JP2002350179A - Rotation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation detector which suppresses the dislocation of magnetism collecting parts so as to detect a rotation precisely and whose detection sensitivity is not lowered. SOLUTION: A magnetism collecting parts 15a and 15b are formed in which a Hall element 13a and a Hall element 13b are arranged on the back side as viewed from the side of a rotating body 11, a slit 15c is formed which is bored and formed so as to be extended in the direction of the shaft of the rotating body 11, and the part 15a and the part 15b are connected by connection parts 15d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for detecting the rotation speed of a rotating body made of a magnetic material using a plurality of Hall elements.

[0002]

2. Description of the Related Art A rotating member made of a magnetic material is opposed to an outer peripheral portion of the rotating member.
There is an arrangement in which two Hall elements are arranged, and a bias magnet is arranged on the back side of these two Hall elements so as to apply a bias magnetic field to each Hall element, for example, as disclosed in Japanese Patent No. 3008861. There is a rotation detection device.
In this device, a magnetic flux collecting section divided into the same number as the number of Hall elements is provided between a plurality of Hall elements to which a bias magnetic field is applied by a bias magnet and a rotating body, one each facing the front surface of each Hall element. So that the magnetic flux of the bias magnet reaches the rotating body via each magnetic flux collecting part. According to this device, since a magnetic flux collecting portion is provided on the front surface of each of the plurality of Hall elements, the magnetic flux collecting portion reduces the leakage magnetic flux, and can increase the magnetic flux linked to the Hall element. The gap can be increased.

[0003]

However, in the above-described conventional rotation detecting device, it is necessary to dispose a plurality of magnetic flux collecting parts in the housing, and the positional deviation between the magnetic flux collecting parts and the position between the magnetic flux collecting parts and the magnets are required. There is a risk that misalignment is likely to occur and accurate detection cannot be performed. Further, in order to suppress the positional deviation between the magnetic flux collecting parts, special jigs and tools are required at the time of manufacturing, which leads to an increase in the number of manufacturing steps and an increase in the cost of the rotation detecting device. Furthermore, according to the undivided magnetic flux collecting unit shown as a comparative example in the above-described conventional rotation detecting device, the positional deviation between the magnetic flux collecting units does not occur, but the detection sensitivity is extremely reduced.

An object of the present invention is to provide a rotation detecting device capable of performing accurate detection while suppressing a positional deviation between magnetic flux collecting portions and not reducing the detection sensitivity. .

[0005]

According to a first aspect of the present invention, there is provided a rotating body made of a magnetic material in which convex portions and concave portions are alternately formed on an outer peripheral portion. A plurality of Hall elements opposed to an outer peripheral portion of the rotator and arranged in a rotation direction of the rotator; a bias magnet disposed on a back side of the plurality of Hall elements as viewed from the rotator; In a rotation detecting device including a Hall element and a housing accommodating the bias magnet, and a magnetic flux collecting pole disposed in the housing between the plurality of Hall elements and the rotating body, the magnetic flux collecting pole is Rotation detection, comprising: a magnetic flux collecting portion in which the plurality of Hall elements are arranged on the back side as viewed from the rotating body side; and a slit portion formed to extend in the rotation axis direction of the rotating body. The device was configured.

According to the first aspect of the present invention, since the magnetic flux collecting portion facing each Hall element is formed integrally,
Accurate detection is possible without any displacement of the magnetic flux collecting parts. Furthermore, the magnetic flux collecting part is divided by the slit part corresponding to each Hall element, and the magnetic flux distribution can be made independent for each Hall element. And a good detection sensitivity is ensured.

Next, as set forth in claim 2, the rotation detecting device is preferably characterized in that the magnetic flux collecting pole is made of a resin containing a magnetic material and is formed integrally with the housing.

According to the second aspect of the present invention, since the magnetic flux collecting pole made of the magnetic material-containing resin is integrally formed with the housing, the manufacturing is extremely easy and a low-cost rotation detecting device can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to embodiments. 1 and 2 show a rotation detecting device according to a first embodiment of the present invention. FIG. 2 is a projection view of FIG. 1 as viewed from the rotating body 11 side.

