JPH0198710A - Static pressure gas bearing - Google Patents

Abstract

PURPOSE:To attenuate an axial vibration in the radial direction by forming a radial bearing part with a thrust bearing part in one body fixing this bearing member to a frame through a mounting part and providing plural ring shape grooves on the positions avoiding the radial bearing surface or the thrust bearing surface of the bearing member. CONSTITUTION:Ring shape grooves 60 are provided in the positions avoiding the radial bearing surface 511 or the thrust bearing surface 521 of a bearing member 50 consisting of a radial bearing part 51 with a thrust bearing part 52 in one body. Therefore, a mounting part 56 to the frame 58 of the bearing member 50 and the radial bearing part 51 are isolated in view of vibration and an axial vibration in the radial direction propagated from a rotator 54 to the radial bearing part 51 of the bearing member 50 can be attenuated sufficiently. As the radial bearing part 51 and the thrust bearing part 52 of the bearing member 50 are formed in one body and machining on them can be carried out simultaneously, the perpendicularness between the radial bearing surface 511 and the thrust bearing surface 521 can be kept with high precision.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a static device that supports a rotating body having a flange that rotates at high speed in a non-contact manner with gas supplied from an external air supply source such as a compressor. This invention relates to the structure of a pressure gas bearing.

[Conventional technology]

The general structure of this type of conventional static pressure gas bearing is as follows:
The one shown in FIG. 3 is well known.

In FIG. 3, a rotating body 2 having a flange 1 is rotationally driven by a built-in motor 3, and after gas compressed by an air supply source 4 such as a compressor passes through a filter 5 and a regulator 6, gas is supplied from a gas supply lower. Supplied to the bearing section.

The gas bearing portion is a radial bearing member 8. Radial bearing part 8
1 and a thrust bearing part 91, and a thrust bearing member 9 facing the 7 flange 1 of the rotating body 2. The gas supplied from the gas supply port 7 is supplied to the radial bearing member 8. Bearing member 10. and an air supply hole 13a having a minute diameter formed in the thrust bearing member 9,
81g, 91a, and 9a toward the rotating body 2 or its 7 flange 1, and the rotating body 2 is moved to the radial bearing member 8. Bearing member 10. It is supported in a non-contact state with respect to the thrust bearing member 9.

Further, reference numeral 11 denotes an O-ring for sealing the supplied gas, and the outer circumference of the radial bearing member 8 and the bearing member l.
It is fitted into circumferential grooves 8b and 81b formed on the outer periphery of O.

By the way, in the static pressure gas bearing configured as described above, when the rotational speed of the rotor 2 is increased, the axial displacement of the rotor 2 in the radial direction changes as shown in FIG. 4. In other words, as the rotational speed is increased (first, two resonance points 21 and 22 appear at the rotational speeds nl and n2. These resonance points are determined by the weight of the rotating body 2 and the radial bearing member 8. One of these is when the rotating body 2 resonates in a conical mode, and the other is when the rotating body 2 resonates in a parallel mode.Resonance point 21 , 22 correspond to the conical mode or the parallel top mode depends on the shape of the rotating body 2 and the arrangement method of the radial bearing member 8. As the rotation speed increases, the radial axial displacement reaches a certain peak value, but if the balance of the rotating body 2 is kept good, the radial axial displacement will gradually become smaller as the rotational speed is further increased. However, as the rotational speed is further increased, a phenomenon occurs in which the radial axis displacement of the rotating body 2 suddenly increases at a rotational speed n3 that is more than twice the rotational speed nl at which the resonance point 21 appears. This phenomenon is called whirl, and when whirl occurs, the radial shaft displacement does not decrease even if the rotation speed is increased further.
In extreme cases, the rotating body 2 and the radial bearing member 8 will come into contact and cause seizure.7 The ratio ns/n1 of the rotation speed n3 at which this whirl occurs and the rotation speed fil at the resonance point 21 is calculated as the whirl ratio. That's what it means. It is known that the whirl ratio is a number of 2 or more, but in order to stably rotate the rotating body 2 at a higher speed, the whirl ratio needs to be increased.

A well-known method for increasing the whirl ratio is to elastically support the radial bearing member 12 with an O-ring 11, as shown in FIG. This method attempts to attenuate vibrations by the elastic action of the O-ring 10 at the initial stage of whirl generation.

2 of conventional hydrostatic gas bearings applying the above method
Two examples will be explained below based on FIGS. 6 and 7.

B1; FIG. 6 shows a cross section of a bearing member of a hydrostatic gas bearing. In FIG. 6, the bearing member shown in FIG.
1 and a thrust bearing wing. Further, in order to increase the whirl ratio, a QIJ song that also acts as a seal against the supplied gas is fitted into a circumferential groove 31b formed on the outer periphery of the radial bearing portion 31. This O-ring damps the radial shaft vibration propagated from the rotating body U to the radial bearing portion 31 at the initial stage of whirl generation.

