HYDRAULIC CIRCUIT FOR AN ACTUATOR

摘要

A hydraulic circuit includes a first oil passage communicating with a first port of an actuator and a second oil passage communicating with a second port of the actuator. A lower portion-communicating oil passage or oil discharge passage communicates with an oil tank. A first valve is provided between the first oil passage and the lower portion-communicating oil passage or oil discharge passage. The first valve is capable of allowing the first oil passage to communicate with the lower portion-communicating oil passage or the oil discharge passage when a pressure of the first oil passage reaches a predetermined value or higher. A second valve is located in a vicinity of the first valve and between the second oil passage and the lower portion-communicating oil passage or the oil discharge passage.

主权项

1. A hydraulic circuit comprising:
a first oil passage communicating with a first port of an actuator; a second oil passage communicating with a second port of the actuator; at least one oil-discharging passage communicating with an oil tank; a first valve arranged between the first oil passage and the oil-discharging passage; and a second valve arranged in a vicinity of the first valve and between the second oil passage and the discharge passage, wherein the first and second valves have the following modes of operation:
a mode wherein, when a pressure of the second oil passage drops to a predetermined value or lower, the second valve allows hydraulic oil to flow into the oil-discharging passage from the second oil passage, whereby the second oil passage and the oil-discharging passage are in fluid communication with one another, anda mode wherein, when a pressure of the first oil passage reaches a predetermined value or higher, the first valve allows hydraulic oil to flow into the oil-discharging passage from the from the first oil passage, whereby the first oil passage and the oil-discharging passage are in fluid communication with one another.