Abstract: A planetary differential assembly is disclosed. The planetary differential assembly can spit driving torque generated by an engine of a vehicle (which uses the assembly) into two parts at an appropriate ratio to realize an optimum driving condition of the vehicle in traveling even when one of driving wheels of the vehicle loses traction on a bad-condition road. The above appropriate splitting of the driving torque is accomplished by applying a braking torque to each of component gears of a planetary gear set of the assembly. Such braking torque is produced: by reducing at least one of backlashes between these component gears to a possible minimum amount; and/or by roughing an outer peripheral surface of each of pins on which the components gears are rotatably supported, respectively; and/or by roughing an inner peripheral surface of each of central through-holes of the component gears, through which surface each of the gears is brought into a slidable contact with each of the pins.

Abstract: A hub clutch device for connecting and disconnecting an axle and a wheel in a part time four-wheel drive vehicle is disclosed closed. The hub clutch device is provided with an outer race secured to a vehicle body, an inner race having a flange portion secured to the wheel and a hub portion provided with a gear portion at a peripheral inner portion, defining a fluid passage with the axle, and a roller member positioned between the outer race and the inner race. A movable wall is positioned inside of the hub portion. The movable wall defines a sealed chamber with the hub portion and is movable in an axial direction of the axle. The sealed chamber communicates with the fluid passage. A sliding gear always engages the gear portion of the hub portion and is axially movable according to the motion of the movable wall to engage a gear part of the axle to connect the axle with the wheel in a rotational direction.

Abstract: To simplify propeller shaft supporting structure and to reduce propeller shaft vibration when a viscous coupling and a clutch mechanism are both provided on a propeller shaft of a 4WD vehicle, the power transmission apparatus comprises a housing rotatably supported to receive power; a differential gear disposed on one side of and within the housing; a viscous coupling disposed on the other side of and within the housing; and a clutch for transmitting power from the housing to the differential gear via the viscous coupling when engaged, and transmitting no power from the housing to the differential gear when disengaged.

Abstract: To stably control clutch engagement torque of a multidisk friction plate clutch provided between two rotary members, without being directly subjected to the influence of friction plate wear or of fluctuations in friction coefficient between two clutch plates, the coupling apparatus comprises a pilot clutch, a main clutch and dual cam ring members disposed between the two clutches. When the pilot clutch is engaged by an actuator in a first direction, since a first slidable cam ring rotation is limited by the pilot clutch relative to a second fixed cam ring, the first slidable cam ring is shifted in a second opposite direction by a cam thrust force to engage the main clutch. The coupling apparatus is suitably incorporated in a differential gear assembly mounted on automotive vehicles in order to controllably and stably limit the differential motion between two shafts.

Abstract: A limited slip differential for limiting differential rotation between a differential casing and axles via a frictional connection includes a pinion shaft rotating integrally with the differential casing and a pinion gear attached rotatively to the pinion shaft. A side gear engages with the pinion gear and is mounted loosely with respect to the axles. A first cam portion formed on the side gear engages with a second cam portion formed on a driving member which is spline-engaged with one of the axles, supporting the side gear and supported by and centered on the differential casing. A frictionally connecting clutch is disposed between the driving member and the differential casing.

Abstract: To restrict and further promote differential rotation between first and second output shafts, the power transmission apparatus for differentially transmitting a rotative power supplied to an input shaft to two output shafts comprises a differential gear mechanism coupled between the two output shafts; a multiplying mechanism associated with the differential gear mechanism, for detecting and multiplying a differential rotation; a motor coupled to the multiplying gear mechanism, for restricting or promoting the differential rotation by driving the multiplying gear mechanism in either direction; and a controller for controlling rotative direction and torque of the motor by adjusting supply voltage polarity and motor current magnitude. The multiplying mechanism is a strange gear mechanism or a planetary gear mechanism.

Abstract: To realize three functions of twin viscous coupling in four-wheel drive, free coupling in two-wheel drive, and further direct (lock) coupling in four-wheel drive, the power transmission apparatus for transmitting power from a propeller shaft (9A) to two right and left rear wheel drive shafts (21A, 23A), comprises first and second hubs (4, 5) coupled to the drive shafts; cylindrical inner and outer casings (3a3b) for forming two working chambers (11, 12) in cooperation with the two hubs; first and second resistance plates (8, 9), and a driven member (17) for selectively engaging the inner casing with the outer casing (TWIN VISCO IN 4WD) and disengaging the inner casing from the outer casing (FREE IN 2WD).

Abstract: To obtain a wide transmission torque adjustable range at a short stroke in a viscous coupling clutch including a first rotatable member and a second rotatable member rotatably and slidably disposed relative to the first rotatable member so as to form a working chamber filled with a viscous fluid, without increasing the clutch size and cost, first and second cylinder assemblies of different diameters are coaxially fixed to the first and second rotatable members, respectively in such a way that a radial thickness of each of the resistance cylinder members changes stepwise along the axial direction thereof to stepwise change the overlap and gap (i.e. viscous coupling) conditions between the first and second cylinder assemblies, when the first rotatable member is moved axially relative to the second rotatable member.

