JP2003057069A - Apparatus for detecting angle of rotation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it has been impossible to detect the accurate angle of rotation since the output characteristics of a Hall IC 6 varies when an external magnetism is provided from outside an apparatus for detecting the angle of rotation and the external magnetism crosses a core 2 and the Hall IC 6. SOLUTION: By providing an external magnetism guiding magnetic path with a magnetic resistance lower than a magnetic resistance which passes the core 2 and the Hall IC 6 in the vicinity of the Hall IC 6, the external magnetism provided from the outside is prevented from passing the Hall IC 6. In addition, a magnet 4 arranged in a magnet arranging gap 3 is provided in a magnet shape in which magnetic short circuits do not occur. By this, in the case that the external magnetism is provided from outside the apparatus for detecting the angle of rotation, the external magnetism is guided to the outside by the external magnetism guiding magnetic path from one side of an external magnetism inductor 9 through the core 2 as shown in a broken line 10 to prevent the problem of the crossing of the external magnetism via the Hall IC 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device for detecting a relative rotation angle between a rotating member and a non-rotating member, and prevents the output characteristic of a magnetic detecting element from varying due to external magnetism. Regarding technology.

[0002]

2. Description of the Related Art A schematic structure of a rotation angle detecting device will be described with reference to FIG. The rotation angle detecting device has a substantially cylindrical shape divided in the diametrical direction, and has a yoke J3 made of a magnetic material in which magnets J2 having magnetic poles facing in the same direction are arranged in a magnet arrangement gap J1 of the divided portion. It is arranged inside and has a substantially cylindrical shape divided in the diametrical direction, and a Hall IC J5 (I including a magnetic detection element is incorporated in the magnetic detection gap J4 of the divided portion).
C) is provided with a magnetic core J6, and the rotation angle between the rotating member and the non-rotating member is based on the output signal of the Hall IC J5 which changes depending on the relative rotation position of the yoke J3 and the core J6. Is to detect.

[0003]

When external magnetism (magnetism given from the outside of the rotation angle detecting device) is applied from a direction inclined with respect to the rotation axis of the rotation angle detecting device, as shown by a broken line J7 in FIG. In addition, the external magnetism crosses the core J6, and the output characteristics of the Hall IC J5 fluctuate, making it impossible to accurately detect the rotation angle.

On the other hand, as shown in FIG. 6, when the magnet arrangement gap is M ₁ , the shortest gap between the yoke and the core is M ₂ , and the magnetic detection gap is M ₃ , M ₁ ² > 2M ₂ ² + M ₃ ² It is provided so as to satisfy the expression. In the rotation angle detecting device thus provided, when external magnetism is applied from the direction orthogonal to the rotation axis, the external magnetism crosses the core J6 and the Hall IC is moved as shown by the broken line J8 in FIG.
The output characteristics of J5 change. In this case also, it becomes impossible to accurately detect the rotation angle due to fluctuations in the output characteristics of the Hall IC J5. Therefore, as shown in FIG. 7, when the magnet arrangement gap M ₁ is made small and the external magnetism is attempted to escape to the outside through the yoke J 3, as shown by the broken line J 9, the short-circuit distance between both poles of the magnet J 2 becomes short, Figure 7
A short circuit of the magnetic flux shown by the solid line J10 occurs. As a result, the magnetic force applied to the yoke J3 is reduced and the detection accuracy is reduced, or the magnet J2 needs to be upsized to compensate for the reduction in magnetic force due to the short circuit of the magnetic flux.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent the output characteristics of a magnetic detection element from varying due to the influence of external magnetism and to detect an accurate rotation angle. To provide a simple rotation angle detection device.

[0006]

[Means for Solving the Problems] [Means for Claim 1] The rotation angle detecting device adopting the means for claim 1 is an external magnetic induction magnet having a magnetic resistance lower than the magnetic resistance passing through the core and the magnetic detecting element. A magnetic path is provided in the vicinity of the magnetic detection element so that external magnetism given from the outside does not pass through the magnetic detection element by passing through the external magnetic induction magnetic path, and the magnets arranged in each of the magnet arrangement gaps are magnetically short-circuited. Not provided in the shape of a magnet. With this arrangement, even if external magnetism is applied from the outside of the rotation angle detection device, the external magnetism does not cross the core through the magnetic detection element, and the output characteristic of the magnetic detection element is There is no problem that fluctuates depending on. Therefore, the influence of the external magnetism is suppressed as compared with the conventional case, and the accurate rotation angle can be detected.