(B): FIG. 7 shows a cross section of a bearing member of another hydrostatic gas bearing. Unlike the above example B), the bearing member hammer is divided into a radial bearing member 4 and a thrust bearing member 42.
It is composed of. Furthermore, an O-ring I that acts as a seal against the supplied gas is fitted into a circumferential groove 42b formed in an end surface 421 of the thrust bearing member 42 that contacts the radial bearing member 41. In this example as well, the circumferential groove 41 formed on the outer periphery of the radial bearing member 4
The O-ring 43 fitted in b damps the radial shaft vibration propagated from the rotating body 45 to the radial bearing member 41.

[Problem that the invention seeks to solve]

However, these conventional static pressure gas bearings have the following problems.

That is, in the above example A), the radial bearing portion 31
and the thrust bearing part are integrally formed, and the bearing member (9
) is fixed to a frame (not shown), so I
The radial movement of the radial bearing portion 31 is restricted. Therefore, the radial shaft vibration propagated from the rotary member to the radial bearing portion 31 cannot be sufficiently damped by the O-ring.

In addition, in the above (01 example), the radial bearing member 41
Since the and thrust bearing member 42 are separated, even if the thrust bearing member 42 is fixed to the 7 frame (not shown) with bolts 46, the radial movement of the radial bearing member 41 is not restricted. However, since the radial bearing member 41 and the thrust bearing member 42 cannot be machined at the same time, the perpendicularity between the inner surface 411 of the radial bearing portion 41 and the end surface 422 of the thrust bearing portion 42 cannot be provided with high precision.

Furthermore, there is a drawback that a biased O-ring is required to seal the supplied gas, which increases the number of parts.

This invention was made in view of the above problems, and its purpose is to sufficiently damp the radial shaft vibration propagated from the rotating body to the radial bearing member when whirl occurs. It is an object of the present invention to provide a hydrostatic gas bearing which can provide a perpendicularity between the inner surface of a radial bearing member and a thrust bearing member with high precision.

[Means for solving problems]

The above purpose is to provide a rotating body having a flange with at least one end face perpendicular to the central axis, a radial bearing surface that fits on the outer peripheral surface of the rotating body, and one end face of the flange of the rotating body. The bearing member is fixed to a bearing member having opposed thrust bearing surfaces and in which a radial bearing portion and a thrust bearing portion are integrally molded, and an O-ring that is fitted into a circumferential groove formed on the outer periphery of the bearing member. a frame formed in the frame and connected to an external air supply source; a gas supply port formed in the bearing member that communicates with the gas supply port and supplies the supplied gas to the outer circumferential surface of the rotating body and the In a static pressure gas bearing that is provided with an air supply hole that discharges air toward one end surface of a lunge and that supports the rotating body in a non-contact manner, a mounting portion is provided in the thrust bearing portion of the bearing member to attach the bearing member. This is achieved by fixing to the frame and providing a plurality of ring-shaped grooves at positions avoiding the radial bearing surface or thrust bearing surface of the bearing member.

[Effect]

In a static pressure gas bearing configured as described above.

Since a ring-shaped groove is provided at a position avoiding the radial bearing surface or the thrust bearing surface of the bearing member in which the radial bearing part and the thrust bearing part are integrally molded, the mounting part of the bearing member to the 7-frame and the radial The bearing part is vibrationally separated, and the radial shaft vibration propagated from the rotating body to the radial bearing part of the bearing member can be sufficiently damped.

Furthermore, since the radial bearing part and the thrust bearing part of the bearing member have an integral structure and can be machined at the same time, the perpendicularity between the radial bearing surface and the thrust bearing surface can be given with high precision. Can be done.

〔Example〕

Below, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a first embodiment of a hydrostatic gas bearing according to the present invention.

In FIG. 1, the blade is a cylindrical bearing member, and its radial bearing portion 51 and thrust bearing portion 52 are integrated. Therefore, the radial bearing surface 511 of the radial bearing section 51 that fits on the outer peripheral surface of the rotating body and the thrust bearing surface 521 of the thrust bearing section 52 that faces one end surface 551 of the flange I of the rotating body are simultaneously machined. The radial bearing surface 511 and the thrust bearing surface 5 can be
21 can be finished with extremely high precision.

This bearing member blade has an air supply hole 5 that communicates with a gas supply port 59 formed in the frame and connected to an external air supply source.
1m and 52a are formed, and the supplied gas is discharged from the respective gas supply holes 51a and 52a toward the outer peripheral surface of the rotating body and the end surface 551 of the flange housing.

Further, an O-ring group is fitted into the outer periphery 1 (the formed circumferential groove 51b) of the radial bearing portion 51 of the bearing member blade. This O-ring group seals the gas supplied from an external air supply source. At the same time, the radial shaft vibration propagated through the radial bearing portion 51.1 is damped.

Further, between the bearing members, stepped mounting portions are formed that protrude from the thrust bearing portion 52 in the radial direction of the rotating body. By fixing with , the space between the bearing members is attached to the frame group.

Reference numeral 60 denotes a plurality of ring-shaped grooves formed on the inner side of the mounting portion, avoiding the radial bearing surface 511 and the thrust bearing surface 521 between the bearing members, and which are formed on the inner side of the mounting portion, avoiding the radial bearing surface 511 and the thrust bearing surface 521 between the bearing members. This is a device that vibrationally separates the marks.

