Hydraulic walking system of wheel-track composite transport vehicle, control method and transport vehicle

Abstract

The invention relates to the technical field of hydraulic pressure, and discloses a hydraulic walking system of a wheel-track composite transport vehicle, a control method and a transport vehicle. The hydraulic walking system of the wheel-track combined transport vehicle comprises at least two closed walking driving subsystems, wherein each closed walking driving subsystem comprises a closed pump module, a walking driving module and a switching valve module; the walking driving module comprises a wheel driving unit and a track driving unit; the switching valve module comprises a first oil way unit and a second oil way unit which are connected with the closed pump module, and the first oil way unit and the second oil way unit are both connected with the wheel driving unit and the track driving unit. According to the hydraulic walking system of the wheel-track combined transport vehicle, a closed system is adopted, the system pressure is high, the flow is large, the application range is wide, and therefore the carrying efficiency is higher. And hydraulic components are reduced, the occupied space is reduced, and the reliability is higher.

Description

Technical Field

[0001] The present application belongs to the field of hydraulic technology, and specifically relates to a hydraulic walking system, a control method and a transport vehicle for a wheel-track composite transport vehicle. Background Art

[0002] At present, the power grid construction environment is faced with various terrains such as mountainous areas, paddy fields, and river beaches. When constructing high-voltage power transmission towers in these complex terrains, the produced tower materials are first sent to a place with convenient transportation and where large trucks can park, and then transported to the tower material construction and installation site by manpower or small vehicles. When encountering mountains, paddy fields, swamps or other harsh terrains and tower materials are large and heavy, it is very difficult to transport them by manpower and small equipment, and it takes a long time and is dangerous.

[0003] At present, transport vehicles are mainly divided into wheeled and crawler-type. These two chassis have their own advantages and characteristics. The wheeled chassis has a fast driving speed, easy transfer, and does not require special transfer tools. The crawler chassis has a wide range of applicability and can operate in complex and harsh terrains, but the driving speed is slow and requires a special flatbed truck for transfer. For this reason, the prior art provides a wheel-crawler composite transport vehicle, the travel hydraulic system of which adopts a double-open variable pump and logic control through multiple sliding valves to realize wheel-crawler oil circuit switching. The existing wheel-crawler composite transport vehicle travel hydraulic system has the following problems:

[0004] (1) The hydraulic components of the open system take up a lot of space;

[0005] (2) Open system: The entire system pressure is low and cannot meet the driving requirements under high load conditions. Summary of the invention

[0006] The purpose of the present application is to provide a hydraulic travel system, a control method and a transport vehicle for a wheel-track composite transport vehicle, so as to solve the problem in the prior art that the open system occupies a large space and the system pressure is low and cannot meet the driving requirements under heavy load conditions.

[0007] In order to achieve the above-mentioned object, the first aspect of the present application provides a hydraulic travel system of a wheel-track composite transport vehicle, comprising at least two closed travel drive subsystems, wherein the closed travel drive subsystems include:

[0008] Closed pump module;

[0009] A travel drive module, including a wheel drive unit and a track drive unit; and

[0010] A switching valve module, comprising a first oil circuit unit and a second oil circuit unit connected to the closed pump module, wherein the first oil circuit unit and the second oil circuit unit are both connected to the wheel drive unit and the track drive unit;

[0011] Among them, when executing forward drive, the switching valve module is used to control the first oil circuit unit to selectively inject oil into the forward oil port of the wheel drive unit or the track drive unit; when executing reverse drive, the switching valve module is used to control the second oil circuit unit to selectively inject oil into the reverse oil port of the wheel drive unit or the track drive unit.

[0012] As a further improvement of the above technical solution:

[0013] In some embodiments, the switching valve module includes:

[0014] A travel switching valve, comprising the first oil circuit unit and the second oil circuit unit, wherein a first shuttle valve is arranged between the first oil circuit unit and the second oil circuit unit;

[0015] A reversing valve, connecting the oil outlet of the first shuttle valve and the valve port for controlling switching on the travel switching valve;

[0016] Among them, when executing forward drive, the reversing valve is used to control the first oil circuit unit to selectively inject oil into the forward oil port of the wheel drive unit or the track drive unit; when executing reverse drive, the reversing valve is used to control the second oil circuit unit to selectively inject oil into the reverse oil port of the wheel drive unit or the track drive unit.

[0017] In some embodiments, the travel switching valve includes a first cartridge valve, a second cartridge valve, a third cartridge valve, and a fourth cartridge valve;

[0018] The oil inlets of the first cartridge valve and the second cartridge valve are both connected to the first pump oil port in the closed pump module to form the first oil circuit unit, the oil outlet of the first cartridge valve is connected to the forward oil port of the wheel drive unit, and the oil outlet of the second cartridge valve is connected to the forward oil port of the track drive unit;

[0019] The oil inlets of the third cartridge valve and the fourth cartridge valve are both connected to the second pump oil port in the closed pump module to form the second oil circuit unit, the oil outlet of the third cartridge valve is connected to the reversing oil port of the track drive unit, and the oil outlet of the fourth cartridge valve is connected to the reversing oil port of the wheel drive unit;

[0020] When performing forward driving or backward driving, the reversing valve is used to control two of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve to be selectively turned on.

[0021] In some embodiments, the closed travel drive subsystem is provided with two, the switching valve modules in the two closed travel drive subsystems share one reversing valve, and the travel switching valves in the two closed travel drive subsystems share a valve body;

[0022] Wherein, a second shuttle valve is further provided in the valve body, the first shuttle valves in the valve body are connected to the second shuttle valves, and the ports of the second shuttle valves are connected to the reversing valve.

[0023] In some embodiments, the reversing valve is a two-position four-way electromagnetic reversing valve.

[0024] In some embodiments, the hydraulic walking system of the wheel-track composite transport vehicle also includes a speed switching valve, which is connected to the variable ports of the wheel drive unit and the track drive unit. The speed switching valve is also connected to the oil tank and the closed pump module. The speed switching valve controls the speed of the wheel drive unit or the track drive unit by controlling the pressure of the hydraulic oil in the variable port.

[0025] In some embodiments, two closed travel drive subsystems are provided, and the closed pump modules in the two closed travel drive subsystems are connected in series and driven by the same power input module.

[0026] In some embodiments, the power input module includes an engine and / or a motor.

