JP2009025317A - Rotation angle detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of errors in detecting rotation angles, even when the set position of a magnetic detection element is misaligned in the x-axis direction, by eliminating the decrease or increase of the magnetic flux density passing through the magnetic detection element due to the misalignment. <P>SOLUTION: A flux projecting magnet 6 and a flux receiving magnet 7 are made up so that the thickness along the arc direction, when viewed from z-axis direction, is thick at the center of the arc B1 and thin at the ends of the arc B2. Therefore, the distances from the inner peripheral surfaces of the flux projecting magnet 6 and flux receiving magnet 7 to a Hall element 2 become gradually larger toward the ends B2. Even when the Hall element 2 is misaligned in the x-axis direction due to assembling errors, changes in the magnetic flux density passing through the Hall element 2 due to the misalignment can be lost by the flux projecting magnet 6 and the flux receiving magnet 7 which are made thinner in the misaligned direction, and the errors in detecting the rotation angles can be prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device that detects a relative rotation angle between two members (for example, a rotation member and a non-rotation member).

(Conventional technology)
A schematic structure of a conventional rotation angle detection device will be described with reference to FIGS.
The rotation angle detection device provides a magnetic detection element J1 (for example, a Hall element incorporated in the Hall IC) disposed on a rotation axis (hereinafter referred to as the Z-axis) and applies a magnetic flux toward the magnetic detection element J1. A semi-cylindrical magnetic flux applying magnet J2 and a semi-cylindrical magnetic flux attracting magnet J3 for attracting a magnetic flux applied from the magnetic flux applying magnet J2 toward the magnetic detecting element J1 are provided.
The magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3 are fixed to the inner peripheral surface of the yoke J4 having a cylindrical shape, and the thickness in the direction perpendicular to the Z axis, that is, the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3. The thickness of was constant.
On the other hand, the magnetic detection element J1 is supported in a state surrounded by the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3.

When the relative rotation angle between the magnetic flux generating means (the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3) and the magnetic detection element J1 changes, the magnetic flux density in the direction perpendicular to the magnetic detection surface of the magnetic detection element J1 changes.
Specifically, the magnetic flux is generated from the relative rotation angle shown in FIG. 21A (this rotation angle is 0 °) to the relative rotation angle shown in FIG. 21B (this rotation angle is 90 °). By rotating the means, the magnetic flux density in the direction orthogonal to the magnetic detection surface of the magnetic detection element J1 changes as shown in FIG.
Since the magnetic detection element J1 generates an output signal corresponding to the magnetic flux density in the direction orthogonal to the magnetic detection surface, the rotation angle detection device is connected to the magnetic flux generation means side member based on the output signal of the magnetic detection element J1. The relative rotation angle with the member on the magnetic detection element J1 side can be detected (see, for example, Patent Documents 1 to 4).

(Trouble of conventional technology)
The conventional rotation angle detection device that employs the above configuration has the following problems.
(1) For example, when the installation position of the magnetic detection element J1 is shifted in the magnetic insensitive direction (hereinafter referred to as the X-axis direction) of the magnetic detection element J1 with the rotation angle of 90 ° shown in FIG. The distances between the applying magnet J2 and the magnetic flux attracting magnet J3 and the magnetic detection element J1 approach each other. Then, with respect to the ideal magnetic flux density shown in the broken line in FIG. 23 (the magnetic flux density that does not change even if the installation position of the magnetic detection element J1 is shifted in the X-axis direction), as shown by the solid line A ′ in FIG. The magnetic flux density passing through the detection element J1 increases.
As described above, when the set position of the magnetic detection element J1 is shifted in the X-axis direction due to an error during assembly or the like, the magnetic flux density passing through the magnetic detection element J1 increases, and an output exceeding a predetermined value is output from the magnetic detection element J1. Occurs, and a rotation angle detection error occurs.

(2) In the above, the example in which the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3 are each constituted by one magnet has been shown. On the other hand, as shown in FIG. 24, each of the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3 is composed of two flat magnets and arranged in a substantially arc shape in the rotational direction when viewed from the Z-axis direction. explain.
In this case, when the installation position of the magnetic detection element J1 is shifted in the X-axis direction of the magnetic detection element J1 with the rotation angle of 90 ° shown in FIG. 24, the magnetic flux application magnet J2 and the magnetic flux attracting magnet J3 The distance to element J1 approaches. Then, as in (1) above, the magnetic flux density passing through the magnetic detecting element J1 increases as shown by the solid line A ′ in FIG. 23 with respect to the ideal magnetic flux density shown in the broken line in FIG.
As described above, when the set position of the magnetic detection element J1 is shifted in the X-axis direction due to an error during assembly or the like, the magnetic flux density passing through the magnetic detection element J1 increases, and an output exceeding a predetermined value is output from the magnetic detection element J1. Occurs, and a rotation angle detection error occurs.

(3) Further, as shown in FIG. 25, a case will be described in which each of the magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3 is constituted by one flat magnet and arranged in parallel when viewed from the Z-axis direction. The magnetic flux applying magnet J2 and the magnetic flux attracting magnet J3 have a large leakage flux at both ends in the X-axis direction. For this reason, if the installation position of the magnetic detection element J1 shifts in the X-axis direction in the state of the rotation angle of 90 ° shown in FIG. 25A, the position of the magnetic detection element J1 moves to the side where the leakage magnetic flux is large. That is, for the ideal magnetic flux density indicated by the broken line in FIG. 26 (the magnetic flux density that does not change even if the installation position of the magnetic detection element J1 is shifted in the X-axis direction), as shown by the solid line B ′ in FIG. The density of the magnetic flux passing through the magnetic detection element J1 decreases as the installation position of the detection element J1 deviates from the center in the X-axis direction.
As described above, when the set position of the magnetic detection element J1 is shifted in the X-axis direction due to an error during assembly, the magnetic flux density passing through the magnetic detection element J1 is reduced, and a predetermined output is output from the magnetic detection element J1. As a result, the rotation angle detection error occurs.

(4) The magnetic flux application magnet J2 and the magnetic flux attracting magnet J3 have a large leakage flux at both ends in the Z-axis direction. For this reason, for example, in the state shown in FIG. 20B, if the installation position of the magnetic detection element J1 is shifted in the Z-axis direction, the position of the magnetic detection element J1 moves to the side where the leakage magnetic flux is large. That is, for the ideal magnetic flux density indicated by the broken line in FIG. 27 (the magnetic flux density that does not change even if the installation position of the magnetic detection element J1 is shifted in the Z-axis direction), as shown by the solid line C ′ in FIG. When the installation position of the detection element J1 is shifted from the center in the Z-axis direction, the magnetic flux density passing through the magnetic detection element J1 is lowered.
As described above, when the set position of the magnetic detection element J1 is shifted in the Z-axis direction due to an error during assembly, the magnetic flux density passing through the magnetic detection element J1 is reduced, and a predetermined output is output from the magnetic detection element J1. As a result, the rotation angle detection error occurs.
Japanese Patent No. 3206204 JP-A-2-122205 JP-A-2-298815 JP-A 64-37607

The present invention has been made in view of the above circumstances, and has the following objects.
The purpose (first object) is to eliminate the increase or decrease of the magnetic flux density passing through the magnetic detection element due to the deviation even when the installation position of the magnetic detection element is shifted in the X-axis direction. Prevents detection errors.
As another object (second object), even if the installation position of the magnetic detection element is further shifted in the Z-axis direction, the occurrence of a rotation angle detection error is prevented. That is, even if the installation position of the magnetic detection element is shifted in the Z-axis direction or the installation position of the magnetic detection element is shifted in the X-axis direction, the occurrence of a rotation angle detection error is prevented.