In the static pressure gas bearing configured as described above, since the radial bearing portion 51 between the bearing members and the mounting portion are vibrationally separated, the rotational speed of the rotating body increases and whirl occurs. When this is about to occur, the radial bearing portion 51 propagates the vibration of the rotating body 51 and moves in the radial direction, and the vibration of the rotating body 51 is damped by the action of the O-ring &. In this way, the generation of whirl is suppressed, and the rotating body can be rotated at high speed.

FIG. 2 shows a second embodiment of a hydrostatic gas bearing according to the present invention. In order to simplify the explanation, the same parts as those in the first embodiment are given the same reference numerals and the explanation will be omitted.

As shown in the figure, in the second embodiment, a plurality of ring-shaped grooves 62 for vibrationally separating the radial bearing part 51 and the mounting part between the bearing members are connected to the radial bearing part 51 and the thrust part. They are formed at positions between the bearing parts 52 at appropriate intervals in the meticulous direction. A gas supply port 61 that communicates with the air supply hole 52a is formed toward the thrust bearing part from the outside of the mounting part between the bearing members so as to avoid this ring-shaped groove 62.

Note that in the second embodiment as well, as in the first embodiment, the occurrence of whirl is suppressed and it is possible to rotate the one-turn object at high speed.

〔Effect of the invention〕

According to the present invention, there is provided a rotary body having a flange whose one end face is perpendicular to the central axis, a radial bearing surface that fits on the outer peripheral surface of the rotary body, and a
A bearing member having a thrust bearing surface facing one end face of a flange and in which a radial bearing part and a thrust bearing part are integrally molded; and an O-ring fitted into a circumferential groove formed on the outer periphery of the bearing member. a frame to which the bearing member is fixed; a gas supply port formed in the frame and connected to an external air supply source; In a hydrostatic gas bearing that supports the rotating body in a non-contact manner and includes an air supply hole that discharges air toward the outer peripheral surface of the body and one end surface of the flange, a mounting portion is provided in the thrust bearing portion of the bearing member. The bearing member is fixed to the frame, and a plurality of ring-shaped grooves are provided at positions avoiding the radial bearing surface or thrust bearing surface of the bearing member, so that the following effects can be obtained. .

(1) By simultaneously machining the radial bearing surface and the thrust bearing surface of the bearing member, the perpendicularity between them can be finished with extremely high precision.

(The radial bearing part of the 21 bearing member is vibrationally separated from other constituent members, and the radial shaft vibration propagated from the rotating body to the radial bearing part is sufficiently damped, suppressing the occurrence of whirl. be able to.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a bearing member of a hydrostatic gas bearing showing a first embodiment of the present invention, and FIG. 2 is a sectional view of a bearing member of a hydrostatic gas bearing showing a second embodiment of the invention. Fig. 3 is a configuration diagram showing the structure of a general hydrostatic gas bearing according to the prior art, Fig. 4 is a characteristic diagram showing the relationship between the rotation speed of the rotating body and the radial axis displacement, and Fig. 5 is a diagram showing the whirl ratio. FIG. 6 is a sectional view of a hydrostatic gas bearing for explaining means for increasing the size; FIG. 6 is a sectional view of a bearing member of a conventional hydrostatic gas bearing in which a radial bearing portion and a thrust bearing portion are integrally molded; The figure is a sectional view of a bearing member of a conventional hydrostatic gas bearing in which a radial bearing member and a thrust bearing member are separated. 50: Bearing member, 51 Nirasial bearing portion, 511 Nirasial bearing portion, 51b: Circumferential groove, 51a, 52a: Air supply hole. 52 Nilast bearing part, 521 Nilast bearing surface, 53
: 0 ring, 54 = rotating body, 55: flange, 56: mounting part, 57: bolt, 58: frame, 59.6]: gas supply port, mark, 61: IJ song groove. Hair 3 S Tll mz? +3 100 ktiM whispering ward pa

Claims (1)

[Claims] 1) A rotating body having a flange with at least one end face perpendicular to the central axis, a radial bearing surface that fits on the outer peripheral surface of the rotating body, and a radial bearing surface that faces one end face of the flange of the rotating body. A bearing member having a thrust bearing surface and in which a radial bearing part and a thrust bearing part are integrally molded, an O-ring fitted into a circumferential groove formed on the outer periphery of the bearing member, and a frame to which the bearing member is fixed. a gas supply port formed in the frame and connected to an external air supply source; and a gas supply port formed in the bearing member and communicating with the gas supply port, and transmitting the supplied gas to one of the outer circumferential surface of the rotating body and the flange. In the hydrostatic gas bearing for supporting the rotating body in a non-contact manner, the bearing member is provided with a mounting portion in the thrust bearing portion of the bearing member, and the bearing member is attached to the frame. What is claimed is: 1. A static pressure gas bearing, characterized in that the bearing member is fixed and a plurality of ring-shaped grooves are provided at positions avoiding a radial bearing surface or a thrust bearing surface of the bearing member.