Digital hydraulic hoisting mechanism and crane

Abstract

The digital hydraulic hoisting mechanism comprises a digital reversing valve and a hydraulic motor which are arranged on the two sides of a winding drum, a working oil port of the digital reversing valve is in pipeline connection with a working oil port of the hydraulic motor, a feedback rod of the digital reversing valve is in driving connection with the winding drum, and mechanical closed-loop feedback of the winding drum to the digital reversing valve is achieved. The control precision and the response speed of the hoisting mechanism are improved through the digital hydraulic control technology, meanwhile, mechanical closed-loop feedback is conducted on the digital reversing valve through the winding drum with the low rotating speed, the service life of the digital reversing valve is prolonged, and the problems that in the prior art, the control precision is low, the response speed is low, and the reliability service life is short are solved.

Description

Technical Field

[0001] This invention relates to the field of digital hydraulic control technology, and in particular to a digital hydraulic winch mechanism and crane. Background Technology

[0002] The hoisting mechanism of a crane mainly includes components such as a drum, a reducer, a hydraulic motor, and a balance valve. The drum is fixed on the crane frame, and the hydraulic motor drives the drum to rotate through the reducer. The steel wire rope wound on the drum is used to lift or pull the heavy object to achieve the lifting and lowering of the heavy object. When a crane lifts heavy objects, a proportional valve is generally used to control the motor rotation. The pilot pressure controls the direction of movement and opening of the proportional valve core, thereby controlling the motor's direction and speed, achieving the lifting and lowering and speed control of the hoisting mechanism. The motor speed range can reach 50 to 5000 r / min. However, this control system is an open-loop control, which cannot precisely control the drum's speed and angle. At the same time, due to the internal leakage of the hydraulic system under heavy load conditions, the motor is prone to problems such as delay and vibration when operating the crane hoisting mechanism at low speed under heavy load. Furthermore, asynchrony occurs when operating dual hoists for synchronous lifting operations. Therefore, when precise control of the lifting and lowering speed of heavy objects is required, or when performing micro-movement lifting and lowering operations, the existing open-loop control method of the crane hoisting mechanism is affected by the internal leakage of the heavy load system, resulting in low hoisting speed control accuracy and delayed response under heavy load, which often fails to meet the requirements.

[0003] The rotating mechanism controlled by digital hydraulics uses a hydraulic motor shaft to achieve mechanical closed-loop feedback to the digital valve. For example, Chinese patent CN208749725U discloses a digital hydraulic control system for a rotating mechanism. In this system, because the hydraulic motor operates at a high speed, the digital valve also operates at the same high speed, resulting in low reliability and lifespan. If a speed reducer is added between the motor and the digital valve, the cost will be high. At the same time, the system does not have a balance valve on the motor oil port, so it cannot achieve the heavy load condition of the hoisting system lifting heavy objects. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a digital hydraulic winch mechanism and crane, which solves the problems of low winch control accuracy, slow response speed and low reliability and lifespan in the existing technology.

[0005] Technical solution: To achieve the above objectives, the present invention provides a digital hydraulic winch mechanism, comprising a digital directional valve and a hydraulic motor arranged on both sides of the drum. The working oil port of the digital directional valve is connected to the working oil port of the hydraulic motor via a pipeline. The feedback rod of the digital directional valve is connected to the drum drive, thereby realizing a mechanical closed-loop feedback between the drum and the digital directional valve.

[0006] Preferably, the digital directional valve includes a motor, an end cover, a valve body, a valve core, a feedback rod, and a coupling. The motor is driven to the valve core via the coupling. One end of the feedback rod is threaded to the valve core, and the other end is driven to the drum. The motor drives the valve core to move left / right to open the valve core opening of the digital directional valve. High-pressure oil enters the upper / lower drive chamber of the hydraulic motor through the working port of the digital directional valve. The hydraulic motor drives the drum to rotate in different directions using a reducer. At the same time, the drum drives the feedback rod on the digital directional valve to rotate, causing the valve core on the digital directional valve to move right / left to close the valve core opening, thereby realizing the mechanical closed-loop control of the hoisting mechanism.

