Patent ID: 9422951
Filing Date: 2016-08-23
CPC Classification: F15B,F16H

Claim Text:
1. A hydraulic circuit, comprising: a first circuit section, which has an accumulator for storing hydraulic pressure, and a control valve for opening and closing a passage for delivering hydraulic fluid from the accumulator to a predetermined actuator; an oil pump that delivers the hydraulic fluid to the accumulator; a second circuit section to which the hydraulic fluid discharged from the oil pump is delivered continuously; and a first filter that removes contaminants finer than those contained in the hydraulic fluid to be delivered to the second circuit section from the hydraulic fluid to be delivered to the accumulator; wherein the first filter is disposed on another passage for delivering the hydraulic fluid to the accumulator branched off from a passage for delivering the hydraulic fluid from the oil pump to the second circuit section; wherein the control valve includes a feeding valve that opens and closes the passage for delivering hydraulic fluid from the accumulator to the actuator, and a drain valve that withdraws the hydraulic fluid from the actuator; wherein the feeding valve and the drain valve are adapted to close a port thereof by pushing a valve element onto a valve seat; wherein the actuator includes a hydraulic chamber of an automatic transmission adapted to vary a speed ratio by delivering the hydraulic fluid thereto and withdrawing the hydraulic fluid therefrom; wherein hydraulic pressure higher than that in the second circuit section is stored in the accumulator; wherein the actuator includes a hydraulic chamber for controlling speed ratio that narrows a belt groove to increase an effective diameter of a belt by delivering the hydraulic fluid thereto, and a hydraulic chamber for controlling a belt clamping pressure that increases the belt clamping pressure by delivering the hydraulic fluid thereto; wherein the second circuit section includes a lubrication point that is continuously lubricated by the hydraulic fluid delivered from the oil pump; wherein the hydraulic circuit further comprises a second filter that removes contaminants from the hydraulic fluid passing therethrough that is discharged from the oil pump or sucked by the oil pump; and wherein a mesh size of the first filter is finer than that of the second filter.