JP3269307B2 - Pickup sensor and vehicle speed detection device using pickup sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickup sensor for moving a magnetic flux farther by two magnets joined so that the same magnetic poles face each other, and a vehicle speed detecting apparatus using the pickup sensor.

[0002]

2. Description of the Related Art Conventionally, as an example of converging a magnetic flux which diffuses and leaks from a bias magnet into a space, for example, Japanese Utility Model Application
JP-A-191967 and JP-A-3-10258.

The above Japanese Utility Model Publication No. 60-191967 will be described with reference to FIG. In the rotating body sensor, a magnet ring 105 concentrically positioned with the magnet 103 is magnetized on the outer periphery of the tip of the magnet 103 in a non-magnetic case 101. The magnet ring 105 is fixed and held by the case 1. The magnetization direction of the magnet ring 105 is determined by the magnetic pole (N pole) at the tip of the magnet 103.
The magnetic pole (N pole) having the same polarity as that described above is used as the inner circumference, and the other pole (S pole) is used as the outer pole. Thus, the magnetic flux leaking from the tip of the magnet 103 is focused.

On the other hand, Japanese Utility Model Laid-Open Publication No. Hei 3-10258 discloses FIG.
3 as shown in the sectional view. Pickup sensor 11
Reference numeral 1 denotes a stepped portion formed by partially cutting out a surface of the pickup portion of the pole piece 113 opposite to a portion facing the tone wheel 115, and a magnet piece 119 made of a permanent magnet for regulating the direction of magnetic flux is formed here. Are bonded and fixed. Since the magnet piece 119 has the N pole at the joint surface of the permanent magnet 121 with the pole piece 113, the surface facing the tone wheel 115 is set to the N pole, and the outer surface side is set to the S pole. Thereby, the magnet piece 11
At the end of the coil No. 9 on the coil 123 side, a line of magnetic force a wrapping around from the joint surface with the pole piece 113 to the outer surface is generated. The line of magnetic force a is generated from the original permanent magnet 121 to the pole piece 1.
13, the direction of the magnetic field line A which is directed toward the tone wheel 115 via the magnet 13 is restricted, and the direction of the magnetic flux which the magnetic field line A tends to leak through the magnet piece 119 is restricted.
5 could be increased in magnetic flux density.

[0005]

However, in Japanese Utility Model Laid-Open No. 191967/1985, it is not clear how the magnet ring 105 is magnetized on the outer periphery of the tip of the magnet 103. If the magnet ring 10
Even if the magnet 5 can be magnetized, the effect of causing the leakage magnetic flux to fly farther in the direction of the gear-shaped magnetic body 107 facing the cylindrical permanent magnet 103 is small, and the distance between the surface of the magnet 103 and the gear-shaped magnetic body 107 is reduced. More than a predetermined distance, for example, 2 mm
In the above case, the effect of the leakage magnetic flux density on the surface of the gear-shaped magnetic body 107 is not observed.

On the other hand, in Japanese Utility Model Laid-Open No. Hei 3-10258, a magnet piece 11 provided at the tip of a pole piece 113 is disclosed.
7 has the effect of slightly increasing the leakage flux to the tone wheel 115 side. However, since the magnetic flux leaks from the S pole side of the magnet piece 117, the magnetic flux leaking to the tone wheel 115 is concentrated at one point, but the magnetic flux is not increased.

[0007] The present invention has been made in view of such a conventional problem, and an object of the present invention is to join two magnets so that the same magnetic poles face each other, so that a leakage magnetic flux is made to fly farther. It is an object of the present invention to provide a pickup sensor capable of applying the pickup sensor and a pickup speed sensor using the pickup sensor, which increases the amount of leakage magnetic flux passing through the pickup sensor and improves the detection accuracy of the rotational position of the gear rotor.

[0008]

In order to achieve the above object, a first aspect of the present invention is directed to a first aspect of the present invention, wherein two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other; A back yoke arranged side by side on the same magnetic pole and a different magnetic pole side facing the two magnets; and a back yoke arranged adjacently on an extension of a gap where the two magnets are joined. The gist of the present invention is to provide a magneto-electric conversion element that converts a magnetic flux emitted by the repulsion of the facing magnetic poles into a current, and a yoke that focuses the magnetic flux emitted to the magneto-electric conversion element on the magneto-electric conversion element.

According to a second aspect of the present invention, there is provided a rotating gear rotor, a yoke disposed opposite to a peak and a valley of the gear rotor to converge magnetic flux in a certain direction, and each of the yokes. A magneto-resistive element, which is disposed opposite to each of the two ends and whose resistance value changes due to a change in magnetic flux, and an adhesive such that the same magnetic pole faces a substantially central extension between the magneto-resistive elements. The gist is to provide two magnets joined with a predetermined gap and a back yoke arranged side by side on the same magnetic pole and a different magnetic pole side facing the two magnets.

