JP6804294B2 - Aerostatic bearing equipment - Google Patents

Description

The present invention relates to an aerostatic bearing device, and more particularly to an aerostatic bearing device including a bearing body having an axial throttle hole and a radial throttle hole.

Conventionally, an aerostatic bearing device including a bearing body having an axial throttle hole and a radial throttle hole is known (see, for example, Patent Document 1).

Patent Document 1 discloses a device including a rotor (rotating body) including a shaft (spindle) and an air bearing (bearing body). The air bearings are arranged radially outside the shaft so as to surround the shaft. Further, the air bearing includes a passage for supplying air between the air bearing and the rotating body from the axial direction (axial direction) of the shaft, and the air bearing and the rotating body from the radial direction of the shaft (radial direction). It has the same number of separate passages for supplying air between the bearings.

Here, in the air bearing, the bearing rigidity has a great influence on the mechanical performance. Bearing rigidity is affected at least by the axial air pressure of the shaft (spindle) and the radial air pressure magnitude, throttle diameter and bearing clearance of the shaft.

Jikkenhei No. 5-10824

However, in Patent Document 1, since the number of passages for supplying air from the axial direction (axial direction) of the shaft and the passages for supplying air from the radial direction (radial direction) of the shaft are the same, the number of passages is axial. There is a problem that it is difficult to increase the air pressure in the direction to the air pressure in the radial direction to obtain a large bearing rigidity. Further, since the air bearing has a passage for supplying air from the axial direction of the shaft and a passage for supplying air from the radial direction of the shaft, the device configuration (passage structure) is complicated. There is a problem.

The present invention has been made to solve the above-mentioned problems, and one object of the present invention is that a large bearing rigidity can be easily obtained and the device configuration (passage structure) can be simplified. It is to provide an aerostatic bearing device.

The pneumatic bearing device according to one aspect of the present invention includes a rotating body including a spindle and a bearing body portion arranged radially outside the spindle so as to surround the spindle, and the bearing body is formed of the spindle. Axial drawing holes for supplying air between the bearing body and the rotating body from the axial direction, and radial drawing holes for supplying air between the bearing body and the rotating body from the radial direction of the spindle. a plurality of first air passage having bets, without a radial throttle bore, viewed contains a plurality of second air passage having an axial aperture hole, axial aperture hole, in the circumferential direction of the main shaft, the first gap The radial throttle holes are provided at a second interval different from the first interval in the circumferential direction of the main shaft .

In the aerostatic bearing device according to one aspect of the present invention, as described above, the bearing main body is provided with an axial drawing hole for supplying air between the bearing main body and the rotating body from the axial direction of the spindle. , A plurality of first air passages having a radial drawing hole for supplying air between the bearing body and the rotating body from the radial direction of the spindle, and an axial drawing hole without having the radial drawing hole. A plurality of second air passages to be provided are provided. As a result, the axial throttle hole and the radial throttle hole can be integrally provided in the first air passage, so that at least a part of the air passages can be shared. Therefore, the device configuration (passage structure) can be simplified. Further, since the bearing main body is provided with more axial throttle holes than the radial throttle holes, a large bearing rigidity can be easily obtained. Therefore, in the aerostatic bearing device, a large bearing rigidity can be easily obtained, and the device configuration (passage structure) can be simplified.

In the display device according to the above one aspect, preferably, the axial diaphragm holes are uniformly provided at the first interval on the entire circumference of the spindle, and the radial diaphragm holes are larger than the first spacing on the entire circumference of the spindle. It is evenly provided at two intervals. With this configuration, the axial throttle holes and the radial throttle holes are arranged in a well-balanced manner in the circumferential direction of the spindle, so that air can be supplied in a well-balanced manner between the spindle and the bearing body. As a result, the rotation of the spindle can be made more stable.

In the display device according to the above one aspect, preferably, the first air passage and the second air passage are alternately arranged one by one in the circumferential direction of the main shaft. With this configuration, the axial diaphragm holes and the radial diaphragm holes can be arranged in a more balanced manner in the circumferential direction of the spindle, so that the rotation of the spindle can be further stabilized.

In this case, preferably, the first air passage and the second air passage adjacent to each other are arranged at equal intervals as a whole. With this configuration, the air flow in the circumferential direction of the spindle can be made rotationally symmetric with respect to the central axis of the spindle, so that the rotation of the spindle can be further stabilized.

In the display device according to the above one aspect, preferably, the first air passage has a one-sided first air passage having an axial throttle hole and a radial throttle hole for supplying air to one side in the axial direction of the spindle, and the spindle. It has an axial throttle hole and a first air passage on the other side having a radial throttle hole for supplying air to the other side in the axial direction of the air, and air is separately provided in the first air passage on one side and the first air passage on the other side. Is further provided with an air supply unit capable of supplying air. With this configuration, the first air passage on one side and the first air passage on the other side can supply air to both sides in the axial direction in a well-balanced manner. As a result, the rotation of the spindle can be made more stable.

