JP2008298675A - Linear sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form first and second channel sensors by winding a winding around each projection magnetic pole formed on both sides of the first core body, and by making a plurality of projection magnetic poles of the second core body correspond to both sides of the first core body. <P>SOLUTION: This linear sensor includes the first core body 1 having a plurality of first and second projected magnetic poles 2, 2A projecting to both sides; the second core body 6 disposed corresponding to the first core body 1; and a plurality of third and fourth projected magnetic poles 15, 15A formed on each inner wall 6a, 6b of the second core body 6, in correspondence with the first and second projection magnetic poles 2, 2A. The linear sensor has a constitution wherein the first channel sensor 20 is formed on the side of the first and second projected magnetic poles 2, 15, and the second channel sensor 30 is formed on the side of the second and fourth projected magnetic poles 2A, 15A. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear sensor, and in particular, a pair of channel sensors is formed by arranging projecting magnetic poles of a second core body on both sides of a first core body having projecting magnetic poles and windings on both sides, and each channel sensor. The present invention relates to a novel improvement for detecting a linear position with high accuracy by reducing the influence of mounting errors such as axial deviation and inclination of each core body by using the sum of the output signals.

  Conventionally, as this type of linear sensor that has been used in the past, a conductor portion is generally provided at a predetermined interval on the outer periphery of a round rod-like rod as in the linear position detection device disclosed in Patent Document 1. A configuration has been proposed in which the rod is inserted into a cylindrical coil case and the linear position of the rod is detected from the coil in the coil case.

The configuration shown in FIGS. 3 and 4 shows a linear sensor manufactured in-house by the applicant, and the inner wall 1a of the first core body 1 having a longitudinal shape is arranged at predetermined intervals along the longitudinal direction. A plurality of projecting magnetic poles 2 are arranged via slots 3.
Each protruding magnetic pole 2 is provided with a winding 4 comprising a known excitation winding and a detection winding, and each winding 4 is connected in series or in parallel and led out to the outside by a lead wire 5. .
The first core body 1 is provided with a second core body 6 in a state in which it is not in contact with the protruding magnetic poles 2 through the gap D.

The second core body 6 is formed in a longitudinal shape similarly to the first core body 1, and the inner wall 6a is provided with a concavo-convex portion 7 formed in a waveform along the longitudinal direction. The core body 1 is configured as a fixed side, and the second core body 6 is configured as a movable side.
Therefore, when the exciting windings (not shown) of the windings 4 are excited and the second core body 6 is linearly moved while being connected to the member to be detected (not shown), the concavo-convex portion 7 and the protruding magnetic pole 2 are obtained. Is detected by a detection winding (not shown) of the winding 4, and the linear position of the second core body 6, that is, the linear position of the member to be detected is detected. The winding 4 is constituted by a known excitation winding and detection winding.

Japanese Patent Publication No. 5-80603

Since the conventional linear sensor is configured as described above, the following problems exist.
That is, in the case of the configuration of the above-mentioned Patent Document 1, a plurality of electrode patterns must be formed on the movable body and a plurality of windings must be formed on the fixed body, which makes the structure complicated and unsuitable for mass production. there were.
Further, in the case of the conventional configuration shown in FIGS. 3 and 4, since only the 1-channel sensor is formed by the first and second core bodies, for example, when the second core body is attached to the member to be detected, If a shaft misalignment or inclination due to a slight misalignment or the like occurs in the mounting state, an accuracy error in linear position detection occurs, and there is a limit to highly accurate position detection.

