Hydraulic system for road surface self-adaption of sweeping roller height of motor sweeper

Abstract

The invention provides a hydraulic system with a sweeping roller height self-adaptive to a road surface of a sweeper, which comprises a sweeping roller hydraulic system part and a sweeping roller lifting hydraulic system part, and a low-pressure oil suction port of the sweeping roller hydraulic system part is communicated with a hydraulic oil tank. The sweeping roller hydraulic system part and the sweeping roller lifting hydraulic system part share a low-pressure oil suction port, and an oil return port T of the sweeping roller hydraulic system part and an oil return port T of the sweeping roller lifting hydraulic system part are combined through a three-way connector and then communicated with an oil inlet of a cooler. An oil outlet of the cooler is communicated with an oil inlet of the oil return filter, and the oil return filter is installed on the top of the hydraulic oil tank. Compared with the prior art, the device has the following beneficial effects that through the arrangement of the sweeping roller hydraulic system part and the sweeping roller lifting hydraulic system part, the problems that the sweeping effect is poor and related mechanisms of a rear sweeping roller are damaged when the sweeping vehicle works on some road surfaces or slopes with large fluctuation are solved.

Description

Technical Field

[0001] The invention discloses a hydraulic system for a sweeping roller of a sweeper to adapt to the road surface height, and belongs to the field of hydraulic systems for road construction machinery. Background Art

[0002] ‌With the rapid development of urbanization, road cleaning and maintenance have become an important part of urban management. It has greatly improved cleaning efficiency and reduced labor costs. When performing cleaning work, the sweeper needs to lower the sweeping roller to contact the ground. The sweeping roller rotates to roll up the garbage on the ground and then transports the garbage into the garbage bin through the inclined scraper. The working environment of the sweeper is different. When working on some undulating roads or slopes, or as the sweeping roller is used for a long time, the roller brush of the sweeping roller will be worn accordingly, which will cause the rear sweeping roller to contact the ground too much or too little, resulting in poor cleaning effect and shortened life of the rear sweeping roller related mechanism. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a hydraulic system for the sweeper's sweeping roller to adapt to the road surface height, aiming to solve the problems of poor cleaning effect and damage to the rear sweeping roller related mechanism when the sweeper is working on some undulating roads or slopes.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A hydraulic system for a sweeper roller with adaptive road surface height comprises a sweeper roller hydraulic system part and a sweeper roller lifting hydraulic system part, the low-pressure oil suction port of the sweeper roller hydraulic system part is connected to a hydraulic oil tank, the sweeper roller hydraulic system part and the sweeper roller lifting hydraulic system part share a low-pressure oil suction port, the return oil port T of the sweeper roller hydraulic system part and the return oil port T of the sweeper roller lifting hydraulic system part are connected to the oil inlet of a cooler after being merged through a three-way joint, the oil outlet of the cooler is connected to the oil inlet of a return oil filter, the return oil filter is installed on the top of the hydraulic oil tank, and the oil outlet of the return oil filter is connected to the hydraulic oil tank.

[0006] Furthermore, the sweeping roller hydraulic system includes an oil suction filter, a sweeping roller gear pump, a sweeping roller pressure gauge, a proportional multi-way valve, a pressure sensor and a sweeping roller motor. The low-pressure oil suction port of the sweeping roller gear pump is connected in series with the oil suction filter and then connected to the hydraulic oil tank. The high-pressure oil port of the sweeping roller gear pump is connected to the oil inlet P of the proportional multi-way valve. The working oil ports A and B of the proportional multi-way valve are respectively connected to the inlet and outlet of the sweeping roller motor.

[0007] Furthermore, a pressure sensor is connected in parallel between the port A of the proportional multi-way valve and the oil inlet of the sweeping roller motor.

[0008] Furthermore, a sweep roller pressure gauge is installed at the high-pressure outlet of the sweep roller gear pump, and the sweep roller pressure gauge is connected in parallel with the proportional multi-way valve.

