JP2008111447A - Squeeze air bearing and plane actuator using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a squeeze air bearing which small in size is light in weight, simple, permissible to provide low processing and assembly precision, stable in gap variation, inexpensive, and excellent in squeeze air film pressure characteristics, and a plane actuator which eliminates the needs for massive ancillary facilities, which is a small sized and convenient device, and which enables high precise driving and positioning. <P>SOLUTION: In the squeeze air bearing, either a vibration plane 21 vibrated by a vibrator 1 or a plane opposite to the vibration plane is made not flat by providing a projection 22 in the outer periphery, so as to improve the squeeze air film characteristics. The plane actuator comprises the squeeze air bearing having the excellent squeeze air film force characteristics as a non-contact bearing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-contact air bearing, in particular, a squeeze air bearing and a planar actuator device using the same.

  Non-contact bearings include, for example, magnetic bearings, static pressure air bearings, dynamic pressure air bearings, and the like. A magnetic bearing is a bearing that uses the attractive force of a permanent magnet or an electromagnet to support the rotating shaft in space. However, since it cannot be established with a single permanent magnet, it can be combined with a permanent magnet and an electromagnet or with a single electromagnet. A position sensor for control, its signal processing circuit, an amplifier for an electromagnet, and the like are required, and the apparatus is complicated, large, and expensive. The static pressure air bearing is a bearing that ejects compressed air to the guide and floats by the generated static pressure. However, a compressor that supplies the compressed air is essential, and the compressed air piping is obstructive. A hydrodynamic air bearing is a bearing that supports the rotating shaft by drawing the surrounding air into the bearing clearance as the shaft rotates, but does not require compressed air. Sometimes the contactless support function is lost. These non-contact bearings are characterized by long life, low noise, high-precision rotation control, and maintenance-free.

The squeeze air bearing is a bearing that is supported in a non-contact manner by using a squeeze air film generated by a high-frequency vibration in a relative vertical direction between two opposing surfaces. For example, a piezoelectric element can be adopted as the vibrator, but other than that, only an amplifier for driving the piezoelectric element is required, and unlike the magnetic bearing, the apparatus is not complicated. Also, unlike a static pressure air bearing, unlike a hydrostatic air bearing, a non-contact support function is not lost even when rotating at low speed or stationary (unlike a hydrostatic air bearing).
In FIG. 8, 101 is a vibrating body, 102 is a floating body, and 103 is a gap. An air film is formed in a minute gap 103 between the vibrating body 101 and the floating body 102 to generate a non-contact support function. This is because the gas has viscosity, and if the vibration frequency of the vibrating body 101 is high, the flow of air around the air film in the gap 103 is restrained, as if a high-frequency volume change was caused in the sealed compressible fluid. It will be the same. If the frequency of the vibrating body 101 is high at that time, the levitated body 102 cannot follow due to inertial force and hardly vibrates, the pressure generation with respect to the displacement becomes non-linear, an average positive pressure is obtained, and the levitated body 102 is non-contacted. Supported on the vibrating body 101.

In addition, there is a squeeze air bearing that attempts to support the radial direction and the thrust direction simultaneously with a squeeze air film.
In FIG. 9, 201 is a vibrator, 202 is a vibration part, 203 is a vibration surface, 204 is a rotating shaft, 205 is a gap, and 206 is a fixed part. The vibration surface 203 vibrates at a high frequency due to vibration generated by the vibrator 204. When this is done, a squeezed air film is generated in the gap 205, and the rotating shaft 204 is supported in a non-contact manner.

There are compound bearings that combine the squeeze air film force and the repulsive force between permanent magnets.
In FIG. 10, 301 is a vibrator, 302 is a vibration part, 303 is a vibration surface, 304 is a movable part, 305 is a gap, 306 and 307 are permanent magnets. A squeezed air film is generated in the gap 305 between the surface 303 and the movable portion 304, and is thereby supported in a non-contact manner in the thrust direction. On the other hand, the permanent magnet 306 and the permanent magnet 307 have the same poles facing each other, and the repulsive force supports the movable portion 304 in a non-contact manner in the radial direction.

