A multiple filtering device for hydraulic oil of a shield machine

Abstract

The utility model relates to shield machine hydraulic oil filtration technical field, concretely is a kind of shield machine hydraulic oil multiple filtration device, including oil tank and filter structure, and filter structure is connected with the lateral outside of oil tank and is communicated, filter structure includes base body, valve body subassembly and filter subassembly, and T-shaped structure board is fixedly installed in base body to be separated and form the buffer cavity located in upper portion and the filter cavity located below and left-right symmetry, and T-shaped structure board is located above the two side filter cavities and is respectively equipped with inlet, and valve body subassembly is installed at inlet, and filter subassembly is installed in filter cavity, and the dismounting of filter subassembly lifts or closes valve body subassembly;The mode switching of alternate filtration and synchronous filtration can be flexibly adapted to pollution load, and the filtration efficiency is improved;The problem that shield machine hydraulic oil filtration is difficult to consider filtration efficiency and construction continuity is solved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic oil filtration technology for tunnel boring machines, specifically a multi-stage filtration device for hydraulic oil in tunnel boring machines. Background Technology

[0002] As the core equipment for underground engineering excavation, the stable operation of the hydraulic system of a tunnel boring machine (TBM) directly determines construction efficiency and equipment lifespan. The cleanliness of the hydraulic oil is a crucial prerequisite for ensuring the normal operation of the precision components of the hydraulic system. Because TBMs operate for extended periods in complex geological formations rich in sand, dust, and rock debris, solid impurities easily mix into the hydraulic oil during circulation. If these impurities are not filtered promptly and efficiently, they will not only accelerate the wear of hydraulic components and cause valve jamming and other malfunctions, but also lead to unstable system pressure. In severe cases, this can even cause equipment shutdown, delaying the construction schedule and increasing high maintenance costs.

[0003] Tunnel boring machines (TBMs) need to operate in various geological formations, including clay, gravel, and weathered rock. The pollution load varies significantly between these formations. For example, in low-pollution formations like clay, the particles are extremely fine and don't easily generate large amounts of loose debris during TBM excavation, resulting in low impurity content and fine particles in the hydraulic oil. However, in highly polluted formations like gravel and fractured rock, the hydraulic oil contains a large amount of rock debris, metal abrasive particles, and other large particles, easily clogging the filter components and leading to substandard hydraulic oil cleanliness. This accelerates the wear of precision components such as hydraulic pumps and valves, and can even cause valve jamming and system pressure instability. Existing TBM hydraulic oil filtration systems struggle to balance filtration efficiency with construction continuity. When facing low-pollution formations where impurities are less likely to enter, the low impurity content in the hydraulic oil results in redundant filtration efficiency. However, when facing highly polluted formations, the filtration system is easily clogged or damaged by large particles during thorough filtration, requiring extended downtime for maintenance or cleaning.

[0004] Therefore, this utility model provides a multi-stage filtration device for hydraulic oil in tunnel boring machines to solve the above-mentioned problems. Utility Model Content

[0005] The technical problem to be solved by this utility model is that the existing hydraulic oil filtration system for tunnel boring machines is difficult to balance filtration efficiency and construction continuity.

[0006] This utility model provides the following technical solution: a multi-stage filtration device for hydraulic oil in a tunnel boring machine, comprising an oil tank and a filtration structure. The filtration structure is externally connected to the side of the oil tank. The filtration structure includes a base, a valve body assembly, and a filter assembly. A T-shaped structural plate is fixedly installed inside the base, thereby separating an upper buffer chamber and a lower, symmetrically positioned filter chamber. The T-shaped structural plate has inlets above the two filter chambers on either side, and valve body assemblies are installed at these inlets. Filter assemblies are installed inside the filter chambers. The removal or installation of the filter assembly raises or closes the valve body assembly. The two symmetrical filter chambers and filter assemblies can perform filtration synchronously, thereby improving filtration efficiency; or they can perform filtration asynchronously and alternately, thus maintaining operation during cleaning and maintenance of the filter assembly. Furthermore, the switching between alternating and synchronous filtration modes can flexibly adapt to the pollution load and improve filtration efficiency.