[0007] Preferably, it also includes a control element, wherein the control signal output by the control element controls the digital directional valve to switch, and the hydraulic motor is driven to rotate by a high-pressure oil source.

[0008] Preferably, the speed and angle of the hydraulic motor are controlled by controlling the pulse frequency and the number of pulses output by the control element.

[0009] Preferably, it also includes a balance valve connected in series in the pipeline connecting the working port of the digital directional valve and the working port of the hydraulic motor.

[0010] Preferably, when the balance valve is hoisted, the high-pressure oil source output by the digital directional valve automatically opens the one-way valve core of the balance valve and enters the working oil port of the hydraulic motor.

[0011] Preferably, when the winch is lowering, the high-pressure oil source output by the digital directional valve opens the throttle valve core of the balance valve through the pilot oil port K of the balance valve to generate back pressure and prevent the heavy object from falling at a loss.

[0012] Preferably, when the hoisting mechanism is stationary, the control element does not output a control signal, there is no pressure oil source in the oil circuit between the working port of the digital directional valve and the hydraulic motor and the balance valve, and the balance valve is in the valve core closed state.

[0013] The crane described in this invention includes the digital hydraulic winch mechanism described above.

[0014] Beneficial effects: The present invention has the following advantages: The present invention utilizes digital hydraulic technology to perform mechanical closed-loop control of the hoisting mechanism, thereby improving the control accuracy and response speed of the hoisting mechanism, and provides mechanical feedback to the digital directional valve directly through the low-speed drum, thereby extending the service life of the digital directional valve and reducing costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a digital hydraulic winch mechanism.

[0016] In the diagram, 1: Control element; 2: Digital directional valve; 21: Motor; 22: End cover; 23: Valve body; 24: Valve core; 25: Feedback rod; 26: Coupling; 3: Drum; 4: Reducer; 5: Hydraulic motor; 6: Balance valve; P: High-pressure oil port; T: Return oil port; A1: First working oil port of digital directional valve; B1: Second working oil port of digital directional valve; A2: First working oil port of hydraulic motor; B2: Second working oil port of hydraulic motor; A3: First working oil port of balance valve; B3: Second working oil port of balance valve; K: Pilot port of balance valve. Detailed Implementation

[0017] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0018] like Figure 1 As shown, the digital hydraulic winch mechanism and crane of the present invention include a control element 1, a digital directional valve 2, a drum 3, a reducer 4, a hydraulic motor 5, and a balance valve 6. The reducer 4 is installed inside the drum 3, and one side of the reducer 4 is fixedly connected to the crane frame, allowing the drum 3 to rotate freely on the frame. The hydraulic motor 5 is driven by the reducer 4, ultimately driving the drum 3 to rotate. The balance valve 6 is fixed to the working port of the hydraulic motor 5 and is used for controlling the forward and reverse oil circuits of the hydraulic motor 5. The working port of the digital directional valve 2 is connected to the working port pipelines of the hydraulic motor 5 and the balance valve 6. The feedback rod 25 of the digital directional valve 2 is driven by the drum 3, realizing a mechanical closed-loop feedback from the drum 3 to the digital directional valve 2.

[0019] The control signal output by control element 1 controls the digital directional valve 2 to switch, and uses a high-pressure oil source to drive the hydraulic motor 5 to rotate. Based on the pulse frequency and number of pulses of control element 1, the speed and angle of the hydraulic motor 5 are controlled. The hydraulic motor 5 drives the drum 3 to rotate through the reducer 4 to realize the lifting and lowering of the heavy object. At the same time, the digital directional valve 2 uses the rotation of the drum 3 to form a mechanical closed-loop feedback, causing the digital directional valve 2 to close, ensuring that the speed and angle of the hoisting mechanism correspond one-to-one with the pulse frequency and number of pulses of control element 1, thereby improving the control accuracy and response speed of the hoisting mechanism.

