KR20150038502A - Gas-static bearing unit - Google Patents

Gas-static bearing unit Download PDF

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Publication number
KR20150038502A
KR20150038502A KR20157005284A KR20157005284A KR20150038502A KR 20150038502 A KR20150038502 A KR 20150038502A KR 20157005284 A KR20157005284 A KR 20157005284A KR 20157005284 A KR20157005284 A KR 20157005284A KR 20150038502 A KR20150038502 A KR 20150038502A
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South Korea
Prior art keywords
shaft
radial bearing
thrust
bearing
air
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KR20157005284A
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Korean (ko)
Inventor
사토시 우에다
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오일레스고교 가부시키가이샤
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Publication of KR20150038502A publication Critical patent/KR20150038502A/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0603—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion
    • F16C32/0614—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings
    • F16C32/0618—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings via porous material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0603—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion
    • F16C32/0614—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings
    • F16C32/0622—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings via nozzles, restrictors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0681—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load
    • F16C32/0685—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load for radial load only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0681—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load
    • F16C32/0696—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load for both radial and axial load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2300/00—Application independent of particular apparatuses
    • F16C2300/20—Application independent of particular apparatuses related to type of movement
    • F16C2300/22—High-speed rotation

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)

Abstract

A structure of a compact static pressure gas bearing unit that supports a rotating body rotating at a high speed in a simple structure and stably supports noncontact is provided. The two shaft holders 3A and 3B fix the air shaft unit 1 that supports the pulley 2 in a noncontact manner at both ends 113 and 12 thereof. The base body f is supplied from the radial bearing surface 1121 of the air shaft unit 1 to the radial bearing gap 60 between the radial bearing surface 1121 and the inner peripheral surface 221 of the pulley 2, The gas film f is formed in the bearing gap 60 and the thrust bearing surfaces 1132 and 121 of the air shaft unit 1 are connected to the radial bearing gap 60 from the radial bearing gap 60. [ And the thrust bearing clearances 61a and 61b between the boss end surfaces 241A and 241B of the pulley 2. A gas film is also formed in the thrust bearing gaps 61a and 61b by using the exhaust f1.

Figure P1020157005284

Description

Static gas bearing unit {GAS-STATIC BEARING UNIT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a both-ends-supported type static pressure gas bearing unit capable of supporting a component such as a pulley rotating at high speed in a simple structure and in a more non-contactable manner.

Patent Document 1 discloses an air bearing unit (static pressure air bearing device) for supporting a rotary shaft in a noncontact manner.

The air bearing unit is provided with a porous limiter for receiving a thrust load and a radial load of the shaft on respective bearing surfaces (thrust bearing surface and radial bearing surface), respectively, at both end sides of the inner periphery of a cylindrical housing into which a shaft Air bearing (static air bearing) of a restriction type (a porous body such as a porous graphite) are respectively provided. Here, the radial bearing surface is opposed to the outer peripheral surface of the shaft, and a radial bearing gap is formed between the radial bearing surface and the outer peripheral surface of the shaft. The thrust bearing surface is opposed to the flange formed on the outer periphery of the shaft, Thereby forming a gap.

Here, for each air bearing, an exhaust groove is formed in the circumferential direction on the inner circumferential surface of the housing on the side opposite to the thrust bearing surface (the center side of the inner circumferential surface of the housing) with the radial bearing surface of the air bearing therebetween, An exhaust hole penetrating through the outer peripheral surface of the housing is formed in the groove bottom. An exhaust hole is formed on the outer circumferential surface of the shaft at a position near the thrust bearing surface of the air bearing in the circumferential direction and an exhaust hole for connecting the exhaust groove to the exhaust groove on the inner circumferential surface of the housing Respectively.

In this configuration, the air supplied to the air bearing is ejected from the thrust bearing surface and the radial bearing surface of the air bearing, respectively. The air ejected from the thrust bearing surface flows inside the thrust bearing gap toward the outer periphery of the flange and is released to the outside from the thrust bearing gap. On the other hand, the air ejected from the radial bearing surface flows into the radial bearing clearance toward the exhaust grooves near the thrust bearing surface and the exhaust grooves on the opposite side of the thrust bearing surface, and flows into these exhaust grooves, And is exhausted to the outside of the housing.

Japanese Laid-Open Patent Publication No. 2008-57696

However, in the air bearing unit described in Patent Document 1, the air supplied to the gaps between the radial bearings is discharged to the positions on the opposite sides of the thrust bearing surface with the radial bearing surface between the positions near the thrust bearing surface, It is necessary to form an exhaust groove for the exhaust gas. In addition, it is necessary to form an exhaust hole in both the housing and the shaft for discharging the air introduced into these exhaust grooves to the outside of the housing. In addition, it is necessary to separately provide a thrust bearing surface and a radial bearing surface for ejecting compressed air on the inner circumference of the housing. Therefore, the structure becomes complicated.

