JP2007321811A - Non-contact supporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact supporting device reducible in size. <P>SOLUTION: A squeeze air bearing 10 has a piezoelectric element 16 driven to generate ultrasonic vibration, and a horn 20 coaxially holding the piezoelectric element 16 between one axial end face 40A and a metal block 18. The horn 20 is vibrated by the piezoelectric element 16 to support a rotating float 12 in a non-contact manner via a squeeze air film which is formed between a supporting face 42A formed on an outer peripheral portion and the rotating float 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-contact support device for supporting a supported body in a non-contact manner.

A squeeze air bearing using ultrasonic vibration is known as a rotation guide element of a machine (see, for example, Non-Patent Document 1). This squeeze air bearing has a bolted Langevin type ultrasonic transducer in which a pair of metal blocks sandwiching a piezoelectric element are connected by bolts, and one end surface in the axial direction is the ultrasonic transducer (the end surface of one metal block) And a horn joined to each other. The horn supports the rotating levitation body in the thrust direction with an air film formed between the other end face and the rotating levitation body by the operation of the ultrasonic vibrator, and also includes the outer peripheral surface of the enlarged diameter portion and the inner surface of the rotating levitation body. The rotary levitation body is supported in the radial direction by an air film formed between the peripheral surface and the peripheral surface.
Oiwa, Kato, "Active Air Bearing Using Ultrasonic Vibration (5th Report)-Trial Production of Air Bearing Using Vibration Direction Changer", 15th Symposium on "Electromagnetic Force Related Dynamics", May 2003 30 days JP 2006-84018 A

  However, in the conventional techniques as described above, there is room for improvement with respect to downsizing of the apparatus.

  An object of the present invention is to obtain a non-contact support device that can be reduced in size in consideration of the above facts.

  In order to achieve the above object, a non-contact support device according to the first aspect of the present invention includes an exciter that is driven to generate ultrasonic vibrations, and an exciter between an end face in the axial direction and the first member. The body is sandwiched and held coaxially, and the non-contact state between the second member is maintained between the support surface formed on the outer peripheral portion and the second member by being vibrated by the vibrator. And a third member for generating an air film for the purpose.

  In the non-contact support device according to claim 1, when the vibration generator is driven to generate ultrasonic vibration, the ultrasonic vibration is transmitted to the third member, and the vibration in the radial direction based on the Poisson effect of the third member. Due to the direction changing action, the support surface formed on the outer peripheral portion of the third member is ultrasonically vibrated, and an air film (squeezed air film) is generated between the support surface and the second member. The air film supports the second member with respect to the third member or the third member with respect to the second member in a non-contact state. Here, in this non-contact support apparatus, since the 3rd member in which an air film is generated between the 2nd member has inserted the vibration body between the 1st member, in other words, the 3rd member Is in direct contact with the vibrator, for example, the axial dimension is smaller compared to a configuration with an ultrasonic vibrator with a piezoelectric element (vibrator) sandwiched between a pair of metal blocks. Can be

  Thus, the non-contact support device according to claim 1 can be downsized.

  A non-contact support device according to a second aspect of the present invention is the non-contact support device according to the first aspect, wherein the vibrator is a piezoelectric element capable of generating ultrasonic vibration due to a piezoelectric effect, and the third member is The vibrator is sandwiched between the first member and the first member in a compressed state.

  In the non-contact support device according to the second aspect, the vibrator as a piezoelectric element is sandwiched between the third member and the first member while receiving a preload. Thus, the non-contact support device is configured with a simple structure. For example, the first member and the third member can maintain a state in which the vibrator is sandwiched in a compressed state by fastening with a fastener.

  The non-contact support device according to a third aspect of the present invention is the non-contact support device according to the first or second aspect, wherein the third member is the support surface when the third member is vibrated by the vibrator. And the non-contact state with this 2nd member is maintained through the air film produced | generated between the other end surface of an axial direction, and the 2nd member.

  In the non-contact support device according to claim 3, the air film is generated between the other end surface of the third member and the second member, so that the third member and the second member are relative to each other in the axial direction. Displacement is regulated while maintaining a non-contact state.

  The non-contact support device according to a fourth aspect of the present invention is the non-contact support device according to any one of the first to third aspects, wherein the support surface of the third member is coaxial with the third member. It is a cylindrical surface.

  In the non-contact support device according to claim 4, since the support surface is a cylindrical surface, relative rotation between the third member and the second member is allowed, and the device can function as a rotation guide device.

  The non-contact support device according to a fifth aspect of the present invention is the non-contact support device according to any one of the first to fourth aspects, wherein the third member has a length in the axial direction. It is designed to be a natural number multiple of 1/4 of the wavelength of the ultrasonic wave that is vibrated by the body and propagates through the third member.

  In the non-contact support device according to claim 5, the contact surface (excitation surface) of the vibration generator in the third member having the above length becomes a vibration node. Thereby, the third member can be configured to be shortest while ensuring the amplitude of the support surface (the other end surface or the like). Further, if the length of the third member is ¼ of the above wavelength, the entire length of the apparatus can be shortened.

  A non-contact support device according to a sixth aspect of the present invention is the non-contact support device according to any one of the first to fifth aspects, wherein the third member protrudes in a direction orthogonal to the axis and has an outer periphery. A projecting portion having the support surface formed thereon.

  In the non-contact support device according to claim 6, the overhanging portion having a support surface serving as a radiation (output) surface of radial ultrasonic vibration is provided on the third member. In other words, the shaft of the overhanging portion is provided. Since there is no portion that inhibits the Poisson effect on both sides of the direction, the ultrasonic vibration input in the axial direction can be effectively converted into radial vibration.

  The non-contact support device according to a seventh aspect of the present invention is the non-contact support device according to the sixth aspect, wherein the overhanging portion is vibrated by the vibrator in the third member. It protrudes from the node position of the ultrasonic wave transmitted in the axial direction in a direction orthogonal to the axis of the third member.

  In the non-contact support device according to the seventh aspect, since the overhang portion projects from the node position of the ultrasonic vibration in the third member, the amplitude of the radial vibration of the support surface due to the Poisson effect increases. In particular, in the configuration in which the axial length of the third member is ¼ of the wavelength and the excitation surface by the exciter is a node of vibration, the overhanging portion is arranged in the immediate vicinity of the excitation surface, so the size is small. However, the amplitude of the radial vibration of the support surface due to the Poisson effect increases.

  The non-contact support device according to claim 8 is the non-contact support device according to claim 7, wherein the third member has a distance from the shaft center to the support surface of the overhanging portion. It is designed to be ¼ of the wavelength of the ultrasonic wave transmitted through the third member.

  In the non-contact support device according to claim 8, since the support surface is located at a position 1/4 of the wavelength from the node position of the axial vibration, the amplitude of the radial vibration of the support surface due to the Poisson effect is maximized. Can do. Further, the overhanging portion is reduced in size as compared with the configuration in which the support surface is disposed at a position that is an integral multiple of 1/4 of the wavelength.

  The non-contact support device according to a ninth aspect of the present invention is the non-contact support device according to any one of the sixth to eighth aspects, wherein the support surface of the overhang portion is vibrated on the vibrator. And formed on both sides in the axial direction with respect to the node position of the ultrasonic wave transmitted in the axial direction through the third member.

  In the non-contact support device according to claim 9, since the support surfaces are formed on both sides in the axial direction with respect to the node position of the ultrasonic vibration, the support surface is compared with a configuration in which the support surface is formed only on one side in the axial direction with respect to the node position. Thus, the range in which the amplitude of the support surface is large can be set widely. This contributes to an improvement in support rigidity. For example, in a configuration in which the first end surface in the axial direction of the third member in contact with the vibrator is a node in vibration, a part of the axial direction of the overhanging portion is at least a part of the axial direction of the vibrator. What is necessary is just to comprise so that it may cover from an outer peripheral side.

