A grader leveling hydraulic system

Abstract

The utility model provides a kind of motor grader leveling hydraulic system, it is related to motor grader leveling field, the scheme used is: including oil tank, hydraulic pump, electric control leveling valve group, steering gear and multi-way reversing valve, hydraulic pump is load-sensitive variable pump, the oil inlet of hydraulic pump is communicated with oil tank, the oil outlet of hydraulic pump is respectively communicated with electric control leveling valve group, steering gear and multi-way reversing valve, electric control leveling valve group is communicated with spade knife lifting oil cylinder, multi-way reversing valve is communicated with multiple execution elements, still include shuttle valve one and shuttle valve two, two oil inlets of shuttle valve one are respectively communicated with the load-sensitive port of steering gear and the load-sensitive port of multi-way reversing valve, the oil outlet of shuttle valve one is communicated with the oil inlet of shuttle valve two, another oil inlet of shuttle valve two is communicated with the load-sensitive port of electric control leveling valve group, the oil outlet of shuttle valve two is communicated with the control oil port of hydraulic pump.The utility model can adjust the flow of pressure oil according to load demand, reach the energy-saving effect of oil supply on demand.

Description

Technical Field

[0001] This utility model relates to the field of grader leveling, and in particular to a grader leveling hydraulic system. Background Technology

[0002] The leveling hydraulic system of a grader is the core module for achieving its high-precision leveling operation. It is mainly used to control the lifting, tilting, and lateral movement of the scraper (shovel) to ensure the ground is flat. This system uses hydraulic power to drive the actuators, combined with sensors and a control system to achieve automated leveling, and is widely used in road construction, mining, farmland reclamation, and other scenarios.

[0003] When the hydraulic system of the grader is working, the gear pump draws oil from the tank through the suction filter. The discharged hydraulic oil is divided into two paths by the priority valve. One path prioritizes supplying oil to the steering gear, and the excess oil goes to the priority valve. The oil output from the priority valve is also divided into two paths. One path prioritizes supplying oil to the electronically controlled leveling valve assembly, and the excess oil goes to the multi-way directional valve. When the electronically controlled leveling valve assembly receives a control signal, it outputs a corresponding control flow according to the magnitude of the control signal, thereby automatically controlling the lifting cylinder. The excess hydraulic oil output by the pump flows back to the tank through the multi-way directional valve, oil cooler, and return oil filter. When the electronically controlled leveling valve assembly does not receive a control signal, it has no flow output, and all the hydraulic oil output by the pump enters the multi-way directional valve. At this time, the multi-way directional valve can be manually controlled, thereby manually controlling the blade movement.

[0004] When using the above technical solutions, because the hydraulic oil flow rate output by the gear pump is constant when the engine speed is constant and will not change due to load variations, the excess hydraulic oil will be converted into heat and lost during the return process after removing the hydraulic oil required by the load, resulting in power waste. Utility Model Content

[0005] To address the power waste problem in the existing hydraulic systems for graders, this invention provides a hydraulic system for graders that can adjust the flow rate of pressurized oil according to load requirements, achieving energy-saving effects through on-demand oil supply.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a hydraulic system for leveling a grader, including an oil tank, a hydraulic pump, an electrically controlled leveling valve group, a steering gear, and a multi-way directional valve. The hydraulic pump is a load-sensitive variable pump. The oil inlet of the hydraulic pump is connected to the oil tank. The oil outlet of the hydraulic pump is connected to the electrically controlled leveling valve group, the steering gear, and the multi-way directional valve respectively. The electrically controlled leveling valve group is connected to the blade lifting cylinder. The electrically controlled leveling valve group can be electrically connected to the grader's controller. The multi-way directional valve is connected to multiple actuators. It also includes a shuttle valve one and a shuttle valve two. The two oil inlets of the shuttle valve one are connected to the load-sensitive ports of the steering gear and the multi-way directional valve respectively. The oil outlet of the shuttle valve one is connected to one oil inlet of the shuttle valve two. The other oil inlet of the shuttle valve two is connected to the load-sensitive port of the electrically controlled leveling valve group. The oil outlet of the shuttle valve two is connected to the control port of the hydraulic pump.

