A rotary sealing structure and pneumatic chuck mechanism

Abstract

The present invention relates to the technical field of mechanical processing equipment, and discloses a rotary sealing structure, including a transmission component and a sealing component, wherein the transmission component includes a main shaft, a bearing sleeved on the main shaft, and a bearing seat, the main shaft can be connected to a pneumatic chuck, and the main shaft is provided with a first passage and a second passage, one end of which can be respectively connected to the pneumatic chuck, and the other end of which can be respectively connected to the first annular groove and the second annular groove provided on the bearing seat. The sealing component includes a plurality of grid rings, and the plurality of grid rings are arranged one-to-one in a plurality of first sealing grooves on the bearing seat, and the first sealing grooves and the first annular grooves and the second annular grooves are arranged at intervals, so as to realize the sealing of the main shaft and the bearing seat, the first passage and the second passage, and the rotary sealing structure is simple and highly practical. The present invention also discloses a pneumatic chuck mechanism, including the above-mentioned rotary sealing structure and the pneumatic chuck, and its good sealing performance can ensure the clamping degree of the pneumatic chuck and the machining accuracy of the machine tool.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing equipment, and in particular to a rotary sealing structure and a pneumatic chuck mechanism. Background Art

[0002] The pneumatic chuck is a very important part on the machine tool. The compressed air drives the piston in the cylinder to move, thereby realizing the clamping and loosening action of the pneumatic chuck to clamp the workpiece. An airway needs to be opened on the pneumatic chuck to provide air source power. The pneumatic chuck is connected to the machine tool spindle and assembled with the outer shell of the pneumatic chuck through the bearing assembly. There is relative movement between the machine tool spindle and the bearing housing, and there is a gap. When the machine tool starts to prepare for work, it will perform two actions: air inspection and chuck loosening and clamping. At this time, the external air source will enter the spindle through the air nozzle. If the seal is not good, the suspended impurities in the air will enter the spindle, causing wear of the spindle, bearings or other components, affecting the service life and processing performance of the machine tool. At present, the commonly used spindle sealing structure is mainly a labyrinth sealing device, which has a complex structure and cumbersome installation steps.

[0003] Therefore, there is an urgent need for a rotary sealing structure and a pneumatic chuck mechanism to solve the above problems. Summary of the invention

[0004] An object of the present invention is to provide a rotary sealing structure having multiple sealing effects, which can solve the sealing problem during the main shaft rotation air intake process, and has a simple structure and strong practicality.

[0005] As conceived above, the technical solution adopted by the present invention is:

[0006] A rotary sealing structure, comprising:

[0007] A transmission assembly, comprising a spindle, a bearing sleeved on the spindle and a bearing seat, wherein the spindle can be connected to a pneumatic chuck, a first passage and a second passage are provided in the spindle, one end of the first passage and the second passage can be connected to the pneumatic chuck respectively, the first passage is configured to enable the pneumatic chuck to clamp a workpiece, and the second passage is configured to detect whether the workpiece is clamped on the pneumatic chuck;

[0008] A sealing assembly includes a plurality of grid rings, wherein the bearing seat is provided with a first ring groove, a second ring groove and a plurality of first sealing grooves, wherein the plurality of first sealing grooves are arranged at intervals so that the first sealing groove is provided between the first ring groove and the second ring groove, the first sealing groove is provided on a side of the first ring groove away from the second ring groove, and the first sealing groove is provided on a side of the second ring groove away from the first ring groove, wherein one grid ring is arranged in one of the first sealing grooves, and the grid ring is pressed against the main shaft.

[0009] Optionally, the transmission assembly also includes a first ceramic plate and an end cover, and the main shaft is connected to the pneumatic chuck through the first ceramic plate and the end cover, and the first ceramic plate and the end cover are both provided with through holes, and the through holes are configured to connect the first passage and the pneumatic chuck, and connect the second passage and the pneumatic chuck.

[0010] Optionally, the sealing assembly further comprises a plurality of O-rings, the transmission assembly is further provided with a plurality of second sealing grooves, and one of the O-rings is disposed in one of the second sealing grooves;

[0011] The second sealing groove includes two main shaft second sealing grooves arranged on the main shaft, one main shaft second sealing groove ring is arranged outside the first passage, the other main shaft second sealing groove ring is arranged outside the second passage, and two end cover second sealing grooves are opened on the end cover corresponding to the two main shaft second sealing grooves.

