Aerial work platform and hydraulic system thereof

Abstract

The utility model discloses an aerial work platform and a hydraulic system thereof, and the hydraulic system comprises a steering oil cylinder loop which comprises a steering reversing valve used for controlling a steering oil cylinder; the steering oil cylinder loop comprises a steering oil tank, a steering reversing valve and a walking motor loop, oil is taken from the middle position of the steering reversing valve, the steering oil cylinder loop further comprises a steering valve oil return oil way and a bypass oil return oil way, and the steering valve oil return oil way is connected to the hydraulic oil tank from an oil return opening of the steering reversing valve and is provided with an oil return one-way valve for preventing backflow; and the bypass oil return path bypasses the hydraulic oil tank from the steering valve oil return path between the oil return port of the steering reversing valve and the oil return one-way valve, and is provided with a stop valve for controlling the on or off of the bypass oil return path. The oil return path of the steering oil cylinder loop is optimized, so that the oil return path is shortened, oil return through the walking motor loop is not needed, the oil is directly returned to the hydraulic oil tank through the additionally arranged bypass oil return path, and the oil return loss and the system energy consumption are reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of aerial work, and specifically, relates to an aerial work platform and a hydraulic system thereof. Background Art

[0002] Scissor-type aerial work platforms always have the problem of high energy consumption during operation. For example, the hydraulic actuator of the aerial work platform generally includes a steering cylinder and a travel motor. The circuits of the two coexist in the system, which often causes large oil return losses in the system. In addition, when the ground is uneven or slippery during driving, one side of the travel motor often slips and idles, which causes the equipment to fail to drive normally. These feedbacks show that there are certain design defects in the hydraulic control system, which need to be overcome urgently. Summary of the invention

[0003] The purpose of the present application is to provide an aerial work platform and a hydraulic system thereof to reduce oil return loss and lower energy consumption.

[0004] According to a first aspect of the present application, a hydraulic system for an aerial work platform is provided, comprising:

[0005] A steering cylinder circuit, including a steering reversing valve for controlling a steering cylinder; and

[0006] The travel motor circuit takes oil from the middle position of the steering reversing valve;

[0007] Wherein, the steering cylinder circuit also includes:

[0008] A steering valve oil return circuit, connected from the oil return port of the steering reversing valve to the hydraulic oil tank and provided with an oil return check valve to prevent backflow; and

[0009] A bypass oil return circuit bypasses the steering valve oil return circuit between the oil return port of the steering reversing valve and the oil return check valve to the hydraulic oil tank and is provided with a stop valve for controlling the conduction or cutoff of the bypass oil return circuit.

[0010] In some embodiments, the steering cylinder circuit further comprises:

[0011] Hydraulic pumps;

[0012] A steering valve oil inlet oil circuit, connected from the oil outlet of the hydraulic pump to the oil inlet of the steering reversing valve;

[0013] Wherein, a flow valve is provided in the oil inlet circuit of the steering valve.

[0014] In some embodiments, the hydraulic system comprises:

[0015] The main reversing valve is arranged in the oil inlet circuit of the steering valve and is located between the oil outlet of the hydraulic pump and the flow valve.

[0016] In some embodiments, the first motor oil circuit includes a first motor reversing valve for controlling the first motor and a first compensation valve for maintaining a stable flow rate through the first motor reversing valve, and the second motor oil circuit includes a second motor reversing valve for controlling the second motor and a second compensation valve for maintaining a stable flow rate through the second motor reversing valve.

[0017] In some embodiments, the travel motor circuit includes:

[0018] An oil connection oil circuit, one end of which is connected to the oil return port of the steering reversing valve, and the other end of which is connected to the first motor oil circuit and the second motor oil circuit respectively; and

[0019] A motor oil return circuit, connected from the oil return port of the first motor reversing valve and the oil return port of the second motor reversing valve to the hydraulic oil tank;

[0020] Wherein, the oil extraction connecting oil circuit is provided with an oil extraction one-way throttle valve, and the motor oil return oil circuit is provided with an oil return one-way throttle valve.

[0021] In some embodiments, the oil extraction connection oil circuit is hydraulically connected to an oil outlet of the oil return one-way valve.

