Jatco Corporation

Midori Yamaguchi

Masahiro Yamamoto

Yoshihisa Kodama

Toshiji Iida

Makoto Sawada

Hiroyasu Tanaka

Shigeki Shimanaka

Tatsuo Wakahara

Toshiyuki Shibuya

Hisao Nobu

Fumito Shinohara

Tatsuya Ozone

Kouhei Wakida

Kenichi Mori

Kazutaka Adachi

Hiroki Iwasa

Yusuke Kimura

Shigeru Ishii

Hiroyuki Ashizawa

Masayuki Shimizu

Takuichiro Inoue

Tateki Jozaki

Masahiko Kikuchi

Yutaka Kaneko

Ken Okahara

Atsufumi Kobayashi

Takurou Kawasumi

Hironobu Waki

Hiroki Kumashiro

Takanori Aoki

Ryuuichi Furukawa

The controller performs shift control of the transmission such that an actual pressure of a primary pressure becomes an indicating pressure. The controller includes a phase advance compensator which performs advance compensation of the indicating pressure, and a setting unit which sets an indicating pressure on which the advance compensation is performed by the phase advance compensator as the indicating pressure, in accordance with at least one of a rotation speed of a primary pulley, an input torque to a secondary pulley, a speed ratio, or a changing rate.

Control device of continuously variable transmission and control method of continuously variable transmission

A control apparatus for an automatic transmission includes a control section having a target secondary pressure setting section configured to set a target secondary pressure within a strength limit of the belt, and an operation switching section configured to switch a shift operation from a normal speed to a high speed higher than the normal speed when a predetermined condition is satisfied. The control section is configured to control the secondary pressure regulating valve by a feedback control based on the target secondary pressure and the actual secondary pressure sensed by the hydraulic pressure sensor. The target secondary pressure setting section is configured to modify the target secondary pressure by adding a predetermined quantity when a correction initiation condition is satisfied, the condition initiation including a first condition that the shift operation is performed at a high speed by switching of the operation switching section.

Control apparatus for continuously-variable transmission of vehicle

A speed ratio change control device for a belt type continuously variable transmission calculates a maximum thrust that can be generated by the primary pulley on the basis of an upper limit value of the line pressure, calculates an upper limit value of a shift speed on the basis of the maximum thrust, and sets the target speed ratio on the basis of the upper limit value of the shift speed.

Speed ratio change control device and method for belt type continuously variable transmission

A control apparatus for an automatic transmission includes a control section having a normal control section configured to actuate the step motor at a first speed by using a feedback control including an integral control in accordance with the target pulley ratio and the actual pulley ratio, a high speed control section configured to actuate the step motor at a second speed higher than the first speed by an open loop control based on the target pulley ratio, a judgment section configured to judge whether there is a high speed operation request, and a switch section configured to select the normal control performed by the normal control section at a normal condition, and to switch to the high speed control when a switch start condition is satisfied, the switch start condition including a first condition that the judgment section judges there is the high speed operation request.

This invention is a speed ratio change control device for a belt type continuously variable transmission that a minimum generated pressure of the primary pressure is estimated on the basis of a displacement speed of the movable sheave of the primary pulley and an opening area of a drain side passage of the speed ratio change control valve (S), an upper limit value of a shift speed is calculated on the basis of the minimum generated pressure (S), and the target speed ratio is set on the basis of the upper limit value of the shift speed (S).

When a speed of a vehicle is less than 8 km/h, an upshift determination condition is established, an idle switch signal is turned off, and a downshift is detected, an operating speed of the step motor is limited. Thereby, since the operating speed of the step motor is limited even when the vehicle is rapidly decelerated and re-accelerated before a pulley ratio is returned to a lowest value Lo, a shift speed of the downshift performed in the re-acceleration is lowered, and no slippage occurs in a V-belt between pulleys.

Shift control system in belt-type continuously variable transmission

In hydraulic pressure control apparatus and method for a continuously variable transmission, a line pressure of the continuously variable transmission is developed with a working oil supplied from an oil pump as an original pressure, and a command pressure is set to develop a line pressure target value of the target value in such a manner that the command pressure is maintained at a predetermined small value for a constant time and, thereafter, the value of the command pressure is raised up to the target value when a shift range of the continuously variable transmission is switched from a neutral range to a running range, the command pressure being raised at a rate lower than a step input to suppress an overshoot developed in the actual line pressure.

Hydraulic pressure control apparatus and method for continuously variable transmission

A hydraulic control apparatus for an automatic transmission with a line pressure regulator valve operative to regulate an oil pressure produced by an oil pump and set a line pressure, the hydraulic control apparatus including a control unit outputting a first command for controlling the line pressure regulator valve to set the line pressure to a minimum value immediately after engine start, and a second command for controlling the line pressure regulator valve to set the line pressure to a target value in accordance with increase in engine speed. The control unit is programmed to set the target value of the line pressure to a value smaller than a maximum value of the line pressure and/or reduce a target speed of engine speed, upon start of the engine in a low temperature condition.