[0007] This invention, through the synergistic action of a load-sensitive variable pump, shuttle valve one, and shuttle valve two, can transmit the maximum load signal to the hydraulic pump during operation, enabling the hydraulic pump to automatically adjust the output hydraulic oil flow according to the load flow demand. This ensures the normal operation of the lifting cylinder and other actuators, avoids excessive hydraulic oil output, achieves on-demand oil supply, and realizes energy-saving effects.

[0008] Furthermore, it also includes a priority valve, the oil outlet of the hydraulic pump is connected to the oil inlet of the priority valve, the oil outlet of the priority valve is connected to the electronically controlled leveling valve group, the steering gear and the multi-way directional valve respectively, and the load-sensitive port of the steering gear is connected to the load-sensitive port of the priority valve and then connected to one of the oil inlets of the shuttle valve.

[0009] This invention, by setting a priority valve, ensures that when multiple actuators are working simultaneously, the flow priority is sorted to ensure that critical actions are not interfered with by secondary actions.

[0010] Furthermore, the electronically controlled leveling valve assembly includes pilot valve one and pilot valve two. Pilot valve one and pilot valve two are electrically connected to the controller of the grader. The oil inlets of pilot valve one and pilot valve two are both connected to the oil outlet of the priority valve. The oil outlet of pilot valve one is connected to the control oil outlet of proportional directional valve one. The oil outlet of proportional directional valve one is connected to the oil inlet of one of the blade lifting cylinders. The oil inlet of proportional directional valve one is connected to the priority valve. The oil outlet of pilot valve two is connected to the control oil outlet of proportional directional valve two. The oil outlet of proportional directional valve two is connected to the oil inlet of another blade lifting cylinder. The oil inlet of proportional directional valve two is connected to the priority valve.

[0011] This invention, through the synergistic action of pilot valve one, pilot valve two, proportional directional valve one, and proportional directional valve two, combines the precision of electrical signals with the power of the hydraulic system to achieve precise control, rapid response, and intelligent coordination, significantly improving the working quality, efficiency, and economy of the grader.

[0012] Furthermore, the electronically controlled leveling valve assembly also includes a pilot pressure reducing valve. The oil inlet of the pilot pressure reducing valve is connected to the oil outlet of the priority valve. The oil outlet of the pilot pressure reducing valve is connected to the oil inlets of the first pilot valve and the second pilot valve, respectively. The oil drain port of the pilot pressure reducing valve is connected to the oil tank.

[0013] This invention, by setting a pilot pressure reducing valve, can ensure that the pilot hydraulic oil pressure is reduced, thus avoiding damage to pilot valve one and pilot valve two.

[0014] Furthermore, the electronically controlled leveling valve assembly also includes a relief valve, the oil inlet of which is connected to the oil outlet of the pilot pressure reducing valve, and the oil outlet of which is connected to the oil tank.

[0015] Furthermore, the electronically controlled leveling valve assembly also includes shuttle valve three and shuttle valve four. The oil outlet of shuttle valve three is connected to the oil inlet of shuttle valve two. The two oil inlets of shuttle valve three are respectively connected to the oil outlet of shuttle valve four and the load-sensitive port of proportional directional valve one. The oil outlet of shuttle valve three is connected to the oil inlet of shuttle valve two. The two oil inlets of shuttle valve four are respectively connected to the load-sensitive port of proportional directional valve two and the oil tank.

[0016] This invention, by setting shuttle valve three and shuttle valve four, can ensure that the larger load signal of the two proportional directional valves of the output electronically controlled leveling valve meets the working needs of the shovel lifting cylinder with a large load.

[0017] Furthermore, the oil inlet of the first proportional directional valve is connected to the priority valve through the first pressure compensation valve, and the oil inlet of the second proportional directional valve is connected to the priority valve through the second pressure compensation valve.

