JP2002323345A - Rotation angle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation angle sensor enabling both efficiency heightening and cost reduction. SOLUTION: This rotation angle sensor is equipped with a magnetic circuit constitution part 11 for generating a magnetic field, and a magnetic flux density detection part 10 for relatively rotating in the magnetic field. The magnetic flux density detection part 10 is constituted of a first Hall element 4 and a second Hall element 5 crossing each other on the rotation center line O. The sensor has a constitution wherein the rotation angle of the magnetic flux density detection part 10 to the magnetic circuit constitution part 11 is detected based on outputs A, B of the first Hall element 4 and the second Hall element 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a rotation angle sensor.

[0002]

2. Description of the Related Art Conventionally, a resolver type rotation angle sensor using a coil has been generally used to detect a rotation angle with high accuracy.

[0003] However, this resolver type rotation angle sensor has high detection accuracy, but has a problem that the cost of the product is high.

[0004] Conventionally, there has been a rotation angle sensor that includes a Hall element that relatively rotates in a magnetic field and detects a rotation angle from a magnetic flux density detected by the Hall element.

[0005] However, the rotation angle sensor using the Hall element has a problem that it is difficult to improve the detection accuracy while reducing the cost of the product.

The present invention has been made in view of the above problems, and has as its object to provide a rotation angle sensor that achieves both high performance and low cost.

[0007]

According to a first aspect of the present invention, there is provided a magnetic circuit constituting section for generating a magnetic field, and a magnetic flux density detecting section which rotates relatively in the magnetic field, and the magnetic flux density detecting section is arranged on the rotation center line. It comprises a first Hall element and a second Hall element that intersect each other, and detects the rotation angle of the magnetic flux density detector with respect to the magnetic circuit component based on the output of the first and second Hall elements. Rotation angle sensor.

A second invention is characterized in that, in the first invention, the first and second Hall elements are orthogonal to each other.

According to a third aspect of the present invention, in the first or second aspect, a configuration is used in which the output of the first and second Hall elements, which has a larger output change with respect to the rotation angle, is used as a signal for detecting the rotation angle. .

According to a fourth aspect of the present invention, in any one of the first to third aspects, the rotation angle region is determined by using, of the outputs of the first and second Hall elements, one having a smaller voltage change with respect to the rotation angle. It is characterized by having a configuration.

A fifth invention is characterized in that, in any one of the first to fourth inventions, permanent magnets having mutually opposite poles are used as the magnetic circuit component.

[0012]

According to the first aspect of the present invention, first,
Since the outputs of the second Hall elements are sinusoidal waves having different phases from each other, high sensor output resolution can be obtained over a wide rotation angle range, and detection accuracy can be improved.

Further, by using a Hall element as the magnetic flux density detecting section, the cost of the product can be reduced.

According to the second aspect, since the outputs of the first and second Hall elements are sine waves having phases different from each other by 90 degrees, a high sensor output resolution can be obtained over the entire rotation angle range, and the detection accuracy can be improved. Can be enhanced.

According to the third aspect of the present invention, by detecting the rotation angle using the steepest one of the outputs of the first and second Hall elements, a high sensor output resolution can be obtained over a wide rotation angle range. And the detection accuracy can be increased.

According to the fourth aspect, the rotation angle area is determined by using one of the outputs of the first and second Hall elements having a gentle gradient, and the rotation angle is determined based on the other output having a steep gradient. Can be specified.

According to the fifth aspect, the use of inexpensive permanent magnets as the magnetic circuit components reduces the cost of the product.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, FIGS. 1 and 2 show an example of a rotation angle sensor to which the present invention can be applied. This rotation angle sensor includes a case 1 and a rotation shaft 2 that rotate relative to each other. First and second Hall elements 7 and 8 are fixed to the case 1 via a support 6, while a rotation unit 3 is attached to the rotation shaft 2. , Permanent magnets 4 and 5 are fixed.

The permanent magnets 4, 5 provided as the magnetic circuit component 11 have opposite poles on the rotor 3, and are arranged symmetrically with respect to the rotation center line A. first,
The second Hall elements 7 and 8 are also arranged symmetrically about the rotation center line O and are sandwiched between the permanent magnets 4 and 5.

