Filter device for hydraulic system

Abstract

A filter device for a hydraulic system comprises: a filter cartridge, a collecting tank formed at the bottom of the filter cartridge, and a guide groove extending downward arranged on one side of the collecting tank; the filter element is arranged in the filter cartridge and is connected with the top of the filter cartridge through a first spring, and the upper part of the side wall of the filter element is in sealing fit with the inner wall of the filter cartridge; the rotating stand is rotationally arranged at the bottom of the filter cartridge; the cleaning scraper is fixed on the upper surface of the rotating stand and is in contact with the outer wall of the filter element; the collecting scraping plate is fixed on the lower surface of the rotating stand and is matched with the collecting groove; the rotating stand can periodically impact the bottom of the filter element upwards in the rotating process so as to drive the filter element to generate reciprocating vibration in the axial direction; the chip removal seat is arranged at the bottom of the side wall of the filter cartridge and communicated with the guide groove. The scraping plate capable of rotating under the pushing of oil pressure is arranged on the outer side of the filter element, so that pollutants such as scrap iron attached to the surface of the filter element can be effectively scraped; meanwhile, the scraper rotates to drive the filter element to generate reciprocating vibration, so that the filter element is further cleaned, and frequent replacement of the filter element is avoided.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic system technology, specifically referring to a filter device for hydraulic systems. Background Technology

[0002] The reliability and lifespan of a hydraulic system directly depend on the cleanliness of the hydraulic fluid. After commissioning or overhauling new equipment, hard contaminants such as machining chips, welding scale, and rust that are inherent in the system will be released in a concentrated manner, posing a severe challenge to the filters.

[0003] Existing filters primarily employ passive interception methods and generally lack effective self-cleaning capabilities. This leads to two major drawbacks: First, frequent filter element replacement. During periods of high pollution (such as the hot and humid rainy season), filter elements are highly susceptible to irreversible deep clogging. Maintenance personnel must repeatedly replace them with high intensity, increasing spare parts and labor costs, and causing equipment downtime due to frequent maintenance, affecting production continuity. Second, clogging induces abnormal pressure and safety risks. A clogged filter element drastically reduces the flow cross-section, creating localized high pressure upstream. If this pressure exceeds the system's pressure limit, it may cause the filter housing or pipe joints to rupture, leading to media leakage. In severe cases, the high pressure differential can puncture the filter element, causing accumulated contaminants to rush into the system instantly, causing secondary damage to precision components such as pumps and valves, posing a serious safety hazard. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides a filter device for hydraulic systems, which at least partially solves the above problems.

[0005] The technical solution adopted by this invention is as follows: This invention proposes a filter device for a hydraulic system, comprising: A filter cartridge is connected to a hydraulic system. The bottom of the filter cartridge has an annular collection groove, and one side of the collection groove has a downwardly extending guide groove. A filter element is disposed inside the filter cartridge, and its top end is connected to the top of the filter cartridge by a first spring, so that the filter element can make elastic displacement along the axial direction. The upper part of the side wall of the filter element and the inner wall of the filter cartridge form a sealing fit. The rotary cleaning assembly includes a rotating frame rotatably mounted at the bottom of the filter cartridge, a cleaning scraper fixed to the upper surface of the rotating frame and in contact with the outer wall of the filter element, and a collection scraper fixed to the lower surface of the rotating frame and cooperating with the collection groove. During rotation, the rotating frame can periodically strike the bottom of the filter element upwards to drive the filter element to reciprocate along the axial direction. A chip discharge seat is located at the bottom of the side wall of the filter cartridge and communicates with the guide groove, used to discharge the pollutants collected in the guide groove from the filter cartridge.

[0006] Furthermore, the bottom of the filter element is provided with a groove, and a first protrusion is provided in the groove. The rotating frame is located below the filter element, and a second protrusion is correspondingly provided on the rotating frame. The distribution radius of the second protrusion is adapted to the first protrusion. When the rotating frame rotates, the second protrusion can periodically contact and lift the first protrusion.

