A trailer leveling hydraulic system, vehicle and method of trailer leveling thereof

Abstract

The application discloses a kind of exhibition car leveling hydraulic systems, including oil tank, exhibition car leveling oil circuit, oil supply oil circuit and unlocking oil circuit, first front outrigger oil cylinder and second front outrigger oil cylinder in exhibition car leveling oil circuit are all used double-acting type oil cylinder, first rear outrigger oil cylinder and second rear outrigger oil cylinder are all used interference inner locking type oil cylinder, oil supply oil circuit includes variable plunger pump, the oil inlet of variable plunger pump is connected with oil tank, the oil outlet of variable plunger pump is respectively connected with first front outrigger oil cylinder, second front outrigger oil cylinder, first rear outrigger oil cylinder and second rear outrigger oil cylinder and is connected with oil tank by oil return pipe, unlocking oil circuit includes constant displacement gear pump, the oil inlet of constant displacement gear pump is connected with oil tank, the oil outlet of constant displacement gear pump is respectively connected with the unlocking cavity of first rear outrigger oil cylinder and second rear outrigger oil cylinder.This application has the advantages of fast exhibition car leveling speed, reliable support time long in place, low cost.

Description

Technical Field

[0001] This invention relates to the field of vehicle hydraulic system technology, and more specifically, to a hydraulic system for leveling a display vehicle, a vehicle, and a method for leveling a display vehicle. Background Technology

[0002] Currently, vehicle leveling technology is mainly used in military special vehicles, engineering machinery, and other vehicles requiring leveling. Most manufacturers use proportional valves or digital valves to control the leveling outriggers, and the platform's posture support is typically maintained using either hydraulic holding or mechanical locking. Vehicle leveling systems are often compared based on indicators such as leveling time, leveling accuracy, support reliability, working time, and economy. Mechanically held hydraulic cylinders use the mechanical interference principle for holding, while hydraulically held outrigger cylinders use sealed oil for holding. Mechanically held outriggers offer higher support reliability than hydraulically held outriggers; however, due to the addition of mechanical locking components and the use of special coatings for wear resistance, the mechanically locked hydraulic cylinder is longer and more expensive for the same stroke, affecting the overall layout and system economy.

[0003] If all outriggers use mechanically locking hydraulic cylinders as actuators, the system will be economically inefficient and difficult to arrange; if all outriggers use hydraulically retaining cylinders, it will be difficult to maintain the levelness of the tail beam over a long period. Therefore, there are certain contradictions in the performance indicators, support reliability, economy, and installation layout of the exhibition vehicle leveling system.

[0004] Therefore, how to resolve the contradictions in performance indicators, support reliability, economy and installation layout of the vehicle leveling system has become a technical problem that urgently needs to be solved and a key research focus for those skilled in the art. Summary of the Invention

[0005] To address the technical challenges of existing vehicle leveling systems in terms of performance, support reliability, economy, and installation layout, this invention innovatively provides a hydraulic leveling system for vehicle exhibition. The front outrigger cylinders are double-acting cylinders, and the rear outrigger cylinders are interference-fit internal locking cylinders. This system saves manufacturing costs while maintaining the same performance and support reliability. Furthermore, the use of a variable displacement piston pump as the hydraulic power source minimizes energy consumption.

[0006] To achieve the aforementioned technical objectives, this invention discloses a hydraulic system for leveling a display vehicle, including an oil tank and a leveling oil circuit, a supply oil circuit, and an unlocking oil circuit connected to the oil tank. The leveling oil circuit includes a first front outrigger cylinder, a second front outrigger cylinder, a first rear outrigger cylinder, and a second rear outrigger cylinder. Both the first and second front outrigger cylinders are double-acting cylinders, and both the first and second rear outrigger cylinders are interference-fit internal locking cylinders. The supply oil circuit includes a variable displacement piston pump. The inlet of the variable displacement piston pump is connected to the oil tank, and the outlet of the variable displacement piston pump is connected to the first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder, and the second rear outrigger cylinder, respectively. The first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder, and the second rear outrigger cylinder are connected to the oil tank through return oil pipes. The unlocking oil circuit includes a fixed displacement gear pump, the inlet of which is connected to the oil tank, and the outlet of which is connected to the unlocking chamber of the first rear outrigger cylinder and the second rear outrigger cylinder, respectively.

[0007] Furthermore, the present invention provides a hydraulic system for leveling a display vehicle, wherein the leveling oil circuit further includes a first multi-way valve and a second multi-way valve. Both the first and second multi-way valves are double-acting three-position solenoid directional valves with emergency handles. The first two outlets of the first multi-way valve are connected to the positive and negative cavities of the first front outrigger cylinder via a first positive cavity oil pipe and a first negative cavity oil pipe, respectively. The second two outlets of the first multi-way valve are connected to the positive and negative cavities of the second front outrigger cylinder via a second positive cavity oil pipe and a second negative cavity oil pipe, respectively. The first two outlet ports of the second multi-way valve are connected to the positive and negative cavities of the first rear outrigger cylinder via the third positive cavity oil pipe and the third negative cavity oil pipe, respectively. The second two outlet ports of the second multi-way valve are connected to the positive and negative cavities of the second rear outrigger cylinder via the fourth positive cavity oil pipe and the fourth negative cavity oil pipe, respectively. The first and second inlet ports of the first and second multi-way valves are connected to the outlet port of the variable piston pump via the outlet pipe. The first and second return ports of the first and second multi-way valves are connected to the oil tank via the return pipe.

