JP2018109429A - Air hydrostatic bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air hydrostatic bearing device which can acquire large bearing rigidity easily, and which can simplify a device structure (passage structure).SOLUTION: An air hydrostatic bearing device 100 includes: a rotary body 4 including a main shaft 40; and a bearing bush 2 arranged radially outside of the main shaft 40 so as to surround the main shaft 40. The bearing bush 2 includes: a plurality of first air passages 20(21) having an axial throttle hole 20a(21a) for supplying air between the bearing bush 2 and the rotary body 4 from an axial direction of the main bearing 40, and a radial throttle hole 20b(21b) for supplying air between the bearing bush 2 and the rotary body 4 from a radial direction of the main shaft 40; and a plurality of second air passages 22(23) having no radial throttle hole but having an axial throttle hole 22a(23a).SELECTED DRAWING: Figure 1

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.

  2. Description of the Related Art Conventionally, an aerostatic bearing device including a bearing main body portion having an axial throttle hole and a radial throttle hole is known (see, for example, Patent Document 1).

  Patent Document 1 discloses an apparatus including a rotor (rotary body) including a shaft (main shaft) and an air bearing (bearing body portion). The air bearing is disposed radially outside the shaft so as to surround the shaft. 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 an air bearing and the rotating body from the radial direction (radial direction) of the shaft. The same number of passages for supplying air are provided separately.

  Here, in the air bearing, the bearing rigidity greatly affects the mechanical performance. The bearing stiffness is affected at least by the air pressure in the axial direction of the shaft (main shaft), the magnitude of air pressure in the radial direction of the shaft, the diameter of the throttle, and the bearing clearance.

Japanese Utility Model Publication No. 5-10824

  However, in Patent Document 1, the number of passages for supplying air from the axial direction (axial direction) of the shaft and the number of passages for supplying air from the radial direction (radial direction) of the shaft are the same. There is a problem that it is difficult to make the air pressure in the direction larger than the air pressure in the radial direction so as to obtain a large bearing rigidity. In addition, 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-described problems, and one object of the present invention is to easily obtain a large bearing rigidity and to simplify the device configuration (passage structure). It is to provide a simple hydrostatic bearing device.

  An aerostatic bearing device according to one aspect of the present invention includes a rotating body including a main shaft, and a bearing main body portion disposed radially outside the main shaft so as to surround the main shaft. An axial throttle hole for supplying air between the bearing main body and the rotary body from the axial direction, and a radial throttle hole for supplying air between the bearing main body and the rotary body from the radial direction of the main shaft A plurality of first air passages, and a plurality of second air passages having an axial throttle hole without having a radial throttle hole.

  In the aerostatic bearing device according to one aspect of the present invention, as described above, the axial throttle hole for supplying air between the bearing body portion and the rotating body from the axial direction of the main shaft to the bearing body portion, A plurality of first air passages having a radial throttle hole for supplying air between the bearing body portion and the rotating body from the radial direction of the main shaft, and the axial throttle hole without the radial throttle hole. And a plurality of second air passages. Thereby, since the axial throttle hole and the radial throttle hole can be integrally provided in the first air passage, at least a part of the air passage can be shared. For this reason, the apparatus configuration (passage structure) can be simplified. Further, since the bearing body is provided with more axial restrictive holes than radial restrictive holes, large bearing rigidity can be easily obtained. Therefore, the hydrostatic bearing device can easily obtain a large bearing rigidity and can simplify the device configuration (passage structure).

  In the display device according to the one aspect described above, preferably, the axial throttle holes are provided uniformly at the first interval around the main shaft, and the radial throttle holes are larger than the first interval around the main shaft. Evenly spaced at two intervals. If comprised in this way, since an axial restricting hole and a radial restricting hole are arrange | positioned with sufficient balance in the circumferential direction of a main axis | shaft, air can be supplied with good balance between a main axis | shaft and a bearing main-body part. As a result, the rotation of the main shaft can be further stabilized.