[0009] Furthermore, the sweeping roller lifting hydraulic system part includes a sweeping roller lifting gear pump, a sweeping roller lifting pressure gauge, a sweeping roller lifting hydraulic valve group part and a sweeping roller lifting actuator. The sweeping roller lifting gear pump and the sweeping roller gear pump form a series pump and share a low-pressure oil suction port. The high-pressure oil outlet of the sweeping roller lifting gear pump is connected to the oil inlet P of the sweeping roller lifting hydraulic valve group part.

[0010] Furthermore, the sweeping roller lifting hydraulic valve group includes a sweeping roller lifting hydraulic valve block, two sweeping roller lifting electromagnetic reversing valves, and the sweeping roller lifting actuator includes a first sweeping roller lifting cylinder and a second sweeping roller lifting cylinder. The A and B ports of the two sweeping roller lifting electromagnetic reversing valves are respectively connected to the rod chamber and rodless chamber oil ports on the first sweeping roller lifting cylinder and the second sweeping roller lifting cylinder through the four oil ports A1, B1, A2, and B2 of the sweeping roller lifting hydraulic valve block.

[0011] Furthermore, two sweeping roller lifting superimposed one-way hydraulic locks and two sweeping roller lifting superimposed double one-way throttle valves are respectively superimposed between the two sweeping roller lifting electromagnetic reversing valves and the sweeping roller lifting hydraulic valve block.

[0012] Furthermore, the sweeping roller lifting hydraulic system also includes a unloading relief valve, the oil inlet of the unloading relief valve is connected in parallel with the oil inlet P of the sweeping roller lifting hydraulic valve group and is connected to the high-pressure oil outlet of the sweeping roller lifting gear pump, and the oil return port of the unloading relief valve is merged with the oil return port T of the sweeping roller lifting hydraulic valve block through a three-way joint.

[0013] Furthermore, a sweeping roller lifting pressure gauge is connected in parallel between the high-pressure oil outlet of the sweeping roller lifting gear pump and the oil inlet P of the sweeping roller lifting hydraulic valve group.

[0014] Furthermore, an air filter and a liquid temperature gauge are installed on the hydraulic oil tank.

[0015] Beneficial effects of the present invention:

[0016] By setting the pressure sensor, the working pressure of the sweeping roller motor can be detected and fed back to the control system. The controller will always judge whether the feedback pressure is within the normal working pressure range. If it exceeds the normal working pressure range, the controller will issue relevant instructions to the sweeping roller lifting actuator to adjust the sweeping roller to maintain it in a normal working state; when the sweeping roller is cleaning on a relatively flat road surface, the normal working pressure of the sweeping roller motor is basically stable at around 100 bar; when the sweeping roller is working on a working road with large undulations or the sweeping roller brush is worn to a certain extent, if the pressure sensor detects that the working pressure of the sweeping roller motor becomes low and is lower than the set minimum adjustment working pressure, the controller will issue a descending instruction to the sweeping roller lifting actuator to lower the sweeping roller, so that the contact area between the sweeping roller and the ground becomes larger, and the sweeping roller motor After reaching the set normal working pressure, the controller stops outputting the descending instruction, and the lowest adjustment working pressure setting value is 60bar; on the contrary, if the pressure sensor detects that the working pressure of the sweeping roller motor becomes higher and is higher than the set maximum adjustment working pressure, the controller will send an ascending instruction to the sweeping roller lifting actuator to lower the sweeping roller, so that the contact area between the sweeping roller and the ground becomes smaller. After the working pressure of the sweeping roller motor reaches the set normal working pressure, the controller stops outputting the ascending instruction, and the highest adjustment working pressure setting value is 130bar; the height of the sweeping roller is adjusted by self-feedback to adapt to the cleaning of different road conditions, and the working state of the sweeping roller brush after wear can be automatically adjusted, eliminating the need for manual adjustment of the height of the sweeping roller brush, ensuring the road cleaning effect, and improving the cleaning efficiency.

[0017] Through the design of the unloading relief valve, the maximum pressure of the sweeping roller lifting hydraulic system can be limited, the safety of the hydraulic system can be protected, and the service life of the hydraulic components can be extended. The set pressure value is 160bar.

[0018] Through the design of the hydraulic cooler, the temperature of the hydraulic oil can be reduced, protecting the components in the hydraulic system and preventing attenuation or failure caused by high temperature, thereby extending their service life, reducing the system failure rate and improving the reliability of the system.

