Patent ID: 8943818
Filing Date: 2015-02-03
Classification: F16H

Abstract:
1. A hydraulic device for a stepless transmission, the hydraulic device comprising: an engine-driven main pump and an engine-driven sub-pump; a main passage for connecting the main pump to a speed-changing hydraulic pressure circuit and a lubricating-hydraulic pressure circuit; a sub-passage for connecting the sub-pump to the lubricating-hydraulic pressure circuit; a regulator that opens when the hydraulic pressure of hydraulic oil supplied to the speed-changing hydraulic pressure circuit through the main passages increases, controls the amount of hydraulic oil supplied to the lubricating-hydraulic pressure circuit through the main passage and the sub-passage, and adjusts the hydraulic pressure of hydraulic oil supplied to the speed-changing hydraulic pressure circuit; a bypass passage for connecting, to each other, a section of the main passage located upstream of a location where the speed-changing hydraulic pressure circuit is connected and a section of the sub-passage located upstream of the regulator; a check valve that is provided in the bypass passage and permits only flow of hydraulic oil in a direction from the sub-passage toward the main passage, wherein the check valve closes when discharge performance of the main pump increases, and supply paths for hydraulic oil discharged from the sub-pump are automatically switched in accordance with the discharge performance of the main pump; and a switch-over valve provided at a section of the sub-passage located downstream of a location where the bypass passage is connected and located upstream of the regulator, and the switch-over valve is configured to be capable of being switched between a blocked state, where supply of hydraulic oil to a section of the sub-passage located downstream of the switch-over valve is blocked, and a communication state, where supply of hydraulic oil to the section of the sub-passage located downstream of the switch-over valve is permitted, wherein the switch-over valve is switched to the blocked state before the supply paths for hydraulic oil discharged from the sub-pump are automatically switched in accordance with the discharge performance of the main pump.