JPS6174910A - Hydraulic bearing structure - Google Patents

Abstract

PURPOSE:To design decrease of the number of parts by laminating a spring foil having supporting projections integratedly on the whole bottom surface of an elastic foil body at equal intervals and an identical-shaped dump foil successively so that the supporting projections thereof are directed outward from the circumference. CONSTITUTION:Three elastic foils with flexibility of a spring foil 12, a dumping foil 13 and a bearing foil 14 are laminated in order on the support surface 11 of a bearing case 10 while on end of the foils is fixedly engaged by a key 15. The spring foil 12 and the dump foil 13 are in the same shape, and its elastic foil 18 has a flat surface on one side and plural line-shaped supporting projections 19 integratedly on the other side. The supporting projections 19 cross the whole part of the foil 18 by stretching at full width of the foil 18 along the longitude of the foil 18 at equal intervals.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a fluid bearing structure for gas, oil, water, steam, etc.
In particular, the present invention relates to improvements in hydrodynamic bearing structures that can easily exhibit submerged high-speed stability in foil bearings that utilize elastic foils.

[Prior Art] As a conventional technology of a hydrodynamic foil bearing groove using elastic foil, there is a patent application proposed by the inventor in 1986-24.
There is one shown in the specification of No. 2082. This is the 11th
As shown in the figure, four elastic foils, bearing foil 1, damping foil 2, spring foil 3, and rudder foil 4, are welded and laminated to the key 5, and appropriate external spring damping is achieved by these foil configurations. Its features include a spring tamping function with a bearing fluid film, plus extremely high speed stability. In addition, in the figure, 6 is an orifice, and 7 is a pocket.

[Problems to be Solved by the Invention] However, the above-mentioned conventional method has the disadvantage that the number of parts is large because four different types of elastic foils 1, 2, 3, and 4 are used. There was a problem in the durability of the rudder foil 4, which requires equally spaced dents in order to insert the rudder foil 3.

[Objective of the invention 1 The object of the present invention is to reduce the number of parts while maintaining excellent high-speed stability, improve the durability of the parts, and improve moldability and strength. The purpose of the present invention is to provide a hydrodynamic bearing groove that can be used.

SUMMARY OF THE INVENTION The structure of the present invention in accordance with the above-mentioned object is such that the main body of the spring foil has supporting protrusions integrally formed on the lower surface of the elastic foil main body at equal intervals, and the main body of the spring foil is suspended on the supporting surface of the bearing by the supporting protrusions. The dump foil is formed to have approximately the same shape as the spring foil, and the dump foil is formed in substantially the same shape as the spring foil so that the support protrusions are located between the support protrusions of the spring foil. The dump foil is elastically supported by the laminated rust on the spring foil and the elastic wave-like deformation of the spring foil body, while the increased fluid film pressure generated in the bearing gap is released to a greater extent on the outlet side than on the inlet side. ! The bearing foil that controls the release path is brought into close contact with the dump foil so that its release path faces the upper surface of the main body between the support protrusions of the dump foil, and the dump foil body is rotated by local deformation of the dump foil body due to the increased fluid film pressure from the release path. It is designed to dampen the vibration of the shaft. As a result, when automatic vibration of the bearing occurs at high speed, the self-excited vibration is absorbed by the spring action of the spring foil and the dump foil having approximately the same shape, and the squeeze film damper action is caused by local deformation of the dump foil. It is designed to cause ilJ vibration.

[Example] An example of the present invention will be described below based on FIGS. 1 to 6.

As shown in FIG. 1, the fluid journal bearing structure according to the present embodiment includes spring foils 12, 12, 12, 12, 12, 12, 12, 12, 22, 32, 32, 32, 30, 40, 40 spring foils, etc. Three flexible thin plates (elastic foils), a dump foil 13 and a bearing foil 14, are laminated and one end is locked and fixed with a key 15, and the bearing foil 14 of the inner shell and the rotating shaft 16 are Rotation@16 due to the separate functions of the spring damping function of the fluid film pressure formed in the bearing gap 17 between the bearings and the spring damping function of the laminated foil structure.
It is designed to support

Each elastic foil is a separate film-shaped structure as shown in FIGS. 2 to 5, and is inserted into the bearing case 10 to cover the bearing surface 11 in a ring shape. FIG. 2 shows the basic structure of the spring foil 12 or the dump foil 13, and in this embodiment, both have exactly the same shape. That is, the elastic foil main body 18 has a flat surface on one side, and a plurality of linear support protrusions 19 integrally arranged at equal intervals along the longitudinal direction of the foil, extending across the entire width of the foil on the other side. It's stone. This support protrusion 19 is formed by known photo etching.

It can be processed and formed using technology.

In the case of the spring foil 12, the support protrusion 19 supports the main body 18 by floating it on the bearing surface 11, and in the case of the dump foil 13, the support protrusion 19 supports the main body 18 on the support surface 11.
The dump foil main body 18 is similarly supported on top of the dump foil main body 18). The difference between the spring foil 12 and the dump foil 13 is that when they are inserted into the bearing case 10 and assembled,
The point where the pitch of one support protrusion is shifted by half, that is, the support protrusion 1919 of the spring foil 12
The point is that the dump foils 13 are stacked in a staggered manner so that the support projections 19 of the dump foils 13 are located between them.