[0007] As one of the preferred embodiments of this disclosure, the valve body assembly includes a damping rod, a base plate, a connecting rod, and a sealing body. The damping rod is fixedly installed at the bottom of the inlet of the T-shaped structural plate, the other end of the damping rod is fixedly installed at the base plate, the middle upper part of the base plate is fixedly installed at the connecting rod, and the other end of the connecting rod is fixedly installed at the sealing body.

[0008] As one of the preferred embodiments of this disclosure, the filter assembly includes a housing, an outer filter body, a mounting ring, and a base ring. The housing has a cylindrical structure with multiple openings on its circumferential surface. The outer filter body is fixedly installed within each opening. A mounting ring is fixedly installed on the outer circumferential surface of the bottom of the housing. An integrated base ring is fixedly attached to the filter cavity. After the base ring and the mounting ring are tightly fitted together, the top end face of the housing abuts against the base plate and presses against the damping rod. During installation, the filter assembly lifts the sealing body to allow hydraulic oil to flow in. During disassembly, the sealing body blocks the inlet to prevent hydraulic oil from entering, thus automatically sealing off the inlet and preventing hydraulic oil from entering during disassembly and cleaning of the filter assembly. This ensures rapid disassembly and improves efficiency while preventing hydraulic oil leakage and contamination during disassembly, maintenance, and cleaning.

[0009] As a preferred embodiment of this disclosure, an inner filter is fixedly installed inside the outer casing, and the inner diameter of the mounting ring is smaller than the inner diameter of the inner filter. This enables multi-stage filtration, improving filtration efficiency and accuracy, thereby ensuring that the hydraulic oil used by the tunnel boring machine is free of impurities and better adapting to the complex requirements of high pressure, continuous operation, and multiple contaminants.

[0010] As one of the preferred embodiments of this disclosure, the sealing body and the inlet are in a mutually cooperating frustum-shaped structure. The built-in guiding function facilitates a better fit and improves sealing performance while achieving high-pressure self-tightening sealing, which helps to enhance sealing and prevent hydraulic oil leakage.

[0011] As one of the preferred embodiments of this disclosure, a bottom filter body is fixedly installed on the inner circumferential surface of the mounting ring.

[0012] As one of the preferred embodiments of this disclosure, the pore sizes of the inner filter, outer filter, and bottom filter decrease sequentially.

[0013] The beneficial effects of this utility model are as follows: 1. In this utility model, when the filter assembly is installed, the outer shell can lift the base plate to overcome the elastic force of the damping rod, thereby causing the closed body to move upward and open the inlet to allow hydraulic oil to enter. Thus, the inlet can be automatically opened to allow hydraulic oil to enter when the filter assembly is installed, and the inlet can be automatically closed to prevent hydraulic oil from entering when the filter assembly is disassembled for maintenance. This automatically controls the entry and sealing of hydraulic oil during installation and disassembly, which helps to simplify operation, improve efficiency, and avoid hydraulic oil leakage and pollution during disassembly, maintenance and cleaning.

[0014] 2. In this utility model, the two symmetrical filter chambers and filter components can filter synchronously, thereby improving filtration efficiency; or they can filter asynchronously and alternately, so that they can continue to work during the cleaning and maintenance of the filter components, which facilitates the continuity of construction and avoids the risk of project delays or equipment jams caused by downtime. Furthermore, the switching between alternating and synchronous filtration modes, combined with the step-by-step filtration method, can flexibly adapt to the pollution load and improve filtration efficiency. It has the advantages of balancing filtration efficiency and construction continuity, and redundancy to ensure system reliability. In addition, step-by-step filtration can also prevent large particles of impurities from directly impacting the small-pore fine filter element, thus extending its service life. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a frontal cross-sectional view of the synchronous filtration structure of the two sets of filter components of this utility model. Figure 2 This is a front cross-sectional view of the alternating filtration structure of the two sets of filter components of this utility model. Figure 3 This is a schematic diagram of the structure with an opening on the outer shell of this utility model.