  In the display device according to the above aspect, the first air passage and the second air passage are preferably alternately arranged one by one in the circumferential direction of the main shaft. If comprised in this way, since an axial aperture hole and a radial aperture hole can be arrange | positioned with sufficient balance in the circumferential direction of a main axis | shaft, rotation of a main axis | shaft can be stabilized further.

  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. If comprised in this way, since the flow of the air in the circumferential direction of a main axis | shaft can be made rotationally symmetrical with respect to the center axis line of a main axis | shaft, rotation of a main axis | shaft can be stabilized further.

  In the display device according to the above aspect, the first air passage is preferably configured such that the first air passage includes an axial restricting hole and a radial restricting hole for supplying air to one side in the axial direction of the main shaft, and the main shaft. An axial throttle hole for supplying air to the other side in the axial direction and a first air passage on the other side having a radial throttle hole, and separately supplying air to the first air passage on the one side and the first air passage on the other side. The air supply part which can supply is further provided. If comprised in this way, air can be supplied with sufficient balance to the both sides of an axial direction by the one side 1st air path and the other side 1st air path. As a result, the rotation of the main shaft can be further stabilized.

  In this case, preferably, the rotating body is provided at one end portion in the axial direction of the main shaft, and the first rotating surface to which air is supplied from the one side first air passage to the bearing body portion, and the main shaft. A second rotation surface that is provided at the other end in the axial direction and is supplied with air from the other side first air passage to the bearing main body, and is provided to the first side first air passage by the air supply unit. The supply of air is stopped, and the supply of air to the other first air passage by the air supply unit is continued, so that the first rotating surface comes into close contact with the bearing body and is clamped. It is configured. If comprised in this way, an air supply part will stop supply of the air to one side 1st air path, and it will be in the state which clamped the 1st rotating surface to the bearing main-body part, and will be to the other side 1st air path. The air can be supplied. Thereby, even in the clamped state, it is possible to continue supplying air to the other side in the radial direction and the axial direction between the bearing main body portion and the main shaft. As a result, galling (friction) between the bearing body and the main shaft 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 main body portion, preferably, the main shaft has a cylindrical shape, and the rotating body is the main shaft from the bearing surface side of the bearing main body portion on the first rotating surface side. Includes a first ventilation space (bearing space, that is, a space that allows air to pass between the inside and the outside of the main shaft). If comprised in this way, it will be easy to flow air to the 1st rotation surface side (one side 1st air passage side in the state where air is not supplied) clamped from the other side 1st air passage side by the 1st ventilation space. Therefore, it is possible to further suppress galling (friction) between the bearing main body portion and the main shaft.

  In the configuration in which the main shaft includes the first ventilation space, preferably, the bearing main body portion is fixedly attached, and the main body further includes a housing portion to which the rotating body is rotatably attached, and the housing portion has a shaft more than the second rotating surface. An exhaust hole for exhausting air from the first ventilation space is included at a position on the other side in the direction. 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, and the air supply to the first air passage on the one side is stopped (clamped), the other The air from the side first air passage is discharged outside without passing through the first ventilation space. For this reason, air from the first air passage on the other side is not supplied to a wide range between the main shaft and the bearing main body, and galling is likely to occur. Therefore, by configuring as described above, air from the other first air passage can be guided to the first ventilation space, and 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 more easily flown to the clamped first rotation surface side (one side first air passage side in a state where no air is supplied). As a result, it is possible to further suppress galling (friction) between the bearing main body and the main shaft.

  In the configuration in which the main shaft includes the first ventilation space, the first ventilation space is preferably formed in the vicinity of one end of the main shaft on the first rotation surface side. If comprised in this way, since the air which produces the pressure of the radial direction from the other side 1st air passage side can be guide | induced to the one end part vicinity of the 1st rotation surface side of a main axis | shaft, it will be radial direction in the case of clamping Can be prevented, and the galling (friction) between the bearing main body and the main shaft can be further suppressed.

