Finishing spindle structure and machine tool

Abstract

The invention relates to a finishing spindle structure and a machine tool. The finishing spindle structure comprises a supporting body, a shaft outer sleeve, a spindle cooling sleeve and a finishing spindle. The shaft outer sleeve comprises a first radial part and a first axial part, the shaft outer sleeve is located on the outer side of the mounting hole of the supporting body, and the first radial part is fixedly connected to the supporting body; the main shaft cooling sleeve comprises a second radial part and a second axial part, the second radial part is fixedly connected to the first radial part, a liquid cooling groove is formed in the outer wall of the second axial part, and a liquid cooling sleeve is formed between the liquid cooling groove and the inner wall of the shaft outer sleeve; a bearing is arranged between the inner wall of the spindle cooling sleeve and the outer wall of the finishing spindle, a front bearing gland is arranged at the front end of the spindle outer sleeve and the front end of the spindle cooling sleeve, and an end cover is fixed to the front end of the finishing spindle and covers the front bearing gland and the first axial portion of the spindle outer sleeve. The finishing spindle structure can improve the rotating precision and stability of the finishing spindle, so that the finishing quality and the finishing efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of machine tools, and in particular to a dressing spindle structure of a machine tool for dressing a grinding wheel. The present invention also relates to a machine tool provided with the dressing spindle structure. Background Art

[0002] In the field of grinding, the condition of the grinding wheel has a crucial impact on the processing quality. As the grinding process progresses, the grinding wheel will continue to wear out during use. The edges and corners will gradually become rounded and blunt over time, and the profile will also change. This cannot guarantee the shape accuracy and surface roughness required for processing. Therefore, it is necessary to promptly and correctly dress the grinding wheel to restore the shape accuracy of the grinding wheel and the sharpness of the abrasive grains. This is an indispensable part of improving grinding efficiency and ensuring grinding quality.

[0003] The dressing process for grinding wheels is primarily accomplished using a dressing spindle mounted on the grinding machine's dressing device. Dressing is performed by contacting a diamond roller on the spindle with the grinding wheel. During dressing, the diamond roller moves along the grinding wheel surface at a specific rotational and feed speed. The diamond roller, with its high hardness and sharp cutting edge, moves in contact with the grinding wheel, making the wheel's profile as close to a true circle as possible while removing any debris and defects from the wheel's surface.

[0004] It can be seen that the accuracy of the dressing spindle has a very large impact on the dressing quality and dressing efficiency of the grinding wheel. Therefore, further improving the rotation accuracy and stability of the dressing spindle to improve the dressing quality and dressing efficiency is a technical problem that needs to be further solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a dressing spindle structure to solve the above technical problems.

[0006] Another object of the present invention is to provide a machine tool provided with the dressing spindle structure.

[0007] To achieve the above-mentioned objectives, the present invention provides a dressing spindle structure, comprising a support body, a shaft sleeve, a spindle cooling sleeve and a dressing spindle; the shaft sleeve comprises a first radial portion and a first axial portion, the shaft sleeve is located outside the mounting hole of the support body, and the first radial portion is fixedly connected to the support body; the spindle cooling sleeve comprises a second radial portion and a second axial portion, the second radial portion is fixedly connected to the first radial portion, and the outer wall of the second axial portion is provided with a liquid cooling groove, and a liquid cooling sleeve is formed between the liquid cooling groove and the inner wall of the shaft sleeve; a bearing is provided between the inner wall of the spindle cooling sleeve and the outer wall of the dressing spindle, and a front bearing pressure cover is provided at the front end of the shaft sleeve and the spindle cooling sleeve, and an end cover is fixed to the front end of the dressing spindle, and the end cover covers the front bearing pressure cover and the first axial portion of the shaft sleeve.

[0008] Optionally, a front bearing is provided between the inner wall of the spindle cooling jacket and the outer wall of the stepped shaft.