Abstract: A fluid composition for use in a viscous coupling is provided, which comprises (A) a base oil made of a polyorganosiloxane fluid having a viscosity of from about 500 to about 500,000 centistokes at 25.degree. C., and (B) at least one component selected from the group consisting of sulfur and sulfur compounds (b) to (g) listed below being added in a minor amount to said base oil;(b) a hydrocarbon sulfide;(c) a sulfurized oil or fat which is the reaction product of an oil or fat and sulfur;(d) a zinc dithiophosphate;(e) a dialkyldithiocarbamic acid metal salt;(f) elemental sulfur; and(g) a cyclic hydrocarbon sulfide.This fluid composition can be stably used in a viscous coupling for an extended period.

Abstract: To incorporate a viscous coupling type power transmission apparatus for a four-wheel driven automotive vehicle with an antiskid braking system, viscous torque transmission from a first rotary transmission shaft (coupled to the front wheel shaft) to a second rotary transmission shaft (coupled to the rear wheel shaft) is intermitted by a clutch mechanism provided for the power transmission apparatus whenever a foot brake is applied. That is, when a foot brake pressure is applied to the brake member of the power transmission apparatus, the clutch mechanism is disengaged via a cam ring to decouple the first rotary transmission shaft from the second rotary transmission shaft.

Abstract: A power transmission apparatus comprises first and second rotary devices rotatable with respect to each other, a resistance device transmitting power between the first and second rotary devices by the viscous resistance of a viscous fluid, and a device for externally emitting heat generated between the resistance device and the viscous fluid through a lubricant flowing through the connecting portion between the first and second rotary devices.

Abstract: A differential apparatus comprises first and second rotary devices rotatable with respect to each other, a viscous clutch having a chamber filled with a viscous fluid and restricting a differential operation generated between the first and second rotary devices by the resistance of the viscous fluid, a friction clutch separated from the viscous clutch and restricting the differential operation, and a device for preventing the seal of the chamber from being reduced by an increase in pressure within the chamber and actuating the friction clutch in accordance with an input torque.

Abstract: A differential gear assembly has a friction clutch for restricting differential action. The clutch is actuated by an actuator which moves in a linear direction. The actuator is driven remotely in one embodiment by means of a rotating element, and in another embodiment by means of a spring biased pivotal element.

Abstract: There is provided a power transmission unit comprising an input member for receiving a torque input from a ring gear connected to a drive pinion which is connected to a propeller shaft, first and second output members supported by the input member in a freely rotatable manner and engaged with right and left rear wheels, and first and second clutches arranged between the input member and the first and second output members respectively to release the connections between the input member and the first and second output members respectively with the help of the actions of cam devices for releasing clutches when the angular speed of the input member becomes smaller than those of the first and second output members.

Abstract: A power transmission apparatus comprises first and second rotary devices rotatable with respect to each other, a sealed chamber hermetically formed between the first and second rotary devices and filled with viscous fluid, first and second resistance devices disposed within the sealed chamber and respectively rotatable together with the first and second rotary devices to transmit torque therebetween by the shearing resistance of the viscous fluid, and a third device for controlling the pressure within the sealed chamber in accordance with the running state of an object provided with the power transmitting apparatus.

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 transfer case for four-wheel-drive vehicles for distribution of the power from an input shaft through a transmission route to the rear propeller shaft and the front propeller shaft is shown. The transfer case is provided with a torque detection unit for detecting the torque on the input shaft side and is equipped also, on the transmission route between the rear propeller shaft side and the front propeller shaft side, a friction clutch whose coupling force is adjusted in accordance with the variations in the values of the torque detected by the torque detection unit.

Abstract: A power transmission apparatus having an input shaft connected, by planetary gearing, to two coaxially arranged output shafts. The planetary gearing permits differential rotation between the output shafts. A limiting device located between the output shafts to limit the differential rotation thereof. The limiting device includes a clutch member mounted on the first output shaft and alternating first and second clutch plates. The first plates are axially movable relative to and rotatably fixed to the clutch member, and the second plates are axially movable relative to and rotatably fixed to the second output shaft. An interengaging cam mechanism is carried on the clutch member and the first output shaft, and arranged such that upon relative angular movement between the clutch member and the first output shaft, the clutch member is moved axially to frictionally engage the first and second clutch plates.

Abstract: A power transmission device is provided. The device comprises a casing for receiving a torque input, output members arranged inside the casing, movable members provided movably around the output members respectively, one side face of each of the movable members forming a cam face, clutches adapted for connecting the casing with the output members, and a cam shaft fixed to the casing and located between the movable members, wherein the torque input of the casing is transmitted to the output members through two routes, i.e., through the cam and the movable members, and through the clutches. The power transmission device is further provided with several improved parts such as improved friction faces, resistant members, cam faces, and pin.

Abstract: A viscous coupling for a drive shaft has an elongated tubular first shaft and an elongated cylindrical second shaft extending into and cooperating with the first shaft to define a cylindrical clearance therebetween. Bearings for accommodating both relative rotation and axial displacement of the first and second shafts are interposed therebetween at opposite ends of the clearance. Seals are associated with the bearings to hermetically seal the ends of the clearance, which is filled with a viscous fluid. The viscous resistance of the fluid to rotation of one shaft relative to the other provides a means of transmitting torque therebetween.