Electro-hydraulic leveling system of aerial work platform

Abstract

The invention discloses an electro-hydraulic leveling system of an aerial work platform, which relates to the technical field of aerial work platforms and comprises a main oil inlet pipe, a main oil return pipe, a power input assembly, a first control valve group, a second control valve group, a third control valve group, an actuating mechanism, a detection module and a control module. According to the electro-hydraulic leveling system for the aerial work platform, a complex connecting rod mechanism, a chain or a steel wire rope necessary for mechanical leveling is abandoned, long-distance oil pipe layout for hydrostatic leveling is not needed, the occupied space is remarkably reduced, and the electro-hydraulic leveling system particularly meets the installation requirement of the aerial work platform with the height being 30 m or above. The constant pressure mode ensures quick response under the scenes of emergency leveling, quick amplitude variation of the boom and the like, and in the load sensitive mode, the shuttle valve gates the highest load pressure in real time and feeds back the highest load pressure to the variable pump, and meanwhile, the system power output is accurately matched with the action requirement in cooperation with the real-time transmission of the load pressure by each one-way valve.

Description

Technical Field

[0001] This application belongs to the field of aerial work platform technology, and particularly relates to an electro-hydraulic leveling system for aerial work platforms. Background Technology

[0002] In the field of aerial work, the leveling accuracy of the work platform has a direct impact on work safety and efficiency. Currently, the commonly used leveling methods for aerial work platforms and aerial work vehicles within 30 meters are mechanical leveling or hydrostatic leveling. Both of these leveling methods have significant drawbacks and are not suitable for equipment above 30 meters. At the same time, existing electro-hydraulic leveling solutions generally suffer from severe lag and large leveling errors.

[0003] Mechanical leveling involves installing a parallelogram linkage mechanism, chains, and wire ropes between the turntable and the work platform. Leveling is achieved by utilizing the principle that the opposite sides of the parallelogram remain parallel during operation. However, this method is bulky, requires a lot of space, and the error calibration and adjustment process is cumbersome, making it unsuitable for the space requirements of large-scale aerial work platforms.

[0004] The hydrostatic leveling method involves installing hydraulic cylinders between the turntable and the boom, and between the platform and the boom. The large chambers of these cylinders are connected to each other, and the small chambers are connected to each other, forming a closed system. The lower cylinder acts as the driving cylinder, and the upper cylinder as the driven cylinder. When the boom luffs, the driving cylinder extends or retracts, forcing hydraulic oil into the driven cylinder. Utilizing the identical cylinder and rod diameters of both cylinders, platform angle compensation is achieved. However, this leveling principle, based on approximately equal structures, inherently introduces leveling errors, which cannot be promptly compensated for by design and manufacturing errors in the structural components. Furthermore, the boom requires long-distance connecting oil pipes, leading to significant leveling lag and substantial cumulative errors over prolonged use. In addition, existing electro-hydraulic leveling solutions suffer from high system energy consumption, making it difficult to achieve efficient and energy-saving performance when combined with other functions of the overall machine system. Summary of the Invention

[0005] To address some or all of the technical problems existing in the prior art, this application provides an electro-hydraulic leveling system for aerial work platforms.

[0006] This application provides an electro-hydraulic leveling system for an aerial work platform, including a main oil inlet pipe, a main oil return pipe, a power input component, a first control valve group, a second control valve group, a third control valve group, an actuator, a detection module, and a control module. The power input component provides hydraulic power to the system, and its oil outlet is connected to the oil inlet of the first control valve group and the oil inlet of the second control valve group via pipelines, forming a pipeline layout in which the first control valve group and the power input component are connected in parallel, and the second control valve group and the third control valve group are connected in series. The actuator includes a telescopic cylinder for realizing the extension and retraction of the platform, a luffing cylinder for realizing the luffing of the platform, and a swing cylinder for realizing the oscillation of the platform. The system includes a swing cylinder and a leveling cylinder for achieving platform leveling. The telescopic cylinder and the luffing cylinder are connected to the working ports of the second control valve group, and the swing cylinder and the leveling cylinder are connected to the working ports of the third control valve group. The detection module includes an angle sensor for real-time acquisition of the platform's tilt state. The angle sensor is electrically connected to the control module and transmits tilt signals. The control module is electrically connected to the first, second, and third control valve groups, respectively. By receiving angle sensor signals and outputting control commands, it drives each control valve group to coordinate its actions, thereby controlling the actuator to complete telescopic, luffing, swinging, and leveling actions.

[0007] Preferably, the power input assembly includes a fuel tank, a variable displacement pump, and a filter; the fuel tank outlet is connected to the variable displacement pump inlet via a main inlet pipe, the variable displacement pump outlet is connected to the filter inlet via a pipeline, and the filter outlet is connected to two outlet pipelines.

[0008] Preferably, the first control valve group includes a sixth switching valve and a shuttle valve. The first oil outlet of the filter is connected to the first oil inlet of the sixth switching valve, the oil outlet of the sixth switching valve is connected to the first oil inlet of the shuttle valve, the oil outlet of the shuttle valve is connected to the pressure feedback port of the variable pump through a pipeline, and the second oil inlet of the sixth switching valve is connected to the main return oil pipe.