[0022] In some embodiments, the first motor circuit includes a first shuttle valve, two comparison oil ports of the first shuttle valve are respectively hydraulically connected to the two end oil ports of the first motor, and the shuttle valve oil outlet is connected to the first hydraulic control end of the first compensation valve; the second motor circuit includes a second shuttle valve, two comparison oil ports of the second shuttle valve are respectively hydraulically connected to the two end oil ports of the second motor, and the shuttle valve oil outlet is connected to the first hydraulic control end of the second compensation valve.

[0023] In some embodiments, the first compensation valve and the second compensation valve are both normally closed hydraulically controlled switch valves arranged before the motor reversing valve and include:

[0024] The first hydraulic control end is a spring end; and

[0025] a second hydraulic control end, hydraulically connected to a valve forward oil port of the motor reversing valve;

[0026] Wherein, the first hydraulic control end is hydraulically connected to the oil outlet of the shuttle valve to adjust the opening of the overflow valve port of the first compensation valve.

[0027] In some embodiments, the first motor reversing valve and the second motor reversing valve are spool valves.

[0028] According to a second aspect of the present application, an aerial work platform is also provided, and the aerial work platform includes the hydraulic system of the aerial work platform according to the present application.

[0029] In the aerial work platform and its hydraulic system of the present application, the oil return path of the steering cylinder circuit is optimized. The oil return of the steering cylinder no longer passes through the travel motor circuit, but is directly connected to the hydraulic oil tank through the bypass oil return line to reduce the oil return path and reduce the oil return loss. Among them, the on-off of the bypass oil return line can be controlled by setting a stop valve, and the conduction of the oil return line is controlled only when the steering cylinder needs to return oil, ensuring the safety of oil return and the reliability of the hydraulic system, thereby reducing system energy consumption and meeting the energy-saving requirements of electrified equipment.

[0030] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. In the drawings:

[0032] Figure 1 A hydraulic principle diagram of a hydraulic system of an aerial work platform according to a specific embodiment of the present application;

[0033] Figure 2 Pictured Figure 1 The oil flow direction of the hydraulic system in the steering state is shown, where the bold oil path represents the oil flow direction;

[0034] Figure 3 Pictured Figure 1 The diagram shows the oil flow direction of the hydraulic system in the traveling state, where the bold oil circuit represents the oil flow direction.

[0035] Description of Reference Numerals

[0036] 1 Motor 2 Hydraulic pump

[0037] 3 Filter 4 Main reversing valve

[0038] 5 Flow valve 6 Steering reversing valve

[0039] 7 Steering cylinder 8 First compensation valve

[0040] 9 First motor reversing valve 10 First shuttle valve

[0041] 11 First motor 12 Second motor

[0042] 13 Second shuttle valve 14 Second motor reversing valve

[0043] 15 Second compensation valve 16 Oil return one-way throttle valve

[0044] 17 Oil extraction one-way throttle valve 18 Stop valve

[0045] 19 Oil return check valve L1 Bypass oil return line

[0046] L2 Oil connection line L3 Motor oil return line DETAILED DESCRIPTION

[0047] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0048] The aerial work platform and its hydraulic system according to the present application are described below with reference to the accompanying drawings.

[0049] The hydraulic system of a scissor-type aerial work platform is generally simple, and the two travel motors in the travel oil circuit are simply connected in parallel. Therefore, if the ground is uneven or slippery during driving, it is easy to slip and even fail to drive normally. To this end, the application discloses a new hydraulic system for an aerial work platform, which includes:

[0050] A steering cylinder circuit, including a steering reversing valve 6 for controlling a steering cylinder 7; and

[0051] The travel motor circuit takes oil from the middle position of the steering reversing valve 6 and includes a first motor oil circuit and a second motor oil circuit arranged in parallel. The first motor oil circuit includes a first motor reversing valve 9 for controlling the first motor 11 and a first compensation valve 8 for maintaining a stable flow rate through the first motor reversing valve 9. The second motor oil circuit includes a second motor reversing valve 14 for controlling the second motor 12 and a second compensation valve 15 for maintaining a stable flow rate through the second motor reversing valve 14.

