Digital hydraulic system of crane

Abstract

The invention discloses a digital hydraulic system of a crane, which comprises a digital hydraulic controller, a digital oil pump, a digital rotary motor, a digital winch motor, a variable-amplitude digital oil cylinder, a telescopic digital oil cylinder and a plurality of pressure sensors, each of the digital oil pump, the digital rotary motor, the digital winch motor, the variable amplitude digital oil cylinder and the telescopic digital oil cylinder comprises a hydraulic mechanism, a digital valve arranged at an oil inlet of the hydraulic mechanism and a stepping motor used for driving a valve core in the digital valve to move; an oil inlet and an oil outlet of the hydraulic mechanism are connected to a main oil inlet pipeline and a main oil outlet pipeline of the hydraulic system respectively, pressure sensors are arranged at the oil inlet and the oil outlet of the hydraulic mechanism, and all the stepping motors and the pressure sensors are correspondingly connected with a digital hydraulic controller respectively. According to the invention, the digital hydraulic controller is adopted to carry out digital control on each execution element of the crane, the control precision is high, the vibration impact in the movement process is small, and the micro-motion performance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of crane hydraulic systems, in particular to a crane digital hydraulic system. Background Art

[0002] Traditional crane topside hydraulic systems usually adopt an open-loop control method of gear pump / load-sensing variable pump + hydraulic / electrically controlled main valve + actuator. During use, the crane topside hydraulic system is affected by the throttling effect of the valve, the temperature of the hydraulic oil, the change of elastic modulus and the performance of the actuator. This open-loop control method cannot accurately control the motion accuracy of the actuator, resulting in jitter, impact and poor micro-motion of the hydraulic system. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a digital hydraulic system for a crane, which adopts a digital hydraulic controller to digitally control each actuator of the crane, with high control accuracy, small vibration and impact during movement, and good micro-movement.

[0004] The technical solution of the present invention is:

[0005] A digital hydraulic system for a crane includes a digital hydraulic controller, a digital oil pump, a digital slewing motor, a digital hoisting motor, a digital luffing cylinder, a digital telescopic cylinder, and a plurality of pressure sensors;

[0006] The digital oil pump includes a hydraulic oil pump, a digital valve provided at the oil inlet of the hydraulic oil pump, and a stepper motor for driving the movement of the valve core in the digital valve. The digital rotary motor and the digital winch motor each include a hydraulic motor, a digital valve provided at the oil inlet of the hydraulic motor, and a stepper motor for driving the movement of the valve core in the digital valve. The variable amplitude digital oil cylinder and the telescopic digital oil cylinder each include a hydraulic oil cylinder, a digital valve provided at the oil inlet of the hydraulic oil cylinder, and a stepper motor for driving the movement of the valve core in the digital valve.

[0007] The control ends of the stepping motors of the digital oil pump, digital slewing motor, digital hoisting motor, luffing digital oil cylinder and telescopic digital oil cylinder are respectively connected to the digital hydraulic controller. The hydraulic oil pump of the digital oil pump is arranged on the inlet end of the main oil inlet pipeline of the hydraulic system. The oil inlets of the hydraulic motors of the digital slewing motor and digital hoisting motor, as well as the hydraulic cylinders of the luffing digital oil cylinder and telescopic digital oil cylinder are all connected to the main oil inlet pipeline of the hydraulic system, and their oil outlets are all connected to the main oil outlet pipeline of the hydraulic system.

[0008] The multiple pressure sensors are load pressure sensors respectively arranged at the oil inlet and oil outlet of the hydraulic motor of the digital slewing motor and the digital winch motor, and at the oil inlet and oil outlet of the hydraulic cylinder of the amplitude-changing digital cylinder and the telescopic digital cylinder. The multiple load pressure sensors are all connected to the digital hydraulic controller.

[0009] A system pump outlet pressure sensor is provided at the outlet of the digital oil pump, and the system pump outlet pressure sensor is connected to the digital hydraulic controller.

