Main push loop control system and method for mining shield tunneling machine and mining shield tunneling machine

Abstract

The invention relates to a main push loop control system and method for a mining shield tunneling machine and the mining shield tunneling machine. The mining shield tunneling machine comprises a cutterhead, a driving part and a supporting shield, the driving part and the supporting shield are connected through a plurality of main pushing oil cylinders, the main pushing oil cylinders are divided into a plurality of areas controlled by different main pushing loops, and the main pushing loop control system comprises a load sensitive system, a main pushing loop control system and a main pushing loop control system, the load sensitive system is used for controlling the output pressure and the output flow of a hydraulic pump of the main push loop control system through the feedback pressure of each main push loop and the opening amount of a proportional multi-way valve. The proportional multi-way valve is used for respectively controlling the speed of the main push oil cylinder; and the proportional overflow valve and the proportional multi-way valve cooperate to be used for achieving pressure control over all the areas. By adopting the load sensitive control loop, the system pressure can be changed according to the size of the load.

Description

Technical Field

[0001] The present invention relates to the technical field of mining shield machines; in particular, the present invention relates to a main propulsion circuit control system and method for a mining shield machine and a mining shield machine. Background Art

[0002] Currently, the hydraulic system for the main propulsion cylinder control circuit of mining shield tunneling machines is essential and crucial during construction. Most main propulsion circuit control systems for municipal and pipeline tunneling shield machines offer dual control circuits: pressure and flow. This control method is essential for shield equipment and is often implemented using proportional flow valves and proportional pressure reducing valves. Summary of the Invention

[0003] In view of this, the present invention provides a main propulsion circuit control system, method and mining shield machine for a mining shield machine, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0004] To achieve the aforementioned objectives, a first aspect of the present invention provides a main thrust circuit control system for a mining shield machine, the mining shield machine comprising a cutterhead, a drive unit, and a support shield, the drive unit and the support shield being connected by a plurality of main thrust cylinders, the main thrust cylinders being divided into a plurality of zones controlled by different main thrust circuits, wherein the main thrust circuit control system comprises: A load sensing system for controlling the output pressure and output flow of the hydraulic pump of the main push circuit control system through the feedback pressure of each main push circuit and the opening amount of the proportional multi-way valve; A proportional multi-way valve, the proportional multi-way valve is used to control the speed of the main push cylinder respectively; and A proportional relief valve is provided, wherein the proportional relief valve and the proportional multi-way valve cooperate to realize pressure control of each of the areas.

[0005] In the main push circuit control system as described above, optionally, the number of the main push cylinders is 10, and the multiple areas include an upper area, a lower area, a left area and a right area, wherein the upper area is provided with a group of two main push cylinders in parallel, the lower area is provided with a group of four main push cylinders in parallel, the left area is provided with a group of two main push cylinders in parallel, and the right area is provided with a group of two main push cylinders in parallel.

[0006] In the main push circuit control system as described above, stroke sensors are optionally arranged at each of the areas. When it is necessary to achieve synchronous flow control of each main push cylinder, the stroke sensor feeds back the displacement stroke of the main push cylinder in each area. After the processor of the main push circuit control system compares the target value and the actual value of the displacement stroke, it controls the opening degree of the proportional multi-way valve in each area by controlling the proportional solenoid of the proportional multi-way valve to achieve synchronous stroke closed-loop control of each area.

[0007] In the main push circuit control system as described above, optionally, the proportional multi-way valve includes a first valve, a second valve, a third valve and a fourth valve, the first valve, the second valve, the third valve and the fourth valve are connected to the oil supply pipeline of the main push circuit control system, the first valve is connected to and controls the main push cylinder in the lower area, the second valve is connected to and controls the main push cylinder in the left area, the third valve is connected to and controls the main push cylinder in the right area, and the fourth valve is connected to and controls the main push cylinder in the upper area; and The main push circuit control system also includes a control valve group corresponding to each plate valve, and the control valve group is respectively arranged between each group of main push cylinders and plate valves. Each control valve group includes a balancing valve, a one-way valve and a shuttle valve, and a pressure sensor is connected to the shuttle valve.