[0012] Optionally, two first sealing grooves are provided between the first annular groove and the second annular groove.

[0013] Optionally, a first sealing groove is provided on a side of the first ring groove away from the second ring groove;

[0014] A first sealing groove is provided on a side of the second annular groove away from the first annular groove.

[0015] Another object of the present invention is to provide a pneumatic chuck mechanism which has good spindle sealing performance, can ensure the accuracy of machine tool processing, and has a simple structure and a wide range of applications.

[0016] As conceived above, the technical solution adopted by the present invention is:

[0017] A pneumatic chuck mechanism comprises a pneumatic chuck, a pneumatic component and a rotary sealing structure as described in any one of the above items, wherein the pneumatic chuck is connected to the main shaft, the pneumatic component is configured to be able to pass gas into the first passage so that the pneumatic chuck can clamp a workpiece, and the pneumatic component is configured to be able to pass gas into the second passage to detect whether the workpiece is clamped on the pneumatic chuck.

[0018] Optionally, the pneumatic component includes a first air inlet connector and a second air inlet connector, the first air inlet connector is connected to the first passage, the second air inlet connector is connected to the second passage, and the pneumatic chuck is provided with a clamping portion and an air vent, the clamping portion can be driven to clamp the workpiece, and the air vent can be connected to the second air inlet connector.

[0019] Optionally, the pneumatic chuck mechanism includes a pressure sensor, wherein the pressure sensor is configured to detect an air pressure value in the second passage.

[0020] Optionally, the pneumatic chuck mechanism further includes a chassis and a second ceramic sheet, wherein the chassis is sleeved on the pneumatic chuck and connected to the bearing seat via the second ceramic sheet.

[0021] Optionally, the pneumatic chuck mechanism further comprises a dial, wherein the dial is sleeved on the pneumatic chuck, and the dial is configured to display a rotation angle of the pneumatic chuck.

[0022] The beneficial effects of the present invention are:

[0023] The rotary sealing structure proposed in the present invention includes a transmission component and a sealing component, wherein the transmission component includes a main shaft and a bearing and a bearing seat sleeved on the main shaft. The main shaft is used on a machine tool to drive a workpiece to rotate, and the sealing component is used to seal the gap between the main shaft and the bearing seat. Specifically, a first passage and a second passage are provided in the main shaft, and to ensure the connection between the first passage and the second passage, a first annular groove connected to one end of the first passage and a second annular groove connected to one end of the second passage are provided in the bearing seat. Under this setting, the sealing component must ensure the sealing between the main shaft and the bearing seat, and also the sealing of the first passage and the second passage. Therefore, the sealing component includes a plurality of grid rings sleeved on the main shaft and pressed against the main shaft, and to prevent the grid rings from falling off and loosening, a plurality of first sealing grooves are provided on the bearing seat, and a grid ring is arranged in each first sealing groove. Among them, multiple first sealing grooves are arranged at intervals so that a first sealing groove is provided between the first annular groove and the second annular groove, a second sealing groove is provided on the side of the first annular groove away from the second annular groove, and a first sealing groove is provided on the side of the second annular groove away from the first annular groove, thereby solving the sealing problem during the main shaft rotation and air intake process, with a simple structure and strong practicality.

[0024] The pneumatic chuck mechanism proposed by the present invention includes the rotary sealing structure, the pneumatic chuck and the pneumatic assembly as described above. The pneumatic chuck is connected to the spindle. The pneumatic assembly is used to pass gas into the first passage so that the workpiece can be clamped by the pneumatic chuck. The pneumatic assembly is used to pass gas into the second passage to detect whether the workpiece is clamped on the pneumatic chuck. The pneumatic chuck mechanism with a rotary sealing structure has a better sealing effect when the pneumatic assembly feeds air into the first passage in the spindle, which can prevent the air in the first passage from leaking to the second passage, and prevent the suspended impurities in the air from entering the spindle. This multiple protection provides a guarantee for the high-precision operation of the spindle, ensuring that the pneumatic chuck can clamp the workpiece, thereby ensuring the machining accuracy of the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1is a schematic structural diagram of a pneumatic chuck mechanism provided by an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 The enlarged view of point A in the middle;

[0027] Figure 3 yes Figure 1 The enlarged view of point B in the middle;

[0028] Figure 4 yes Figure 1 Enlarged view of point C in the middle.

