JP2013007718A - Glass scale holding structure, and method for holding glass scale - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and stably hold a glass scale by appropriate structure while allowing attachment and detachment by avoiding increase of attachment dimensions of the glass scale.SOLUTION: Glass scale holding structure includes: a metal thin plate 112 which is molded with width W1 narrower than width W2 of a glass scale 116 and as longer than length L2 of the glass scale 116 in the measurement axis direction (X direction), and fixes the glass scale 116 at a state that ends 112A project from both ends of the glass scale 116 in the measurement axis direction, respectively; and through holes 112B and a screw 118 which are provided to the ends 112A, respectively, and make an object SJ attachably/detachably hold the metal thin plate 112. When the metal thin plate 112 is held to the object SJ, tension force is given to the metal thin plate 112 by screwing of the screw 118 into a screw hole of the object SJ, and the whole surface of the back face of the metal thin plate 112 is brought into contact with the object SJ.

Description

  The present invention relates to a glass scale holding structure and a method for holding a glass scale, and in particular, avoids an increase in the mounting size of the glass scale for holding the glass scale on an object and has a corresponding structure while enabling desorption. The present invention relates to a glass scale holding structure capable of easily and stably holding a glass scale, and a glass scale holding method.

  Conventionally, a leaf spring SP having one end fixed to the surface of an object SJ (scale holder) is used to hold the glass scale 16 used in a linear encoder or the like, as shown in FIG. For this reason, it is possible to easily hold the glass scale 16 on the object SJ. Further, since the glass scale 16 is held only by the pressing force of the leaf spring SP, even if a thermal stress is generated on the glass scale 16 or the object SJ, the leaf spring SP does not interfere with the strain caused by the thermal stress. It is possible to escape easily. However, in order to hold the glass scale 16 as shown in FIG. 5, it is necessary to provide a mounting dimension having a width W3 wider than the width W2 of the glass scale 16 on the object SJ. That is, in the structure shown in FIG. 5, even if the glass scale 16 is small, there arises a problem that the mounting dimension becomes large.

  Therefore, in order to reduce the mounting dimension, it is conceivable to apply a holding structure for the scale 66 shown in FIG. 6 (Patent Document 1). In Patent Document 1, a scale 66 is fixed to a metal tape 62 with a strong adhesive 64, and the metal tape 62 is attached to an object SJ with a double-sided tape 68.

JP 2004-325207 A

  However, the technique of Patent Document 1 is stable by controlling the expansion of the scale 66 by the linear expansion coefficient of the metal tape 62 when a printed wiring board having low stability with respect to changes in ambient temperature and humidity is used for the scale 66. It is for making it happen. That is, when the scale 66 is originally a glass scale, since the scale itself is highly stable, the structure shown in FIG. 6 has no meaning because it simply complicates the scale holding structure. I can't think of it.

  Therefore, in order to simplify the scale holding structure, it is conceivable to attach the glass scale directly to the object with a double-sided tape. However, in this case, if a glass scale sticking error occurs, when the glass scale is thin and the double-sided tape is strong, it is difficult to peel off the glass scale even if it is re-applied, which may damage the worst glass scale. Come out.

  The present invention has been made to solve the above-mentioned conventional problems, avoids an increase in the mounting size of the glass scale for holding the glass scale on the object, and allows easy attachment and detachment with a corresponding structure. It is another object of the present invention to provide a glass scale holding structure capable of stably holding a glass scale, and a glass scale holding method.

  The invention according to claim 1 of the present application is a glass scale holding structure for holding a glass scale on an object, and is formed with a width equal to or smaller than the width of the glass scale and longer than the length in the measurement axis direction of the glass scale, A thin metal plate for fixing the glass scale in a state where the end portions of the glass scale protrude from both ends in the measurement axis direction, and a protruding end portion of the thin metal plate, respectively, A fixing mechanism for holding the metal thin plate in a detachable manner, and when the metal thin plate is held by the object, a tension in the measurement axis direction is applied to the metal thin plate by the fixing mechanism. And the said subject is solved by making the back surface except the edge part which this metal thin plate protruded contact | abutted with this target object in one or more places.