  In the configuration in which the rotating body includes the first ventilation space, the rotating body preferably includes a second ventilation space for allowing air to pass from the second rotation surface side of the bearing main body portion to the cylindrical inner surface side of the main shaft, and the second ventilation space. The ventilation space is formed in the vicinity of the other end on the opposite side of the main shaft from the first ventilation space. If comprised in this way, since air can be ventilated to the inner side of the main shaft from the vicinity of both ends in the axial direction of the main shaft by two of the first ventilation space and the second ventilation space, the cylindrical outer surface of the main shaft Can effectively spread the air throughout. As a result, it is possible to further suppress the occurrence of radial displacement during clamping, and to further suppress galling (friction) between the bearing main body and the main shaft.

  In the configuration in which the first rotating surface is clamped in close contact with the bearing main body, preferably, the rotating body is a flat plate-shaped first rotating table having the first rotating surface and a flat plate-shaped having the second rotating surface. A second rotary table. If comprised in this way, a rotary body can receive axial direction air and radial direction air from a bearing main-body part effectively by a 1st turntable, a 2nd turntable, and a main axis | shaft.

  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 the 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 the 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 flow of the air of the aerostatic bearing apparatus by 2nd Embodiment of this invention. It is a figure for demonstrating the flow of the air of the clamped 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)
With reference to FIGS. 1-4, the structure of the aerostatic bearing apparatus 100 by 1st Embodiment of this invention is demonstrated.

(Configuration of aerostatic bearing device)
As shown in FIG. 1, an aerostatic bearing device 100 according to the first embodiment of the present invention includes a housing part 1, a bearing bush 2, air supply parts 3a and 3b, a rotating body 4, a motor 5, and an encoder. 6 is provided. The rotating body 4 includes a main shaft 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, the A2 direction is the downward direction), and the radial direction (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 the “bearing body” in the claims.

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

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

  The installation housing part 10 is a part that supports each component of the aerostatic bearing device 100, and is a part (member) that is installed on the installation surface by a bolt or the like. In addition, the installation housing 10 includes a cylindrical portion 110 on the inner side (B2 direction side) and a flat portion extending from one end (A2 direction side end portion) to the outer side (B1 direction side) of the cylindrical portion 110 (B1 direction side). (Installed portion) 111. In addition, an air supply housing 11, a motor 5, and an encoder 6 are attached to the installation housing 10.

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

  The air supply housing portion 11 has air passages 11 a and 11 b that are passages from the outer surface to the inner surface and for supplying air to the bearing bush 2. Both air passages 11a and 11b extend in the B direction. The air passages 11a and 11b are provided in two rows at a predetermined interval in the A direction. The air passage 11a is disposed 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 (each at a 15 ° pitch on the entire circumference).

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

  The bearing bush 2 includes a plurality of first air passages having an axial throttle hole and a radial throttle hole, and a plurality of second air passages 23 having no axial throttle hole and having an axial throttle hole. . The first air passage includes one side first air passage 20 and the other side first air passage 21. 2, the bearing bush 2 includes 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. The air supply surface 120 is connected to end portions on the A1 direction side of axial throttle holes 20a and 22a described later. The air supply surface 121 is connected to the A2 direction end of axial throttle holes 21a and 23a described later. The air supply surface 122 is connected to inner ends (B2 direction side) ends of radial throttle holes 20b and 21b described later.

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

  As shown in FIG. 3, the first air passage 20 on the one side and the first air passage 21 on the other side are arranged at positions overlapping each other when viewed from the A direction. That is, the position of the one side 1st air path 20 and the other side 1st air path 21 is 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 are the same in the circumferential direction (C direction).

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

  As shown in FIG. 4, the other first air passage 21 and the second air passage 23 are alternately arranged one by one in the circumferential direction (C direction) of the main shaft 40. 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 one-side first air passage 20 extends from the axial direction of the main shaft 40 between the bearing bush 2 and the rotating body 4 (first rotary table 41) and in the axial direction of the main shaft 40. On one side (A1 direction side), there are an axial throttle hole 20a and a radial throttle hole 20b for supplying air. 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. The axial throttle hole 20a is configured to supply (discharge) air from the air supply surface 120, as shown in FIG. The radial throttle hole 20b is configured to supply (discharge) air from the air supply surface 122.