[0007] Furthermore, the upper end of the filter cartridge is sealed with a cover, which is provided with an oil inlet and an oil outlet. A filter chamber is formed inside the filter cartridge, and the filter chamber is connected to the oil inlet and the oil outlet through the filtering effect of the filter element.

[0008] Furthermore, the upper end of the filter chamber is provided with a vibration chamber, which is connected to the oil outlet and the internal flow channel of the filter element. The upper part of the side wall of the filter element and the inner wall of the vibration chamber are in a sealed sliding fit, and the first spring is housed in the vibration chamber.

[0009] Furthermore, a central column is provided at the center of the bottom wall of the filter chamber. The upper section of the central column has a polygonal cross-section, and the lower section has a circular cross-section. The filter element is slidably sleeved on the upper section of the central column and can move axially, and is non-rotatable in conjunction with the polygonal cross-section. The rotating frame is rotatably sleeved on the lower section of the central column through a bearing structure.

[0010] Furthermore, a chip removal cavity is formed inside the chip removal seat, which is connected to the guide groove; a sealing plate for opening and closing the chip removal cavity is rotatably connected to the chip removal cavity via a rotating rod. The sealing plate is controlled by a pressure drive component to achieve automatic opening. A torsion spring is provided between the rotating rod and the chip removal seat, which provides a reset torque to keep the sealing plate closed.

[0011] Furthermore, the pressure drive assembly includes a pressure rod and a spring. The pressure rod extends through the chip removal seat into the chip removal cavity. A second spring connects the top end of the pressure rod protruding outside the chip removal seat to the chip removal seat. When the rotational torque generated by the pressure on the sealing plate on the rotating rod is greater than the closing torque applied to the sealing plate by the second spring through the pressure rod, the sealing plate can rotate around the rotating rod, thereby opening the chip removal cavity.

[0012] Furthermore, the bottom end of the pressure rod is provided with a trigger plug plate, which has a limiting groove; the end of the sealing plate is provided with a limiting block, and the cooperation between the limiting block and the limiting groove forms a linkage mechanism. When the trigger plug plate is pressed and moved, the sealing plate is driven to perform an opening or closing action by changing the cooperation state between the limiting block and the limiting groove; the shape of the trigger plug plate is adapted to the chip discharge cavity so that when the sealing plate is in a horizontal state, it together with the sealing plate forms a seal for the chip discharge cavity.

[0013] Furthermore, the end of the sealing plate away from the trigger blocking plate is constructed as an arc-shaped structure, and the corresponding side wall shape of the chip discharge cavity is adapted to the arc-shaped structure; when the sealing plate is in the open state, the two ends of its arc-shaped structure respectively seal and abut against the upper and lower walls of the chip discharge cavity, thereby blocking the feeding passage of the chip discharge cavity.

[0014] The beneficial effects achieved by this invention are as follows: By setting a scraper that can rotate under hydraulic pressure on the outside of the filter element, contaminants such as iron filings attached to the surface of the filter element can be effectively scraped off; at the same time, when the scraper rotates, it drives the filter element to reciprocate and vibrate, forming a synergistic cleaning effect of "scraping and shaking off", avoiding frequent replacement of the filter element; after the scraped contaminants are collected in the chip discharge seat, the contaminant density is converted into a pressure signal. When the pressure reaches the set value, the chip discharge seat can automatically open and discharge the contaminants in a concentrated manner, realizing the self-cleaning function of the filter. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a filter device for a hydraulic system according to an embodiment of the present invention; Figure 2 for Figure 1 A sectional view; Figure 3 A cross-sectional view of the filter cartridge and the cap; Figure 4 A diagram showing the positional relationship between the filter element, the first spring, and the cleaning scraper; Figure 5 This is a schematic diagram of the filter element structure; Figure 6 A schematic diagram of the rotating frame, the collection scraper, and the cleaning scraper; Figure 7 This is a cross-sectional view of the filter cartridge; Figure 8 This is a diagram showing the state of the sealing plate during chip removal; Figure 9 This is a diagram showing the positional relationship between the limit block and the limit groove.

