JPH02142919A - Squeeze bearing - Google Patents

Abstract

PURPOSE:To obtain an economical squeeze bearing with the unsevere assembly accuracy and the reduced number of the parts by forming a spherical recessed part or projecting part on one end surface, at least, of a rotor, and forming the vibrating surface of a vibrator facing to the rotor with the projecting part or the recessed part. CONSTITUTION:Hemispherical recessed parts 1a, 1b having the small surface roughness are provided in both end surfaces of a rotor 1 so that the centers of the spheres are positioned on the axial line. On the other had, hollow hemispherical vibrators 2, 3 smaller than the recessed parts 1a, 1b and made of the piezoelectric material and having the small surface roughness are respectively attached to tie rods 4, 5, keeping the minute clearance from the surfaces of the recessed parts 1a, 1b. The inner surface of the vibrator 2 is distributed to four electrodes 2a, 2b, 2c, 2d, and the outer surface forms an even electrode 2 which doubles as the bearing surface, and the mutually opposite phase voltage are applied to the pair of the electrodes 2a and 2b, and the pair of the electrodes 2c and 2d so that the vibration is generated. When the vibrators 2, 3 are vibrated, the air films 6, 7 having the higher pressure than the circumference and the rotor 1 can be non-contactly supported in both radial and thrust directions.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention uses a vibrator that vibrates at a high frequency to support a rotor in a non-contact manner by a positive pressure air film generated in a minute gap between the rotor and the vibrator. related to squeeze bearings.

[Conventional technology] FIG. 10 is a diagram explaining the principle of a squeeze bearing.

When the movable element 21 and the vibrator 22 are arranged with their surfaces with small surface roughness facing each other and the vibrator 22 is vibrated at a high frequency, an air film 23 is formed due to the viscosity and compressibility of air and the inertia of the movable element 21. , the movable element 21 is supported by the vibrator 22 in a non-contact manner.

FIG. 11 is a schematic diagram of a conventional squeeze bearing.

The rotor 24 is disposed within a hollow cylindrical radial support vibrator 25, and thrust support vibrators 26, 27 are disposed on both end faces of the rotor 24 with a certain gap between them. By making 27 vibrate at high frequency,
An air film 28, 29.30 having a pressure higher than that of the surroundings is formed between the rotor 24 and the vibrator 25, 26.27, and the rotor 24 is supported by the vibrator 25, 26.27 in a non-contact manner.

[Problems to be Solved by the Invention] In the conventional squeeze bearing described above, in order to support the rotor in a non-contact manner, the gap between the rotor and the vibrator must be on the order of microns. The mutually opposing surfaces of the vibrators must be finished with minimal surface roughness, and the mutual assembly precision must also be manipulated to ensure accuracy, which has the disadvantage of being expensive.

[Means for Solving the Problems] The squeeze bearing of the present invention is columnar, and has a concave or convex portion in the shape of a part of a sphere with small surface roughness on at least one end surface, so that the center of the core sphere is the axis. A rotor positioned on a line, and a flat or curved surface with small surface roughness provided opposite each end face of the rotor, and if the end face of the rotor is flat, a flat recess is provided. If a convex part is provided, the convex part is in the shape of a part of a sphere smaller than the sphere of the concave part. [Operation] A spherical concave or convex portion is formed on at least one end surface of the rotor, and a vibrator facing this By making the vibration surface also a convex portion or a concave portion, assembly accuracy does not need to be strict and the number of parts is reduced, resulting in lower cost.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of the first embodiment of the squeeze bearing of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is an inner view of the vibrator 2, and FIG. 4 is a diagram showing the vibration mode of the vibrator 2. FIG.

Hemispherical recesses 1 with small surface roughness are provided on both end faces of the rotor 10.
a and lb are provided so that the center of the sphere is located on the axis. On the other hand, it has the shape of a hollow hemisphere smaller than the recesses 1a and lb, and has a small surface roughness (the vibrators 2 and 3 made of piezoelectric material
are attached to the fixed rods 4.5 with a small gap between them and the surfaces of the recesses la and lb of the rotor 1, respectively. As shown in FIG. 3, the vibrator 2 has four electrodes 2a, 2 on its inner surface.
It is divided into electrodes b, 2c, and 2d, and the outer surface is a uniform electrode 2e that also serves as a bearing surface.
Voltages with opposite phases are applied to the pair b and 2d, and the fourth
It vibrates in the mode shown by the broken line in the figure (this is more efficient than expanding and contracting uniformly).