[0009] Optionally, a rear bearing is provided between the inner wall of the spindle cooling jacket and the outer wall of the stepped shaft, and the rear bearing is spaced apart from the front bearing and is located on the rear side of the front bearing.

[0010] Optionally, the dressing spindle includes a first stepped shaft, a second stepped shaft and a third stepped shaft distributed from the rear end to the front end, and the diameters of the first stepped shaft, the second stepped shaft and the third stepped shaft increase successively; the inner wall of the spindle cooling sleeve is a stepped hole, including a first stepped hole, a second stepped hole and a third stepped hole distributed from the rear end to the front end; a rear bearing is provided between the first stepped shaft and the first stepped hole, and a front bearing is provided between the third stepped shaft and the third stepped hole.

[0011] Optionally, the second stepped shaft is provided with an external thread that cooperates with a locking nut, and the locking nut presses the front bearing in a direction from rear to front.

[0012] Optionally, two front bearings and one rear bearing are arranged side by side, and the inner diameter of the front bearing is larger than the inner diameter of the rear bearing.

[0013] Optionally, a flange portion extending radially inward is provided between the first stepped hole and the second stepped hole of the spindle cooling sleeve, and the front end of the rear bearing abuts against the flange portion.

[0014] Optionally, the second radial portion of the spindle cooling jacket is connected to a pressure ring at the rear end surface for fixing the rear bearing.

[0015] Optionally, the trimming spindle includes a fourth stepped shaft, a first sealing structure is formed between the front bearing cover and the fourth stepped shaft, and a second sealing structure is formed between the end cover and the front bearing cover.

[0016] Optionally, the first sealing structure comprises a plurality of first annular steps arranged on the fourth stepped shaft and a plurality of second annular steps arranged on the front bearing gland, the diameters of the plurality of first annular steps gradually increase from the rear end to the front end, the diameters of the plurality of second annular steps gradually decrease from the rear end to the front end, and the first annular steps and the second annular steps form stepped gaps therebetween.

[0017] Optionally, the front bearing gland is provided with an inner edge step, and the front end of the front bearing abuts against both the rear end face of the fourth stepped shaft and the inner edge step.

[0018] Optionally, the second sealing structure comprises a sealing groove arranged on the front side of the front bearing gland and a sealing part arranged on the end cover, the sealing groove is adjacent to the second annular step, and the sealing part is embedded in the sealing groove to form a labyrinth sealing structure.

[0019] Optionally, the sealing groove comprises an opening and an inner expansion groove, one side of the inner expansion groove adjacent to the second annular step is a straight wall, and the other side of the inner expansion groove away from the second annular step is an inclined wall, and the width of the inner expansion groove gradually increases from the opening to the bottom.

[0020] Optionally, the sealing part of the end cover comprises an axial sealing part and a radial sealing part, the axial sealing part extends to the rear end along the straight wall of the inner expansion groove, and the radial sealing part extends from the rear end of the axial sealing part to the inclined wall of the inner expansion groove.

[0021] Optionally, the finishing spindle comprises a fifth stepped shaft, the diameter of the fifth stepped shaft is smaller than that of the fourth stepped shaft, and the end cover is sleeved on the fifth stepped shaft through the axial hole and is fixed to the front end face of the fourth stepped shaft.

[0022] Optionally, a gas sealing ring is arranged between the first axial part of the shaft sleeve and the inner wall of the end cover, a first gas sealing groove is arranged between the inner wall of the gas sealing ring and the first axial part, and a second gas sealing groove is arranged between the outer wall of the gas sealing ring and the inner wall of the end cover.

[0023] To achieve the above-mentioned another object, the present application provides a machine tool, which comprises a workpiece box body and a finishing device arranged on the workpiece box body, the finishing device is installed on one side of the workpiece box body, and the finishing device has the finishing spindle structure of any one of the above-mentioned embodiments, and the finishing spindle of the finishing device is perpendicular to the workpiece shaft of the workpiece box body.

