Boom type aerial work platform

Abstract

The present invention relates to an arm-type aerial work platform, and is intended to solve the shortcomings of the travel system of the existing arm-type aerial work platform; a arm-type aerial work platform is provided, wherein a closed high-pressure variable pump in the power system includes a working pump and a displacement control valve for controlling the displacement of the working pump; the output shaft of the reduction box in the chassis travel system is simultaneously connected to the integral front and rear drive axles through a transmission shaft, the output shaft of the drive motor is connected to the input shaft of the reduction box, and the drive motor is connected to the working pump through a pipeline to form a closed hydraulic circuit; the control system includes a whole machine controller connected to the displacement control valve of the working pump and the engine speed controller. The chassis parts of the arm-type aerial work platform of the present invention are highly interchangeable, the difficulty of assembly and maintenance is low, the design of the whole machine system is simplified, the processing difficulty and cost of the structural parts are reduced, and the layout of the whole vehicle is easy.

Description

Technical Field

[0001] The present invention relates to an aerial work platform, and more particularly to a boom-type aerial work platform. Background Art

[0002] The hydraulic travel system is widely used in construction machinery due to its large output torque and high power density. At present, the boom-type aerial work platform in the industry adopts an integral chassis, with four hydraulic motors installed on both sides of the chassis to control the wheels in conjunction with four travel reducers. If you want to achieve infinitely variable speed, you need four variable motors to work with four travel reducers, which is expensive.

[0003] The existing hydraulic travel systems mentioned above mainly have the following problems: poor differential performance when turning, which can easily cause the whole machine to shake when turning in a large range; the turning radius of the multi-motor travel hydraulic system is too large, making it difficult to transfer short distances; insufficient oil supply to the motor on the outside of the curve during turning, resulting in motor air suction, cavitation and other phenomena, which seriously affect the reliability of the hydraulic travel system. In addition, the travel control valve to the travel motor high and low speed control, brake control, plus the travel motor's own oil inlet pipe, return pipe, and leakage pipe, the control of a single motor requires five hoses, the longest of which is nearly three meters long, and four-wheel drive requires twenty hoses, which takes up a lot of space on the chassis and greatly increases the difficulty of assembly and maintenance.

[0004] It should be noted that the information disclosed in the background technology section of the present invention is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a boom-type aerial work platform in view of the shortcomings of the existing boom-type aerial work platform walking system, which simplifies the design of the single whole system, reduces the difficulty and cost of structural parts processing, facilitates the layout of the whole vehicle, and improves the walking stability.

[0006] The technical solution of the present invention to achieve its purpose is as follows: provide a boom-type aerial work platform, including a power system, a chassis travel system, and a control system; the power system includes an engine, a hydraulic oil tank, and a closed high-pressure variable pump driven by the engine; the closed high-pressure variable pump includes a working pump whose oil suction port is connected to the hydraulic oil tank, and a displacement control valve for controlling the displacement of the working pump; the characteristics are:

[0007] The chassis travel system includes a vehicle chassis, an integral front drive axle and a rear drive axle installed on the vehicle chassis, a reduction gearbox, and a drive motor; the output shaft of the reduction gearbox is connected to the front drive axle and the rear drive axle through a transmission shaft, the output shaft of the drive motor is connected to the input shaft of the reduction gearbox, and the drive motor is connected to the working pump through a pipeline to form a closed hydraulic circuit;

[0008] The control system includes a whole machine controller and an operating device for outputting a manual signal in response to a user operation. The displacement control valve of the working pump and the engine speed controller are electrically connected to the whole machine controller.

[0009] The present invention adopts a complete vehicle chassis and an integral drive axle to improve the interchangeability of chassis parts, reduce the difficulty of assembly and maintenance, simplify the design of the whole machine system, reduce the difficulty and cost of processing structural parts, and facilitate the layout of the whole vehicle; the mechanical differential of the drive axle has high reliability, improves the walking stability, effectively overcomes the slip phenomenon, and makes the driving effect better. The closed hydraulic power source composed of a high-pressure variable pump and a drive motor is equipped with a reduction box to enlarge the driving speed adjustment range, while reducing the cost and simplifying the hydraulic pipeline under the condition of meeting the four-wheel drive.