[0027] In order to achieve the above-mentioned purpose, the second aspect of the present application provides a control method for the hydraulic walking system of a wheel-track composite transport vehicle, which is applied to the hydraulic walking system of the wheel-track composite transport vehicle provided according to the first aspect above, and the control method includes wheel forward control, wheel backward control, track forward control and track backward control;

[0028] When executing the wheel forward control, the closed pump module is controlled to supply oil to the first oil circuit unit, and then the switching valve module controls the first oil circuit unit to inject oil to the forward oil port of the wheel drive unit to achieve forward drive;

[0029] When executing the wheel backward control, the closed pump module is controlled to supply oil to the second oil circuit unit, and then the switching valve module controls the second oil circuit unit to inject oil to the reverse oil port of the wheel drive unit to achieve backward drive;

[0030] When the crawler track forward control is executed, the closed pump module is controlled to supply oil to the first oil circuit unit, and then the switching valve module controls the first oil circuit unit to inject oil to the forward oil port of the crawler track drive unit to achieve forward drive;

[0031] When executing the track backward control, the closed pump module is controlled to supply oil to the second oil circuit unit, and then the switching valve module controls the second oil circuit unit to inject oil to the corresponding reversing oil port of the track drive unit to achieve backward drive.

[0032] In order to achieve the above-mentioned purpose, the third aspect of the present application provides a transport vehicle, including a wheel-track composite chassis and a hydraulic walking system of the wheel-track composite transport vehicle provided according to the above-mentioned first aspect.

[0033] Compared with the prior art, the hydraulic travel system, control method and transport vehicle of the wheel-track composite transport vehicle provided by the present application have at least the following beneficial effects:

[0034] The hydraulic travel system of the wheel-track composite transport vehicle provided by the present application provides driving hydraulic oil through a closed pump module. When forward driving is required, the switching valve module is controlled to selectively inject oil into the forward oil port of the wheel drive unit or the track drive unit to achieve forward driving; when backward driving is required, the switching valve module is controlled to selectively inject oil into the reverse oil port of the wheel drive unit or the track drive unit to achieve backward driving. Compared with the prior art, the hydraulic travel system of the wheel-track composite transport vehicle provided by the present application adopts a closed system with high system pressure, large flow rate, and wide application range, so as to achieve higher transportation efficiency. Furthermore, the hydraulic components are reduced, the structure is simplified, the layout is more compact, the space occupancy is reduced, and the reliability is higher.

[0035] 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

[0036] 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:

[0037] Figure 1 A schematic diagram of the oil circuit of a hydraulic travel system of a wheel-track composite transport vehicle provided in Example 1 of the present application;

[0038] Figure 2 for Figure 1 A schematic diagram of the partial structure of a switching valve module in the hydraulic walking system of a wheel-track composite transport vehicle shown in FIG.

[0039] Figure 3 A schematic diagram of the oil circuit of a hydraulic walking system of a wheel-track composite transport vehicle provided in Example 2 of the present application;

[0040] Figure 4 for Figure 3 The simplified partial structural diagram of the hydraulic travel system of the wheel-track composite transport vehicle shown in FIG.

[0041] Figure 5 for Figure 3 A schematic diagram of the partial structure of a switching valve module in the hydraulic walking system of a wheel-track composite transport vehicle shown in FIG.

[0042] Figure 6 A schematic diagram of the three-dimensional structure of a travel switching valve provided in Example 2 of the present application.

[0043] Description of Reference Numerals

[0044] 100. Fuel tank;

[0045] 200, closed pump module; 200a, first closed pump module; VA1, first pump oil port; VB1, second pump oil port; 200b, second closed pump module; VA2, third pump oil port; VB2, fourth pump oil port; 210, control valve; 210a, first control valve; 210b, second control valve;

[0046] 300, power output module;

[0047] 400, travel drive module; 410, wheel drive unit; 410a, first wheel drive unit; 410b, second wheel drive unit; 420, track drive unit; 420a, first track drive unit; 420b, second track drive unit;

[0048] 500, speed switching valve;

[0049] 600, switching valve module; 601, first oil circuit unit; 602, second oil circuit unit; 603, third oil circuit unit; 604, fourth oil circuit unit; 605, first control oil circuit; 606, second control oil circuit; 610, travel switching valve; 611, valve body; 612a, first cartridge valve; 612b, second cartridge valve; 612c, third cartridge valve; 612d, fourth cartridge valve; 612e, fifth cartridge valve; 612f, sixth cartridge valve; 612g, seventh cartridge valve; 612h, eighth cartridge valve; 612i, first shuttle valve; 612j, second shuttle valve; 620, reversing valve;

[0050] 700. Oil suction filter. DETAILED DESCRIPTION

[0051] 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.

[0052] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0053] Embodiment 1

[0054] See also Figure 1 and Figure 2 This embodiment provides a hydraulic walking system for a wheel-track composite transport vehicle, which is applied to the transport vehicle to control the forward or backward movement of the wheels or tracks.

[0055] In this embodiment, the hydraulic travel system of the wheel-track composite transport vehicle includes at least two closed travel drive subsystems. In this embodiment, two closed travel drive subsystems are used as examples for illustration, but other numbers are also possible. The structures of the two closed travel drive subsystems are the same, and the following describes one of the two closed travel drive subsystems.

[0056] The closed travel drive subsystem includes a closed pump module 200, a travel drive module 400 and a switching valve module 600. The closed pump module 200 includes two pump oil ports, which are defined as the first pump oil port VA1 and the second pump oil port VB1 for distinguishing descriptions. When the first pump oil port VA1 is discharging oil, the second pump oil port VB1 is used to return oil. When the second pump oil port VB1 is discharging oil, the first pump oil port VA1 returns oil.

[0057] Furthermore, the closed pump module 200 is also configured with a control valve 210, and the oil output of the first pump oil port VA1 or the second pump oil port VB1 can be selectively controlled by switching the controlled valve core.

[0058] The travel drive module 400 includes a wheel drive unit 410 and a track drive unit 420. The wheel drive unit 410 includes a wheel travel motor for providing driving force, and the track drive unit 420 includes a track travel motor for providing driving force. In this embodiment, the wheel drive unit 410 and the track drive unit 420 both have a forward oil filling port and a reverse oil filling port, and define that when the wheel travel motor and the track travel motor rotate forward, they correspond to driving forward, and when they rotate reversely, they correspond to driving backward.

[0059] The switching valve module 600 includes a first oil circuit unit 601 and a second oil circuit unit 602 connected to the closed pump module 200, and the first oil circuit unit 601 and the second oil circuit unit 602 are both connected to the wheel drive unit 410 and the track drive unit 420. Specifically, the first oil circuit unit 601 is connected to the forward oil injection ports of the wheel drive unit 410 and the track drive unit 420, and the second oil circuit unit 602 is connected to the reverse oil injection ports of the wheel drive unit 410 and the track drive unit 420.