Further, since the exhaust hole on the shaft side is formed along the axial direction of the shaft so as to connect the exhaust groove on the outer circumferential surface of the shaft and the exhaust groove on the inner circumferential surface of the housing, a somewhat large thickness is required for the shaft. For this reason, when the shaft becomes heavy, for example, the shaft may roll due to its own weight. Since the radial bearing gap formed between the radial bearing surface of the inner periphery of the housing (static pressure air bearing) and the outer peripheral surface of the shaft is very narrow, when the shaft is bent, the shaft and the air bearing come into contact with each other, There is a possibility that it can not be maintained.

However, if a rotating body such as a pulley rotating at a high speed is held by an air bearing, self-excited vibration may occur at the time of supply of air. As a result, resonance of the system results in, for example, obstruction of stable running of the transported object.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure of a both-end support type hydrostatic bearing unit in which a rotating body rotating at high speed is supported by a simple structure in a more non-

In order to solve the above problems, according to the present invention, a shaft unit inserted into a shaft insertion hole formed in an axial direction of the rotating body and supporting the rotating body in a noncontact manner is provided with a shaft- Fix at the inserted position from both sides. A radial bearing gap between the radial bearing surface and the inner circumferential surface of the shaft insertion hole of the rotating body is formed in the radial bearing gap between the radial bearing surface and the inner circumferential surface of the shaft insertion hole of the rotating body by the gas ejected from the radial bearing surface formed on the outer circumferential surface of the shaft unit, A gas film is formed and the gas is exhausted from the radial bearing gap into the thrust bearing gap between the thrust bearing surface of the shaft unit and each end surface of the rotating body. The exhausted gas is used to form a gas film in the gap of the thrust bearing.

For example, the present invention is a static pressure gas bearing unit for supporting a rotating body rotating in a direction about a shaft center in a noncontact manner by a gas film interposed between a radial bearing gap and a gap between the first and second thrust bearings,

A shaft unit inserted into a shaft insertion hole passing through both end faces of the rotating body,

And shaft holding means for holding the shaft unit at positions on both sides of the shaft insertion hole of the rotating body,

The shaft unit includes:

A radial bearing surface for forming the radial bearing gap between the inner peripheral surface of the shaft insertion hole and the inner peripheral surface and for ejecting a base for forming the gas film in the radial bearing gap,

And a radial bearing surface which is adjacent to the radial bearing surface and which is opposed to one end surface of the rotating body and which is connected to one end side of the radial bearing gap, A first thrust bearing surface forming a bearing gap,

And a second thrust bearing gap which is adjacent to the radial bearing surface and which is opposite to the other end surface of the rotating body and which is connected to the other end side of the radial bearing gap, Having a second thrust bearing surface,

The gas,

The radial bearing gap is discharged toward the first thrust bearing gap and the second thrust bearing gap to be exhausted from the radial bearing gap to the first thrust bearing gap and the second thrust bearing gap, The gas film is formed in the first thrust bearing gap and in the second thrust bearing gap, respectively.

According to the present invention, the compressed gas exhausted from the radial bearing gap formed between the inner circumferential surface of the shaft insertion hole of the rotating body and the radial bearing surface formed on the outer circumferential surface of the shaft unit, which faces the inner circumferential surface of the shaft insertion hole of the rotating body, Is supplied to the gap of the thrust bearing formed between each end surface of the rotating body and the thrust bearing surface of the shaft unit and then exhausted and used to form the gas film in the clearance between the thrust bearings, It is not necessary to separately provide a groove and a hole for ejecting the compressed gas, and a thrust bearing surface for ejecting the compressed gas to the clearance between the thrust bearings. Further, since the shaft unit for non-contact supporting the rotating body is fixed at both ends, even if the shaft unit is long in correspondence with the size of the rotating body, the warping can be suppressed and contact between the rotating body and the shaft unit can be prevented . Therefore, it is possible to realize a both-end support type constant-pressure gas bearing unit capable of supporting a rotating body rotating at a high speed with a simple structure and in a more non-contactable manner stably.