  A linear sensor according to the present invention has a first core body having a plurality of first and second projecting magnetic poles that are formed in a longitudinal flat plate shape and project on both sides, and a first channel for a first channel wound around the first projecting magnetic poles. A winding, a second winding for the second channel wound around the second projecting magnetic pole, and a second core body having a C-shaped cross section disposed corresponding to the first core body and having a longitudinal shape A plurality of third and fourth projecting magnetic poles projecting inward at predetermined intervals along the longitudinal direction on both inner walls of the second core body, and the first wound around the third projecting magnetic poles A third winding for the channel and a fourth winding for the second channel wound around the fourth protruding magnetic pole, and each of the first and third protruding magnetic poles and the first and third windings. A first channel sensor is formed by windings, and a second channel sensor is formed by the second and fourth protruding magnetic poles and the second and fourth windings. A sum of output signals from the third and fourth windings when the first and second windings are excited by relative movement of the first and second core bodies, or 3. A configuration in which a linear position of the first core body or the second core body is detected using a sum of output signals from the first and second windings when the fourth winding is excited. The first core body is located in the recess of the second core body, and the first windings, the second windings, the third windings, The fourth windings are connected in series to each other or connected in parallel, and between the first protruding magnetic pole and each second protruding magnetic pole of the first core body. Are formed with cavities, and the first magnetic pole width of the first and second protruding magnetic poles of the first core body is the third and second of the second core body. The projecting magnetic pole is configured to be larger than the second magnetic pole width, and the second magnetic pole width is 1/3 or less of the first magnetic pole width, and the first and second projecting poles are configured. The magnetic poles and the third and fourth projecting magnetic poles are disposed symmetrically or asymmetrically along the longitudinal direction of the first and second core bodies, and the number of the first and second projecting magnetic poles and the third and fourth projecting magnetic poles are arranged. The number of the four protruding magnetic poles is the same or different.

Since the linear sensor according to the present invention is configured as described above, the following effects can be obtained.
That is, the projecting magnetic poles on both inner walls of the second core body having a square C-shaped cross section are provided on both sides of the first core body having a plurality of projecting magnetic poles on both sides so as to be relatively movable. As a channel sensor, windings are provided on each projecting magnetic pole so that the windings are arranged symmetrically with respect to the central axis in the detection direction to detect the linear position. Even when a tilt or the like occurs, the output voltage due to the movement in each direction increases or decreases depending on the overlapping state of the protruding magnetic poles of the first core body and the protruding magnetic poles of the second core body. The sum of voltage increases / decreases (synthesis) results in an output voltage that almost matches the above-mentioned state of each core body having no eccentricity and inclination, and as a result, the change in output voltage due to eccentricity and inclination is greatly reduced compared to the conventional case. High-precision linear position detection It can be carried out.
Moreover, since the cavity is formed between the projecting magnetic poles of the first core body having the projecting magnetic poles on both sides, magnetic interference (crosstalk) between the channels can be prevented.
In addition, since the first core body is located in the recess of the second core body having a U-shaped cross section, the thickness of the linear sensor can be made substantially the same as the thickness of the second core body. can do.

  In the present invention, a pair of channel sensors are formed by disposing the projecting magnetic poles of the second core body on both sides of the first core body having projecting magnetic poles and windings on both sides, and the sum of the output signals of the channel sensors is calculated. It is an object of the present invention to provide a linear sensor that detects an accurate linear position by reducing the influence of an attachment error such as an axis deviation or an inclination of each core body.

Hereinafter, preferred embodiments of a linear sensor according to the present invention will be described with reference to the drawings.
Note that the same or equivalent parts as in the conventional example will be described using the same reference numerals.
In FIG. 1 and FIG. 2, reference numeral 1 denotes a first core body that is formed in a longitudinal shape and laminated in a flat plate shape (a laminated core may be used instead of a laminated core). A plurality of first and second projecting magnetic poles 2 and 2A projecting in a direction perpendicular to the longitudinal direction A of the first core body 1 are integrally formed at predetermined intervals along the longitudinal direction A. .

The first and second projecting magnetic poles 2 and 2A are disposed via a slot 3, and the first core body 1 is provided at a substantially central position between the first and second projecting magnetic poles 2 and 2A, respectively. A cavity 10 penetrating through is formed.
The first and second windings 4 and 4A of the protruding magnetic poles 2 and 2A are used for the first and second channels, and are configured in the same manner as the windings of a well-known winding type resolver. Is derived to the outside.

