Lifting speed regulating system of mining dump truck and mining dump truck

Abstract

According to the lifting speed regulating system of the mining dump truck, two oil outlets of a lifting pump are connected with oil inlets of a first main valve element and a second main valve element respectively, an oil outlet of the first main valve element is connected to a rodless cavity of the lifting system, and an oil outlet of the second main valve element is connected to a rod cavity of the lifting system. The control end of the first main valve element and the control end of the second main valve element are connected to two working oil ports of the lifting proportional valve respectively. A pilot oil way communicated with the lifting proportional valve is divided into a first pilot sub-oil way connected to the first sub-oil way and a second pilot sub-oil way connected to the second sub-oil way, a bypass oil way connected with the oil return tank assembly is arranged on the first pilot sub-oil way, and a bypass valve is arranged on the bypass oil way. An oil inlet of the first main oil way control valve is connected with the first sub oil way, an oil outlet of the first main oil way control valve is connected with the oil return tank assembly, one control end of the first main oil way control valve is connected with the first sub oil way, and the other control end of the first main oil way control valve is connected to the first pilot sub oil way after passing through the first one-way throttle valve. The utility model further relates to a mining dump truck.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, and in particular to a lifting speed regulation system for a mining dump truck and the mining dump truck itself. Background Technology

[0002] Mining dump trucks are heavy-duty vehicles specifically designed for transporting materials in harsh environments such as mines and quarries. Their primary function is to transport materials such as ore and sand from mining sites to designated storage or processing locations. A hydraulic lifting system is an indispensable part of modern mining dump trucks. Through hydraulic assistance, the vehicle can quickly and safely unload cargo, significantly improving work efficiency. However, existing technology has some significant drawbacks in practical applications. First, during the descent of the cargo box, the system still uses a dual-pump oil supply. If the driver mistakenly increases the throttle, the engine speed will be too high, causing the cargo box to descend too quickly and resulting in a violent impact on the vehicle body. This can not only damage the hydraulic cylinder seals or deform the hydraulic cylinder itself, but also pose a threat to the safety of the operator and surrounding personnel. Furthermore, the rapidly descending cargo box generates significant noise and impact, further increasing operational risks. Second, when the cargo box descends too quickly, the hydraulic oil generates a large amount of heat due to friction and compression expansion as it flows through valves and pipelines. Overheating of the hydraulic system not only leads to hydraulic oil deterioration but also accelerates the wear and aging of hydraulic components, shortening their lifespan. At the same time, it will increase the risk of system leakage and reduce overall efficiency. Therefore, in order to prevent the cargo box from descending too quickly and reduce loss of life and property, the deceleration control of the cargo box and the cooling of the hydraulic system are particularly important. Utility Model Content

[0003] In view of this, the present invention provides a lifting speed regulation system for mining dump trucks, which can reduce the lifting and lowering speed of mining dump trucks, reduce the impact caused by the lowering of the hydraulic cylinder, and improve the service life of the hydraulic cylinder and equipment.

[0004] This utility model provides a lifting speed control system for a mining dump truck, comprising a lifting pump, a first main oil circuit control valve, a bypass valve, a first main valve core, a second main valve core, a lifting proportional valve, and an oil tank assembly, wherein:

[0005] The inlet of the lifting pump is connected to the oil tank assembly. The two outlets of the lifting pump are merged into a main oil circuit through a first sub-oil circuit and a second sub-oil circuit, and then connected to the inlet of the first main valve core and the inlet of the second main valve core, respectively. The return ports of the first main valve core and the second main valve core are connected back to the oil tank assembly. The outlet of the first main valve core is connected to the rodless chamber of the lifting system, and the outlet of the second main valve core is connected to the rod chamber of the lifting system.

[0006] One control terminal of the first main valve core is connected to one of the working ports of the lifting proportional valve, and the other control terminal of the first main valve core is connected to the oil line between the first main valve core and the lifting system; one control terminal of the second main valve core is connected to the other working port of the lifting proportional valve, and the other control terminal of the second main valve core is connected to the oil line between the second main valve core and the lifting system.