[0008] In the main propulsion circuit control system as described above, optionally, each control valve group includes two balancing valves, two one-way valves and one shuttle valve, and the shuttle valve is connected between the rodless chamber and the rod chamber of the oil cylinder in each zone.

[0009] In the main push circuit control system as described above, optionally, the load-sensing system includes a load-sensing pump and a load-sensing valve, the load-sensing pump is the hydraulic pump, and a shuttle valve is arranged between the load-sensing system and the proportional multi-way valve. The main push circuit control system senses the feedback pressure of each main push circuit through the shuttle valve, feeds back the maximum pressure of all main push circuits to the control device of the load-sensing pump, and controls the output pressure of the load-sensing pump.

[0010] In the main push circuit control system as described above, optionally, the load-sensitive system further includes a first variable cylinder, a second variable cylinder and a pressure cut-off valve, the right end of the load-sensitive valve is connected to the oil outlet of the load-sensitive pump, and the left end of the load-sensitive valve passes through the proportional multi-way valve; the rodless chamber of the first variable cylinder is connected to the oil outlet, and the rodless chamber of the second variable cylinder is connected to the load-sensitive valve, and the pistons of the first variable cylinder and the second variable cylinder are both connected to the swash plate of the load-sensitive pump, and the displacement of the load-sensitive pump is controlled by adjusting the inclination angle of the swash plate; the pressure cut-off valve adjusts its set pressure through a hard spring to adjust the displacement of the load-sensitive pump. When the pressure in the main push circuit reaches or exceeds the set pressure, the pressure cut-off valve is used to connect the rodless chamber of the second variable cylinder and the oil outlet to reduce the displacement of the load-sensitive pump.

[0011] In the main push circuit control system as described above, optionally, the proportional relief valve is a flameproof proportional pressure relief valve, the flow of the flameproof proportional pressure relief valve is smaller than the flow of the proportional multi-way valve, and the flameproof proportional pressure relief valve is used to directly control the pressure difference of the pressure compensation circuit of the proportional multi-way valve.

[0012] To achieve the aforementioned objectives, a second aspect of the present invention provides a mining shield machine comprising a main propulsion circuit control system as described in any one of the first aspects.

[0013] To achieve the aforementioned objectives, a third aspect of the present invention provides a control method for a main propulsion circuit control system for a mining shield machine as described in any one of the first aspects, wherein the method comprises: Step I: Set the pressure of the proportional relief valve of the main push cylinder in the target area to be greater than the pressure of the proportional relief valve of the main push cylinder in other areas; Step II: opening all the proportional multi-way valves, intentionally increasing the current of the proportional multi-way valve of the main push cylinder in the target area, and observing the pressure value of the pressure sensor of the main push circuit in the target area. When the pressure value of the pressure sensor of the main push circuit in the target area reaches the set pressure, the compensation pressure of the pressure compensation valve of the proportional multi-way valve in the target area is reduced, so that the flow rate of the proportional multi-way valve in the target area is reduced when the opening is the same; and Step III: When the pressure in the target area drops but does not reach the set value of the proportional relief valve, the compensation pressure of the pressure compensation valve increases, and the flow of the proportional multi-way valve in the target area increases to achieve the set pressure value, so that the pressure of the main push cylinder in the target area is greater than the pressure of the main push cylinder in other areas.

[0014] The technical solution of the present invention adopts a load-sensitive control circuit, which can realize that the system pressure changes according to the size of the load.

[0015] In an optional technical solution, the system flow rate varies based on the opening size of the proportional reversing valve, effectively improving the efficiency of the hydraulic system and reducing energy loss. In a further optional technical solution, a proportional multi-way valve is used to control the speed of each zone cylinder. The explosion-proof proportional multi-way valve is compact, space-saving, and affordable for use in underground coal mines, making it easy to achieve synchronous flow control of multiple cylinders. In an even more advanced technical solution, a proportional relief valve is used to control the pressure of a single circuit of the proportional multi-way valve, achieving pressure control of the main push circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure of the present invention will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 A schematic diagram of an embodiment of a mining shield machine according to the present invention; Figure 2 for Figure 1 Schematic diagram of the group distribution of the main thrust cylinders of a shield machine used in a mine; and Figure 3 Schematic diagram of a main propulsion circuit control system for a mining shield machine according to the present invention.

