JP2015197109A - Gas spring type vibration proof device and vibration-proof table - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a variable directional property of spring property in a horizontal direction of a vibration proof device.SOLUTION: An upper rotating member 52 is arranged at a position corresponding to an upper end part of a support rod 31 at a lower surface of a load disc 29. The lower surface of the upper rotating member 52 acts as an upper cylindrical surface 53 bulged out downwardly. The upper end part of the support rod 31 is provided with a lower rotating member 52. The upper surface of the upper rotating member 52 is bulged out above it and becomes a lower side cylindrical surface 54 abutted against the upper cylindrical surface 53. The upper cylindrical surface 53 is constituted in such a way that it is rotatable in a horizontal direction in respect to the lower side cylindrical surface 54.

Description

  The present invention relates to a gas spring vibration isolator that elastically supports a supported body with a gas spring and a vibration isolation table provided with the same.

  Conventionally, as this type of vibration isolator, a gimbal mechanism has been incorporated into the piston of a vibration isolator using a diaphragm-type air spring, and the displacement in the horizontal direction between the supported body and the foundation is converted into a swinging motion of the piston. There is one that can obtain a soft spring characteristic in the horizontal direction by converting.

  In this vibration isolator, the piston of the air spring is divided into a disk-shaped load disk (load receiving member) and a cylindrical piston main body located below the disk, and the outer periphery of the piston main body is held by a diaphragm. A bottomed cylindrical piston well extending downward is provided at the lower end of the piston body. At the bottom of the piston well, a lower end portion of a support rod (a support member) inserted into a hollow portion in the piston well is pivotally supported. The upper end portion of the support rod protrudes upward from the upper surface of the piston body to form an enlarged diameter-expanded portion, and the entire upper surface is formed into a spherical surface that projects upward. This spherical surface is brought into contact with the lower surface of the load disk so as to be able to roll and serve as a load receiving surface. The support rod swings with respect to the load disk by rolling on the load receiving surface (see, for example, Patent Document 1).

JP 2007-321932 A

  By the way, the vibration isolation table provided with the vibration isolation device includes, for example, four vibration isolation devices on a foundation, and these vibration isolation devices support a rectangular surface plate. On the other hand, in each vibration isolator, since the load receiving surface of the support rod that contacts the lower surface of the load disk is spherical as described above, the spring characteristics in the horizontal direction are not directional.

  Therefore, if the surface plate has a square shape, for example, the front-rear spacing and the left-right spacing between the vibration isolation devices are substantially the same, the horizontal characteristics of the vibration isolation table have no directionality, and the surface plate and the mounted A mode that rotates in the horizontal direction around the center of gravity of the object to be vibration-damped is generated. However, there is a demand for vibration isolation while making the front-rear spacing and the left-right spacing between the vibration isolators substantially the same and maintaining the direction of the spring characteristics in the horizontal direction without generating a rotation mode.

  On the other hand, when the surface plate has a rectangular shape, for example, when the front-rear spacing and the left-right spacing between the vibration isolators are different, the spring characteristics in the horizontal direction of the anti-vibration table are directional. Mode does not occur. However, there is also a demand for vibration isolation while generating a rotation mode while differentiating the front-rear interval and the left-right interval between the vibration isolation devices.

  The present invention has been made in view of the above points, and an object thereof is to make the directionality of the horizontal spring characteristics of the vibration isolation device variable.

  In order to achieve the above object, the present invention is provided with variable means for changing the directionality of the horizontal spring constant.

  Specifically, according to the present invention, a load receiving member that receives a load of a supported body is disposed above a case having an opening on the upper surface, and a piston that supports the load receiving member is inserted into the case from the opening. The lower end surface of the piston is made to face the inside of the case, and the load from the outer periphery of the piston to the periphery of the opening of the case is closed by an annular flexible member. The following solution was taken for a gas spring type vibration isolator comprising a gas spring that elastically supports the above.

  That is, according to the first aspect of the present invention, the horizontal spring constant of the gas spring type vibration isolator is anisotropic, having an isotropic state, a maximum value in a predetermined direction, and a minimum value in a direction orthogonal thereto. A variable means for continuously changing between states is provided.

