HYDRAULIC CONTROL DEVICE

摘要

A first-type passage switching valve is provided in an oil supply line connecting a friction element to an N/H type pressure control valve and a second-type passage switching valve is provided in another oil supply line connecting another friction element to an N/L type pressure control valve. A working-pressure output valve outputs a hydraulic working pressure to each of the first-type and the second-type passage switching valves. The first-type passage switching valve changes its communication condition from a first communication state connecting the friction element and the pressure control valve with each other to a second communication state connecting the friction element and a drain side with each other, or vice versa. The second-type passage switching valve changes its communication condition from a first communication state connecting the friction element and the pressure control valve with each other to a third communication state connecting the friction element and a hydraulic pressure source with each other, or vice versa.

主权项

1. In an automatic transmission apparatus of a vehicle, which comprises;
multiple friction elements; and a hydraulic-pressure producing unit for outputting a line pressure of a high pressure; and a hydraulic control device for adjusting a hydraulic control pressure to be supplied to each of the friction elements by use of the line pressure, wherein the hydraulic control pressure is adjusted at a value between the line pressure and a drain pressure of a low pressure from a drain side, the hydraulic control device comprises; multiple hydraulic-pressure control units provided for each of the friction elements, each of the hydraulic-pressure control units being electrically controlled based on a command value for the hydraulic control pressure in order to adjust a hydraulic pressure of working oil to be outputted therefrom at the value between the line pressure and the drain pressure in accordance with an electric power supply amount and to output such an adjusted hydraulic pressure as the hydraulic control pressure, and each of the hydraulic-pressure control units outputting the line pressure when no electric power is supplied to the hydraulic-pressure control units; multiple oil supply lines provided for each of the friction elements, each of the oil supply lines connecting each of the hydraulic-pressure control units to the respective friction element in order to supply the hydraulic control pressure outputted from the hydraulic-pressure control units to the respective friction element; a passage switching unit of a first type provided in at least one of the oil supply lines to change a communication condition of the passage switching unit from a first communication state to a second communication state, or vice versa, wherein the friction element is communicated to the hydraulic-pressure control unit in the first communication state and the friction element is communicated to the drain side in the second communication state; and a hydraulic-pressure output unit for selecting one of the line pressure and the drain pressure depending an electric power supply condition thereto and outputting a selected hydraulic pressure as a hydraulic working pressure to the passage switching unit, wherein the passage switching unit has a first pressure receiving portion for receiving the hydraulic working pressure outputted from the hydraulic-pressure output unit and a second pressure receiving portion for receiving a clutch pressure of the friction element, which is a hydraulic pressure in the friction element, and wherein a pressure receiving condition at the first and the second pressure receiving portions is changed by controlling the electric power supply to the hydraulic-pressure output unit and/or the hydraulic-pressure control unit in order to change the communication condition of the passage switching unit from the first communication state to the second communication state, or vice versa.