Hydraulic system of aircraft refueling vehicle, aircraft refueling vehicle

Abstract

The application discloses a hydraulic system of an aircraft refueling vehicle, the aircraft refueling vehicle and the hydraulic system of the aircraft refueling vehicle. The hydraulic system comprises an oil inlet pipeline, an oil return pipeline and a platform lifting assembly. The oil inlet of a first reversing valve in the platform lifting assembly is connected with the oil inlet pipeline, and the oil return is connected with the oil return pipeline. The first end of a first hydraulic control check valve is connected with the first oil outlet of the first reversing valve, the second end of the first hydraulic control check valve is connected with a platform drive, the control end of the hydraulic control check valve is connected with the second oil outlet of the first reversing valve, one end of a first damping valve is connected with the connection position of the control end of the first hydraulic control check valve and the second oil outlet of the first reversing valve, and the other end of the first damping valve is connected with the oil return pipeline. When the first reversing valve is in a first state, the oil inlet and the first oil outlet are connected; when the first reversing valve is in a second state, the oil inlet and the second oil outlet are connected, and the oil return and the first oil outlet are connected, so that the stability during the platform lifting process is improved.

Description

Technical Field

[0001] This application relates to the field of aviation refueling technology, and in particular to a hydraulic system for an aircraft refueling vehicle and an aircraft refueling vehicle. Background Technology

[0002] Airports are vital transportation hubs connecting cities to the rest of the world. Large airports typically have backup fuel depots and underground refueling pipelines connecting these depots to aircraft parking positions. However, these underground refueling pipelines often cannot extend to every parking position, necessitating the use of aircraft refueling trucks connected to the underground refueling wells and parking positions to supply fuel to aircraft and support the safe and stable operation of the airport.

[0003] Aircraft refueling trucks are equipped with refueling platforms and other upper structures to assist refueling operators in aircraft refueling operations. When refueling is needed, the refueling platform needs to rise to the height of the aircraft's refueling nozzle for easy refueling by the operators. After refueling, the refueling platform needs to descend. However, some technologies suffer from unstable ascent and descent of the refueling platform, affecting the refueling experience for aircraft refueling operators. Utility Model Content

[0004] This application provides a hydraulic system for an aircraft refueling vehicle and an aircraft refueling vehicle to solve at least some of the problems in the related art.

[0005] This application provides a hydraulic system for an aircraft refueling truck, comprising: an oil inlet line, an oil return line, and a platform lifting assembly, wherein the platform lifting assembly includes: The first directional valve has its inlet connected to the inlet pipeline and its return port connected to the return pipeline. A first hydraulic control check valve, wherein the first end of the first hydraulic control check valve is connected to the first oil outlet of the first reversing valve, the second end of the first hydraulic control check valve is connected to the platform drive, and the control end of the hydraulic control check valve is connected to the second oil outlet of the first reversing valve. The first damping valve has an orifice diameter smaller than the orifice diameter limit. One end of the first damping valve is connected to the control end of the first hydraulic check valve and the connection point of the second oil outlet of the first directional valve. The other end of the first damping valve is connected to the return oil pipeline. When the first directional valve is in the first state, the oil inlet and the first oil outlet are connected, and the hydraulic oil drives the platform to rise through the first hydraulically controlled check valve. When the first directional valve is in the second state, the oil inlet and the second oil outlet are connected, and the return oil port and the first oil outlet are connected. The first hydraulically controlled check valve is reversed, and the hydraulic oil between the first hydraulically controlled check valve and the platform flows back to the return oil pipeline through the first hydraulically controlled check valve, the first oil outlet, and the return oil port. The first damping valve is used to reduce the rate of pressure change at the control end of the first hydraulically controlled check valve when the pressure of the hydraulic oil at the second oil outlet decreases.

[0006] Optionally, a second reversing valve and a first one-way throttle valve assembly are further provided between the first hydraulic check valve and the platform. The first one-way throttle valve assembly includes two one-way throttle valves that are in opposite directions. The oil inlet of the second reversing valve is connected to the second end of the first hydraulic check valve, the first oil outlet of the second reversing valve is connected to the platform, the second oil outlet of the second reversing valve is connected to one of the one-way throttle valves, and the other one-way throttle valve is connected to the platform.

[0007] Optionally, a platform drive unit is further provided between the first hydraulic check valve and the platform. The platform drive unit includes a first motor, a second motor, a first hydraulic cylinder, and a second hydraulic cylinder. The first motor and the first hydraulic cylinder are drivenly connected, and the second motor and the second hydraulic cylinder are drivenly connected. The first motor and the second motor are synchronous motors.

[0008] Optionally, the hydraulic system further includes a cantilever lifting assembly, the cantilever lifting assembly comprising: A pressure reducing valve, wherein the first end of the pressure reducing valve is connected to the first oil outlet of the first directional valve; The second hydraulic control check valve has its first end connected to the second end of the pressure reducing valve, its second end connected to the cantilever, and its control end connected to the second oil outlet of the first directional valve. The third hydraulic control check valve has its first end connected to the return oil pipeline, its second end connected to the first end of the first hydraulic control check valve, and its control end connected to the second oil outlet of the first directional valve. The second damping valve has one end connected to the control end of the second hydraulic check valve, the control end of the third hydraulic check valve, and the connection between the second oil outlet of the first directional valve, and the other end connected to the return oil pipeline.

[0009] Optionally, the cantilever lifting assembly further includes a third directional valve, the oil inlet of which is connected to one end of the first damping valve, the oil return port of which is connected to the oil return pipeline, and the first oil outlet of which is connected to the control end of the second hydraulic check valve and the connection point between the control end of the third hydraulic check valve and one end of the second damping valve. When the third directional valve is in the first state, the oil inlet and the first oil outlet of the third directional valve are connected to connect the second oil outlet of the first directional valve and the control end of the second hydraulic check valve and the control end of the third hydraulic check valve. When the third directional valve is in the second state, the first oil outlet and the oil return port of the third directional valve are connected to connect the oil return pipeline and the control end of the second hydraulic check valve and the control end of the third hydraulic check valve.

[0010] Optionally, a first manual valve is further provided between the second end of the first hydraulically controlled one-way terminal and the return oil line; and / or A second manual valve is also provided between the second end of the second hydraulic check valve and the return oil line.