[0017] Figure numerals: 1-mining shield machine; 2-main propulsion circuit control system; 3-cutterhead; 4-drive unit; 5-support shield; 6-main propulsion cylinder; 7-proportional multi-way valve; 8-proportional relief valve; 9-upper zone; 10-lower zone; 11-left zone; 12-right zone; 13-load sensing pump; 14-pressure cut-off valve; 15-shuttle valve; 16-stroke sensor; 17-first variable cylinder; 18-second variable cylinder; 19-load sensing valve; 20-swash plate; 21-balancing valve; 22-check valve; 23-shuttle valve; 24-pressure sensor; 25-pressure compensation valve. DETAILED DESCRIPTION

[0018] With reference to the accompanying drawings and specific embodiments, the main propulsion circuit control system, method, and structure, composition, characteristics, and advantages of a mining shield machine of the present invention will be described below in an exemplary manner. However, all descriptions should not be used to limit the present invention in any way.

[0019] In addition, for any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature shown or implied in the drawings, the present invention still allows for continued arbitrary combination or deletion between these technical features (or their equivalents) without any technical obstacles, and thus it should be considered that these more embodiments according to the present invention are also within the scope of the description in this document.

[0020] Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Thus, a feature specified as "first," "second," "third," or "fourth" may explicitly or implicitly include at least one of these features.

[0021] A mining shield machine is a large-scale construction equipment designed and manufactured specifically for the excavation of mining roadways or tunnels.

[0022] Figure 1 Schematic diagram of an embodiment of a mining shield machine according to the present invention.

[0023] As shown in the figure, in this illustrated example, the mining shield machine 1 may include a cutterhead 3, a drive unit 4 and a support shield 5. The drive unit 4 and the support shield 5 are connected by a plurality of main thrust cylinders 6. The cutterhead 3 is located at the front end of the mining shield machine 1 and is used for cutting and crushing mineral rock. The cutterhead is usually disc-shaped and has different opening rates, tool layouts and rotation modes depending on the mineral deposit conditions. The support shield 5 is arranged on the outside of the mining shield machine 1 to provide temporary support and support for the propulsion reaction force. The drive unit 4 is used to push the mining shield machine 1 forward and provide thrust to the cutterhead 3. The propulsion of the drive unit 4 is provided by a plurality of main thrust cylinders 6.

[0024] The mining shield machine 1 may further include a slag discharge system, a rear supporting system, a guide system, a ventilation and dust removal system, a guide system, etc., which will not be described in detail here.

[0025] Figure 2 for Figure 1 Schematic diagram of the group distribution of the main thrust cylinders of a shield machine used in mining.

[0026] As can be seen from the figure, in the illustrated example, the number of the main push cylinders 6 of the mining shield machine is 10. These main push cylinders 6 are divided into a plurality of areas controlled by different main push circuits. These multiple areas include an upper area 9, a lower area 10, a left area 11 and a right area 12, wherein the upper area 9 is provided with a group of two main push cylinders in parallel, the lower area 10 is provided with a group of four main push cylinders in parallel, the left area 11 is provided with a group of two main push cylinders in parallel, and the right area 12 is provided with a group of two main push cylinders in parallel. According to the illustrated embodiment, the control of the main push circuit needs to achieve stroke synchronization of the four groups of main push cylinders or pressure control of the four areas. In addition, as shown in the figure, the arrangement of the main push cylinders in each group is symmetrical with respect to the horizontal or vertical radial line passing through it. In the illustrated example, each main push cylinder is also optionally exemplified as being arranged at the peripheral edge position of the drive unit 4.

[0027] In different embodiments, other numbers of main propulsion cylinders may be selected, and other numbers and arrangements may be used to divide the areas.

[0028] Figure 3 This diagram shows a main thrust circuit control system for a mining shield machine according to the present invention. As shown, the system comprises a load-sensing pump, a load-sensing valve, a proportional relief valve, a balancing valve, a check valve, a shuttle valve, a pressure sensor, a main thrust cylinder, a stroke sensor, a pressure compensation valve, and a proportional multi-way valve.

