Abstract: Pressure regulating system for use in an automatic transmission including a fluid coupling, a belt drive continuously-variable speed transmission mechanism having an input pulley and an output pulley which are rotatably interlocked with a V-belt and a reduction ratio control system for controlling the reduction ratio of the belt drive continuously-variable speed transmission mechanism. The pressure regulating system includes a regulator valve capable of regulating the discharge pressure of an oil pump to provide a line pressure, a reduction ratio detecting valve and a throttle pressure valve. The reduction ratio detecting valve receives the line pressure and provides a pressure which is proportional to the displacement of the movable flange of the output pulley with respect to the corresponding fixed flange.

Abstract: An automatic transmission comprising a fluid torque converter; a transmission gear comprising a first gear unit having three forward-speed gears and one reverse gear and a second gear unit having a high-speed gear and a low-speed gear; and a hydraulic control system comprising first and second shift valves for controlling the shifting between the speed gears of the first gear unit, a third shift valve for controlling the shifting between the high-speed gear and the low-speed gear of the second gear unit, a manual selector valve having five shift positions, i.e. D, I. L, R and P-position, and first, second and third solenoid valves related with the first, second and third shift valves respectively.

Abstract: An optical rotary encoder is provided with a pair of corrective light-emitting and light-receiving elements in addition to a pair of light-emitting and light-receiving elements that are for producing an output in dependence upon the relative rotation of two slitted disks. A corrective reference voltage is produced from the output of the corrective light-emitting and light-receiving elements and an output conforming to the relative rotation is produced with the reference voltage serving as a threshold. If the amount of light produced by the light-emitting element decreases or if the amount of light reaching the light-receiving element is reduced due to a decrease in light transmission through the medium in which the encoder is used, the corrective reference voltage changes accordingly so that accurate output pulses conforming to the relative rotation are obtained at all times.

Abstract: Disclosed is a control apparatus for a four-wheel drive vehicle having a center differential mechanism which allows a difference in rotating speed between front and rear wheels so as to absorb a difference in turning radius developed between the front and rear wheels when the vehicle is cornering, and a center differential clutch for limiting differential action of the center differential mechanism. The control apparatus has front-wheel torque sensor provided on a front-wheel drive shaft. When a negative torque is sensed on the front-wheel side while the vehicle is traveling with a restraint placed upon the differential action of the center differential mechanism, the restraint is reduced or removed automatically. This prevents occurrence of a tight corner braking phenomenon and permits the function of the center differential mechanism to fully manifest itself. The vehicle is kept in a stable and safe traveling condition in which driving force is fully utilized.

Abstract: A hydraulic control system for a belt drive continuously-variable speed transmission comprising a continuously-variable speed transmission means including a primary variable-pitch pulley having a fixed pulley flange fixed to an input shaft and a movable pulley flange adapted to be axially slidable on said input shaft, a secondary variable-pitch pulley having a fixed pulley flange fixed to an output shaft and a movable pulley flange adapted to be axially slidable on said output shaft, and an endless belt interconnecting said primary and said secondary variable-pitch pulleys; and a hydraulic control circuit including hydraulic servomechanisms hydraulically interconnected with the respective movable pulley flanges of said primary and said secondary variable-pitch pulleys for pressing the corresponding movable pulley flanges toward the corresponding fixed pulley flanges, a regulator valve for supplying the pressurized working fluid of a controlled pressure to said hydraulic servomechanisms, and a control valve ca

Abstract: A center differential gear adapted for use in a power transmission device for full-time type four-wheel drive vehicles includes a diff-carrier coupled with a power transmitting front casing covering the front diff-carrier of a front-wheel differential gear and arranged coaxially with the diff-carrier, a side gear coupled to the front wheels, and another side gear coupled to a gear mount casing which transmits power to the rear wheels. The diff-carrier of the center differential gear is supported between the side gear on the side driving the front-wheel differential gear and the gear mount casing in cantilever fasion. The other side gear is spline-coupled directly to the gear mount casing without passing through the diff-carrier.

Abstract: Pulleys are provided with load cam mechanisms which exert axial forces corresponding to transmitted torque, and actuator means such as ball screw mechanisms which shift the movable sheaves of both pulleys in axial direction, wherein the axial forces occuring at the pulleys are carried by their shafts and do not act on the housing. A counter shaft is located between the primary and secondary shafts, the countershaft being rotated to drive the actuator means through gearing such as gearwheels, to alter the drive ratio. During power transmission, the axial forces acting on the movable sheaves of primary and secondary pulleys are converted into torque by the actuator means, where the torques are transmitted to the counter shaft in the form of counteracting torques, so that alteration of drive ratio can be made with slight effort on the counter shaft, equivalent ot the difference between the counteracting torques.

Abstract: An end of a shaft member which is displaced and actuated in conjunction with a shift lever of a transmission presses and displaces a latch which is arranged in such a way as to be able to be displaced in an opposing direction against a cam surface of a cam which is formed on a fixed member to function like a wedge which wedges itself between said cam surface and latch, thereby making the latch engage teeth which are drivingly coupled to an output shaft of the transmission in a parking mechanism of a transmission. A cylindrical support portion is continuously extended from the cam surface so as to guide the end of the shaft member at the time when the end of the shaft member is disengaged from the area between the cam surface and latch.

