JP6769777B2 - Air turbine drive spindle - Google Patents

Description

The present invention relates to an air turbine drive spindle applied to precision processing machines, electrostatic coating devices and the like.

Conventionally, an air turbine drive spindle (hereinafter, also referred to as a spindle) used in a precision processing machine or an electrostatic coating device is known. For example, Japanese Patent Application Laid-Open No. 9-7238 discloses a spindle in which a bearing member that rotatably supports a rotating shaft is held in a housing.

Spindles for electrostatic coating machines are usually operated under the condition that a cup is attached to the tip of a rotating shaft and the number of rotations per minute is tens of thousands. Here, a problem such as an unbalance of the cup attached to the tip of the rotating shaft may cause one vibration (primary vibration) for each rotation of the rotating shaft. This vibration adversely affects the entire coating machine, lowers the coating quality, and also adversely affects the performance of the hydrostatic bearings constituting the spindle, and abnormal vibration may occur.

Therefore, the air spindle for the coating machine needs a mechanism to absorb vibration. In JP-A-9-72338, the bearing member is supported by an O-ring with respect to the housing. Such an O-ring is usually made of an elastic body such as rubber. The O-ring has a function of absorbing and attenuating the vibration generated by the high-speed rotation of the rotating shaft of the spindle and stabilizing the operation of the spindle.

JP-A-9-72338A

In the air turbine drive spindle, it is expected that the adverse effect of vibration can be suppressed and the unbalance resistance performance can be improved by enhancing the vibration absorbing performance, that is, the damping performance. Therefore, it is important to improve such damping performance. To improve the damping performance of the spindle, an O-ring with high damping performance may be selected.

Here, since the electrostatic coating device or the like in which the spindle is used is used in a solvent atmosphere, it is necessary to use a material having excellent solvent resistance for the above-mentioned O-ring. A perfluoroelastomer is known as such a material having excellent solvent resistance. The perfluoroelastomer has excellent solvent resistance, but has a higher hardness than rubber materials generally used for O-rings (for example, fluororubber and nitrile rubber). As a result, the O-ring made of perfluoropolymer has a smaller amount of deformation with respect to an external force than a general O-ring. For this reason, the vibration caused by the rotation of the rotating shaft cannot be sufficiently absorbed by the O-ring, and as a result, the rotating shaft of the spindle may not be stably rotated at high speed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an air turbine drive spindle capable of stably rotating a rotating shaft at a high speed.

An air turbine drive spindle according to the present invention includes a rotating shaft, a bearing portion, a support member, a cover member, and at least one or more O-rings. The bearing portion surrounds at least a part of the outer peripheral surface of the rotating shaft. The support member is arranged on the outer peripheral side of the bearing portion. The cover member is arranged on the outer peripheral side of the support member, and houses the rotating shaft, the bearing portion, and the support member. A part of the support member is fixed to either the bearing portion or the cover member. At least one or more O-rings are arranged in a gap between the support member and any one of the bearing portion and the cover member at a position not overlapping the above-mentioned part of the support member in the thrust direction of the rotation axis.

According to the present invention, it is possible to realize an air turbine drive spindle capable of stably rotating the rotating shaft at high speed by improving the damping performance against vibration by the support member and the O-ring.

It is sectional drawing of the cross-section of the air turbine drive spindle which concerns on Embodiment 1. FIG. FIG. 5 is a schematic partial cross-sectional view of the air turbine drive spindle according to the first embodiment. It is a partial cross-sectional schematic diagram of the air turbine drive spindle which concerns on Embodiment 2. FIG. FIG. 5 is a schematic partial cross-sectional view of the air turbine drive spindle according to the third embodiment. It is a partial cross-sectional schematic diagram of the air turbine drive spindle which concerns on Embodiment 4. FIG. It is a perspective schematic view of the damper ring of the air turbine drive spindle shown in FIG. FIG. 5 is a schematic partial cross-sectional view of the air turbine drive spindle according to the fifth embodiment. It is an enlarged sectional schematic diagram for demonstrating the function of the seal O-ring which concerns on this embodiment. It is a schematic view of the enlarged cross section of the region IX of FIG. It is an enlarged cross-sectional schematic diagram of the O-ring for a seal which concerns on a reference example, when the bearing gas is not supplied. FIG. 5 is a schematic enlarged cross-sectional view of region XI in FIG. It is an enlarged cross-sectional schematic diagram when the bearing gas is supplied about the seal O-ring which concerns on a reference example. It is an enlarged sectional schematic diagram of the region XIII of FIG. It is an enlarged sectional schematic diagram for demonstrating the deformation example of the groove in which the seal O-ring is arranged. It is a schematic view of the enlarged cross section of the region XV of FIG. It is an enlarged sectional schematic diagram for demonstrating the deformation example of the groove in which the seal O-ring is arranged. FIG. 6 is a schematic enlarged cross-sectional view of region XVII of FIG. It is an enlarged sectional schematic diagram for demonstrating the deformation example of the groove in which the seal O-ring is arranged. FIG. 5 is a schematic enlarged cross-sectional view of region XIX in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts will be given the same reference number and the description will not be repeated.

(Embodiment 1)
<Structure of air turbine drive spindle>
The configuration of the air turbine drive spindle 200 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view of the air turbine drive spindle 200 according to the present embodiment. FIG. 2 is a schematic partial cross-sectional view of the air turbine drive spindle 200 according to the present embodiment.

The air turbine drive spindle 200 includes a rotating shaft 1, a journal bearing 7 that supports the rotating shaft 1 in the radial direction, a thrust bearing 8 that supports the rotating shaft 1 in the thrust direction (axial direction), and a journal bearing that supports the rotating shaft 1. A bearing portion 2 rotatably supported via the thrust bearing 8 and a thrust bearing 8, a damper ring 50 as a support member located on the outer peripheral side of the bearing portion 2, and a cover member 5 located on the outer peripheral side of the damper ring 50. A plurality of O-rings 24 arranged between the bearing portion 2 and the damper ring 50 are mainly provided. The outer peripheral surface of the fixing portion 55, which is a part of the damper ring 50, is a fixing surface 55a, and is fixed to the cover member 5 via the fixing surface 55a. The O-ring 24 is arranged at a position in the gap between the damper ring 50 and the bearing portion 2 so as not to overlap the fixed portion 55 of the damper ring 50 in the thrust direction of the rotating shaft 1. Hereinafter, the configuration of the air turbine drive spindle 200 will be described more specifically.