In addition, a plate-like vibrator is used as a thrust vibrator, and a squeezed air film is formed between the end face of the rotor and the flange face to form a thrust bearing, and the radial or cylindrical inner surface of the radial vibrator. A squeeze air bearing that has a simple configuration and is easy to manufacture has been proposed in which a squeeze air film is formed between the shaft and the shaft (see, for example, Patent Document 2).
In FIG. 11, 401 is a vibrator, 402 is a thrust vibrator, 403 is a thrust gap, 404 is a radial vibrator, 405 is a radial gap, and 406 is a rotating shaft. The squeeze air film generated in the radial gap 405 between the radial vibrator 404 and the rotary shaft 406 in the thrust direction by the squeeze air film generated in the thrust gap 403 between the vibrator 402 and the rotary body 406 Thus, the rotating body 406 is supported in a non-contact manner in the radial direction.

Also, by forming a spherical concave or convex portion on at least one end surface of the rotating shaft and making the vibration surface of the vibrator facing this convex or concave, the assembly accuracy may not be strict, and the number of parts There has been proposed a squeeze air bearing that can reduce the number of squeeze air bearings (see, for example, Patent Document 3).
In FIG. 12, 501 is a vibrator, 502 is a rotation axis, 503 is a recess, 504 is a gap, 505 is a fixed part, and when the vibrator 501 is vibrated, a gap between the vibrator 501 and the recess 503 of the rotor. A squeeze air film is generated in 504, and the rotating shaft 502 is supported in a radial and thrust direction in a non-contact manner.

  Conventional planar actuator devices using non-contact bearings can be driven and positioned with high precision by using magnetic bearings, air bearings, etc. as a support mechanism, with low vibration and noise, very little mechanical loss, and support. A planar actuator device has been proposed in which the mechanism has a long life and does not require maintenance (for example, see Patent Document 4).

As a conventional planar actuator device using a squeeze air bearing, a small and stable planar actuator has been proposed that does not require a large incidental facility while maintaining the advantages of a non-contact bearing (see, for example, Patent Document 5).
Japanese Patent Application Laid-Open No. Sho 62-255613 (Page 1-3, FIG. 1, FIG. 5, FIG. 6) Japanese Patent Laid-Open No. 01-203714 (page 2-4, FIG. 2) JP 02-142919 A (page 2-3, FIG. 2) JP 59-110366 (page 1-2, FIG. 1) JP 05-328702 A (page 2-3, FIG. 1)

The conventional squeeze air bearing has a squeeze air film with a thickness as small as 10 μm or less, and it is necessary to finish the plane or conical surface with high accuracy so as to maintain a gap of μm order. There was a problem.
Moreover, since the opposing surfaces are flat surfaces, cylindrical uneven surfaces, or spherical uneven surfaces, and the distance between the surfaces is constant, the processing accuracy of both surfaces must be increased. there were.
Further, in the case of cylindrical uneven surfaces or spherical uneven surfaces, there is a problem that they are not used for bearings such as linear motors and planar actuators that freely move on a plane.

Conventional planar actuator devices using non-contact bearings have a problem that the incidental facilities are large and complicated.
Further, since the flying distance is short, there is a problem that required machining and assembly accuracy are high and sensitive to the fluctuation.

  The present invention has been made in view of such problems, and includes a vibration surface that is not a plane that is vibrated by a vibrator and a plane that is opposed to the surface through a minute gap, and is non-contacted by a squeeze air film force. Therefore, it is an object of the present invention to provide a small, simple, and highly accurate planar actuator device that does not require a squeeze air bearing with increased squeeze air film force and a large incidental facility.

