A dustproof grinding device for carbon brush processing
By designing a dustproof grinding device for carbon brush processing, the angle and height of the grinding wheel can be adjusted using a main controller and motor system. Combined with cooling, dust reduction, and waste chip collection, the problems of poor consistency and low efficiency in traditional carbon brush manufacturing are solved, thereby improving production efficiency and product stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI HUDONG ELECTRIC CARBON CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional carbon brush manufacturing relies on manual operation, resulting in poor consistency, low production efficiency, and high costs. Furthermore, the grinding equipment can only perform grinding in a fixed direction, which cannot meet the needs of different angles.
A dustproof grinding device for carbon brush processing was designed. The main controller controls the drive motor and servo motor to achieve angle and height adjustment of the grinding wheel. It is equipped with a cooling and dust reduction system and a negative pressure fan to collect waste chips, thereby improving grinding efficiency and product stability.
It achieves automated and efficient grinding of carbon brushes, improves production consistency and efficiency, reduces production costs, and can adapt to grinding needs at different angles, while also having cooling and dust reduction functions.
Smart Images
Figure CN224334132U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of carbon brush grinding technology, and in particular to a dustproof grinding device for carbon brush processing. Background Technology
[0002] Carbon brushes, also known as electric brushes, are widely used in many electrical devices as sliding contact components. The main materials used in carbon brush production include graphite, resin-impregnated graphite, and metallic (including copper and silver) graphite. Carbon brushes are devices that transmit energy or signals between the stationary and rotating parts of electric motors, generators, or other rotating machinery. They are generally made of pure carbon with a coagulant, and are typically square in shape with a wire leading out from one side. They are held in place by a metal bracket, and a spring inside presses them firmly against the shaft. When the motor rotates, it transmits electrical energy to the coil through a commutator. Traditional brush manufacturing technology typically involves manual chamfering and grinding of the brushes. This results in inconsistent carbon brushes, affecting product quality and stability. Furthermore, the entire manufacturing process is manual, time-consuming, labor-intensive, inefficient, and costly. Additionally, the grinding device can only grind in a fixed direction, requiring the angle of components to be changed to achieve different angles, further reducing grinding efficiency. Therefore, we have redesigned a dustproof grinding device for carbon brush processing. Summary of the Invention
[0003] The purpose of this invention is to provide a dustproof grinding device for carbon brush processing.
[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a dustproof grinding device for carbon brush processing, comprising a carbon brush processing table, a processing machine frame fixedly installed on one side top of the carbon brush processing table, a main controller fixedly installed on the bottom of one side front of the processing machine frame, a sliding adjustment groove formed on the top surface of one side of the processing machine frame, a drive threaded rod movably installed inside the sliding adjustment groove, a sliding top plate movably installed on one side surface of the drive threaded rod, a drive motor fixedly installed on the outer wall of one side of the top of the processing machine frame, and a motor control device fixedly connected between the main controller and the drive motor. The sliding top plate has a servo motor fixedly installed on one bottom side. A lifting rod is telescopically connected to one bottom side of the servo motor. A connecting base is fixedly connected to one bottom side of the lifting rod. An angle adjustment motor is fixedly installed on the back side of one side of the connecting base. A rotating disk is rotatably connected to one front side of the connecting base. A connecting rod is fixedly connected to one side of the rotating disk. A mounting plate is fixedly installed on the top side of one side of the connecting rod. A grinding motor is fixedly installed on the back side of one side of the mounting plate. A rotating shaft is rotatably connected to one front side of the mounting plate. A grinding wheel is fixedly connected to the top side of one side of the rotating shaft.
[0005] Preferably, the drive motor and the drive threaded rod are connected by a drive connection, the drive motor and the main controller are connected by an electric control connection, the sliding top plate is located inside the sliding adjustment groove, the sliding top plate and the sliding adjustment groove are connected by a sliding connection, and the drive threaded rod passes through the interior of the sliding top plate, the drive threaded rod and the sliding top plate are connected by a threaded drive connection.