In this case, preferably, the rotating body is provided at one end in the axial direction of the spindle, and the first rotating surface to which air is supplied from the first air passage on one side to the bearing main body and the spindle. A second rotating surface provided at the other end in the axial direction and to which air is supplied from the other side first air passage to the bearing main body portion, and is provided by the air supply portion to the one side first air passage. By stopping the supply of air and continuing the supply of air to the first air passage on the other side by the air supply unit, the first rotating surface is brought into close contact with the bearing body and is clamped. It is configured. With this configuration, the air supply unit stops supplying air to the first air passage on one side, clamps the first rotating surface to the bearing body, and then to the first air passage on the other side. Can supply air. As a result, even in the clamped state, air can be continuously supplied between the bearing body and the spindle to the other side in the radial direction and the axial direction. As a result, galling (friction) between the bearing body and the spindle can be suppressed while strongly clamping the first rotating surface.

In the configuration in which the first rotating surface is clamped in close contact with the bearing body, the spindle preferably has a cylindrical shape, and the rotating body has a spindle from the bearing surface side of the bearing body on the first rotating surface side. A first ventilation space (bearing space, that is, a space that allows air to pass between the inside and the outside of the spindle) is included on the inner surface side of the cylinder. With this configuration, the first ventilation space facilitates air flow from the other side first air passage side to the first rotating surface side (one side first air passage side in a state where air is not supplied). Therefore, galling (friction) between the bearing body and the spindle can be further suppressed.

In the configuration in which the main shaft includes the first ventilation space, preferably, the bearing main body portion is fixedly attached, and a housing portion to which the rotating body is rotatably attached is further provided, and the housing portion is a shaft rather than the second rotating surface. At a position on the other side of the direction, an exhaust hole for exhausting air from the first ventilation space is included. Here, for example, when an exhaust hole is provided between the first air passage on one side and the first air passage on the other side to stop (clamp) the air supply to the first air passage on one side, the other The air from the side first air passage is discharged to the outside without passing through the first ventilation space. Therefore, the air from the first air passage on the other side is not supplied to a wide range between the spindle and the bearing main body, and galling is likely to occur. Therefore, by configuring as described above, the air from the first air passage on the other side can be guided to the first ventilation space, and the air from the first ventilation space can be exhausted through the exhaust hole. Therefore, the air from the other side first air passage side can be made easier to flow to the clamped first rotating surface side (one side first air passage side in the state where air is not supplied). As a result, galling (friction) between the bearing body and the spindle can be further suppressed.

In the configuration in which the spindle includes the first ventilation space, the first ventilation space is preferably formed in the vicinity of one end on the first rotating surface side of the spindle. With this configuration, the air that generates pressure in the radial direction from the first air passage side on the other side can be guided to the vicinity of one end on the first rotating surface side of the spindle, so that the radial direction can be used when clamping. It is possible to suppress the occurrence of misalignment of the bearing body and further suppress galling (friction) between the bearing body and the spindle.

In the configuration in which the rotating body includes the first ventilation space, the rotating body preferably includes a second ventilation space for passing air from the second rotation surface side of the bearing body portion to the inner surface side of the cylinder of the spindle, and the second The ventilation space is formed in the vicinity of the other end on the side opposite to the first ventilation space of the main shaft. With this configuration, air can be ventilated to the inside of the spindle from the vicinity of both ends in the axial direction of the spindle by the first ventilation space and the second ventilation space, respectively, so that the outer surface of the cylinder of the spindle can be ventilated. The air can be effectively spread throughout the area. As a result, it is possible to further suppress the occurrence of positional deviation in the radial direction during clamping, and further suppress galling (friction) between the bearing body and the spindle.

In the configuration in which the first rotating surface is clamped in close contact with the bearing body, the rotating body preferably has a flat plate-shaped first rotating table having a first rotating surface and a flat plate shape having a second rotating surface. Includes a second rotating table. With this configuration, the rotating body can effectively receive the axial air and the radial air from the bearing main body portion by the first rotary table, the second rotary table, and the spindle.

According to the present invention, as described above, it is possible to provide an aerostatic bearing device capable of easily obtaining a large bearing rigidity and simplifying the device configuration (passage structure).

It is sectional drawing which showed the whole structure of the aerostatic bearing apparatus by 1st Embodiment of this invention. It is sectional drawing which showed the bearing bush of the aerostatic bearing apparatus by 1st Embodiment of this invention. It is a figure which looked at the bearing bush of the aerostatic bearing apparatus by 1st Embodiment of this invention from the A1 direction side. It is a figure which looked at the bearing bush of the aerostatic bearing apparatus by 1st Embodiment of this invention from the A2 direction side. It is sectional drawing which showed the whole structure of the aerostatic bearing apparatus by 2nd Embodiment of this invention. It is a figure for demonstrating the air flow of the aerostatic bearing apparatus according to 2nd Embodiment of this invention. It is a figure for demonstrating the flow of the air in the clamp state of the aerostatic bearing apparatus by 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
The configuration of the aerostatic bearing device 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

(Composition of pneumatic bearing device)
As shown in FIG. 1, the aerostatic bearing device 100 according to the first embodiment of the present invention includes a housing portion 1, a bearing bush 2, an air supply portion 3a and 3b, a rotating body 4, a motor 5, and an encoder. It is equipped with 6. The rotating body 4 includes a spindle 40, a first rotating table 41, and a second rotating table 42. In the following description, the axial direction (axial direction) of the main shaft 40 is the A direction (vertical direction, the A1 direction is the upward direction, and the A2 direction is the downward direction), and the radial direction of the main shaft 40 is the B direction. , The circumferential direction of the main shaft 40 will be described as the C direction. The bearing bush 2 is an example of a "bearing body" within the scope of the claims.

