Rotary shaft gas seal

Abstract

The utility model discloses a kind of rotary shaft air seal devices, comprising: the base body of being sleeved on rotary shaft, the transition disc is installed at the top of base body, the air inlet hole is provided on the base body, the air inlet hole is communicated with the transition disc by first gas path, the transition disc is communicated with the rotary shaft by second gas path, when compressed air evenly enters first gas path and second gas path, transition disc, base body and rotary shaft are compressed and sealed. By different gas path, compressed air is evenly blown into the N inner holes opened in transition disc by base body air inlet hole, then pass through the radial annular groove on transition disc and blow into the radial annular groove of rotary shaft, so that compressed air is more uniform, and siphon phenomenon cannot be formed, air seal effect is reliable and excellent, effectively prolong the service life of precision moving part.

Description

Technical Field

[0001] This utility model relates to the field of mechanical seal technology, and in particular to a rotary shaft gas seal device. Background Technology

[0002] The application of air-sealing devices in rotating shafts not only protects the precision moving parts of the shaft from contamination by coolant and machining chips, ensuring the rotational accuracy of the shaft, but also extends the service life of the precision moving parts. Therefore, the rational design of air-sealing structures is a key common technology for equipment requiring high precision and high stability rotational functions.

[0003] Traditional rotary shaft air seal devices involve compressed air entering through a single air hole and then blowing into a radial or end-face annular groove. This results in uneven air pressure, with higher pressure near the air source and lower pressure further away, leading to unreliable sealing performance. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies, the purpose of this utility model is to provide a rotary shaft air sealing device.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] A rotary shaft air-sealing device includes: a base fitted on a rotary shaft, a transition plate installed at the top of the base, an air inlet on the base, the air inlet being connected to the transition plate through a first air passage, and the transition plate being connected to the rotary shaft through a second air passage. When compressed air enters the first and second air passages evenly, it presses and seals the transition plate, the base, and the rotary shaft.

[0007] The first air passage includes: an air port disposed on the substrate, a first end face annular groove formed on the end face of the substrate, a second end face annular groove formed on the end face of the transition plate that mates with the first end face annular groove, and the air port being connected to the first end face annular groove through a first air passage.

[0008] The second air passage includes: an inner hole is radially arranged at the bottom of the annular groove on the first end face of the transition plate; a first radial annular groove communicating with the inner hole is opened on the transition plate; and a second radial annular groove that cooperates with the first radial annular groove is opened on the rotating shaft.

[0009] The bottom of the annular groove on the first end face has multiple inner holes arranged radially and evenly.

[0010] The transition plate is fixed to the end face of the base by screws.

[0011] A bearing is installed between the base and the rotating shaft, and the rear end of the base is pressed together by a pressure cap.

[0012] The bearings are provided with an inner spacer and an outer spacer for adjusting the bearing preload.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] This utility model provides a rotary shaft air sealing device. Compressed air is evenly blown from the base air inlet into N inner holes of the transition plate through different air paths, and then blown into the radial annular groove of the rotary shaft through the radial annular groove on the transition plate. This makes the compressed air more uniform, prevents siphoning, and provides a reliable and excellent air sealing effect, effectively extending the service life of precision moving parts. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the rotating shaft air-sealing device of this utility model;

[0016] Figure 2 This is the overall installation diagram of the rotary shaft air-sealing device of this utility model.