[0006] Preferably, the servo motor and the lifting rod are connected in a vertical drive telescopic connection, the angle adjustment motor and the rotating disk are connected in a rotation drive connection, and the grinding motor and the rotating shaft are connected in a rotation drive connection.
[0007] Preferably, a water pipe clamping plate is fixedly installed on one side surface of the connecting chassis, and a cooling and dust suppression water pipe is movably clamped inside the water pipe clamping plate. A water pipe control valve is provided on the top surface of one side of the cooling and dust suppression water pipe.
[0008] Preferably, a waste collection bucket is fixedly installed on the top surface of one side of the carbon brush processing table. The top surface of the waste collection bucket is connected to a processing tray. A filter plate is fixedly installed inside the processing tray. A collection hole is opened on the surface of the filter plate. A fixed plate is fixedly installed on one side of the processing tray. A sliding adjustment plate is fixedly connected to one side of the fixed plate. A sliding limit rail is fixedly installed on the inner wall of the sliding adjustment plate. A sliding base is slidably connected to one side of the sliding limit rail. A retainer is fixedly installed on the top surface of one side of the sliding base. A pressing threaded rod is movably connected to the top surface of the retainer. A rotating adjustment handle is fixedly connected to the top surface of one side of the pressing threaded rod. A connecting bearing is rotatably connected to the bottom end of one side of the pressing threaded rod. A pressing fixed plate is fixedly connected to the bottom end of the connecting bearing. A pressing claw plate is fixedly connected to the surface of the retainer near the pressing fixed plate.
[0009] Preferably, there are two fixed disks, which are symmetrically distributed on both sides of the processing table. The sliding base is located inside the sliding adjustment disk, and the sliding base and the sliding adjustment disk are slidably connected. The extrusion threaded rod passes through the top surface of the fixture, and the connection between the extrusion threaded rod and the fixture is a threaded connection. The extrusion fixed disk is located between the top of the fixture and the extrusion claw disk. The collection hole passes through the surface of the filter disk, and there are several collection holes, which are circumferentially distributed on the surface of the filter disk.
[0010] Preferably, a cleaning auxiliary door is provided on one side surface of the waste collection bin, a negative pressure air box is fixedly installed on one side of the waste collection bin, a negative pressure fan is installed inside the negative pressure air box, a negative pressure communication groove is opened on the front side of one side of the negative pressure air box, an external communication groove is opened on the side surface of the negative pressure air box, and a fan power box is fixedly installed on the back of the negative pressure air box.
[0011] Preferably, the negative pressure air box and the waste collection bucket are connected through the negative pressure connecting groove. The external connecting groove penetrates the interior of the negative pressure air box. There are several external connecting grooves, which are symmetrically distributed at equal intervals on both sides of the negative pressure air box. The connection between the fan power box and the negative pressure fan is a power control connection.
[0012] Compared with related technologies, the dustproof grinding device for carbon brush processing provided by this utility model has the following advantages:
[0013] This utility model provides a dustproof grinding device for carbon brush processing. A main controller directly controls the start-up of the drive motor, which in turn controls the drive threaded rod to move the sliding top plate for horizontal sliding adjustment. A servo motor at the bottom of the sliding top plate directly controls the extension and retraction of the lifting rod to adjust its height. An angle adjustment motor controls the rotation angle of the rotating disk, thereby achieving appropriate adjustment of the grinding wheel's operating angle. For carbon brush processing at different angles, the grinding motor drives the rotating shaft to rotate, thus using the grinding wheel to perform the grinding operation on the carbon brush. During the grinding process, a cooling and dust-reducing water pipe connected to a water body enables water spraying to cool and reduce dust on the grinding wheel.
