JP5108289B2 - Scale for displacement measuring device - Google Patents

Description

  The present invention relates to a displacement measuring device scale of a displacement measuring device including a displacement measuring device scale having a scale and a reading head that reads the scale facing the scale with a predetermined gap therebetween.

  Conventionally, as a scale for a displacement measuring device attached to an object to be measured, a scale plate on which a scale is formed is held on a scale plate holder so that stress is not applied, and the scale plate holder is not subjected to stress. As described above, a highly accurate scale for a displacement measuring device held by a mounting member is known.

  In Patent Document 1, the bottom surface of the scale plate is supported at two points at the Bessel point in the measurement axis direction on the upper surface of the scale plate holder, one support portion is fixed with a rigid adhesive with a small amount of deformation, and the other support portion is fixed. The scale plate is held by the scale plate holder by being elastically fixed with an elastic adhesive, and similarly, the bottom surface of the scale plate holder is supported at two Bessel points in the measurement axis direction on the top surface of the mounting member, and one support portion A scale for a displacement measuring device is disclosed, in which a rigid adhesive with a small amount of deformation is fixed and the other adhesive support is elastically fixed with an elastic adhesive.

In this way, the scale plate and scale plate holder are supported at the vessel points, respectively, to minimize the deformation in the thickness direction of both members, one of the vessel points is fixed using a rigid adhesive, and the other is elastically bonded. By enabling the displacement by the agent, it is possible to reduce internal stress applied to the scale plate and the scale plate holder and prevent the scale plate from being distorted.
Japanese Patent No. 2989140, FIG.

  However, in such a scale for a displacement measuring device, the scale plate is supported by the scale plate holder on the lower surface of the scale plate via a rigid adhesive and an elastic adhesive, so that its own weight and the coefficient of thermal expansion between both materials The scale plate bends due to the difference between the scales and the distance between the scale and the reading head varies depending on the position in the measurement axis direction, thereby reducing the measurement accuracy.

  Further, the scale plate is also bent due to the difference in thermal expansion coefficient between the scale plate holder and the object to be measured, which causes the same problem as described above.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a scale for a displacement measuring device that realizes highly accurate measurement by preventing the deflection of the scale plate.

The scale for a displacement measuring apparatus according to the present invention has a scale plate having a scale extending in the measurement axis direction, a support surface facing the bottom surface of the scale plate, and two support walls facing both side surfaces of the scale plate. A scale plate holder for supporting the scale plate, a rigid adhesive member for bonding the side surface of the central portion of the scale plate in the measurement axis direction and the support wall, the bottom surface of the scale plate, and the support surface to the measurement axis. And an attachment member for fixing the scale plate holder to the object to be measured .

  According to the first aspect of the invention, the scale plate is supported by the elastic adhesive member at a position that is evenly spaced in the measurement axis direction from the central portion in the measurement axis direction of the bottom surface, and the side surface is supported by the rigid adhesive member in the middle of these support positions. Therefore, the scale plate does not bend due to its own weight and thermal expansion, and thereby the measurement accuracy is constant over the measurement axis.

  Further, since the scale plate is supported on the scale plate holder by the adhesive member from the side surface direction and the thickness direction, even if the scale plate is attached to the object to be measured in a horizontal posture or a vertical posture, the scale plate is supported by a plurality of support points. It is held and measurement accuracy can be made constant.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a plan view of a scale for a displacement measuring apparatus according to the first embodiment of the present invention. 2 is a view taken in the direction of arrow X1 in FIG. 1, and FIG. 3 is a view taken in the direction of arrow Y1 in FIG. 4 is a cross-sectional view taken along line A-A ′ of FIG. 1, FIG. 5 is a cross-sectional view taken along line B-B ′ of FIG. 1, and FIG. 6 is a cross-sectional view taken along line C-C ′ of FIG.

  This displacement measuring scale plate 100 includes a scale plate 1 having a scale formed on the upper surface of a low thermal expansion glass by lithography, and a U-shaped scale plate holder 2 surrounding the bottom surface of the scale plate 1 and the side surface in the measurement axis direction. And an attachment member 3 provided on both sides of the scale plate holder 2 and fixedly holding the scale plate holder 2 to the object to be measured 4.

