Aisin Aw Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Aisin-warner Kabushiki Kaisha

Aisin Aw Kabushiki Kaisha

Takahiro Yamashita

Yoshiharu Harada

Yutaka Taga

Kazumasa Tsukamoto

Yasuo Hojo

Takao Taniguchi

Yoichi Hayakawa

Akira Hoshino

Naoyuki Fukaya

Kazuaki Watanabe

Yoshikazu Sakaguchi

Koji Noda

Shinichi Matsui

Jiro Nishiwaki

Mitsuhiko Ando

Osamu Takeuchi

Takuji Taniguchi

Hiroshi Suzuki

A control system for an automatic transmission includes a clutch for transmitting the rotation of a fluid transmission unit to a speed change mechanism of a transmission and a hydraulic servo for applying/releasing the clutch. A stop state detector is provided for detecting the stop state of the vehicle. A release control oil pressure changer lowers the oil pressure of the hydraulic servo by a first set pressure when the vehicle stop state is detected. An in-neutral control oil pressure changer raises the oil pressure of the hydraulic servo by a second set pressure, when the difference between the input side RPM and the output side RPM of the fluid transmission unit has not changed, and lowers the same by a third set pressure when the rotational speed difference has changed. The first set pressure is different from the second and third set pressures.

Control system for automatic transmission

A control system for an automatic transmission having a hydraulic power transmission for transmitting the rotation of an engine to a gear shifter; a clutch to be applied, when a forward drive range is selected, for connecting the hydraulic power transmission and the gear shifter to one another; a one-way clutch to be locked, when the clutch is applied, for establishing a first forward speed of the gear shifter; a brake for locking the one-way clutch, when applied, to block the backward rotation of the output shaft of the gear shifter; a first hydraulic servo for applying the clutch when fed with an oil pressure; a second hydraulic servo for applying the brake when fed with an oil pressure; a stopping state detector that detects the stopping state of a vehicle by determining the vehicle speed is substantially 0, the accelerator pedal is in a released state and the foot brake pedal is depressed; a gradient detector that detects the gradient load of an uphill, as applied to the vehicle; and a controller that controls the oil pressure to be fed to the first and second hydraulic servos on the basis of the signals from the stopping state detector and the gradient detector. The controller includes a decision maker that determines whether the road is uphill, on the basis of the signal from the gradient detector; a pressure reducing device that reduces the oil pressure to be fed to the first hydraulic servo, to bring the clutch into a substantially released state; a feed device that feeds an oil pressure, as regulated on the basis of the gradient detector, to the second hydraulic servo, to apply the brake at an engaging extent according to the gradient load; and a device for executing the reduction of the feed oil pressure to the first hydraulic servo by the pressure reducer and the feed of the regulated oil pressure to the second hydraulic servo by the oil pressure feeder, if it is detected by the stopping state detector that the vehicle is in the stopping state and if it is determined by the decision maker that the road is uphill.

Hill holding brake pressure as a function of hill gradient detected as a

A control system for use with an electronically-controlled automatic transmission provides for accurate determination of a full stop of a vehicle. The control system includes a device for computing the vehicle speed on the basis of a signal from a vehicle speed sensor, a device for determining whether or not the brake pedal is depressed, a device for computing deceleration from a first predetermined vehicle speed to a second predetermined, extremely low vehicle speed when the brake has been determined to be depressed, and a device for determining an estimated vehicle stop time starting with detection of the extremely low vehicle speed and ending with full stop of the vehicle, the estimated vehicle stop time corresponding to the above-computed deceleration.

Determination of full stop in an electronically-controlled automatic

An automatic transmission with a reverse inhibit feedback passage between front and rear oil sumps. The transmission includes a case, a passage in the case for returning oil to the front sump from the rear sump and a flap valve for allowing the flow from rear sump to front sump while inhibiting oil flow in the reverse direction.

Automatic transmission with feedback passage for preventing reverse flow

A transfer portion connected to the output shaft of a transmission portion has a front planetary gear unit the output element of which is connected to the front wheels and a rear planetary gear unit the output element of which is connected to the rear wheels, the two units being connected to each other by a common element. The output shaft of the transmission portion is directly connected to the input element of either of the planetary gear units, while the same is connected to the input element of the other planetary gear unit via a clutch C.sub.3. Furthermore, the input element of the other planetary gear unit is connected to the case via a brake B.sub.4. Therefore, the reduction function can be realized in cooperation with the two planetary gear units. As a result, the four-wheel drive device is lightened. Furthermore, since the differential gear device is constituted by the planetary gear unit, a compact and light four-wheel drive device can be provided and the neutral state can be created by completely freeing the front and the rear wheels.

Four-wheel drive device

A lubrication system is provided for a transmission mechanism supported on input and output shafts, and a chain drive rotatably connects these shafts. The chain and drive elements on the shafts are provided with a casing for isolating the mechanism, which collects an oil bath within the bottom of the transmission casing for lubricating a chain or other transmission member. An oil pump supplies oil from a reservoir to various areas to be specifically lubricated within the transmission. Feed means associated with the oil pump regulates the level of the transmission oil bath. The system may additionally contain an oil strainer, an external cooler, a relief valve to limit the pressure from the oil pump, or various combinations of such elements. The various points of lubrication within the casing, in turn, drain into the casing. Oil level within the transmission casing is regulated to keep the level low and at the same time to maintain sufficient oil for lubricating the chain.

Lubricating structure for transmission mechanism

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Nishio, Japan

Takahiro Yamashita