[0009] Preferably, the second valve group includes a first relief valve, a first speed control valve, a first switching valve, a first flow valve, and a first check valve; the inlet of the first speed control valve is connected to the second outlet pipeline of the filter, the outlet of the first speed control valve is connected to the inlet of the first switching valve, the two working ports of the first switching valve are respectively connected to the rodless chamber and the rod chamber of the telescopic cylinder through pipelines, and the outlet of the first switching valve is connected to the main return pipeline through a pipeline; the inlet of the first check valve is connected to the pipeline between the outlet of the first speed control valve and the inlet of the first switching valve, and the outlet of the first check valve is connected to the second inlet of the shuttle valve through a pipeline; the inlet of the first relief valve is connected to the second outlet pipeline of the filter, the first relief valve and the first speed control valve are arranged in parallel, and the outlet of the first relief valve is connected to the main return pipeline through a pipeline.

[0010] Preferably, the second valve group further includes a second speed regulating valve, a second switching valve, a second check valve, a first flow valve, a third switching valve, and a third check valve; the first speed regulating valve and the second speed regulating valve are arranged in parallel, the oil inlet of the second speed regulating valve is connected to the second oil outlet pipeline of the filter, the oil outlet of the second speed regulating valve is connected to the oil inlet of the second switching valve, the two working oil ports of the second switching valve are respectively connected to the rodless chamber and the rod chamber of the luffing cylinder through pipelines, and the oil outlet of the second switching valve is connected to the main return oil pipeline through a pipeline; the oil inlet of the second check valve... The pipeline connecting the outlet of the second speed control valve and the inlet of the second switching valve is connected to the outlet of the second check valve via a pipeline. The inlet of the first flow valve is connected to the second outlet pipeline of the filter. The outlet of the first flow valve is connected to the inlet of the third switching valve. The inlet of the third check valve is connected to the pipeline between the outlet of the first flow valve and the inlet of the third switching valve. The third check valve and the third switching valve are connected in parallel. The outlet of the third check valve is connected to the second inlet of the shuttle valve via a pipeline.

[0011] Preferably, the third control valve group includes a third speed regulating valve and a fourth switching valve; the oil inlet of the third speed regulating valve is connected to the oil outlet pipeline of the third switching valve, the oil outlet of the third speed regulating valve is connected to the oil inlet of the fourth switching valve, the two working oil ports of the fourth switching valve are respectively connected to the two chambers of the swing cylinder through pipelines, and the oil outlet of the fourth switching valve is connected to the main return oil pipe through pipelines.

[0012] Preferably, the third control valve group further includes a fourth speed regulating valve and a fifth switching valve. The oil inlet of the fourth speed regulating valve is connected to the oil outlet pipeline of the third switching valve. The third speed regulating valve and the fourth speed regulating valve are arranged in parallel. The oil outlet of the fourth speed regulating valve is connected to the oil inlet of the fifth switching valve. The two working oil ports of the fifth switching valve are respectively connected to the rodless chamber and the rod chamber of the leveling cylinder through pipelines. The oil outlet of the fifth switching valve is connected to the main return oil pipe through a pipeline.

[0013] Preferably, the third control valve group further includes a second relief valve, a second flow valve, a fourth check valve, and a fifth check valve; the inlet of the second relief valve is connected to the outlet pipeline of the third switching valve, the second relief valve is connected in parallel with the third speed control valve, and the outlet of the first relief valve is connected to the main return pipeline through a pipeline; the second flow valve is connected to the outlet pipeline of the third switching valve, the second flow valve is connected in parallel with the second relief valve, and the outlet of the second flow valve is connected back to the main return pipeline through a pipeline; the inlet of the fourth check valve is connected to the pipeline between the outlet of the third speed control valve and the inlet of the fourth switching valve, the inlet of the fifth check valve is connected to the pipeline between the outlet of the fourth speed control valve and the inlet of the fifth switching valve, and the outlets of both the fourth and fifth check valves are connected to the feedback end of the second flow valve through pipelines.

[0014] Preferably, the opening ends of both the main oil inlet pipe and the main oil return pipe are located inside the oil tank.

[0015] The electro-hydraulic leveling system for aerial work platforms proposed in this application has the following advantages and positive effects: (1) The constant pressure mode can be specifically adapted to scenarios with high response speed requirements, such as emergency leveling and rapid boom luffing. By maintaining a constant system pressure, it ensures that the actuator can start and run quickly in an instant, meeting the leveling and operation needs under sudden working conditions. In load-sensitive mode, the shuttle valve can capture and select the highest load pressure of each branch in real time. With the real-time transmission of load pressure by each check valve, the variable pump can accurately sense the system's action requirements, dynamically adjust the power output, and achieve on-demand matching of flow and pressure, avoiding energy waste. At the same time, this closed-loop control logic completely avoids the action lag problem caused by long oil pipe transmission in hydrostatic leveling, allowing the leveling action to respond to the tilt state of the platform in an instant, ensuring that the tilt deviation can be quickly corrected, and guaranteeing the stability and safety of the platform during operation.