[0060] In this way, it can be understood that when executing forward drive, the switching valve module 600 is used to control the first oil circuit unit 601 to selectively inject oil into the forward oil port of the wheel drive unit 410 or the track drive unit 420 to achieve forward drive; when executing reverse drive, the switching valve module 600 is used to control the second oil circuit unit 602 to selectively inject oil into the reverse oil port of the wheel drive unit 410 or the track drive unit 420 to achieve reverse drive.

[0061] Compared with the prior art, the hydraulic travel system of the wheel-track composite transport vehicle provided in this embodiment adopts a closed system, which has high system pressure, large flow, and a wide range of applications, thereby having higher transportation efficiency. Furthermore, the number of hydraulic components is reduced, the structure is simplified, the layout is more compact, the space occupancy is reduced, and the reliability is higher.

[0062] In this embodiment, the switching valve module 600 includes a travel switching valve 610 and a reversing valve 620. The reversing valve 620 is used to control the travel switching valve 610 to select oil supply to the wheel drive unit 410 or the track drive unit 420.

[0063] The travel switching valve 610 includes a first oil circuit unit 601 and a second oil circuit unit 602 , and a first shuttle valve 612i is provided between the first oil circuit unit 601 and the second oil circuit unit 602 ; the reversing valve 620 connects the oil outlet of the first shuttle valve 612i and the valve port on the travel switching valve 610 for controlling switching.

[0064] In this way, when performing forward drive, the reversing valve 620 is used to control the first oil circuit unit 601 to selectively inject oil into the forward oil port of the wheel drive unit 410 or the track drive unit 420; when performing reverse drive, the reversing valve 620 is used to control the second oil circuit unit 602 to selectively inject oil into the reverse oil port of the wheel drive unit 410 or the track drive unit 420.

[0065] See also Figure 1 and Figure 2Specifically, the travel switching valve 610 further includes a first cartridge valve 612a, a second cartridge valve 612b, a third cartridge valve 612c and a fourth cartridge valve 612d. The oil inlets of the first cartridge valve 612a and the second cartridge valve 612b are connected to the first pump oil port VA1 in the closed pump module 200 to form a first oil circuit unit 601. The oil outlet of the first cartridge valve 612a is connected to the forward oil port of the wheel drive unit 410, and the oil outlet of the second cartridge valve 612b is connected to the forward oil port of the track drive unit 420. The oil inlets of the third cartridge valve 612c and the fourth cartridge valve 612d are connected to the second pump oil port VB1 in the closed pump module 200 to form a second oil circuit unit 602. The oil outlet of the third cartridge valve 612c is connected to the reverse oil port of the track drive unit 420, and the oil outlet of the fourth cartridge valve 612d is connected to the reverse oil port of the wheel drive unit 410. Thus, when performing forward drive or reverse drive, the reversing valve 620 is used to control two of the first cartridge valve 612a, the second cartridge valve 612b, the third cartridge valve 612c and the fourth cartridge valve 612d to be selectively turned on, that is, one of them is used for oil intake and the other is used for oil return.

[0066] Furthermore, the reversing valve 620 is selected as a two-position four-way electromagnetic reversing valve 620. In this way, the reversing valve 620 can be switched by electromagnetic control, thereby facilitating remote control.

[0067] The hydraulic travel system of the wheel-track composite transport vehicle also includes an oil tank 100. The closed pump module 200 is connected to the oil tank 100 through an oil pipe, and an oil suction filter 700 is also provided at the oil inlet end of the oil pipe to replenish the hydraulic oil.

[0068] Please also read Figure 2 In this embodiment, the reversing valve 620 has four reversing oil ports, namely the first reversing oil port T1, the second reversing oil port T2, the third reversing oil port T3 and the fourth reversing oil port T4. Among them, the first reversing oil port T1 returns to the oil tank 100, the second reversing oil port T2 is connected to the control end of the second cartridge valve 612b and the third cartridge valve 612c in the travel switching valve 610, the third reversing oil port T3 is connected to the outlet of the first shuttle valve 612i in the travel switching valve 610, and the fourth reversing oil port T4 is connected to the control end of the first cartridge valve 612a and the fourth cartridge valve 612d. The reversing valve 620 can selectively connect the third reversing oil port T3 with the second reversing oil port T2 and the fourth reversing oil port T4 by switching the valve core. Therefore, the hydraulic oil from the first shuttle valve 612i can be used to control the on / off of the first cartridge valve 612a and the fourth cartridge valve 612d or the on / off of the second cartridge valve 612b and the third cartridge valve 612c.

[0069] In this embodiment, the travel switching valve 610 further includes a valve body 611, and the first cartridge valve 612a, the second cartridge valve 612b, the third cartridge valve 612c, the fourth cartridge valve 612d, and the first shuttle valve 612i are all integrated on the valve body 611. The valve body 611 is also provided with a plurality of valve ports for connecting pipelines (for a detailed description of the valve ports, see Embodiment 2).

[0070] The hydraulic travel system of the wheel-track composite transport vehicle also includes a speed switching valve 500, which is connected to the variable ports of the wheel drive unit 410 and the track drive unit 420. The speed switching valve 500 is also connected to the oil tank 100 and the closed pump module 200. The speed switching valve 500 controls the speed of the wheel drive unit 410 or the track drive unit 420 by controlling the pressure of the hydraulic oil in the variable port.

[0071] It is understandable that when the closed pump module 200 injects hydraulic oil into the variable port through the speed switching valve 500, the oil pressure of the variable port increases, thereby increasing the displacement of the motor (wheel travel motor or crawler travel motor), reducing the motor speed and increasing the torque. When the speed switching valve 500 switches to return oil to the oil tank 100, the variable port releases pressure to the oil tank 100, and the oil pressure of the variable port decreases, thereby reducing the displacement of the motor and increasing the speed.

[0072] Optionally, the speed switching valve 500 may be a two-position four-way electromagnetic reversing valve 620 or a two-position three-way electromagnetic reversing valve 620 .

[0073] Optionally, two closed travel drive subsystems may share one speed switching valve 500 .

[0074] In this embodiment, the closed pump modules 200 in the two closed travel drive subsystems are connected in series and driven by the same power input module, thereby ensuring the synchronization of the movements, saving costs, and reducing the occupation of installation space.

[0075] Optionally, the power input module includes an engine or a motor. In some embodiments, the power input module includes an engine and a motor, thereby realizing hybrid drive.

