JPH0339618Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a squeeze film bearing structure that supports a rotating shaft by using fluid film pressure.

[Prior Art] A squeeze film bearing is a type of bearing that forms a high-pressure fluid film between a fixed surface and a bearing that directly supports a rotating shaft, and supports a rotating body using this fluid film pressure. It has the feature of reducing vibration, and is extremely effective as a bearing for high-speed rotating shafts such as turbo compressors, turbo expanders, turbo chargers, and turbo refrigerators.

As shown in FIG. 5, in the conventional squeeze film bearing structure of this type, the rotating shaft 1 is connected to the rolling bearing 2.
An annular outer ring retainer 4 is integrally attached to the outer ring 3. The outer ring retainer 4 is arranged along the axial direction and is supported by the support surface 6a of the bearing case 6 via a plurality of spring pins 5 provided at appropriate intervals along the circumferential direction. The bearing surface 6a is supplied with oil through an oil supply hole 8. The center part of the spring pin 5 bends outward to exhibit a spring function, and is pushed by the spring pin 5 and moves up and down slightly, generating fluid pressure on the bearing surface 6a due to the squeezing effect. ing.

Another conventional technique, as shown in FIG. 6, is to supply oil directly to the outer circumferential surface of the outer ring holder 4 through an oil supply hole 8 formed in the bearing surface 6a to create a squeezing action in this area. A plurality of leaf springs 9 are extended from the outer ring holder 4 along the length of the shaft, and the end portions of the leaf springs 9 are attached to the fixed body 10, thereby causing the leaf springs 9 to exert a spring action.

[Problem to be solved by the invention] However, in the prior art described above, since the spring element and the squeeze element are each housed in separate members, in the prior art shown in FIG. The conventional technique shown in FIG. 6 requires a large space in the axial direction. For this reason, the conventional squeeze film bearing structure has a problem in that it cannot be applied to areas with limited space.

Also, even if improvements can save space,
If the structure is more complicated than the conventional one, it is impractical. That is, it is desirable that the structure be simple and easy to manufacture, and that the desired vibration damping characteristics can be easily obtained.

In view of the above circumstances, the present invention was devised to provide a squeeze film bearing structure that saves space and can easily obtain desired vibration damping characteristics.

[Means for Solving the Problems] The present invention involves inserting a cylindrical thin plate between the outer ring of a bearing attached to a rotating shaft and the bearing surface of a bearing case that covers this outer ring. Concave portions formed by etching are arranged on the outer surface at equal intervals and alternately in the circumferential direction, and fluid passages for supplying and discharging fluid to generate a predetermined fluid film pressure are connected to the concave portions.

[Function] With the above configuration, the recesses to which the fluid is supplied exhibit a vibration damping function due to the fluid film pressure, and since they are arranged alternately, they exhibit a spring function in the thickness direction of the member.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of the squeeze film bearing structure according to the present invention, and structures similar to those of the conventional structure are denoted by the same reference numerals, and their explanations will be omitted.

This squeeze film bearing structure
The outer ring 3 of the rolling bearing 2, which is a bearing attached to the bearing, and the bearing surface 16 of the bearing case 11 that covers the outer ring 3.
A cylindrical thin plate 17 is inserted between the thin plate 17 and
Recesses 20 and 19 formed by etching are arranged on the inner and outer surfaces of the recesses 20 and 19 at regular intervals and alternately in the circumferential direction. An oil supply hole 23 and an oil drain hole 24, which are fluid passages for supplying and discharging fluid, are connected to each other.

The outer ring 3 has an annular outer ring support ring 1 around its outer periphery.
2, and an outer ring holder 13 is fitted on one side of the bearing to prevent the rolling bearing 2 from coming off, forming an outer ring side 14. The outer circumference of the outer ring support ring 12 is housed in a groove 15 formed on the inner circumference side of the bearing case 11, so that it can move slightly in the radial direction of the shaft.

As shown in FIGS. 3 and 4, the recess 20,
19 has a rectangular shape and extends over the entire width of the thin plate 17, that is, in the axial direction. This recess 2
0 and 19 are formed by drawing a predetermined pattern on both sides of a thin strip metal plate and removing the portions corresponding to the recesses using a chemical method or the like (photoetching). This band-shaped metal plate is then curved to form a cylindrical thin plate 17.