[0010] In the above-mentioned boom-type aerial work platform, the closed high-pressure variable pump also includes an oil replenishment pump and a one-way oil replenishment valve; the oil suction port of the oil replenishment pump is connected to the hydraulic oil tank, the pump port of the oil replenishment pump is connected to the oil inlet end of the one-way oil replenishment valve, and the two oil replenishment outlets of the one-way oil replenishment valve are respectively connected to the two working ports of the working pump.

[0011] In the above-mentioned boom-type aerial work platform, the closed high-pressure variable displacement pump also includes an oil replenishment filter, and two ends of the oil replenishment filter are respectively connected to the pump port of the oil replenishment pump and the oil inlet end of the oil replenishment valve.

[0012] In the above-mentioned boom-type aerial work platform, the closed high-pressure variable pump also includes a one-way oil replenishment overflow valve, the oil inlet end of the one-way oil replenishment overflow valve is connected to the oil inlet end of the oil replenishment valve, and is connected to the hydraulic oil tank through an oil return filter.

[0013] In the above-mentioned boom-type aerial work platform, the driving motor includes a variable motor, a variable motor control valve for controlling the variable motor, and a shuttle valve whose two oil inlet ends are respectively connected to the two working ports of the variable motor, and the electromagnetic coil of the variable motor control valve is connected to the whole machine controller; the oil outlet end of the shuttle valve is connected to the oil inlet end of the variable motor control valve. The hydraulic travel system can shift gears while the variable motor has power, realizing load shifting of the variable motor.

[0014] In the above-mentioned boom-type aerial work platform, the front drive axle is hinged on the vehicle chassis, two floating cylinders are installed between the front drive axle and the vehicle chassis, and a floating cylinder balance valve is arranged on the floating cylinder. The floating cylinder balance valve is connected to the floating bridge solenoid valve, the electromagnetic coil of the floating bridge solenoid valve is connected to the whole machine controller, and the oil inlet end of the floating bridge solenoid valve is connected to the oil outlet end of the shuttle valve.

[0015] In the above-mentioned boom-type aerial work platform, the chassis travel system also includes a braking system, which includes brakes installed at both ends of the front drive axle and the rear drive axle, and a brake solenoid valve connected to the brake. The electromagnetic coil of the brake solenoid valve is connected to the whole machine controller, and the oil inlet end of the brake solenoid valve is connected to the oil outlet end of the shuttle valve. In the present invention, the brake is a normally closed brake. When no pressure oil flows to the brake through the brake solenoid valve, the brake is in a braking state. When the boom-type aerial work platform does not move, the shuttle valve cannot draw out pressure oil from the two working oil ports of the variable motor to act on the brake through the brake solenoid valve, that is, the brake cannot be released, ensuring safety. When the boom-type aerial work platform is moving and the operator does not perform a braking action, the brake solenoid valve is in a conducting state, and the shuttle valve draws out pressure oil from the two working oil ports of the variable motor to act on the brake through the brake solenoid valve to release the brake. When the operator steps on the brake pedal, the brake solenoid valve is powered off and the brake cylinder is connected to the return oil port to release the pressure, thereby achieving brake braking. In the present invention, by introducing the pressure oil for releasing the brake from the working oil port of the variable pump and adopting the normally closed brake, automatic braking when stopping and automatic releasing the brake when moving are realized, thereby improving the safety of the boom-type aerial work platform.

[0016] In the above-mentioned boom-type aerial work platform, an adjustable pressure reducing valve is connected in series in the connecting oil circuit between the oil inlet end of the brake solenoid valve and the oil outlet end of the shuttle valve.

[0017] In the above-mentioned boom-type aerial work platform, the driving motor further includes a two-way overflow valve whose two ends are respectively connected to the two working ports of the variable motor, and a balancing valve connected between the two working ports of the variable motor.

[0018] In the above-mentioned boom-type aerial work platform, the control system also includes a torque sensor for measuring the torque of the variable motor output shaft, and the torque sensor is connected to the controller.

[0019] Compared with the prior art, the chassis parts of the boom-type aerial work platform of the present invention are highly interchangeable, the difficulty of assembly and maintenance is low, the design of the whole system is simplified, the processing difficulty and cost of the structural parts are reduced, and the layout of the whole vehicle is easy; the mechanical differential provided by the drive axle has high reliability, improved walking stability, effectively overcomes the slipping phenomenon, reduces the cost while meeting the four-wheel drive condition, and simplifies the hydraulic pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a hydraulic principle diagram of the walking system of the boom-type aerial work platform of the present invention.