According to a third aspect of the present invention, there are provided two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and magnetic poles different from the same magnetic poles facing the two magnets. A back yoke juxtaposed on the side, and disposed adjacently on an extension of a gap where the two magnets are joined,
A magneto-electric conversion element that converts the two magnets into a current by a change in magnetic flux that is blown by the repulsion of the same magnetic pole facing each other,
A yoke for converging the magnetic flux that is blown by the magnetoelectric conversion element to the magnetoelectric conversion element, and a yoke opposite to the magnetoelectric conversion element on the extension of the gap where the two magnets are joined via the two magnets In addition, the gist includes the same magnetic poles of the two magnets and a magnet joined so that the same magnetic poles face each other.

According to a fourth aspect of the present invention, there are provided two magnets which are joined by an adhesive with a yoke sandwiched between them so that the same magnetic poles face each other, and the two magnets which are clamped by the yoke. A back yoke juxtaposed to the same magnetic pole and a different magnetic pole side of the two magnets; and a back yoke disposed adjacently to an extension of the yoke sandwiched between the two magnets, and the two magnets face each other. A magneto-electric conversion element that converts to a current by a change in magnetic flux that is blown off by the repulsion of the magnetic pole, and a yoke other than the surface of the yoke sandwiched between the two magnets and the yoke other than the surface on the magneto-electric conversion element side; And a non-magnetic material having a shape that narrows the end of the yoke on the magnetoelectric conversion element side.

[0012]

[0013]

[0014]

According to the first aspect of the present invention, two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and the same magnetic poles facing the two magnets are provided. A back yoke juxtaposed to different magnetic poles, and a back yoke arranged adjacently over an extension of a gap where the two magnets are joined, and a magnetic flux emitted by the repulsion of the same magnetic pole facing the two magnets. By providing a magneto-electric conversion element that converts the current into a current by a change and a yoke that focuses the magnetic flux that is emitted to the magneto-electric conversion element on the magneto-electric conversion element, the two magnets are forcibly joined to repel the same magnetic pole. , It is possible to fly the leakage magnetic flux farther.

According to a second aspect of the present invention, there is provided a rotating gear rotor, a yoke disposed opposite to a peak and a valley of the gear rotor to focus a magnetic flux in a certain direction, and a yoke provided at both ends of the yoke. A magnetoresistive element, which is disposed to face and whose resistance value changes due to a change in magnetic flux, is joined with a predetermined gap by an adhesive so that the same magnetic pole faces a substantially central extension between the magnetoresistive elements. And the back yoke arranged side by side on the same magnetic pole and a different magnetic pole side facing the two magnets, the rotational position of the gear rotor by at least two sets of two magnets can be adjusted. Since the detection is performed, the pickup sensor can be applied to increase the amount of leakage magnetic flux, thereby improving the detection accuracy of the rotational position of the gear rotor.

According to a third aspect of the present invention, two magnets are joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and the two magnets are juxtaposed on a magnetic pole side different from the same magnetic pole facing the two magnets. And a back yoke which is disposed adjacent to the extension of the gap where the two magnets are joined, and which converts the two magnets into a current by a change in a magnetic flux which is blown off by repulsion of the facing same magnetic pole. A conversion element, a yoke for converging magnetic flux emitted to the magnetoelectric conversion element to the magnetoelectric conversion element, and the two magnets with respect to the magnetoelectric conversion element on an extension of a gap where the two magnets are joined. The same magnetic pole of the two magnets and a magnet joined so that the same magnetic poles face each other are provided on the opposite side via the intermediary, so that the magnetic flux due to the repulsion of the same magnetic pole causes the two magnets to move to the magnetoelectric conversion element. Joined to the other side through Since further repelled by the same poles of the magnets that can skip flux leakage in the direction of the magneto-electric conversion element more distant.

According to a fourth aspect of the present invention, there are provided two magnets which are joined by an adhesive with a yoke sandwiched between them so that the same magnetic poles face each other, and the same two magnets which are sandwiched by the yoke. A back yoke juxtaposed on a magnetic pole side different from the magnetic poles, and a back yoke arranged adjacent to an extension of the yoke sandwiched between the two magnets, and are blown by repulsion of the same magnetic poles facing the two magnets. And a yoke other than the surface of the yoke sandwiched between the two magnets and the yoke other than the surface of the yoke on the magnetoelectric conversion element side. Since the magnetic flux is focused on the end on the side of the magneto-electric conversion element by providing the non-magnetic material having a shape that narrows the end of the yoke, the leakage magnetic flux is made to fly farther in the direction of the magneto-electric conversion element. Can be.

[0018]

[0019]

[0020]

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

FIG. 1 is a cross-sectional view showing an overall configuration of a pickup sensor according to a first embodiment of the present invention and a vehicle speed detecting apparatus to which the pickup sensor is applied.