In order to solve the above problems, the present invention is configured as follows.
The squeeze air bearing according to claim 1, wherein the squeeze air bearing includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. The vibration surface is not flat.
The squeeze air bearing according to claim 2 is provided with a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. The vibration surface is provided with a concave portion and / or a convex portion.
According to a third aspect of the present invention, the squeeze air bearing has a convex portion on the outer peripheral portion of the vibration surface.
According to a fourth aspect of the present invention, the squeeze air bearing has a concave portion on an outer peripheral portion of the vibration surface.
The squeeze air bearing according to claim 5 is a squeeze air bearing that includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. The vibration surface has an inclined surface, and the distance from the opposed plane continuously changes.
The squeeze air bearing according to claim 6 is a squeeze air bearing that includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. In addition, a plurality of grooves are provided in a portion that is more than half of the area ratio of the vibration surface.
In the squeeze air bearing according to claim 7, the vibrator is formed of a piezoelectric element or an electrostatic electrode.
The squeeze air bearing according to claim 8 is a squeeze air bearing that includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. A vibration surface amplitude enlarging mechanism is provided between the vibrator and the vibration surface.
Further, in the squeeze air bearing according to claim 9, in the vibration surface amplitude enlarging mechanism, one end of the vibration direction is fixed to the case, the other end is fixed to the plate, the vibrator, and the plate is attached to the case. A fixed first flat plate and a second flat plate connected to the first flat plate are provided.
In the squeeze air bearing according to claim 10, the second flat plate has higher rigidity than the first flat plate.
The squeeze air bearing according to claim 11 is a squeeze air bearing that includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. The vibration center of the vibrator and the vibration centers of the first and second flat plates are coaxial.
In the squeeze air bearing according to claim 12, the vibration centers of the first and second flat plates coincide with the center of gravity of the case and the vibration center of the plate.
Further, the planar actuator device according to claim 13 is provided with a squeeze air bearing that is supported in a non-contact manner by utilizing a squeeze air film force generated by a high-frequency vibration in a relative vertical direction between two opposing surfaces. In the apparatus, at least four of the squeeze air bearings are arranged symmetrically with respect to the center of the slider of the planar actuator.
Further, in the planar actuator device according to claim 14, the squeeze air bearing is disposed on a side wall of a moving element of the planar actuator.
In the planar actuator device according to claim 15, the squeeze air bearing is disposed so as to be flush with the moving surface of the planar actuator with respect to the opposing surface.
The planar actuator device according to claim 16, further comprising a squeeze air bearing that is supported in a non-contact manner by utilizing a squeeze air film force generated by a relative vertical high-frequency vibration between two opposing surfaces. In the apparatus, the vibration surface of the squeeze air bearing is not flat.
The squeeze air bearing according to claim 17 is a squeeze air bearing that includes a vibration surface that is vibrated by a vibrator and a plane that is opposed to the vibration surface through a minute gap, and is supported in a non-contact manner by a squeeze air film force. A vibration surface amplitude enlarging mechanism between the vibrator and the vibration surface, wherein the vibration surface amplitude enlarging mechanism has one end in a vibration direction fixed to a case and the other end fixed to a plate. A first flat plate fixed to the case, and a second flat plate connected to the first flat plate, and the second flat plate is made of an iron-based metal. is there.
In the squeeze air bearing according to claim 18, the first flat plate is made of a titanium alloy, an aluminum alloy, or a magnesium alloy.
In the squeeze air bearing according to claim 19, the flat plate of the aluminum alloy and the titanium alloy is made of a superplastic alloy.
The squeeze air bearing according to claim 20, wherein the superplastic alloy is a zinc alloy containing 22% by mass of aluminum, an aluminum alloy containing 6% by mass of copper and 0.5% by mass of zirconium, 6% by mass. % Of aluminum and 4% by mass of vanadium-containing titanium alloy.
The squeeze air bearing according to claim 21 is such that the first flat plate is made of a titanium alloy containing 30 to 60% by mass of a vanadium group element.
The squeeze air bearing according to claim 22 is configured such that the titanium alloy contains 1 to 20% by mass in total of one or more elements in a metal element group composed of zirconium, hafnium, and scandium. Is.
The squeeze air bearing according to claim 23 is configured such that the titanium alloy contains 0.08 to 0.6% by mass of oxygen.
The squeeze air bearing according to claim 24, wherein the first flat plate is made of metallic glass having an elastic strain of 0.015 to 0.03 obtained by dividing a tensile strength by an elastic modulus and a tensile strength of 750 MPa or more. It has been done.
Further, in the squeeze air bearing according to claim 25, the metallic glass is composed of one containing 5 to 60% by mass of zirconium and nickel in the balance.