[0019] The design of the return oil filter can filter the particles in the hydraulic oil to a certain extent. Maintaining the cleanliness of the system helps reduce system failures and improve system reliability and overall performance.

[0020] Through the design of the thermometer, the oil height and temperature in the hydraulic system can be monitored to ensure that the volume of hydraulic oil in the hydraulic tank system operates within the appropriate temperature range, thereby extending the service life of the equipment and improving the performance of the system.

[0021] The design of the air filter can prevent particulate contaminants from invading the system through the hydraulic oil tank breathing port and prevent particulate contaminants from mixing in during the refueling process, thereby extending the working cycle and service life of the oil and components and ensuring the normal operation of the hydraulic system. In addition, it can also maintain the pressure in the oil tank balanced with the atmospheric pressure to avoid cavitation in the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic diagram of a hydraulic system for a road sweeper with a sweeping roller that is height-adaptive to the road surface according to the present invention.

[0024] In the figure, 100, sweep roller hydraulic system part; 110, oil suction filter; 120, sweep roller gear pump; 130, sweep roller pressure gauge; 140, proportional multi-way valve; 150, pressure sensor; 160, sweep roller motor; 200, sweep roller lifting hydraulic system part; 210, sweep roller lifting gear pump; 220, unloading relief valve; 230, sweep roller lifting pressure gauge; 240, sweep roller lifting hydraulic valve block; 250, sweep roller lifting electromagnetic reversing valve; 260, sweep roller lifting superimposed one-way hydraulic lock; 270, sweep roller lifting superimposed double one-way throttle valve; 2801, first sweep roller lifting cylinder; 2802, second sweep roller lifting cylinder; 300, hydraulic oil tank; 400, cooler; 500, return oil filter; 600, air filter; 700, liquid temperature gauge. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1The present invention provides a technical solution for a hydraulic system of a sweeper with a sweeping roller that can adapt to the road surface in terms of height, including a sweeping roller hydraulic system part 100 and a sweeping roller lifting hydraulic system part 200. The sweeping roller hydraulic system part 100 is used to drive the sweeping roller to rotate for cleaning. The sweeping roller lifting hydraulic system part 200 is used to complete the lifting and lowering action of the sweeping roller. The sweeping roller hydraulic system part includes an oil suction filter 110, a sweeping roller gear pump 120 that provides power for the sweeping roller hydraulic system, a sweeping roller pressure gauge 130, a proportional multi-way valve 140, a pressure sensor 150, and a sweeping roller motor 160; the sweeping roller gear pump 120 is a fixed displacement gear pump, and the low-pressure oil suction port of the sweeping roller gear pump 120 is connected in series with the oil suction filter 110 and then connected to the hydraulic oil tank 300, and the high-pressure oil port of the sweeping roller gear pump 120 is connected to the oil inlet P of the proportional multi-way valve 140 to provide power for the sweeping roller hydraulic system part; the proportional multi-way valve 140 The working oil ports A and B are respectively connected to the inlet and outlet of the sweeping roller motor 160. The opening of the valve core of the proportional multi-way valve 140 can be controlled by adjusting the opening size of the sweeping roller rotating knob, thereby controlling the start and stop and speed adjustment of the sweeping roller. The maximum working pressure of the sweeping roller hydraulic system can be adjusted by adjusting the pressure adjustment knob of the proportional multi-way valve 140, which can protect the sweeping roller hydraulic system from damage by high pressure and extend the service life of the hydraulic components. The set pressure value is 160bar. The sweeping roller pressure gauge 130 is installed at the high-pressure outlet of the sweeping roller gear pump 120 and is connected in parallel with the proportional multi-way valve 140 to detect the working pressure of the sweeping roller hydraulic system.