In FIG. 1, the magnetic pickup 1 has a sensor housing 3 covering the entire housing of the magnetic pickup 1. A magnet unit 5 is provided at a substantially central portion in the sensor housing 3. The magnet unit 5 includes a permanent magnet (hereinafter, referred to as a magnet) 7 disposed such that the center side of the sensor housing 3 is the N pole and the S pole different from the N pole is the outer surface side, and the magnet 7. And a permanent magnet (hereinafter, referred to as a magnet) 9 that is joined so that the N pole of the same magnetic pole faces the S pole, and an S pole different from the N pole is disposed on the outer surface side. I have. The magnet unit 5 is forcibly joined with an adhesive in order to cause repulsion of magnetic flux between N poles, which are the same magnetic pole of the magnet 7 and the magnet 9. Further, the magnets 7 and 9 of the magnet unit 5 have a large energy product when magnets need to be miniaturized due to size restrictions of the magnetic pickup 1, such as samarium / cobalt magnets and neodymium / iron / boron magnets. Rare earth magnets are suitable. In the first embodiment, such a rare earth magnet is used.
It has a size of × 2 × 4 mm. On the other hand, when it is not necessary to reduce the size of the magnet unit 5, an inexpensive magnet having a small energy product such as an alnico magnet or a humulite magnet is used.

At a predetermined distance (gap) between the same magnetic poles of the magnet 7 and the magnet 9 which are forcibly joined to the magnet unit 5,
The adhesive 11 is filled. Accordingly, an effect of flying the magnetic flux leaking from the joint surface farther is generated according to the size of the joint surface of the magnets 7 and 9 to be joined. The gap between the magnet 7 and the magnet 9 that makes the leakage magnetic flux fly farther is 0.
6 to 1.2 mm.

A back yoke 13 is arranged in contact with the magnet 7 on the left S pole side in the drawing, and a back yoke 15 is arranged in contact with the magnet 9 on the right S pole side in the drawing. Have been. The back yokes 13 and 15 are composed of the magnet 7 and the magnet 9.
It has the effect of suppressing the leakage flux from the side surface (the back and front sides of the paper in FIG. 1) out of the leakage flux from the joint surface with the material, and a material having a large magnetic permeability is desirable. For example, an inexpensive SIOC material Is appropriate. When the back yokes 13 and 15 have the same length as the left and right side surfaces of the magnets 7 and 9 in the drawing, the magnetic flux leaking from the joining surface of the magnets 7 and 9 is removed from the adhesive 11 in the vertical direction in the drawing. Since the leakage magnetic flux component is pulled by the back yokes 13 and 15 in the horizontal direction in the figure, the originally used vertical magnetic flux is weakened. For this reason, in the present embodiment, the back yokes 13, 15
The length of the side surface in the vertical direction is shorter than the length of the magnets 7 and 9 in the vertical direction. The back yokes 13, 15
Is, for example, 3 × 1.5 × 3 mm.

A resin component 17 covering the side surfaces of the back yoke 13 of the magnet unit 5 from the upper surfaces of the magnets 7 and 9 and the side surface of the back yoke 15 is a circuit for fixing a holder of the magnet unit 5 and a magnetoelectric conversion element 19 described later. It is also used as a substrate. A wiring pattern is formed on the upper surface of the resin component 17 in the drawing. Magnetoelectric conversion element 1 provided on extension of adhesive 11 via resin part 17
Numeral 9 causes the magnetic flux to fly against the surface of the built-in magnetic sensing element (not shown) due to the repulsion of the N pole of the magnet 7 of the magnet unit 5 and the N pole of the magnet 9. Further, the magnetoelectric conversion element 19 includes a Hall element having a Hall element having a Hall effect therein, a Hall IC, or a magnetoresistance element having a magnetoresistance effect. A yoke 21 is disposed substantially at the center of the upper surface of the magnetoelectric conversion element 19 in the drawing. The yoke 21 is provided to attract the leakage magnetic flux, which is blown by the repulsion of the two magnets 7, 9 by the same magnetic pole, toward the magneto-electric conversion element 19. It is arranged on the upper surface of the magnetoelectric conversion element 19 so as to be focused on the element 19. The material of the yoke 21 is the same as that of the back yokes 13 and 15 described above.

A rubber bushing 23 screwed into a resin 29 to be described later at the center of the lower end of the sensor housing 3.
The wire harness 25 described later is penetrated. The rubber bushing 23 is made of an elastic material such as rubber to prevent disconnection due to bending of the wire harness 25. The outer peripheral surface of the rubber bushing 23 is formed in a wavy shape in order to prevent water from entering the inside of the magnetic pickup 1. A wire harness 25 bent from the rubber bushing 23 to the right in the drawing and bent from the lower right end of the resin component 17 to the side surface of the resin component 17 is connected to a terminal 27 described later.
Are fixed by being soldered to a resin component 17 also serving as a circuit board. Also, the wire harness 25
Is electrically connected to the terminal 27 in the upper part of the figure via the element wire 28. The gap inside the sensor housing 3 is filled with the resin 29 by potting a resin material.