[0016] (2) The unloading mode reduces the standby energy consumption of the equipment, which is significantly lower than the existing electro-hydraulic leveling scheme. The system limits the maximum flow of each branch through the first flow valve to avoid mutual interference between the extension, amplitude, swing and leveling actions, so as to achieve stable operation of multiple actions in coordination, perfectly adapt to the whole system, and achieve the dual goals of energy saving and high efficiency.

[0017] (3) The complex linkage mechanism, chain or wire rope required for mechanical leveling is eliminated, and the long-distance oil pipe layout of hydrostatic leveling is also eliminated, greatly reducing the space occupied, especially suitable for the installation requirements of aerial work platforms above 30 meters. The system has strong compatibility and can be adapted to aerial work equipment of different tonnage and types. It can also be applied to other electro-hydraulic leveling scenarios with work platform requirements, and has strong versatility. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only for further understanding of the embodiments of this application and constitute a part of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the hydraulic principle of the electro-hydraulic leveling system for the aerial work platform in this application; Figure 2 This is a schematic diagram of the hydraulic principle of the first control valve group in this application; Figure 3 This is a schematic diagram of the hydraulic principle of the second control valve group in this application; Figure 4 This is a schematic diagram of the hydraulic principle of the third control valve group in this application; Figure 5 This is a schematic diagram of the electro-hydraulic leveling system for the aerial work platform in this application.

[0019] Explanation of reference numerals in the attached figures: 1-Oil tank, 2-Variable pump, 3-Filter, 4-First control valve group, 5-Second control valve group, 6-Third control valve group, 71-First relief valve, 72-Second relief valve, 81-First speed control valve, 82-Second speed control valve, 83-Third speed control valve, 84-Fourth speed control valve, 91-First switching valve, 92-Second switching valve, 93-Third switching valve, 94-Fourth switching valve, 95-Fifth switching valve, 96-Sixth switching valve, 101-First flow valve, 102-Second flow valve, 111-First check valve, 112-Second check valve, 113-Third check valve, 114-Fourth check valve, 115-Fifth check valve, 12-Shuttle valve, 13-Telescopic cylinder, 14-Luffing cylinder, 15-Swing cylinder, 16-Leveling cylinder, 17-Angle sensor. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] like Figures 1 to 5As shown, the electro-hydraulic leveling system for aerial work platforms of this application includes a main oil inlet pipe, a main oil return pipe, a power input component, a first control valve group 4, a second control valve group 5, a third control valve group 6, an actuator, a detection module, and a control module. The power input component provides hydraulic power to the system, and its oil outlet is connected to the oil inlet of the first control valve group 4 and the oil inlet of the second control valve group 5 through pipelines, forming a pipeline layout in which the first control valve group 4 and the power input component are connected in parallel, and the second control valve group 5 and the third control valve group 6 are connected in series. The actuator includes a telescopic cylinder 13 for realizing the telescopic movement of the platform, a luffing cylinder 14 for realizing the luffing movement of the platform, and a swing cylinder 15 for realizing the swinging movement of the platform. The system includes a leveling cylinder 16 for achieving platform leveling, wherein the telescopic cylinder 13 and the luffing cylinder 14 are connected to the working ports of the second control valve group 5, and the swing cylinder 15 and the leveling cylinder 16 are connected to the working ports of the third control valve group 6. The detection module includes an angle sensor 17, which is used to collect the platform tilt status in real time. The angle sensor 17 is electrically connected to the control module and transmits tilt signals. The control module 18 is electrically connected to the first control valve group 4, the second control valve group 5, and the third control valve group 6, respectively. By receiving the signal from the angle sensor 17 and outputting control commands, it drives each control valve group to work together, thereby controlling the actuator to complete the telescopic, luffing, swinging, and leveling actions.

[0022] The telescopic cylinder 13 is fixed to the fixed section of the platform boom, and one end of the piston rod is fixed to the telescopic section of the boom, driving the boom to telescopically extend and retract, thus changing the horizontal working range of the work platform. When oil enters the rodless chamber, the piston rod extends and the boom lengthens; when oil enters the rod chamber, the piston rod retracts and the boom shortens.

[0023] The luffing cylinder 14 is fixed to the main frame of the platform, with one end of the piston rod hinged to the boom, allowing it to rotate with the boom during luffing. It drives the boom to perform luffing movements, changing the vertical working height of the work platform. When oil enters the rodless chamber, the piston rod extends, the boom rises, and the platform increases; when oil enters the rod chamber, the piston rod retracts, the boom lowers, and the platform decreases.

[0024] The oscillating cylinder 15 is fixed to the bottom frame of the platform, and the oscillating output shaft is fixedly connected to the platform's rotating mechanism. It can drive the platform to oscillate left and right, realizing the left and right oscillation adjustment of the work platform, allowing operators to flexibly adjust the working angle to adapt to different working position requirements. When oil enters the rodless chamber, the oscillating output shaft rotates clockwise, and the platform oscillates to the left; when oil enters the rod chamber, the oscillating output shaft rotates counterclockwise, and the platform oscillates to the right.