[0027] A pressure sensor 150 is connected in parallel between port A of the proportional multi-way valve 140 and the oil inlet of the sweeping roller motor 160. The pressure sensor 150 can detect the working pressure of the sweeping roller motor 160 and feed it back to the control system. The controller will always determine whether the feedback pressure is within the normal working pressure range. If it exceeds the normal working pressure range, the controller will issue relevant instructions to the sweeping roller lifting actuator to adjust the sweeping roller to maintain it in a normal working state. When the sweeping roller is cleaning on a relatively flat road surface, the normal working pressure of the sweeping roller motor 160 is basically stable at about 100 bar; when the sweeping roller is working on a working road surface with large fluctuations or the sweeping roller brush is worn to a certain extent, if the pressure sensor 150 detects that the working pressure of the sweeping roller motor 160 becomes low and is lower than the set minimum adjustment working pressure, the controller will issue a descending command to the sweeping roller lifting actuator to lower the sweeping roller, so that the contact area between the sweeping roller and the ground becomes larger. After the sweeping roller motor 160 reaches the set normal working pressure, the controller stops outputting the descending command, and the minimum adjustment working pressure setting value is 60 bar; on the contrary, if the pressure sensor 150 detects that the working pressure of the sweeping roller motor 160 becomes high and is higher than the set maximum adjustment working pressure, the controller will issue an ascending command to the sweeping roller lifting actuator to lower the sweeping roller, so that the contact area between the sweeping roller and the ground becomes smaller. After the working pressure of the sweeping roller motor 160 reaches the set normal working pressure, the controller stops outputting the ascending command, and the maximum adjustment working pressure setting value is 130 bar. The height of the sweeping roller can be adjusted through self-feedback to adapt to the cleaning of different road conditions. At the same time, the working state of the sweeping roller and sweeping brush after wear can be automatically adjusted, eliminating the need for manual adjustment of the height of the sweeping roller and sweeping brush, ensuring the road cleaning effect and improving the cleaning efficiency.

[0028] The sweep roller lifting hydraulic system 200 includes a sweep roller lifting gear pump 210, a sweep roller lifting pressure gauge 230, a sweep roller lifting hydraulic valve group part and a sweep roller lifting actuator, which provide power for the sweep roller lifting hydraulic system 200. The sweep roller lifting gear pump 210 is a quantitative gear pump, which is a series pump with the sweep roller gear pump 120 and shares a low-pressure oil suction port. The high-pressure oil outlet of the sweep roller lifting gear pump 210 is connected to the oil inlet P of the sweep roller lifting hydraulic valve group part, and at the same time, its high-pressure oil outlet is also connected in parallel with a sweep roller lifting pressure gauge 230, which can detect the working pressure of the sweep roller hydraulic lifting and lowering pressure system part.

[0029] The sweeping roller lifting hydraulic valve group part includes a sweeping roller lifting hydraulic valve block 240 that provides a working oil circuit for the sweeping roller lifting hydraulic system part 200, and two identical sweeping roller lifting electromagnetic reversing valves 250. The sweeping roller lifting actuator includes a first sweeping roller lifting cylinder 2801 and a second sweeping roller lifting cylinder 2802. The A and B ports of the two identical sweeping roller lifting electromagnetic reversing valves 250 are respectively connected to the rod chamber and rodless chamber oil ports of the first sweeping roller lifting cylinder 2801 and the second sweeping roller lifting cylinder 2802 through the four oil ports A1, B1, A2, and B2 of the sweeping roller lifting hydraulic valve block 240. By manually operating the knob, the left and right coils of the sweeping roller lifting electromagnetic reversing valve 250 can be energized. When the left coil of the sweeping roller lifting electromagnetic reversing valve 250 is energized, the hydraulic oil can be controlled to flow to the rodless chambers of the first sweeping roller lifting cylinder 2801 and the second sweeping roller lifting cylinder 2802, thereby driving the sweeping roller to descend for cleaning; when cleaning is not required, the right coil of the sweeping roller lifting electromagnetic reversing valve 250 is energized, which can control the hydraulic oil to flow to the rod chambers of the first sweeping roller lifting cylinder 2801 and the second sweeping roller lifting cylinder 2802, thereby driving the sweeping roller to rise to complete the cleaning work.