[Means of Claim 1]
In the rotation angle detection apparatus employing the means of claim 1, when the magnetic flux applying magnet and the magnetic flux attracting magnet have an arc shape along the rotational direction when viewed from the Z-axis direction, at least one of the magnetic flux applying magnet and the magnetic flux attracting magnet. The thickness seen from the Z-axis direction is such that the center is thick and the end side is thin.
By providing in this way, when the installation position of the magnetic detection element is shifted in the X-axis direction, a magnet (at least one of a magnetic flux applying magnet and a magnetic flux attracting magnet) having a thin end side is used to shift the magnetic detection element due to the shift. It is possible to eliminate an increase in the density of magnetic flux passing therethrough, and as a result, it is possible to prevent occurrence of a rotation angle detection error.
That is, the first object can be achieved.

[Means of claim 2]
In the rotation angle detection device employing the means of claim 2, when the magnetic flux applying magnet and the magnetic flux attracting magnet are arranged in parallel when viewed from the Z axis direction, at least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is in the Z axis direction. From the viewpoint of thickness, the center is thin and the end side is thick.
By providing in this way, when the installation position of the magnetic detection element is shifted in the X-axis direction, the magnetism detection element due to the shift is caused by a magnet (at least one of a magnetic flux applying magnet and a magnetic flux attracting magnet) that is thick in the shifted direction. As a result, it is possible to prevent a decrease in the rotational angle detection error.
That is, the first object can be achieved.

[Means of claim 3]
The rotation angle detecting device adopting the means of claim 3 is provided in the case where the magnetic flux applying magnet and the magnetic flux attracting magnet are arranged in parallel with the Z axis and in parallel when viewed from the Z axis direction. The thickness along the Z-axis direction of at least one of the attraction magnets is provided so that the periphery of the setting position of the magnetic detection element is thin and the side away from the setting position of the magnetic detection element is thick, and at least one Z of the magnetic flux applying magnet and the magnetic flux attraction magnet The thickness viewed from the axial direction is such that the center is thin and the end side is thick.

By providing in this way, when the installation position of the magnetic detection element is shifted in the Z-axis direction, the magnetism detection element due to the shift is generated by a magnet (at least one of a magnetic flux applying magnet and a magnetic flux attracting magnet) that is thick in the shifted direction. As a result, it is possible to prevent a decrease in the rotational angle detection error.
Further, when the installation position of the magnetic detection element is shifted in the X-axis direction, the magnetic flux density passing through the magnetic detection element due to the shift is increased by a magnet (at least one of a magnetic flux applying magnet and a magnetic flux attracting magnet) thickened in the shifted direction. The decrease can be eliminated, and as a result, the occurrence of a rotation angle detection error can be prevented.
That is, the second object can be achieved.

[Means of claim 4]
The magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 4 are each constituted by one magnet having a semi-cylindrical shape, and are substantially divided in the diameter direction by the magnetic flux applying magnet and the magnetic flux attracting magnet. It exhibits a cylindrical shape.

[Means of claim 5]
The magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detection device adopting the means of claim 5 are each configured by arranging a plurality of magnets arranged in an arc shape in the rotation direction when viewed from the Z-axis direction. It is.

[Means of claim 6]
The magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 6 are each constituted by one magnet, arranged in parallel with the Z axis, and arranged in parallel when viewed from the Z axis direction. Is.

[Means of Claim 7]
In the rotation angle detecting device employing the means of claim 7, when the magnetic detection element is installed at the center in the Z-axis direction of the magnetic flux generating means, the thickness along the Z-axis direction of at least one of the magnetic flux applying magnet and the magnetic flux attracting magnet. The center in the Z-axis direction is thin, and both end sides in the Z-axis direction are thick.

[Means of Claim 8]
The change in the thickness along the Z-axis direction of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 8 is provided only in the central portion in the Z-axis direction.

[Means of Claim 9]
The change in the thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 9 changes according to the change of the magnetic flux density passing through the magnetic detecting element that changes according to the shift of the installation position of the magnetic detecting element. It is provided based on the width.

[Means of Claim 10]
The change in the thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device employing the means of claim 10 is provided with the inner surface recessed.

[Means of Claim 11]
The change in the thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device employing the means of claim 11 is provided with the outer surface recessed.

[Means of Claim 12]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 12 is such that the inner surface viewed from the direction of the rotation axis is provided on a curved surface having a multi-order curve.

[Means of Claim 13]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device employing the means of claim 13 is such that the outer surface viewed from the rotation axis direction is provided on a curved surface having a multi-order curve.

[Means of Claim 14]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotational angle detection device employing the means of claim 14 has an inner surface viewed from the rotational axis direction on a curved surface having a multi-order curve, and viewed from the rotational axis direction. The outer surface is provided on a curved surface having a multi-order curve.

[Means of Claim 15]
The multi-degree curve of at least one of the inner surface and the outer surface as viewed from the direction of the rotation axis of the rotation angle detecting device employing the means of claim 15 is different in the left and right curvature changes as viewed from the direction of the rotation axis, and is provided left-right asymmetrically. It is.

[Means of claim 16]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 16 has an inner surface along the rotation axis direction provided on a curved surface having a multi-order curve.

[Means of Claim 17]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detecting device adopting the means of claim 17 is such that the outer surface along the rotation axis direction is provided on a curved surface having a multi-order curve.

[Means of Claim 18]
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet of the rotation angle detection device employing the means of claim 18 has an inner surface along the rotation axis direction provided on a curved surface having a multi-order curve, and an outer surface along the rotation axis direction. Are provided on a curved surface having a multi-order curve.

[Means of Claim 19]
21. A multi-degree curve of at least one of an inner surface and an outer surface along the rotation axis direction of the rotation angle detection device employing the means of claim 19 is a left-right curvature change of a set position of the magnetic detection element viewed from a direction orthogonal to the rotation axis. However, they are provided asymmetrically with reference to the set position of the magnetic detection element viewed from the direction orthogonal to the rotation axis.

The best mode of the present invention will be described using a plurality of embodiments and modifications.
Examples 1 and 2 are examples corresponding to the first invention (Claim 1), Example 3 is an example corresponding to the second invention (Claim 2), and Examples 4 to 8 are This is an embodiment corresponding to the third invention (Claim 3).
Examples 9-12 are examples corresponding to claims 12-19.