  The scale plate 1 is, for example, a thin glass plate having a length ratio to thickness of 30 or more and a width ratio to thickness of 4 or more. The scale plate holder 2 is made of a low thermal expansion material such as cast iron or invar material. Since the scale plate 1 is long and thin and is easily bent by its own weight, the scale plate 1 is intended to reduce the bending of the scale plate 1 by being held and followed by the scale plate holder 2 that is more difficult to bend than the scale plate 1.

  The attachment member 3 includes a first support block 12 having a centering mechanism described later and a second support block 13. The second support block 13 includes a notch 13a on the side surface, and forms a parallel leaf spring mechanism. The attachment member 3 may be made of the same material as the scale plate holder 2 in order to make the thermal expansion coefficients of the connected scale plate holders 2 coincide.

  A method for connecting the scale plate 1 and the scale plate holder 2 will be described. The bottom surface and the side surface of the scale plate 1 are supported by the scale plate holder 2 that faces the scale plate 1 by various support members.

  First, between the bottom surface of the scale plate 1 and the upper surface (support surface) of the scale plate holder 2 is adhered by the elastic adhesive 5 at a Bessel point that is evenly spaced from the central portion in the measurement axis direction of the scale plate 1. ing. The elastic adhesive 5 is composed of three points. One of the vessel points is filled with the elastic adhesive 5e, and the other vessel point is filled with the elastic adhesive 5f via a predetermined interval in the short direction of the scale 1. And 5 g. Here, the bonding area S1 of the elastic adhesive 5e is twice the bonding area S2 of each of the elastic adhesives 5f and 5g. Further, on the upper surface of the scale plate holder 2, pins 2e, f, g on which the elastic adhesives 5 are arranged are provided as elastic adhesive seats. Here, if the scale plate 1 and the scale plate holder 2 are bonded in a state where the scale plate 1 is vertical, no excessive stress is applied to the scale plate 1.

  Second, on the side surface in the longitudinal direction of the scale plate 1, the scale plate 1 is held by the scale plate holder 2 by the abutting portion 2 d of the scale plate holder 2 and the rigid adhesive 6. An abutting portion 2d is disposed at a vessel point on one side surface of the scale plate 1. Further, a rigid adhesive 6 is disposed on both side surfaces at the center of the scale plate 1 in the longitudinal direction.

  Third, both end surfaces of the scale plate 1 in the longitudinal direction are held by the leaf springs 9. The upper end of the plate spring 9 is bonded to the scale plate 1 by the rigid bonding member 8, and the lower end is fixedly connected to the block 28 installed on the bottom surface of the scale plate holder 2 by screws 29. The block 28 is locked to the bottom surface of the scale plate holder 2 by two block fixing screws 29. The leaf spring 9 is a thin metal plate that bends to some extent in the measurement axis direction and hardly bends in the thickness direction and the width direction. A gap 2h is provided between both ends of the scale plate holder 2 and the plate spring 9 so as not to hinder the deformation of the plate spring 9 in the measurement axis direction (FIG. 6). ).

  Next, a method for connecting the scale plate holder 2 and the attachment member 3 will be described. A first support block 12 is fixed from the side surface direction by a scale plate holder fixing screw 10 at the center portion in the measurement axis direction on one side surface of the scale plate holder 2. In addition, the second support block 13 is in contact with the other side surface of the scale plate holder 2 via a butting portion 13b at the vessel point. The abutting portion 13 b is provided with a scale plate holder fixing screw 14, and the scale plate holder fixing screw 14 fixes the second support block 13 to the side surface of the scale plate holder 2.

  Then, the connection method of the attachment member 3 and the to-be-measured object 4 is demonstrated. A first support block fixing screw 15 for connecting the first support block 12 to the measurement object 4 is provided via a centering mechanism 16 at the center of the first support block 12 that is one of the attachment members 3. (FIG. 4). The alignment mechanism 16 is stopped by an upper tapered sleeve 17 having a tapered surface on the lower surface, a lower tapered sleeve 18 having a tapered surface on the upper surface so as to be engaged with the upper tapered sleeve 17, and a pin 20 on the upper portion. A hemispherical spherical seat 19 having a spherical surface is provided. Here, the upper and lower taper sleeves 17 and 18 serve to center the first support block fixing screw 15 with respect to the first support block 12, and the spherical seat 19 has a surface shape of the DUT 4. On the other hand, the mounting posture of the first support block 12 serves to give a certain degree of freedom.

