| 摘要 |
<p>PURPOSE:To prevent any power loss and cavitation of a speed control device for an actuator by adjusting the opening of a flow passage control valve correspondingly to the differential pressure in a low pressure side oil passage between the front and the rear of a direction control valve. CONSTITUTION:When an actuator 5 is put in regular rotation, an oil pressure selector valve 7 is placed in the right position due to a high-pressure side pilot oil pressure 11a, while the oil pressure in a low-pressure side oil passage 10 is transmitted to a pilot port 6 through an oil passage 12, selector valve 7, check valve 16 and an oil passage 13 in order. On the other hand, a pilot port 2 is always in communication with a return oil passage 3, and the opening of the flow control valve 1 is placed under increase and decrease adjustment correspondingly to the differential pressure between the low-pressure side oil passages 10 and 3 in the front and the rear of the direction selector valve 4, that is, correspondingly to flow of the actuator in said oil passages. Therefore, any power loss and cavitation of the speed control device for the actuator can be prevented.</p> |