A first embodiment will be described with reference to FIGS. First, the basic configuration of the rotation angle detection device will be described with reference to FIG. 1A is a view of the rotation angle detection device viewed from the Z-axis direction, and FIG. 1B is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
The rotation angle detection device shown in this embodiment is for detecting the rotation angle (opening degree) of a throttle valve, for example, and a rotor 1 (rotation member) that rotates integrally with a throttle valve via a member (not shown). And Hall IC 3 incorporating Hall element 2 (an example of a magnetic detection element). The Hall IC 3 is supported by a fixing member (non-rotating member) (not shown), and the Hall element 2 is disposed on the Z axis of the rotor 1.

The rotor 1 is arranged concentrically around the Hall IC 3 and includes a yoke 4 having a cylindrical shape and magnetic flux generation means 5 that generates a magnetic flux passing through the Hall IC 3.
The magnetic flux generation means 5 includes a magnetic flux applying magnet 6 that applies a magnetic flux to the Hall element 2 and a magnetic flux attracting magnet 7 that attracts the magnetic flux applied from the magnetic flux applying magnet 6 toward the Hall element 2. That is, the inner peripheral surface of the magnetic flux applying magnet 6 is arranged so as to have an N-pole polarity, and the inner peripheral surface of the magnetic flux attracting magnet 7 is arranged so as to have an S-pole polarity.

  The magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are arranged opposite to each other with a distance on both sides of the Hall element 2. The magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 of this embodiment each have a semi-cylindrical shape, and have a substantially cylindrical shape divided in the diameter direction by the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7. A predetermined air gap is formed at a portion where the arc ends of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 face each other. The magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are fixed inside the yoke 4 and are disposed so as to surround the Hall element 2.

  The Hall IC 3 concentrically disposed at the center of the rotor 1 is a well-known IC in which the Hall element 2 and a signal processing circuit are integrated, and the magnetic flux density in the direction orthogonal to the magnetic detection surface of the Hall element 2 A voltage signal corresponding to is output.

The operation of the rotation angle detection device having the above configuration will be described with reference to FIG.
In the following, as shown in FIG. 1, the rotation axis of the rotor 1 is the Z axis, and the magnetic insensitive direction (direction along the magnetic detection surface) of the Hall element 2 is defined as X in the direction orthogonal to the Z axis. In the following description, the axis is the direction perpendicular to the Z axis, and the magnetic detection direction of the Hall element 2 (the direction perpendicular to the magnetic detection surface) is the Y axis.
Here, the rotation angle of the rotor 1 in which the center of the air gap between the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 faces in the Y-axis direction is 0 °, and the air gap between the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 The rotation angle of the rotor 1 whose center is oriented in the X-axis direction is 90 ° (see FIG. 1).

In the rotation angle detection device, a magnetic circuit is formed in which magnetic flux flows through a path of magnetic flux applying magnet 6 → Hall IC 3 (Hall element 2) → Flux attracting magnet 7. When the rotor 1 rotates together with the throttle valve, the magnetic flux orthogonal to the magnetic detection surface of the hall element 2 changes.
That is, as shown in FIG. 1A, when the center of the air gap between the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is in the position (rotation angle 90 °) in the X-axis direction, the magnetic detection of the Hall element 2 is detected. The magnetic flux density orthogonal to the surface is maximized, and even if the rotation angle of the rotor 1 increases from 90 ° or conversely decreases from 90 °, it is orthogonal to the magnetic detection surface of the Hall element 2 depending on the rotation angle. The amount of magnetic flux decreases.
Then, at the position where the center of the air gap between the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 faces in the Y-axis direction (rotation angle 0 °), the magnetic flux orthogonal to the magnetic detection surface of the Hall element 2 becomes zero.

Furthermore, when the rotation angle rotates to the minus side from 0 °, the amount of magnetic flux in the opposite direction perpendicular to the magnetic detection surface of the Hall element 2 increases according to the rotation angle. When the rotation angle of the rotor 1 is −90 °, the magnetic flux density in the reverse direction orthogonal to the magnetic detection surface of the Hall element 2 is maximized.
When the rotation angle rotates further to the minus side than −90 °, the amount of magnetic flux in the opposite direction perpendicular to the magnetic detection surface starts to decrease according to the rotation angle, and the reverse magnetic flux density passing through the Hall element 2 decreases. .

[Features of Example]
In a rotation angle detection device that detects the opening of a throttle valve, there is a need to detect a minute opening (near idling) with high accuracy, and therefore, the vicinity of a magnetic flux density of 0 may be used as the 0 ° position of the throttle valve. . For this reason, the rotation angle detection device for detecting the opening degree of the throttle valve is normally used in a rotation angle range of 0 ° to 90 °.

  As described in (1) of the background art section, when the installation position of the Hall element 2 is shifted in the X-axis direction in a state where the rotation angle of the rotor 1 is 90 °, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 Since the distance from the Hall element 2 approaches, the magnetic flux density passing through the Hall element 2 increases (see solid line A ′ in FIG. 3). For this reason, when the setting position of the Hall element 2 is shifted in the X-axis direction due to an error during assembly, the magnetic flux density passing through the Hall element 2 is increased, and an output of a predetermined level or more is generated from the Hall element 2. This will cause a detection error of the rotation angle.

  Therefore, in Example 1, in order to solve the above-described problem, the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 viewed from the Z-axis direction, that is, the thickness along the arc direction (synonymous with the rotation direction) is shown in FIG. As shown in (a), the center B1 in the arc direction is thick and the end B2 side in the arc direction is thin. Thus, the distance between the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 and the Hall element 2 is configured to gradually increase toward the end B2. The change in the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is set based on the change width of the magnetic flux density passing through the Hall element 2 that changes according to the installation position of the Hall element 2 being shifted in the X-axis direction. The That is, the magnetic flux density passing through the Hall element 2 is set so as not to change even if the installation position of the Hall element 2 is shifted in the X-axis direction.

The rotation angle detection device of the present embodiment is provided as described above, so that the installation position of the Hall element 2 becomes X from the center of the magnetic flux application magnet 6 and the magnetic flux attraction magnet 7 due to an assembly error of the rotation angle detection device. Even if it shifts in the axial direction, the increase in magnetic flux density passing through the Hall element 2 due to the shift can be eliminated by the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 which are thinned in the shifted direction. Specifically, as shown by a solid line A in FIG. 3, the magnetic flux density does not increase even when the installation position of the Hall element 2 is shifted from the center in the X-axis direction, and an almost ideal magnetic flux density can be obtained.
That is, because the magnetic flux density does not change even if the installation position of the Hall element 2 is shifted in the X-axis direction due to an assembly error of the rotation angle detection device, the occurrence of a rotation angle detection error can be prevented.

  In Example 1, as a means for thinning the end B2 in the arc direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7, the shape (the inner surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is shaved. Although the example provided in the recessed shape) is shown, conversely, the same effect can be obtained even if the outer peripheral surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is sharpened (the outer surface is recessed). Obtainable.

  In the first embodiment, the thickness of both the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is changed. However, only one of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 may be changed in thickness. . For example, as shown in FIG. 4, only one of the magnetic flux applying magnet 6 or the magnetic flux attracting magnet 7 is provided with a thick center B1 in the arc direction and a thin end B2 in the arc direction. A thickness along the other arc direction may be constant. That is, the curvatures on the Z-axis side of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 may be changed. Even if it provides in this way, the same effect can be acquired.