  In the invention according to claim 2 of the present application, an elastic layer is further provided between the glass scale and the metal thin plate.

  In the invention according to claim 3 of the present application, the fixing mechanism provided on at least one protruding end of the metal thin plate includes an inclined surface inclined with respect to the measurement axis direction and is fixed to the object. And a moving member that can be moved and fixed along the inclined surface while being screwed to the fixing member and is fixed to the protruding end of the thin metal plate. It is what I did.

  In the invention according to claim 4 of the present application, the thickness of at least one end portion in the width direction of the metal thin plate is made larger than the thickness of the central portion in the width direction of the metal thin plate.

  The invention according to claim 5 of the present application is a glass scale holding method for holding a glass scale on an object, and is formed with a width equal to or smaller than the width of the glass scale and longer than the length of the glass scale in the measurement axis direction. A step of preparing a thin metal plate to which the glass scale is fixed in a state in which the end portions of the glass scale protrude from both ends of the measurement axis direction, and one protruding end portion of the thin metal plate is the target. Attaching the object to the object in a detachable manner, applying tension to the metal sheet in the direction of the measurement axis, and the back surface excluding the protruding end of the metal sheet is brought into contact with the object at one or more points. And attaching the other protruding end of the metal sheet to the object in a detachable manner.

  According to the present invention, it is possible to easily and stably hold a glass scale with a corresponding structure while avoiding an increase in the mounting size of the glass scale for holding the glass scale on an object and enabling desorption. It becomes.

1 is a schematic perspective view of a linear encoder according to a first embodiment of the present invention. Similarly, schematic diagram of glass scale holding structure (top view (A), side view (B)) Schematic schematic diagram of the glass scale holding structure according to the second embodiment of the present invention. Schematic diagrams (A) and (B) showing the shapes of the respective thin metal plates according to the first and third embodiments of the present invention. Schematic diagram showing conventional technology for holding glass scales with leaf springs Schematic diagram showing conventional technology that maintains an unstable scale in temperature and humidity

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

  First, the configuration of the linear encoder according to the first embodiment will be described mainly with reference to FIGS.

  The linear encoder 100 is a photoelectric type, and includes a glass scale 116 and a detection head 138 as shown in FIG. For this reason, in the linear encoder 100, light emitted from a light source (not shown) built in the detection head 138 is modulated by the optical grating formed on the glass scale 116, and the modulated light is detected by the detection head 138. It is detected by a light receiving element (not shown) built in the. The displacement in the measurement axis direction (X direction) of the glass scale 116 relative to the detection head 138 is obtained from the detected light.

  As shown in FIGS. 2A and 2B, the glass scale 116 has a width W2 (length in the Y direction), a length L2 in the measurement axis direction (X direction), and a thickness T3 (length in the Z direction). It has. Specifically, in this embodiment, the thickness T3 is 1 to 5 mm, and the length L2 is 1 m or less. The material of the glass scale 116 is made of glass for general use, but may be low expansion glass having zero expansion characteristics over a wide temperature range and high thermal shock resistance.

  As shown in FIG. 2B, the glass scale 116 is bonded and fixed to the metal thin plate 112 with an elastic layer 114 (thickness T2) formed of an elastic adhesive (the elastic layer is fixed by fixing with a double-sided tape). May be molded). In the present embodiment, the thickness T2 is 0.2 to 0.5 mm. The thin metal plate 112 has an elongated tape shape, and its width W1 is narrower than the width W2 of the glass scale 116, and its length L1 is longer than the length L2 of the glass scale 116 in the measurement axis direction. In the present embodiment, the metal thin plate 112 is made of, for example, iron or aluminum. Further, since the thickness T1 of the metal thin plate 112 is 1 mm or less, the metal thin plate 112 can be easily cut and formed.

