Abstract: A torque transfer mechanism having a multi-plate friction clutch connecting a pair of rotary members and an electrohydraulic clutch actuator for controlling engagement of the friction clutch. The clutch actuator includes a hydraulic pump, a hydraulically-actuated rotary operator, and a ball ramp mechanism. The hydraulic pump draws low pressure fluid from a sump and delivers high pressure fluid to a series of actuation chambers defined between coaxially aligned first and second components of the rotary operator. The magnitude of the fluid pressure delivered to the actuation chamber controls angular movement of the second component relative to the first component for energizing the ball ramp mechanism. The ball ramp mechanism applies a clutch engagement force on the friction clutch assembly, thereby transferring drive torque from the first rotary member to the second rotary member. A hydraulic control system adaptively regulates the fluid pressure delivered to the actuation chamber.

Abstract: An improved inter-axle differential locking clutch is provided that aligns the actuator and the clutch member thereby reducing space and material requirements in the axle assembly housing. The clutch also eliminates the need for a pushrod and shift fork thereby reducing tooling and production costs, as well as eliminating issues associated with misalignment of the piston and pushrod, relative rotation of the shift fork and clutch member, and tipping of the shift fork. The clutch includes one or more pistons disposed within either the axle housing or a carrier supporting the input shaft bearing. Fluid pressure actuates the pistons against a clutch member causing selective engagement between the clutch member and either a side gear driven by the inter-axle differential or a differential case housing the differential gears of the inter-axle differential.

Abstract: An integrated control system for a motor vehicle including at least one drive axle having left and right axle shafts each provided with a wheel mounted thereon. The integrated control system comprises a vehicle torque control system, a vehicle body roll control system, and a common source of a fluid pressure provided to operate both the vehicle body roll control system and the vehicle torque control system. The vehicle torque control system includes at least one fluid actuated clutch provided to regulate a drive torque distribution between the wheels of the motor vehicle in order to improve traction of the motor vehicle on a drive surface. The vehicle body roll control system includes at least one force device provided to tilt a vehicle body relative to a vehicle chassis so as to counteract a rollover-inducing force.

Abstract: An integrated control system for a motor vehicle including at least one drive axle having left and right axle shafts each provided with a wheel mounted thereon. The integrated control system comprises a vehicle torque control system, a vehicle body roll control system, and a common source of a fluid pressure provided to operate both the vehicle body roll control system and the vehicle torque control system. The vehicle torque control system includes at least one fluid actuated clutch provided to regulate a drive torque distribution between the wheels of the motor vehicle in order to improve traction of the motor vehicle on a drive surface. The vehicle body roll control system includes at least one force device provided to tilt a vehicle body relative to a vehicle chassis so as to counteract a rollover-inducing force.

Abstract: A drive axle assembly (10) includes a carrier (24) for supporting a differential case (22) with axle shafts (14, 16) extending therethrough and rotatable with the differential case (22) relative to the carrier (24). A plurality of friction discs (74, 76) are disposed within the differential case (22) and are alternatively connected to the differential case (22) and a drive hub (78), which is connected to one of the axle shafts (14). A sleeve (100) is operably connected to a piston (90) for generating a thrust force and for transmitting the thrust force through the sleeve (100) to move the friction discs (74, 76) closer together. A plurality of levers (104) are operably connected one with the other and disposed between the sleeve (100) and the friction discs (74, 76) to amplify the thrust force of the sleeve (100).

Abstract: A drive axle assembly for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control to a first wheel and an adaptively controlled second hydraulic coupling for providing front-to-rear torque control to a second wheel. The drive axle assembly is contained with a common housing and communicates with a traction control system to actively control actuation of the first and second hydraulic couplings based on the operating characteristics of the vehicle as detected by suitable sensors.

Abstract: A drive axle assembly for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control to a first wheel and an adaptively controlled second hydraulic coupling for providing front-to-rear torque control to a second wheel. The drive axle assembly is contained with a common housing and communicates with a traction control system to actively control actuation of the first and second hydraulic couplings based on the operating characteristics of the vehicle as detected by suitable sensors.

Abstract: An apparatus and method for controlling a limited slip differential uses a solenoid operated valve having an armature attached a differential case of the differential for rotation therewith, and an actuating coil operatively attached to a non-rotating differential housing, for modulating pressure in a hydraulically actuated limited slip device of the limited slip differential. The actuating coil is mounted on a non-rotating plenum, sealed to the differential case with low pressure dynamic seals.

