JP2002013924A - Scale holding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a scale from slipping off a scale holder due to external vibration, etc., while allowing thermal expansion displacement generated in the measurement axis direction between the scale holder and the scale. SOLUTION: The scale 2 is a rectangular solid made of glass and has the measurement axis in its length direction. The scale holder 1 is an aluminum extrusion molding and has a groove 11 in the direction of the measurement axis X. A frictional force increasing mechanism 6 is formed on at least one surface, confronting a side face of the groove 11, of a side end part of the scale 2 inserted into the groove 11. The width of the groove 11 is larger than the thickness of the scale 1, and a plurality of elastic members 7a are inserted at prescribed intervals between the mechanism 6 on the surface of the scale 2 inserted in the groove 11 and the side face of the groove 11. The elastic members 7a permit relative displacement between the scale 2 and the scale holder 1 in the axis direction (x-axis direction) while suppress displacement in a scale plane in a direction (z-axis direction) normal to the axis x.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
Displacement detection device equipped with a linear scale held by a scale holder that has a shield function to prevent oil and the like from entering, and a detector that obtains displacement information while contacting this scale (hereinafter referred to as a shield type linear scale) And a scale holding mechanism.

[0002]

2. Description of the Related Art A shield type linear scale is known as a measuring device used for detecting a displacement of a table of a machine tool or the like. The scale is provided with a scale holder having both a shield function for preventing intrusion of dust and oil from the outside and a scale holding function by a groove provided inside. Generally, an extruded aluminum material is used for this scale holder, and the material of the linear scale held by the holder is often glass. In a device that combines materials having such different linear expansion coefficients, when a temperature change occurs in the device itself, a difference occurs in the amount of thermal expansion between the two members. This difference causes a thermal stress between the scale holder and the scale. Occurs. As a result, measurement accuracy may be degraded. Also, the direction of the thermal stress differs between when the temperature rises and when the temperature falls, and the measurement accuracy may change due to the temperature change history due to the occurrence of the residual stress. In order to reduce the influence of the hysteresis difference of the thermal expansion displacement between the scale and the scale holder, it is necessary to allow the relative displacement between the scale and the scale holder and to slide the contact surface between both members to some extent.

[0003] One end of the scale is held in a cantilever manner, and a detector is attached to the other end. Due to such a holding structure, the scale may receive inertial force due to external vibration in various directions on a plane perpendicular to the measurement axis, for example, with an acceleration of 100 to 200 m / s ² , and the holding force of the scale is weak. The scale may easily come off from the groove of the scale holder. Further, it is difficult to firmly hold a scale often made of glass by a scale holder made of aluminum. It is possible to address these problems by devising the shape of the scale and scale holder.However, it is costly to process materials that are not easily molded, such as glass, with high precision for each product. Is not preferred. Therefore, while maintaining a structure that is easy to mold like a conventional scale and scale holder, the expansion displacement in the measurement axis direction of the scale due to a temperature change of the device is not restricted, and the scale detaches from the groove due to external vibration or the like. Therefore, a means for satisfying the demand for preventing such a situation is required.