[0029] As shown in the figure, the main propulsion circuit control system 2 for the mining shield machine 1 may include a load sensing system, a proportional multi-way valve 7 and a proportional relief valve 8.

[0030] The load-sensing system controls the output pressure and flow of the hydraulic pump in the main propulsion circuit control system by using the feedback pressure of each main propulsion circuit and the opening of the proportional multi-way valve. A load-sensing pump and load-sensing valve combination implements a load-sensing system. The main propulsion circuit control system senses the feedback pressure of each main propulsion circuit through a shuttle valve. The maximum pressure of all circuits is fed back to the hydraulic pump, directly controlling the pump's output pressure, thereby achieving load-dependent system pressure. This configuration of the main propulsion circuit control system saves energy and improves system efficiency.

[0031] The proportional multi-way valve 7 is used to control the speed of the main push cylinder 6 separately. The proportional multi-way valve 7 can be composed of multiple plate valves, which can control multiple main push cylinders simultaneously or independently. The proportional multi-way valve is used to control the speed of each main push cylinder, which can achieve synchronous control of the flow of the main push cylinders in each area. As shown in the figure, the main push cylinder can be divided into four groups of upper, lower, left and right areas. Stroke sensors are arranged in each area. When the synchronous control of the flow of the four groups of main push cylinders is to be achieved, the displacement stroke of each area is fed back by the stroke sensor. After the processor compares the target value with the actual value, it controls the opening degree of the four-zone multi-way valve by controlling the proportional solenoid of the proportional multi-way valve to achieve stroke closed-loop control, and finally achieve synchronous control of each zone.

[0032] The proportional relief valve 8 and the proportional multi-way valve 7 work together to achieve pressure control in each area. The proportional relief valve 8 can be used to limit the maximum pressure of the system. When the system pressure reaches or exceeds the set value, the valve port opens to divert the oil to the tank, thereby stabilizing the system pressure near the set value. Proportional relief valves and proportional multi-way valves are used to achieve pressure control in each area, so that the pressure control uses a small-flow explosion-proof proportional pressure relief valve to directly control the pressure difference of the pressure compensation circuit of the proportional multi-way valve. The benefits of such a setting include at least: using a small-flow pressure control valve to directly pilot control the maximum output pressure of the large-flow main valve; the explosion-proof proportional relief valve has high control accuracy and fast response speed, and can achieve stepless pressure regulation.

[0033] As shown in the figure, stroke sensors 16 are arranged in each area. When it is necessary to achieve synchronous flow control of each main push cylinder 6, the stroke sensor 16 will feedback the displacement stroke of the main push cylinder 6 in each area. After the processor of the main push circuit control system 2 compares the target value and the actual value of the displacement stroke, it controls the proportional solenoid of the proportional multi-way valve 7 to control the opening degree of the proportional multi-way valve 7 in each area to achieve synchronous stroke closed-loop control of each area.

[0034] Although the diagram shows that only one stroke sensor is set for each area, in an optional embodiment, a stroke sensor can be set for the main push cylinder of each area separately, and the displacement stroke of all the main push cylinders in the corresponding area can be comprehensively considered during control.

[0035] Furthermore, as can be seen from the figure, the proportional multi-way valve 7 can include a first valve, a second valve, a third valve, and a fourth valve, each of which is equipped with corresponding proportional solenoids B7, B3, B5, and B1, respectively. The first, second, third, and fourth valves are connected to the oil supply line of the main propulsion circuit control system 2. The fourth valve is connected to and controls the main propulsion cylinder in the upper zone 9, the second valve is connected to and controls the main propulsion cylinder in the left zone 11, the third valve is connected to and controls the main propulsion cylinder in the right zone 12, and the first valve is connected to and controls the main propulsion cylinder in the lower zone 10.

[0036] As shown in the figure, the main propulsion circuit control system 2 can also include a control valve group corresponding to each flap valve. The control valve group is respectively arranged between each group of main propulsion cylinders and the flap valves. Each control valve group includes a balancing valve 21, a check valve 22, and a shuttle valve 23. The shuttle valve 23 is connected to a pressure sensor 24. Each control valve group includes two balancing valves 21, two check valves 22, and a shuttle valve 23. The shuttle valve 23 is connected between the rodless chamber and the rod chamber of each zone cylinder through the two check valves 22. Here, the check valve 22 plays a role in replenishing oil, preventing the internal forces of multiple cylinders from causing the cylinders to be sucked empty. It also avoids the formation of negative pressure in the rodless chamber due to insufficient oil supply when the rod chamber is draining oil and the rodless chamber is absorbing oil.

