JP2011099543A - Vibration resistant device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely establish grounding for a control board arranged at a surface plate in a vibration resistant device in which the surface plate for placing equipment is supported relative to a foundation by a supporting spring element. <P>SOLUTION: The vibration resistant device includes the control board arranged at the surface plate 5 and controlling a vertical and a horizontal linear motor unit, and a grounding coil spring 10 in contact with a surface plate 5 side and a foundation member 2 side, and making conductive between the surface plate 5 and the foundation member 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vibration isolator formed by supporting a surface plate on which equipment is mounted with a support spring element with respect to a foundation.

  For example, a surface plate on which equipment that is susceptible to vibration, such as electron microscopes, atomic force microscopes, semiconductor-related testing equipment, and precision measuring equipment such as inspection equipment, is mounted is supported by a spring element against the foundation. Such a vibration isolator is known as the prior art. Hereinafter, a conventional vibration isolator will be described with reference to Patent Document 1.

  The vibration isolator shown in Patent Document 1 includes a base member, coil springs as spring elements respectively disposed at the four corners of the upper surface of the base member, and four corners supported by these coil springs on the upper surface. And a surface plate on which the device is placed.

  In addition, adjacent to each of the four coil springs, vertical and horizontal linear motor units are arranged between the surface plate and the base member so that they are relatively displaced by several millimeters in the vertical and horizontal directions, respectively. It is installed. Each of the linear motor units is disposed so as to apply vertical and horizontal forces from the base member to the surface plate.

  The vertical and horizontal linear motor units have built-in acceleration sensors, respectively, thereby detecting the vertical and horizontal relative accelerations relative to the base member of the surface plate and outputting them to the control base. Yes.

  A signal output from the acceleration sensor of the vertical linear motor unit for each coil spring is input to the control board, while a drive control signal generated based on this signal is sent from the control board to the linear motor unit. As a result, a control force that reduces vibrations in the vertical direction is added to the surface plate and the equipment. Also in the horizontal direction, vibration control similar to that in the vertical direction is performed based on a signal from the acceleration sensor of the horizontal linear motor unit.

JP 2007-78122 A

  By the way, when a control board for controlling a predetermined control object, such as a control board for controlling the vertical and horizontal linear motor units, is provided on the surface plate, in order to prevent electromagnetic waves from entering the control board, It is necessary to securely ground the control board.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a vibration isolator that supports a base plate on which a device is placed by a support spring element with respect to a foundation. The purpose is to ensure that the control board provided on the panel is grounded.

  1st invention is the vibration isolator which supports the surface plate by which an apparatus is mounted by the support spring element with respect to a foundation, Comprising: Control provided in the said surface plate and controlling a predetermined | prescribed control object And a grounding spring element that is in contact with the surface plate side and the base side and conducts between the surface plate and the base.

  According to this, since the grounding spring element which is in contact with the surface plate side and the base side and conducts between the surface plate and the base is provided, the ground for the control base provided on the surface plate must be securely taken. Can do.

  According to a second aspect, in the first aspect, the grounding spring element has a smaller spring constant than the supporting spring element.

  By the way, it is generally considered to provide ground wires, gaskets, and fingers that conduct between the surface plate and the foundation in order to ensure the grounding of the surface plate control base. However, these spring constants vary. Therefore, the natural frequency of the vibration isolator increases, and the vibration isolation performance may deteriorate.

  Here, according to the present invention, since the spring constant of the grounding spring element is smaller than that of the supporting spring element, it is possible to suppress the natural frequency of the vibration isolation device from being increased by the grounding spring element. It is possible to suppress deterioration of the vibration isolation performance.

  A third invention is characterized in that, in the first or second invention, the grounding spring element is a grounding coil spring provided so that a spring axial direction coincides with a vertical direction. .

  According to this, since the grounding spring element is constituted by the grounding coil spring provided so that the spring axial direction coincides with the vertical direction, the ground for the control base of the surface plate can be saved without taking up space. Can be taken reliably.

  A fourth invention further comprises at least one regulating member for regulating that the height position of the surface plate is vertically above a predetermined height position in the third invention, The grounding coil spring is provided on at least one of the restricting members.