FIG. 2A is a plan view in which the shapes of the back yokes 13 and 15 of the first embodiment are modified, and FIG. 2B is a front view in which the shapes of the back yokes 13 and 15 are modified. Show.
The widths of the back yokes 13 and 15 in the plane shown in FIG. As shown in FIG. 2B, the back yokes 13, 15 which are arranged side by side in contact with the side surfaces of the magnets 7 and 9 in the figure respectively obliquely outward from the portions joined to the magnets 7, 9. It has a notched and inclined shape. The effects of the modification shown in FIGS. 2A and 2B are the same as those of the first embodiment.

FIG. 2C shows a modification of the magnet unit 5 of the first embodiment.

The lower ends of the magnets 7 and 9 provided in the magnet unit 5 of FIG. 1 are shorter than the length of the magnet unit 5 of the magnets 7 and 9 and have the same magnetic poles facing the same magnetic pole. A magnet 31 facing the N pole is provided on the 9th side. Since the arrangement of the magnet 31 causes the magnetic flux leaking from the magnets 7 and 9 facing the same magnetic pole to be repelled by the N pole of the magnet 31, the magnetic flux density decreases in the direction of the magnetoelectric conversion element 19 (not shown) on the upper side in the figure. High magnetic flux will be skipped. The gap between the magnets 7 and 9 and the magnet 31 is
1 and the gap between the magnets 7 and 9 is 0.6 to 1.2 m, like the gap between the magnet 7 and the magnet 9 in the first embodiment.
m.

The production procedure of the first embodiment will be described with reference to the production steps shown in FIG.

First, the magnets 7 and 9 and the yoke are joined (ST1), and N, which is the same magnetic pole of the two magnets 7 and 9, is used.
The poles are forcibly joined to face each other and the magnet unit 5
Is created (ST2).

On the other hand, the case is formed by plating a metal foil from the upper surface to the right surface in the figure. Further, the case may be manufactured, for example, by bonding a synthetic resin foil to be an insulating layer to a nonmagnetic metal surface of aluminum, and bonding the synthetic resin to form a circuit pattern with a copper foil on the synthetic resin. Good (ST3).

A Hall IC or an MR element, which will be described later, and a chip resistor are soldered to the upper surface of the case in the drawing to be joined to the case (ST4).

On the other hand, the rubber bush 23 is inserted into a predetermined portion of the wire harness (ST5). After the insertion, the terminal 27 is inserted into the end of the wire harness (ST6).

Next, the terminal 27 is soldered to the case,
The wire harness is joined (ST7). After the joining, the above-described magnet unit 5 is assembled to produce a rotation sensor unit (ST8).

FIG. 4 is a sectional view showing the entire structure of the second embodiment of the present invention.

The second embodiment is an application of the first embodiment. A vehicle speed detecting device using an MR (magneto-resistive) element having a magnetoresistive effect whose resistance changes with a magnetic field as a magnetoelectric conversion element. This is an example applied to

The above-mentioned vehicle speed detecting apparatus measures the rotational position of the gear to be measured with higher resolution by using two sets of the magnet units of the first embodiment.

First, as described with reference to FIG. 1, the magnet units 5a disposed on the left side of the approximate center of the figure are forcibly joined so that the N poles of the same magnetic poles of the magnets 7a and 9a face each other. The gap between the magnet 7a and the magnet 9a is filled with an adhesive 11a. On the other hand, the magnet unit 5a
Magnet unit 5b disposed on the right side in the figure
Are forcibly joined so that the N poles of the same magnetic pole of the magnets 7b and 9b face each other, and the gap between the magnet 7b and the magnet 9b is filled with an adhesive 11b. The adhesive 11a
In the upper part of the adhesive 11b in the figure, patterns (hereinafter, referred to as patterns) 33a to 35b of four magnetoresistive elements composed of MR elements are formed. The yoke 21a is provided substantially at the center between the patterns 33a, 35a on the magnet unit 5a side, and the pattern 33 on the magnet unit 5b side.
A yoke 21b is disposed substantially at the center between b and 35b. A gear rotor 37 to be measured is provided in the upper part of the sensor housing 3 joined to the yoke 21a and the yoke 21b in the drawing. The gear rotor 37 rotates counterclockwise.

The pattern 33a on the magnet unit 5a side
The yoke 21a disposed substantially at the center of the pattern 35a faces the peak 39a of the gear rotor 37, and the yoke 21b disposed substantially at the center of the pattern 33b and the pattern 35b of the magnet unit 5b. Is the gear rotor 37
Are arranged to face the valley 39d. Further, even when the gear rotor 37 rotates, the yoke 21a keeps the gear rotor 3
The ridge 7 and the yoke 21b are disposed to face the valleys of the gear rotor 37, respectively. That is, the yokes 21a and 21a
The reason why b is disposed so as to face the peak or valley of the gear rotor 37 is to improve the resolution of detecting the rotational position of the gear of the gear rotor 37. When the magnetic flux is blown to the peak of the gear rotor 37, each pattern detects a strong resistance value,
When the magnetic flux is blown to the valley of the gear rotor 37, each pattern detects a weak resistance value.