[0030] In order to prevent interference between manual control of the sweep roller actuator and the controller controlling the automatic lifting of the sweep roller actuator, the trigger condition for the controller to control the automatic lifting of the sweep roller actuator is set to whether the sweep roller motor 160 rotates. When the sweep roller motor 160 does not rotate, the controller does not participate in the lifting and lowering adjustment of the sweep roller actuator. If cleaning is required at this time, the one-key cleaning function can be started by controlling the one-key cleaning button to make the sweep roller actuator drive the sweep roller to drop to the position, and then the sweep roller motor 160 rotates to drive the sweep roller to rotate to perform cleaning; when the cleaning work is finished, the one-key cleaning button can be reset to end the one-key cleaning function. At this time, the sweep roller motor 160 stops rotating first, and then the sweep roller actuator drives the sweep roller to rise to end the cleaning work. The lifting and lowering of the sweep roller can also be controlled manually alone. At this time, the one-key cleaning function needs to be in the off state, that is, the sweep roller motor 160 does not rotate. If the controller detects that the sweep roller is in the working state, that is, when the sweep roller motor 160 rotates, the controller will intervene in the automatic control of the lifting and lowering adjustment of the sweep roller actuator.

[0031] Two identical sweeping roller lifting electromagnetic reversing valves 250 and sweeping roller lifting hydraulic valve blocks 240 are respectively stacked with two identical sweeping roller lifting superimposed one-way hydraulic locks 260 and two identical sweeping roller lifting superimposed double one-way throttle valves 270. The sweeping roller lifting superimposed one-way hydraulic locks 260 can ensure that the sweeping rollers remain in a lifted state and do not fall when the sweeper is not working, thereby improving safety performance; the lifting speed of the sweeping roller actuator can be adjusted by adjusting the sweeping roller lifting superimposed double one-way throttle valves 270.

[0032] The sweeping roller lifting hydraulic system 200 also includes an unloading relief valve 220. The oil inlet of the unloading relief valve 220 is connected in parallel with the oil inlet P of the sweeping roller lifting hydraulic valve group, and both are connected to the high-pressure oil outlet of the sweeping roller lifting gear pump 210. The oil return port of the unloading relief valve 220 is combined with the oil return port T of the sweeping roller lifting hydraulic valve block 240 through a three-way joint. The unloading relief valve 220 can limit the maximum pressure of the sweeping roller lifting hydraulic system 200, protect the safety of the hydraulic system, and extend the service life of the hydraulic components. Its set pressure value is 160 bar.

[0033] The oil return port T of the proportional multi-way valve 140 in the sweeping roller hydraulic system part and the oil return port T of the sweeping roller lifting hydraulic valve block 240 in the sweeping roller lifting hydraulic system part 200 are connected to the oil inlet of the cooler 400 after being merged through a three-way joint. The oil outlet of the cooler 400 is connected to the oil inlet behind the return oil filter 500. The return oil filter 500 is installed on the top of the hydraulic oil tank 300, and its oil outlet is connected to the oil tank.

[0034] The hydraulic cooler 400 can reduce the temperature of the hydraulic oil, protect the components in the hydraulic system, and prevent attenuation or failure due to high temperature, thereby extending their service life, reducing the system failure rate and improving the reliability of the system.

[0035] The return oil filter 500 can filter particles in the hydraulic oil to a certain extent. Maintaining the cleanliness of the system helps to reduce system failures and improve the reliability and overall performance of the system.

[0036] The liquid temperature gauge 700 is installed on the side of the hydraulic oil tank 300 to monitor the oil height and temperature in the hydraulic system and ensure that the volume system of the hydraulic oil in the hydraulic oil tank 300 operates within the appropriate temperature range, thereby extending the service life of the equipment and improving the performance of the system.

[0037] The air filter 600 is installed on the top of the oil tank to prevent particulate pollutants from entering the system through the oil tank breathing port and prevent particulate pollutants from mixing in during refueling, thereby extending the working cycle and service life of the oil and components and ensuring the normal operation of the hydraulic system. In addition, it can maintain the pressure in the oil tank in balance with the atmospheric pressure to avoid cavitation in the pump.

