JP2001208062A - Porous hydrostatic bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrostatic bearing of high strength, a few expensive porous material, and compactness. SOLUTION: A radial bearing member 55, rotatably retaining outer surface of a revolving shaft having a flange 51 projecting to diameter direction, is fitted and fixed to an inner surface of a housing 50 by laying plurality of porous ring members 53 and nonporous ring members 54 of the same outer and inner diameters by turns to axial direction as the non-porous ring members occupy the both ends. A thrust bearing member 58 retaining the thrust face of the flange 51 is formed by laying porous ring member 60 on a face opposing to the above thrust face of the nonporous ring member 59.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supplying a compressed gas between an outer diameter surface of a rotating shaft and a bearing surface of a bearing member made of a porous member to form a film of gas to make the rotating shaft float. TECHNICAL FIELD The present invention relates to a porous hydrostatic bearing that is rotatably supported by a bearing.

[0002]

2. Description of the Related Art As a conventional porous hydrostatic bearing of this kind,
There is one as shown in FIG. This is a substantially cylindrical sleeve 20 on the inner surface 1b of the housing 1.
Are elastically supported via two O-rings 3, 3 provided in grooves provided at both ends of the outer diameter surface of the sleeve 20, respectively. The sleeve 20 is formed by integrally joining four sleeve members 20A to 20D having the same outer diameter, and has a plurality of radial bearings 4, 4 made of a porous member on the inner surface and a pair of thrust bearings 12, 12, Is installed and mounted. A hollow shaft 5 is provided at the axial center of the housing 1 with the respective radial bearing 4 and thrust bearing 1.
2 is rotatably mounted via a small gap (not shown).

A single air supply hole 6 is formed in the body of the housing 1 so as to extend from the outer surface 1a of the housing to the inner surface 1b. The outer diameter surface 20a of the sleeve 20 is the housing 1
2 O-rings 3 between the both sides with a smaller diameter than the inner diameter surface 1b
An air supply chamber 21 composed of an annular space sealed by 3 is provided. The cylindrical sleeve member 20A which is a constituent member of the sleeve 20 is provided with an annular concave portion 22 having a larger diameter than the central portion at the axial end portion of the inner diameter surface, and two radial bearings 4 in the annular concave portion 22. Are fixedly attached. The two radial bearings 4, 4 fixed to one sleeve member 20A at a distance in the axial direction have their bearing surfaces 4a simultaneously machined to ensure coaxiality.

[0004] A shallow circumferential groove is formed as an air supply chamber 24 on the outer diameter surface of each radial bearing 4, and an air supply hole 25 communicating the two air supply chambers 21, 24 penetrates through the sleeve member 20 A in the radial direction. Is provided. On the other hand, the shaft 5 has an exhaust hole 7 located between the two radial bearings 4 and 4 and communicating with the hollow shaft hole 5 a provided in the shaft center of the shaft 5 from the shaft outer peripheral surface.
Is provided, and the compressed gas ejected from the bearing surface of the radial bearing 4 is exhausted from the exhaust hole 7.

Each of the pair of thrust bearings 12, 12 for restraining the shaft 5 in the thrust direction has one radial bearing 4.
The axial thrust surfaces 11, 11 of the flange portion 10 protrudingly provided at one end of the shaft 5 are sandwiched between the axially separated thrust surfaces.

That is, one thrust bearing 12 is fitted and attached to a concave portion provided on the inner diameter surface of the annular sleeve member 20B. The sleeve member 20B is fixed to one end of the sleeve member 20A, and the shaft 5 is fitted to the radial bearing 4. An annular sleeve member 2 having a thickness obtained by adding a pair of thrust bearing clearances to the thickness of the flange portion 10 of the shaft 5.
OC is fixed to the end surface of the sleeve member 20B, and another sleeve member 20D is further fixed to the end surface of the sleeve member 20C. The sleeve member 2D is provided with the sleeve member 2 described above.
0B and the other thrust bearing 1
2 are fitted and fixed, and one thrust bearing and the other thrust bearing are separated in the axial direction.

The sleeve member 20B and the sleeve member 20D
Are provided with air supply ports 30 in the radial direction from the outer diameter surface to the thrust bearing 12. A flat bearing surface 12 a of the thrust bearing 12 is provided on the flange portion 10 of the shaft 5.
Exhaust holes 31 are provided in the radial direction and the axial direction, respectively, for exhausting the compressed gas ejected from the nozzle.
Communicates with the hollow shaft hole 5a.

The means for fixing the sleeve members 20A to 20D to each other may be any of screwing, bonding, welding and the like, and the sleeve 20 is a rigid body. Thus, the thrust bearing 12 in which the bearing surface 12a of the thrust bearing 12 is opposed to the thrust surface 11 of the flange portion 10 of the shaft via the bearing gap is formed integrally with the radial bearing 4, and supports the shaft 5 in the radial and thrust directions. A static pressure bearing block is formed. O-rings 33, 33 are arranged on both end surfaces of the hydrostatic bearing block, and inserted into the inner diameter surface of the housing 1. Then, a lid 32 is attached to one end of the housing 1 and fixed.