[0029] In the figure:

[0030] 1. Spindle; 101. First passage; 102. Second passage; 103. Second sealing groove of spindle; 2. Bearing; 3. Bearing seat; 301. First ring groove; 302. Second ring groove; 303. First sealing groove; 4. First ceramic plate; 5. End cover; 501. Second sealing groove of end cover; 6. Glyd ring; 7. O-ring; 8. Pneumatic chuck; 9. First air inlet connector; 10. Second air inlet connector; 11. Chassis; 12. Second ceramic plate; 13. Dial. DETAILED DESCRIPTION

[0031] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, not all.

[0032] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0035] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0036] Rotary seals are widely used in the field of mechanical processing. Rotary seals are used to prevent gas leakage when pneumatic components supply air to rotating rotating components. For example, there is relative movement between the spindle 1 and the bearing seat 3 of the machine tool, that is, there is a gap. Therefore, when the external air source is fed into the spindle 1, if the seal is not good, the suspended impurities in the air will enter the spindle 1, which will cause the spindle 1, bearing 2 or other parts to wear, affecting the service life and processing performance of the machine tool. Therefore, a rotary seal structure is needed to avoid this problem.

[0037] like Figure 1 As shown, the rotary seal structure provided in this embodiment includes a transmission assembly and a sealing assembly. Specifically, the transmission assembly includes a spindle 1, a bearing 2 and a bearing seat 3. It can be understood that one end of the spindle 1 can be connected to other parts of the machine tool through the bearing 2 and the bearing seat 3, such as a motor, to provide a driving force for the spindle 1 to rotate. The other end of the spindle 1 can be connected to a pneumatic chuck 8. It is known that the pneumatic chuck 8 is used to clamp the workpiece so as to facilitate the next step of processing the workpiece.

[0038] Of course, in order to achieve the clamping of the workpiece by the pneumatic chuck 8, a passage for supplying gas to the pneumatic chuck 8 needs to be provided in the spindle 1. Optionally, in this embodiment, a first passage 101 and a second passage 102 are provided in the spindle 1, and the first passage 101 and the second passage 102 are respectively connected to the pneumatic chuck 8. When the external air source is connected to the pneumatic chuck 8 through the first passage 101, the clamping part of the pneumatic chuck 8 can be clamped or released to clamp or release the workpiece. After the workpiece is clamped, when the external air source is ventilated to the second passage 102, if the workpiece is clamped in the pneumatic chuck 8, the gas will be blocked in the second passage 102 by the workpiece, and if the workpiece is not clamped in the pneumatic chuck 8, the gas will pass through the gap between the pneumatic chuck 8 and the workpiece, and then leak into the external environment. Optionally, the pneumatic chuck 8 may be provided with a vent hole connected to the external environment, and when the workpiece is clamped in the pneumatic chuck 8, the connection between the vent hole and the second through hole will be blocked, and when the workpiece is not clamped in the pneumatic chuck 8, the vent hole and the second through hole will remain connected. In addition, the specific working principle of the pneumatic chuck 8 is common knowledge in the art and will not be described in detail here.

[0039] Under this configuration, in order to ensure the sealing of the main shaft 1 and the bearing seat 3, the communication between the first passage 101 and the second passage 102 and the external gas source, and the separation of the first passage 101 and the second passage 102, a plurality of grid rings 6 are selected in this embodiment for sealing. Specifically, as Figure 1 and Figure 2 As shown, because the first passage 101 needs to be connected to an external air source, both ends of the first passage 101 must be connected to the main shaft 1. In order to ensure the air intake efficiency of the first passage 101, a first annular groove 301 is provided on the bearing seat 3 to increase the gap between the main shaft 1 and the bearing seat 3 at the first passage 101. The first annular groove 301 is arranged in the bearing seat 3 to ensure that the first passage 101 is always connected to the first annular groove 301 during the rotation of the main shaft 1. Figure 1 and Figure 3 As shown, the second passage 102 is similar to the first passage 101, and is also set to pass through the main shaft 1 at both ends. In order to ensure the air intake of the second passage 102, a second annular groove 302 is set on the bearing seat 3 to increase the gap between the main shaft 1 and the bearing seat 3 at the second passage 102. During the rotation of the main shaft 1, the second passage 102 is always connected with the second annular groove 302. Of course, a plurality of first sealing grooves 303 are also set on the bearing seat 3. The number of the first sealing grooves 303 is consistent with the number of the Glyd rings 6. One Glyd ring 6 is set in one first sealing groove 303. It can be seen that the first sealing groove 303 is also an annular structure, and in order to ensure the sealing effect of the Glyd ring 6, a plurality of first sealing grooves 303 are arranged at intervals.