[0011] Optionally, the hydraulic system further includes a well hose lifting assembly, which includes: Multiple well hose drive components, each of the well hose drive components including an upstream one-way throttle valve, a downstream one-way throttle valve, a fourth hydraulically controlled one-way valve, and a well hose cylinder; the first ends of the upstream one-way throttle valve and the fourth hydraulically controlled one-way valve are connected, the second end of the fourth hydraulically controlled one-way valve is connected to the well hose cylinder, and the well hose cylinder is connected to the downstream one-way throttle valve; The fourth directional valve has its inlet connected to the inlet pipeline and its outlet connected to the return pipeline. The second outlet of the fourth directional valve is connected to the plurality of upstream one-way throttle valves, and the first outlet of the fourth directional valve is connected to the control end of the plurality of fourth hydraulic check valves.

[0012] Optionally, the hydraulic system further includes an oil tank, a manual booster, a three-way valve, and two check valves. One end of the manual booster is connected to the oil tank, and the other end of the manual booster is connected to the input end of the three-way valve. One output end of the three-way valve is connected to the plurality of upstream one-way throttle valves via one of the check valves, and the other output end of the three-way valve is connected to the platform drive via the other check valve.

[0013] Optionally, the hydraulic system further includes a rotary winding assembly, the rotary winding assembly comprising: winding motor; A fifth directional control valve has its inlet connected to the inlet pipeline and its outlet connected to the return pipeline. The second outlet of the fifth directional control valve is connected to the first end of the winding motor, and the first outlet of the fifth directional control valve is connected to the second end of the winding motor. When the fifth directional control valve is in its first state, it connects the inlet and second outlet, and connects the return pipeline and the first outlet. When the fifth directional control valve is in its second state, it connects the inlet, the first outlet, and the second outlet.

[0014] Optionally, a valve and a second one-way throttle valve assembly are also provided between the second end of the winding motor and the second oil outlet of the fifth reversing valve, the second one-way throttle valve assembly including two one-way throttle valves connected to each other in opposite directions.

[0015] Optionally, the hydraulic system further includes a pump drive assembly, which includes a pump. The first end of the pump is connected to the third outlet of the first directional valve, and the second end of the pump is connected to the return line. When the first directional valve is in the third state, the inlet and the third outlet of the first directional valve are connected.

[0016] Optionally, the hydraulic system further includes an air compressor drive assembly, which includes an air compressor and a sixth directional valve. The inlet of the sixth directional valve is connected to the third outlet of the first directional valve, the first outlet of the sixth directional valve is connected to the first end of the oil pump, the second outlet of the sixth directional valve is connected to the first end of the air compressor, and the second end of the air compressor is connected to the return oil line. When the sixth directional valve is in the first state, its inlet and first outlet are connected; when the sixth directional valve is in the second state, its inlet and second outlet are connected.

[0017] Optionally, the hydraulic system further includes an oil tank, a booster pump, a first check valve, a pressure gauge, and a relief valve. One end of the booster pump is connected to the oil tank, and the other end is connected to the first check valve. The first check valve is connected to the pressure gauge. A relief valve is connected between the first check valve and the pressure gauge. The relief valve is connected to the return oil line, and the return oil line is connected to the oil tank.

[0018] Another aspect of this application provides an aircraft refueling vehicle, including a hydraulic system for the aircraft refueling vehicle.

[0019] The hydraulic system of the aircraft refueling truck and the aircraft refueling truck provided in this application include an oil inlet line, an oil return line and a platform lifting assembly. The platform lifting assembly includes a first phase-changing valve, a first hydraulically controlled check valve and a first damping valve.

[0020] The inlet of the first directional valve is connected to the inlet pipeline, and the return port of the first directional valve is connected to the return pipeline; the first end of the first hydraulic check valve is connected to the first outlet of the first directional valve, the second end of the first hydraulic check valve is connected to the platform drive, and the control end of the hydraulic check valve is connected to the second outlet of the first directional valve.

[0021] When the first directional valve is in its first state, the inlet and outlet ports are connected, and hydraulic oil drives the platform to rise through the first pilot-operated check valve. During the platform's ascent, because the first pilot-operated check valve is unidirectionally open, the hydraulic oil can only move from the first end to the second end of the first pilot-operated check valve, and cannot move from the second end to the first end. Therefore, when the platform rises or reaches a fixed height, it prevents the platform from falling back, improving the stability of the platform during ascent and height maintenance.

[0022] When the first directional valve is in its second state, the inlet and outlet ports are connected, as are the return port and the first outlet port. Because the control end of the first pilot-operated check valve is connected to the second outlet port of the first directional valve, the first pilot-operated check valve is reverse-biased, allowing hydraulic oil to move from the second end to the first end of the first pilot-operated check valve. The hydraulic oil between the first pilot-operated check valve and the platform flows back to the return line through the first pilot-operated check valve, the first outlet port, and the return port, causing the platform to descend under gravity.

[0023] The orifice diameter of the first damping valve is smaller than the orifice diameter limit. The first damping valve is connected to the control end of the first hydraulic check valve and the second oil outlet of the first directional valve. The other end of the first damping valve is connected to the return oil line. When the pressure at the second oil outlet of the first directional valve decreases, the rate of pressure decrease at the control end of the first hydraulic check valve is reduced, allowing the platform to stop slowly during descent. This avoids platform swaying caused by sudden stops during descent and improves the platform's operational stability during descent. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0025] Figure 1 This is a schematic diagram of the hydraulic system of an aircraft refueling truck according to one embodiment of this application; Figure 2 This is a schematic diagram of the hydraulic system of an aircraft refueling truck according to one embodiment of this application; Figure 3 for Figure 2The diagram shows the structure of the hydraulic system well hose lifting assembly of the aircraft refueling truck. Figure 4 for Figure 2 The diagram shows the structure of the rotary rewind assembly of the hydraulic system of the aircraft refueling truck.

