Toyota Jidosha Kabushiki Kaisha

Aisin Aw Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Aisin Seiki Kabushiki Kaisha

Teruo Akashi

Hiroshi Ito

Shigemichi Yamada

Kazuaki Watanabe

Yasunari Nakamura

Isamu Minemoto

Seitoku Kubo

Hiroshi Itoh

Mitsuru Takada

Yukio Terakura

Takenori Kano

Fumitomo Yokoyama

Kojiro Kuramochi

Masaharu Tanaka

Tatsuya Iwatsuki

Kenichi Kikuchi

Yoshinobu Iwase

Kiyoshi Taniyama

Shiro Sonoda

Shinjiro Hayashi

A hydraulic control apparatus for an automatic transmission having a mechanical parking mechanism includes a manual valve disposed in the hydraulic control apparatus and having a parking (P) position, reverse (R) position, neutral (N) position and at least one forward speed position. The manual valve is provided with a drain port for releasing, in the parking position, the hydraulic pressure of a hydraulic circuit which establishes the reverse range, and the drain port is provided with an orifice which limits the discharge rate of hydraulic pressure.

Hydraulic control apparatus for automatic transmissions

A method and an apparatus for controlling a 4-wheel drive system of a motor vehicle having front wheels and rear wheels and a power transmission. The 4-wheel drive system includes a differential control clutch having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels. When it is determined that the power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of the first gear position, the differential control clutch is temporarily placed in a fully disengaged position thereof for a predetermined time duration. With the clutch placed in the fully disengaged position upon each shifting operation of the transmission to the second gear position, the separated friction surfaces of the clutch may be lubricated to maintain high durability of the clutch.

Method and apparatus for controlling 4-wheel drive system for a motor

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. In the case of the manual valve being shifted to a low speed position, then from the low speed port of the manual valve, the line pressure is applied to a modulator valve where the line pressure is modulated, and applied to a back pressure port of a primary regulator valve to boost the line pressure up to certain volume.

Power transmission device for four wheel drive vehicles

A hydraulic control system for a continuously variable transmission having a cylinder for changing the effective diameter of a pulley to control a speed ratio of the transmission. The control system comprises a spool valve assembly communicating with the cylinder to control the supply and discharge flows of a fluid to and from the cylinder. The valve assembly comprises a shift-speed control valve unit for controlling a rate of variation in the speed ratio of the transmission. The shift-speed control valve unit has only two discharge ports associated with the fluid discharge from the cylinder. The shift-speed control valve unit may take the form of a spool valve having a spool axially movable to open and close the ports to permit and restrict the fluid flows through supply and discharge conduits communicating with the ports and the cylinder. The spool may only partially open the corresponding port to permit the fluid flow therethrough for supplying or discharging the fluid. The valve assembly may comprise a shift-direction switching valve unit for changing the direction in which the speed ratio is varied. The switching valve unit has only two discharge ports associated with the fluid discharge from the cylinder.

Spool-type control valve assembly with reduced spool stroke for

A method is described for controlling a vehicle transmission mechanism which incorporates several selectively engagable power transmission systems each being selectively individually connectable between a first member and a second member for transmitting rotational power between them, with each such power transmission system including a clutching mechanism which can be selectively controlled either to freewheel in both rotational directions or to provide direct transmission of rotational power in one rotational direction only and to freewheel in the other rotational direction. While a first one of the power transmission systems which is for providing a certain speed stage is connected between the first member and the second member for transmitting rotational power between them at a gearing ratio appropriate to that speed stage, a second one of the power transmission systems which is for providing the speed stage one lower than that certain speed stage is also individually connected in parallel with the first power transmission system, with the particular clutching mechanism associated with the second power transmission system being controlled to be able to provide direct transmission of rotational power in one rotational direction only and to freewheel in the other rotational direction. Thus, the clutching mechanism of the second power transmission system freewheels. When a downshift is required, the clutching mechanism of the first power transmission system is disengaged, and the second power transmission system takes over the power transmission. A device for practicing this method is also described.

Transmission and transmission control device for providing downshifting

A method for controlling a vehicle transmission mechanism which incorporates several selectively engageable power transmission systems each being selectively individually connectable between a first member and a second member for transmitting rotational power between them, with each such power transmission system including a clutching mechanism which can be selectively controlled either to freewheel in both rotational directions or to provide direct transmission of rotational power in one rotational direction only and to freewheel in the other rotational direction. While a first one of the power transmission systems which is for providing a certain speed stage is connected between the first member and the second member for transmitting rotational power between them at a gearing ratio appropriate to that certain speed stage, a second one of the power transmission systems which is for providing a speed stage one higher or lower than that certain speed stage is also connected in parallel with the first power transmission system between the first member and the second member, with the clutching mechanism associated with the one of these power transmission systems which provides the lower speed stage being controlled to be able to provide direct transmission of rotational power in one rotational direction only and to freewheel in the other rotational direction. Thus, this clutching mechanism of the lower speed stage power transmission system freewheels. Thereby, smooth and snappy speed stage shifting is made available. A device for practicing this method is also described.

