JP3264151B2 - Angle sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle sensor for a rotating body, and more particularly to a magnetic rotation angle sensor.

[0002]

2. Description of the Related Art Conventional magnetic rotation angle sensors include:
For example, there is one as shown in FIG. The annular magnetic member 35 having a constant cross section is magnetized so that the direction of the magnetic flux lines is diametrical at the reference position, and the magnetoelectric converter 36 is arranged at the center of the annular shape. As the magnetic member 35 and the magnetoelectric converter 36 rotate relatively,
The change in the rotation angle is detected by utilizing the fact that the component of the magnetic flux passing in the direction orthogonal to the magnetoelectric converter 36 changes.

[0003]

However, in such a conventional angle sensor, the magnetoelectric converter 36 has a circular magnetic shape with respect to the rotation angle due to the relative rotation with respect to the magnetic member 35. The cosine (cos θ) of the leakage magnetic flux density at the reference position of the member 35 with respect to the rotation angle (θ)
Since the component is detected, there is a problem that the range in which the change in the magnetic flux density passing through the magnetoelectric converter 36 changes linearly cannot be widened. The present invention has been made in view of such problems of the prior art,
It is an object of the present invention to provide an angle sensor suitable for obtaining a linear output according to a wide range of angle change of a rotating body.

[0004]

Means for solving the above problems are described in the claims. The present invention provides two arc- shaped permanent magnets that generate a same magnetic flux by juxtaposing magnetized poles at a predetermined distance so that the same poles face each other,
A leakage magnetic flux concentrating means of a soft magnetic material provided in a space surrounded by the two arc- shaped permanent magnets, a magnetoelectric converter disposed at a central portion of the leakage magnetic flux concentrating means, and the arc-shaped permanent magnet or the magnetic flux A rotating mechanism for rotating one of the concentrating means forward and reverse with respect to the other, and detecting a change in magnetic flux flowing through the leaked magnetic flux concentrating means via the magnetoelectric converter, so that the arc-shaped permanent magnet and the The angle sensor detects the magnitude of the relative rotation angle change of the magnetic flux concentration means and the forward / reverse direction of the rotation.

[0005] For example, as shown in FIG. 6, two arc-shaped permanent magnet 2 is the magnetic field generator that is disposed at a predetermined distance so that identical poles face each other, an arc-shaped permanent magnet 1, Magnetic flux concentrating means (yoke) 4, 5 made of soft magnetic material for collecting the magnetic flux leaking from the arc-shaped permanent magnet in the space surrounded by 2, and are arranged at the center of the magnetic flux concentrating means 4, 5. It constitutes a detection part of a magnetic angle sensor composed of a magnetoelectric converter 3 and an arc-shaped permanent magnet 1, 2 or
It has a rotation mechanism for rotating either one of the magnetic flux concentrating means 4 and 5, and the change in the relationship between the permanent magnets 1 and 2 and the magnetic flux concentrating means 4 and 5 causes The output is obtained using the change. With this configuration, an angle sensor having excellent linearity output over a wide range of rotation angles of the rotating body can be obtained.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Reference Example 1> FIG 1 is a diagram showing a reference example 1 of the present invention. First, the configuration will be described. Reference numerals 1 and 2 denote columnar permanent magnets having the same shape and generating substantially the same magnetic flux, and are magnetized in the longitudinal direction of the columnar body. Reference numeral 3 denotes a magnetoelectric converter for detecting a magnetic flux density, and reference numerals 4 and 5 denote magnetic flux concentrating means, that is, yokes made of a soft magnetic material having the same shape and the same magnetic characteristics.

The permanent magnets 1 and 2 have the same polarity, that is, the N poles or the S poles are opposed to each other, and the permanent magnets 1 and 2 are parallel to each other with an interval slightly larger than the longitudinal dimension. It is arranged in. The yokes 4, 5 are permanent magnets 1 ,
The magneto-electric converter 3 is disposed on a straight line in the center of the space surrounded by the center 2, and is provided at the center of the yokes 4 and 5. Further, a rotation mechanism is provided for rotating any one of the permanent magnets 1 and 2 or the yokes 4 and 5 about a point a in the drawing. This makes it possible to provide a rotational movement that causes a change in the relative angle between the permanent magnets 1 and 2 and the yokes 4 and 5.

FIG. 2 shows a magnetic flux line 6 when the magnetoelectric converter 3 and the yokes 4 and 5 are located on a line connecting the centers of the permanent magnets 1 and 2 (a reference position at a rotation angle of 0 °).
The state and the direction of are shown. In this state, since the magnetic flux lines 6 do not flow through the yoke 5 from the yoke 4, the magnetic flux density detected by the magnetoelectric converter 3 is zero.

