CN211760537U

CN211760537U - High-efficient polishing equipment of work piece

Info

Publication number: CN211760537U
Application number: CN201922165716.8U
Authority: CN
Inventors: 程卫生
Original assignee: Suzhou Leqi Electromechanical Technology Co ltd
Current assignee: Suzhou Leqi Electromechanical Technology Co ltd
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2020-10-27
Anticipated expiration: 2029-11-29

Abstract

The utility model discloses a high-efficient polishing equipment of work piece, including rough polishing area and meticulous polishing area, the parallel left side at the meticulous polishing area is installed to the rough polishing area, both sides are provided with quick-witted case A and quick-witted case B respectively around between rough polishing area and the meticulous polishing area, it has a polishing area suppression device all to increase in the middle of the polishing area of depositing and meticulous polishing area center department through at the high-efficient polishing equipment of this work piece, and this neotype polishing area suppression device's bottom all through screw and workstation fixed connection, and can change respectively through two neotype polishing area suppression devices and deposit the elasticity degree of polishing area and meticulous polishing area when using, when rough polishing area and meticulous polishing area produce not hard up because under the influence of factors such as live time overlength and ageing and when becoming flexible, can both make to produce not hard up rough polishing area and meticulous polishing area again through adjusting two polishing area suppression devices and resume work under the state of compacting again this moment.

Description

High-efficient polishing equipment of work piece

Technical Field

The utility model belongs to the technical field of the polishing equipment is relevant, concretely relates to high-efficient polishing equipment of work piece.

Background

Polishing means a processing method for obtaining a bright and flat surface by reducing the surface roughness of a work by the action of a mechanical, chemical or electrochemical means, which is a method for obtaining a bright and flat surface by modifying the surface of a work by a polishing tool and abrasive particles or other polishing media, and which cannot improve the dimensional accuracy or geometric accuracy of the work but aims to obtain a smooth surface or a mirror surface gloss, and sometimes eliminates gloss (dulling), and generally uses a polishing wheel as a polishing tool, which is generally formed by stacking a plurality of layers of canvas, felt or leather, and is clamped at both sides by metal disks, and a rim thereof is coated with a polishing agent formed by uniformly mixing a fine abrasive and grease, and when polishing, the polishing wheel rotating at a high speed (the peripheral speed is more than 20 m/sec) is pressed against the work to cause the abrasive to roll and cut a minute amount on the surface of the work, thereby obtaining a bright processed surface, the surface roughness can reach Ra0.63-0.01 microns generally, when a non-greasy extinction polishing agent is adopted, the bright surface can be extinguished to improve the appearance, and when the bearing steel balls are produced in large batches, a roller polishing method is often adopted.

The prior art of high-efficiency workpiece polishing equipment has the following problems: present high-efficient polishing equipment of work piece all need place the work piece and carry out the polishing operation on the polishing belt when carrying out the polishing operation, and the work of polishing belt relies on the motor to carry out the transmission to the driving wheel and just can drive the high-speed rotation of polishing belt, and the polishing belt is when using receive the influence of factors such as length of use and ageing easily and produce not hard up, in case the polishing belt produces not hard up then can cause the polishing belt to produce the shake when high-speed rotation easily, and the polishing belt produces the shake at the during operation and then can influence the normal polishing process to the work piece, the polishing belt of shake simultaneously also can get rid of user's hand easily and cause the user to be injured at the during operation.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a high-efficient polishing equipment of work piece to the polishing belt that provides in solving above-mentioned background art receives the influence of the long and ageing isoparametric of use easily and produces not hard up when using, produces not hard up in case the polishing belt and then can cause the polishing belt to produce the shake when high-speed rotation easily, and the polishing belt produces the shake at the during operation and then can influence the problem to the normal polishing process of work piece.