The aerostatic bearing device 100 can rotate the rotating body 4 at high speed, for example, and is used for a bearing portion of a lathe or a milling machine. Further, the aerostatic bearing device 100 can rotate the rotating body 4 by a predetermined angle, and is used as a turntable for installing the work piece when processing the work piece installed on the rotating body 4. Will be done.

(Structure of housing)
The housing portion 1 includes an installation housing portion (base portion) 10 and an air supply housing portion 11. Further, the housing portion 1 generally has a rotating body shape obtained by rotating it with respect to the central axis α of the main shaft 40.

The installation housing portion 10 is a portion that supports each configuration of the aerostatic bearing device 100, and is a portion (member) that is installed with bolts or the like on the installation surface. Further, the installation housing portion 10 includes a cylindrical portion 110 on the inside (B2 direction side) and a flat portion (B1 direction side) extending from one end (A2 direction side end portion) of the cylindrical portion 110 to the outside (B1 direction side). It is composed of 111 and the part to be installed). Further, an air supply housing portion 11, a motor 5, and an encoder 6 are attached to the installation housing portion 10.

The air supply housing portion 11 has a cylindrical shape. Further, the air supply housing portion 11 is made of metal. Further, the air supply housing portion 11 is fixed to the installation housing portion 10 by bolts or the like. Further, the air supply housing portion 11 constitutes an outer peripheral side surface in the aerostatic bearing device 100 in the B direction.

The air supply housing portion 11 has air passages 11a and 11b that penetrate from the outer surface to the inner surface and are paths for supplying air to the bearing bush 2. Both the air passages 11a and 11b extend in the B direction. Further, the air passages 11a and 11b are provided in two rows with a predetermined interval in the A direction. The air passage 11a is arranged on the A1 direction side of the air passage 11b. Further, 24 air passages 11a and 11b are provided at equal intervals in the C direction (on the entire circumference at a pitch of 15 degrees).

(Bearing bush)
The bearing bush 2 has a cylindrical shape. Further, the bearing bush 2 is made of metal. Further, the bearing bush 2 is fitted inside the air supply housing portion 11 by shrink fitting and cooling fitting (with the air supply housing portion 11 heated and the bearing bush 2 cooled). That is, the bearing bush 2 is fixedly attached to the air supply housing portion 11. Further, the bearing bush 2 is arranged on the B1 direction side (outside in the radial direction) of the spindle 40 so as to surround the spindle 40.

The bearing bush 2 includes a plurality of first air passages having an axial throttle hole, a plurality of first air passages having a radial throttle hole, and a plurality of second air passages 23 having an axial throttle hole without having a radial throttle hole. .. The first air passage includes a first air passage 20 on one side and a first air passage 21 on the other side. Further, as shown in FIG. 2, the bearing bush 2 has an air supply surface 120 located on the A1 direction side, an air supply surface 121 located on the A2 direction side, and an air supply surface 122 located on the B2 direction side. Have. A1 direction side ends of axial throttle holes 20a and 22a, which will be described later, are connected to the air supply surface 120. Further, the air supply surface 121 is connected to the A2 direction side ends of the axial throttle holes 21a and 23a, which will be described later. Further, the air supply surface 122 is connected to the inner (B2 direction side) end portions of the radial throttle holes 20b and 21b, which will be described later.

As shown in FIG. 1, the first air passage 20 and the second air passage 22 on one side are provided on the A1 direction side of the bearing bush 2. The first air passage 21 and the second air passage 23 on the other side are provided on the A2 direction side of the bearing bush 2.

As shown in FIG. 3, the one-sided first air passage 20 and the other-side first air passage 21 are arranged at positions overlapping each other when viewed from the A direction. That is, the positions of the first air passage 20 on one side and the first air passage 21 on the other side are the same in the circumferential direction (C direction). Further, the second air passages 22 and 23 are arranged at positions overlapping each other when viewed from the A direction. That is, the positions of the second air passages 22 and 23 in the circumferential direction (C direction) are the same.

The first air passage 20 and the second air passage 22 on one side are alternately arranged one by one in the circumferential direction (C direction) of the main shaft 40. The first air passage 20 and the second air passage 22 on one side adjacent to each other are arranged at equal intervals (15 degree pitch interval).

As shown in FIG. 4, the first air passage 21 and the second air passage 23 on the other side are alternately arranged one by one in the circumferential direction (C direction) of the main shaft 40. Further, the other side first air passage 21 and the second air passage 23 adjacent to each other are arranged at equal intervals (15 degree pitch interval).