[Means for Claim 2] A rotation angle detecting device adopting the means for claim 2 arranges a spacer made of a non-magnetic material on the outer side in the central axis direction of the core. An external magnetic inductor made of a magnetic material is arranged on the outside so that external magnetism given from the outside is guided to the outside through the core from the external magnetic inductor, and the magnets arranged in each magnet arrangement gap do not cause magnetic short circuit. It is provided in. By providing in this way, even if external magnetism is applied from the direction inclined with respect to the rotation axis of the rotation angle detection device, the external magnetism does not cross the core via the magnetic detection element, and magnetic detection is performed. There is no problem that the output characteristics of the element change due to external magnetism.
Therefore, the influence of external magnetism is suppressed as compared with the conventional one,
It is possible to accurately detect the rotation angle.

[Means of claim 3] When the means of claim 3 is adopted and the axial dimension of the spacer is L ₁ , the shortest gap between the yoke and the core is L ₂ , and the magnetic detection gap is L ₃ , 2L ₁ It may be provided so as to satisfy the expression represented by ² > 2L ₂ ² + L ₃ ² . By providing in this way, the effect shown by the means of claim 1 or claim 2 can be obtained.

[Means of claim 4] When the means of claim 4 is adopted and the axial dimension of the spacer is L ₁ , the shortest gap between the yoke and the core is L ₂ , and the magnetic detection gap is L ₃ , 2L ₁ You may provide so that the expression represented by> 2L < ₂ > + L < ₃ > may be satisfy | filled. By providing in this way, the effect shown by the means of claim 1 or claim 2 can be obtained.

According to a fifth aspect of the present invention, a rotation angle detecting device adopting the fifth aspect provides a shortest distance between divided yokes facing each other via a magnet so that an external magnetism given from the outside can be generated. Provided so as to lead from one of the divided yokes to the other of the divided yokes through a magnet,
By providing the magnet in a shape such that the magnetizing direction of the magnet is inclined with respect to the facing direction of the magnetic arrangement gap, the short-circuiting distance is extended and the short-circuiting of both poles of the magnet is suppressed. As a result, even if external magnetism is applied in a direction orthogonal to the rotation axis of the rotation angle detection device, the external magnetism does not cross the core through the magnetic detection element, and the output characteristics of the magnetic detection element are external. There is no problem of fluctuation due to magnetism. Therefore, the influence of the external magnetism is suppressed as compared with the conventional case, and the accurate rotation angle can be detected. Also,
Since the short-circuit distance between both poles of the magnet is long due to the inclined shape of the magnet, the short-circuit amount of the magnetic flux generated at both poles of the magnet is significantly reduced, and the reduction of the magnetic force generated at the yoke can be prevented. As a result, it is possible to solve the problem that the detection accuracy of the rotation angle detection device decreases, and it is not necessary to increase the size of the magnet to compensate for the decrease in magnetic force due to the short circuit of the magnetic flux.

[Means of claim 6] The means of claim 6 is adopted, the magnet arrangement gap is M ₁ , the short circuit distance is M ₁ ′, the shortest gap between the yoke and the core is M ₂ , and the magnetic detection gap is M _3.
In such a case, it may be provided so as to satisfy the formula represented by M ₁ ² <2M ₂ ² + M ₃ ² and the formula represented by M ₁ ' ² > 2M ₂ ² + M ₃ ² . By providing in this way, the effect shown by the means of claim 5 can be obtained.

[Means of Claim 7] The means of claim 7 is adopted, and the magnet arrangement gap is M ₁ , the short-circuit distance is M ₁ ′, the shortest gap between the yoke and the core is M ₂ , and the magnetic detection gap is M _3.
In this case, it may be provided so as to satisfy the formula represented by M ₁ <2M ₂ + M ₃ and the formula represented by M ₁ ′> 2M ₂ + M ₃ . By providing in this way, the effect shown by the means of claim 5 can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to two examples and modifications. [First Embodiment] A first embodiment will be described with reference to FIGS. 1 is a cross-sectional view of the rotation angle detection device viewed from the rotation axis direction and a cross-sectional view along the axial direction, and FIG. The rotation angle detection device shown in this embodiment is, for example, for detecting the opening of a throttle valve (corresponding to a rotating member), and is a ring-shaped yoke 1 that rotates integrally with a throttle valve and a member (not shown). And a core 2 disposed inside the yoke 1 and provided on a fixed member (corresponding to a non-rotating member).

