| 摘要 |
In a cylinder control device comprising a control valve that controls a flow of working fluid flowing between a cylinder and a pump, the control valve includes a spool provided in a main body portion, a sleeve that is provided in the main body portion opposite each of two end portions of the spool, and includes a communicating port that communicates with a valve chamber, a communicating passage that communicates with a cylinder chamber, and a throttle passage that communicates with the cylinder chamber, a valve body provided in the sleeve to control a communication state between the communicating port and the communicating passage and throttle passage in accordance with a sliding position thereof, and a biasing member that biases the valve body in a valve closing direction. |
| 主权项 |
1. A cylinder control device comprising:
a cylinder driven by a fluid pressure of a working fluid in each of two cylinder chambers; a pump having two ports, the pump being configured to discharge the working fluid selectively from any of the two ports; and a control valve configured to control a flow of the working fluid, the working fluid flowing between the cylinder and the pump, wherein the control valve comprises: a main body portion; a spool slidably provided in the main body portion; sleeves provided in the main body portion so as to be respectively opposed to end portions of the spool, valve chambers being respectively defined between the sleeves and the end portions of the spool, the valve chambers being respectively connected to the ports, the sleeves having communicating ports respectively communicating with the valve chambers and supply/discharge ports respectively communicating with the cylinder chambers; valve bodies respectively provided in the sleeves slidably, each of the valve bodies being configured to control a communication state between the communicating port and the supply/discharge port in accordance with a sliding position thereof; and biasing members configured to respectively bias the valve bodies in a direction for closing the corresponding communicating port, wherein, when the pump does not discharge the working fluid, the two valve bodies respectively close the communicating ports in response to biasing forces of the biasing members so that communication between the valve chambers and the cylinder chambers is respectively blocked, and wherein, when the pump discharges the working fluid into one of the valve chambers from one of the ports,
one of the valve bodies is moved against the biasing force of the corresponding biasing member by means of the fluid pressure in the one valve chamber so as to allow the working fluid to flow from the one valve chamber toward one of the cylinder chambers through one of the supply/discharge ports, andthe other valve body is pushed by the spool and is moved against the biasing force of the corresponding biasing member so that a larger resistance than a resistance applied to the working fluid passing through the one supply/discharge port is applied to the working fluid passing through the other supply/discharge port to allow the working fluid to flow from the other cylinder chamber toward the other valve chamber through the other supply/discharge port, the spool being moved by the fluid pressure in the one valve chamber. |