  According to the first aspect of the invention, the variable means causes the horizontal spring constant of the gas spring type vibration isolator to differ from the isotropic state to the maximum value in the predetermined direction and the minimum value in the direction orthogonal thereto. For example, the front-to-back distance and the left-right distance between the gas spring type vibration isolation devices in the vibration isolation table are substantially the same, and the vibration isolation object rotates in the horizontal direction. If you dislike it, set the horizontal spring constant of each gas spring type vibration isolator to the anisotropic state by the variable means, and set the horizontal spring constant of all the gas spring type vibration isolator to the predetermined direction. By making the minimum value in the direction orthogonal to the center, it is possible to prevent the vibration isolation object from rotating about its center of gravity. On the other hand, for example, when the front-rear interval and the left-right interval between the gas spring type vibration isolation devices in the vibration isolation table are different and the vibration isolation object rotates in the horizontal direction around its center of gravity, By making the spring constant in the horizontal direction of the gas spring type vibration isolator an isotropic state by a variable means, when the object to be isolated rotates around its center of gravity, the vibration is isolated so as to absorb the rotation. It becomes possible to do.

  According to a second invention, in the first invention, the variable means includes an upper cylindrical surface formed so as to project downward to a position corresponding to an upper end portion of the piston on a lower surface of the load receiving member, and the piston A lower cylindrical surface that is formed so as to project upward at the upper end portion and abuts against the upper cylindrical surface, and one of the cylindrical surfaces is configured to be rotatable in the horizontal direction with respect to the other. It is characterized by that.

  According to the second invention, when the horizontal spring constant is isotropic, the central axis of one cylindrical surface is rotated so as to be orthogonal to the central axis of the other cylindrical surface. Thus, the spherical surfaces are substantially in contact with each other. For this reason, the spring constant in the horizontal direction is isotropic. Then, from this isotropic state, by rotating one cylindrical surface in the horizontal direction with respect to the other cylindrical surface, the vertical distance between both cylindrical surfaces gradually changes, and the horizontal spring constant is continuous. To change. When the central axis of one cylindrical surface is parallel to the central axis of the other cylindrical surface, the cylindrical surfaces come into linear contact with each other along this central axis, so that the horizontal spring constant is in the direction of the central axis. It becomes an anisotropic state where the maximum value is obtained and the minimum value is obtained in a direction perpendicular to the central axis. Thus, the variable means can be configured with a relatively simple structure of a pair of cylindrical surfaces.

  The third invention is directed to a vibration isolation table in which a plurality of gas spring type vibration isolation devices according to the first or second invention are installed, and a vibration isolation object is placed on the gas spring type vibration isolation device. All of the gas spring type vibration damping devices are characterized in that the horizontal spring constant is maximized in a predetermined direction by the variable means and minimum in a direction orthogonal to the predetermined direction.

  According to the third invention, it is suitable for vibration isolation of a vibration isolation object that dislikes rotation.

  The fourth invention is directed to a vibration isolation table in which a plurality of gas spring vibration isolation devices according to the first or second invention are installed, and a vibration isolation object is placed on these gas spring vibration isolation devices. The gas spring type vibration isolator is arranged at a corner of the square on the foundation, and the pair of diagonal gas spring type vibration isolator has a horizontal spring constant in a predetermined direction by the variable means. On the other hand, the other pair of the gas spring type vibration isolator has the maximum value and the minimum value in the orthogonal direction orthogonal to the predetermined direction, and the horizontal spring constant is maximized in the orthogonal direction by the variable means. It is the minimum value in the predetermined direction.

  According to the fourth aspect of the present invention, in the layout in which the gas spring type vibration isolator is arranged at equal intervals in the front and rear, right and left, it is suitable for vibration isolation of a rotating vibration isolation object.