[0076] See also Figure 1 and Figure 2 Furthermore, this embodiment also provides a method for controlling the hydraulic walking system of a wheel-track composite transport vehicle, and the control method includes wheel forward control, wheel backward control, track forward control and track backward control.

[0077] Take one of the closed travel drive subsystems as an example to illustrate:

[0078] First, when the electromagnet of the control valve 210 in the closed pump module 200 is not energized (both the left position a and the right position b are not energized), no hydraulic oil flows out of the pump body in the closed pump module 200. When the electromagnet on the right position b of the control valve 210 is energized, Figure 1 As shown, high-pressure hydraulic oil flows from the first pump oil port VA1 of the closed pump module 200 into the first oil circuit unit 601 of the travel switching valve 610. Conversely, when the electromagnet on the left position a of the control valve 210 is energized, high-pressure hydraulic oil flows from the second pump oil port VB1 on the closed pump module 200 into the second oil circuit unit 602 of the travel switching valve 610.

[0079] When executing wheel forward control, the closed pump module 200 is controlled to supply oil to the first oil circuit unit 601, and then the switching valve module 600 controls the first oil circuit unit 601 to supply oil to the positive rotation oil port R of the wheel drive unit 410 to achieve forward drive.

[0080] When executing wheel reverse control, the closed pump module 200 is controlled to supply oil to the second oil circuit unit 602, and then the switching valve module 600 controls the second oil circuit unit 602 to supply oil to the reverse oil filling port L of the wheel driving unit 410 to realize reverse driving.

[0081] Specifically, in the wheel travel mode, the electromagnet of the reversing valve 620 is not energized in the default state, and the valve core of the reversing valve 620 remains in the right position for operation. When the electromagnet on the right position b of the control valve 210 is energized, the high-pressure hydraulic oil flowing out of the first pump oil port VA1 enters the first oil circuit unit 601 of the travel switching valve 610, wherein a part of the pressure oil of the first oil circuit unit 601 passes through the internal oil channel of the valve body 611 and passes through the first shuttle valve 612i and then enters the third reversing oil port T3 of the reversing valve 620, and then flows into the valve body 611 from the second reversing oil port T2 of the reversing valve 620, and finally acts on the control ends of the second cartridge valve 612b and the third cartridge valve 612c to adjust the second cartridge valve 612b and the third cartridge valve 612c. 2c's A and B ports are cut off; at the same time, the pressure oil at the control end of the first cartridge valve 612a and the fourth cartridge valve 612d enters the fourth reversing oil port T4 of the reversing valve 620 through the internal flow channel of the valve body 611, and then flows out from the first reversing oil port T1 back to the oil tank 100, so that the A and B ports of the first cartridge valve 612a and the fourth cartridge valve 612d are connected, so that the pressure oil in the first oil circuit unit 601 can flow out through the first cartridge valve 612a and act on the forward oil filling port R of the wheel drive unit 410, thereby driving the wheel travel motor to rotate forward and the whole vehicle moves forward. The reverse oil filling port L of the wheel drive unit 410 returns oil, is connected back to the valve body 611 through a pipeline, and flows back to the closed pump module 200 through the fourth cartridge valve 612d. When the electromagnet on the left position a of the control valve 210 is energized, the high-pressure hydraulic oil flowing out of the second pump oil port VB1 enters the second oil circuit unit 602 of the travel switching valve 610, and then acts on the reverse oil filling port L of the wheel drive unit 410 through the fourth cartridge valve 612d, driving the wheel travel motor to rotate in the opposite direction, and the whole vehicle moves backward.

[0082] When the crawler track forward control is executed, the closed pump module 200 is controlled to supply oil to the first oil circuit unit 601, and then the switching valve module 600 controls the first oil circuit unit 601 to supply oil to the forward rotation oil injection port P1 of the crawler track drive unit 420 to realize forward drive;

[0083] When executing the track backward control, the closed pump module 200 is controlled to supply oil to the second oil circuit unit 602, and then the switching valve module 600 controls the second oil circuit unit 602 to supply oil to the corresponding reverse oil filling port P2 of the track drive unit 420 to achieve backward drive.

[0084] Specifically, in the crawler walking mode, when the electromagnet of the reversing valve 620 is energized and maintained, the valve core switches to the left position to work. When the electromagnet on the right position b of the control valve 210 is energized, the high-pressure hydraulic oil flowing out of the first pump oil port VA1 enters the first oil circuit unit 601 of the walking switching valve 610, wherein a part of the pressure oil in the first oil circuit unit 601 passes through the internal oil channel of the valve body 611 and the first shuttle valve 612i to enter the third reversing oil port T3 of the reversing valve 620, and then flows into the valve body 611 from the fourth reversing oil port T4 of the reversing valve 620, and finally acts on the control ends of the first cartridge valve 612a and the fourth cartridge valve 612d to adjust the control ends of the first cartridge valve 612a and the fourth cartridge valve 612d. The A and B ports of the control end are cut off; at the same time, the pressure oil of the control end of the second cartridge valve 612b and the third cartridge valve 612c enters the second reversing oil port T2 of the reversing valve 620 through the internal flow channel of the valve body 611, and then flows out from the first reversing oil port T1 to return to the oil tank 100, so that the A and B ports of the second cartridge valve 612b and the third cartridge valve 612c are connected, so that the pressure oil in the first oil circuit unit 601 can directly act on the forward oil filling port P1 of the crawler drive unit 420 through the second cartridge valve 612b, thereby driving the crawler travel motor to rotate forward and the whole vehicle moves forward. The return oil of the reverse oil filling port P2 of the crawler drive unit 420 is connected back to the valve body 611 through the pipeline, and then enters the closed pump module 200 through the third cartridge valve 612c. Similarly, when the electromagnet on the left position a of the control valve 210 is energized, the backward function can be realized.

[0085] It should be noted that in the prior art, the hydraulic system of the wheel-track composite transport vehicle adopts a double-open variable pump and logic control of multiple sliding valves to realize wheel-track oil circuit switching, which has the following disadvantages: 1. In the open system, the hydraulic components occupy a large space; 2. In the open system, the pressure of the entire system is low, which cannot meet the driving requirements under large load conditions; 3. The wheel-track oil circuit switching is realized by logic control of multiple multi-way valves. Due to the size limitation of the multi-way valve, the large flow and high pressure requirements of the whole vehicle cannot be met; 4. The multi-way switching valve is a sliding valve structure with high precision requirements. It is easy to wear after long-term use and there is a risk of leakage. The valve core is easy to get stuck when it encounters contamination; 5. The multi-way valve needs to match valve cores of different specifications at different flow rates. The larger the flow demand, the larger the size of the valve. At the same time, when the size of the reversing valve 620 is large, the corresponding overflow valve is also large, the volume of the entire hydraulic component will also increase, the pipeline connection is complicated, and the price is high.