A nozzle plate 6 is fixedly provided on the cover member 5 so as to cover the rotation shaft 1 in the thrust direction. The cover member 5 surrounds at least a part of the outer peripheral surface 3a of the housing 3 included in the bearing portion 2. A driving gas supply unit (not shown) is connected to the nozzle plate 6. The journal bearing 7 and the thrust bearing 8 are configured as, for example, a hydrostatic gas bearing.

The rotating shaft 1 includes a shaft portion 1b having a cylindrical shape and a thrust plate portion 1c formed so as to extend in the radial direction with respect to the shaft portion 1b. The thrust plate portion 1c is coupled to one end of the shaft portion 1b in the thrust direction. Hereinafter, the side in which the thrust plate portion 1c is provided in the thrust direction is referred to as "rear side", and the side opposite to the rear side in the thrust direction of the shaft portion 1b is referred to as "front side".

A through hole 17 extending in the thrust direction is formed in the shaft portion 1b and the thrust plate portion 1c. When the air turbine drive spindle 200 is configured for an electrostatic coating machine, a conical cup 80 is attached to the front end of the rotating shaft 1. A paint supply pipe 45 for supplying paint to the cup 80 is arranged inside the through hole 17. The thrust plate portion 1c is formed with a rotary blade 15 and a rotated detection portion (not shown) arranged on the inner peripheral side of the rotary blade 15.

A part of the shaft portion 1b of the rotating shaft 1 is housed in the bearing portion 2. The bearing portion 2 includes a housing 3 and a bearing sleeve 4. The housing 3 corresponds to one embodiment of the "housing member". The bearing sleeve 4 corresponds to one embodiment of the "bearing member". The bearing sleeve 4 faces each part of the outer peripheral surface 1a of the shaft portion 1b of the rotating shaft 1 and the front plane of the thrust plate portion 1c, and is formed so as to surround a part of the shaft portion 1b. The housing 3 is arranged on the outer peripheral side of the bearing sleeve 4 in the radial direction and is fixed to the bearing sleeve 4. The housing 3 surrounds at least a part of the outer peripheral surface 1a of the shaft portion 1b from the outer peripheral side of the bearing sleeve 4.

The thrust plate portion 1c of the rotating shaft 1 has a thin-walled portion in a region located on the outer peripheral side in the radial direction. The thin-walled portion is a region having a thinner thickness in the thrust direction than the region (thick-walled portion) located on the rotation center axis side (center side). The thick portion is formed so as to surround the through hole 17. The thin-walled portion is formed so as to surround the thick-walled portion.

The rotary blade 15 is formed so as to extend in the thrust direction from the surface located on the rear side on the thin-walled portion of the thrust plate portion 1c. The rotary shaft 1 is provided so that the rotary blade 15 can rotate by receiving the gas (also referred to as the drive gas) ejected from the drive gas supply unit. The plurality of rotary blades 15 are provided so as to be spaced apart from each other in the rotation direction of the rotation shaft 1. Preferably, in the plurality of rotary blades 15, adjacent rotary blades 15 are provided at equal intervals. The plurality of rotary blades 15 are arranged along the outer circumference of the thrust plate portion 1c. The cross-sectional shape of the plurality of rotary blades 15 perpendicular to the thrust direction may be any shape. For example, the cross-sectional shape is a front curved surface portion located forward in the rotation direction and formed convex in the rotation direction, and a rear curved surface portion located rearward in the rotation direction and formed convex in the rotation direction. It has a part.

In the thrust plate portion 1c, the boundary region between the thin-walled portion and the thick-walled portion is provided so that the thickness in the thrust direction gradually changes. That is, the surface located on the rear side of the thrust plate portion 1c has a curved surface between the thin-walled portion and the thick-walled portion.

A rotation-detected portion (not shown) is formed on the rear surface of the thick portion of the thrust plate portion 1c. The rotated detection unit can adopt an arbitrary configuration for optically detecting the rotation of the rotation shaft 1, but for example, the surface treatment is performed so that the reflectance is different for each of a plurality of regions divided in the rotation direction. It may be given. Specifically, of the surfaces located on the rear side of the thick portion, when half of the area of the rotation axis 1 in the rotation direction is irradiated with light such as laser light, the reflected light is more than the other half. It is provided so that the strength is high.

The supply unit 100 is, for example, an air compressor, and supplies (spouts) gas (also referred to as bearing gas) from the supply port 9. A bearing supply path 10 is formed in a part of the cover member 5, the damper ring 50, the housing 3, and the bearing sleeve 4 in the radial direction. The bearing supply path 10 communicates with the gap 44 formed between the damper ring 50 and the housing 3 via the communication hole portion 25. The bearing gas supplied from the supply port 9 by the supply unit 100 flows into the gap 44 via the communication hole portion 25 via the bearing supply path 10. The bearing gas is, for example, compressed air. The gap 44 corresponds to one embodiment of the "first gap". The fixed surface 55a of the damper ring 50 is brought into close contact with the surface of the cover member 5, so that the holes formed in the cover member 5 constituting the bearing supply path 10 and the holes formed in the damper ring 50 are airtight. It is connected.

A gap 41 is formed between the shaft portion 1b and the bearing sleeve 4. A gap 42 is formed between the thrust plate portion 1c and the bearing sleeve 4. The bearing supply path 10 communicates with each of the gap 41 and the gap 42. A so-called throttle is formed because the hole diameter of the portion of the bearing supply path 10 communicating with the gap 41 and the gap 42 is smaller than the hole diameter of the supply port 9. When the bearing gas is supplied from the supply unit 100, the bearing supply path 10 and the voids 41, 42, 44 are filled with the bearing gas.

The journal bearing 7 is configured by supplying the bearing gas supplied from the supply unit 100 to the bearing supply path 10 to the gap 41. The thrust bearing 8 is composed of a pressing force and an attractive force of the magnet 16 by supplying the bearing gas supplied from the supply unit 100 to the bearing supply path 10 to the gap 42.