  Further, the second support block 13 which is the other attachment member 3 is provided with an abutting portion 13c at the central portion in the measurement axis direction, and is in contact with the object to be measured via the abutting portion 13c. The abutting portion 13 c is provided with a second support block fixing screw 21 that fixes the second support block 13 to the DUT 4. Further, at both ends in the measurement axis direction of the second support block 13, a ball 22 that can roll, a hole holder 23 that holds the ball 22 movably on the second support block 13, and the second support block 13. An auxiliary pressing mechanism 30 having a gauge block 23 in contact with the ball 22 disposed on the bottom surface of the auxiliary pressing mechanism 30 is provided. The gauge block 23 is processed into a flat surface with high accuracy. Since the second support block 13 has a notch 13a on the side surface, the auxiliary support mechanism 30 is elastically deformed by deforming the stress that is pressed by the second support block fixing screw 21 at the central portion in the measurement axis direction. Tell with. That is, the entire member of the second support block 13 serves as a leaf spring. With this mechanism, the second support block 13 is fixed to the object 4 to be measured by the second support block fixing screw 21, and both ends press the object 4 to be measured as auxiliary pressing mechanisms 30.

  Next, the effect of the scale for a displacement measuring device configured as described above will be described.

  First, the scale plate 1 is supported by the elastic adhesive members 5e, f, and g near the lower surface vessel point, and supported by the rigid adhesive members 6 and 8 at the center of the side surface. As a result, the scale plate 1 is supported on the scale plate holder 2 at multiple points by the adhesive members 5, 6, and 8 from the side surface direction and the thickness direction. Even if it is attached, it is held by a plurality of support points, and the measurement accuracy can be made constant.

  Second, since the scale plate 1 is supported by the elastic adhesive 5 at three points, the deflection of the scale plate 1 can be held at a minimum and stably. Furthermore, since the adhesive area S1 of the elastic adhesive member 5e at one vessel point is twice the adhesive area of the elastic adhesive members 5f and g at the other vessel point, the shear stress applied from the adhesive member 5 to the scale plate 1 is Since it is symmetric with respect to the center of the scale plate 1, extra stress is not applied even if the adhesive member 5 is thermally deformed on the scale plate 1.

  Third, the side surface of the scale plate 1 is fixed to the scale plate holder 2 by applying a rigid adhesive member 6 to the scale plate holder 2 at the center in the measurement axis direction, so that no extra stress is applied in the surface direction. Can be retained. Further, by supporting the bottom surface of the scale plate 1 by the elastic adhesive members 5e, f, and g at three points, the surface direction of the scale plate 1 is determined as one surface, and the internal stress applied by the twist of the scale plate 1 is applied to the elastic adhesive. It can be absorbed by the amount of deformation.

  Fourthly, leaf springs 9 are installed on both end surfaces of the scale plate 1 and the scale plate holder 2 in the longitudinal direction, and the expansion / contraction difference in the measurement axis direction due to the difference in thermal expansion coefficient between both members can be reduced. Further, the leaf spring 9 can be displaced in the measurement axis direction, but is difficult to bend in the thickness direction and the width direction of the scale plate 1, so that the thickness direction is caused by the difference in thermal expansion between the scale plate 1 and the scale plate holder 2. In addition, there is an effect of reducing deformation in the width direction.

  Fifth, since the second support block 13 is fixedly connected to the object to be measured by the second support block fixing screw 21 and both ends are held movably in the measurement axis direction by the balls 22, The attachment member 13 can be fixedly held, and the internal stress can be released by the movement of the ball 22. Further, since the second support block 13 having the notch 13a serves as a leaf spring, the auxiliary pressing mechanism 30 can press both ends against the object 4 to be measured with a predetermined pressing force, and only at the center. The scale plate 1 can be installed by following the surface shape of the DUT 4 better than when it is fixed.

  Sixth, the attachment member 3 fixes the scale plate holder 2 to the object 4 to be measured by one second support block 13, and follows the inclination of the surface of the object 4 to be measured by the other first support block 12. Thus, the scale plate holder 2 can be held. Thereby, the measurement according to the unevenness | corrugation and inclination of the to-be-measured object 4 is attained.

