JPS5836725B2 - Optical displacement measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical displacement measuring device that reads and measures relative movement between a main scale and an index scale facing the main scale using a light source and a light receiving element.

Conventional measuring instruments of this type have a main scale made of glass or the like placed along the longitudinal direction in a hollow elongated case formed by cold drawing, and an index scale placed opposite this main scale. The index scale is attached via a slider to the arm of the detection mechanism, which is a moving member inserted through an opening formed along the longitudinal direction of the case, and a light emitting element and a light receiving element are provided on the slider to form the detection mechanism. The relative movement with the case is measured by detecting the light and darkness formed between both scales using a light receiving element.

The slider is movably provided on the arm of the detection mechanism via a linear spring, and is urged to one side by the linear spring, so that the contactor provided on the slider contacts the scale surface of the main scale and the scale. It is designed to come into contact with the side perpendicular to the surface.

As a result, the slider moves while being guided by the scale surface and side surface of the linear scale, so that the slider can move with the scale part of the main scale and the scale part of the index scale facing each other.

However, in such conventional optical displacement measurement devices, the contact force between the slider having the main scale and the index scale is maintained only by one linear spring, so when the slider moves, the linear The spring may deform and the pressure force may change, causing the slider to float on one side relative to the main scale.

In this way, if the contact between the linear scale and the slider becomes uncertain, the hard striped graduations of the linear scale and the hard striped graduations of the index scale attached to the slider will no longer be parallel, resulting in miscounts. It is the cause of

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical displacement measuring device that can perform stable movement with a uniform pressing force even when a main scale and an index scale move relative to each other.

The present invention connects an index scale to a movable member so as to be able to move toward and away from the moving member and swing the same, and a magnetic member is provided on the main scale, and a magnet is provided on the index scale at positions shifted in the width direction of the main scale. In this way, the above object is achieved by configuring the structure so that the adhesion force acts in both the width direction of the main scale and the direction perpendicular to the surface of the main scale.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

A case 1 formed by cold drawing force Roe has a substantially rectangular hollow cross section and is elongated in the direction perpendicular to the plane of the paper in FIG. have.

A detection mechanism 3 as a moving member is brought into contact with the opening side end surface of the case 1 via a pair of sliding members 4.
It is said that it is movable along the longitudinal force direction.

The arm portion 5 formed on the lower surface of this detection mechanism 3 is connected to the opening 2.
It is extended into case 1.

Further, a pair of magnets 6 are provided on the outer surface of the case 1 near the opening 2 along the longitudinal force direction of the case 1,
A closing member 7 made of a thin iron plate is attracted to the magnet 6 so as to cover the opening 2, thereby preventing dust and the like from entering the case 1 from the opening 2.

At this time, the detection mechanism 30) is inserted into a side chevron-shaped groove 8 provided in the detection mechanism 3 and having both ends opened on the lower surface of the detection mechanism 3, in which the closing member 7 and the arm 5 are inserted. The arm portion 5 that is straddled by this groove 8 is the case 1
It is possible to insert it inside.

Into the groove 9 provided in the longitudinal direction of the case 1 is inserted the lower end of a main scale 10 made of glass or the like and having vertical striped graduations 10A (see FIG. 2) formed on one side. , and are fixed with adhesive 11 or the like.

The arm portion 5 of the detection mechanism 3 is extended into the case 1, and a recess 5A cut out from one side and a lower surface is formed in this extension, and the portion of FIG. Elongated holes 5B are formed in the front and rear walls perpendicular to the inner paper surface, respectively.

A slider 1 is inserted into this elongated hole 5B via a bearing 12.
The upper end of 3 is supported so as to be swingable and vertically movable.

The slider 13 is a connecting member 1 formed from a plate material.
3A, and a thick light emitting element mounting member 13B that is screwed to one bent short side of the connecting member 13A and is opposed to the surface of the main scale 10 that does not have the scale 10A.
The connection member 13A is configured with a thick light receiving element mounting member 13C whose upper end is screwed in the middle and is opposed to the surface on which the scale 10A of the main scale 10 is formed. This is done via a pin 13D provided at the upper end of the connecting member 13A.

At this time, the inner end surface of the inner ring of each bearing 12 and the connecting member 1
Disc springs 13B are interposed between the side surfaces of the arm portions 5 and 3A, respectively, to prevent a gap from being formed between the connecting member 13A and the end surface of the bearing 12, and to prevent the formation of a gap between the connecting member 13A and the end surface of the bearing 12. movements are transmitted immediately.

