Dustproof polishing head with dustproof assembly

Abstract

The present application relates to the technical field of polishing head, particularly to a dust blocking assembly and a dustproof polishing head, which comprises a first shell, a second shell coaxially arranged with the first shell, the outer diameter of the second shell being smaller than the inner diameter of the first shell, the first shell or the second shell rotating around the axis of the second shell, a transition chamber being formed between the first shell and the second shell, and a dust blocking piece arranged in the transition chamber and used for plugging the space interval between the first shell and the second shell. The first shell and the second shell are coaxially arranged to form the transition chamber, the dust blocking piece can accurately plug the space interval between the two shells, dust intrusion is blocked from the source, and the pertinence of sealing protection is greatly improved. The design of the transition chamber provides a buffer area for dust, avoids direct impact of dust on the core sealing structure, and reduces the wear speed of the sealing piece.

Description

Technical Field

[0001] This invention relates to the field of grinding head technology, and in particular to a dustproof assembly and a dustproof grinding head. Background Technology

[0002] In industries such as construction and decoration, and furniture manufacturing, grinding heads are core equipment components used for sanding surfaces such as walls and panels. Their working principle involves a drive unit that rotates a grinding disc at high speed, causing the sandpaper on the disc to contact and rub against the surface to be sanded, achieving a smooth surface finish. However, the sanding process inevitably generates a large amount of dust. This dust not only pollutes the working environment and harms the health of operators, but also seriously affects the working stability of the grinding head itself. Current technologies typically incorporate dust collection devices and sealing structures to address the dust problem, but these solutions still have several shortcomings in practical applications. Firstly, existing sealing structures often use simple brush designs with insufficient sealing performance, allowing dust to easily penetrate the grinding head through gaps in the housing. Secondly, the housing of grinding heads is often a cylindrical structure, lacking dust guidance capabilities, causing dust to accumulate at the sealing edges, gradually forming dust bridges that eventually break through the sealing barrier and enter the transmission component area. Summary of the Invention

[0003] In this section, as well as in the abstract and title of this application, some simplifications or omissions may be made to avoid obscuring the purpose of this section, the abstract, and the title of this application, and such simplifications or omissions shall not be used to limit the scope of the invention.

[0004] To address the problem of insufficient sealing performance in the prior art, one objective of the present invention is to provide a dustproof assembly, comprising a first housing; a second housing coaxially disposed with the first housing, wherein the outer diameter of the second housing is smaller than the inner diameter of the first housing, the first housing or the second housing rotates about the central axis of the second housing, and a transition chamber is formed between the first housing and the second housing; and a dustproof member disposed within the transition chamber, the dustproof member being used to seal the spatial gap between the first housing and the second housing.

[0005] In a preferred embodiment of the dust-blocking assembly of the present invention, the dust-blocking component includes a blocking portion and a sealing portion, wherein the blocking portion is disposed on the outer peripheral surface of the second housing and the sealing portion is disposed on the inner peripheral surface of the first housing; or, the blocking portion is disposed on the inner peripheral surface of the first housing and the sealing portion is disposed on the outer peripheral surface of the second housing; the blocking portion and the sealing portion are clearance-fitted.

[0006] In a preferred embodiment of the dust-blocking assembly of the present invention, the cross-sectional area of ​​the first housing gradually decreases from a position away from the reference plane to a position closer to the reference plane, wherein the cross-section of the first housing is perpendicular to the central axis of the first housing, and the outer peripheral surface of the first housing is used to guide dust to slide downward in a directional manner.

[0007] In a preferred embodiment of the dust-blocking assembly of the present invention, the cross-sectional area of ​​the second housing gradually decreases from a position away from the reference plane to a position closer to the reference plane, wherein the cross-section of the second housing is perpendicular to the axis of the second housing.

[0008] In a preferred embodiment of the dust-blocking assembly of the present invention, the first housing and the second housing are arranged in parallel, and the angle between the extension line of the outer peripheral surface of the first housing and the axis of the first housing is 15°~30°.

[0009] As a preferred embodiment of the dust-blocking assembly of the present invention, the following is provided: n blocking parts are provided, where n is a positive integer ≥1, and the n blocking parts are equidistantly arranged along the axial direction of the first housing; m sealing parts are provided, where m is a positive integer ≥1, and the m sealing parts are arranged in a one-to-one correspondence with the n blocking parts.

