JPS649495B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to fluid thrust bearings.

Hydrodynamic bearings using gas such as air are widely used in various fields. This fluid bearing usually has two members that are movable relative to each other, and the two members are separated by a predetermined distance, and the gap between them is filled with a fluid such as air, so that the holding pressure of this fluid prevents the two members from coming into contact with each other. It can be effectively used especially as a fluid thrust bearing.

(Prior Art) In recent years, fluid bearings, particularly air bearings based on fluid dynamics, have been constructed to perform a supporting function by disposing a foil in a gap between two relatively movable bearing members. This type of foil is usually a thin sheet of flexible material that can be displaced by hydrodynamic forces generated between adjacent bearing surfaces, thereby improving the hydrodynamic properties of the hydrodynamic bearing. It is designed to be able to operate even under large loads that would cause damage to normal ball bearings. Furthermore, this type of foil is provided to have the advantage of being able to improve the buffering function by correcting any deviation that occurs between the two relatively movable members.

Relatively clean fluid or outside air can be easily used as the fluid for the bearing, and bearings lubricated with a hydrodynamic fluid film are particularly suitable for application to high-speed rotating machines. In this case, the load bearing capacity of a fluid bearing based on fluid dynamics is determined only by the pressure generated in the fluid film due to the relative movement of two adjacent bearing surfaces, and the load bearing capacity is increased by increasing the pressure of the fluid between the bearing surfaces from the outside. It often needs to be increased. This increase in fluid pressure requires a source of clean compressed fluid.

A variety of fluid thrust bearings have been proposed in which an elastic foil is suitably placed between two relatively movable members to obtain the above-mentioned advantages. For example, in the fluid thrust bearing disclosed in U.S. Pat. No. 3,635,534, a general-purpose structure is adopted in which a plurality of foils are fixedly spaced apart from each other on a disk by spot welding or the like, and the disk is disposed on one of the two members. There is. Also, U.S. Patent Nos. 3,893,733 and
No. 4,153,315 discloses a hydrodynamic thrust bearing constructed with a separate elastic reinforcing member disposed below the foil to provide the desired preload.

(Problem to be Solved by the Invention) In the hydrodynamic bearing of U.S. Pat. No. 3,635,534, in order to stabilize the foil in all operating conditions, it is necessary to reliably preload the foil, that is, a plurality of foils are installed. It is necessary to apply a preload to the supporting member that is paired with the supporting member and is movable relative to the other supporting member through the respective foils, and since the foils must have sufficient springiness, the bearing function cannot be improved. There was a fear that it would be damaged. Furthermore, the fluid bearings disclosed in US Pat. No. 3,893,733 and US Pat. No. 4,153,315 have a problem in that when a large load is applied, the bearing capacity of the elastic reinforcing member is exceeded, the bearing function is lost, and rotation becomes impossible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fluid thrust bearing that can impart elasticity to the oil without causing support to the bearing function, does not make rotation difficult, and can improve reliability.

(Means for Solving the Problems) According to the present invention, in particular, the foil thrust bearing is provided with a thrust bearing holder having alternating upper ridge portions and lower ridge portions, and the upper ridge portion of the thrust bearing holder is The above object can be achieved by making the height of the lower ridge larger than that of the lower ridge.

(Function) In the present invention configured as described above, the height of the upper ridge of the thrust bearing holder is made larger than the length of the lower ridge, so that the pressure of the fluid film comes into contact with the upper ridge during operation. An effect can be obtained that can effectively prevent the thrust bearing disk surface from coming into contact with the thrust plate surface that abuts the ridge portion.

(Example) Referring to FIG. 1, a fluid thrust bearing according to the present invention is shown, and the fluid thrust bearing is equipped with a thrust runner 10 including a shaft 12,
The thrust runner 10 is a thrust bearing disk 14
It is rotatably supported on a thrust plate 28 via a thrust bearing holding plate 22 preferably having spring properties. A plurality of fan-shaped bearing foils 16 are fixed to the thrust bearing disk 14, and the thrust bearing holder 22 has a plurality of upper and lower ridges 24 and 26 alternately formed upward and downward. It is provided to perform the function of fixing the thrust bearing disk 14.