[0007] The pilot oil circuit connected to the oil inlet of the lifting proportional valve is divided into a first pilot sub-oil circuit and a second pilot sub-oil circuit at the end away from the lifting proportional valve. The first pilot sub-oil circuit is connected to the first sub-oil circuit, and the second pilot sub-oil circuit is connected to the second sub-oil circuit. A bypass oil circuit connecting back to the oil tank assembly is provided on the first pilot sub-oil circuit, and a bypass valve is provided on the bypass oil circuit.

[0008] The inlet of the first main oil circuit control valve is connected to the first sub-oil circuit, and the outlet of the first main oil circuit control valve is connected back to the oil tank assembly. One control terminal of the first main oil circuit control valve is connected to the first sub-oil circuit, and the other control terminal of the first main oil circuit control valve is connected to the first pilot sub-oil circuit after passing through the first one-way throttle valve.

[0009] Furthermore, the oil outlet of the first main oil circuit control valve is connected back to the return oil tank assembly through the first return oil circuit, and a cooler is provided on the first return oil circuit; the bypass oil circuit is connected to the first return oil circuit at the end away from the first pilot sub-oil circuit.

[0010] Furthermore, a first throttle valve is provided at the end of the first pilot sub-oil circuit near the first sub-oil circuit, and a second throttle valve is provided at the end of the second pilot sub-oil circuit near the second sub-oil circuit.

[0011] Furthermore, it also includes a second main oil circuit control valve, the oil inlet of which is connected to the second sub-oil circuit, the oil outlet of which is connected back to the oil tank assembly, one of the control terminals of the second main oil circuit control valve being connected to the second sub-oil circuit, and the other control terminal of the second main oil circuit control valve being connected to the second pilot sub-oil circuit of the second main oil circuit control valve via a second one-way throttle valve.

[0012] Furthermore, it also includes a first main relief valve connected in parallel with the first main oil circuit control valve, and a second main relief valve connected in parallel with the second main oil circuit control valve.

[0013] Furthermore, a first filter is provided on the first sub-oil line, and a second filter is provided on the second sub-oil line.

[0014] Furthermore, a first check valve is provided at the end of the main oil circuit near the first sub-oil circuit, and a second check valve is provided at the end of the main oil circuit near the second sub-oil circuit.

[0015] Furthermore, the oil return ports of the first main valve core and the second main valve core are both connected to the main oil return circuit. The main oil return circuit is connected to a second oil return circuit and a third oil return circuit that are connected to the oil tank assembly. The second oil return circuit is equipped with a first low-pressure relief valve, and the third oil return circuit is equipped with a second low-pressure relief valve.

[0016] Furthermore, the pilot oil circuit near the lifting proportional valve splits into a first branch and a second branch, respectively connecting to the two oil inlets of the lifting proportional valve. A third check valve is provided on the first branch. One working oil return of the lifting proportional valve is connected to the control end of the first main valve core through a first connecting oil circuit, and the other working oil return of the lifting proportional valve is connected to the control end of the second main valve core through a second connecting oil circuit. The return port of the lifting proportional valve is connected to the return oil tank assembly. The lifting proportional valve includes a lifting position, a lowering position, and a normal position. When the lifting proportional valve is in the lifting position, the first branch is connected to the first connecting oil circuit. When the lifting proportional valve is in the lowering position, the first branch is connected to the second connecting oil circuit. When the lifting proportional valve is in the normal position, the second branch is connected to the return port of the lifting proportional valve.

[0017] This utility model also provides a mining dump truck, including the above-mentioned lifting and speed regulation system for the mining dump truck.

[0018] In summary, the lifting speed control system of the mining dump truck and the mining dump truck of this utility model have the following beneficial effects:

[0019] 1. By adding a bypass valve, the oil from one of the pumps in the lifting pump (double gear pump) is unloaded through the first main oil circuit control valve, thereby reducing the lifting and lowering speed of the dump truck and preventing the cargo box from falling rapidly. This reduces the impact caused by the cylinder descent to a certain extent, thereby improving the safety and reliability of the system and extending the service life of the cylinder and equipment.

[0020] 2. In the lowering mode, the flow rate of oil entering the lifting cylinder is halved, and the remaining oil is completely cooled by the cooler in the first return oil circuit. This increases the system's cooling efficiency and further improves the service life of the cylinder and equipment.

[0021] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the lifting and speed regulation system of a mining dump truck according to a preferred embodiment of the present invention.

[0023] Figure 2 A schematic diagram of the lifting principle of the cargo box in the lifting and speed regulation system of the mining dump truck according to a preferred embodiment of this utility model.