  A non-contact support device according to a tenth aspect of the present invention is the non-contact support device according to any one of the first to ninth aspects, wherein the support surface is a radially outer side and an axial direction of the third member. The taper surface which faces the one end side of both is included.

  In the non-contact support device according to the tenth aspect, the relative displacement of the second member and the third member in the other axial direction on the tapered surface can be regulated in a non-contact manner (the degree of freedom is restricted).

  The non-contact support device according to claim 11 is the non-contact support device according to any one of claims 1 to 10, wherein the third member is supported by a machine base and the second member. It is a support body which supports non-contact as a to-be-supported body.

  In the non-contact support device according to claim 11, since the third member to which ultrasonic vibration is directly input from the vibrator supports the second member as a support, the second member that is a supported body Residual vibration can be suppressed.

  A non-contact support apparatus according to a twelfth aspect of the present invention is the non-contact support apparatus according to the eleventh aspect, wherein the third member is supported by the machine base via the first member.

  In the non-contact support device according to claim 12, since the third member excited by the vibrator is not directly restrained with respect to the machine base, the ultrasonic vibration of the support surface of the third member is attenuated. Is prevented.

  A non-contact support device according to a thirteenth aspect of the present invention is the non-contact support device according to the twelfth aspect of the present invention, wherein the first member is a flange extending along an end surface in contact with the vibrator. It is fixed to the base.

  In the non-contact support device according to claim 13, since the flange extending from the portion near the vibration node in the first member is fixed to the machine base, the ultrasonic vibration of the support surface of the third member is attenuated. Is effectively prevented. In other words, it is possible to prevent the vibration of the vibrator constituted by the first member, the third member, and the vibrator from being attenuated.

  As described above, the non-contact support device according to the present invention has an excellent effect that it can be downsized.

  A squeeze air bearing 10 as a non-contact support device according to a first embodiment of the present invention will be described with reference to FIGS. In addition, the arrow U shown suitably in a figure represents the upper side of the gravity direction.

  FIG. 1 shows a schematic overall configuration of the squeeze air bearing 10 in a cross-sectional view. As shown in this figure, the squeeze air bearing 10 is a device that supports a rotating levitated body 12 as a second member or a supported member in a non-contact manner with respect to a machine base 14 so as to be rotatable around an axis, that is, a non-contact manner. It is grasped as a rotation guide means. This will be specifically described below.

  The squeeze air bearing 10 includes a piezo element 16 as a vibration body or a piezoelectric element, a metal block 18 as a first member, and a horn 20 as a third member with the piezo element 16 sandwiched between the metal block 18. The bolt 22 for fastening the metal block 18 and the horn 20 is a main component of the mechanical part.

  The piezo element 16 is made of ceramic or the like that generates displacement due to the piezoelectric effect, and is configured to generate ultrasonic vibrations upon application of an alternating voltage. In this embodiment, two piezo elements 16 are provided, each formed in a washer shape that can penetrate the bolt 22. Electrodes (not shown) are sandwiched between the two piezo elements 16 and between the lower piezo element 16 and the metal block 18, and an alternating (alternating current) voltage is applied to these electrodes. Each piezo element 16 is configured to generate ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage. In this embodiment, the alternating signal generated by the transmitter 26 is amplified by the amplifier 28, further converted into a voltage by the converter 30, and applied to the electrode, that is, the piezo element 16.

  The metal block 18 is configured like a nut by forming a female thread portion 35 in a through hole 34 penetrating the axial center portion of the block main body 32 formed in a substantially cylindrical shape. The outer diameter of the block body 32 is equal to or slightly larger than the outer diameter of the piezo element 16. A flange 36 projects radially outward from an upper end surface 32A, which is one end side of the block body 32 in the axial direction. The flange 36 may be formed in a ring shape over the entire circumference of the block body 32 or may partially protrude in the circumferential direction. The metal block 18 is fixedly supported on the machine base 14 via a plurality of support columns 38 at the flange 36. That is, each column 38 has an upper end 38 </ b> A fixed to the flange 36 and a lower end 38 </ b> B fixed to the machine base 14.

  The horn 20 includes a longitudinal vibration transmitting portion 40 formed in a substantially cylindrical shape, and a lateral vibration transmitting portion 42 as a projecting portion provided to project radially outward from the lower end side of the longitudinal vibration transmitting portion 40. It consists of The longitudinal vibration transmitting portion 40 has an outer diameter equal to or slightly larger than the outer diameter of the piezo element 16, and a female screw 45 is formed in a screw hole 44 that opens downward in the axial center portion of the longitudinal vibration transmitting portion 40. It is formed in a shape. The horn 20 has a lower end surface 40A of the longitudinal vibration transmitting portion 40 and the metal block 18 connected to the female screw 45 by screwing the other end of the bolt 22 whose one end is screwed to the female screw 35 of the metal block 18. Each piezo element 16 and the electrode are coaxially sandwiched between the upper end surface 32A of the block main body 32 to be configured. That is, the piezo element 16, the metal block 18, the horn 20, and the electrodes are fixed to each other by fastening using the bolts 22. In this fastened state, a predetermined pre-pressure (compression displacement) is applied to the piezo element 16.

  Therefore, in the squeeze air bearing 10 according to this embodiment, the piezo element 16, the metal block 18, the horn 20, the bolt 22, and the electrode replace one metal block with the horn 20, or replace one horn with the horn 20. It can be understood that a so-called bolted Langevin type ultrasonic transducer is constructed.

  2, the longitudinal vibration transmitting portion 40 of the horn 20 has a length L along the axial direction from the lower end surface 40A to the upper end surface 40B, and the horn 20 is vibrated by the piezo element 16. Is approximately ¼ of the wavelength λ of the ultrasonic vibration propagating through. Here, when the ultrasonic vibration propagating in the axial direction through the horn 20 by the vibration of the piezoelectric element 16 of this embodiment is considered as a longitudinal wave (hereinafter referred to as ultrasonic longitudinal vibration Vl (see FIG. 2)), the wavelength λ ( m) is determined by the frequency f (Hz) of the ultrasonic wave propagating through the horn 20 and the sound velocity C (m / s) of the longitudinal wave propagating through the horn 20. Thereby, in the longitudinal vibration transmission part 40, the upper end surface 40B becomes the antinode position of the ultrasonic longitudinal vibration Vl (the position where the amplitude in the axial direction becomes maximum), while the lower end surface 40A has the ultrasonic longitudinal vibration Vl described above. This is the configuration of the node position.

  The lateral vibration transmission unit 42 is formed in a substantially annular shape (short cylindrical shape including the vertical vibration transmission unit 40), and radially outward from the lower end side of the vertical vibration transmission unit 40 as described above. Overhangs. The lateral vibration transmission unit 42 is configured to reduce the vibration direction by the Poisson effect that tries to keep the volume constant as it expands and contracts in the axial direction due to the longitudinal vibration propagating to the integrally formed longitudinal vibration transmission unit 40. In the direction (along the plane perpendicular to the axial direction). The lateral vibration transmitting portion 42 has an outer peripheral surface formed as a cylindrical surface thereof as a support surface 42A, and forms a radiation surface that transmits ultrasonic lateral vibration Vr (see FIG. 2) propagating in the radial direction to the air. ing.

  In the horn 20, the distance from the axial center to the support surface 42 </ b> A (the radius of the lateral vibration transmitting portion 42) is approximately ¼ of the wavelength λ of the ultrasonic longitudinal vibration Vl described above. Since the lateral vibration transmitting portion 42 protrudes from the node position of the ultrasonic longitudinal vibration Vl in the longitudinal vibration transmitting portion 40, the support surface 42A has the ultrasonic lateral vibration Vr (the ultrasonic longitudinal vibration Vl and the wavelength λ substantially coincide with each other). (Radial vibration) to be the antinode position (position where the radial amplitude is maximized).