To solve this problem, conventionally, for example,
As shown in FIG. 1A, a method of inserting a glass scale 2 into a groove 11 of an aluminum scale holder 1 and then inserting a cylindrical rubber 3 between the groove 11 and the scale 2 has been used. The cylindrical rubber 3 presses and holds the scale against the measurement surface of the groove 11 by the elastic force generated in the y-axis direction. In order to stably hold the scale against external vibrations and to prevent detachment in the z-axis direction, it is necessary to increase the elastic force of the cylindrical rubber 3. Avoidance of thermal stress becomes insufficient due to excessive frictional force generated between the scale and the scale. However, when the elastic force of the cylindrical rubber 3 is weakened to avoid thermal stress, the holding force alone is weak against large external vibrations, and the scale 2 is
From the camera in the z-axis direction. Therefore, the elastic adhesive 4
(Fluid silicone rubber adhesive) is added to the cylindrical rubber 3 to join the side surfaces of the groove 11 and the cylindrical rubber 3 and the cylindrical rubber 3 and the side surface of the scale 2 to increase the holding force. There is a way to increase it. However, in this method, when the scale 2 is arranged in the groove 11, the scale 2 and the groove 11
The elastic adhesive 4 wraps around the side surfaces of the scale 2 and restricts the thermal displacement of the scale 2 in the x-axis (measurement axis) direction, which results in the occurrence of defective thermal stress due to thermal expansion. Here, the elastic adhesive 4
Is changed to a silicone rubber adhesive having no fluidity, the adhesive can be prevented from flowing between the groove 11 and the scale 2, but the holding in the y-axis direction is not sufficient. In addition, there is a problem that the elastic force of rubber changes with time (creep phenomenon), and the reliability is low in terms of stable holding force. In addition,
Although a U-shaped leaf spring is used as a means for generating a force in the y-axis direction for pressing the scale 2 against the side surface of the groove 11, the above problem has not been sufficiently solved.
FIG. 1B shows a method of joining the side surfaces of a glass scale to an aluminum scale holder with a thick elastic adhesive 5. According to this method, the difference in thermal expansion displacement between the scale holder 1 and the scale 2 can be absorbed by the elastic deformation of the elastic adhesive 5. In addition to this holding structure, a structure has also been proposed in which a leaf spring is inserted into the gap between the scale 2 and the groove 11 on the opposite side of the elastic adhesive 5 (Japanese Patent Laid-Open No. 8-43068). However, the control of the shearing force of the elastic adhesive 5 is difficult, and the flatness cannot be set based on the side surface of the groove 11 of the scale holder 1 when the scale is bonded, so that the bonding process is difficult, and the scale 2 is scanned as a guide. Yz generated by the pressing force of the detector
There is a problem that the moment M on the plane is weak.

[0005]

As described above, external vibrations (moment M in FIG. 1, etc.) are absorbed while absorbing the thermal expansion displacement difference in the measurement axis (x-axis in FIG. 1) direction between the scale holder and the scale. It is difficult to realize a holding mechanism capable of withstanding by a simple mechanism, and a sufficient holding mechanism has not been provided yet.

The present invention has been made in view of such a problem, and has a sufficient holding force to withstand external vibration while allowing a difference in thermal expansion displacement between a scale and a scale holder in a measurement axis direction. It is an object of the present invention to provide a scale holding mechanism that can be realized easily.

[0007]

A scale holding mechanism according to the present invention comprises: a scale having a measuring axis in a longitudinal direction; a scale holder having a groove for holding the scale at one end thereof; A frictional force increasing mechanism formed on at least one surface facing the first side surface of the groove;
It is inserted and disposed in the gap between the frictional force increasing mechanism of the scale and the first side surface of the groove, and allows relative displacement in the measurement axis direction between the scale and the scale holder,
An elastic member that suppresses relative displacement in a direction orthogonal to the measurement axis within the plane of the scale and generates a force that presses the scale toward the second side surface of the groove. .

According to the present invention, it is possible to prevent the scale from being detached from the scale holder due to external vibration or the like, while allowing thermal expansion displacement in the measurement axis direction between the scale holder and the scale.

It is preferable that the elastic member has a projection fixed to the frictional force increasing mechanism.

Preferably, the elastic member is made of a thin elastic material such as a metal spring material.

[0011] For example, a plurality of the elastic members can be arranged in the longitudinal direction of the scale. Further, by selecting the spring constant and the number of the elastic members, the holding force in the x and y directions of the entire scale can be adjusted.

[0012] The frictional force increasing mechanism may be formed continuously in the longitudinal direction of the scale, or may be divided into a plurality of parts in the longitudinal direction of the scale corresponding to the elastic members.

