JPH10239003A - Displacement sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact, practical, high-accuracy displacement sensor easily allowing stable winding work. SOLUTION: This displacement sensor 1 is provided with a scale coil 5 fixedly arranged on a case body 3 and a slider coil 7 slidably arranged in the scale coil 5. The scale coil 5 is provided with two coil sets 9, 9 across a spacer 11. Multiple base rings 13, coils 15 wound on the outer peripheries of the large- diameter sections of the base rings 13, and yokes 17 coupled to be suspended on the outer peripheries of the small-diameter sections of the adjacent base rings 13 are arranged on one coil set 9. The width of the spacer 11 is formed so that the pitch of the coils 15 of one coil set 9 is matched with the pitch of the coil 8 of the slider coil 7 and the pitch of the coils 15 of the other coil set 9 is drifted by the 1/4 pitch against the pitch of the coil 8 of the slider coil 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction type displacement sensor such as an electric micrometer, and further includes a scale coil fixed to a case body, a slider coil sliding in the scale coil, and And a displacement sensor that electrically converts a position displacement caused by sliding of the slider coil.

[0002]

2. Description of the Related Art Conventionally, a flat type inductosin used for a machine tool or the like is often used for an electromagnetic induction type displacement sensor. As shown in FIG. 11, the induct thin 70 is configured so that a slider coil 71 having a pattern formed on a flat plate and a scale coil 72 face each other. When an AC voltage is applied to the scale coil 72 to excite it, an AC voltage is induced on the slider coil 71 side, and the magnitude and direction of the voltage changes depending on the positional relationship of the pattern pitch. The displacement between the position of the scale coil 71 and the scale coil 72 is detected. Especially the slider coil 7
The detection pattern formed in 1 is shifted by 1/4 pitch, and by comparing the signal with the signal shifted by 90 °, highly accurate detection is possible.

However, when used in a small measuring instrument such as an electric micrometer, the size is large and the dimensional accuracy is high when forming a pattern. . Therefore, a cylindrical displacement sensor that is compact and can be easily manufactured has been proposed.

[0004] For example, an electric micrometer 80 shown in FIG. 12 is a movable iron core type differential transformer, which is wound around an insulated bobbin 81, and has one primary coil 82 disposed at a center position of the bobbin 81. , Two secondary coils 83 wound on both sides of the primary coil 82, and a movable core 84 located at the center of the primary coil 82 and the secondary coil 83.

[0005] Each voltage in the secondary coil 83 is excited by the addition of a constant AC voltage to the primary coil 82 v _a, v _b is generated. When the movable core 84 is located at the center of the two secondary coils 83, v _a = v _b , and the movable core 84
Moving to the right outputs a positive voltage, and moving to the left outputs a negative voltage. Then, when the two secondary coil voltages are rectified and smoothed by diodes and added and combined, an output voltage v is obtained in proportion to the displacement. However, the conventional differential transformer type electric micrometer is output in analog form, which causes unstable linearity due to fluctuations in the output voltage, and machine differences due to the number of coil turns and the length of the movable core. , You have to calibrate it. In order to solve this, a digital electric micrometer with high accuracy has been proposed as shown in FIG.

The electric micrometer 90 includes a displacement sensor 94 having two scale coils 92 fixed to a main body case 91 and a slider coil 93 slidably disposed inside the scale coil 92. Have been. A coil groove 95 is formed from the inner peripheral surface to the back so that two coils are wound around the scale coil 92, and a coil groove is formed from the inside of the scale coil 92 toward the bottom of the coil groove 95. Is to be wound. The two scale coils 92 are provided at the center with a spacer 96.
Accordingly, one scale coil 92 is arranged so as to be shifted by a quarter pitch from the other scale coil 92 with respect to the pitch of the coil of the slider coil 93. Therefore, compact and accurate measurement is possible.