As shown in FIG. 1, the first air passage 20 on one side is between the bearing bush 2 and the rotating body 4 (first rotary table 41) from the axial direction of the main shaft 40 and in the axial direction of the main shaft 40. On one side (A1 direction side), an axial throttle hole 20a and a radial throttle hole 20b for supplying air are provided. The axial throttle hole 20a extends in the A direction so that air can be supplied (discharged) in the A1 direction. The radial throttle hole 20b extends in the B direction so that air can be supplied (discharged) in the B2 direction. As shown in FIG. 2, the axial throttle hole 20a is configured to supply (discharge) air from the air supply surface 120. The radial throttle hole 20b is configured to supply (discharge) air from the air supply surface 122.

Both the axial diaphragm hole 20a and the radial diaphragm hole 20b are self-made diaphragm holes. The self-made throttle hole means a small diameter throttle hole formed directly in the air bearing member. The axial throttle hole 20a and the radial throttle hole 20b may be other throttle holes such as an orifice throttle hole other than the self-made throttle hole. The orifice throttle hole means a throttle hole having a small diameter formed by mounting an orifice in the throttle hole formed in the air bearing member.

As shown in FIG. 1, the axial throttle hole 20a is a hole for supplying air between the surface of the bearing bush 2 on the A1 direction side and the first rotary table 41 (air supply surface 41a described later). is there. Further, the radial throttle hole 20b is a hole for supplying air between the inner side surface (the surface on the B2 direction side) of the bearing bush 2 and the spindle 40. The air-supplied surface 41a is an example of the "first rotating surface" in the claims.

The first air passage 21 on the other side is between the bearing bush 2 and the rotating body 4 (second turntable 42) from the axial direction of the main shaft 40, and on the other side (A2 direction side) of the main shaft 40 in the axial direction. Has an axial throttle hole 21a and a radial throttle hole 21b for supplying air. The axial throttle hole 21a extends in the A direction so that air can be supplied (discharged) in the A2 direction. The radial throttle hole 21b extends in the B direction so that air can be supplied (discharged) in the B2 direction. As shown in FIG. 2, the axial throttle hole 21a is configured to supply (discharge) air from the air supply surface 121. The radial throttle hole 21b is configured to supply (discharge) air from the air supply surface 122. Both the axial diaphragm hole 21a and the radial diaphragm hole 21b are self-made diaphragm holes.

As shown in FIG. 1, the axial throttle hole 21a is a hole for supplying air between the surface of the bearing bush 2 on the A2 direction side and the second rotary table 42 (air supply surface 42a described later). is there. Further, the radial throttle hole 20b is a hole for supplying air between the inner side surface (the surface on the B2 direction side) of the bearing bush 2 and the spindle 40. The air-supplied surface 42a is an example of the "second rotating surface" in the claims.

The second air passage 22 does not have a radial throttle hole, but has an axial throttle hole 22a for supplying air between the bearing bush 2 and the first rotary table 41. The axial throttle hole 22a is configured to supply (discharge) air from the air supply surface 120. As shown in FIG. 1, the axial throttle hole 22a extends in the A direction so that air can be supplied (discharged) in the A1 direction. The axial diaphragm hole 22a is a self-made diaphragm hole.

Further, the second air passage 23 does not have a radial throttle hole, but has an axial throttle hole 23a for supplying air between the bearing bush 2 and the second rotary table 42. The axial throttle hole 23a extends in the A direction so that air can be supplied (discharged) in the A2 direction. The axial throttle hole 23a is configured to supply (discharge) air from the air supply surface 121. The axial diaphragm hole 23a is a self-made diaphragm hole.

As shown in FIG. 3, the axial diaphragm holes 20a and 22a on the A1 direction side are evenly provided on the entire circumference of the main shaft 40 on the A1 direction side at intervals of 15 degrees. Specifically, the axial throttle holes 20a and 22a on the A1 direction side are alternately provided one by one at intervals of 15 degrees on the entire circumference of the main shaft 40.

As shown in FIG. 4, the axial diaphragm holes 21a and 23a on the A2 direction side are evenly provided on the entire circumference of the main shaft 40 on the A2 direction side at intervals of 15 degrees. Specifically, the axial throttle holes 21a and 23a on the A2 direction side are alternately provided one by one at intervals of 15 degrees on the entire circumference of the main shaft 40.

As shown in FIG. 3, the radial diaphragm holes 20b on the A1 direction side have a 30-degree pitch interval larger than the intervals (15-degree pitch intervals) provided on the axial diaphragm holes 20a and 22a on the A1 direction side, and the entire spindle 40. It is evenly distributed around the circumference.

As shown in FIG. 4, the radial diaphragm holes 21b on the A2 direction side have a 30-degree pitch interval larger than the intervals (15-degree pitch intervals) provided on the axial diaphragm holes 21a and 23a on the A2 direction side, and all of the spindle 40. It is evenly distributed around the circumference.

(Air supply unit)
As shown in FIG. 1, the air supply unit 3a has the first air passage 20 and the second air passage 20 on one side from the outside of the bearing bush 2 in the B direction via the air passage 11a on the A1 direction side of the air supply housing portion 11. It is configured to be able to supply air to the air passage 22.