[0010] The digital hydraulic controller is connected to a CAN bus, the control end of the stepper motor of the digital oil pump is connected to the output end of the oil pump driver, the control end of the stepper motor of the digital rotary motor is connected to the output end of the rotary driver, the control end of the stepper motor of the digital winch motor is connected to the output end of the winch driver, the control end of the stepper motor of the variable amplitude digital oil cylinder is connected to the output end of the variable amplitude driver, and the control end of the stepper motor of the telescopic digital oil cylinder is connected to the output end of the telescopic driver. The CAN input ends of the oil pump driver, rotary driver, winch driver, variable amplitude driver, and telescopic driver are respectively connected to the CAN bus.

[0011] The digital winch motor includes a digital main winch motor and a digital auxiliary winch motor. The digital main winch motor and the digital auxiliary winch motor both include a hydraulic motor, a digital valve arranged at the oil inlet of the hydraulic motor, and a stepper motor for driving the movement of the valve core in the digital valve. The control ends of the stepper motors of the main winch motor and the digital auxiliary winch motor are respectively connected to the digital hydraulic controller.

[0012] The digital hydraulic controller is connected to an electric control emergency stop bus, and the emergency stop input terminals of the oil pump driver, rotary driver, winch driver, luffing driver and telescopic driver are respectively connected to the electric control emergency stop bus.

[0013] A manual emergency stop bus is connected in parallel to the electric emergency stop bus, and a manual emergency stop switch is provided on the manual emergency stop bus.

[0014] Advantages of the present invention:

[0015] (1) The present invention eliminates the hydraulic / electrically controlled main valve of the crane and adopts a digital hydraulic controller to digitally control each actuator of the crane, which greatly reduces the number of hydraulic components and hydraulic pipelines, reduces the volume and weight, and makes maintenance more convenient.

[0016] (2) The present invention adopts digital control to replace the hydraulic pipeline control of the hydraulic / electrically controlled main valve, which is insensitive to the influence of the external environment (temperature, oil pollution, etc.) and has more precise control.

[0017] (3) The actuators of the present invention (slewing mechanism, hoisting mechanism, luffing mechanism and telescopic boom mechanism) are controlled by a digital hydraulic controller, which has high control accuracy, small vibration and impact during the movement process, and good micro-motion performance.

[0018] (4) The present invention sets pressure sensors at the oil inlet and outlet of each actuator, calculates the required flow of the actuator through the pressure difference between the inlet and outlet, realizes real-time matching of the flow of the hydraulic system, improves the response performance of the hydraulic system, avoids the system stability and response lag problems caused by the pressure transmission hysteresis brought by the long pipeline in the traditional hydraulic system, and eliminates the multi-way valve in the system, thereby reducing the energy consumption of the system.

[0019] (5) The present invention provides a system pump outlet pressure sensor at the outlet of the digital oil pump. Since the hydraulic pipeline is long and there is pressure loss, the oil pressure at the oil inlet of the actuator is calibrated by the oil pressure at the pump outlet to improve the accuracy of feedback control. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a hydraulic piping diagram of the present invention.

[0021] Figure 2 It is a control link diagram of the present invention.

[0022] Figure markings: 1-digital hydraulic controller, 2-digital oil pump, 3-digital rotary motor, 4-digital main winch motor, 5-digital auxiliary winch motor, 6-boom digital cylinder, 7-telescopic digital cylinder, 8-main oil inlet pipeline, 9-main oil outlet pipeline, 10-CAN bus, 11-oil pump driver, 12-rotation driver, 13-main winch driver, 14-auxiliary winch driver, 15-boom driver, 16-telescopic driver, 17-system pump outlet pressure sensor, 18-load pressure sensor, 19-electrically controlled emergency stop bus, 20-manual emergency stop bus, 21-manual emergency stop switch. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] See Figure 1 and Figure 2 A digital hydraulic system for a crane includes a digital hydraulic controller 1, a digital oil pump 2, a digital slewing motor 3, a digital main hoisting motor 4, a digital auxiliary hoisting motor 5, a digital luffing cylinder 6, a digital telescopic cylinder 7, and a plurality of pressure sensors;

[0025] The digital oil pump 2 includes a hydraulic oil pump, a digital valve provided at the oil inlet of the hydraulic oil pump, and a stepper motor for driving the movement of the valve core in the digital valve. The digital rotary motor 3, the digital main hoisting motor 4, and the digital auxiliary hoisting motor 5 each include a hydraulic motor, a digital valve provided at the oil inlet of the hydraulic motor, and a stepper motor for driving the movement of the valve core in the digital valve. The variable amplitude digital oil cylinder 6 and the telescopic digital oil cylinder 7 each include a hydraulic oil cylinder, a digital valve provided at the oil inlet of the hydraulic oil cylinder, and a stepper motor for driving the movement of the valve core in the digital valve.