  According to this, at least one restricting member for restricting the height position of the surface plate to be vertically above the predetermined height position is provided, and the grounding coil spring is provided as at least one of the restricting members. Since it is provided, it is possible to reliably ground the control base of the surface plate using the regulating member.

  According to a fifth invention, in the fourth invention, an insertion hole is formed in the foundation so as to correspond to the restriction member, and the restriction member is inserted into the insertion hole and the fixed hole is formed. A bar-like member provided on the board so as to extend vertically downward; and a stopper provided at the lower end of the bar-like member so as to extend in the horizontal direction, and the upper surface of the stopper is a peripheral portion of the insertion hole. The height of the surface plate is regulated to be vertically higher than the predetermined height position by contacting the lower surface of the plate, and the grounding coil spring of the regulating member includes A flange is formed on the outer peripheral surface of the stopper, and the grounding coil spring is provided between the peripheral edge of the insertion hole and the flange of the stopper so as to surround the stopper. It is characterized by Than is.

  According to this, the fourth invention can be realized.

  According to a sixth invention, in the fifth invention, a portion of the stopper that is vertically above the flange is formed such that the outer diameter gradually decreases as it goes vertically upward. It is.

  According to this, the portion of the stopper that is vertically above the flange is formed so that the outer diameter gradually decreases as it goes vertically upward. Therefore, the portion of the stopper that is vertically above the flange and the grounding coil A gap is formed between the spring and the spring constant in the horizontal direction of the grounding coil spring. Therefore, it is possible to further suppress the natural frequency of the vibration isolation device from being increased by the ground coil spring, and it is possible to further suppress deterioration of the vibration isolation performance.

  According to a seventh invention, in any one of the first to sixth inventions, the predetermined control target is an actuator that applies a control force to the equipment or the surface plate, and the control base is the equipment or The actuator is controlled so as to reduce the vibration of the surface plate.

  According to this, it is possible to reliably take the ground of the control base for controlling the actuator that applies the control force to the equipment or the surface plate so as to reduce the vibration of the equipment or the surface plate. It is possible to suppress the vibration isolation performance from deteriorating due to the incidence of electromagnetic waves.

  According to the present invention, since the grounding spring element that is in contact with the surface plate side and the base side and conducts between the surface plate and the base is provided, the grounding of the control base provided on the surface plate is surely taken. be able to.

It is a top view which shows schematic structure of the vibration isolator which concerns on embodiment of this invention. It is a top view which shows the structure of a base member. It is a side view which shows the structure of the coil spring part for support. It is a disassembled sectional view which shows the structure of a surface plate. It is a side view which shows the structure of a clamp part. It is a disassembled side view which shows the structure of a clamp part.

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

  FIG. 1 is a plan view showing a schematic configuration of a precision vibration isolation table A which is an embodiment of a vibration isolation device according to the present invention. The vibration isolation table A is a device 1 (indicated by a virtual line) that is susceptible to vibration, such as a precision measuring device such as an electron microscope, an atomic force microscope (AFM), a semiconductor-related test device, or an inspection device. It is assumed that a relatively small device 1 is mainly placed according to the convenience of the user.

  As shown in the figure, the vibration isolation table A includes a base member (case) 2 installed on the upper surface of a dedicated table or table (not shown), and height adjustment mechanisms 3, 3 at the four corners of the base member 2, respectively. The supporting coil springs 4, 4,... (Supporting spring elements) arranged through the four corners are supported by these supporting coil springs 4, 4,. On the other hand, a rectangular surface plate (top plate) 5 on which the device 1 is placed is provided on the upper surface.

  In this example, the base member 2 is an aluminum alloy casting, in which a rectangular floor plate 21 and a peripheral wall 22 that surrounds the outer peripheral edge thereof are integrally formed. For example, the base member 2 has higher rigidity than a press-formed product of an iron plate. At the same time, a relatively large attenuation can be obtained as an aluminum alloy. Further, a rectangular opening 21a is formed in the center portion of the floor plate 21, and ribs 21b,...