1 is an external view (without a pulley 2) of an air bearing unit 4 of a both end support type according to one embodiment of the present invention.
Fig. 2 is a side view of the air bearing unit 4 of both end support type in which the pulley 2 is assembled, according to one embodiment of the present invention.
3 (A) is a front view of the pulley 2, and Fig. 3 (B) is a sectional view taken along the line AA of Fig. 3 (A).
4 is a developed view of the parts of the air shaft unit 1 according to the embodiment of the present invention.
5 (A) is a front view of the air shaft 11, and Fig. 5 (B) is a sectional view taken along the line BB of Fig. 5 5D is an enlarged partial cross-sectional view of the radial bearing portion 114. FIG.
6 (A) is a front view of the thrust plate 12, and FIG. 6 (B) is a CC sectional view of FIG. 6 (A).
7 is a diagram schematically showing the state of support of the pulley 2 during supply to the air shaft 11. Fig.

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

First, the overall structure of both end-support type static-pressure gas bearing units according to this embodiment will be described. Here, an air bearing unit 4 of both end support type suitable for noncontact support of a rotary body having a long length in the axial direction O, such as a pulley 2 for sending a wire material such as an optical fiber or carbon fiber, .

Fig. 1 is an external view of the both end support type air bearing unit 4 according to the present embodiment. Fig. 2 is a plan view of the air bearing unit 4 of the both end support type in which the pulley 2, Side view.

As shown in the figures, the air bearing unit 4 of both ends of the present embodiment has an air shaft unit 1 for rotatably and non-contacting the pulley 2 having a long length in the direction of the axis O, And two shaft holders 3A and 3B for supporting the air shaft unit 1 at both ends thereof.

As will be described later, the air shaft unit 1 is an assembly of the air shaft 11, the thrust plate 12 and the nut 13 (see Fig. 4), and the pulley 2 is an assembly of the pulley 2 After the air shaft 11 (the radial bearing portion 114 formed with the porous sintered layer 112) is inserted into the air shaft insertion hole 22 formed in the direction of the thrust plate 12, Contact with the air shaft unit 1 by tightening the nut 13 (the screw portion 1151 of the rod portion 115) and the nut 13. [

On the other hand, the two shaft holders 3A and 3B are provided on a pedestal such as a granite surface plate, for example, And are fixed so as to face each other at intervals. Each of the shaft holders 3A and 3B includes an end portion (the thrust plate 12 and the base portion 113 of the air shaft 11) of the air shaft unit 1 whose axial center O is directed substantially parallel to the pedestal, Is held at a position corresponding to the maximum diameter of the pulley 2. [

Each of the shaft holders 3A and 3B includes a lower block member 33 having a flange 35 fixed to the pedestal by bolts and a lower block member 33 having a flange 35 fixed to the upper block member 33, And has two bolts 34 for adjusting the distance t1 between the upper surface of the lower block member 33 and the bottom surface of the upper block member 33. [ Grooves having a semicircular cross section are formed in the thickness t2 direction on the upper surface of the lower block material 33 and the bottom surface of the upper block material 32, And a shaft fixing hole 31 is formed at a height position. The two bolts 34 are fastened to the screw holes of the lower block member 33 through the bolt holes of the upper block member 33 at positions on both sides of the shaft fixing hole 31. [

(The thrust plate 12 and the base portion 113 of the air shaft 11) of the air shaft unit 1 are inserted into the shaft fixing holes 31 of the two shaft holders 3A and 3B arranged opposite to each other The spacing t1 between the lower block member 33 and the upper block member 32 is narrowed by tightening the two bolts 34 of the shaft holders 3A and 3B and the air shaft unit 1 (The thrust plate 12 and the base portion 113 of the air shaft 11) are fixed. Thereby, the pulley 2 assembled to the air shaft unit 1 is rotatably held in the non-contact state around the axis O at the position of the predetermined height.

In the present embodiment, two shaft holders 3A and 3B for adjusting the gap t1 between the lower block member 33 having the flange 35 and the upper block member 32 with two bolts 34, Any type of shaft holder may be used as long as the air shaft unit 1 can be held by both end portions thereof (the thrust plate 12 and the base portion 113 of the air shaft 11).

Next, the pulley 2 and the air shaft unit 1 that rotatably supports the pulley 2 around the axis O will be described.

3 (A) is a front view of the pulley 2, and Fig. 3 (B) is a sectional view taken along the line A-A in Fig. 3 (A).

As shown in the figure, the pulley 2 to be supported has a substantially cylindrical shape with a longer length in the direction of the axis O than the diameter r2, and on the outer peripheral surface 23 thereof, Wire material) is placed. The pulley 2 is provided with an air shaft insertion hole 22 penetrating from the one end face 25A to the other end face 25B at the position where the axis O passes. A radial bearing portion 114 having a porous sintered layer 112 of the air shaft 11 is slidably inserted in the air hole 22 for inserting the air shaft.

