A composite polishing device for gear end face and tooth surface

Abstract

The invention discloses a composite polishing device for gear end faces and tooth surfaces. A uniformly distributed positioning tool is fixed on a conveying chain for supporting and conveying a gear workpiece; a tooth surface polishing mechanism has a rotating shaft horizontally arranged above the positioning tool, and a polishing wheel is fixed on the rotating shaft; when the gear workpiece moves below the polishing wheel, the polishing wheel polishes the tooth surface of the gear workpiece; the end surface polishing mechanism has a pair of polishing belts horizontally arranged below the positioning tool, and when the gear workpiece moves between the two polishing belts, the two polishing belts polish the two side end surfaces of the gear workpiece. The tooth surface polishing mechanism and the end surface polishing mechanism of the invention work simultaneously, and the two polishing belts in the tooth surface polishing mechanism are offset relative to the gear workpiece, and in the process of polishing the end surface of the gear workpiece, the two polishing belts guide and drive the gear workpiece to rotate, and cooperate with the upper end surface polishing mechanism to complete the tooth surface and end surface polishing of the gear workpiece at one time.

Description

Technical Field

[0001] The invention relates to the technical field of grinding and polishing, and in particular to a composite polishing device for gear end faces and tooth surfaces. Background Art

[0002] In the gear manufacturing industry, gear polishing is a key link to ensure its quality and performance. As the core component of the transmission system, the surface finish and precision of the gear directly affect the transmission efficiency and the stability of equipment operation. The traditional gear polishing process usually adopts a step-by-step approach, that is, the tooth surface is polished first, and then the end face is polished. However, this step-by-step polishing method has the following shortcomings:

[0003] Since the tooth surface and end face need to be polished separately, the entire polishing process takes a long time and cannot meet the high efficiency requirements of modern production; in addition, step-by-step polishing may also cause secondary contamination or damage to the gear during the polishing process, increasing the difficulty and cost of subsequent processing. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the present invention provides a composite polishing device for gear end faces and tooth surfaces.

[0005] The present invention adopts the following technical solution: a composite polishing device for gear end face and tooth surface, comprising:

[0006] A horizontally arranged conveyor chain, on which evenly distributed chain plates are fixed;

[0007] A plurality of positioning fixtures are fixedly connected to the chain plates in a one-to-one correspondence, and are used to support and position the gear workpieces that need to be polished;

[0008] Wherein, the positioning tooling comprises:

[0009] A support plate, fixed on the side of the chain plate;

[0010] a pair of inner support shafts rotatably mounted on the side of the support plate;

[0011] A pair of outer support shafts are rotatably mounted on the side of the support plate, the two outer support shafts are located above the inner support shafts and are disposed on both sides of the two inner support shafts;

[0012] The center hole of the gear workpiece is sleeved on the two inner support shafts, and the two outer support shafts are against the peripheral surface of the gear workpiece;

[0013] The composite polishing device also includes:

[0014] A tooth surface polishing mechanism, wherein the tooth surface polishing mechanism has a rotating shaft horizontally arranged above the positioning tool; the rotating shaft is arranged along the moving direction of the positioning tool, and a plurality of evenly distributed polishing wheels are fixedly mounted on the rotating shaft; when the gear workpiece moves below the polishing wheel, the polishing wheel polishes the tooth surface of the gear workpiece;

[0015] The end face polishing mechanism comprises a pair of polishing belts arranged vertically below the positioning tooling, and the polishing belts rotate in the horizontal direction; the polishing belts are arranged along the moving direction of the positioning tooling and are placed on both sides of the gear workpiece; when the gear workpiece moves between the two polishing belts, the two polishing belts polish the end faces on both sides of the gear workpiece.

[0016] Further, the lower end surface of the support plate is provided with a slide groove extending upward;

[0017] The positioning tool also includes:

[0018] A slider is slidably mounted in the slide groove; the inner support shaft is rotatably mounted on the slider;

[0019] A pressing plate, fixed at the opening of the slide groove on the lower end surface of the supporting plate;

[0020] The elastic member is installed between the pressing plate and the sliding block and is used to push the sliding block upward.