[0040] Optionally, in this embodiment, the first sealing grooves 303 are arranged at intervals such that the first sealing grooves 303 are arranged at intervals on both sides of the first annular groove 301 and the second annular groove 302. Figures 1 to 3 As shown, a first sealing groove 303 is provided between the first annular groove 301 and the second annular groove 302, a first sealing groove 303 is provided on the side of the first annular groove 301 away from the second annular groove 302, and a first sealing groove 303 is provided on the side of the second annular groove 302 away from the first annular groove 301. It can be seen that the Glyd ring 6 is composed of a reinforced PTFE square slip ring and an O-type rubber ring. When the Glyd ring 6 is used to abut against the main shaft 1, not only is there almost no blowing and shedding phenomenon, a good sealing effect can be achieved, and the starting resistance can also be reduced. Figure 1 As shown, Glyd rings 6 are arranged in the two first sealing grooves 303 on both sides of the first passage 101, so as to seal the first passage 101 and prevent the gas from flowing through the upper bearing 2, and Glyd rings 6 are arranged in the two first sealing grooves 303 on both sides of the second passage 102, so as to seal the second passage 102. At the same time, the two Glyd rings 6 between the first passage 101 and the second passage 102 can separate the first passage 101 from the second passage 102 to achieve a double sealing effect.

[0041] like Figure 1 As shown, in this embodiment, two first sealing grooves 303 are provided between the first annular groove 301 and the second annular groove 302. However, in other embodiments, more than one first sealing groove 303 may be provided according to the sealing requirements and the starting load of the main shaft 1.

[0042] Similarly, in this embodiment, a first sealing groove 303 is provided on the side of the first annular groove 301 away from the second annular groove 302. However, in other embodiments, more than one first sealing groove 303 may be provided according to the sealing requirements and the starting load of the main shaft 1. In this embodiment, a first sealing groove 303 is also provided on the side of the second annular groove 302 away from the first annular groove 301. In other embodiments, more than one first sealing groove 303 may still be provided according to the sealing requirements and the starting resistance of the main shaft 1.

[0043] In addition, refer to Figure 1It can be seen that the transmission assembly also includes a first ceramic sheet 4 and an end cover 5. In this embodiment, the spindle 1 is connected to the pneumatic chuck 8 through the first ceramic sheet 4 and the end cover 5. Among them, the end cover 5 and the pneumatic chuck 8 are fixedly connected by screws passing through the middle of the two, and the first ceramic sheet 4 is an insulator, which can effectively isolate the current from the end cover 5 to the spindle 1, and prevent part of the current from passing through the spindle 1 to the motor driving the spindle 1 to rotate when the pneumatic chuck 8 clamps the electrode, so as to ensure the safety of the equipment. Of course, in order to ensure that the first passage 101 and the second passage 102 can be connected to the pneumatic chuck 8, through holes should also be provided on the first ceramic sheet 4 and the end cover 5. Optionally, two through holes are respectively provided on the first ceramic sheet 4 and the end cover 5, that is, one of the through holes is connected to the first passage 101, and the other through hole is connected to the second passage 102.

[0044] When the first ceramic sheet 4 is used to isolate the end cover 5 and the main shaft 1, although the two are fixed by fasteners, there is inevitably a gap in the mechanical fixation, which may cause leakage of gas when it flows into the through hole from the first passage 101 and the second passage 102. In this embodiment, the sealing assembly also includes a plurality of O-rings 7 arranged at the first ceramic sheet 4, which is similar to the arrangement of the Glyd ring 6. It is necessary to firstly arrange a plurality of second sealing grooves on the transmission assembly, and then arrange an O-ring 7 in each second sealing groove.