  As shown in FIGS. 1 and 3, the height adjusting mechanism 3 includes a screw shaft 31 that is rotatably disposed so as to extend vertically upward (hereinafter simply referred to as “upper”) from the floor plate 21 of the base member 2, and A spring seat 32 which is screwed to the screw shaft 31 and holds the lower end of the coil spring 4 and a driven body fixed integrally to the screw shaft 31 at a vertically lower side (hereinafter simply referred to as a lower side) of the spring seat 32. And a gear 33. The intermediate gear 34 that meshes with the driven gear 33 is rotated by a pinion fixed to the rotating shaft of the electric motor 35, whereby the screw shaft 31 rotates and the spring seat 32 moves up and down. ing.

  The four supporting coil springs 4, 4,... Are each formed by winding a metal wire having the same cross section in a conical shape so as to become thinner as going downward. Further, as shown in FIGS. 3 and 4, the support coil springs 4, 4,... Are respectively provided at the four upper corners of the bottom surface of the surface plate 5 with the upper end portions thereof interposed through sheet-like rubber materials 46. It is accommodated in the formed circular recess 54a. As described above, since the supporting coil springs 4, 4,... Are wound with a wire so as to become thinner, the space between the inner peripheral surface of the recess 54a and the upper end of the supporting coil spring 4 is reduced. Each has a play (gap). The rubber material 46 is disposed on the bottom surface of the recess 54a, and provides damping against the relative displacement of the surface plate 5 and the base member 2, and prevents surging of the supporting coil spring 4. As described above, the upper ends of the supporting coil springs 4, 4,... Are accommodated in the recess 54 a via the rubber material 46, and there is a backlash between the recess 54 a and the upper end of the coil spring 4. For this reason, the supporting coil springs 4, 4,... Cannot be reliably connected between the base member 2 and the surface plate 5, and the grounding of the control base 8 provided on the surface plate 5 is surely taken. I can't.

  In this embodiment, the surface plate 5 is configured by laminating a first aluminum layer 53 that has been anodized and a second aluminum layer 54 that has not been anodized in this order. The first and second aluminum layers 53 and 54 are bonded via a non-conductive double-sided tape 55. The recess 54 a is formed by covering the upper opening end of the circular through hole formed in the second aluminum layer 54 with the first aluminum layer 53. In FIG. 3, the double-sided tape 55 is not shown for easy understanding of the drawing.

  In addition, the vertical plate and the horizontal plate 4 are arranged so as to be displaced relative to the base member 2 by several millimeters in the vertical and horizontal directions with respect to the base member 2 by four coil springs 4, 4,. Each linear motor unit 6,..., 7,. The four linear motor units 6 for vertical use are arranged upright close to the portion where the ribs 21b of the base member 2 intersect with each other, and are perpendicular to the surface plate 5 from the floor plate 21 of the base member 2. Add direction control force.

  The vertical and horizontal linear motor units 6 and 7 are the same, and an acceleration sensor (not shown) is integrally provided. A signal indicating the relative acceleration of the surface plate 5 (vibration state of the surface plate 5) is output from the acceleration sensor, and a control signal is output from the control board 8 receiving this signal to the linear motor unit 6, and the surface plate 5 And the control force which attenuates the vibration is added to the device 1. That is, as an example, active vibration isolation control of acceleration feedback is performed. As shown in FIGS. 1 and 2, the control base 8 is attached to the center of the lower surface of the surface plate 5 so as to correspond to the opening 21 a of the floor plate 21 of the base member 2, and contacts the base member 2. Arranged not to.

  Further, when the vibration isolation table A is used, a signal from a sensor (not shown) for detecting the height of the surface plate 5 is also input to the control board 8. By controlling the electric motor 35 of the height adjusting mechanism 3, the lower end position thereof is adjusted according to the elastic deformation of the coil spring 4, and the height position of the surface plate 5 with respect to the base member 2 (the floor plate 21 of the base member 2). The distance between the upper surface and the lower surface of the surface plate 5) is kept substantially constant. Further, when the vibration isolation table A is not in use, for example, when the vibration isolation table A is being transported, the control base 8 controls the electric motor 35 of the height adjustment mechanism 3 to thereby increase the height of the surface plate 5. The position is set to a predetermined maximum height position.