Next, the yokes 4 and 5 rotate clockwise from the state shown in FIG. 2 to the state shown in FIG. 3, so that the end of the yoke 4 is the N pole of the permanent magnet 1 and the end of the yoke 5 is the permanent magnet. When approaching the S pole of the magnet 2, the magnetic flux lines 7 enter from the yoke 4 and flow toward the yoke 5, and accordingly, the magnetoelectric converter 3 changes according to the magnitude of the magnetic flux density between the yokes 4 and 5. Produces a positive output.

Conversely, the yokes 4 and 5 rotate counterclockwise, so that the end of the yoke 4 is at the S pole of the permanent magnet 1 and the end of the yoke 5 is the When approaching the N pole, the magnetic flux lines 8 enter from the yoke 5 and enter the yoke 4.
, And the magnetoelectric converter 3 generates a negative output according to the magnitude of the magnetic flux density between the yokes 4 and 5. As described above, the change in the magnetic flux density flowing between the yokes 4 and 5 due to the relative rotation of the permanent magnets 1 and 2 and the yokes 4 and 5 is converted into a linear output as a positive or negative value. Detecting by using the converter 3 makes it possible to obtain approximately ± 45
An output corresponding to a change in the rotation angle can be obtained in the range of degrees.

FIG. 5 is a characteristic diagram showing the relationship between the magnetic flux density and the rotation angle, detected by an angle sensor using the reference example 1 as a detection portion. It changes almost linearly in the angle range of approximately -45 degrees to +45 degrees, so that the magnetoelectric converter 3 can obtain an output of an angle change excellent in linearity over a wide angle. In the first embodiment, since the columnar permanent magnet is used for the magnetic flux generating means, the angle sensor can be provided at low cost.

< First Embodiment> FIG. 6 is a diagram showing a first embodiment. In FIG.
1 are denoted by the same reference numerals. This embodiment, the basic action in Reference Example 1 shown in FIG. 1
The difference is that the permanent magnets 9 and 10 are formed in an arc shape in order to linearly change the magnetic flux density flowing through the yokes 4 and 5 over a wider angle. In FIG. 6, the shape of the permanent magnets 9 and 10 forms an arc concentric with the arc of the locus on which the yokes 4 and 5 rotate, but the shape of the permanent magnets depends on the output characteristics of the magnetoelectric converter 3 with respect to the rotation angle. The curvature of the arc formed by the magnets 9 and 10 may be changed. In the present embodiment, since an arc-shaped permanent magnet is used for the magnetic flux generating means, an output having excellent linearity over a wider angle can be obtained as compared with Reference Example 1, and the amount of change in the detected magnetic flux density can be increased. Therefore, the size of the permanent magnet can be reduced and the size of the angle sensor can be reduced.

Second Embodiment FIG. 7 is a diagram showing a second embodiment, in which the same parts as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the basic operation is the same as that of the reference example 1 shown in FIG. 1, and the difference is that the permanent magnets 11 and 12 and the permanent magnets 13 and 14 are used instead of the two columnar permanent magnets. ,
The point is that two soft magnetic materials 15 and 16 are arranged between the permanent magnets 11 and 12 and the permanent magnets 13 and 14 as magnetic flux transmitting means. This embodiment, since a small size to the permanent magnet as a magnetic flux generating means can be used, it is possible to reduce costs further angle sensor as compared with Reference Example 1.

<Reference Example 2> FIG. 8 is a view showing Reference Example 2 , in which the same parts as those in FIG. 1 are denoted by the same reference numerals. This reference example
2 has the same basic operation as that of the reference example 1 shown in FIG. 1, and is different from the first embodiment in that two permanent magnets are used instead of the two columnar permanent magnets.
At a predetermined distance so that the same poles face each other,
The point is that soft magnets 19, 20, 21, and 22 are arranged as magnetic flux transmitting means on the magnetized surfaces of two permanent magnets 17 and 18 having magnetized poles .

Third Embodiment FIG. 9 is a diagram showing a third embodiment, in which the same parts as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the basic operation is similar to that of the second embodiment shown in FIG.
The difference is that the soft magnetic materials 27 and 28 are formed in an arc shape in order to linearly change the magnetic flux density between the yokes 4 and 5 over a wider angle than in the second embodiment. Is a point. This embodiment is an embodiment
In the second embodiment, an arc-shaped soft magnetic material disposed between the permanent magnets is used, so that an output having excellent linearity over a wide angle can be obtained as compared with the second embodiment.

