Abstract: A power transmission device for four wheel drive vehicle includes a differential motion limiting device, for limiting differential motion of a center differential device, which is made up by a wet-type frictional clutch and a hydraulic actuator. Under running condition, the frictional clutch is engaged by certain engaging force, and considering frictional coefficient of roads, the clutch is engaged with some slips so that torque distribution to front and rear wheels becomes even (50:50), then torque is distributed from the center differential device to front and rear wheels. The line pressure is applied to the hydraulic actuator through a regulator valve. In normal running condition, the regulator valve reduces the line pressure pre certain ratio, the reduced pressure is applied to the hydraulic actuator. In the case the manual valve being shifted to R range or low speed position, the regulator valve is switched to apply the line pressure directly to the hydraulic actuator.

Abstract: A four-wheel drive vehicle has a front wheel side having a front wheel set, a rear wheel side having a rear wheel set, an engine having an output shaft extending in a transverse direction of a vehicular body, a transmission having an input shaft connected to the output shaft of the engine and an output shaft connected through a transmission mechanism to the input shaft such as to extend in a transverse direction of the vehicular body, a rotating member connected to the output shaft of the transmission, a front differential gear, a first output member connected between the rotating member and one of the wheel sets for transmitting power to one of the wheel sets through the front differential gear, a second output member coaxial with the first output member, a rear wheel propeller mechanism between the second output member and the other wheel set, and operative to convert the rotation of the second output member into rotation about an axis perpendicular to the axis of rotation of the second output member for dr

Abstract: Described herein is a hydraulic servo for a friction coupling element of an automatic transmission, which is mounted in association with a one-way clutch and which has reduced dimensions in radial and axial directions. The hydraulic servo essentially comprises: an annular drum splined with a sleeve portion of the inner race of the one-way clutch and arranged to receive the reaction of the one-way clutch by a fixed member in the automatic transmission case; a piston fitted in the annular drum; and a return spring mounted in the drum for returning the piston.

Abstract: A hydraulic control system for an automatic transmission has a shifting shock reducing device capable of regulating the transitional oil pressure applied to the frictionally engaging devices of the automatic transmission, and provided between a shift valve and the frictionally engaging devices. The shifting shock reducing device is controlled on the basis of a signal representative of the torque of the engine, and a signal representative of the transitional shift state to regulate the transitional oil pressure. Thus, the hydraulic control system is highly reliable, is capable of compensating for variations of the functions thereof over time, and is capable of maintaining a high control accuracy.

Abstract: Herein disclosed is an accumulator for suppressing an abrupt rise in and suppressing the pressure of a fluid. In this accumulator, a coil spring for urging a piston fitted in a cylinder in the axial direction thereof is secured on the pistion by securing it on one side of a plate and by securing the plate on the piston. The plate is formed with a cylindrical nub, on which is fitted on turn of the coil spring. This coil spring is secured on the plate by deforming the nub radially outward to trap that one turn of the coil spring. The plate in turn is secured in a bottomed cylindrical hollow portion which is formed in the piston.

Abstract: Herein disclosed is a transaxle casing to be used with a transverse type automatic transmission. An arcuate partition extending from the top to the bottom of a transmission gear case is disposed between the radially outermost rotary member of the transmission gear seat and a cover wall and in front of the transmission gear set with respect to the running direction of a vehicle. An oil sump is disposed below the transmission gear set. Thus, the lubricating oil splashed away the rotary member is guided into an oil return passage extending between the partition and the cover wall and opening into the oil sump so that it may be prevented from being caught again by the transmission gear set and heated to a high temperature.

Abstract: In an accumulator including a piston which slides freely in a cylinder and a spring which presses the piston, a hole of the piston end where, at the bottom, a large diameter section is made, and small diameter section whose diameter is smaller than that of the large diameter section is located at another side of the large diameter section is located at another side of the large diameter section against the bottom of the hole is provided, and the spring assembly having the retaining member and the coil spring whose one end is fixed to the retaining member and another end is free is provided, and the snap ring is provided to hold the retaining member between the bottom of the hole and the snap ring which is installed in the large diameter section with radial expansion force, so that the spring assembly is installed in the hole of the piston.