  Here, as described above, the grounding of the control board 8 of the surface plate 5 cannot be reliably grounded by the support coil springs 4, 4,... The vibration isolation performance may be deteriorated. More specifically, when the CE marking minimity test was performed, the vibration isolation performance deteriorated in a specific frequency range. Therefore, in this embodiment, as shown in FIGS. 1, 2, 5, and 6, the height position of the surface plate 5 with respect to the base member 2 provided on the surface plate 5 is set to a predetermined maximum height position. The control base 8 is securely grounded by using a clamp 9 (restricting member) for restricting the upper side of the control base 8 from rising. This will be described in detail below.

  Adjacent to each of the four supporting coil springs 4, 4,... (Four vertical linear motor units 6,...), On the lower surface of the surface plate 5 (in this embodiment, the second aluminum layer 54), Clamp bolt holes 54b, 54b, ... are formed. These clamp bolt holes 54b, 54b,... Are screwed with metal (in this embodiment, stainless steel) clamp bolts 91, 91,. . Each of these clamp bolts 91, 91,... Is formed by cutting one end (upper end in FIG. 5) of a round bar and attaching a head 91a larger than the diameter to the other end (lower end in FIG. 5). It arrange | positions so that the base 8 for control may be surrounded. In FIGS. 5 and 6, the double-sided tape 55 is not shown in order to make the drawings easy to see.

  Further, adjacent to each of the four supporting coil springs 4, 4,... (Four vertical linear motor units 6,...), The floor plate 21 of the base member 2 has a lidless bottom that protrudes upward. .. Are integrally formed. A circular insertion hole 21f is formed through the center of the lid 21e of the protrusion 21d so as to correspond to the clamp bolt 91. The clamp bolt 91 is inserted into the insertion hole 21f, respectively. It is inserted.

  An annular stopper 92 made of metal (in this embodiment, made of stainless steel) is supported by the head 91 a of the clamp bolt 91 so as to extend in the horizontal direction at the lower end of the clamp bolt 91. It is fitted outside. As described above, the clamp 9 includes the clamp bolt 91 and the stopper 92.

  When the height adjustment mechanism 3 sets the height position of the surface plate 5 with respect to the base member 2 to a predetermined maximum height position when the vibration isolation table A is not in use, the upper surfaces of the stoppers 92 respectively correspond to the protruding portions 21d. It is restricted that the height position of the surface plate 5 is higher than a predetermined maximum height position by contacting the lower surface of the peripheral edge portion of the insertion hole 21f in the lid portion 21e (see the two-dot chain line in FIG. 5). And is kept in that position. Thereby, the base member 2 and the surface plate 5 can be prevented from shaking when the vibration isolation table A is not used.

  An annular flange 92a is formed on the outer peripheral surface of the lower end of the stopper 92 so as to extend in the horizontal direction. A portion of the stopper 92 above the flange portion 92a (hereinafter referred to as “an upper portion of the flange portion 92a”) is formed in a tapered shape so that the outer diameter gradually decreases as it goes upward. The outer diameter of the lower end of the upper portion of the flange 92a in the stopper 92 is approximately the same as the spring diameter of the grounding coil spring 10 described later.

  Between the lower surface of the peripheral portion of the insertion hole 21f in the lid portion 21e of the protruding portion 21d and the upper surface of the flange portion 92a of the stopper 92, a conductive coil spring for grounding 10 is provided so as to surround the stopper 92, respectively. 10, ... (ground spring elements) are interposed. Each of the coil springs for earthing 10, 10,... Is formed by winding a metal wire (stainless steel in this embodiment) having the same cross section in a cylindrical shape, and the spring axis direction coincides with the vertical direction. It is arranged like this.