[0017] In the diagram: 1. Oil tank; 2. Base; 21. T-shaped structural plate; 22. Buffer chamber; 23. Filter chamber; 24. Oil inlet; 25. Oil outlet; 3. Valve body assembly; 31. Damping rod; 32. Base plate; 33. Connecting rod; 34. Sealing body; 4. Filter assembly; 41. Outer shell; 411. Opening; 42. Outer filter body; 43. Mounting ring; 44. Base ring; 45. Inner filter body; 46. Bottom filter body. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Therefore, the following detailed description of the embodiments of this utility model is not intended to limit the scope of the claimed utility model, but merely represents some embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and "back side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this utility model is conventionally placed during use. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0021] It should also be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] In response to the problem that existing shield tunneling machine hydraulic oil filtration systems struggle to balance filtration efficiency with construction continuity, such as... Figures 1 to 3As shown in the figure, this embodiment of the present disclosure provides a multi-stage filtration device for hydraulic oil of a tunnel boring machine, including an oil tank 1 and a filtration structure. The oil tank 1 is externally connected to the filtration structure on its side. The filtration structure includes a base 2, a valve body assembly 3, and a filtration assembly 4. A T-shaped structural plate 21 is fixedly installed in the base 2 to separate and form a buffer chamber 22 located at the top and a symmetrically located filtration chamber 23 located at the bottom. The T-shaped structural plate 21 has an inlet on each of the two filtration chambers 23. The valve body assembly 3 is installed at the inlet. The filtration assembly 4 is installed in the filtration chamber 23. The valve body assembly is lifted or closed when the filtration assembly 4 is removed or installed.

[0023] The oil tank 1 is an existing partitioned sealed oil tank 1. The upper and lower sides of the base 2 are respectively provided with an oil inlet 24 and an oil outlet 25. The partitioned sealed oil tank 1 of the tunnel boring machine is connected to the oil inlet 24 and the oil outlet 25 through oil pipes, thus forming a system where hydraulic oil enters the base 2 from the oil tank 1 and then flows back to the oil tank 1. This use of the oil tank 1 to form a series circuit with other components containing hydraulic oil is a mature existing technology and will not be elaborated further here. Furthermore, an existing flow control valve can be installed at both the oil inlet 24 and the oil outlet 25 to control the flow and velocity of the hydraulic oil.

[0024] like Figure 1 and 2 As shown, it should also be noted that the two filter chambers 23 on the lower side of the substrate 2 are respectively provided with oil outlets 25 and are respectively connected to the oil tank 1.

[0025] During the filtration of the hydraulic oil in the tunnel boring machine (TBM), the hydraulic oil enters the oil tank 1 and then flows through the oil pipe to the oil inlet 24 at the top of the base 2. From there, it enters the buffer chamber 22 and then passes through the inlet to the corresponding filter chamber 23, where it is filtered by the filter assembly 4. It should be noted that the two symmetrical filter chambers 23 and the filter assembly 4 can filter simultaneously to improve filtration efficiency; or they can filter asynchronously and alternately, ensuring continued operation even during cleaning and maintenance of the filter assembly 4. This facilitates construction continuity and avoids increased risks of project delays or equipment malfunctions due to downtime. Furthermore, the switching between alternating and synchronous filtration modes can flexibly adapt to the pollution load and improve filtration efficiency. For example, when the hydraulic oil is lightly contaminated, switching to a single-group filter reduces the filtration intensity, thereby reducing oil flow resistance, improving the response speed of the hydraulic system, and alternating cleaning and maintenance reduces downtime and enhances construction continuity, meeting the needs of rapid tunneling by tunnel boring machines. When the contamination is severe, switching to dual-group synchronous filtration improves filtration efficiency and, in conjunction with multi-stage interception of impurities, ensures oil cleanliness and prevents contaminants from entering core components.

[0026] like Figure 1 and 2As shown, the valve body assembly 3 includes a damping rod 31, a base plate 32, a connecting rod 33, and a sealing body 34. The damping rod 31 is fixedly installed at the bottom of the inlet of the T-shaped structural plate 21, and the base plate 32 is fixedly installed at the other end of the damping rod 31. The connecting rod 33 is fixedly installed at the upper middle of the base plate 32, and the sealing body 34 is fixedly installed at the other end of the connecting rod 33.