[0020] The digital directional valve 2 includes a motor 21, a coupling 26, an end cover 22, a valve body 23, a valve core 24, and a feedback rod 25. The motor 21 is driven to the valve core 24 via the coupling 26. One end of the feedback rod 25 is threaded to the valve core 24, and the other end is driven to the drum 3. The motor 21 drives the valve core 24 to move left / right as shown in the figure to open the valve core opening of the digital directional valve 2. The high-pressure oil source enters the upper / lower drive chamber of the hydraulic motor 5 through the working oil port of the digital directional valve 2. The hydraulic motor 5 drives the drum 3 to rotate in different directions using the reducer 4. At the same time, the drum 3 drives the feedback rod 25 on the digital directional valve 2 to rotate, causing the valve core 24 on the digital directional valve 2 to move right / left as shown in the figure to close the valve core opening of the digital directional valve 2, thereby realizing the mechanical closed-loop control of the hoisting mechanism.

[0021] The winch operation includes hoisting, lowering, and stationary operation. The specific working principle is as follows:

[0022] Operating State 1: The hoisting mechanism pulls the heavy object to lift. Control element 1 outputs a control signal to control motor 21 to rotate counterclockwise, driving the valve core 24 of digital directional valve 2 to move to the left side of the diagram. The high-pressure oil source connects to the first working port A1 of digital directional valve 2 via the high-pressure oil port P on digital directional valve 2, supplying oil to the first working port A3 of balance valve 6. The high-pressure oil source automatically opens the one-way valve core of balance valve 6 and enters the first working port A2 of hydraulic motor 5 via the second working port B3 of balance valve 6. The oil in the second working port B2 of hydraulic motor 5 flows through the second working port A2 of digital directional valve 2. Oil port B1 is connected to oil return port T on digital directional valve 2 to return to the oil tank, driving hydraulic motor 5 to rotate counterclockwise. Hydraulic motor 5 drives drum 3 to rotate counterclockwise through reducer 4. The steel wire rope wound on drum 3 pulls the heavy object to lift. At the same time, drum 3 drives feedback rod 25 on digital directional valve 2 to rotate counterclockwise. Through the threaded connection between feedback rod 25 and valve core 24, valve core 24 is driven to move to the right of the figure to close the valve core opening, realizing mechanical closed-loop control of the hoisting mechanism, ensuring that the speed and angle of the hoisting mechanism correspond one-to-one with the pulse frequency and pulse number of control element 1.

[0023] Operating State 2: The hoisting mechanism pulls the heavy object down. Control element 1 outputs a control signal to control motor 21 to rotate clockwise, driving the valve core 24 of digital directional valve 2 to move to the right side of the diagram. The high-pressure oil source connects to the second working port B1 of digital directional valve 2 via the high-pressure oil port P on digital directional valve 2 to supply oil to the second working port B2 of hydraulic motor 5. At the same time, the high-pressure oil output from the second working port B1 of digital directional valve 2 opens the throttle valve core of balance valve 6 via the pilot oil port K of balance valve 6, so that the return oil generated by the first working port A2 of hydraulic motor 5 is connected to the first working port A3 of balance valve 6 via the second working port B3 of balance valve 6, and returns to the oil tank through the first working port A1 of digital directional valve 2 and the return oil port T on digital directional valve 2, driving hydraulic motor 5 to rotate clockwise. The throttle valve core of balance valve 6 can generate return oil back pressure to prevent the heavy object from falling slowly. The hydraulic motor 5 drives the drum 3 to rotate clockwise through the reducer 4, and pulls the heavy object down through the steel wire rope wound on the drum 3. At the same time, the drum 3 drives the feedback rod 25 on the digital directional valve 2 to rotate clockwise, which drives the valve core 24 of the digital directional valve 2 to move to the left of the figure to close the valve core opening, thereby realizing the mechanical closed-loop control of the hoisting mechanism.