Abstract: A yaw management system for a vehicle with driveline torque control is comprised of sensors to determine the rate of change of yaw in the vehicle, a controller for receiving information from the sensors, and a means for using that information to selectively transfer torque from the inner half shaft axles of the vehicle to the outer half shaft axles of the vehicle for regulating the torque delivered to the drive wheels.

Abstract: A pressure control valve assembly is disposed in the hydraulic flow path of a differential assembly and is connected to a passageway leading to a limited slip device within the differential case to establish fluid communication there between. The valve assembly includes a machined or formed blind hole, a groove which partially intersects the blind hole, a ball member seated in the blind hole, and a spring resiliently acting on the ball to apply a force biasing the ball into the blind hole. At the intersection of the blind hole and groove, an area, which is not sealed by the ball, is formed that provides a controlled leakage path for the hydraulic fluid.

Abstract: A shiftable transmission in which at least two clutches (2, 7) actuated in closing direction by spring force and in opening direction by the exertion of pressure are arranged, wherein output of the transmission is stopped by unpressurized shifting of both actuation devices (9, 13) thereby closing both clutches (2, 7). When pressure is exerted upon the second actuation device (13), the actuation force of the first actuation device (9) is composed of a spring force of the first actuation device (9) and a hydraulic force from the pressurization of the second actuation device (13). The clutch belonging to the first actuation device can thus be impinged upon with different forces depending on whether or not the second actuation device is impinged upon with pressure.

Abstract: A differential assembly for a motor vehicle comprises a differential case rotatably supported in an axle housing, opposite output shafts drivingly connected to the differential case, a friction clutch pack for controlling the differential action, and a hydraulic clutch actuator for selectively fictionally loading the clutch pack. The hydraulic clutch actuator includes a variable pressure relief valve assembly to selectively control the friction clutch pack. The variable pressure relief valve assembly includes a valve closure member, a valve seat complementary to the valve closure member, and an electro-magnetic actuator for engaging the valve closure member and urging thereof against the valve seat with an axial force determined by a magnitude of an electric current supplied to the electro-magnetic actuator so as to selectively vary a release pressure of the pressure relief valve assembly based on the magnitude of the electric current.

Abstract: A drive axle for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control and a passively controlled second hydraulic coupling for providing side-to-side limited slip and torque biasing control. The drive axle is contained with a common housing and communicates with a tractor control system to actively control actuation of the first hydraulic coupling based on the operating characteristics of the vehicle as detected by suitable sensors.

Abstract: A drive axle for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control and a passively controlled second hydraulic coupling for providing side-to-side limited slip and torque biasing control. The drive axle is contained with a common housing and communicates with a tractor control system to actively control actuation of the first hydraulic coupling based on the operating characteristics of the vehicle as detected by suitable sensors.

Abstract: A novel arrangement of a limited slip differential assembly comprising a differential case housing a friction clutch assembly provided within a differential case for selectively restricting differential action and a hydraulic actuator assembly including a piston assembly and a bi-directional gerotor pump. The piston assembly includes a hydraulic piston disposed in a piston housing forming a pressure chamber. The piston housing is provided with a removable bleed plug defining a flow restricting bleed passage. The bleed plug is accessible from the outside of the differential assembly without disassembling thereof through an access hole in the differential case. By appropriately selecting a flow area of the bleed passage, the limited slip differential assembly may be tuned to define application rate of torque transfer of the friction clutch assembly.

Abstract: A differential drive for use on a vehicle to control the transfer of torque between the front and rear axles of a vehicle. The differential drive includes a rotatably driven differential housing supported in a housing. The differential drive also includes a differential gear set arranged and supporting in the differential housing. The differential gear set has at least two side shafts gears and at least two differential gears. The differential drive also includes a torque distribution device having a viscous transmission. The viscous transmission has an inner hub and an outer casing. The inner hub is connected to a first side shaft. The outer casing is connected to one of the side gears. The viscous transmission also connects the output of the first side shaft to one of the side shaft gears.