[0014] This utility model provides a dustproof grinding device for carbon brush processing. The distance between the two retainers is adjusted by sliding the position of the sliding base on the sliding limit rail, according to the actual length of the carbon brush. The position of the extrusion threaded rod on the top surface of the retainer is adjusted by rotating the adjustment handle. The carbon brush is clamped and fixed by the extrusion fixing plate and the extrusion claw plate. Negative pressure control is achieved by a negative pressure fan inside the negative pressure air box on the side of the waste collection bin, directly absorbing the grinding waste into the interior of the waste collection bin. The collection hole can directly absorb the waste. The waste collection bin also collects waste liquid, which can then be centrally cleaned by opening the cleaning auxiliary chamber door. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 This is a three-dimensional structural diagram of the present invention;
[0017] Figure 2 This is a schematic diagram of the overall side top view of the device of this utility model;
[0018] Figure 3 This is a schematic diagram of the grinding equipment structure of this utility model;
[0019] Figure 4 This is a schematic diagram of the overall top view of the back of the device of this utility model;
[0020] Figure 5 This is a schematic diagram of the fixture structure of this utility model;
[0021] Figure 6 This is a schematic diagram of the negative pressure air box structure of this utility model.
[0022] The diagram shows the following components: 1. Carbon brush processing table; 2. Processing machine frame; 3. Main controller; 4. Sliding adjustment groove; 5. Drive threaded rod; 6. Sliding top plate; 7. Drive motor; 8. Motor control connection cable; 9. Servo motor; 10. Lifting rod; 11. Connecting chassis; 12. Angle adjustment motor; 13. Rotating disk; 14. Connecting rod; 15. Mounting plate; 16. Grinding motor; 17. Rotating shaft; 18. Grinding wheel; 19. Water pipe clamping plate; 20. Cooling and dust suppression water pipe; 21. Water pipe control valve. 22. Waste collection bin; 23. Processing table; 24. Fixed plate; 25. Sliding adjustment plate; 26. Sliding limit rail; 27. Sliding chassis; 28. Fixer; 29. Extrusion threaded rod; 30. Rotation adjustment handle; 31. Connecting bearing; 32. Extrusion fixed plate; 33. Extrusion claw plate; 34. Cleaning auxiliary door; 35. Negative pressure air box; 36. Negative pressure fan; 37. Negative pressure connecting groove; 38. External connecting groove; 39. Fan power box; 40. Filter plate; 41. Collection hole. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but it should not be construed as limiting the scope of protection of the present invention.
[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0025] Example 1
[0026] Please see Figure 1-6 This utility model provides a technical solution: a dustproof grinding device for carbon brush processing, including a carbon brush processing table 1, a processing machine frame 2 fixedly installed on one side of the top of the carbon brush processing table 1, a main controller 3 fixedly installed on the bottom of the front side of one side of the processing machine frame 2, a sliding adjustment groove 4 opened on the top surface of one side of the processing machine frame 2, a drive threaded rod 5 movably installed inside the sliding adjustment groove 4, a sliding top plate 6 movably installed on one side of the drive threaded rod 5, a drive motor 7 fixedly installed on the outer wall of one side of the top of the processing machine frame 2, a motor control connection line 8 fixedly connected between the main controller 3 and the drive motor 7, a servo motor 9 fixedly installed on the bottom of one side of the sliding top plate 6, a lifting rod 10 telescopically connected to the bottom of one side of the servo motor 9, a connecting base 11 fixedly connected to the bottom of one side of the lifting rod 10, an angle adjustment motor 12 fixedly installed on the back side of one side of the connecting base 11, a rotating disk 13 rotatably connected to the front side of one side of the connecting base 11, a connecting rod 14 fixedly connected to one side of the rotating disk 13, and a mounting plate fixedly installed on the top of one side of the connecting rod 14. The mounting plate 15 has a grinding motor 16 fixedly mounted on one side of the back. A rotating shaft 17 is rotatably connected to one side of the mounting plate 15. A grinding wheel 18 is fixedly connected to the top of one side of the rotating shaft 17. The drive motor 7 and the drive threaded rod 5 are connected by a drive connection. The drive motor 7 and the main controller 3 are connected by an electric control connection. The sliding top plate 6 is located inside the sliding adjustment groove 4. The sliding top plate 6 and the sliding adjustment groove 4 are connected by a sliding connection. The drive threaded rod 5 passes through the interior of the sliding top plate 6. The drive threaded rod 5 and the sliding top plate 6 are connected by a threaded drive connection. The servo motor 9 and the lifting rod 10 are connected by a vertical drive telescopic connection. The angle adjustment motor 12 and the rotating plate 13 are connected by a rotation drive connection. The grinding motor 16 and the rotating shaft 17 are connected by a rotation drive connection. A water pipe clamping plate 19 is fixedly mounted on one side of the connecting base 11. A cooling and dust suppression water pipe 20 is movably clamped inside the water pipe clamping plate 19. A water pipe control valve 21 is provided on the top surface of one side of the cooling and dust suppression water pipe 20.