  Further, the lower end surface 42 </ b> B of the lateral vibration transmission unit 42 is positioned below the lower end surface 40 </ b> A of the vertical vibration transmission unit 40. That is, the support surfaces 42A of the lateral vibration transmission unit 42 are positioned on both upper and lower sides with respect to the lower end surface 40A, which is a node position of the ultrasonic longitudinal vibration Vl in the longitudinal vibration transmission unit 40, in the axial direction of the longitudinal vibration transmission unit 40. The vertical width W is as follows. With this shape, the transverse vibration transmitting portion 42 has the piezo element 16 (at least a part in the axial direction thereof) inserted inside the lower portion 42C in the radial direction.

  In this embodiment, the horn 20 described above is in direct contact with one of the piezo elements 16 and also functions as an electrode. Therefore, the horn 20 is electrically connected to the metal block 18 (the electrode in contact with) via the bolt 22. It is made of a conductive metal material (for example, an aluminum alloy such as JIS A2017P). When a material other than a metal material is used as the constituent material of the horn 20, a light and rigid material that does not attenuate ultrasonic vibration is desirable. When a non-conductive material is used, the horn 20 and the piezoelectric element 16 The electrode is also sandwiched between them. The length from the contact end surface of the electrode with the piezo element 16 to the upper end surface 40B is designed to be λ / 4. That is, in this configuration, the horn 20 including the electrode is grasped as the third member.

  On the other hand, the rotating levitating body 12 as a supported body is formed in a bottomed cylindrical shape that opens downward. Specifically, the rotating levitated body 12 is mainly composed of a cylindrical portion 46 having an inner diameter slightly larger than the outer diameter of the lateral vibration transmitting portion 42 and a table portion 48 that closes the upper portion of the cylindrical portion 46. ing. The rotary levitation body 12 is placed on the horn 20 so as to accommodate the horn 20 therein. In the squeeze air bearing 10, ultrasonic vibration is generated in the piezo element 16, so that the space between the lower surface 48 </ b> A of the table portion 48 and the upper end surface 40 </ b> B of the longitudinal vibration transmitting portion 40 and the inner peripheral surface 46 </ b> A of the cylindrical portion 46. And a support surface 42 </ b> A of the lateral vibration transmission unit 42, a squeezed air film is generated, and the rotary levitation body 12 is supported in a non-contact manner with respect to the horn 20, that is, the machine base 14.

  Thereby, in the squeeze air bearing 10, the supporting force based on the pressure of the squeeze air film generated between the lower surface 48 </ b> A of the table portion 48 and the upper end surface 40 </ b> B of the longitudinal vibration transmitting portion 40 acts on the rotating levitated body 12. The rotating levitated body 12 is supported in the thrust direction with respect to the machine base 14 by the balance with gravity. Further, in the squeeze air bearing 10, the rotating levitated body 12 is placed on the machine base 14 due to the pressure balance of the squeeze air film generated between the inner peripheral surface 46 A of the cylindrical portion 46 and the support surface 42 A of the lateral vibration transmitting portion 42. On the other hand, it is supported in the radial direction. Therefore, the squeeze air bearing 10 is configured to allow only rotation around its own axis by restricting 5 degrees of freedom among the 6 degrees of freedom of the rotary levitating body 12 with respect to the machine base 14.

  The rotary levitating body 12 is connected to a rotation driving means constituting an apparatus to which the squeeze air bearing 10 is applied, and is driven to rotate around its own axis, for example, a workpiece or sample placed on the table unit 48 with high accuracy. Rotate with.

  Since the oscillation frequency of the power supply circuit composed of the transmitter 26, the amplifier 28, and the converter 30 is normally adjusted somewhat, the excitation wavelength is naturally a value having a width, Further, since the piezo element 16, the metal block 18, and the horn 20 also generate heat and expand due to the ambient temperature and long time driving, the axial length of the longitudinal vibration transmission unit 40, the diameter of the lateral vibration transmission unit 42, etc. The dimensions are not strictly determined in one point. Design from the frequency scheduled for the most frequent operation, etc., and then try to confirm the dimensions that can truly obtain the maximum amplitude, etc., before final production. Is desirable. In that sense, the dimension based on the wavelength λ is assumed to be “designed” so as to be the target dimension, or “abbreviation” is added to indicate that the dimension has a certain width. It expresses.

  Next, the operation of the first embodiment will be described.

  In the squeeze air bearing 10 having the above-described configuration, when an alternating voltage is applied to the piezo element 16, the piezo element 16 generates ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage. This ultrasonic vibration is input to the horn 20 from the lower end surface 40A of the longitudinal vibration transmission unit 40, propagates in the longitudinal vibration transmission unit 40 in the axial direction, and the vibration direction is converted by 90 ° by the Poisson effect of the lateral vibration transmission unit 42. As a result, the transverse vibration transmitting portion 42 propagates in the radial direction. The ultrasonic longitudinal vibration Vl propagated through the longitudinal vibration transmitting unit 40 generates ultrasonic vibrations on the upper end surface 40B of the longitudinal vibration transmitting unit 40 to generate a squeeze air film between the table 48 of the rotating levitated body 12. The Vr propagated through the lateral vibration transmission unit 42 generates ultrasonic vibrations on the support surface 42 </ b> A and generates a squeeze air film between the rotating floating body 12 and the cylindrical portion 46.

  As a result, the rotating levitated body 12 is non-contacting (floating) with respect to the horn 20, that is, the machine base 14 in both the thrust direction and the radial direction, and is supported rotatably around its own axis, and the remaining five degrees of freedom are constrained. Is done. Since the squeeze air bearing 10 has a simple cylindrical surface or flat surface as a squeeze air film forming surface, the processing accuracy of the components is increased to increase the film thickness of the squeeze air film, that is, the horn 20 and the rotating levitated body 12. Can be set small. For this reason, in the squeeze air bearing 10, high support rigidity can be obtained. In the squeeze air bearing 10, a squeeze air film is applied to each part (the entire circumference of the upper end surface 40 </ b> B and the support surface 42 </ b> A) in a configuration in which ultrasonic vibration is input only to the lower end surface 40 </ b> A that is one end surface of the longitudinal vibration transmission unit 40. The configuration to be generated is realized. Further, since the piezo element 16 and the horn 20 are provided on the machine base 14 side with respect to the rotary levitation body 12, compared to the configuration in which the piezo element 16 and the horn 20 are provided on the rotary levitation body 12, the supported side It is possible to suppress the occurrence of residual vibration.

  Here, in the squeeze air bearing 10, since the ultrasonic vibration generated by the piezo element 16 is directly input to the lower end surface 40A of the longitudinal vibration transmitting portion 40 of the horn 20, the axial dimension is greatly reduced. . In the squeeze air bearing 10, the length along the axial direction from the lower end surface 40 </ b> A to the upper end surface 40 </ b> B of the longitudinal vibration transmission unit 40 is the wavelength λ of ultrasonic vibration propagating in the longitudinal vibration transmission unit 40 in the axial direction. Therefore, the upper end surface 40B can be made to substantially coincide with the antinode position of the ultrasonic vibration, and the lower end surface 40A can be made to substantially coincide with the node position of the ultrasonic vibration. Thereby, the shortest configuration in the axial direction for maximizing the amplitude of the ultrasonic vibration of the upper end face 40B was realized. Moreover, the horn 20 to which the ultrasonic vibration from the piezo element 16 is directly inputted has little loss (attenuation etc.) of the ultrasonic vibration, and the ultrasonic vibration is efficiently propagated to the upper end surface 40B and the support surface 42A. can do.