[0018] This invention, by setting a pressure compensation valve, can stabilize the flow distribution and adapt to load changes, ensuring that the movement speed of the shovel lifting cylinder is not affected by load pressure fluctuations.

[0019] Furthermore, there are two multi-way directional valves. The oil inlets of the two multi-way directional valves are respectively connected to the oil outlet of the priority valve, and the oil outlets of the two multi-way directional valves are respectively connected to the corresponding blade lifting cylinders. The load-sensitive ports of the two multi-way directional valves are connected to one of the oil inlets of the shuttle valve.

[0020] This invention utilizes a multi-way directional valve in conjunction with an electrically controlled leveling valve to drive the shovel lifting cylinder. The electrically controlled leveling valve assembly achieves high-precision adjustment, while the multi-way directional valve provides rapid coarse adjustment. The two complement each other, simultaneously improving operational accuracy and effectiveness. Furthermore, the multi-way directional valve can be degraded to manual operation in case of a malfunction in the electrically controlled leveling valve, ensuring continuous construction.

[0021] As can be seen from the above technical solutions, this utility model has the following advantages:

[0022] This utility model provides a hydraulic system for leveling a grader. Through the coordinated action of a load-sensitive variable pump, shuttle valve one, and shuttle valve two, the maximum load signal is transmitted to the hydraulic pump during operation. This allows the hydraulic pump to automatically adjust the output hydraulic oil flow according to the load flow demand, ensuring the lifting cylinder is properly positioned and avoiding excessive hydraulic oil output, achieving on-demand oil supply and energy savings. By setting a pilot valve and a proportional directional valve, the precision of the electrical signal is combined with the power of the hydraulic system, achieving precise control, rapid response, and intelligent coordination, significantly improving the grader's operating quality, efficiency, and economy. The inclusion of a priority valve ensures that when multiple actuators operate simultaneously, flow priority is used to ensure that critical actions are not interfered with by secondary actions. The pilot pressure reducing valve ensures reduced pilot hydraulic oil pressure, preventing damage to pilot valves one and two. Shuttle valves three and four ensure the output of the larger load signal from the two proportional directional valves of the electrically controlled leveling valve, meeting the operational needs of the large-load blade lifting cylinder. The pressure compensation valve stabilizes flow distribution and adapts to load changes, ensuring the blade lifting cylinder's movement speed is unaffected by load pressure fluctuations. The multi-way directional valve works in conjunction with the electrically controlled leveling valve to drive the blade lifting cylinder; the electrically controlled leveling valve assembly achieves high-precision adjustment, while the multi-way directional valve provides rapid coarse adjustment. These two systems complement each other, improving operational accuracy and effectiveness. Furthermore, in the event of a failure in the electrically controlled leveling valve assembly, manual operation of the multi-way directional valve ensures continuous construction. Attached Figure Description

[0023] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram illustrating the principle of a specific embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the leveling valve assembly in a specific embodiment of this utility model.

[0026] In the diagram: 1. Electrically controlled leveling valve assembly; 2. Shuttle valve II; 3. Hydraulic pump; 4. Oil tank; 5. Multi-way directional valve; 6. Shovel lifting cylinder; 7. Steering gear; 8. Priority valve; 9. Shuttle valve I; 10. Pilot valve II; 11. Proportional directional valve II; 12. Shuttle valve IV; 13. Pressure compensation valve II; 14. Proportional directional valve I; 15. Pressure compensation valve I; 16. Pilot relief valve; 18. Pilot pressure reducing valve; 19. Relief valve I; 20. Shuttle valve III; 21. Pilot valve I. Detailed Implementation