[0027] In the implementation plan, the main controller 3 directly controls the start-up of the drive motor 7, controls the drive threaded rod 5 to drive the sliding top plate 6 to achieve horizontal sliding adjustment position, the servo motor 9 at the bottom of the sliding top plate 6 directly controls the extension and retraction adjustment height of the lifting rod 10, and the angle adjustment motor 12 controls the rotation angle of the rotating disk 13, thereby achieving appropriate adjustment of the use angle of the grinding wheel 18. For the processing of carbon brushes at different angles, the grinding motor 16 drives the rotation of the rotating shaft 17, thereby using the grinding wheel 18 to perform grinding operations on the carbon brushes. During the grinding process, the cooling and dust suppression water pipe 20 is connected to a water body to achieve water spraying operations, thereby achieving cooling and dust suppression operations on the grinding wheel 18.
[0028] Example 2
[0029] Please see Figure 1-6This utility model provides a technical solution: a dustproof grinding device for carbon brush processing, comprising a waste collection bin 22 fixedly installed on the top surface of one side of a carbon brush processing table 1, a processing tray 23 connected to the top surface of one side of the waste collection bin 22, a filter disc 40 fixedly installed inside the processing tray 23, a collection hole 41 opened on the surface of the filter disc 40, a fixed disc 24 fixedly installed on one side of the processing tray 23, a sliding adjustment disc 25 fixedly connected to one side of the fixed disc 24, a sliding limit rail 26 fixedly installed on the inner wall of the sliding adjustment disc 25, and a sliding limit rail 26 slidably connected to one side of the sliding limit rail 26. The sliding base 27 has a fixture 28 fixedly mounted on one side of its top end. A threaded extrusion rod 29 is movably connected to the top surface of the fixture 28. A rotating adjustment handle 30 is fixedly connected to one side of the threaded extrusion rod 29. A connecting bearing 31 is rotatably connected to one side of the bottom end of the threaded extrusion rod 29. A pressing fixing plate 32 is fixedly connected to the bottom end of the connecting bearing 31. A pressing claw plate 33 is fixedly connected to the surface of the fixture 28 near the pressing fixing plate 32. There are two fixing plates 24, symmetrically distributed on both sides of the processing table 23. The sliding base 27 is located at the sliding adjustment... Inside the section disc 25, the sliding base 27 and the sliding adjusting disc 25 are slidably connected. The extrusion threaded rod 29 passes through the top surface of the fixture 28, and the connection between the extrusion threaded rod 29 and the fixture 28 is a threaded connection. The extrusion fixing disc 32 is located between the top of the fixture 28 and the extrusion claw disc 33. The collection holes 41 penetrate the surface of the filter disc 40, and there are several collection holes 41 distributed circumferentially on the surface of the filter disc 40. A cleaning auxiliary chamber door 34 is provided on one side of the waste collection bin 22, and a negative pressure air box 35 is fixedly installed on one side of the waste collection bin 22. The negative pressure fan 36 is installed inside the negative pressure fan box 35. A negative pressure connecting groove 37 is opened on the front side of one side of the negative pressure fan box 35. An external connecting groove 38 is opened on the side surface of the negative pressure fan box 35. A fan power box 39 is fixedly installed on the back of the negative pressure fan box 35. The negative pressure fan box 35 and the waste collection bin 22 are connected through the negative pressure connecting groove 37. The external connecting groove 38 penetrates the interior of the negative pressure fan box 35. There are several external connecting grooves 38, which are symmetrically distributed at equal intervals on both sides of the negative pressure fan box 35. The connection between the fan power box 39 and the negative pressure fan 36 is a power control connection.