The air supply unit 3b is arranged on the A2 direction side of the air supply unit 3a. Further, the air supply unit 3b is provided with air from the outside of the bearing bush 2 in the B direction to the first air passage 21 and the second air passage 23 on the other side via the air passage 11b on the A2 direction side of the air supply housing portion 11. Is configured to be able to supply.

Further, the air supply unit 3a and the air supply unit 3b are configured to be able to separately supply air to the bearing bush 2 and stop the air supply.

The surface of the bearing bush 2 on the first turntable 41 side (A1 direction side) is lap-finished.

(Rotating body)
As shown in FIG. 1, the rotating body 4 has its own weight due to the air (air pressure) supplied through the first air passage 20 on one side of the bearing bush 2, the first air passage 21 on the other side, and the second air passages 22 and 23. Is held and is configured to be held at a position (floating state) away from other configurations of the pneumatic bearing device 100.

The spindle 40 has a cylindrical shape. Inside the main shaft 40, a cylindrical portion 111 of the housing portion (base portion) 10 for installation of the housing portion 1 is arranged. The spindle 40 is arranged at a predetermined interval so as not to come into contact with the housing portion 1.

The first rotary table 41 is provided on the A1 direction side of the main shaft 40. Further, the first rotary table 41 has a circular flat plate shape. Further, the first rotary table 41 has an air supply surface 41a on the spindle side (A2 direction side) and an installation surface 41b on the opposite side (A1 direction side) from the spindle side. The air supply surface 41a is a surface on which air is supplied from the first air passage 20 and the second air passage 22 on one side to the bearing bush 2. The air supply surface 41a is arranged to face the wrapped air supply surface 120 of the bearing bush 2. The installation surface 41b is, for example, a surface on which a workpiece or the like is installed.

The second turntable 42 is provided at the other end of the spindle 40 (the end on the A2 direction side). Further, the second turntable 42 has an annular shape having an outer diameter smaller than that of the first turntable 41. Further, the second rotary table 42 has an air supply surface 42a. The air supply surface 42a is provided at the other end of the spindle 40 (the end on the A2 direction side), and air is supplied from the other side first air passage 21 and the second air passage 23 to the bearing bush 2. It is the surface to be done. Further, the air supply surface 42a is arranged so as to face the air supply surface 121 of the bearing bush 2.

The air supply surface 41a is wrapped. The supply of air to the first air passage 20 and the second air passage 22 on one side by the air supply unit 3a is stopped, and the air to the first air passage 21 and the second air passage 23 on the other side by the air supply unit 3b is stopped. The air-supplied surface 41a (first turntable 41) is brought into close contact with the bearing bush 2 (the surface on the A1 direction side) and clamped (the first turntable 41 is a bearing). It is configured to be closely fixed to the bush 2).

(Motor and encoder)
As shown in FIG. 1, the motor 5 is arranged inside the housing portion 10 for installation and the spindle 40 of the housing portion 1. That is, the motor 5 is a so-called built-in motor incorporated inside the spindle system. Further, the motor 5 includes a stator 50 and a rotor 51. The stator 50 is attached to the inner surface of the housing portion 10 for installation of the housing portion 1. Further, the rotor 51 is connected to the first rotary table 41, and is configured to apply torque around the central axis α to the first rotary table 41 by rotation.

The encoder 6 is configured to be able to acquire the rotation angle of the rotor 51. The aerostatic bearing device 100 is provided with a drive control unit (not shown) that controls the drive of the motor 5, and the drive control unit drives (rotates) the motor 5 based on the acquired value of the encoder 6. It is configured to control the rotation of the body 4.

(Effect of the first embodiment)
In the first embodiment, the following effects can be obtained.

In the first embodiment, as described above, the axial throttle holes 20a and 21a for supplying air between the bearing bush 2 and the rotating body 4 from the axial direction of the spindle 40 and the spindle 40 are provided to the bearing bush 2. It has a plurality of first air passages (20, 21) having radial throttle holes 20b, 21b for supplying air between the bearing bush 2 and the rotating body 4 from the radial direction of the above, and radial throttle holes. Instead, a plurality of second air passages 22 and 23 having axial throttle holes 22a and 23a are provided. As a result, the axial throttle holes 20a and 21a and the radial throttle holes 20b and 21b can be integrally provided in the first air passages (20, 21), so that at least a part of the air passages can be shared. it can. Therefore, the device configuration (passage structure) can be simplified. Further, since the bearing bush 2 is provided with more axial throttle holes 20a, 21a, 22a, 23a than the radial throttle holes 20b, 21b, a large bearing rigidity can be easily obtained. Therefore, in the aerostatic bearing device 100, a large bearing rigidity can be easily obtained, and the device configuration (passage structure) can be simplified.