As shown in detail in FIGS. 2 to 4, the thrust bearing holder 22 is equipped with an annular disk, and the annular disk is connected to the upper ridge portion 24 and the lower ridge portion through a portion having a thickness td of 0.0025 to 0.05 cm. The section 26 is continuous, thin and elastic, and can be made by well-known chemical etching techniques. The upper ridge part 24 of this thrust bearing holder 22 has a length of _t1 , and especially the second
As shown in the figure, the upper ridge part 2 is provided with a width that gradually expands outward in the radial direction.
The width of the outer circumferential side of 4 is W ₀ , and _the width of the inner circumferential side is W _{1 .}
Increased by about %. In this case, a radially extending line is drawn on the thrust bearing holder 22 by the ridge portion 24 that coincides with the radius line of the thrust bearing holder 22.

One or more of the upper ridges 24 are provided with an outer protrusion 25 having a notch 29, which allows the position of the thrust bearing holder 22 to be maintained constant with respect to the thrust plate 28. Similar protrusions 27 are provided on the circumferential portion of the thrust bearing disk 14 and are spaced apart from each other in the circumferential direction. In addition, the roof section 2
4 has an inner protrusion 23 extending radially inward from the inner peripheral edge of the thrust bearing holder 22 .

The lower ridge portion 26 has tabs 34 extending toward the thrust plate 28, and the tabs 34 are attached to each lower ridge portion 26 such that tabs 34 are located on the inner circumference side and tabs located on the outer circumference side alternately. is provided. In this case the tabs 34 are initially preloaded in the hydrodynamic thrust bearing and the thrust plates 28,
Thrust bearing holder 22, thrust disk 24
In addition, a contact force is applied to the thrust runners 10 to keep them stationary. On the other hand, the tab 34 is relatively flexible and is formed so that it can be easily deformed, for example, by hydrodynamic pressure when the lower ridge 26 is in contact with the thrust plate 28 (particularly as shown in FIG. 6). reference).

The lower ridge part 26 is made into a width of T ₂ and a width of W ₂ ,
Preferably, this lower ridge portion 26 also has a width W _a on the inner circumferential side and a width W _b on the outer circumferential side, and is gradually expanded outward in the radial direction. In this case, the radially outward expansion width of the lower ridge portion 26 is considerably larger than that of the upper ridge portion 24 (see especially FIG. 4). Further, the width of the continuous portion between the upper ridge portion 24 and the lower ridge portion 26 gradually narrows in the radial direction outward (see especially FIG. 4). Furthermore, the height t ₁ of the upper ridge part 24 is the lower ridge part 2
Although the values of t ₁ and _{t 2 can} vary depending on the operating conditions to which the fluid thrust bearing is subjected, typically t ₁ is 0.002 to 0.025 cm larger than t ₂ ; Provisions are made to facilitate deformation of the thrust disk when subjected to hydrodynamic pressure.

Further, the elasticity, that is, the modulus of elasticity of the thrust bearing holder 22 can be changed by changing the thickness or dimensions of the upper ridge portion 24 and the lower ridge portion 26. It is preferable that the space having a width W ₃ between the lower ridge portions 26 is slightly narrowed in the radial direction outward, so that the influence of the hydrodynamic pressure increasing in the radial direction is not excessively applied. This function contributes to smoothly placing the thrust bearing holder 22 in a fixed state. In addition, the grooves 30 and 32 are formed in the thrust bearing holder 2.
2, and is bored so as to cross the upper ridge part 24 in the circumferential direction, so that the upper ridge part 24
is divided into three parts. That is, the upper ridge 24 is gradually expanded outward in the radial direction and is divided into three parts, so that the influence of this pressure becomes excessive with respect to the hydrodynamic pressure that increases in the radial direction. This contributes to smoothly placing the thrust bearing holder 22 in the fixed state.

The foil thrust bearing of the present invention will be described in detail with reference to FIG. 5 showing a static state and FIG. 6 showing an operating state. In the figure, the thrust bearing holder 22
The dimensions are shown exaggerated compared to the thrust bearing disk 14, especially in the axial direction. In this case, the upper ridge part 24 and the lower ridge part 26 of the thrust bearing holder 22
The positional relationship of the thrust bearing disk 14 and bearing foil 16 relative to each other and, in particular, the interaction of the components in the operating state are shown clearly.

More specifically, in the stationary, non-operating state shown in FIG. 5, the ridge 24 of the thrust bearing holder 22 is located below the rear half (in the rotational direction) of the bearing foil 16 of the thrust bearing disk 14. Further, in this stationary state, neither the thrust bearing disk 14 nor the thrust bearing holder 22 is deformed, and both maintain positions substantially perpendicular to the direction of the rotational axis. Here, the arrow attached to the thrust runner 10 indicates that the thrust runner 10 is connected to the bearing foil 16 on the thrust bearing disk 14.
It shows the direction of rotation relative to the rotation direction. Also, the bearing foil 16 may be slightly curved so that a hydrodynamic fluid film can be smoothly formed between the bearing foil 16 and the thrust runner 10 (see FIG. 5).
Or, its front edge is thinner than other parts.