The rotation detecting device according to the first embodiment has an A
T (automatic transmission) rotor or wheels rotate integrally with the outer periphery of the protrusion 1
Steel rotating body 11 having alternating 1a and recess 11b
And a detector 5 arranged to face the outer periphery of the rotating body 11.

The detector 5 includes a terminal portion 7a1 and a mounting portion 7
The housing 7 includes a main body 7a having a2 and a detector 7b formed separately from the main body 7a and integrated with the main body 7a by fusion.

The main body 7a of the housing 7 on which the O-ring 21 is mounted is inserted into a mounting hole (not shown) on the vehicle body side, and the mounting portion 7a2 is fixed to the vehicle body by a bolt, so that the detector 5 Is fixed to the vehicle body.

The detecting section 7b includes a bias magnet 14 for generating a bias magnetic field, a Hall IC 12 in which two Hall elements 13a and 13b and a signal processing circuit (not shown) are packaged, and a capacitor connected to the Hall IC 12. (Not shown) by resin molding. In addition, a magnetic flux collecting pole 15 made of a magnetic material-containing resin is integrated with an end face of the detecting unit 7b on the rotating body 11 side. In addition, the integration of the magnetic flux collecting pole 15 and the detection unit 7b is as follows.
The magnetic flux collecting pole 15 may be integrally molded at the time of resin molding of the detection unit 7b, or may be formed by fusion or adhesion.

The magnetic flux collecting pole 15 made of a magnetic material-containing resin is formed in a disk shape, and a slit portion 15c is formed at a central portion thereof so as to extend in the rotation axis direction of the rotating body. Further, the slit portion 15c is provided in the first Hall element 1
3a, the first magnetic flux collecting portion 15a and the second Hall element 13
The second magnetic flux collecting portion 15b opposing the second magnetic flux collecting portion 15b and the coupling portion 15d coupling the first magnetic flux collecting portion 15a and the second magnetic flux collecting portion 15b are formed.

Behind the magnetic pole 15 (upper in FIG. 1), a first Hall element 13a, a second Hall element 13b and a Hall IC 12 are arranged.
Behind 2 is disposed a bias magnet 14 for generating a bias magnetic field.

The Hall IC 12 includes a first Hall element 13a and a second Hall element 13b symmetrically arranged with respect to the slit portion 15c, and a differential amplifier for differentially amplifying the output of the first Hall element 13a and the second Hall element 13b. A dynamic amplification circuit, a trigger circuit for waveform shaping by comparing a differential output with upper and lower thresholds, and a signal processing circuit including a temperature compensation circuit and the like are packaged by resin molding.

The rotation detecting device constructed as described above operates as follows.

A first Hall element 13a and a second Hall element 13b are arranged in a bias magnetic field formed between the bias magnet 14 and the rotating body 11, and when the rotating body 11 rotates, its convex portion 11a and concave portion 11b alternately opposes each Hall element, and the magnetic flux linked to each Hall element repeatedly increases and decreases. Thus, a pulse signal having a frequency corresponding to the rotation speed of the rotating body 11 is output from each Hall element.

In this embodiment, the first Hall element 1
The first magnetic flux collecting portion 15a of the magnetic flux collecting pole 15 is arranged at a position facing the second Hall element 13b.
A magnetic flux collecting portion 15b is arranged, and the magnetic flux of the bias magnet 14 is supplied to the rotating body 1 via the first magnetic flux collecting portion 15a and the second magnetic flux collecting portion 15b.
1 so that the leakage flux is small,
The gap (detection gap) between the Hall element and the rotating body 11 can be increased.

Further, since the magnetic flux collecting portion is opposed to each Hall element, the magnetic flux distribution can be made independent for each Hall element, and the magnetic flux distribution between each Hall element is prevented from being averaged. You.

By the above synergistic effect, the output difference between the first Hall element 13a and the second Hall element 13b can be increased to improve the detection accuracy, and the detection gap can be increased. It is possible to reduce the influence of the body axis deviation and the assembly error on the output of each Hall element, and it is possible to relax the control of the dimensional accuracy and the assembly accuracy of each part, thereby obtaining a low-cost rotation detection device. .