[0024] The dressing spindle structure provided by the present invention is mainly composed of components such as a support body, a shaft outer sleeve, a spindle cooling sleeve and a dressing spindle. Its structure is compact and reasonable, and can be assembled in sequence in a nested manner. It is not only easy to assemble, disassemble and maintain, but also, after the assembly is completed, there is a bearing between the spindle cooling sleeve and the dressing spindle, and a liquid cooling sleeve is formed between the spindle cooling sleeve and the shaft outer sleeve. At the same time, the shaft outer sleeve, the spindle cooling sleeve, the front bearing pressure cover and the dressing spindle are sealed as a whole through the end cover, which can significantly improve the rotation accuracy and stability of the dressing spindle, and has a higher level of accuracy in terms of roundness and concentricity, thereby ensuring the grinding quality and laying the foundation for subsequent high-precision grinding processing, especially for workpieces with precision requirements, which can enable the workpiece to meet the ideal precision requirements.

[0025] The machine tool provided by the present invention is provided with the dressing spindle structure. Since the dressing spindle structure has the above-mentioned technical effects, the machine tool provided with the dressing spindle structure should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A partial cross-sectional view of a trimming spindle structure provided by an embodiment of the present invention;

[0027] Figure 2 for Figure 1 A partial enlarged view of

[0028] Figure 3 for Figure 2 A partial enlarged view of the front bearing cover and the fourth step shaft, and the end cover and the front bearing cover matching each other;

[0029] Figure 4 This is a partial enlarged view of a gas sealing ring provided between the first axial portion of the shaft outer sleeve and the inner wall of the end cover;

[0030] Figure 5 A schematic diagram of the structure of a machine tool provided by an embodiment of the present invention when in a machining state;

[0031] Figure 6 This is a structural schematic diagram of a machine tool provided by an embodiment of the present invention when it is in a dressing state.

[0032] In the picture:

[0033] 1. Front bearing; 2. Lock nut; 3. Rear bearing; 4. Pressure ring; 7. Airtight seal ring; 71. First airtight seal groove; 72. Second airtight seal groove; 10. Support body; 20. Shaft sleeve; 21. First radial portion; 22. First axial portion; 23. Flange; 30. Spindle cooling jacket; 31. Second radial portion; 32. Second axial portion; 321. Liquid cooling tank; 301. First stepped hole; 302. Second stepped hole; 303. Third stepped hole; 304. Flange; 40. Dressing spindle; 41. First stepped shaft; 42. Second stepped shaft; 43. Third stepped shaft; 44. Fourth stepped shaft; 4 41. First annular step; 45. Fifth stepped shaft; 50. Front bearing cover; 51. Second annular step; 52. Inner edge step; 53. Sealing groove; 531. Opening; 532. Inner expansion groove; 60. End cover; 61. Sealing part; 611. Axial sealing part; 612. Radial sealing part; 70. Diamond roller; 81. Synchronous belt; 82. Synchronous wheel; 90. Motor; 101. First bolt; 102. Second bolt; 103. Third bolt; 104. Fourth bolt; 200. Workpiece yaw shaft; 300. Workpiece housing; 400. Dressing device; 500. Grinding wheel; 600. Workpiece. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] In this article, terms such as "upper, lower, inside, outside" are established based on the positional relationships shown in the drawings. Depending on the different drawings, the corresponding positional relationships may also change accordingly. Therefore, they cannot be understood as absolute limitations on the scope of protection; moreover, relational terms such as "first" and "second" are only used to distinguish one component from another with the same name, and do not necessarily require or imply any actual relationship or order between these components.

[0036] Please refer to Figure 1 、 Figure 2 , Figure 1 A partial cross-sectional view of a trimming spindle structure provided by an embodiment of the present invention; Figure 2 for Figure 1 A partial enlarged view of .

[0037] As shown in the figure, in a specific embodiment, the dressing spindle structure provided by the present invention is mainly assembled from components such as a support body 10, a shaft outer sleeve 20, a spindle cooling sleeve 30, a dressing spindle 40, a front bearing cover 50, and an end cover 60.