  As described above, according to the present invention, the variable means allows the horizontal spring constant of the gas spring type vibration isolator to be different from the isotropic state and the maximum value in the predetermined direction and the minimum value in the direction orthogonal thereto. For example, the front-to-back distance and the left-right distance between the gas spring type vibration isolation devices in the vibration isolation table are substantially the same, and the vibration isolation object rotates in the horizontal direction. If you dislike it, set the horizontal spring constant of each gas spring type vibration isolator to the anisotropic state by the variable means, and set the horizontal spring constant of all the gas spring type vibration isolator to the predetermined direction. By making the minimum value in the direction orthogonal to the center, it is possible to prevent the vibration isolation object from rotating about its center of gravity. On the other hand, for example, when the front-rear interval and the left-right interval between the gas spring type vibration isolation devices in the vibration isolation table are different and the vibration isolation object rotates in the horizontal direction around its center of gravity, By making the spring constant in the horizontal direction of the gas spring type vibration isolator an isotropic state by a variable means, when the object to be isolated rotates around its center of gravity, the vibration is isolated so as to absorb the rotation. It becomes possible to do.

It is a perspective view which shows typically the whole structure of the precision vibration isolator which concerns on embodiment of this invention. It is a top view which shows typically the precision vibration isolator which concerns on embodiment of this invention. It is the III-III sectional view taken on the line of FIG. It is a figure which shows an upper side rolling element, Comprising: (a) is a top view, (b) is a front view. It is a figure which shows a lower side rolling element, Comprising: (a) is a top view, (b) is a front view, (c) is a side view. FIG. 4 is a view corresponding to FIG. 3 in a state in which the upper rolling element is orthogonal to the lower rolling element. It is a top view which shows typically the precision vibration isolator in the state which rotated the positioning plate of a pair of diagonal isolator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the following description of preferable embodiment is only an illustration essentially, and is not intending restrict | limiting this invention, its application thing, or its use.

  FIG. 1 is a perspective view showing an example of a precision vibration isolation table A using the gas spring type vibration isolation device according to this embodiment, and FIG. 2 is a plan view schematically showing the precision vibration isolation table A. . This precision vibration isolation table A is equipped with, for example, precision equipment such as a semiconductor inspection device, an electron microscope, and an optical measurement device (not shown), and the equipment is installed in a state of being substantially insulated from vibration from the floor surface. belongs to. As shown in FIG. 1, the precision vibration isolation table A includes a lower structure portion 1 installed on a floor surface and gas spring vibration isolation devices respectively disposed at four corners of the upper surface of the lower structure portion 1. And the mounting board 3 mounted on top of these four isolators 2. Note that the lower side and the upper side in FIG. 2 are the front side and the rear side, respectively, and the right side and the left side in FIG. 2 are the right side and the left side.

  The lower structure portion 1 is a structure in which structural members of a steel square pipe are assembled so as to have a substantially rectangular parallelepiped shape. The lower structure portion 1 includes four leg portions 4 extending in the vertical direction, and two adjacent leg portions 4 of the four leg portions 4 in the horizontal direction so as to be connected at the lower end side. The lower beam portion 5 extends and the upper beam portion 6 is disposed in a square frame shape in plan view so as to surround the outer periphery of the upper ends of the four leg portions 4. The inner surface of the upper beam portion 6 is joined to the outer surface of each leg portion 4, and the upper surface of the upper beam portion 6 is positioned on the same plane as the upper end surface of each leg portion 4.

  A horizontal plate 7 is disposed from the upper end surface of each leg portion 4 to the upper surface of the upper beam portion 6 that surrounds the outside thereof, and the isolator 2 is disposed on each horizontal plate 7. . Further, two moving casters 8 are disposed on the lower surface of the lower beam portion 5 extending in the longitudinal direction of the lower structure portion 1, and a height adjustment leveler is provided on the lower end surface of each leg portion 4. 9 is disposed.

  3 is a cross-sectional view taken along line III-III in FIG. The isolator 2 incorporates a gimbal mechanism into the piston of a diaphragm-type air spring as in the conventional example (Patent Document 1), and in addition to the original characteristic of an air spring that is soft in the vertical direction, It is designed to obtain soft characteristics.

  Specifically, the isolator 2 includes a rectangular box-shaped case 11 fastened to the upper surface of the horizontal plate 7. Although this case 11 is not shown in detail, a side wall is erected on a bottom plate made of a metal plate material, and a top plate formed on the upper surface of the case 11 is joined to an upper end of the case 11, and an opening is provided at the approximate center of the top plate. Part 11a. A piston 12 is inserted into the case 11 from the opening 11a of the top plate.