[0021] Guide grooves are provided on the inner walls of both sides of the slide groove; guide bars are provided on both sides of the slide block to slide with the guide grooves;

[0022] The elastic member is an arc-shaped elastic plate, and both ends of the elastic plate have bent portions that are bent multiple times, and the bent portions are located in the guide groove.

[0023] An inner support sleeve in contact with the center hole of the gear workpiece is fixedly mounted on the inner support shaft, and both ends of the inner support sleeve have ribs;

[0024] An outer support wheel in contact with the circumferential surface of the gear workpiece is fixedly mounted on the outer support shaft;

[0025] The inner support sleeve is longer than the outer support wheel.

[0026] The two ends of the rotating shaft are rotatably connected to support seats, and one end of the rotating shaft is connected to the driving device through a coupling;

[0027] A spacer sleeve is arranged between adjacent polishing wheels.

[0028] An upper dust collector is installed on the tooth surface polishing mechanism;

[0029] The upper vacuum cleaner comprises an elongated upper shell, the two side surfaces of which are mounted on the two ends of the rotating shaft and fixedly connected to the supporting seats on the corresponding sides; the upper end of the upper shell is connected to the dust collecting device, and the lower end of the upper shell has an elongated air suction port;

[0030] The air suction port is an arc-shaped inwardly contracted structure.

[0031] The end surface polishing mechanism also includes a bottom plate arranged below the polishing belt;

[0032] The two ends of the polishing belt are connected to a driven roller and a driving roller respectively, and the central axes of the driven roller and the driving roller are rotatably mounted on the bottom plate, wherein a sprocket is fixed on the driving roller; the sprocket is connected to the driving device;

[0033] Two rows of pressing rollers are rotatably mounted on the bottom plate. The two rows of pressing rollers are correspondingly arranged in the middle of the polishing belts on both sides, and the pressing rollers press on the polishing belt on one side close to the gear workpiece.

[0034] A lower dust collector is installed on the end surface polishing mechanism;

[0035] The lower vacuum cleaner comprises a strip-shaped lower shell fixed on the lower side of the bottom plate, and the lower end of the lower shell is connected to the dust collecting device; a row of suction holes connected to the lower shell are provided on the bottom plate, and the suction holes are arranged between the two polishing belts.

[0036] The beneficial effects of the present invention are:

[0037] Through the continuous movement of the conveyor chain, the gear workpiece is continuously polished, which improves the production efficiency. In addition, the tooth surface polishing mechanism and the end surface polishing mechanism work simultaneously. The two polishing belts in the tooth surface polishing mechanism are offset relative to the gear workpiece. In the process of polishing the end surface of the gear workpiece, the gear workpiece is guided and driven to rotate. In conjunction with the upper end surface polishing mechanism, the tooth surface and end surface polishing of the gear workpiece can be completed at one time.

[0038] An elastic support mechanism is set in the positioning fixture. Through the sliding of the slider in the slide slot and the pushing effect of the elastic member, the gear workpiece can be quickly positioned and clamped, which enhances the adaptability of the equipment to gears of different sizes. The elastic support mechanism not only simplifies the loading and unloading process, but also improves the stability of the gear workpiece during the polishing process, ensuring the polishing quality.

[0039] The upper vacuum cleaner and the lower vacuum cleaner are closely combined with the tooth surface polishing mechanism and the end surface polishing mechanism, which can effectively collect the smoke and dust generated during the polishing process, ensure the timely collection and treatment of the smoke and dust, and improve the working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 The present invention is a stereoscopic diagram of a composite polishing device for gear end faces and tooth surfaces.

[0042] Figure 2 The present invention is a front view of a composite polishing device for gear end faces and tooth surfaces.

[0043] Figure 3 It is an exploded view of the tooth surface polishing mechanism and the upper dust collector of the present invention.

[0044] Figure 4 It is a left side view of the tooth surface polishing mechanism and the upper dust collector of the present invention.

[0045] Figure 5 It is a stereoscopic view of the end surface polishing mechanism and the lower dust collector of the present invention.

[0046] Figure 6 It is a top view of the end surface polishing mechanism and the lower dust collector of the present invention.