However, as shown in FIGS. 3 and 4, in the spring foil 12, it is also possible to deform the support protrusion to prevent uneven contact of the bearing. In the 30th one, the width of the linear support protrusions 20 and 21 is the same, but the length is shortened by shaving off both ends of every other one, and the support protrusions 22 in FIG. Although the width is the same, the width is gradually narrower toward both ends compared to the center, and has the function of changing the spring constant in the width direction of the bearing.In other words, the width at both ends of the bearing is smaller than at the center This makes it possible to reduce the foil rigidity in the thickness direction (in the direction of clearance).

Fig. 5 shows the basic fS3fi of the bearing foil 14 which becomes a plain bearing, and the pressure release passages 23 necessary for high-speed stabilization are bored at equal intervals along the longitudinal direction of the foil.
have. The pitch between the pressure release passages 23 and 23 is the same as the pitch between the support protrusions 19 and 19 of the spring foil 12 or the dump foil 13, or an integral multiple thereof,
In the embodiment shown in FIG. 1, the number is doubled. Pressure release path 23
consists of two holes with different diameters in the plate thickness direction, the smaller diameter hole functions as an orifice 24, and the larger diameter hole functions as a pocket 25 for storing pressure. This bearing foil 14 has a pressure release path 23 on the upper surface of the main body 18 between the support projections 19 and 19 of the dump foil 13.
The dump foil 13 is closely stacked on the dump foil 13 so that the hooket 25 faces the dump foil 13.

Note that the bearing surface shape of the bearing foil 14 is flat for plain bearings, but herringbone,
It can also be made into a step type, pocket type, etc. shape and applied to general dynamic pressure type bearings.

Now, in the above-described configuration, when the rotating shaft 16 starts to rotate at high speed, the fluid film pressure generated in the bearing gap 17 becomes higher (as shown in FIG. 6), and this fluid film pressure P causes the bearing foil 14 to The spring foil 12 and the dump foil 13 are stacked and supported on the bearing surface 11 so that elastic deformation is allowed by one linear support protrusion. The spring foil 12 deforms into a wave shape. Also, due to the self-excited vibration of the rotating shaft 1G due to high-speed rotation, the bearing clearance 1
A part of the increased fluid film pressure generated at 7 passes through a release passage 23 formed in the bearing foil 14 and acts on the upper surface of the flat dump foil body 18. This action on the upper surface of the main body 18 is sufficient because the flow area of the release passage 23 is small on the inlet side and large on the outlet side, without reducing the high pressure fluid film pressure formed in the bearing gap 17. The dump foil body 18 can be large, so that the flexible dump foil body 18 is locally displaced radially outwards and the displaced portion is locally filled with fluid.

By the way, in order to operate a hydrodynamic bearing stably up to high speeds, in addition to the spring damping element of the bearing fluid film, it is necessary that an appropriate external spring damping element be placed at a distance of γa from the bearing surface. be.

However, in this embodiment, an appropriate external spring
The damping function is made up of three laminated foils. That is, as a spring element, the spring foil main body 18 is bent and deformed in the circumferential direction of the bearing due to the action of the fluid pressure P generated in the bearing gap 17, so that the springs are distributed and arranged in the circumferential direction. Become.

In addition, the dump foil body 1
8 is locally displaced and the fluid is locally filled along the circumferential direction, so this filled portion functions as a squeeze film damper, and this Ha is distributed and arranged in the circumferential direction. Therefore, according to the foil bearing according to this embodiment, it is possible to effectively suppress the self-help vibration of the journal bearing that occurs at high speed, and it is possible to achieve high speed stabilization. Along with this, it can withstand centrifugal expansion, centrifugal deformation, and thermal deformation, and improves centering clarity, so it is suitable for all high-speed turbo machines (turbo compression, turbo expansion, etc.) that use gas or liquid as the process fluid. It can be applied to machines, turbochargers, centrifugal refrigerators, etc.), and is particularly advantageous when applied to other types of high temperature or low humidity. Further, by providing the release path 23 in the bearing foil 14, there is a secondary effect that foreign matter can be discharged from the bearing gap 17.

However, in this embodiment, it is almost the same as the conventional method as described above.
1 Non-J) While maintaining high-speed stability steeped in 1゛, one elastic foil can be omitted compared to the conventional method, reducing the number of parts, reducing costs and achieving high (M) reliability. In addition, since it does not use a foil shaped like a rudder foil, durability can be improved, and there is no need for troublesome work such as inserting a spring foil into a rudder foil during assembly.
Assembling is extremely easy since it is sufficient to simply stack the foils. Furthermore, the support protrusions 19 provided on the spring foil 12 and the damper foil 13 can be easily processed using a known photo-etching technique, etc. ,
Since these foils can have the same shape,
The structure can be simplified.