  Both the axial throttle hole 20a and the radial throttle hole 20b are self-throttling holes. The self-made throttle hole means a small-diameter throttle hole directly formed 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-formed throttle hole. The orifice throttle hole means a small-diameter throttle hole formed by mounting an orifice in a 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 20 b is a hole for supplying air between the inner surface (surface on the B2 direction side) of the bearing bush 2 and the main shaft 40. The air supplied surface 41a is an example of the “first rotating surface” in the claims.

  The other first air passage 21 is between the bearing bush 2 and the rotating body 4 (second rotary table 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. In addition, an axial throttle hole 21a and a radial throttle hole 21b for supplying air are provided. 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 21 a is configured to supply (discharge) air from the air supply surface 121. The radial throttle hole 21 b is configured to supply (discharge) air from the air supply surface 122. Both the axial throttle hole 21a and the radial throttle hole 21b are self-made throttle holes.

  As shown in FIG. 1, the axial throttle hole 21 a is a hole for supplying air between the surface on the A2 direction side of the bearing bush 2 and the second rotary table 42 (an air supply surface 42 a described later). is there. Further, the radial throttle hole 20 b is a hole for supplying air between the inner surface (surface on the B2 direction side) of the bearing bush 2 and the main shaft 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 22 a that supplies air between the bearing bush 2 and the first rotary table 41. The axial throttle hole 22 a 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 throttle hole 22a is a self-made throttle hole.

  Further, the second air passage 23 has an axial throttle hole 23 a for supplying air between the bearing bush 2 and the second rotary table 42 without having a radial throttle hole. 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 23 a is configured to supply (discharge) air from the air supply surface 121. The axial throttle hole 23a is a self-made throttle hole.

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

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

  As shown in FIG. 3, the radial throttle holes 20b on the A1 direction side are 30 ° pitch intervals larger than the intervals (15 ° pitch intervals) where the axial throttle holes 20a and 22a on the A1 direction side are provided. It is evenly provided around the circumference.

  As shown in FIG. 4, the radial throttle holes 21b on the A2 direction side are 30 ° pitch intervals larger than the intervals (15 ° pitch intervals) where the axial throttle holes 21a and 23a on the A2 direction side are provided. It is evenly provided around the circumference.

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

  The air supply part 3b is arrange | positioned at the A2 direction side of the air supply part 3a. In addition, the air supply part 3b is supplied from the outside in the B direction of the bearing bush 2 to the other side first air passage 21 and second air passage 23 via the air passage 11b on the A2 direction side of the air supply housing part 11. It is configured to be able to supply.

  Moreover, the air supply part 3a and the air supply part 3b are comprised so that supply of air to the bearing bush 2 can be carried out separately, and supply of air can be stopped.

  The surface of the bearing bush 2 on the first rotary table 41 side (A1 direction side) is lapped.

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

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

  The first rotary table 41 is provided on the A1 direction side of the main shaft 40. The first turntable 41 has a circular flat plate shape. The first turntable 41 has an air supply surface 41a on the main shaft side (A2 direction side) and an installation surface 41b on the opposite side (A1 direction side) to the main shaft side. The air supplied surface 41 a is a surface through which air is supplied from the first air passage 20 and the second air passage 22 to the bearing bush 2. The air supply surface 41 a is disposed so as to face the air supply surface 120 of the bearing bush 2 that is lapped. The installation surface 41b is a surface on which, for example, a workpiece is installed.

  The second rotary table 42 is provided at the other end portion (end portion on the A2 direction side) of the main shaft 40. The second turntable 42 has an annular shape with an outer diameter smaller than that of the first turntable 41. The second turntable 42 has an air supply surface 42a. The air supply surface 42a is provided at the other end portion (end portion on the A2 direction side) of the main shaft 40, 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. The air supply surface 42 a is disposed so as to face the air supply surface 121 of the bearing bush 2.