[0027] When filtering the hydraulic oil of the tunnel boring machine, when the valve body assembly 3 closes the inlet, the damping rod 31 pushes up the base plate 32, causing the base plate 32 to move the connecting rod 33 and the sealing body downwards, thus blocking the inlet and preventing hydraulic oil from entering. When the valve body assembly 3 opens the inlet, the filter assembly 4 pushes up the base plate 32 and the damping rod 31, causing the connecting rod 33 and the sealing body 34 to move upwards and open the inlet to allow hydraulic oil to enter. The hydraulic oil then enters the corresponding filter chamber 23 from the inlet and is filtered by the filter assembly 4.

[0028] It should be noted that the damping rod 31 can adopt any existing rod-shaped structure with elastic support, such as existing spring telescopic rods, gas springs / pneumatic rods, or cylindrical helical compression spring telescopic rods; the sealing body can adopt any existing structure capable of sealing, such as existing plugs or piston seals; the sealing body 34 can be surrounded by fixed fluororubber for sealing, thereby enhancing the sealing performance and adapting to the working medium and ambient temperature of the shield machine hydraulic system. This is a mature existing technology and will not be elaborated further here.

[0029] like Figures 1 to 3 As shown, the filter assembly 4 includes a housing 41, an outer filter body 42, a mounting ring 43, and a base ring 44. The housing 41 has a cylindrical structure and multiple openings 411 are provided on the circumferential surface of the housing 41. The outer filter body 42 is fixedly installed in the openings 411. The mounting ring 43 is fixedly installed on the outer circumferential surface of the bottom of the housing 41. The filter cavity 23 protrudes inward and is fixedly fitted with an integrated base ring 44. After the base ring 44 and the mounting ring 43 are pressed together, the top end face of the housing 41 abuts against the bottom plate 32 and squeezes the damping rod 31.

[0030] When installing the filter assembly 4, the mounting ring 43 is fixedly installed on the base ring 44, so that the top of the outer shell 41 contacts the bottom plate 32 and lifts the bottom plate 32. After the outer shell 41 is fixed, the bottom plate 32 is pressed up and the damping rod 31 is squeezed, thereby driving the connecting rod 33 and the sealing body 34 to move upward and open the inlet.

[0031] When disassembling the filter assembly 4, the mounting ring 43 is removed from the surface of the base ring 44 and separated, thereby separating the top of the outer shell 41 from the bottom plate 32. This allows the damping rod 31 to lift the bottom plate 32, the connecting rod 33, and the sealing body, thereby enabling the sealing body to block the inlet and prevent hydraulic oil from entering the filter chamber 23.

[0032] After the hydraulic oil passes through the inlet and enters the filter chamber 23, it passes through the opening 411 on the housing and the filter screen for filtration. After filtration, it flows out through the opening 411 at the bottom of the housing and enters the bottom of the base 2, where it is discharged from the oil outlet 25 and flows back to the oil tank 1.

[0033] When the filter assembly 4 is installed, it lifts the enclosure to allow hydraulic oil to flow in. When it is disassembled, the enclosure blocks the inlet to prevent hydraulic oil from entering. This automatically blocks the hydraulic oil from entering when the filter assembly 4 is disassembled and cleaned, ensuring quick disassembly and improving efficiency while avoiding hydraulic oil leakage and pollution during disassembly, maintenance and cleaning.

[0034] It should be noted that the switching between alternating filtration and synchronous filtration modes can be achieved by personnel disassembling and assembling the filter components 4. That is, alternating filtration can be performed by alternately installing or removing a single filter component 4, while synchronous filtration can be performed by installing two filter components 4.

[0035] It should be noted that the fixing between the base ring 44 and the mounting ring 43 can be achieved using any existing detachable fixing method, such as the existing bolt fixing method used in this embodiment.

[0036] like Figure 1 and 2 As shown, an inner filter 45 is fixedly installed inside the outer casing 41, and the inner diameter of the mounting ring 43 is smaller than the inner diameter of the inner filter 45. The inner filter 45 fixedly installed inside the outer casing 41 can work with the outer filter 42 to achieve multi-stage filtration, thereby improving filtration efficiency and filtration accuracy, ensuring that the hydraulic oil used by the tunnel boring machine is free of impurities, and better adapting to the complex requirements of high pressure, continuous operation, and multiple pollutants.