  Further, in the squeeze air bearing 10, the support surface 42 </ b> A that is the ultrasonic radiation surface in the radial direction of the horn 20 is the outer peripheral surface of the lateral vibration transmitting portion 42 projecting in the radial direction, and thus propagates in the radial direction due to the Poisson effect. The ultrasonic vibration to be received is not subject to interference with other portions, and the amplitude at the support surface 42A can be increased. In particular, the lateral vibration transmitting portion 42 extending radially outward from the lower end surface 40A, which is the above-described node position in the longitudinal vibration transmitting portion 40, transmits ultrasonic vibration from the node position. The amplitude is likely to increase, and the length from the axial center of the longitudinal vibration transmitting portion 40 to the support surface 42A, that is, the radius of the lateral vibration transmitting portion 42 is set to λ / 4. A configuration has been realized in which the amplitude of is maximized (close to the theoretical maximum). Further, the support surface 42A has a configuration in which the lower end surface 40A that is the above-described node position in the longitudinal vibration transmission unit 40 is included in the range of the vertical (along the axial direction) width thereof, in other words, the longitudinal vibration transmission. Since the support surfaces 42A are located on both sides in the axial direction with respect to the lower end surface 40A of the portion 40, an area of a portion having a large radial amplitude is secured.

  Further, here, in the squeeze air bearing 10, the flange 36 provided on the metal block 18 is supported by the machine base 14 via a plurality of support columns 38. In other words, the horn 20 is in an unconstrained state with respect to the machine base 14. Therefore, the ultrasonic vibration from the piezo element 16 is efficiently propagated to the upper end surface 40B and the support surface 42A (in this embodiment, particularly the support surface 42A). In particular, the metal block 18 is fixed to the machine base 14 with a flange 36 extending along the upper end surface 32A of the block main body 32. In other words, the contact surface with the piezo element 16, that is, ultrasonic longitudinal vibration. Since it is supported with respect to the machine base 14 in the very vicinity of the node position of Vl (see FIG. 2), the ultrasonic vibration is prevented from being transmitted to the outside of the machine via the machine base 14.

  As described above, in the squeeze air bearing 10, the apparatus can be downsized, and the loss due to attenuation of the ultrasonic vibration is small, so that the energy efficiency is high and the support rigidity is high. About these points, it supplements, comparing with the squeeze air bearing 200 which concerns on the comparative example shown in FIG.

  First, the squeeze air bearing 200 shown in FIG. 11 will be described. The squeeze air bearing 200 is a so-called bolted Langevin type ultrasonic vibrator 204 configured by sandwiching the piezoelectric element 16 and an electrode between a pair of upper and lower metal blocks 202. And a horn 206 joined to the end surface of one metal block 202. In the horn 206, the length of the longitudinal vibration transmission unit 208 is set to be approximately ½ of the wavelength λ of the ultrasonic vibration propagating in the axial direction through the longitudinal vibration transmission unit 208. The end surfaces 208A and 208B of the ultrasonic waves produce the antinodes of the ultrasonic longitudinal vibration Vl, and the nodes of the ultrasonic longitudinal vibration Vl are produced at the center in the vertical direction. The upper end surface 208 </ b> B of the longitudinal vibration transmitting unit 208 generates a squeeze air film between the table unit 48 and ultrasonic vibration. A lateral vibration transmitting portion 210 extends radially outward from the vertical center of the longitudinal vibration transmitting portion 208 (node position of the ultrasonic longitudinal vibration Vl). A certain outer peripheral surface serves as a support surface 210 </ b> A that generates a squeezed air film with the cylindrical portion 46 by ultrasonic vibration. The diameter of the lateral vibration transmission unit 210 is approximately ½ of the wavelength λ. An inner peripheral side portion of the lateral vibration transmission unit 210 is fixedly supported on the machine base 14 via a plurality of support columns 38. The upper portions of the plurality of support columns 38 are inserted into holes 210B provided in the lateral vibration transmission unit 210, and the upper ends 38A are fixed to the hole bottom wall 210C by screws, for example.

  By the way, in this squeeze air bearing 200, an ultrasonic vibrator 204 having a pair of metal blocks 202 and a horn 206 having a longitudinal vibration transmitting portion 208 having an axial length of approximately λ / 2 are connected in series in the axial direction. Since it is configured by joining, the total length is equivalent to approximately one wavelength of ultrasonic vibration propagating in the axial direction through the longitudinal vibration transmitting portion 208. On the other hand, in the squeeze air bearing 10, since the piezo element 16 is sandwiched between the horn 20 and the metal block 18, the horn 20 is shortened by setting the axial length of the longitudinal vibration transmitting portion 40 to approximately λ / 4, Parts corresponding to the metal block 202 are not required, and the axial length of the metal block 18 can be made λ / 4 or less, so that the axial length is about λ / 2 as compared with the squeeze air bearing 200. Was able to be shortened. In comparison of prototypes using the same piezo element 16, the squeeze air bearing 200 has a length L2≈116 mm from the lower end of the piezo element 16 on the lower side of the ultrasonic transducer 204 to the upper end surface 208B of the longitudinal vibration transmitting portion 208. In contrast, in the squeeze air bearing 10, the length L from the lower end of the lower piezo element 16 to the upper end surface 40B of the longitudinal vibration transmitting portion 40 is approximately 57 mm, which is reduced to approximately 49%. In these prototypes, the outer diameters (corresponding to λ / 2) of the lateral vibration transmitting portions 42 and 210 were unified to 70 mm.

  Further, in the squeeze air bearing 200, there is a concern that the joint between the metal block 202 and the horn 206 hinders transmission of ultrasonic vibration. Further, in the squeeze air bearing 200, the lateral vibration transmission unit 210 is fixed to the machine base 14 via the plurality of support columns 38. In other words, the node position of the ultrasonic vibration (the longitudinal vibration transmission unit 208 in the radial direction). Since the part that generates the vibration separated from the axial center part of the machine part 14 is a support part for the machine base 14, there is a concern that the vibration propagation in the radial direction is hindered. FIG. 3B shows the experimental results using the prototype squeeze air bearing 200 described above. This figure shows the amplitude response of the upper end surface 208B and the support surface 210A of the horn 206 with respect to the excitation frequency. In addition, the gap sensor (The optical fiber type displacement meter D63H by Philtec, frequency characteristics: DC-50kHz) was used for the amplitude measurement of each part. From FIG. 3B, the axial and radial resonance frequencies in the prototype of the squeeze air bearing 200 are approximately 43.3 Hz, and the maximum axial amplitude at the upper end surface 208B (both amplitudes, the same applies hereinafter). It was found that the maximum amplitude in the radial direction on the support surface 210A was approximately 1.22 μm.

  On the other hand, FIG. 3 (A) shows an experimental result under the same conditions for a prototype of the squeeze air bearing 10. From FIG. 3A, the axial and radial resonance frequencies in the prototype of the squeeze air bearing 10 are approximately 45.3 Hz, and the maximum amplitude (both amplitudes, hereinafter the same) of the upper end surface 40B is 1. It can be seen that the maximum amplitude of the support surface 42A was about 1.83 μm.

  In the squeeze air bearing 10, the maximum axial amplitude is improved (substantially increased by 3%) compared to the squeeze air bearing 200 because the piezo element 16 is sandwiched between the horn 20 and the metal block 18. This is mainly due to the loss of vibration transmission caused by the joint between the vibrator 204 and the horn 206. In the squeeze air bearing 10, the ratio of the maximum radial amplitude to the maximum axial amplitude (approximately 93%) is the ratio of the maximum radial amplitude to the maximum axial amplitude in the squeeze air bearing 200 (approximately 64%). The horn 20 is not directly restrained with respect to the machine base 14 but is fixed to the machine base 14 via the metal block 18 so that the lateral vibration transmission unit 210 is mounted on the machine base. This is mainly due to the elimination of the factor for inhibiting the vibration transmission in the radial direction, which has been caused by fixing to 14.