[0007]

However, in the displacement sensor 94 of the electric micrometer 90 described above, it is difficult to process the coil groove 95 formed in the scale coil 92, and the operation of winding the coil requires the coil. This is very difficult because the coil must be wound with reference to the bottom of the groove 95, or the wound coil must be inserted into the coil groove 95.

An object of the present invention is to solve the above-mentioned problems and to provide a compact and accurate displacement sensor and a practical displacement sensor capable of easily performing a stable winding operation. And

[0009]

The displacement sensor according to the present invention has the following configuration to solve the above-mentioned problems. That is, the scale coil includes a scale coil fixed to a case body formed of a magnetic material and formed in a hollow shape, and a slider coil slidably disposed in a hollow portion of the scale coil. A displacement sensor for electrically converting displacement due to sliding, wherein the scale coil has a space member provided between two coil sets and the coil set and formed of a nonmagnetic material. So that the coil set is sandwiched between the plurality of base rings formed of a non-magnetic material, the coils wound around the outer peripheral surface of each base ring, and the coils. And a ring-shaped yoke formed of a magnetic material.

Preferably, an outer peripheral surface of the base ring has a large diameter portion and a small diameter portion, and the coil is wound around an outer peripheral surface of the large diameter portion, and the yoke is formed on an outer peripheral surface of the small diameter portion. May be fitted as long as they are fitted.

Further, the pitch between the coils formed on one of the coil sets matches the pitch between the coils formed on the slider coil, and the pitch between the coils formed on the other coil set is the same as the pitch between the coils formed on the other coil set. It is more preferable that the spacer has a width so as to cause a pitch shift between the coils formed in the slider coil.

The displacement sensor includes a scale coil fixed to a case body made of a magnetic material and formed in a hollow shape, a slider coil slidably disposed in a hollow portion of the scale coil, and Wherein the scale coil has one split portion parallel to the axial direction and is formed of a non-magnetic material. A plurality of base rings, and an outer peripheral surface of the base ring includes a protrusion projecting so as to be bent from the inside to the outside, and the protrusions are arranged so as to be positioned at predetermined intervals. A plurality of coils are wound around an outer peripheral surface of the protrusion, and a magnetic material is formed on an outer peripheral surface of the base ring where the protrusion is not formed. Is Is characterized in that the spacer is formed by the yoke or non-magnetic material is disposed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a displacement sensor 1 of the present embodiment has a scale coil 5 fixed to a case body 3 made of a magnetic material and formed in a hollow shape, and a hollow portion of the scale coil 5. Slider coil 7 slidably disposed
, And is configured. As shown in FIG. 2, the scale coil 5 includes two coil sets 9.9 and a spacer 11 formed between the coil sets 9.9 and formed of a non-magnetic material. The coil set 9 is polymerized in the direction by an adhesive or the like, and the coil set 9 includes a plurality of (two in this embodiment) base rings 13 formed of a non-magnetic material and
3 and a ring-shaped yoke 17 formed of a magnetic material and arranged to sandwich the coil.

The base ring 13 is formed in a ring shape, and the outer peripheral surface of the base ring 13 has a large-diameter portion 14 disposed substantially at the center.
Are formed in two stages: a large-diameter portion outer peripheral surface 14a and small-diameter portion outer peripheral surfaces 13a and 13b disposed on both sides of the large-diameter portion 14. In addition, the small diameter portion outer peripheral surfaces 13a and 13b of the base ring 13 have different widths, and one of the small diameter portion outer peripheral surfaces 13a and 13b.
Is formed to be approximately twice as large as the other small-diameter portion outer peripheral surface 13 b, and the width of the small-diameter portion outer peripheral surface 13 a is formed to be substantially the same as the width of the yoke 17. And each coil body 9
The base ring 13 is arranged such that one small-diameter portion outer peripheral surface 13a is on both outer sides of the base ring 13, and the other small-diameter portion outer peripheral surface 13b is arranged on the inner side. Therefore,
The yokes 17 are fitted one by one on the small-diameter portion outer peripheral surface 13a, and one yoke 17 is fitted so as to be suspended on two opposing small-diameter portion outer peripheral surfaces 13b. The coil 15 is wound and arranged on the large-diameter portion outer peripheral surface 14 a between the yokes 17. The adjacent coils 15 are wound and arranged so that the winding directions are opposite. Further, both end faces of the scale coil 5 are substantially flush with the end face of the base ring 13 and the end face of the yoke 17. Further, as shown in FIG.
One notch 17a is formed in a part of the outer end, and the notches 17a of the respective yokes 17 are arranged so as to be in the same direction. One end of each coil 15 is connected to the yoke 1 so that each coil 15 can conduct.
7, are bundled together at both ends of the coil body 9 and wired outside (see FIG. 4). in this case,
A cutout may be formed in the spacer 11 and wired together on one side.