  2A and 2B, the thin metal plate 112 fixes the glass scale 116 with the end portions 112A protruding from both ends of the glass scale 116 in the measurement axis direction. Each protruding end 112A is formed with a through hole 112B. The male screw portion 118A of the screw 118 passes through the two through holes 112B, the male screw portions 118A are respectively screwed into the screw holes formed in the object SJ, and the metal thin plate 112 is held by the object SJ. That is, the through hole 112B and the screw 118 are provided at the protruding end portion 112A of the thin metal plate 112, respectively, and have a function as a fixing mechanism that holds the thin metal plate 112 so as to be detachable from the object SJ. The interval between the two screw holes of the object SJ is larger than the interval between the two through holes 112B so that when the screw 118 is screwed into the screw hole, a tension in the measurement axis direction is applied to the metal thin plate 112. Has also been long. The surface of the object SJ between the two screw holes is flat. For this reason, when the metal thin plate 112 is held by the object SJ, the entire back surface of the metal thin plate 112 comes into contact with the object SJ in the measurement axis direction.

  Next, a procedure for holding the glass scale 116 on the object SJ will be described with reference to FIGS.

  First, the metal thin plate 112 to which the glass scale 116 is fixed is prepared. Here, the width W 1 of the thin metal plate 112 is narrower than the width W 2 of the glass scale 116. Therefore, positioning for bonding and fixing the thin metal plate 112 to the glass scale 116 (positioning so that the thin metal plate 112 does not protrude from the width W2 of the glass scale 116) can be easily performed.

  Next, one protruding end 112A of the thin metal plate 112 is detachably attached to the object SJ. That is, the male screw portion 118A of the first screw 118 is passed through the through hole 112B of one end portion 112A of the thin metal plate 112, and the male screw portion 118A is screwed into one of the screw holes formed in the object SJ. Combine.

  Next, a tension is applied to the thin metal plate 112 in the measurement axis direction, and the other protruding end 112A of the thin metal plate 112 is targeted so that the entire back surface of the thin metal plate 112 contacts the object SJ. It is attached to the object SJ so as to be removable. That is, the male screw portion 118A of the second screw 118 is passed through the through hole 112B of the other end portion 112A of the thin metal plate 112, and the male screw portion 118A is inserted into another screw hole formed in the object SJ. Screw together. At this time, the interval between the two screw holes of the object SJ is such that the two through holes 112B are provided so as to appropriately apply the tension in the measurement axis direction to the metal thin plate 112 when the screw 118 is screwed into the screw hole. (This appropriate tension can be a force that does not cause plastic deformation of the thin metal plate 112). For this reason, when the second screw 118 is screwed into the screw hole and comes into contact with the object SJ on the entire back surface of the thin metal plate 112, the tension in the measurement axis direction is applied to the thin metal plate 112. It is given in a stable state.

  In the prior art shown in FIG. 5, the mounting dimension W3 is increased as compared with the width W2 of the glass scale 16 by using the leaf spring SP as described above. In addition, the tap TP for fixing the leaf spring SP to the object SJ needs to be processed into the object SJ over the entire length of the glass scale 16 at a constant interval (for example, 75 to 100 mm). In order to hold the object SJ on the object SJ, the processing load is large, which is a factor of cost increase.

  On the other hand, as described above, in the present embodiment, the thin metal plate 112 is formed to have a width W1 narrower than the width W2 of the glass scale 116 and longer than the length L2 of the glass scale 116 in the measurement axis direction. And the glass scale 116 is being fixed in the state in which the end part 112A protruded from the both ends of the measurement axis direction of the glass scale 116 at the metal thin plate 112, respectively. For this reason, the glass scale 116 can be held on the object SJ without increasing the mounting dimension in the width direction (Y direction) of the glass scale 116.