[0010] In a preferred embodiment of the dust-blocking assembly of the present invention, there is an annular gap between each of the n blocking parts and the m sealing parts, and a brush is embedded in each of the annular gaps. The annular gaps are 3 mm wide and the brushes are 0.2 mm in diameter.

[0011] Another object of the present invention is to provide a dustproof grinding head, comprising: a housing; a dustproof assembly disposed within the housing, comprising a first housing and a second housing coaxially arranged, the first housing being fixedly connected to the housing; a driving member disposed within the housing, the output end of the driving member having a driving shaft, the driving shaft being connected to the second housing; and shaft end seals disposed at both ends of the driving shaft.

[0012] As a preferred embodiment of the dustproof grinding head of the present invention, it further includes: a turntable disposed at one end of the second housing near the reference surface, and the turntable being coaxially disposed with the second housing; and a dust cover disposed inside the second housing, the dust cover being used to cover the drive shaft.

[0013] As a preferred embodiment of the dustproof grinding head of the present invention, it further includes a housing brush, wherein the housing is in indirect contact with the reference surface, the housing brush is disposed at one end of the housing facing the reference surface, and the housing brush is used to seal the space between the housing and the reference surface.

[0014] The beneficial effects of the present invention are as follows: By coaxially arranging the first housing and the second housing to form a transition chamber, the dust-blocking component can accurately seal the space between the two housings, blocking dust intrusion from the source and greatly improving the effectiveness of sealing protection; the design of the transition chamber provides a buffer area for dust, preventing dust from directly impacting the core sealing structure and reducing the wear rate. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a cross-sectional view of the dust-blocking component of the present invention.

[0017] Figure 2 This is a partial cross-sectional view of the dust-blocking component of the present invention.

[0018] Figure 3 This is a cross-sectional view of the dust-blocking component of the present invention in use.

[0019] Figure 4 This is a schematic diagram showing the included angle of the dust-blocking component of the present invention.

[0020] Figure 5 This is a schematic diagram of the annular gap of the dust-blocking component of the present invention.

[0021] Figure 6 This is a view of the grinding side of the grinding head of the present invention.

[0022] Figure 7 This is a cross-sectional view of the grinding head of the present invention.

[0023] In the figure: 100, first housing; 200, second housing; 300, transition chamber; 400, dustproof component; 401, blocking part; 402, sealing part; 403, annular gap; 404, brush; L, spatial interval; C, included angle; 500, outer shell; 501, outer shell brush; 600, driving component; 601, driving shaft; 700, shaft end seal; 800, turntable; 900, dust cover. Detailed Implementation

[0024] To make the objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0027] Example 1, see Figure 1 This is the first embodiment of the present invention, which provides a dust-blocking component.

[0028] Specifically, the dust-blocking assembly includes a first housing 100, a second housing 200, and a dust-blocking component 400. The first housing 100 is an annular cylindrical structure made of aluminum alloy, providing good structural stability. The second housing 200 is also an annular structure, with its outer diameter smaller than the inner diameter of the first housing 100. The first housing 100 and the second housing 200 are coaxially nested, forming an annular transition chamber 300 between them. The width of the transition chamber 300 matches the dimensional difference between the two housings, providing buffering and blocking space for dust.

[0029] During operation, the installation method can be selected such that the first housing 100 is fixed and the second housing 200 rotates around its own central axis, or the second housing 200 is fixed and the first housing 100 rotates around the axis of the second housing 200, to adapt to the transmission requirements of the grinding head. In this embodiment, the method of fixing the first housing 100 and rotating the second housing 200 around its own axis is selected. Among them, the dustproof component 400 is installed in the transition chamber 300, and its size matches the space of the transition chamber 300. It can completely seal the space gap L between the first housing 100 and the second housing 200, preventing dust from directly penetrating through the space gap L, and achieving basic dust protection function.

[0030] Example 2, see Figures 1-5 This is the second embodiment of the present invention, and the structural details of the dust-blocking component will be described in detail one by one.