The patterns 33a and 35a on the adhesive 11a of the magnet unit 5a are formed at positions where the phases are shifted by 90 ° with respect to the gear pitch of the gear rotor 37. Similarly, the patterns 33b and 35b on the adhesive 11b of the magnet unit 5b are formed at positions where the phases are shifted by 90 ° with respect to the gear pitch of the gear rotor 37. The patterns 33a and 35a and the patterns 33b and 3
Each of the two patterns 5b is formed as a set of so-called detectors for detecting the rotational position of the gear rotor 37. The interval between the yoke 21a and the yoke 21b corresponds to 1.5 rotations of the gear rotor 37, that is, 90 ° × 6 = 540 °. In the second embodiment, the yoke 2 is used.
The distance between the gear rotor 37 and the yoke 21b is set to 1.5 of the gear rotor 37.
Although the interval corresponds to the rotation, the invention is not limited to the 1.5 rotation, but may be applied to intervals of, for example, 0.5 rotation and 2.5 rotations. Further, the two magnet units 5 of the first embodiment described above.
Can be applied as a set to the vehicle speed detection device as in the second embodiment.

Next, a plan view of the patterns 33a to 35b is shown in FIG.

In the figure, a pattern 33a, a pattern 35a, a pattern 33b, and a pattern 35b are formed in a substantially central portion of a substrate 41 in the vertical direction from the right side of the figure, which is indicated by oblique lines in the figure, in parallel with the pattern 35b. A power supply (Vcc) 43 is formed at the lower right of the substrate 41, an electrode 45 is formed at the upper right of the figure, an electrode 47 is formed at the lower left of the figure, and a GND (ground) 49 is formed at the upper left of the figure. The patterns 33a to 35b are thin film resistors of a compound semiconductor made of, for example, indium antimony. When the distance between the patterns 35a and 33b increases, the pattern may be divided into two magneto-resistive elements instead of one magneto-resistive element as shown in FIG.

As described above, in the second embodiment, two magnets forcibly joined so that the same magnetic poles face each other using a magnetoresistive element composed of four magnetoresistors (patterns). Utilizing two magnet units, the gear rotor 37
Are respectively measured. Thereby, the detection resolution of the rotational position of the gear rotor 37 can be doubled.

The third embodiment of the present invention will be described with reference to FIGS.
This will be described using (c).

FIGS. 1 and 2A show the third embodiment.
, (B) and (c), the yoke 57 is inserted into the gap between the magnet 53 and the magnet 55 which are forcibly joined so that the same magnetic poles face each other.
Is sandwiched. The upper part of the yoke 57 in the figure is
As shown in FIG. 6A, in order to use a leakage magnetic flux from a gap between the magnet 53 and the magnet 55 joined so that the N poles of the same magnetic pole face each other as a rotation sensor, the magnet 53 and the magnet 55 in the drawing are used. It is formed up to the same plane as the upper end. on the other hand,
The lower end in the figure of the yoke 57 sandwiched in the gap between the magnet 53 and the magnet 55 is shorter than the lower ends of the magnets 53 and 55. This is because the yoke 57 is sandwiched in the gap between the magnet 53 and the magnet 55, so that the magnets 5 are joined so that the same magnetic poles face each other.
This is because the magnetic flux leaking from the lower portions of the members 3 and 55 is pulled to the upper portion in the drawing via the yoke 57.

FIG. 6B is a sectional view taken along the line AA of FIG. 6A. The width of the yoke 57 is set to be equal to the width of the magnets 53 and 55 in order to eliminate the magnetic flux leaking into the space from the vertical direction in the figure with respect to the magnets 53 and 55 joined so that the N poles of the same magnetic pole face each other.
Narrower than the width. This is because the lines of magnetic force (indicated by broken lines in the figure) from the magnets 53 and 55 joined so that the same magnetic poles face each other are shown in the sectional view taken along the line AA in FIG. This is because the magnetic flux leaking from the ends of the magnets 53 and 55 is pulled inward (toward the front in the drawing).

FIG. 6C is a sectional view taken along line BB of FIG. 6A. The yoke 57 is covered with a surface sandwiched between the two magnets 53 and 55 by the non-magnetic body 63, the left and right side surfaces in the drawing, the surface of the magneto-electric conversion element (not shown), and the bottom surface in the drawing. The ends of the yoke 57 and the non-magnetic body 63 on the magnetoelectric conversion element side at the upper end in the drawing are narrowed down from the center in the drawing. Thereby, the leakage magnetic flux due to the repulsion of the same magnetic pole of the magnets 53 and 55 (not shown) is focused at the center of the upper end in the figure, and a large amount of magnetic flux is transferred from the center to the magnetoelectric conversion element 19 in the upper part of the figure. (Not shown).