Abstract: A compressed-air-operated differential lock of a motor vehicle, which is arranged within a metallic rear-axle transmission housing part having a recess. A piston is arranged displaceably in the recess in relation to its longitudinal axis and so as to be capable of being supported on a first claw clutch half which is arranged fixedly in terms of rotation in relation to a shaft and so as to be capable of being coupled to a corresponding second clutch half. In order to provide a cost-effective differential lock, a plastic liner is inserted into the recess and receives the piston so as to guide the latter along said longitudinal axis and in which an elastomeric sealing ring is snapped in a way beneficial in mounting terms and seals off relative to the compressed-air interior.

Abstract: A drive axle for an all-wheel drive vehicle includes an adaptively controlled first hydraulic coupling for providing front-to-rear torque transfer control and a passively controlled second hydraulic coupling for providing side-to-side limited slip and torque biasing control. The drive axle is contained with a common housing and communicates with a tractor control system to actively control actuation of the first hydraulic coupling based on the operating characteristics of the vehicle as detected by suitable sensors.

Abstract: A power transmission apparatus comprises a device for transmitting power by frictional force between first and second rotary members rotated relative to each other; a device for pressing the power transmitting device in a direction of increasing frictional force; and a hydraulic fluid delivery system for driving the pressing device in the direction of increasing frictional force, whereby the fluid delivery system is driven by a drive pinion gear stem. In accordance with this invention, the need for a separate hydraulic motor and pump or drive belts is eliminated thereby reducing the complexity and size of the apparatus while providing increases reliability as compared to alternative designs. The present invention also provides a unique advantage of utilizing the axle's own lubricant, thus avoiding potential cross-contamination between a specialized hydraulic fluid and the axle lubricant.

Abstract: A wheel differential having an improved differential lock assembly is provided. The differential includes a differential housing and a differential cage rotatably supported on the differential housing by a set of bearings. The differential also includes a clutch assembly having a first member fixed to the differential cage and a second member configured to receive an axle half shaft extending from the differential cage for rotation with the axle half shaft. Finally, the differential includes an improved differential lock assembly that selectively shifts the first and second clutch members into engagement to prevent relative rotation between the differential cage and axle half shaft. The lock assembly includes a shift chamber that is supported on an outer race member of the set of bearings. The shift chamber may be formed within a bearing cap that is coupled to the differential housing and disposed about at least a portion of the bearing set.

Abstract: An inter-axle differential capable of preventing a skid to achieve stable travel is provided. For this purpose, the inter-axle differential apparatus includes an inter-axle differential (13), an inter-axle differential lock (21), at least one rotation detector of a first rotation detector (27) for detecting rotational frequency of a transmission output shaft (24), a second rotation detector (28) for detecting rotational frequency of a front output shaft (25) of the inter-axle differential, and a third rotation detector (29) for detecting rotational frequency of a rear output shaft (26) of the inter-axle differential, and a controller (20) for detecting a sign of a skid occurring to driving wheels (2, 4) based on at least any one of the rotational frequency detected by the rotational detector and a rate of change with time of the detected rotational frequency and for outputting a differential lock signal to the inter-axle differential lock.

Abstract: A vehicle drive axle includes a differential where high pressure is delivered from a stationary source to a rotating source to actuate a differential clutch. The drive axle includes an axle housing, a first rotatable axle shaft for driving a first wheel, and a second rotatable axle shaft for driving a second wheel. The differential controls rotational speed and torque supplied to the first and second axle shafts. The differential clutch is used to selectively lock the axle shafts together when the vehicle experiences unfavorable road conditions. An actuating mechanism is used to control the differential clutch. The actuating mechanism includes a stationary piston actuated by a fluid force and a rotating piston actuated by the stationary piston. This stationary piston moves the rotating piston causing the rotating member to displace a volume of fluid to actuate the differential clutch.

Abstract: A compact braking assembly in an axle for an industrial vehicle comprising, within an internal body (10) which extends in an arm (18), supported in a rotatable manner (in 16, 17) a casing (14) of a differential (15) provided with a first set of disks (20, 21), with a second set of disks (46, 47) also positioned between the casing (14) and said arm (18) of the axle, with a piston (41) acting on the first set of disks (20, 21), operated by a fluid fed from a respective duct (43), which axially moves a ring (44), distributor of an operating force of the piston (41), in which the piston (41) successively positions the first set of disks (20, 21) in a pack acting as a differential lock, subsequently positioning the second set of disks (46, 47) in a pack acting as a service brake thanks to the presence of a pre-established preloaded elastic element (24).