  In the squeeze air bearing 10, the radial maximum amplitude in the radial direction is increased (approximately 150%) as compared with the squeeze air bearing 200, thereby improving the radial support rigidity of the rotating levitated body 12. . Specifically, the radial support rigidity of the squeeze air bearing 200 prototype was 1.18 N / μm, and the squeeze air bearing 10 prototype is 2.11 N / μm, which is smaller than that of the squeeze air bearing 200. The rigidity was improved by about 79%.

  As described above, in the squeeze air bearing 10 according to the first embodiment of the present invention, as compared with the squeeze air bearing 200 according to the comparative example, it is realized that the size reduction is achieved while improving the performance. Further, the squeeze air bearing 10 can be further downsized by increasing the excitation frequency and shortening the wavelength λ.

  Next, another embodiment of the present invention will be described. Note that parts / parts that are basically the same as those in the first embodiment or the previous configuration are denoted by the same reference numerals as those in the first embodiment or the previous configuration, and description thereof is omitted. Illustration may be omitted.

(Second Embodiment)
FIG. 4 is a sectional view showing a squeeze air bearing 50 according to the second embodiment. As shown in this figure, in the squeeze air bearing 50, a horn 52 is replaced with a lateral vibration transmission portion 42 having a support surface 42A which is a cylindrical surface, and a lateral vibration transmission portion 54 having tapered support surfaces 54A and 54B. This is different from the squeeze air bearing 10 according to the first embodiment. This will be specifically described below.

  The lateral vibration transmission portion 54 extends from the lower end portion of the longitudinal vibration transmission portion 40 over the entire circumference in the radial direction, and the upper portion 54C of the upper portion 54C located above the lower end surface 40A of the longitudinal vibration transmission portion 40 is extended. The outer peripheral surface is an upward support surface 54A facing both the radially outer side and the upper side, and the outer peripheral surface of the lower portion 54D located below the lower end surface 40A of the lower end surface 40A of the longitudinal vibration transmitting portion 40 is the radial direction. It is set as the downward support surface 54B which faces both the outer side and the lower side. In this embodiment, the upward support surface 54A and the downward support surface 54B each have an average distance (radius) from the axial center of the longitudinal vibration transmitting portion 40 of λ / 4.

  On the other hand, the rotating levitated body 12 has a cylindrical portion 56 instead of the cylindrical portion 46. The downward opening end of the cylindrical portion 56 has a chamfered shape, and is a tapered surface 56A that faces the upward support surface 54A and can generate a squeeze air film between the upward support surface 54A. A ring member 58 is coaxially joined to the open end of the cylindrical portion 56. An inner edge shape of the ring member 58 is a tapered surface 58A that can face the downward support surface 54B and generate a squeeze air film between the downward support surface 54B.

  Other configurations of the squeeze air bearing 50 are the same as the corresponding configurations of the squeeze air bearing 10 including a portion not shown. Therefore, the squeeze air bearing 50 has the same effects as the squeeze air bearing 10 according to the first embodiment in terms of downsizing and improvement in support rigidity (increase in amplitude on the upward support surface 54A and the downward support surface 54B). is there.

  In the squeeze air bearing 50 having the above-described configuration, when an alternating voltage is applied to the piezo element 16, the piezo element 16 generates ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage. This ultrasonic vibration is input to the horn 20 from the lower end surface 40A of the longitudinal vibration transmission unit 40, propagates in the longitudinal vibration transmission unit 40 in the axial direction, and the vibration direction is converted by 90 ° by the Poisson effect of the lateral vibration transmission unit 54. Thus, the lateral vibration transmitting portion 54 propagates in the radial direction. The ultrasonic longitudinal vibration Vl propagated through the longitudinal vibration transmitting unit 40 generates ultrasonic vibrations on the upper end surface 40B of the longitudinal vibration transmitting unit 40 to generate a squeeze air film between the table 48 of the rotating levitated body 12. The ultrasonic transverse vibration Vr propagated through the transverse vibration transmitting portion 54 causes ultrasonic vibrations on the upward support surface 54A and the downward support surface 54B, and squeezed air between the taper surfaces 56A and 58A of the rotating levitated body 12. Create a film.

  As a result, the rotating levitated body 12 is non-contacting (floating) with respect to the horn 20, that is, the machine base 14 in both the thrust direction and the radial direction, and is supported rotatably around its own axis, and the remaining five degrees of freedom are constrained. Is done. In particular, in the squeeze air bearing 50, the rotary levitation body 12 has a downward displacement (degree of freedom) generated between the upper end surface 40B and a squeeze air film between the upward support surface 54A and the tapered surface 56A. The upward displacement is restrained by the squeeze air film generated between the downward support surface 54B and the tapered surface 58A. That is, in the squeeze air bearing 50, the thrust in the thrust direction (upper side) of the rotating levitated body 12 is also formed by the squeeze air film.

(Third embodiment)
FIG. 5 is a sectional view showing a squeeze air bearing 60 according to the third embodiment. As shown in this figure, in the squeeze air bearing 60, the horn 62 is tapered to the lower side of the support surface 64A which is a cylindrical surface, instead of the lateral vibration transmitting portion 42 having the support surface 42A constituted only by the cylindrical surface. The squeeze air bearing 10 according to the first embodiment is different from the squeeze air bearing 10 according to the first embodiment in that it has a lateral vibration transmitting portion 64 having a support surface 64B. This will be specifically described below.

  The lateral vibration transmitting portion 64 extends from the lower end portion of the longitudinal vibration transmitting portion 40 over the entire circumference in the radial direction, and the portion other than the lower portion on the outer peripheral surface is the axis of the longitudinal vibration transmitting portion 40. 64A is a support surface 64A having a distance (radius) from λ / 4. The lower portion of the support surface 64A on the outer peripheral surface of the lateral vibration transmitting portion 64 is a tapered support surface 64B that faces both the radially outer side and the lower side.

  On the other hand, the rotating levitated body 12 generates a squeezed air film between the inner peripheral surface 46A near the lower end of the cylindrical portion 46 and the support surface 64A. The ring member 66 is joined coaxially. An inner edge shape of the ring member 66 is a tapered surface 66A that faces the tapered support surface 64B and can generate a squeeze air film between the tapered support surface 64B.

  Other configurations of the squeeze air bearing 60 are the same as the corresponding configurations of the squeeze air bearing 10 including a portion not shown. Therefore, in the squeeze air bearing 60, the effects related to the downsizing and the improvement of the support rigidity (increase in amplitude at the support surface 64A and the tapered support surface 64B) are the same as those of the squeeze air bearing 10 according to the first embodiment. It is.

  In the squeeze air bearing 60 having the above-described configuration, when an alternating voltage is applied to the piezo element 16, the piezo element 16 generates ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage. This ultrasonic vibration is input to the horn 20 from the lower end surface 40A of the longitudinal vibration transmission unit 40, propagates in the longitudinal vibration transmission unit 40 in the axial direction, and the vibration direction is converted by 90 ° by the Poisson effect of the lateral vibration transmission unit 64. As a result, the lateral vibration transmitting portion 64 propagates in the radial direction. The ultrasonic longitudinal vibration Vl propagated through the longitudinal vibration transmitting unit 40 generates ultrasonic vibrations on the upper end surface 40B of the longitudinal vibration transmitting unit 40 to generate a squeeze air film between the table 48 of the rotating levitated body 12. The ultrasonic transverse vibration Vr propagated through the transverse vibration transmitting portion 64 generates ultrasonic vibrations on the support surfaces 64A and 64B, and the inner peripheral surface 46A of the cylindrical portion 46 of the rotating levitated body 12 and the tapered surface 66A of the ring member 66. A squeeze air film is generated between each of the two.