  In addition, each of the grounding coil springs 10, 10,... Is in contact with the lower surface of the peripheral portion of the insertion hole 21f in the lid portion 21e of the protruding portion 21d, and the lower end thereof is the upper surface of the flange portion 92a of the stopper 92. In contact with. That is, the height position of the surface plate 5 with respect to the base member 2 is changed by increasing the distance between the upper surface of the stopper 92 and the upper surface of the flange 92a to be greater than the spring length of the grounded coil spring 10 that is compressed as much as possible. Even when the bending amount of the grounding coil spring 10 changes, the grounding coil spring 10 can be kept in contact with the base member 2 side (ie, the protruding portion 21d) and the surface plate 5 side (ie, the stopper 92). It is like that. Thereby, the grounding coil springs 10, 10,... Can conduct between the base member 2 and the surface plate 5, and the control base 8 of the surface plate 5 can be securely grounded.

  Further, the ground coil springs 10, 10,... Have a much smaller spring constant than the support coil springs 4, 4,. Further, as described above, the upper portion of the flange portion 92a in the stopper 92 is formed in a tapered shape, and therefore, between the outer peripheral surface of the upper portion of the flange portion 92a in the stopper 92 and the grounding coil spring 10, Each has a gap (escape). Thereby, the horizontal spring constant of each grounding coil spring 10 can be further reduced. That is, each grounding coil spring 10 can be further softened in the horizontal direction.

-Effect-
As described above, according to the present embodiment, since the grounding coil spring 10 is provided in contact with the surface plate 5 side and the base member 2 side and conducting between the surface plate 5 and the base member 2, the surface plate 5 The grounding of the control board 8 provided in can be reliably taken.

  By the way, in order to ensure the grounding of the control base 8 of the surface plate 5, it is generally considered to provide a ground wire, a gasket, and a finger that conduct between the surface plate 5 and the base member 2. Therefore, there is a possibility that the natural frequency of the vibration isolation table A is increased and the vibration isolation performance is deteriorated.

  Here, according to the present embodiment, since the grounding coil spring 10 has a smaller spring constant than the supporting coil spring 4, the grounding coil spring 10 increases the natural frequency of the vibration isolation table A. This can be suppressed, and deterioration of the vibration isolation performance can be suppressed.

  Further, since the grounding spring element is constituted by the grounding coil spring 10 provided so that the spring axial direction coincides with the vertical direction, the grounding of the control base 8 of the surface plate 5 can be performed without taking up space. Can be taken reliably.

  Further, four clamps 9 are provided for restricting the height position of the surface plate 5 with respect to the base member 2 from being higher than a predetermined maximum height position, and all four of the ground coil springs 10 are included in the clamp 9. Therefore, it is possible to reliably ground the control base 8 of the surface plate 5 by using the clamp 9.

  Furthermore, since the outer diameter of the stopper 92 is formed so that the outer diameter gradually decreases as it goes upward, the gap between the upper portion of the stopper 92 a and the grounding coil spring 10 is increased. There is a gap in the horizontal spring constant of the grounding coil spring 10 can be further reduced. Therefore, it is possible to further suppress the natural frequency of the vibration isolation table A from being increased by the ground coil spring 10, and it is possible to further suppress the deterioration of the vibration isolation performance.

  In addition, the ground of the control base 8 for controlling the vertical and horizontal linear motor units 6 and 7 for applying control force to the equipment 1 to the surface plate 5 is reduced so as to reduce the vibration of the equipment 1 to the surface plate 5. Therefore, it is possible to prevent the vibration isolation performance from deteriorating due to the incidence of electromagnetic waves on the control board 8.

(Other embodiments)
In the above-described embodiment, four coil springs 4 that support the surface plate 5 are used.

  Furthermore, instead of the coil spring 4, for example, a rubber elastic body or a gas spring can be used. However, in the case of a gas spring, a pressure source is required, and in consideration of the fact that the rubber elastic body has a relatively large characteristic variation and its aging change is not small, the metal coil spring 4 as in the above embodiment. Most preferably, is used.

  Further, instead of the grounding coil spring 10, a grounding spring element other than a conductive coil spring may be used.