[0031] Specifically, the dustproof component 400 includes a blocking part 401 and a sealing part 402 that cooperate with each other. The blocking part 401 and the sealing part 402 can be installed in two optional ways. In the first installation method, the blocking part 401 is welded to the outer circumferential surface of the second housing 200, and the sealing part 402 is fixed to the inner circumferential surface of the first housing 100 with screws. In the second installation method, the blocking part 401 is fixed to the inner circumferential surface of the first housing 100, and the sealing part 402 is fixed to the outer circumferential surface of the second housing 200. The blocking part 401 and the sealing part 402 are fitted with a clearance, with the clearance value controlled between 0.1 and 0.3 mm. This misaligned fit between the blocking part 401 and the sealing part 402 forms a double protective barrier, further improving the sealing effect. At the same time, the clearance fit avoids frictional wear during relative movement, thus extending their service life.

[0032] Preferably, the cross-sectional area of ​​the first housing 100 gradually decreases from the position furthest from the reference surface (i.e., the surface to be sanded) towards the position closer to the reference surface, wherein the cross-section of the first housing 100 is perpendicular to the axis of the first housing 100. Here, the reference surface refers to the wall surface, board surface, etc., that comes into contact with the sandpaper during the sanding operation. This creates an inclined guiding surface on the outer periphery of the first housing 100. When dust comes into contact with the outer periphery of the first housing 100, it will slide downwards along the inclined surface under the action of gravity, preventing dust accumulation on the surface of the first housing 100 and reducing the risk of dust breaching the sealing structure.

[0033] Preferably, the cross-sectional area of ​​the second housing 200 gradually decreases from the position away from the reference plane to the position closer to the reference plane, and the cross-section of the second housing 200 is perpendicular to the axis of the second housing 200. The second housing 200 adopts the same gradually changing cross-sectional area design as the first housing 100, so that its outer peripheral surface also forms an inclined guiding structure, which works in conjunction with the guiding surface of the first housing 100 to form a dust guiding channel, further improving the dust sliding efficiency and reducing dust residue in the transition chamber 300.

[0034] Preferably, the first housing 100 and the second housing 200 are arranged in parallel to ensure that the width of the transition chamber 300 between the first housing 100 and the second housing 200 is uniform. The angle C between the extension line of the outer peripheral surface of the first housing 100 and the axis of the first housing 100 is set to 15°~30°, preferably 20°. This range of angle C has been experimentally verified to ensure that dust can slide smoothly under the action of gravity without reducing the structural strength of the housing due to an excessively large angle C, and to prevent dust from being trapped during the sliding process due to an excessively small angle C, thus achieving a balance between guiding effect and structural strength.

[0035] The experimental conditions in Table 1 below are as follows: room temperature 25℃, humidity 50%, dust is common calcium carbonate dust used for grinding building walls (particle size 0.1-100μm, average particle size 50μm, density 1.2g / cm³); dust sliding efficiency = (total amount of dust transported - amount of residual dust) / total amount of dust transported × 100%, transport rate 1g / min, experimental duration 30 minutes; shell compressive strength test standard: the pressure value when axial pressure is applied until the shell deforms by 0.1mm.

[0036] Table 1:

[0037] Serial Number Angle parameter ° Dust sliding efficiency % Surface residual dust (mg) shell compressive strength (MPa) 1 15 82.3 177.2 42.5 2 18 89.7 103.5 40.8 3 20 95.6 44.1 39.6 4 25 93.2 68.3 35.7 5 30 87.5 125.4 31.2

[0038] The dust sliding efficiency analysis is as follows:

[0039] When the included angle C is 15°, the dust sliding efficiency is only 82.3%, and the residual dust amount reaches 177.2mg. Because the included angle C is too small, the inclination of the shell surface is insufficient, and the downward force of the dust under the action of gravity is not enough. Some dust is easy to adhere to the shell surface and form accumulation, resulting in low sliding efficiency.

[0040] When the included angle C is 18°, the sliding efficiency increases to 89.7%, and the residual dust amount decreases to 103.5mg. The increased inclination angle enhances the downward force of the dust and reduces adhesion, but some fine dust particles still remain.

[0041] When the included angle C is 20°, the sliding efficiency reaches a peak of 95.6%, with only 44.1 mg of residual dust. At this included angle C, the inclination of the shell surface is moderate, and the component of gravity on the dust along the shell surface is sufficient to overcome the adhesion between the dust and the shell surface. Most of the dust can slide off quickly, with almost no obvious accumulation.

[0042] When the included angle C is 25°, the sliding efficiency drops slightly to 93.2%, and the residual dust increases to 68.3 mg. An excessively large included angle C causes the dust to slide down too quickly. Some dust bounces back after impacting the inner wall of the transition chamber 300 during the sliding process due to inertia, and a small amount of dust re-adheres to the shell surface, causing a slight decrease in sliding efficiency.