[0024] Figure 3 A schematic diagram of the cargo box descent principle in the lifting and speed regulation system of a mining dump truck according to a preferred embodiment of this utility model. Detailed Implementation

[0025] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the present utility model will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0026] Figure 1 This is a schematic diagram of the lifting and speed control system of a mining dump truck according to a preferred embodiment of this utility model. Please refer to [link / reference]. Figure 1 The lifting speed control system of the mining dump truck in this embodiment includes a lifting pump 1, a first main oil circuit control valve 7, a second main oil circuit control valve 15, a bypass valve 9, a first main valve core 10, a second main valve core 22, a lifting proportional valve 12, a first low-pressure relief valve 17, a second low-pressure relief valve 21, a first throttle valve 23, a second throttle valve 20, an oil tank assembly 24, and a cooler 25.

[0027] The lifting pump 1 is a double gear pump. The oil inlet of the lifting pump 1 is connected to the oil tank assembly 24. The two oil outlets of the lifting pump 1 are merged into the main oil circuit 100 through the first sub-oil circuit 101 and the second sub-oil circuit 102, and then connected to the oil inlets of the first main valve core 10 and the second main valve core 22 respectively. The oil return ports of the first main valve core 10 and the second main valve core 22 are connected to the return oil tank assembly 24. The oil outlet of the first main valve core 10 is connected to the rodless chamber of the lifting cylinder in the lifting system 11, and the oil outlet of the second main valve core 22 is connected to the rod chamber of the lifting cylinder in the lifting system 11.

[0028] One control terminal of the first main valve core 10 is connected to one working port of the lifting proportional valve 12 via the first connecting oil passage 301. The other control terminal of the first main valve core 10 is connected to the oil passage between the first main valve core 10 and the lifting cylinder via a throttle valve. At the same time, the oil passage between the first main valve core 10 and the lifting system 11 and the first connecting oil passage 301 are also connected via a one-way throttle valve. One control terminal of the second main valve core 22 is connected to the other working port of the lifting proportional valve 12 via the second connecting oil passage 302. The other control terminal of the second main valve core 22 is connected to the oil passage between the second main valve core 22 and the lifting system 11 via a one-way throttle valve. At the same time, the oil passage between the second main valve core 22 and the lifting cylinder and the second connecting oil passage 302 are also connected via a one-way throttle valve.

[0029] The pilot oil passage 200, connected to the inlet of the lifting proportional valve 12, splits into a first pilot sub-passage 4 and a second pilot sub-passage 19 at the end furthest from the lifting proportional valve 12. The first pilot sub-passage 4 is connected to the first sub-passage 101, and the second pilot sub-passage 19 is connected to the second sub-passage 102. The first pilot sub-passage 4 is equipped with a bypass oil passage 103 connecting to the return oil tank assembly 24, and a bypass valve 9 is installed on the bypass oil passage 103. One end of the bypass valve 9 is connected to the first pilot sub-passage 4, and the other end is connected to the return oil tank assembly 24. The bypass valve 9 is a two-position, two-way solenoid directional valve, and its opening and closing are controlled by controlling the energization or de-energization of the electronic control terminal.

[0030] Furthermore, a first throttle valve 23 is provided at the end of the first pilot sub-oil circuit 4 near the first sub-oil circuit 101, and a second throttle valve 20 is provided at the end of the second pilot sub-oil circuit 19 near the second sub-oil circuit 102.

[0031] The inlet of the first main oil circuit control valve 7 is connected to the first sub-oil circuit 101, and the outlet of the first main oil circuit control valve 7 is connected to the return oil tank assembly 24 via the first return oil circuit 106. One control terminal of the first main oil circuit control valve 7 is connected to the first sub-oil circuit 101, and the other control terminal of the first main oil circuit control valve 7 is connected to the first pilot sub-oil circuit 4 via the first one-way throttle valve 5. A cooler 25 is provided on the first return oil circuit 106 to cool the oil returning from the first return oil circuit 106 to the oil tank assembly 24. In this embodiment, the bypass oil circuit 103, located away from the first pilot sub-oil circuit 4, is connected to the first return oil circuit 106, and the connection point is located between the first main oil circuit control valve 7 and the cooler 25. That is, the pilot oil flowing back from the bypass oil circuit 103 will also be cooled by the cooler 25.