[0027] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0028] like Figure 1 As shown in the figure, this specific embodiment provides a leveling hydraulic system for a grader, including an oil tank 4, a hydraulic pump 3, an electrically controlled leveling valve assembly 1, a steering gear 7, a shuttle valve 9, a shuttle valve 2, and a multi-way directional valve 5. The hydraulic pump 3 is a load-sensitive variable pump. The oil inlet of the hydraulic pump 3 is connected to the oil tank 4, and the oil outlet of the hydraulic pump 3 is connected to the electrically controlled leveling valve assembly 1, the steering gear 7, and the multi-way directional valve 5, respectively. The electrically controlled leveling valve assembly 1 is connected to two blade lifting cylinders 6, which are responsible for adjusting the left and right blades, respectively. The electrically controlled leveling valve assembly 1 can be electrically connected to the grader's controller to receive electrical signals for adjusting the left and right blades, thus enabling automatic adjustment. The multi-way directional valve 5 is connected to multiple actuators. The shuttle valve 9... The two oil inlets are respectively connected to the load-sensitive port of the steering gear 7 and the load-sensitive port of the multi-way directional valve 5. The oil outlet of shuttle valve 1 9 is connected to one oil inlet of shuttle valve 2, and the other oil inlet of shuttle valve 2 is connected to the load-sensitive port of the electronically controlled leveling valve group 1. The oil outlet of shuttle valve 2 is connected to the control oil port of the hydraulic pump 3. In this specific embodiment, the multi-way directional valve 5 and the steering gear 7 are selected by shuttle valve 1 9, and the larger load signal is output. Then, after being selected by shuttle valve 2, the largest load signal among the electronically controlled leveling valve group 1, the multi-way directional valve 5 and the steering gear 7 is output. This allows the hydraulic pump 3, i.e., the load-sensitive variable pump, to adjust the output flow according to the largest load signal, avoiding excessive or insufficient flow and meeting the working requirements.

[0029] This specific embodiment, through the synergistic action of the load-sensitive variable pump, shuttle valve 9, and shuttle valve 2, can transmit the maximum load signal to the hydraulic pump 3 during operation, enabling the hydraulic pump 3 to automatically adjust the output hydraulic oil flow according to the load flow demand, ensuring the normal operation of the shovel lifting cylinder 6 and other actuators, avoiding excessive output of hydraulic oil, achieving on-demand oil supply, achieving energy-saving effect, and enabling automatic adjustment.

[0030] When a grader is working, the steering system is the core mechanism ensuring equipment safety and operational stability. When steering and blade lifting operate simultaneously, the flow required for steering must be met first, and the remaining flow is then supplied to actuators such as the blade lifting cylinder. This prevents steering from becoming sluggish or even malfunctioning due to excessive flow being consumed by other actions of the grader. Therefore, if... Figure 1 As shown, in this specific embodiment, a priority valve 8 is also included. The oil outlet of the hydraulic pump 3 is connected to the oil inlet of the priority valve 8. The oil outlet of the priority valve 8 is connected to the electronically controlled leveling valve group 1, the steering gear 7, and the multi-way directional valve 5, respectively. The load-sensitive port of the steering gear 7 is connected to the load-sensitive port of the priority valve 8 and then to one of the oil inlets of the shuttle valve 9. In this specific embodiment, the EF port of the priority valve 8 is connected to the multi-way directional valve 5 and the electronically controlled leveling valve group 1, and the CF port of the priority valve 8 is connected to the oil inlet of the hydraulic oil circuit of the steering gear 7.