[0026] Figure Descriptions: 2. Hydraulic System; 21. Inlet Oil Pipe; 22. Return Oil Pipe; 3. Platform Lifting Assembly; 31. First Directional Control Valve; 32. First Hydraulic Control Check Valve; 33. First Damping Valve; 34. Second Directional Control Valve; 35. First One-Way Throttle Valve Assembly; 36. Platform Drive Component; 361. First Motor; 362. Second Motor; 363. First Cylinder; 364. Second Cylinder; 47. Cantilever Lifting Assembly; 41. Pressure Reducing Valve; 42. Second Hydraulic Control Check Valve; 43. Third Hydraulic Control Check Valve; 44. Second Damping Valve; 45. Third Directional Control Valve; 46. First Manual Valve; 47. Second Manual Valve; Well Hose. Lifting assembly 5, well hose drive assembly 51, upstream one-way throttle valve 52, downstream one-way throttle valve 53, fourth hydraulic control one-way valve 54, well hose cylinder 55, fourth directional valve 56, oil tank 61, manual booster 62, three-way valve 63, one-way valve, rotary rewind assembly 7, rewind motor 71, fifth directional valve 72, valve 73, second one-way throttle valve assembly 74, oil pump drive assembly 8, oil pump 81, air compressor drive assembly 82, air compressor 83, sixth directional valve 84, booster pump 91, first one-way valve 92, pressure gauge 93, relief valve 94. Detailed Implementation

[0027] This application provides a hydraulic system for an aircraft refueling truck and the aircraft refueling truck itself. The hydraulic system and the aircraft refueling truck of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0028] An aircraft refueling truck is a vehicle used to refuel aircraft on the tarmac. The tarmac typically has a well site, and the aircraft refueling truck includes components such as a well hose, turntable, platform, cantilever, and pump. During refueling, the well hose is lowered into the well or connected to the well valve. The well hose connects to the refueling hose, which is then wound up on the turntable. The platform rises to transport refueling personnel to the vicinity of the aircraft's refueling port. The cantilever rises, bringing the refueling end of the refueling hose up to the vicinity of the aircraft's refueling port, allowing personnel to align the refueling end of the hose with the aircraft's refueling port. Then, the pump operates, filling the aircraft's refueling port with aviation fuel from the well through the well hose and the refueling hose. After refueling, the platform and cantilever lower, the well hose rises back to its original position, and the refueling hose is wound up.

[0029] For ease of control, components such as the well hoses, turntable, platform cantilever, and oil pump are all hydraulically controlled. However, in related technologies, the refueling platform suffers from unstable lifting and lowering, affecting the refueling experience for aircraft refueling operators.

[0030] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the hydraulic system 2 of an aircraft refueling truck according to one embodiment of this application. Figure 1 As shown, the hydraulic system 2 of the aircraft refueling vehicle provided in this application includes: an oil inlet pipe 21, an oil return pipe 22, and a platform lifting assembly 3. High-pressure hydraulic oil flows in the oil inlet pipe 21 to drive the platform lifting assembly 3. The oil return pipe 22 is connected to the oil tank 61 to facilitate the return of hydraulic oil to the oil tank 61.

[0031] Platform lifting component 3 includes: The first directional valve 31 has its inlet P connected to the inlet pipeline 21 and its return port T connected to the return pipeline 22. The first hydraulic check valve 32 has its first end connected to the first oil outlet A of the first directional valve 31, its second end connected to the platform drive, and its control end connected to the second oil outlet B of the first directional valve 31. The first damping valve 33 has one end connected to the control end of the first hydraulic check valve 32 and the connection point of the second oil outlet B of the first directional valve 31, and the other end connected to the return oil pipeline 22. When the first directional valve 31 is in the first state, the inlet port P and the first outlet port A are connected, and the hydraulic oil drives the platform to rise through the first pilot-operated check valve 32. During the platform's ascent, because the first pilot-operated check valve 32 is unidirectionally open, the hydraulic oil can only move from the first end of the first pilot-operated check valve 32 to the second end, and cannot move from the second end of the first pilot-operated check valve 32 to the first end. Therefore, when the platform rises or reaches a fixed height, it can prevent the platform from falling back, improving the stability of the platform during ascent and height maintenance.

[0032] When the first directional valve 31 is in the second state, it connects the inlet port P and the second outlet port B, and connects the return port T and the first outlet port A. Because the control end of the first hydraulically controlled check valve 32 is connected to the second outlet port B of the first directional valve 31, the first hydraulically controlled check valve 32 is reverse-biased. Hydraulic oil can move from the second end to the first end of the first hydraulically controlled check valve 32. The hydraulic oil between the first hydraulically controlled check valve 32 and the platform flows back to the return line 22 through the first hydraulically controlled check valve 32, the first outlet port A, and the return port T, causing the platform to descend under gravity. Thus, the descent control of the platform can be achieved simply by controlling the first directional valve 31 to switch from the first state to the second state, making the control method simple. In some embodiments, the first directional valve 31 is a pneumatically controlled directional valve; in other embodiments, the first directional valve 31 is an electrically controlled directional valve. This application does not impose any limitations on this.

[0033] The orifice diameter of the first damping valve 33 is smaller than the orifice diameter limit. The first damping valve 33 is connected to the control end of the first hydraulic check valve 32 and the connection point of the second oil outlet B of the first directional valve 31. The other end of the first damping valve 33 is connected to the return oil line 22. The first damping valve 33 is used to reduce the rate of pressure change at the control end of the first hydraulic check valve 32 when the pressure of the hydraulic oil at the second oil outlet B decreases. This allows the platform to stop slowly during descent, avoiding platform swaying caused by sudden stops and improving the platform's operational stability during descent.

[0034] In this embodiment, the first damping valve 33 is a valve with a small through hole. One end of the first damping valve 33 is connected to the second oil outlet B of the first directional valve 31, and the other end is connected to the return oil line 22. When the first directional valve 31 is in the second state, the second oil outlet B of the first directional valve 31 is connected to the oil inlet P, and there is hydraulic pressure at the second oil outlet B. At this time, the first damping valve 33 can isolate the second oil outlet B of the first directional valve 31 from the return oil line 22, so as to avoid the hydraulic pressure at the second oil outlet B of the first directional valve 31 from affecting the return oil line 22. When the first directional valve 31 switches states, the hydraulic pressure at the second oil outlet B of the first directional valve 31 decreases or even disappears. Because the first damping valve 33 is a valve with a small through hole, the flow and pressure flow away are slower, which can reduce the rate at which the pressure at the control end of the first hydraulic control check valve 32 disappears. Thus, when the first directional valve 31 is not in the second state and the hydraulic pressure at the second oil outlet B disappears, the control platform can stop descending slowly, thus avoiding platform swaying caused by sudden platform stoppage.

[0035] Please continue to refer to this. Figure 1 ,exist Figure 1In the embodiment shown, a second directional valve 34 and a first one-way throttle valve assembly 35 are also provided between the first hydraulic check valve 32 and the platform. The first one-way throttle valve assembly 35 includes two one-way throttle valves that are mutually opposite. The oil inlet P of the second directional valve 34 is connected to the second end of the first hydraulic check valve 32. The first oil outlet A of the second directional valve 34 is connected to the platform. The second oil outlet B of the second directional valve 34 is connected to one of the one-way throttle valves, and the other one-way throttle valve is connected to the platform.