[0043] When the included angle C is 30°, the sliding efficiency further decreases to 87.5%, and the residual dust amount reaches 125.4 mg. An excessively large included angle C makes the shell surface tilt too steep, shortens the dust sliding path, and intensifies the rebound phenomenon. At the same time, some dust is prone to forming eddies and being retained at the bottom of the transition chamber 300, resulting in a significant decrease in sliding efficiency.

[0044] The compressive strength analysis of the shell is as follows:

[0045] When the included angle C is 15°, the shell's compressive strength is at its highest, reaching 42.5 MPa. The smaller the included angle C, the larger the radial cross-sectional dimension of the shell, resulting in more uniform stress distribution and stronger compressive resistance.

[0046] As the included angle C increases, the radial cross-sectional dimensions of the shell gradually decrease, and the compressive strength shows a decreasing trend: 40.8 MPa at 18°, 39.6 MPa at 20°, 35.7 MPa at 25°, and drops to 31.2 MPa at 30°.

[0047] When the included angle C is 20°, the shell compressive strength is 39.6MPa. Although it is lower than 15° and 18°, it can still meet the mechanical requirements of grinding operations. The conventional grinding head shell compressive strength requirement is ≥35MPa, and it will not deform or be damaged due to insufficient structural strength.

[0048] In summary, the experimental data fully demonstrate that 20° is the optimal angle C between the outer circumferential surface of the first shell 100 and the axis, which can ensure efficient dust sliding and maintain the stability of the shell structure, thus meeting the design requirements.

[0049] Furthermore, there are n blocking parts 401, where n is a positive integer ≥ 1. In this embodiment, n is preferably 3. The three blocking parts 401 are equidistant along the axial direction of the first housing 100, and the distance between two adjacent blocking parts 401 is 8~12mm. There are m sealing parts 402, where m is a positive integer ≥ 1, and m is also preferably 3. The three sealing parts 402 are arranged in a one-to-one correspondence with the three blocking parts 401, that is, each blocking part 401 corresponds to one sealing part 402, forming three independent protective units. The corresponding arrangement of multiple sets of blocking parts 401 and sealing parts 402 constructs a progressive sealing protection, which can sequentially block dust of different particle sizes, greatly improving the overall dustproof effect. At the same time, the equidistant arrangement ensures the uniformity of protection and avoids the occurrence of protection dead corners.

[0050] Furthermore, annular gaps 403 are formed between the three blocking parts 401 and the three sealing parts 402. The width of the annular gaps 403 is precisely controlled to 3mm. A brush 404 is tightly embedded in each annular gap 403. The single diameter of the brush 404 is 0.2mm and it is made of wear-resistant nylon. The annular gaps 403 provide a stable installation space for the brush 404. The 3mm gap width is compatible with the 0.2mm diameter brush 404, ensuring that the brush 404 is tightly arranged and the structure is stable after being embedded. The brush 404 has good elasticity and sealing properties, which can further fill the gap between the blocking part 401 and the sealing part 402. At the same time, it produces slight elastic deformation when the shell rotates relative to each other, which ensures the sealing effect without generating excessive frictional resistance and can block grinding dust.

[0051] Example 3, see Figures 1-7 This is the third embodiment of the present invention, which provides a dustproof grinding head.

[0052] Specifically, the dustproof grinding head includes a housing 500, the aforementioned dustproof assembly, a drive unit 600, and a shaft end seal 700. The housing 500 is a hollow cylindrical structure made of engineering plastic, combining lightweight design with protective performance. The dustproof assembly is installed entirely inside the housing 500, with the first housing 100 fixedly connected to the inner wall of the housing 500 by screws to ensure a stable installation. The drive unit 600 is a servo motor, fixed inside the housing 500 at the end furthest from the reference surface. The output end of the drive unit 600 has a drive shaft 601, which is fixedly connected to the second housing 200 via a key, providing power for the rotation of the second housing 200. The shaft end seal 700 is a rubber sealing ring, respectively located at both ends of the drive shaft 601, and fitted onto the outer circumferential surface of the drive shaft 601. The outer casing 500 provides overall protection for the internal components. The connection between the dustproof component and the drive component 600 ensures stable power transmission. The shaft end seal 700 can prevent dust from entering from the end of the drive shaft 601, forming an end protection barrier, and works with the dustproof component to prevent dust.