Fourth Embodiment FIG. 10 is a diagram showing a fourth embodiment, in which the same parts as those in FIG. 1 are denoted by the same reference numerals. The basic operation of this embodiment is the same as that of the reference example 2 shown in FIG. 8, and the difference is that the magnetic flux density between the yokes 4 and 5 is linearly increased over a wider angle than in the reference example 2. The point is that the shapes of the soft magnetic materials 31, 32, 33, and 34 are formed in an arc shape in order to change them. This embodiment is a reference
Since an arc-shaped soft magnetic material was arranged on each of the magnetized surfaces of the two permanent magnets in Example 2 , an output excellent in linearity over a wide angle was obtained as compared with Reference Example 2, and the third embodiment was performed.
The number of permanent magnets to be used can be reduced as compared with, and the cost can be further reduced as compared with the third embodiment.

[0017]

According to the present invention, two magnetic flux generating means having magnetized poles disposed at a predetermined distance so that the same poles face each other, and a magnetic flux generating means in a space surrounded by the magnetic flux generating means. Magnetic flux generating means, or magnetic flux concentrating means, as two magnetic flux concentrating means made of a soft magnetic material for collecting magnetic flux leaking from the magnetic flux sensor and a magnetic type angle sensor consisting of a magnetoelectric converter arranged at the center of the magnetic flux concentrating means. Because of the configuration having a rotation mechanism for rotating one of the means, the relative positional relationship between the magnetic flux generating means and the magnetic flux concentrating means changes, so that the magnitude of the magnetic flux passing through the magnetoelectric converter changes, and Since the converter generates an output in accordance with the magnitude of the magnetic flux density, the absolute value of the rotation angle of the rotating object can be measured in a non-contact manner within a range of approximately ± 45 degrees. In which an effect that the output linearity of excellent magneto-electric transducer can be obtained over time.

[Brief description of the drawings]

1 is a basic configuration diagram showing a reference example 1 of the present invention.

FIG. 2 is a view showing the operation of Reference Example 1 of the present invention.

FIG. 3 is a view showing the operation of Reference Example 1 of the present invention.

FIG. 4 is a view showing the operation of Reference Example 1 of the present invention.

5 is an output characteristic diagram of the angle sensor according to Example 1 of the present invention.

FIG. 6 is a basic configuration diagram showing the first embodiment of the present invention.

FIG. 7 is a basic configuration diagram showing a second embodiment of the present invention.

FIG. 8 is a basic configuration diagram showing Reference Example 2 of the present invention.

FIG. 9 is a basic configuration diagram showing a third embodiment of the present invention.

FIG. 10 is a basic configuration diagram showing a fourth embodiment of the present invention.

FIG. 11 is a plan view and a perspective view of a conventional magnetic angle sensor.

[Explanation of symbols]

1-2, 9-14, 17-18, 23-26, 29-3
0: permanent magnet 3, 36: magnetoelectric converter 4-5, 15-16, 19-22, 27-28, 31-
34: Soft magnetic material 6-8: Magnetic flux line 35: Magnetic member 36: Magnetoelectric converter 37: Rotating shaft

Claims (4)

(57) [Claims] 1. An arc- shaped permanent magnet which generates a same magnetic flux by arranging magnetized poles at a predetermined distance so that the same poles are opposed to each other, and in a space surrounded by the two arc- shaped permanent magnets. The provided leakage magnetic flux concentration means of the soft magnetic material, the magnetoelectric converter arranged at the center of the leakage magnetic flux concentration means, and rotating one of the arc-shaped permanent magnet or the magnetic flux concentration means forward and reverse with respect to the other. Having a rotation mechanism, by detecting a change in magnetic flux flowing through the leakage magnetic flux concentration means through the magnetoelectric converter, the magnitude and rotation of the relative rotation angle change of the arc-shaped permanent magnet and the magnetic flux concentration means An angle sensor for detecting forward and reverse directions. 2. A permanent magnet which has the same magnetization direction and generates the same magnetic flux is disposed at both ends of two opposing arcuate soft magnetic materials in place of said two arcuate permanent magnets. The angle sensor according to claim 1 , wherein: 3. An arc-shaped soft magnetic material is disposed at both ends of two permanent magnets arranged in parallel at a predetermined distance and having the same magnetization direction , instead of the two arc-shaped permanent magnets. The angle sensor according to claim 1 , wherein 4. Both ends of two opposing columnar soft magnetic materials are magnetized.
Permanent magnets that generate the same magnetic flux in the same direction
The structure is placed in a space surrounded by the two columnar soft magnetic materials and permanent magnets.
Means for concentrating leakage magnetic flux of a soft magnetic material, and a magnetoelectric converter disposed at the center of the means for concentrating leakage magnetic flux
And one of the structure or the magnetic flux concentrating means
And a rotation mechanism for rotating forward and backward, and flows through the leakage magnetic flux concentration means via the magnetoelectric converter.
The Rukoto to detect a change in that magnetic flux, the said structure
Magnitude of relative rotation angle change and forward / reverse rotation of magnetic flux concentration means
An angle sensor for detecting a direction .