The slider coil 7 has an outer peripheral surface formed in a round shape so as to be slidably disposed in the hollow portion of the scale coil 5, and has a through hole 7a formed therein in the axial direction. A plurality of coil grooves 7b are formed at equal pitch intervals on the outer peripheral surface, and a coil 8 is wound around each coil groove 7b. The pitch of the coil groove 7b is formed to be the same as the pitch of the coil 15 wound around the coil set 9. In addition, the winding direction of the coil 8 wound around the coil groove 7b is opposite to the winding direction of the adjacent coil 8, similarly to the coil 15 wound around the scale coil 5. Also,
One notch 7c is formed at a part of the outer end of the slider coil 7, and one end of each coil 8 passes through the notch 7c so that one coil 8 can conduct. And are wired outside (see FIG. 5).

The spacer 11 is formed in a cylindrical shape such that the outer peripheral surface coincides with the outer peripheral surface of the yoke 17 and the inner peripheral surface coincides with the inner peripheral surface of the base ring 13. The coils 15 of the set 9 are formed so that the pitch of the coils 15 is shifted from the pitch of the coil 8 of the slider coil 7 by 1/4 pitch. As described above, a cutout may be formed at one portion of the outer end of the spacer 11.

The base ring 13 or the spacer 11 constituting the above-described scale coil 5 is not limited to the above, and various modifications are conceivable as shown in FIGS.

FIG. 6 shows one coil set 2
In this case, four base rings are disposed with respect to the base member 0, one base ring 21 disposed on the outer end side of the coil set 20 in the case body 3, and one base ring disposed on the inner spacer side. And three base rings 23 to be formed. The base ring 21 has an outer peripheral surface 22a of a large-diameter portion 22 in which the outer peripheral surface is disposed substantially at the center.
And a small-diameter portion outer peripheral surface 21a disposed on both sides of the large-diameter portion 22
21b, and one outer peripheral surface 21a of the small diameter portion is formed to have the same width as the yoke 17 and is disposed outside. The other small-diameter portion outer peripheral surface 21b is formed to have a width larger than the yoke 17 and is arranged on the base ring 23 side. On the outer peripheral surface of the base ring 23, an outer peripheral surface 24 a of the large diameter portion 24 and a small diameter outer peripheral surface 23 a disposed on the other end side are formed on one end side.
Is formed with a concave portion 24b. The coil 15 is wound around the large-diameter portion outer peripheral surface 22a of the base ring 21 and the large-diameter portion outer peripheral surface 24a of the base ring 23, and the concave portion 24b of the large-diameter portion 24 of the base ring 23 adjacent to the base ring 21. Is fitted to the outer peripheral surface 21b of the small diameter portion of the base ring 21 so as to sandwich the yoke 17, and the concave portion 24a of the large diameter portion 24 of the other base ring 23 has the small diameter of the base ring 23 adjacent to the base ring 21 side. The yoke 17 is fitted to the outer peripheral surface 23a so as to sandwich it. The coil set 20 of this embodiment has three base rings 23.
Are formed in the same shape.