In order to achieve the above object, the utility model provides a following technical scheme: a high-efficiency workpiece polishing device comprises a rough polishing belt and a fine polishing belt, wherein the rough polishing belt is arranged on the parallel left side of the fine polishing belt, a case A and a case B are respectively arranged on the front side and the rear side between the rough polishing belt and the fine polishing belt, the bottoms of the case A and the case B are provided with a workbench which is transversely parallel, the interiors of the front end and the rear end of the rough polishing belt and the interior of the rear end and the front end and the interior of the rear end of the fine polishing belt are respectively provided with a driving wheel and a driven wheel, the interiors of the driving wheel and the driven wheel are respectively provided with a transverse driving shaft and a transverse driven shaft, the left ends and the right ends of the two driving shafts and the left ends and the right ends of the two driven shafts are respectively arranged outside the left ends and the right ends of the rough polishing belt and the fine polishing, the bottoms of the eight support frames are fixedly connected with a workbench through bolts, polishing belt restraining devices are arranged in the transverse inner parts of the centers of the rough polishing belt and the fine polishing belt, the bottoms of the two polishing belt restraining devices are fixedly connected with the outer wall of the upper end of the workbench, two vertical support rods are arranged on the polishing belt restraining devices in the rough polishing belt and are respectively arranged outside the left side and the right side of the rough polishing belt, the bottoms of the two vertical support rods are fixedly connected with the workbench through screws, the uppermost ends of the two vertical support rods are connected with a top frame, the top frame is transversely arranged in the middle of the rough polishing belt, inwards concave lifting chutes are respectively arranged in the opposite directions of the two vertical support rods, the two lifting chutes are close to the lower side and are internally connected with transverse connecting shafts, and restraining rollers are sleeved outside the connecting shafts between the two vertical support rods, restrain cylinder and connecting axle and pass through fixing bearing fixed connection, all be provided with the connecting rod on the outer wall of the connecting axle left and right sides upper end, two the connecting rod upper end is connected with horizontal connection horizontal pole, it is provided with vertical adjusting screw to connect horizontal pole upper end center department, adjusting screw passes the roof-rack and sets up in the roof-rack upper end outside the top, the adjusting screw outside of roof-rack upside has cup jointed the regulation swivel nut.

Preferably, the polishing motors are arranged inside the case A and the case B, the outermost ends of output shafts of the two polishing motors are connected with connecting seats, the two connecting seats are fixedly connected with one ends of the two driving shafts respectively, and the two polishing motors are electrically connected through an external power supply.

Preferably, workstation bottom four corners department all is provided with vertical pillar, four all through welded fastening connection, four between pillar and the workstation the pillar is close to the downside and all is connected with the link each other, four the pillar all is the right angle state with the workstation.

Preferably, the shape and size of the rough polishing belt and the fine polishing belt are the same, the rough polishing belt and the fine polishing belt are kept in a parallel state, and the installation directions of the driving wheel and the driven wheel in the rough polishing belt and the fine polishing belt are opposite.

Preferably, the restraining roller is of a cylindrical structure, the surface of the restraining roller is a smooth wall, and the outer wall of the top of the restraining roller can be completely attached to the outer wall of the bottom center of the rough polishing belt.

Preferably, the driving wheels and the driven wheels in the two ends of the rough polishing belt and the fine polishing belt are respectively provided with two driving wheels, and the outer walls of the outer sides of the two driving wheels and the driven wheels in the two ends of the rough polishing belt and the fine polishing belt are respectively parallel and level with the left end and the right end of the rough polishing belt and the fine polishing belt.

Compared with the prior art, the utility model provides a high-efficient polishing equipment of work piece possesses following beneficial effect:

1. the utility model adds a polishing belt restraining device in the middle of the center of the storage polishing belt and the center of the fine polishing belt of the high-efficiency polishing equipment for workpieces, the bottom of the novel polishing belt restraining device is fixedly connected with the workbench through screws, and the tightness of the storage polishing belt and the tightness of the fine polishing belt can be respectively changed through the two novel polishing belt restraining devices, so that when the rough polishing belt and the fine polishing belt are loosened due to the influence of factors such as overlong use time, aging and the like, the rough polishing belt and the fine polishing belt which are loosened can be restored to the compact state again to continue working by adjusting the two polishing belt restraining devices, thus avoiding economic loss caused by directly replacing the polishing belts, and complicated operation of tightening and adjusting by independently taking down the polishing belts, the two polishing belt restraining devices can respectively change the tightness of the rough polishing belt and the tightness of the fine polishing belt according to the polishing requirements of the polishing workpiece, so that the use flexibility of the polishing equipment is improved;