[0045] Specifically, Figure 4 As shown, the second sealing groove includes two spindle second sealing grooves 103 arranged on the spindle 1, and one spindle second sealing groove 103 is arranged outside the first passage 101, and the other spindle second sealing groove 103 is arranged outside the second passage 102. Optionally, when the O-ring 7 is placed in the spindle second sealing groove 103, the gas can pass through the middle of the O-ring 7, and when the O-ring 7 is placed in the spindle second sealing groove 103, the first ceramic sheet 4 is connected to the spindle 1, and the O-ring 7 is sandwiched between the two aforementioned, and abuts against the two aforementioned, so as to achieve sealing. Two end cover second sealing grooves 51 are opened on the end cover 5 corresponding to the two spindle second sealing grooves 103, and an O-ring 7 is arranged in one end cover second sealing groove 51, and when the end cover 5 is connected to the pneumatic chuck 8, the O-ring 7 can abut against the two aforementioned, so as to achieve sealing.

[0046] To further illustrate the wide application of the rotary seal structure on machine tools, the present embodiment further provides a pneumatic chuck mechanism, including the rotary seal structure and the pneumatic chuck 8 as described above. In addition, based on the working principle of the pneumatic chuck 8, a pneumatic component is also provided to provide an external air source to the pneumatic chuck 8. When the pneumatic chuck 8 is connected to the spindle 1, the pneumatic component can pass gas into the first passage 101. When the gas enters the one-way valve of the pneumatic chuck 8, the workpiece can be clamped on the pneumatic chuck 8. However, after the workpiece has been clamped on the pneumatic chuck 8, the first passage 101 is no longer ventilated, but the pneumatic component is used to ventilate the second passage 102. If the gas entering the second passage 102 leaks into the external environment through the pneumatic chuck 8, it means that the workpiece is not completely clamped on the pneumatic chuck 8.

[0047] In this embodiment, Figure 1 As shown, the pneumatic assembly includes a first air inlet connector 9 and a second air inlet connector 10, wherein the first air inlet connector 9 is connected to the first passage 101, and the second air inlet connector 10 is connected to the second passage 102. Optionally, the first air inlet connector 9 and the second air inlet connector 10 are arranged on the same side, and the first passage 101 and the second passage 102 can be arranged on both sides respectively. After the external air source is injected into the pneumatic chuck 8 through the first air inlet connector 9, the clamping part on the pneumatic chuck 8 can be pushed to move to clamp the workpiece. After clamping, the first air inlet connector 9 stops venting, and the cylinder of the clamping part is in a pressure-maintaining state to clamp the workpiece. Thereafter, the second passage 102 can be ventilated through the second air inlet connector 10. If the workpiece is in a clamped state, the gas in the second passage 102 will not be able to leak through the vent hole arranged on the pneumatic chuck 8, that is, the workpiece will become an obstacle for the second passage 102 to be connected to the vent hole, but if the workpiece is loose, the gas will overflow from the vent hole.

[0048] Furthermore, the pneumatic chuck mechanism provided in this embodiment further includes a pressure sensor, which is used to detect in real time the air pressure value in the second passage 102. Optionally, the pressure sensor can be connected to an alarm by signal, and when the air pressure value detected by the pressure sensor is less than a preset value, a signal is transmitted to the alarm to remind the staff to check the clamping condition of the workpiece.

[0049] Optionally, the pneumatic chuck mechanism also includes a chassis 11 and a second ceramic plate 12. In this embodiment, the pneumatic chuck 8 is connected to the end cover 5 by screws, and the chassis 11 is mounted on the end cover 5 and the pneumatic chuck 8 to protect both. When the pneumatic chuck 8 mechanism is applied to an electric spark machine, brushes and the like will be arranged in the chassis 11. Therefore, the chassis 11 also needs to be connected to the bearing seat 3 through the second ceramic plate 12. It can be known that the second ceramic plate 12 is an insulating part.

[0050] Optionally, the pneumatic chuck mechanism further includes a scale plate 13 , which is sleeved on the pneumatic chuck 8 , and is used to record the rotation angle of the pneumatic chuck 8 .