[0026] The digital valves of the digital oil pump 2, digital slewing motor 3, digital main hoisting motor 4, digital auxiliary hoisting motor 5, luffing digital oil cylinder 6, and telescopic digital oil cylinder 7 are respectively arranged on the outside of each hydraulic actuator (hydraulic oil pump, hydraulic motor or hydraulic oil cylinder). The oil inlet of the digital valve is connected to the main oil inlet pipeline through a pipeline, and the oil outlet of the digital valve is connected to the oil inlet of the corresponding hydraulic actuator through a pipeline.

[0027] The hydraulic oil pump of the digital oil pump 2 is arranged on the inlet end of the main oil inlet pipeline 8 of the hydraulic system to realize the oil supply control of the main oil inlet pipeline 8. The hydraulic motors of the digital slewing motor 3, the digital main hoisting motor 4 and the digital auxiliary hoisting motor 5, as well as the oil outlets of the hydraulic cylinders of the digital luffing cylinder 6 and the telescopic digital cylinder 7 are all connected to the main oil outlet pipeline 9 of the hydraulic system.

[0028] The digital hydraulic controller 1 is connected to a CAN bus 10. The control end of the stepper motor of the digital oil pump 2 is connected to the output end of the oil pump driver 11. The control end of the stepper motor of the digital rotary motor 3 is connected to the output end of the rotary driver 12. The control end of the stepper motor of the digital main hoist motor 4 is connected to the output end of the main hoist driver 13. The control end of the stepper motor of the digital auxiliary hoist motor 5 is connected to the output end of the auxiliary hoist driver 14. The control end of the stepper motor of the variable amplitude digital oil cylinder 6 is connected to the output end of the variable amplitude driver 15. The control end of the stepper motor of the telescopic digital oil cylinder 7 is connected to the output end of the telescopic driver 16. The oil pump driver 11 , the CAN input ends of the slewing drive 12, the main hoisting drive 13, the auxiliary hoisting drive 14, the luffing drive 15, and the telescopic drive 16 are respectively connected to the CAN bus 10; the digital hydraulic controller 1 sends a pulse signal to the driver of each actuator (the oil pump driver 11, the slewing drive 12, the main hoisting drive 13, the auxiliary hoisting drive 14, the luffing drive 15, and the telescopic drive 16), and the driver of each actuator controls the corresponding stepper motor to rotate, and the stepper motor drives the valve core in the digital valve to move, thereby adjusting the opening of the digital valve. The oil on the main oil inlet pipeline 8 enters the corresponding hydraulic motor or hydraulic cylinder through the digital valve;

[0029] The multiple pressure sensors are respectively a system pump outlet pressure sensor 17 arranged at the outlet of the digital oil pump 2, a load pressure sensor 18 arranged at the oil inlet and oil outlet of the hydraulic motors of the digital slewing motor 3, the digital main hoisting motor 4 and the digital auxiliary hoisting motor 5, and the oil inlet and oil outlet of the hydraulic cylinders of the variable amplitude digital oil cylinder 6 and the telescopic digital oil cylinder 7. The system pump outlet pressure sensor 17 and the multiple load pressure sensors 18 are all connected to the digital hydraulic controller 1; the digital hydraulic controller 1 calculates the required flow rate of the actuator through the pressure difference between the inlet and outlet of the hydraulic motor or hydraulic cylinder to achieve precise control, and because the main oil inlet pipeline 8 is long and there is pressure loss, the oil pressure of the pump outlet is collected by the system pump outlet pressure sensor 17 to calibrate the oil pressure of the actuator oil inlet, thereby improving the accuracy of feedback control;