[0053] Preferably, the dustproof grinding head also includes a turntable 800 and a dust cover 900. The turntable 800 is a circular plate structure made of aluminum alloy, located at one end of the second housing 200 near the reference surface, and is fixedly connected to the second housing 200 by bolts. The turntable 800 is coaxially arranged with the second housing 200, and its end face is used to attach sandpaper. The dust cover 900 is an annular cover made of leather with built-in elastic steel wire, located inside the second housing 200, completely covering the outer circumference of the drive shaft 601. The turntable 800 provides a mounting carrier for the sandpaper, ensuring effective grinding operations. The dust cover 900 utilizes the smooth surface and dust-resistant properties of leather, along with the good deformation capacity of the elastic steel wire, to effectively prevent dust from contacting the drive shaft 601. It can also withstand slight vibrations and repeated compression during equipment operation, extending its service life and further enhancing the protection of the drive shaft 601.

[0054] Furthermore, the dustproof grinding head also includes a housing brush 501. The housing brush 501 is made of soft nylon material, 7mm thick, with a bristle diameter of 0.1mm. It is installed on the end of the housing 500 facing the reference surface by adhesive and screws, surrounding the end face of the housing 500. The housing 500 indirectly contacts the reference surface through the housing brush 501, avoiding direct friction between the housing 500 and the reference surface that could cause scratches. Simultaneously, the housing brush 501 seals the gap between the housing 500 and the reference surface, forming an outer seal to prevent dust from entering from the contact point between the grinding head and the reference surface. Working in conjunction with the inner seal of the dustproof assembly, it further enhances the overall dustproof effect.

[0055] To facilitate understanding of the technical solution of this invention, its working principle is explained in detail below:

[0056] When the dustproof grinding head is working, the drive unit 600 starts and drives the second housing 200 and the turntable 800 to rotate synchronously through the drive shaft 601. The sandpaper on the turntable 800 contacts the reference surface to perform grinding operations. At this time, the outer shell brush 501 at the end of the outer shell 500 is in contact with the reference surface to form the first sealing barrier, blocking most of the dust from entering the interior of the outer shell 500. A small amount of dust that breaks through the outer seal enters the transition chamber 300 and is blocked layer by layer by the brush 404 between the three sets of blocking parts 401 and the sealing part 402 in the dustproof assembly, forming a progressive protection. At the same time, the gradient cross-sectional area design of the first housing 100 and the second housing 200 causes the dust attached to the surface of the housing to slide downward under the action of gravity, avoiding accumulation. The shaft end seal 700 and the dust cover 900 provide protection from the end and outer peripheral surface of the drive shaft 601, respectively, to prevent dust from intruding into the transmission core area. Throughout the process, the various dustproof structures work together to form a multi-layered dustproof system, effectively preventing dust from entering rotating parts, solving the problem of the grinding head getting stuck due to dust, and ensuring operational stability and grinding quality.

[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dust deflector assembly characterized by: The dust blocking assembly comprises a first shell (100), a second shell (200) coaxially arranged with the first shell (100), the outer diameter of the second shell (200) being smaller than the inner diameter of the first shell (100), the first shell (100) or the second shell (200) rotating around the central axis of the second shell (200), and a transition chamber (300) being formed between the first shell (100) and the second shell (200). A dust blocking piece (400) is arranged in the transition chamber (300), and the dust blocking piece (400) is used for blocking the space interval (L) between the first shell (100) and the second shell (200). The dust blocking piece (400) comprises a blocking part (401) and a sealing part (402), the blocking part (401) is arranged on the outer circumferential surface of the second shell (200), and the sealing part (402) is arranged on the inner circumferential surface of the first shell (100). Alternatively, the blocking part (401) is arranged on the inner circumferential surface of the first shell (100), and the sealing part (402) is arranged on the outer circumferential surface of the second shell (200). The blocking part (401) and the sealing part (402) are in clearance fit. The cross-sectional area of the first shell (100) gradually decreases from the position away from the reference surface to the position close to the reference surface, the cross section of the first shell (100) is perpendicular to the central axis of the first shell (100), and the outer circumferential surface of the first shell (100) is used for guiding the dust to slide downward. The cross-sectional area of the second shell (200) gradually decreases from the position away from the reference surface to the position close to the reference surface, the cross section of the second shell (200) is perpendicular to the central axis of the second shell (200). The first shell (100) and the second shell (200) are arranged in parallel, and the included angle (C) between the extension line of the outer circumferential surface of the first shell (100) and the central axis of the first shell (100) is 15°-30°. The blocking part (401) is provided with n, n is a positive integer greater than or equal to 1, and the n blocking parts (401) are equidistantly arranged along the axial direction of the first shell (100). The sealing part (402) is provided with m, m is a positive integer greater than or equal to 1, and the m sealing parts (402) are arranged one by one corresponding to the n blocking parts (401). There are annular gaps (403) between the n blocking parts (401) and the m sealing parts (402), and each annular gap (403) is embedded with a brush (404). The annular gap (403) is 3mm wide, and the diameter of the brush (404) is 0.2mm. The dust blocking assembly comprises a first shell (100), a second shell (200) coaxially arranged with the first shell (100), the outer diameter of the second shell (200) being smaller than the inner diameter of the first shell (100), the first shell (100) or the second shell (200) rotating around the central axis of the second shell (200), and a transition chamber (300) being formed between the first shell (100) and the second shell (200).