An index scale 14 having vertical striped graduations 14A similar to the main scale 10 is provided on the surface of the connecting member 13A of the slider 13 facing the main scale 10.
is fixed.

A light emitting element 15 as a light source and a light receiving element 16 such as a phototransistor are arranged with the index scale 14 and main scale 10 sandwiched therebetween.

At this time, the light emitting element 15 is attached to the light emitting element mounting member 13B fixed to the short side of the connecting member 13A, and the light receiving element 1
6 are fixed to two light receiving element mounting members 13C fixed in the middle of the connecting member 13A.

Index scale 1 of the light receiving element mounting member 13C
4 is attached, two magnets 17 are embedded with the index scale 14 in between, and pins 18 are provided on the sides of these magnets 17 at positions slightly below the center of the magnets 17. It is planted.

This pin 18 is made of hardened steel or the like, and its tip protrudes from the surface of the light-receiving element mounting member 13C.

Further, a stepped portion 13F is formed approximately in the lower half of the surface of the light receiving element mounting member 13C on which the index scale 14 is attached, and approximately the lower half of the magnet 17 is also formed into a stepped portion 17A in accordance with this stepped portion 13F. is formed.

By providing this stepped portion 13F, a portion of the lower surface of the pin 18 is exposed downward from the stepped portion 13F.

The guide bar 1 is placed opposite the exposed lower surface of the pin 13.
9 is placed.

The guide bar 19 is made of a magnetic member such as a steel strip, is attached parallel to the scale 10A along the longitudinal direction of the main scale 10, and is positioned within the stepped portion 13F of the light-receiving element mounting member 13C. It is designed to fit in with a gap.

Further, the narrow upper surface of the guide bar 13 is precision-machined to have sufficient straightness, and the pin 1B is abutted on this upper surface.

That is, the guide bar 19 and the magnet 17, which are made of a magnetic member, are arranged at positions shifted from each other in the width direction of the main scale.

Index scale 1 of the light receiving element mounting member 13C
A yoke 20 for closing the magnetic path of the two magnets 17 is attached to the surface opposite to the surface on which 4 is attached, and a portion of this yoke 20 is embedded in the light receiving element mounting member 13C. are in contact with the back surfaces of both magnets 17.

In addition, rollers 21 are provided at three locations on the cut arrow portions provided at both ends of the upper surface of the light-receiving element mounting member 13C and at the center of the lower surface.
are rotatably provided, and these rollers 21 are allowed to come into contact with the surface of the main scale 10 on which the scale 10A is formed.

As a result, when the light-receiving element mounting member 13C is attracted in the width direction of the main scale 10 by the main scale width direction component of the magnetic force acting between the magnet 17 and the guide bar 19, the bottle 18 is placed on the upper surface of the guide bar 19. On the other hand, when the light-receiving element mounting member 13C is attracted in the direction perpendicular to the main scale surface by the component of the magnetic force acting between the magnet 17 and the guide bar 19 in the direction perpendicular to the main scale surface, each roller 21 scale 1
It is designed to abut and support the 0 scale surface.

That is, the relative positions of the main scale 10 and the index scale 14 in the main scale width direction are maintained constant by the main scale width direction component of the magnetic force acting between the magnet 17 and the guide bar 19 and the pin 18. The distance between the main scale 10 and the index scale 14 in the direction perpendicular to the main scale surface is maintained constant by the component of the magnetic force acting between the index scale 10 and the index scale 19 in the direction perpendicular to the main scale surface and the roll 21.

In such a configuration, when either the case 1 or the detection mechanism 3 as a moving member is attached to the object to be measured and the other is fixed and the object to be measured is moved, the scale 10A of the main scale 10 and the index A bright and dark striped pattern is generated between the graduations of the scale 14, and this striped pattern is transferred to the light emitting element 1.
5 and the light receiving element 16 to read the amount of movement of the object to be measured and perform measurement.

At this time, the slider 13 is provided to be swingable by the bearing 12 and the elongated hole 5B, and to be movable in the vertical direction in the figure. is located and a magnetic force in the direction of close contact is working between them, so the pin 18 is attached to the guide bar 1.
9 and each roller 21 is in close contact with the upper surface of the main scale 1.
The light-receiving element mounting member 13C is urged to come into close contact with the 0 scale surface, so that the light-receiving element mounting member 13C can stably move along the main scale 10.