  At the same time, in this embodiment, a glass scale 116 having a thickness T3 of 1 to 5 mm is fixed to a thin metal plate 112 having a thickness T1 of 1 mm or less via an elastic layer 114 having a thickness T2 of 0.2 to 0.5 mm. Yes. That is, the thickness of the holding structure of the glass scale 116 (excluding the thickness T3 of the glass scale 116) can be made thinner than the thickness T3 of the glass scale 116.

  Here, in the holding structure of the scale 66 of Patent Document 1, as shown in FIG. 6, the metal tape 62, the strong adhesive 64, and the double-sided tape 68 are interposed between the object SJ and the scale 66. In Patent Document 1, the metal tape 62 needs to have an appropriate thickness, that is, at least the same as the thickness of the scale 66 because the expansion rate of the scale 66 is controlled by the metal tape 62. On the other hand, in the present embodiment, the metal thin plate 112 does not need to have such a function and can be thinned, and the mounting dimension can be increased from the viewpoint of thickness compared to the holding structure of the scale 66 of Patent Document 1. It can be avoided and miniaturized.

  And in this embodiment, the screw | thread 118 is penetrated to the through-hole 112B each provided in the edge part 112A of the metal thin plate 112, and the screw | thread 118 is each screwed by the screw hole of the target object SJ. For this reason, the metal thin plate 112 can be easily detached from the object SJ, and the glass scale 116 can be easily held again on the object SJ without damaging the glass scale 116. For this reason, the position of the glass scale 116 can be adjusted.

  Furthermore, in the present embodiment, when the metal thin plate 112 is held by the object SJ, a tension in the measurement axis direction is applied to the metal thin plate 112 by screwing into the screw hole of the screw 118, and The entire back surface of the metal thin plate 112 is brought into contact with the object SJ. For this reason, it is possible to prevent the glass scale 116 from resonating due to disturbance (vibration) (the glass scale 116 behaving like a wave). Note that the application of tension to the metal thin plate 112 does not depend on the precise processing accuracy between the interval between the screw holes of the object SJ and the interval between the two through holes 112B, and the metal thin plate 112 is simply measured with another member as a measurement axis. The thin metal plate 112 may be fixed to the object SJ with the screw 118 while being pulled in the direction.

  In the present embodiment, the glass scale 116 is held by screwing the two screws 118 into the screw holes of the object SJ. That is, the processing load on the object SJ is less than that of the prior art shown in FIG. 5, and the glass scale 116 can be held by a very simple means at a low cost.

  In the present embodiment, an elastic layer 114 is further provided between the glass scale 116 and the metal thin plate 112. For this reason, even if the tension applied to the metal thin plate 112 is large and a large strain occurs in the metal thin plate 112, the strain can be prevented from being transmitted to the glass scale 116.

  Therefore, according to the present embodiment, an increase in the mounting dimension of the glass scale 116 for holding the glass scale 116 on the object SJ is avoided, and the glass scale can be easily and stably provided with a corresponding structure while being able to be detached. 116 can be held. For this reason, in this embodiment, when the size of a glass scale is made small, it becomes possible to remarkably utilize the size merit (characteristics of lightness, shortness, and smallness) of the glass scale.

  Although the present invention has been described with reference to the first embodiment, the present invention is not limited to the first embodiment. That is, it goes without saying that improvements and design changes can be made without departing from the scope of the present invention.

  For example, in the first embodiment, the function of the fixing mechanism is exhibited by the through hole 112B and the screw 118 (and the screw hole of the object SJ), but the present invention is not limited to this. For example, the second embodiment shown in FIGS. 3A and 3B may be used. Here, the fixing mechanism 220 different from the first embodiment will be described, and the other description will be omitted to avoid duplication.

  In the second embodiment, as shown in FIGS. 3A and 3B, the fixing mechanism 220 provided at one end 212 </ b> A of the thin metal plate 212 includes a fixing member 222 and a moving member 224. In the fixing member 222, a recess 222A is provided on the side opposite to the thin metal plate, and an inclined surface 222B that is inclined with respect to the measurement axis direction is formed by forming the recess 222A. A screw hole 222D is formed in the recess 222A substantially parallel to the inclined surface 222B. A through hole 222C is formed in the portion of the fixing member 222 where the concave portion 222A is not formed, and a screw 226 engages with the through hole 222C, and the fixing member 222 is fixed to the concave portion PT formed in the object SJ. Is done.