Abstract: In a hydraulic torque converter having a torus of flatness ratio (L/H) within the range 0.82-0.9, the outer and inner contours of the turbine in a meridional plane through the axis of the turbine each comprises a combination of a plurality of circular arcs, wherein the ratios between the radii of the circular arcs constituting said outer contour is substantially less than 2, and the ratios between the radii of the circular arcs constituting said inner contour is substantially less than 2.As a result, fluid flows through the turbine stably without being biased, increasing the velocity of relative flow along the turbine blade, and raising the normal speed ratio at which the absolute flow is in the direction of no impact, enabling a higher stall torque ratio without reduction in efficiency.

Abstract: Herein disclosed is a fluid pressure control system which is to be used in an automatic transmission for automobiles. If a reverse range is selected by selector means such as a manual valve, a fluid pressure is fed via an accumulator to friction engaging means for setting the reverse range, and a signal pressure is fed to back pressure regulating means which is constructed of a spool valve. This back pressure regulating means responds to the signal pressure to reduce a load against the fluid pressure to be fed to the friction engaging means. Thus, the fluid pressure to be fed to the friction engaging means via the accumulator drops when the signal pressure is fed. In the reverse range, specifically, the fluid pressure to be fed to the friction engaging means transmits at a lower level to elongate the time period for the engagement so that the gear shift shock for the reverse range is accordingly reduced.

Abstract: Described herein is a hydraulic control system for vehicular automatic transmission, including an accumulator back pressure control circuit which is provided between a line pressure conduit and a back pressure supply conduit, and comprises a first accumulator control valve for dropping the line pressure according to the throttle opening, and a second accumulator control valve receiving an input pressure commensurate with the throttle opening and dropping the output pressure of the first accumulator control valve according to the throttle opening to apply to the piston of the accumulator a back pressure varying in corresponding to the engine output shaft torque.

Abstract: An automatic transmission includes a fluid torque converter and a first and second gear transmission mechanisn, each of which has two coaxial drive members--a power input member and a power output member--and is selectable to any one of several speed radios. Rotational power is output from the fluid torque converter to the power input member of the first gear transmission mechanism. The torque converter, and the first gear transmission mechanism including the power input and output members thereof are all coaxial on a first axis.

Abstract: In an automatic transmission control system incorporating the conventional line, throttle, and governor fluid pressure regulation valves, mannual selector valve, and shift valves such as 1/2, 2/3, and 3/4 shift valves, there is further incorporated a modulator fluid pressure control valve which produces a modulator fluid pressure of a predetermined constant level from the line pressure available from a port of the manual selector valve when it is shifted to a lower range, such as, for example, 2 range. The line fluid pressure regulation valve, which is normally boosted by the throttle pressure, is instead boosted by the modulator fluid pressure when the modulator fluid pressure is present while the throttle fluid pressure is very low as at the time when the manual selector valve has been shifted from the D range to the 2 range for effecting rapid deceleration of the vehicle, so as to support the governor pressure, generated from the line pressure, at a high level while the vehicle speed is still high.

Abstract: A vehicle automatic transmission includes a torque converter which has a rotational power output member, and also includes a gear transmission mechanism. This gear transmission mechanism includes; a friction engaging mechanism; first and second rotational power input members; a first clutch which selectively engages the torque converter rotational power output member to the first rotational power input member; and a second clutch which selectively engages the torque converter rotational power output member to the second rotational power input member.

Abstract: A torque converter includes a coaxially mounted pump impeller, turbine, and stator, each of which includes an outer shell, an inner shell, and vanes extending between the outer shell and the inner shell having edges which define an inlet and outlet. The pump impeller outlet is proximate to the turbine inlet, the turbine outlet is proximate to the stator inlet, and the stator outlet is proximate to the pump impeller inlet. The outer and inner shells cooperate to define outer and inner toroidal surfaces, which together define a hollow toroidal hydraulic fluid circulation path. The ratio between the axial extent and the radical extent of a section of the outer toroidal surface is less than approximately 0.9.