[0032] Furthermore, the lifting speed control system also includes a first main relief valve 8 connected in parallel with the first main oil circuit control valve 7. That is, the oil inlet and control end of the first main relief valve 8 are both connected to the first sub-oil circuit 101, and the oil outlet of the first main relief valve 8 is connected to the first return oil circuit 106.

[0033] The inlet of the second main oil circuit control valve 15 is connected to the second sub-oil circuit 102, and the outlet of the second main oil circuit control valve 15 is connected to the return oil tank assembly 24. One of the control terminals of the second main oil circuit control valve 15 is connected to the second sub-oil circuit 102, and the other control terminal of the second main oil circuit control valve 15 is connected to the second pilot sub-oil circuit 19 after passing through the second one-way throttle valve 18.

[0034] Furthermore, the lifting speed control system also includes a second main relief valve 14 connected in parallel with the second main oil circuit control valve 15. That is, the oil inlet and control end of the second main relief valve 14 are both connected to the second sub-oil circuit 102, and the oil outlet of the second main relief valve 14 is connected to the return oil tank assembly 24.

[0035] Furthermore, a first filter 2 is provided on the first sub-oil circuit 101, and a second filter 3 is provided on the second sub-oil circuit 102. The first filter 2 and the second filter 3 are used to filter the oil returning to the oil tank assembly 24.

[0036] Furthermore, a first check valve 6 is provided at the end of the main oil circuit 100 near the first sub-oil circuit 101, and a second check valve 16 is provided at the end of the main oil circuit 100 near the second sub-oil circuit 102.

[0037] Furthermore, the return ports of the first main valve core 10 and the second main valve core 22 are both connected to the main return oil passage 105. The main return oil passage 105 is connected to a second return oil passage 107 and a third return oil passage 108, which are connected to the oil tank assembly 24. The second return oil passage 107 is equipped with a first low-pressure relief valve 17, and the third return oil passage 108 is equipped with a second low-pressure relief valve 21.

[0038] The main return oil passage 105 is also connected to the first return oil passage 106 and the return oil passage that connects to the outlet of the second main relief valve 14. A relief valve (not shown in the figure) is provided at the end of the main return oil passage 105 near the first return oil passage 106. A relief valve (not shown in the figure) is also provided at the end of the main return oil passage 105 near the end of the return oil passage that connects to the outlet of the second main relief valve 14.

[0039] In this embodiment, the lifting proportional valve 12 is a four-position five-way valve. The pilot oil circuit 200, near the lifting proportional valve 12, splits into a first branch 203 and a second branch 204, respectively connecting to the two oil inlets of the lifting proportional valve 12. A third check valve 13 is provided on the first branch 203. One working oil return port of the lifting proportional valve 12 is connected to the control end of the first main valve core 10 via the first connecting oil circuit 301, and the other working oil return port is connected to the control end of the second main valve core 22 via the second connecting oil circuit 302. The return oil port of the lifting proportional valve 12 is connected to the return oil tank assembly 24 via the return oil circuit.

[0040] A relief valve is also connected between the second connecting oil circuit 302 and the return oil circuit of the lifting proportional valve 12. This relief valve and the lifting proportional valve 12 are integrated into a single valve body to form a pilot control valve assembly. The pilot control valve assembly has four connection ports: inlet (IN), return oil (OUT), first control port A (Base), and second control port B (Rod). Pilot oil circuit 200 is distributed inside and outside the pilot control valve assembly via inlet (IN), first connecting oil circuit 301 is distributed inside and outside the pilot control valve assembly via first control port A (Base), second connecting oil circuit 302 is distributed inside and outside the pilot control valve assembly via first control port B (Rod), and return oil circuit is distributed inside and outside the pilot control valve assembly via return oil (OUT).

[0041] The lifting proportional valve 12 includes a lifting position, a lowering position, and a normal position. When the lifting proportional valve 12 is in the lifting position (the rightmost position shown in the figure), the first branch 203 is connected to the first connecting oil passage 301, while the second connecting oil passage 302 and the second branch 204 are both disconnected. When the lifting proportional valve 12 is in the lowering position (the leftmost position shown in the figure), the first branch 203 is connected to the second connecting oil passage 302, while the first connecting oil passage 301 and the second branch 204 are both disconnected. When the lifting proportional valve 12 is in the normal position (the third position from left to right shown in the figure), the pilot oil passage 200 is connected to the return oil passage of the lifting proportional valve 12's return port through the second branch 204, while the first connecting oil passage 301 and the second connecting oil passage 302 are both disconnected.