Abstract: An enclosed axle differential lock is provided which includes an axle carrier assembly within which is a bearing having a bearing cap. A differential housing rotates, supported by the bearing, with a pinion gear and a side gear each rotating in the differential housing and meshing together. An axle is driven by the side gear. A clutch may be used to lock the differential housing and the axle together. The clutch includes a first clutch element fixed to the differential housing and a second clutch element splined on the axle and axially movable thereon, the second clutch element having a first disengaged position in which the first clutch element and the second clutch element are substantially disconnected, and a second engaged position in which the first clutch element and the second clutch element are substantially drivingly connected. An actuator is integrally disposed in the bearing cap which urges the second clutch element from the first disengaged position to the second engaged position.

Abstract: An electronically controlled axle assembly having an electronically controllable valve secured to the differential case to control pressure within a hydraulically actuated clutch pack there within. The clutch pack operates to selectively couple a pair of shafts.

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 differential gear assembly has a friction clutch for variably restricting differential action. A simple hydraulic piston mechanism is used to amplify the axial force generated by the electric coil and mechanical ball ramp mechanism. The hydraulic system consists of an annular primary piston in contact with the clutch pack, and a multiple set of secondary pistons are attached to the unrestrained ball ramp race. Hydraulic fluid fills the cavity between the primary and secondary pistons. This system provides force multiplication proportional to the surface areas of the respective piston faces.

Abstract: A method is provided for determining an acceptable torque level to be applied to at least one clutch pack (of an automobile) which includes the requirement of internal slip to transmit torque. The automobile includes a plurality of wheels. A velocity is sensed at each of the plurality of wheels of the automobile. A speed information value is calculated. The speed information value is a function of the sensed velocities at each of the plurality of wheels. The speed information value is then compared with a calibration table. Finally, the acceptable torque level is determined primarily from the calibration table based on the speed information value.

Abstract: A vehicle drive axle includes a differential where high pressure is delivered from a stationary source to a rotating source to actuate a differential clutch. The drive axle includes an axle housing, a first rotatable axle shaft for driving a first wheel, and a second rotatable axle shaft for driving a second wheel. The differential controls rotational speed and torque supplied to the first and second axle shafts. The differential clutch is used to selectively lock the axle shafts together when the vehicle experiences unfavorable road conditions. An actuating mechanism is used to control the differential clutch. The actuating mechanism includes a stationary piston actuated by a fluid force and a rotating piston actuated by the stationary piston. This stationary piston moves the rotating piston causing the rotating member to displace a volume of fluid to actuate the differential clutch.

Abstract: An inter-axle differential capable of preventing a skid to achieve stable travel is provided. For this purpose, the inter-axle differential apparatus includes an inter-axle differential (13), an inter-axle differential lock (21), at least one rotation detector of a first rotation detector (27) for detecting rotational frequency of a transmission output shaft (24), a second rotation detector (28) for detecting rotational frequency of a front output shaft (25) of the inter-axle differential, and a third rotation detector (29) for detecting rotational frequency of a rear output shaft (26) of the inter-axle differential, and a controller (20) for detecting a sign of a skid occurring to driving wheels (2, 4) based on at least any one of the rotational frequency detected by the rotational detector and a rate of change with time of the detected rotational frequency and for outputting a differential lock signal to the inter-axle differential lock.

Abstract: A vehicle drive axle includes a differential where high pressure is delivered from a stationary source to a rotating source to actuate a differential clutch. The drive axle includes an axle housing, a first rotatable axle shaft for driving a first wheel, and a second rotatable axle shaft for driving a second wheel. The differential controls rotational speed and torque supplied to the first and second axle shafts. The differential clutch is used to selectively lock the axle shafts together when the vehicle experiences unfavorable road conditions. An actuating mechanism is used to control the differential clutch. The actuating mechanism includes a stationary piston actuated by a fluid force and a rotating piston actuated by the stationary piston. This stationary piston moves the rotating piston causing the rotating member to displace a volume of fluid to actuate the differential clutch.