FIG. 7 shows a modification of the embodiment shown in FIG. 1, and the difference from FIG. The end of the spring foil is locked and fixed to the key 15 by wrapping it three times on the bearing surface 11 of the spring foil. As shown in FIG. 8, the two integrally processed elastic foils are successive in the order of bearing foil portion B1 dump foil portion D and spring foil portion S from the left.

If the distance between the supporting protrusions 19 and 19 at the boundary between the dump foil part and the spring foil part S is set to 1.5 times the length of the bit b of the supporting protrusions 19 in each part, the bearing can be wrapped in three claws. When assembled in the case 10, one support protrusion of the dump foil part is positioned between the support protrusions 19 and 19 of the spring foil part S, thereby distributing the springs in the circumferential direction as shown in FIG. can be placed. Therefore, there is an advantage that the bearing can be configured with a single sheet of foil, making molding, assembly, and processing of the foil bearing easier.

Fig. 9 shows a modified example of the continuous foil shown in Fig. 8, in which the rigidity of the spring foil part S in the bearing width direction is changed by changing the length of the support protrusion of the spring foil part S to β0.21. It's different.

Next, FIG. 10 shows an embodiment in which the present invention is applied to a thrust bearing. The journal bearing and purchasing principle are the same, spring foil 30. It consists of three disc-shaped elastic foils: a dump foil 31 and a bearing foil 32 of the same shape.
A plurality of support protrusions 33 are arranged radially. The bearing foil 32 is illustrated as having a spiral group 34 engraved on its upper surface, and the group end of the spiral group 34 has a pressure release path consisting of an orifice and a pocket that serve to suppress automatic vibration at high speed. 35 is the perforation. Also in this case, as in the case of journal bearings, the foil tlil'? It is possible to deform the support projections 33 of the dump foil 31 and the spring foil 30 to change the direction of the foil 51 in the radial direction.

Spiral group type thrust bearings are of a type in which the thrust shaft rotates in the direction of the arrow to draw in the fluid along the group 34 and increase the pressure. Although it is a bearing with a very high load and high force, it can cause unstable vibration in the high speed range. occurs. but,
In this embodiment, the release path 35 is provided in the highest pressure generating part of the group end part so that the interfacial fluid film pressure acts on the upper surface of the dump foil 31. Therefore, the squeeze film damper is locally distributed to prevent the above-mentioned problem. High-speed stabilization can be achieved by suppressing stable vibration υ1.

In this way, this embodiment is able to achieve high-speed stabilization, but this is only possible because the members that make up the bearing are made of elastic foil, and this effect is not possible with ordinary rigid surface bearings. It is not practical.

[Effects of the Invention 1] According to the present invention, the following excellent effects are achieved.

(1) Compared to the conventional type that requires four layers of elastic foil, one layer can be omitted to simplify the bearing groove without compromising high-speed stability performance, reducing costs. .

(2) Instead of the conventionally required ladder foil, an elastic foil of approximately the same shape that integrally has support protrusions that are easy to mold and process is used, making it extremely easy to mold and process, and greatly improving durability. The three layers of elastic foil used are simply fI! Il! ! Assembly is easy as all that is required is I.

(3) Since the bearing foil has a release path that releases the increased fluid film pressure to a greater extent on the outlet side than on the inlet side, it is possible to impart a large 11 vibration effect to the dump foil, significantly increasing the automatic vibration suppression effect. I can do something.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing a preferred embodiment of the present invention, Fig. 2 is an exploded perspective view of the spring foil or dump foil in Fig. 1, and Figs. 3 and 4 show modified embodiments of the spring foil. 5 is a developed perspective view of the bearing foil shown in FIG. 1, FIG. 6 is a developed cross-sectional view in the circumferential direction of FIG. 1, and FIG. 7 is a front cross-section showing a modification of FIG. 1. Fig. 8 is a developed view of the elastic foil J3 in Fig. 7, Fig. 9 is a developed view showing a modified embodiment of Fig. 8, and Fig. 10 is an exploded front view of the thrust bearing structure having a pocket type group. 11 are assembly diagrams of a conventional fluid foil bearing structure. In the figure, 11 is a bearing surface, 12 is a spring foil, 13
is the dump foil, 14 is the bearing foil, 17 is the bearing gap, 18 is the main body of the spring foil or dump foil, 1 is the support protrusion of the spring foil or dump foil, 20.21.22 is the support protrusion, 23 is the release path. be. Patent Applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Representative Patent Attorney: Nobuo Kinuya Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Δ

Claims (1)

[Claims] A spring foil in which the main body is suspended and supported on a support surface by support protrusions provided integrally and at regular intervals on the lower surface of the elastic foil main body, and elastic deformation of the main body between the support protrusions is allowed; The dump foil is formed into approximately the same shape and is stacked on top of the spring foil so that the support protrusions are located between the support protrusions of the spring foil, and is elastically supported by the elastic deformation of the spring foil body. It has a release path that releases the increased fluid film pressure to a greater degree on the outlet side than on the inlet side, and this release path is closely placed on the dump foil so that it faces the top surface of the main body between the support protrusions of the dump foil, and the increased pressure from the release path is A fluid bearing structure comprising a bearing foil whose vibration is damped by local deformation of a dump foil body due to fluid film pressure.