[0008] Furthermore, the present invention provides a hydraulic system for leveling a display vehicle, wherein a second check valve and a third check valve are sequentially installed on the first positive cavity oil pipe according to the flow direction of the hydraulic oil, and a fourth check valve is installed on the first negative cavity oil pipe. The hydraulic control ports of the second and third check valves are both connected to the oil inlet of the fourth check valve, and the hydraulic control port of the fourth check valve is connected to the oil inlet of the second check valve. A fifth check valve and a sixth check valve are sequentially installed on the second positive cavity oil pipe according to the flow direction of the hydraulic oil, and a seventh check valve is installed on the second negative cavity oil pipe. The hydraulic control ports of the fifth and sixth check valves are both connected to the oil inlet of the seventh check valve, and the hydraulic control port of the seventh check valve is connected to the oil inlet of the fifth check valve.

[0009] Furthermore, the present invention provides a hydraulic system for leveling exhibition vehicles, wherein the leveling oil circuit for exhibition vehicles further includes a first safety relief valve and a second safety relief valve, the first safety relief valve being connected in parallel with a fourth check valve, and the second safety relief valve being connected in parallel with a seventh check valve.

[0010] Furthermore, the present invention provides a hydraulic system for leveling a display vehicle, wherein the oil supply circuit further includes a first high-pressure oil filter, a first check valve, a first solenoid directional valve, and a proportional relief valve. The first high-pressure oil filter and the first check valve are installed sequentially on the outlet pipe according to the flow direction of the hydraulic oil. The first solenoid directional valve and the proportional relief valve are installed sequentially on the bypass pressure-building oil pipe between the outlet of the variable displacement piston pump and the oil tank according to the flow direction of the hydraulic oil. When the proportional relief valve is normal, the first solenoid directional valve is open, and the variable displacement piston pump is in a remote-controlled pressure-regulating constant-pressure variable oil supply mode. When the proportional relief valve is stuck at a large opening, the first solenoid directional valve is closed, and the variable displacement piston pump changes from the remote-controlled pressure-regulating constant-pressure variable oil supply mode to a pressure-cut-off constant-pressure variable oil supply mode.

[0011] Furthermore, the present invention provides a hydraulic system for leveling a display vehicle, wherein the unlocking oil circuit further includes a second high-pressure oil filter, an eighth check valve, an electromagnetic relief valve, and a second electromagnetic directional valve. The inlet of the second high-pressure oil filter is connected to the outlet of a fixed displacement gear pump, and the outlet of the second high-pressure oil filter is connected to the inlet of the eighth check valve. The outlet of the eighth check valve is connected to the inlet of the electromagnetic relief valve via a first oil pipe, and the outlet of the electromagnetic relief valve is connected to the oil tank via a second oil pipe. The inlet of the second electromagnetic directional valve is connected to... The oil return port of the second electromagnetic directional valve is connected to the first oil pipe via the third oil pipe, and the oil outlet of the second electromagnetic directional valve is connected to the unlocking chamber of the first and second rear outrigger cylinders via the fifth oil pipe. When the electromagnetic relief valve and the second electromagnetic directional valve are energized simultaneously, the pressure build-up of the quantitative gear pump simultaneously controls the unlocking of the first and second rear outrigger cylinders. When the electromagnetic relief valve and the second electromagnetic directional valve are de-energized simultaneously, the first and second rear outrigger cylinders are locked.

[0012] This invention also discloses a vehicle that utilizes a vehicle leveling hydraulic system. The first and second front outrigger cylinders are symmetrically mounted on the front side of the vehicle frame, and the first and second rear outrigger cylinders are symmetrically mounted on the rear side of the vehicle frame. A level is installed in the middle of the rear beam of the vehicle frame, and the level is used to measure the levelness AN of the rear beam.

[0013] This invention also discloses a method for leveling a vehicle during deployment. The method utilizes the aforementioned vehicle and includes a vehicle leveling step and a vehicle retraction step.

[0014] The vehicle leveling process includes:

[0015] S11. Energize the electromagnetic overflow valve and the second electromagnetic directional valve simultaneously; start the quantitative gear pump to build up pressure, and unlock the first and second rear outrigger cylinders simultaneously.

[0016] S12. Energize the proportional relief valve; start the variable displacement piston pump to enter the remote control pressure regulation constant pressure variable oil supply mode; simultaneously energize the first multi-way valve and the second multi-way valve to reverse direction, the hydraulic oil pumped by the variable displacement piston pump is pumped into the positive chamber of the first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder and the second rear outrigger cylinder respectively, and the hydraulic oil in the reverse chamber of the first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder and the second rear outrigger cylinder flows back to the oil tank; when all the wheels of the vehicle leave the ground, de-energize the first multi-way valve to return to the neutral position;

[0017] S13. Determine whether the vehicle's levelness AN is within the specified threshold based on the level gauge. If yes, do not perform leveling. If no, continue to pump hydraulic oil into the positive chamber of the first or second rear outrigger cylinder with the shorter extension, until the levelness AN measured by the level gauge is within the specified threshold. Then, de-energize the second multi-way valve to return it to the neutral position and shut off the variable piston pump.

[0018] S14. De-energize the electromagnetic overflow valve and the second electromagnetic directional valve simultaneously, shut down the quantitative gear pump, unload the unlocked oil circuit, and lock the first and second rear outrigger cylinders.

[0019] The vehicle recall process includes:

[0020] S21. Energize the proportional relief valve to start the variable piston pump and enter the remote control pressure regulation constant pressure variable oil supply mode; energize the second multi-way valve to reverse the direction, and pump the hydraulic oil into the positive chamber of the first and second rear outrigger cylinders to replenish the pressure. When the first and second rear outrigger cylinders reach the preset pressure, de-energize the second multi-way valve to return to the neutral position.

[0021] S22. Energize the electromagnetic overflow valve and the second electromagnetic directional valve simultaneously; start the quantitative gear pump to build up pressure, and unlock the first and second rear outrigger cylinders simultaneously.