Therefore, the scale 10A of the main scale 10 and the scale 14A of the index scale 14 are also accurately moved in parallel, and no counting errors by the light receiving element 16 occur.

As described above, according to this embodiment, the adhesion force of the index scale 14 to the main scale 10 side is determined by the magnet 17 provided on the index scale 14 and the main scale width provided on the main scale 10 and with respect to the magnet 17. Guide bar installed at a position shifted in the direction
19, it is possible to slide the bearing 21 of the slider 13 and the main scale 10, and the pin 18 and the guide bar 19 in a stable and close state without floating or the like. Completed, main scale 10 scale 10A and index scale 1
Counting errors due to the inclination with the 4th scale can be prevented.

Furthermore, index scale 14 and main scale 1
Since the relative position with respect to 0 in the width direction of the main scale is always constant, the signal level never decreases.

Furthermore, since the slider 13 is guided during movement by the pin 18 and the upper surface of the guide bar 19, it can be guided at low cost and with high precision, unlike the conventional method of guiding the upper end surface of the main scale 10.

Furthermore, since the slider 13 is not attached to the arm portion 5 via an unstable member such as a spring, variations in accuracy can be reduced, and the main scale
Since the slider 13 moves only following the scale surface of 0, it can faithfully follow the distortion of the main scale 10 and maintain high accuracy.

The magnet 17 has a stepped portion 17A at about half the position.
A guide bar 1 made of a magnetic material is provided inside this stepped portion 17A.
Since the pin 9 is inserted into the pin 18, the pin 18 is biased by the biased magnetic force so that it always comes into contact with the upper surface of the guide bar 19, and this also increases the stability during movement.

In addition, in implementation, the guide bar 19 side may be made of a magnet, and the magnet 17 side may be made of a simple iron material, etc.
The above embodiment has the effect of being inexpensive.

Furthermore, the shapes of the magnet 17 and the guide bar 19 are not limited to the shapes of the embodiments described above, and may be of any shape, such as a round bar for the guide bar 19.

In short, the magnet 17 and the guide bar 19 are provided at positions shifted in the width direction of the main scale, and the index scale 14 attached to the slider 13 is attached to the magnet 1.
The main scale 10 may be biased in the width direction of the main scale 10 and in a direction perpendicular thereto by the magnetic force generated between the main scale 7 and the guide bar 19 .

Furthermore, the bearing 12 that supports the upper end of the slider 13 is not necessarily provided, but if it is provided, there is an advantage that the operation becomes smoother.

Also, a bearing 21 that comes into contact with the main scale 10
Alternatively, a small piece made of a resin having a low coefficient of friction may be brought into contact with the surface.

As described above, according to the present invention, it is possible to provide an optical displacement measuring device in which the pressing force of the index scale to the main scale is stable and there are fewer measurement errors due to miscounts.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the optical displacement measuring device according to the present invention, FIG. 2 is a perspective view of the main scale and slider shown in FIG. 1, and FIG. 3 is an exploded perspective view of the slider. FIG. 4 is a front view with a part of the main part cut away, showing how the slider and the arm are attached. 1...Case, 2...Opening, 3...
...Detection mechanism, 5...Arm part, 10...
・Main scale, 10A...Scale, 13...
...Slider, 14.Track/index scale, 14A...Scale, 15...Light emitting element, 16...Light receiving element, 17...Magnet , 18... Pin, 19... Guide bar made of a magnetic member.

Claims (1)

[Claims] 1. A main scale disposed along the longitudinal force direction in a hollow elongated case and formed with scales at predetermined intervals, a movable member assembled to the hollow elongated case and capable of sliding in the longitudinal direction of the hollow elongated case, and An index scale that is connected to a member and is placed opposite the main scale and has graduations at predetermined intervals, and a light source and light receiver that read the relative movement between the main scale and the index scale based on the degree of overlapping of the graduations of both scales. In the optical displacement measuring device, the index scale is supported by a movable member so as to be able to move toward and away from it and swing, and a magnetic member is attached to the main scale, and a magnet is attached to the index scale, which are displaceable in the width direction of the main scale. The distance between the index scale and the main scale is kept constant by the vertical component of the magnetic force acting between the magnet and the magnetic member, and by the rollers installed on the index scale that move over the main scale surface. At the same time, the index scale and main scale are held in the width direction by the component of the magnetic force acting between the magnet and the magnetic member in the width direction of the main scale and the projections that protrude from the index scale and come into contact with the side edges of the magnetic member. An optical displacement measuring device characterized in that the relative position is maintained constant.