[0030] The digital hydraulic controller 1 is connected to an electric control emergency stop bus 19, and the emergency stop input ends of the oil pump driver 11, the rotary driver 12, the main winch driver 13, the auxiliary winch driver 14, the variable amplitude driver 15, and the telescopic driver 16 are respectively connected to the electric control emergency stop bus 19. A manual emergency stop bus 20 is connected in parallel to the electric control emergency stop bus 19, and a manual emergency stop switch 21 is provided on the manual emergency stop bus 20. The emergency stop operation of the stepper motor of each actuator can be realized through the digital hydraulic controller 1 and the manual emergency stop switch 21.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A digital hydraulic system for a crane, characterized by: It includes a digital hydraulic controller, a digital oil pump, a digital slewing motor, a digital winch motor, a digital hydraulic cylinder for variable amplitude and a digital hydraulic cylinder for telescopic operation, and multiple pressure sensors; The digital oil pump includes a hydraulic oil pump, a digital valve provided at the oil inlet of the hydraulic oil pump, and a stepper motor for driving the movement of the valve core in the digital valve. The digital rotary motor and the digital winch motor each include a hydraulic motor, a digital valve provided at the oil inlet of the hydraulic motor, and a stepper motor for driving the movement of the valve core in the digital valve. The variable amplitude digital oil cylinder and the telescopic digital oil cylinder each include a hydraulic oil cylinder, a digital valve provided at the oil inlet of the hydraulic oil cylinder, and a stepper motor for driving the movement of the valve core in the digital valve. The control ends of the stepping motors of the digital oil pump, digital slewing motor, digital hoisting motor, luffing digital oil cylinder and telescopic digital oil cylinder are respectively connected to the digital hydraulic controller. The hydraulic oil pump of the digital oil pump is arranged on the inlet end of the main oil inlet pipeline of the hydraulic system. The oil inlets of the hydraulic motors of the digital slewing motor and digital hoisting motor, as well as the hydraulic cylinders of the luffing digital oil cylinder and telescopic digital oil cylinder are all connected to the main oil inlet pipeline of the hydraulic system, and their oil outlets are all connected to the main oil outlet pipeline of the hydraulic system. The multiple pressure sensors are load pressure sensors respectively arranged at the oil inlet and oil outlet of the hydraulic motor of the digital slewing motor and the digital winch motor, and at the oil inlet and oil outlet of the hydraulic cylinder of the amplitude-changing digital cylinder and the telescopic digital cylinder. The multiple load pressure sensors are all connected to the digital hydraulic controller.

2. A digital hydraulic system for a crane according to claim, characterized in that: A system pump outlet pressure sensor is provided at the outlet of the digital oil pump, and the system pump outlet pressure sensor is connected to the digital hydraulic controller.

3. A digital hydraulic system for a crane according to claim, characterized in that: The digital hydraulic controller is connected to a CAN bus, the control end of the stepper motor of the digital oil pump is connected to the output end of the oil pump driver, the control end of the stepper motor of the digital rotary motor is connected to the output end of the rotary driver, the control end of the stepper motor of the digital winch motor is connected to the output end of the winch driver, the control end of the stepper motor of the variable amplitude digital oil cylinder is connected to the output end of the variable amplitude driver, and the control end of the stepper motor of the telescopic digital oil cylinder is connected to the output end of the telescopic driver. The CAN input ends of the oil pump driver, rotary driver, winch driver, variable amplitude driver, and telescopic driver are respectively connected to the CAN bus.

4. A digital hydraulic system for a crane according to claim 1, characterized in that: The digital winch motor includes a digital main winch motor and a digital auxiliary winch motor. The digital main winch motor and the digital auxiliary winch motor both include a hydraulic motor, a digital valve arranged at the oil inlet of the hydraulic motor, and a stepper motor for driving the movement of the valve core in the digital valve. The control ends of the stepper motors of the main winch motor and the digital auxiliary winch motor are respectively connected to the digital hydraulic controller.

5. The digital hydraulic system for a crane according to claim 3, characterized in that: The digital hydraulic controller is connected to an electric control emergency stop bus, and the emergency stop input terminals of the oil pump driver, rotary driver, winch driver, luffing driver and telescopic driver are respectively connected to the electric control emergency stop bus.

6. A digital hydraulic system for a crane according to claim 5, characterized in that: A manual emergency stop bus is connected in parallel to the electric emergency stop bus, and a manual emergency stop switch is provided on the manual emergency stop bus.

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