2. the specific application mode and principle of the polishing belt restraining device of the utility model are as follows, taking the polishing belt restraining device on the rough polishing belt as an example, when the rough polishing belt is loosened due to the influence of factors such as overlong service time or aging, the rough polishing belt is easily greatly shaken during working if the rough polishing belt is not adjusted timely, thereby affecting the normal polishing of the workpiece, at the moment, the loosened rough polishing belt is required to be restored to the original compact state again by adjusting the polishing belt restraining device, only one movable spanner sleeve needs to be connected to the outside of the adjusting screw sleeve on the polishing belt restraining device and rotates clockwise during operation, the adjusting screw sleeve rotating clockwise at the moment can pull the adjusting screw rod upwards through threads under the blocking of the top frame, and the connecting cross rod is driven to vertically rise when the adjusting screw rod moves upwards, once the connecting cross rod moves upwards, the connecting shaft is driven by the two connecting rods, the inhibiting rollers are fixedly sleeved outside the connecting shaft through the fixed bearings and are arranged outside the lowest end of the center of the rough polishing belt, so when the connecting shaft rises, the inhibiting rollers are driven to cling to the outer wall of the bottom of the rough polishing belt, and when the connecting shaft continues rising, the bottom of the rough polishing belt is pulled upwards through the inhibiting rollers, once the rising inhibiting rollers form upward tension on the center of the bottom of the rough polishing belt, the rough polishing belt which originally loosens is inhibited by the inhibiting rollers and returns to a compact state to work, and the inhibiting rollers are cylindrical and cling to the bottom of the rough polishing belt, so when the rough polishing belt works, the inhibiting rollers are synchronously driven to inhibit the rotation of the rollers, and therefore, the inhibiting rollers can change the tightness degree of the rough polishing belt, meanwhile, the normal use of the rough polishing belt is not influenced.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description, do not constitute a limitation of the invention, in which:

FIG. 1 is a schematic view of a three-dimensional structure of a high-efficiency polishing apparatus for workpieces according to the present invention;

FIG. 2 is a schematic view of a top plan structure of the high-efficiency polishing apparatus for workpieces according to the present invention;

FIG. 3 is a schematic view of the cross-sectional structure of the polishing belt restraining device according to the present invention;

fig. 4 is a schematic plan view of the polishing belt restraining device according to the present invention;