[0038] The support body 10 is a rectangular plate structure with a mounting hole for mounting the dressing spindle 40 . The dressing spindle 40 is mounted in the mounting hole through the shaft sleeve 20 , the spindle cooling sleeve 30 , the front bearing cover 50 , and the end cover 60 .

[0039] A diamond roller 70 is fixed to the front end of the dressing spindle 40, and a synchronous wheel 82 is fixed to the rear end. The motor 90 for driving the dressing spindle 40 is installed on the other side of the support body 10, and its power output end is connected to the synchronous wheel 82 through a synchronous belt 81, that is, the motor 90 drives the dressing spindle 40 and the diamond roller 70 to rotate at high speed through the synchronous belt 81 and the synchronous wheel 82 to dress the grinding wheel.

[0040] The shaft sleeve 20 is located outside the mounting hole of the support body 10, and has a first radial portion 21 and a first axial portion 22. The support body 10 is designed with multiple bolt holes around the mounting hole. A flange 23 is provided on the inner side of the first radial portion 21, and is embedded in the mounting hole of the support body 10 through the flange 23 for easy positioning. The outer edge of the first radial portion 21 is fixedly connected to the support body 10 by a first bolt 101.

[0041] The spindle cooling sleeve 30 has a second radial portion 31 and a second axial portion 32, wherein the second radial portion 31 is located in the mounting hole of the support body 10 and is fixedly connected to the flange 23 of the first radial portion 21 corresponding to the mounting hole by a second bolt 102, and the second bolt 102 is in the opposite direction to the first bolt 101. The outer wall of the second axial portion 32 is provided with a liquid cooling groove 321, and a liquid cooling sleeve is formed between the liquid cooling groove 321 and the inner wall of the shaft sleeve 20; a front bearing 1 and a rear bearing 3 are provided between the inner wall of the spindle cooling sleeve 3 and the outer wall of the dressing spindle 40, and a front bearing pressure cover 50 is provided at the front end of the shaft sleeve 20 and the spindle cooling sleeve 30, and an end cover 60 is fixed to the front end of the dressing spindle 40, and the end cover 60 covers the front bearing pressure cover 50 and the first axial portion 22 of the shaft sleeve 20 at the same time.

[0042] Specifically, the trimming spindle 40 is a stepped shaft, which includes, from the rear end to the front end, a first stepped shaft 41, a second stepped shaft 42, a third stepped shaft 43, a fourth stepped shaft 44 and a fifth stepped shaft 45, wherein the diameters of the first stepped shaft 41, the second stepped shaft 42, the third stepped shaft 43 and the fourth stepped shaft 44 increase successively, and the diameter of the fifth stepped shaft 45 is smaller than that of the fourth stepped shaft 44.

[0043] The inner wall of the spindle cooling sleeve 30 is a stepped hole, which includes a first stepped hole 301, a second stepped hole 302 and a third stepped hole 303 from the rear end to the front end. A rear bearing 3 is provided between the first stepped shaft 41 and the first stepped hole 301, and two front bearings 1 are provided side by side between the third stepped shaft 43 and the third stepped hole 303. Moreover, the inner diameter of the front bearing 1 is larger than the inner diameter of the rear bearing 3.

[0044] The front end of the front bearing 1 abuts against the rear end face of the fourth stepped shaft 44, the end cover 60 is mounted on the fifth stepped shaft 45 through its axial hole, and is fixed to the front end face of the fourth stepped shaft 44 by a third bolt 103, and the direction of the third bolt 103 is the same as that of the first bolt 101.

[0045] The second stepped shaft 42 is provided with an external thread that cooperates with the locking nut 2. The locking nut 2 presses the inner ring of the front bearing 1 in the direction from back to front. A flange portion 304 extending radially inward is provided between the first stepped hole 301 and the second stepped hole 302 of the spindle cooling sleeve 30. The front end of the inner ring of the rear bearing 3 abuts against the flange portion 304. The second radial portion 31 of the spindle cooling sleeve 30 is connected to the pressure ring 4 through the fourth bolt 104 at the rear end face to fix the rear bearing 3 through the pressure ring 4. The direction of the fourth bolt 104 is the same as that of the second bolt 102.