[0022] S23. Simultaneously energize the first multi-way valve and the second multi-way valve to reverse the direction, and pump the hydraulic oil pumped by the variable piston pump into the reverse chambers of the first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder, and the second rear outrigger cylinder, respectively. The hydraulic oil in the positive chambers of the first front outrigger cylinder, the second front outrigger cylinder, the first rear outrigger cylinder, and the second rear outrigger cylinder flows back to the oil tank. When all the wheels of the vehicle are in contact with the ground, simultaneously de-energize the first multi-way valve and the second multi-way valve to return to the neutral position, and shut down the variable piston pump.

[0023] S24. De-energize the electromagnetic overflow valve and the second electromagnetic directional valve simultaneously, shut down the fixed displacement gear pump, unload the unlocked oil circuit, and lock the first and second rear outrigger cylinders.

[0024] Furthermore, in a vehicle leveling method for display vehicles according to the present invention, when the proportional relief valve is normal, the first electromagnetic reversing valve is turned on, and the variable piston pump is in a remote-controlled pressure-regulating constant-pressure variable oil supply mode; when the proportional relief valve is stuck in the large opening, the first electromagnetic reversing valve is turned off, and the variable piston pump changes from the remote-controlled pressure-regulating constant-pressure variable oil supply mode to the pressure cut-off constant-pressure variable oil supply mode.

[0025] Furthermore, in a vehicle leveling method for display vehicles according to the present invention, in S13, if the extension length of the first or second rear outrigger cylinder exceeds the set length and the levelness AN measured by the level instrument is still not within the specified threshold, then the variable piston pump is shut down and an alarm is triggered.

[0026] The beneficial effects of this invention are as follows: The hydraulic system of this invention uses a variable displacement piston pump as the hydraulic power source for the leveling oil circuit of the exhibition vehicle. It has two oil supply modes: remote control pressure regulation constant pressure variable displacement and pressure cut-off constant pressure variable displacement, which can achieve optimized matching of system pressure and flow rate, and minimize energy loss. The front outrigger cylinder uses a double-acting cylinder, and the rear outrigger cylinder uses an interference-fit internal locking cylinder. Compared with the existing scheme where both front and rear outrigger cylinders use interference-fit internal locking cylinders, this can save 30% of the cost. A directional gear pump is used as the hydraulic power source for the unlocking chamber of the rear outrigger cylinder, realizing unlocking before the rear outrigger cylinder actuates. Therefore, this invention can save manufacturing costs while ensuring that the performance indicators and support reliability of the exhibition vehicle leveling system remain unchanged. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a hydraulic system for leveling a display vehicle according to the present invention. Detailed Implementation

[0028] The following is a detailed explanation and description of a hydraulic system for leveling exhibition vehicles according to the present invention, with reference to the accompanying drawings.

[0029] like Figure 1As shown in the figure, this embodiment of the invention discloses a hydraulic system for leveling a display vehicle, specifically including an oil tank 100 and a display vehicle leveling oil circuit 200, an oil supply circuit 300, and an unlocking oil circuit 400 connected to the oil tank 100. The display vehicle leveling oil circuit 200 includes a first front outrigger cylinder 201, a second front outrigger cylinder 202, a first rear outrigger cylinder 203, and a second rear outrigger cylinder 204. Both the first front outrigger cylinder 201 and the second front outrigger cylinder 202 are double-acting cylinders, and both the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are interference-fit internal locking cylinders. The oil supply circuit 300 includes a variable displacement piston pump 301. The oil inlet of 301 is connected to the oil tank 100. The oil outlet of the variable piston pump 301 is connected to the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203, and the second rear outrigger cylinder 204, respectively. The first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203, and the second rear outrigger cylinder 204 are connected to the oil tank through the return oil pipe. The unlocking oil circuit 400 includes a fixed displacement gear pump 401. The oil inlet of the fixed displacement gear pump 401 is connected to the oil tank. The oil outlet of the fixed displacement gear pump 401 is connected to the unlocking chamber of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204, respectively.

[0030] Those skilled in the art will understand that the interference-locked internal locking cylinder adopts an interference mechanical locking method. The locking sleeve is mechanically positioned with the piston rod, and the locking sleeve and cylinder body are interference-fitted. The locking sleeve has an oil groove that communicates with the unlocking chamber. When the unlocking chamber is depressurized, the cylinder body tightly holds the locking sleeve, which is the locked state, allowing the piston rod to support the load for a long time without relative movement. When high-pressure oil is injected into the unlocking chamber, the high-pressure oil expands the cylinder body, creating a gap between the cylinder body and the locking sleeve. The extension and retraction of the piston rod are then controlled by controlling the oil in the forward and reverse chambers.

[0031] During the leveling of the exhibition vehicle, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are first unlocked by the fixed displacement gear pump 401. Then, the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are extended simultaneously by the variable displacement piston pump 301. During leveling, the cylinder with the shorter extension among the rear outrigger cylinders is extended further to achieve leveling of the exhibition vehicle. The variable displacement piston pump 301 has two oil supply modes: remote control pressure regulation constant pressure variable and pressure cut-off constant pressure variable, to achieve stable oil supply. Finally, the fixed displacement gear pump 401 is turned off to lock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 to achieve position holding. During the retraction process, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are first unlocked by the fixed displacement gear pump 401; then, the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203, and the second rear outrigger cylinder 204 are simultaneously retracted by the variable displacement piston pump 301; finally, the fixed displacement gear pump 401 is turned off to lock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204, achieving position holding. In this embodiment, the front outrigger cylinders are double-acting cylinders, and the rear outrigger cylinders are interference-locked cylinders. Compared with the existing scheme where both front and rear outrigger cylinders use interference-locked cylinders, this can save 30% of the cost; the use of a variable displacement piston pump can reduce energy consumption.