The yoke 1 is arranged concentrically around the core 2, and a gap is provided between the yoke 1 and the core 2 so as not to come into contact with each other. The yoke 1 is a substantially cylindrical body made of a magnetic material (for example, iron) having a substantially cylindrical cross section divided in the diametrical direction, and each of the magnet arrangement gaps 3 formed in the two opposed divided portions. A magnet 4 magnetized in the same direction is arranged in the. By adopting such a configuration, one of the divided yokes 1 has an N pole polarity, and the other of the divided yokes 1 has an S pole polarity.

It should be noted that the yoke 1 is provided in a substantially elliptical shape as shown in FIG. 1, and in the central portion of the divided yoke 1 (the yoke 1 at the intermediate portion of the two magnets 4), the yoke 2 is located closest to the core 2. It is provided so as to approach.

The core 2 is concentrically arranged at the center of the yoke 1 and is made of a magnetic material (for example, iron) having a substantially cylindrical or polygonal shape divided in the diameter direction. Two Hall ICs 6 are arranged in the magnetic detection gap 5 formed in the divided portion. This Hall IC6
Is an IC in which a Hall element (magnetic detection element) and a signal amplification circuit are integrated, and outputs a voltage signal corresponding to the magnetic flux density passing through the magnetic detection gap 5 (magnetic flux density passing through the Hall IC 6).

The magnetic detection gap 5 in the core 2
Large gaps 7 are formed on both sides of the arc so as to be recessed in an arc shape. By forming the large gap portion 7, the magnetic flux flowing through the core 2 is concentrated on the Hall IC 6. Further, by forming the large gap portion 7 in an arc shape, more magnetic flux given from the yoke 1 can be made to flow in the core 2.

The operation of the rotation angle detecting device having the above structure will be described. The rotation angle detecting device is arranged such that at a position where the magnet arrangement gap 3 and the magnetic detection gap 5 coincide with each other on a straight line (the position shown in FIG. 1, hereinafter, the rotation angle at this position is 0 °).
N pole of magnet 4 → One side of yoke 1 → One side of core 2 → Magnetic detection gap 5 → Other side of core 2 → Other side of yoke 1 → Magnet 4
A magnetic circuit in which a magnetic flux flows through the path of the S pole (hereinafter, the flow direction of the magnetic flux is a positive direction) is formed. Then, when the yoke 1 rotates together with the throttle valve, a part of the magnetic flux flows from the other side of the core 2 to the one side (opposite direction),
This cancels out the magnetic flux flowing in the positive direction in the magnetic detection gap 5. Therefore, in the magnetic detection gap 5, a magnetic flux amount (Φ ₁ −Φ ₂ ) corresponding to the difference between the magnetic flux amount Φ ₁ flowing in the positive direction and the magnetic flux amount Φ ₂ flowing in the opposite direction flows.

When the rotation angle of the yoke 1 is in the range of 0 to 180 °, the magnetic flux amount Φ _{1 in the} positive direction decreases and the magnetic flux amount Φ ₂ in the opposite direction increases according to the rotation angle. Therefore, the rotation angle is 0
In the range of 180 °, the magnetic flux density passing through the magnetic detection gap 5 decreases depending on the rotation angle. At this time, the rotation angle is 9
At the position of 0 °, the amount of magnetic flux Φ ₁ in the positive direction becomes equal to the amount of magnetic flux Φ _{2 in the} opposite direction, and the two cancel each other out, resulting in a magnetic flux density of 0.
become. When the rotation angle of the yoke 1 is in the range of 180 to 360 °, the magnetic flux amount Φ _{1 in the} positive direction increases and the magnetic flux amount Φ ₂ in the opposite direction decreases according to the rotation angle. Therefore, the rotation angle is 18
In the range of 0 to 360 °, the magnetic flux density passing through the magnetic detection gap 5 increases according to the rotation angle. At this time, at the position where the rotation angle is 270 °, the amount of magnetic flux Φ ₁ in the positive direction and the amount of magnetic flux Φ _{2 in the} opposite direction become the same, and the two cancel each other out and the magnetic flux density becomes zero.

