Motor control loop and control valve

Abstract

The invention discloses a control valve, which is provided with a first port (10A), a second port (10B) and an oil return port (10T) and comprises a controller. The controller is used for acquiring pressure of oil supplied to the first port, cutting off an oil path between the first port and the second port if oil supply pressure is lower than the acquired pressure, and closing the oil path between the first port and the second port if the oil supply pressure is equal to the acquired pressure approximately when oil is supplied to the first port again. The invention further discloses a motor control loop, which comprises a motor (1), a brake (2) and a shuttle valve (3), the brake (2) is connected with the motor, two working oil paths of the motor are communicated with two inlets of the shuttle valve, an outlet of the shuttle valve is communicated with a control port of the brake, and the control valve is connected between the working oil paths and the inlets of the shuttle valve. The control valve arranged in the motor control loop can prevent the motor from reversing and slipping when in secondary hoisting, and accordingly safety performance is improved.

Description

technical field [0001] The present invention relates to the field of hydraulic control, more specifically, to a motor control circuit and a control valve. Background technique [0002] like figure 1 As shown, the existing motor control circuit includes a motor 1, a brake 2 connected to the motor 1, and a shuttle valve 3. The two working oil circuits of the motor 1 are connected to the two working oil ports A and B of the control valve. The two working oil passages communicate with the two inlets of the shuttle valve 3 respectively, and the outlet of the shuttle valve 3 communicates with the control port of the brake 2 . Therefore, when any working oil circuit of the motor 1 supplies oil to the motor 1 to make the motor 1 rotate, the pressure of the working oil circuit communicates with the control port of the brake 2 through the shuttle valve 3, so that the brake 2 is opened, so that the motor 1 can smoothly turn. When the motor 1 stops, the pressure in the two working oi...

AI Technical Summary

Problems solved by technology

[0003] In the motor control circuit as described above, when the hoisting mechanism is hoisted for the first time, oil enters the first working oil port A, and the hydraulic oil passes through the shuttle valve 3 to open the brake 2. When the load is not completely off the ground, the second The working pressure of the first working oil port A changes with the load. When the working pressure of the first working oil port A is high enough to drive the winch motor 1 to lift the load, the winch motor 1 drives the load to start lifting, and the load rises to a certain height , the first working oil port A stops oil intake, the brake 2 is closed, and the hoisting action stops at this height for a period of time (during this period, the hydraulic oil in the oil circuit from the balance valve 8 to the hoisting motor 1 is due to leakage. When the lifting operation is performed again, the opening pressure of the brake 2 is relatively low, so that when the working pressure of the first working oil port A has not reached the pressure required for lifting the load, the brake 2 has been opened. In this way, the winch motor 1 does not perform the lifting action, but instead produces a lowering action under the load, resulting in the reverse and sliding phenomenon in the initial stage of the second lifting

This phenomenon not only affects the overall performance of the crane, but also easily causes unnecessary accidents.

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