[0030] In the implementation plan, the position of the sliding chassis 27 on the sliding limit rail 26 is adjusted to achieve the spacing between the two retainers 28. The spacing is set according to the actual length of the carbon brush. The position of the extrusion threaded rod 29 on the top surface of the retainer 28 is adjusted by rotating the adjustment handle 30. The carbon brush is clamped and fixed by the extrusion fixing plate 32 and the extrusion claw plate 33. The negative pressure is controlled by the negative pressure fan 36 inside the negative pressure air box 35 on the side of the waste collection bucket 22. The grinding waste is directly absorbed into the interior of the waste collection bucket 22 by negative pressure. The collection hole 41 can directly absorb the waste. The waste collection bucket 22 also collects waste liquid. The subsequent cleaning can be carried out by opening the cleaning auxiliary door 34.
[0031] Working principle:
[0032] The position of the sliding base 27 on the sliding limit rail 26 is adjusted to achieve the spacing between the two retainers 28. The spacing is set according to the actual length of the carbon brush. The position of the extrusion threaded rod 29 on the top surface of the retainer 28 is adjusted by rotating the adjustment handle 30. The carbon brush is clamped and fixed by the extrusion fixing plate 32 and the extrusion claw plate 33.
[0033] The main controller 3 directly controls the start-up of the drive motor 7, controls the drive threaded rod 5 to drive the sliding top plate 6 to achieve horizontal sliding adjustment position, and directly controls the extension and retraction adjustment height of the lifting rod 10 through the servo motor 9 at the bottom of the sliding top plate 6. The angle adjustment motor 12 controls the rotation angle of the rotating disk 13, thereby achieving appropriate adjustment of the use angle of the grinding wheel 18. For the processing of carbon brushes at different angles, the grinding motor 16 drives the rotation of the rotating shaft 17, thereby using the grinding wheel 18 to perform grinding operations on the carbon brushes. During the grinding process, the cooling and dust suppression water pipe 20 is connected to water to achieve water spraying operations, thereby achieving cooling and dust suppression operations on the grinding wheel 18.
[0034] During the grinding process, negative pressure control is achieved through the negative pressure fan 36 inside the negative pressure air box 35 on the side of the waste collection bucket 22. The grinding waste is directly absorbed into the interior of the waste collection bucket 22 by negative pressure. The collection hole 41 can directly absorb the waste. The waste collection bucket 22 also collects waste liquid. Afterwards, it can be cleaned by opening the cleaning auxiliary door 34.
[0035] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A dustproof grinding device for carbon brush processing, comprising a carbon brush processing table (1), wherein a processing machine frame (2) is fixedly installed on one side of the top of the carbon brush processing table (1), characterized in that: A main controller (3) is fixedly installed on the bottom of one side of the processing machine frame (2). A sliding adjustment groove (4) is opened on the top surface of one side of the processing machine frame (2). A drive threaded rod (5) is movably installed inside the sliding adjustment groove (4). A sliding top plate (6) is movably installed on one side surface of the drive threaded rod (5). A drive motor (7) is fixedly installed on the outer wall of one side of the top of the processing machine frame (2). A motor control connection line (8) is fixedly connected between the main controller (3) and the drive motor (7). A servo motor (9) is fixedly installed on the bottom of one side of the sliding top plate (6). A lifting device is telescopically connected to the bottom of one side of the servo motor (9). The lifting rod (10) has a connecting base (11) fixedly connected to one side bottom end. An angle adjustment motor (12) is fixedly installed on the back side of one side of the connecting base (11). A rotating disk (13) is rotatably connected to one side of the connecting base (11). A connecting rod (14) is fixedly connected to one side of the rotating disk (13). An installation disk (15) is fixedly installed on one side top of one side of the connecting rod (14). A grinding motor (16) is fixedly installed on the back side of one side of the installation disk (15). A rotating shaft (17) is rotatably connected to one side front of one side of the installation disk (15). A grinding wheel (18) is fixedly connected to one side top of one side of the rotating shaft (17).