As described above, the rotation angle of the yoke 1 is 0 to
By rotating in the range of 360 °, the magnetic flux density passing through the magnetic detection gap 5 changes, and the output of the Hall IC 6 changes according to the change of the magnetic flux density. Hall IC6
Is read by a control device (not shown), and the control device detects the rotation angle of the yoke 1 (that is, the rotation angle of the throttle valve) from the output of the Hall IC 6. This time,
The control device detects the rotation angle while comparing the outputs of the two Hall ICs 6 and checking whether there is any abnormality.

In the rotation angle detecting device of this embodiment, an external magnetic induction magnetic path (a magnetic path through which the external magnetism shown by a broken line 10 in the figure passes) having a magnetic resistance lower than the magnetic resistance passing through the core 2 and the Hall IC 6 is It is provided in the vicinity of the Hall IC 6 to prevent external magnetism given from the outside from passing through the Hall IC 6. Further, the magnets 4 arranged in the magnet arrangement gap 3 are
It is provided in the shape of a magnet that does not cause a magnetic short circuit.

Next, a specific example of providing an external magnetic induction magnetic path having a magnetic resistance lower than the magnetic resistance passing through the core 2 and the Hall IC 6 in the vicinity of the Hall IC 6 will be described. Figure 1
As shown in (b), on both sides of the core 2 in the rotation axis direction,
A spacer 8 made of a non-magnetic material (for example, made of resin) having substantially the same axial length and the same outer diameter as the outer diameter of the core 2 is arranged. The spacer 8 has a substantially columnar shape. Further, an external magnetic dielectric 9 made of a magnetic material (for example, iron) is arranged at the outer end of each spacer 8 in the axial direction. A cross section of this external magnetic dielectric 9 is shown in FIG.

Here, the axial dimension of the spacer 8 is L ₁ ,
When the shortest gap between the yoke 1 and the core 2 is L ₂ and the magnetic detection gap 5 is L ₃ , it is provided so as to satisfy the expression represented by 2L ₁ ² > 2L ₂ ² + L ₃ ² .

The rotation angle detecting device shown in the first embodiment is
By adopting the above configuration, when external magnetism is applied from a direction inclined with respect to the rotation axis, the external magnetism is one of the external magnetic conductors 9 as shown by a broken line 10 in FIG. Through the core 2 to the other of the external magnetic conductors 9. As a result, even if external magnetism is applied from a direction inclined with respect to the rotation axis of the rotation angle detection device, the problem that the external magnetism crosses through the Hall IC 6 does not occur,
There is no problem that the output characteristics of the Hall IC 6 change due to external magnetism. Therefore, the influence of external magnetism is suppressed as compared with the conventional case, and the rotation angle detection device can accurately detect the rotation angle.

[Second Embodiment] A second embodiment will be described with reference to FIG. FIG. 3 is a sectional view of the rotation angle detection device as seen from the rotation axis direction. In addition, the substantially same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the shortest distance between the divided yokes 1 facing each other via the magnet 4 is shortened so that the external magnetism applied from the outside causes one of the divided yokes 1 → the magnet 4 → the division. The magnet 4 is provided so as to be guided to the other side of the magnet 1, and the magnet 4 is provided in such a shape that the magnetizing direction of the magnet 4 is inclined with respect to the facing direction of the magnetic arrangement gap 3. In order to suppress a short circuit, the magnet 4 is provided with its side surfaces (inner surface and outer surface) inclined.

Here, the magnet arrangement gap 3 is M ₁ , the short-circuit distance is M ₁ ′, the shortest gap between the yoke 1 and the core 2 is M ₂ ,
When the magnetic detection gap 5 is M ₃ , the formula represented by M ₁ ² <2M ₂ ² + M ₃ ² is satisfied, and the formula represented by M ₁ ' ² > 2M ₂ ² + M ₃ ² is also satisfied. Is provided.

The rotation angle detecting device shown in the second embodiment is
When the above configuration is adopted and the shortest distance of the divided yoke 1 (magnet arrangement gap 3 = M ₁ ) is provided, when the external magnetism is applied from the direction orthogonal to the rotation axis, the external magnetism Is, as indicated by the broken line 11 in FIG.
One of the divided yokes 1 is guided to the other of the divided yokes 1 through the magnet 4. As a result, even if external magnetism is applied in a direction orthogonal to the rotation axis of the rotation angle detection device, the external magnetism does not cross the Hall IC 6 and the output characteristic of the Hall IC 6 changes due to the external magnetism. There is no defect. Therefore, the influence of external magnetism is suppressed as compared with the conventional case, and the rotation angle detection device can accurately detect the rotation angle.