[0013] Further, it is preferable that relative displacement of the scale in the measurement axis direction with respect to the groove is restricted at one position in the longitudinal direction. In addition, the gap between the groove and the groove is adhesively fixed at one position in the longitudinal direction of the scale, and the relative displacement of the scale and the groove in the measurement axis direction is fixed at the part fixed by the adhesive layer. It is also preferred that it be regulated.

Furthermore, a frictional force reducing mechanism may be formed between the second side surface of the groove and the scale.

The frictional force increasing mechanism may be formed on the scale surface by a coating process or may be formed by machining.
In addition, the frictional force increasing mechanism can be formed by attaching a tape for increasing the frictional force.

The frictional force reducing mechanism may be formed by a coating process, or may be formed by attaching a tape for reducing the frictional force.

Further, by providing an auxiliary elastic body for pressing the scale in the direction of the second side face of the groove between adjacent elastic members, the scale holding force can be reinforced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a perspective view showing an overview of the scale holding mechanism according to the first embodiment of the present invention. The scale 2 is a rectangular parallelepiped made of glass and has a measurement axis in the longitudinal direction (the x-axis direction in the figure). The scale holder 1 is an extruded aluminum material and has a groove 11 extending in the measurement axis x direction. Scale 2
The frictional force increasing mechanism 6 is formed on at least one surface facing the side surface of the groove 11 at the side end inserted into the groove 11. The width of the groove 11 is wider than the thickness of the scale 2, and the frictional force increasing mechanism 6 on the surface of the scale 2 inserted into the groove 11
A plurality of elastic members 7a are inserted at predetermined intervals between the elastic member 7a and the side surface of the groove 11. Here, the elastic member 7a allows the relative displacement of the scale 2 and the scale holder 1 in the measurement axis direction (x-axis direction), and the displacement in the direction orthogonal to the measurement axis x (z-axis direction) in the scale plane. Suppress and scale 2
Has a structure that generates an elastic force that is pressed in the direction of the side surface (y-axis direction). Note that the relationship of the ease of deformation of the elastic member 7a in each axial direction is such that x-axis (measurement axis) direction> y-axis direction> z-axis direction.

FIG. 3A is a perspective view showing details of the elastic member 7a, and FIG. 3B is a plan view seen from the direction A in FIG. 3A. The elastic member 7a is made of a thin elastic material such as a metal leaf spring, and is capable of elastic deformation 71 in the x-axis direction and elastic deformation 72 in the y-axis direction on the xy plane, and in the z-axis direction. Has a rigid structure that is not easily deformed. Also, as can be seen from FIG.
Projections 73 and 74 are arranged in the y-axis direction at a portion in contact with the side surface of the scale 1 and a portion in contact with the frictional force increasing mechanism 6 arranged on the surface of the scale 2 in order to increase the generated frictional force. I have. It is preferable that the protrusion has a shape that can increase the frictional resistance with the contact surface. In the figure, two blades are provided as the protrusions 74, but it is preferable to provide as many blades as possible for the protrusions 74 in consideration of the posture stability at the time of contact. FIG. 4 shows an elastic member 7b provided with three projections 74.
FIG. 5 shows an elastic member 7c provided with four protrusions 74. FIG. With the elastic member having such a structure, the effect of the hysteresis difference due to the thermal expansion displacement in the x-axis, that is, the measurement axis direction when holding the scale 2 is reduced,
The displacement of the scale 2 in the z-axis direction, that is, the direction in which the scale 2 separates, is suppressed.

Instead of the elastic member shown in FIGS. 3 to 5, for example, an elastic member 7d having a curved surface as shown in FIG. 6 may be used. This elastic member 7d also has the above-mentioned elastic members 7a, 7a.
Elastic deformations 71 and 7 on the xy plane as in b and 7c
2 is possible, and the structure is hardly deformed on the zy plane and has high rigidity. Similarly, projections 73 and 74 are arranged on the elastic member 7d to increase the frictional force generated on the side surface of the groove 11 and the frictional force increasing mechanism 6. Although two projections 74 are provided in the drawing, the projections 74 are provided like an elastic member 7e provided with three projections 74 and 7f provided with four projections 74 shown in FIGS.
More stable holding is possible by increasing the number of blades.