[0052] The present application aims to optimize the hydraulic system of a scissor-type aerial work platform by adding a compensating valve before the parallel motor circuit to ensure that the flow of the two motors is not affected by the motor load, that is, no matter how the load changes, the hydraulic flow to the first motor 11 and the second motor 12 remains basically unchanged, so that the left and right motors maintain a basically uniform speed and can move straight normally without slipping.

[0053] It is well known to those skilled in the art that in order to make the flow through the motor not be affected by the motor load, various flow control methods can be used, such as a flow valve control method combined with an electric control. Even if a compensation valve is used, there can be various structural forms. In this embodiment, a relatively simple compensation valve is used, such as Figure 1 As shown, the first motor circuit includes a first shuttle valve 10, and the two comparison oil ports of the first shuttle valve 10 are respectively hydraulically connected to the two end oil ports of the first motor 11, and the shuttle valve oil outlet is connected to the first hydraulic control end of the first compensation valve 8; similarly, the second motor circuit includes a second shuttle valve 13, and the two comparison oil ports of the second shuttle valve 13 are respectively hydraulically connected to the two end oil ports of the second motor 12, and the shuttle valve oil outlet is connected to the first hydraulic control end of the second compensation valve 15. In this way, once a motor slips and idles, and the load drops sharply, the motor flow increases and the pressure decreases, that is, the pressure at the shuttle valve oil outlet decreases, and then introduced into the end control port of the compensation valve, so that the valve port opening of the compensation valve becomes smaller and the flow rate becomes smaller. Therefore, the flow through the motor can be kept basically stable through hydraulic control compensation.

[0054] Specifically, the first compensation valve 8 and the second compensation valve 15 in this embodiment are both normally closed hydraulically controlled switch valves arranged before the motor reversing valve. Figure 1 As shown in the figure, the compensation valve is in its upper position, i.e. the on position, under normal conditions, and the pressure feedback is only used to control the valve opening size in the on position. Figure 1 The first compensation valve 8 and the second compensation valve 15 may both include:

[0055] A first hydraulically controlled end, the first hydraulically controlled end being a spring end; and

[0056] A second hydraulic control end, hydraulically connected to a valve forward oil port of a motor reversing valve;

[0057] The first hydraulic control end is hydraulically connected to the oil outlet of the shuttle valve to adjust the opening of the overflow valve port of the first compensation valve 8 .

[0058] See also Figure 1, the first compensation penalty 8 is arranged before the valve of the first motor reversing valve 9, and the hydraulic oil first passes through the first compensation valve 8 and then flows to the valve front oil port of the first motor reversing valve 9. The pressure oil flows into the valve front oil port of the first motor reversing valve 9 only when the first motor 11 is working. Therefore, under normal conditions, when the motor is not started, since the first hydraulic control end is a spring end, and the second hydraulic control end is connected to the valve front oil port of the first motor reversing valve 9 with extremely low pressure, the first compensation valve 8 is kept in the upper position, that is, the conduction position, and has a certain valve opening. When the pressure oil passes through the first compensation penalty 8 and the valve front oil port of the first motor reversing valve 9 in turn, and then drives the first motor 11 to work, the larger pressure at both ends of the motor is hydraulically drained to the first hydraulic control end through the first shuttle valve 10, and at the same time, the second hydraulic control end draws the oil pressure from the valve front oil port of the first motor reversing valve 9. At this time, the pressures hydraulically drained to the first hydraulic control end or drained to the second hydraulic control end basically offset each other, and the compensation valve still remains in the conduction position.

[0059] When the first motor 11 slips and idles, the load decreases, the pressure decreases, the flow rate through the motor increases, the motor speed increases, and the pressure fed back through the first shuttle valve 10 also decreases. Therefore, the valve opening of the first compensation valve 8 becomes smaller, limiting the flow of pressure oil to the first motor 11 until the motor speed decreases and the pressure increases, and the pressure feedback returns to the first hydraulic control end to restore the original valve opening.