In FIG. 7 as well, four base rings are arranged for one coil set 30 arranged in the case body 3, and the spacer shape is further modified. The outer peripheral surface of the spacer 31 has an outer peripheral surface 3 of the large diameter portion 32 at the center.
2a and a small diameter outer peripheral surface 31a at both ends. Three base rings 3 arranged on the spacer 31 side
The outer peripheral surface of the small-diameter portion 3 has an outer peripheral surface 35a of the large-diameter portion 35 at the center portion and a small-diameter outer peripheral surface 34a at both ends.
4a is the outer diameter of the small diameter portion 31a of the spacer 31.
It is formed in the same size as. Small diameter portion outer peripheral surface 3 of base ring 34 adjacent to small diameter portion outer peripheral surface 31a of spacer 31
The yokes 17 are respectively arranged so as to suspend between the outer peripheral surfaces 34a of the small diameter portion 4a or the adjacent base ring 34. The outer peripheral surface of one base ring 37 disposed outside the coil set 30 has a large diameter portion 38 disposed substantially at the center.
And the outer peripheral surface 38a of the base ring 3 and the outer peripheral surfaces 37a and 37b of the small diameter portions disposed on both sides of the large diameter portion 38.
The small-diameter portion outer peripheral surface 37a adjacent to the fourth side is formed to have the same width as the small-diameter outer peripheral surface 34a of the base ring 34, and the yoke 17 is fitted so as to suspend between the small-diameter portion outer peripheral surface 34a of the base ring 34. The small-diameter portion outer peripheral surface 37b arranged outside the base ring 37 is formed to have the same size as the width of the yoke 17, and the yoke 17 is fitted. The coil 15 is wound around the large-diameter portion outer peripheral surface 35a of the base ring 34 and the large-diameter portion outer peripheral surface 38a of the base ring 37, respectively.

The scale coil 40 shown in FIG. 8 is the same as the base ring 1 of the coil set 9 of the scale coil 2 shown in FIG.
Between the base ring 3 and the base ring 3 of the coil set 30 in FIG.
4 and the coil 15 and the yoke in FIG.
Are arranged as shown in FIG.

The displacement sensor 1 configured as described above
For example, an electric micrometer 50 as shown in FIG.
Can be used for The coil set of the displacement sensor shown in FIG. 9 will be described with reference to FIG.

A scale coil 5 and a slider coil 7 are housed inside a case body 51 which is formed in a cylindrical shape and made of a magnetic material.
Is provided. In the case of this embodiment, the case body 3 included in the displacement sensor 1 is replaced with the case body 51 of the electric micrometer 50. In addition,
Another case body 3 may be provided on the inner peripheral surface of the case body 51.

The scale coil 5 is fixed in a case body 51, and a slider coil 7 is slidably disposed in the scale coil 5. On one side of the through hole 7a formed in the slider coil 7, a female screw 52 is formed.
A tracing stylus 53 is screwed to the case 2 while being supported by the case body 51. A guide shaft 54 fixed to an end of the case body 51 is attached to the other side of the through hole 7a of the slider coil 7, and the slider coil 7 slides while being guided by the guide shaft 54. A coil spring 55 is arranged around the guide shaft 54 so as to bias the slider coil 7 toward the tracing stylus 53.

A lead wire 15 bundled at one end of the coil 15 of the scale coil 5 and one end of the coil 8 of the slider coil 7
a.8a is wired outside through a cable 56 fixed to the case body 51.

The operation of the electric micrometer 50 having the above configuration will be described below. First, when the tracing stylus 53 is applied to the object to be measured, the slider coil 7 and the scale coil 5
9 slides rightward in FIG. 9 against the urging force of the coil spring 55. An AC voltage is applied to the coil 8 of the slider coil 7 in advance, and an AC voltage is induced in the coil 15 of the scale coil 5 by electromagnetic induction. When the slider coil 7 slides, the positional relationship between the coil 8 of the slider coil 7 and the coil 15 of the scale coil 5 changes, so that the degree of electromagnetic induction between the coil 8 and the coil 15 changes. That is, the magnitude of the AC voltage induced in the coil 15 changes according to the magnitude of the sliding amount of the slider coil 7. This voltage signal is processed to electrically convert the displacement amount.