[0016] The components are as follows: 1. Filter cartridge; 2. Cover; 3. Chip removal seat; 4. Filter element; 5. First spring; 6. Cleaning scraper; 7. Sealing plate; 8. Pressure rod; 9. Second spring; 10. Rotating rod; 11. Torsion spring; 12. Oil inlet; 13. Oil outlet; 14. Filter chamber; 15. Vibration chamber; 16. Central column; 17. Collection groove; 18. Guide groove; 19. Chip removal chamber; 20. Groove; 21. First protrusion; 22. Rotating frame; 23. Second protrusion; 24. Collection scraper; 25. Limiting block; 26. Triggering block; 27. Limiting groove.

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 invention.

[0020] like Figures 1-3 As shown in the embodiment of the present invention, a filter device for a hydraulic system includes a filter cartridge 1, a filter element 4, a rotary cleaning assembly, and a chip removal seat 3. The filter cartridge 1 is connected to the hydraulic system. The filter element 4 is disposed inside the filter cartridge 1. Hydraulic oil enters the filter cartridge 1 and is filtered by the filter element 4, separating and intercepting impurities in the oil. The rotary cleaning assembly is rotatably disposed inside the filter cartridge 1 and cooperates with the outer wall of the filter element 4 to scrape off impurities from the surface of the filter element 4. An annular collection groove 17 is formed at the bottom of the filter cartridge 1. A downwardly extending guide groove 18 is provided on one side of the collection groove 17. The scraped impurities fall into the collection groove 17 and are pushed into the guide groove 18 during the reciprocating cycle. Specifically, such as Figure 4 and Figure 6 As shown, the rotary cleaning assembly includes a rotating frame 22 rotatably mounted at the bottom of the filter cartridge 1, a cleaning scraper 6 fixed to the upper surface of the rotating frame 22 and in contact with the outer wall of the filter element 4, and a collection scraper 24 fixed to the lower surface of the rotating frame 22 and cooperating with the collection groove 17. During rotation, the rotating frame 22 can periodically strike the bottom of the filter element 4 upwards to drive the filter element 4 to reciprocate along the axial direction. In order to make the filter element 4 reciprocate, the top of the filter element 4 is connected to the top of the filter cartridge 1 through a first spring 5, so that the filter element 4 can make elastic displacement along the axial direction. The upper part of the side wall of the filter element 4 and the inner wall of the filter cartridge 1 form a sealing fit to prevent unfiltered oil from passing through the gap between the filter element 4 and the inner wall of the filter cartridge 1 during reciprocating vibration.

[0021] During operation, hydraulic oil enters the filter cartridge 1, forming a fluid with a certain impact force. The fluid impacts the cleaning scraper 6, which, under pressure, drives the rotating frame 22 to rotate, and simultaneously drives the collecting scraper 24 below to rotate. The rotating cleaning scraper 6 scrapes away impurities from the surface of the filter element 4. The impurities fall into the collecting groove 17 below, and are then scraped by the collecting scraper 24 to accumulate in the guide groove 18. While the rotating frame 22 rotates, it periodically pushes the filter element 4 upward, causing the filter element 4 to vibrate back and forth, so as to shake off the small impurities embedded in the filter screen, avoid clogging the filter element 4, and extend the service life of the filter element 4. The first spring 5 plays a protective, buffering, and resetting role for the filter element 4.

[0022] After impurities are collected in the guide groove 18, the chip discharge seat 3, which is located at the bottom of the side wall of the filter cartridge 1 and communicates with the guide groove 18, will convert the density of impurities into a pressure signal. When the pressure reaches the set value, the chip discharge seat 3 can automatically open for centralized discharge, realize periodic discharge, ensure the normal working cycle of the filter element 4, and avoid the adverse effects caused by the blockage of the filter element 4.