Bosses 24A and 24B surrounding the hole 22 for inserting the air shaft are formed on both end faces 25A and 25B of the pulley 2. [ The end faces 241A and 241B of the bosses 24A and 24B are flatly finished. In the air bearing unit 4 in the state where the pulley 2 is assembled (the state shown in Fig. 2), the end face 241A of one boss 24A has a slight gap (thrust bearing gap) And the end surface 241B of the other boss 24B faces the thrust plate 12 with a slight gap (thrust bearing gap) (Thrust bearing surface) 121 (see Figs. 5 and 6).

As shown in the figure, ring-shaped flange portions 21 projecting in the radial direction from the outer peripheral surface 23 may be formed at both ends of the pulley 2. [

4 is a part development view of the air shaft unit 1. Fig.

As shown in the figures, the air shaft unit 1 is inserted into the air shaft insertion hole 22 of the pulley 2, and the air shaft 2 is rotatably supported on the air shaft (not shown) A thrust plate 12 for preventing the pulley 2 from dropping off from the air shaft 11 and a nut 13 for fixing the thrust plate 12 to the air shaft 11 are provided.

5 (A) is a front view of the air shaft 11, and Fig. 5 (B) is a sectional view taken along the line BB of Fig. 5 5D is an enlarged partial cross-sectional view of the radial bearing portion 114. FIG.

As shown in the figure, the air shaft 11 has a cylindrical back metal 111 having a stepped portion and an outer peripheral surface of a middle portion (radial bearing portion) 114 of the back metal 111, And a porous sintered layer (112) formed on the porous sintered body (1142).

The back metal 111 has a base portion 113 having a diameter substantially equal to the outer diameter of the bosses 24A and 24B of the pulley 2, a radial bearing portion 114 having a diameter smaller than that of the base portion 113, And a rod portion 115 having a diameter smaller than that of the bearing portion 114 are integrally provided.

An air passage 116 is formed in one end face 1131 of the base portion 113 from the end face 1131 to the inside of the radial bearing portion 114 through the inside of the base portion 113 . A coupler 40 (see Fig. 2) for connecting the pump air supply tube 41 is screwed into an opening (supply mechanism) 117 of the air flow path 116 on one end surface 1131 A threaded portion 118 is formed.

The base portion 113 is extended from one shaft holder 3A to a position where the other end face 1132 protrudes from the shaft fixing hole 31 of the one shaft holder 3A to the other shaft holder 3B side, And is inserted into the shaft fixing hole 31 of the holder 3A (see Fig. 2). In this state, the two bolts 34 of the one shaft holder 3A are tightened, whereby the base portion 113 is fixed in the shaft fixing hole 31 of one shaft holder 3A .

The radial bearing portion 114 is integrally formed on the other end surface (a step surface that functions as a thrust bearing surface) 1132 of the base portion 113 and the outer peripheral surface 1142 of the radial bearing portion 114, A porous sintered layer 112 having air permeability is formed in the entire region of the porous sintered body 112. A plurality of ring-shaped grooves 1143 located at the boundary with the porous sintered layer 112 are formed in the peripheral surface 1142 of the radial bearing portion 114 in the circumferential direction, At the bottom, a hole 1144 is formed which leads to the air passage 116, respectively. Thus, when the supply of air from the air supply pipe 41 of the pump connected to the air supply mechanism 117 is started, the compressed air sent from the pump flows through the air flow path 116 and the hole 1144 into the radial bearing portion Shaped sintered layer 1143 which is provided in the circumferential direction ring grooves 1143 located on the outer peripheral surface 1142 of the porous sintered layer 112 and passes through the pores in the porous sintered layer 112 to function as a radial bearing surface 112 from the outer circumferential surface 1121 thereof.

The number and layout of the ring-shaped grooves 1143 located on the outer peripheral surface 1142 of the radial bearing portion 114 are appropriately adjusted so that the compressed air is uniformly ejected from the entire outer peripheral surface 1121 of the porous sintered layer 112 It is good. For example, the number of the ring-shaped grooves 1143 corresponding to the length (the width of the porous sintered layer 112) t4 of the radial bearing portion 114 can be set in the direction of the axis O of the porous sintered layer 112 As shown in Fig. Further, the radial bearing portion 114 is spaced apart from the center position (the inner side position by t4 / 2 from one end of the radial bearing portion 114) toward the base portion 113 side and the rod portion 115 side Shaped groove 1143 may be formed at a position where the entire pressure of the radial bearing gap 60 can be maintained at a high level.

