafts. One of the shafts carries a rotatable unit having a circular surface which is slightly displaced from a 90 degree angle from the drive shafts. This unit is connected for rotation with one set of the braking elements and is movable sideways relative to the other set of braking elements connected to the other shaft.

Abstract: With a differential gearing having a spur gear construction, the compensating gears (31a, 31b) are installed in meshing pairs and are tightly enclosed by a housing (14) so that with meshing spur gears (22, 23) they can act as toothed pumps with pressure zones, with a locking moment being produced between the two driven shafts (2,3). A substantial increase in the locking moment is achieved in that the compensating gears constructed as pinions are disposed in a determined sequence on the circumference of the spur gears and also comprise along their face width partitions (32) which prevent a reduction in pressure along the toothing. As a result with an equal number of pinion pairs there is produced a number of pressure zones which is more than double and consequently there is an increase in the locking moment developed.

Abstract: A method of and system for controlling a torque distribution over four wheels of four-wheel drive vehicle when the vehicle is making a turn. When an outer wheel revolution speed is higher than an inner wheel revolution speed, a differential action limiting force is decreased or weakened and a torque distribution ratio, viz., a ratio of a portion of torque distributed toward the front wheels (secondary driving wheels) to the remaining portion of torque distributed toward the rear wheels (primary driving wheels), is decreased. When the inner wheel revolution speed is higher than the outer wheel revolution speed, the differential acting limiting force is increased or strengthened and the torque distribution ratio is increased.

Abstract: An active torque distribution controller for the wheels of a motor vehicle detects a longitudinal acceleration and a side acceleration to which the vehicle is subject. Based on these longitudinal and side accelerations, a running mode which the vehicle is involved in is detected, and a torque distribution ratio of a portion of torque delivered to the front wheels to the remaining portion to the rear wheels and a differential limiting force are varied in response to a predetermined control schedule for the running mode detected.