  The piston 12 includes a piston main body 13 disposed immediately above the opening 11 a on the upper surface of the case 11, a bottomed cylindrical piston well 23 as a downward extending portion extending downward from the piston main body 13, and the piston well And a support rod 31 as a support member inserted into the hollow portion 24 of the head 23. The outer periphery of the piston well 23 to the periphery of the opening 11a on the upper surface of the case 11 is closed by an annular diaphragm 15 that is a flexible member.

  The piston body 13 has a donut shape having a center hole 14 having a circular cross section penetrating in the vertical direction. The center hole 14 has a stepped shape having a reduced diameter at the lower end. That is, the lower end portion of the center hole 14 constitutes a small diameter portion 14a formed with a relatively small diameter, and the other upper portion constitutes a large diameter portion 14b formed with a relatively large diameter. . As a result, an annular bottom surface portion 13 a is formed in the center hole 14 of the piston body 13. Although not shown, a taper surface that is slightly reduced in diameter toward the lower end side is formed on at least the lower half of the outer peripheral surface of the piston body 13.

  The diaphragm 15 is disposed so as to reach the periphery of the opening 11 a on the upper surface of the case 11 after covering the outer peripheral tapered surface from the lower end surface 13 b of the piston body 13. That is, the opening 11 a on the upper surface of the case 11 is closed by the diaphragm 15 and the piston main body 13 to partition the air chamber 17, and the lower end surface 13 b of the piston main body 13 faces the air chamber 17 and receives its internal pressure. The air spring 18 is mainly configured to support the load in the vertical direction.

  The diaphragm 15 is formed in a substantially dish shape by a rubber elastic film in which a woven fabric such as polyester fiber is embedded as a reinforcing material, and is continuous with an inner peripheral portion 15a bonded to the lower end surface 13b of the piston body 13 and the outer peripheral side thereof. Then, it is composed of an annular roll portion 15b that is curved so as to be convex upward, and an outer peripheral flange portion 15c that is continuously provided in a bowl shape on the outer peripheral side.

  The inner peripheral portion 15 a of the diaphragm 15 is pressure-bonded to the piston main body 13 by a washer 19 from below. On the other hand, the outer peripheral flange portion 15 c of the diaphragm 15 is bonded to the peripheral portion of the opening 11 a on the upper surface of the case 11, and the tightening ring 21 disposed on the upper side thereof is fastened to the top plate of the case 11 by the bolt 22. Thus, the top plate of the case 11 and the fastening ring 21 are sandwiched.

  The diaphragm 15 arranged in this way is large with respect to the displacement of the piston body 13 in the vertical direction because the annular roll portion 15b is bent so as to swell up and down between the piston body 13 and the tightening ring 21. The piston main body 13 easily swings around a horizontal axis when the annular roll portions 15b on both the left and right sides sandwiching the piston main body 13 are bent in opposite directions in the vertical direction. It is like that. On the other hand, since the diaphragm 15 has very little flexibility with respect to the displacement of the piston body 13 in the horizontal direction, the piston body 13 hardly displaces in the horizontal direction.

  The upper end portion of the piston well 23 is slightly reduced in diameter to be a reduced diameter portion 23 a that is screwed into the small diameter portion 14 a of the central hole 14 of the piston body 13 and protrudes into the large diameter portion 14 b of the central hole 14. Yes. Then, the male screw provided on the outer peripheral surface of the reduced diameter portion 23a is screwed with the female screw provided on the inner peripheral surface of the small diameter portion 14a in the center hole 14 of the piston body 13, and among the reduced diameter portion 23a. The portion of the center hole 14 that protrudes from the large diameter portion 14 b is fastened with a bearing nut 25, whereby the reduced diameter portion 23 a of the piston well 23 is fastened to the piston body 13 together with the washer 19.