[0047] Figure 7 It is a three-dimensional diagram of the positioning tool of the present invention.

[0048] Figure 8 It is a top view of the positioning tool of the present invention.

[0049] Fig. 9 for Figure 8 Center AA view.

[0050] Description of reference numerals:

[0051] 1. Conveyor chain; 11. Chain plate;

[0052] 2. Positioning tool; 21. Support plate; 211. Slide groove; 212. Guide groove; 22. Inner support shaft; 221. Inner support sleeve; 23. Outer support shaft; 231. Outer support wheel; 24. Slider; 241. Guide strip; 25. Press plate; 26. Elastic member; 261. Bending part;

[0053] 3. Tooth surface polishing mechanism; 31. Rotating shaft; 32. Polishing wheel; 33. Support seat; 34. Coupling; 35. Spacer;

[0054] 4. end surface polishing mechanism; 41. polishing belt; 42. bottom plate; 43. driving roller; 44. driven roller; 45. sprocket; 46. pressure roller;

[0055] 5. upper vacuum cleaner; 51. upper shell; 52. air inlet;

[0056] 6. lower vacuum cleaner; 61. lower housing; 62. air suction hole;

[0057] 7. Gear workpiece. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Embodiment 1:

[0060] like Figure 1 and Figure 2 As shown, the present invention provides a composite polishing device for gear end faces and tooth surfaces, which mainly includes a conveyor chain 1, a positioning fixture 2, a tooth surface polishing mechanism 3 and an end surface polishing mechanism 4. The conveyor chain 1 is arranged horizontally and rotates cyclically, and evenly distributed chain plates 11 for connecting the positioning fixture 2 are fixed on the conveyor chain 1. During operation, the gear workpiece 7 to be polished is positioned on the positioning fixture 2, and driven by the conveyor chain 1, the gear workpiece 7 passes through the tooth surface polishing mechanism 3 and the end surface polishing mechanism 4 at the same time to achieve polishing of the gear workpiece 7. Guide rails for the chain plate 11 are provided at least at the positions of the tooth surface polishing mechanism 3 and the end surface polishing mechanism 4 to ensure the stability of the positioning fixture 2 on the chain plate 11 when passing through the tooth surface polishing mechanism 3 and the end surface polishing mechanism 4.

[0061] The positioning fixture 2 includes a support plate 21, which is fixed to the side of the chain plate 11 through two adapters. A pair of inner support shafts 22 and a pair of outer support shafts 23 are rotatably mounted on the side of the support plate 21. The two outer support shafts 23 are located above the inner support shafts 22 and are disposed on both sides of the two inner support shafts 22. The center hole of the gear workpiece 7 is sleeved on the two inner support shafts 22, and the two outer support shafts 23 are against the circumferential surface of the gear workpiece 7, thereby realizing the positioning of the gear workpiece 7 and also allowing the gear workpiece 7 to rotate.

[0062] Combination Figures 1 to 4As shown, the tooth surface polishing mechanism 3 includes a rotating shaft 31 horizontally arranged above the positioning fixture 2, the rotating shaft 31 is vertically opposite to the gear workpiece 7 passing through the tooth surface polishing mechanism 3, and the rotating shaft 31 is arranged along the moving direction of the gear workpiece 7. Both ends of the rotating shaft 31 are rotatably connected to a support seat 33 through bearings. One end of the rotating shaft 31 is connected to a driving device through a coupling 34, and the rotation of the rotating shaft 31 is controlled by the driving device. The support seat 33 and the driving device are both fixed on the frame of the whole machine.

[0063] A plurality of evenly distributed polishing wheels 32 are fixedly mounted on the rotating shaft 31, and polishing strips are evenly distributed on the polishing wheels 32. Figure 1 and Figure 3 Only one polishing strip on a polishing wheel 32 is shown; each polishing wheel 32 is separated by a spacer 35 mounted on the rotating shaft 31. When the gear workpiece 7 moves below the polishing wheel 32, the polishing strips of the polishing wheel 32 rotate to polish the tooth surface and the gap between the teeth of the gear workpiece 7, thereby removing the defects after machining and improving the finish of the tooth surface and the gap between the teeth of the gear workpiece 7.

