Hydraulic controller of speed changer

Abstract

A transmission comprises a continuously variable speed control mechanism 10, a drive cylinder chamber 14, a driven cylinder chamber 19 and drive and driven shift control valves 60 and 65, and the continuously variable speed control mechanism 10 includes a drive pulley 11, a driven pulley 16 and a metal V-belt 15. A hydraulic controller for this transmission comprises standard-value calculating means, oil-quantity calculating means and compensation-value calculating means. The standard-value calculating means calculates a standard-operation control value for setting a target control pressure necessary for executing a ratio change in accordance to a ratio-change request, and the oil-quantity calculating means calculates a quantity of oil to be charged and discharged to and from the pulley cylinder chambers for executing the ratio change in accordance to the ratio-change request. The compensation-value calculating means calculates a compensation control value to compensate the standard-operation control value on a basis of the quantity of oil charged and discharged, and the operation of the shift control valve is controlled by applying an operation control value that is obtained by compensating the standard-operation control value with the compensation control value.

Description

technical field [0001] The present invention relates to a hydraulic control device for controlling the supply and discharge hydraulic pressure of the working oil of the hydraulic actuator in a transmission operated by a hydraulic actuator, in particular to a transmission composed of a belt-type continuously variable transmission mechanism hydraulic control device. Background technique [0002] An automatic transmission is configured to transmit a rotational driving force from an engine (drive source) by changing the speed according to the engine throttle opening and the vehicle speed, and it is generally known that the speed change is controlled by a hydraulic actuator. As an example, there is an automatic transmission with a belt-type continuously variable transmission mechanism disclosed in Japanese Patent Application Laid-Open No. 62-63448. A variable speed control valve that controls the supply and discharge of working oil. [0003] In such an automatic transmission, w...

AI Technical Summary

Problems solved by technology

[0004] However, since the control current is set according to the operating characteristics of the shift control valve in a steady state in the past, there is a problem that the control at the time of shift transition tends to be incorrect.

This is because, when the gear is shifted, it becomes the control of supplying working oil to one of the driving and driven pulley cylinder chambers and discharging the working oil from the other to change the gear ratio. The hydraulic oil flows through the transmission control valve, and the flow force at this time acts on the transmission control valve, and the hydraulic pressure is controlled relative to the target pulley. The hydraulic pressure on the supply side decreases, while the hydraulic pressure on the discharge side increases, and the responsiveness of the transmission control decreases.

In addition, when the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil increases, and there is a problem that the responsiveness of the gear shift decreases.

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