[0031] To improve the accuracy of controlling the lifting cylinder 6 of the shovel blade, such as Figure 1 and Figure 2As shown in this specific embodiment, the electrically controlled leveling valve assembly 1 includes a pilot valve 21 and a pilot valve 10. The pilot valve 21 and the pilot valve 10 are electrically connected to the controller of the grader. The oil inlets of both pilot valve 21 and pilot valve 10 are connected to the oil outlet of the priority valve 8. The oil outlet of pilot valve 21 is connected to the control oil port of proportional directional valve 14. The oil outlet of proportional directional valve 14 is connected to the oil inlet of a blade lifting cylinder 6. The return oil port of the blade lifting cylinder 6 is connected to the return oil inlet of proportional directional valve 14. The return oil outlet of proportional directional valve 14... The proportional directional valve 14 is connected to the oil tank 4. Its inlet is connected to the priority valve 8. The outlet of the pilot valve 10 is connected to the control port of the proportional directional valve 11. The outlet of the proportional directional valve 11 is connected to the inlet of another blade lifting cylinder 6. The return port of the blade lifting cylinder 6 is connected to the return inlet of the proportional directional valve 11. The return outlet of the proportional directional valve 11 is connected to the oil tank 4. The inlet of the proportional directional valve 11 is connected to the priority valve 8. In this specific embodiment, each of the main valve cores of the proportional directional valve 14 and the proportional directional valve 11 has a control oil chamber (A and B). Pilot oil enters different oil chambers through the switching of the corresponding pilot valves, realizing bidirectional movement of the valve core (e.g., A). When oil enters chamber B, the valve core moves to the right; when oil enters chamber B, it moves to the left. With this configuration, pilot valves 21 and 10 convert the controller's electrical signal into a hydraulic oil pressure signal. The pilot oil flowing to pilot valves 21 and 10 enters the control ports of proportional directional valves 14 and 11 at corresponding pressure outputs. Within the control oil chambers of proportional directional valves 14 and 11, the valve core is pushed to move in the corresponding direction and displacement, thereby achieving flow control. This allows for precise adjustment of the displacement of the left and right blade lifting cylinders 6. Through the coordinated action of pilot valves 21, 10, 14, and 11, the accuracy of the controller's electrical signal is combined with the power of the hydraulic system, achieving precise control and rapid... The responsive and intelligent coordination significantly improves the working quality, efficiency, and economy of the grader. Furthermore, the electronically controlled leveling valve assembly 1 also includes a pilot pressure reducing valve 18. The oil inlet of the pilot pressure reducing valve 18 is connected to the oil outlet of the priority valve 8, and the oil outlet of the pilot pressure reducing valve 18 is connected to the oil inlets of the first pilot valve 21 and the second pilot valve 10, respectively. The oil drain port of the pilot pressure reducing valve 18 is connected to the oil tank 4. By setting the pilot pressure reducing valve 18, the pilot hydraulic oil pressure can be reduced, avoiding damage to the first pilot valve 21 and the second pilot valve 10. The electronically controlled leveling valve assembly 1 also includes an overflow valve 19. The oil inlet of the overflow valve 19 is connected to the oil outlet of the pilot pressure reducing valve 18, and the oil outlet of the overflow valve 19 is connected to the oil tank 4.By installing relief valve 19, excessive pressure in the pilot oil circuit can be avoided, preventing damage to hydraulic components.

[0032] Preferably, to ensure that the load-sensitive port of the electronically controlled leveling valve assembly 1 outputs the larger load signal from the two proportional directional valves, so that the left and right blade lifting cylinders 6 can operate normally, such as... Figure 2 As shown, in this specific embodiment, the electronically controlled leveling valve group 1 further includes shuttle valve three 20 and shuttle valve four 12. The oil outlet of shuttle valve three 20 is connected to the oil inlet of shuttle valve two 2. The two oil inlets of shuttle valve three 20 are respectively connected to the oil outlet of shuttle valve four 12 and the load sensitive port of proportional directional valve one 14. The oil outlet of shuttle valve three 20 is connected to the oil inlet of shuttle valve two 2. The two oil inlets of shuttle valve four 12 are respectively connected to the load sensitive port of proportional directional valve two 11 and the oil tank 4. With this configuration, the load signal of proportional directional valve two 11 is output through shuttle valve four 12. The load signals of proportional directional valve one 14 and proportional directional valve two 11 can be compared through shuttle valve three 20, and a larger load signal is output. This allows shuttle valve one 9 to compare the maximum load signal of electronically controlled leveling valve group 1 with the load of steering gear 7 and multi-way directional valve 5 to meet the maximum load requirement.

[0033] Furthermore, such as Figure 2 As shown, the oil inlet of the proportional directional valve 14 is connected to the priority valve 8 through the pressure compensation valve 15, and the oil inlet of the proportional directional valve 11 is connected to the priority valve 8 through the pressure compensation valve 13. By setting the pressure compensation valve, the pressure difference between the inlet and outlet of the corresponding proportional directional valve is kept constant, ensuring that the pressure through the corresponding proportional directional valve does not fluctuate with the change of hydraulic oil flow after adjustment.