[0023] In some embodiments, such as Figure 5 and Figure 6 As shown, the bottom of the filter element 4 is provided with a groove 20, and a first protrusion 21 is provided in the groove 20. The rotating frame 22 is located below the filter element 4, and a second protrusion 23 is correspondingly provided on the rotating frame 22. The distribution radius of the second protrusion 23 is adapted to the first protrusion 21. When the rotating frame 22 rotates, the second protrusion 23 can periodically contact the first protrusion 21, and at the same time, the first protrusion 21 is lifted upward. The first protrusion 21 drives the filter element 4 to move upward against the resistance of the first spring 5. When the first protrusion 21 separates from the second protrusion 23, the filter element 4 falls back downward under the action of the first spring 5, so that the filter element 4 slides back and forth periodically in the vertical direction, forming vibration, thereby peeling off impurities from the surface of the filter element 4 and the mesh of the filter element 4, and improving the service life of the filter element 4.

[0024] In some embodiments, such as Figure 2 As shown, a cover 2 is sealed to the upper end of the filter cartridge 1. The cover 2 is provided with an oil inlet hole 12 and an oil outlet hole 13. A filter chamber 14 is formed inside the filter cartridge 1. The filter chamber 14 is connected to the oil inlet hole 12 and the oil outlet hole 13 through the filtering effect of the filter element 4. A vibration chamber 15 is provided at the upper end of the filter chamber 14. The vibration chamber 15 is connected to the oil outlet hole 13 and the internal flow channel of the filter element 4. The upper part of the side wall of the filter element 4 and the inner wall of the vibration chamber 15 are sealed and slidingly fitted. The first spring 5 is housed in the vibration chamber 15. During the vibration of the filter element 4, the filter element 4 will only vibrate slightly within the stroke range of the vibration chamber 15 in the height direction, so that the oil inlet hole 12 and the oil outlet hole 13 on both sides of the filter element 4 are always isolated. The original oil cannot pass through the filter element 4 and directly enter the oil outlet hole 13, avoiding the problem of unfiltered oil due to vibration.

[0025] In some embodiments, a central column 16 is provided at the center of the bottom wall of the filter chamber 14. The upper section of the central column 16 has a polygonal cross-section and the lower section has a circular cross-section. The filter element 4 is slidably sleeved on the upper section of the central column 16 and can move axially. It is matched with the polygonal cross-section and cannot rotate, so as to generate up-and-down vibration. The rotating frame 22 is rotatably sleeved on the lower section of the central column 16 through a bearing structure. The bearing structure can significantly reduce the friction force on the rotating frame 22 when it rotates, which is more conducive to its rotation under the impact of hydraulic oil.

[0026] In some embodiments, such as Figure 3 and Figure 7 As shown, a chip removal chamber 19 is formed inside the chip removal seat 3, which is connected to the guide groove 18. A sealing plate 7 for opening and closing the chip removal chamber 19 is rotatably connected to the chip removal chamber 19 via a rotating rod 10. The sealing plate 7 is controlled by a pressure drive component to achieve automatic opening. A torsion spring 11 is provided between the rotating rod 10 and the chip removal seat 3. The torsion spring 11 provides a reset torque to keep the sealing plate 7 closed. When impurities in the guide groove 18 enter the chip removal chamber 19, they will apply a certain pressure to the chip removal chamber 19. As the impurities and contaminants continue to enter, these impurities are gradually squeezed, causing the pressure in the chip removal chamber 19 to gradually increase. When the pressure reaches the set value of the pressure drive component, the sealing plate 7 is driven to open, so that the contaminants in the chip removal chamber 19 fall off instantly (if necessary, a collection device can be set below the filter cartridge 1 to avoid contamination). When the contaminants are completely removed, the pressure in the chip removal chamber 19 is instantly restored, the pressure drive component returns to its initial state, and the sealing plate 7 is reset to a horizontal state under the action of the torsion spring 11 to continue the next round of operation.