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

(Motor and encoder)
As shown in FIG. 1, the motor 5 is disposed inside the installation housing unit 10 and the main shaft 40 of the housing unit 1. That is, the motor 5 is a so-called built-in motor incorporated inside the main spindle system. The motor 5 includes a stator 50 and a rotor 51. The stator 50 is attached to the inner surface of the installation housing part 10 of the housing part 1. Further, the rotor 51 is connected to the first rotary table 41 and is configured to apply a 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 the motor 5 (rotates) based on the acquired value of the encoder 6. The rotation of the body 4 is controlled.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the axial throttle holes 20 a and 21 a for supplying air between the bearing bush 2 and the rotating body 4 from the axial direction of the main shaft 40 to the bearing bush 2, and the main shaft 40. 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 bearing bush 2 and the 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, 21a and the radial throttle holes 20b, 21b can be integrally provided in the first air passage (20, 21), so that at least a part of the air passages can be shared. it can. For this reason, the apparatus configuration (passage structure) can be simplified. Further, since the bearing bush 2 is provided with more axial throttle holes 20a, 21a, 22a, and 23a than the radial throttle holes 20b and 21b, large bearing rigidity can be easily obtained. Therefore, the aerostatic bearing device 100 can easily obtain a large bearing rigidity and can simplify the device configuration (passage structure).

  In the first embodiment, as described above, the axial throttle holes 20 a, 21 a, 22 a, 23 a are provided uniformly at the first interval around the main shaft 40, and the radial throttle holes 20 b, 21 b are provided on the main shaft 40. It is evenly provided on the entire circumference at a second interval (30 ° pitch interval) larger than the first interval (15 ° pitch interval). Thus, the axial throttle holes 20a, 21a, 22a, 23a and the radial throttle holes 20b, 21b are arranged in a balanced manner in the circumferential direction of the main shaft 40, so that air is supplied between the main shaft 40 and the bearing bush 2 in a balanced manner. be able to. As a result, the rotation of the main shaft 40 can be further stabilized.

  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 throttle holes 20a, 21a, 22a, 23a and the radial throttle holes 20b, 21b can be arranged in a more balanced manner in the circumferential direction of the main shaft 40, so that the rotation of the main shaft 40 can be further stabilized.

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

  In the first embodiment, as described above, the first air passage (20, 21) has the axial throttle hole 20a and the radial throttle hole 20b for supplying air to one side in the axial direction of the main shaft 40. One side first air passage 20 and the other side first air passage 21 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 portions 3a and 3b capable of supplying air separately to the air passage 20 and the other first air passage 21 are provided. Thereby, air can be supplied with good balance to both sides in the axial direction by the first air passage 20 on the one side and the first air passage 21 on the other side. As a result, the rotation of the main shaft 40 can be further stabilized.

  In the first embodiment, as described above, the rotating body 4 is provided at one end portion in the axial direction of the main shaft 40, and air is supplied from the one side first air passage 20 to the bearing bush 2. An air supplied surface 41a, and an air supplied surface 42a provided at the other end in the axial direction of the main shaft 40 and supplied with air from the other side first air passage 21 to the bearing bush 2. The supply of air to the one side first air passage 20 by the air supply unit 3a is stopped and the supply of air to the other side first air passage 21 by the air supply unit 3b is continued. The supplied surface 41a is configured to be in close contact with the bearing bush 2 and clamped. As a result, the air supply part 3a stops supplying air to the first air passage 20 on one side and the air supply surface 41a is clamped on the bearing bush 2 while the air supply part 3b is on the other side. Air can be supplied to the first air passage 21. Thereby, even in the clamped state, it is possible to continue supplying air to the other side in the radial direction and the axial direction between the bearing bush 2 and the main shaft 40. As a result, galling (friction) between the bearing bush 2 and the main shaft 40 can be suppressed while strongly clamping the air supplied surface 41a.

  In the first embodiment, as described above, the rotating body 4 includes the flat plate-shaped first rotary table 41 having the air supplied surface 41a and the flat plate-shaped second rotary table 42 having the air supplied surface 42a. And provide. Thereby, the rotary body 4 can effectively receive axial air and radial air from the bearing bush 2 by the first rotary table 41, the second rotary table 42 and the main shaft 40.