According to this, two radial bearings 4, 4
And a pair of thrust bearings 12 and 12 are integrally fixed to a substantially integral sleeve 20 and mounted on the housing 1 to assemble them, so that assembly and adjustment of each bearing can be easily performed. I have.

[0010]

However, a relatively axially long radial bearing 4 made of a porous member is incorporated into the inner diameter of a substantially integral sleeve 20 and the inner diameter is used as a bearing surface. Therefore, at the same time as the radial dimension is increased, the strength of the bearing member made of a porous member is low, so that high bearing strength cannot be obtained, and a large-sized porous member is required. Was expensive.

An object of the present invention is to eliminate the disadvantage that not only the above-mentioned bearing parts are expensive in price, but also that they are weak in strength, to reduce the strength and strength of expensive porous materials, It is still another object of the present invention to provide a porous hydrostatic bearing which can be reduced in size by keeping the radial dimension of the radial bearing portion small.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a porous hydrostatic bearing for supporting a rotating shaft, comprising: a housing constituting the outside of the bearing; A radial bearing member in which a plurality of ring-shaped members and non-porous ring-shaped members are alternately stacked in the axial direction and integrally formed, are fitted and fixed to the housing, and rotatably support the outer diameter portion of the rotating shaft. And a gas passage configured to supply a compressed gas from the air supply hole provided in the housing to the porous ring-shaped member.

As a result, the amount of the porous bearing member, which is expensive in price, is reduced, and since there is a bearing surface formed of a non-porous ring-shaped member between the porous ring members, the strength is increased. Since the quality and the non-porous ring-shaped member are directly fitted and fixed to the housing, the dimension in the radial direction can be reduced.

It is preferable that a non-porous ring-shaped member is disposed at both ends of the radial bearing member.
In a porous hydrostatic bearing for supporting a rotating shaft having a radially protruding flange portion, a non-porous ring-shaped member fixed to the housing is opposed to the thrust surface of the flange portion so as to face the thrust surface of the flange portion. It is preferable to use a thrust bearing member in which a porous member is arranged in a plane to be formed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. A ring-shaped member 53 made of a porous material such as bronze, carbon, or ceramics rotatably supports an outer diameter portion of a rotating shaft 52 having a flange portion 51 on an inner diameter surface of the housing 50 formed of the housing members 50A to 50C. Three sets of radial bearing members 55, 55, 55 each formed by alternately stacking a plurality of ring-shaped members 54 made of a non-porous material such as a steel material in the axial direction are fitted and fixed by cold fitting or the like.

In each radial bearing member 55, the non-porous ring members 54 are positioned at both ends in the axial direction, and the porous ring members 53 and the non-porous ring members 54 are alternately arranged in the axial direction. The housing 50 is integrated by screwing, bonding, welding, or the like, and the outer diameter is ground to a predetermined size, and is fitted and fixed to the inner diameter surface of the housing 50 by cold fitting or the like as described above. Each of the porous ring members 53 and the non-porous ring members 54 are successively fitted and fixed to the inner surface of the housing 50 by cold fitting or the like.
5 may be formed. A radial bearing surface 56 is formed by grinding the inner diameter surface of the radial bearing member 55 fitted and fixed to the housing 50 to a predetermined size as described above.

A ring-shaped concave portion 57 is provided on the end surfaces of the housing members 50A and 50C facing the thrust surface of the flange portion 51 of the rotary shaft 52, and a thrust bearing member 58 is mounted in the concave portion 57 by a bolt (not shown). Have been. The thrust bearing member 58 is made of a non-porous material such as steel, and as shown in FIG. 2, a ring-shaped non-porous ring-shaped member 59 and a circumferentially extending non-porous ring-shaped member 59. Porous members 60 equally arranged along
It consists of

The porous member 60 is attached to the hole of the non-porous ring-shaped member 59 by bonding or welding, or is sintered in the hole to form the porous member 60 and at the same time as the non-porous ring-shaped member. 59. The surface of the porous member 60 facing the thrust surface of the flange portion 51 is formed flush with the surface of the non-porous ring-shaped member 59, and forms a thrust bearing surface 61.

The housing 50 has housing members 50A to 50C integrally attached thereto by bolts or the like (not shown). Each radial bearing member 55 passes through air supply holes 63 and 64 from an air supply hole 62 provided on the outer surface of the housing 50.
Annular chambers 6 that are respectively opened on the outer diameter surface of the porous ring-shaped member 53 and the back side of the porous member 60 of the thrust bearing member 58.
5 and 66, and subsequently from the porous ring-shaped member 53 and the porous member 60, between the respective bearing surfaces 56, 61 and the outer diameter surface of the rotating shaft 52, from δ, and from the thrust surface of the flange portion 51, from α, Gas passages are provided to communicate with the exhaust holes 71 on the outer surface of the housing 50 from the exhaust passages 69 and 70 via the respective gas reservoirs 67 and 68. In FIG. 1, a left end and a right end of δ between the left and right radial bearing members 55 are open to the atmosphere.