  Magnetic interference (crosstalk) between the first and second windings 4 and 4A and the first and second projecting magnetic poles 2 and 2A is prevented by the cavity 10. The first windings 4 are connected to each other in series or in parallel, and the second windings 4A are connected to each other in series or in parallel.

  As shown in the cross-sectional view of FIG. 2, the first core body 1 has a long groove-like depression 11 formed along the longitudinal direction A of the second core body 6 having a C-shaped cross section. Located inside and housed.

The first and second inner walls 6a and 6b of the second core body 6 are provided with a plurality of first protrusions protruding inwardly at a predetermined interval along the longitudinal direction A and perpendicular to the longitudinal direction A. 3, fourth protruding magnetic poles 15 and 15A are formed.
A third winding 16 for the first channel is wound around the third protruding magnetic pole 15, and a fourth winding 16A for the second channel is wound around the fourth protruding magnetic pole 15A.

Similarly to the first and second windings 4 and 4A, the third winding 16 and the fourth winding 16A are connected to each other in series or in parallel with each other. The fourth windings 16A are connected to each other in series or in parallel.
Accordingly, the first channel sensor 20 is formed by the first protruding magnetic poles 2, the first windings 4, the third protruding magnetic poles 15, and the third windings 16, and the second protruding magnetic poles 2A, A second channel sensor 30 is formed by each second winding 4A, each fourth protruding magnetic pole 15A, and each fourth winding 16A.

The first magnetic pole width W ₁ along the longitudinal direction A of each of the first and second projecting magnetic poles 2, 2 A of the first core body ₁ is equal to the third and fourth projecting magnetic poles 15, 15 A of the second core body 6. is the formation from the longitudinal second pole width along the direction a W ₂ on a large, by way of example, in the configuration of FIG. 1, with is set to 3 times, W ₂ is less than 1/3 of W _1. The ratio of the width of the W ₂ and W ₁ are those that can be set arbitrarily.

  Next, in the above-described configuration, each of the first and second core bodies 1 and 6 can be a movable side or a fixed side. For example, the first core body 1 is not detected. A member (not shown) is connected, and the first core is fixed to the fixed second core body 6 in a state where an excitation signal is applied to the third and fourth windings 16 and 16A of the second core body 6. When the body 1 is linearly moved, the magnetic flux generated from the third and fourth projecting magnetic poles 15 and 15A moves in a state where the windings 4 and 4A of the projecting magnetic poles 2 and 2A cross each other, and The degree of magnetic coupling between the magnetic poles 2 and 2A and 15 and 15A changes, and the output signals (output voltages) from the first and second windings 4 and 4A on the output side are the same as those of a known winding type rotary resolver. Change.

In the case described above, the voltage level of the output signal changes according to the overlapping state of the first core 1 and the second core 6, and the output signal (output) output from the first and second windings 4 and 4A. For example, even if the central axis of the second core body 6 is eccentric or inclined with respect to the detection-direction central axis B of the first core body 1, As a result, the output signal (output voltage) substantially coincides with the state without the inclination, and as a result, the change in the voltage level of the output signal due to the eccentricity and inclination can be reduced as compared with the conventional example of FIG.
Each of the core bodies 1 and 6 has the first core body 1 as a fixed side, the second core body 6 as a movable side, and the first and second windings 4 and 4A as excitation sides, 3. The fourth windings 16 and 16A may be output.

In the above-described embodiment, the case where the protruding magnetic poles 2 and 2A and 15 and 15A are arranged symmetrically with respect to the detection direction central axis B and opposed to each other has been described. Without limiting to the form, each of the projecting magnetic poles 2 and 2A and each of the projecting magnetic poles 15 and 15A are not symmetrically arranged, but are configured to be asymmetrically shifted from each other along the detection direction central axis B, that is, the longitudinal direction A. You can also.
Each of the protruding magnetic poles 2, 2A, 15, 15A is composed of one or more integers, and each of the protruding magnetic poles 2, 2A, 15, 15A and each of the windings 4, 4A, 16, 16A is the longitudinal direction A, that is, the detection. They can be formed symmetrically with respect to the central axis B in the same number or asymmetrically with different numbers.
When the protruding magnetic poles 2 and 2A and 15 and 15A are arranged in asymmetrical and different numbers as described above, the number of turns and the distribution of windings of the windings 4, 4A and 16, 16A are changed, and each channel is changed. It is necessary to configure so that the sum of the output signals of the sensors 20 and 30 becomes the same output signal as when the above-mentioned symmetry and the same number.