[0032] Based on the above embodiments, the leveling oil circuit 200 of the display vehicle in this embodiment also includes a first multi-way valve 205 and a second multi-way valve 206. Both the first multi-way valve 205 and the second multi-way valve 206 are double-position three-position solenoid directional valves with emergency handles. The first two oil outlets of the first multi-way valve 205 are connected to the positive and negative cavities of the first front outrigger cylinder 201 through the first positive cavity oil pipe 207 and the first negative cavity oil pipe 208, respectively. The second two oil outlets of the first multi-way valve 205 are connected to the positive and negative cavities of the second front outrigger cylinder 202 through the second positive cavity oil pipe 209 and the second negative cavity oil pipe 210, respectively. The first two outlet ports of the second multi-way valve 206 are connected to the positive and negative cavities of the first rear outrigger cylinder 203 via the third positive cavity oil pipe 211 and the third negative cavity oil pipe 212, respectively. The second two outlet ports of the second multi-way valve 206 are connected to the positive and negative cavities of the second rear outrigger cylinder 204 via the fourth positive cavity oil pipe 213 and the fourth negative cavity oil pipe 214, respectively. The first and second inlet ports of the first multi-way valve 205 and the second multi-way valve 206 are connected to the outlet port of the variable displacement piston pump 301 via the outlet pipe 215. The first and second return ports of the first multi-way valve 205 and the second multi-way valve 206 are connected to the oil tank 100 via the return pipe 216.

[0033] In this embodiment, the extension and retraction of the front outrigger cylinder and the rear outrigger cylinder can be achieved by switching the first multi-way valve 205 and the second multi-way valve 206, ensuring the reliability of the hydraulic system. The first multi-way valve 205 and the second multi-way valve 206 have the same connection method, making the hydraulic system simpler and easier to install. The minimum stable controllable flow rate of the first multi-way valve 205 and the second multi-way valve 206 is 0.5L / min, and the maximum controllable flow rate is 120L / min. The multi-way valves can enable the cylinders to extend and retract quickly, and can also enable the cylinders to achieve high-precision leveling at extremely low speeds. At the same time, the multi-way valves have built-in handles, which can be used for emergency manual operation. In emergency situations, the emergency handles of the multi-way valves can be used to extend and retract the front outrigger cylinders and the rear outrigger cylinders.

[0034] Based on the above embodiments, in this embodiment, a second check valve 217 and a third check valve 218 are sequentially installed on the first positive cavity oil pipe 207 according to the flow direction of the hydraulic oil. A fourth check valve 219 is installed on the first negative cavity oil pipe 208. The hydraulic control ports of the second check valve 217 and the third check valve 218 are both connected to the oil inlet of the fourth check valve 219, and the hydraulic control port of the fourth check valve 219 is connected to the oil inlet of the second check valve 217. A fifth check valve 220 and a sixth check valve 221 are sequentially installed on the second positive cavity oil pipe 209 according to the flow direction of the hydraulic oil. A seventh check valve 222 is installed on the second negative cavity oil pipe 210. The hydraulic control ports of the fifth check valve 220 and the sixth check valve 221 are both connected to the oil inlet of the seventh check valve 222, and the hydraulic control port of the seventh check valve 222 is connected to the oil inlet of the fifth check valve 220.

[0035] In this embodiment, the purpose of the above configuration is to achieve the positioning and holding function of the first front outrigger cylinder 201 and the second front outrigger cylinder 202. Specifically, the first front outrigger cylinder 201 and the second front outrigger cylinder 202 operate in the same way. Taking the first front outrigger cylinder 201 as an example, when oil is supplied to the positive cavity of the first front outrigger cylinder 201, the second one-way valve 217 and the third one-way valve 218 are open, and hydraulic oil can flow into the positive cavity of the first front outrigger cylinder 201. At this time, pressure is generated at the oil inlet of the second one-way valve 217, causing the fourth one-way valve 219 to open, and hydraulic oil can flow back to the oil tank from the reverse cavity of the first front outrigger cylinder 201, thus achieving the positioning and holding function of the first front outrigger cylinder 201. The hydraulic cylinder 201 extends; after the first front outrigger cylinder 201 extends to its final position, the second check valve 217 and the third check valve 218 close, and the pressure at the oil inlet of the second check valve 217 disappears, causing the fourth check valve 219 to also close. At this time, the oil in the positive chamber of the first front outrigger cylinder 201 is blocked by the second check valve 217 and the third check valve 218, forming a dead chamber, while the oil in the negative chamber of the first front outrigger cylinder 201 is blocked by the fourth check valve 219, thereby achieving the holding position of the first front outrigger cylinder 201. Therefore, in this embodiment, a closed positive chamber of the cylinder is used, and two check valves form a double-stage sealing method. Tests have shown that after 24 hours, the cylinder's retraction displacement is less than 2mm, resulting in a hydraulic system with high reliability and strong holding capability.

[0036] Based on the above embodiments, the leveling oil circuit 200 of the display vehicle in this embodiment also includes a first safety relief valve 223 and a second safety relief valve 224. The first safety relief valve 223 is connected in parallel with the fourth check valve 219, and the second safety relief valve 224 is connected in parallel with the seventh check valve 222.

[0037] In this embodiment, after the first front outrigger cylinder 201 and the second front outrigger cylinder 202 extend to their positions, the oil temperature rises, causing the oil volume to expand and increase. Since the oil volume in the positive cavity of the cylinder is larger than that in the negative cavity, when the temperature difference is too large, the cylinder will tend to extend, squeezing the negative cavity and causing the pressure in the negative cavity to rise, which in turn causes the cylinder to be damaged and deformed. To eliminate this problem, the first safety relief valve 223 and the second safety relief valve 224 are used to limit the pressure of the first front outrigger cylinder 201 and the second front outrigger cylinder 202, respectively. When the pressure in the negative cavity of the cylinder rises to the set pressure of the safety relief valve, the safety relief valve opens and releases pressure in the negative cavity of the cylinder, thereby ensuring the safety of the hydraulic system.