According to the squeeze air bearing of claim 1, by eliminating the vibration surface from a flat surface, the squeeze air film force can be increased, the processing and assembly accuracy of the vibration surface and the opposing flat surface can be lowered, and the fluctuation of the gap can be reduced. It can be stabilized.
Further, according to the squeeze air bearing of claim 2, the squeeze air film force can be increased by providing the vibration surface with a concave portion and / or a convex portion.
According to the squeeze air bearing of claim 3, by providing the convex portion on the outer peripheral portion of the vibration surface, the convex portion becomes a kind of resistance for the squeeze air film generated in the gap between the opposing planes. Therefore, the squeeze air film force can be increased by enhancing the sealing effect.
According to the squeeze air bearing of the fourth aspect, by providing the concave portion on the outer peripheral portion of the vibration surface, the concave portion becomes a turbulent flow generation source for the squeeze air film generated in the gap between the opposing planes. By acting as a kind of air curtain and enhancing its sealing effect, the squeeze air film force can be increased.
Further, according to the squeeze air bearing of claim 5, since it can be distributed in the positive pressure due to the squeeze air film force in the vibration surface, it has excellent characteristics for precise positioning by generating a force that maintains its position. Or by generating a force to start moving from that position, it is possible to have excellent characteristics in motion characteristics.
Further, according to the squeeze air bearing of claim 6, since it can be distributed in the positive pressure due to the squeeze air film force in the vibration surface, it has excellent characteristics for precise positioning by generating a force that maintains the position. Or by generating a force to start moving from that position, it is possible to have excellent characteristics in motion characteristics.
Further, according to the squeeze air bearing of the seventh aspect, it can be made small, light, simple and inexpensive.
According to the squeeze air bearing of claims 8 to 12, by providing the amplitude enlarging mechanism, the load rigidity can be increased and the squeeze air film force can be increased.
Further, according to the planar actuator device of the thirteenth to sixteenth aspects, a large-scale incidental facility is not required, and it is possible to achieve small size, simple and high precision driving and positioning.
In addition, according to the squeeze air bearings of claims 17 and 18, since the flat plate member is highly rigid and lightweight, it can improve mechanical properties, easily increase the resonance frequency, and perform precision machining. Since it is easy and inexpensive, the apparatus can be constructed with high accuracy and low cost.
According to the squeeze air bearing of claims 19 to 25, the first flat plate has low elasticity and high strength, and the life can be improved.

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

FIG. 1 is a cross-sectional view of a squeeze air bearing according to Embodiment 1 of the present invention. Here, 1 is a vibrator, 21 is a vibration surface, 22 is a convex portion having a semicircular cross-sectional shape, 3 is a facing plane, and 4 is a gap between the plane 3 facing the vibration surface 21.
The part where the present invention is different from Patent Documents 1, 2, and 3 is a part where one of the surfaces facing the vibration surface vibrated by the vibrator is not a flat surface and the clearance between the outer peripheral portions of the vibration surface is narrow. That is, as shown in FIG. 1, the cross-sectional shape that is vibrated by the vibrator 1 is constituted by a vibration surface 21 having a semicircular convex portion 22 and a plane 3 that faces the gap 4. Here, when the vibration frequency of the vibrator 1 is high, the air in the gap 4 is viscous, so that the surrounding air is restricted from entering and exiting, as if a high-frequency volume change was caused in the sealed compressible fluid. The pressure generation with respect to the displacement becomes non-linear, a positive pressure is obtained on average, and is supported in a non-contact manner. In the present invention, the convex portion 22 on the outer peripheral portion of the vibration surface 21 becomes a kind of resistance to the air flow, the movement of the air in the gap 4 is further restricted, the squeeze air film force is increased, and the non-contact air bearing The performance of will be higher. Since the squeeze air film force is increased by the convex portion 22 on the outer peripheral portion, the machining and assembling accuracy of the vibration surface 21 and the opposing flat surface 3 can be lowered, and the fluctuation of the gap 4 is stable.

FIG. 2 is a cross-sectional view of a squeeze air bearing according to Embodiment 2 of the present invention. Here, 1 is a vibrator, 21 is a vibrating surface, 23 is a convex portion having a rectangular cross-sectional shape, 3 is a facing plane, and 4 is a gap between the plane 3 facing the vibrating surface 21.
As shown in FIG. 2, the same effect as in Example 1 was also obtained when the outer peripheral portion of the vibration surface 21 had a convex portion having a rectangular cross-sectional shape. In other words, the present invention is not limited to the shape of the convex portion as long as the convex portion brings about the effect of preventing the movement of air in the gap on the outer peripheral portion of the vibration surface.

FIG. 3 is a cross-sectional view of a squeeze air bearing according to Embodiment 3 of the present invention. Here, 1 is a vibrator, 21 is a vibrating surface, 24 is a concave part having a semicircular cross-sectional shape, 3 is a facing plane, and 4 is a gap between the plane 3 facing the vibrating surface 21.
A portion where the present invention is different from Patent Documents 1, 2, and 3 is a portion where any of the surfaces facing the vibration surface vibrated by the vibrator is not a flat surface, and the clearance between the outer peripheral portions of the vibration surface is wide. That is, as shown in FIG. 3, the cross-sectional shape that is vibrated by the vibrator 1 is constituted by the vibration surface 21 having the semicircular recess 24 and the plane 3 that faces the gap 4. Here, when the vibration frequency of the vibrator 1 is high, the air in the gap 4 is viscous, so that the surrounding air is restricted from entering and exiting, as if a high-frequency volume change was caused in the sealed compressible fluid. The pressure generation with respect to the displacement becomes non-linear, a positive pressure is obtained on average, and is supported in a non-contact manner. In the present invention, the air flow in the gap 4 becomes a turbulent flow due to the concave portion 24 on the outer peripheral portion of the vibration surface 21, which acts as a kind of air curtain against the air flow, and the movement of the air in the gap 4 is more restricted. Thus, the squeeze air film force is increased, and the performance as a non-contact air bearing is further increased.