[0042] In this embodiment, the first one-way throttle valve 5, the second one-way throttle valve 18, the first one-way valve 6, the second one-way valve 16, the first main oil circuit control valve 7, the second main oil circuit control valve 15, the first main relief valve 8, the second main relief valve 14, the first main valve core 10, the second main valve core 22, the first low-pressure relief valve 17, the second low-pressure relief valve 21, the first throttle valve 20, and the second throttle valve 23 are all integrated into a valve body to form a lifting valve assembly.

[0043] Specifically, the lifting valve assembly is equipped with inlet ports P1 and P2, return ports T1, T2, and T3, working ports A and B, and control ports ARod, BBase, PP1, and PP2, which have different functions. Among them, the first sub-oil circuit 101 is distributed inside and outside the lifting valve assembly via inlet port P1, the second sub-oil circuit 102 is distributed inside and outside the lifting valve assembly via inlet port P2, the first return oil circuit 106 is distributed inside and outside the lifting valve assembly via return port T1, the second return oil circuit 107 and the third return oil circuit 108 are distributed inside and outside the lifting valve assembly via two return ports T2 respectively, and the return oil circuit connected to the outlet of the second main relief valve 14 is distributed inside and outside the lifting valve assembly via return port T3. The first connecting oil circuit 301 extends into the lifting valve assembly via control port B Base, and the second connecting oil circuit 302 extends into the lifting valve assembly via control port A Rod. The first pilot oil circuit 4 is distributed inside and outside the lifting valve assembly via control port PP1, and the second pilot oil circuit 19 is distributed inside and outside the lifting valve assembly via control port PP2.

[0044] Figure 2 Please refer to the schematic diagram of the cargo box lifting principle in the lifting speed regulation system of the mining dump truck of the preferred embodiment of this utility model. Figure 2 When the mining dump truck needs to unload, the descent button in the cab is pressed, the lifting speed control system switches to lifting mode, and the lifting proportion valve 12 moves to the lifting position. At this time, the lifting pump 1 starts working, and oil enters the inlet P1 of the lifting valve group from the first sub-oil circuit 101 through the first filter 2, and enters the inlet P2 of the lifting valve group from the second sub-oil circuit 102 through the second filter 3. A portion of the oil inlet P1 serves as pilot oil, flowing through the first pilot sub-oil circuit 4 through the first throttle valve 23 and then out from the control port PP1 to one end of the inlet of the bypass valve 9. At this time, the solenoid of the bypass valve 9 is de-energized, and the bypass valve 9 closes. Simultaneously, the pressure at both ends of the hydraulic pilot control port of the first main oil circuit control valve 7 is equal, the first main oil circuit control valve 7 closes, and the oil in the first sub-oil circuit 101 enters the main oil circuit 100 through the first check valve 6. A portion of the oil at inlet P2 acts as pilot oil, flowing through the first pilot sub-circuit 4, then through the second throttle valve 20, and finally out of control port PP2. The pilot oil flowing from control ports PP1 and PP2 merges and enters the lifting proportional valve 12 at the lifting position via check valve 13. It then enters the hydraulic control terminal of the first main valve core 10 through working port A (Base), building pressure in the right position of the first main valve core 10 and pushing the valve core to the left. The oil in the main circuit 100 merges with the first main valve core 10 at the right position and enters the rodless chamber of the lifting system 11 through working port A of the lifting valve assembly. The oil in the rod chamber of the lifting system 11 is pressurized in the second main valve core 22 through working port B of the lifting valve assembly. Because the oil at the right hydraulic control port flows back to the oil tank assembly 24, the second main valve core 22 moves to the right. The return oil enters the main return oil passage 105 from the second main valve core 22 and then flows back to the oil tank assembly 24 via the second return oil passage 107 and the second return oil passage 108 respectively.