The first and second Hall elements 7 and 8 provided as the magnetic flux density detecting unit 10 connect the electric wire 9 with a signal corresponding to a magnetic flux density that changes as the permanent magnets 4 and 5 relatively rotate. Output via

The gist of the present invention is that the first and second Hall elements 7 and 8 cross each other on the rotation center line O.
In the present embodiment, the first and second Hall elements 7 and 8 are arranged so as to be orthogonal to each other, and are fixed to the case 1 via the support 6.

FIG. 3 shows how the voltages output from the first and second Hall elements 7 and 8 change according to the rotation angle. The output A of the first and second Hall elements 7, 8
B is a sine wave whose phase is different by 90 degrees. As a signal for detecting the rotation angle, as shown by a thick line in FIG. 3, one of the outputs A and B of the first and second Hall elements 7 and 8 having a larger voltage change with respect to the rotation angle is used. That is, the outputs A and B of the first and second Hall elements 7 and 8 are taken out in such a manner that the areas having large gradients are alternately switched.

For example, while the second Hall element 8 makes one rotation, the same output is obtained at two points such as point C and point D by the output B. By monitoring the output A, the rotation angle is specified. Configuration. In other words, the first and second Hall elements 7, 8 used as signals for detecting the rotation angle by using the output A, B of the first and second Hall elements 7, 8 having a smaller voltage change with respect to the rotation angle. It is configured to determine in which rotation angle region the outputs A and B are located.

As described above, the first and second Hall elements 7,
8 are arranged so as to be orthogonal to each other on the rotation center line O, so that the outputs A and B of the first and second Hall elements 7 and 8 are output.
Is a sine wave having a phase difference of 90 degrees, and detects the rotation angle using the steepest one of the outputs A and B of the first and second Hall elements 7 and 8, thereby detecting the rotation angle over the entire rotation angle range. High sensor output resolution can be obtained, and the detection accuracy can be increased.

However, the angle of intersection is not limited to 90 degrees, but may be 80 degrees or even 10 degrees, but the rotation angle can be detected although the detection accuracy is deteriorated.

Further, by using the first and second Hall elements 7 and 8 as the magnetic flux density detecting section 10 and using inexpensive permanent magnets 4 and 5 as the magnetic circuit constituting section 11,
Product cost can be reduced.

It should be noted that an electromagnet composed of a coil may be used instead of the permanent magnet as the magnetic circuit constituting section 11.

It is apparent that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a plan view of a rotation angle sensor according to an embodiment of the present invention.

FIG. 2 is a side view of the rotation angle sensor.

FIG. 3 is a graph showing sensor output characteristics.

[Explanation of symbols]

 4,5 Permanent magnet 7,8 First and second Hall element 10 Magnetic flux density detector 11 Magnetic circuit component

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F063 AA35 DA01 DA05 DA14 DA24 DB07 DC08 DD03 GA52 KA01 LA03 NA06 2F077 AA25 AA27 JJ02 JJ08 JJ23 NN17 PP12 QQ05 TT06 TT42

Claims (5)

[Claims] A first Hall element and a first Hall element which intersect each other on a center line of rotation of the magnetic circuit component; A rotation angle sensor comprising a two-hole element and configured to detect a rotation angle of a magnetic flux density detection part with respect to a magnetic circuit constituent part based on outputs of the first and second hall elements. 2. The rotation angle sensor according to claim 1, wherein said first and second Hall elements are orthogonal to each other. 3. The method according to claim 1, wherein the first and second signals are used to detect a rotation angle.
The rotation angle sensor according to claim 1, wherein the output of the second Hall element that has a larger output change with respect to the rotation angle is used. 4. The apparatus according to claim 1, wherein a rotation angle region is determined by using one of the outputs of said first and second Hall elements having a smaller voltage change with respect to a rotation angle. A rotation angle sensor according to one of the above. 5. The rotation angle sensor according to claim 1, wherein permanent magnets having mutually opposite polarities are used as said magnetic circuit constituting part.