FIG. 4 is a cross-sectional view of a squeeze air bearing according to Embodiment 4 of the present invention. Here, 1 is a vibrator, 21 is a vibration surface, 25 is a recess having a rectangular cross-sectional shape, 3 is a facing plane, and 4 is a gap between the plane 3 facing the vibration surface 21.
As shown in FIG. 4, the same effect as in Example 3 was obtained when the outer peripheral portion of the vibration surface 21 was provided with a recess having a rectangular cross-sectional shape. In other words, the present invention is not limited to the shape of the recess as long as the recess has an effect of generating a turbulent flow in the gap and hindering air movement at the outer peripheral portion of the vibration surface.

  As described above, in Examples 1 to 4, the example in which the outer peripheral portion of the vibration surface is provided with the concave portion or the convex portion has been described, but the present invention is effective even when both the concave portion and the convex portion are provided. Moreover, although the case where a recessed part or a convex part is the outermost periphery part of a vibration surface and the case where there exists a space in the outer side of a recessed part or a convex part are considered, in this invention, it is not essential and either may be sufficient.

5 and 6 are cross-sectional views of the squeeze air bearing according to the fifth embodiment of the present invention. Here, 1 is a vibrator, 21 is a vibration surface, 26 is a taper portion, 27 is a reverse taper portion, 3 is a facing plane, and 4 is a gap between the plane 3 facing the vibration surface 21.
The part where the present invention is different from Patent Documents 1, 2, and 3 is that the surface facing the vibrating surface vibrated by the vibrator is not a flat surface, and the vibration surface has a tapered portion or a reverse tapered portion. This is a portion in which a change is made in the gap between the flat surface. That is, as shown in FIG. 5, it is constituted by the plane 3 that faces the vibration surface 21 having the taper portion 26 or the reverse taper portion 27 that is vibrated by the vibrator 1 through the gap 4. Here, when the vibration frequency of the vibrator 1 is high, the air in the gap 4 is viscous, so that the surrounding air is restricted from entering and exiting, as if a high-frequency volume change was caused in the sealed compressible fluid. The pressure generation with respect to the displacement becomes non-linear, a positive pressure is obtained on average, and is supported in a non-contact manner. In the present invention, since the taper portion 26 or the reverse taper portion 27 of the vibration surface 21 can be distributed in the positive pressure due to the squeezed air film force in the vibration surface, precise positioning is achieved by generating a force that maintains the position. It is possible to provide a characteristic excellent in the movement characteristic by giving a superior characteristic to the movement or generating a force to move from the position.

FIG. 7 is a cross-sectional view of a squeeze air bearing according to Embodiment 6 of the present invention. Here, 1 is a vibrator, 21 is a vibration surface, 28 is a groove part, 3 is an opposing plane, and 4 is a gap between the plane 3 facing the vibration surface 21.
The difference between the present invention and Patent Documents 1, 2, and 3 is that any of the surfaces facing the vibration surface that is vibrated by the vibrator is not a flat surface but has a groove on the vibration surface. That is, as shown in FIG. 7, the vibration surface 21 vibrated by the vibrator 1 is constituted by a plane 3 that opposes the vibration surface 21 having a plurality of grooves in a portion that is more than half of the area ratio of the vibration surface through the gap 4. The Here, when the vibration frequency of the vibrator 1 is high, the air in the gap 4 is viscous, so that the surrounding air is restricted from entering and exiting, as if a high-frequency volume change was caused in the sealed compressible fluid. The pressure generation with respect to the displacement becomes non-linear, a positive pressure is obtained on average, and is supported in a non-contact manner. In the present invention, the groove portion 28 of the vibration surface 21 becomes a kind of resistance to the air flow, the movement of the air in the gap 4 is more restricted, the sealing performance is enhanced, the squeeze air film force is increased, and the non-contact air bearing The performance of will be higher.

  In the above description of the embodiment of the present invention, an example in which a piezoelectric element or an electrostatic electrode is used for the vibrator 1 has been described. However, the vibrator 1 according to the present invention only needs to vibrate the vibration surface 21. It is not limited to the type or method.