With the above configuration, the magnetic flux leaking from the magnets 53 and 55 is narrowed down by the non-magnetic material 63 by sandwiching the yoke 57 in the gap between the magnets 53 and 55 joined so that the same magnetic poles face each other. You can fly stronger and farther from the edge.

The overall structure of the fourth embodiment of the present invention will be described with reference to the sectional view of FIG.

In the fourth embodiment, two magnets are forcibly joined so that the same magnetic poles face each other in the first embodiment, but the same magnetic poles are arranged in parallel in the same direction. Two magnets are forcibly joined.

First, the N pole of the same magnetic pole of the magnet 67 and the magnet 69 provided in the magnet unit 65 is placed on the magnetoelectric conversion element 19 in the upward direction in the figure, and the S pole different from the N pole is shown in the figure. It is arranged on a rubber bushing 23 side described below in a downward direction. The gap between the magnet 67 and the magnet 69 is filled with an adhesive 11.
Is filled. On the left and right side surfaces and the upper surface side of the magnet unit 65 including the magnet 67 and the magnet 69 in the drawing,
The resin part 17 is formed, which also serves as a case for the magnet unit 65 and a circuit board. An electrode pattern is formed on the surface of the resin component 17 opposite to the magnet unit 65 side, and the magnetoelectric conversion element 19 is soldered. A magneto-sensitive element 71 for detecting a magnetic flux passing therethrough is built in substantially the center of the magneto-electric conversion element 19. The air gap from the N pole faces of the magnets 67 and 69 of the magnet unit 65 to the magneto-sensitive element 71 is 0.5 to 1.
0 mm.

Next, the lower end 73 of the magnet unit 65
A rubber bushing 2 made of an elastic material such as rubber
3 are provided. A wire harness 25 that bends from the rubber bushing 23 to the right in the drawing and bends from the lower right end of the resin component 17 to the side surface of the resin component 17 is electrically connected to the terminal 27 in the upper part of the drawing via a wire 28. It is connected to the. The terminal 27 is soldered to the resin component 17 to fix the wire harness 25.

Further, the gap inside the sensor housing 3 is filled by potting the resin 29.
The magnet unit 65, the magnetoelectric conversion element 19, and the like are entirely covered with the sensor housing 3 made of a nonmagnetic metal material or a synthetic resin material. A gear rotor 75 is disposed above the sensor housing 3 in the drawing.

With the above configuration, the magnetic flux leaking from the N-pole surface near the joint surface of the two magnets 67 and 69 in which the same magnetic poles are forcibly joined in parallel in the same direction interfere with each other and the N-pole surface , And the number of magnetic fluxes passing through the magneto-sensitive element 71 of the magneto-electric transducer 19 increases.

A modification of the fourth embodiment will be described with reference to FIG.

In the fourth embodiment, the same magnetic pole is provided in the same direction on the magneto-sensitive element 71 incorporated in the magnetoelectric conversion element 19.
In contrast to the forcible joining of the magnets, the modified example has a rectangular notch groove 81 formed in the longitudinal direction of the N pole face of the magnet 79. With the above configuration, the magnetic flux from the N-pole surface of the magnet 79 away from the end portion 83 of the groove 81 is bent in the left and right directions with respect to the groove 81 from the middle of the upper part in the figure and is blown off. However, as it approaches the end 83, the leakage magnetic flux interferes with each other and is blown in a direction perpendicular to the N-pole surface of the magnet 79. Accordingly, the magnetic flux near the end 83 of the groove 81 becomes N
Since the magnetic flux is skipped in the direction perpendicular to the pole face, the magnetic flux passing through the magnetoelectric conversion element 19 (not shown) disposed above the groove 81 in the figure increases.

Here, the state of the leakage magnetic flux due to the joining state of the magnets will be described with reference to FIGS. 9 (a), 9 (b) and 9 (c). First,
FIG. 9 (a) shows the leakage flux from a single magnet having an N pole on the upper side and an S pole on the lower side. The leakage flux from the N pole is the direction of the S pole from both the left and right directions indicated by the dotted lines in the figure. It is skipped while drawing an ellipse. Next, FIG. 9B shows an N pole on the upper side of the figure,
The case where two magnets of the S pole are forcibly joined to the lower side is shown. Due to the repulsion between the N poles of the joining surfaces of the two magnets to be joined, magnetic fluxes from the N poles near the joining surface interfere with each other, and are blown farther in the vertical direction than in the case of FIG. Further, FIG. 9C shows a single magnet having a rectangular notch-like groove formed in the longitudinal direction substantially at the center of the N pole on the upper side in the figure. Due to the repulsion between the N poles at the ends of the groove, the magnetic flux from near the groove is blown far in the direction perpendicular to the N pole surface.

Next, the effect of the configuration of the present invention will be described with reference to FIG.