Example 2 will be described with reference to FIG. FIG. 5A is a view of the rotation angle detection device viewed from the Z-axis direction, and FIG. 5B is a cross-sectional view of the rotation angle detection device along the Z-axis direction. In addition, the same code | symbol as Example 1 in this Example 2 or later shows the same function thing unless it adds special description.
In each of the above embodiments, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 having a semi-cylindrical shape are shown as examples. On the other hand, in the second embodiment, as shown in FIG. 5A, the magnetic flux applying magnets 6 are combined with a plurality of (in this embodiment, two) magnets 6a to form a substantially arc shape when viewed from the Z-axis direction. The magnetic flux attracting magnets 7 are also arranged so as to form a substantially arc shape when viewed from the Z-axis direction by combining a plurality of (two in this embodiment) magnets 7a.

  As described in (2) of the background art section, when the installation position of the Hall element 2 is shifted in the X-axis direction in a state where the rotation angle of the rotor 1 is 90 °, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 Since the distance from the Hall element 2 approaches, the magnetic flux density passing through the Hall element 2 increases (see solid line A ′ in FIG. 3). For this reason, when the setting position of the Hall element 2 is shifted in the X-axis direction due to an error during assembly, the magnetic flux density passing through the Hall element 2 is increased, and an output of a predetermined level or more is generated from the Hall element 2. This will cause a detection error of the rotation angle.

  Therefore, in this second embodiment, in order to solve the above-described problem, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 each constituted by two magnets 6a and 7a are respectively shown in FIG. As shown in (a), the center B1 in the rotational direction is thick and the end B2 side in the rotational direction is thin. That is, the distance between the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 and the Hall element 2 is configured to gradually increase toward the end B2 in the rotational direction. Changes in the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 each composed of two magnets 6a and 7a pass through the Hall element 2 that changes in accordance with the installation position of the Hall element 2 being shifted in the X-axis direction. It is set based on the change width of the magnetic flux density. That is, the magnetic flux density passing through the Hall element 2 is set so as not to change even if the installation position of the Hall element 2 is shifted in the X-axis direction.

The rotation angle detection device of the present embodiment is provided as described above, so that the installation position of the Hall element 2 is X from the center of the magnetic flux applying magnet 6 and the magnetic flux attraction magnet 7 due to an assembly error of the rotation angle detection device. Even if it shifts in the axial direction, the magnetic flux application magnet 6 and the magnetic flux attracting magnet 7 that are thin in the shifted direction can eliminate the increase in the magnetic flux density that passes through the Hall element 2 due to the shift. Specifically, as shown by the solid line A in FIG. 3 shown in the first embodiment, the magnetic flux density does not increase even if the installation position of the Hall element 2 is shifted from the center in the X-axis direction. Obtainable.
That is, as in the first embodiment, the magnetic flux density does not decrease even if the installation position of the Hall element 2 is shifted in the X-axis direction due to an assembly error of the rotational angle detection device, etc., thus preventing the rotational angle detection error from occurring. Can do.

In the second embodiment, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet are used as means for thinning the end B2 in the rotational direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 each composed of two magnets 6a and 7a. 7 shows an example in which the inner peripheral surface of the magnet 7 is cut (shape with the inner surface recessed), but conversely, the outer peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are shaved (the outer surface is recessed). May also be provided.
In the second embodiment, the thickness of both the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is changed. However, as shown in FIG. 6, only one of the magnetic flux applying magnet 6 or the magnetic flux attracting magnet 7 is used. The thickness may be changed.
In addition, in FIG. 6, although the example which changes only the thickness of the magnetic flux provision magnet 6 was shown as an example, you may change the thickness of only the magnetic flux attraction magnet 7. FIG.

  Embodiment 3 will be described with reference to FIGS. 7A is a view of the rotation angle detection device viewed from the Z-axis direction, and FIG. 7B is a cross-sectional view of the rotation angle detection device along the Z-axis direction. In the said 1st, Example 2, the magnetic flux provision magnet 6 and the magnetic flux attraction magnet 7 showed the example which exhibits circular arc shape seeing from a Z-axis direction. On the other hand, in the third embodiment, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are arranged in parallel when viewed from the Z-axis direction.

  As described in (3) of the background art section, when each of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is configured by a flat plate magnet and arranged in parallel when viewed from the Z-axis direction, the magnetic flux applying magnet 6 and Since the leakage flux is large at both ends of the magnetic flux attracting magnet 7 in the X-axis direction, when the installation position of the Hall element 2 is shifted in the X-axis direction, as shown in the solid line B ′ in FIG. The density of magnetic flux passing through the Hall element 2 is reduced. As a result, a predetermined output cannot be obtained from the Hall element 2, which causes a rotation angle detection error.

  Therefore, in this third embodiment, in order to solve the above problems, when the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are viewed from the Z-axis direction as shown in FIG. Is so thin that the end B2 side is thick. That is, the distance between the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 and the Hall element 2 is configured to gradually decrease toward the end B2. The change in the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is set based on the change width of the magnetic flux density passing through the Hall element 2 that changes according to the installation position of the Hall element 2 being shifted in the X-axis direction. The That is, the magnetic flux density passing through the Hall element 2 is set so as not to change even if the installation position of the Hall element 2 is shifted in the X-axis direction.

The rotation angle detection device of the present embodiment is provided as described above, so that the installation position of the Hall element 2 is X from the center of the magnetic flux applying magnet 6 and the magnetic flux attraction magnet 7 due to an assembly error of the rotation angle detection device. Even if it deviates in the axial direction, the magnetic flux application magnet 6 and the magnetic flux attracting magnet 7 that are thick in the deviating direction can eliminate the decrease in the magnetic flux density that passes through the Hall element 2 due to the deviation. Specifically, as shown by a solid line B in FIG. 8, even if the installation position of the Hall element 2 is shifted from the center in the X-axis direction, the magnetic flux density does not decrease, and an almost ideal magnetic flux density can be obtained.
That is, because the magnetic flux density does not decrease even if the installation position of the Hall element 2 is shifted in the X-axis direction due to an assembly error of the rotation angle detection device, the occurrence of a rotation angle detection error can be prevented.

  In Example 3, as a means for thinning the center B1 of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7, the shape obtained by cutting the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 (the shape in which the inner surface is recessed). However, conversely, the same effect as in the third embodiment can be obtained even if the outer peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are formed in a shape (a shape in which the outer surface is recessed). Obtainable.

Moreover, in this Example 3, although the example which changes the thickness of both the magnetic flux provision magnet 6 and the magnetic flux attraction magnet 7 was shown, as shown in FIG. 9, only one of the magnetic flux provision magnet 6 and the magnetic flux attraction magnet 7 is shown. The thickness may be changed. That is, the center B1 of one of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 may be thin and the end B2 side thick, and the other thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 may be provided constant. Even if it provides in this way, the same effect as Example 3 can be acquired.
In FIG. 9, as an example, the thickness of only the magnetic flux applying magnet 6 is changed, but the thickness of only the magnetic flux attracting magnet 7 may be changed.