[0021] Figure 2 This is the hydraulic principle diagram of the closed high-pressure variable pump in the present invention.

[0022] Figure 3 This is the hydraulic principle diagram of the drive motor of the present invention.

[0023] Figure 4 This is the hydraulic principle diagram of the electromagnetic hydraulic valve block of the present invention.

[0024] Figure 5 It is a block diagram of the control system of the boom-type aerial work platform of the present invention.

[0025] Parts names and serial numbers in the figure:

[0026] Hydraulic oil tank 1, oil suction filter 2, oil return filter 3, closed high-pressure variable pump 4, center swivel joint 5, travel drive motor 6, wheels 7, vehicle chassis 8, reduction box 9, rear drive axle 10, transmission shaft 11, brake 12, floating cylinder balance valve 13, front drive axle 14, floating cylinder 15, electromagnetic hydraulic valve block 16.

[0027] A charge pump 401 , a working pump 402 , a diesel engine 403 , a one-way charge valve 404 , a one-way charge overflow valve 405 , a displacement control valve 406 , and a charge filter 407 .

[0028] Variable motor 601 , torque sensor 602 , two-way relief valve 603 , balance valve 604 , shuttle valve 605 , variable motor control valve 606 .

[0029] Floating bridge solenoid valve 1601, brake solenoid valve 1602, adjustable pressure reducing valve 1603. DETAILED DESCRIPTION

[0030] The specific implementation scheme is described below with reference to the accompanying drawings.

[0031] The walking system of the boom type aerial work platform in the present invention is as follows Figure 1 As shown, it includes a power system, a chassis traveling system, and a control system.

[0032] The power system includes an engine 403, a hydraulic oil tank 1, and a closed high-pressure variable pump 4. Figure 2 As shown, the closed high-pressure variable pump 4 includes a working pump 401, a displacement control valve 406, an oil replenishment pump 401, a one-way oil replenishment valve 404, an oil replenishment filter 407, and a one-way oil replenishment overflow valve 405. The displacement control valve 406 is a double-nozzle flapper solenoid valve.

[0033] The working pump 402 and the oil replenishing pump 401 are connected in series and connected to the diesel engine 403 through a transmission shaft to obtain motive power.

[0034] like Figure 1 Figure 2 As shown, the hydraulic oil tank 1 is provided with two oil outlets and two oil return ports. The displacement of the working pump 402 is controlled by a displacement control valve 406. The leakage oil port T' of the working pump 402 is directly connected to the hydraulic oil tank 1 through a high-pressure hose; the suction port S of the supplementary oil pump 401 is connected to the hydraulic oil tank 1 through an oil suction filter 2.

[0035] The pump port of the oil replenishment pump 401 is connected to the oil inlet end of the one-way oil replenishment valve 404, and the two oil replenishment outlets of the one-way oil replenishment valve 404 are respectively connected to the working port A and the working port B of the working pump 402. The two ends of the oil replenishment filter 407 are respectively connected to the pump port of the oil replenishment pump 401 and the oil inlet end of the one-way oil replenishment valve 404. The oil inlet end of the one-way oil replenishment relief valve 405 is connected to the oil inlet end of the one-way oil replenishment valve 404, and the oil outlet end is connected to the return oil port T of the closed high-pressure variable pump 4, and the return oil port T of the closed high-pressure variable pump 4 is connected to the hydraulic oil tank through the return oil filter 3.

[0036] The chassis running system includes a vehicle chassis 8, an integral front drive axle 14 and a rear drive axle 10 installed on the vehicle chassis 8, a reduction gearbox 9, and a drive motor 6. The output shaft of the reduction gearbox 9 is connected to the front drive axle 14 and the rear drive axle 10 through a transmission shaft 11. The front drive axle 14 and the rear drive axle 10 are equipped with differentials to achieve the differential between the inner and outer wheels 7 when the drive axle turns.