In the housing 3, a magnet 16 is arranged in a region facing the thrust plate portion 1c in the thrust direction. The magnet 16 applies a magnetic force to the thrust plate portion 1c. The magnet 16 is, for example, a permanent magnet. The magnet 16 attracts the thrust plate portion 1c by magnetic force. The magnet 16 is provided so as to face the thin portion of the thrust plate portion 1c on which the rotary blade 15 is formed, for example, in the thrust direction. The plane shape of the magnet 16 when viewed from the thrust direction is, for example, an annular shape.

The cover member 5 is fixed to the nozzle plate 6 in the thrust direction. The nozzle plate 6 surrounds a portion of the rotating shaft 1 that is not accommodated in the bearing portion 2 and the cover member 5 (the outer peripheral end surface of the thrust plate portion 1c in the radial direction and the surface located behind the thrust plate portion 1c). It is formed.

The nozzle plate 6 is arranged on the rear side of the rotation shaft 1. A drive air supply path 13 and a drive air supply nozzle 14 are formed inside the nozzle plate 6. One end of the drive air supply passage 13 communicates with the drive gas air supply port 12 on the inner peripheral surface of the nozzle plate 6, and the other end communicates with the drive air supply nozzle 14. The drive air supply passage 13 and the drive air supply nozzle 14 are flow passages for supplying the drive gas to the rotary blade 15. The driving gas is, for example, compressed air. The drive gas supply unit (not shown) that supplies the drive gas from the drive gas air supply port 12 may also be used as the supply unit 100, or may be different from the supply unit 100. Good.

The drive air supply nozzle 14 can eject the drive gas to the rotary blade 15 from the outer peripheral side to the inner peripheral side of the rotary shaft 1 in the radial direction. A plurality of drive air supply passages 13 and drive air supply nozzles 14 may be formed at intervals in the rotation direction. That is, the drive air supply passage 13 and the drive air supply nozzle 14 can simultaneously supply the drive gas in the same rotation direction to the rotor blades 15 provided at arbitrary intervals in the rotation direction. There may be.

The nozzle plate 6 is formed with a rotation sensor insertion port 18 on the outer peripheral side in the radial direction with respect to the through hole 17. The rotation sensor insertion port 18 is formed so as to face the rotated detection unit installed in the thrust plate portion 1c in the thrust direction. The rotation sensor insertion port 18 is formed to irradiate the rotation detection unit with light such as a laser beam and arrange a rotation sensor for obtaining reflected light. With such a configuration, the air turbine drive spindle 200 can optically measure the rotation speed of the rotating shaft 1.

The exhaust hole 11 is formed in the nozzle plate 6 on the central side in the radial direction with respect to the drive air supply passage 13 and the drive air supply nozzle 14. The exhaust hole 11 is formed so as to communicate with the outside of the nozzle plate 6 from the exhaust space 20.

The damper ring 50 is provided in the circumferential direction along the outer peripheral surface 3a of the housing 3 so as to surround the bearing portion 2 on the outer peripheral side of the bearing portion 2 in the radial direction. The outer peripheral surface of the fixing portion 55 of the damper ring 50 is a fixing surface 55a, and the fixing surface 55a is fixed to the cover member 5. By providing the damper ring 50, the air turbine drive spindle 200 has a mechanism for absorbing or attenuating the vibration in two stages of the O-ring 24 and the damper ring 50 in the radial direction. The damper ring 50 corresponds to one embodiment of the "support member".

The shape of the damper ring 50 according to the present embodiment will be described. The damper ring 50 is a hollow annular member, and is mainly located in front of the center of gravity 29 (see FIG. 1) of the air turbine drive spindle 200, and is mainly located in front of the center of gravity 29 (see FIG. 1). It includes a rear portion 52 arranged on the rear side and a fixing portion 55 as an intermediate portion arranged between the front side portion 51 and the rear side portion 52. The fixing portion 55 is formed with a plurality of holes corresponding to the bearing supply path 10 and the communication hole portion 25. The front side portion 51 is a portion extending from the fixed portion 55 to the front side of the rotating shaft 1. The rear side portion 52 is a portion extending from the fixed portion 55 to the rear side of the rotating shaft 1. The front side portion 51 and the rear side portion 52 have a tubular shape. The thickness of the front side portion 51 and the rear side portion 52 in the radial direction is thinner than the thickness of the fixed portion 55 in the radial direction.

As shown in FIGS. 1 and 2, the damper ring 50 is formed with at least one or more grooves on the surface of the bearing portion 2 side (inner peripheral side) in the radial direction. In the present embodiment, the groove 33 is formed on the inner peripheral side surface of the rear side portion 52. Further, a groove 34 is formed on the inner peripheral side surface of the front side portion 51.

Each of the grooves 33 and 34 is an annular groove formed on the surface of the damper ring 50 so as to orbit around the rotation center axis of the rotation shaft 1. As shown in FIGS. 1 and 2, an O-ring 24 is engaged with each of the grooves 33 and 34.

The O-ring 24 engaged with each of the groove 33 and the groove 34 has a cross-sectional diameter longer than the depth of each of the groove 33 and the groove 34, and comes into contact with the outer peripheral surface 3a of the housing 3. As a result, a gap 44 is formed between the damper ring 50 and the housing 3 by the O-ring 24 engaged with each of the groove 33 and the groove 34. The damper ring 50 and the housing 3 do not come into direct contact with each other due to the presence of the gap 44.

The bearing unit (rotating shaft 1, bearing portion 2, etc.) is held by the O-ring 24 engaged with each of the groove 33 and the groove 34 with respect to the cover member 5 via the damper ring 50.

The O-ring 24 is an elastic member. When the air turbine drive spindle 200 operates, vibration is generated due to the swinging of the rotating shaft 1 on which the cup 80 is mounted on the tip end side. When vibration is transmitted to the O-ring 24 that engages with each of the grooves 33 and 34, the O-ring is deformed due to its elasticity. The O-ring 24 can absorb vibration by being deformed. As described above, the O-ring 24 has damping performance.

Further, in the damper ring 50, the thickness of the front side portion 51 and the rear side portion 52 is thinner than the thickness of the fixing portion 55, and the front side portion 51 and the rear side portion 52 are relative to the fixing portion 55. It can be displaced to. Therefore, the front side portion 51 and the rear side portion 52 are displaced with respect to the fixed portion 55, so that the vibration of the rotating shaft 1 and the like can be absorbed and attenuated. As the material constituting the damper ring 50, a metal such as stainless steel may be used, or a resin may be used. It is also conceivable that the material of the damper ring 50 is a material having a smaller Young's modulus. For example, aluminum may be used instead of stainless steel. Further, the material of the damper ring 50 may not be changed, and the front side portion 51 and the rear side portion 52 may be made thinner to facilitate deformation and easily attenuate vibration.