[0046] Please refer to Figure 3 , Figure 3 for Figure 2 The figure shows a partial enlarged view of the front bearing cover and the fourth step shaft, and the end cover and the front bearing cover.

[0047] As shown in the figure, in order to better seal, a first sealing structure is formed between the front bearing cover 50 and the fourth stepped shaft 44 , and a second sealing structure is formed between the end cover 60 and the front bearing cover 50 .

[0048] In this embodiment, the fourth-step shaft 44 is provided with multiple first annular steps 441, and the diameters of the multiple first annular steps 441 gradually increase from the rear end to the front end. The front bearing cover 50 is provided with multiple corresponding second annular steps 51, and the diameters of the multiple second annular steps 51 gradually decrease from the rear end to the front end, forming a step-shaped gap between the first annular step 441 and the second annular step 51.

[0049] The front bearing cover 50 is provided with an inner edge step 52 , and the front end of the front bearing 1 abuts against the rear end surface of the fourth stepped shaft 44 and the inner edge step 52 at the same time, wherein the outer ring of the front bearing 1 abuts against the inner edge step 52 .

[0050] A sealing groove 53 adjacent to the second annular step 51 is provided on the front side of the front bearing cover 50 , and a sealing portion 61 embedded in the sealing groove 53 is provided on the end cover 60 .

[0051] In this embodiment, the sealing groove 53 includes an opening 531 and an inner expansion groove 532. The side of the inner expansion groove 532 adjacent to the second annular step 51 is a straight wall, and the side of the inner expansion groove 532 away from the second annular step 51 is an inclined wall, and its width gradually increases from the opening to the bottom. The sealing portion 61 of the end cover 60 has an axial sealing portion 611 and a radial sealing portion 612. The axial sealing portion 611 extends toward the rear end along the straight wall of the inner expansion groove 532, and its thickness gradually decreases. The radial sealing portion 612 extends from the rear end of the axial sealing portion 611 to the inclined wall side of the inner expansion groove 532, thereby forming a labyrinth sealing structure.

[0052] Please refer to Figure 4 , Figure 4 This is a partial enlarged view of the air-sealing ring provided between the first axial portion of the shaft sleeve and the inner wall of the end cover.

[0053] As shown in the figure, an airtight ring 7 is provided between the first axial portion 22 of the shaft sleeve 20 and the inner wall of the end cover 60, a first airtight groove 71 is provided between the inner wall of the airtight ring 7 and the first axial portion 22, and a second airtight groove 72 is provided between the outer wall of the airtight ring 7 and the inner wall of the end cover 60.

[0054] By inputting compressed air into the first airtight sealing groove 71 and the second airtight sealing groove 72 , a pressure difference can be established with the outside, thereby forming an airtight seal in the circumferential direction.

[0055] The above embodiment is merely a preferred embodiment of the present invention and is not intended to be limiting. Based on this, targeted adjustments can be made according to actual needs to achieve different implementations. For example, other methods can be used to position the front bearing 1 and the rear bearing 3, etc. Due to the numerous possible implementation methods, we will not illustrate each one here.

[0056] The dressing spindle structure has a front bearing 1 and a rear bearing 3 between the spindle cooling sleeve 30 and the dressing spindle 40, and a liquid cooling sleeve is formed between the spindle cooling sleeve 30 and the shaft outer sleeve 20. At the same time, the shaft outer sleeve 20, the spindle cooling sleeve 30, the front bearing pressure cover 50 and the dressing spindle 40 are sealed as a whole through the end cover 60, and a multi-step sealing structure is formed between the front bearing pressure cover 50 and the dressing spindle 40, a labyrinth sealing structure is formed between the end cover 60 and the front bearing pressure cover 50, and an air curtain sealing structure is formed between the air sealing ring 7 and the end cover 60 and the shaft outer sleeve 20.