In addition, for example, as shown in FIGS. 9 and 10, even in the case of the elastic members 7a 'and 7d' having no projection 74, the present invention can be applied to the scale holding mechanism according to the present invention.
Hereinafter, a method of fixing the elastic members 7a 'and 7d' to the side surface of the groove 11 will be described. FIG. 11A shows an elastic member 7a '.
FIG. 2B is a perspective view showing a first method of fixing the groove 11 to the side surface, and FIG. 2B is a plan view seen from the direction A in FIG.
The elastic member is fitted into a recess 12 provided on the side surface of the groove 11 to realize fixing to the side surface of the groove 11. With such a configuration, displacement of the elastic member in the x-axis (measurement axis) direction and the z-axis direction can be prevented. Next, FIG.
(A) is a perspective view showing a second method of fixing the elastic member 7a 'to the side surface of the groove 11, and (b) is a plan view viewed from the direction A in (a). As shown in the figure, the elastic member 7a 'may be bonded to the side surface of the groove 11 by disposing an adhesive 13 on the side surface of the groove 11 instead of the depression 12. As the adhesive 13, an adhesive tape or the like can be used in addition to the adhesive. With the above configuration, it is possible to prevent the displacement of the elastic member in the x-axis (measurement axis) direction and the z-axis direction. In this example, the elastic member 7
Although a ′ was used, the same fixing method can be applied to another elastic member 7 d ′ having no projection 74.

Next, details of the arrangement of the elastic member and the frictional force increasing mechanism 6 will be described. FIG. 13 (a),
(B) is a schematic view of the case where the elastic members 7a and 7d are used, respectively, observed from the direction of A in FIG. In the first arrangement method shown in FIGS. 7A and 7B, the scale 2 has a frictional force increasing mechanism 6 continuously arranged in the x-axis direction on the surface on which the elastic members 7a and 7d are arranged. The elastic members 7a, 7d
As a result, the groove 11 receives the pressing force in the y-axis direction. Further, a plurality of elastic members 7a and 7d are arranged in the x-axis direction, and the entire scale 2 is pressed against the side surface of the groove 11 by the elastic members arranged as described above.

Next, FIGS. 14A and 14B show elastic members,
And a second arrangement method of the frictional force increasing mechanism 6 is shown. This figure is also observed from the direction of A in FIG. In this example, the frictional force increasing mechanism 6 is divided so as to be disposed only around the position where the elastic members 7a and 7d contact each other. By adopting such an aspect, the arrangement area of the frictional force increasing mechanism 6 can be reduced to a necessary minimum, the labor required for disposing the frictional force increasing mechanism 6 can be reduced, and wear and peeling Even if a part of the frictional force increasing mechanism 6 does not function due to the above-mentioned factors, there is an advantage that the influence on the arranged other frictional force increasing mechanism 6 can be minimized.

FIGS. 15A and 15B show a third arrangement method which is an example in which the first arrangement method is modified. In this example, the frictional force reducing mechanism 8 is arranged on the surface of the scale 2 on the side where the elastic members 7a and 7d are not arranged. Thus, the friction force generated between the scale 2 sandwiching the frictional force reducing mechanism 8 and the side surface of the groove 11 is reduced, so that the scale 2 is slid to some extent and the scale 2 and the scale holder 1 are thermally expanded. The influence of the thermal stress due to the hysteresis difference can be reduced. As the frictional force reducing mechanism 8, for example, coating with Teflon (registered trademark) or the like on the side surface of the groove 11 or sticking of a slippery tape can be applied. Further, the frictional force reducing mechanism 8 mainly includes the scale 2
It is preferable to reduce the frictional force in the measurement axis direction generated between the groove and the side surface of the groove 11.