It is a front view which shows the linear sensor by this invention. It is a cross-sectional view of FIG. It is a front view which shows the conventional linear sensor. It is a cross-sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st core body 2, 2A 1st, 2nd protrusion magnetic pole 3 Slot 4, 4A 1st, 2nd winding 5 Lead wire 6 2nd core body 6a, 6b 1st, 2nd inner wall 7, 7A 1st, Second concavo-convex portion 10 Cavity 11 Depressed portion 15, 15A Third and fourth projecting magnetic poles 16, 16A Third and fourth windings 20 First channel sensor 30 Second channel sensor A Longitudinal direction B Detection direction central axis W _1st 1 magnetic pole width W ₂ 2nd magnetic pole width

Claims (7)

A first core body (1) having a plurality of first and second projecting magnetic poles (2, 2A) projecting on both sides and having a longitudinal flat plate shape, and a first channel wound around the first projecting magnetic pole (2) Corresponding to the first winding (4) for the second channel, the second winding (4A) for the second channel wound around the second projecting magnetic pole (2A), and the first core body (1). A second core body (6) having a C-shaped cross section disposed and having a longitudinal shape, and both inner walls (6a, 6b) of the second core body (6) at predetermined intervals along the longitudinal direction (A). A plurality of third and fourth projecting magnetic poles (15, 15A) projecting inward, and a third winding (16) for the first channel wound around the third projecting magnetic pole (15), A fourth winding (16A) for the second channel wound around the fourth projecting magnetic pole (15A),
A first channel sensor (20) is formed by the first and third projecting magnetic poles (2, 15) and the first and third windings (4, 16).
A second channel sensor (30) is formed by the second and fourth projecting magnetic poles (2A, 15A) and the second and fourth windings (4A, 16A),
From the third and fourth windings (16, 16A) when the first and second windings (4, 4A) are excited by relative movement of the first and second core bodies (1, 6). Or the sum of output signals from the first and second windings (4, 4A) when the third and fourth windings (16, 16A) are excited, A linear sensor for detecting a linear position of a first core body (1) or a second core body (6).   The linear sensor according to claim 1, wherein the first core body (1) is located in a recess (11) of the second core body (6).   Are each of the first windings (4), each of the second windings (4A), each of the third windings (16), and each of the fourth windings (16A) connected in series? 3. The linear sensor according to claim 1, wherein the linear sensor is connected in parallel.   A cavity (10) is formed between each first projecting magnetic pole (2) and each second projecting magnetic pole (2A) of the first core body (1). Thru | or 3 linear sensor in any one. The first magnetic pole width (W 1) of the first and second projecting magnetic poles (2, 2A) of the first core body ( ₁ ) is the same as the third and fourth projecting magnetic poles (15) of the second core body (6). The linear sensor according to any one of claims 1 to 4, wherein the linear sensor is larger than the second magnetic pole width (W ₂ ) of 15A). 6. The linear sensor according to claim 1, wherein the second magnetic pole width (W ₂ ) is ３ or less of the first magnetic pole width (W ₁ ).   The first and second protruding magnetic poles (2, 2A) and the third and fourth protruding magnetic poles (15, 15A) are arranged along the longitudinal direction (A) of the first and second core bodies (1, 6). The number of the first and second protruding magnetic poles (2, 2A) and the number of the third and fourth protruding magnetic poles (15, 15A) are the same or different from each other. The linear sensor according to claim 1.

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