Hydraulic system and vehicle

Abstract

The utility model relates to the technical field of hydraulic pressure, and discloses a hydraulic system and a vehicle. An inlet of the hydraulic pump is communicated with the oil storage space; an outlet of the proportional valve is communicated with the oil storage space; the electromagnetic valve is provided with a first channel and a second channel, the first channel is communicated with an outlet of the hydraulic pump, the second channel is communicated with an inlet of the proportional valve, the electromagnetic valve can be switched between a first access state and a second access state, and when the electromagnetic valve is in the first access state, the first channel is communicated and the second channel is disconnected; when the electromagnetic valve is in the second access state, the first channel is disconnected and the second channel is communicated; the first one-way valve is arranged in the first channel; the lifting oil cylinder is communicated with the first channel and the second channel; and the controller is electrically connected with the proportional valve and the electromagnetic valve. According to the hydraulic system, the descending speed can be linearly adjusted, and the descending control precision is high.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology, specifically to a hydraulic system and a vehicle. Background Technology

[0002] Forklifts, as essential logistics equipment used for unloading, loading, and stacking, play a vital role in the modern logistics industry. The hydraulic system, as one of the core technologies of forklifts, should ensure efficient, accurate, and safe operation.

[0003] The hydraulic system in the related technology uses a combination of solenoid valves, throttle valves and check valves. The check valves and solenoid valves work together to control the lifting and holding of the goods, while the throttle valves and solenoid valves work together to control the descent speed of the goods. The descent speed cannot be adjusted, resulting in low control precision. Utility Model Content

[0004] In view of this, the present invention provides a hydraulic system and vehicle to solve the problems of the inability to adjust the cargo descent speed and low control precision.

[0005] In a first aspect, this utility model provides a hydraulic system, comprising: an oil reservoir with an oil storage space; a hydraulic pump, the inlet of which is connected to the oil storage space; a proportional valve with its outlet connected to the oil storage space; a solenoid valve with a first channel and a second channel, the first channel being connected to the outlet of the hydraulic pump and the second channel being connected to the inlet of the proportional valve, the solenoid valve being switchable between a first-path state and a second-path state, wherein when the solenoid valve is in the first-path state, the first channel is connected and the second channel is disconnected, and when the solenoid valve is in the second-path state, the first channel is disconnected and the second channel is connected; a first check valve disposed in the first channel; a lifting cylinder connected to both the first and second channels; and a controller electrically connected to the proportional valve and the solenoid valve.

[0006] Beneficial Effects: The hydraulic system of this embodiment achieves dual stop and pressure maintenance through the first check valve and proportional valve within the solenoid valve. Even if one of the solenoid valve or proportional valve fails, the other can still ensure the cargo stops at the designated position, preventing cargo stalling due to solenoid or proportional valve malfunction. This results in a low failure rate and improved safety. Because the proportional valve 300 has a pressure compensation function, the flow rate through it is unaffected by the weight of the cargo. That is, the cargo's descent speed is only related to the controller's control signal. Furthermore, the opening degree of the proportional valve changes linearly, therefore the oil velocity and flow rate also change linearly, enabling linearly adjustable descent speed of the lifting cylinder and high control precision.

[0007] In one alternative embodiment, the hydraulic system further includes an overflow valve connected between the hydraulic pump and the oil reservoir.

[0008] Beneficial effects: It can limit the maximum pressure of the hydraulic system's flow path, preventing dangerous situations caused by excessive pressure in the lifting cylinder due to cargo overload.

[0009] In one alternative embodiment, the hydraulic system further includes a shut-off valve connected between the lifting cylinder and the oil storage space.

[0010] Beneficial effects: When the solenoid valve or proportional valve is damaged, the oil in the lifting cylinder cannot flow back to the oil storage space through the solenoid valve or proportional valve. At this time, the shut-off valve can be opened to allow the oil in the lifting cylinder to flow back to the oil storage space through the shut-off valve, thereby lowering the lifting cylinder and thus lowering the cargo.

[0011] In one alternative embodiment, the hydraulic system further includes an explosion-proof valve connected between the solenoid valve and the lifting cylinder.

[0012] Beneficial effects: When the pipeline or component of the hydraulic system is damaged or burst, the explosion-proof valve can be closed to prevent the oil in the lifting cylinder from dropping rapidly. The lifting cylinder can maintain its current position or descend slowly, thereby preventing the cargo from falling rapidly and causing danger.