[0051] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A rotary sealing structure, characterized in that: include: A transmission assembly comprises a main shaft (1), a bearing (2) sleeved on the main shaft (1) and a bearing seat (3); the main shaft (1) can be connected to a pneumatic chuck (8); a first passage (101) and a second passage (102) are provided in the main shaft (1); one end of the first passage (101) and one end of the second passage (102) can be connected to the pneumatic chuck (8) respectively; a vent hole connected to an external environment is provided on the pneumatic chuck (8); the first passage (101) is configured to enable the pneumatic chuck (8) to clamp a workpiece; and the second passage (102) is configured to detect whether the workpiece is clamped on the pneumatic chuck (8); A sealing assembly, comprising a plurality of grid rings (6), the bearing seat (3) being provided with a first ring groove (301), a second ring groove (302) and a plurality of first sealing grooves (303), the plurality of first sealing grooves (303) being arranged at intervals so that the first sealing groove (303) is arranged between the first ring groove (301) and the second ring groove (302), the first sealing groove (303) is arranged on a side of the first ring groove (301) away from the second ring groove (302), and the first sealing groove (303) is arranged on a side of the second ring groove (302) away from the first ring groove (301), one grid ring (6) is arranged in one of the first sealing grooves (303), and the grid ring (6) is pressed against the main shaft (1); The transmission assembly further comprises a first ceramic sheet (4) and an end cover (5), the spindle (1) being connected to the pneumatic chuck (8) via the first ceramic sheet (4) and the end cover (5), the first ceramic sheet (4) and the end cover (5) both being provided with through holes, the through holes being configured to connect the first passage (101) and the pneumatic chuck (8), and to connect the second passage (102) and the pneumatic chuck (8); The sealing assembly further comprises a plurality of O-rings (7), the transmission assembly is further provided with a plurality of second sealing grooves, and one of the O-rings (7) is arranged in one of the second sealing grooves; The second sealing groove comprises two main shaft second sealing grooves (103) provided on the main shaft (1), one of the main shaft second sealing grooves (103) being arranged outside the first passage (101), the other main shaft second sealing groove (103) being arranged outside the second passage (102), and two end cover second sealing grooves (51) provided on the end cover (5) corresponding to the two main shaft second sealing grooves (103).

2. The rotary sealing structure according to claim 1, characterized in that: Two first sealing grooves (303) are provided between the first annular groove (301) and the second annular groove (302).

3. The rotary sealing structure according to claim 1, characterized in that: A first sealing groove (303) is provided on a side of the first annular groove (301) away from the second annular groove (302); A first sealing groove (303) is provided on a side of the second annular groove (302) away from the first annular groove (301).

4. A pneumatic chuck mechanism, characterized in that: The invention comprises a pneumatic chuck (8), a pneumatic component and a rotary sealing structure as claimed in any one of claims 1 to 3, wherein the pneumatic chuck (8) is connected to the main shaft (1), the pneumatic component is configured to be able to pass gas into the first passage (101) so that the pneumatic chuck (8) can clamp a workpiece, and the pneumatic component is configured to be able to pass gas into the second passage (102) so as to detect whether the workpiece is clamped on the pneumatic chuck (8).

5. The pneumatic chuck mechanism according to claim 4, characterized in that: The pneumatic assembly comprises a first air inlet connector (9) and a second air inlet connector (10), wherein the first air inlet connector (9) is connected to the first passage (101), and the second air inlet connector (10) is connected to the second passage (102), and the pneumatic chuck (8) is provided with a clamping portion and an air vent, wherein the clamping portion can be driven to clamp the workpiece, and the air vent can be connected to the second air inlet connector (10).

6. The pneumatic chuck mechanism according to claim 5, characterized in that: The pneumatic chuck mechanism further comprises a pressure sensor, which is configured to detect the air pressure value in the second passage (102).

7. The pneumatic chuck mechanism according to claim 4, characterized in that: The pneumatic chuck mechanism further comprises a chassis (11) and a second ceramic plate (12); the chassis (11) is sleeved on the pneumatic chuck (8) and connected to the bearing seat (3) via the second ceramic plate (12).

8. The pneumatic chuck mechanism according to claim 4, characterized in that: The pneumatic chuck mechanism further comprises a dial (13), wherein the dial (13) is sleeved on the pneumatic chuck (8), and the dial (13) is configured to display the rotation angle of the pneumatic chuck (8).

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