[0034] To enhance the reliability of hydraulic systems, such as Figure 1 As shown, in this specific embodiment, two multi-way directional valves 5 are provided. The oil inlets of the two multi-way directional valves 5 are respectively connected to the oil outlet of the priority valve 8, and the oil outlets of the two multi-way directional valves 5 are respectively connected to the corresponding blade lifting cylinders 6. The load-sensitive ports of the two multi-way directional valves 5 are connected to one oil inlet of the shuttle valve 9. With this configuration, the two blade lifting cylinders 6 can be driven in concert through the multi-way directional valves 5 and the electrically controlled leveling valve group 1. The electrically controlled leveling valve group 1 achieves high-precision adjustment, while the multi-way directional valves 5 provide rapid coarse adjustment. The two complement each other, improving both the accuracy and effect of the operation. Furthermore, in the event of a failure of the electrically controlled leveling valve group 1, the multi-way directional valves 5 can be manually operated to ensure the continuity of construction.

[0035] In this specific embodiment, such as Figure 2As shown, the EF port of the priority valve 8 is also connected to the pilot relief valve 16. The oil inlet of the pilot relief valve 16 is connected to the EF port of the priority valve 8, and the oil outlet of the pilot relief valve 16 is connected to the oil tank 4.

[0036] In this specific embodiment, the multiple actuators connected by the two multi-way directional valves 5 include a ripper cylinder, a blade side-out cylinder, a blade angle adjustment cylinder, a rotary motor, a blade tilting cylinder, a frame steering cylinder, a front wheel tilting cylinder, a front bulldozer blade cylinder, and a front wheel steering cylinder.

[0037] The process of the grader automatically adjusting the blade position is as follows:

[0038] One or more GNSS antennas are installed on the blade or other parts of the grader. These antennas receive navigation signals from satellites to obtain the grader's position information, including longitude, latitude, and elevation. The grader is also equipped with various other sensors to help determine the blade's attitude. The grader establishes a coordinate system with a fixed point or plane as a reference. It uses a GNSS receiver to receive and process the signals from the GNSS antennas, calculates the position of the GNSS antenna phase center, and combines the angle and displacement information measured by the sensors. Through specific algorithms and formulas, it calculates the blade's position vector and attitude information in the coordinate system, including the blade's lifting height, tilt angle, and lateral displacement. The calculated actual position and attitude of the blade are compared with the pre-set target position and attitude to obtain the deviation. The target position and attitude information can come from a digital work site model or be a set value input by the operator on the control interface according to the work requirements. The controller calculates the direction and magnitude of adjustment required based on the deviation and generates corresponding control signals. The control signals are transmitted to the grader's leveling hydraulic system to drive the corresponding blade lifting cylinder to perform the action.

[0039] The working process of the leveling hydraulic system of this grader is as follows:

[0040] Hydraulic pump 3 draws oil from oil tank 4. The discharged hydraulic oil passes through priority valve 8 to steering gear 7, electronically controlled leveling valve group 1, and two parallel multi-way directional valves 5. After selection by shuttle valve 1 9 and shuttle valve 2 1, the maximum load signal among multi-way directional valves 5, steering gear 7, and electronically controlled leveling valve group 1 is transmitted to hydraulic pump 3. Hydraulic pump 3 automatically adjusts the output flow according to the load requirements to meet the working needs. When the blade height needs to be adjusted, hydraulic oil passes through priority valve 8 to the two multi-way directional valves 5, and drives the corresponding blade lifting cylinder 6 to actuate through multi-way directional valves 5, realizing coarse adjustment of the blade. At the same time, hydraulic oil passes through priority valve 8EF port to pressure compensation valve 1 15, pressure compensation valve 2 13, and pilot pressure reducing valve 18. When pilot valve 1 21 and pilot valve 2 10 receive the corresponding... Upon receiving the corresponding electrical signal, a pilot hydraulic oil of a certain pressure is output, driving the valve cores of proportional directional valve 14 and proportional directional valve 21 to move a corresponding distance in the corresponding direction. This causes pressure compensation valve 15 and pressure compensation valve 23 to connect to the A1 ports of proportional directional valve 14 and proportional directional valve 21, respectively, and the B1 ports of proportional directional valve 14 and proportional directional valve 21 to connect to the oil tank 4. The hydraulic oil then enters the two blade lifting cylinders 6, thereby driving the blade lifting cylinders 6 to achieve millimeter-level movements and realize fine-tuning of the blade. When it is not necessary to adjust the blade height, the multi-way directional valve 5 is disconnected from the corresponding blade lifting cylinder 6. At the same time, the valve cores of proportional directional valve 14 and proportional directional valve 21 are in the neutral position, and the hydraulic oil cannot reach the blade lifting cylinder 6.