For example, let X be the displacement amount. At this time, the respective coil sets 9A and 9B of the scale coil 5
Let Va and Vb denote the voltages output from, respectively, Va = KI sin (2πX / P) sinωt Vb = KIcos (2πX / P) sinωt

K: Induction coefficient of the scale coil 5 in the coil set 9 P: Coil winding pitch I: Amplitude of current of the slider coil 7 ω: Angular frequency of the slider coil 7 t: Time X: Displacement movement amount

When Va and Vb are measured and the output voltages of Va and Vb are combined (V), V = KIsin (ωt + 2πX / P).

Here, the displacement X is a phase change of 2πX.
/ P.

For example, P = 2 mm, and electrically 2000
Divide equally and measure in 1 μm units. If the difference between the output voltage (Vc) of the slider coil 7 and the combined output voltage (V) of the scale coil 5 is N = 780 counts, 780 /
2000 = 2π (X / P) / 2π, X = 780 × 2/2000 = 0.78 mm, and the displacement / movement amount X can be obtained, and the object to be measured can be measured.

When the displacement sensor 1 is used for the electric micrometer 50 as described above, the displacement sensor 1 can be electrically converted to measure the amount of displacement.

It should be noted that the shape of the scale coil 5 of the displacement sensor 1 of the present invention is not limited to the above, but may be other forms.

FIGS. 10A and 10B show a base ring 61 formed in a coil set 60 of a scale coil. The base ring 61 is formed by forming one of the above-described plurality of base rings into one. A part of the base ring 61 formed of a non-magnetic material such as stainless steel in a cylindrical shape is provided with a split portion 62 along the axial direction. Is provided. When the yoke 17 shown in FIG. 2 is mounted, the split portion 62 allows the entire base ring 61 to be bent in the circumferential direction. A plurality of projections 63 for winding the coil 15 shown in FIG. 2 are formed in the circumferential direction of the base ring 61. This projection 63
In FIG. 2, three or four pieces are equally arranged in the circumferential direction at positions where the pitch is the same as the pitch at which the base rings 13 are arranged, and are notched in the circumferential direction except one end from the base ring 61. And is formed so as to protrude upward. FIG. 10 shows that protrusions 63 are formed at substantially equal intervals on both the left and right sides, leaving a width corresponding to the arrangement of the spacer 11 and the two yokes 17 in FIG. ing. A spacer 11 and two yokes 17 are fitted into the center of the base ring 61 so as to sandwich the spacer 11, and a projection 63 and a projection 63 are provided.
The yokes 17 are fitted between the yokes 17 and the both ends to form a coil bobbin.
The scale coil is formed by winding the coil 15 between the coils 7 and providing the case body 3 around the coil 15. Needless to say, the right and left coil sets of the scale coil with the spacer 11 interposed therebetween are shifted by 1/4 pitch from the pitch of the coil 8 of the slider coil 7.

The present invention is not limited to the above, and the base body 61 can be formed in a size for each coil set.

[0036]

According to the displacement sensor of the present invention, the displacement sensor includes a scale coil fixedly disposed on the case body and a slider coil slidably disposed in the scale coil. I have. The scale coil has two coil sets and a spacer, and the coil set is provided on a plurality of non-magnetic base rings superposed in the axial direction and on an outer peripheral surface of the base ring. And a yoke. Therefore, when the coil is wound around the base ring, the coil can be wound along the outer peripheral surface of the base ring. Therefore, the coil is wound around the bottom of the coil groove in the coil groove formed in the conventional scale coil. As compared with the case of winding, the winding can be performed very stably and the operation can be performed very easily.