[0017] In the figure, 1—spindle motor; 2—nut; 3—spacer; 4—gland; 5—bearing; 6—base; 61—air port; 7—transition plate; 8—rotating shaft; 9—second radial annular groove; 10—first radial annular groove; 11—inner hole; 12—second end face annular groove; 13—first end face annular groove; 14—inner spacer; 15—outer spacer. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0019] like Figure 1 , 2As shown, this utility model provides a rotary shaft air-sealing device, including a base 6 fitted onto a rotary shaft 8, with a transition plate 7 mounted on the top of the base 6. The base 6 has an air inlet, which is connected to the transition plate 7 via a first air passage. The transition plate 7 is connected to the rotary shaft 8 via a second air passage. When compressed air enters the first and second air passages evenly, the gap between the transition plate 7, the base 6, and the rotary shaft 8 is reduced, ensuring a seal. A bearing 5 is installed between the base 6 and the rotary shaft 8, and the rear end of the base 6 is pressed by a pressure cap 4. The transition plate 7 is connected to the base 6 by screws. The inner hole of the bearing 5 has an interference fit with the outer circle of the rotary shaft 8 and a small clearance fit with the base 6. The bearing 5 is installed between the base 6 and the rotary shaft 8, and the rear end of the base 6 is pressed by the pressure cap 4. The pressure cap 4 is fixed to the base 6 by a fastening nut 2.

[0020] The first air passage includes an air port 61 disposed on the base 6, a first end face annular groove 13 is formed on the end face of the base 6, a second end face annular groove 12 is formed on the end face of the transition plate 7 that cooperates with the first end face annular groove 13, and the air port 61 is connected to the first end face annular groove 13 through a first air passage.

[0021] The second air passage includes: an inner hole 11 radially arranged at the bottom of the annular groove 13 on the first end face of the transition plate 7; a first radial annular groove 10 communicating with the inner hole 11 on the transition plate 7; and a second radial annular groove 9 cooperating with the first radial annular groove 10 on the rotating shaft 8. For example, N inner holes 11 are radially and evenly arranged at the bottom of the annular groove 13 on the first end face. The first radial annular groove 10 is formed in the inner hole 11 of the transition plate 7, connecting the N inner holes 11. The second radial annular groove 9 is formed on the outer circumference of the rotating shaft 8, opposite to the first radial annular groove 10 on the inner hole of the transition plate 7. Compressed air enters through the air inlet 61 and is blown out from the radial annular groove of the rotating shaft. The radial fit clearance between the transition plate and the rotating shaft is different, ensuring that the gas is evenly blown out from the end with the larger fit clearance along the radial circle of the rotating shaft, effectively preventing external contaminants from entering the interior of the rotating shaft and ensuring a sealing effect.

[0022] The rotating shaft 8 is directly driven by the motor spindle 1. During operation, compressed air is continuously blown from the first radial annular groove 10 to the second radial annular groove 9. The inner hole 11 of the transition plate 7 is divided in the axial direction by the first radial annular groove 10. The gap values ​​between the two sides of the radial annular groove and the rotating shaft are different, and the sealing effect is ensured by the different gap values.

[0023] Firstly, in terms of structure, to achieve a sealing effect, mating sections a and b with different radial clearances between the transition plate 7 and the main shaft are designed. According to fluid analysis, it is only necessary to meet the following requirements: the single-sided clearance value between the shaft diameter section a and the transition plate is 0.5-0.6, the single-sided clearance value between the diameter section b and the transition plate is 0.15-0.2, the compressed air intake pressure is not less than 4 bar, and the number of N evenly distributed inner holes on the transition plate 7 should be as large as possible. The more inner holes there are, the more uniform the amount of air blown out along the radial direction of the transition plate 7 and the rotating shaft 8 will be.

[0024] Secondly, in terms of manufacturing process, in order to prevent the poor coaxiality of the transition plate and the rotating shaft due to defects in the roundness and cylindricity of the parts themselves, resulting in uneven air pressure and insufficient local air pressure, thus affecting the air sealing effect, the coaxiality of the inner hole 61 of the transition plate 7 and the outer diameter of the rotating shaft must be ≤0.01.