The radial bearing portion 114 in which the porous sintered layer 112 is formed is inserted into the hole 22 for inserting the air shaft of the pulley 2. [ The outer diameter R1 of the radial bearing portion 114 including the porous sintered layer 112 is smaller by a predetermined dimension than the inner diameter r1 of the hole 22 for inserting the air shaft of the pulley 2 It is designed. Therefore, when the radial bearing portion 114 is inserted into the air shaft insertion hole 22 of the pulley 2, the inner peripheral surface 221 of the air shaft insertion hole 22 and the outer peripheral surface of the radial bearing portion 114 (Radial bearing surface) 1121 of the porous sintered layer 112 formed on the radial bearing gap 1142 (see Fig. 7). After starting the supply of air from the pump to the air shaft 11, compressed air ejected from the outer peripheral surface (radial bearing surface) 1121 of the porous sintered layer 112 forms a high-pressure air film on the radial bearing clearance 60 . The radial load is supported by the pressure of the air film.

The length t4 of the radial bearing portion 114 (the distance between the stepped surfaces 1132 and 1141) is set to be the same as the length of the end faces 241A and 241B of the bosses 24A and 24B on both end faces 25A and 25B of the pulley 2. [ (The length of the pulley 2) (t3). The end face 241A of one of the bosses 24A of the pulley 2 inserted into the radial bearing portion 114 and the other end face 24A of the boss 24A inserted into the radial bearing portion 114 (Radial bearing portion 114 and base portion 113) and a radial bearing gap 60 is formed between the radial bearing gap 114 and the radial bearing gap 1132, which is a stepped surface that functions as a thrust bearing surface. A thrust bearing gap 61a is formed. Similarly, the end face 241B of the other boss 24B of the pulley 2 and the end face of the radial bearing portion 114 (the end formed by the radial bearing portion 114 and the outer portion of the rod portion 115) A thrust bearing gap 61b which is connected to the radial bearing gap 60 is provided between one end surface 121 of the thrust plate 12 which functions as a thrust bearing surface, (See Fig. 7). It is preferable to improve the assembling precision of the thrust plate 12 by finishing the edge portion 11411 of the end surface 1141 of the radial bearing portion 114 so as not to blunt to prevent the occurrence of the self-excited vibration.

The rod portion 115 is formed continuously with the end surface 1141 of the radial bearing portion 114 and is inserted into the shaft insertion hole 123 of the thrust plate 12 to be described later. A screw portion 1151 screwed to the nut 13 is formed at the tip of the rod portion 115.

6 (A) is a front view of the thrust plate 12, and Fig. 6 (B) is a cross-sectional view taken along line C-C of Fig. 6 (A).

As shown in the figure, the thrust plate 12 has a cylindrical shape with an outer diameter substantially equal to the outer diameter of the base portion 113 of the air shaft 11, and has one end face 121 The shaft insertion hole 123 is formed so as to penetrate from the first surface 122 to the second surface 122. In the shaft insertion hole 123, the rod portion 115 of the air shaft 11 is inserted.

On the other hand, the air shaft unit 1 having the above configuration can be assembled as follows.

First, the pulley 2 is assembled to the air shaft unit 1. More specifically, the air shaft 11 is inserted into the air shaft insertion hole 22 of the pulley 2 so that the radial bearing portion 114 formed with the porous sintered layer 112 is positioned in the air shaft insertion hole 22 of the pulley 2, The air shaft 11 into which the pulley 2 is inserted is inserted into the thrust plate 12 so that the rod portion 115 is positioned in the shaft insertion hole 123 of the thrust plate 12. Then, Into the shaft insertion hole 123 of the shaft 12. In this state, when the nut 13 is fastened to the threaded portion 1151 formed at the tip of the rod portion 115, one end face 121 of the thrust plate 12 is fixed to the radial bearing portion 114 and the rod (The end face of the radial bearing portion 114) 1141 formed by the external radial difference of the radial bearing portion 115. [

Thereafter, the shaft center O of the air shaft unit 1 in which the pulley 2 is assembled is oriented substantially parallel to the pedestal, and the both ends (the thrust plate 12, the air shaft 11, Base portion 113) are fixed to the two shaft holders 3A, 3B arranged at a predetermined interval (see Fig. 2). More specifically, the other end surface (stepped surface serving as a thrust bearing surface) 1132 of the base portion 113 of the air shaft 11 is engaged with the shaft fixing hole 31 of one shaft holder 3A The base portion 113 of the air shaft 11 is inserted into the shaft fixing hole 31 of one of the shaft holders 3A so as to protrude to the other shaft holder 3B side, The thrust plate 12 is formed so as to protrude from one of the shaft fixing holes 31 of the other shaft holder 3B to one shaft holder 3A side, Is inserted into the shaft fixing hole 31 of the other shaft holder 3B. The base portion 113 of the air shaft 11 and the thrust plate 12 are engaged with the shaft holders 3A and 3B of the shaft holders 3A and 3B by tightening the two bolts 34 of the shaft holders 3A and 3B in this state. And is fixed in the shaft fixing hole 31.

