Jatco Corporation

Nissan Motor Company Limited

Katsumi Doihara

Yoshihisa Kodama

Yasuaki Yoshikawa

Kiyotaka Sawano

Hidemasa Kawaguchi

Kenta Nakamura

Masahiro Nishi

Keisuke Koyama

Hiroyasu Tanaka

Yusuke Kimura

Masahiro Yamamoto

Shigeki Shimanaka

Tatsuo Ochiai

Hideshi Wakayama

Makoto Sawada

Hirofumi Okahara

Koji Dohi

Tomoyuki Mizuochi

Azusa Shimoda

Hironobu Waki

Yoshichika Hagiwara

Naohiro Hoshi

Tatsuya Ozone

Shoichi Sekiguchi

Hideaki Sasaki

Toshio Saitou

A control method for a belt-type continuously variable transmission is provided for performing a belt slip control. The method includes oscillating hydraulic pressure and monitoring a phase difference calculated based on a multiplication value of an oscillation component in an actual hydraulic pressure and an oscillation component in an actual variable speed ratio to estimate a belt slip condition. The method further includes controlling hydraulic pressure to maintain a predetermined belt slip condition by reducing the hydraulic pressure to be lower than a hydraulic pressure in a normal control time based on an estimation, and limiting an input torque-change rate in which an input torque to the belt-type continuously variable transmission changes in an increasing direction until the hydraulic pressure rises to a hydraulic pressure in which the input torque is not excessive relative to a belt clamp force.

Controller and control method of belt-type continuously variable transmission

A control device for a belt type continuously variable transmission device includes primary And secondary pulleys and a belt and controls gear ratio based on a running radius of the belt on a pulley by controlling primary and secondary oil pressures. The transmission includes a belt slip control unit and a belt slip control permission determining unit. The belt slip control unit performs such control as to oscillate the secondary oil pressure, estimates a belt slip condition by monitoring the phase difference between an oscillation component included in an actual secondary oil pressure and an oscillation component included in an actual gear ration, and then reduces the actual secondary oil pressure to maintain a predetermined belt slip condition. The belt slip control permission determining unit permits belt slip control when a transmission rate as a change rate of the gear ratio is less than a predetermined value.

Controller and control method of belt type continuously variable transmission

A control device controls a belt type continuously variable transmission including a belt slip controller and a belt slip control permission determining unit. The device decreases belt friction when an estimated accuracy of a belt slip condition is high and prevents a belt from greatly slipping when an estimated accuracy is low. The device includes primary and secondary pulleys and the belt, and controls a gear ratio based on a running radius of the belt on a pulley by controlling primary and secondary oil pressures. The controller oscillates a secondary oil pressure, estimates the belt slip condition by monitoring a phase difference between oscillation components, and reduces an actual secondary oil pressure to maintain a predetermined belt slip condition. The determining unit permits belt slip control when a torque change speed input to the transmission mechanism is less than a predetermined value.

A control device controls a belt type continuously variable transmission including a primary pulley, a secondary pulley, and a belt, and controls a gear ratio based on a primary oil pressure and a secondary oil pressure. The control device includes a belt slip controller which oscillates the secondary oil pressure and monitors a phase difference between an oscillation component included in an actual secondary oil pressure and an oscillation component included in an actual gear ratio to estimate a belt slip state. The controller controls the actual secondary oil pressure to decrease based on the estimation to maintain a predetermined belt slip state. An oscillation amplitude setter sets an oscillation amplitude of the secondary hydraulic pressure small when the gear ratio is high compared with when the gear ratio is low, in a case of oscillating the secondary hydraulic pressure in the belt slip control.

A belt type continuously variable transmission mechanism has a primary pulley, a secondary pulley, and a belt, and a secondary hydraulic pressure controller to determine command secondary hydraulic pressure by feedback control based on the deviation between target secondary hydraulic pressure and actual hydraulic pressure, and control the secondary hydraulic pressure to the secondary pulley. The belt type continuously variable transmission mechanism further includes a belt slip control device to estimate a belt slip condition by monitoring the phase difference between an oscillation component included in the actual secondary hydraulic pressure and an oscillation component included in the actual transmission gear ratio and control the actual secondary hydraulic pressure to decrease based on the estimation so that a predetermined belt slip condition is maintained. The secondary hydraulic pressure control unit aborts feedback control of the secondary hydraulic pressure during belt slip control and controls the secondary hydraulic pressure by open control.

Belt-based, continuously-variable transmission control device and control method

A hydraulic pressure control device is provided that that controls hydraulic pressure of a clutch supplying torque to a continuously variable transmission while the vehicle is stopped and in a running range. The hydraulic pressure control device has an control section that estimates a clutch engagement hydraulic pressure for changing the clutch from an engaged state to a disengaged state based the hydraulic fluid pressure acting on the clutch during the stopping of the rotational movement of a primary pulley of the continuously variable transmission, and then controls regulation of the hydraulic pressure to the clutch from an engaged state to a disengaged state, when the vehicle is stopped and in the running range, so that the torque from the engine does not rotate a secondary pulley of the continuously variable transmission.

Hydraulic pressure control device for continuously variable transmission

A system for controlling a V-belt type CVT is constructed to change a first position of a step motor to a second position of the step motor corresponding to a second target shift ratio if it is determined that the primary-pulley pressure fails to reach a predetermined value. The second target shift ratio is on the high-speed side with respect to a third position of the step motor corresponding to a third target shift ratio to be achieved if it is determined that the primary-pulley pressure reaches the predetermined value.

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

CVT control unit of a belt CVT checks whether a reverse rotation of pulleys is generated. When the reverse rotation is generated, a PLpri torque capacity is calculated from a primary pressure Ppri, and this PLpri torque capacity is used as a torque limit value of a torque-down control of an engine control unit. An input torque to a transmission mechanism is compared with the PLpri torque capacity, and when the input torque exceeds the PLpri torque capacity, shortage of the PLpri torque capacity for the input torque is calculated. Then, this shortage is added to the input torque as a correction amount, and a line pressure is set on the basis of a result of this addition.

System for preventing belt slip of belt-type continuously variable transmission

A clutch engagement control device controls the engagement of a forward clutch () and reverse clutch () in an automatic transmission connected to an engine () in a vehicle. An inhibitor switch () outputs a range signal in accordance with a position range of a select lever (). A manual valve () supplies oil pressure selectively to one of the forward clutch () and the reverse clutch () by changing position in accordance with the position range of the select lever (). A controller () of the clutch engagement control device determines whether an unmatching range condition occurs in which the range of the select lever () indicated by the range signal and the range of the manual valve () do not match, when the range of the select lever () indicated by the range signal is a drive range or reverse range; and suppress an increase in engine rotation speed prior to engagement of the forward clutch or reverse clutch when the unmatching range condition occurs.

Growing community of inventors

Fuji, Japan

Katsumi Doihara