[0038] Based on the above embodiments, the oil supply circuit 300 in this embodiment further includes a first high-pressure oil filter 302, a first check valve 303, a first solenoid directional valve 304, and a proportional relief valve 305. The first high-pressure oil filter 302 and the first check valve 303 are installed sequentially on the outlet pipe 215 according to the flow direction of the hydraulic oil. The first solenoid directional valve 304 and the proportional relief valve 305 are installed sequentially on the bypass pressure-building oil pipe 306 between the outlet of the variable displacement piston pump 301 and the oil tank 100 according to the flow direction of the hydraulic oil. When the proportional relief valve 305 is normal, the first solenoid directional valve 304 is open, and the variable displacement piston pump 301 is in the remote control pressure-regulating constant pressure variable oil supply mode; when the proportional relief valve 305 is stuck at a large opening, the first solenoid directional valve 304 is closed, and the variable displacement piston pump 301 changes from the remote control pressure-regulating constant pressure variable oil supply mode to the pressure cut-off constant pressure variable oil supply mode.

[0039] In this embodiment, the first high-pressure oil filter 302 is used to filter the hydraulic oil in the leveling circuit of the display vehicle; the first check valve 303 is used to prevent hydraulic oil from flowing back into the variable displacement piston pump 301; the proportional relief valve 305 is used to set the working pressure of the variable displacement piston pump 301; the first solenoid directional valve 304 is used to control the on / off state of the pressure building circuit of the variable displacement piston pump 301. When the pressure building circuit is normal, the first solenoid directional valve 304 is in the conducting state, and the proportional relief valve 305 controls the system pressure; when the proportional relief valve 305 is stuck in the large opening, the pressure building circuit loses its function. At this time, the first solenoid directional valve 304 is energized and in the closed state. At this time, the variable displacement piston pump 301 changes from the remote control pressure regulation constant pressure variable oil supply mode to the pressure cut-off constant pressure variable oil supply mode and continues to output flow according to demand, realizing the normal operation of the hydraulic system. This solves the problem that the variable displacement piston pump 301 cannot output high-pressure hydraulic oil when the proportional relief valve 305 is stuck in the large opening, thus improving the reliability of the hydraulic system.

[0040] Based on the above embodiments, the unlocking oil circuit 400 in this embodiment further includes a second high-pressure oil filter 402, an eighth check valve 403, a solenoid relief valve 404, and a second solenoid directional valve 405. The oil inlet of the second high-pressure oil filter 402 is connected to the oil outlet of the fixed displacement gear pump 401. The oil outlet of the second high-pressure oil filter 402 is connected to the oil inlet of the eighth check valve 403. The oil outlet of the eighth check valve 403 is connected to the oil inlet of the solenoid relief valve 404 through a first oil pipe 406. The oil outlet of the solenoid relief valve 404 is connected to the oil tank 100 through a second oil pipe 407. The inlet of the second electromagnetic directional valve 405 is connected to the first oil pipe 406 via the third oil pipe 408, and the return port of the second electromagnetic directional valve 405 is connected to the second oil pipe 407 via the fourth oil pipe 409. The outlet of the second electromagnetic directional valve 405 is connected to the unlocking chambers of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 via the fifth oil pipe 410. When the electromagnetic relief valve 404 and the second electromagnetic directional valve 405 are simultaneously energized, the fixed displacement gear pump 401 builds pressure and simultaneously controls the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 to unlock; when the electromagnetic relief valve 404 and the second electromagnetic directional valve 405 are simultaneously de-energized, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are locked.

[0041] In this embodiment, a specific method is provided for controlling the locking and unlocking of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204. A second solenoid directional valve 405 is used in the unlocking oil circuit to connect the unlocking chamber of the rear outrigger cylinder to the oil tank for unloading. The rear outrigger cylinder can only unlock when both the second solenoid directional valve 405 and the solenoid relief valve 404 are simultaneously energized. This eliminates the problem of abnormal pressure build-up in the unlocking oil circuit due to abnormal energization of the solenoid relief valve 404, which could cause the rear outrigger cylinder to unlock, leading to changes in the tail beam's levelness and potentially causing a major safety accident. This improves the safety and reliability of the hydraulic system.

[0042] In summary, the present invention has the following advantages:

[0043] 1. The leveling accuracy of the tail beam under all working conditions shall be less than or equal to 5'. The leveling time of the tail beam on a horizontal road surface shall not exceed 25s, the leveling time of the tail beam on a 2° cross slope shall not exceed 40s, and the leveling time of the tail beam on a 2° longitudinal slope shall not exceed 40s.

[0044] 2. After the exhibition vehicle has been leveled for 24 hours, the retraction displacement of the first front outrigger cylinder 201 and the second front outrigger cylinder 202 is less than 2mm, which meets the working requirements.

[0045] 3. After the exhibition vehicle was leveled for 24 hours, the levelness of the tail beam did not change, and the displacement of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 did not change, meeting the requirements for reliable support.

[0046] 4. The pressure in the reverse chamber of the first front outrigger cylinder 201 and the second front outrigger cylinder 202 is limited to 25 MPa. After the exhibition vehicle is leveled, the temperature rise changes by about 20°C. The first front outrigger cylinder 201 and the second front outrigger cylinder 202 are not damaged or deformed.