Further, in the first embodiment, as described above, the axial diaphragm holes 20a, 21a, 22a, 23a are evenly provided on the entire circumference of the spindle 40 at the first interval, and the radial diaphragm holes 20b, 21b are provided on the spindle 40. A second interval (30 degree pitch interval) larger than the first interval (15 degree pitch interval) is evenly provided on the entire circumference. As a result, the axial throttle holes 20a, 21a, 22a, 23a and the radial throttle holes 20b, 21b are arranged in a well-balanced manner in the circumferential direction of the spindle 40, so that air is supplied in a well-balanced manner between the spindle 40 and the bearing bush 2. be able to. As a result, the rotation of the spindle 40 can be made more stable.

Further, in the first embodiment, as described above, the first air passages (20, 21) and the second air passages 22, 23 are alternately arranged one by one in the circumferential direction of the main shaft 40. As a result, the axial diaphragm holes 20a, 21a, 22a, 23a and the radial diaphragm holes 20b, 21b can be arranged in a more balanced manner in the circumferential direction of the spindle 40, so that the rotation of the spindle 40 can be further stabilized.

Further, in the first embodiment, as described above, the first air passages (20, 21) and the second air passages 22, 23 adjacent to each other are arranged at equal intervals as a whole. As a result, the air flow in the circumferential direction of the spindle 40 can be made rotationally symmetric with respect to the central axis α of the spindle 40, so that the rotation of the spindle 40 can be further stabilized.

Further, in the first embodiment, as described above, the first air passages (20, 21) have an axial narrowing hole 20a and a radial narrowing hole 20b for supplying air to one side in the axial direction of the main shaft 40. A first air passage 20 on one side and a first air passage 21 on the other side having an axial throttle hole 21a and a radial throttle hole 21b for supplying air to the other side in the axial direction of the main shaft 40 are provided. Air supply units 3a and 3b capable of separately supplying air are provided in the air passage 20 and the first air passage 21 on the other side. As a result, the first air passage 20 on one side and the first air passage 21 on the other side can supply air to both sides in the axial direction in a well-balanced manner. As a result, the rotation of the spindle 40 can be made more stable.

Further, in the first embodiment, as described above, the rotating body 4 is provided at one end in the axial direction of the main shaft 40, and air is supplied from the first air passage 20 on one side to the bearing bush 2. The air-supplied surface 41a to be supplied and the air-supplied surface 42a provided at the other end in the axial direction of the main shaft 40 and to which air is supplied from the first air passage 21 on the other side to the bearing bush 2. By providing the air supply unit 3a, the supply of air to the first air passage 20 on one side is stopped, and the air supply unit 3b continues to supply air to the first air passage 21 on the other side. The supplied surface 41a is configured to be in close contact with the bearing bush 2 and clamped. As a result, the air supply unit 3a stops supplying air to the first air passage 20 on one side, and the air supply surface 41a is clamped to the bearing bush 2 while the air supply unit 3b is on the other side. Air can be supplied to the first air passage 21. As a result, even in the clamped state, air can be continuously supplied between the bearing bush 2 and the spindle 40 to the other side in the radial direction and the axial direction. As a result, galling (friction) between the bearing bush 2 and the spindle 40 can be suppressed while strongly clamping the air-supplied surface 41a.

Further, in the first embodiment, as described above, the rotating body 4 has a flat plate-shaped first rotary table 41 having an air-supplied surface 41a and a flat-plate-shaped second rotating table 42 having an air-supplied surface 42a. And are provided. As a result, the rotating body 4 can effectively receive the axial air and the radial air from the bearing bush 2 by the first rotary table 41, the second rotary table 42, and the spindle 40.

(Second Embodiment)
Next, the aerostatic bearing device 200 of the second embodiment will be described with reference to FIGS. 5 to 7. In this second embodiment, in addition to the configuration of the first embodiment, the rotating body 4 is provided with a first ventilation space (bearing space) 43a and a second ventilation space (bearing space) 43b, and an exhaust hole is provided in the housing portion 1. An example in which 10a is provided will be described.

As shown in FIG. 5, in the pneumatic bearing device 200 according to the second embodiment, the rotating body 4 includes a first ventilation space 43a and a second ventilation space 43b. Further, the installation housing portion 10 of the housing portion 1 includes an exhaust hole 10a.

The first ventilation space 43a is formed near one (A1 direction) side end of the main shaft 40. The first ventilation space 43a penetrates the radial outer side (B1 direction side) and the radial inner side (B2 direction side) of the rotating body 4 in the vicinity of the end portion of the main shaft 40 in the A1 direction. The first ventilation space 43a has a function of passing air from the bearing surface side (the surface on the A1 direction side) of the bearing bush 2 to the cylindrical inner surface 40a side of the spindle 40 on the air supply surface 41a side. The first ventilation space 43a extends along the air supply surface 41a.

The second ventilation space 43b is formed near the end of the main shaft 40 on the opposite side (A2 direction) from the first ventilation space 43a. The second ventilation space 43b penetrates the radial outer side (B1 direction side) and the radial inner side (B2 direction side) of the rotating body 4 in the vicinity of the end portion of the main shaft 40 in the A2 direction. The second ventilation space 43b allows air to pass from the bearing surface side (A2 direction side surface) of the bearing bush 2 to the cylindrical inner surface 40a side of the spindle 40 on the air supply surface 42a side opposite to the air supply surface 41a. It has a function. The second ventilation space 43ba extends along the air supply surface 42a.