[0060] In this embodiment, in order to achieve balanced flow of the motors on both sides of the equipment to keep the equipment moving in a straight line, the two motors connected in parallel are of the same model, that is, the specifications of the first motor 11 and the second motor 12 are the same. Similarly, the specifications of the first compensation valve 8 and the second compensation valve 15 are also the same, and the specifications of the first motor reversing valve 9 and the second motor reversing valve 14 are the same. In this way, it can be ensured that the flow is evenly distributed to the two motors to keep them moving in a straight line.

[0061] In this embodiment, the first motor reversing valve 9 and the second motor reversing valve 14 are both in the form of slide valves, so that the valve opening is continuously adjustable. Of course, the motor reversing valve used in this application is not limited to slide valves, and can also be other valve body structures with adjustable valve opening.

[0062] In order to simplify the hydraulic system of the aerial work platform, the oil in the travel motor circuit is taken from the middle position of the steering reversing valve 6. Figure 2 That is, when the steering reversing valve 6 is switched to the left or right position to drive the steering cylinder 7 to operate, the oil return port of the steering reversing valve 6 directly returns oil, as shown by the bold line in the figure. Only when the steering reversing valve 6 is switched to the middle position, the hydraulic oil with high pressure can flow to the motor circuit through the middle position of the reversing valve to drive the motor to operate. Figure 3 Indicated by the bold line in .

[0063] In particular, the travel motor circuit may also include:

[0064] An oil connection oil circuit L2, one end of which is connected to the oil return port of the steering reversing valve 6, and the other end of which is connected to the first motor oil circuit and the second motor oil circuit respectively; and

[0065] The motor oil return line L3 is connected from the oil return port of the first motor reversing valve 9 and the oil return port of the second motor reversing valve 14 to the hydraulic oil tank;

[0066] The oil intake connecting oil circuit L2 is provided with an oil intake one-way throttle valve 17, and the motor oil return oil circuit L3 is provided with an oil return one-way throttle valve 16.

[0067] Obviously, the oil return one-way throttle valve 16 and the oil extraction one-way throttle valve 17 can effectively control the fluid flow rate entering the motor circuit and the oil return flow rate.

[0068] exist Figure 1 As can be seen in the figure, the oil connection line L2 is hydraulically connected to the oil outlet of the return oil check valve 19, that is, hydraulically connected to the return oil port of the steering reversing valve 6. In this way, when the return oil bypass return oil line L1 described below is disconnected, the return oil of the steering cylinder circuit will enter the travel motor circuit through the oil connection line L2 and finally realize the return oil, but this return oil path is long and passes through many hydraulic components, and the return oil loss is large.

[0069] Therefore, returning to the steering cylinder circuit, this application also makes targeted improvements. Figure 1 As shown, the steering cylinder circuit also includes:

[0070] The steering valve oil return line is connected from the oil return port of the steering reversing valve 6 to the hydraulic oil tank and is provided with an oil return check valve 19 to prevent backflow; and

[0071] The bypass oil return circuit L1 bypasses the steering valve oil return circuit between the oil return port of the steering reversing valve 6 and the oil return check valve 19 to the hydraulic oil tank and is provided with a stop valve 18 for controlling the conduction or cutoff of the bypass oil return circuit L1.

[0072] The present application adds a bypass oil return circuit L1 to facilitate direct oil return and avoid oil return loss. In the prior art, the oil return from the steering oil circuit needs to pass through multiple one-way valves and motor reversing valves, etc., so the return oil pressure loss is large, resulting in a certain amount of energy waste. After the bypass oil return circuit L1 is provided, the stop valve 18 can be linked with the steering reversing valve 6. When the steering reversing valve 6 switches the valve position to drive the steering cylinder 7 to operate, the stop valve 18 can be energized and switched to the conduction position, thereby conducting the bypass oil return circuit L1. The return oil from the return port of the steering reversing valve 6 can return to the hydraulic oil tank almost unimpeded through the bypass oil return circuit L1, greatly reducing the return oil path and return oil resistance, and reducing hydraulic energy consumption. Among them, in order to simplify the hydraulic system, the stop valve 18, the compensation valve, etc. all use reversing valves with as few valve positions and as few ports as possible, and are designed for electrical or hydraulic control as needed.