[0036] By configuring a first one-way throttle valve assembly 35, which includes two one-way throttle valves operating in opposite directions, and connecting the second outlet B of the second directional valve 34 to one of the one-way throttle valves, while the other one-way throttle valve is connected to the platform, the speed at which the platform rises and falls can be adjusted.

[0037] A second directional control valve 34 is provided between the first hydraulic check valve 32 and the platform. The inlet P of the second directional control valve 34 is connected to the second end of the first hydraulic check valve 32, the first outlet A of the second directional control valve 34 is connected to the platform, and the second outlet B of the second directional control valve 34 is connected to one of the one-way throttle valves. By controlling the state of the second directional control valve 34, it can be connected to either the first hydraulic check valve 32 and the platform or to the first hydraulic check valve 32 and the first one-way throttle valve assembly 35. When the first one-way throttle valve assembly 35 is functioning properly, the second directional control valve 34 can be controlled to connect to both the first hydraulic check valve 32 and the first one-way throttle valve assembly 35. When the first one-way throttle valve assembly 35 fails and hydraulic oil cannot pass through it, the second directional control valve 34 can be controlled to connect directly to the platform via the first hydraulic check valve 32, thus controlling the platform's ascent and descent.

[0038] exist Figure 1 In the illustrated embodiment, a platform drive unit 36 ​​is further provided between the first hydraulic check valve 32 and the platform. The platform drive unit 36 ​​includes a first motor 361, a second motor 362, a first hydraulic cylinder 363, and a second hydraulic cylinder 364. The first motor 361 and the first hydraulic cylinder 363 are drivenly connected, and the second motor 362 and the second hydraulic cylinder 364 are drivenly connected. The first motor 361 and the second motor 362 are synchronous motors. In this patent application, the first hydraulic cylinder 363 and the second hydraulic cylinder 364 jointly drive the platform to lift and lower. Compared with related technologies that use a single hydraulic cylinder to drive the platform to lift and lower, two hydraulic cylinders can increase the number of connection points with the platform, making the platform more evenly stressed, preventing the platform from tilting during lifting and lowering, and improving the stability of the platform during lifting and lowering.

[0039] By synchronizing the movements of the first hydraulic cylinder 363 and the second hydraulic cylinder 364, in this patent application, the first motor 361 and the second motor 362 are synchronous motors, which allows the driving of the first hydraulic cylinder 363 by the first motor 361 and the driving of the second hydraulic cylinder 364 by the second motor 362 to be synchronized, thus synchronizing the first hydraulic cylinder 363 and the second hydraulic cylinder 364. In this patent application, by connecting the output shafts of the first motor 361 and the second motor 362 together, the first motor 361 and the second motor 362 are made synchronous motors. Figure 2 In the embodiment shown, pressure regulating valves are provided between the first motor 361 and the first oil cylinder 363, and between the second motor 362 and the second oil cylinder 364, which can adjust the pressure entering the first oil cylinder 363 and the pressure entering the second oil cylinder 364, thereby further improving the synchronization between the first oil cylinder 363 and the second oil cylinder 364.

[0040] exist Figure 1 In the illustrated embodiment, the hydraulic system 2 further includes a cantilever lifting assembly 4, which includes: Pressure reducing valve 41, the first end of pressure reducing valve 41 is connected to the first oil outlet A of the first directional valve 31.

[0041] The second hydraulic control check valve 42 has its first end connected to the second end of the pressure reducing valve 41, its second end connected to the cantilever, and its control end connected to the second oil outlet B of the first directional valve 31. The third hydraulic control check valve 43 has its first end connected to the return oil line 22, its second end connected to the first end of the first hydraulic control check valve 32, and its control end connected to the second oil outlet B of the first directional valve 31. The second damping valve 44 has one end connected to the control end of the second hydraulic check valve 42, the control end of the third hydraulic check valve 43, and the connection between the second oil outlet B of the first directional valve 31. The other end of the second damping valve 44 is connected to the return oil line 22.

[0042] Because both the first hydraulically controlled check valve 32 and the second hydraulically controlled check valve 42 are connected to the first outlet A of the first directional control valve 31, the hydraulic oil from the first outlet A of the first directional control valve 31 is used to drive the platform and cantilever to rise. The platform is heavier and requires a higher hydraulic oil pressure, while the cantilever is lighter and requires a lower hydraulic oil pressure compared to the platform. In some specific implementations, the hydraulic oil pressure driving the platform to rise is 11 MPa, and the hydraulic oil pressure driving the cantilever to rise is 6 MPa. In this patent application, by setting a pressure-reducing valve 41, with its first end connected to the first outlet A of the first directional control valve 31 and its first end connected to the second end of the second hydraulically controlled check valve 42, the pressure at the first end of the second hydraulically controlled check valve 42 can be adjusted to match the pressure required to drive the cantilever.

[0043] In this patent application, a second hydraulically controlled check valve 42 and a third hydraulically controlled check valve 43 are provided. The control end of the second hydraulically controlled check valve 42 is connected to the second oil outlet B of the first directional valve 31, and the control end of the third hydraulically controlled check valve 43 is also connected to the second oil outlet B of the first directional valve 31. When the first directional valve 31 is in the second state, the second oil outlet B is pressurized. Both the control ends of the second hydraulically controlled check valve 42 and the third hydraulically controlled check valve 43 are pressurized, thus reversing the flow of the second hydraulically controlled check valve 42 and the third hydraulically controlled check valve 43. The hydraulic oil between the first hydraulically controlled check valve 32 and the cantilever can be connected to the return oil line 22 through the second hydraulically controlled check valve 42 and the third hydraulically controlled check valve 43, allowing the cantilever to descend under gravity.

[0044] The second damping valve 44 is a valve with a small through-hole. When the first directional valve 31 switches states and the hydraulic pressure at the second oil outlet B of the first directional valve 31 disappears, the flow and pressure of the second damping valve 44 are slower because it is a valve with a small through-hole. This reduces the rate at which the pressure disappears at the control ends of the second hydraulic control check valve 42 and the third hydraulic control check valve 43. Consequently, when the first directional valve 31 is not in the second state and the hydraulic pressure at the second oil outlet B disappears, the cantilever can be stopped from descending slowly, thus avoiding the swing of the cantilever caused by a sudden stop.