As shown in FIG. 6, between the inner surface 40a of the cylinder of the main shaft 40 and the housing portion 1 located inside the inner surface 40a of the cylinder, the main shaft 40 and the housing portion 1 do not come into contact with each other in the B direction. , A gap T1 is provided. Further, a gap T2 is provided between the surface of the second rotary table 42 on the A2 direction side and the housing portion 1 so that the second rotary table 42 and the housing portion 1 do not come into contact with each other in the A direction. Has been done. The end of the gap T1 on the A2 direction side and the end of the gap T2 on the B2 direction side are connected so that air can pass through.

One end of the exhaust hole 10a is connected to the gap T2 so that air can be received from the gap T2. The exhaust hole 10a is provided at a position on the other side (A2 direction side) of the air supply surface 42a in the axial direction (A direction). Specifically, the exhaust hole 10a is connected so that the second rotary table 42 can be exhausted from the A2 direction side to the outer peripheral surface side of the housing portion 1 (installation housing portion 10).

(Air discharge in the clamped state)
Next, with reference to FIG. 7, the discharge of air in the clamped state will be described. The clamped state means a state in which the air supply from the air supply unit 3a is stopped and the air is supplied only from the air supply unit 3b, and the first rotary table 41 is in close contact with and fixed to the bearing bush 2. .. In this state, air hardly passes between the first rotary table 41 and the bearing bush 2.

The air emitted from the radial throttle hole 21b mainly passes through the first ventilation space 43a, the gaps T1 and T2, and is discharged from the exhaust hole 10a.

A gap T3 is provided between the surface of the second rotary table 42 on the B1 direction side and the housing portion 1 so that the second rotary table 42 and the housing portion 1 do not come into contact with each other in the B direction. There is. The end of the gap T2 on the B1 direction side and the end of the gap T3 on the A2 direction side are connected so that air can pass through. The air emitted from the axial throttle hole 21a mainly passes through the second ventilation space 43b, the gaps T3 and T2, and is discharged from the exhaust hole 10a.

Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of the second embodiment)
In the second embodiment, the following effects can be obtained.

In the second embodiment, as described above, the spindle 40 is formed in a cylindrical shape, and air is supplied to the rotating body 4 from the bearing surface side of the bearing bush 2 to the cylindrical inner surface side of the spindle 40 on the air supply surface 41a side. A first ventilation space 43a for passing is provided. As a result, the first ventilation space 43a makes it easier for air to flow from the other side first air passage 21 side to the air supply surface 41a side (one side first air passage 20 side in a state where air is not supplied). Therefore, galling (friction) between the bearing bush 2 and the spindle 40 can be further suppressed.

Further, in the second embodiment, as described above, the bearing bush 2 is fixedly attached, and the housing portion 1 to which the rotating body 4 is rotatably attached is provided, and the housing portion 1 is provided with the air supply surface 42a rather than the air supply surface 42a. An exhaust hole 10a for exhausting air from the first ventilation space 43a is provided at a position on the other side in the axial direction. Here, for example, when an exhaust hole is provided between the first air passage 20 on one side and the first air passage 21 on the other side to stop (clamp) the air supply to the first air passage 20 on one side. The air from the first air passage 21 on the other side is discharged to the outside through the exhaust hole with almost no passage through the first ventilation space 43a. Therefore, the air from the first air passage 21 on the other side is not supplied to a wide range between the spindle 40 and the bearing bush 2, and galling is likely to occur. Therefore, by configuring as described above, the air from the first air passage 21 on the other side can be effectively guided to the first ventilation space 43a, and the air from the first ventilation space 43a can be effectively guided through the exhaust hole 10a. Since the air can be exhausted, the air from the other side first air passage 21 side is sent to the clamped air supply surface 41a side (one side first air passage 20 side in the state where air is not supplied). It can be made easier to flow. As a result, galling (friction) between the bearing bush 2 and the spindle 40 can be further suppressed.

Further, in the second embodiment, as described above, the first ventilation space 43a is formed in the vicinity of one end of the main shaft 40 on the air supply surface 41a side. As a result, the air that generates the pressure in the radial direction from the first air passage 21 side on the other side can be guided to the vicinity of one end on the air supply surface 41a side of the spindle 40, so that the air in the radial direction at the time of clamping can be guided. It is possible to suppress the occurrence of misalignment and further suppress galling (friction) between the bearing bush 2 and the spindle 40.

Further, in the second embodiment, as described above, the rotating body 4 is provided with a second ventilation space 43b for passing air from the air-supplied surface 42a side of the bearing bush 2 to the inner surface side of the cylinder of the spindle 40. The two ventilation spaces 43b are formed near the other end of the main shaft 40 on the opposite side (A2 direction side) from the first ventilation space 43a. As a result, air can be ventilated to the inside of the spindle 40 from the vicinity of both ends in the axial direction (A direction) of the spindle 40 by the first ventilation space 43a and the second ventilation space 43b, respectively. Air can be effectively spread over the entire outer surface of the 40 cylinders. As a result, it is possible to further suppress the occurrence of positional deviation in the radial direction during clamping, and further suppress galling (friction) between the bearing bush 2 and the spindle 40.