The outer peripheral surface of the base ring has a large diameter portion and a small diameter portion, the coil is wound on the outer peripheral surface of the large diameter portion, and the yoke is fitted on the outer peripheral surface of the small diameter portion. Therefore, the winding operation of the coil wound around one base ring is easy and stable, and the yoke can be easily inserted.

Further, the pitch between the coils formed on one of the coil sets matches the pitch between the coils formed on the slider coil, and the pitch between the coils formed on the other coil set is the same as the pitch between the coils formed on the other coil set. Since the spacer width is formed so as to cause a pitch shift between the coils formed in the slider coil, accurate measurement can be performed.

Further, at least one base ring is formed for the scale coil, and a plurality of coil winding protrusions are formed on the base ring so as to be bent from the inside to the outside. By doing so, it is possible to reduce the number of parts.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a displacement sensor according to one embodiment of the present invention.

FIG. 2 is a sectional view showing details of a scale coil in FIG. 1;

FIG. 3 is a perspective view of a yoke in FIG. 1;

FIG. 4 is a perspective view of a scale coil in FIG. 1;

FIG. 5 is a perspective view of a slider coil shown in FIG. 1;

FIG. 6 is a sectional view showing another form of the base ring.

FIG. 7 is a sectional view showing another form of the base ring and the spacer.

FIG. 8 is a sectional view showing another embodiment of the scale coil.

9 is a sectional view showing a state in which the displacement sensor of FIG. 1 is used for an electric micrometer.

FIG. 10 is a perspective view and a sectional view showing still another form of the base ring.

FIG. 11 is a diagram showing a conventional flat-type inductosin;

FIG. 12 is a cross-sectional view showing an electric micrometer using a conventional displacement sensor.

FIG. 13 is a sectional view showing a conventional electric micrometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Displacement sensor 3 ... Case 5 ... Scale coil 7 ... Slider coil 8, 15 ... Coil 9 ... Coil set 11 ... Spacer 13 ... Base ring 13a ... Small diameter part outer peripheral surface 14 ... Large diameter part 14a ... Large diameter part Outer peripheral surface 17 ... Yoke

Claims (4)

[Claims] A scale coil fixed to a case body formed of a magnetic material and formed in a hollow shape; and a slider coil slidably disposed in a hollow portion of the scale coil. A displacement sensor for electrically converting displacement caused by sliding of a slider coil, wherein the scale coil is provided between two coil sets and the coil set, and is formed of a non-magnetic material. Wherein the coil set includes a plurality of base rings formed of a non-magnetic material, coils wound around the outer peripheral surface of each of the base rings, and sandwiches the coils. And a ring-shaped yoke made of a magnetic material. 2. An outer peripheral surface of the base ring has a large diameter portion and a small diameter portion, the coil is wound on the outer peripheral surface of the large diameter portion, and the yoke is fitted on the outer peripheral surface of the small diameter portion. The displacement sensor according to claim 1, wherein the displacement sensor is combined. 3. The pitch between the coils formed on one of the coil sets is matched with the pitch between the coils formed on the slider coil, and the pitch between the coils formed on the other coil set is the same as the pitch between the coils formed on the other coil set. 3. The displacement sensor according to claim 1, wherein a width of the spacer is formed so as to cause a pitch shift between coils formed in the slider coil. 4. A scale coil fixed to a case body made of a magnetic material and formed in a hollow shape, and a slider coil slidably disposed in a hollow portion of the scale coil, What is claimed is: 1. A displacement sensor for electrically converting displacement caused by sliding of a slider coil, wherein said scale coil has one split portion parallel to an axial direction and at least one base formed of a nonmagnetic material. The base ring has an outer peripheral surface, and includes a protrusion projecting so as to be bent from the inside to the outside. The protrusions are arranged so as to be positioned at a predetermined interval, and A yoke formed of a magnetic material on an outer peripheral surface of the base ring on which a coil is wound around an outer peripheral surface of the protrusion and on which the protrusion is not formed; There A displacement sensor comprising a spacer formed of a non-magnetic material.