Oil pressure control device for automatic transmission

Abstract

A control unit is provided such that, when engaging pressure is supplied to both of two working oil chambers to engage a prescribed engaging element and achieve a first speed level, and an engaging element other than the prescribed engaging element is clutched to shift speeds to a second speed level (step S1), the control unit reduces the supply of engaging pressure to one of the two working oil chambers to less than the supply when the first speed level is achieved (step S3).

Description

technical field [0001] The present invention relates to a hydraulic control device of an automatic transmission having a plurality of engagement elements mounted on a vehicle, and specifically relates to a dual-chamber hydraulic servo control device having a plurality of operating oil chambers for one engagement element. The oil pressure control device of the automatic transmission that engages or disengages the engaging member. Background technique [0002] Conventionally, a stepped automatic transmission mounted on a vehicle, for example, uses a hydraulic control device to control the engagement states of a plurality of engagement elements (clutches, brakes), and forms a transmission path in the transmission mechanism for each gear stage to realize multiple transmissions. Gear shift. In such a stepped automatic transmission and a hydraulic control device, a hydraulic servo is used in order to engage or disengage the engagement elements, and as the hydraulic servo, there i...

AI Technical Summary

Problems solved by technology

[0003] However, for example, in a multi-speed automatic transmission, in terms of the structure of the gear train, the torque of the engagement elements engaged in the first forward speed or the first reverse speed is shared with the engagement elements engaged in the shift speed other than the first forward speed or the first reverse speed. bigger than

Therefore, when the hydraulic pressure is supplied from the linear solenoid unit to the operating oil chamber of the engagement member engaged at the first forward speed or the first reverse speed, it is necessary to adjust the gain of the linear solenoid unit (the hydraulic pressure relative to the displacement amount of the current command value) Output displacement) is higher than when hydraulic pressure is supplied to the operating oil chamber of other engagement elements, which may lead to deterioration of the controllability of the engagement elements engaged in the first forward speed or the first reverse speed

In addition, since the torque sharing of the engagement elements engaged in the first forward speed or the first reverse speed is large, the supply pressure of the oil pump needs to be increased, so it becomes a design with a high load on the pump.

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