[0025] The leveling cylinder 16 is fixed to the rotating mechanism of the platform, with one end of the piston rod hinged to the platform's work railing. It can extend and retract to compensate for platform tilt, achieving horizontal adjustment of the work platform. When the angle sensor 17 detects platform tilt, the leveling cylinder 16 precisely extends and retracts under the command of the control module to compensate for the tilt angle, ensuring the work railing remains level at all times. When oil enters the rodless chamber, the piston rod extends, pushing one side of the work railing up; when oil enters the rod chamber, the piston rod retracts, lowering one side of the work railing.

[0026] Angle sensor 17 is a high-precision tilt sensor based on MEMS technology. It is bolted to the center of the work platform's work railing, maintaining a horizontal alignment with it. It detects the tilt angle of the work railing in real time, converting the tilt state into an electrical signal, which is continuously transmitted to the control module, providing precise signal input for leveling control. The control module has a built-in high-performance control chip and PID control algorithm program. It is equipped with signal input, signal output, and power interfaces, and is fixed inside the platform's control cabinet. It is electrically connected to the control coils of each switching valve and the electrical control interface of the speed control valve. It receives the tilt signal from angle sensor 17, compares it with the preset horizontal target value, and calculates the required amplitude and speed for leveling using the PID algorithm. It then controls the leveling cylinder 16 to precisely extend and retract until the platform returns to horizontal. Simultaneously, it can receive operator commands to control the overall extension, amplitude variation, and swinging movements of the machine.

[0027] like Figure 2 As shown, the power input assembly includes an oil tank 1, a variable displacement pump 2, and a filter 3. The oil outlet of the oil tank 1 is connected to the suction port of the variable displacement pump 2 via a main inlet pipe, and the oil outlet of the variable displacement pump 2 is connected to the inlet of the filter 3 via a pipeline. The oil outlet of the filter 3 is connected to two outlet pipelines. The openings of both the main inlet pipe and the main return pipe are located inside the oil tank 1. The variable displacement pump 2 converts the mechanical energy output by the motor into hydraulic energy, drawing oil from the oil tank 1 and outputting high-pressure oil. By receiving the load pressure signal fed back from the shuttle valve 12, the output flow and pressure are dynamically adjusted to achieve on-demand power supply, balancing power output and energy-saving requirements.

[0028] Filter 3 filters impurities, iron filings, and other contaminants from the output oil of variable pump 2, preventing particulate impurities from entering subsequent valve groups and actuators, preventing valve core jamming, seal wear, and other malfunctions, and ensuring the cleanliness and stability of the hydraulic system.

[0029] like Figure 2 As shown, the first control valve group 4 includes a sixth switching valve 96 and a shuttle valve 12. The first oil outlet of the filter 3 is connected to the first oil inlet of the sixth switching valve 96. The oil outlet of the sixth switching valve 96 is connected to the first oil inlet of the shuttle valve 12. The oil outlet of the shuttle valve 12 is connected to the pressure feedback port of the variable pump 2 through a pipeline. The second oil inlet of the sixth switching valve 96 is connected to the main return oil pipe.

[0030] like Figure 3 As shown, the second control valve group 5 includes a first relief valve 71, a first speed regulating valve 81, a first switching valve 91, a first flow valve 101, and a first check valve 111. The oil inlet of the first speed regulating valve 81 is connected to the second oil outlet of the filter 3, and the oil outlet of the first speed regulating valve 81 is connected to the oil inlet of the first switching valve 91. The two working oil ports of the first switching valve 91 are respectively connected to the rodless chamber and the rod chamber of the telescopic cylinder 13 through pipelines. The oil outlet of the first switching valve 91... The inlet of the first check valve 111 is connected to the main return oil pipe via a pipeline; the inlet of the first check valve 111 is connected to the pipeline between the outlet of the first speed control valve 81 and the inlet of the first switch valve 91, and the outlet of the first check valve 111 is connected to the second inlet of the shuttle valve 12 via a pipeline; the inlet of the first relief valve 71 is connected to the second outlet pipeline of the filter 3, the first relief valve 71 is set in parallel with the first speed control valve 81, and the outlet of the first relief valve 71 is connected to the main return oil pipe via a pipeline.

[0031] The shuttle valve 12 has a movable steel ball valve core inside, which achieves unidirectional conduction by relying on pressure difference. The first relief valve 71 sets the maximum working pressure of the whole hydraulic system. When the system pressure exceeds the set value, the main valve core moves, opening the oil inlet and outlet, and overflowing the excess high-pressure oil back to the oil tank 1 to achieve overload protection and prevent pipelines and valve groups from being damaged by high pressure.