When the thrust runner 10 and the thrust plate 28 begin to rotate relative to each other, a hydrodynamic fluid film is formed between the bearing foil 16 and the thrust runner 10, resulting in an operating state as shown in FIG.
Changes in the pressure of the fluid film formed on each bearing foil 16 at this time are shown by changing the lengths of the long and short arrows above the bearing foil 16 on the left side of FIG. That is, this pressure is minimum at the front edge of the bearing foil 16, and gradually increases toward the region where the upper ridge 24 of the thrust bearing holder 22 is located below, and reaches the maximum pressure immediately above the upper ridge 24, It then decreases toward the trailing edge of the bearing oil 16 and reaches zero near the trailing edge. As the foil thrust bearing operates, the thrust bearing disc 14 and the bearing foil 1
6 is deformed as shown in FIG. 6, and at the same time, the thrust bearing holder 22 is also deformed by the pressure of the fluid film. In this case, the ridge part 2 of the thrust bearing holder 22
6, the upper position does not change, but the distance d ₁ between the upper part of the ridge part 26 of the thrust bearing holder 22 and the side surface of the thrust bearing holder 22 of the thrust bearing disk 14 becomes shorter than t ₁ by about 0.0025 cm to 0.0127 cm,
It will function properly as a thrust bearing.

Further, during operation, the thrust bearing holder 22 is displaced toward the thrust plate 28 by a distance d ₂ below the ridge 24, and the thrust bearing holder 22
The distance between the thrust plate 28 and the thrust plate 28 is smaller than the length t ₂ of the lower ridge portion 26. This interval t ₂ -d ₂ is maintained by the hardness of the thrust bearing holder 22 and the pressure of the fluid film due to hydrodynamics. If t ₁ is set at least 0.0127cm larger than t ₂ , then d ₂ becomes
_t2 , and in some cases, even when the thrust bearing holder 22 comes into contact with the same thrust plate 28, the thrust bearing disk 14 is supported by the upper ridge part 24. A fluid foil can be formed in the form shown in FIG. On the other hand, if t ₁ and t 2 and d _{2 and t 1 are} equal, the top of the upper ridge 24 will not be higher than the upper surface of the thrust bearing holder 22 and the bearing foil 16
It will be appreciated that a fluid film cannot be smoothly formed through the intervening process.

Although the fluid thrust bearing of the present invention has been described above with reference to the illustrated embodiment, the present invention can also be applied to a conical bearing that includes a thrust member, for example. Therefore, the present invention is not limited to the illustrated embodiment, but includes various design changes that fall within the scope of the claims.

(Effects of the Invention) According to the present invention configured as described above, by using the unique thrust bearing holder, the thrust bearing disk surface and the thrust plate surface do not come into contact with each other during operation, and a good fluid film can be formed. By interposing this, it is possible to obtain the same bearing function as possible, and the reliability of the bearing can be significantly improved with an inexpensive structure.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a fluid thrust bearing according to the present invention, Fig. 2 is an enlarged plan view of the same part, Fig. 3 is a side view taken from line 3-3 in Fig. 2, and Fig. 4 is an enlarged view of the same part. Bottom view, Figure 5 is an enlarged sectional view of the same stationary state,
FIG. 6 is an enlarged sectional view of the same operating state. 10... Thrust runner, 12... Shaft, 14...
... Thrust bearing disk, 16... Bearing oil, 22... Thrust bearing holder, 23... Inner protrusion, 24... Upper ridge, 25... Outer protrusion,
26...Subridge part, 27...Protrusion part, 28...Thrust plate, 29...Notch part, 30, 32...
Groove, 34...tab.