Abstract: A vehicle differential includes a case which is rotatably supported within an axle housing. The case is formed having a center wall which divides the interior of thereof into first and second fluid chambers. The ends of a pair of axle shafts extend into the case and respectively within the fluid chambers. Each of the fluid chambers is filled with a rheological fluid. Respective electromagnetic coils are disposed within or adjacent to each of the fluid chambers. An electronic controller is provided for supplying electrical current to each of the electromagnetic coils in response to sensed operating conditions of the vehicle, such as rotational speed and torque of the axle shafts. By varying the magnitude of the electrical current supplied to the electromagnetic coils, the strength of the magnetic field applied to the rheological fluid contained in each of fluid chambers can be varied.

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: 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 driving force distributing device is provided for distributing a driving force of an engine to the left and right wheels of a vehicle by bringing a pair of hydraulic clutches into and out of their engaged states. The distributing device includes a hydraulic pump mounted within a casing thereof and driven through gears by a half shaft connected to one of the wheels. An oil passage interconnects the hydraulic pump and the hydraulic clutches, the oil passage being defined in a casing. A valve block is coupled to an upper surface of the casing. Thus, the oil passages interconnecting the hydraulic pump and the hydraulic clutches of the driving force distributing device can be compactly formed.

Abstract: A locking differential has a fixed drive dog and a movable drive dog. A locking actuator has a plunger drivingly connected to the movable drive dog. The plunger is movable in a first direction to a lock position in which the drive dogs are engaged and in a second, opposite direction to an unlock position in which the drive dogs are disengaged. A piston is connected to the plunger and disposed in a cavity in a housing. Movement of the piston in the second direction is imparted to the plunger when the plunger is in the lock position but the piston is movable independently relative to the plunger in the first direction when the plunger is in the unlock position. A pressurized fluid causes the piston, and thereby the plunger, to move in the second direction. A piston bias member biases the piston in the first direction, and a plunger bias member biases the plunger in the first direction. A related method of locking the differential is also disclosed.

Abstract: A hydraulically-operable locking differential includes a retainer ring that is threadably connected with the axle housing for adjustably supporting the bearings at one end of a differential casing, which retainer ring contains ducting for supplying pressure fluid to a hydraulic actuator contained within the casing, thereby to activate a friction pack assembly to lock a side gear of the differential to the differential casing. The ducting for the hydraulic fluid includes a first passage contained in the retainer ring, a second passage contained in and extending longitudinally of a tubular end portion of the casing, and a third passage which affords continuous communication between the first and second passages during rotation of the casing relative to the axle housing.

Abstract: A system for controlling a four-wheel drive for a motor vehicle comprises a drive mode switch for detecting a drive mode of the motor vehicle selectable between a two-wheel drive mode and a four-wheel drive mode. The four-wheel drive mode is selectable between a direct-coupled four-wheel drive mode. A an auto four-wheel drive mode, a controller controls the distribution of traction between main and secondary driving wheels. A traction transmission train distributes traction between the main and secondary driving wheels. The traction transmission train has an oil pressure supply system having a friction clutch and a solenoid.

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: A power transfer system is disclosed for a four-wheel drive vehicle operable for permitting a vehicle operator to select between various full-time and part-time four-wheel drive modes. The power transfer system includes a dual-planetary gear reduction unit that is operable for establishing high-range and low-range speed ratios, and a synchronized range shift mechanism that is adapted to permit the vehicle operator to shift on-the-fly for establishing full-time and part-time high-range and low-range four-wheel drive modes. The power transfer system includes an slip limiting/torque-biasing arrangement including an interaxle differential and a transfer clutch operable for controlling the magnitude of speed differentiation and torque biasing across the interaxle differential.

Abstract: A multi-plate type frictional clutch for a four-wheel drive vehicle is provided in a transfer unit for effecting variable driving force distribution in a 4WD vehicle. An inner wall of a transfer casing includes rotation restriction members so as to restrict rotational movement according to axial movement of a clutch piston disposed within the transfer casing. A cylinder chamber is defined between the rotation restriction members and the clutch piston. Also, the clutch piston is engageable with a rotational portion of a multi-plate type friction clutch via a thrust shaft receiving member disposed between the piston and the rotational portion of the multi-plate clutch. Further, the rotation restriction arrangement includes a casing boss and a piston boss engageable with an input shaft of the transfer unit according to rotational movement thereof. The engagement strength of the casing boss and the piston boss are set to be substantially low.