  A steel well slug 26 having a slightly smaller diameter and a thick disk shape is joined to the bottom surface of the hollow portion 24 of the piston well 23, and the bottom wall portion 23 b of the piston well 23 is bolted from below with a bolt 27. The well slug 26 is the bottom of the piston well 23. The upper surface of the well slug 26 is subjected to a quenching process for increasing the surface hardness.

  The support rod 31 extends in the vertical direction through the hollow portion 24 of the piston well 23, and a lower end portion thereof is pivotally supported by the bottom portion of the piston well 23. That is, a reduced diameter portion 31a having a relatively small diameter is formed at the lower end portion of the support rod 31, and the steel ball 33 is accommodated in the concave portion 32 opened at the distal end surface of the reduced diameter portion 31a (lower end surface of the support rod 31). The lower part (spherical protrusion) of the steel ball 33 protrudes from the lower end of the support rod 31 and abuts against the upper surface of the well slug 26 so as to be able to roll.

  A holding member 35 made of a rubber elastic body is disposed on the bottom side of the hollow portion 24 of the piston well 23 so as to cover the outer peripheral surface of the reduced diameter portion 31 a of the support rod 31 to the outer peripheral surface of the well slug 26. doing. The holding member 35 is mainly composed of, for example, fluoro rubber, covers the steel ball 33 from the outer peripheral surface of the reduced diameter portion 31a of the support rod 31, and further covers the entire outer peripheral surface from the upper surface of the well slug 26. These reduced diameter portions 31a, steel balls 33 and well slugs 26 are integrally vulcanized and bonded to each other.

  Further, the outer peripheral side of the holding member 35 gradually increases in diameter downward from the upper end of the reduced diameter portion 31a of the support rod 31, and moves downward while closely contacting the inner peripheral surface of the hollow portion 24 of the piston well 23 on the entire circumference. It is made into the substantially cylindrical shape extended. Further, an annular groove 35a is formed on the outer peripheral surface of the holding member 35 over the entire circumference in the horizontal direction at a position near the lower end of the reduced diameter portion 31a of the support rod 31 when viewed from the horizontal direction. As a result, the holding member 35 is easily bent to bend and deform in all horizontal directions.

  On the other hand, an insertion hole 31 b that opens upward is formed at the upper end of the support rod 31. The lower rolling element 50 is attached to the insertion hole 31b. The support rod 31 supports, via the lower rolling element 50, a load disk 29 that receives the load of the mounting board 3 as a supported body and the precision equipment mounted thereon from above.

  The load disk 29 is spaced above the piston body 13. The outer shape of the load disk 29 is a track shape slightly smaller than the top plate of the case 11 (see FIG. 2), and when a moderate air pressure is supplied to the air chamber 17, the outer peripheral side of the lower surface of the load disk 29 Is spaced apart from the lower clamping ring 21 and opposed to the upper surface of the clamping ring 21. The load disk 29 is fitted in a track-shaped fitting hole 49a formed in a positioning plate 49 provided on the outer periphery thereof.

  A square-shaped through hole 51 is formed at a portion corresponding to the upper end portion of the support rod 31 of the load disk 29. The through-hole 51 has a stepped shape in which a portion on the lower opening end side located below is enlarged in diameter. That is, of the through hole 51, the lower opening end side portion forms a relatively wide portion 51a, and the other portion includes a relatively narrow portion 51b. It is composed. An upper rolling element 52 is fitted into the narrow portion 51 b of the through hole 51 of the load disk 29.

  4A and 4B are diagrams showing the upper rolling element 52, where FIG. 4A is a plan view and FIG. 4B is a front view. The upper rolling element 52 includes an upper abutting portion 52a having a square shape larger than the narrow portion 51b of the through hole 51 in a plan view having a cylindrical surface 53 (hereinafter referred to as an upper cylindrical surface 53) projecting downward. The upper abutting portion 52a protrudes upward from the upper surface, and has a square-shaped fitting portion 52b that fits into the narrow portion 51b of the through hole 51 in plan view. The upper cylindrical surface 53 extends in the front-rear direction around a central axis 53a extending in the front-rear direction.