(Second Embodiment)
Next, an aerostatic bearing device 200 according to the second embodiment will be described with reference to FIGS. In the 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 the housing portion 1 has an exhaust hole. An example in which 10a is provided will be described.

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

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

  The 2nd ventilation space 43b is formed in the edge part vicinity of the opposite side (A2 direction) of the main axis | shaft 40 with respect to the 1st ventilation space 43a. The second ventilation space 43b passes through the radially outer side (B1 direction side) and the radially inner side (B2 direction side) of the rotating body 4 in the vicinity of the end portion on the A2 direction side of the main shaft 40. The second ventilation space 43b allows air to pass from the bearing surface side (surface in the A2 direction) of the bearing bush 2 to the cylindrical inner surface 40a side of the main shaft 40 on the air supplied surface 42a side opposite to the air supplied surface 41a. It has a function. The second ventilation space 43ba extends along the air supply surface 42a.

  As shown in FIG. 6, the main shaft 40 and the housing portion 1 are not in contact with each other in the B direction between the cylindrical inner surface 40a of the main shaft 40 and the housing portion 1 located inside the cylindrical inner surface 40a. A gap T1 is provided. Further, a gap T2 is provided between the surface on the A2 direction side of the second turntable 42 and the housing portion 1 so that the second turntable 42 and the housing portion 1 do not contact in the A direction. It has been. The end portion on the A2 direction side of the gap T1 and the end portion on the B2 direction side of the gap T2 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) in the axial direction (A direction) from the air supply surface 42a. Specifically, the exhaust hole 10a is connected to the outer peripheral surface side of the housing part 1 (installation housing part 10) from the A2 direction side of the second turntable 42 so as to be able to exhaust air.

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

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

  A gap T3 is provided between the surface of the second turntable 42 on the B1 direction side and the housing portion 1 so that the second turntable 42 and the housing portion 1 do not contact in the B direction. Yes. The end portion on the B1 direction side of the gap T2 and the end portion on the A2 direction side of the gap T3 are connected so that air can pass through. The air exiting from the axial throttle hole 21a mainly passes through the second ventilation space 43b and 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 2nd Embodiment)
In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the main shaft 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 main shaft 40 on the air supply surface 41a side. A first ventilation space 43a is provided for passage. As a result, the first ventilation space 43a allows air to easily flow to the air supply surface 41a side (one side first air passage 20 side in a state where no air is supplied) clamped from the other side first air passage 21 side. Therefore, the galling (friction) between the bearing bush 2 and the main shaft 40 can be further suppressed.

  Moreover, in 2nd Embodiment, the bearing bush 2 is fixedly attached as mentioned above, and the housing | casing part 1 to which the rotary body 4 is rotatably attached is provided, and the housing | casing part 1 is provided 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 one-side first air passage 20 and the other-side first air passage 21 to stop (clamp) the air supply to the one-side first air passage 20. The air from the other first air passage 21 is discharged outside through the exhaust hole without passing through the first ventilation space 43a. For this reason, air from the first air passage 21 on the other side is not supplied over a wide range between the main shaft 40 and the bearing bush 2, and galling is likely to occur. Therefore, by configuring as described above, the air from the other first air passage 21 can be effectively guided to the first ventilation space 43a, and from the first ventilation space 43a via the exhaust hole 10a. Since air can be exhausted, air from the other side first air passage 21 side is clamped to the clamped air supply surface 41a side (one side first air passage 20 side in a state where no air is supplied), It can be made easier to flow. As a result, galling (friction) between the bearing bush 2 and the main shaft 40 can be further suppressed.

  In the second embodiment, as described above, the first ventilation space 43a is formed in the vicinity of one end portion of the main shaft 40 on the air supplied surface 41a side. As a result, air that generates radial pressure from the first air passage 21 side on the other side can be guided to the vicinity of one end portion on the air supply surface 41a side of the main shaft 40. Generation | occurrence | production of position shift can be suppressed and the scuffing (friction) with the bearing bush 2 and the main axis | shaft 40 can be suppressed further.