[0047] 5. The phenomenon of abnormal unlocking of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 without any abnormal power supply;

[0048] 6. Compared with the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204, which all adopt interference-locked hydraulic cylinder scheme, this system saves about 30% of the cost.

[0049] The present invention also provides a vehicle that utilizes the aforementioned exhibition vehicle leveling hydraulic system. The first front outrigger cylinder 201 and the second front outrigger cylinder 202 are symmetrically installed on the front side of the vehicle frame, and the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 are symmetrically installed on the rear side of the vehicle frame. A level is installed in the middle of the rear beam of the vehicle frame, and the level is used to measure the levelness AN of the rear beam.

[0050] In this embodiment, the vehicle uses the aforementioned display vehicle leveling hydraulic system, which reduces deployment costs when the vehicle needs to achieve the display vehicle leveling function. Because the display vehicle leveling hydraulic system has high reliability and low failure rate, it can reduce the number of vehicle maintenance operations and improve the vehicle's survivability.

[0051] The present invention also provides a method for leveling a vehicle during deployment, the method utilizing the aforementioned vehicle, and the method includes a vehicle leveling step and a vehicle retraction step:

[0052] The leveling process for the display vehicle includes:

[0053] S11. Energize the electromagnetic overflow valve 404 and the second electromagnetic reversing valve 405 simultaneously; start the quantitative gear pump 401 to build up pressure, and unlock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 simultaneously.

[0054] S12. Energize the proportional relief valve 305; start the variable displacement piston pump 301 to enter the remote control pressure regulation constant pressure variable oil supply mode; simultaneously energize the first multi-way valve 205 and the second multi-way valve 206 to reverse direction, the hydraulic oil pumped by the variable displacement piston pump 301 is pumped into the positive chambers of the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 respectively, and the hydraulic oil in the reverse chambers of the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 flows back to the oil tank 100; when all the wheels of the vehicle leave the ground, de-energize the first multi-way valve 205 to return to the neutral position;

[0055] S13. Determine whether the vehicle's levelness AN is within the specified threshold based on the level gauge. If yes, no leveling is performed. If no, continue pumping hydraulic oil into the positive chamber of the first rear outrigger cylinder 203 or the second rear outrigger cylinder 204 with the second multi-way valve 206 in the working link until the levelness AN measured by the level gauge is within the specified threshold. Then, de-energize the second multi-way valve 206 to return it to the neutral position and shut down the variable piston pump 301.

[0056] S14. De-energize the electromagnetic overflow valve 404 and the second electromagnetic reversing valve 405 simultaneously, shut down the quantitative gear pump 401, unload the unlocking oil circuit 4, and lock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204.

[0057] The vehicle retrieval process includes:

[0058] S21. Energize the proportional relief valve 305 to start the variable displacement piston pump 301 and enter the remote control pressure regulation constant pressure variable oil supply mode; energize the second multi-way valve 206 to reverse the direction, and pump hydraulic oil into the positive chamber of the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 for pressure replenishment. When the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 reach the preset pressure, de-energize the second multi-way valve 206 to return to the neutral position.

[0059] S22. Energize the electromagnetic overflow valve 404 and the second electromagnetic reversing valve 405 simultaneously; start the quantitative gear pump 401 to build up pressure, and unlock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204 simultaneously.

[0060] S23. Simultaneously energize the first multi-way valve 205 and the second multi-way valve 206 to reverse their directions. The hydraulic oil pumped by the variable displacement piston pump 301 is pumped into the reverse chambers of the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203, and the second rear outrigger cylinder 204, respectively. The hydraulic oil in the positive chambers of the first front outrigger cylinder 201, the second front outrigger cylinder 202, the first rear outrigger cylinder 203, and the second rear outrigger cylinder 204 flows back to the oil tank 100. When all the wheels of the vehicle are in contact with the ground, simultaneously de-energize the first multi-way valve 205 and the second multi-way valve 206 to return to the neutral position and shut down the variable displacement piston pump 301.

[0061] S24. De-energize the electromagnetic overflow valve 404 and the second electromagnetic directional valve 405 simultaneously, shut down the quantitative gear pump 401, unload the unlocking oil circuit 4, and lock the first rear outrigger cylinder 203 and the second rear outrigger cylinder 204.

[0062] In this embodiment, a method for leveling a vehicle is provided. This method has fewer control steps and can be controlled synchronously. It adopts a method of leveling by adjusting the hydraulic cylinder of the rear outrigger to extend a shorter length. This method can quickly achieve the leveling of the vehicle's rear beam, controlling the leveling time of the rear beam on a horizontal road to within 25 seconds and the leveling time of the rear beam on a sloping road to within 40 seconds.

[0063] In one embodiment of the present invention, when the proportional relief valve 305 is normal, the first electromagnetic reversing valve 304 is turned on, and the variable piston pump 301 is in the remote control pressure regulating constant pressure variable oil supply mode; when the proportional relief valve 305 is stuck in the large opening, the first electromagnetic reversing valve 304 is turned off, and the variable piston pump 301 changes from the remote control pressure regulating constant pressure variable oil supply mode to the pressure cut-off constant pressure variable oil supply mode.

[0064] In this embodiment, the problem that the variable displacement piston pump 301 cannot output high-pressure hydraulic oil when the proportional relief valve 305 is stuck in the large opening is solved, thereby improving the reliability of the hydraulic system.

[0065] In one embodiment of the present invention, in S13, if the extension length of the first rear outrigger cylinder 203 or the second rear outrigger cylinder 204 exceeds a set length and the levelness AN measured by the level instrument is still not within the specified threshold, then the variable displacement piston pump 301 is shut down and an alarm is triggered. The aforementioned set length is the maximum extension amount of the first rear outrigger cylinder 203 or the second rear outrigger cylinder 204, which is set according to the cylinder's own stroke.