A fourth embodiment will be described with reference to FIGS. 10 and 11. 10A is a view of the rotation angle detection device as viewed from the Z-axis direction, and FIG. 10B is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
As described in (4) of the background art section, both ends A2 in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 have a characteristic of increasing the leakage magnetic flux.
Therefore, in the rotation angle detection device in which the Hall element 2 is installed at the center in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7, when the installation position of the Hall element 2 is shifted in the Z-axis direction, FIG. As indicated by the solid line C ′, the density of magnetic flux passing through the Hall element 2 decreases as the amount of deviation increases. As a result, a predetermined output cannot be obtained from the Hall element 2, which causes a rotation angle detection error.

Therefore, in this embodiment, in order to solve the above-described problems, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 along the Z-axis direction are thin around the set position of the Hall element 2. The side away from the set position is provided to be thick.
Specifically, as shown in FIG. 10B, when the installation position of the Hall element 2 is in the center in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as in this embodiment, The magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are provided such that the center A1 in the Z-axis direction is thin and the both ends A2 side in the Z-axis direction are thick. Changes in the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are set based on the change width of the magnetic flux density passing through the Hall element 2 that changes according to the installation position of the Hall element 2 being shifted in the Z-axis direction. . That is, the magnetic flux density passing through the Hall element 2 is set so as not to change even if the installation position of the Hall element 2 is shifted in the Z-axis direction.
In the fourth embodiment, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are changed by providing an inward recess α that draws an arc in the Z-axis direction on the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7. I have it.

  By providing the rotation angle detection device of the present embodiment as described above, even if the installation position of the Hall element 2 is shifted in the Z-axis direction due to an assembly error of the rotation angle detection device or the like, the rotation angle detection device is thicker in the shifted direction. The reduced magnetic flux application magnet 6 and the magnetic flux attracting magnet 7 can eliminate a decrease in magnetic flux density that passes through the Hall element 2 due to deviation. Specifically, as indicated by a solid line C in FIG. 11, the magnetic flux density does not decrease even when the installation position of the Hall element 2 is shifted from the center in the Z-axis direction, and an almost ideal magnetic flux density can be obtained.

That is, the following effects can be obtained by combining the technique of the fourth embodiment with the third embodiment.
The magnetic flux density does not decrease even if the installation position of the Hall element 2 is shifted in the Z-axis direction due to an assembly error of the rotation angle detection device, and the magnetic flux density is not changed even if the installation position of the Hall element 2 is shifted in the X-axis direction. It will not decline. For this reason, even if the installation position of the Hall element 2 is shifted in the Z-axis direction or the X-axis direction due to an assembly error of the rotation angle detection device, the magnetic flux density does not decrease. Can be prevented.

Example 5 will be described with reference to FIG. FIG. 12 is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
In Example 4 described above, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 in the Z-axis direction are changed by providing inward depressions α on the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7. On the other hand, this Example 5 provided the outward hollow (beta) in the outer peripheral surface of the magnetic flux provision magnet 6 and the magnetic flux attraction magnet 7, and made the thickness of the magnetic flux provision magnet 6 and the magnetic flux attraction magnet 7 change in the Z-axis direction. Is.
Even if it provides in this way, the same effect as Example 4 is acquired.

Example 6 will be described with reference to FIG. FIG. 13 is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
In the fourth embodiment, an example in which the inward depression α is provided on the inner peripheral surfaces of both the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 has been described. On the other hand, in the sixth embodiment, only one of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is provided with an inward depression α.
Even if it provides in this way, the same effect as Example 4 is acquired.
FIG. 13 shows an example in which the inward depression α is provided only in the magnetic flux application magnet 6 as an example, but the inward depression α may be provided only in the magnetic flux attracting magnet 7.

Example 7 will be described with reference to FIG. FIG. 14 is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
In the fifth embodiment, the example in which the outward depression β is provided on the outer peripheral surfaces of both the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 has been described. On the other hand, in the seventh embodiment, only one of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is provided with the outward recess β.
Even if it provides in this way, the same effect as Example 4 is acquired.
FIG. 14 shows an example in which the outward depression β is provided only in the magnetic flux application magnet 6 as an example, but the outward depression β may be provided only in the magnetic flux attracting magnet 7 as a matter of course.

Example 8 will be described with reference to FIG. FIG. 15 is a sectional view taken along the Z-axis direction of the rotation angle detection device.
In Example 4 described above, an example in which the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are changed over a relatively wide range in the Z-axis direction has been described. On the other hand, in the eighth embodiment, the thickness is changed so that only the center A1 in the Z-axis direction becomes thin. Specifically, in Example 8, the inward depression α is provided only at the center A1 in the Z-axis direction of the inner peripheral surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7.
In the rotation angle detection device with a relatively small assembly error, the amount of displacement of the Hall element 2 in the Z-axis direction is small. For this reason, as in the eighth embodiment, by providing only the center A1 in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7, the same effect as that of the fourth embodiment can be obtained.

  In the eighth embodiment, the inward depression α is provided at the center A1 of the inner peripheral surfaces of both the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7. However, as in the eighth embodiment, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are provided. An outward recess β may be provided at the center A1 of the outer peripheral surface of the outer peripheral surface, or an inward recess α may be provided at the center A1 of only one inner peripheral surface of the magnetic flux applying magnet 6 or the magnetic flux attracting magnet 7 as in the sixth embodiment. Further, as in the seventh embodiment, an outward recess β may be provided at the center A1 of only one outer peripheral surface of the magnetic flux applying magnet 6 or the magnetic flux attracting magnet 7.

Example 9 will be described with reference to FIG. FIG. 16A is a view of the rotation angle detection device as viewed from the Z-axis direction, and the broken line shown in FIG. 16A indicates the innermost surface of the most depressed magnet.
(Description of the magnet shape when the rotation angle detector is viewed from the Z-axis direction)
As described in (1) of the background art section, when the installation position of the Hall element 2 is shifted in the X-axis direction in a state where the rotation angle of the rotor 1 is 90 °, the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 As the distance to the Hall element 2 approaches, the magnetic flux density passing through the Hall element 2 increases {see the broken line A ′ in FIG. 16B}. For this reason, when the setting position of the Hall element 2 is shifted in the X-axis direction due to an error during assembly, the magnetic flux density passing through the Hall element 2 is increased, and an output of a predetermined level or more is generated from the Hall element 2. This will cause a detection error of the rotation angle.

  Therefore, in the first embodiment, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 viewed from the Z-axis direction are provided so that the center B1 is thick and the end B2 side is thin. Here, (A) The change in the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is a change width of the magnetic flux density passing through the Hall element 2 that changes in accordance with the installation position of the Hall element 2 being shifted in the X-axis direction. Is set based on Thereby, even if the installation position of the Hall element 2 is shifted in the X-axis direction, the magnetic flux density passing through the Hall element 2 is set so as not to change.