[0073] See also Figure 1 , the steering cylinder circuit may also include:

[0074] Hydraulic pump 2;

[0075] The steering valve oil inlet circuit is connected from the oil outlet of the hydraulic pump 2 to the oil inlet of the steering reversing valve 6;

[0076] Wherein, a flow valve 5 is provided in the oil inlet circuit of the steering valve.

[0077] The flow valve 5 is used to adjust and control the total flow to the steering cylinder circuit and the travel motor circuit. A throttle port is provided inside the valve to stabilize the flow and pressure.

[0078] In addition, the hydraulic system may also include:

[0079] The main reversing valve 4 is arranged in the oil inlet circuit of the steering valve and is located between the oil outlet of the hydraulic pump 2 and the flow valve 5 .

[0080] The oil inlet of the steering valve is only connected to one of the working oil ports of the main reversing valve 4. Figure 1 The main reversing valve 4 shown is a two-position four-way valve, and also has a working oil port for supplying oil to other actuators or working accessories.

[0081] The following combination Figures 1 to 3 , specifically describing the walking and turning operation process of the aerial work platform. As mentioned above, the principle of the mainstream hydraulic system in the market is that the return oil of the steering oil circuit needs to pass through several one-way valves, one-way throttle valves, etc., which causes the hydraulic system to overcome the opening pressure of the one-way valve, and this part of the pressure is completely lost. Figure 1 , Figure 2As shown, the high-pressure oil of the present application flows out from the hydraulic pump 2 driven by the motor 1, passes through the main reversing valve 4, the flow valve 5, and the steering reversing valve 6 to reach the steering cylinder 7, and the return oil passes through the stop valve 18 and the filter 3 and returns to the oil tank. Among them, the direction of the oil in and out of the steering cylinder is switched by the three-position four-way steering reversing valve 6. After the return oil of the steering cylinder of the present application passes through the three-position four-way steering reversing valve 6, a two-position two-way stop valve 18 is connected in parallel with the return oil check valve 19. The return oil returns directly to the oil tank after passing through the stop valve 18, which reduces the pressure loss of the return oil during steering, thereby reducing energy consumption.

[0082] See also Figure 1 , Figure 3 After the pressure oil flows out of the hydraulic pump 2, it passes through the main reversing valve 4, the flow valve 5, the return oil one-way valve 19, and the oil extraction one-way throttle valve 17. The first route passes through the first compensation valve 8 and the three-position four-way first motor reversing valve 9 to reach the travel motor 11; the second route passes through the second compensation valve 15 and the three-position four-way second motor reversing valve 14 to reach the second motor 12. The return oil of the two routes passes through the return oil one-way throttle valve 16 and returns to the oil tank after the filter 3. Among them, the travel direction of the travel motor is switched by the three-position four-way first motor reversing valve 9 and the three-position four-way second motor reversing valve 14. Under the action of the first compensation valve 8 and the second compensation valve 15, the first motor 11 and the second motor 12 of the present application ensure that the flow of the two travel motors will not be affected by the load changes of the two motors, thereby improving the road adaptability and passing performance of the equipment.

[0083] The above-mentioned hydraulic system of the aerial work platform can be applied to various aerial work machines. In this embodiment, the aerial work platform used is a two-wheel drive scissor-type aerial work platform and the driving wheel axle is a rigid axle, and the first motor 11 and the second motor 12 are distributed on both sides of the driving wheel axle. In the prior art, when the two travel motors encounter uneven or slippery ground during driving, one side of the travel motor will slip and idle. Due to the rigid axle, it is easy to cause the equipment to not drive normally. The present application solves the problem of slipping and idling by adding matching compensation valves and shuttle valves.

[0084] Of course, it should be noted that the aerial work platform protected by this application is not limited to the two-wheel drive scissor type, but also covers other aerial work equipment. This application optimizes the main valve hydraulic principle and adds a two-position two-way solenoid valve in the bypass oil circuit between the return oil circuit of the steering reversing valve and the hydraulic oil tank. When the steering action is performed, the oil in the return oil circuit of the steering valve directly returns to the oil tank through the bypass oil circuit, reducing the return oil pressure loss during steering, thereby reducing energy consumption, and more in line with the energy-saving requirements of electrified equipment.

