Nissan Motor Company Limited

Jatco Corporation

Masahiro Nishi

Yoshihisa Kodama

Katsumi Doihara

Yasuaki Yoshikawa

Kiyotaka Sawano

Hidemasa Kawaguchi

Kenta Nakamura

Keisuke Koyama

Tomoyuki Mizuochi

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.

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Fuji, Japan

Masahiro Nishi