  As a result, the rotating levitated body 12 is non-contacting (floating) with respect to the horn 20, that is, the machine base 14 in both the thrust direction and the radial direction, and is supported rotatably around its own axis, and the remaining five degrees of freedom are constrained. Is done. In particular, in the squeeze air bearing 60, the rotary levitation body 12 has a downward displacement (degree of freedom) constrained by a squeeze air film generated between the upper end surface 40B and the upward displacement is a tapered support surface 64B. Is constrained by a squeeze air film generated between the taper surface 66A and the tapered surface 66A. That is, in the squeeze air bearing 60, the thrust levitation body 12 in the thrust direction (upper side) is also formed by the squeeze air film.

(Fourth embodiment)
FIG. 6A shows a squeeze air linear guide 70 as a non-contact support according to the fourth embodiment in a cross-sectional view, and FIG. 6B shows the squeeze air linear guide 70. It is shown in a longitudinal section. As shown in these drawings, the squeeze air linear guide 70 rotates in that the slider 72 as a second member or a supported body is supported so as to be displaceable in the axial direction with respect to the machine base 14 in a non-contact manner. This is different from the squeeze air bearings 10, 50, 60 that support the floating body 12 rotatably with respect to the machine base 14.

  The squeeze air linear guide 70 includes a horn 74. The horn 74 includes a longitudinal vibration transmission unit 76 that is disposed with its axial direction substantially aligned with the horizontal direction. The longitudinal vibration transmitting unit 76 sandwiches the piezo element 16 and the electrode between the axial end surfaces 76 </ b> A and the metal block 18. The length in the axial direction of the longitudinal vibration transmission unit 76 is approximately ½ of the wavelength λ of ultrasonic vibration propagating through the longitudinal vibration transmission unit 76 (twice as long as λ / 4). As a result, the longitudinal vibration transmission unit 76 has a configuration in which the central portion in the axial direction becomes the antinode position of the ultrasonic vibration, and each end surface 76A in the axial direction becomes the node position of the ultrasonic vibration (FIG. 6A). Sonic longitudinal vibration Vl).

  The horn 74 has a lateral vibration transmitting portion 78 as a projecting portion projecting in the radial direction from the position of the ultrasonic vibration in the longitudinal vibration transmitting portion 76, that is, from both axial end portions. As shown in FIGS. 6B and 7, the lateral vibration transmitting portion 78 is formed in a substantially square shape when viewed in the axial direction. An outer peripheral surface of the lateral vibration transmitting portion 78 is a support surface 78A. In this embodiment, the average distance from the axial center of the longitudinal vibration transmission unit 40 to the outer peripheral surface of the lateral vibration transmission unit 78 is approximately λ / 4. The lateral vibration transmission portion 78 of the horn 74 has a width located on both sides in the axial direction with respect to the axial end surfaces 76A, similarly to the lateral vibration transmission portion 42 in the first embodiment.

  In the squeeze air linear guide 70, the flange 36 of each metal block 18 arranged horizontally is supported by a bracket 82 via a support beam 80, and the bracket 82 is fixed to the machine base.

  The slider 72 is formed in a rectangular cylindrical shape, and is formed so as to face each surface of the support surface 78A with a predetermined interval. In this embodiment, as shown in FIG. 6B, the slider 72 spans between the upper ends of the pair of side wall members 84 by the top plate member 86 and also the bottom plate member 88 between the lower ends of the pair of side wall members 84. It is constructed over the bridge.

  In the squeezed air linear guide 70 configured as described above, when the piezoelectric elements 16 on both sides in the axial direction are driven in synchronization, ultrasonic vibration propagates in the longitudinal vibration transmitting portion 76 of the horn 74 in the axial direction, and both axial end surfaces 76A. Is the node position of this ultrasonic guidance. Each lateral vibration transmitting portion 78 of the horn 74 transforms the propagation direction of the ultrasonic vibration by 90 ° by the Poisson effect along with the deformation due to the ultrasonic vibration, and generates the ultrasonic vibration on the support surface 78A. Then, a squeeze air film is generated between the support surface 78A and the inner surface of the slider 72 (the pair of side wall members 84, the top plate member 86, and the bottom plate member 88), and the slider 72 is not in contact with the machine base 14. Axial movement is allowed and the remaining five degrees of freedom are constrained.

  Here, in the squeezed air linear guide 70, since the ultrasonic vibration generated by the piezo element 16 is directly input to both axial end surfaces 76A of the horn 74, the dimension in the axial direction is greatly reduced. In the squeezed air linear guide 70, the length along the axial direction of the longitudinal vibration transmitting portion 76 is approximately ½ of the wavelength λ of the ultrasonic vibration propagating through the longitudinal vibration transmitting portion 76 in the axial direction. Thus, a configuration in which there are two nodes of ultrasonic vibration and the length is shortened to about one wavelength (equivalent to λ) was realized. As a result, the support surfaces 78A (lateral vibration transmitting portions 78) are provided at two locations spaced apart in the axial direction, and the slider 72 can be stably supported so as to be movable in the axial direction. Moreover, the horn 20 to which the ultrasonic vibration from the piezo element 16 is directly inputted has little loss (attenuation etc.) of the ultrasonic vibration, and the ultrasonic vibration is efficiently propagated to the upper end surface 40B and the support surface 42A. can do.

  Further, in the squeeze air linear guide 70, the support surface 78A, which is the radial ultrasonic radiation surface of the horn 74, is the outer peripheral surface of the lateral vibration transmitting portion 78 projecting in the radial direction. The propagating ultrasonic vibration does not receive interference with other portions (portions between the two lateral vibration transmitting portions 78), and the amplitude at the support surface 78A can be increased. In particular, each lateral vibration transmitting portion 78 extending radially outward from each axial end surface 76A, which is the above-described node position in the longitudinal vibration transmitting portion 76, transmits ultrasonic vibration from the node position, and thus the support surface 78A. In addition, since the average length from the axial center of the longitudinal vibration transmitting portion 76 to 78A is set to about λ / 4, the radial amplitude on the support surface 78A is almost the same. A maximized configuration (close to the theoretical maximum) was realized. Further, since the support surface 78A is configured to include the end surface 76A that is the above-described node position in the longitudinal vibration transmitting portion 78 in the range of the width along the axial direction, an area of a portion having a large radial amplitude is secured. Has been.

  Here, in the squeeze air linear guide 70, the flange 36 provided on the metal block 18 is supported by the machine base 14 via a plurality of support beams 80 and brackets 82. In other words, the horn 74 is mounted on the machine base. 14 receives vibration from 16 in an unconstrained state with respect to 14, so that the ultrasonic vibration from the piezo element 16 is efficiently propagated to the support surface 78A. In particular, since the metal block 18 is fixed to the machine base 14 with a flange 36 extending along the upper end surface 32A of the block main body 32, the ultrasonic vibration is transmitted to the outside of the machine via the machine base 14. It is prevented.

  As described above, in the squeeze air linear guide 70, the apparatus can be downsized, and the loss due to attenuation of the ultrasonic vibration is small, so that the energy efficiency is high and the support rigidity is high. These points will be supplemented while comparing with the squeeze air linear guide 300 according to the comparative example shown in FIGS. 12 (A) and 12 (B).

  First, the squeeze air linear guide 300 shown in FIG. 12 will be described. The squeeze air linear guide 300 includes horns 302 in which two bolted Langevin type ultrasonic transducers 204 are joined to both ends in the axial direction. In the horn 302, the length of the longitudinal vibration transmitting portion 304 is equal to the wavelength λ of ultrasonic vibration propagating through the longitudinal vibration transmitting portion 304 in the axial direction, and the longitudinal vibration transmitting portion 304 has both end surfaces in the axial direction. An antinode of ultrasonic vibration is generated at 304A and the central portion, and a node of ultrasonic vibration is generated at a position where the axial distance from both axial end faces 304A is approximately λ / 4. A lateral vibration transmitting portion 306 formed in a substantially square shape in the axial direction is extended radially outward from an axial position portion where the vibration node in the longitudinal vibration transmitting portion 304 is generated. The outer peripheral surface of the transmission portion 306 is a support surface 306A that generates a squeezed air film between the slider 72 and the slider 72 by ultrasonic vibration. The average distance from the axial center of the longitudinal vibration transmitting unit 304 to the support surface 306A is approximately ¼ of the wavelength λ. Further, the lateral vibration transmission unit 210 is fixedly supported on the machine base 14 via a plurality of support beams 80 and a bracket 82. Each of the plurality of support beams 80 is inserted into a hole 306B provided in part 306, and the free end 80A is fixed to the hole bottom wall 306C by, for example, screwing. Therefore, also in the squeeze air linear guide 300 according to the comparative example, the slider 72 can be supported in a non-contact manner so as to be axially displaceable (slidable) with respect to the machine base 14 and to constrain the remaining five degrees of freedom. .