in the figure: 1. a pillar; 2. a connecting frame; 3. a work table; 4. a support frame; 5. a driving wheel; 6. a rough polishing belt; 7. a case A; 8. a fine polishing belt; 9. a polishing belt restraining device; 10. A support shaft seat; 11. a driven wheel; 12. a case B; 13. a drive shaft; 14. a connecting seat; 15. Polishing the motor; 16. a driven shaft; 17. a vertical support bar; 18. a connecting rod; 19. a restraining drum; 20. a connecting shaft; 21. fixing the bearing; 22. connecting the cross bars; 23. a lifting chute; 24. A top frame; 25. adjusting the screw rod; 26. and adjusting the threaded sleeve.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides a technical solution: a high-efficiency workpiece polishing device comprises a rough polishing belt 6 and a fine polishing belt 8, wherein the rough polishing belt 6 is arranged on the parallel left side of the fine polishing belt 8, a case A7 and a case B12 are respectively arranged on the front side and the rear side between the rough polishing belt 6 and the fine polishing belt 8, the shapes and the sizes of the rough polishing belt 6 and the fine polishing belt 8 are the same, the rough polishing belt 6 and the fine polishing belt 8 are kept in a parallel state, the driving wheels 5 and the driven wheels 11 inside the rough polishing belt 6 and the fine polishing belt 8 are opposite in installation direction, the driving wheels 5 and the driven wheels 11 inside the two ends of the rough polishing belt 6 and the fine polishing belt 8 are respectively arranged, the two driving wheels 5 and the outer walls outside the driven wheels 11 inside the two ends of the rough polishing belt 6 and the fine polishing belt 8 are respectively kept at the same level with the left end and the right end of the rough polishing belt 6 and the fine polishing belt 8, the rough polishing, the fine polishing belt 8 can perform fine polishing operation on a workpiece, the surface of the workpiece can be polished to form a smooth plane, so that the workpiece can be polished to form a finished product meeting requirements, the bottom of the case A7 and the bottom of the case B12 are provided with the workbench 3 which are transversely parallel, the four corners of the bottom of the workbench 3 are respectively provided with the vertical pillars 1, the four pillars 1 are fixedly connected with the workbench 3 by welding, the lower sides of the four pillars 1 which are close to each other are respectively connected with the connecting frame 2, the four pillars 1 are respectively in a right-angle state with the workbench 3, the four pillars 1 are respectively welded to enable the pillars 1 to be more firmly connected and fixed with the workbench 3, so that the workbench 3 can be more stably placed on the ground through the pillars 1 and can bear larger weight, the polishing motors 15 are arranged inside the case A7 and the case B12, the outermost ends of output shafts of two polishing motors 15 are respectively connected with a connecting seat 14, the two connecting seats 14 are respectively fixedly connected with one end of two driving shafts 13, the two polishing motors 15 are electrically connected through an external power supply, the inner parts of the front and back ends of a rough polishing belt 6 and the inner parts of the front and back ends of a fine polishing belt 8 are respectively provided with a driving wheel 5 and a driven wheel 11, the inner parts of the two driving wheels 5 and the two driven wheels 11 are respectively provided with a transverse driving shaft 13 and a transverse driven shaft 16, the left and right ends of the two driving shafts 13 and the two driven shafts 16 are respectively arranged at the outer parts of the left and right ends of the rough polishing belt 6 and the fine polishing belt 8, the outer parts of the left and right ends of the two driving shafts 13 and the two driven shafts 16 are respectively provided with a supporting shaft seat 10, the bottom parts of, the horizontal inside of 8 center departments of rough polishing area 6 and meticulous polishing area all is provided with polishing area suppression device 9, the bottom of two polishing area suppression device 9 all with 3 upper end outer wall fixed connection of workstation, can change respectively through two neotype polishing area suppression device 9 and deposit the elasticity degree of polishing area and meticulous polishing area 8 when using, when rough polishing area 6 and meticulous polishing area 8 produce not hard up because under the influence of factors such as live time overlength and ageing, can both make to produce not hard up rough polishing area 6 and meticulous polishing area 8 and resume work under the state of compacting again through adjusting two polishing area suppression device 9 this moment, can avoid the economic loss that the direct change polishing area brought like this, and need take off the polishing area alone to carry out the loaded down with trivial details operation of tight regulation.

A high-efficiency polishing device for workpieces is characterized in that a polishing belt restraining device 9 in a rough polishing belt 6 is provided with two vertical support rods 17, the two vertical support rods 17 are respectively arranged at the outer parts of the left side and the right side of the rough polishing belt 6, the bottoms of the two vertical support rods 17 are fixedly connected with a workbench 3 through screws, the uppermost ends of the two vertical support rods 17 are connected with a top frame 24, the top frame 24 is transversely arranged in the middle of the rough polishing belt 6, inwards concave lifting chutes 23 are respectively arranged in the opposite directions of the two vertical support rods 17, the two lifting chutes 23 are connected with a transverse connecting shaft 20 close to the lower side, a restraining roller 19 is sleeved at the outer part of the connecting shaft 20 between the two vertical support rods 17, the restraining roller 19 is fixedly connected with the connecting shaft 20 through a fixed bearing 21, connecting rods 18 are respectively arranged on the outer walls of the upper ends of the, a vertical adjusting screw 25 is arranged at the center of the upper end of the connecting cross rod 22, the uppermost end of the adjusting screw 25 penetrates through the top frame 24 and is arranged outside the upper end of the top frame 24, an adjusting threaded sleeve 26 is sleeved outside the adjusting screw 25 on the upper side of the top frame 24, the restraining roller 19 is of a cylindrical structure, the surface of the restraining roller 19 is a smooth and smooth wall, the outer wall of the top of the restraining roller 19 can be completely attached to the outer wall of the center of the bottom of the rough polishing belt 6, only one movable wrench sleeve needs to be connected to the outside of the adjusting threaded sleeve 26 on the polishing belt restraining device 9 and rotates clockwise during operation, the adjusting threaded sleeve 26 rotating clockwise at the moment can pull the adjusting screw 25 upwards through threads under the blocking of the top frame 24, the adjusting screw 25 can drive the connecting cross rod 22 to vertically ascend upwards when moving upwards, and the connecting cross rod 22 can drive the connecting shaft 20 through the two connecting rods 18 once moving upwards, since the connecting shaft 20 is fixedly sleeved with the restraining roller 19 through the fixed bearing 21, and the restraining roller 19 is arranged outside the lowest end of the center of the rough polishing belt 6, when the connecting shaft 20 ascends, the restraining roller 19 is driven to cling to the outer wall of the bottom of the rough polishing belt 6, and when the connecting shaft 20 continuously ascends, the bottom of the rough polishing belt 6 is pulled upwards through the restraining roller 19, once the ascending restraining roller 19 forms an upward pulling force on the center of the bottom of the rough polishing belt 6, the rough polishing belt 6 which originally loosens is restrained by the restraining roller 19 and returns to a compact state to work, and the restraining roller 19 is cylindrical and clings to the bottom of the rough polishing belt 6, so the restraining roller 19 is synchronously driven to rotate when the rough polishing belt 6 works, so that the restraining roller 19 can change the tightness of the rough polishing belt 6, while not affecting the normal use of the rough polishing belt 6.