[0032] The second control valve group 5 also includes a second speed regulating valve 82, a second switching valve 92, a second check valve 112, a first flow valve 101, a third switching valve 93, and a third check valve 113; the first speed regulating valve 81 and the second speed regulating valve 82 are connected in parallel. The oil inlet of the second speed regulating valve 82 is connected to the second oil outlet pipeline of the filter 3, and the oil outlet of the second speed regulating valve 82 is connected to the oil inlet of the second switching valve 92. The two working oil ports of the second switching valve 92 are respectively connected to the rodless chamber and the rod chamber of the luffing cylinder 14 through pipelines, and the oil outlet of the second switching valve 92 is connected to the main return oil pipeline through a pipeline; the oil inlet of the second check valve 112 is connected to... On the pipeline between the oil outlet of the second speed regulating valve 82 and the oil inlet of the second switching valve 92, the oil outlet of the second check valve 112 is connected to the second oil inlet of the shuttle valve 12 through a pipeline; the oil inlet of the first flow valve 101 is connected to the second oil outlet pipeline of the filter 3, the oil outlet of the first flow valve 101 is connected to the oil inlet of the third switching valve 93, the oil inlet of the third check valve 113 is connected on the pipeline between the oil outlet of the first flow valve 101 and the oil inlet of the third switching valve 93, the third check valve 113 and the third switching valve 93 are arranged in parallel, and the oil outlet of the third check valve 113 is connected to the second oil inlet of the shuttle valve 12 through a pipeline.

[0033] The first speed control valve 81 is used to adjust the extension and retraction speed of the telescopic cylinder 13, and the second speed control valve 82 is used to adjust the luffing speed of the luffing cylinder 14. The first flow valve 101 can limit the maximum flow rate entering the third control valve group 6, so as to avoid mutual interference between the platform movement and the extension and luffing movements of the whole machine, ensure the reasonable flow distribution of each action circuit, and ensure the stability of the system during multi-action coordinated operation.

[0034] The first check valve 111, the second check valve 112, and the third check valve 113 can collect the load pressure signal of each action circuit in real time and transmit the pressure signal unidirectionally to the shuttle valve 12 to provide load feedback data for the variable pump 2, ensuring that the variable pump 2 adjusts the output according to the maximum load demand of each branch and realizes load-sensitive control.

[0035] The third switching valve 93 can control the oil circuit connection between the second control valve group 5 and the third control valve group 6. It can also independently shut down the platform action oil circuit, realizing independent control of the whole machine action and the platform action, which is convenient for maintenance and troubleshooting.

[0036] like Figure 4 As shown, the third control valve group 6 includes a third speed regulating valve 83 and a fourth switching valve 94; the oil inlet of the third speed regulating valve 83 is connected to the oil outlet pipeline of the third switching valve 93, the oil outlet of the third speed regulating valve 83 is connected to the oil inlet of the fourth switching valve 94, the two working oil ports of the fourth switching valve 94 are respectively connected to the two chambers of the swing cylinder 15 through pipelines, and the oil outlet of the fourth switching valve 94 is connected to the main return oil pipe through a pipeline.

[0037] The third control valve group 6 also includes a fourth speed regulating valve 84 and a fifth switching valve 95. The oil inlet of the fourth speed regulating valve 84 is connected to the oil outlet pipeline of the third switching valve 93. The third speed regulating valve 83 and the fourth speed regulating valve 84 are arranged in parallel. The oil outlet of the fourth speed regulating valve 84 is connected to the oil inlet of the fifth switching valve 95. The two working oil ports of the fifth switching valve 95 are respectively connected to the rodless chamber and the rod chamber of the leveling cylinder 16 through pipelines. The oil outlet of the fifth switching valve 95 is connected to the main return oil pipe through a pipeline.

[0038] The third control valve group 6 also includes a second relief valve 72, a second flow valve 102, a fourth check valve 114, and a fifth check valve 115; the inlet of the second relief valve 72 is connected to the outlet pipeline of the third switching valve 93, and the second relief valve 72 is connected in parallel with the third speed control valve 83; the outlet of the first relief valve 71 is connected to the main return oil pipeline through a pipeline; the second flow valve 102 is connected to the outlet pipeline of the third switching valve 93, and the second flow valve 102 is connected in parallel with the second relief valve 72. 2. In parallel configuration, the oil outlet of the second flow valve 102 is connected back to the main return oil pipe through a pipeline; the oil inlet of the fourth check valve 114 is connected to the pipeline between the oil outlet of the third speed control valve 83 and the oil inlet of the fourth switch valve 94; the oil inlet of the fifth check valve 115 is connected to the pipeline between the oil outlet of the fourth speed control valve 84 and the oil inlet of the fifth switch valve 95; the oil outlets of both the fourth check valve 114 and the fifth check valve 115 are connected to the feedback end of the second flow valve 102 through pipelines.

[0039] The second overflow valve 72 can independently protect the platform's operating circuit, forming a two-stage safety protection with the first overflow valve 71, thus improving system safety. The third speed control valve 83 is used to adjust the swing speed of the swing cylinder 15, controlling the stability of the platform's left and right swing. The fourth speed control valve 84 is used to adjust the extension and retraction speed of the leveling cylinder 16, which can be adjusted electronically. During electronic adjustment, the flow rate is changed in real time according to the feedback signal from the angle sensor 17 to adapt to the leveling compensation requirements. The fourth switching valve 94 controls the swing direction of the swing cylinder 15, switching the valve core position by switching the coil on and off, thus realizing the bidirectional swing of the swing cylinder 15.