[0045] In this patent application, the cantilever lifting assembly 4 and the platform lifting assembly 3 share the first oil outlet A of the first reversing valve 31 in the platform lifting assembly 3. This allows the hydraulic oil in the inlet pipe 21 to drive both the platform and the cantilever to rise when the first reversing valve 31 is in its first state. Furthermore, the cantilever lifting assembly 4 and the platform lifting assembly 3 share the second oil outlet B of the first reversing valve 31 in the platform lifting assembly 3. This allows the reversing valve to not only control the first hydraulic check valve 32 to open in reverse, but also to allow the second hydraulic check valve 42 and the third hydraulic check valve 43 to open in reverse, enabling both the platform and the cantilever to descend. This meets the working conditions of the refueling truck, where both the platform and the cantilever need to rise before refueling and descend after refueling.

[0046] like Figure 1 As shown, the cantilever lifting assembly 4 also includes a third directional valve 45. The oil inlet P of the third directional valve 45 is connected to one end of the first damping valve 33, the oil return port T of the third directional valve 45 is connected to the oil return line 22, and the first oil outlet A of the third directional valve 45 is connected to the control end of the second hydraulic check valve 42, the control end of the third hydraulic check valve 43, and the connection point of one end of the second damping valve 44. When the third directional valve 45 is in the first state, the oil inlet P and the first oil outlet A of the third directional valve 45 are connected to the second oil outlet B of the first directional valve 31 and the control end of the second hydraulic check valve 42 and the control end of the third hydraulic check valve 43. When the third directional valve 45 is in the second state, the first oil outlet A and the oil return port T of the third directional valve 45 are connected to the oil return line 22 and the control end of the second hydraulic check valve 42 and the control end of the third hydraulic check valve 43.

[0047] Thus, when it is necessary to avoid sudden stop of the cantilever, the third directional valve 45 can be controlled to the first state. This, through the action of the second damping valve 44, can prevent sudden stop of the cantilever and improve the smoothness of the cantilever's paused descent. In some emergency situations where the cantilever needs to stop immediately, the third directional valve 45 can be controlled to the second state. In this case, the hydraulic oil between the second damping valve 44 and the second hydraulically controlled check valve 42 and the third hydraulically controlled check valve 43 will flow back to the return pipe through the return port T of the third directional valve 45, causing the second hydraulically controlled check valve 42 and the third hydraulically controlled check valve 43 to reverse and prevent further descent of the cantilever.

[0048] exist Figure 1 In the illustrated embodiment, a first manual valve 46 is also provided between the second end of the first hydraulic control check valve 32 and the return oil line 22. Thus, when the first hydraulic control check valve 32 malfunctions, the first directional valve 31 malfunctions, or the hydraulic oil in the inlet oil line 21 is depressurized, preventing the platform from descending, the first manual valve 46 can be manually opened, allowing the hydraulic oil between the second end of the first hydraulic control check valve 32 and the platform to enter the return oil line 22, thereby enabling the platform to descend.

[0049] exist Figure 1 In the illustrated embodiment, a second manual valve 47 is also provided between the second end of the second hydraulic control check valve 42 and the return oil line 22. Thus, when the second hydraulic control check valve 42 malfunctions, or the third hydraulic control check valve 43 malfunctions, or the first directional valve 31 malfunctions, or the hydraulic oil in the inlet oil line 21 is pressureless and the cantilever cannot descend, the second manual valve 47 can be manually opened, allowing the hydraulic oil between the second end of the second hydraulic control check valve and the cantilever to enter the return oil line 22, thereby lowering the cantilever.

[0050] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the hydraulic system 2 of an aircraft refueling truck according to another embodiment of this application. Figure 3 As shown, the hydraulic system 2 also includes a well hose lifting assembly 5, a rotary rewinding assembly 7, an oil pump drive assembly 8, and an air compressor drive assembly 82. The inlet oil line 21 is connected to the well hose lifting assembly 5, the rotary rewinding assembly 7, the oil pump drive assembly 8, and the air compressor drive assembly 82, respectively, to drive the well hose to rise, the rotary rewinding assembly to wind up, the oil pump 81 to operate, and the air compressor 83 to operate. The return oil line 22 is also connected to the well hose lifting assembly 5, the rotary rewinding assembly 7, the oil pump drive assembly 8, and the air compressor drive assembly 82, respectively, to facilitate control of the well hose descent, the reel release, and the operation of the oil pump 81 and the air compressor 83.

[0051] like Figure 2As shown, the hydraulic system 2 also includes an oil tank 61, a booster pump 91, a first check valve 92, a pressure gauge 93, and a relief valve 94. One end of the booster pump 91 is connected to the oil tank 61, and the other end is connected to the first check valve 92. The first check valve 92 is connected to the pressure gauge 93, and a relief valve 94 is connected between the first check valve 92 and the pressure gauge 93. The relief valve 94 is connected to the return oil line 22, and the return oil line 22 is connected to the oil tank 61. The booster pump 91, as the power core, draws low-pressure hydraulic oil from the oil tank 61 and pressurizes it, converting it into high-pressure hydraulic oil that meets the needs of components such as platform lifting, cantilever movement, and well hose drive. In this embodiment, the booster pump 91 is a gear pump, and the booster pump 91 obtains power from the power take-off unit of the fuel truck chassis. The first check valve 92 is connected in series between the booster pump 91 and the downstream pipeline, allowing hydraulic oil to flow only from the booster pump 91 to the inlet pipeline 21, preventing oil from flowing back to the booster pump 91 due to downstream pressure fluctuations. This avoids frequent start-stop of the booster pump 91 and sudden pressure drops, ensuring continuous and stable pressure in the inlet pipeline 21, and thus guaranteeing the continuity of the actions of each actuator. The relief valve 94 is connected in parallel between the first check valve 92 and the pressure gauge 93, with its other end connected to the return pipeline 22. It sets the system's maximum safe pressure threshold. When the relief valve 94 automatically opens, excess high-pressure oil is guided back to the oil tank 61 through the return pipeline 22, quickly reducing the pipeline pressure. The pressure gauge 93 is directly connected to the high-pressure pipeline downstream of the first check valve 92, displaying the system's current operating pressure in real time. Operators can visually determine whether the system pressure is within the normal range using the pressure gauge 93. If the pressure is abnormal, it can be detected promptly by the pressure gauge 93, allowing for timely shutdown and maintenance to prevent minor faults from escalating into system damage.