[0064] Combination Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, the end surface polishing mechanism 4 includes a bottom plate 42 arranged below the positioning fixture 2, and two polishing belts 41 are arranged on the bottom plate 42. The polishing belts 41 are arranged along the moving direction of the positioning fixture 2 and are placed on both sides of the gear workpiece 7. The two ends of the polishing belt 41 are correspondingly mounted on the driven roller 44 and the driving roller 43, and the central axes of the driven roller 44 and the driving roller 43 are rotatably mounted on the bottom plate 42 through bearings. Among them, sprockets 45 are fixed on the two driving rollers 43, and the sprockets 45 are connected to a driving device. Under the drive of the driving device, the two sprockets 45 rotate in opposite directions. The bottom plate 42 and the driving device are fixed on the whole machine frame.

[0065] In addition, two rows of pressure rollers 46 are rotatably mounted on the bottom plate 42. The two rows of pressure rollers 46 are correspondingly arranged in the middle of the polishing belts 41 on both sides. The pressure rollers 46 press on the polishing belt 41 on the side close to the gear workpiece 7 to ensure that the polishing belt 41 has good contact with the gear workpiece 7. The lower side of the polishing belt 41 is lower than the lowest position of the gear workpiece 7, and the upper side of the polishing belt 41 is higher than the lowest position of the center hole of the gear workpiece 7. When the gear workpiece 7 moves between the two polishing belts 41, the two polishing belts 41 polish the end faces of the gear workpiece 7 on both sides, and drive the gear workpiece 7 to rotate, completing the polishing of the entire end face of the gear workpiece 7; as the gear workpiece 7 rotates, the polishing wheel 32 can also complete the polishing of the tooth surface and the gap between the teeth on the entire circumference of the gear workpiece 7.

[0066] Working process:

[0067] The gear workpiece 7 is mounted on the two inner support shafts 22 in the positioning fixture 2, and the outer support shafts 23 on both sides are pressed on both sides of the gear workpiece 7 to achieve the positioning of the gear workpiece 7;

[0068] As the conveyor chain 1 rotates, the positioning fixture 2 drives the gear workpiece 7 to move toward the tooth surface polishing mechanism 3 and the end surface polishing mechanism 4;

[0069] When the gear workpiece 7 moves between the two polishing belts 41, the polishing belts 41 on both sides begin to polish the end faces of the gear workpiece 7 on both sides; here, the polishing belts 41 on both sides play a role in guiding and stabilizing the gear workpiece 7, and under the polishing action of the polishing belts 41 on both sides, the gear workpiece 7 starts to rotate, thereby completing the polishing of the entire end face of the gear workpiece 7;

[0070] When the gear workpiece 7 moves between the two polishing belts 41 , the polishing wheel 32 starts to polish the tooth surfaces and inter-tooth gaps of the gear workpiece 7 ; as the gear workpiece 7 rotates, the polishing of the tooth surfaces and inter-tooth gaps on the entire circumference of the gear workpiece 7 is gradually completed.

[0071] Embodiment 2:

[0072] Based on the above embodiment 1, Figure 1 , Figure 2 ,as well as Figures 7 to 9 As shown, in order to facilitate the loading and unloading of the gear workpiece 7, the inner support shaft 22 is provided with an elastic support mechanism that can slide up and down.

[0073] The elastic support mechanism includes a slide groove 211 which is provided on the lower end surface of the support plate 21 and extends upward, and guide grooves 212 are provided on the inner walls on both sides of the slide groove 211. The two inner support shafts 22 are rotatably installed on the slider 24, and the slider 24 is slidably installed in the slide groove 211. Both sides of the slider 24 have guide bars 241 which are slidably matched with the guide groove 212. The guide bars 241 and the guide groove 212 improve the stability of the slider 24 sliding up and down. The pressing plate 25 is fixed on the lower end surface of the support plate 21 and blocks the opening of the slide groove 211 to prevent the slider 24 from falling off. The elastic member 26 is installed between the pressing plate 25 and the slider 24 to push the slider 24 upward.