The same applies to the vibrator 3.

When the vibrator 2.3 is vibrated, an air film 6.7 having a higher pressure than the surrounding air is formed as described above, and the rotor 1 can be supported in both radial and thrust directions without contact.

In this way, since the rotor 1 and the vibrator 2.3 are spherical and face each other, even if there is an error in the relative angle or direction perpendicular to the central axis of the rotor 1 in their arrangement, it can be absorbed. can. Therefore, it is only necessary to accurately set the distance between the vibrators 2 and 3 in relation to the dimensions of the rotor 1.

Note that in this embodiment, the number of parts is reduced.

FIG. 5 is a side view of a second embodiment of the squeeze bearing of the present invention.

In this embodiment, the vibrator 2 is supported by a leaf spring 8.

By doing so, the accuracy of setting the position of the vibrator 2 is further reduced compared to the first embodiment, and the bearing can be constructed economically.

FIG. 6 is a side view of a third embodiment of the squeeze bearing of the present invention.

In this embodiment, the vibrator 2 is supported by a coil spring 9. Note that both vibrators 2 and 3 can also be supported by springs.

FIG. 7 is a perspective view of a fourth embodiment of the squeeze bearing of the present invention, and FIG. 8 is a longitudinal side view thereof.

In this embodiment, the lower end surface of the rotor 9 is flat, and a vibrator lO having a shape similar to that of the conventional one is used.

FIG. 9 is a longitudinal side view of a fifth embodiment of the squeeze bearing of the present invention.

In this embodiment, hemispherical convex portions are formed on both end faces of the rotor 12! 2a and 12b are provided, and a vibrator 13 facing thereto.
．． The vibration surface 14 is a hemispherical recess. In this case, the divided electrodes of oscillator 13.14 are
It is formed on the outside of 4.

[Effects of the Invention] As explained above, the present invention is characterized in that a spherical recess or convex portion is formed on at least one end face of the rotor, and the vibrating surface of the vibrator facing the spherical concave portion is also formed as a convex portion or a concave portion. Therefore, assembly accuracy does not have to be strict, and the number of parts is reduced, which has the effect of lowering the cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the first embodiment of the squeeze bearing of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is an inner view of the vibrator 2, and FIG. 4 is a diagram showing the vibration mode of the vibrator 2. The diagrams shown in FIGS. 5 and 6 respectively show the second embodiment of the squeeze bearing of the present invention. A side view of the third embodiment, FIG. 7, and FIG. 8 are respectively a perspective view and a vertical cross-sectional view of the fourth embodiment of the squeeze bearing of the present invention.
The figure is a longitudinal side view of the fifth embodiment of the squeeze bearing of the present invention, FIG. 10 is a diagram explaining the principle of the squeeze bearing, and FIG.
FIG. 1 is a longitudinal sectional view of a conventional example of a squeeze bearing. 1.9.12... Rotor, la, lb... Concave portion, 12a, 12b... Convex portion, 2.3.10.13.14... Vibrator, 28-2e.
...electrode, 4.5...fixing rod, 6.7.1 air film, 8...plate spring, 9...coil spring. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Scope of Claims] 1. A rotating device that is columnar and has a concave or convex portion in the shape of a part of a sphere with low surface roughness on at least one end surface so that the center of the sphere is located on the axis. A flat or curved surface with small surface roughness, which is provided facing each end face of the rotor, and is flat when the end face of the rotor is flat, and is flat when a recess is provided. The vibration surface of the convex part in the shape of a part of a sphere smaller than the sphere in the concave part, or, if a convex part is provided, in the shape of a part of a sphere larger than the sphere in the convex part, of the rotor. A squeeze bearing that includes an end face and a vibrator with a certain gap.