Further, since the short-circuiting distance M ₁ ′ between both poles of the magnet 4 is long due to the inclined shape of the magnet 4, the short-circuit amount of the magnetic flux generated at both poles of the magnet 4 is greatly reduced and generated in the yoke 1. It is possible to prevent a decrease in magnetic force. As a result, it is possible to solve the problem that the detection accuracy of the rotation angle detection device decreases, and it is not necessary to upsize the magnet 4 to compensate for the decrease in the magnetic flux due to the short circuit of the magnetic flux.

[Modification] In the above first embodiment, when the axial dimension of the spacer 8 is L ₁ , the shortest gap between the yoke 1 and the core 2 is L ₂ , and the magnetic detection gap 5 is L ₃ , 2L ₁ ^Although an example is shown in which the formula represented by ² > 2L ₂ ² + L ₃ ² is satisfied, it may be provided so as to satisfy the formula represented by 2L ₁ > 2L ₂ + L ₃ .

In the above second embodiment, when the magnet arrangement gap 3 is M ₁ , the short-circuit distance is M ₁ ′, the shortest gap between the yoke 1 and the core 2 is M ₂ , and the magnetic detection gap 5 is M ₃ , ₁ ² <together with satisfying the formula represented by ^{_{2M 2 2 + M 3 2,}} M 1 '2> has been shown an example in which so as to satisfy the formula expressed by ^{_{2M 2 2 + M 3 2,}} M 1 It may be provided so as to satisfy the expression represented by <2M ₂ + M ₃ and also satisfy the expression represented by M ₁ ′> 2M ₂ + M ₃ .

In the above embodiment, the core 2 is fixed and the yoke 1 is rotated, but the yoke 1 may be fixed and the core 2 may be rotated. In the above embodiment, an example in which two Hall ICs 6 are mounted has been shown, but one or more Hall ICs may be mounted. Also, a magnetic detection element (for example, a Hall element)
Only the magnetic detection gap 5 may be arranged and the signal amplification circuit may be arranged outside the core 2. That is, for example, the signal amplification circuit may be provided in the control 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, but it is provided so as to detect other rotation angles such as the rotation angle of the arm part of the industrial robot. May be.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rotation angle detection device as seen from the rotation axis direction and a cross-sectional view along the axial direction (first embodiment).

FIG. 2 is a cross-sectional view of an external magnetic conductor as seen from the direction of the rotation axis (first embodiment).

FIG. 3 is a cross-sectional view of the rotation angle detection device as seen from the rotation axis direction (second embodiment).

FIG. 4 is a cross-sectional view of the rotation angle detection device as seen from the rotation axis direction (conventional example).

FIG. 5 is a sectional view taken along the axial direction of the rotation angle detection device (conventional example).

FIG. 6 is a cross-sectional view of the rotation angle detection device as seen from the rotation axis direction (conventional example).

FIG. 7 is a cross-sectional view of the rotation angle detection device as seen from the rotation axis direction (conventional example).

[Explanation of symbols]

1 yoke 2 core 3 magnet arrangement gap 4 magnet 5 magnetic detection gap 6 Hall IC (IC with Hall element corresponding to magnetic detection element) 8 spacer 9 external magnetic induction L ₁ spacer axial dimension L ₂ yoke and core Shortest gap L ₃ Magnetic detection gap M ₁ Magnet arrangement gap (shortest distance of divided yoke 1) M ₁ 'short circuit distance M ₂ Shortest gap between yoke and core M ₃ Magnetic detection gap

Claims (7)