[0025] The rotary shaft air-sealing device of this utility model is tooled as follows: the spindle motor 1 drives the spindle to rotate, and the front and rear ends are supported by high-precision angular contact spindle bearings in a four-front-two-rear layout. The bearings 5 ​​are adjusted by the inner and outer spacers 14 and 15 to adjust the bearing preload. A high-precision angle encoder is used at the rear end for speed and position feedback. The working environment of the spindle is one where grinding coolant is constantly sprayed, so it is necessary to ensure good spindle sealing to prevent contamination of the spindle bearings and encoder, which would affect the normal operation of the machine tool. Therefore, after the machine tool is powered on, compressed air enters the air inlet of the base 6, passes through the first end face annular groove 13 and the second end face annular groove 12, and enters the N small holes 11 evenly distributed in the transition plate 7. Then, it is evenly blown out through the first radial annular groove 10 to the second radial annular groove 9. The radial annular grooves have a larger gap away from the bearing end and a smaller gap near the bearing end. The gap value is determined by fluid analysis results, which ensures that the direction of compressed air is away from the bearing end and that the compressed air pressure is uniform, preventing siphoning. The air-sealing effect is reliable and excellent, effectively extending the service life of the bearings and encoder.

[0026] The working process of this utility model is as follows:

[0027] 1. An air inlet 61 is opened on the base 6. A first end face annular groove 13 is opened at the end of the base 6. The air inlet 61 is connected to the first end face annular groove 13. A second end face annular groove 12 is opened on the transition plate 7. N inner holes 11 are evenly distributed on the annular groove of the transition plate 7. It is required that the air inlet hole is not opposite to any of the N small holes.

[0028] 2. A first radial annular groove 10 communicating with N small holes is opened on the transition plate 7, and a second radial annular groove 9 is opened on the rotating shaft 8, requiring the first radial annular groove 10 and the second radial annular groove 9 to be set opposite to each other.

[0029] 3. The inner holes on both sides of the radial annular groove of the transition plate 7 have different clearances from the rotating shaft. The clearance value closer to the bearing 5 is smaller than the clearance value farther from the bearing 5.

[0030] It will be apparent to those skilled in the art that the above specific examples are merely preferred embodiments of this utility model. Therefore, any improvements or modifications that those skilled in the art may make to certain parts of this utility model still embody the principles of this utility model and achieve its purpose, and all fall within the scope of protection of this utility model.

Claims

1. A rotary shaft gas sealing device, characterized in that, include: A base (6) is mounted on a rotating shaft (8). A transition plate (7) is installed at the top of the base (6). An air inlet is provided on the base (6). The air inlet is connected to the transition plate (7) through a first air passage. The transition plate (7) is connected to the rotating shaft (8) through a second air passage. When compressed air enters the first air passage and the second air passage evenly, the transition plate (7), the base (6), and the rotating shaft (8) are pressed and sealed.

2. The rotary shaft gas sealing device according to claim 1, characterized in that, The first air passage includes: an air port (61) disposed on the substrate (6), the end face of the substrate (6) is provided with a first end face annular groove (13), the end face of the transition plate (7) is provided with a second end face annular groove (12) that cooperates with the first end face annular groove (13), and the air port (61) is connected to the first end face annular groove (13) through a first air passage.

3. The rotary shaft gas sealing device according to claim 2, characterized in that, The second air passage includes: an inner hole (11) is radially arranged at the bottom of the first end face annular groove (13) of the transition plate (7); a first radial annular groove (10) communicating with the inner hole (11) is opened on the transition plate (7); a second radial annular groove (9) cooperating with the first radial annular groove (10) is opened on the rotating shaft (8).

4. The rotary shaft gas sealing device according to claim 3, characterized in that, The bottom of the first end face annular groove (13) has multiple inner holes (11) arranged radially and evenly.

5. The rotary shaft gas sealing device according to claim 1, characterized in that, The transition plate (7) is fixed to the end face of the base (6) by screws.

6. The rotary shaft gas sealing device according to claim 1, characterized in that, A bearing (5) is installed between the base (6) and the rotating shaft (8), and the rear end of the base (6) is pressed by a pressure cap (4).

7. The rotary shaft gas sealing device according to claim 6, characterized in that, An inner spacer (14) and an outer spacer (15) for adjusting the bearing preload are provided between the bearings (5).

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