  FIG. 7 is a plan view of a displacement measuring apparatus scale 200 according to the second embodiment of the present invention. 8 is a view in the direction of the arrow X2 in FIG. 7, and FIG. 9 is a view in the direction of the arrow Y2 in FIG. 10 is a cross-sectional view taken along line D-D ′ of FIG. 7, FIG. 11 is a cross-sectional view taken along line E-E ′ of FIG. 7, and FIG. 12 is a cross-sectional view taken along line F-F ′ of FIG.

  In the first embodiment, the scale plate holder 2 is held by blocks having different shapes, the first support block 12 and the second support block 13, but in the second embodiment, the support block 25 is the scale plate. It is installed on both sides of the holder 2. Similar to the first embodiment, the support block 25 includes an abutting portion 25b for the scale plate holder 2 and an abutting portion 25c for the object to be measured 4. The lead mechanism 16 and the auxiliary pressing mechanism 30 are omitted. Further, the seat of the elastic adhesive member 5 in the first embodiment is integrally formed as a protruding portion of the scale plate holder 2. Thus, even if the mechanism is simplified, the mounting structure between the scale plate 1 and the scale plate holder 2 is the same as that of the previous embodiment, and therefore the same effect can be obtained.

  FIG. 13 is a plan view of a displacement measuring device scale 300 according to the third embodiment of the present invention. 14 is a cross-sectional view taken along line G-G ′ of FIG. 13, and FIG. 15 is a cross-sectional view taken along line H-H ′ of FIG. 13.

  In this embodiment, similarly to the second embodiment, the scale plate holder 2 is attached to the DUT 4 by the support block 25. Further, the plate springs 9 as in the first and second embodiments are not provided at both ends of the scale plate 1, and instead, an elastic adhesive member 26 is further provided on the bottom surface of the scale plate 1. Yes. Further, an elastic adhesive member 27 is provided on the side surface of the scale plate 1. Thus, by holding the scale plate 1 with many adhesive members, the long scale plate 1 can be stably held on the scale plate holder 2.

  FIG. 16 is a plan view of a displacement measuring apparatus scale 400 according to the fourth embodiment of the present invention. 17 is a view in the direction of the arrow X3 in FIG. 16, and FIG. 18 is a view in the direction of the arrow Y3 in FIG.

  In the fourth embodiment, similarly to the second embodiment, the scale plate holder 2 is attached to the object to be measured 4 by the support block 25 ′. The support block 25 ′ according to the fourth embodiment has substantially the same configuration as the support block 25 according to the second embodiment. A different configuration of the support block 25 ′ from the support block 25 is a configuration of a notch portion 25 a ′ and a pair of butting portions 25 b ′ (fixed portions) to the scale plate holder 2. Note that the abutting portion 25c 'to the DUT 4 has the same shape as the abutting portion 25c of the second embodiment.

  The notch 25a 'is formed at a position that is separated from the second support block fixing screw 21 by an equal distance in the measurement axis direction. More specifically, the notch 25a 'is formed at a position away from the Bessel point of the scale plate 1 in the measurement axis method direction as viewed from the second support block fixing screw 21 in the measurement axis direction. Further, the cutout portion 25 a ′ is formed to have an equal length from the upper surface of the support block 25 ′ and the lower surface corresponding to the upper surface so as to extend along the normal direction of the scale plate 1. Further, as shown in FIG. 17, the end in the depth direction of the notch 25a ′ is formed to be an arcuate end 25T ′ having a diameter larger than the width of the other part (trunk). ing. In other words, when viewed from the side surface of the support block 25 ′, the cutout portion 25 a ′ has a shape in which the end portion 25 T ′ swells like a match rod. An elastic hinge portion is formed in the support block 25 ′ by the cutout portion 25 a ′ having such a shape, and the support block 25 ′ has flexibility.

  The abutting portion 25 b ′ is in contact with the side wall of the scale plate holder 2 and fixes the scale plate holder 2 and the support block 25 ′ with the scale plate holder fixing screw 14 (fixing portion). The abutting portion 25b 'is provided at a position away from the notch portion 25a' (elastic hinge portion) by a predetermined amount in the measurement axis direction when viewed from the second support block fixing screw 21.

  Next, an effect brought about by the structure of the displacement measuring device scale 400 according to the fourth embodiment of the present invention will be described. The description will be made with attention paid to the relationship between the scale plate 1 and the support block 25 '.

