Abstract: A drive system for an automotive vehicle of the front-and-rear wheel drive type, comprising a primary drive mechanism for drive of a set of front road wheels and an ancillary drive mechanism for drive of a set of rear roar wheels, wherein the front road wheels are driven by operation of the primary drive mechanism at a two-wheel drive mode and wherein the front and rear road wheels are driven by operation of both the primary and ancillary drive mechanisms at a four-wheel drive mode. In the drive system, a drive power applied to the primary road wheels is restricted to a predetermined value when the vehicle is driven by the primary and ancillary drive mechanisms at the front-and-rear wheel drive mode.

Abstract: A drive system for an automotive vehicle of the front-and-rear wheel drive type, comprising a primary drive mechanism for drive of a set of front road wheels and an ancillary drive mechanism for drive of a set of rear roar wheels, wherein the front road wheels are driven by operation of the primary drive mechanism at a two-wheel drive mode and wherein the front and rear road wheels are driven by operation of both the primary and ancillary drive mechanisms at a four-wheel drive mode. In the drive system, a drive power applied to the primary road wheels is restricted to a predetermined value when the vehicle is driven by the primary and ancillary drive mechanisms at the front-and-rear wheel drive mode.

Abstract: A hybrid vehicle drive system including an electric motor operated by electric energy, an engine operated by the combustion of a fuel, a transmission, and a synthesizer mechanism. The synthesizer includes a hydraulically operated clutch system and mechanically synthesizes the output of the engine and the output of the electric motor for transmitting a resultant of these outputs to the transmission. The synthesizer mechanism and the transmission are disposed adjacent to each other, to simplify piping arrangements for supplying the clutch system with a working fluid and lubricating the synthesizer mechanism and transmission.

Abstract: A hybrid drive system for outputting the power of an internal combustion engine and the power of a motor generator through a transmission. The transmission includes an input shaft and an output shaft. The motor generator is arranged to have an input/output motor shaft in parallel with the input shaft and the output shaft. The internal combustion engine is arranged to have its output crankshaft on the same axis as that of the input shaft.

Abstract: A hybrid drive system for a motor vehicle, having an engine operated by combustion of a fuel, an electric energy storage device for storing an electric energy, a motor/generator connected to the electric energy storage device, and a synthesizing/distributing mechanism which includes a first rotary element, a second rotary element connected to the motor/generator, and a third rotary element, and an output member connected to the third rotary element, wherein a first clutch is provided for connecting the first rotary element and the engine, and a second clutch is provided for connecting two elements of the first, second and third rotary elements of the synthesizing/distributing mechanism, for rotation of the two elements as a unit.

Abstract: A drive control apparatus for an automotive vehicle having an electric motor and an engine operated by combustion of a fuel, the drive control apparatus including a drive source selecting device for selecting an engine drive mode or a motor drive mode on the basis of a first value in the engine drive mode of a physical quantity relating to a condition of the engine and a second value of the same physical quantity reflecting energy conversion efficiencies of the electric motor, an electric generator and an electric energy storage device during an electricity generating mode. The physical quantity is preferably a fuel consumption amount by the engine. The drive control apparatus may also include an engine output determining device that optimizes the efficiency of the system by determining the output of the engine so as to power the vehicle and also provide surplus power to operate the electric generator and charge the electric energy storage device.

Abstract: An automatic transmission having a construction in which a third planetary gear mechanism is arranged in parallel with CR--CR coupled first and second planetary gear mechanisms so that the drive force is transmitted from the carrier of the first planetary gear mechanism to the ring gear of the third planetary gear mechanism. The input is transmitted to a first sun gear through a first clutch and to a second sun gear through a second clutch. The construction further includes a one-way clutch for fixing the sun gear of the third planetary gear mechanism.

Abstract: A hybrid vehicle having a function for reducing the pumping loss. When the shift is in the reverse position, when an appliance is to be driven while the vehicle is in its stopped state and when the electric motor alone is able to drive the vehicle, the fuel supply to the internal combustion engine is cut off and one of the following is performed: the engine's throttle is widely opened; the engine is decompressing by opening the intake and exhaust valves; or the engine is decompressed by closing the intake valve while opening the exhaust valve. In such a manner, the pumping loss in the internal combustion engine can be reduced. Thus, the drag on the electric motor which would ordinarily be caused by stopping the internal combustion engine can be prevented without the provision of a one-way clutch or other equipment between the internal combustion engine and the electric motor.

Abstract: A drive control apparatus for an automotive vehicle having an electric motor operated by an electric energy generated by an electric generator and stored in an energy storage device, and an engine operated by combustion of a fuel, the apparatus having an electricity generating drive mode in which the vehicle is driven by the engine while the electric generator is operated by the engine to charge the electric energy storage device, wherein a changing control device is operable in the electricity generating drive mode, for controlling the engine to operate in a substantially steady state so as to provide a steady state output, and controlling electric power to be generated by the electric generator such that the electric power corresponds to surplus power of the engine which is equal to a difference between the steady state output of the engine and required vehicle drive power which is currently required to drive the vehicle and which is smaller than the steady state output.

Abstract: A control system is provided for servo hydraulic pressure in an automatic transmission. Upon downshifting, one of first and second frictional engagement devices is released while the other is engaged. A directional control valve is provided to feed or drain servo hydraulic pressure to selectively engage or release the first and second devices. The hydraulic pressure is regulated by a pressure regulator under the control of an electronic control unit. Detectors are also provided to determine input rotation and torque, respectively. The regulator is interposed between the directional control valve and the engaged device. The regulator is controlled to maintain the servo hydraulic pressure at a predetermined value under the control of the electronic control unit until predetermined input rotation is detected and then to gradually raise the servo hydraulic pressure under the control of the electronic control on the basis of the value of input torque.