[0040] The fourth check valve 114 and the fifth check valve 115 can collect the load pressure signals of the swing cylinder 15 and the leveling cylinder 16 in real time, and transmit the pressure signals to the feedback end of the second flow valve 102, so that the second flow valve 102 can dynamically adjust the output flow according to the load change, ensuring the stability of the swing and leveling action.

[0041] This aerial work platform's electro-hydraulic leveling system achieves three operating modes through the coordinated action of the sixth switching valve 96, shuttle valve 12, and variable pump 2: When rapid response is required, the control module energizes the sixth switching valve 96, causing the valve core to move towards the coil, connecting the first oil inlet and outlet. Oil is fed back to the variable pump 2 via the first outlet pipeline of filter 3, the sixth switching valve 96, and shuttle valve 12, maintaining a constant pressure. Simultaneously, the second outlet pipeline supplies oil to the second control valve group 5 to drive the actuator, forming a constant pressure mode. When energy efficiency is required, the sixth switching valve 96... When valve 96 is also energized, the load pressure generated by the actuator is collected by each check valve and sent to the second oil inlet of shuttle valve 12. Shuttle valve 12 selects the highest load pressure and feeds it back to variable pump 2. Variable pump 2 adjusts the flow as needed to form a load-sensitive mode. When the equipment is in standby mode, the sixth switch valve 96 is de-energized. The valve core is reset and connected to the second oil inlet and outlet under the action of the reset spring. The high-pressure oil flows directly back to the oil tank 1 through the main return oil pipe and enters the unloading mode. The three modes are adapted to different operating scenarios to ensure system response speed, energy saving effect and standby safety.

[0042] The specific workflow is as follows: After the system starts, the variable pump 2 operates to draw oil from the oil tank 1, and after being pressurized, it outputs high-pressure oil. After the high-pressure oil is filtered for impurities by the filter 3, it is output in two ways: one way enters the sixth switch valve 96 of the first control valve group 4 through the first oil outlet pipeline, and the other way enters the second control valve group 5 through the second oil outlet pipeline.

[0043] The control module initializes, and angle sensor 17 begins to collect platform tilt signals in real time and transmit them to the control module. The control module presets the horizontal target value and the system working pressure threshold. The operator selects the working mode according to the operation requirements: when a rapid response is required, the control module sends an energizing command to the sixth switch valve 96, the valve core moves, connecting the first oil inlet and outlet, and the system switches to constant pressure mode, with variable pump 2 maintaining a constant pressure; when energy saving and high efficiency are required, the sixth switch valve 96 is also energized, the system switches to load-sensitive mode, shuttle valve 12 begins to select the highest load pressure in each branch and feeds it back to variable pump 2; when the equipment is in standby mode, the sixth switch valve 96 is de-energized, the valve core resets, the system enters unloading mode, and the high-pressure oil flows directly back to the oil tank 1.

[0044] The operator sends a telescopic signal to the control module via control commands. The control module then sends an energizing command to the first switching valve 91, causing the valve core to switch direction. Simultaneously, the operator adjusts the first speed regulating valve 81 to set the telescopic speed as needed. The high-pressure oil output from the filter 3, after its flow rate is regulated by the first speed regulating valve 81, enters the rodless or rod chamber of the telescopic cylinder 13 through the corresponding working port of the first switching valve 91, driving the piston rod to extend or retract, thus extending or retracting the boom. The oil in the other chamber of the telescopic cylinder 13 flows back to the main return oil pipe through the outlet of the first switching valve 91, ultimately returning to the oil tank 1. The first one-way valve 111 collects the load pressure signal of the telescopic cylinder 13 in real time and transmits it to the shuttle valve 12. The shuttle valve 12 selects the highest load pressure and feeds it back to the variable pump 2. The variable pump 2 dynamically adjusts the output flow rate according to the load to ensure smooth and powerful telescopic movement.

[0045] The operator sends a luffing command, and the control module sends an energizing command to the second switching valve 92, causing the valve core to switch direction and adjusting the second speed regulating valve 82 to set the luffing speed. High-pressure oil, after being regulated by the second speed regulating valve 82, enters the corresponding chamber of the luffing cylinder 14 through the second switching valve 92, driving the boom to rise or fall. Return oil from the luffing cylinder 14 flows back to the oil tank 1 through the second switching valve 92. The second one-way valve 112 collects the load pressure signal of the luffing cylinder 14 and feeds it back to the shuttle valve 12. The variable pump 2 adjusts its output according to the load, ensuring stable luffing action and avoiding fluctuations in luffing speed due to load changes.