[0037] like Figure 1 and 2 As shown, the sealing body 34 and the inlet have a truncated cone-shaped structure that fits together.

[0038] The frustum-shaped structure of the sealing body 34 and the inlet has a self-guiding function, allowing the sealing body to automatically slide into the fitting position along the conical surface with small centering error; on the other hand, it can also achieve high-pressure self-tightening sealing, which helps to enhance the sealing performance and prevent hydraulic oil leakage.

[0039] It should be noted that the cone angle of the frustum-shaped structure of the sealing body 34 and the inlet is 3°-15°.

[0040] like Figure 1 and 2As shown, a bottom filter body 46 is fixedly installed on the inner circumferential surface of the mounting ring 43. The bottom filter body 46 can cooperate with the outer filter body 42 and the inner filter body 45 to further achieve multi-stage filtration, thereby avoiding large particles from directly impacting the small-pore-diameter fine filter element, extending its service life, and further improving filtration efficiency and filtration accuracy. This further ensures that the hydraulic oil used by the tunnel boring machine is free of impurities and better meets the complex requirements of high pressure, continuous operation, and multiple pollutants.

[0041] The pore sizes of the inner filter 45, outer filter 42, and bottom filter 46 decrease sequentially. This sequentially decreasing pore size allows for staged filtration of the hydraulic oil, achieving graded interception filtration that is less prone to clogging, provides stable flow, and ensures deep filtration. This is beneficial for meeting the complex demands of high pressure, continuous operation, and multiple contaminants.

[0042] For example, in this embodiment of the present disclosure, the pore size of the outer filter body 42 is 80-120μm, which facilitates the interception of large rock fragments and metal abrasive particles; the pore size of the inner filter body 45 is 30-50μm, which facilitates the interception of medium-sized impurities during the transitional filtration stage; and the pore size of the bottom filter body 46 is 10-20μm, which facilitates the interception of fine impurities.

[0043] It should be noted that the inner filter 45, outer filter 42 and bottom filter 46 can adopt any existing structure or equipment capable of filtering hydraulic oil. In this embodiment of the disclosure, an existing filter screen is used to filter the hydraulic oil.

[0044] It should also be noted that, such as Figure 1 and 2 As shown, the bottom of the base 2 can be configured as two detachable and fixed plate-like structures corresponding to the filter chamber 23, thereby allowing the filter assembly 4 to be disassembled and reassembled by removing the bottom plate 32. For example, the bottom plate-like structure of the base is made of 304 stainless steel and is fixed to the base body by eight M12×30 bolts, with the bolts evenly distributed along the edge of the plate. The contact surface between the plate-like structure and the base is also equipped with a sealing ring to prevent hydraulic oil leakage. The parameters are based on the conventional design requirements of hydraulic equipment housings.

[0045] The process of filtering the hydraulic oil in a tunnel boring machine is as follows: After the hydraulic oil of the tunnel boring machine enters the oil tank 1, it enters the oil inlet 24 at the top of the base 2 through the oil pipe, and then enters the buffer chamber 22 through the oil inlet 24. At this time, at least one of the two filter chambers 23 located at the bottom of the base 2 is equipped with a filter assembly 4, thereby fixing the mounting ring 43 on the base ring 44, so that the top of the outer shell 41 contacts the bottom plate 32 and lifts the bottom plate 32. After the outer shell 41 is fixed, it presses the bottom plate 32 and squeezes the damping rod 31, thereby driving the connecting rod 33 and the sealing body 34 to move upward and open the inlet, so that the hydraulic oil can pass through the inlet and enter the corresponding filter chamber 23.

[0046] After the hydraulic oil enters the corresponding filter chamber 23, it passes through the outer filter screen, inner filter screen and bottom filter screen on the outer shell in sequence for filtration. This enables graded interception filtration that is not easy to clog, with stable flow and deep filtration, which is conducive to adapting to the complex needs of high pressure, continuous operation and multiple pollutants.