Abstract: In a four wheel drive power transmission system for an automotive vehicle, including a planetary gear mechanism wherein the carrier, the ring gear and the sun gear thereof operate as a power input member, a first power output member for driving either of a pair of front wheels or a pair of rear wheels and a second power output member for driving the other of the pair of front wheels and the pair of rear wheels, respectively, the planetary gear mechanism being selectively locked to rotate as a unitary rotational member, a clutch is incorporated in a rotational power transmitting system for rotationally connecting the ring gear with either the pair of front wheels or the pair of rear wheels so as selectively to intercept the rotational power transmitting system between, wherein the first power output member provides hundred percent front or rear wheel drive when operated with the planetary gear mechanism being locked, while the second power output member provides high percentage opposite rear or front wheel dri

Abstract: A rotary power transmission device including a hydraulic torque converter which transmits rotary power between coaxial power input and power output shafts, and a lock up clutch system which also transmits rotary power between the power input and power output shafts, wherein the lock up clutch system includes a rotary shock absorber including a disk shaped plate element and two ring shaped plate elements cooperating with an outer peripheral portion of the disk shaped plate element in an axially superposed manner so as to provide a rotary shock absorber, one of the two ring shaped plate elements being positioned between the other ring shaped plate element and the disk shaped plate element, the assembly of the two ring shaped plate elements and the outer peripheral portion of the disk shaped plate element being positioned in an annular space formed adjacent an outer peripheral portion of the turbine of the hydraulic torque converter, while the radially inner portion of the disk shaped plate element is rotational

Abstract: A four wheel drive power transmission for a vehicle has a center differential device for distributing rotational power supplied from an engine to a front wheel propeller shaft and a rear wheel propeller shaft at a variable torque dividing ratio therebetween, and a mechanism for controlling the center differential device so as to vary the torque dividing ratio according to the magnitude of the torque of the rotational power supplied from the engine so that the torque dividing ratio is varied toward a decreased ratio for one of the front and rear wheel propeller shafts and an increased ratio for the other of the front and rear wheel propeller shafts as the magnitude of torque of the rotational power supplied from the engine increases. The torque loaded on one of the front and rear wheel propeller shafts is maintained not to exceed a determinate value as torque increases.

Abstract: A four-wheel drive vehicle has a front wheel side having a front wheel set, a rear wheel side having a rear wheel set, an engine having an output shaft extending in a transverse direction of a vehicular body, a transmission having an input shaft connected to the output shaft of the engine and an output shaft connected through a transmission mechanism to the input shaft such as to extend in a transverse direction of the vehicular body, a rotating member connected to the output shaft of the transmission, a front differential gear, a first output member connected between the rotating member and one of the wheel sets for transmitting power to one of the wheel sets through the front differential gear, a second output member coaxial with the first output member, a rear wheel propeller mechanism between the second output member and the other wheel set, and operative to convert the rotation of the second output member into rotation about an axis perpendicular to the axis of rotation of the second output member for dr

Abstract: A four-wheel drive vehicle has an engine output shaft; a transmission having an input shaft connected to the output shaft and an output shaft connected through a transmission mechanism to the input shaft; a drive gear meshed with an output gear connected to the output shaft of the transmission; a front wheel side power transmitting mechanism; a rear wheel side power transmitting mechanism; a center differential mechanism coaxial with the drive gear and having an input member connected to the drive gear, a first output member connected to the front wheel side power transmitting mechanism, and a second output member connected to the rear wheel side power transmitting mechanism; a front differential gear coaxial with the center differential mechanism and connected to the first output member of the center differential mechanism; a power converting gear mechanism for converting a rotation about a first axis to a rotation about a second axis being perpendicular to the first axis to transmit power to the rear side p

Abstract: A hydraulic servo for friction coupling devices of automatic transmissions, the hydraulic servo comprising: an annular drum including outer and inner cylinders and a side wall connecting the two cylinders together and mounted fixedly or rotatably within an automatic transmission case; an intermediate cylinder mounted concentrically in a predetermined position between the outer and inner cylinders of the drum; a return biasing means located between the intermediate and inner cylinders; and a connecting member securely connecting the return biasing means to a piston.