The utility model discloses a theory of operation and use flow: the utility model discloses install the back, use this high-efficient polishing equipment of work piece and use, at first need lay polishing workshop to whole polishing equipment through four pillars 1 of 3 bottoms of workstation, then need be switched on for whole polishing equipment and use, at this polishing equipment on-line working, the inside polishing motor 15 of machine case A7 and machine case B12 then can drive two driving shafts 13 and the outside action wheel 5 of driving shaft 13 respectively through the connection transmission of connecting seat 14 and rotate at a high speed this moment, and the model that two polishing motors 15 adopted is: GB/T4942.1-2001, because two driving wheels 5 are respectively sleeved inside the front end of a rough polishing belt 6 and inside the rear end of a fine polishing belt 8, and driven wheels 11 are respectively installed inside the rear side of the rough polishing belt 6 and inside the front side of the fine polishing belt 8, two groups of driving wheels 5 respectively driven by two polishing motors 15 can respectively drive the rough polishing belt 6 and the fine polishing belt 8 to be in a high-speed state, so that when a workpiece needs to be polished, the workpiece only needs to be firstly placed on the rough polishing belt 6 for rough polishing at the moment, the workpiece only needs to be placed on the fine polishing belt 8 for fine polishing after the rough polishing is completed, the outer part of the polished workpiece is smooth and bright until the workpiece meets the polishing requirements, and a polishing belt inhibiting device 9 is additionally arranged between the centers of the rough polishing belt and the fine polishing belt 8 of the high-efficiency workpiece polishing equipment, and this neotype polishing belt suppression device 9's bottom all passes through screw and 3 fixed connection of workstation, and can change respectively through two neotype polishing belt suppression device 9 and deposit the elasticity degree of polishing belt and meticulous polishing belt 8 when using, when rough polishing belt 6 and meticulous polishing belt 8 produce not hard up because under the influence of factors such as live time overlength and ageing, can both make to produce not hard up rough polishing belt 6 and meticulous polishing belt 8 and resume work under the state of compacting again through adjusting two polishing belt suppression device 9 this moment, can avoid directly changing the economic loss that the polishing belt brought like this.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A high-efficiency workpiece polishing device comprises a rough polishing belt (6) and a fine polishing belt (8), and is characterized in that: the rough polishing belt (6) is arranged on the left side of the fine polishing belt (8) in parallel, a case A (7) and a case B (12) are respectively arranged on the front side and the rear side between the rough polishing belt (6) and the fine polishing belt (8), a transverse parallel workbench (3) is arranged at the bottom of the case A (7) and the case B (12), a driving wheel (5) and a driven wheel (11) are respectively arranged inside the front end and the rear end of the rough polishing belt (6) and inside the rear end and the front end of the fine polishing belt (8), a transverse driving shaft (13) and a transverse driven shaft (16) are respectively arranged inside the driving wheel (5) and the driven wheel (11), the left ends and the right ends of the two driving shafts (13) and the two driven shafts (16) are respectively arranged outside the left end and the right end of the rough polishing belt (6) and the fine polishing belt (8), and the left ends and the right ends of the two driving shafts (13) and the two driven shafts (, the bottom of each of the eight supporting shaft seats (10) is provided with a vertical supporting frame (4), the bottom of each of the eight supporting frames (4) is fixedly connected with the workbench (3) through a bolt, the horizontal inner parts of the centers of the rough polishing belt (6) and the fine polishing belt (8) are respectively provided with a polishing belt restraining device (9), the bottoms of the two polishing belt restraining devices (9) are respectively fixedly connected with the outer wall of the upper end of the workbench (3), the polishing belt restraining device (9) in the rough polishing belt (6) is provided with two vertical supporting rods (17), the two vertical supporting rods (17) are respectively arranged on the outer parts of the left side and the right side of the rough polishing belt (6), the bottoms of the two vertical supporting rods (17) are respectively fixedly connected with the workbench (3) through screws, the uppermost ends of the two vertical supporting rods (17) are connected with a top frame (24), the top frame (24) is horizontally arranged in the middle of the rough polishing belt, inwards sunken lifting chutes (23) are respectively arranged in the opposite directions of the two vertical supporting rods (17), the two lifting chutes (23) are internally connected with a transverse connecting shaft (20) close to the lower side, a restraining roller (19) is sleeved outside the connecting shaft (20) between the two vertical supporting rods (17), the restraining roller (19) and the connecting shaft (20) are fixedly connected through a fixed bearing (21), the outer walls of the upper ends of the left side and the right side of the connecting shaft (20) are respectively provided with a connecting rod (18), the upper ends of the two connecting rods (18) are connected with a transverse connecting cross rod (22), a vertical adjusting screw rod (25) is arranged at the center of the upper end of the connecting cross rod (22), the uppermost end of the adjusting screw rod (25) passes through the top frame (24) and is arranged outside the upper end of the top frame (24), an adjusting threaded sleeve (26) is sleeved outside the adjusting screw rod (25) on the upper side of the top frame (24).