  By the way, this squeezed air linear guide 300 is configured by joining a pair of ultrasonic transducers 204 and a horn 302 having a longitudinal vibration transmission portion 304 having an axial length of λ in series in the axial direction. Therefore, the total length is approximately two wavelengths of ultrasonic vibrations propagating in the axial direction through the longitudinal vibration transmitting unit 304. On the other hand, in the squeeze air linear guide 70, since the piezo element 16 is sandwiched between the horn 74 and the metal block 18, the length of the longitudinal vibration transmitting portion 76 in the axial direction is set to λ / 2, and the horn 74 is shortened. A part corresponding to the metal block 202 on the joint side with the transmission unit 304 is not required, and the length of the metal block 18 in the axial direction can be λ / 4 or less. The direction length could be greatly reduced.

  Further, in the squeeze air linear guide 70, there is no vibration transmission hindrance corresponding to the joint between the ultrasonic transducer 204 and the longitudinal vibration transmission unit 304, so that ultrasonic vibration is efficiently transmitted from the piezo element 16 to the horn 74. Is done. In the squeeze air linear guide 70 supported by the machine base 14 in the metal block 18, the lateral vibration transmission unit 78, that is, the horn 74 receives vibration from the piezo element 16 in an unconstrained state with respect to the machine base 14. Unlike the squeeze air linear guide 300 supported by the machine base 14 in the part 306, the propagation of radial vibration is not hindered, and the radial amplitude of the support surface 78A is compared with the radial amplitude of the support surface 306A. Can be significantly increased. Thereby, in the squeeze air linear guide 70, the support rigidity of the slider 72 is improved as compared with the squeeze air linear guide 300.

  As described above, the squeeze air linear guide 70 according to the fourth embodiment of the present invention achieves downsizing while improving performance as compared with the squeeze air linear guide 300 according to the comparative example. It was. Further, the squeezed air linear guide 70 can be further downsized by increasing the excitation frequency and shortening the wavelength λ.

(Fifth embodiment)
FIG. 8 is a sectional view showing a squeeze air linear guide 90 according to the fifth embodiment. As shown in this figure, the squeeze air linear guide 90 is the fourth embodiment in that a slider 92 as a supported body is shorter in the axial direction than the slider 72 and the horn 94 has one lateral vibration transmitting portion 78. It differs from the squeeze air linear guide 70 which concerns on a form. This will be specifically described below.

  The length of the slider 92 in the axial direction is substantially half that of the slider 72 in the axial direction. The horn 94 is configured such that a lateral vibration transmitting portion 78 extends in the radial direction from one end face 40A of the longitudinal vibration transmitting portion 40 whose axial direction is aligned with the horizontal direction. In the horn 94, a part of one end side in the axial direction of the lateral vibration transmitting portion 78 covers the piezo element 16 from the outer peripheral side so that the one end face 40A is positioned within the width of the lateral vibration transmitting portion 78 in the axial direction. Yes. Other configurations of the squeeze air linear guide 90 are the same as the corresponding configurations of the squeeze air linear guide 70.

  Therefore, the squeeze air linear guide 90 can basically obtain the same effect by the same operation as that of the squeeze air linear guide 70. Supplementing the squeeze air linear guide 90, in the squeeze air linear guide 90, the longitudinal length of the longitudinal vibration transmitting portion 40 of the horn 94 is approximately λ / 4, and only one end face 40A in the axial direction is added from the piezo element 16. Since the structure is vibrated, the total length of the lower portion in series of the metal block 18, the piezo element 16, and the horn 94 in the axial direction can be made substantially λ / 2. The squeeze air linear guide 90 is suitable for handling a small work or sample as compared with the squeeze air linear guide 70.

(Sixth embodiment)
FIG. 9 is a sectional view showing a squeeze air guide 100 according to the sixth embodiment. As shown in this figure, the squeeze air guide 100 supports a floating body 102 as a supported body so that it can rotate around its own axis and be displaced (slidable) in the axial direction, and restrains the remaining four degrees of freedom. The squeeze air bearing 10 according to the first embodiment is different from the squeeze air linear guide 90 according to the fifth embodiment.

  The squeeze air guide 100 is configured in the same manner as the squeeze air bearing 10 except that the squeeze air guide 10 includes a levitation body 102 instead of the rotation levitation body 12, and the levitation body 102 is similar to the cylindrical portion 46 of the rotation levitation body 12, that is, The table portion 48 for generating a squeezed air film for supporting in the thrust direction is provided between the upper end surface 40B and the upper end surface 40B. As a result, the levitated body 102 is allowed to rotate about its own axis and to be displaced in the axial direction.

  In this squeeze air guide 100, the operational effects relating to downsizing and improvement in support rigidity (increase in amplitude on the support surface 42A) are the same as those in the squeeze air bearing 10 according to the first embodiment. Note that the squeeze air guide 100 may be disposed by fixing the metal block 18 to the machine base 14 via the support beam 80 and the bracket 82 so that the axial direction of the horn 20 coincides with the horizontal direction.

(Seventh embodiment)
FIG. 10 is a sectional view showing a squeeze air spherical joint 110 according to the seventh embodiment. As shown in this figure, the squeeze air spherical joint 110 supports a levitated body 112 as a supported body so as to be capable of spherical movement (rotation with three degrees of freedom) around its own axis, and restrains the remaining three degrees of freedom. This is different from the squeeze air bearing 10 according to the first embodiment in that the horn 114 is provided.

  The floating body 112 has a spherical surface at least on its inner surface, and in this embodiment, is formed in a substantially hemispherical shell shape. In the horn 114, the longitudinal vibration transmission unit 116 sandwiches the piezo element 16 and the electrode between the lower end surface 116 </ b> A and the metal block 18. The upper end surface of the longitudinal vibration transmitting unit 116 is a support surface 116 </ b> B formed on a spherical surface corresponding to the inner surface of the levitated body 112. In addition, the horn 114 includes a lateral vibration transmission unit 118 that extends in the radial direction from the lower end of the longitudinal vibration transmission unit 116. The outer peripheral surface of the lateral vibration transmitting unit 118 is a support surface 118 </ b> A that is a spherical surface corresponding to the inner surface of the levitated body 112. In this embodiment, the support surfaces 116 </ b> B and 118 </ b> A are spherical surfaces that are concentric with each other about the axis of the lower end surface 40 </ b> A of the longitudinal vibration transmission unit 40. In the horn 114, the average distance from the lower end surface 116A of the longitudinal vibration transmitting portion 116 to the support surface 116B is λ / 4, and the average diameter of the lateral vibration transmitting portion 118 is λ / 2.

  Other configurations of the squeeze air spherical joint 110 are the same as the corresponding configurations of the squeeze air bearing 10. Therefore, in this squeeze air spherical joint 110, the effect of downsizing and improvement in support rigidity (increase in amplitude at the support surface 118A) is the same as that of the squeeze air bearing 10 according to the first embodiment.