[0037] The load sensing system is further described below with reference to the accompanying drawings.

[0038] The load-sensing system can include a load-sensing pump 13 and a load-sensing valve 19. The load-sensing pump 13 can be a hydraulic pump. A shuttle valve 15 is provided between the load-sensing system and the proportional multi-way valve 7. The main propulsion circuit control system 2 senses the feedback pressure of each main propulsion circuit through the shuttle valve 15, feeds back the maximum pressure of all main propulsion circuits to the control device of the load-sensing pump 13, and controls the output pressure of the load-sensing pump 13.

[0039] As shown in the figure, the load-sensing system further includes a first variable displacement cylinder 17, a second variable displacement cylinder 18, and a pressure cut-off valve 14. The right end of the load-sensing valve 19 is connected to the oil outlet of the load-sensing pump 13, while the left end of the load-sensing valve 19 is connected via a proportional multi-way valve 7. The rodless chamber of the first variable displacement cylinder 17 is connected to the oil outlet, while the rodless chamber of the second variable displacement cylinder 18 is connected to the load-sensing valve 19. The pistons of both the first and second variable displacement cylinders 17 and 18 are connected to the swash plate 20 of the load-sensing pump 13. Adjusting the inclination of the swash plate 20 controls the displacement of the load-sensing pump 13. The pressure cut-off valve 14 has a set pressure adjusted by a stiff spring to regulate the displacement of the load-sensing pump 13. When the pressure in the main propulsion circuit reaches or exceeds the set pressure, the pressure cut-off valve 14 connects the rodless chamber of the second variable displacement cylinder 18 to the oil outlet, reducing the displacement of the load-sensing pump 13.

[0040] The proportional relief valve 8 is a flameproof proportional pressure relief valve. The flow rate of the flameproof proportional pressure relief valve is smaller than the flow rate of the proportional multi-way valve 7. The flameproof proportional pressure relief valve is used to directly control the pressure difference of the pressure compensation circuit of the proportional multi-way valve 7.

[0041] The aforementioned embodiment of the underground mining shield machine of the present invention utilizes a load-sensing control system to achieve both stroke synchronization and pressure control of the four zones of the main hydraulic circuit, effectively improving hydraulic system efficiency and reducing energy loss. A combined explosion-proof proportional multi-way valve and pilot proportional pressure control method achieves stepless automatic control of the single-circuit pressure of each zone's cylinder.

[0042] Understandably, based on Figure 3 Each embodiment of the main propulsion loop control system described in detail can be applied to Figure 1 Mining shield machine 1.

[0043] The present invention also relates to a control method for a main propulsion circuit control system 2 of a mining shield machine 1 as described in any of the aforementioned embodiments. The method may include the following steps I to III.

[0044] In step I, the pressure of the proportional relief valve of the main push cylinder in the target area is set to be greater than the pressure of the proportional relief valve of the main push cylinder in other areas.

[0045] In step II, all proportional multi-way valves are opened, wherein the current of the proportional multi-way valve of the main push cylinder in the target area is consciously increased, and the pressure value of the pressure sensor of the main push circuit in the target area is observed. When the pressure value of the pressure sensor of the main push circuit in the target area reaches the set pressure, the compensation pressure of the pressure compensation valve 25 of the proportional multi-way valve in the target area is reduced, so that the flow rate of the proportional multi-way valve in the target area is reduced under the same opening.

[0046] In step III, when the pressure in the target area drops but does not reach the set value of the proportional relief valve, the compensation pressure of the pressure compensation valve increases, and the flow of the proportional multi-way valve in the target area increases to achieve the set pressure value, so that the pressure of the main push cylinder in the target area is greater than the pressure of the main push cylinder in other areas.