<Operation of air turbine drive spindle>
Next, the operation of the air turbine drive spindle 200 according to the present embodiment will be described.

When the air turbine drive spindle 200 operates, the drive gas is supplied from the drive gas air supply port 12 to the drive air supply nozzle 14 through the drive air supply path 13. The driving gas supplied to the driving air supply nozzle 14 is directed toward the rotary blade 15 of the thrust plate portion 1c of the rotating shaft 1 along a direction substantially parallel to the tangential direction (rotation direction) of the thrust plate portion 1c. It is spouted. The rotary blade 15 receives the ejected driving gas at the rear curved surface portion. At this time, the driving gas ejected to the rotor 15 reaches the outer peripheral side of the rear curved surface portion, is changed in direction by flowing along the rear curved surface portion, and is external from the exhaust hole 11 via the exhaust space 20. Is exhausted to. The reaction force of the force applied to the driving gas acts on the rotary blade 15, and the thrust plate portion 1c of the rotary shaft 1 is given a rotational torque. As a result, the rotation shaft 1 rotates along the rotation direction. The rotation speed of the rotating shaft 1 can be, for example, tens of thousands of rpm or more. Therefore, the air turbine drive spindle 200 is suitable for, for example, a spindle for an electrostatic coating machine.

<Effect>
The air turbine drive spindle 200 according to the present invention includes a rotating shaft 1, a bearing portion 2, a damper ring 50 as a support member, a cover member 5, and at least one or more O-rings 24. The bearing portion 2 surrounds at least a part of the outer peripheral surface of the rotating shaft 1. The damper ring 50 is arranged on the outer peripheral side of the bearing portion 2. The cover member 5 is arranged on the outer peripheral side of the damper ring 50, and houses the rotating shaft 1, the bearing portion 2, and the damper ring 50. A part of the damper ring 50 (fixing portion 55) is fixed to either the bearing portion 2 or the cover member 5 (cover member 5 in FIGS. 1 and 2). At least one or more O-rings 24 are in the thrust direction of the rotating shaft 1 in the gap 44 between the damper ring 50 and any one of the bearing portion 2 and the cover member 5 (bearing portion 2 in FIGS. 1 and 2). It is arranged at a position (front side portion 51 and rear side portion 52) that does not overlap with the above-mentioned part (fixed portion 55) of the damper ring 50.

In this way, the vibration of the rotating shaft 1 is absorbed or damped by the O-ring 24, and the front side portion 51 and the rear side portion 52 of the damper ring 50 are displaced (elastically deformed) to be absorbed or damped. Can be done. Therefore, the rotating shaft 1 can be stably rotated at high speed.

In the air turbine drive spindle 200, the material constituting the damper ring 50 may contain a metal or a resin. If the front side portion 51 and the rear side portion 52 of the damper ring 50 can be elastically deformed, the above-mentioned material can be selected and used in consideration of the usage environment of the spindle 200 and the like.

(Embodiment 2)
<Structure of air turbine drive spindle>
The air turbine drive spindle according to the second embodiment will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view for explaining the air turbine drive spindle according to the second embodiment, and shows the upper half of the air turbine drive spindle.

The air turbine drive spindle shown in FIG. 3 basically has the same configuration as the air turbine drive spindle shown in FIGS. 1 and 2, but is shown in FIG. 1 between the damper ring 50 and the housing 3. In addition to the O-ring 24, the third and fourth O-rings and an additional O-ring 24 are provided.

Specifically, as shown in FIG. 3, grooves 31 and 32 are formed in the region between the groove 33 and the groove 34 on the inner peripheral surface (the surface facing the housing 3) of the damper ring 50. The groove 31 and the groove 32 are arranged so as to sandwich the communication hole portion 25 in the thrust direction. The groove 31 and the groove 32 are annular grooves formed on the inner peripheral surface of the damper ring 50 so as to orbit around the rotation center axis of the rotation shaft 1. The additional O-ring 24 is located inside the grooves 31 and 32. The additional O-ring 24 is in contact with the inner peripheral surfaces of the grooves 31 and 32 and the surface of the housing 3.

<Effect>
In the air turbine drive spindle, the communication hole 25 (see FIG. 1) connected to the gap 44 (see FIG. 1) in which the O-ring 24 is arranged in at least one of the cover member 5 and the damper ring 50 (damper ring 50 in FIG. 3) (See FIG. 1) is formed. The air turbine drive spindle includes a supply unit 100 that supplies gas to the communication hole portion 25, and a plurality of sealing O-rings (O-rings 24 arranged in the grooves 31 and 32). The O-rings 24 arranged in the grooves 31 and 32 as the plurality of sealing O-rings are arranged in the gap 44 so as to sandwich the communication hole portion 25 in the thrust direction of the rotating shaft 1. The one or more O-rings arranged in the gap 44 include a plurality of damper O-rings (O-rings arranged in the grooves 33, 34). The O-rings arranged in the grooves 33 and 34 as the plurality of damper O-rings are arranged so as to sandwich the O-rings 24 arranged in the grooves 31 and 32 in the thrust direction of the rotating shaft 1.

The O-rings 24 arranged in the grooves 31 and 32 located relatively close to the communication hole portion 25 in this way are used as the sealing O-rings. The O-rings 24 arranged in the grooves 31 and 32 also have damping performance against vibration. Then, the O-ring 24 arranged in the grooves 33 and 34 located relatively far from the communication hole portion 25 is used as an O-ring for a damper whose main characteristic is damping performance.

Here, the source of vibration is mainly the cup 80 (see FIG. 1) fixed to the tip of the rotating shaft 1. In the structure of FIG. 3, since the O-rings 24 arranged in the grooves 31 and 32 are installed near the center of gravity of the rotating shaft 1 as sealing O-rings, vibration is generated by the precession motion centered on the O-rings 24. Can occur.