  In the squeeze air spherical joint 110 having the above-described configuration, when an alternating voltage is applied to the piezo element 16, the piezo element 16 generates ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage. This ultrasonic vibration is input to the horn 20 from the lower end surface 116A of the longitudinal vibration transmission unit 116, propagates in the longitudinal vibration transmission unit 116 in the axial direction, and the vibration direction is converted by 90 ° by the Poisson effect of the lateral vibration transmission unit 118. As a result, the transverse vibration transmitting portion 118 propagates in the radial direction. The ultrasonic vibration propagated through the longitudinal vibration transmission unit 116 generates ultrasonic vibration on the support surface 116B of the longitudinal vibration transmission unit 116 to generate a squeeze air film between the inner surface of the levitated body 112 and the lateral vibration transmission unit. The ultrasonic vibration propagated through 54 generates ultrasonic vibration on the support surface 118 </ b> A and generates a squeezed air film between the inner surface of the levitated body 112. As a result, the levitated body 112 is supported in a non-contact (floating) manner with respect to the horn 114, that is, the machine base 14, so that the levitation body 112 can rotate with three degrees of freedom, that is, can move spherically, and the remaining three degrees of freedom are restricted.

  In each of the above-described embodiments, the horns constituting the squeeze air bearings 10, 50, 60, the squeeze air linear guides 70, 90, the squeeze air guide 100, and the squeeze air spherical joint 110 are arranged in the radial direction from the longitudinal vibration transmitting unit 40. Although the example which has the lateral vibration transmission part which protruded was shown, this invention is not limited to this, For example, it is good also as a support surface which ultrasonically vibrates the outer peripheral surface of a longitudinal vibration transmission part to radial direction. Therefore, the cross-sectional shape of the longitudinal vibration transmitting portion is not limited to a circular shape, and a shape corresponding to a use (degree of freedom allowing motion) can be taken.

  Further, in each of the above-described embodiments, a preferable example is shown in which the excitation surface of the piezo element 16 (the lower end surface 40A of the longitudinal vibration transmission unit 40, etc.) is positioned within the range in the width direction of the lateral vibration transmission unit 42 in the axial direction. However, the present invention is not limited to this, and for example, the lower surface 42B of the lateral vibration transmission unit 42 and the like may be formed flush with the excitation surface (the lower end surface 40A of the vertical vibration transmission unit 40) by the piezoelectric element 16. good.

  Furthermore, in each of the above-described embodiments, an example in which a piezo element is provided as a vibration generator has been described. However, the present invention is not limited to this, and various vibrations that can generate ultrasonic vibration (can oscillate a horn). The body can be employed.

  Furthermore, in each of the above-described embodiments, the example in which the piezo element 16 and the horn are provided on the machine base 14 side that supports the supported member in a non-contact manner is shown, but the present invention is not limited to this, and for example, An ultrasonic vibration source (vibrator, etc.) may be provided on the support side.

It is sectional drawing which shows the whole structure of the squeeze air bearing which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the dimension of the squeeze air bearing which concerns on the 1st Embodiment of this invention. (A) is a diagram which shows the experimental result of the output amplitude with respect to the drive frequency of the squeeze air bearing which concerns on the 1st Embodiment of this invention, (B) is the output amplitude with respect to the drive frequency of the squeeze air bearing which concerns on a comparative example. It is a diagram which shows the experimental result of. It is sectional drawing which shows the squeeze air bearing which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the squeeze air bearing which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the squeeze air linear guide which concerns on the 4th Embodiment of this invention. It is a perspective view of the horn which comprises the squeeze air linear guide which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the squeeze air linear guide which concerns on the 5th Embodiment of this invention. It is sectional drawing which shows the squeeze air guide 100 which concerns on the 6th Embodiment of this invention. It is sectional drawing which shows the squeeze air spherical joint 110 which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the squeeze air bearing which concerns on the comparative example with the 1st Embodiment of this invention. It is sectional drawing which shows the squeeze air linear guide which concerns on the comparative example with the 4th Embodiment of this invention.

Explanation of symbols

10 Squeeze air bearing (non-contact support device)
12 Rotating levitated body (second member)
14 Machines 16 Piezo elements (vibrators, piezoelectric elements)
18 Metal block (first member)
20 Horn (third member)
36 Flange 40 Longitudinal vibration transmission part (third member)
40A Lower end surface (one end surface of the third member)
40B Upper end surface (the other end surface of the third member)
42 Lateral vibration transmission part (overhang part)
42A Support surface 50 Squeeze air bearing (non-contact support device)
52 Horn (third member)
54 Lateral vibration transmission part (overhang part)
54A Upward support surface (support surface)
54B downward support surface (support surface)
60 Squeeze air bearing (non-contact support device)
62 Horn (third member)
64 Lateral vibration transmission part (overhang part)
64A Support surface 64B Support surface 70 Squeeze air linear guide (non-contact support device)
72 Slider (second member)
74 Horn (third member)
76 Longitudinal vibration transmission part (third member)
76A end face (one end face of the third member)
78 Lateral vibration transmission part (overhang part)
78A support surface 90 squeeze air linear guide (non-contact support device)
92 Slider (second member)
94 Horn (third member)
100 Squeeze air guide (non-contact support device)
102 Floating body (second member)
110 Squeeze air spherical joint (non-contact support device)
112 Floating body (second member)
114 Horn (third member)
116 Longitudinal vibration transmission part (third member)
116A lower end surface (one end surface of the third member)
116B Support surface (the other end surface of the third member)
118 Lateral vibration transmission part (overhang part)
118A Support surface

Claims (13)

A vibrator that is driven to generate ultrasonic vibration;
A support surface and a second member formed on the outer peripheral portion by holding the vibration body coaxially between one end surface in the axial direction and the first member and holding the vibration body and exciting the vibration body. A third member that generates an air film for maintaining a non-contact state with the second member between
A non-contact support device. The vibrator is a piezoelectric element that can generate ultrasonic vibration by a piezoelectric effect,
The non-contact support device according to claim 1, wherein the third member is sandwiched in a compressed state with the vibration generating body between the first member and the first member.   When the third member is vibrated by the vibrator, the third member is not in contact with the second member via an air film generated between the support surface and the other end surface in the axial direction and the second member. The non-contact support device according to claim 1, wherein the contact state is maintained.   The non-contact support device according to any one of claims 1 to 3, wherein the support surface of the third member is a cylindrical surface coaxial with the third member.   The third member is designed so that an axial length thereof is a natural number times 1/4 of a wavelength of an ultrasonic wave that is vibrated by the vibrator and transmitted through the third member. The non-contact support device according to any one of claims 1 to 4.   The non-contact support device according to any one of claims 1 to 5, wherein the third member has a projecting portion that projects in a direction orthogonal to the axis and has the support surface formed on an outer peripheral portion.   The overhanging portion protrudes in a direction orthogonal to the axis of the third member from a node position of an ultrasonic wave that is vibrated by the vibrator in the third member and is transmitted in the axial direction of the third member. The non-contact support device according to claim 6.   The third member is designed such that the distance from the axial center to the support surface of the overhanging portion is ¼ of the wavelength of the ultrasonic wave that is vibrated by the vibrator and transmitted through the third member. The non-contact support device according to claim 7.   9. The support surface of the overhanging portion is formed on both sides in the axial direction with respect to a node position of an ultrasonic wave that is vibrated by the vibrator and transmitted through the third member in the axial direction. The non-contact support apparatus of any one of Claims.   The non-contact support device according to any one of claims 1 to 9, wherein the support surface includes a tapered surface that faces both a radially outer side and an axial end of the third member.   The non-contact support device according to any one of claims 1 to 10, wherein the third member is a support body that is supported by a machine base and supports the second member as a supported body in a non-contact manner.   The non-contact support device according to claim 11, wherein the third member is supported by the machine base via the first member.   The non-contact support device according to claim 12, wherein the first member is fixed to the machine base at a flange extending along an end surface that contacts the vibration generator.

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