Claims (1)

[Scope of Claims] 1 A pair of members arranged to be relatively rotatable, one of which is rotatably supported by the other, and a pair of members arranged between a pair of relatively rotatable members. The foil bearing has a thrust bearing disk including an elastic foil and a plurality of upper ridge parts and lower ridge parts arranged alternately, and a plurality of upper ridge parts and lower ridge parts. 1. A fluid thrust bearing comprising: a thrust bearing holder whose width is larger than that of a ridge portion. 2. The fluid thrust bearing according to claim 1, wherein a plurality of elastic foils are individually arranged on a thrust bearing disk. 3. The fluid thrust bearing according to claim 1, wherein an elastic foil is integrally disposed on the thrust bearing disk. 4 The height of the upper ridge is 0.0025~ than that of the lower ridge.
The fluid thrust bearing according to claim 1, which has a size of 0.025 cm. 5 A thrust runner, a thrust plate that rotatably supports the thrust runner, and an elastic foil support installed between the thrust runner and the thrust plate, and the foil support has a thrust bearing disk and a thrust bearing holding member. A fan-shaped elastic foil is fixed to the thrust bearing disk, and the thrust bearing holder has a plurality of upper and lower ridges located alternately in the circumferential direction between the thrust bearing disk and the thrust plate. A fluid thrust bearing having a ridge, the upper ridge being 0.0025 to 0.025 cm larger than the lower ridge. 6. The fluid thrust bearing according to claim 5, wherein a plurality of fan-shaped elastic foils are individually fixed on a thrust bearing disk. 7. Claim 5, in which a sector-shaped elastic foil is integrated with a thrust bearing disk.
Fluid thrust bearings as described in section. 8. The fluid thrust bearing according to claim 5, wherein the space between the lower ridge parts is reduced in the radial direction. 9. The fluid thrust bearing according to claim 5, wherein the upper ridge portion is expanded radially outward. 10. The fluid thrust bearing according to claim 5, wherein the lower ridge portion is expanded radially outward. 11. The hydrodynamic thrust bearing according to claim 5, wherein the superstructure has at least one groove extending substantially parallel to the periphery of the thrust bearing holder, dividing the superstructure into at least two parts. . 12 The upper ridge divides the upper ridge into three parts2
12. A hydrodynamic thrust bearing as claimed in claim 11, comprising two grooves substantially parallel to the periphery of the thrust bearing holder. 13. The hydrodynamic thrust bearing according to claim 5, wherein the lower ridge portion has an outwardly extending tab. 14. The fluid thrust bearing according to claim 13, wherein the tab is located on the radially outer side of the ridge portion. 15. The fluid thrust bearing according to claim 13, wherein the tab is located inside the ridge portion in the radial direction. 16. The fluid thrust bearing according to claim 13, wherein the tabs are alternately arranged on the radially inner side and the radially outer side of each subridge portion. 17. The hydrodynamic thrust bearing according to claim 9, wherein the side surface of the upper ridge part expanding radially outward substantially coincides with a line extending in the radial direction of the thrust bearing holder. 18 Claim 5, wherein the upper ridge extends inwardly beyond the inner peripheral edge of the thrust bearing disk.
Fluid thrust bearings as described in section. 19 In a thrust bearing holder for a fluid thrust bearing comprising an annular disk having elasticity, a plurality of upper ridges fixed on the surface of the disk, and a plurality of lower ridges fixed on the back surface of the disk, A thrust bearing holder characterized in that it is provided 0.0025 to 0.025 cm larger than the ridge part. 20. The thrust bearing holder according to claim 19, wherein the space between the lower ridge parts is reduced in the radial direction. 21. The thrust bearing holder according to claim 19, wherein the upper ridge portion is expanded radially outward. 22. The thrust bearing holder according to claim 19, wherein the upper ridge portion is expanded radially outward. 23. The thrust bearing according to claim 19, wherein the upper ridge has at least one groove extending substantially parallel to the periphery of the thrust bearing holder, dividing the upper ridge into at least two parts. holding body. 24 The upper ridge divides the upper ridge into three parts2
20. A thrust bearing holder according to claim 19, comprising two grooves substantially parallel to the circumferential edge of the thrust bearing holder. 25. The thrust bearing holder according to claim 19, wherein the lower ridge portion has an outwardly extending tab. 26. The thrust bearing holder according to claim 25, wherein the tab is located on the radially outer side of the ridge portion. 27. The thrust bearing holder according to claim 25, wherein the tab is located inside the ridge portion in the radial direction. 28. The thrust bearing holder according to claim 25, wherein the tabs are alternately arranged on the radially inner side and the radially outer side of each subridge portion. 29. The thrust bearing holder according to claim 21, wherein the side surface of the upper ridge part expanding radially outward substantially coincides with a line extending in the radial direction of the thrust bearing holder. 30. The thrust bearing holder according to claim 19, wherein the upper ridge extends inward beyond the inner peripheral edge of the disk.