[0038] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A hydraulic system for a road sweeper with a sweeping roller height that is adaptive to the road surface, characterized in that: The invention comprises a sweeping roller hydraulic system part (100) and a sweeping roller lifting hydraulic system part (200), wherein the low-pressure oil suction port of the sweeping roller hydraulic system part (100) is communicated with a hydraulic oil tank (300), the sweeping roller hydraulic system part (100) and the sweeping roller lifting hydraulic system part (200) share a low-pressure oil suction port, the oil return port T of the sweeping roller hydraulic system part (100) and the oil return port T of the sweeping roller lifting hydraulic system part (200) are combined through a three-way joint and are communicated with an oil inlet of a cooler (400), the oil outlet of the cooler (400) is communicated with an oil inlet of a return oil filter (500), the return oil filter (500) is installed on the top of the hydraulic oil tank (300), and the oil outlet of the return oil filter (500) is communicated with the hydraulic oil tank (300).

2. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 1, characterized in that: The sweeping roller hydraulic system part (100) comprises an oil suction filter (110), a sweeping roller gear pump (120), a sweeping roller pressure gauge (130), a proportional multi-way valve (140), a pressure sensor (150) and a sweeping roller motor (160); the low-pressure oil suction port of the sweeping roller gear pump (120) is connected in series with the oil suction filter (110) and then communicated with the hydraulic oil tank (300); the high-pressure oil port of the sweeping roller gear pump (120) is communicated with the oil inlet P of the proportional multi-way valve (140); and the working oil ports A and B of the proportional multi-way valve (140) are respectively connected to the inlet and outlet of the sweeping roller motor (160).

3. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 2, characterized in that: A pressure sensor (150) is connected in parallel between port A of the proportional multi-way valve (140) and the oil inlet of the sweeping roller motor (160).

4. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 3, characterized in that: A sweep roller pressure gauge (130) is installed at the high-pressure outlet of the sweep roller gear pump (120), and the sweep roller pressure gauge (130) is connected in parallel with the proportional multi-way valve (140).

5. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 4, characterized in that: The sweeping roller lifting hydraulic system part (200) comprises a sweeping roller lifting gear pump (210), a sweeping roller lifting pressure gauge (230), a sweeping roller lifting hydraulic valve group part and a sweeping roller lifting actuator, wherein the sweeping roller lifting gear pump (210) and the sweeping roller gear pump (120) form a series pump and share a low-pressure oil suction port, and the high-pressure oil outlet of the sweeping roller lifting gear pump (210) is connected to an oil inlet P of the sweeping roller lifting hydraulic valve group part.

6. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 5, characterized in that: The sweeping roller lifting hydraulic valve group part comprises a sweeping roller lifting hydraulic valve block (240), two sweeping roller lifting electromagnetic reversing valves (250), and the sweeping roller lifting actuator comprises a first sweeping roller lifting oil cylinder (2801) and a second sweeping roller lifting oil cylinder (2802). The A and B ports of the two sweeping roller lifting electromagnetic reversing valves (250) are respectively connected to the rod chamber and rodless chamber oil ports on the first sweeping roller lifting oil cylinder (2801) and the second sweeping roller lifting oil cylinder (2802) through the four oil ports A1, B1, A2, and B2 of the sweeping roller lifting hydraulic valve block (240).

7. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 6, characterized in that: Two sweeping roller lifting superimposed one-way hydraulic locks (260) and two sweeping roller lifting superimposed double one-way throttle valves (270) are respectively superimposed between the two sweeping roller lifting electromagnetic reversing valves (250) and the sweeping roller lifting hydraulic valve block (240).

8. The hydraulic system of the sweeper roller height self-adapting road surface according to claim 7, characterized in that: The sweeping roller lifting hydraulic system part (200) further comprises a load relief valve (220), the oil inlet of the load relief valve (220) being connected in parallel with the oil inlet P of the sweeping roller lifting hydraulic valve group part and being connected with the high-pressure oil outlet of the sweeping roller lifting gear pump (210), and the oil return port of the load relief valve (220) being combined with the oil return port T of the sweeping roller lifting hydraulic valve block (240) via a three-way joint.

9. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 8, characterized in that: A sweep roller lifting pressure gauge (230) is connected in parallel between the high-pressure oil outlet of the sweep roller lifting gear pump (210) and the oil inlet P of the sweep roller lifting hydraulic valve group.

10. A hydraulic system for a road sweeper with a sweeping roller height adaptive to the road surface according to claim 9, characterized in that: An air filter (600) and a liquid temperature gauge (700) are installed on the hydraulic oil tank (300).

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