[0086] Compared with the prior art, the hydraulic travel system of the wheel-track composite transport vehicle provided in this embodiment has the following advantages:

[0087] (1) A hydraulic travel closed system was designed, which has high pressure, large flow, wide application range, high carrying efficiency, can be remotely controlled through electrical control, and has high safety.

[0088] (2) A dual-pump four-motor switching hydraulic system control is designed, which realizes the oil circuit switching of the travel switching valve 610 through the reversing valve 620, and uses a small flow to control a large flow. The switching logic is reliable and has fewer hydraulic components.

[0089] (3) At the same time, a travel switching valve 610 is designed, which has compact size, small installation space requirement, high degree of integration, and replaces the traditional slide valve with a cartridge valve. It can achieve zero leakage of pressure oil, strong anti-pollution ability, valve core is not easy to get stuck, stable performance, high reliability, and cheaper than the traditional slide valve.

[0090] Embodiment 2

[0091] See also Figure 3 and Figure 4 This embodiment provides a hydraulic walking system for a wheel-track composite transport vehicle, which can be applied to a transport vehicle with a wheel-track composite structure. This embodiment is an improvement made on the technical basis of the above embodiment 1. Compared with the above embodiment 1, the difference is that:

[0092] In this embodiment, in order to distinguish the two closed pump modules 200, the two closed pump modules 200 are defined as the first closed pump module 200a and the second closed pump module 200b. For distinguishing description, the two pump oil ports of the first closed pump module 200a are defined as the first pump oil port VA1, the second pump oil port VB1 and the first control valve 210a, and the two pump oil ports of the second closed pump module 200b are defined as the third pump oil port VA2, the fourth pump oil port VB2 and the second control valve 210b. Among them, the functions of the first control valve 210a and the second control valve 210b are the same, and the specifics can be referred to the description of the control valve 210 and the control module in the above embodiment 1, which will not be repeated in this embodiment.

[0093] In this embodiment, there are two closed travel drive subsystems, and there are two wheel drive units 410 and two track drive units 420 in the two closed travel drive subsystems. The two wheel drive units 410 are defined as a first wheel drive unit 410a and a second wheel drive unit 410b, the first wheel drive unit 410a corresponds to the first closed pump module 200a, and the second wheel drive unit 410b corresponds to the second closed pump module 200b; the two track drive units 420 are defined as a first track drive unit 420a and a second track drive unit 420b. The first track drive unit 420a and the first wheel drive unit 410a correspond to the first closed pump module 200a, and the second track drive unit 420b and the second wheel drive unit 410b correspond to the second closed pump module 200b.

[0094] See also Figure 3 , Figure 4 and Figure 5 In this embodiment, the switching valve modules 600 in the two closed walking driving subsystems share a reversing valve 620 , and the walking switching valves 610 in the two closed walking driving subsystems share a valve body 611 .

[0095] Please also read Figure 6 , wherein the number of cartridge valves in the two closed travel drive subsystems is 8, and the 8 cartridge valves are all integrated on a valve body 611. In order to distinguish the description, they are respectively defined as the first cartridge valve 612a, the second cartridge valve 612b, the third cartridge valve 612c, the fourth cartridge valve 612d, the fifth cartridge valve 612e, the sixth cartridge valve 612f, the seventh cartridge valve 612g, and the eighth cartridge valve 612h. The first cartridge valve 612a, the second cartridge valve 612b, the third cartridge valve 612c, and the fourth cartridge valve 612d belong to the first closed travel drive subsystem; the fifth cartridge valve 612e, the sixth cartridge valve 612f, the seventh cartridge valve 612g, and the eighth cartridge valve 612h belong to the second closed travel drive subsystem.

[0096] See also Figure 4 , Figure 5 and Figure 6 In order to more clearly describe the structure of the travel switching valve 610, multiple valve ports are defined as the first valve port VA, the second valve port VB, the third valve port VAA, the fourth valve port VBB, the fifth valve port V1A, the sixth valve port V2A, the seventh valve port V1B, the eighth valve port V2B, the ninth valve port V1AA, the tenth valve port V2AA, the eleventh valve port V1BB, the twelfth valve port V2BB, the thirteenth valve port M, the fourteenth valve port M1, the fifteenth valve port M2, the sixteenth valve port M3 and the seventeenth valve port M4.

[0097] Specifically, the oil inlets of the first cartridge valve 612a and the second cartridge valve 612b are connected to the first pump oil port VA1 through the first valve port VA to form the first oil circuit unit 601. The oil outlet of the first cartridge valve 612a is connected to the normal rotation oil injection port R of the first wheel drive unit 410a through the fifth valve port V1A. The oil outlet of the second cartridge valve 612b is connected to the normal rotation oil injection port P1 of the first crawler drive unit 420a through the sixth valve port V2A.

[0098] The oil inlets of the third cartridge valve 612c and the fourth cartridge valve 612d are connected to the second pump oil port VB1 through the second valve port VB to form the second oil circuit unit 602. The oil outlet of the third cartridge valve 612c is connected to the reverse oil injection port P2 of the first crawler drive unit 420a through the eighth valve port V2B, and the oil outlet of the fourth cartridge valve 612d is connected to the reverse oil injection port L of the first wheel drive unit 410a through the seventh valve port V1B.

[0099] The oil inlets of the fifth cartridge valve 612e and the sixth cartridge valve 612f are connected to the third pump oil port VA2 through the third valve port VAA to form the third oil circuit unit 603. The oil outlet of the fifth cartridge valve 612e is connected to the normal rotation oil injection port R of the first wheel drive unit 410a through the ninth valve port V1AA, and the oil outlet of the sixth cartridge valve 612f is connected to the normal rotation oil injection port P1 of the first crawler drive unit 420a through the tenth valve port V2AA.

[0100] The oil inlets of the seventh cartridge valve 612g and the eighth cartridge valve 612h are connected to the fourth pump oil port VB2 through the fourth valve port VBB to form the fourth oil circuit unit 604. The oil outlet of the seventh cartridge valve 612g is connected to the reverse oil injection port P2 of the first crawler drive unit 420a through the twelfth valve port V2BB, and the oil outlet of the eighth cartridge valve 612h is connected to the reverse oil injection port L of the first wheel drive unit 410a through the eleventh valve port V1BB.