  The shapes of the support block 25 ′ and the scale plate 1 are bent by gravity. The support block 25 ′ has its own weight and the weight of the scale plate 1 received by the point supporting the scale plate 1 (the Bessel point, the point corresponding to the abutting portion 25b ′) with the second support block fixing screw 21 as an axis. To bend by receiving moment force. On the other hand, the scale plate 1 is bent by receiving the moment force due to its own weight and the bending of the support block 25 ′, with the point supporting the scale plate 1 (the Bessel point, the point corresponding to the abutting portion 25 b ′) as an axis. That is, the deflection of the support block 25 ′ and the deflection of the scale plate 1 influence each other.

  Here, when the distance between the abutting portions 25b 'is equal to the distance between the vessel points, the scale plate 1 is greatly bent into a convex shape. Therefore, in the displacement measuring apparatus scale 400 according to the fourth embodiment, the scale plate 1 is bent into an M shape by making the distance between the abutment portions 25b ′ larger than the distance between the vessel points by a predetermined amount. The amount of deflection is minimized. Such a distance between the abutting portions 25b 'is verified by FEM analysis.

It is a top view of the scale for displacement measuring devices concerning a 1st embodiment of the present invention. It is a X1 direction arrow line view of FIG. It is a Y1 direction arrow directional view of FIG. It is A-A 'sectional drawing of FIG. It is B-B 'sectional drawing of FIG. It is C-C 'sectional drawing of FIG. It is a top view of the scale for displacement measuring devices which concerns on the 2nd Embodiment of this invention. FIG. 8 is a view in the direction of an arrow X2 in FIG. 7. It is a Y2 direction arrow line view of FIG. It is D-D 'sectional drawing of FIG. It is E-E 'sectional drawing of FIG. It is F-F 'sectional drawing of FIG. It is a top view of the scale for displacement measuring devices which concerns on the 3rd Embodiment of this invention. It is G-G 'sectional drawing of FIG. It is H-H 'sectional drawing of FIG. It is a top view of the scale for displacement measuring devices concerning a 4th embodiment of the present invention. It is a X3 direction arrow line view of FIG. It is a Y3 direction arrow line view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Scale plate, 2 ... Scale plate holder, 3 ... Mounting member, 4 ... Object to be measured, 5, 26, 27 ... Elastic adhesive member, 6, 8 ... Rigid adhesive member, 9 ... Plate spring, 10 ... Scale plate holder Fixing screw, 11 ... leaf spring fixing screw, 12 ... first support block, 13 ... second support block, 14 ... scale plate holder fixing screw, 15 ... mounting member fixing screw, 16 ... alignment mechanism, 17 ... upper side Tapered sleeve, 18 ... lower tapered sleeve, 19 ... spherical seat, 20 ... pin, 21 ... second support block fixing screw, 22 ... ball, 23 ... gauge block, 24 ... ball holder, 25, 25 '... support block 28 ... Block, 29 ... Block fixing screw, 30 ... Auxiliary presser mechanism.

Claims (5)

A scale plate with a scale extending in the measurement axis direction;
A scale plate holder that has a support surface facing the bottom surface of the scale plate and two support walls facing both side surfaces of the scale plate, and supports the scale plate;
A rigid adhesive member for adhering the side surface of the central portion of the scale plate in the measurement axis direction and the support wall;
An elastic adhesive member that adheres the bottom surface of the scale plate and the support surface at a position that is substantially evenly separated in the measurement axis direction from the center in the measurement axis direction;
A scale for a displacement measuring device, comprising: an attachment member for fixing the scale plate holder to an object to be measured. The elastic adhesive member includes a first elastic adhesive member disposed at one vessel point in the measurement axis direction of the scale plate, and a second elastic member disposed at the other vessel point in a short direction via a predetermined gap. And 3 elastic adhesive members,
The scale for a displacement measuring device according to claim 1, wherein an adhesive area of the first elastic adhesive member is twice an adhesive area of the second and third elastic adhesive members.   The scale plate holder has a pair of abutting portions that abut against the side surface of the scale plate on one support wall, corresponding to the Bessel point position of the scale plate evenly from the center of the scale plate in the measurement axis direction. The scale for a displacement measuring device according to claim 1.   The scale for a displacement measuring device according to claim 1, wherein the scale plate and the scale plate holder are elastically supported by plate springs at both ends in the measurement axis direction. The scale for a displacement measuring device according to claim 1, further comprising an elastic adhesive that bonds the side surface of the scale plate and the support wall at both ends of the scale plate in the measurement axis direction .

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