Since the length t4 of the radial bearing portion 114 is longer than the length t3 of the pulley 2 by a predetermined dimension as described above, the cross section of the boss 24A of the pulley 2 (Thrust bearing surface) 1132 of the base portion 113 and the other end surface (thrust bearing surface) 1132 of the base portion 113 and the end surface of the other boss 24B of the pulley 2 A thrust bearing gap 61b is formed between one end surface (thrust bearing surface) 121 of the thrust plate 12 and one end surface (thrust bearing surface) Compressed air discharged from the radial bearing clearance 60 flows into these thrust bearing gaps 61a and 61b, and a high-pressure air film is formed. The thrust load is supported by the pressure of the air film.

Here, the length t4 of the radial bearing portion 114 is set such that the thickness s1 (see Fig. 7) of the thrust bearing gaps 61a and 61b on both sides of the pulley 2 does not generate self- Is set to be larger than the thickness (s2) of the base material (60). Here, the thrust bearing gaps 61a and 61b having the thickness s1 not to generate the self-excited vibrations are slightly shifted in the thrust direction in the pulley 2 in the no-load state, 61b are so wide that they can not be suddenly pushed back toward the other thrust bearing surfaces 121, 1132 even if they are slightly closer to the one thrust bearing surface 1132, 121 side. For example, when the outer diameter of the bosses 24A and 24B of the pulley 2 is about 22 mm and the thickness of the radial bearing gap 60 is about 9 to 10 占 퐉, the thicknesses s1 and s2 of the thrust bearing gaps 61a and 61b The length t4 of the radial bearing portion 114 is set to be about 22.5 to 37 mu m and the flow rate of the compressed air of the supply air pressure of 0.5 Mpa is adjusted to the open flow rate of 520 NL / hr or less, The occurrence of vibration is prevented.

Next, the supporting state of the pulley 2 during supply to the air shaft 11 will be described.

7 is a diagram schematically showing the support state of the pulley 2 during air supply to the air shaft 11. Fig.

As shown in the figure, in the air bearing unit 4 in the state in which the pulley 2 is assembled (Fig. 2), the pump air supply mechanism (not shown) is connected to the air supply mechanism 117 of the air shaft 11 And the compressed air f is supplied to the radial bearing portion 114 through the air passage 116 and the hole 1144 of the air shaft 11 Shaped grooves 1143 located on the outer circumferential surface 1142 and is ejected into the radial bearing clearance 60 from the outer circumferential surface (radial bearing surface) 1121 of the porous sintered layer 112. Therefore, a high-pressure air film is formed in the radial bearing gap 60, and the radial load is supported by the pressure. As a result, the movement of the pulley 2 in the radial direction is restricted.

The compressed air f in the radial bearing gap 60 is directed to one end surface (thrust bearing surface) of the thrust plate 12 along the outer peripheral surface (radial bearing surface) 1121 of the porous sintered layer 112, (Thrust bearing surface) 1132 side of the base 121 and the other end surface (thrust bearing surface) 1132 side of the base portion 113. The end surface 241A of one boss 24A of the pulley 2 and the end surface The thrust bearing gap 61a between the thrust bearing surface 1132 of the thrust plate 12 and the end surface 241B of the other boss 24B of the pulley 2 and one end surface Thrust bearing surface) 121 in the thrust bearing gap 61b.

The compressed air f1 flowing into the thrust bearing gaps 61a and 61b radially flows toward the outer periphery of each of the bosses 24A and 24B and finally discharged to the outside (atmospheric pressure). The pressure in each of the thrust bearing gaps 61a and 61b is higher on the inner circumferential side of the pulley 2 into which the compressed gas f1 discharged from the radial bearing gap 60 flows and the outer periphery of the bosses 24A and 24B As shown in Fig. Therefore, an air film having a high average pressure is formed in the thrust bearing gaps 61a and 61b, and the thrust load is supported by the pressure. This restrains the movement of the pulley 2 in the thrust direction.