[0046] The operator sends a swing command, and the control module sends an energizing command to the third switching valve 93, connecting the oil circuits of the second control valve group 5 and the third control valve group 6. Simultaneously, it sends an energizing command to the fourth switching valve 94, causing the valve core to reverse and adjusting the swing speed set by the third speed regulating valve 83. High-pressure oil, after its flow is limited by the first flow valve 101, enters the third control valve group 6 through the third switching valve 93. After being regulated by the third speed regulating valve 83, it enters the corresponding chamber of the swing cylinder 15 through the fourth switching valve 94, driving the platform to swing left and right. The return oil from the swing cylinder 15 flows back to the oil tank 1 through the fourth switching valve 94. The fourth one-way valve 114 collects the load pressure signal of the swing cylinder 15 and transmits it to the second flow valve 102. The second flow valve 102 dynamically adjusts the output flow to ensure smooth swinging motion.

[0047] Angle sensor 17 continuously transmits platform tilt signals to the control module. The control module compares the detected signals with the horizontal target value. If a tilt deviation exists, it calculates the required action direction and flow rate for leveling using a PID algorithm. The control module sends a reversing command to the fifth switching valve 95 to determine the extension / retraction direction of the leveling cylinder 16, and simultaneously sends an electronic control command to the fourth speed control valve 84 to adjust the output flow rate. After being distributed by the second flow valve 102, the high-pressure oil is regulated by the fourth speed control valve 84 and enters the corresponding chamber of the leveling cylinder 16 through the fifth switching valve 95, driving the piston rod to extend and retract, compensating for the platform tilt angle. During the leveling process, angle sensor 17 provides real-time feedback of the adjusted tilt signal, and the control module dynamically corrects the commands until the platform returns to level. The fifth one-way valve 115 collects the load pressure signal of the leveling cylinder 16 and feeds it back to the second flow valve 102. The second flow valve 102 maintains a stable flow rate to avoid speed fluctuations during the leveling process.

[0048] After the operation is completed, the operator sends a stop command, and the control module sends a power-off command to each switch valve. The valve cores reset under the action of the return springs, and each actuator stops operating. The sixth switch valve 96 is de-energized, the system switches to unloading mode, and the high-pressure oil output from the variable pump 2 flows directly back to the oil tank 1. The control module controls the leveling cylinder 16 to reset, restoring the platform to its initial level state. The angle sensor 17 continuously monitors to ensure accurate reset. Subsequently, the system power is turned off, the variable pump 2 stops operating, and the entire system enters a shutdown state.

[0049] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An electro-hydraulic leveling system for aerial work platforms, characterized in that, The system includes a main inlet pipe, a main return pipe, a power input assembly, a first control valve group (4), a second control valve group (5), a third control valve group (6), an actuator, a detection module, and a control module. The power input assembly provides hydraulic power to the system, and its outlet is connected to the inlet of the first control valve group (4) and the inlet of the second control valve group (5) through pipelines, forming a pipeline layout in which the first control valve group (4) and the power input assembly are connected in parallel, and the second control valve group (5) and the third control valve group (6) are connected in series. The actuator includes a telescopic cylinder (13) for realizing the telescopic movement of the platform, a luffing cylinder (14) for realizing the luffing movement of the platform, a swing cylinder (15) for realizing the swaying movement of the platform, and a leveling cylinder for realizing the leveling movement of the platform. (16), wherein the telescopic cylinder (13) and the luffing cylinder (14) are respectively connected to the working oil port of the second control valve group (5), and the swing cylinder (15) and the leveling cylinder (16) are respectively connected to the working oil port of the third control valve group (6). The detection module includes an angle sensor (17), which is used to collect the tilt state of the platform in real time. The angle sensor (17) is electrically connected to the control module and transmits the tilt signal. The control module (18) is electrically connected to the first control valve group (4), the second control valve group (5), and the third control valve group (6). By receiving the signal from the angle sensor (17) and outputting control commands, it drives each control valve group to work together, thereby controlling the actuator to complete the telescopic, luffing, swinging and leveling actions.

2. The electro-hydraulic leveling system for aerial work platforms according to claim 1, characterized in that, The power input assembly includes an oil tank (1), a variable pump (2), and a filter (3); the oil outlet of the oil tank (1) is connected to the oil inlet of the variable pump (2) through a main oil inlet pipe, and the oil outlet of the variable pump (2) is connected to the oil inlet of the filter (3) through a pipeline; the oil outlet of the filter (3) is connected to two oil outlet pipelines.

3. The electro-hydraulic leveling system for aerial work platforms according to claim 2, characterized in that, The first control valve group (4) includes a sixth switch valve (96) and a shuttle valve (12). The first oil outlet of the filter (3) is connected to the first oil inlet of the sixth switch valve (96). The oil outlet of the sixth switch valve (96) is connected to the first oil inlet of the shuttle valve (12). The oil outlet of the shuttle valve (12) is connected to the pressure feedback port of the variable pump (2) through a pipeline. The second oil inlet of the sixth switch valve (96) is connected to the main return oil pipe.