[0047] Specifically, taking the upper zone pressure control as an example, assuming the upper zone pressure is higher than the pressures in other zones, first set the pressure of the upper zone cylinder explosion-proof proportional relief valve to be higher than the pressures of the other zones' explosion-proof proportional relief valves. Once this is achieved, open the proportional multi-way valve, intentionally increasing the current flowing through the corresponding upper zone proportional multi-way valve. As the engine advances, the upper zone pressure will rise further. Observe the pressure sensor's pressure reading. When the set pressure is reached, the compensation pressure of the pressure compensating valve in the upper zone proportional multi-way valve will decrease, resulting in a lower flow rate for the same opening. When the upper zone pressure drops, meaning it falls below the set value of the proportional relief valve, the compensation pressure of the pressure compensating valve will increase, increasing the flow rate in that zone to achieve the set pressure, thus ensuring that the upper zone pressure is higher than the pressures in other zones. This circuit achieves pressure control in each zone in this manner.

[0048] Taking all the above aspects into consideration, the embodiments of the present invention can realize one or more of the following functions: adopting a load-sensitive control circuit to realize that the system pressure changes according to the size of the load. The system flow changes according to the opening size of the proportional reversing valve. It effectively improves the efficiency of the hydraulic system and reduces energy loss; adopts a proportional multi-way valve to control the speed of the oil cylinders in each zone. The explosion-proof proportional multi-way valve is widely used in coal mines. It has a compact structure, occupies a small space and is affordable. It is easy to realize synchronous flow control of multiple cylinders; adopting a proportional overflow valve to perform single-way pressure control of the proportional multi-way valve can realize pressure control of the main push circuit.

[0049] In a further embodiment of the present invention, a mining shield machine main thrust control system can utilize a wide range of valve groups, minimizing space and significantly improving system efficiency. Furthermore, underground applications can utilize a wide selection of hydraulic valves and explosion-proof proportional valve models and specifications; the control valve group occupies minimal space and saves costs; and the control system generates less heat and achieves higher efficiency.

[0050] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical concept of the present invention, and these deformations and modifications should all fall within the scope of the present invention.

Claims

1. A main thrust circuit control system (2) for a mining shield machine (1), wherein the mining shield machine (1) comprises a cutterhead (3), a drive unit (4) and a support shield (5), wherein the drive unit (4) and the support shield (5) are connected by a plurality of main thrust cylinders (6), and the main thrust cylinders (6) are divided into a plurality of areas controlled by different main thrust circuits, characterized in that: The main propulsion loop control system (2) comprises: A load sensing system for controlling the output pressure and output flow of the hydraulic pump of the main push circuit control system through the feedback pressure of each main push circuit and the opening amount of the proportional multi-way valve; A proportional multi-way valve (7), the proportional multi-way valve (7) is used to control the speed of the main push cylinder (6) respectively; and A proportional overflow valve (8) is provided. The proportional overflow valve (8) and the proportional multi-way valve (7) cooperate to realize pressure control of each of the areas.

2. The main propulsion loop control system (2) according to claim 1, characterized in that: The number of the main push cylinders (6) is 10, and the multiple areas include an upper area (9), a lower area (10), a left area (11) and a right area (12), wherein the upper area (9) is provided with a group of two main push cylinders connected in parallel, the lower area (10) is provided with a group of four main push cylinders connected in parallel, the left area (11) is provided with a group of two main push cylinders connected in parallel, and the right area (12) is provided with a group of two main push cylinders connected in parallel.

3. The main propulsion loop control system (2) according to claim 2, characterized in that: A stroke sensor (16) is arranged at each of the areas. When it is necessary to achieve synchronous flow control of each main push cylinder (6), the stroke sensor (16) feeds back the displacement stroke of the main push cylinder (6) in each area. After the processor of the main push circuit control system (2) compares the target value and the actual value of the displacement stroke, the proportional electromagnet of the proportional multi-way valve (7) is controlled to control the opening degree of the proportional multi-way valve (7) in each area to achieve synchronous stroke closed-loop control of each area.