[0027] In some embodiments, such as Figure 8 and Figure 9 As shown, the pressure drive assembly includes a pressure rod 8 and a spring. The pressure rod 8 extends through the chip removal seat 3 into the chip removal cavity 19. The top end of the pressure rod 8 protruding from the chip removal seat 3 is connected to the chip removal seat 3 by a second spring 9. The pressure rod 8 is used to limit the rotation angle of the sealing plate 7. When the rotational torque generated by the pressure on the sealing plate 7 on the rotating rod 10 is greater than the closing torque applied to the sealing plate 7 by the second spring 9 through the pressure rod 8, this pressure drives the pressure rod 8 to overcome the resistance of the second spring 9 and lift it upward, so that the pressure rod 8 no longer restricts the sealing plate 7. The impurities and contaminants on the sealing plate 7 are driven to rotate around the rotating rod 10 under the action of gravity, so that the impurities and contaminants fall out of the chip removal cavity 19, thereby completing the chip removal operation.

[0028] In some embodiments, the bottom end of the pressure rod 8 is provided with a trigger stop plate 26, on which a limiting groove 27 is formed; the end of the sealing plate 7 is provided with a limiting block 25. When the limiting block 25 is slidably fitted into the limiting groove 27, the limiting block 25 and the limiting groove 27 are slidably connected, and the angle between the limiting block 25 and the limiting groove 27 is fixed, so that the limiting block 25 cannot rotate, thereby forcibly driving the sealing plate 7 to maintain a horizontal closed state; when the pressure on the sealing plate 7 increases and overcomes the second spring 9 When the pre-tightening force is applied, the pressure rod 8 drives the trigger plate 26 to move upward, causing the limiting block 25 to disengage from the limiting groove 27. The limiting block 25 is no longer restricted by the side wall of the limiting groove 27, and the limiting block 25 can rotate and open around the rotating rod 10 with the sealing plate 7 to achieve chip removal. At the same time, the shape of the trigger plate 26 is adapted to the chip removal cavity 19. When the sealing plate 7 is in a horizontal state, the trigger plate 26 and the sealing plate 7 jointly seal the side wall and bottom wall of the chip removal cavity 19, so that the chip removal cavity 19 remains sealed.

[0029] In some embodiments, the end of the sealing plate 7 away from the trigger blocking plate 26 is constructed as an arc-shaped structure, and the corresponding side wall shape of the chip discharge cavity 19 is adapted to the arc-shaped structure. When the sealing plate 7 is rotated open, the arc-shaped structure can maintain a sealed fit with the side wall of the chip discharge cavity 19. When the sealing plate 7 is opened, the two ends of its arc-shaped structure respectively seal against the upper and lower walls of the chip discharge cavity 19, and the feed passage of the chip discharge cavity 19 is blocked, so as to avoid the hydraulic oil in the filter cartridge 1 from interfering with the chip discharge operation of the chip discharge cavity 19, causing a large amount of oil to be sprayed out instantly and polluting the surrounding environment.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A filter device for a hydraulic system, characterized in that, include: A filter cartridge (1) is connected to a hydraulic system. A ring-shaped collection groove (17) is formed at the bottom of the filter cartridge (1), and a downwardly extending guide groove (18) is provided on one side of the collection groove (17). The filter element (4) is disposed inside the filter cylinder (1), and its top end is connected to the top of the filter cylinder (1) by a first spring (5), so that the filter element (4) can make elastic displacement along the axial direction. The upper part of the side wall of the filter element (4) and the inner wall of the filter cylinder (1) form a sealing fit. The rotating cleaning assembly includes a rotating frame (22) rotatably disposed at the bottom of the filter cartridge (1), a cleaning scraper (6) fixed on the upper surface of the rotating frame (22) and in contact with the outer wall of the filter element (4), and a collection scraper (24) fixed on the lower surface of the rotating frame (22) and cooperating with the collection groove (17). The rotating frame (22) can periodically strike the bottom of the filter element (4) upward during rotation to drive the filter element (4) to reciprocate along the axial direction. The chip removal seat (3) is located at the bottom of the side wall of the filter cartridge (1) and communicates with the guide groove (18) to discharge the pollutants collected in the guide groove (18) from the filter cartridge (1).