[0085] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0086] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0088] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. The hydraulic system of the aerial work platform is characterized by: The hydraulic system comprises: A steering cylinder circuit, comprising a steering reversing valve (6) for controlling a steering cylinder (7); and The travel motor circuit takes oil from the middle position of the steering reversing valve (6); The steering cylinder circuit further comprises a steering valve return oil circuit and a bypass return oil circuit (L1); the steering valve return oil circuit is connected from the return oil port of the steering reversing valve (6) to the hydraulic oil tank and is provided with a return oil check valve (19) for preventing backflow; the bypass return oil circuit (L1) bypasses the steering valve return oil circuit between the return oil port of the steering reversing valve (6) and the return oil check valve (19) to the hydraulic oil tank and is provided with a stop valve (18) for controlling the conduction or cutoff of the bypass return oil circuit (L1).

2. The hydraulic system of the aerial work platform according to claim 1, characterized in that: The steering cylinder circuit also includes: Hydraulic pump (2); A steering valve oil inlet circuit, connected from the oil outlet of the hydraulic pump (2) to the oil inlet of the steering reversing valve (6); Wherein, a flow valve (5) is provided in the oil inlet circuit of the steering valve.

3. The hydraulic system of the aerial work platform according to claim 2, characterized in that: The hydraulic system comprises: A main reversing valve (4) is arranged in the oil inlet circuit of the steering valve and is located between the oil outlet of the hydraulic pump (2) and the flow valve (5).

4. The hydraulic system for an aerial work platform according to any one of claims 1 to 3, characterized in that: The travel motor circuit comprises a first motor oil circuit and a second motor oil circuit arranged in parallel, the first motor oil circuit comprising a first motor reversing valve (9) for controlling a first motor (11) and a first compensation valve (8) for maintaining a stable flow rate through the first motor reversing valve (9), and the second motor oil circuit comprising a second motor reversing valve (14) for controlling a second motor (12) and a second compensation valve (15) for maintaining a stable flow rate through the second motor reversing valve (14).

5. The hydraulic system for an aerial work platform according to claim 4, characterized in that: The travel motor circuit comprises: An oil connection oil circuit (L2) having one end connected to the oil return port of the steering reversing valve (6) and the other end connected to the first motor oil circuit and the second motor oil circuit respectively; and A motor oil return circuit (L3) connected from an oil return port of the first motor reversing valve (9) and an oil return port of the second motor reversing valve (14) to a hydraulic oil tank; The oil extraction connecting oil circuit (L2) is provided with an oil extraction one-way throttle valve (17), and the motor oil return oil circuit (L3) is provided with an oil return one-way throttle valve (16).

6. The hydraulic system for an aerial work platform according to claim 5, characterized in that: The oil extraction connecting oil circuit (L2) is hydraulically connected to the oil outlet of the oil return one-way valve (19).

7. The hydraulic system for an aerial work platform according to claim 4, characterized in that: The first motor circuit comprises a first shuttle valve (10), wherein two comparison oil ports of the first shuttle valve (10) are respectively hydraulically connected to the oil ports at both ends of the first motor (11), and the oil outlet of the shuttle valve is connected to the first hydraulic control end of the first compensation valve (8); the second motor circuit comprises a second shuttle valve (13), wherein two comparison oil ports of the second shuttle valve (13) are respectively hydraulically connected to the oil ports at both ends of the second motor (12), and the oil outlet of the shuttle valve is connected to the first hydraulic control end of the second compensation valve (15).

8. The hydraulic system for an aerial work platform according to claim 7, characterized in that: The first compensation valve (8) and the second compensation valve (15) are both normally closed hydraulically controlled switch valves arranged in front of the motor reversing valve and include: The first hydraulic control end is a spring end; and a second hydraulic control end, hydraulically connected to a valve forward oil port of the motor reversing valve; Wherein, the first hydraulic control end is hydraulically connected to the oil outlet of the shuttle valve to adjust the opening of the overflow valve port of the first compensation valve (8).

9. The hydraulic system for an aerial work platform according to claim 4, characterized in that: The first motor reversing valve (9) and the second motor reversing valve (14) are slide valves.

10. An aerial work platform, characterized in that: The aerial work platform comprises a hydraulic system for an aerial work platform according to any one of claims 1 to 9.

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