[0057] By designing the above structure, the rotation accuracy and stability of the dressing spindle can be significantly improved, and a higher level of accuracy can be achieved in terms of roundness and concentricity, thereby ensuring the grinding quality. In addition, the structure is compact and reasonable, which is conducive to spatial layout and installation on the workpiece box of the machine tool. It is easy to assemble, disassemble and maintain during use.

[0058] Please refer to Figure 5、 Figure 6 , Figure 5 The structure schematic diagram of the machine tool in the machining state provided by the embodiment of the present application is shown in the figure; Figure 6 The structure schematic diagram of the machine tool in the dressing state provided by the embodiment of the present application is shown in the figure.

[0059] As shown in the figure, in addition to the above-mentioned dressing spindle structure, the present application also provides a machine tool, which is provided with a workpiece deflection shaft 200 and a workpiece box 300, one side of the workpiece box 300 is provided with a dressing device 400, the dressing device 400 has the dressing spindle structure described above, and the dressing spindle 40 thereof is perpendicular to the workpiece shaft of the workpiece box 300. When the workpiece 600 is machined, the workpiece box 300 will be deflected by a certain angle, and when the grinding wheel 500 is dressed, the workpiece box 300 will be deflected to the +90° position, so that the diamond roller 70 is in a position capable of dressing the grinding wheel 500.

[0060] When the grinding wheel 500 needs to be dressed, the grinding wheel 500 and the dressing spindle 40 are respectively moved from the machining area to the dressing position. Since the dressing spindle 40 is located on one side of the workpiece box 300, the dressing spindle 40 can be close to the workpiece, the grinding wheel, that is, close to the machining area, or in other words, the dressing position is close to the part machining point, so that the running distance of the X-axis and the Z-axis of the machine tool is shortened, the shape of the grinding wheel after dressing is more in line with the actual needs of machining, the error is reduced, and the dressing device 400 is integrally mounted on the workpiece box 300, which is convenient for quick response to dressing, thereby improving the machining efficiency.

[0061] The dressing spindle structure and the machine tool provided by the present application are described in detail above. In this paper, specific examples are applied to describe the principles and implementation modes of the present application, and the above description of the embodiments is only used to help understand the core idea of the present application. It should be pointed out that for ordinary skilled persons in the technical field, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A dressing spindle structure, characterized in that: It includes a support body, a shaft sleeve, a spindle cooling sleeve and a dressing spindle; the shaft sleeve includes a first radial portion and a first axial portion, the shaft sleeve is located outside the mounting hole of the support body, and the first radial portion is fixedly connected to the support body; the spindle cooling sleeve includes a second radial portion and a second axial portion, the second radial portion is fixedly connected to the first radial portion, and the outer wall of the second axial portion is provided with a liquid cooling groove, and a liquid cooling sleeve is formed between the liquid cooling groove and the inner wall of the shaft sleeve; a bearing is provided between the inner wall of the spindle cooling sleeve and the outer wall of the dressing spindle, and a front bearing cover is provided at the front end of the shaft sleeve and the spindle cooling sleeve, and an end cover is fixed to the front end of the dressing spindle, and the end cover covers the front bearing cover and the first axial portion of the shaft sleeve.

2. The dressing spindle structure according to claim 1, characterized in that: The dressing spindle is a stepped shaft, and a front bearing is provided between the inner wall of the spindle cooling sleeve and the outer wall of the stepped shaft.

3. The dressing spindle structure according to claim 2, characterized in that: A rear bearing is provided between the inner wall of the spindle cooling jacket and the outer wall of the stepped shaft. The rear bearing is spaced apart from the front bearing and is located at the rear side of the front bearing.