[0037] like Figure 3As shown, the drive motor 6 includes a variable motor 601, a variable motor control valve 606, a shuttle valve 605, a two-way relief valve 603, and a balance valve 604. The variable motor control valve 606 is used to control the displacement of the variable motor 601, thereby changing the output torque of the variable motor 601. The two ends of the two-way relief valve 603 are respectively connected to the two working ports of the variable motor 601, and the control end is connected to the oil return port T of the drive motor 6. The balance valve 604 is connected between the two working ports of the variable motor 601. The two oil inlet ends of the shuttle valve 605 are respectively connected to the two working ports of the variable motor 601. The variable motor control valve 606 is a two-position three-way solenoid valve, whose oil inlet end is connected to the oil outlet end of the shuttle valve 605, the oil return end is connected to the oil return port T of the drive motor 6, and the oil outlet is connected to the displacement adjustment cylinder of the variable motor 601.

[0038] like Figure 1 As shown, the working oil port A and the working oil port B of the variable motor 601 are connected to the working port A and the working port B of the working pump 402 through a high-pressure hose and a central rotary joint 5 to form a closed loop.

[0039] like Figure 1 As shown, the front drive axle 14 is hinged on the vehicle chassis 8, two floating cylinders 15 are installed between the front drive axle 14 and the vehicle chassis 8, and a floating cylinder balance valve 13 is provided on the floating cylinder 15. The floating cylinder balance valve 13 is connected to the floating bridge solenoid valve 1601, and the oil inlet end of the floating bridge solenoid valve 1601 is connected to the oil outlet end of the shuttle valve 605.

[0040] The chassis travel system also includes a braking system, which includes a brake 12 installed at both ends of the front drive axle 14 and the rear drive axle 10, a brake solenoid valve 1602 connected to the brake 12, and an adjustable pressure reducing valve 1603, wherein the oil inlet end of the brake solenoid valve 1602 is connected to the oil outlet end of the shuttle valve 605. The adjustable pressure reducing valve 1603 is connected in series between the brake solenoid valve 1602 and the oil outlet end of the shuttle valve 65, that is, the two ends of the adjustable pressure reducing valve 1603 are connected to the oil inlet end of the brake solenoid valve 1602 and the oil outlet end of the shuttle valve 605, respectively.

[0041] In this embodiment, the floating bridge solenoid valve 1601, the brake solenoid valve 1602, and the adjustable pressure reducing valve 1603 are integrated in the electromagnetic hydraulic valve block 16, and the output pressure of the adjustable pressure reducing valve 1603 can be adjusted according to the brake pressure of the brake 12. The floating bridge solenoid valve 1601 is a two-position four-way valve, and the brake solenoid valve 1602 is a two-position two-way valve. The valve block is provided with a total oil inlet P, and the oil inlet end of the floating bridge solenoid valve 1601 and the oil inlet end of the brake solenoid valve 1602 are connected to the total oil inlet P. The oil return ports of the floating bridge solenoid valve 1601 and the brake solenoid valve 1602 are connected, and are connected to the total oil return port T of the valve block. The total oil inlet P of the electromagnetic hydraulic valve block 16 is connected to the OUT port of the drive motor 6 through a high-pressure hose, and the OUT port of the drive motor 6 is connected to the oil outlet end of the shuttle valve 605. The oil port C of the brake solenoid valve 1602 is connected to the four hydraulic brakes 12. The oil outlet of the floating bridge solenoid valve 1601 is connected to the floating cylinder balance valve 13, wherein the oil outlet A is connected to the control end of the floating cylinder balance valve 13, and the oil outlet B is connected to the oil return port of the floating cylinder balance valve. The oil return port of the brake solenoid valve 1602 and the oil return port of the floating bridge solenoid valve 1601 are connected to the total oil return port T of the electromagnetic hydraulic valve block, and the total oil return port T of the electromagnetic hydraulic valve block 16 is connected to the leakage oil port of the variable motor 604, and then connected to the oil port of the central rotary joint 5, and finally connected to the hydraulic oil tank 1.

[0042] like Figure 5 As shown, the control system includes a whole machine controller 17 , an operating device 18 , and a torque sensor 602 .

[0043] The torque sensor 602 is connected to the whole machine controller 17, and the torque sensor 602 is used to measure the torque of the variable motor output shaft.

[0044] The operating device 18 is connected to the whole machine controller 17 and is used to respond to user operations and output manual signals so that the operator can realize the enabling, forward walking, backward walking, braking, floating bridge opening and other actions of the boom-type aerial work platform through the operating device 18.