Abstract: A hydraulic circuit for controlling an automatic transmission. The hydraulic circuit has a control valve connected between a shift valve and a hydraulic servomotor for actuating a frictional engagement element such as a brake in a main transmission unit. The control valve is controlled by a signal from a control means in such a manner that, when the hydraulic servomotor is drained by the operation of the shift valve to disengage the brake, the engagement of a frictional engaging element in another transmission unit is synchronized therewith.

Abstract: A rotational speed detecting device for detecting the rotational speed of a predetermined element of a shifting unit is provided for at least one of a main shifting unit and a sub-shifting unit. A control is provided for controlling a predetermined friction engaging element of at least one of the shifting units according to signals from the rotational speed detecting device, so that shifting operations of both the shifting units will be synchronized when both the units are shifted. Therefore, the output of speed of the transmission is not temporarily increased or decreased and thus, smooth shifting is obtained.

Abstract: A cut-back pressure control device for a multi-speed automatic transmission includes a cut-back valve that has a spool which is controlled by both hydraulic pressure which changes in response to shifting of a sub-transmission unit between high-speed and low-speed modes and a hydraulic pressure which is established by the operation of the main transmission unit at 2nd or higher speeds. The spool is moved to a position where it interrupts the cut-back pressure when the main transmission unit selects the 1st speed while the sub-transmission unit is in the low-speed mode, whereas, when the sub-transmission unit is in the high-speed mode or when the main transmission unit selects the 2nd or a higher speed, the spool is held at a position at which it permits the supply of the cut-back pressure.

Abstract: A transmission control device for controlling a transmission having main and sub transmissions in accordance with the state of running of a vehicle.The transmission control device having this constitution can control the main transmission on the basis of and in accordance with the transmission ratio of the sub transmission so as to optimize power efficiency, performance and fuel consumption in relation to the given ratio.

Abstract: An accumulator control device for controlling the back pressure of an accumulator includes an accumulating control valve having a first port communicating with a control oil source and a second port communicating with an accumulator back pressure chamber. The accumulator control valve is controlled by a oil pressure from a shift control. According to the control position of the shift control, the accumulator control valve controls the communicating state of the first and second ports to increase or decrease the back pressure of the accumulator.

Abstract: A plurality of clutches are disposed at one place in the automatic transmission of the present invention to form a clutch portion, the clutch portion is disposed at a front end portion of the automatic transmission mechanism portion, an annexed transmission part is disposed at a position adjacent to the automatic transmission mechanism portion, and the annexed transmission part is provided with a counter gear which is actuated by an output member of the automatic transmission mechanism portion and is detachably attached with a sub-transmission unit. When the transmission is assembled, a multitransmission stage can be obtained by modifying the clutch portion, and attaching/detaching the sub-transmission unit.

Abstract: A transmission control device for controlling the operation of a transmission system which has an automatic main transmission and a manually operable sub transmission. The shifting characteristics of the sub transmission are controlled in accordance with the level of the torque inputted to the sub transmission, so that the transmission as a whole exhibits a superior speed changing performance.

Abstract: An oil pass for communicating a hydraulic servo a change-over valve is provided with an orifice and a by-pass disposed parallel to one another. The by-pass is provided with a sequence valve. When the hydraulic servo is subjected to less than a predetermined pressure, the sequence valve communicates to the change-over valve and the hydraulic servo through the by-pass, and when the hydraulic servo is subjected to a pressure that is higher than the predetermined pressure, the sequence valve is cut off.

Abstract: A transmission control device for controlling the operation of a transmission system including a main transmission and a sub transmission comprises a control circuit adapted for effecting a change-over of the main transmission between different speed gears in accordance with the level of the torque output from an engine when speed modes of the sub transmission are changed over. It is therefore possible to allow the main transmission to select a gear conformable to the gear ratio set in the sub transmission in accordance with the engine output torque, whereby it is possible to obtain optimum shifting characteristics. In addition, it is possible to widen the shiftable region for the sub transmission.

Abstract: A stepless belt transmission includes a working fluid control unit having a supply port for supplying working fluid to a hydraulic actuator, a discharge port for discharging the working fluid from the hydraulic actuator, a lead mechanism for changing the working fluid pressure internally of the hydraulic actuator by varying the opening degree of the supply port or discharge port in dependence upon vehicle running conditions, and a follow-up mechanism operatively associated with a movable flange displaced by the changed working fluid pressure to restore the port opening degree varied by the lead mechanism. It is possible to achieve highly sophisticated control of transmission ratio in dependence upon vehicle running conditions through a comparatively simple construction and on the basis of a simple control method in which the stroke of the lead mechanism is suitably regulated.

Abstract: An automatic transmission, wherein a first shaft is rotatably supported by the transmission case, and an input shaft is coupled with an engine output shaft. Additionally, a second shaft, comprising a long shaft and a short shaft rotatably mounted thereupon, wherein the short shaft has a helical input gear connected to an output gear of the first shaft by meshing engagement, a differential gear with a large helical drive gear connects to an output gear of the second shaft, and a speed-changing planetary gear connects to the short shaft.

Abstract: Sun gears of a single planetary gear unit and a dual planetary gear unit are connected with respect to each other, carriers of the respective gear units in the connected state are connected to an output member, an input member is connected to a ring gear of the single planetary gear unit through a first clutch and also to a sun gear through a second clutch, and the sun gear and a ring gear of the dual planetary gear unit are stoppable by retaining means. When travelling forward, the ring gear of the single planetary gear unit is inputted with torque from the input member based on the state of connection of the first clutch.