2. The dust shield assembly of claim 1, wherein: A dust blocking piece (400) is arranged in the transition chamber (300), and the dust blocking piece (400) is used for blocking the space interval (L) between the first shell (100) and the second shell (200).

3. A dust-free polishing head characterized by: The dust blocking piece (400) comprises a blocking part (401) and a sealing part (402), the blocking part (401) is arranged on the outer circumferential surface of the second shell (200), and the sealing part (402) is arranged on the inner circumferential surface of the first shell (100). Alternatively, the blocking part (401) is arranged on the inner circumferential surface of the first shell (100), and the sealing part (402) is arranged on the outer circumferential surface of the second shell (200). The blocking part (401) and the sealing part (402) are in clearance fit. The cross-sectional area of the first shell (100) gradually decreases from the position away from the reference surface to the position close to the reference surface, the cross section of the first shell (100) is perpendicular to the central axis of the first shell (100), and the outer circumferential surface of the first shell (100) is used for guiding the dust to slide downward. The cross-sectional area of the second shell (200) gradually decreases from the position away from the reference surface to the position close to the reference surface, the cross section of the second shell (200) is perpendicular to the central axis of the second shell (200). The first shell (100) and the second shell (200) are arranged in parallel, and the included angle (C) between the extension line of the outer circumferential surface of the first shell (100) and the central axis of the first shell (100) is 15°-30°. The blocking part (401) is provided with n, n is a positive integer greater than or equal to 1, and the n blocking parts (401) are equidistantly arranged along the axial direction of the first shell (100). The sealing part (402) is provided with m, m is a positive integer greater than or equal to 1, and the m sealing parts (402) are arranged one by one corresponding to the n blocking parts (401). There are annular gaps (403) between the n blocking parts (401) and the m sealing parts (402), and each annular gap (403) is embedded with a brush (404). The annular gap (403) is 3mm wide, and the diameter of the brush (404) is 0.2mm. The dust blocking assembly comprises a first shell (100), a second shell (200) coaxially arranged with the first shell (100), the outer diameter of the second shell (200) being smaller than the inner diameter of the first shell (100), the first shell (100) or the second shell (200) rotating around the central axis of the second shell (200), and a transition chamber (300) being formed between the first shell (100) and the second shell (200). A driving member (600) is arranged in the outer shell (500), and an output end of the driving member (600) is provided with a driving shaft (601), and the driving shaft (601) is connected with the second shell (200). A shaft end sealing member (700) is arranged at both ends of the driving shaft (601).

4. The dust-free polishing head of claim 3, wherein: Further comprising, A rotating disc (800) is arranged at one end of the second shell (200) close to the reference surface, and the rotating disc (800) is coaxially arranged with the second shell (200). A dust cover (900) is arranged in the second shell (200), and the dust cover (900) is used for covering the driving shaft (601).

5. A dust-free polishing head as claimed in claim 3 or 4, characterized in that: Further comprising an outer shell brush (501), the outer shell (500) is indirectly contacted with the reference surface, the outer shell brush (501) is arranged at one end of the outer shell (500) facing the reference surface, and the outer shell brush (501) is used for sealing the space between the outer shell (500) and the reference surface.

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