[0045] The whole machine controller 17 includes at least five switch input ports and two analog input ports; the enable signal, forward signal, reverse signal, floating bridge opening signal, and brake signal of the operating device 18 are connected to the switch input end of the whole machine controller; the torque sensor and the accelerator pedal signal are connected to the analog input end of the whole machine controller; the output end of the whole machine controller is connected to the electromagnetic coils of each electromagnetic valve and the diesel engine speed controller. The electromagnetic valve includes the displacement control valve 406, the variable motor control valve 606, the floating bridge electromagnetic valve 1601, and the brake electromagnetic valve 1602 in the closed high-pressure variable pump. The displacement control valve 406 and the variable motor control valve 606 are proportional electromagnetic valves, and the floating bridge electromagnetic valve 1601 and the brake electromagnetic valve 1602 are switch electromagnetic valves.

[0046] like Figures 1 to 5 As shown, in the boom-type aerial work platform of the present invention, when the diesel engine 403 is started, all solenoid valves are de-energized, the boom-type aerial work platform is in a braking state, the working pump 402 and the variable motor 604 perform internal circulation with a very small displacement, and the flow of the oil replenishment pump 401 also returns to the hydraulic oil tank through the one-way oil replenishment overflow valve 405.

[0047] Taking the forward movement of the boom-type aerial work platform as an example, the operating device 18 outputs an enable signal and a forward signal at this time, and outputs an accelerator pedal signal to control the proportional electromagnet E1 of the displacement control valve 406 according to the force applied to the accelerator pedal. The forward movement of the walking hydraulic system includes the following processes: the working pump 401 provides power for the variable motor 601; after the output end of the variable motor 401 is connected to the reduction box 9, the power is transmitted to the front drive axle 14 and the rear drive axle 10 through the transmission shaft 11, thereby completing the forward movement of the aerial work platform. At the same time, the electromagnet E4 of the brake solenoid valve 1602 is energized, and the shuttle valve 605 introduces high-pressure oil from the working oil port of the variable motor 601, which acts on the oil cylinder of the brake 12 through the adjustable pressure reducing valve 1603 and the brake solenoid valve 1602, so that each brake oil cylinder overcomes the spring elastic force and realizes brake release.

[0048] When acceleration or deceleration is required, the whole machine controller 17 receives different throttle output signals according to the force applied to the throttle pedal, and after calculation, outputs a control signal proportionally to the proportional solenoid E1 of the displacement control valve 406, thereby changing the displacement of the working pump. At the same time, the diesel engine speed controller also receives a signal, and increases or decreases the speed of the diesel engine according to the different throttle output signals, thereby realizing stepless speed change of the walking system of the boom-type aerial work platform.

[0049] During walking, when the working load of the variable motor 601 changes, the torque sensor 602 installed on the output shaft of the variable motor 601 detects the real-time torque and transmits the signal to the whole machine controller 17. After calculation, the whole machine controller 17 outputs the control signal to the proportional solenoid E5 of the variable motor control valve 606. A certain proportion of the controlled hydraulic oil enters the rodless chamber of the variable cylinder, changing the displacement of the variable motor 601, and then changing the output torque of the drive motor 6 to adapt to the change of the working load, thereby realizing automatic gear shifting during walking.

[0050] During the walking process, the operator can output the floating bridge opening signal and the braking signal through the operating device 18. When the floating bridge opening signal is output, the switch electromagnet E3 of the floating bridge solenoid valve 1601 is energized, the floating bridge solenoid valve 1601 is opened and works in the left position, and the hydraulic oil from the shuttle valve 605 acts on the control end of the floating cylinder balance valve 13 through the floating bridge solenoid valve 1601. At the same time, the return oil port of the floating cylinder balance valve 13 is connected to the hydraulic oil tank through the floating bridge solenoid valve 1601, the return oil port T of the electromagnetic hydraulic valve block 16, and the center rotary joint, so that the large cavity and the small cavity of the floating cylinder 15 are connected to achieve floating. When the braking signal is output, the whole machine controller 18 will make the electromagnet E4 of the brake solenoid valve 1602 lose power, the brake solenoid valve 1602 works in the right position, the brake 12 is opened, and the brake 12 is in a braking state under the elastic force of its internal spring. At the same time, other solenoid valves are also not energized, the boom-type aerial work platform is in a braking state, the diesel engine speed controller controls the diesel engine to be in an idle state, the working pump 402 performs internal circulation with a very small displacement, and the flow of the oil replenishment pump also returns to the hydraulic oil tank through the oil replenishment overflow valve.

