Oil pressure controller for automatic transmission

Abstract

Provided is an oil pressure controller for an automatic transmission in which, when a selection is switched from an N-range to a D-range, the instruction oil pressure for a starting clutch is quickly raised temporarily and then quickly lowered to create a precharge shelf pressure (Pa) for the start-off clutch, while the oil pressure is gradually raised from the drop point of the precharge shelf pressure (Pa) to create capacity adjustment pressures (Pb1) or (Pb2). The capacity adjustment pressures (Pb1, Pb2) are changed in response to an actuation state or non-actuation state of the brake, and the capacity adjustment pressure (Pb1) under the non-actuation state of the brake is higher than the adjustment pressure (Pb2) under the actuation state of the brake by an offset amount (Of). As a result, when the selection is switched from a neutral range to a traveling range, the selection shock of the start-off clutch when the brake is in an actuated state is reduced and starting off can be performed favorably under the non-actuation state of the brake.

Description

technical field [0001] The present invention relates to a hydraulic control device for an automatic transmission mounted on a vehicle, and more particularly to an oil for an automatic transmission that achieves both the reduction of the so-called selection vibration and the starting performance during the selection operation from neutral to driving. pressure control device. Background technique [0002] As such a technique, for example, the technique described in Patent Document 1 is proposed. In the hydraulic control device described in this patent document 1, a preload pressure regulating device is provided. The operating oil pressure rises sharply temporarily and then falls sharply to generate the frame pressure (shelf pressure) for preloading; the capacity regulating pressure regulator, which gradually increases the above operating oil pressure from the moment of the preloading pressure to generate Volume regulation pressure of friction coupling elements. [0003] Fur...

AI Technical Summary

Problems solved by technology

[0006] Therefore, in a situation where the driver requires startability, although the driver's sensitivity to gear selection vibration becomes low, the above-mentioned rack pressure and displacement adjustment pressure are hydraulic pressures that consider the gear selection vibration, so until the frictional engagement element is engaged So far, it takes time and leads to the deterioration of the starting performance

On the other hand, in an operating condition in which the sensitivity to startability becomes low, the above-mentioned rack pressure and capacity adjustment pressure are hydraulic pressures that take startability into consideration, so that vibration occurs when the frictional engagement element is engaged, causing discomfort to the driver. sense, not ideal

Images