  FIG. 8 is a side sectional view of the squeeze air bearing of the present invention. In the figure, 601 is a piezoelectric element, 602 is a dish, 603 and 604 are disks, 605 is a case, 606 is a load, 607 is a fixing screw, 608 is a cap bolt, 609 is an opposing surface, and 610 is a vibration surface. When a voltage having an amplitude of several tens of volts and a period of several kilohertz is input to the piezoelectric element 601, the piezoelectric element 601 is displaced in proportion to the voltage. This displacement displaces the plate 602 in contact with the piezoelectric element 601. Displacement of the plate 602 displaces the disk 603 in contact with the plate 602. Since the disk 603 is coupled to the case 605 by the fixing screw 607, the displacement is 0 at the point A1 in FIG. 8, and the displacement is the same as that of the piezoelectric element 601 at the point A2. If this disk 603 is a thin plate or has a low rigidity, the displacement at the point B1 in FIG. 8 is zero while the displacement at the cap bolt 608 is increased by the relationship of the expression (1).

Where d1 is the vertical displacement at point A2, d2 is the vertical displacement at point B2, A is the distance from point A1 to point A2, and B is the distance from point B1 to point B2. .

  Even with the disk 603 alone, the amount of vertical displacement at the point B2 can be increased from the equation (1), but the disk 603 and the disk 604 are fixed with cap bolts 608 in order to increase the amount of displacement over a wide range. Unlike the disk 603, the disk 604 uses a material having high rigidity. More specifically, the disk 604 is made of an iron-based metal material such as various carbon steels including S45C and various stainless steels including SUS304. The disk 603 was made of an aluminum alloy such as A2017, a magnesium alloy such as AZ80, or a titanium alloy such as Ti-6Al-4V. Furthermore, Ti-35Nb-10V-0.35O, Ti-40Nb-6V-4Ta-0.28O, Ti-20Nb-5V-10Ta-5Zr-5Hf-0.29O, Ti-35Nb-5Ta-3Sc-0. Metal alloys such as titanium alloy such as 27O and superplastically processed Zn-22Al, Al-6Cu-0.5Zr, Zr-30Cu-10Al-5Ni, and Ni-20Nb-10Ti-8Zr-6Co-3Cu were used. A squeeze film is generated between the vibration surface 609 which is the upper surface of the disk 604 and the opposing surface 610 which is the lower surface of the load 606, and the load 606 is levitated.

  FIG. 9 is a side cross-sectional view of FIG. 8 upside down, showing that the squeeze air bearing floats with respect to the facing surface 609 which is a fixed end. Therefore, the lower surface of the disk 604 is the vibration surface 610. The amplitude expansion is the same as that in the first embodiment, and thus the description thereof is omitted. Here, the floating principle of the dynamic pressure type air vibration surface using the squeeze effect will be described. This description will be described with reference to non-patent literature. The equation of motion of the dynamic pressure type air vibrating surface using the squeeze effect can be expressed by equation (2).

Here, the variables of the equations (2) and (3) are a ₀ : amplitude of the piezoelectric element, h: air film thickness, m: mass of the vibration surface, M: load mass, p ₀ : ambient pressure, p: squeeze. Membrane pressure, r: radial coordinate of vibration surface, r ₀ : vibration surface radius, ω: piezoelectric element excitation acceleration.

  The left side of equation (2) represents an equation of motion with the piezoelectric element displacement as a variable, and the right side of equation (2) is the equation of motion related to pressure. A force is generated when the vibration surface changes with time, and this force is equivalent to the equation for pressure change. Therefore, the vibration surface rises due to the squeeze film pressure. Since the pressure can be expressed as a force per unit area, it can be interpreted that the displacement of the piezoelectric element causes a pressure change between the vibration surface and the opposing surface. In the present invention, the displacement of the vibration surface is enlarged using an amplitude enlargement mechanism. When this is applied to the left side of Equation (2), the force on the left side increases more than when there is no amplitude expansion mechanism. This increased force needs to be balanced with the right side of equation (2), and the area of the vibration surface does not increase, so the pressure in the integration increases. Since the ambient pressure does not change, the squeeze film pressure increases. Since the levitation rigidity can be improved by increasing the squeeze film pressure, it is possible to levitate by providing an amplitude expansion mechanism even with a load that has been difficult to levitate conventionally. When the disk 603 is made of an aluminum alloy such as A2017, a magnesium alloy such as AZ80, or a titanium alloy such as Ti-6Al-4V, the squeeze air bearing can be manufactured at low cost. Meanwhile, Ti-35Nb-10V-0.35O, Ti-40Nb-6V-4Ta-0.28O, Ti-20Nb-5V-10Ta-5Zr-5Hf-0.29O, Ti-35Nb-5Ta-3Sc-0. When a metallic glass such as titanium alloy such as 27O or Zn-22Al, Al-6Cu-0.5Zr and Zr-30Cu-10Al-5Ni or Ni-20Nb-10Ti-8Zr-6Co-3Cu subjected to superplastic processing is used, The life in use was more than doubled compared to the case of using aluminum alloys including A2017, magnesium alloys including AZ80, and titanium alloys including Ti-6Al-4V.