  On the other hand, in the moving member 224, a recess 224A is provided on the metal thin plate side, and an inclined surface 224B that is inclined with respect to the measurement axis direction is formed by forming the recess 224A. The inclined surfaces 222B and 224B have the same inclination angle and are in contact with each other. And in the recessed part 222A, the edge part 212A of the metal thin plate 212 is being fixed. And the through-hole 224C is shape | molded in the part of the moving member 224 in which the recessed part 224A is not shape | molded substantially parallel to the inclined surface 224B. The screw 228 engages with the through hole 224C, and the screw 228 can be moved and fixed along the inclined surface 222B of the moving member 224 while being screwed into the fixing member 222 (the screw hole 222D thereof). . A through hole is formed in the other end 212A of the thin metal plate 212 as in the first embodiment, and the end 212A is attached to the object SJ with a screw 218.

  When the glass scale 216 is held on the object SJ, one end 212A of the thin metal plate 212 is attached with the screw 218 as in the first embodiment. Then, after the fixing member 222 of the fixing mechanism 220 is attached to the object SJ, the moving member 224 fixed to the other end 212 </ b> A of the metal thin plate 212 is fixed to the fixing member 222 with the screw 228. Note that, as shown in FIG. 3B, the shape of the recess PT is configured to contact the object SJ on the entire back surface of the metal thin plate 212 at this time.

  For this reason, in the present embodiment, unlike the first embodiment, it is possible to easily and stably apply tension to the thin metal plate 212 without being affected by the accuracy of the screw hole interval of the object SJ. In the present embodiment, the fixing mechanism 220 is applied only to the one end 212A, but may be applied to both ends of the thin metal plate. Further, the fixing mechanism 220 may be provided with a tapered shape on the inclined surface in one or two axes, for example, so that the positioning in the one or two axes may be performed simultaneously when the glass scale 216 is held.

  Or the structure which does not use a screw may be sufficient as a fixing mechanism. For example, an extendable hook-shaped member is provided at one end of the thin metal plate, and a through-hole through which a pin can be fitted is provided at the other end. The object SJ is provided with a first recess that can be engaged by the hook-shaped member and a second recess that can be fitted with the pin. When holding the glass scale on the object SJ, the hook-shaped member is engaged with the first recess of the object SJ, and then the pin is inserted into the through hole of the metal thin plate and the second recess of the object SJ. You may make it fit (an order may be reverse). At that time, it is possible to apply tension to the metal thin plate by the expansion and contraction of the hook-shaped member.

  In the first embodiment, the thickness of the thin metal plate 112 is uniform in the width direction (Y direction) as shown in FIG. 4A, but the present invention is not limited to this. For example, it may be as in the third embodiment shown in FIG. Here, the metal thin plate 312 that is different from the first embodiment will be described, and other descriptions will be omitted to avoid duplication.

  In the third embodiment, the thickness of both end portions in the width direction (Y direction) of the thin metal plate 312 is thicker than the thickness of the central portion in the width direction of the thin metal plate 312 (even in this case, the thickness T1 thereof). Is 1 mm or less). For this reason, the thin metal plate 312 has high rigidity and is less likely to bend than the thin metal plate 112 of the first embodiment.

  Therefore, in this embodiment, the disturbance (vibration) transmitted to the glass scale 316 can be further reduced. In the present embodiment, the portion 312C that is thicker than the central portion of the thin metal plate 312 may be formed at the beginning of the formation of the thin metal plate 312. Alternatively, the end in the width direction may be bent at 90 degrees from the original thin metal plate with uniform thickness, or may be completely folded back. Further, in the present embodiment, the thickness of both end portions in the width direction of the thin metal plate 312 is thicker than the thickness of the central portion in the width direction of the thin metal plate 312, but only one of the end portions is the central portion. It may be thicker than the thickness.