4. The electro-hydraulic leveling system for aerial work platforms according to claim 3, characterized in that, The second valve group (5) includes a first relief valve (71), a first speed control valve (81), a first switching valve (91), a first flow valve (101), and a first check valve (111). The inlet of the first speed control valve (81) is connected to the second outlet of the filter (3), the outlet of the first speed control valve (81) is connected to the inlet of the first switch valve (91), the two working ports of the first switch valve (91) are respectively connected to the rodless chamber and the rod chamber of the telescopic cylinder (13) through pipelines, and the outlet of the first switch valve (91) is connected to the main return oil pipe through pipelines; the inlet of the first check valve (111) is connected to the pipeline between the outlet of the first speed control valve (81) and the inlet of the first switch valve (91), and the outlet of the first check valve (111) is connected to the second inlet of the shuttle valve (12) through pipelines; The inlet of the first overflow valve (71) is connected to the second outlet of the filter (3). The first overflow valve (71) is connected in parallel with the first speed control valve (81). The outlet of the first overflow valve (71) is connected to the main return oil pipe through a pipeline.

5. The electro-hydraulic leveling system for aerial work platforms according to claim 4, characterized in that, The second valve group (5) also includes a second speed control valve (82), a second switching valve (92), a second check valve (112), a first flow valve (101), a third switching valve (93) and a third check valve (113). The first speed control valve (81) and the second speed control valve (82) are connected in parallel. The oil inlet of the second speed control valve (82) is connected to the second oil outlet of the filter (3). The oil outlet of the second speed control valve (82) is connected to the oil inlet of the second switch valve (92). The two working oil ports of the second switch valve (92) are respectively connected to the rodless chamber and the rod chamber of the luffing cylinder (14) through pipelines. The oil outlet of the second switch valve (92) is connected to the main return oil pipe through pipelines. The oil inlet of the second check valve (112) is connected to the pipeline between the oil outlet of the second speed regulating valve (82) and the oil inlet of the second switching valve (92), and the oil outlet of the second check valve (112) is connected to the second oil inlet of the shuttle valve (12) through the pipeline. The inlet of the first flow valve (101) is connected to the second outlet of the filter (3). The outlet of the first flow valve (101) is connected to the inlet of the third switch valve (93). The inlet of the third check valve (113) is connected to the pipeline between the outlet of the first flow valve (101) and the inlet of the third switch valve (93). The third check valve (113) and the third switch valve (93) are connected in parallel. The outlet of the third check valve (113) is connected to the second inlet of the shuttle valve (12) through a pipeline.

6. The electro-hydraulic leveling system for aerial work platforms according to claim 5, characterized in that, The third control valve group (6) includes a third speed control valve (83) and a fourth switching valve (94); the oil inlet of the third speed control valve (83) is connected to the oil outlet pipeline of the third switching valve (93), the oil outlet of the third speed control valve (83) is connected to the oil inlet of the fourth switching valve (94), the two working oil ports of the fourth switching valve (94) are respectively connected to the two chambers of the swing cylinder (15) through pipelines, and the oil outlet of the fourth switching valve (94) is connected to the main return oil pipe through pipelines.

7. The electro-hydraulic leveling system for aerial work platforms according to claim 6, characterized in that, The third control valve group (6) also includes a fourth speed control valve (84) and a fifth switching valve (95). The oil inlet of the fourth speed control valve (84) is connected to the oil outlet pipeline of the third switching valve (93). The third speed control valve (83) and the fourth speed control valve (84) are set in parallel. The oil outlet of the fourth speed control valve (84) is connected to the oil inlet of the fifth switching valve (95). The two working oil ports of the fifth switching valve (95) are respectively connected to the rodless chamber and the rod chamber of the leveling cylinder (16) through pipelines. The oil outlet of the fifth switching valve (95) is connected to the main return oil pipe through pipelines.

8. The electro-hydraulic leveling system for aerial work platforms according to claim 7, characterized in that, The third control valve group (6) also includes the second relief valve (72), the second flow valve (102), the fourth check valve (114) and the fifth check valve (115). The inlet of the second overflow valve (72) is connected to the outlet pipeline of the third switch valve (93). The second overflow valve (72) and the third speed control valve (83) are connected in parallel. The outlet of the first overflow valve (71) is connected to the main return oil pipe through a pipeline. The second flow valve (102) is connected to the oil outlet pipeline of the third switch valve (93). The second flow valve (102) and the second relief valve (72) are connected in parallel. The oil outlet of the second flow valve (102) is connected back to the main return oil pipe through a pipeline. The inlet of the fourth check valve (114) is connected to the pipeline between the outlet of the third speed control valve (83) and the inlet of the fourth switch valve (94). The inlet of the fifth check valve (115) is connected to the pipeline between the outlet of the fourth speed control valve (84) and the inlet of the fifth switch valve (95). The outlets of both the fourth check valve (114) and the fifth check valve (115) are connected to the feedback end of the second flow valve (102) through pipelines.

9. The electro-hydraulic leveling system for aerial work platforms according to claim 2, characterized in that, The opening ends of both the main oil inlet pipe and the main oil return pipe are located inside the oil tank (1).

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