4. The dressing spindle structure according to claim 3, characterized in that: The dressing spindle includes a first stepped shaft, a second stepped shaft and a third stepped shaft distributed from the rear end to the front end, and the diameters of the first stepped shaft, the second stepped shaft and the third stepped shaft increase successively; the inner wall of the spindle cooling sleeve is a stepped hole, including a first stepped hole, a second stepped hole and a third stepped hole distributed from the rear end to the front end; a rear bearing is provided between the first stepped shaft and the first stepped hole, and a front bearing is provided between the third stepped shaft and the third stepped hole.

5. The dressing spindle structure according to claim 4, characterized in that: The second stepped shaft is provided with an external thread matched with a locking nut, and the locking nut presses the front bearing in a direction from rear to front.

6. The dressing spindle structure according to claim 5, characterized in that: Two front bearings and one rear bearing are arranged side by side, and the inner diameter of the front bearing is larger than the inner diameter of the rear bearing.

7. The dressing spindle structure according to claim 4, characterized in that: A flange portion extending radially inward is provided between the first stepped hole and the second stepped hole of the spindle cooling sleeve, and the front end of the rear bearing abuts against the flange portion.

8. The dressing spindle structure according to claim 7, characterized in that: The second radial portion of the spindle cooling jacket is connected to a pressure ring at the rear end surface for fixing the rear bearing.

9. The dressing spindle structure according to claim 2, characterized in that: The trimming spindle includes a fourth stepped shaft, a first sealing structure is formed between the front bearing cover and the fourth stepped shaft, and a second sealing structure is formed between the end cover and the front bearing cover.

10. The dressing spindle structure according to claim 9, characterized in that: The first sealing structure includes multiple first annular steps arranged on the fourth step shaft and multiple corresponding second annular steps arranged on the front bearing cover. The diameters of the multiple first annular steps gradually increase from the rear end to the front end, and the diameters of the multiple second annular steps gradually decrease from the rear end to the front end. A step-shaped gap is formed between the first annular step and the second annular step.

11. The dressing spindle structure according to claim 10, characterized in that: The front bearing cover is provided with an inner edge step, and the front end of the front bearing abuts against the rear end surface of the fourth stepped shaft and the inner edge step at the same time.

12. The dressing spindle structure according to claim 10, characterized in that: The second sealing structure includes a sealing groove provided on the front side of the front bearing cover and a sealing portion provided on the end cover, the sealing groove is adjacent to the second annular step, and the sealing portion is embedded in the sealing groove to form a labyrinth sealing structure.

13. The dressing spindle structure according to claim 12, characterized in that: The sealing groove includes an opening and an inner expansion groove. The side of the inner expansion groove adjacent to the second annular step is a straight wall, and the side of the inner expansion groove away from the second annular step is an inclined wall. Its width gradually increases from the opening to the bottom.

14. The dressing spindle structure according to claim 13, characterized in that: The sealing portion of the end cover includes an axial sealing portion and a radial sealing portion. The axial sealing portion extends toward the rear end along the straight wall of the inner expanded groove, and the radial sealing portion extends from the rear end of the axial sealing portion toward the inclined wall of the inner expanded groove.

15. The dressing spindle structure according to claim 9, characterized in that: The trimming spindle includes a fifth stepped shaft, the diameter of the fifth stepped shaft is smaller than that of the fourth stepped shaft, and the end cover is sleeved on the fifth stepped shaft through its shaft hole and fixedly connected to the front end surface of the fourth stepped shaft.

16. The dressing spindle structure according to any one of claims 1 to 15, characterized in that: An airtight ring is provided between the first axial portion of the shaft sleeve and the inner wall of the end cover, a first airtight groove is provided between the inner wall of the airtight ring and the first axial portion, and a second airtight groove is provided between the outer wall of the airtight ring and the inner wall of the end cover.

17. A machine tool, characterized in that: It includes a workpiece box and a dressing device arranged on the workpiece box, the dressing device is installed on one side of the workpiece box, and the dressing device has a dressing spindle structure according to any one of claims 1 to 16, and its dressing spindle is perpendicular to the workpiece axis of the workpiece box.

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