At the position of the sealing O-ring, the main function of the O-ring 24 is to seal the compressed air flowing from the communication hole 25 into the gap 44 (see FIG. 1) rather than damping the vibration. On the other hand, the outer damper O-rings (O-rings 24 arranged in the grooves 33 and 34) support the portion where the kinetic energy of the precession motion is large, and therefore play a large role as a damper O-ring for damping vibration. .. Further, since the compressed air is sealed by the O-rings 24 arranged in the grooves 31 and 32 described above, the O-rings 24 arranged in the grooves 33 and 34 receive almost no stress due to the compressed air. By dividing the roles of the O-rings 24 in this way, sufficient damping performance can be exhibited for the damper O-rings. Further, since the damper O-ring 24 blocks the outside air, the seal O-ring does not come into contact with the atmosphere of the outside air. Therefore, the type of material of the O-rings 24 arranged in the grooves 31 and 32, which are the O-rings for sealing, can be freely selected without considering the solvent resistance. For example, as the material of the O-ring 24 arranged in the grooves 31 and 32, a general material such as nitrile rubber or fluororubber can be used. On the other hand, as for the material of the O-ring 24 arranged in the grooves 33 and 34 as the O-ring for the damper, a perfluoroelastomer can be used in consideration of, for example, solvent resistance. As described above, the material constituting the plurality of sealing O-rings (O-rings 24 arranged in the grooves 31 and 32) constitutes a plurality of damper O-rings (O-rings 24 arranged in the grooves 33 and 34). It may be different from the material to be used.

(Embodiment 3)
<Structure of air turbine drive spindle>
The air turbine drive spindle according to the third embodiment will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view for explaining the air turbine drive spindle according to the third embodiment, and shows the upper half of the air turbine drive spindle.

The air turbine drive spindle shown in FIG. 4 basically has the same configuration as the air turbine drive spindle shown in FIG. 3, but the arrangement of the four O-rings 24 is different from the configuration shown in FIG. Differently, it is arranged in the gap between the damper ring 50 and the cover member 5. Grooves 31 to 34 are formed on the outer peripheral surface of the damper ring 50 (the surface facing the cover member 5). The arrangement of the grooves 31 to 34 in the thrust direction is the same as the arrangement of the grooves 31 to 34 in the spindle shown in FIG. The fixing surface 55a of the fixing portion 55 of the damper ring 50 is fixed to the housing 3. Since the fixed surface 55a is in close contact with the surface of the housing 3, the holes formed in the housing 3 forming the bearing supply path 10 and the holes formed in the damper ring 50 are airtightly connected.

<Effect>
As described above, even when the member to which the fixing portion 55 which is a part of the damper ring 50 is fixed is not the cover member 5 but the housing 3, the same effect as that of the air turbine drive spindle shown in FIG. 3 can be obtained. it can.

(Embodiment 4)
<Structure of air turbine drive spindle>
The air turbine drive spindle according to the fourth embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a schematic cross-sectional view for explaining the air turbine drive spindle according to the fourth embodiment, and shows the upper half of the air turbine drive spindle. FIG. 6 is a schematic perspective view showing the entire damper ring 50.

The air turbine drive spindle shown in FIGS. 5 and 6 basically has the same configuration as the air turbine drive spindle shown in FIG. 3, but in the damper ring 50 as a support member, the thrust direction of the rotating shaft 1 It is different from the spindle shown in FIG. 3 in that notches 53 and 54 are formed at the end portion of the above.

As shown in FIG. 6, the damper ring 50 is an annular member formed so as to surround the bearing portion 2 (see FIG. 5). The front side portion 51 of the damper ring 50 is formed with a notch 53 at the front end portion in the thrust direction. Further, the rear portion 52 of the damper ring 50 is formed with a notch 54 at the rear end portion in the thrust direction. The grooves 33 and 34 are formed so as to intersect the notches 53 and 54. That is, the O-rings 24 arranged in the grooves 33 and 34 are arranged so as to come into contact with the portions where the cuts 53 and 54 are formed in the damper ring 50.

<Effect>
By forming the cuts 53 and 34 in the front side portion 51 and the rear side portion 52 of the damper ring 50 in this way, the rigidity of the front side portion 51 and the rear side portion 52 can be reduced to facilitate deformation. As a result, the vibration damping performance of the damper ring 50 can be improved.

(Embodiment 5)
<Structure of air turbine drive spindle>
The air turbine drive spindle according to the fifth embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic cross-sectional view for explaining the air turbine drive spindle according to the fifth embodiment, and shows the upper half of the air turbine drive spindle.

The air turbine drive spindle shown in FIG. 7 basically has the same configuration as the air turbine drive spindle shown in FIG. 6, but the O-ring shown in FIG. 7 is located between the damper ring 50 and the cover member 5. The difference is that in addition to the ring 24, additional O-rings 24 are provided with the fifth and sixth rings.

Specifically, as shown in FIG. 7, grooves 35 and 36 are formed in a region between the groove 33 and the groove 34 on the outer peripheral surface (the surface facing the cover member 5) of the damper ring 50. The groove 35 and the groove 36 are arranged so as to sandwich the communication hole portion 25 in the thrust direction. The groove 35 is arranged between the groove 33 and the groove 31 in the thrust direction. The groove 36 is arranged between the groove 34 and the groove 32 in the thrust direction. The groove 35 and the groove 36 are annular grooves formed on the outer peripheral surface of the damper ring 50 so as to orbit around the rotation center axis of the rotation shaft 1. The additional O-ring 24 is located inside the grooves 35, 36. The additional O-ring 24 is in contact with the inner peripheral surfaces of the grooves 35 and 36 and the surface of the cover member 5. The grooves 35 and 36 are formed so as to intersect the notches 53 and 54.

<Effect>
According to such a configuration, the same effect as that of the spindle shown in FIG. 6 can be obtained, and the vibration damping performance can be further improved. That is, when the damper ring 50 is thinned or slitted to form notches 53 and 54, the damper ring 50 itself is deformed to damp the vibration. However, if a continuous load in the radial direction is generated instead of vibration, the damper ring 50 may be significantly deformed in one direction. If the damper ring 50 is significantly deformed, the damper ring 50 may come into contact with other parts, resulting in a sudden increase in vibration. In order to suppress this, the O-ring 24 as an auxiliary O-ring arranged in the grooves 35 and 36 shown in FIG. 7 is effective. With such a configuration, vibration can be damped by the easily deformable damper ring 50, and large deformation in one direction of the damper ring 50 can be suppressed by the O-rings 24 arranged in the grooves 35 and 36 as auxiliary O-rings.