  The upper rolling element 52 is in contact with the lower rolling element 50 on the lower side. 5A and 5B are diagrams showing the lower rolling element 50, where FIG. 5A is a plan view, FIG. 5B is a front view, and FIG. 5C is a side view. The lower rolling element 50 is a cylindrical boss 50b that is screwed into the insertion hole 31b formed in the upper end portion of the support rod 31, and a cylinder that is provided at the upper end of the boss 50b and whose upper surface projects upward. And a lower abutting portion 50a forming a surface 54 (hereinafter referred to as a lower cylindrical surface 54). The lower contact portion 50a has substantially the same square shape as the upper contact portion 52b in a plan view, and the lower cylindrical surface 54 is centered on a central axis 54a extending in the front-rear direction. It is parallel to the central axis 53 a of the upper cylindrical surface 53 of the moving element 52 and is in contact with the upper cylindrical surface 53 of the upper rolling element 52. Therefore, these cylindrical surfaces 53 and 54 are in contact with a linear shape extending in the front-rear direction. Accordingly, the lower rolling element 50 cannot roll in the front-rear direction with respect to the upper rolling element 52, but the vertical distance between both cylindrical surfaces 53 and 54 is maximized, and thus the maximum in the left-right direction. Can roll. For this reason, the spring constant in the horizontal direction of the isolator 2 becomes an anisotropic state in which the maximum value is obtained in the front-rear direction and the minimum value in the left-right direction.

  The upper rolling element 52 and the lower rolling element 50 are surrounded by a holder 55 having a square frame shape. The holder 55 is made of rubber, is fitted into the wide portion 51a of the through hole 51 of the load disk 29, and is in close contact with the outer peripheral surface of the upper contact portion 52a so that the upper contact portion 52a is connected to the load disk. 29, the upper fixed portion 55a fixed to the upper fixed portion 55, and extends downward from the periphery of the opening of the upper fixed portion 55a. And a lower fixing portion 55b that prevents the position of the child 52 from shifting. Therefore, the lower rolling element 50 and the upper rolling element 52 are held by the holder 55 so that the central axes 53a and 54a of both the cylindrical surfaces 53 and 54 are parallel to each other.

  Although not shown, the case 11 is provided with an air supply / exhaust passage to the air chamber 17. The supply / discharge passage is connected to an air reservoir tank by an air pipe, and supplies and discharges air between the reservoir tank and the air chamber 17. In the middle of the air pipe, an orifice for attenuating fluctuations in air pressure due to air flow resistance, a valve for discharging air from the air chamber 17 to the atmosphere, and the like are disposed. Further, as shown in FIG. 2, an automatic leveling device 60 is disposed on the side of the case 11 of the three vibration isolation devices 2, 2, 2 among the four vibration isolation devices 2, 2,. Yes.

  In the isolator 2 configured as described above, the piston main body 13, the piston well 23, the support rod 31 and the like integrally move up and down to function as a gimbal piston in which a gimbal mechanism is incorporated in the piston 12 of the air spring 18, and the piston main body 13 Further, the piston well 23 and the support rod 31 oscillate, so that the gimbal piston exhibits a very soft spring characteristic in the horizontal direction. That is, in the gimbal piston, the piston body 13 and the piston well 23 are integrally swung with respect to the case 11 and the support rod 31 is swung with respect to the load disk 29. It absorbs the displacement in the horizontal direction.

  At that time, since the lower rolling element 50 is in linear contact with the upper rolling element 52 in the front-rear direction, it can roll in the left-right direction. Then, the stress generated in the left-right direction on the holder 55 as the lower rolling element 50 rolls in the left-right direction acts as a damper that suppresses the swinging of the support rod 31, and the support rod 31, and consequently the piston 12. The horizontal vibration that occurs in is attenuated. On the other hand, since the lower rolling element 50 is in contact with the upper rolling element 52 in a linear shape extending in the front-rear direction, it cannot roll in the front-rear direction, and the spring constant in the front-rear direction becomes the maximum value. . For this reason, it is possible to prevent the rotation mode in which the mounting board 3 and the precision equipment mounted thereon rotate about the center of gravity.