First, the example of the repulsion # 1 has a width of 2 mm and a height of 3 mm.
This is a configuration in which N poles, which are the same magnetic poles of two magnets having a length of 3 mm and a depth of 3 mm, are forcibly joined to each other and are joined to a gap of 0.5 mm. A wheel element is joined to the lower side of the two magnets in the figure. The example of the repulsion # 2 has a configuration in which two magnets are joined at a gap of 1 mm that is 0.5 mm wider than the configuration of the repulsion # 1. The example of the repulsion # 3 has a configuration in which a back yoke is juxtaposed on the S pole side of two magnets in which N poles are forcibly joined together so that the same magnetic pole faces each other as compared with the configuration of the repulsion # 2. . The example of the repulsion # 4 is different from the configuration of the repulsion # 3 in that two N-poles having the same magnetic pole are forcibly joined to each other, and the N-pole side of the two magnets is located above the two magnets. In this configuration, magnets are placed so as to face each other. The example of the rebound # 5 showing the present invention has a bonded 2 compared to the configuration of the repulsion # 4.
The configuration is such that a yoke 57 is provided in the gap between the two magnets and the magnet placed above the two magnets in the drawing. The gear rotor used in the experiment had a diameter of 60 mm and 25 teeth.

FIG. 11 is a graph showing experimental data of the examples of the repulsions # 1 to # 5. The horizontal axis of the graph is the bias magnetic flux (Gauss) when the air gap is 0.5 mm, and the vertical axis is the value obtained by dividing the change in magnetic flux when the air gap is 0.5 mm by the bias magnetic flux.

In the example of the repulsion # 1, the bias magnetic flux is about 2
In the case of 100 Gauss, the ratio of the magnetic flux change amount is about 0.136.
It is. In the example of the repulsion # 2, when the bias magnetic flux is about 2200 gauss, the ratio of the magnetic flux change amount is about 0.178.
In the example of the repulsion # 3, when the bias magnetic flux is about 2250 gauss, the ratio of the magnetic flux change amount is about 0.185. In the example of the repulsion # 4, when the bias magnetic flux is about 2500 Gauss, the ratio of the magnetic flux change amount is about 0.22. On the other hand, in the example of the repulsion # 5 of the present invention, when the bias magnetic flux is about 2500 gauss, the ratio of the magnetic flux change is about 0.220. As a result, the magnetic flux passing through the gear rotor of the vehicle speed detecting device to which the present invention is applied as shown in the example of the repulsion # 5 is improved, so that the detection accuracy of the rotation speed of the gear rotor can be improved.

According to the first to fourth embodiments described above, two magnets in which the same magnetic poles are forcibly joined in the same direction in parallel so that the N poles, which are the same magnetic poles, face each other are used. Therefore, even if a small bias magnet is used, the magnetic flux passing through the magnetoelectric conversion element can be secured. This allows
The size of the pickup sensor can be reduced.

As an application example of the present embodiment, the present invention is effective in a case where there is a restriction in a space for mounting a sensor, such as a wheel speed sensor for detecting the rotation speed of a bicycle wheel. Further, since the size of the magnet as the bias magnet can be reduced, an inexpensive rotation sensor can be realized.

[0065]

As described above, the first aspect of the present invention relates to two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and the same magnetic poles facing the two magnets. A back yoke arranged side by side on a different magnetic pole side,
A magneto-electric conversion element which is disposed adjacently on the extension of the gap where the two magnets are joined, and converts the current into a current by a change in magnetic flux which is blown off by repulsion of the same magnetic pole facing the two magnets; A yoke for converging the magnetic flux that flies to the magnetoelectric conversion element to the magnetoelectric conversion element,
Since the magnets are forcibly joined and the repulsion of the same magnetic pole is used, the leakage magnetic flux can be made to fly farther.

According to a second aspect of the present invention, there is provided a rotating gear rotor, yokes disposed opposite to the peaks and valleys of the gear rotor and for converging magnetic flux in a certain direction, and two ends of each of the yokes. A magnetoresistive element, which is disposed to face and whose resistance value changes due to a change in magnetic flux, is joined with a predetermined gap by an adhesive so that the same magnetic pole faces a substantially central extension between the magnetoresistive elements. And the back yoke arranged side by side on the same magnetic pole and a different magnetic pole side facing the two magnets, the rotational position of the gear rotor by at least two sets of two magnets can be adjusted. Since the detection is performed, the pickup sensor can be applied to increase the amount of leakage magnetic flux, thereby improving the detection accuracy of the rotational position of the gear rotor.