[0013] In one alternative embodiment, the hydraulic pump includes a gear pump; the hydraulic system further includes a drive motor, which is drivenly connected to the gear pump, and the controller is electrically connected to the drive motor.

[0014] Beneficial effects: The controller can output control signals to the drive motor to adjust the speed of the drive motor. The speed of the gear pump will also change with the speed of the drive motor, thereby changing the input flow of the hydraulic system and adjusting the lifting speed of the lifting cylinder.

[0015] In one alternative embodiment, the hydraulic system further includes a pressure oil filter connected between the solenoid valve and the lifting cylinder.

[0016] Beneficial effects: The hydraulic filter can filter out the iron filings generated by the wear of the gear pump during operation, preventing the iron filings from entering the lifting cylinder and affecting its normal operation, reducing the probability of damage to the lifting cylinder, and extending its service life.

[0017] In one alternative embodiment, the hydraulic system further includes a second check valve connected between the solenoid valve and the hydraulic pump.

[0018] Beneficial effect: Prevents gears inside the gear pump from reversing and dragging the drive motor in reverse, thereby preventing damage to the gear pump and drive motor.

[0019] In one alternative embodiment, the hydraulic system further includes an oil suction filter connected between the oil storage space and the hydraulic pump.

[0020] Beneficial effects: The suction filter can filter the oil that is about to flow in, such as filtering out particulate impurities in the oil, preventing particulate impurities in the oil from entering the hydraulic pump, solenoid valve, lifting cylinder and other components in the hydraulic system, thereby reducing the probability of damage to the components in the hydraulic system.

[0021] Secondly, this utility model also provides a vehicle, comprising: a body: a hydraulic system according to the first aspect, mounted on the body.

[0022] Beneficial effects: The vehicle of this utility model embodiment, utilizing the above-mentioned hydraulic system, can achieve linear adjustment of the cargo descent speed, thereby improving control accuracy.

[0023] In one alternative embodiment, the vehicle body is equipped with wheels; the hydraulic system further includes a pressure cylinder communicating with the first channel and the second channel, and being detachably in contact with the wheels.

[0024] Beneficial effects: It can improve the traction of the wheels and reduce the risk of accidents caused by wheel slippage. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the hydraulic system according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Hydraulic system; 100. Oil reservoir; 110. Oil reservoir space; 200. Hydraulic pump; 210. Drive motor; 300. Proportional valve; 400. Solenoid valve; 410. First check valve; 510. Lifting cylinder; 511. Explosion-proof valve; 520. Pressure cylinder; 600. Relief valve; 700. Shut-off valve; 810. Pressure oil filter; 820. Suction oil filter; 900. Second check valve. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0031] In the description of this utility model, "a plurality of" means two or more. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0033] The following is combined with Figure 1 The following describes embodiments of the present invention.

[0034] According to an embodiment of the present invention, a hydraulic system 1 is provided, including an oil reservoir 100, a hydraulic pump 200, a proportional valve 300, a solenoid valve 400, a first check valve 410, a lifting cylinder 510, and a controller. The oil reservoir 100 can be an oil tank, and the proportional valve 300 can have a pressure-holding function.

[0035] The oil reservoir 100 has an oil storage space 110, which stores hydraulic oil. The hydraulic oil serves to settle impurities, dissipate heat, and provide pressure. The inlet of the hydraulic pump 200 is connected to the oil storage space 110, and the outlet of the proportional valve 300 is also connected to the oil storage space 110. The solenoid valve 400 has a first channel and a second channel. The first channel is connected to the outlet of the hydraulic pump 200, and the second channel is connected to the inlet of the proportional valve 300. The solenoid valve 400 can switch between a first-path state and a second-path state. When the solenoid valve 400 is in the first-path state, the first channel is open and the second channel is closed; when the solenoid valve 400 is in the second-path state, the first channel is closed and the second channel is open. The lifting cylinder 510 is connected to both the first and second channels. The controller is electrically connected to the proportional valve 300 and the solenoid valve 400.

[0036] For example, there can be one or more lifting cylinders 510. The size and model of the lifting cylinders 510 can be the same. Multiple lifting cylinders 510 can lift and lower synchronously. For example, one lifting cylinder 510 supports the left side of the goods, and another lifting cylinder 510 supports the left side of the goods. The supporting force on the goods is more even, which helps to improve the stability of the goods movement.