  Moreover, in the said embodiment, although the width W1 of the metal thin plate was made narrower than the width W2 of a glass scale, the width W1 should just be below the width W2.

  Moreover, in the said embodiment, although it contact | abutted to the target object and was hold | maintained at the target object SJ in the whole back surface of the metal thin plate, this invention is not limited to this. It is only necessary that the back surface of the thin metal plate except the protruding end is in contact with the object at one or more places, and even at that time, it is possible to appropriately prevent the thin metal plate from resonating due to disturbance (vibration). .

  Moreover, in the said embodiment, although the elastic layer was further provided between the glass scale and the metal thin plate, this invention is not limited to this, There is no elastic layer, for example, a glass scale and a metal thin plate May be fixed with a strong adhesive.

  In the above embodiment, only two fixing mechanisms are used to hold the metal thin plate on the object, but the present invention is not limited to this. For example, when the thin metal plate is held on the object, a fixing auxiliary means that is difficult by itself may be used in combination with the fixing mechanism. As a fixing method using the fixing auxiliary means, for example, at least one portion where the back surface of the metal thin plate between the two fixing mechanisms is in contact with the object is bonded with a bonding amount of an instantaneous adhesive that can be removed by a light impact. Can be used.

  In the above embodiment, the photoelectric linear encoder is used. However, the present invention is not limited to this, and may be an electromagnetic induction type, a magnetic type, or the like, and a glass scale may be used.

  The present invention is particularly applicable to a linear encoder having a glass scale.

16, 116, 216, 316 ... glass scale 62 ... metal tape 64 ... strong adhesive 66 ... scale 68 ... double-sided tape 100 ... linear encoder 112, 212, 312 ... metal thin plate 112A, 212A ... end 114, 214, 314 ... Elastic layer 118, 218, 226, 228 ... Screw 138 ... Detection head 220 ... Fixing mechanism 222 ... Fixing member 224 ... Moving member

Claims (5)

In the glass scale holding structure that holds the glass scale on the object,
The glass scale is formed with a width equal to or less than the width of the glass scale and longer than the length in the measurement axis direction of the glass scale, and the ends of the glass scale projecting from both ends in the measurement axis direction. With metal sheet to fix,
A fixing mechanism that is provided at each protruding end of the thin metal plate and holds the thin metal plate so as to be detachable from the object,
When the metal thin plate is held by the object, the fixing mechanism applies tension in the measurement axis direction to the metal thin plate, and the back surface excluding the protruding end of the metal thin plate is uniform. A glass scale holding structure which is brought into contact with the object at more than one place.   The glass scale holding structure according to claim 1, wherein an elastic layer is further provided between the glass scale and the metal thin plate.   The fixing mechanism provided at at least one protruding end of the thin metal plate has an inclined surface that is inclined with respect to the measurement axis direction, and is fixed to the object, and the fixing member of the screw 3. A moving member that can be moved and fixed along the inclined surface in a screwed state, and is fixed to a protruding end of the thin metal plate. The glass scale holding structure as described.   The glass according to any one of claims 1 to 3, wherein a thickness of at least one end portion in the width direction of the thin metal plate is thicker than a thickness of a central portion in the width direction of the thin metal plate. Scale retention structure. In the glass scale holding method for holding the glass scale on the object,
The glass scale is formed with a width equal to or less than the width of the glass scale and longer than the length in the measurement axis direction of the glass scale, and the ends of the glass scale projecting from both ends in the measurement axis direction. A step of preparing a thin metal plate fixed with
Attaching one projecting end of the metal sheet to the object in a detachable manner;
The thin metal sheet is tensioned in the direction of the measuring axis, and the back surface of the thin metal sheet excluding the protruding end is in contact with the object at one or more locations. Attaching one protruding end to the object in a detachable manner;
A method for holding a glass scale, comprising:

Images