The above (A) will be specifically described. When the inner surface shape and outer surface shape of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the Z-axis direction are drawn with simple arcs (arcs drawn with a constant radius, elliptical arcs), variations in magnetization direction, magnets In some cases, the magnetic flux distribution applied to the X-axis may change due to variations in the density of the magnetic material forming the magnetic field or the case where the magnetic circuit is configured only by the magnet without using the yoke 4. When such a change occurs, if the installation position of the Hall element 2 is shifted in the X-axis direction, the magnetic flux density passing through the Hall element 2 changes slightly (see the broken line A "in FIG. 16B). .
When the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 viewed from the Z-axis direction is symmetrical with respect to the center B1, the magnetic flux distribution applied to the X-axis is the rotation center (in the present embodiment, the Hall element). It is possible to approximate it with a multi-order curve having the reference position (2) as a vertex. By utilizing this regularity, the magnet shape has at least one of the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 and has a multi-order curve (curvature) with the rotation center (reference setting position of the Hall element 2) as the apex. By adopting a magnet shape, the magnetic flux density passing through the Hall element 2 can be prevented from changing even if the installation position of the Hall element 2 is shifted in the X-axis direction within a predetermined range.

Specifically, in this embodiment, the outer surface shape of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the Z-axis direction is considered in consideration of the change in the magnetic flux distribution applied to the X axis due to variations in the magnetization direction. The curvature A and the curvature B of the inner surface shape are represented by the following equations, and the distribution of magnetic flux applied to the X axis within the range of the installation position of the Hall element 2 is made substantially constant {the solid line in FIG. 16 (b) See A}.
A = a ₁ X ⁿ + b ₁ X ⁿ⁻¹ ... C ₁
B = a ₂ X ⁿ + b ₂ X ⁿ⁻¹ ... C ₂
Note that the variable X in the equations c ₁ and c ₂ indicates the length of the magnet in the X-axis direction.
As described above, in this embodiment, the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are magnets having a multi-order curve (curvature), thereby forming variations in the magnetization direction and forming a magnet. The variation in the magnetic material density or the case where the magnetic circuit is constituted by only the magnet without using the yoke 4 can cancel the change in the magnetic flux distribution applied to the X axis, and the installation position of the Hall element 2 can be reduced. Even if it deviates in the X-axis direction within a predetermined range, the magnetic flux density passing through the Hall element 2 can be kept unchanged.

  In this embodiment, an example is shown in which the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 viewed from the Z-axis direction are magnets having a multi-order curve (curvature). Only one of the inner surface and the outer surface of the magnet 6 and the magnetic flux attracting magnet 7 may have a magnet shape having a multi-degree curve (curvature).

Example 10 will be described with reference to FIG. FIG. 17A is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
(Description of magnet shape along the Z-axis direction of the rotation angle detector)
As described in (4) of the background art section, both ends A2 in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 have a characteristic of increasing the leakage magnetic flux.
For this reason, in the rotation angle detection device in which the Hall element 2 is installed at the center in the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7, when the installation position of the Hall element 2 is shifted in the Z-axis direction, As the value increases, the magnetic flux density passing through the Hall element 2 decreases {see the broken line C ′ in FIG. 17B}. As a result, a predetermined output cannot be obtained from the Hall element 2, which causes a rotation angle detection error.

  Therefore, in Examples 4 to 8 described above, the thicknesses of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 along the Z-axis direction are thin around the setting position of the Hall element 2 and are separated from the setting position of the Hall element 2. It is provided so that the side is thick. Here, (B) the change in the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is a change width of the magnetic flux density passing through the Hall element 2 that changes according to the installation position of the Hall element 2 being shifted in the Z-axis direction. Is set based on Thereby, even if the installation position of the Hall element 2 is shifted in the Z-axis direction, the magnetic flux density passing through the Hall element 2 is set so as not to change.

The above (B) will be specifically described. When the inner surface shape and outer surface shape of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 viewed from the X-axis direction are drawn with simple arcs (arcs drawn with a constant radius, elliptical arcs), variations in magnetization direction, magnets In some cases, the magnetic flux distribution applied to the Z-axis may change due to variations in the density of the magnetic material forming the magnetic field or the case where the magnetic circuit is configured by only the magnet without using the yoke 4. When such a change occurs, if the installation position of the Hall element 2 is shifted in the Z-axis direction, the magnetic flux density passing through the Hall element 2 changes slightly (see the broken line C ″ in FIG. 17B). .
When the thickness of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the X-axis direction is symmetrical with respect to the center A1, the magnetic flux distribution applied to the Z-axis is the apex of the reference set position of the Hall element 2 Can be approximated by a multi-order curve. By utilizing this regularity, the magnet shape of at least one of the inner surface and outer surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is changed to a magnet shape having a multi-order curve (curvature) with the reference set position of the Hall element 2 as a vertex. Thus, even if the installation position of the Hall element 2 is shifted in the Z-axis direction within a predetermined range, the magnetic flux density passing through the Hall element 2 can be prevented from changing.

Specifically, in this embodiment, the outer surface shape of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the X axis direction is considered in consideration of the change in the magnetic flux distribution applied to the Z axis due to variations in the magnetization direction. The curvature C and the curvature D of the inner surface shape are represented by the following equations, and the distribution of magnetic flux applied to the Z axis within the range of the installation position of the Hall element 2 is made substantially constant {the solid line in FIG. 17 (b) See C}.
C = a ₃ Z ⁿ + b ₃ Z ^n-1 ... C _{3
^{D = a 4 Z n + b}} 4 Z n-1 ··· c 4
Note that the variable Z in the c ₃ and c ₄ equations indicates the length of the magnet in the Z-axis direction.
As described above, in this embodiment, the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are magnets having a multi-order curve (curvature), thereby forming variations in the magnetization direction and forming a magnet. The variation in magnetic flux density applied to the Z-axis can be offset by the variation in the density of the magnetic material or the case where the magnetic circuit is constituted by only the magnet without using the yoke 4. Even if it deviates in the Z-axis direction within a predetermined range, the magnetic flux density passing through the Hall element 2 can be prevented from changing.

  In this embodiment, an example is shown in which the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 along the Z-axis are magnets having a multi-order curve (curvature). 6. Only one of the inner surface and the outer surface of the magnetic flux attracting magnet 7 may have a magnet shape having a multi-degree curve (curvature).

Example 11 will be described with reference to FIG. FIG. 18 is a view of the rotation angle detection device as viewed from the Z-axis direction, and the broken line shown in the drawing indicates the inner surface of the most depressed magnet.
(Description of the magnet shape when the rotation angle detector is viewed from the Z-axis direction)
In the ninth embodiment, the outer surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the Z-axis direction is changed to a magnet shape having one multi-order curve (curvature). 7 shows an example in which the magnet shape of the inner surface 7 is also a magnet shape having one multi-order curve (curvature).
On the other hand, in this embodiment, as shown in FIG. 18, when the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are viewed from the Z-axis direction, the curvature E of the magnet shape on the left outer surface with respect to the center B1 Curve) and the curvature F (multi-order curve) of the magnet shape on the right outer surface, and the curvature G (multi-order curve) of the magnet shape on the left inner surface with respect to the center B1, and the magnet on the right inner surface The curvature H (multiple curve) of the shape is made different.
^{_{E = a 5 X n + b}} 5 X n-1 ··· c 5
F = a ₆ X ⁿ + b ₆ X ⁿ⁻¹ ... C ₆
G = a ₇ X ⁿ + b ₇ X ⁿ⁻¹ ... C _{7
^{H = a 8 X n + b}} 8 X n-1 ··· c 8
_{Incidentally, c 5, c 6, c} 7, c 8 Expression of the variable X shows the length in the X-axis direction of the magnet.
In this way, by varying the curvature of the magnet shape of the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as seen from the Z-axis direction, the variation in the magnetization direction and the density of the magnetic material forming the magnet can be reduced. The variation in the magnetic flux distribution applied to the X-axis can be canceled out by the variation or the case where the magnetic circuit is constituted by only the magnet without using the yoke 4, and the magnetic flux distribution applied to the X-axis can be accurately obtained. It can be made uniform.