[0037] In addition, the solenoid valve 400 can be a two-position two-way valve, that is, the first channel and the second channel share the same inlet and outlet; or the solenoid valve 400 can be a two-position three-way valve, that is, the first channel and the second channel share the same outlet, and the inlet of the first channel and the inlet of the second channel can be different.

[0038] Specifically, when the lifting cylinder 510 needs to be raised (i.e. when the goods need to be raised), the solenoid valve 400 is in the first passage state, the hydraulic pump 200 pumps oil from the oil storage space 110, and the oil flows through the hydraulic pump 200 and the first passage to the lifting cylinder 510 so that the lifting cylinder 510 is raised.

[0039] When the lifting cylinder 510 needs to be held in the current position (i.e., when the cargo needs to be held in the current position), the solenoid valve 400 is in the first passage state, and the hydraulic pump 200 can be inactive. The first check valve 410 inside the solenoid valve 400 can prevent the backflow of oil in the lifting cylinder 510, providing a pressure holding function. The proportional valve 300 can also provide a pressure holding function to achieve dual stop pressure holding. If one of the solenoid valve 400 and the proportional valve 300 fails, the other can still ensure that the cargo stops in the designated position, preventing the cargo from stalling due to the failure of the solenoid valve 400 or the proportional valve 300. The failure rate is low, and safety is improved.

[0040] When the lifting cylinder 510 needs to be lowered (i.e. when the cargo needs to be lowered), the solenoid valve 400 is in the second passage state. The oil in the lifting cylinder 510 flows to the oil storage space 110 through the second passage and the proportional valve 300, so that the lifting cylinder 510 is lowered. At this time, the flow rate and volume of the oil can be adjusted by adjusting the opening of the proportional valve 300 by the controller, thereby adjusting the lowering speed of the lifting cylinder 510 and achieving the purpose of adjusting the lowering speed of the cargo.

[0041] Because the proportional valve 300 has a pressure compensation function, the flow rate through the proportional valve 300 is not affected by the weight of the cargo. That is, the descent speed of the cargo is only related to the control signal of the controller. Furthermore, the opening degree of the proportional valve 300 changes linearly, so the flow rate and flow rate of the oil also change linearly. This enables the descent speed of the lifting cylinder 510 to be linearly adjustable, resulting in high control precision.

[0042] Furthermore, integrating the first check valve 410 into the solenoid valve 400 reduces the number of parts, simplifies the control logic, reduces the risk of failure, and facilitates assembly.

[0043] like Figure 1 As shown, in the technical solution of this embodiment, the hydraulic system 1 further includes a relief valve 600, which is connected between the hydraulic pump 200 and the oil storage space 110. Specifically, the inlet of the relief valve 600 is connected to the outlet of the hydraulic pump 200 and the solenoid valve 400, and the outlet of the relief valve 600 is connected to the oil storage space 110.

[0044] When the pressure in the flow path between the hydraulic pump 200 and the solenoid valve 400 is lower than the preset pressure, the relief valve 600 closes, and the oil flowing out of the hydraulic pump 200 can flow to the lifting cylinder 510 through the solenoid valve 400, ensuring the lifting efficiency of the lifting cylinder 510.

[0045] When the pressure in the flow path between the hydraulic pump 200 and the solenoid valve 400 reaches the preset pressure, the relief valve 600 opens. Part of the oil flowing out of the hydraulic pump 200 flows back to the oil storage space 110 through the relief valve 600, and the other part of the oil flowing out of the hydraulic pump 200 flows to the lifting cylinder 510 through the solenoid valve 400. This can avoid increasing the pressure in the flow path between the hydraulic pump 200 and the solenoid valve 400.

[0046] By setting the relief valve 600, the maximum pressure of the flow path between the hydraulic pump 200 and the solenoid valve 400 can be limited, thereby limiting the highest pressure of the flow path of the hydraulic system 1 and preventing the lifting cylinder 510 from being overloaded and causing excessive pressure, which could lead to danger.

[0047] like Figure 1As shown, in this embodiment, the hydraulic system 1 further includes a shut-off valve 700, which is connected between the lifting cylinder 510 and the oil storage space 110. Specifically, the opening of the shut-off valve 700 is connected to the lifting cylinder 510, and the outlet of the shut-off valve 700 is connected to the oil storage space 110.