<Groove shape>
Next, with reference to FIGS. 8 and 9, the shapes of the grooves 31 to 36 of the air turbine drive spindle according to the above-described embodiment will be specifically described. FIG. 8 is a schematic cross-sectional view showing the groove 31 and the groove 32 according to the fifth embodiment. FIG. 9 is an enlarged schematic cross-sectional view of the groove 32 shown in FIG. 8 and 9 are schematic views for explaining the shapes of the groove 31 and the groove 32 in the second embodiment, and in order to simplify the explanation, they are upside down from FIG. 3 and the damper ring 50. The thickness and the distance between the grooves are different from the actual ones.

Further, although the shape of the groove 32 will be described here with reference to FIGS. 8 and 9, the groove 31 also has the same shape and produces the same effect. Further, the grooves 33 to 36 in each of the above-described embodiments may also have the same shapes as the grooves 31 and 32, and in this case, the same effects as those of the grooves 31 and 32 are produced.

As shown in FIGS. 8 and 9, the groove 32 includes a first side wall 32a, a second side wall 32b, a bottom 32c (bottom surface), and a chamfered portion 32d. The distance L1 from the communication hole portion 25 (specifically, the intersection P between the bearing supply path 10 and the gap 43) to the first side wall 32a is from the distance L2 from the communication hole portion 25 to the second side wall 32b. Is also long. In other words, the side wall on the downstream side of the flow of the bearing gas supplied by the supply unit 100 (see the arrow α in FIG. 9) is the first side wall 32a, and the side wall on the upstream side of the flow of the bearing gas is the second side wall. It becomes the side wall 32b of.

The height H5 from the bottom 32c to the upper end (top 32e) of the first side wall 32a is lower than the height H4 from the bottom 32c to the upper end of the second side wall 32b. In this way, in order to make the height H5 lower than the height H4, a chamfered portion 32d connected to the upper side of the first side wall 32a is formed. In the examples of FIGS. 8 and 9, the chamfered portion 32d is a tapered surface. The space A is formed by forming the tapered surface.

The distance H2 shown in FIG. 9 indicates a range (distance) in which the O-ring 24 is not in contact with other parts (front portion 51 of the damper ring 50) in the radial direction. In other words, the distance H2 is also the distance from the portion of the first side wall 32a closest to the outer peripheral surface 3a of the housing 3 (that is, the top 32e) to the outer peripheral surface 3a of the housing 3. The distance H3 indicates the distance from the bottom portion 32c to the outer peripheral surface 3a of the housing 3.

<Effect of groove shape>
The groove 31 and the groove 32 are arranged on the inner peripheral side (bearing portion 2 side) surface of the damper ring 50 so as to sandwich the communication hole portion 25 in the thrust direction. Since the communication hole portion 25 communicates with the gap 44 (see FIG. 1), the bearing gas supplied from the supply port 9 by the supply unit 100 flows into the gap 44 through the communication hole portion 25.

Specifically, the bearing gas supplied from the supply port 9 by the supply unit 100 passes through the bearing supply path 10 and reaches the communication hole portion 25. A part of the bearing gas flows into the gap 44 through the communication hole 25 and reaches the groove 31 and the groove 32. The bearing gas that has reached the groove 31 and the groove 32 pushes the O-ring 24 that engages with each of the groove 31 and the groove 32 in the direction of low pressure (the direction away from the bearing supply path 10). The O-ring 24 that engages with each of the groove 31 and the groove 32 is extruded by the bearing gas, so that the inner peripheral surface of the groove 31 and the groove 32 of the damper ring 50 and the outer peripheral surface 3a of the housing 3 are brought into close contact with each other. Block the flow path of the bearing gas.

In this way, the bearing gas supplied from the supply unit 100 stays in the gap 44 due to the presence of the O-ring 24 and does not leak to the outside. That is, the O-ring 24 arranged in the groove 31 and the groove 32 has a sealing performance.

Here, referring to FIGS. 10 to 13, in the reference example in which the shapes of the groove 31 and the groove 32 are different in the spindles shown in FIGS. 8 and 9, the gap formed between the housing 3 and the damper ring 50 is formed. A case where the bearing gas is supplied to 44 (see FIG. 1) will be described. FIG. 10 is a schematic cross-sectional view in the case where the bearing gas is not supplied in the 31 and the groove 32 of the air turbine drive spindle according to the reference example. FIG. 11 is an enlarged cross-sectional schematic view of the groove 32 according to the reference example shown in FIG. FIG. 12 is a schematic cross-sectional view when bearing gas is supplied in the grooves 31 and the grooves 32 of the air turbine drive spindle according to the reference example. FIG. 13 is an enlarged cross-sectional schematic view of the groove 32 according to the reference example shown in FIG. In addition, in FIGS. 10 to 13, the distance between the grooves and the like are different from the actual ones as in FIGS. 8 and 9 for the sake of simplification of the description. Further, the distance H1 shown in FIGS. 11 and 13 indicates a range in which the O-ring 24 is not in contact with another component (housing 3) in the radial direction. This range is the range in which the O-ring 24 has elastic force.

As shown in FIG. 11, the heights of both side walls 32a and 32b of the groove 32 with which the O-ring 24 is engaged are the same. Therefore, when the bearing gas is supplied from the supply unit 100 to the gap 43, the distance H1 is shown in FIGS. 11 and 13 in comparison with the air turbine drive spindle of the configuration shown in FIGS. 8 and 9. The amount of decrease is large. The amount of decrease in the distance H1 is "distance H1 when the bearing gas is not supplied to the gap 43 (see FIG. 11)" and "distance H1 when the bearing gas is supplied to the gap 43 (see FIG. 13)". It is the difference with. As described above, since the amount of decrease in the distance H1 is large, the distance H1 when the bearing gas shown in FIG. 13 is supplied becomes small, and as a result, the elastic stroke of the O-ring 24 becomes small. Therefore, in the configuration of the reference example, when the bearing gas is supplied from the supply unit 100, the damping performance is deteriorated as compared with the case where the bearing gas is not supplied.