[0052] Please refer to Figure 3 , Figure 3 for Figure 2 The schematic diagram of the well hose lifting assembly 5 shown is as follows: Figure 3 As shown, the well hose lifting assembly 5 includes: Multiple well hose drive components 51, each well hose drive component 51 includes an upstream one-way throttle valve 52 and multiple downstream well hose drive components 51, each well hose drive component 51 includes an upstream one-way throttle valve 52, a downstream one-way throttle valve 53, a fourth hydraulically controlled one-way valve 54 and a well hose cylinder 55; the first ends of the upstream one-way throttle valve 52 and the fourth hydraulically controlled one-way valve 54 are connected, the second end of the fourth hydraulically controlled one-way valve 54 is connected to the well hose cylinder 55, and the well hose cylinder 55 is connected to the downstream one-way throttle valve 53; The fourth directional valve 56 has an inlet P connected to the inlet pipeline 21 and an outlet connected to the return pipeline 22. The second outlet B of the fourth directional valve 56 is connected to multiple upstream one-way throttle valves 52, and the first outlet A of the fourth directional valve 56 is connected to the control end of multiple fourth hydraulic check valves 54.

[0053] When it is necessary to control the descent of the well hose, the inlet P of the fourth directional valve 56 is connected to the second outlet B. Hydraulic oil in the inlet pipeline 21 flows out from the second outlet B and enters the first end of the fourth hydraulically controlled check valve 54 via the upstream one-way throttle valve 52 (which only throttles in the "inlet direction"). At this time, the fourth hydraulically controlled check valve 54 is forward-biased, and high-pressure oil enters the well hose cylinder 55, driving the well hose cylinder 55 to extend and lower the hose. The upstream one-way throttle valve 52 can control the inlet flow rate by adjusting the throttle opening, stabilizing the hose descent speed within a certain range to match the safe speed of well docking, and preventing the hose from accelerating downward due to its own weight, impacting the well interface, causing hose damage, or deforming the well valve 73.

[0054] When it is necessary to control the rise of the well hose, the inlet P of the fourth directional valve 56 is connected to the first outlet A, and the return port T is connected to the second outlet B. On one hand, high-pressure oil flows from the first outlet A of the fourth directional valve 56 to the control end of the fourth hydraulic check valve 54, pushing the fourth hydraulic check valve 54 to reverse its direction; on the other hand, the high-pressure oil passes through the downstream one-way throttle valve 53 to push the well hose cylinder 55 to contract, and the return oil in the cylinder flows back to the return oil line 22 through the second outlet B. The contraction of the well hose cylinder 55 drives the well hose to rise. The downstream one-way throttle valve 53 can adjust the oil volume from the first outlet A to the well hose cylinder 55, avoiding excessive thrust from the well hose cylinder 55 that would cause the well hose to rise rapidly, preventing the well hose from shaking and colliding with the refueling truck body, boom, or aircraft fuselage; at the same time, it ensures a stable rising speed, making it easy for operators to observe the hose retraction status.

[0055] The fourth hydraulic control check valve 54 is connected in series between the upstream check valve 52 and the well hose cylinder 55. It only allows high-pressure oil to flow from the upstream check valve to the cylinder in the forward direction. When the hose descends to the target position and the fourth directional valve 56 stops supplying oil, the hydraulic control check valve 9264 will automatically close, locking the oil pressure in the cylinder. Even if the hose itself has a tendency to fall due to its own weight, it cannot push the oil back, ensuring that the hose is stable when suspended. There is no need to continuously supply oil to maintain pressure, which reduces energy consumption and avoids well docking failure caused by "slow fall during suspension".

[0056] In this embodiment, there are four well hose drive units 51, which can simultaneously drive four well hoses to rise and fall. In some other embodiments, the number of well hose drive units 51 may be other values, and this application does not limit this.

[0057] Please also refer to Figure 2 and Figure 3The hydraulic system 2 also includes an oil tank 61, a manual booster 62, a three-way valve 63, and two check valves. One end of the manual booster 62 is connected to the oil tank 61, and the other end of the manual booster 62 is connected to the input end of the three-way valve 63. One output end of the three-way valve 63 is connected to multiple upstream one-way throttle valves 52 via one of the check valves, and the other output end of the three-way valve 63 is connected to the platform drive via another check valve.

[0058] If the main hydraulic system 2 (such as a malfunction of the booster pump 91 or a leak in the oil inlet pipe 21) suddenly fails while the aircraft refueling truck is operating on the tarmac, the well hose will be unable to be raised or lowered, the platform will be unable to be driven, and the refueling operation will be interrupted, potentially affecting flight scheduling. The manual booster 62 and related components are designed to form an emergency power source.

[0059] When the well hose and platform are unable to operate due to a malfunction in the main hydraulic system 2, the operator can manually draw hydraulic oil from the oil tank 61 using the booster pump 62 and pressurize it. The oil is then switched via the three-way valve 63 to either the well hose passage, the platform passage, or both passages simultaneously. The high-pressure oil is then delivered to multiple upstream one-way throttle valves 52 or to the platform via corresponding check valves (to prevent backflow), thereby controlling the platform's ascent and the well hose's descent, allowing refueling operations to commence. This prevents refueling work from being affected by a malfunction in the electric booster pump 91.

[0060] Please refer to Figure 4 , Figure 4 for Figure 2 A schematic diagram of the rotary winding assembly 7 in the hydraulic system 2 is shown. Figure 4 In the illustrated embodiment, the rotary take-up assembly 7 includes: 71 winding motor; The fifth directional valve 72 has its inlet P connected to the inlet pipeline 21 and its outlet connected to the return pipeline 22. The second outlet B of the fifth directional valve 72 is connected to the first end of the winding motor 71, and the first outlet A of the fifth directional valve 72 is connected to the second end of the winding motor 71. When the fifth directional valve 72 is in its first state, it connects the inlet P and the second outlet B, as well as the return pipeline T and the first outlet A. When the fifth directional valve 72 is in its second state, it connects the inlet P, the first outlet A, and the second outlet B.