(Modification example)
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

For example, in the first and second embodiments, the aerial hydrostatic bearing device is arranged so that the spindle extends in the vertical direction, but the present invention is not limited to this. In the present invention, the pneumatic bearing device may be arranged so that the spindle extends in the horizontal direction or the oblique direction.

Further, in the first and second embodiments, an example is shown in which the first air passage on one side (first air passage on the other side) and the second air passage may be alternately arranged one by one in the radial direction. However, the present invention is not limited to this. In the present invention, for example, the first air passage on one side, the first air passage on one side, and the second air passage may be alternately arranged in the radial direction (by repetition).

Further, in the first and second embodiments, examples in which radial diaphragm holes are arranged at intervals of 30 degrees pitch are shown, but the present invention is not limited to this. In the present invention, for example, radial diaphragm holes may be arranged at 45 degree pitch intervals.

Further, in the first and second embodiments, examples in which axial diaphragm holes are arranged at intervals of 15 degrees pitch are shown, but the present invention is not limited to this. In the present invention, for example, radial diaphragm holes may be arranged at 10-degree pitch intervals.

1 Housing 2 Bearing bush (Bearing body)
3a, 3b Air supply part 4 Rotating body 10a Exhaust holes 20a, 21a, 22a, 23a Axial throttle holes 20b, 21b Radial throttle holes 20 One side first air passage 21 The other side first air passage 22, 23 Second air passage 40 Main shaft 40a Cylindrical inner surface 41 First rotation table 41a Air supply surface (first rotation surface)
42 Second rotary table 42a Air supply surface (second rotary surface)
43a 1st ventilation space 43b 2nd ventilation space 100, 200 Aerostatic bearing device

Claims (11)

A rotating body including the spindle and
A bearing body portion arranged on the radial side of the spindle so as to surround the spindle is provided.
The bearing main body includes an axial throttle hole for supplying air between the bearing main body and the rotating body from the axial direction of the spindle, and the bearing main body and the rotating body from the radial direction of the main shaft. a plurality of first air passage and a radial throttle bore for supplying air between, without a said radial throttle bore, viewed contains a plurality of second air passage having said axial aperture hole,
The axial diaphragm holes are provided at first intervals in the circumferential direction of the spindle.
An aerostatic bearing device in which the radial throttle holes are provided at a second interval different from the first interval in the circumferential direction of the spindle . The axial aperture hole is provided evenly in the first gap the entire circumference of the main shaft,
The radial throttle holes, all in the larger second interval than the first intervals in the circumferential provided evenly, aerostatic bearing device according to claim 1 of the main spindle. The pneumatic bearing device according to claim 1 or 2, wherein the first air passage and the second air passage are alternately arranged one by one in the circumferential direction of the main shaft. The aerostatic bearing device according to claim 3, wherein the first air passage and the second air passage adjacent to each other are arranged at equal intervals as a whole. The first air passage has the axial throttle hole for supplying air to one side of the spindle in the axial direction, the first air passage on one side having the radial throttle hole, and the other side in the axial direction of the spindle. It has the axial throttle hole for supplying air and the first air passage on the other side having the radial throttle hole.
The pneumatic static bearing device according to any one of claims 1 to 4, further comprising an air supply unit capable of separately supplying air to the one-sided first air passage and the other-side first air passage. The rotating body is provided at one end in the axial direction of the spindle, and has a first rotating surface to which air is supplied from the one-sided first air passage to the bearing body, and a shaft of the spindle. A second rotating surface provided at the other end in the direction and to which air is supplied from the first air passage on the other side to the bearing main body is included.
The supply of air to the first air passage on one side by the air supply unit is stopped, and the supply of air to the first air passage on the other side by the air supply unit is continued. The pneumatic bearing device according to claim 5, wherein the rotating surface is configured to be in close contact with the bearing body and clamped. The spindle has a cylindrical shape and has a cylindrical shape.
The pneumatic static bearing according to claim 6, wherein the rotating body includes a first ventilation space for passing air from the bearing surface side of the bearing body portion to the cylindrical inner surface side of the spindle on the first rotating surface side. apparatus. The bearing body portion is fixedly attached, and the housing portion to which the rotating body is rotatably attached is further provided.
The pneumatic bearing device according to claim 7, wherein the housing portion includes an exhaust hole for exhausting air from the first ventilation space at a position on the other side of the second rotating surface in the axial direction. The pneumatic bearing device according to claim 7 or 8, wherein the first ventilation space is formed in the vicinity of one end of the main shaft on the first rotating surface side. The rotating body includes a second ventilation space for passing air from the second rotating surface side of the bearing body portion to the cylindrical inner surface side of the spindle.
The pneumatic bearing device according to any one of claims 7 to 9, wherein the second ventilation space is formed in the vicinity of the other end of the spindle opposite to the first ventilation space. The rotary body includes any one of claims 6 to 10 including a flat plate-shaped first rotary table having the first rotating surface and a flat plate-shaped second rotating table having the second rotating surface. The pneumatic bearing device described.

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