[0048] Specifically, the shut-off valve 700 is normally closed. When the solenoid valve 400 or the proportional valve 300 is damaged, the oil in the lifting cylinder 510 cannot flow back to the oil storage space 110 through the solenoid valve 400 or the proportional valve 300. At this time, the shut-off valve 700 can be opened so that the oil in the lifting cylinder 510 can flow back to the oil storage space 110 through the shut-off valve 700, thereby lowering the lifting cylinder 510 and thus lowering the cargo.

[0049] The shut-off valve 700 can be manually switched on and off by the operator, or it can be connected to a controller. The controller can obtain the working status of the solenoid valve 400 and the proportional valve 300. When the solenoid valve 400 and the proportional valve 300 are malfunctioning (i.e., they may be damaged), the controller can actively control the shut-off valve 700 to open, or the operator can control the shut-off valve 700 to open through the controller.

[0050] like Figure 1 As shown, in this embodiment, the hydraulic system 1 further includes an explosion-proof valve 511, which is connected between the solenoid valve 400 and the lifting cylinder 510. Specifically, the inlet of the explosion-proof valve 511 is connected to both the first and second channels, and the outlet of the explosion-proof valve 511 is connected to the lifting cylinder 510. That is, the hydraulic fluid flows from the first channel of the solenoid valve 400 into the explosion-proof valve 511, and then into the lifting cylinder 510.

[0051] Specifically, the explosion-proof valve 511 can be in the normally open state. When the pipeline of the hydraulic system 1 is damaged or burst, or when the components are damaged or burst, the oil in the hydraulic system 1 will leak through the damaged or burst point, causing the oil in the hydraulic system 1 to drop rapidly. At this time, the explosion-proof valve 511 can be closed to prevent the oil in the lifting cylinder 510 from dropping rapidly. The lifting cylinder 510 can remain in the current position or drop slowly, thereby preventing the cargo from dropping rapidly and causing danger.

[0052] Among them, the explosion-proof valve 511 can be manually switched on and off by the operator, or the explosion-proof valve 511 can be connected to the controller. The controller can obtain the oil pressure status of the hydraulic system 1. When the oil pressure status of the hydraulic system 1 is abnormal (i.e., when oil leakage may occur), the controller can actively control the shut-off valve 700 to open, or the operator can control the shut-off valve 700 to open through the explosion-proof valve 511.

[0053] Alternatively, there can be multiple explosion-proof valves 511, with each explosion-proof valve 511 connected to a corresponding lifting cylinder 510 to ensure that the oil pressure in each lifting cylinder 510 does not drop rapidly due to oil leakage, thus ensuring high safety. Or, there can be a single explosion-proof valve 511, with one of the multiple lifting cylinders 510 connected to it, ensuring that the oil pressure in at least one lifting cylinder 510 does not drop rapidly due to oil leakage. This method also reduces the number of explosion-proof valves 511, lowering costs. Furthermore, there can be a single explosion-proof valve 511, with multiple lifting cylinders 510 connected to it, ensuring that the oil pressure in each lifting cylinder 510 does not drop rapidly due to oil leakage. This method also reduces the number of explosion-proof valves 511, further lowering costs.

[0054] like Figure 1 As shown, in this embodiment, the hydraulic pump 200 includes a gear pump, and the hydraulic system 1 also includes a drive motor 210. The drive motor 210 is connected to the gear pump via a transmission connection, and the controller is electrically connected to the drive motor 210. The drive motor 210 can be a DC drive motor, and the gear pump can be connected to the drive motor 210 via a coupling. The drive motor 210 provides a power source for the gear pump.

[0055] The controller can output control signals to the drive motor 210 to adjust the speed of the drive motor 210. The speed of the gear pump will also change with the speed of the drive motor 210, thereby changing the input flow of the hydraulic system 1 and adjusting the lifting speed of the lifting cylinder 510.

[0056] Furthermore, the hydraulic system 1 also includes a second check valve 900, which is connected between the solenoid valve 400 and the hydraulic pump 200. Specifically, the inlet of the second check valve 900 is connected to the outlet of the hydraulic pump 200, and the outlet of the second check valve 900 is connected to the first channel. The hydraulic fluid from the outlet of the hydraulic pump 200 can flow to the solenoid valve 400 through the second check valve 900, but the hydraulic fluid from the solenoid valve 400 cannot flow to the hydraulic pump 200 through the second check valve 900.