Transmission control method providing overlapped engagement of power

An actuation system for a transmission synchronizer, including a first member and a second member, the second member being pressed against the first member for synchronization of two relatively rotating elements, includes a variable pressure type actuator which selectively presses the second member against the first member, with a pressing force which is controllable to vary over a range so as to press the second member against the first member at a lower pressure in the initial phase of synchronization and at a substantially increased pressure at the end of synchronization.

Actuation system for transmission synchronizer providing regulated

A power supplying member supplies rotational power in a certain rotational direction to an input member of the transmission, and a power receiving member takes out power from a driven gear wheel shaft. Two driving gear wheel shafts extend parallel to the driven gear wheel shaft. First and second driving gear wheels are respectively rotatably mounted on the first and the second driving gear wheel shaft and meshed with a common driven gear wheel fixedly mounted on the driven gear wheel shaft. First and second synchromesh devices respectively selectively engage the first and the second driving gear wheel to the first and the second driving gear wheel shaft. First and second clutching mechanisms, each of which either can be disconnected so as to freewheel in both rotational directions or can be connected in the one rotational direction which is required for transmission of power through that clutching mechanism from the power supplying member rotating in the certain rotational direction so as to function as a one way clutch, are mounted to selectively transmit rotational power between the input member and the first and second driving gear wheel shafts respectively, both proximate to ends of the first and second driving gear wheel shafts closer to the input member.

Transmission with two parallel driving shafts bearing two driving gears

A power supplying member supplies rotational power in a certain rotational direction to a first member of the transmission, and a power receiving member takes out power from a second member. Several power transmission systems are provided between the first and the second member, which are selectively engageable so as to provide various speed stages between them. Each power transmission system has a clutching mechanism which either can be disconnected so as to freewheel in both rotational directions, or can be connected only in the one rotational direction which is required for transmission of power through that power transmission system, so as to function as a one way clutch. Thus shifting between the speed stages does not require delicate controlling of the clutching mechanisms. At least one of these clutching mechanisms can also be locked up so as to transmit rotational power in both rotational directions, and this enables engine braking to be made available, when the transmission is mounted in an automotive vehicle.

Transmission mechanism with parallel transmission systems including one

A power supplying member supplies rotational power in a certain rotational direction to an input member of the transmission, and a power receiving member takes out power from a driven gear wheel shaft. Two driving gear wheels shafts extend parallel to the driven gear wheel shaft. First and second pairs of gear wheels and first and second synchromesh devices are provided, one of each pair of gear wheels being mounted on the corresponding one of the driving gear wheel shafts and the other being mounted on the driven gear wheel shaft, and one of each pair of gear wheels being rotatably mounted on its gear wheel shaft and being selectively engaged thereto by the corresponding one of the synchromesh devices, while the other one of that pair of gear wheels is fixedly mounted on its gear wheel shaft. First and second clutching mechanisms, each of which either can be disconnected so as to freewheel in both rotational directions or can be connected in the one rotational direction which is required for transmission of power through that clutching mechanism from the power supplying member rotating in the certain rotational direction so as to function as a one-way clutch, are mounted to selectively transmit rotational power between the input member and the first and second driving gear wheel shafts respectively, both proximate to ends of the first and second driving gear wheel shafts that are closest to the input member.

Transmission with driven shaft and two clutching devices at the same

A power supplying member supplies rotational power in a certain rotational direction to a first member of the transmission, and a power receiving member takes out power from a second member. Several power transmission systems are provided between the first and the second member, which are selectively engagable so as to provide various speed stages between them. Each power transmission system has a clutching mechanism which either can be disconnected so as to freewheel in both rotational directions, or can be connected to transmit rotational power at least in the one rotational direction which is required for transmission of power through that power transmission system from the first member to the second member. A fluid torque converter is provided in the rotational power transmission path of only one of the power transmission systems which provides the lowest gearing ratio between the first member and the second member.

Transmission mechanism with parallel transmission systems including

A vibration damping device for a mechanical clutch release system comprising a damper weight mounted to an inner cable connected to a release fork by a clevis. The damper weight is provided with an axial bore for receiving the inner cable, two slits formed on diametrically opposite sides of the axial bore, a bolt for securely holding the inner cable in the axial bore and a cylindrical portion provided near the release fork to coaxially encircle the clevis.

Vibration damping device for a mechanical clutch release system

A gear means of an automatic transmission for automobiles including a planetary gear means and friction engaging means in combination, a carrier of the planetary gear means being integrally combined with one of two relatively rotatable elements of the friction engaging means to provide an integral carrier assembly which in turn provides a planetary assembly by incorporating planetary pinions, wherein a rotary mass unbalance of the planetary assembly due to an asymmetrical arrangement of planetary pinions is compensated for by removing a part of the one of the two relatively rotatable elements forming a part of the carrier assembly.

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Toyota, Japan

Teruo Akashi