  In the second embodiment, as described above, the rotating body 4 is provided with the second ventilation space 43b for allowing air to pass from the air supply surface 42a side of the bearing bush 2 to the cylindrical inner surface side of the main shaft 40. The two ventilation spaces 43b are formed in the vicinity of the other end of the main shaft 40 on the side opposite to the first ventilation space 43a (A2 direction side). Thereby, air can be ventilated inside the main shaft 40 from the vicinity of both end portions in the axial direction (direction A) of the main shaft 40 by the two of the first ventilation space 43a and the second ventilation space 43b. Air can be effectively spread over the entire 40 cylindrical outer surfaces. As a result, it is possible to further suppress the occurrence of radial displacement during clamping, and to further suppress galling (friction) between the bearing bush 2 and the main shaft 40.

(Modification)
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

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

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

  Moreover, in the said 1st and 2nd embodiment, although the example which arrange | positioned the radial aperture | diaphragm | restriction hole by 30 degree | times pitch spacing was shown, this invention is not limited to this. In the present invention, for example, the radial throttle holes may be arranged at a pitch interval of 45 degrees.

  In the first and second embodiments, the example in which the axial throttle holes are arranged at a pitch interval of 15 degrees is shown, but the present invention is not limited to this. In the present invention, for example, radial aperture holes may be arranged at a pitch interval of 10 degrees.

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

Claims (11)

A rotating body including a main shaft;
A bearing main body disposed on the outer side in the radial direction of the main shaft so as to surround the main shaft,
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 main shaft, and the bearing main body and the rotating body from the radial direction of the main shaft. Air including a plurality of first air passages having a radial throttle hole for supplying air between and a plurality of second air passages having the axial throttle hole without the radial throttle hole Hydrostatic bearing device. The axial throttle holes are evenly provided at a first interval on the entire circumference of the main shaft,
2. The hydrostatic bearing device according to claim 1, wherein the radial throttle holes are provided uniformly at a second interval larger than the first interval on the entire circumference of the main shaft.   The aerostatic 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 a 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 a first air passage having the axial throttle hole and the radial throttle hole for supplying air to one side of the main shaft in the axial direction, and the other side of the main shaft in the axial direction. The other side first air passage having the axial throttle hole for supplying air and the radial throttle hole,
The aerostatic bearing apparatus according to any one of claims 1 to 4, further comprising an air supply unit capable of separately supplying air to the one-side first air passage and the other-side first air passage. The rotating body is provided at one end in the axial direction of the main shaft, and a first rotating surface to which air is supplied from the one first air passage to the bearing main body, and the shaft of the main shaft A second rotating surface that is provided at the other end in the direction and is supplied with air from the other first air passage to the bearing main body,
The supply of air to the one side first air passage by the air supply unit is stopped, and the supply of air to the other side first air passage by the air supply unit is continued, whereby the first The aerostatic bearing apparatus according to claim 5, wherein the rotating surface is configured to be in close contact with the bearing main body portion and to be clamped. The main shaft has a cylindrical shape,
The aerostatic bearing according to claim 6, wherein the rotating body includes a first ventilation space for allowing air to pass from a bearing surface side of the bearing main body portion to a cylindrical inner surface side of the main shaft on the first rotating surface side. apparatus. The bearing main body is fixedly attached, and further includes a housing part to which the rotating body is rotatably attached,
The aerostatic bearing device according to claim 7, wherein the housing portion includes an exhaust hole that exhausts air from the first ventilation space at a position on the other side in the axial direction from the second rotation surface.   The aerostatic bearing device according to claim 7 or 8, wherein the first ventilation space is formed in the vicinity of one end portion of the main shaft on the first rotation surface side. The rotating body includes a second ventilation space for allowing air to pass from the second rotating surface side of the bearing body portion to the cylindrical inner surface side of the main shaft,
10. The aerostatic bearing device according to claim 7, wherein the second ventilation space is formed in the vicinity of the other end of the main shaft on the opposite side to the first ventilation space.   The rotating body includes a flat plate-shaped first rotating table having the first rotating surface and a flat plate-shaped second rotating table having the second rotating surface. The aerostatic bearing device described.

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