4. The main propulsion loop control system (2) according to claim 2, characterized in that: The proportional multi-way valve (7) includes a first valve, a second valve, a third valve and a fourth valve, wherein the first valve, the second valve, the third valve and the fourth valve are connected to the oil supply pipeline of the main push circuit control system (2), the fourth valve is connected to and controls the main push oil cylinder at the upper zone (9), the second valve is connected to and controls the main push oil cylinder at the left zone (11), the third valve is connected to and controls the main push oil cylinder at the right zone (12), and the first valve is connected to and controls the main push oil cylinder at the lower zone (10); and The main propulsion circuit control system (2) further includes a control valve group corresponding to each plate valve, wherein the control valve group is respectively arranged between each group of main propulsion oil cylinders and the plate valve, and each control valve group includes a balance valve (21), a one-way valve (22) and a shuttle valve (23), and a pressure sensor (24) is connected to the shuttle valve (23).

5. The main propulsion loop control system (2) according to claim 4, characterized in that: Each control valve group comprises two balancing valves (21), two one-way valves (22) and one shuttle valve (23), and the shuttle valve (23) is connected between the rodless chamber and the rod chamber of the oil cylinder in each zone.

6. The main propulsion loop control system (2) according to claim 1, characterized in that: The load-sensing system includes a load-sensing pump (13) and a load-sensing valve (19), wherein the load-sensing pump (13) is the hydraulic pump, and a shuttle valve (15) is provided between the load-sensing system and the proportional multi-way valve (7). The main push circuit control system (2) senses the feedback pressure of each main push circuit through the shuttle valve (15), feeds back the maximum pressure of all main push circuits to the control device of the load-sensing pump (13), and controls the output pressure of the load-sensing pump (13).

7. The main propulsion loop control system (2) according to claim 6, characterized in that: The load sensing system further comprises a first variable cylinder (17), a second variable cylinder (18) and a pressure cut-off valve (14); the right end of the load sensing valve (19) is connected to the oil outlet of the load sensing pump (13); the left end of the load sensing valve (19) is connected through the proportional multi-way valve (7); the rodless chamber of the first variable cylinder (17) is connected to the oil outlet, the rodless chamber of the second variable cylinder (18) is connected to the load sensing valve (19), and the first variable cylinder (17) and the second variable cylinder (18) are connected. The pistons of the second variable cylinder (18) and the second variable cylinder (18) are connected to the swash plate (20) of the load-sensing pump (13), and the displacement of the load-sensing pump (13) is controlled by adjusting the inclination angle of the swash plate (20); the pressure cut-off valve (14) adjusts its set pressure through a hard spring to adjust the displacement of the load-sensing pump (13); when the pressure in the main push circuit reaches or exceeds the set pressure, the pressure cut-off valve (14) is used to connect the rodless chamber of the second variable cylinder (18) and the oil outlet, thereby reducing the displacement of the load-sensing pump (13).

8. The main propulsion loop control system (2) according to claim 1, characterized in that: The proportional relief valve (8) is a flameproof proportional pressure relief valve, the flow rate of which is smaller than the flow rate of the proportional multi-way valve (7), and the flameproof proportional pressure relief valve is used to directly control the pressure difference of the pressure compensation circuit of the proportional multi-way valve (7).

9. A mining shield machine (1) comprising the main propulsion circuit control system (2) according to any one of claims 1 to 8.

10. A control method for a main propulsion circuit control system (2) for a mining shield machine (1) according to any one of claims 1 to 8, characterized in that: The method comprises: Step I: Set the pressure of the proportional relief valve of the main push cylinder in the target area to be greater than the pressure of the proportional relief valve of the main push cylinder in other areas; Step II: opening all the proportional multi-way valves, intentionally increasing the current of the proportional multi-way valve of the main push cylinder in the target area, and observing the pressure value of the pressure sensor of the main push circuit in the target area. When the pressure value of the pressure sensor of the main push circuit in the target area reaches the set pressure, the compensation pressure of the pressure compensation valve of the proportional multi-way valve in the target area is reduced, so that the flow rate of the proportional multi-way valve in the target area is reduced when the opening is the same; and Step III: When the pressure in the target area drops but does not reach the set value of the proportional relief valve, the compensation pressure of the pressure compensation valve increases, and the flow of the proportional multi-way valve in the target area increases to achieve the set pressure value, so that the pressure of the main push cylinder in the target area is greater than the pressure of the main push cylinder in other areas.

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