According to a third aspect of the present invention, two magnets are joined at a predetermined gap by an adhesive so that the same magnetic pole faces each other, and two magnets are juxtaposed on a magnetic pole side different from the same magnetic pole facing the two magnets. And a back yoke which is disposed adjacent to the extension of the gap where the two magnets are joined, and which converts the two magnets into a current by a change in a magnetic flux which is blown off by repulsion of the facing same magnetic pole. A conversion element, a yoke for converging magnetic flux emitted to the magnetoelectric conversion element to the magnetoelectric conversion element, and the two magnets with respect to the magnetoelectric conversion element on an extension of a gap where the two magnets are joined. The same magnetic pole of the two magnets and a magnet joined so that the same magnetic poles face each other are provided on the opposite side via the intermediary, so that the magnetic flux due to the repulsion of the same magnetic pole causes the two magnets to move to the magnetoelectric conversion element. Joined to the other side through Since further repelled by the same poles of the magnets that can skip flux leakage in the direction of the magneto-electric conversion element more distant.

According to a fourth aspect of the present invention, there are provided two magnets which are joined by an adhesive with a yoke sandwiched between them so that the same magnetic poles face each other, and the same two magnets which are sandwiched by the yoke. A back yoke juxtaposed on a magnetic pole side different from the magnetic poles, and a back yoke arranged adjacent to an extension of the yoke sandwiched between the two magnets, and are blown by repulsion of the same magnetic poles facing the two magnets. And a yoke other than the surface of the yoke sandwiched between the two magnets and the yoke other than the surface of the yoke on the magnetoelectric conversion element side. Since the magnetic flux is focused on the end on the side of the magneto-electric conversion element by providing the non-magnetic material having a shape that narrows the end of the yoke, the leakage magnetic flux is made to fly farther in the direction of the magneto-electric conversion element. Can be.

[0069]

[0070]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an entire configuration of a pickup sensor according to a first embodiment of the present invention and a vehicle speed detection device to which the pickup sensor is applied.

FIG. 2 is a diagram showing a modification of the first embodiment.

FIG. 3 is a diagram showing a manufacturing procedure of the first embodiment.

FIG. 4 is a cross-sectional view illustrating an entire configuration according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a pattern.

FIG. 6 is a cross-sectional view illustrating an entire configuration according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating an entire configuration according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a modification of the fourth embodiment.

FIG. 9 is a diagram illustrating a leakage magnetic flux of a magnet.

FIG. 10 is a diagram showing the effect of the present invention.

FIG. 11 is a diagram showing experimental data relating to the present invention.

FIG. 12 is an explanatory view showing a part of cutting in a conventional example.

FIG. 13 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic pickup 5 Magnet unit 7, 9, 67, 69 Magnet 11 Adhesive 13, 15 Back yoke 19 Magnetoelectric conversion element 33a, 33b, 35a, 35b Magnetoresistance element 37 Gear rotor 63 Nonmagnetic material 71 Magnetic sensing element 81 Groove 83 End Department

Claims (4)

(57) [Claims] 1. Two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and a back yoke juxtaposed on a magnetic pole side different from the same magnetic poles facing the two magnets. A magneto-electric conversion element that is disposed adjacently on the extension of the gap where the two magnets are joined, and converts the current into a current by a change in magnetic flux that is skipped by the repulsion of the same magnetic pole facing the two magnets; A yoke for converging the magnetic flux emitted by the magneto-electric conversion element to the magneto-electric conversion element; 2. A rotating gear rotor, a yoke disposed opposite to a peak and a valley of the gear rotor to focus magnetic flux in a fixed direction, and disposed opposite to both ends of the yoke. A magnetoresistive element having a resistance value changed by a change in magnetic flux, and two pieces joined by a predetermined gap by an adhesive so that the same magnetic pole faces a substantially central extension between the magnetoresistive elements. And a back yoke arranged side by side on the same magnetic pole opposite to the two magnets and on a different magnetic pole side. A vehicle speed detecting apparatus using a pickup sensor. 3. Two magnets joined with a predetermined gap by an adhesive so that the same magnetic poles face each other, and a back yoke arranged side by side on a different magnetic pole side from the same magnetic poles facing the two magnets. A magneto-electric conversion element that is disposed adjacent to the extension of the gap where the two magnets are joined, and that converts the two magnets into a current by a change in magnetic flux that is blown off by repulsion of the same magnetic pole facing each other; A yoke for converging the magnetic flux that is blown to the magnetoelectric conversion element to the magnetoelectric conversion element; and an opposite side to the magnetoelectric conversion element on the extension of the gap where the two magnets are joined via the two magnets. 2
And a magnet joined such that the same magnetic pole of the magnets and the same magnetic pole face each other. 4. Two magnets which are joined by an adhesive with a yoke sandwiched between them so that the same magnetic poles face each other, and magnetic poles different from the same magnetic poles of the two magnets sandwiched by the yoke A back yoke juxtaposed on the side, and a change in magnetic flux that is disposed adjacent to an extension of the yoke sandwiched between the two magnets and is repelled by repulsion of the same magnetic pole facing the two magnets. And a yoke other than the surface of the yoke sandwiched by the two magnets and the yoke other than the surface of the yoke on the magnetoelectric conversion element side, and the yoke on the magnetoelectric conversion element side. pickup sensor, characterized by comprising a non-magnetic material shaped to narrow the end portion.