[0057] In this way, when the solenoid valve 400 switches to the second channel state, after the oil in the lifting cylinder 510 flows to the solenoid valve 400, it prevents the oil in the second channel from flowing back to the gear pump, thus avoiding the gears in the gear pump from reversing and dragging the drive motor 210, thereby preventing damage to the gear pump and the drive motor 210. At the same time, the second check valve 900 can ensure that the oil in the lifting cylinder 510 flows into the proportional valve 300 through the solenoid valve 400, so as to achieve accurate and controllable lowering speed of the lifting cylinder 510, thereby ensuring accurate and controllable lowering speed of the goods.

[0058] like Figure 1As shown, in this embodiment, the hydraulic system 1 further includes a hydraulic filter 810, which is connected between the solenoid valve 400 and the lifting cylinder 510. Specifically, the inlet of the hydraulic filter 810 is connected to the first channel, and the outlet of the hydraulic filter 810 is connected to the lifting cylinder 510.

[0059] In other words, after the hydraulic pump 200 and solenoid valve 400 pass through the hydraulic filter 810 before flowing into the lifting cylinder 510, all the hydraulic fluid entering the lifting cylinder 510 is filtered by the hydraulic filter 810. In this way, the hydraulic filter 810 can filter out the iron filings generated by the wear of the gear pump during operation, preventing these iron filings from entering the lifting cylinder 510 and affecting its normal operation, reducing the probability of damage to the lifting cylinder 510, extending its service life, and preventing iron filings from continuing to circulate within the hydraulic system 1 and entering other components of the hydraulic system 1, thus reducing the overall probability of damage to the hydraulic system 1 and ensuring its reliable operation.

[0060] like Figure 1 As shown in the technical solution of this embodiment, the hydraulic system 1 further includes a suction filter 820, which is connected between the oil storage space 110 and the hydraulic pump 200. Specifically, the inlet of the suction filter 820 is connected to the oil storage space 110, and the outlet of the suction filter 820 is connected to the inlet of the hydraulic pump 200. All oil entering the hydraulic pump 200 from the oil storage space 110 must pass through the suction filter 820. The suction filter 820 can filter the oil to be flowing in, for example, filtering out particulate impurities in the oil, preventing particulate impurities from entering the hydraulic pump 200, solenoid valve 400, lifting cylinder 510, and other components in the hydraulic system 1, thereby reducing the probability of damage to components in the hydraulic system 1, extending the service life of the hydraulic system 1, and reducing the frequency of maintenance of the hydraulic system 1.

[0061] According to an embodiment of this utility model, another aspect provides a vehicle, which includes a vehicle body and the aforementioned hydraulic system 1, the hydraulic system 1 being mounted on the vehicle body. The vehicle can be a forklift, such as a stacker truck. Of course, the vehicle can also be other vehicles that require the lifting function of the hydraulic system 1, such as a dump truck.

[0062] The vehicle of this utility model embodiment, utilizing the aforementioned hydraulic system 1, can achieve linear adjustment of the cargo descent speed, thereby improving control accuracy.

[0063] like Figure 1 As shown, in the technical solution of this embodiment, the vehicle body is equipped with wheels, and the hydraulic system 1 also includes a pressure cylinder 520, which is connected to the first channel and the second channel, and the pressure cylinder 520 is in separable contact with the wheel.

[0064] In some cases, vehicles may travel on slippery surfaces, and at higher speeds, there is a risk of wheel slippage. By incorporating a hydraulic cylinder 520, the traction of the wheels can be improved, reducing the risk of accidents caused by wheel slippage.

[0065] The working process of hydraulic system 1 is described below with reference to the accompanying drawings:

[0066] 1) Cargo lifting:

[0067] First, the controller outputs a control signal to control the drive motor 210 to rotate. At this time, the solenoid valve 400 is in the first passage state. The drive motor 210 drives the hydraulic pump 200 to rotate. The hydraulic oil enters the hydraulic pump 200 through the suction filter 820 and flows through the second check valve 900 and the first check valve 410 in the first passage.

[0068] Then, after passing through the pressure oil filter 810, part of the hydraulic oil enters the pressure cylinder 520 to pressurize the wheels, and the other part of the hydraulic oil flows through the explosion-proof valve 511 and flows to at least one lifting cylinder 510. The lifting cylinder 510 rises to lift. At this time, the controller outputs a control signal to control the speed of the drive motor 210 to adjust the flow rate of the hydraulic pump 200 into the hydraulic system 1, thereby controlling the lifting speed of the goods.