[0066] In this embodiment, a control step is specifically provided to prevent abnormalities from occurring during the tail beam leveling process. This step can prevent the first rear outrigger cylinder 203 or the second rear outrigger cylinder 204 from over-operating, avoid safety accidents, and improve the safety and stability of the hydraulic system.

[0067] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and simple improvements made on the substantive content of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic system for leveling a display vehicle, characterized in that: The system includes an oil tank (100) and a leveling oil circuit (200), an oil supply circuit (300), and an unlocking oil circuit (400) connected to the oil tank (100). The leveling oil circuit (200) includes a first front outrigger cylinder (201), a second front outrigger cylinder (202), a first rear outrigger cylinder (203), and a second rear outrigger cylinder (204). The first front outrigger cylinder (201) and the second front outrigger cylinder (202) are both double-acting cylinders. The first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) are both double-acting cylinders. An interference-fit internal locking type hydraulic cylinder, wherein the oil supply circuit (300) includes a variable displacement piston pump (301), the oil inlet of the variable displacement piston pump (301) is connected to the oil tank (100), and the oil outlet of the variable displacement piston pump (301) is connected to the first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204), respectively. The first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204) are connected by a return oil circuit. The pipe is connected to the oil tank (100). The unlocking oil circuit (400) includes a fixed displacement gear pump (401). The oil inlet of the fixed displacement gear pump (401) is connected to the oil tank (100), and the oil outlet of the fixed displacement gear pump (401) is connected to the unlocking chambers of the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) respectively. The oil supply circuit (300) also includes a first high-pressure oil filter (302), a first one-way valve (303), a first solenoid directional valve (304), and a proportional relief valve (305). The first solenoid directional valve (304) and the proportional relief valve (305) are connected to the oil tank (100). The unlocking oil circuit (400) includes a fixed displacement gear pump (401). The oil inlet of the fixed displacement gear pump (401) is connected to the unlocking chambers of the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) respectively. The oil supply circuit (300) also includes a first high-pressure oil filter (302), a first one-way valve (303), a first solenoid directional valve (304), and a proportional relief valve (305). For example, the relief valve (305) is installed sequentially on the bypass pressure building oil pipe (306) between the oil outlet of the variable piston pump (301) and the oil tank (100) according to the flow direction of the hydraulic oil. When the proportional relief valve (305) is normal, the first solenoid directional valve (304) is turned on, and the variable piston pump (301) is in the remote control pressure regulating constant pressure variable oil supply mode. When the proportional relief valve (305) is stuck in the large opening, the first solenoid directional valve (304) is turned off, and the variable piston pump (301) changes from the remote control pressure regulating constant pressure variable oil supply mode to the pressure cut-off constant pressure variable oil supply mode.

2. The hydraulic system for leveling a display vehicle according to claim 1, characterized in that: The leveling oil circuit (200) of the exhibition vehicle also includes a first multi-way valve (205) and a second multi-way valve (206). Both the first multi-way valve (205) and the second multi-way valve (206) are double-position three-position solenoid directional valves with emergency handles. The first two outlets of the first multi-way valve (205) are connected to the positive and negative cavities of the first front outrigger cylinder (201) through the first positive cavity oil pipe (207) and the first negative cavity oil pipe (208). The second two outlets of the first multi-way valve (205) are connected to the positive and negative cavities of the second front outrigger cylinder (202) through the second positive cavity oil pipe (209) and the second negative cavity oil pipe (210). The first two outlets of the second multi-way valve (206) are connected to the positive and negative cavities of the second front outrigger cylinder (202) through the second positive cavity oil pipe (209) and the second negative cavity oil pipe (210). The oil port is connected to the positive and negative cavities of the first rear outrigger cylinder (203) via the third positive cavity oil pipe (211) and the third negative cavity oil pipe (212). The two oil outlets of the second section of the second multi-way valve (206) are connected to the positive and negative cavities of the second rear outrigger cylinder (204) via the fourth positive cavity oil pipe (213) and the fourth negative cavity oil pipe (214). The first and second inlet ports of the first multi-way valve (205) and the second multi-way valve (206) are connected to the outlet port of the variable piston pump (301) via the outlet pipe (215). The first and second return ports of the first multi-way valve (205) and the second multi-way valve (206) are connected to the oil tank (100) via the return pipe (216).

3. The hydraulic system for leveling a display vehicle according to claim 2, characterized in that: A second check valve (217) and a third check valve (218) are installed sequentially on the first positive cavity oil pipe (207) according to the flow direction of the hydraulic oil. A fourth check valve (219) is installed on the first negative cavity oil pipe (208). The hydraulic control ports of the second check valve (217) and the third check valve (218) are connected to the oil inlet of the fourth check valve (219). The hydraulic control port of the fourth check valve (219) is connected to the oil inlet of the second check valve (217). The second positive cavity oil pipe (209) is equipped with a fifth check valve (220) and a sixth check valve (221) in sequence according to the flow direction of hydraulic oil. The second negative cavity oil pipe (210) is equipped with a seventh check valve (222). The hydraulic control ports of the fifth check valve (220) and the sixth check valve (221) are connected to the oil inlet of the seventh check valve (222). The hydraulic control port of the seventh check valve (222) is connected to the oil inlet of the fifth check valve (220).

4. The hydraulic system for leveling a display vehicle according to claim 3, characterized in that: The leveling oil circuit (200) of the exhibition vehicle also includes a first safety relief valve (223) and a second safety relief valve (224). The first safety relief valve (223) is connected in parallel with the fourth check valve (219), and the second safety relief valve (224) is connected in parallel with the seventh check valve (222).