[0061] When the fifth directional valve 72 is in the first state, its internal oil circuit connects "oil inlet P - second oil outlet B" and "oil return port T - first oil outlet A". High-pressure oil flows from the oil inlet pipe 21 into the oil inlet P of the fifth directional valve 72, and is delivered to the first end of the winding motor 71 through the second oil outlet B, driving the winding motor 71 to rotate in the forward direction. At the same time, the return oil from the second end of the winding motor 71 flows into the return oil pipe 22 through the first oil outlet A and the return oil outlet T, forming a complete oil circuit circulation. In this state, the winding motor 71 can stably output torque to drive the turntable to wind up the hose at a uniform speed. After operation, the scattered hose can be retrieved to the turntable to avoid hose dragging and wear.

[0062] When the fifth directional valve 72 is in the second state, its internal oil circuit is connected to "oil inlet P - first oil outlet A - second oil outlet B", and the return oil port T remains open. High-pressure oil flows into both the first and second ends of the winding motor 71 simultaneously. The winding motor 71 is balanced at both ends and cannot generate effective torque, thus achieving an emergency stop of the winding motor 71. Excess oil in the winding motor 71 can flow back to the oil tank 61 through the return oil port T, preventing a sudden increase in pressure inside the motor from damaging the seals, achieving unloading protection, and extending the motor's service life. The operator can manually release the oil hose by pulling it. Compared to the electric release method, the manual release method avoids the problem of the oil hose becoming tangled due to excessive release.

[0063] exist Figure 4 In the embodiment shown, a valve 73 and a second one-way throttle valve assembly 74 are also provided between the second end of the winding motor 71 and the second oil outlet B of the fifth reversing valve 72, which are connected in sequence. The second one-way throttle valve assembly 74 includes two one-way throttle valves connected to each other in opposite directions.

[0064] Thus, by setting valve 73, when the fifth reversing valve 72 is in the first state controlling the winding motor 71 to rotate and wind the oiling hose, the winding motor 71 can be stopped from winding the oiling hose. If an obstacle is needed during the winding process, valve 73 can be controlled to cut off the passage between the second end of the winding motor 71 and the first oil outlet A, so that the winding motor 71 stops rotating. After the obstacle is cleared, valve 73 can be opened to connect the passage between the second end of the winding motor 71 and the first oil outlet A, so that the winding motor 71 continues to rotate and wind the oiling hose.

[0065] By setting a second one-way throttle valve assembly 74, which includes two one-way throttle valves connected to each other in opposite directions, the rotation speed of the winding motor 71 can be controlled, thereby controlling the winding speed of the reel.

[0066] Please refer to Figure 2 ,exist Figure 2In the embodiment shown, the hydraulic system 2 further includes an oil pump drive assembly 8, which includes an oil pump 81. The first end of the oil pump 81 is connected to the third oil outlet of the first directional valve 31, and the second end of the oil pump 81 is connected to the return oil pipeline 22. When the first directional valve 31 is in the third state, the oil inlet P of the first directional valve 31 and the third oil outlet are connected.

[0067] When the first directional valve 31 is in the third state, the oil inlet P of the first directional valve 31 is connected to the third oil outlet, and the hydraulic oil in the oil inlet pipe enters the first end of the oil pump 81, pushing the oil pump 81 to rotate in the forward direction; at the same time, the return oil from the second end of the oil pump 81 enters the return oil pipeline 22, forming a complete oil circuit circulation.

[0068] In this patent application, the first oil outlet A of the first reversing valve 31 is connected to the platform lifting assembly 3 and the cantilever lifting assembly 4, and the third oil outlet of the first reversing valve 31 is connected to the oil pump drive assembly 8. Thus, when the reversing valve is in the first state, the platform and cantilever are controlled to rise, and when the first reversing valve 31 is in the second state, the platform and cantilever are controlled to fall. Furthermore, when the first reversing valve 31 is in the third state, the oil pump 81 is controlled to work, which conforms to the working condition that the oil pump 81 does not work when the platform and cantilever are raised and lowered during the use of the refueling truck, and only starts working when the platform and cantilever are raised to the correct position.

[0069] Please refer to this again. Figure 2 The hydraulic system 2 also includes an air compressor drive assembly 82, which includes an air compressor 83 and a sixth directional valve 84. The oil inlet P of the sixth directional valve is connected to the third oil outlet of the first directional valve 31. The first oil outlet A of the sixth directional valve 84 is connected to the first end of the oil pump 81. The second oil outlet B of the sixth directional valve 84 is connected to the first end of the air compressor 83. The second end of the air compressor 83 is connected to the return oil line 22. When the sixth directional valve 84 is in the first state, the oil inlet P of the sixth directional valve 84 and the first oil outlet A are connected. When the sixth directional valve 84 is in the second state, the oil inlet P of the sixth directional valve 84 and the second oil outlet B are connected.

[0070] When the first directional valve 31 is in the third state, connecting the inlet P to the third outlet, and the sixth directional valve 84 is switched to the second state, connecting the inlet P to the second outlet B, high-pressure hydraulic oil is directed from the inlet pipe 21 through the third outlet of the first directional valve 31 and the second outlet B of the sixth directional valve 84 to the first end of the air compressor 83, driving the rotor of the air compressor 83 to rotate at high speed and generate a stable high-pressure air source. When the air compressor 83 is running, the hydraulic oil driving its operation flows into the return pipe 22 from the second end after completing the power output, and finally flows back to the oil tank 61, preventing the oil from becoming pressurized inside the air compressor 83.

[0071] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0072] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A hydraulic system for an aircraft refueling truck, characterized in that, include: Oil inlet pipeline, oil return pipeline, and platform lifting assembly, wherein the platform lifting assembly includes: The first directional valve has its inlet connected to the inlet pipeline and its return port connected to the return pipeline. A first hydraulic control check valve, wherein the first end of the first hydraulic control check valve is connected to the first oil outlet of the first reversing valve, the second end of the first hydraulic control check valve is connected to the platform drive, and the control end of the hydraulic control check valve is connected to the second oil outlet of the first reversing valve. The first damping valve has an orifice diameter smaller than the orifice diameter limit. One end of the first damping valve is connected to the control end of the first hydraulic check valve and the connection point of the second oil outlet of the first directional valve. The other end of the first damping valve is connected to the return oil pipeline. When the first directional valve is in the first state, the oil inlet and the first oil outlet are connected, and the hydraulic oil drives the platform to rise through the first hydraulically controlled check valve. When the first directional valve is in the second state, the oil inlet and the second oil outlet are connected, and the return oil port and the first oil outlet are connected. The first hydraulically controlled check valve is reversed, and the hydraulic oil between the first hydraulically controlled check valve and the platform flows back to the return oil pipeline through the first hydraulically controlled check valve, the first oil outlet, and the return oil port. The first damping valve is used to reduce the rate of pressure change at the control end of the first hydraulically controlled check valve when the pressure of the hydraulic oil at the second oil outlet decreases.

2. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, A second directional valve and a first one-way throttle valve assembly are also provided between the first hydraulic check valve and the platform. The first one-way throttle valve assembly includes two one-way throttle valves that are in opposite directions. The oil inlet of the second directional valve is connected to the second end of the first hydraulic check valve. The first oil outlet of the second directional valve is connected to the platform. The second oil outlet of the second directional valve is connected to one of the one-way throttle valves. The other one-way throttle valve is connected to the platform.

3. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, A platform drive unit is also provided between the first hydraulic check valve and the platform. The platform drive unit includes a first motor, a second motor, a first hydraulic cylinder, and a second hydraulic cylinder. The first motor and the first hydraulic cylinder are drivenly connected, and the second motor and the second hydraulic cylinder are drivenly connected. The first motor and the second motor are synchronous motors.

4. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, The hydraulic system further includes a cantilever lifting assembly, which includes: A pressure reducing valve, wherein the first end of the pressure reducing valve is connected to the first oil outlet of the first directional valve; The second hydraulic control check valve has its first end connected to the second end of the pressure reducing valve, its second end connected to the cantilever, and its control end connected to the second oil outlet of the first directional valve. The third hydraulic control check valve has its first end connected to the return oil pipeline, its second end connected to the first end of the first hydraulic control check valve, and its control end connected to the second oil outlet of the first directional valve. The second damping valve has one end connected to the control end of the second hydraulic check valve, the control end of the third hydraulic check valve, and the connection between the second oil outlet of the first directional valve, and the other end connected to the return oil pipeline.

5. The hydraulic system of the aircraft refueling truck according to claim 4, characterized in that, The cantilever lifting assembly also includes a third directional valve. The oil inlet of the third directional valve is connected to one end of the first damping valve, and the oil return port of the third directional valve is connected to the oil return pipeline. The first oil outlet of the third directional valve is connected to the control end of the second hydraulic check valve, and the connection point between the control end of the third hydraulic check valve and one end of the second damping valve. When the third directional valve is in the first state, the oil inlet and the first oil outlet of the third directional valve are connected to connect the second oil outlet of the first directional valve and the control end of the second hydraulic check valve, and the control end of the third hydraulic check valve. When the third directional valve is in the second state, the first oil outlet and the oil return port of the third directional valve are connected to connect the oil return pipeline and the control end of the second hydraulic check valve, and the control end of the third hydraulic check valve.

6. The hydraulic system of the aircraft refueling truck according to claim 4, characterized in that, A first manual valve is also provided between the second end of the first hydraulic control unidirectional terminal and the return oil line; and / or A second manual valve is also provided between the second end of the second hydraulic check valve and the return oil line.

7. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, The hydraulic system also includes a well hose lifting assembly, which comprises: Multiple well hose drive components, each of the well hose drive components including an upstream one-way throttle valve, a downstream one-way throttle valve, a fourth hydraulically controlled one-way valve, and a well hose cylinder; the first ends of the upstream one-way throttle valve and the fourth hydraulically controlled one-way valve are connected, the second end of the fourth hydraulically controlled one-way valve is connected to the well hose cylinder, and the well hose cylinder is connected to the downstream one-way throttle valve; The fourth directional valve has its inlet connected to the inlet pipeline and its outlet connected to the return pipeline. The second outlet of the fourth directional valve is connected to the plurality of upstream one-way throttle valves, and the first outlet of the fourth directional valve is connected to the control end of the plurality of fourth hydraulic check valves.

8. The hydraulic system of the aircraft refueling truck according to claim 7, characterized in that, The hydraulic system also includes an oil tank, a manual booster, a three-way valve, and two check valves. One end of the manual booster is connected to the oil tank, and the other end of the manual booster is connected to the input end of the three-way valve. One output end of the three-way valve is connected to the plurality of upstream one-way throttle valves via one of the check valves, and the other output end of the three-way valve is connected to the platform drive via the other check valve.

9. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, The hydraulic system also includes a rotary winding assembly, which includes: winding motor; A fifth directional control valve has its inlet connected to the inlet pipeline and its outlet connected to the return pipeline. The second outlet of the fifth directional control valve is connected to the first end of the winding motor, and the first outlet of the fifth directional control valve is connected to the second end of the winding motor. When the fifth directional control valve is in its first state, it connects the inlet and second outlet, and connects the return pipeline and the first outlet. When the fifth directional control valve is in its second state, it connects the inlet, the first outlet, and the second outlet.

10. The hydraulic system of the aircraft refueling truck according to claim 9, characterized in that, A valve and a second one-way throttle valve assembly are also provided between the second end of the winding motor and the second oil outlet of the fifth reversing valve. The second one-way throttle valve assembly includes two one-way throttle valves connected to each other in opposite directions.

11. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, The hydraulic system further includes a pump drive assembly, which includes a pump. The first end of the pump is connected to the third outlet of the first directional valve, and the second end of the pump is connected to the return line. When the first directional valve is in the third state, the inlet and the third outlet of the first directional valve are connected.

12. The hydraulic system of the aircraft refueling truck according to claim 11, characterized in that, The hydraulic system also includes an air compressor drive assembly, which includes an air compressor and a sixth directional valve. The inlet of the sixth directional valve is connected to the third outlet of the first directional valve, the first outlet of the sixth directional valve is connected to the first end of the oil pump, the second outlet of the sixth directional valve is connected to the first end of the air compressor, and the second end of the air compressor is connected to the return oil line. When the sixth directional valve is in the first state, its inlet and first outlet are connected. When the sixth directional valve is in the second state, its inlet and second outlet are connected.

13. The hydraulic system of the aircraft refueling truck according to claim 1, characterized in that, The hydraulic system also includes an oil tank, a booster pump, a first check valve, a pressure gauge, and a relief valve. One end of the booster pump is connected to the oil tank, and the other end is connected to the first check valve. The first check valve is connected to the pressure gauge. A relief valve is connected between the first check valve and the pressure gauge. The relief valve is connected to the return oil line, and the return oil line is connected to the oil tank.

14. An aircraft refueling truck, characterized in that, Includes the hydraulic system of the aircraft refueling vehicle as described in any one of claims 1-13.

Images