[0101] Furthermore, a second shuttle valve 612j is further provided in the valve body 611, and the second shuttle valve 612j is connected to the two first shuttle valves 612i in the valve body 611, and then connected to the reversing valve 620. In this way, the hydraulic oil from the first shuttle valve 612i first enters the second shuttle valve 612j, and then the second shuttle valve 612j is connected to the third reversing oil port T3 of the reversing valve 620 through the thirteenth valve port M on the valve body 611.

[0102] The valve body 611 is also provided with a first control oil circuit 605 and a second control oil circuit 606. Among them, the control ends of the first cartridge valve 612a, the fourth cartridge valve 612d, the fifth cartridge valve 612e and the eighth cartridge valve 612h are connected to the second reversing oil port T2 of the reversing valve 620 through the seventeenth valve port M4 by the first control oil circuit 605; the second cartridge valve 612b, the third cartridge valve 612c, the sixth cartridge valve 612f and the seventh cartridge valve 612g are connected to the fourth reversing oil port T4 of the reversing valve 620 through the sixteenth valve port M3 by the second control oil circuit 606. The first reversing oil port T1 of the reversing valve 620 returns to the oil tank 100.

[0103] The fourteenth valve port M1 and the fifteenth valve port M2 on the travel switching valve 610 can be used as reserved ports. In this embodiment, the fourteenth valve port M1 on the travel switching valve 610 is connected to the outlet of the first shuttle valve 612i, and the fifteenth valve port M2 is connected to the outlet of the second shuttle valve 612j. The fourteenth valve port M1 and the fifteenth valve port M2 can be externally connected to a measuring device, such as a pressure gauge, to detect the outlet pressures of the first shuttle valve 612i and the second shuttle valve 612j.

[0104] It should be noted that the above descriptions of the valve ports of the travel switching valve 610 and the reversing oil ports of the reversing valve 620 are all examples, and the connection and arrangement of each valve port can be adjusted and changed according to the specific design. Therefore, the above examples are not intended to limit the scope of protection of this application.

[0105] In this embodiment, the control method includes wheel forward control, wheel backward control, track forward control and track backward control.

[0106] First, when the electromagnets of the first control valve 210a and the second control valve 210b on the first closed pump module 200a and the second closed pump module 200b are not energized (both the left position a and the right position b are not energized), no hydraulic oil flows out of the pump bodies of the first closed pump module 200a and the second closed pump module 200b. When the electromagnets on the right position b of the first control valve 210a and the second control valve 210b are energized, as shown in FIG. Figure 4 As shown, the high-pressure hydraulic oil flows out from the first pump oil port VA1 of the first closed pump module 200a and the third pump oil port VA2 of the second closed pump module 200b and respectively flows into the first valve port VA and the third valve port VAA of the travel switching valve 610; conversely, when the electromagnets on the left position a of the first control valve 210a and the second control valve 210b are energized, the high-pressure hydraulic oil flows out from the second pump oil port VB1 of the first closed pump module 200a and the fourth pump oil port VB2 on the second closed pump module 200b and respectively flows into the second valve port VB and the fourth valve port VBB of the travel switching valve 610.

[0107] When executing wheel forward control, the first closed pump module 200a is controlled to supply oil to the first oil circuit unit 601 through the first pump oil port VA1, and the second closed pump module 200b is controlled to supply oil to the third oil circuit unit 603 through the third pump oil port VA2. The switching valve module 600 then controls the first oil circuit unit 601 and the third oil circuit unit 603 to simultaneously supply oil to the corresponding forward oil filling ports of the first wheel drive unit 410a and the second wheel drive unit 410b to achieve forward drive.

[0108] When executing wheel reverse control, the first closed pump module 200a is controlled to supply oil to the second oil circuit unit 602 through the corresponding second pump oil port VB1, and the second closed pump module 200b is controlled to supply oil to the fourth oil circuit unit 604 through the corresponding fourth pump oil port VB2. The switching valve module 600 then controls the second oil circuit unit 602 and the fourth oil circuit unit 604 to simultaneously supply oil to the corresponding reverse oil filling ports of the first wheel drive unit 410a and the second wheel drive unit 410b to achieve reverse drive.

[0109] Specifically, in the wheel travel mode, the electromagnet of the reversing valve 620 is not energized in the default state, and the valve core of the reversing valve 620 remains in the right position to work. When the electromagnets on the right position b of the first control valve 210a and the second control valve 210b are energized, the high-pressure hydraulic oil flowing out of the first pump oil port VA1 and the third pump oil port VA2 enters the first oil circuit unit 601 and the third oil circuit unit 603 of the travel switching valve 610 from the first valve port VA and the third valve port VAA, wherein a part of the pressure oil of the first oil circuit unit 601 and the third oil circuit unit 603 passes through the internal oil channel of the valve body 611 through the first shuttle valve 612i and the second shuttle valve 612j and then flows out from the thirteenth valve port M to enter the third reversing oil port T3 of the reversing valve 620, and then flows from the second reversing oil port T2 of the reversing valve 620 to the sixteenth valve port M3 of the valve body 611, and finally acts on the control ends of the second cartridge valve 612b, the third cartridge valve 612c, the sixth cartridge valve 612f and the seventh cartridge valve 612g to adjust the pressure of the second cartridge valve 612b, the third cartridge valve 612c, the sixth cartridge valve 612f and the seventh cartridge valve 612g. The A and B ports of the sixth cartridge valve 612f and the seventh cartridge valve 612g are cut off; at the same time, the pressure oil at the control end of the first cartridge valve 612a, the fourth cartridge valve 612d, the fifth cartridge valve 612e and the eighth cartridge valve 612h flows out through the seventeenth valve port M4 of the valve body 611 and the fourth reversing oil port T4 and the first reversing oil port T1 of the reversing valve 620 and returns to the oil tank 100. In this way, the first cartridge valve 612a, the fourth cartridge valve 612d, the fifth cartridge valve 612e and the eighth cartridge valve 612h are The A and B ports of the first oil circuit unit 601 and the third oil circuit unit 603 are connected, and the pressure oil in the first oil circuit unit 601 and the third oil circuit unit 603 can flow out from the fifth valve port V1A and the ninth valve port V1AA of the valve body 611 through the first cartridge valve 612a and the fifth cartridge valve 612e respectively, and act on the forward oil injection port R of the first wheel drive unit 410a and the second wheel drive unit 410b, thereby driving the motor to rotate forward and the whole vehicle moves forward. The return oil of the first wheel drive unit 410a and the first wheel drive unit 410a flows out from the reverse oil injection port L, and is connected to the seventh valve port V1B and the eleventh valve port V1BB of the valve body 611 through the pipeline respectively, and flows back to the corresponding first closed pump module 200a and the second closed pump module 200b through the fourth cartridge valve 612d and the eighth cartridge valve 612h respectively. When the electromagnets on the left position a of the first control valve 210a and the second control valve 210b are energized, the high-pressure hydraulic oil flowing out of the second pump oil port VB1 and the fourth pump oil port VB2 enters the second oil circuit unit 602 and the fourth oil circuit unit 604 of the travel switching valve 610 from the second valve port VB and the fourth valve port VBB, and then passes through the fourth cartridge valve 612d and the eighth cartridge valve 612h and the seventh valve port V1B and the eleventh valve port V1BB of the valve body 611 to act on the reversing oil filling port L of the first wheel drive unit 410a and the second wheel drive unit 410b respectively, driving the motor to rotate in the opposite direction, and the whole vehicle moves backward.