FIGS. 16A and 16B show a fourth arrangement method which is an example in which the second arrangement method is modified. In this example, similarly to the third arrangement method, the frictional force reducing mechanism 8 is disposed on the surface of the scale 2 on which the elastic member is not disposed. 15 and 16, the frictional force reducing mechanism 8 can be divided and arranged at predetermined intervals in the x-axis direction.

Any one of the plurality of elastic members is used as a rigid reference member having no displacement in the x-axis direction.
It is effective to regulate the relative displacement of the scale 2 and the groove 11 in the measurement axis direction. Thus, a point (the origin of thermal expansion displacement) where there is no relative displacement due to a difference in thermal expansion between the scale holder 1 and the scale 2 can be set to an appropriate position such as a longitudinal middle point or end of the scale 2. it can.
In addition, like the fifth arrangement method shown in FIG. 17, a plurality of elastic members are connected to the side surface of the scale 2 and the groove 1 similarly to the first arrangement method.
1, an adhesive layer 14 is disposed on a portion between the bottom surface of the scale 2 and the bottom surface of the groove 11 facing the bottom surface of the scale 2 to provide a portion to be bonded and fixed. It is also effective to set a reference position for restricting a relative displacement of the side surface of the groove 2 and the side surface of the groove 11 in the measurement axis direction. The size of the bonding surface of the adhesive layer 14 is such that the scale 2 is not detached from the groove 11 by the adhesive layer 14 and the elastic member even when the maximum acceleration that can be assumed in use is applied to the scale 2. May be set in consideration of the characteristics of the adhesive so that the scale 2 can be held.

The elastic members need not be independent one by one, but may have an integral structure in which the elastic members are connected to each other.

Specifically, the frictional force increasing mechanism 6 can be formed by the following method. (A) Grinding such as honing is performed on the surface of the scale 2. (B) Scale 2
Is machined so that its surface has a wavy cross section in the z-axis direction. (C) The surface of the scale 2 is coated with fine particles or the like, or is sprayed or vapor-deposited. (D) A tape or the like that increases the frictional force is attached. As the material of the tape, a fiber, a metal, a resin, an adhesive tape, or the like can be used.

FIGS. 18A and 18B show a sixth arrangement method which is another example obtained by modifying the first arrangement method. This figure is also observed from the direction of A in FIG. In this example, an auxiliary elastic body is arranged between adjacent elastic members. Specifically, a rubber ball 9a or a cylinder 9b is used as the auxiliary elastic body. As the rubber, non-fluid silicone rubber, natural rubber, synthetic rubber, or the like is used. Of course, this arrangement of the auxiliary elastic body is also applicable to the second to fifth arrangement methods. By arranging the auxiliary elastic body in this way, the holding force of the scale 2 can be reinforced.

In the example shown above, the method of arranging the elastic members 7a and 7d has been described. However, it is needless to say that the elastic members 7b, 7c, 7e and 7f can be similarly arranged. Also, the elastic members 7a 'and 7d' can be arranged at similar positions by providing the depressions 12 or the adhesive 13 shown in FIGS.