On the other hand, in the air turbine drive spindle of the present embodiment having the groove structure shown in FIGS. 9 and 9, the height H5 of the side wall 32a is higher than the height H4 of the side wall 32b as shown in FIG. Low. Therefore, when the bearing gas is supplied from the supply unit 100, as shown in FIG. 9, it corresponds to the size of a part 24a constituting the elastic stroke of the O-ring 24 as compared with the air turbine drive spindle of the reference example. The distance H2 to be bearing can be made larger than the distance H1 (see FIG. 13). That is, the amount of decrease in the distance H2 can be reduced. Here, the amount of decrease in the distance H2 is the difference between the "distance H2 when the bearing gas is not supplied to the gap 43" and the "distance H2 when the bearing gas is supplied to the gap 43". .. As a result, the amount of reduction in the elastic stroke of the O-ring 24 can be reduced. Therefore, by adopting the groove structure shown in FIGS. 8 and 9, the damping of the air turbine drive spindle when the bearing gas is supplied. Deterioration of performance can be suppressed.

Further, the height H5 of the side wall 32a is preferably the radius of the cross section of the O-ring 24. As a result, when the bearing gas is supplied from the supply unit 100, deterioration of the damping performance of the air turbine drive spindle can be suppressed, and the O-ring 24 can be prevented from deviating from the groove 32.

<First modification>
The air turbine drive spindle according to the first modification will be described with reference to FIGS. 14 and 15. FIG. 14 is a schematic cross-sectional view showing a groove 331 and a groove 341 included in the air turbine drive spindle according to the first modification. FIG. 15 is an enlarged sectional schematic view of a groove 341 included in the air turbine drive spindle according to the first modification shown in FIG. Although the groove 341 will be described here with reference to FIGS. 14 and 15, the groove 331 also has the same shape and produces the same effect. Further, the grooves 33 to 36 in the embodiment may also have the same shape as the groove 331 and the groove 341 according to the first modification, and may produce the same effect. The air turbine drive spindle according to the first modification has the same configuration as that of the air turbine drive spindle according to the above-described embodiment, except for the configuration described below.

As shown in FIGS. 14 and 15, the groove 341 includes a first side wall 341a, a second side wall 341b, a bottom 341c (bottom surface), and a notch 341d. The difference between the groove 341 shown in FIGS. 14 and 15 and the groove 32 shown in FIGS. 8 and 9 is that the groove 32 shown in FIGS. 8 and 9 includes the chamfered portion 34d. The groove 341 shown in FIG. 15 is a point including a notch portion (step portion) 341d. As described above, the groove 341 includes a notch 341d extending above the first side wall 341a. By forming the notch portion 341d, the height H5 of the first side wall 341a becomes lower than the height H4 of the second side wall 341b. Further, the top portion 341e is formed by forming the notch portion 341d. The distance from the top portion 341e to the outer peripheral surface 3a of the housing 3 is defined as the distance H2.

Even with such a configuration, when the bearing gas is supplied to the gap 44, a part 24a of the O-ring 24 moves in a state of having elastic force without restraining the surface of the part 24a. Space B can be formed. Therefore, the air turbine drive spindle according to the first modification has the same effect as the air turbine drive spindle according to the present embodiment having the grooves having the structures shown in FIGS. 8 and 9.

<Second modification>
The air turbine drive spindle according to the second modification will be described with reference to FIGS. 16 and 17. FIG. 16 is a schematic cross-sectional view showing a groove 332 and a groove 342 included in the air turbine drive spindle according to the second modification. FIG. 17 is an enlarged sectional schematic view of a groove 342 included in the air turbine drive spindle according to the second modification shown in FIG. Although the groove 342 will be described here with reference to FIGS. 16 and 17, the groove 332 also has the same shape and produces the same effect. Further, the grooves 33 to 36 in the embodiment may also have the same shape as the groove 332 and the groove 342 according to the second modification, and may produce the same effect. The air turbine drive spindle according to the second modification has the same configuration as that of the air turbine drive spindle according to the above-described embodiment, except for the configuration described below.

As shown in FIGS. 16 and 17, the groove 342 includes a first side wall 342a, a second side wall 342b, and a bottom portion 342c (bottom surface). In the following, of the outer peripheral surface of the front side portion 51 of the damper ring 50, the region near the side wall 342a is referred to as the first region 3b, and the region near the second side wall 342b is referred to as the second region 3c. In the second modification, the shortest distance P1 between the first region 3b and the bottom portion 342c is shorter than the shortest distance P2 between the second region 3c and the bottom portion 342c. P1 = H5 and P2 = H4. Further, the distance from the top portion 342e to the outer peripheral surface 3a of the housing 3 is defined as the distance H2. The height H5 of the first side wall 342a is lower than the height H4 of the second side wall 342b.

Even with such a configuration, when the bearing gas is supplied to the gap 44, the space C in which a part 24a of the O-ring 24 moves in a state where the surface of the part 24a is not constrained and has an elastic force. Can be formed. Therefore, the air turbine drive spindle according to the second modification has the same effect as the air turbine drive spindle according to the present embodiment having the grooves having the structures shown in FIGS. 8 and 9.

<Third variant>
The air turbine drive spindle according to the third modification will be described with reference to FIGS. 18 and 19. FIG. 18 is a schematic cross-sectional view showing a groove 333 and a groove 343 included in the air turbine drive spindle according to the third modification. FIG. 19 is an enlarged sectional schematic view of a groove 343 included in the air turbine drive spindle according to the third modification shown in FIG. Although the groove 343 will be described here with reference to FIGS. 18 and 19, the groove 333 also has the same shape and produces the same effect. Further, the grooves 33 to 36 in the embodiment may also have the same shape as the groove 333 and the groove 343 according to the third modification, and may produce the same effect. The air turbine drive spindle according to the third modification has the same configuration as that of the air turbine drive spindle according to the above-described embodiment, except for the configuration described below.

As shown in FIGS. 18 and 19, the groove 343 includes a first side wall 343a, a second side wall 343b, a bottom 343c (bottom surface), and a chamfered portion 343d. The chamfered portion 32d of the groove shown in FIGS. 8 and 9 is assumed to be a tapered surface (flat surface), but the chamfered portion 343d of the third modified example has a curved surface shape as shown in FIG. Have. The chamfered portion 343d preferably has a shape that bulges outward. By forming the chamfered portion 343d, the top portion 343e is formed. The distance from the top portion 343e to the outer peripheral surface 3a of the housing 3 is defined as the distance H2.