[0110] When the track is advanced, the first closed pump module 200a is controlled to supply oil to the first oil circuit unit 601 through the corresponding first pump oil port VA1, and the second closed pump module 200b is controlled to supply oil to the third oil circuit unit 603 through the corresponding third pump oil port VA2. Then, the switching valve module 600 controls the first oil circuit unit 601 and the third oil circuit unit 603 to supply oil to the corresponding first track drive unit 420a and the second track drive unit 420b forward oil injection port at the same time, so as to realize the forward drive.

[0111] When the track is in reverse control, the first closed pump module 200a is controlled to supply oil to the second oil circuit unit 602 through the corresponding second pump oil port VB1, and the second closed pump module 200b is controlled to supply oil to the fourth oil circuit unit 604 through the corresponding fourth pump oil port VB2, and then the switching valve module 600 controls the second oil circuit unit 602 and the fourth oil circuit unit 604 to supply oil to the corresponding first track driving unit 420a and the second track driving unit 420b reverse oil injection port at the same time, so as to realize reverse driving.

[0112] Specifically, in the crawler walking mode, when the electromagnet of the reversing valve 620 is energized and maintained, the valve core switches to the left position to work. When the electromagnets on the right position b of the first control valve 210a and the second control valve 210b are energized, the high-pressure hydraulic oil flowing out of the first pump oil port VA1 and the third pump oil port VA2 enters the first oil circuit unit 601 and the third oil circuit unit 603 of the travel switching valve 610 from the first valve port VA and the third valve port VAA, wherein a part of the pressure oil of the first oil circuit unit 601 and the third oil circuit unit 603 passes through the internal oil channel of the valve body 611, passes through the first shuttle valve 612i and the second shuttle valve 612j, and then flows out from the thirteenth valve port M to enter the third reversing oil port T3 of the reversing valve 620, and then flows into the seventeenth valve port M4 of the valve body 611 from the fourth reversing oil port T4 of the reversing valve 620, and finally acts on the first cartridge valve 612a, the fourth cartridge valve 612d, the fifth cartridge valve 612e and the eighth cartridge valve 612h to control At the same time, the pressure oil at the control end of the second cartridge valve 612b, the third cartridge valve 612c, the sixth cartridge valve 612f and the seventh cartridge valve 612g flows out back to the oil tank 100 through the sixteenth valve port M3 of the valve body 611 and the second reversing oil port T2 and the first reversing oil port T1 of the reversing valve 620, so that the A and B ports of the second cartridge valve 612b, the third cartridge valve 612c, the sixth cartridge valve 612f and the seventh cartridge valve 612g are connected, so that the pressure oil in the first oil circuit unit 601 and the third oil circuit unit 603 can act on the first crawler drive unit 420a and through the second cartridge valve 612b and the sixth cartridge valve 612f respectively. The forward oil filling port P1 of the second track drive unit 420b drives the motor to rotate forward, and the vehicle moves forward. The return oil of the first track drive unit 420a and the first track drive unit 420a flows out from the reverse oil filling port P2, and is connected back to the eighth valve port V2B and the twelfth valve port V2BB of the valve body 611 through the pipeline, and flows out through the third cartridge valve 612c and the fifth cartridge valve 612e into the corresponding first closed pump module 200a and the second closed pump module 200b. Similarly, when the electromagnet on the left position a of the first control valve 210a and the second control valve 210b is energized, the reverse function can be realized.

[0113] It should be noted that the hydraulic travel system of the wheel-track composite transport vehicle provided in this embodiment has the same technical effects as the above-mentioned embodiment 1. In addition, the travel switching valve 610 in the hydraulic travel system of the wheel-track composite transport vehicle provided in this embodiment has better integration, small size, reduced use of hydraulic components, smaller occupied space, and further simplified system layout. And the switching of different working conditions is realized by the hydraulic control signal of the reversing valve 620, and the switching logic is reliable; the travel switching valve 610 has a compact size and a high degree of integration, a small installation space requirement, and a large flow rate; the cartridge valve is used to replace the traditional slide valve to realize the switching of different oil circuits, and a small flow rate is used to control a large flow rate, which can achieve zero leakage of pressure oil, strong anti-pollution ability, the valve core is not easy to be stuck, the performance is stable, the components are few, and the reliability of using a small flow rate to control a large flow rate is high, and the price is cheaper than the traditional slide valve; the opening pressure of the cartridge valve can be adjusted by changing its spring, so that the oil circuits of the cartridge valves A and B can have back pressure, thereby improving the response of the hydraulic system.

[0114] In this embodiment, the cartridge valve is a two-way cartridge valve. The control end of the cartridge valve has a spring chamber, and the expansion and contraction of the spring in the spring chamber controls the movement of the valve block inserted in the upper chamber, thereby controlling the conduction and cutoff of the cartridge valve.

[0115] Embodiment 3

[0116] See also Figures 1 to 6 This embodiment further provides a transport vehicle. The transport vehicle includes a wheel-track composite chassis and a wheel-track composite transport vehicle hydraulic travel system according to the above-mentioned embodiment 1 or embodiment 2.

[0117] Optionally, the transport vehicle is a wheel-track composite power tower material transport vehicle or an engineering vehicle such as an excavator or a crane.