[0074] In this embodiment, the elastic member 26 is an arc-shaped elastic plate, the middle part of the elastic plate bulges upward and abuts against the lower side of the slider 24, and the two ends of the elastic plate have bent portions 261 that are bent multiple times. The bent portions 261 on both sides are located in the guide grooves 212 on both sides. When the elastic plate is deformed, the bent portions 261 can stretch accordingly, and the two side ends of the elastic member 26 are always kept in the guide grooves 212, thereby realizing the positioning of the bent portions 261.

[0075] In this embodiment, an inner support sleeve 221 is mounted on the inner support shaft, and both ends of the inner support sleeve 221 have ribs; an outer support wheel 231 is mounted and fixed on the outer support shaft 23 , wherein the inner support sleeve 221 is longer than the outer support wheel 231 .

[0076] When installing the gear workpiece 7, the gear workpiece 7 is sleeved on the two inner support sleeves 221 and pressed downward to make the slider 24 slide down; then, the gear workpiece 7 is pushed inward until the gear workpiece 7 abuts against the inner rib of the inner support sleeve 221; finally, the gear workpiece 7 is released, and under the action of the elastic member 26, the slider 24 slides upward, so that the inner support shaft 22 pushes the gear workpiece 7 upward and abuts against the outer support wheels 231 on both sides above, thereby completing the positioning of the gear workpiece 7;

[0077] When removing the gear workpiece 7, press the gear workpiece 7 downward and then drag it outward.

[0078] Embodiment three:

[0079] Based on the above embodiment 2, combined with Figures 1 to 6 As shown, this embodiment is provided with an upper dust collector 5 and a lower dust collector 6 for processing the smoke generated during the polishing process.

[0080] Combination Figures 1 to 4 As shown, Figure 1 The front side of the upper shell 51 is hidden in the figure. The upper vacuum cleaner 5 includes an elongated upper shell 51. The two side surfaces of the upper shell 51 are mounted on the two ends of the rotating shaft 31 and fixedly connected to the support seat 33 on the corresponding side. The upper end of the upper shell 51 is connected to a dust suction device, and the lower end of the upper shell 51 has an elongated air suction port 52. The air suction port 52 is directly opposite to the upper side of the gear workpiece 7. The air suction port 52 is an arc-shaped inward-retracted structure that wraps around the polishing wheel 32 to reduce the width of the air suction port 52. During the polishing process of the polishing wheel 32 on the gear workpiece 7, the dust suction device controls the air suction port 52 to suck air, and the smoke and dust generated during the polishing process are sucked into the dust suction device.

[0081] Combination Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, the lower dust collector 6 includes a long strip lower shell 61 fixed to the lower side of the bottom plate 42, and the lower end of the lower shell 61 is connected to the dust collecting device. A row of suction holes 62 connected to the lower shell 61 are provided on the bottom plate 42, and the suction holes 62 face the lower side of the gear workpiece 7. During the polishing process of the polishing belts 41 on both sides of the gear workpiece 7, the dust collecting device controls the suction holes 62 to suck air, and sucks the smoke and dust generated during the polishing process into the dust collecting device.