[0069] Finally, when the cargo reaches any designated height within the travel range and needs to stop, the controller outputs a control signal to control the drive motor 210 to stop rotating. At this time, the first check valve 410 of the solenoid valve 400 works, and the reverse shut-off hydraulic oil achieves the pressure holding effect, locking the cargo in the designated position. During the cargo lifting process, the proportional valve 300 and the shut-off valve 700 do not work and are in the closed state.

[0070] 2) Cargo descending:

[0071] First, when the goods need to be lowered from a height, the drive motor 210 does not work, the solenoid valve 400 switches to the second channel state, and the controller outputs a control signal to control the proportional valve 300 to open. Under the gravity of the goods and the gantry, the hydraulic oil in the lifting cylinder 510 flows back to the oil tank through the explosion-proof valve 511, the pressure oil filter 810, the second channel of the solenoid valve 400 and the proportional valve 300, and the goods are lowered.

[0072] Then, when the cargo descends to the predetermined position, the controller outputs a control signal to close the proportional valve 300 and switch the solenoid valve 400 to the first passage device, so that the cargo stops descending and remains at the current position.

[0073] Since the opening degree of the proportional valve 300 is positively correlated with the control signal of the controller, the opening degree of the proportional valve 300 can be continuously adjusted by adjusting the control signal, thereby continuously adjusting the speed of the cargo descent.

[0074] 3) Wheel loading:

[0075] The pressure cylinder 520 is connected in parallel with the lifting cylinder 510. It is connected to the hydraulic oil in the hydraulic system 1 during the lifting, stopping and lowering stages of the cargo. The pressure cylinder 520 applies the pressure of the hydraulic system 1 to the wheels, which can improve the adhesion of the wheels.

[0076] 4) Emergency descent:

[0077] When the solenoid valve 400 or the proportional valve 300 malfunctions or the controller fails to output a control signal, the goods can only rise and cannot descend. In this case, the shut-off valve 700 can be opened manually, and the goods can descend slowly.

[0078] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A hydraulic system, characterized in that, include: An oil storage component (100) is provided with an oil storage space (110); A hydraulic pump (200) is provided, the inlet of which is connected to the oil storage space (110); A proportional valve (300) is provided, the outlet of which is connected to the oil storage space (110); The solenoid valve (400) has a first channel and a second channel. The first channel is connected to the outlet of the hydraulic pump (200), and the second channel is connected to the inlet of the proportional valve (300). The solenoid valve (400) can switch between a first channel state and a second channel state. When the solenoid valve (400) is in the first channel state, the first channel is connected and the second channel is disconnected. When the solenoid valve (400) is in the second channel state, the first channel is disconnected and the second channel is connected. A first check valve (410) is located in the first channel; The lifting cylinder (510) is connected to the first channel and the second channel; The controller is electrically connected to the proportional valve (300) and the solenoid valve (400).

2. The hydraulic system according to claim 1, characterized in that, Also includes: An overflow valve (600) is connected between the hydraulic pump (200) and the oil reservoir (110).

3. The hydraulic system according to claim 1, characterized in that, Also includes: A shut-off valve (700) is connected between the lifting cylinder (510) and the oil storage space (110).

4. The hydraulic system according to claim 1, characterized in that, Also includes: An explosion-proof valve (511) is connected between the solenoid valve (400) and the lifting cylinder (510).

5. The hydraulic system according to claim 1, characterized in that, The hydraulic pump (200) includes a gear pump; The hydraulic system (1) further includes a drive motor (210), which is connected to the gear pump in a transmission manner, and the controller is electrically connected to the drive motor (210).

6. The hydraulic system according to claim 5, characterized in that, Also includes: A hydraulic filter (810) is connected between the solenoid valve (400) and the lifting cylinder (510).

7. The hydraulic system according to claim 5, characterized in that, Also includes: A second check valve (900) is connected between the solenoid valve (400) and the hydraulic pump (200).

8. The hydraulic system according to any one of claims 1-7, characterized in that, Also includes: An oil suction filter (820) is connected between the oil storage space (110) and the hydraulic pump (200).

9. A vehicle, characterized in that, include: Body: The hydraulic system (1) according to any one of claims 1-8 is installed on the vehicle body.

10. The vehicle according to claim 9, characterized in that, The vehicle body is equipped with wheels; The hydraulic system (1) further includes a pressure cylinder (520) that communicates with the first channel and the second channel and is in separable contact with the wheel.

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