[0118] It should be noted that in the present application, unless otherwise specified, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like used to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0119] It can be understood by those skilled in the art that the cartridge valve described in this embodiment is a component composed of components with control functions. The valve formed by inserting the valve block mainly realizes the opening or closing of the oil circuit. When used in combination with an ordinary hydraulic control valve, it realizes the control of the direction, pressure and flow of the system oil. The solenoid valve is an industrial device controlled by electromagnetics, which is used in industrial control systems to adjust the direction, flow, speed and other parameters of the medium. The solenoid valve can be used with different circuits to achieve the desired control, and the accuracy and flexibility of the control can be guaranteed. It is a straight-stroke valve, which is a valve that combines the valve body and the actuator into one. It has the advantages of small size and easy installation. In addition, the particularity of the internal piston structure makes the medium pressure have almost no more resistance interference to the piston, thereby achieving fast switching and excellent quality with small pressure loss. A closed hydraulic system, that is, the hydraulic pump and the hydraulic motor are connected through pipelines to form a closed circulation system.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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 the field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A hydraulic travel system for a wheel-track composite transport vehicle, characterized in that: It includes at least two closed travel drive subsystems, and the closed travel drive subsystem includes: Closed pump module (200); A travel drive module (400), comprising a wheel drive unit (410) and a track drive unit (420); and A switching valve module (600) comprises a first oil circuit unit (601) and a second oil circuit unit (602) connected to the closed pump module (200), wherein the first oil circuit unit (601) and the second oil circuit unit (602) are both connected to the wheel drive unit (410) and the track drive unit (420); When executing forward drive, the switching valve module (600) is used to control the first oil circuit unit (601) to selectively inject oil into the forward oil port of the wheel drive unit (410) or the track drive unit (420); when executing reverse drive, the switching valve module (600) is used to control the second oil circuit unit (602) to selectively inject oil into the reverse oil port of the wheel drive unit (410) or the track drive unit (420).

2. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 1 is characterized in that: The switching valve module (600) comprises: A travel switching valve (610), comprising the first oil circuit unit (601) and the second oil circuit unit (602), wherein a first shuttle valve (612i) is provided between the first oil circuit unit (601) and the second oil circuit unit (602); A reversing valve (620) connected to the oil outlet of the first shuttle valve (612i) and a valve port for controlling switching on the travel switching valve (610); When forward driving is performed, the reversing valve (620) is used to control the first oil circuit unit (601) to selectively inject oil into the forward oil port of the wheel drive unit (410) or the track drive unit (420); when reverse driving is performed, the reversing valve (620) is used to control the second oil circuit unit (602) to selectively inject oil into the reverse oil port of the wheel drive unit (410) or the track drive unit (420).

3. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 2 is characterized in that: The travel switching valve (610) comprises a first cartridge valve (612a), a second cartridge valve (612b), a third cartridge valve (612c) and a fourth cartridge valve (612d); The oil inlets of the first cartridge valve (612a) and the second cartridge valve (612b) are both connected to the first pump oil port (VA1) in the closed pump module (200) to form the first oil circuit unit (601); the oil outlet of the first cartridge valve (612a) is connected to the forward oil port of the wheel drive unit (410); and the oil outlet of the second cartridge valve (612b) is connected to the forward oil port of the track drive unit (420); The oil inlets of the third cartridge valve (612c) and the fourth cartridge valve (612d) are both connected to the second pump oil port (VB1) in the closed pump module (200) to form the second oil circuit unit (602); the oil outlet of the third cartridge valve (612c) is connected to the reverse oil port of the track drive unit (420); and the oil outlet of the fourth cartridge valve (612d) is connected to the reverse oil port of the wheel drive unit (410); When executing forward drive or reverse drive, the reversing valve (620) is used to control two of the first cartridge valve (612a), the second cartridge valve (612b), the third cartridge valve (612c) and the fourth cartridge valve (612d) to be selectively turned on.

4. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 2 is characterized in that: The closed travel drive subsystems are provided with two, the switching valve modules (600) in the two closed travel drive subsystems share one reversing valve (620), and the travel switching valves (610) in the two closed travel drive subsystems share a valve body (611); A second shuttle valve (612j) is also provided in the valve body (611), the first shuttle valve (612i) in the valve body (611) is connected to the second shuttle valve (612j), and the port of the second shuttle valve (612j) is connected to the reversing valve (620).

5. The hydraulic travel system of the wheel-track composite transport vehicle according to any one of claims 2 to 4, characterized in that: The reversing valve (620) is a two-position four-way electromagnetic reversing valve (620).

6. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 1, characterized in that: The hydraulic travel system of the wheel-track hybrid transport vehicle further comprises a speed switching valve (500), wherein the speed switching valve (500) is connected to the variable ports of the wheel drive unit (410) and the track drive unit (420), and the speed switching valve (500) is further connected to the oil tank (100) and the closed pump module (200). The speed switching valve (500) controls the speed of the wheel drive unit (410) or the track drive unit (420) by controlling the pressure of the hydraulic oil in the variable port.

7. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 1, characterized in that: The closed travel drive subsystem is provided with two, and the closed pump modules (200) in the two closed travel drive subsystems are connected in series and driven by the same power input module.

8. The hydraulic travel system of the wheel-track composite transport vehicle according to claim 7, characterized in that: The power input module includes an engine and / or a motor.

9. A method for controlling the hydraulic travel system of a wheel-track composite transport vehicle, characterized in that: Applied to the hydraulic walking system of the wheel-track composite transport vehicle according to any one of claims 1 to 8, the control method includes wheel forward control, wheel backward control, track forward control and track backward control; When executing the wheel forward control, the closed pump module (200) is controlled to supply oil to the first oil circuit unit (601), and then the switching valve module (600) controls the first oil circuit unit (601) to inject oil into the forward oil port of the wheel drive unit (410) to achieve forward drive; When executing the wheel backward control, the closed pump module (200) is controlled to supply oil to the second oil circuit unit (602), and then the switching valve module (600) controls the second oil circuit unit (602) to inject oil into the reverse oil port of the wheel drive unit (410) to realize backward drive; When the crawler track forward control is executed, the closed pump module (200) is controlled to supply oil to the first oil circuit unit (601), and then the switching valve module (600) controls the first oil circuit unit (601) to inject oil into the forward oil port of the crawler track drive unit (420) to achieve forward drive; When executing the track backward control, the closed pump module (200) is controlled to supply oil to the second oil circuit unit (602), and then the switching valve module (600) controls the second oil circuit unit (602) to inject oil into the corresponding reverse oil port of the track drive unit (420) to achieve backward drive.

10. A transport vehicle, characterized in that: It comprises a wheel-track composite chassis and a hydraulic travel system of a wheel-track composite transport vehicle according to any one of claims 1-8.

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