In addition, it is also possible to use a cylindrical elastic member 7g as shown in FIG. The elastic member 7g is capable of elastic deformation 71 in the x-axis direction and elastic deformation 72 in the y-axis direction on the xy plane, similarly to the elastic members shown so far, and is deformed in the z-axis direction. The shape is difficult and rigid. The elastic member 7g also has a plurality of projections 75 arranged on the outer periphery of the cylinder in order to increase the frictional force generated on the side surface of the scale 2 and the side surface of the groove 11. In this example, the elastic member 7g has the projection 75 to increase the frictional force. However, for example, a method such as applying a surface treatment so as to increase the friction coefficient without disposing the projection 75 may be used. FIG. 20 shows an example in which the elastic members 7g are arranged according to the first arrangement method. This figure is observed from the direction of A in FIG. As can be seen from the figure, the axis of the elastic member 7g and the side surface of the scale 2 are parallel. In this case, in order to set the elastic member 7g between the scale 2 and the side surface of the groove 11, the elastic member 7g is set while being crushed. Accordingly, the scale 2 can be held by a stronger elastic force, and even when a hysteresis difference is generated between the scale 2 and the groove 11 due to thermal expansion, the elastic member 7g performs elastic deformation and rotational movement, The influence of the thermal expansion displacement can be reduced. Further, since the shape is not easily deformed on the zy plane, it is possible to prevent the scale 2 from being detached from the groove 11. Of course, this elastic member 7g can be applied to the second to sixth arrangement methods described above.

[0032]

As described above, according to the scale holding mechanism according to the present invention, the scale holder of the scale due to external vibration or the like is allowed while allowing the thermal expansion displacement in the measurement axis direction generated between the scale holder and the scale. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a view for explaining a conventional example of a scale holding mechanism in a shield type linear scale.

FIG. 2 is a perspective view for explaining a first arrangement method of an elastic member and a frictional force increasing mechanism of the scale holding mechanism according to the embodiment of the present invention.

FIG. 3 is a perspective view and a plan view showing details of an elastic member in the scale holding mechanism according to the embodiment of the present invention.

FIGS. 4A and 4B are a perspective view and a plan view showing details of a modification of a projection of an elastic member in the scale holding mechanism according to the embodiment of the present invention. FIGS.

FIGS. 5A and 5B are a perspective view and a plan view showing details of a modification of a projection of an elastic member in the scale holding mechanism according to the embodiment of the present invention. FIGS.

FIG. 6 is a perspective view and a plan view showing details of another elastic member in the scale holding mechanism according to the embodiment of the present invention.

FIGS. 7A and 7B are a perspective view and a plan view showing details of a modification of a projection of another elastic member in the scale holding mechanism according to the embodiment of the present invention.

FIGS. 8A and 8B are a perspective view and a plan view showing details of a further modification of a projection of another elastic member in the scale holding mechanism according to the embodiment of the present invention.

FIG. 9 is a perspective view and a plan view showing details of a scale holding mechanism according to an embodiment of the present invention in which a part of a protrusion of an elastic member is removed.

FIGS. 10A and 10B are a perspective view and a plan view showing details of a scale holding mechanism according to an embodiment of the present invention in which a portion of a projection of another elastic member is removed.

FIGS. 11A and 11B are a perspective view and a plan view showing details of a method of arranging an elastic member in the scale holding mechanism according to the present invention in which a part of a projection is removed.

12A and 12B are a perspective view and a plan view showing details of another arrangement method of the elastic member in the scale holding mechanism according to the present invention in which a part of the projection is removed.

FIG. 13 is a view for explaining a first arrangement method of the elastic member and the frictional force increasing mechanism of the scale holding mechanism according to the embodiment of the present invention.

FIG. 14 is a view for explaining a second arrangement method of the elastic member and the frictional force increasing mechanism of the scale holding mechanism according to the embodiment of the present invention.

FIG. 15 is a view for explaining a third arrangement method of the elastic member and the frictional force increasing mechanism of the scale holding mechanism according to the embodiment of the present invention.

FIG. 16 is a view for explaining a fourth arrangement method of the elastic member of the scale holding mechanism and the frictional force increasing mechanism according to the embodiment of the present invention.

FIG. 17 is a view for explaining a fifth arrangement method of disposing an elastic member, a frictional force increasing mechanism, and an adhesive of the scale holding mechanism according to the embodiment of the present invention.

FIG. 18 is a view for explaining a sixth arrangement method of the elastic member, the auxiliary elastic body, and the frictional force increasing mechanism of the scale holding mechanism according to the embodiment of the present invention.