The squeeze air bearing described in Examples 1 to 7 was a non-contact bearing of a planar actuator device. FIG. 10 shows a top view and a side view of a planar actuator device provided with a squeeze air bearing.
The part from which this invention differs from patent document 4 is a part in which the provided non-contact bearing is a squeeze air bearing. Further, the present invention is different from Patent Document 5 in that any of the surfaces facing the vibrating surface that vibrates by the vibrator of the squeezed air bearing which is a non-contact bearing provided is not a flat surface, and the squeezed air film force characteristics are improved. The squeezed air film force characteristic is improved by providing the portion and the amplitude expanding mechanism. In other words, the use of the squeeze air bearing as the non-contact bearing eliminates the need for a large incidental facility, enables a small and simple device, and enables high-precision driving and positioning.
In FIG. 10, reference numeral 701 denotes a mover, 702 denotes a squeeze air bearing unit of the second embodiment, 703 denotes a vibration surface, and 704 denotes an opposing surface. Four units 702 are coupled to the mover 701 so that the side walls of the mover 701 are opposed to each other, and are arranged so as to be flush with the mover 701 with respect to the facing surface 704. 4 This unit 702 causes the mover 701 and the unit 702 to float. If the movable element 701 is a planar actuator device, for example, a displacement sensor for positioning is attached to the movable element 701 on the vibration surface 703 side. Further, a stator and a glass scale are attached to the facing surface 704 side. If the floating rigidity is insufficient, a unit 702 can be added and attached to the side surface of the mover 701.

  In the above description of the embodiment of the present invention, the planar actuator device has been described as an example. However, it is needless to say that the linear motor is also effective, and the present invention is not limited to the device to which the squeeze air bearing is applied.

  The squeeze air bearing of the present invention is a non-contact bearing because it is small and light, simple, low in machining and assembly accuracy, stable against gap fluctuations, inexpensive, and excellent in squeeze air film pressure characteristics. The present invention can be applied to various actuator devices typified by planar actuator devices and linear motors.

Sectional drawing of the squeeze air bearing which shows 1st Example of this invention Sectional drawing of the squeeze air bearing which shows 2nd Example of this invention. Sectional drawing of the squeeze air bearing which shows 3rd Example of this invention. Sectional drawing of the squeeze air bearing which shows 4th Example of this invention. Sectional drawing of the squeeze air bearing which shows 5th Example of this invention. Sectional drawing of the squeeze air bearing which shows 5th Example of this invention. Sectional drawing of the squeeze air bearing which shows 6th Example of this invention Side sectional view of a squeeze air bearing showing a seventh embodiment of the present invention. Side sectional view of a squeeze air bearing showing an eighth embodiment of the present invention. Top view and side view of planar actuator device of the present invention Cross-sectional view of a conventional squeeze air bearing Cross-sectional view of a conventional squeeze air bearing Cross-sectional view of a conventional squeeze air bearing Cross-sectional view of a conventional squeeze air bearing Cross-sectional view of a conventional squeeze air bearing

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibrator 21 Vibrating surface 22 Convex part 23 Convex part 24 Concave part 25 Concave part 26 Taper part 27 Reverse taper part 28 Groove part 3 Opposite plane 4 Gap 101 Vibrator 102 Floating body 103 Gap 201, 301, 401, 501 Vibrator 202, 302 Vibrating parts 203, 303 Vibrating surfaces 204, 406, 502 Rotating shafts 205, 305, 504 Clearances 206, 505 Fixed parts 304 Movable parts 306, 307 Permanent magnet 402 Thrust vibrator 403 Thrust gap 404 Radial vibrator 405 Radial Clearance 503 Recess 601 Piezoelectric element 602 Dish plate 603, 604 Disc 605 Case 606 Load 607 Fixing screw 608 Cap bolt 609, 704 Opposing surface 610, 703 Vibration surface 701 Movable element 702 Unit