[0024] Working state 3: The hoisting mechanism is stationary, the control element 1 does not output control signals, there is no pressure oil source in the oil circuit between the working port of the digital directional valve 2 and the hydraulic motor 5 and the balance valve 6, the balance valve 6 is in the valve core closed state, the balance valve 6 cuts off the oil circuit connection between the first working port A2 of the hydraulic motor 5 and the first working port A1 of the digital directional valve 2, which can prevent the heavy object from pulling the drum 3 to fall at a loss.

[0025] Note: The rotation direction is from left to right as shown in the diagram.

Claims

1. A digital hydraulic winch mechanism, characterized in that, It includes a digital directional valve (2) and a hydraulic motor (5) arranged on both sides of the drum (3). The working oil port of the digital directional valve (2) is connected to the working oil port of the hydraulic motor (5) through a pipeline. The feedback rod (25) of the digital directional valve (2) is connected to the drum (3) for driving, so that the drum (3) forms a mechanical closed-loop feedback to the digital directional valve (2).

2. The digital hydraulic winch mechanism according to claim 1, characterized in that, The digital directional valve (2) includes a motor (21), an end cap (22), a valve body (23), a valve core (24), a feedback rod (25), and a coupling (26). The motor (21) is driven to connect with the valve core (24) through the coupling (26). One end of the feedback rod (25) is threaded to the valve core (24), and the other end is driven to connect with the drum (3). The motor (21) drives the valve core (24) to move left / right to open the valve core opening of the digital directional valve (2). The high-pressure oil source enters the upper / lower drive chamber of the hydraulic motor (5) through the working oil port of the digital directional valve (2). The hydraulic motor (5) drives the drum (3) to rotate in different directions using the reducer 4. At the same time, the drum (3) drives the feedback rod (25) on the digital directional valve (2) to rotate, causing the valve core (24) on the digital directional valve (2) to move right / left to close the valve core opening of the digital directional valve (2), thereby realizing the mechanical closed-loop control of the hoisting mechanism.

3. The digital hydraulic winch mechanism according to claim 1, characterized in that, It also includes a control element (1), the control signal output by the control element (1) controls the digital directional valve (2) to switch, and uses a high-pressure oil source to drive the hydraulic motor (5) to rotate.

4. The digital hydraulic winch mechanism according to claim 3, characterized in that, The speed and angle of the hydraulic motor (5) are controlled by the pulse frequency and number of pulses output by the control element (1).

5. The digital hydraulic winch mechanism according to claim 3, characterized in that, It also includes a balance valve (6) connected in series on the pipeline connecting the working port of the digital directional valve (2) and the working port of the hydraulic motor (5).

6. The digital hydraulic winch mechanism according to claim 5, characterized in that, When the balance valve (6) is hoisted, the high-pressure oil source output by the digital directional valve (2) automatically opens the one-way valve core of the balance valve (6) and enters the working oil port of the hydraulic motor (5).

7. The digital hydraulic winch mechanism according to claim 5, characterized in that, When the winch is lowered, the high-pressure oil source output by the digital directional valve (2) opens the throttle valve core of the balance valve (6) through the pilot oil port K of the balance valve (6) to generate back pressure and prevent the heavy object from falling at a loss.

8. The digital hydraulic winch mechanism according to claim 5, characterized in that, When the hoisting mechanism is stationary, the control element (1) does not output a control signal, and there is no pressure oil source in the oil circuit between the working port of the digital directional valve (2) and the hydraulic motor (5) and the balance valve (6). The balance valve (6) is in the valve core closed state.

9. A crane, characterized in that, Includes the digital hydraulic winch mechanism as described in any one of claims 1-8.

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