Further, convex portions 22 and 21 substantially defined by these concave portions 20 and 19 are adapted to abut on the outer circumferential surface of the outer ring support ring 12 and the bearing surface 16, respectively. And these convex parts 22, 21
are arranged so as to correspond to substantially the circumferential center of the recesses 19 and 20 on opposite sides, respectively. Therefore,
For example, if a load is applied to the convex portion 22 on the inner surface, the thin plate 17 at that portion will bend radially outward, exerting an elastic force to counter the load. The spring constant at this time is the member thickness of the thin plate 17, the recess 1
Widths of 9 and 20, convex portions 21 and 22 and concave portions 19 and 20
A desired value can be set by appropriately selecting the width ratio and the like.

As shown in FIG. 2, the oil supply hole 23 is formed in the bearing case 11, and the oil drain hole 24 is formed in the damper retainer 18 for preventing the thin plate 17 from falling off, penetrating in the axial direction. There is.

Next, the operation of this embodiment will be explained.

When the rotating shaft 1 rotates, the rolling bearing 2 appropriately supports it. The vibration is caused by the outer ring support ring 1
2 to the thin plate 17. The recesses 19 and 20 of the thin plate 17 are filled with lubricating oil supplied from the oil supply hole 23, and by appropriate arrangement with the projections 21 and 22, a radial spring action is exerted, and at the same time, the lubricating oil is supplied from the oil supply hole 23. The thickness of the oil film layer within the recesses 19 and 20 changes with the bending deformation. This change in the oil film layer thickness generates pressure (fluid film pressure) in the oil film, exerting a vibration damping (squeezing) effect. Since this squeezing effect is exerted on both sides of the thin plate 17, it becomes very large.

In this way, the outer ring 12 of the bearing 2 and the bearing case 1
A thin plate 17 is inserted between the
9 and 20 are arranged at equal intervals and alternately, and the oil supply hole 23 and oil drain hole 24 are connected to these, so that
A single member can exhibit spring action and squeezing action, and the space required for the bearing structure can be significantly reduced.

Then, the recesses 19 and 20 are etched.
As a result, it can be manufactured precisely and extremely easily, and the depth, number, width, etc. of the recesses 19 and 20 can be freely selected to form a predetermined oil film, making it easy to obtain the desired vibration damping characteristics. be able to.

Although lubricating oil was used as the fluid in the above embodiments, the fluid is not limited to this, and gas (gas lubrication) may also be used.

Alternatively, a plurality of thin plates may be inserted and recesses formed in each of them to further increase the damping effect.

[Effects of the Invention] In summary, the present invention provides the following excellent effects.

A thin plate is inserted between the outer ring of the bearing and the bearing case that covers it, and recesses formed by etching on the inner and outer surfaces are arranged circumferentially at equal intervals and alternately, and a predetermined fluid film pressure is applied to the thin plate. Since the fluid passages for supplying and discharging the fluid for generation are connected, a single member can exert both spring action and vibration damping action, resulting in significant space savings, precision and extremely simple construction. The depth of the recess can be freely selected, and the desired vibration damping characteristics can be easily obtained.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing an embodiment of the squeeze film bearing structure according to the present invention, Fig. 2 is a side sectional view thereof, Fig. 3 is an exploded view of its main parts, and Fig. 4 shows its thin plate. FIG. 5 is a side sectional view showing a conventional squeeze film bearing structure, and FIG. 6 is a side sectional view showing another conventional squeeze film bearing structure. In the figure, 1 is a rotating shaft, 2 is a rolling bearing, 3 is an outer ring, 11 is a bearing case, 16 is a bearing surface, 17 is a thin plate, 19 and 20 are recesses, 23 and 2
Reference numeral 4 indicates an oil supply hole and an oil drain hole, which are fluid passages.

Claims (1)

[Scope of utility model registration request] A cylindrical thin plate is inserted between the outer ring of the bearing attached to the rotating shaft and the bearing surface of the bearing case that covers the outer ring, and recesses formed by etching are formed on the inner and outer surfaces of the thin plate in the circumferential direction. A squeeze film bearing structure characterized in that fluid passages are arranged at equal intervals and alternately and connected to the recesses for supplying and discharging fluid to generate a predetermined fluid film pressure.