2. The dustproof grinding device for carbon brush processing according to claim 1, characterized in that, The drive motor (7) and the drive threaded rod (5) are connected by a drive connection, and the drive motor (7) and the main controller (3) are connected by an electric control connection. The sliding top plate (6) is located inside the sliding adjustment groove (4), and the sliding top plate (6) and the sliding adjustment groove (4) are connected by a sliding connection. The drive threaded rod (5) passes through the interior of the sliding top plate (6), and the drive threaded rod (5) and the sliding top plate (6) are connected by a threaded drive connection.
3. The dustproof grinding device for carbon brush processing according to claim 1, characterized in that, The servo motor (9) and the lifting rod (10) are connected by a vertical drive telescopic connection, the angle adjustment motor (12) and the rotating disk (13) are connected by a rotation drive connection, and the grinding motor (16) and the rotating shaft (17) are connected by a rotation drive connection.
4. The dustproof grinding device for carbon brush processing according to claim 1, characterized in that, A water pipe clamping plate (19) is fixedly installed on one side surface of the connecting chassis (11). A cooling and dust suppression water pipe (20) is movably clamped inside the water pipe clamping plate (19). A water pipe control valve (21) is provided on the top surface of one side of the cooling and dust suppression water pipe (20).
5. The dustproof grinding device for carbon brush processing according to claim 1, characterized in that, A waste collection bin (22) is fixedly installed on the top surface of one side of the carbon brush processing table (1). A processing tray (23) is connected to the top surface of one side of the waste collection bin (22). A filter plate (40) is fixedly installed inside the processing tray (23). A collection hole (41) is opened on the surface of the filter plate (40). A fixed plate (24) is fixedly installed on one side of the processing tray (23). A sliding adjustment plate (25) is fixedly connected to one side of the fixed plate (24). A sliding limit rail (26) is fixedly installed on the inner wall of the sliding adjustment plate (25). A sliding base (27) is slidably connected to one side of the sliding base (27). A retainer (28) is fixedly installed on the top of one side of the sliding base (27). A pressing threaded rod (29) is movably connected to the top surface of the retainer (28). A rotating adjustment handle (30) is fixedly connected to the top of one side of the pressing threaded rod (29). A connecting bearing (31) is rotatably connected to the bottom of one side of the pressing threaded rod (29). A pressing fixing plate (32) is fixedly connected to the bottom of the connecting bearing (31). A pressing claw plate (33) is fixedly connected to the surface of the retainer (28) near the pressing fixing plate (32).
6. The dustproof grinding device for carbon brush processing according to claim 5, characterized in that, There are two fixed disks (24), which are symmetrically distributed on both sides of the processing table (23). The sliding base (27) is located inside the sliding adjustment disk (25). The sliding base (27) and the sliding adjustment disk (25) are slidably connected. The extrusion threaded rod (29) passes through the top surface of the fixture (28). The connection between the extrusion threaded rod (29) and the fixture (28) is a threaded connection. The extrusion fixed disk (32) is located between the top of the fixture (28) and the extrusion claw disk (33). The collection hole (41) passes through the surface of the filter disk (40). There are several collection holes (41), which are circumferentially distributed on the surface of the filter disk (40).
7. The dustproof grinding device for carbon brush processing according to claim 5, characterized in that, A cleaning auxiliary door (34) is provided on one side surface of the waste collection bin (22). A negative pressure air box (35) is fixedly installed on one side of the waste collection bin (22). A negative pressure fan (36) is installed inside the negative pressure air box (35). A negative pressure communication groove (37) is opened on the front side of one side of the negative pressure air box (35). An external communication groove (38) is opened on the side surface of the negative pressure air box (35). A fan power box (39) is fixedly installed on the back of the negative pressure air box (35).
8. The dustproof grinding device for carbon brush processing according to claim 7, characterized in that, The negative pressure air box (35) and the waste collection bucket (22) are connected through the negative pressure connecting groove (37). The external connecting groove (38) penetrates the interior of the negative pressure air box (35). There are several external connecting grooves (38), which are symmetrically distributed at equal intervals on both sides of the negative pressure air box (35). The connection between the fan power box (39) and the negative pressure fan (36) is an electric control connection.