  On the other hand, the upper rolling element 52 can be rotated in the horizontal direction with respect to the lower rolling element 50 by the rotation of the positioning plate 49. During this rotation, the vertical distance between the upper cylindrical surface 53 and the lower cylindrical surface 54 changes, and the spring constant in the front-rear direction gradually decreases, while the spring constant in the left-right direction gradually increases.

  As shown in FIG. 6, the upper rolling element 52 is arranged so that the central axis 53 a of the upper cylindrical surface 53 thereof is orthogonal to the central axis 54 a of the lower cylindrical surface 54 of the lower rolling element 50. As a result, the upper cylindrical surface 53 and the lower cylindrical surface 54 are in point contact, and the distance between the cylindrical surfaces 53 and 54 is maximized. Will contact with a spherical shape. Therefore, the horizontal spring constant of the isolator 2 is isotropic. That is, the isolator 2 is substantially provided with a dome gimbal mechanism.

  As described above, both the rolling elements 50 and 52 can continuously change between the isotropic state and the anisotropic state by the rotation of the positioning plate 49. Therefore, both the rolling elements 50 and 52, the load disk 29, and the positioning plate 49 continuously change the horizontal spring constant of the isolator 2 between an isotropic state and an anisotropic state. The variable means to make is comprised.

  Next, FIG. 7 shows each of the lower and upper rolling elements 50, 2 of the two isolators 2, 2 on the front left side and the rear right side of the four isolators 2, 2,. 52, the positioning plate 49 is rotated so that the central axes 53a and 54a extend in the left-right direction. As a result, the horizontal spring constants of the two front left and rear right isolators 2 and 2 have a maximum value in the left-right direction and a minimum value in the front-rear direction. Therefore, the mounting board 3 can slide so as to rotate in the horizontal direction.

  Therefore, when the device mounted on the mounting board 3 rotates around its center of gravity, the vibration of the mounted device can be isolated while absorbing the rotation.

-Effects of the embodiment of the invention-
According to the above embodiment, by rotating the upper rolling element 52 in the horizontal direction, the horizontal spring constant of the isolator 2 is set to an isotropic state, a maximum value in a predetermined direction, and a direction orthogonal thereto. It is possible to continuously change between the anisotropic state that is the minimum value. Therefore, when the mounted device does not like horizontal rotation, the horizontal spring constant of each isolator 2 is set to an anisotropic state, and the horizontal spring constants of all the isolators 2 are set in the front-rear direction. By setting the maximum value to the maximum value and the minimum value in the left-right direction, it is possible to prevent the mounting board 3 and the mounted device from rotating about the center of gravity. On the other hand, when the mounted device rotates in the horizontal direction, the mounting board 3 and the mounted device rotate around the center of gravity by setting the horizontal spring constant of each isolator 2 in an isotropic state. In this case, vibration isolation can be performed so as to absorb the rotation.

  Further, according to the embodiment, when the horizontal spring constant is isotropic, the central axis 53a of the upper cylindrical surface 53 is orthogonal to the central axis 54a of the lower cylindrical surface 54. , The lower rolling element 50, which is substantially the upper end portion of the support rod 31, comes into contact with the load disk 29 on a spherical surface. For this reason, the spring constant in the horizontal direction is isotropic. Then, by rotating the upper cylindrical surface 53 in the horizontal direction with respect to the lower cylindrical surface 54 from this isotropic state, the vertical distance between the cylindrical surfaces 53 and 54 gradually changes, and the horizontal direction The spring constant changes continuously. When the central axis 53a of the upper cylindrical surface 53 is parallel to the central axis 54a of the lower cylindrical surface 54, the cylindrical surfaces 53 and 54 come into contact with each other in a linear shape extending in the front-rear direction, so that the horizontal spring constant is increased. It becomes an anisotropic state in which the maximum value in the direction and the minimum value in the left-right direction. Thus, the variable means can be configured with a relatively simple structure of a pair of cylindrical surfaces 53 and 54.

  Furthermore, according to the above-described embodiment, even in a layout in which the isolators 2, 2,... Are arranged at equal intervals in the front, rear, left, and right directions, all the isolators 2, 2,. By arranging 54a so as to extend in the front-rear direction, it is suitable for vibration isolation of an on-board device that dislikes rotation.