When the thickness s1 of the thrust bearing gaps 61a and 61b is small and the pulley 2 moves slightly along the axis O, one of the thrust bearing gaps 61a and 61b becomes narrow, The thrust bearing clearances 61b and 61a on the side of the thrust bearing gap 61a and 61b become thicker, so that the pressure distribution in the thrust bearing clearances 61a and 61b is changed, and there is a possibility that the self-excited vibration is generated. Specifically, in the narrowed thrust bearing gaps 61a and 61b, the pressure rises due to the increase of the resistance. In the thrust bearing gaps 61b and 61a that are widened, the pressure decreases due to the decrease in resistance. The bearing member 2 moves along the axis O so as to be pushed back toward the other of the thrust bearing surfaces 121 and 1132 only slightly closer to one of the thrust bearing surfaces 1132 and 121. This is repeated.

In the present embodiment, even if the pulley 2 is slightly moved to one of the thrust bearing surfaces 1132 and 121, there is a sufficient margin that the pulley 2 can not be pushed back to the other thrust bearing surfaces 121 and 1132 side Since the thrust bearing gaps 61a and 61b having the thickness s1 are provided, generation of self-excited vibrations can be suppressed.

As described above, according to the air bearing unit 4 of the present embodiment, compressed air is supplied from the porous sintered layer 112 opposed to the inner peripheral surface 221 of the pulley 2 to the radial bearing clearance 60, Since the compressed air exhausted from the radial bearing gap 60 is introduced into the thrust bearing gaps 61a and 61b on both sides of the pulley 2 while maintaining the pressure thereof, The radial load and the thrust load of the pulley 2 can be supported in a noncontact manner by the pressure of the air film in the pressure and thrust bearing gaps 61a and 61b. Therefore, since the power loss hardly occurs, the pulley 2 can be rotated at a high speed. Since the compressed air exhausted from the radial bearing gap 60 is used for forming the air film in the thrust bearing gaps 61a and 61b, the exhaust groove for exhausting the compressed air from the radial bearing gap 60 It is not necessary to form an exhaust hole in either of the air shaft unit 1 and the pulley 2. [ Therefore, the structure of the air bearing unit 4 holding the pulley 2 rotating at a high speed can be simplified.

Since the porous sintered layer for ejecting the compressed air to the thrust bearing gaps 61a and 61b need not be additionally provided in the air shaft 11, the structure of the air bearing unit 4 can be further simplified , The manufacturing cost of the air bearing unit 4 can be reduced.

Since the air shaft unit 1 is held at both ends thereof, even if the air shaft 11 is long to hold the long pulley 2, the air shaft 11 can be prevented from being deflected by its own weight can do. The inner peripheral surface 221 of the air shaft insertion hole 22 of the pulley 2 and the outer peripheral surface (radial bearing surface) 1121 of the porous sintered layer 112 opposed to each other with a slight radial bearing gap 60 Can be prevented. Therefore, even if the pulley 2 to be supported is elongated in the direction of the axis O, the pulley 2 can be stably and noncontactually supported.

Further, since it is not necessary to form the exhaust hole along the axis O in the pulley 2, the thickness of the pulley 2 can be made thinner. Therefore, even if the pulley 2 is elongated in the direction of the axis O, the pulley 2 can be made thinner and the weight of the pulley 2 can be reduced. As a result, the pulley 2 having a longer length can be rotated at a higher speed, and the load applied to the air shaft 11 is reduced, so that warping of the air shaft 11 is further suppressed. Therefore, the pulley 2 rotating at a high speed can be more stably contactlessly supported.

In the air bearing unit 4 according to the present embodiment, it is sufficient if the compressed air is ejected from the radial bearing surface 1121 to the radial bearing gap 60, and the thrust bearing surfaces 1132, 121 and the radial bearing surface It is not necessary to mount a thick porous body for ejecting the compressed gas from each of the plurality of openings 1121. Therefore, it is sufficient if the porous sintered layer 112 having a thickness of several millimeters (for example, about 2.5 mm) is formed integrally with the back metal 111. Therefore, the air bearing unit 4 can be made compact.

Since the porous sintered layer 112 is formed on the air shaft 11 side according to the air bearing unit 4 according to the present embodiment, the pulley 2 to be supported is provided with the air shaft 11 It is sufficient that the hole 22 for inserting the air shaft for insertion is formed, and it is not necessary that a special portion is formed. Therefore, the manufacturing cost of the pulley 2 as a replacement part can be reduced, and the running cost can be reduced.

Further, since the thickness s1 of the thrust bearing gaps 61a and 61b is made large enough not to cause self-excited vibration, occurrence of self-excited vibrations can be prevented. Therefore, the pulley 2 rotating at a high speed can be more stably contactlessly supported.