Abstract: The present invention teaches an activation apparatus for a differential pawl. Such activation apparatus is designed to prevent damage to components of the differential pawl and/or of the drive train resulting from operator error. When a drive wheel slips, a monitoring means acquires a slip signal; and when a wheel slip signal is present, an interrupt means, which can be provided as a switching apparatus, prevents the preassurization of a pressure-medium-operated actuator of the activation mechanism.

Abstract: An improved locking differential for driving a pair of vehicle axles. The differential includes a rotatable case. A differential pinion is supported by the case and meshes with side gears to drive the axles. A clutch assembly is carried by the case and connects the side gear with the case upon actuation. Fluid power actuates the clutch assembly to connect the case and side gear. The improvement comprises the fluid power means having a seal retainer which encircles a portion of the case. The seal retainer has a system for evenly distributes forces applied to the axially extending portion of the case during delivery of pressurized fluid to the clutch assembly to minimize relative movement between the seal retainer and the case. The system comprises oppositely facing surfaces formed in the seal retainer being substantially equal in area to offset oppositely directed forces acting within the seal retainer when pressurized fluid is communicated to the clutch assembly.

Abstract: Between an input shaft and each of left-wheel and right-wheel axles, a speed change mechanism and a multi-plate clutch mechanism are interposed so that a rotational speed of the axle is changed (for example, increased) by a speed change mechanism and is transmitted to a hollow axle. The multi-plate clutch mechanism is interposed between the hollow axle and a differential case. By coupling the multi-plate clutch mechanism, drive torque is fed from one of the differential case and the hollow axle, said one member rotating at a higher speed, to the other member rotating at a lower speed. When the ratio .alpha. of a rotational speed of the left wheel to that of the right wheel becomes greater than the predetermined value .alpha..sub.0 and transfer of torque in a desired direction is no longer feasible. The multi-plate clutch mechanisms are hence made free. The multi-plate clutch mechanisms are controlled by a control unit.

Abstract: Described is a hydraulic circuit construction of a vehicular left/right drive force adjusting apparatus suitable for use in adjusting drive force to left and right wheels in an automotive vehicle or the like. The vehicular left/right drive force adjusting apparatus is provided with a drive force transmission control mechanism which performs adjustment of drive force. The drive force transmitting apparatus is equipped with a left-wheel-controlling, hydraulically-driven clutch mechanism for transferring drive force to a left-wheel axle or from the left-wheel axle, a right-wheel-controlling, hydraulically-driven clutch mechanism for transferring drive force to a right-wheel axle or from the right-wheel axle, and a hydraulic circuit for driving these clutch mechanisms.

Abstract: A speed increasing/decreasing mechanism is interposed between a left-wheel axle and a right-wheel axle. The mechanism is constructed integrally of a speed increasing mechanism and a speed decreasing mechanism. The speed increasing mechanism is adapted to increase a rotational speed of the left-wheel axle and then to output the thus-increased rotational speed to a first intermediate axle. The speed decreasing mechanism, on the other hand, is adapted to decrease a rotational speed of the left-wheel axle and then to output the thus-decreased rotational speed to a second intermediate axle. A first coupling of the variable transmitted torque capacity type is interposed between the first intermediate axle and the right-wheel axle to transmit drive torque therebetween. A second coupling of the variable transmitted torque capacity type is interposed between the second intermediate axle and the right-wheel axle to transmit drive torque therebetween.

Abstract: A part time four wheel drive vehicle has an axle disconnect in its auxiliary drive axle. The axle disconnect has a clutch sleeve non-rotatably and translatably mounted on an inner axle shaft so that the clutch sleeve translates between a first position where clutch teeth of the clutch sleeve engage clutch teeth of an outer axle shaft and a second position where the clutch teeth disengage. The clutch sleeve includes an integral annular piston that is part of a coaxial motor that shifts the clutch sleeve from one position to the other in conjunction with a return spring. The vacuum motor communicates with an external vacuum source and the axle disconnect includes a float valve for sealing a vacuum port of the vacuum motor to protect the external vacuum source against contamination if the vacuum motor is filled with lubricant in the axle housing leaking into the vacuum motor housing.

Abstract: A power steering and limited slip differential system is provided with a main booster generating a steering effort for front wheels, a directional control valve having a pair of reaction chambers and a friction clutch disposed between a differential gear mechanism and a driving wheel axle for rear wheels and is further added with an auxiliary booster generating a compensation steering effort for the front wheels and a clutch control air cylinder for coupling and decoupling the friction clutch.