Further, the magnetic flux collecting pole 15 includes a first magnetic flux collecting section 15a.
And the second magnetic flux collecting portion 15b are connected to each other by a coupling portion 15d, so that accurate detection can be performed without any displacement between the magnetic flux collecting portions.

Next, a second embodiment of the present invention will be described with reference to FIGS.
It will be described based on FIG. FIG. 4 is a sectional view of the rotating body 11 shown in FIG.
It is the partial projection view seen from the side. In FIGS. 3 and 4, the same or equivalent members and parts as those in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS. 1 and 2, and duplicate description will be omitted.

The magnetic pole 115 made of a magnetic material-containing resin is
A slit portion 115c is formed in a substantially circular shape and extends in the rotation axis direction of the rotating body at a central portion of the end face facing the rotating body 11.

The first magnetic flux collecting section 115a includes a first magnetic flux collecting end 115a1 facing the rotating body 11 and a first magnetic flux collecting section 115b surrounding the detecting section 7b.
And a second magnetic flux collecting section 115b.
Is composed of a second magnetic flux collecting end 115b1 facing the rotating body 11 and a second magnetic collecting cylinder 115b2 surrounding the detecting section 7b.
Further, the first magnetic flux collecting portion 115a and the second magnetic flux collecting portion 115b are integrated by a connecting portion 115d.

The slit portion 115c includes a first magnetic flux collecting end 115a1, a second magnetic flux collecting end 115b1 and a connecting portion 11c.
It is formed so as to be surrounded by 5d.

In this embodiment, the first Hall element 1
3a, the first magnetic flux collecting end 11 of the magnetic flux collecting pole 115
5a1 is arranged, the second magnetic flux collecting end 115b1 is arranged at a position facing the second Hall element 13b, and the magnetic flux of the bias magnet 14 is applied to the first magnetic flux collecting end 115a1 and the second magnetic flux collecting section 1
Since the magnetic flux reaches the rotating body 11 via the contact 15b1, the leakage magnetic flux is small, and the gap (detection gap) between the Hall element and the rotating body 11 can be increased.

Further, since the magnetic flux collecting portion is opposed to each Hall element, the magnetic flux distribution can be made independent for each Hall element, and the magnetic flux distribution between each Hall element is prevented from being averaged. You.

[0029]

According to the present invention, it is possible to provide a rotation detecting device capable of performing accurate detection while suppressing the positional deviation between the magnetic flux collecting portions and not reducing the detection sensitivity.

[Brief description of the drawings]

FIG. 1 is a front view of a rotation detecting device according to a first embodiment of the present invention.

FIG. 2 is a projection view as viewed from a rotating body 11 side in FIG.

FIG. 3 is a front view of a rotation detection device according to a second embodiment of the present invention.

FIG. 4 is a partial projection view as viewed from the rotating body 11 in FIG. 3;

[Explanation of symbols]

 7 Housing 11 Rotation 11a Convex part 11b Concave part 13a, 13b Hall element 14 Bias magnet 15, 115 Magnetic pole 15a, 15b, 115a, 115b Magnetic pole 15c, 115c Slit

Continued on front page F term (reference) 2F063 AA35 BA09 BD16 CA21 DA05 EA03 GA52 GA67 GA69 GA79 KA02 KA04 2F077 CC02 NN03 NN21 PP12 QQ01 VV02

Claims (2)

[Claims] 1. A rotating body made of a magnetic material in which convex portions and concave portions are alternately formed on an outer peripheral portion, and a plurality of holes opposed to the outer peripheral portion of the rotating body and arranged in a rotating direction of the rotating body. An element, a bias magnet disposed on the back side of the plurality of Hall elements as viewed from the rotating body side, and a housing for housing the plurality of Hall elements and the bias magnet;
In a rotation detection device including a magnetic flux collecting pole disposed in the housing between the plurality of Hall elements and the rotating body, the magnetic flux collecting pole has a plurality of Hall elements on a back side as viewed from the rotating body side. A rotation detecting device, comprising: a magnetic flux collector disposed therein; and a slit formed to extend in a rotation axis direction of the rotating body. 2. The rotation detecting device according to claim 1, wherein the magnetic flux collecting pole is made of a resin containing a magnetic material and is formed integrally with the housing.