Next, the operation of the porous hydrostatic bearing configured as described above will be described. The compressed gas introduced into the housing 50 as shown by the arrow a is supplied to the supply passages 63 and 6.
4 and enters the annular chambers 65 and 66 from the porous ring-shaped member 53 of the radial bearing member 55 and the porous member 60 of the thrust bearing member 58, respectively, in the radial and thrust bearing surfaces 56 and 61 and outside the rotary shaft 52. Guided between the radial surface and the thrust surface by δ and α, a gas film is formed to rotatably support the rotating shaft 52, and then from the gas reservoirs 67 and 68 through the exhaust passages 69 and 70 to the exhaust holes 7.
1 is discharged out of the housing 50.

Each of the radial bearing members 55 generates a predetermined static pressure at a portion surrounded by the inner ends of two non-porous ring-shaped members 54 disposed at both ends. Therefore, even if the axial dimension of the two porous ring members 53 is reduced, the static pressure can be generated over a wide range by increasing the axial dimension of the non-porous ring member 54 between them. Can be. Since each non-porous ring-shaped member 54 is formed flush with the surface of the porous ring-shaped member 53, it receives a bearing load together with the porous ring-shaped member 53. Is
Since the mechanical strength is higher than that of the porous ring-shaped member 53, the bearing strength of the radial bearing member 55 can be increased.

Also, the thrust bearing member 58 has a high bearing strength like the radial bearing member 55 because the surface of the non-porous ring-shaped member 59 and the surface of the porous member 60 are formed flush with each other. ing.

In the above-described embodiment, an example in which the non-porous ring-shaped members 54 are arranged at both ends of the radial bearing member 55 has been described. According to this, there is an advantage that the non-porous ring-shaped member 54 can protect the porous ring-shaped member 53 when manufacturing and assembling the main bearing and when assembling the rotating shaft 52 to the main bearing. However, from the functional aspect of the present bearing, the non-porous ring-shaped members 54 at both ends can be omitted.

[0024]

As described above, according to the first aspect of the present invention, it is possible to eliminate the disadvantages of frying at the beginning and to use a small amount of a porous material which is strong in strength and expensive, and particularly has a small dimension in the radial direction. It is a compact porous static pressure bearing that is kept small.

According to the third aspect of the present invention, the strength of the thrust bearing can be increased together with the radial bearing. According to the second and fourth aspects of the present invention, the manufacturing and assembly of the porous hydrostatic bearing according to the present invention are provided. In addition, the effect that the rotary shaft can be accurately assembled to the main bearing can be obtained.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a porous hydrostatic bearing showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

FIG. 3 is an axial sectional view of a conventional porous hydrostatic bearing.

[Explanation of symbols]

 Reference Signs List 50 housing 51 flange portion 52 rotating shaft 53 porous ring member 54 non-porous ring member 55 radial bearing member 56 bearing surface 57 recess 58 thrust bearing member 59 non-porous ring member 60 porous member 61 bearing surface 62 supply Air holes 63, 64 Air supply passages 65, 66 Annular chambers 67, 68 Gas reservoirs 69, 70 Exhaust passages 71 Exhaust holes

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuaki Serizawa 2068-3, Ooka, Numazu-shi, Shizuoka Toshiba Machinery Co., Ltd. (72) Inventor Seiji Kimura 2068-3, Ooka, Numazu-shi, Shizuoka Toshiba Machine Co., Ltd. F-term ( Reference) 3J102 AA02 BA03 BA19 CA16 CA19 EA02 EA06 EA18 EA22 FA08

Claims (4)

[Claims] 1. A porous hydrostatic bearing for supporting a rotating shaft, comprising: a housing forming the outer side of the bearing; and a porous ring-shaped member and a non-porous ring-shaped member each having the same inner and outer diameters are alternately arranged in the axial direction. A radial bearing member fitted and fixed to the housing and rotatably supporting the outer diameter portion of the rotary shaft; and a porous ring-shaped member formed from an air supply hole provided in the housing. And a gas passage configured to supply a compressed gas to the member. 2. The porous hydrostatic bearing according to claim 1, wherein the radial bearing member has a non-porous ring-shaped member disposed at both ends. 3. A porous hydrostatic bearing for supporting a rotating shaft having a radially protruding flange portion, comprising: a housing forming the outer side of the bearing; a porous ring-shaped member having the same inner and outer diameters; A radial bearing member, which is integrally formed by alternately stacking a plurality of material ring-shaped members in the axial direction, is fitted and fixed to the housing, and rotatably supports the outer diameter portion of the rotating shaft; and A thrust bearing member in which a porous member is arranged in a plane opposed to the thrust surface of a non-porous ring-shaped member fixed to the housing so as to face the thrust surface; and an air supply hole provided in the housing. And a gas passage configured to supply compressed gas to the porous ring-shaped member and the porous member. 4. The porous hydrostatic bearing according to claim 3, wherein a non-porous ring-shaped member is disposed at both ends of the radial bearing member.