RU1800144C - Hydraulic drive of bulldozer blade - Google Patents

Abstract

Usage: in hydraulic drive devices designed to control executive bodies, for example, a dozer blade. The inventive hydraulic actuator contains a tank 6, a pump 3, a spool 5, balanced by springs located in the control cavities A and B, throttles 13, overflow valves 14-16, the main 7 and 8 and additional 17-20 check valves, safety valves with remote unloading 11 and 12, as well as the hydraulic cylinder 1. The unloading pressure of the safety valves 11 and 12 should be less than the pressure created in the control cavities A and B by the overflow valves 14, 15 and 16. 1 il.

Description

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FIELD OF THE INVENTION This invention relates to hydraulic drive devices for controlling actuators, for example, a dozer blade.

An object of the invention is to enhance functionality and increase reliability.

The drawing shows a schematic diagram of a hydraulic actuator.

The hydraulic drive for controlling the dozer blade contains a hydraulic cylinder 1, the cavities of which are connected with the pressure line 2 of the pump 3 through a three-position valve 4. The valve 4 has a spring-loaded spool 5 and control cavities A and B. The cavities of the hydraulic cylinder 1 are in communication with the tank 6 through the check valves 7 and 8. The hydraulic actuator also contains drain lines 9 and 10 and safety valves 11 and 12 with remote unloading. The hydraulic actuator is equipped with throttles 13, through which the pressure line 2 of the pump 3 is connected to the control cavities A and B of the three-position distributor 4. The hydraulic actuator is equipped with overflow valves 14 and 15, through which the control cavities A and B of the three-position distributor 4 are connected to the tank B. and an overflow valve 16 through which in the neutral position of the distributor 4 the pressure line 2 of the pump is in communication with the tank 6. The hydraulic actuator is also equipped with additional check valves 17-20. The control cavities A and B of the distributor 4 are in communication with the drain and E 9 and 10, which are mounted respectively in series additional check valves 19,17 and the relief valves 11 and 12 with remote emptying. The cylinder cavities through other additional non-return valves 18.20 are connected to the corresponding drain lines 10.9 between the first additional non-return valves 17.19 and the corresponding safety valves 11 and 12 with remote unloading.

The hydraulic actuator operates as follows.

1. Lowering the blade. Safety valve 12 is included for unloading. There is a pressure drop in the control cavity B below the settings of the overflow valves 14, 15 and 16. As a result of an unbalanced force from the side of the cavity A, the spool 5 moves to the leftmost position, thereby opening up the working pressure to the rodless cavity of the hydraulic cylinder 1. Drain from the stock cavity occurs

through the check valve 18 and the unloaded safety valve 12.

2. Fixed blade position. Safety valves 11 and 12 are turned on for operating pressure. Spool 5 is in the middle position. The liquid from the pump 3 enters the drain through the overflow valve 16. The pressure of the safety valves 11 and 12 is maintained in the cavities of the hydraulic cylinder. When a vacuum occurs in these cavities, the check valves 7 and 8 are actuated.

3. The float position of the blade is effected by simultaneously activating the safety valves 11 and 12 for unloading. Both cavities of the hydraulic cylinder are connected to the drain via additional check and safety valves. Since the pressure drop in the cavities A and B

occurs simultaneously, the spool remains in the middle position and the pump is unloaded through the overflow valve 16.

4. The blade is lifted by turning on relief valve 11 for unloading.

Claims (1)

SUMMARY OF THE INVENTION A hydraulic drive for controlling a dozer blade, comprising a hydraulic cylinder, the cavities of which are connected to the pressure line of the pump through a three-position valve having a spring-loaded spool and control cavities, and with the tank through check valves, drain lines, and safety valves with remote unloading, characterized in that in order to expand the functionality and increase reliability, it it is equipped with throttles through which the pressure line of the pump is in communication with the control cavities of the three-position distributor, overflow valves through which are connected with the cavity tank control the three-way valve and in the neutral position of the latter - the pressure line of the pump, and additional check valves, and the control cavity of the three-position distributor communicated with drain lines in which one of the additional check valves and safety valves with remote unloading are installed in series, while the hydraulic cylinder cavity through other additional non-return valves are connected to the respective drain lines between the first additional non-return valves remote control valves and safety valves.