[0047] When maintenance and cleaning of one of the filter components 4 are required, the mounting ring 43 in one of the filter components 4 is removed from the surface of the base ring 44 and separated, thereby separating the top of the outer shell 41 from the bottom plate 32, thereby allowing the damping rod 31 to lift the bottom plate 32, the connecting rod 33 and the enclosure, and thus allowing the frustum-shaped enclosure to block the inlet and prevent hydraulic oil from entering the filter chamber 23.

[0048] The two symmetrical filter chambers 23 and filter components 4 can be configured for synchronous filtration to improve efficiency, or asynchronous alternating filtration, ensuring operation even during maintenance of one of them, which helps maintain construction continuity. Furthermore, the switching between alternating and synchronous filtration modes can flexibly adapt to contamination loads and improve filtration efficiency. For example, when the hydraulic oil is lightly contaminated, switching to a single-set filter reduces filtration intensity, thereby reducing oil flow resistance, improving the hydraulic system's response speed, and alternating cleaning and maintenance reduces downtime, enhancing construction continuity and meeting the needs of rapid tunneling by the tunnel boring machine. When contamination worsens, switching to dual-set synchronous filtration improves filtration efficiency, and multiple stages of impurity interception ensure oil cleanliness, preventing contaminants from entering core components.

[0049] Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A multi-stage hydraulic oil filtration device for a tunnel boring machine, comprising an oil tank (1) and a filter structure, wherein the filter structure is externally connected to the side of the oil tank (1), characterized in that: The filter structure includes a base (2), a valve assembly (3), and a filter assembly (4). A T-shaped structural plate (21) is fixedly installed in the base (2) to separate and form a buffer chamber (22) located at the top and a filter chamber (23) located at the bottom and symmetrically arranged on the left and right. The T-shaped structural plate (21) has an inlet on each of the two filter chambers (23). The valve assembly (3) is installed at the inlet. The filter assembly (4) is installed in the filter chamber (23). The removal and installation of the filter assembly (4) can lift or close the valve assembly (3).

2. The multi-stage filtration device for hydraulic oil of a tunnel boring machine according to claim 1, characterized in that: The valve body assembly (3) includes a damping rod (31), a base plate (32), a connecting rod (33), and a sealing body (34). The damping rod (31) is fixedly installed at the bottom of the inlet of the T-shaped structural plate (21). The base plate (32) is fixedly installed at the other end of the damping rod (31). The connecting rod (33) is fixedly installed at the top middle of the base plate (32). The sealing body (34) is fixedly installed at the other end of the connecting rod (33).

3. The shield machine hydraulic oil multi-filtration device according to claim 2, characterized in that: The filter assembly (4) includes an outer shell (41), an outer filter (42), a mounting ring (43), and a base ring (44). The outer shell (41) has a cylindrical structure and multiple openings (411) are provided on the circumferential surface of the outer shell (41). The outer filter (42) is fixedly installed in the openings (411). The mounting ring (43) is fixedly installed on the outer circumferential surface of the bottom of the outer shell (41). The filter cavity (23) protrudes inward and is fixedly fitted with an integrated base ring (44). After the base ring (44) and the mounting ring (43) are pressed together, the top end face of the outer shell (41) abuts against the bottom plate (32) and squeezes the damping rod (31).

4. The multi-stage filtration device for hydraulic oil in a tunnel boring machine according to claim 3, characterized in that: An inner filter (45) is fixedly installed inside the outer shell (41), and the inner diameter of the mounting ring (43) is smaller than the inner diameter of the inner filter (45).

5. The multi-stage filtration device for hydraulic oil of a tunnel boring machine according to claim 4, characterized in that: The sealing body (34) and the inlet are in a truncated cone shape that fits together.

6. The multi-stage filtration device for hydraulic oil of a tunnel boring machine according to claim 5, characterized in that: The bottom filter body (46) is fixedly installed on the inner circumferential surface of the mounting ring (43).

7. The multi-stage filtration device for hydraulic oil of a tunnel boring machine according to claim 6, characterized in that: The pore sizes of the inner filter (45), outer filter (42), and bottom filter (46) decrease sequentially.

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