2. The filter device for a hydraulic system according to claim 1, characterized in that: The bottom of the filter element (4) is provided with a groove (20), and a first protrusion (21) is provided in the groove (20). The rotating frame (22) is located below the filter element (4), and a second protrusion (23) is correspondingly provided on the rotating frame (22). The distribution radius of the second protrusion (23) is adapted to the first protrusion (21). When the rotating frame (22) rotates, the second protrusion (23) can periodically contact and lift the first protrusion (21).

3. The filter device for a hydraulic system according to claim 1, characterized in that: The filter cartridge (1) is sealed with a cover (2) at the upper end. The cover (2) is provided with an oil inlet (12) and an oil outlet (13). The filter cartridge (1) has a filter chamber (14) inside. The filter chamber (14) is connected to the oil inlet (12) and the oil outlet (13) through the filtering effect of the filter element (4).

4. The filter device for a hydraulic system according to claim 3, characterized in that: The upper end of the filter chamber (14) is provided with a vibration chamber (15). The vibration chamber (15) is connected to the oil outlet (13) and the internal flow channel of the filter element (4). The upper part of the side wall of the filter element (4) and the inner wall of the vibration chamber (15) are in a sealed sliding fit. The first spring (5) is housed in the vibration chamber (15).

5. The filter device for a hydraulic system according to claim 3, characterized in that: The filter chamber (14) has a central column (16) at the center of its bottom wall. The upper section of the central column (16) has a polygonal cross-section, and the lower section has a circular cross-section. The filter element (4) is slidably sleeved on the upper section of the central column (16) and can move axially. It is matched with the polygonal cross-section and cannot rotate. The rotating frame (22) is rotatably sleeved on the lower section of the central column (16) through a bearing structure.

6. The filter device for a hydraulic system according to claim 1, characterized in that: The chip removal seat (3) has a chip removal cavity (19) inside, which is connected to the guide groove (18). A sealing plate (7) for opening and closing the chip removal cavity (19) is rotatably connected to the chip removal cavity (19) via a rotating rod (10). The sealing plate (7) is controlled by a pressure drive component to achieve automatic opening. A torsion spring (11) is provided between the rotating rod (10) and the chip removal seat (3). The torsion spring (11) provides a reset torque to keep the sealing plate (7) closed.

7. The filter device for a hydraulic system according to claim 6, characterized in that: The pressure drive assembly includes a pressure rod (8) and a spring. The pressure rod (8) extends through the chip removal seat (3) into the chip removal cavity (19). The top of the pressure rod (8) protruding outside the chip removal seat (3) is connected to the chip removal seat (3) by a second spring (9). When the pressure on the sealing plate (7) generates a rotational torque on the rotating rod (10) that is greater than the closing torque applied to the sealing plate (7) by the second spring (9) through the pressure rod (8), the sealing plate (7) can rotate around the rotating rod (10) to open the chip removal cavity (19).

8. The filter device for a hydraulic system according to claim 7, characterized in that: The bottom end of the pressure rod (8) is provided with a trigger plug plate (26), and a limit groove (27) is provided on the trigger plug plate (26); the end of the sealing plate (7) is provided with a limit block (25), and the cooperation relationship between the limit block (25) and the limit groove (27) constitutes a linkage mechanism. When the trigger plug plate (26) is pressed and moved, the sealing plate (7) is driven to perform opening or closing actions by changing the cooperation state between the limit block (25) and the limit groove (27); the shape of the trigger plug plate (26) is adapted to the chip discharge cavity (19) so that when the sealing plate (7) is in a horizontal state, it together with the sealing plate (7) forms a seal for the chip discharge cavity (19).

9. The filter device for a hydraulic system according to claim 8, characterized in that: The end of the sealing plate (7) away from the trigger blocking plate (26) is constructed as an arc-shaped structure, and the corresponding side wall shape of the chip discharge cavity (19) is adapted to the arc-shaped structure. When the sealing plate (7) is in the open state, the two ends of its arc-shaped structure are respectively sealed and abutted against the upper and lower walls of the chip discharge cavity (19), thereby blocking the feeding passage of the chip discharge cavity (19).

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