[0051] Compared with the prior art, the chassis parts of the boom-type aerial work platform of the present invention are highly interchangeable, the difficulty of assembly and maintenance is low, the design of the whole system is simplified, the processing difficulty and cost of the structural parts are reduced, and the layout of the whole vehicle is easy; the mechanical differential provided by the drive axle has high reliability, improved walking stability, effectively overcomes the slipping phenomenon, reduces the cost while meeting the four-wheel drive condition, and simplifies the hydraulic pipeline.

Claims

1. A boom-type aerial work platform, comprising a power system, a chassis travel system, and a control system; the power system comprises an engine, a hydraulic oil tank, and a closed high-pressure variable pump driven by the engine; the closed high-pressure variable pump comprises a working pump whose oil suction port is connected to the hydraulic oil tank, and a displacement control valve for controlling the displacement of the working pump; Features: The chassis travel system includes a vehicle chassis, an integral front drive axle and a rear drive axle installed on the vehicle chassis, a reduction gearbox, a drive motor, and a brake system; the output shaft of the reduction gearbox is connected to the front drive axle and the rear drive axle through a transmission shaft, the output shaft of the drive motor is connected to the input shaft of the reduction gearbox, and the drive motor is connected to the working pump through a pipeline to form a closed hydraulic circuit; The control system includes a whole machine controller, an operating device for outputting a manual signal in response to a user operation, and the displacement control valve of the working pump and the engine speed controller are electrically connected to the whole machine controller; The driving motor comprises a variable motor, a variable motor control valve for controlling the variable motor, and a shuttle valve whose two oil inlet ends are respectively connected to the two working ports of the variable motor; the electromagnetic coil of the variable motor control valve is connected to the whole machine controller; the oil outlet end of the shuttle valve is connected to the oil inlet end of the variable motor control valve; The braking system includes brakes installed at both ends of the front drive axle and the rear drive axle, and brake solenoid valves connected to the brakes. The electromagnetic coil of the brake solenoid valve is connected to the whole machine controller, and the oil inlet end of the brake solenoid valve is connected to the oil outlet end of the shuttle valve; an adjustable pressure reducing valve is connected in series on the connecting oil line between the oil inlet end of the brake solenoid valve and the oil outlet end of the shuttle valve; the brake is a normally closed brake.

2. The boom-type aerial work platform according to claim 1, characterized in that; The closed high-pressure variable pump also includes an oil replenishment pump and a one-way oil replenishment valve; the oil suction port of the oil replenishment pump is connected to the hydraulic oil tank, the pump port of the oil replenishment pump is connected to the oil inlet end of the one-way oil replenishment valve, and the two oil replenishment outlets of the one-way oil replenishment valve are respectively connected to the two working ports of the working pump.

3. The boom-type aerial work platform according to claim 2, characterized in that The closed high-pressure variable pump further comprises an oil replenishment filter, and two ends of the oil replenishment filter are respectively connected to the pump port of the oil replenishment pump and the oil inlet end of the one-way oil replenishment valve.

4. The boom-type aerial work platform according to claim 3, characterized in that The closed high-pressure variable pump also includes a one-way oil replenishment relief valve, the oil inlet end of the one-way oil replenishment relief valve is connected to the oil inlet end of the oil replenishment valve, and the oil outlet end is connected to the hydraulic oil tank through an oil return filter.

5. The boom-type aerial work platform according to claim 1, characterized in that The front drive axle is hinged on the vehicle chassis, two floating cylinders are installed between the front drive axle and the vehicle chassis, and a floating cylinder balancing valve is arranged on the floating cylinder. The floating cylinder balancing valve is connected to a floating bridge solenoid valve, and the electromagnetic coil of the floating bridge solenoid valve is connected to the whole machine controller, and the oil inlet end of the floating bridge solenoid valve is connected to the oil outlet end of the shuttle valve.

6. The boom-type aerial work platform according to claim 5, characterized in that The driving motor further comprises a two-way overflow valve whose two ends are respectively connected to the two working ports of the variable motor, and a balance valve connected between the two working ports of the variable motor.

7. The boom-type aerial work platform according to claim 1, characterized in that The control system further comprises a torque sensor for measuring the torque of the output shaft of the variable motor, wherein the torque sensor is connected to the controller.

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