[0041] As can be seen from the above specific embodiments, this utility model has the following beneficial effects:

[0042] 1. Through the coordinated action of the load-sensitive variable pump, shuttle valve 9 and shuttle valve 2, the maximum load signal can be transmitted to the hydraulic pump 3 during operation, so that the hydraulic pump 3 can automatically adjust the output hydraulic oil flow according to the load flow demand, ensuring the lifting cylinder and avoiding excessive output of hydraulic oil, achieving on-demand oil supply, achieving energy saving effect, and can also automatically adjust the blade position.

[0043] 2. By setting pilot valves and proportional directional valves, the accuracy of electrical signals can be combined with the power of the hydraulic system to achieve precise control, rapid response, and intelligent coordination, significantly improving the working quality, efficiency, and economy of the grader;

[0044] 3. By setting priority valve 8, it can be ensured that when multiple actuators are working at the same time, the flow priority is sorted to ensure that the critical action is not disturbed by the secondary action;

[0045] 4. By setting the pilot pressure reducing valve 18, the pilot hydraulic oil pressure can be reduced, thus avoiding damage to the pilot valve 1 21 and the pilot valve 2 10.

[0046] 5. By setting shuttle valve 3 20 and shuttle valve 4 12, the larger load signal of the two proportional directional valves of the output electronic leveling valve can be guaranteed to meet the working needs of the shovel lifting cylinder 6 with a larger load.

[0047] 6. By setting a pressure compensation valve, the flow distribution can be stabilized and the load changes can be adapted to ensure that the movement speed of the blade lifting cylinder 6 is not affected by load pressure fluctuations;

[0048] 7. By setting up a multi-way directional valve 5 in conjunction with the electronically controlled leveling valve to drive the shovel lifting cylinder 6, the electronically controlled leveling valve group 1 achieves high-precision adjustment, while the multi-way directional valve 5 provides rapid coarse adjustment. The two complement each other, improving both the accuracy and effectiveness of the operation. Furthermore, in the event of a failure of the electronically controlled leveling valve group 1, the multi-way directional valve 5 can be manually operated to ensure the continuity of construction.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A grade laver leveling hydraulic system comprising an oil tank (4), a hydraulic pump (3), an electrically controlled leveling valve group (1), a steering gear (7) and a multi-way directional valve (5), characterized in that: The hydraulic pump (3) is a load-sensitive variable pump. The inlet of the hydraulic pump (3) is connected to the oil tank (4). The outlet of the hydraulic pump (3) is connected to the electrically controlled leveling valve group (1), the steering gear (7), and the multi-way directional valve (5). The electrically controlled leveling valve group (1) is connected to two blade lifting cylinders (6). The electrically controlled leveling valve group (1) can be electrically connected to the controller of the grader. The multi-way directional valve (5) is connected to multiple actuators. Includes shuttle valve one (9) and shuttle valve two (2). The two oil inlets of shuttle valve one (9) are connected to the load sensitive port of the steering gear (7) and the load sensitive port of the multi-way directional valve (5), respectively. The oil outlet of shuttle valve one (9) is connected to one oil inlet of shuttle valve two (2). The other oil inlet of shuttle valve two (2) is connected to the load sensitive port of the electronically controlled leveling valve group (1). The oil outlet of shuttle valve two (2) is connected to the control oil port of the hydraulic pump (3).