[0082] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A composite polishing device for gear end faces and tooth surfaces, characterized in that: include: A horizontally arranged conveyor chain (1), wherein evenly distributed chain plates (11) are fixed on the conveyor chain (1); A plurality of positioning fixtures (2) are fixedly connected to the chain plates (11) in a one-to-one correspondence, and are used to support and position the gear workpiece (7) that needs to be polished; Wherein, the positioning tool (2) comprises: A support plate (21) fixed on a side of the chain plate (11); A pair of inner support shafts (22) rotatably mounted on the side of the support plate (21); A pair of outer support shafts (23) rotatably mounted on the side of the support plate (21), the two outer support shafts (23) being located above the inner support shafts (22) and disposed on both sides of the two inner support shafts (22); The center hole of the gear workpiece (7) is sleeved on the two inner support shafts (22), and the two outer support shafts (23) are against the circumferential surface of the gear workpiece (7); The composite polishing device also includes: A tooth surface polishing mechanism (3), the tooth surface polishing mechanism (3) comprising a rotating shaft (31) arranged horizontally above the positioning fixture (2); the rotating shaft (31) is arranged along the moving direction of the positioning fixture (2), and a plurality of evenly distributed polishing wheels (32) are fixedly mounted on the rotating shaft (31); when the gear workpiece (7) moves below the polishing wheel (32), the polishing wheel (32) polishes the tooth surface of the gear workpiece (7); An end surface polishing mechanism (4), the end surface polishing mechanism (4) comprising a pair of polishing belts (41) vertically arranged below the positioning tool (2), the polishing belts (41) rotating in a horizontal direction; the polishing belts (41) are arranged along the moving direction of the positioning tool (2) and are disposed on both sides of the gear workpiece (7); when the gear workpiece (7) moves between the two polishing belts (41), the two polishing belts (41) polish the end surfaces on both sides of the gear workpiece (7); The lower end surface of the support plate (21) is provided with a sliding groove (211) extending upward; The positioning tool (2) also includes: A sliding block (24) is slidably mounted in the sliding groove (211); the inner support shaft (22) is rotatably mounted on the sliding block (24); A pressing plate (25) fixed at the opening of the slide groove (211) on the lower end surface of the support plate (21); An elastic member (26) is installed between the pressure plate (25) and the slider (24) and is used to push the slider (24) upwards; Guide grooves (212) are provided on the inner walls of both sides of the slide groove (211); and guide bars (241) are provided on both sides of the slide block (24) for sliding engagement with the guide grooves (212); The elastic member (26) is an arc-shaped elastic plate, and both ends of the elastic plate have bent portions (261) that are bent multiple times, and the bent portions (261) are located in the guide groove (212); Both ends of the rotating shaft (31) are rotatably connected to support seats (33), and one end of the rotating shaft (31) is connected to a driving device via a coupling (34); A spacer sleeve (35) is disposed between adjacent polishing wheels (32); An upper dust collector (5) is installed on the tooth surface polishing mechanism (3); The upper vacuum cleaner (5) comprises an upper shell (51) in the shape of an elongated strip, and the two side surfaces of the upper shell (51) are mounted on the two ends of the rotating shaft (31) and are fixedly connected to the support seats (33) on the corresponding sides; the upper end of the upper shell (51) is connected to the vacuum device, and the lower end of the upper shell (51) has an elongated air suction port (52); The air suction port (52) is an arc-shaped inward-retracted structure.

2. A composite polishing device for gear end faces and tooth surfaces according to claim 1, characterized in that: An inner support sleeve (221) in contact with the center hole of the gear workpiece (7) is fixedly mounted on the inner support shaft (22), and both ends of the inner support sleeve (221) have ribs; An outer support wheel (231) in contact with the circumferential surface of the gear workpiece (7) is fixedly mounted on the outer support shaft (23); The inner support sleeve (221) is longer than the outer support wheel (231).

3. A composite polishing device for gear end faces and tooth surfaces according to claim 1, characterized in that: The end surface polishing mechanism (4) further comprises a bottom plate (42) arranged below the polishing belt (41); The two ends of the polishing belt (41) are correspondingly connected to a driven roller (44) and a driving roller (43); the central axes of the driven roller (44) and the driving roller (43) are rotatably mounted on the bottom plate (42); a sprocket (45) is fixed on the driving roller (43); the sprocket (45) is connected to a driving device; Two rows of pressure rollers (46) are rotatably mounted on the bottom plate (42). The two rows of pressure rollers (46) are correspondingly arranged in the middle of the polishing belts (41) on both sides. The pressure rollers (46) press on the polishing belt (41) on the side close to the gear workpiece (7).

4. A composite polishing device for gear end faces and tooth surfaces according to claim 3, characterized in that: A lower dust collector (6) is installed on the end surface polishing mechanism (4); The lower dust collector (6) comprises a strip-shaped lower shell (61) fixed to the lower side of the bottom plate (42), the lower end of the lower shell (61) being connected to a dust collecting device; a row of air suction holes (62) connected to the lower shell (61) are provided on the bottom plate (42), and the air suction holes (62) are arranged between the two polishing belts (41).

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