FIG. 19 is a perspective view and a plan view showing details of a cylindrical elastic member of the scale holding mechanism according to the embodiment of the present invention.

FIG. 20 is a diagram showing an example of the arrangement of the cylindrical elastic member of the scale holding mechanism according to the embodiment of the present invention between the scale side surface and the groove side surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scale holder, 2 ... Scale, 3 ... Cylindrical rubber, 4, 5 ... Elastic adhesive, 6 ... Friction force increasing mechanism, 7
a, 7b, 7c, 7d, 7e, 7f, 7g, 7a ', 7
d ': elastic member, 8: frictional force reducing mechanism, 9a, 9b ...
Auxiliary elastic body, 11 groove, 12 recess, 13 adhesive, 14 adhesive layer, 71, 72 elastic deformation, 73, 7
4, 75... Protrusions.

Claims (17)

[Claims] 1. A scale having a measuring axis in a longitudinal direction, a scale holder having a groove for holding the scale at one end, and at least one surface facing a first side surface of the groove of the scale. A frictional force increasing mechanism formed on the scale, the frictional force increasing mechanism of the scale is inserted and arranged in a gap between the frictional force increasing mechanism and the first side surface of the groove, and the measurement axis direction is between the scale and the scale holder. Allow relative displacement,
An elastic member that suppresses relative displacement in a direction orthogonal to the measurement axis within the plane of the scale and generates a force that presses the scale toward the second side surface of the groove. Scale holding mechanism. 2. The scale holding mechanism according to claim 1, wherein the elastic member includes a projection fixed to the frictional force increasing mechanism. 3. The scale holding mechanism according to claim 1, wherein the elastic member is made of a metal spring material. 4. The scale according to claim 1, wherein a plurality of the elastic members are arranged in the longitudinal direction of the scale.
6. The scale holding mechanism according to claim 1. 5. The elastic member according to claim 1, wherein said elastic member is formed by bending a plate-like elastic material into a U-shape.
The scale holding mechanism as described. 6. The scale holding mechanism according to claim 1, wherein said elastic member has a cylindrical shape. 7. The system according to claim 1, wherein the frictional force increasing mechanism is formed continuously in the longitudinal direction of the scale.
7. The scale holding mechanism according to any one of claims 6 to 6. 8. The scale holding mechanism according to claim 1, wherein the frictional force increasing mechanism is divided into a plurality of pieces in the longitudinal direction of the scale corresponding to the elastic member. 9. The scale holding mechanism according to claim 4, wherein a relative displacement of the scale in the measurement axis direction with respect to the groove is restricted at one position in a longitudinal direction. 10. The scale and the groove are adhesively fixed at one location in the longitudinal direction of the scale by an adhesive layer, and at least in the measurement axis direction of the scale and the groove at the part adhesively fixed by the adhesive layer. 10. The scale holding mechanism according to claim 4, wherein relative displacement is regulated. 11. The scale holding mechanism according to claim 1, wherein a frictional force reducing mechanism is formed between the second side surface of the groove and the scale. 12. The scale holding mechanism according to claim 1, wherein the frictional force increasing mechanism is formed by a coating process. 13. The method according to claim 1, wherein the frictional force increasing mechanism is formed by machining.
12. The scale holding mechanism according to any one of 11 above. 14. The scale holding mechanism according to claim 1, wherein the frictional force increasing mechanism is formed by attaching a tape for increasing a frictional force. 15. The scale holding mechanism according to claim 11, wherein the frictional force reducing mechanism is formed by a coating process. 16. The scale holding mechanism according to claim 11, wherein the frictional force reducing mechanism is formed by attaching a tape for reducing a frictional force. 17. The scale holding mechanism according to claim 4, further comprising an auxiliary elastic body that presses the scale toward the second side surface of the groove between adjacent elastic members.