Hydraulic control apparatus and method for automatic transmission

A shift control system includes a belt-type continuously variable transmission (CVT) with primary and secondary pulleys, a shift actuator that regulates an oil pressure supplied to the primary or secondary pulley to vary an actual transmission ratio of the CVT, and a control unit that controls the shift actuator. The control unit sets a target transmission ratio in a first mode when a normal driving range is selected and in a second mode when an engine braking range is selected, drives the shift actuator to adjust the actual transmission ratio to the target transmission ratio, determines a delay time to delay the setting of the target transmission ratio in the second mode at the time of range switchover from the normal driving range to the engine braking range, and holds the target transmission ratio set in the first mode until the delay time has elapsed from the range switchover.

Shift control system, and control apparatus and method for belt-type continuously variable transmission

A V-belt continuously variable transmission includes a primary pulley and a secondary pulley. The primary pulley is connected to an input shaft and the secondary pulley is connected to an output shaft. A V-belt is wrapped around the primary and secondary pulleys. When a speed ratio is to be increased: (a) the oil pressure supplied to the primary pulley is set to an oil pressure necessary for ensuring a torque capacity of the V-belt and for maintaining the speed ratio; and (b) the oil pressure supplied to the secondary pulley is set to an oil pressure that is higher than the oil pressure necessary for ensuring the torque capacity of the V-belt and for maintaining the speed ratio, thereby attaining a target speed change speed.

V-belt continuously variable transmission

A belt type continuously variable transmission includes a primary pulley (), a secondary pulley (), a belt () wound around the primary pulley and secondary pulley; a sensor () for detecting a vehicle running state; and a controller (). The controller () is programmed to: set a final pulley ratio achieved by a shift of the pulley ratio of the primary and secondary pulleys, based on the vehicle running state, compute a primary steady oil pressure supplied to the primary pulley and a secondary steady oil pressure supplied to the secondary pulley based on an input torque inputted to the primary pulley and an actual pulley ratio, determine a target shift speed based on the final pulley ratio, compute a target stroke speed of the primary pulley and/or secondary pulley from the target shift speed, compute a target pulley rotation speed of the primary pulley, based on the vehicle running state, compute a transitional oil pressure correction amount which can attain the target shift speed, in response to the target pulley rotation speed and the target stroke speed, and set one of the oil pressure supplied to the primary pulley and the oil pressure supplied to the secondary pulley, to the sum of the steady oil pressure and the transitional oil pressure correction amount, so as to attain the final pulley ratio.

Belt type continuously variable transmission

A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve that compares a variable ASTP representing a step position of the step motor and a step position BSTP of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP&#x2260;BSTP is satisfied determines that a step-out has occurred on the step motor.

Speed change ratio control unit for continuously variable transmission

There is provided an oil pressure reduction rate restricting apparatus for a V-belt type continuously variable transmission, which is comprised of a reduction rate restricting section that calculates a reduction rate restricted secondary pressure and a reduction rate restricted primary pressure by restricting respective reduction rates of the target secondary pressure and the target primary pressure when the reduction rates of the target secondary pressure and the target primary pressure calculated by a target secondary pressure calculating section and a target primary pressure calculating section, respectively, are equal to or greater than respective predetermined values. The secondary pressure and the primary pressure are controlled based on the reduction rate restricted secondary pressure and the reduction rate restricted primary pressure whose reduction rates have been restricted such that the gradient thereof are small. This prevents the actual secondary pressure and primary pressure from undershooting the respective target pressures, and therefore prevents a shortage in torque capacity, which is caused by oil pressure decrease.

Oil pressure reduction rate restricting apparatus for V-belt type continuously variable transmission

In a V-belt type CVT, an actual-shift-ratio corresponding operated position of a step motor is calculated through conversion of an actual shift ratio expressed by the rotational-speed ratio between primary and secondary pulleys. A displacement amount is calculated between the actual-shift-ratio corresponding operated position of the step motor and an actual position thereof. A correction amount of the line pressure is calculated to reduce the displacement amount, and the line pressure is corrected in accordance therewith.

System and method of controlling line pressure for V-belt type continuously variable transmission

A belt type continuously variable transmission (CVT) () for a vehicle varies the speed ratio in accordance with the hydraulic pressure that is regulated via a hydraulic pressure regulating unit (). A sensor () detects a vehicle speed. A CVT controller () calculates a target hydraulic pressure that is supplied to the CVT () on the basis of a predetermined speed change schedule so that the speed ratio varies in the direction of up-shifting as the vehicle speed increases (S). The CVT controller () also determines whether or not a specified condition holds (S, S), and controls the hydraulic pressure regulating unit according to a target start-up hydraulic pressure which is larger than a target hydraulic pressure for normal running (S, S), thereby preventing a speed change lag when the vehicle starts to move.

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Yokohama, Japan

Midori Yamaguchi