5. The hydraulic system for leveling a display vehicle according to claim 4, characterized in that: The first high-pressure oil filter (302) and the first one-way valve (303) are installed on the oil outlet pipe (215) in sequence according to the flow direction of the hydraulic oil.

6. The hydraulic system for leveling a display vehicle according to claim 5, characterized in that: The unlocking oil circuit (400) also includes a second high-pressure oil filter (402), an eighth check valve (403), an electromagnetic relief valve (404), and a second electromagnetic directional valve (405). The inlet of the second high-pressure oil filter (402) is connected to the outlet of the fixed displacement gear pump (401), and the outlet of the second high-pressure oil filter (402) is connected to the inlet of the eighth check valve (403). The outlet of the eighth check valve (403) is connected to the inlet of the electromagnetic relief valve (404) through a first oil pipe (406). The outlet of the electromagnetic relief valve (404) is connected to the oil tank (100) through a second oil pipe (407). The inlet of the second electromagnetic directional valve (405) is connected to the first oil pipe through a third oil pipe (408). (406) The return port of the second electromagnetic reversing valve (405) is connected to the second oil pipe (407) through the fourth oil pipe (409). The outlet port of the second electromagnetic reversing valve (405) is connected to the unlocking chamber of the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) through the fifth oil pipe (410). When the electromagnetic overflow valve (404) and the second electromagnetic reversing valve (405) are energized at the same time, the quantitative gear pump (401) builds pressure and controls the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) to unlock. When the electromagnetic overflow valve (404) and the second electromagnetic reversing valve (405) are de-energized at the same time, the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) are locked.

7. A vehicle that utilizes the exhibition vehicle leveling hydraulic system of claim 6, characterized in that, The first front outrigger cylinder (201) and the second front outrigger cylinder (202) are symmetrically installed on the front side of the vehicle frame, and the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) are symmetrically installed on the rear side of the vehicle frame. A level is installed in the middle of the rear beam of the vehicle frame, and the level is used to measure the levelness AN of the rear beam.

8. A method for leveling a vehicle during exhibition, the method utilizing the vehicle described in claim 7, characterized in that: The method includes a vehicle leveling step and a vehicle retraction step: The vehicle leveling process includes: S11. Energize the electromagnetic overflow valve (404) and the second electromagnetic reversing valve (405) simultaneously; start the quantitative gear pump (401) to build up pressure, and unlock the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) simultaneously. S12. Energize the proportional relief valve (305); start the variable piston pump (301) to enter the remote control pressure regulation constant pressure variable oil supply mode; simultaneously energize the first multi-way valve (205) and the second multi-way valve (206) to reverse direction, and pump the hydraulic oil pumped by the variable piston pump (301) into the positive chambers of the first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204), respectively, and the hydraulic oil in the reverse chambers of the first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204) flows back to the oil tank (100); when all the wheels of the vehicle leave the ground, de-energize the first multi-way valve (205) to return to the neutral position; S13. Determine whether the vehicle's levelness AN is within the specified threshold based on the level gauge. If yes, no leveling is performed. If no, continue to pump hydraulic oil into the positive chamber of the first rear outrigger cylinder (203) or the second rear outrigger cylinder (204) with the second multi-way valve (206) in the working position until the levelness AN measured by the level gauge is within the specified threshold. Then, de-energize the second multi-way valve (206) to return it to the neutral position and shut down the variable piston pump (301). S14. De-energize the electromagnetic overflow valve (404) and the second electromagnetic directional valve (405) simultaneously, and shut down the quantitative gear pump (401), unload the unlocking oil circuit (400), and lock the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204). The vehicle recall process includes: S21. Energize the proportional relief valve (305) to start the variable piston pump (301) and enter the remote control pressure regulation constant pressure variable oil supply mode; energize the second multi-way valve (206) to reverse the direction, and pump the hydraulic oil into the positive chamber of the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) to replenish the pressure. When the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) reach the preset pressure, de-energize the second multi-way valve (206) to return to the neutral position. S22, energize the electromagnetic overflow valve (404) and the second electromagnetic reversing valve (405) simultaneously; start the quantitative gear pump (401) to build up pressure, and unlock the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204) simultaneously; S23. Simultaneously energize the first multi-way valve (205) and the second multi-way valve (206) to reverse direction. The hydraulic oil pumped by the variable piston pump (301) is pumped into the reverse chambers of the first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204), respectively. The hydraulic oil in the positive chambers of the first front outrigger cylinder (201), the second front outrigger cylinder (202), the first rear outrigger cylinder (203), and the second rear outrigger cylinder (204) flows back to the oil tank (100). When all the wheels of the vehicle are in contact with the ground, simultaneously de-energize the first multi-way valve (205) and the second multi-way valve (206) to return to the neutral position and shut down the variable piston pump (301). S24. De-energize the electromagnetic overflow valve (404) and the second electromagnetic directional valve (405) simultaneously, shut down the quantitative gear pump (401), unload the unlocking oil circuit (400), and lock the first rear outrigger cylinder (203) and the second rear outrigger cylinder (204). When the proportional relief valve (305) is normal, the first solenoid directional valve (304) is turned on, and the variable piston pump (301) is in the remote control pressure regulation constant pressure variable oil supply mode; when the proportional relief valve (305) is stuck in the large opening, the first solenoid directional valve (304) is turned off, and the variable piston pump (301) changes from the remote control pressure regulation constant pressure variable oil supply mode to the pressure cut-off constant pressure variable oil supply mode.

9. A method for leveling a vehicle during exhibition according to claim 8, characterized in that: In S13, if the extension length of the first rear outrigger cylinder (203) or the second rear outrigger cylinder (204) exceeds the set length and the levelness AN measured by the level instrument is still not within the specified threshold, the variable piston pump (301) will be shut down and an alarm will be triggered.

Images