  Furthermore, according to the above embodiment, in the layout in which the isolators 2, 2,... Are arranged at equal intervals in the front, rear, left, and right, the front left and rear right isolators 2, 2 are connected to the central axes 53a, 53a, 54c of the cylindrical surfaces 53, 54, respectively. By arranging 54a so as to extend in the left-right direction, it is suitable for vibration isolation of a mounted device that rotates.

(Other embodiments)
In the above embodiment, the upper contact portion 52a on which the upper cylindrical surface 53 is formed and the lower contact portion 50a on which the lower cylindrical surface 54 is formed have a square shape in plan view, but the present invention is not limited to this. For example, it may be circular. When these contact portions 50a and 52a are circular, the holder 55 has a circular frame shape in accordance with the outer peripheral ends of the contact portions 50a and 52a, and the holder 55 is attached to the load disk 29. Thus, the upper rolling element 50 can be rotated in the horizontal direction. In this case, a drive mechanism that rotates the positioning plate 49 in the horizontal direction around the upper rolling element 52 may be provided, and the positioning plate 49 may be automatically rotated by this drive mechanism.

  In the above embodiment, the isolators 2, 2,... Are arranged at the corners of the square, but the present invention is not limited thereto, and may be arranged at the corners of the rectangle.

  As described above, the gas spring type vibration damping device and the vibration damping table using the gas spring vibration damping device according to the present invention can be applied to applications in which the directionality of the horizontal spring characteristics of the vibration damping device is variable.

1 Lower structure (basic)
2 Isolator (Gas spring type vibration isolator)
11 Case 11a Opening 12 Piston 13 Piston Body 14 Center Hole 15 Diaphragm (Flexible Member)
23 Piston well (lower extension)
24 hollow part 29 load disk (load receiving member, variable means)
31 Support rod (support member)
49 Positioning plate (variable means)
50 Lower rolling element (variable means)
52 Upper rolling element (variable means)
53 Upper cylindrical surface (variable means)
54 Lower cylindrical surface (variable means)

Claims (4)

A load receiving member that receives the load of the supported body is disposed above a case having an opening on the upper surface, and a piston that supports the load receiving member is inserted into the case from the opening, and a lower end surface of the piston A gas spring that elastically supports the load of the supported body by closing the outer periphery of the piston to the periphery of the opening of the case with an annular flexible member. A gas spring vibration isolator configured,
The spring constant in the horizontal direction of the gas spring type vibration isolator is continuously between an isotropic state and an anisotropic state where the maximum value is in a predetermined direction and the minimum value is in a direction perpendicular thereto. A gas spring type vibration isolator comprising variable means for changing. In the gas spring type vibration isolator according to claim 1,
The variable means is formed so as to project upward to an upper cylindrical surface formed to project downward to a position corresponding to the upper end of the piston on the lower surface of the load receiving member, and to the upper end of the piston. And a lower cylindrical surface that abuts on the upper cylindrical surface, and one of the two cylindrical surfaces is configured to be rotatable in the horizontal direction with respect to the other cylindrical surface. . A plurality of gas spring vibration isolation devices according to claim 1 or 2 are installed on a foundation, and a vibration isolation table on which a vibration isolation object is placed on the gas spring vibration isolation device,
All the gas spring type vibration damping devices are characterized in that each horizontal spring constant has a maximum value in a predetermined direction and a minimum value in a direction orthogonal to the predetermined direction by the variable means. Spring type vibration isolator. A plurality of gas spring vibration isolation devices according to claim 1 or 2 are installed on a foundation, and a vibration isolation table on which a vibration isolation object is placed on the gas spring vibration isolation device,
The gas spring vibration isolator is disposed at the corner of the square on the foundation,
While the pair of gas spring type vibration isolator on the diagonal, the horizontal spring constant becomes the maximum value in the predetermined direction by the variable means, and the minimum value in the orthogonal direction orthogonal to the predetermined direction,
The other pair of the gas spring type vibration damping devices is characterized in that the horizontal spring constant is a maximum value in the orthogonal direction and a minimum value in the predetermined direction by the variable means. Shaker.

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