  In this embodiment, an example is shown in which the left and right curvatures of both the inner surface and the outer surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as viewed from the Z-axis direction are changed. Only one of the inner surface and the outer surface may be made to have different curvatures.

Example 12 will be described with reference to FIG. FIG. 19 is a cross-sectional view of the rotation angle detection device along the Z-axis direction.
(Description of magnet shape along the Z-axis direction of the rotation angle detector)
In the tenth embodiment, the magnetic shapes of the outer surfaces along the Z-axis direction of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are changed to magnet shapes having one multi-order curve (curvature). The example in which the magnet shape of the inner surface of the magnet is also a magnet shape having one multi-order curve (curvature) is shown.
On the other hand, in this embodiment, as shown in FIG. 19, when the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 are viewed from the X-axis direction, the curvature I of the magnet shape on the left outer surface with respect to the center A1 Curve) and the curvature J (multi-order curve) of the magnet shape on the right outer surface, the curvature K (multi-order curve) of the magnet shape on the left inner surface with respect to the center A1, and the magnet on the right inner surface The shape curvature L (multiple curve) is made different.
^{_{I = a 9 Z n + b}} 9 Z n-1 ··· c 9
^{_{J = a 10 Z n + b}} 10 Z n-1 ··· c 10
^{_{K = a 11 Z n + b}} 11 Z n-1 ··· c 11
^{_{L = a 12 Z n + b}} 12 Z n-1 ··· c 12
Note that the variable Z in the expressions c ₉ , c ₁₀ , c ₁₁ , and c ₁₂ indicates the length of the magnet in the Z-axis direction.
In this way, by varying the curvature of the magnet shape of the inner and outer surfaces of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 as seen from the X-axis direction, the variation in the magnetization direction and the density of the magnetic material forming the magnet can be reduced. The variation in the magnetic flux distribution applied to the Z-axis can be canceled by variation or when the magnetic circuit is configured by only the magnet without using the yoke 4, and the magnetic flux distribution applied to the Z-axis can be obtained with high accuracy. It can be made uniform.

  In this embodiment, the left and right curvatures of both the inner surface and the outer surface of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 along the Z-axis direction are shown. Only one of the inner surface and the outer surface may have different left and right curvatures.

[Modification]
In the above embodiment, the fixing member is fixed and the rotor 1 is rotated. However, on the contrary, the member corresponding to the rotor 1 is fixed and the magnetic detection element (in the embodiment, the hall in which the Hall element 2 is incorporated) is fixed. A structure in which a member supporting IC3) is rotated may be employed. In other words, the rotation angle may be detected from the output of the magnetic detection element by rotating the magnetic detection element and fixing the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7.

In the above-described embodiment, an example in which one magnetic detection element (in the embodiment, the Hall IC 3 including the Hall element 2) is mounted is shown, but a plurality of magnetic detection elements may be arranged. Alternatively, only the Hall element 2 constituting the Hall IC 3 may be disposed inside the magnetic flux generating means 5 (the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7), and the signal processing circuit may be disposed outside the magnetic flux generating means 5. That is, for example, the signal processing circuit of the Hall element 2 may be provided in a control device separated from the rotation angle detection device.
In the above embodiment, an example of detecting the opening of the throttle valve is shown as a specific example of the rotation angle detection device. However, the rotation angle detection device is provided so as to detect other rotation angles such as the rotation angle of the arm portion of the industrial robot. May be.
In the above embodiment, the example in which the yoke 4 is provided around the outer sides of the magnetic flux applying magnet 6 and the magnetic flux attracting magnet 7 is shown, but a configuration in which the yoke 4 is omitted may be used.

It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (Example 1). It is a graph which shows the relationship between magnetic flux density and a rotation angle (Example 1). 7 is a graph showing a relationship between a deviation amount of a magnetic detection element in an X-axis direction and a magnetic flux density (Example 1). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (modified example of Example 1). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (Example 2). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction (the modification of Example 2). FIG. 6 is a view of the rotation angle detection device viewed from the Z-axis direction and a cross-sectional view along the Z-axis direction (Example 3). 12 is a graph showing the relationship between the amount of deviation in the X-axis direction of the magnetic detection element and the magnetic flux density (Example 3). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction (modified example of Example 3). FIG. 6 is a view of the rotation angle detection device viewed from the Z-axis direction and a cross-sectional view along the Z-axis direction (Example 4). 10 is a graph showing the relationship between the amount of deviation of the magnetic detection element in the Z-axis direction and the magnetic flux density (Example 4). (Example 5) which is sectional drawing in alignment with the Z-axis direction of a rotation angle detection apparatus. (Example 6) which is sectional drawing which follows the Z-axis direction of a rotation angle detection apparatus. (Example 7) which is sectional drawing in alignment with the Z-axis direction of a rotation angle detection apparatus. (Example 8) which is sectional drawing in alignment with the Z-axis direction of a rotation angle detection apparatus. FIG. 10 is a diagram of a rotation angle detection device as viewed from the Z-axis direction and a graph showing the relationship between the amount of deviation of the magnetic detection element in the X-axis direction and the magnetic flux density (Example 9). FIG. 10 is a cross-sectional view along the Z-axis direction of the rotation angle detection device and a graph showing the relationship between the Z-axis direction deviation amount of the magnetic detection element and the magnetic flux density (Example 10). (Example 11) which was the figure which looked at the rotation angle detection apparatus from the Z-axis direction. (Example 12) which is sectional drawing which follows the Z-axis direction of a rotation angle detection apparatus. Yes (Example 12). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (conventional example). It is explanatory drawing of the rotation angle of a rotor (conventional example). It is a graph which shows the relationship between magnetic flux density and a rotation angle (conventional example). It is a graph which shows the relationship between the deviation | shift amount of a X direction of a magnetic detection element, and magnetic flux density (conventional example). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (conventional example). It is the figure which looked at the rotation angle detection apparatus from the Z-axis direction, and sectional drawing in alignment with a Z-axis direction (conventional example). It is a graph which shows the relationship between the deviation | shift amount of a X direction of a magnetic detection element, and magnetic flux density (conventional example). It is a graph which shows the relationship between the Z-axis direction deviation | shift amount of a magnetic detection element, and magnetic flux density (conventional example).