[Claims] 1. A magnetic pole, which is provided on one of a rotating member and a non-rotating member, has a substantially cylindrical shape divided in a diametrical direction, and is oriented in the same direction in each of magnet arrangement gaps formed in two opposing divided portions. And a yoke made of a magnetic material in which the magnet is arranged, and is arranged inside the yoke and is provided on the other of the rotating member or the non-rotating member that changes the angle relative to the yoke, And a core made of a magnetic material in which a magnetic detection element is arranged in a magnetic detection gap formed in the divided portion, and the shape is changed depending on a relative rotational position of the yoke and the core. In a rotation angle detection device that detects a rotation angle between the rotating member and the non-rotating member based on an output signal of the magnetic detection element, a magnetic field that passes through the core and the magnetic detection element. By providing an external magnetic induction magnetic path having a magnetic resistance lower than resistance in the vicinity of the magnetic detection element, external magnetism given from the outside does not pass through the magnetic detection element by passing through the external magnetic induction magnetic path. Thus, the rotation angle detection device is characterized in that the magnets arranged in each of the magnet arrangement gaps are provided in a magnet shape that does not cause a magnetic short circuit. 2. A magnetic pole, which is provided on one of a rotating member and a non-rotating member, has a substantially cylindrical shape divided in a diametrical direction, and is oriented in the same direction in each of magnet arrangement gaps formed in two opposing divided portions. And a yoke made of a magnetic material in which the magnet is arranged, and is arranged inside the yoke and is provided on the other of the rotating member or the non-rotating member that changes the angle relative to the yoke, And a core made of a magnetic material in which a magnetic detection element is arranged in a magnetic detection gap formed in the divided portion, and the shape is changed depending on a relative rotational position of the yoke and the core. In a rotation angle detecting device for detecting a rotation angle between the rotating member and the non-rotating member based on an output signal of the magnetic detection element, a non-magnetic material is provided outside the core in the central axis direction. While arranging the spacer of, the external magnetic derivative made of a magnetic material is arranged on the outer side in the central axis direction of the spacer, and the external magnetism given from the outside is guided from the external magnetic derivative to the outside through the core, The rotation angle detecting device, wherein the magnets arranged in each of the magnet arrangement gaps are provided in a magnet shape that does not cause a magnetic short circuit. 3. The rotation angle detecting device according to claim 1 or 2, wherein an axial dimension of the spacer is L ₁ , a shortest gap between the yoke and the core is L ₂ , and a magnetic detection gap is L ₃ . In this case, the rotation angle detecting device is provided so as to satisfy the expression represented by 2L ₁ ² > 2L ₂ ² + L ₃ ² . 4. The rotation angle detection device according to claim 1, wherein the spacer has an axial dimension of L ₁ , a shortest gap between the yoke and the core is L ₂ , and the magnetic detection gap is L ₃ . In this case, the rotation angle detecting device is provided so as to satisfy the expression represented by 2L ₁ > 2L ₂ + L ₃ . 5. A magnetic pole, which is provided on one of a rotating member and a non-rotating member, has a substantially cylindrical shape divided in a diametrical direction, and is oriented in the same direction in each of magnet arrangement gaps formed in two opposing divided portions. And a yoke made of a magnetic material in which the magnet is arranged, and is arranged inside the yoke and is provided on the other of the rotating member or the non-rotating member that changes the angle relative to the yoke, And a core made of a magnetic material in which a magnetic detection element is arranged in a magnetic detection gap formed in the divided portion, and the shape is changed depending on a relative rotational position of the yoke and the core. In a rotation angle detection device that detects a rotation angle between the rotating member and the non-rotating member based on an output signal of the magnetic detection element, A shortest distance between the yokes is provided so that external magnetism given from the outside is guided from one of the divided yokes to the other of the divided yokes through the magnet, and the shape of the magnet is A rotation angle detecting device, characterized in that the magnetizing direction is provided in a shape inclined with respect to the facing direction of the magnetic arrangement gap to extend the short-circuiting distance and suppress the short-circuiting of both poles of the magnet. 6. The rotation angle detecting device according to claim 5, wherein the magnet arrangement gap is M ₁ , the short circuit distance is M ₁ ′, the shortest gap between the yoke and the core is M ₂ , and the magnetic detection gap is M _3. When it is set, it is provided that the formula represented by M ₁ ² <2M ₂ ² + M ₃ ² is satisfied and the formula represented by M ₁ ' ² > 2M ₂ ² + M ₃ ² is satisfied. Characteristic rotation angle detector. 7. The rotation angle detecting device according to claim 5, wherein the magnet arrangement gap is M ₁ , the short circuit distance is M ₁ ′, the shortest gap between the yoke and the core is M ₂ , and the magnetic detection gap is M _3. In this case, the rotation angle detection is provided so as to satisfy the formula represented by M ₁ <2M ₂ + M ₃ and the formula represented by M ₁ '> 2M ₂ + M _3. apparatus.