  Furthermore, in the above-described embodiment, the example in which the control base 8 for controlling the vertical and horizontal linear motor units 6 and 7 is arranged on the surface plate 5 is shown. Instead, for example, a control board for controlling a control object other than the vertical and horizontal linear motor units 6 and 7 can be arranged on the surface plate 5.

  Furthermore, in the said embodiment, although the four clamps 9 are used, this should just be one or more.

  Moreover, in the said embodiment, although the coil spring 10 for earth | ground is provided in all the four clamps 9, this should just be provided in the one or more clamps 9. FIG.

  Furthermore, in the above-described embodiment, the grounding spring element is provided in the clamp 9. However, the present invention is not limited to this. For example, the grounding spring element can be directly provided between the base member 2 and the surface plate 5 without using the clamp 9. is there.

  Furthermore, in the said embodiment, although the rod-shaped member and the stopper are made into a different body, this may be integrated.

  Moreover, in the said embodiment, although the upper part of the collar part 92a in the stopper 92 is formed in the taper shape, it does not restrict to this, For example, it forms in a step shape so that an outer diameter may decrease gradually as it goes upwards. Is also possible.

  In the above embodiment, the grounding of the control base 8 cannot be reliably grounded by the supporting coil springs 4, 4,..., But the grounding may be surely grounded. In this case, the grounding of the control base 8 can be more reliably taken by the supporting coil springs 4, 4,... And the grounding coil springs 10, 10,.

  The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is defined by the claims, and is not limited by the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the vibration isolator according to the present invention can be applied to applications that require the control board provided on the surface plate to be securely grounded.

A Precision vibration isolation table (vibration isolation device)
DESCRIPTION OF SYMBOLS 1 Apparatus 2 Base member 21f Insertion hole 4 Coil spring for support (support spring element)
5 Surface plate 6 Vertical linear motor unit (control target, actuator)
7 Horizontal linear motor unit (control target, actuator)
8 Control base 9 Clamp (Regulator)
91 Clamp bolt (bar-shaped member)
92 Stopper 10 Grounding coil spring (grounding spring element)

Claims (7)

A vibration isolator that supports a surface plate on which equipment is mounted by a supporting spring element with respect to a foundation,
A control board provided on the surface plate for controlling a predetermined control object;
An anti-vibration device comprising: a grounding spring element which is in contact with the surface plate side and the base side and conducts between the surface plate and the base. The vibration isolator according to claim 1, wherein
The vibration isolation device according to claim 1, wherein the grounding spring element has a spring constant smaller than that of the supporting spring element. In the vibration isolator according to claim 1 or 2,
The vibration isolation device according to claim 1, wherein the grounding spring element is a grounding coil spring provided such that a spring axial direction coincides with a vertical direction. The vibration isolator according to claim 3,
It further comprises at least one regulating member for regulating that the height position of the surface plate is vertically above the predetermined height position,
The vibration isolation device according to claim 1, wherein the grounding coil spring is provided in at least one of the regulating members. The vibration isolator according to claim 4,
An insertion hole is formed in the foundation so as to correspond to the restriction member,
The restricting member includes a rod-like member provided to extend vertically downward on the surface plate in a state of being inserted into the insertion hole, and a stopper provided to extend horizontally at a lower end portion of the rod-like member. And the upper surface of the stopper is in contact with the lower surface of the peripheral edge of the insertion hole, so that the height position of the surface plate is regulated to be vertically above the predetermined height position. Configured,
A flange portion is formed on the outer peripheral surface of the stopper of the regulating member provided with the grounding coil spring,
The vibration isolation device according to claim 1, wherein the grounding coil spring is provided so as to surround the stopper between a peripheral edge portion of the insertion hole and a flange portion of the stopper. The vibration isolator according to claim 5,
The vibration isolator according to claim 1, wherein a portion of the stopper that is vertically above the flange is formed such that the outer diameter gradually decreases as it goes vertically upward. In the vibration isolator as described in any one of Claims 1-6,
The predetermined control object is an actuator that applies a control force to the device or the surface plate,
The vibration isolation device according to claim 1, wherein the control board controls the actuator so as to reduce vibration of the device or the surface plate.

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