In this embodiment, the cylindrical back metal 111 having a stepped portion is used. However, the back metal 111 may have a hollow structure, for example.

As described above, in the present embodiment, the air bearing unit 4 that supports the pulley 2 having a long length is taken as an example, but it is also possible to support the rotating body other than the pulley 2 having a long length. For example, a plurality of normal pulleys may be supported.

[Industrial applicability]

INDUSTRIAL APPLICABILITY The present invention can be used as both end support type air bearing units suitable for noncontact support of a rotating body such as a pulley for sending wire materials such as optical fibers and carbon fibers.

1: Air shaft unit,
2: pulley,
3A, 3B: Shaft holder,
4: Air bearing unit,
11: Air shaft,
12: thrust plate,
13: Nut,
21: flange portion,
22: hole for inserting air shaft,
23: outer circumference of the boss,
24A and 24B: bosses,
25A, 25B: end face of the pulley,
111: Back metal,
112: porous sintered layer,
113: base portion,
114: Radial bearing part,
115:
116: By ventilation,
117:
118: threaded portion,
121: cross-section of thrust plate (thrust bearing surface),
122: cross-section of thrust plate,
123: hole for shaft insertion,
221: inner circumference of the pulley,
241A, 241B: cross-section of the boss,
1121: outer peripheral surface (radial bearing surface) of the porous sintered layer,
1131: cross section of base portion,
1132: Cross section of the base portion (step surface, thrust bearing surface)
1141: Cross section (stepped surface) of the radial bearing part,
1142: outer peripheral surface of the radial bearing portion,
1143: ring shaped groove,
1144: hole,
1151:

Claims (4)

A static-pressure gas bearing unit for supporting a rotating body rotating in the direction of a circumference of a shaft by a gas film interposed between a radial bearing clearance and a gap between first and second thrust bearers,
A shaft unit inserted into a shaft insertion hole passing through both end faces of the rotating body;
And shaft holding means for holding the shaft unit at positions on both sides of the shaft insertion hole of the rotating body,
The shaft unit includes:
A radial bearing surface for forming the radial bearing gap between the inner peripheral surface of the shaft insertion hole and the inner peripheral surface and for ejecting a base for forming the gas film in the radial bearing gap,
A first thrust bearing which is adjacent to the radial bearing surface and which is opposite to one end surface of the rotating body and which is connected to one end side of the radial bearing gap, A first thrust bearing surface forming a gap,
And a second thrust bearing gap which is adjacent to the radial bearing surface and which is opposite to the other end surface of the rotating body and which is connected to the other end side of the radial bearing gap, Having a second thrust bearing surface,
The gas,
The radial bearing gap is discharged toward the first thrust bearing gap and the second thrust bearing gap to be exhausted from the radial bearing gap to the first thrust bearing gap and the second thrust bearing gap, And the gas film is formed in the first thrust bearing gap and in the second thrust bearing gap, respectively. The method according to claim 1,
The shaft unit includes:
And a porous layer formed on an outer circumferential surface of the radial bearing portion and having a stepped portion having a radial bearing portion having a diameter smaller than that of the base portion formed on an end surface of the base portion, And the radial bearing surface is formed between the base portion and the radial bearing portion between the radial bearing portion and the inner peripheral surface of the shaft insertion hole of the rotating body, A shaft for forming the first thrust bearing gap between the one end surface of the rotating body and the stepped surface of the thrust bearing surface as the first thrust bearing surface,
And a second thrust bearing surface that is fixed to an end surface of the radial bearing portion and faces the other end surface of the rotating body as the second thrust bearing surface, And a thrust plate which forms the thrust plate,
Wherein the shaft holding means comprises:
And the thrust plate is fixed to the base portion of the shaft. 3. The method according to claim 1 or 2,
Wherein the rotating body has a pulley having a dimension in the axial direction longer than a dimension in the radial direction. A shaft unit used in the hydrostatic bearing unit as a component of the hydrostatic bearing unit according to any one of claims 1 to 3.
KR20157005284A 2012-08-10 2013-07-22 Gas-static bearing unit KR20150038502A (en)

Applications Claiming Priority (3)

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JPJP-P-2012-178123 2012-08-10
JP2012178123A JP2014035054A (en) 2012-08-10 2012-08-10 Static pressure gas bearing unit
PCT/JP2013/069767 WO2014024666A1 (en) 2012-08-10 2013-07-22 Gas-static bearing unit

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TW201420907A (en) 2014-06-01
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WO2014024666A1 (en) 2014-02-13
JP2014035054A (en) 2014-02-24

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