Explanation of symbols

1 Rotor 2 Hall element (Magnetic detection element)
3 Hall IC
4 yoke 5 magnetic flux generating means 6 magnetic flux applying magnet 7 magnetic flux attracting magnet A1 center A2 in the Z-axis direction of the magnetic flux applying magnet and the magnetic flux attracting magnet B1 end of the Z-axis direction of the magnetic flux applying magnet and the magnetic flux attracting magnet B1 magnetic flux viewed from the Z-axis direction The center of the magnetic flux applying magnet and the magnetic flux attracting magnet B2 End of the magnetic flux applying magnet and the magnetic flux attracting magnet as viewed from the Z-axis direction

Claims (19)

A magnetic sensing element disposed on the rotation axis;
A magnetic flux application magnet that is disposed opposite to both sides of the magnetic detection element at a distance and applies a magnetic flux toward the magnetic detection element, and a magnetic flux that attracts the magnetic flux applied from the magnetic flux application magnet toward the magnetic detection element A magnetic flux generation means comprising an attraction magnet,
In the rotation angle detection device that detects a change in relative rotation angle between the magnetic detection element and the magnetic flux generation means by a magnetic flux density passing through the magnetic detection element,
When the magnetic flux applying magnet and the magnetic flux attracting magnet exhibit an arc shape along the rotation direction when viewed from the rotation axis direction,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided with a thickness as viewed from the direction of the rotation axis that is thick at the center and thin at the end side. A magnetic sensing element disposed on the rotation axis;
A magnetic flux application magnet that is disposed opposite to both sides of the magnetic detection element at a distance and applies a magnetic flux toward the magnetic detection element, and a magnetic flux that attracts the magnetic flux applied from the magnetic flux application magnet toward the magnetic detection element A magnetic flux generation means comprising an attraction magnet,
In the rotation angle detection device that detects a change in relative rotation angle between the magnetic detection element and the magnetic flux generation means by a magnetic flux density passing through the magnetic detection element,
When the magnetic flux applying magnet and the magnetic flux attracting magnet are arranged in parallel when viewed from the rotational axis direction, at least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has a thin thickness when viewed from the rotational axis direction, and the center is thin. The rotation angle detecting device is characterized in that the end side is thickly provided. A magnetic sensing element disposed on the rotation axis;
A magnetic flux application magnet that is disposed opposite to both sides of the magnetic detection element at a distance and applies a magnetic flux toward the magnetic detection element, and a magnetic flux that attracts the magnetic flux applied from the magnetic flux application magnet toward the magnetic detection element A magnetic flux generation means comprising an attraction magnet,
In the rotation angle detection device that detects a change in relative rotation angle between the magnetic detection element and the magnetic flux generation means by a magnetic flux density passing through the magnetic detection element,
When the magnetic flux applying magnet and the magnetic flux attracting magnet are arranged parallel to the rotation axis and arranged parallel to the rotation axis direction,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has a thickness along the rotation axis direction, the periphery of the setting position of the magnetic detection element is thin, and the side away from the setting position of the magnetic detection element is provided thick,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided with a thickness as viewed from the direction of the rotation axis that is thin at the center and thick at the end side. The rotation angle detection device according to claim 1,
The magnetic flux applying magnet and the magnetic flux attracting magnet are each constituted by a single magnet having a semi-cylindrical shape, and have a substantially cylindrical shape divided in the diameter direction by the magnetic flux applying magnet and the magnetic flux attracting magnet. Rotation angle detection device. The rotation angle detection device according to claim 1,
The magnetic flux applying magnet and the magnetic flux attracting magnet are each configured by arranging a plurality of magnets arranged in an arc shape in the rotational direction when viewed from the rotational axis direction. In the rotation angle detection device according to claim 2 or 3,
The magnetic flux applying magnet and the magnetic flux attracting magnet are each constituted by one magnet, arranged in parallel with the rotation axis, and arranged in parallel when viewed from the direction of the rotation axis. In the rotation angle detection device according to claim 3,
When the magnetic detection element is installed in the center of the rotation axis direction of the magnetic flux generation means,
The rotation angle detection device according to claim 1, wherein the thickness along the rotation axis direction of at least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided such that the center in the rotation axis direction is thin and both ends in the rotation axis direction are thick. In the rotation angle detection device according to claim 7,
The rotation angle detection device characterized in that the change in thickness along the rotation axis direction of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided only in a central portion in the rotation axis direction. In the rotation angle detection device according to any one of claims 1 to 8,
The change in thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided based on the change width of the magnetic flux density passing through the magnetic detection element that changes in accordance with the installation position of the magnetic detection element. A rotation angle detection device. In the rotation angle detection device according to any one of claims 1 to 9,
The rotation angle detecting device is characterized in that the change in thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided by recessing the inner surface on the side where the magnetic detection element is arranged. In the rotation angle detection device according to any one of claims 1 to 9,
The rotation angle detecting device according to claim 1, wherein the thickness of the magnetic flux applying magnet and the magnetic flux attracting magnet is provided by recessing an outer surface on a side different from a side where the magnetic detecting element is arranged. In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has an inner surface on the side where the magnetic detection element is disposed as viewed from the direction of the rotation axis, provided on a curved surface having a multi-order curve. apparatus. In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has an outer surface on a side different from a side on which the magnetic detection element is disposed when viewed from the rotation axis direction, provided on a curved surface having a multi-order curve. A rotation angle detection device. In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is:
The inner surface on the side where the magnetic detection element is arranged as viewed from the direction of the rotation axis is provided on a curved surface having a multi-order curve,
A rotation angle detection device, wherein an outer surface on a side different from a side on which the magnetic detection element is arranged when viewed from the rotation axis direction is provided on a curved surface having a multi-order curve. In the rotation angle detection device according to any one of claims 12 to 14,
A rotation angle detection device characterized in that at least one of the multi-order curves of the inner surface and the outer surface viewed from the rotation axis direction is provided asymmetrically in the left and right curvatures as viewed from the rotation axis direction. In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has an inner surface on the side where the magnetic detection element is disposed along the rotation axis direction provided on a curved surface having a multi-order curve. . In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet has an outer surface on a side different from a side on which the magnetic detection element is disposed along a rotation axis direction provided on a curved surface having a multi-order curve. Rotation angle detection device. In the rotation angle detection device according to any one of claims 1 to 11,
At least one of the magnetic flux applying magnet and the magnetic flux attracting magnet is:
The inner surface on the side where the magnetic detection element along the rotation axis direction is disposed is provided on a curved surface having a multi-order curve,
A rotation angle detection device, wherein an outer surface on a side different from a side on which the magnetic detection element is disposed along a rotation axis direction is provided on a curved surface having a multi-order curve. In the rotation angle detection device according to any one of claims 16 to 18,
At least one of the inner and outer curved lines along the rotation axis direction has different curvature changes on the left and right of the set position of the magnetic sensing element as viewed from the direction orthogonal to the rotation axis, and is viewed from the direction orthogonal to the rotation axis. A rotation angle detection device, wherein the rotation angle detection device is provided asymmetrically with respect to a set position of the magnetic detection element.

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