[0045] Figure 3 Please refer to the schematic diagram of the cargo box descent principle in the lifting and speed regulation system of the mining dump truck of the preferred embodiment of this utility model. Figure 3 When the mining dump truck lowers, the lifting speed control system switches to lowering mode, and the lifting proportional valve 12 moves to the lowering position. At this time, the lifting pump 1 starts working, and the oil flows from the first sub-oil circuit 101 through the first filter 2 into the oil inlet P1 of the lifting valve group, and from the second sub-oil circuit 102 through the second filter 3 into the oil inlet P2 of the lifting valve group. A portion of the oil inlet P1 serves as pilot oil, flowing through the first pilot sub-oil circuit 4 through the first throttle valve 23 and then out from the control port PP1 to one end of the bypass valve 9's oil inlet. At this time, the electromagnet of the bypass valve 9 is energized, the valve core moves down, and the pilot oil is unloaded through the bypass oil circuit 103 and then cooled by the cooler 25 of the first return oil circuit 106. Simultaneously, due to the pressure relief at the lower control end of the first main oil circuit control valve 7, the pressure at the upper hydraulic control port is greater than that at the lower hydraulic control port, causing the valve core of the first main oil circuit control valve 7 to move downwards. The oil in the first sub-oil circuit 101 is also unloaded through the first return oil circuit 106 and then cooled by the coolant 25. A small portion of the oil entering the second sub-oil circuit 102 is piloted through the second throttle valve 20, passes through the control port PP2 of the lifting valve assembly, and enters the lowering position of the lifting proportional valve 12. Subsequently, pressure is built up at the control end on the right side of the second main valve core 22, pushing the valve core of the second main valve core 22 to move to the left. Most of the oil in the second sub-oil circuit 102 enters the main oil circuit 100 through the second check valve 16, then passes through the right position of the second main valve core 22, and then flows into the rod chamber of the lifting system 11 through the working oil port B of the lifting valve assembly, beginning its descent. The oil in the rodless chamber of the lifting system 11 enters the lifting valve assembly through the working port A to build up pressure on the left side of the first main valve core 10, pushing the valve core to move to the right. The return oil enters the return main oil passage 105 from the first main valve core 10 and then flows back to the oil tank assembly 24 through the second return oil passage 107 and the second return oil passage 108 respectively.

[0046] The lifting speed control system of this utility model for mining dump truck has the following beneficial effects:

[0047] 1. By adding a bypass valve 9, the oil of one of the pumps of the lifting pump 1 (double gear pump) is unloaded through the first main oil circuit control valve 7, thereby reducing the lifting and lowering speed of the dump truck and preventing the cargo box from falling rapidly. This reduces the impact caused by the cylinder descent to a certain extent, thereby improving the safety and reliability of the system and extending the service life of the cylinder and equipment.

[0048] 2. When the lifting speed control system is in descent mode, the flow rate of oil entering the lifting cylinder is halved, and the remaining oil completely enters the first return oil circuit 106 and is cooled by the cooler 25. The system cooling efficiency is increased, which further improves the service life of the cylinder and equipment.

[0049] This utility model also relates to a mining dump truck, including the aforementioned lifting and speed control system for the mining dump truck. Other structures of this mining dump truck are well known to those skilled in the art and will not be described in detail here.

[0050] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A lifting speed control system for a mining dump truck, characterized in that, Includes a lifting pump (1), a first main oil circuit control valve (7), a bypass valve (9), a first main valve core (10), a second main valve core (22), a lifting proportional valve (12), and an oil tank assembly (24), wherein: The inlet of the lifting pump (1) is connected to the oil tank assembly (24). The two outlets of the lifting pump (1) are connected to the main oil circuit (100) through the first sub-oil circuit (101) and the second sub-oil circuit (102), and then connected to the inlet of the first main valve core (10) and the inlet of the second main valve core (22), respectively. The return ports of the first main valve core (10) and the second main valve core (22) are connected back to the oil tank assembly (24). The outlet of the first main valve core (10) is connected to the rodless chamber of the lifting system (11), and the outlet of the second main valve core (22) is connected to the rod chamber of the lifting system (11). One control end of the first main valve core (10) is connected to one of the working ports of the lifting proportional valve (12), and the other control end of the first main valve core (10) is connected to the oil line between the first main valve core (10) and the lifting system (11); one control end of the second main valve core (22) is connected to the other working port of the lifting proportional valve (12), and the other control end of the second main valve core (22) is connected to the oil line between the second main valve core (22) and the lifting system (11); The pilot oil passage (200) connected to the oil inlet of the lifting proportional valve (12) is divided into a first pilot sub-oil passage (4) and a second pilot sub-oil passage (19) at the end away from the lifting proportional valve (12). The first pilot sub-oil passage (4) is connected to the first sub-oil passage (101), and the second pilot sub-oil passage (19) is connected to the second sub-oil passage (102). The first pilot sub-oil passage (4) is provided with a bypass oil passage (103) that connects back to the oil tank assembly (24), and the bypass oil passage (103) is provided with a bypass valve (9). The inlet of the first main oil circuit control valve (7) is connected to the first sub-oil circuit (101), and the outlet of the first main oil circuit control valve (7) is connected back to the oil tank assembly (24). One of the control terminals of the first main oil circuit control valve (7) is connected to the first sub-oil circuit (101), and the other control terminal of the first main oil circuit control valve (7) is connected to the first pilot sub-oil circuit (4) after passing through the first one-way throttle valve (5).

2. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The oil outlet of the first main oil circuit control valve (7) is connected back to the return oil tank assembly (24) through the first return oil circuit (106), and a cooler (25) is provided on the first return oil circuit (106); the bypass oil circuit (103) is connected to the first return oil circuit (106) at the end away from the first pilot sub-oil circuit (4).

3. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The first pilot sub-oil circuit (4) is provided with a first throttle valve (23) at the end near the first sub-oil circuit (101), and the second pilot sub-oil circuit (19) is provided with a second throttle valve (20) at the end near the second sub-oil circuit (102).

4. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, It also includes a second main oil circuit control valve (15), the oil inlet of the second main oil circuit control valve (15) is connected to the second sub-oil circuit (102), the oil outlet of the second main oil circuit control valve (15) is connected back to the oil tank assembly (24), one of the control terminals of the second main oil circuit control valve (15) is connected to the second sub-oil circuit (102), and the other control terminal of the second main oil circuit control valve (15) is connected to the second pilot sub-oil circuit (19) of the second main oil circuit control valve (15) after passing through the second one-way throttle valve (18).

5. The lifting and speed control system for a mining dump truck as described in claim 4, characterized in that, It also includes a first main relief valve (8) connected in parallel with the first main oil circuit control valve (7), and a second main relief valve (14) connected in parallel with the second main oil circuit control valve (15).

6. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The first sub-oil circuit (101) is equipped with a first filter (2), and the second sub-oil circuit (102) is equipped with a second filter (3).

7. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The main oil circuit (100) is provided with a first check valve (6) at the end near the first sub-oil circuit (101), and the main oil circuit (100) is provided with a second check valve (16) at the end near the second sub-oil circuit (102).

8. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The return port of the first main valve core (10) and the return port of the second main valve core (22) are both connected to the main return oil circuit (105). The main return oil circuit (105) is connected to a second return oil circuit (107) and a third return oil circuit (108) that are connected to the oil tank assembly (24). The second return oil circuit (107) is provided with a first low-pressure relief valve (17), and the third return oil circuit (108) is provided with a second low-pressure relief valve (21).

9. The lifting and speed control system for a mining dump truck as described in claim 1, characterized in that, The pilot oil circuit (200) near the lifting proportional valve (12) is divided into a first branch (203) and a second branch (204), which are respectively connected to the two oil inlets of the lifting proportional valve (12). A third check valve (13) is provided on the first branch (203). One of the working oil returns of the lifting proportional valve (12) is connected to the control end of the first main valve core (10) through the first connecting oil circuit (301). The other working oil returns of the lifting proportional valve (12) is connected to the control end of the second main valve core (22) through the second connecting oil circuit (302). The return oil port of the lifting proportional valve (12) is connected to the return oil tank assembly (24). The lifting proportional valve (12) includes a lifting position, a lowering position, and a normal position; when the lifting proportional valve (12) is in the lifting position, the first branch (203) is connected to the first connecting oil line (301); when the lifting proportional valve (12) is in the lowering position, the first branch (203) is connected to the second connecting oil line (302); when the lifting proportional valve (12) is in the normal position, the second branch (204) is connected to the return oil port of the lifting proportional valve (12).

10. A mining dump truck, characterized in that, Including the lifting speed control system of the mining dump truck as described in any one of claims 1-9.

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