Abstract: A method is provided for the control of servo hydraulic pressure in an automatic transmission. Servo hydraulic pressure is adapted to engage or release first and second frictional engagement elements arranged in such a relationship that, upon shifting from one particular speed stage to another, one of the first and second frictional engagement elements is released while the other is engaged. The servo hydraulic pressure, engaging one frictional engagement element, is linearly lowered in a torque phase during a shift so it releases the one frictional engagement element, responsive to a rise in the servo hydraulic pressure to the frictional engagement element to be engaged, to maintain an inversely proportional relationship between the servo hydraulic pressure being raised and that being released.

Abstract: A control system is provided for servo hydraulic pressure in a vehicular automatic transmission having planetary gear mechanisms. Shifting elements of the mechanisms can be connected to establish a different power flow in accordance with engagement or release of frictional engagement devices under the control of servo hydraulic pressure to achieve plural speed stages. The system comprises a servo pressure feed line for feeding, even in a non-running range, servo hydraulic pressure to at least one particular device out of plural frictional engagement devices which are caused to simultaneously engage in a reverse range of the transmission, a directional control valve disposed in the line to control feed or drain of the servo hydraulic pressure to or from said particular device through the line, and a solenoid valve for controlling the control valve to prevent the feed of the servo hydraulic pressure at vehicle speeds above a predetermined value.

Abstract: A five-speed automatic transmission includes a main transmission and an over-drive transmission of a front disposition type. The main transmission includes three sets of planetary gears, a clutch for engaging and disengaging speed-change elements of the planetary gear sets, and a brake for fixing and releasing the speed change elements, and provides for four forward speed ranges and one reverse speed range. In the over-drive transmission of a front disposition type, a speed change element of an over-drive planetary gear set connected to an input element of the main transmission is adapted to be engaged, disengaged and fixed for achieving either a directly coupled stage or an over-drive stage. The over-drive transmission releases the direct coupling for reverse driving operation. One of the clutches of the main transmission for achieving the directly coupled stage and one of the brakes for achieving the low speed stage are engageable in the reverse driving operation.

Abstract: A shift control apparatus for an automatic transmission including a gear train having a plurality of one-way clutches having their engagement states switched in accordance with torque applying directions and a plurality of frictional engagement units adapted to be engaged by oil pressures. The apparatus comprises a controller for engaging a first one of the frictional engagement units so as to maintain a predetermined gear stage after any of the one-way clutches has been engaged or released, if a predetermined condition is satisfied after the one-way clutch has been engaged or released to start a shift to the predetermined gear stage.

Abstract: An apparatus for controlling a vehicle continuously variable transmission, including a directional control valve having a first spool movable between a shift-down and a shift-up position, a flow control valve including a second spool movable between a flow-restricting and a non-restricting position, and a first and a second solenoid-operated valve for applying an actuating pressure to the first and second spools. The directional and flow control valves and the solenoid-operated valves are adapted such that the first and second spools are moved toward the shift-up and flow restricting positions, respectively, when the actuating pressure is not applied to the spools, or when solenoid coils of the two solenoid-operated valves are both off. The directional control valve may have a shift-down chamber for receiving a pilot pressure to move the first spool to the shift-down position when a failure of one of the solenoid coils exists while the vehicle speed is lower than a predetermined limit.

Abstract: A vehicle transmission including a first, a second and a third planetary gear unit coaxially disposed between an input and an output member. The three units have respective first, second and third sun gears, respective first, second and third planetary gears, respective first, second and third carriers, and respective first, second and third ring gears. The first carrier, second ring gear, third sun gear and output members are connected to each other, while the second carrier and the third ring gear are connected to each other.

Abstract: A planetary gear type speed change device having a first planetary gear mechanism 10, 12, 14, 16 or 60, 64, 66, 68, 70 and a second planetary gear mechanism 20, 22, 24, 26 or 62, 64, 66, 70 incorporated between an input shaft 52 and an output shaft 54 by a selectively actuable drive system including four clutches 38, 40, 42, 44, two brakes 46, 48 and a one-way clutch 34, wherein the one-way clutch 34 has two functions of selectively braking the ring gear 12 or the carrier 70 with respect to the housing 50 via the brake 46 in providing a first speed stage and also of selectively connecting the carrier 26 or 70 with the sun gear 20 or 62 via the clutch 40 in providing a third speed stage.

Abstract: A rotating member such as a sprocket to be coupled with a shaft is formed with a fitting bore which extends on the center axis and opens at at least one of its axial end portions. The rotating member is arranged in and rotatably held by a case such that its fitting bore opens toward the outside of the case. The shaft is inserted into and coupled with the fitting bore held in the case such that it can rotate integrally with the rotating member. This rotating member is formed with an air communication portion for providing communication between the inside and outside of the fitting bore and equipped with a valve for opening or closing the air communication portion. The valve may be opened in response to the rise or drop in the internal pressure of a fitting bore, by the pressure of the shaft or by a centrifugal force. With the valve being closed, lubrication oil in the case is prevented from leaking.

Abstract: In an automatic transmission to provide a plurality of forward speed stages for a vehicle having a transversely mounted engine, a counter drive gear serving as a power output member of the speed change gear device to drive a counter shaft is positioned between a planetary gear mechanism of the speed change gear device and the torque converter, and the forward clutch which is engaged to provide a plurality of forward speed stages is positioned between the torque converter and the counter drive gear.

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