Even with such a configuration, when the bearing gas is supplied to the gap between the housing 3 and the damper ring 50, the elastic force of a part 24a of the O-ring 24 is not constrained by the surface of the part 24a. It is possible to form a space D that moves while holding the. Therefore, the air turbine drive spindle according to the third modification has the same effect as the air turbine drive spindle according to the present embodiment having the grooves having the structures shown in FIGS. 8 and 9. The chamfered portion 343d may have a shape dented in one direction of the rotation axis.

<Crushing allowance>
The design of the crushing allowance of the O-ring 24 will be described. The crushing allowance is the compression distance of the O-ring 24 when the O-ring 24 is compressed while being mounted in the groove. For example, if the diameter of the cross section of the O-ring 24 in the uncompressed state is D and the diameter of the cross section of the O-ring 24 in the compressed state (for example, H3 shown in FIG. 9) is H, the crushing allowance X is obtained by subtracting H from D. It is represented by the value.

A specified value is set for the crushing allowance of the O-ring 24 according to the JIS standard and the manufacturer's specifications. For example, when the diameter of the cross section of the O-ring 24 is D = 2 mm, the lower limit of the specified value of the crushing allowance is set to X = 0.3 mm.

Here, in the case of the spindle according to the second to fifth embodiments, it is essential that the O-ring 24 that engages with each of the grooves 33 to 36 formed on the far side of the communication hole portion 25 has a sealing performance. Therefore, the crushing allowance may be smaller than the specified value.

For example, the crushing allowance may be less than X = 0.3 mm. Further, the crushing allowance may be X = 0 mm. In this case, the O-ring 24 that engages the groove comes into contact with the surface located on the upper side without compression. For example, the O-ring 24 that engages with the groove 33 in FIG. 3 comes into contact with the outer peripheral surface 3a of the housing 3 without compression. Further, the crushing allowance may be less than X = 0 mm, that is, negative. In this case, the O-ring 24 that engages the groove does not compress and does not come into contact with the surface located on the upper side. For example, the O-ring 24 that engages with the groove 33 of FIG. 3 may not be compressed and may not come into contact with the outer peripheral surface 3a of the housing 3.

However, when the crushing allowance is less than X = 0 mm, the diameter D of the cross section of the O-ring 24 is preferably longer than the depth of the engaging groove. That is, when the O-ring 24 is engaged with the groove, it is preferable that the O-ring 24 at least protrudes from the groove. If the O-ring 24 does not protrude from the groove, the O-ring 24 cannot contact the opposing member first when the vibration from the rotating shaft 1 is transmitted, so that the vibration cannot be attenuated well by the O-ring 24. is there.

In this way, the impact was received by setting the crushing allowance of the O-ring 24 engaged with each of the grooves 33 to 36 formed on the far side of the communication hole 25 to be less than 0.3 mm, which is shorter than the specified value. Since the amount of deformation that the O-ring 24 can sometimes deform can be made larger, the vibration from the rotating shaft 1 can be further damped by the elasticity of the O-ring 24 that engages with each of the grooves 31 to 34.

Although the embodiment of the present invention has been described above, it is possible to modify the above-described embodiment in various ways. Moreover, the scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by the scope of claims and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The present invention is particularly advantageously applied to an air turbine drive spindle used in electrostatic coating equipment and the like.

1 Rotating shaft, 1a, 3a outer peripheral surface, 1b shaft part, 1c thrust plate part, 2 bearing part, 3 housing, 3b first area, 3c second area, 4 bearing sleeve, 5 cover member, 6 nozzle plate, 7 journal Bearings, 8 thrust bearings, 9 supply ports, 10 bearing supply paths, 11 exhaust holes, 12 drive gas air supply ports, 13 drive air supply paths, 14 drive air supply nozzles, 15 rotary blades, 16 magnets, 17 Through hole, 18 rotation sensor insertion port, 20 exhaust space, 24 O ring, 24a part, 25 communication hole, 29 center of gravity, 31-36, 331, 332, 333, 341, 342, 343 groove, 32a, 341a, 342a , 343a first side wall, 32b, 341b, 342b, 343b second side wall, 32c, 341c, 342c, 343c bottom, 32d, 34d, 343d chamfer, 32e, 341e, 342e, 343e top, 41, 42, 43, 44 voids, 45 paint supply pipes, 50 damping, 51 front side parts, 52 rear side parts, 53, 54 notches, 55 fixed parts, 55a fixed surfaces, 80 cups, 100 supply parts, 200 air turbine drive spindles, 341d Notch.

Claims (8)

The axis of rotation and
A bearing portion that surrounds at least a part of the outer peripheral surface of the rotating shaft,
A support member arranged on the outer peripheral side of the bearing portion and
It is arranged on the outer peripheral side of the support member, and includes the rotating shaft, the bearing portion, and a cover member for accommodating the support member.
A part of the support member is fixed to either the bearing portion or the cover member, and further
At least one or more arranged at a position not overlapping with the part of the support member in the thrust direction of the rotation shaft in the gap between the support member and the bearing portion and any other of the cover members. Equipped with an O-ring
An air turbine drive spindle in which a portion of the support member on which the O-ring is arranged and one of the bearing portion and the cover member are arranged at intervals in the radial direction of the rotation shaft . The air turbine drive spindle according to claim 1, wherein the material constituting the support member includes metal. The air turbine drive spindle according to claim 1, wherein the material constituting the support member contains a resin. The support member is an annular member formed so as to surround the bearing portion.
The air turbine drive spindle according to any one of claims 1 to 3, wherein a notch is formed at an end portion of the support member in the thrust direction of the rotating shaft. The air turbine drive spindle according to claim 4, wherein the O-ring includes a first O-ring arranged so as to contact a portion of the support member in which the notch is formed. A communication hole portion connected to the gap is formed in at least one of the cover member and the support member.
A supply unit that supplies gas to the communication hole and
A plurality of sealing O-rings arranged in the gap so as to sandwich the communication hole portion in the thrust direction of the rotation shaft are provided.
The O-ring according to any one of claims 1 to 5, wherein the O-ring includes a plurality of damper O-rings arranged so as to sandwich the plurality of sealing O-rings in the thrust direction of the rotating shaft. Air turbine drive spindle. The air turbine drive spindle according to claim 6, wherein the material constituting the plurality of sealing O-rings is different from the material constituting the plurality of damper O-rings. The air turbine drive spindle according to claim 6 or 7, wherein the crushing allowance of the plurality of damper O-rings is less than 0.3 mm.