2. The leveling hydraulic system for a grader as described in claim 1, characterized in that, It also includes a priority valve (8), the oil outlet of the hydraulic pump (3) is connected to the oil inlet of the priority valve (8), the oil outlet of the priority valve (8) is connected to the electronically controlled leveling valve group (1), the steering gear (7) and the multi-way reversing valve (5) respectively, and the load sensitive port of the steering gear (7) is connected to the load sensitive port of the priority valve (8) and then connected to one of the oil inlets of the shuttle valve (9).

3. The leveling hydraulic system for a grader as described in claim 2, characterized in that, The electrically controlled leveling valve assembly (1) includes a pilot valve one (21) and a pilot valve two (10). The pilot valve one (21) and the pilot valve two (10) can be electrically connected to the controller of the grader. The oil inlets of the pilot valve one (21) and the pilot valve two (10) are connected to the oil outlet of the priority valve (8). The oil outlet of the pilot valve one (21) is connected to the control oil port of the proportional directional valve one (14). The oil outlet of the first proportional directional valve (14) is connected to the oil inlet of one of the blade lifting cylinders (6), the oil inlet of the first proportional directional valve (14) is connected to the priority valve (8), the oil outlet of the second pilot valve (10) is connected to the control oil port of the second proportional directional valve (11), the oil outlet of the second proportional directional valve (11) is connected to the oil inlet of another blade lifting cylinder (6), and the oil inlet of the second proportional directional valve (11) is connected to the priority valve (8).

4. The leveling hydraulic system for a grader as described in claim 3, characterized in that, The electrically controlled leveling valve assembly (1) also includes a pilot pressure reducing valve (18). The oil inlet of the pilot pressure reducing valve (18) is connected to the oil outlet of the priority valve (8). The oil outlet of the pilot pressure reducing valve (18) is connected to the oil inlets of the first pilot valve (21) and the second pilot valve (10) respectively. The oil drain port of the pilot pressure reducing valve (18) is connected to the oil tank (4).

5. The leveling hydraulic system for a grader as described in claim 4, characterized in that, The electrically controlled leveling valve assembly (1) also includes an overflow valve (19), the oil inlet of which is connected to the oil outlet of the pilot pressure reducing valve (18), and the oil outlet of the overflow valve (19) is connected to the oil tank (4).

6. The leveling hydraulic system for a grader as described in claim 5, characterized in that, The electronically controlled leveling valve assembly (1) also includes shuttle valve three (20) and shuttle valve four (12). The oil outlet of shuttle valve three (20) is connected to the oil inlet of shuttle valve two (2). The two oil inlets of shuttle valve three (20) are respectively connected to the oil outlet of shuttle valve four (12) and the load sensitive port of proportional directional valve one (14). The oil outlet of shuttle valve three (20) is connected to the oil inlet of shuttle valve two (2). The two oil inlets of shuttle valve four (12) are respectively connected to the load sensitive port of proportional directional valve two (11) and the oil tank (4).

7. The grader leveling hydraulic system as described in claim 6, characterized in that, The oil inlet of the first proportional directional valve (14) is connected to the priority valve (8) through the first pressure compensation valve (15), and the oil inlet of the second proportional directional valve (11) is connected to the priority valve (8) through the second pressure compensation valve (13).

8. The leveling hydraulic system for a grader as described in claim 4, characterized in that, There are two multi-way directional valves (5). The oil inlets of the two multi-way directional valves (5) are respectively connected to the oil outlet of the priority valve (8). The oil outlets of the two multi-way directional valves (5) are respectively connected to the corresponding blade lifting cylinder (6). The load sensitive ports of the two multi-way directional valves (5) are connected to one of the oil inlets of the shuttle valve (9).

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