Claims (25)

In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
The squeeze air bearing, wherein the vibration surface is not a flat surface. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
A squeeze air bearing, wherein the vibration surface is provided with a concave portion and / or a convex portion.   The squeeze air bearing according to claim 2, wherein a convex portion is provided on an outer peripheral portion of the vibration surface.   The squeeze air bearing according to claim 2, wherein a concave portion is provided on an outer peripheral portion of the vibration surface. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
The squeeze air bearing according to claim 1, wherein the vibration surface has an inclined surface, and the vibration surface has a continuously changing distance from the opposed flat surface. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
A squeeze air bearing characterized in that it has a plurality of grooves in a portion that is more than half the area ratio of the vibration surface.   The squeeze air bearing according to claim 1, wherein the vibrator includes a piezoelectric element or an electrostatic electrode. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
A squeeze air bearing comprising a vibration surface amplitude enlarging mechanism between the vibrator and the vibration surface.   The vibration surface amplitude enlarging mechanism has one end in the vibration direction fixed to the case, the other end fixed to the dish plate, the vibrator, the first flat plate with the dish plate fixed to the case, and the first The squeeze air bearing according to claim 8, further comprising a second flat plate connected to the flat plate.   The squeeze air bearing according to claim 8, wherein the second flat plate has higher rigidity than the first flat plate. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
The squeeze air bearing characterized in that the vibration center of the vibrator and the vibration centers of the first and second flat plates are coaxial.   12. The squeeze air bearing according to claim 11, wherein the vibration centers of the first and second flat plates coincide with the center of gravity of the case and the vibration center of the dish plate. In a planar actuator device provided with a squeeze air bearing that is supported in a non-contact manner by utilizing a squeeze air film force generated by a high-frequency vibration in a vertical direction between two opposing surfaces,
A planar actuator device, wherein at least four of the squeeze air bearings are arranged symmetrically with respect to the center of the slider of the planar actuator.   The planar actuator device according to claim 13, wherein the squeeze air bearing is disposed on a side wall of a slider of the planar actuator.   The planar actuator device according to claim 13, wherein the squeeze air bearing is disposed so as to be flush with a moving element of the planar actuator with respect to an opposing surface. In a planar actuator device provided with a squeeze air bearing that is supported in a non-contact manner by utilizing a squeeze air film force generated by a high-frequency vibration in a vertical direction between two opposing surfaces,
A planar actuator device, wherein a vibration surface of the squeeze air bearing is not flat. In a squeeze air bearing comprising a vibration surface to be vibrated by a vibrator and a plane opposed to the surface through a minute gap, and supported in a non-contact manner by a squeeze air film force,
A vibration surface amplitude enlarging mechanism is provided between the vibrator and the vibration surface, and the vibration surface amplitude enlarging mechanism has one end in the vibration direction fixed to the case and the other end fixed to the dish plate. The dish plate includes a first flat plate fixed to the case, and a second flat plate connected to the first flat plate, and the second flat plate is made of an iron-based metal. And squeeze air bearing.   The squeeze air bearing according to claim 17, wherein the first flat plate is made of a titanium alloy, an aluminum alloy, or a magnesium alloy.   The squeeze air bearing according to claim 18, wherein the aluminum alloy and the titanium alloy are made of a superplastic alloy.   The superplastic alloy contains a zinc alloy containing 22% by weight of aluminum, an aluminum alloy containing 6% by weight of copper and 0.5% by weight of zirconium, 6% by weight of aluminum and 4% by weight of vanadium. The squeeze air bearing according to claim 19, wherein the squeeze air bearing is any one of titanium alloys.   The squeeze air bearing according to claim 18, wherein the first flat plate is made of a titanium alloy containing 30 to 60 mass% of a vanadium group element.   The squeeze air bearing according to claim 21, wherein the titanium alloy contains 1 to 20 mass% in total of one or more elements in a metal element group composed of zirconium, hafnium, and scandium.   The squeeze air bearing according to claim 22, wherein the titanium alloy contains 0.08 to 0.6 mass% oxygen.   The said 1st flat plate was comprised with the metallic glass whose elastic strain which remove | divided the tensile strength by the elasticity modulus is 0.015-0.03, and whose tensile strength is 750 Mpa or more. Squeeze air bearing.   25. The squeeze air bearing according to claim 24, wherein the metallic glass contains 5 to 60% by mass of zirconium and the remainder contains nickel.