2. A workpiece high-efficiency polishing apparatus according to claim 1, characterized in that: the polishing machine is characterized in that polishing motors (15) are arranged inside the machine case A (7) and the machine case B (12), the outermost ends of output shafts of the polishing motors (15) are connected with connecting seats (14), the two connecting seats (14) are fixedly connected with one ends of the two driving shafts (13) respectively, and the two polishing motors (15) are electrically connected through an external power supply.

3. A workpiece high-efficiency polishing apparatus according to claim 1, characterized in that: workstation (3) bottom four corners department all is provided with vertical pillar (1), four all through welded fastening connection, four between pillar (1) and workstation (3) pillar (1) are close to the downside and all are connected with link (2), four each other pillar (1) all are the right angle state with workstation (3).

4. A workpiece high-efficiency polishing apparatus according to claim 1, characterized in that: the shape and the size of the rough polishing belt (6) and the size of the fine polishing belt (8) are the same, the rough polishing belt (6) and the fine polishing belt (8) are kept in a parallel state, and the driving wheel (5) and the driven wheel (11) in the rough polishing belt (6) and the fine polishing belt (8) are installed in opposite directions.

5. A workpiece high-efficiency polishing apparatus according to claim 1, characterized in that: the inhibition roller (19) is of a cylindrical structure, the surface of the inhibition roller (19) is a smooth wall, and the outer wall of the top of the inhibition roller (19) can be completely attached to the outer wall of the bottom center of the rough polishing belt (6).

6. A workpiece high-efficiency polishing apparatus according to claim 1, characterized in that: the driving wheel (5) and the driven wheel (11) in the two ends of the rough polishing belt (6) and the fine polishing belt (8) are respectively provided with two driving wheels, and the outer walls of the two driving wheels (5) and the outer sides of the driven wheel (11) in the two ends of the rough polishing belt (6) and the fine polishing belt (8) are respectively kept parallel and level with the left end and the right end of the rough polishing belt (6) and the fine polishing belt (8).