JP3341518B2 - Magnetic detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detection device for detecting a movement such as a movement of an object to be detected by utilizing a resistance change of a magnetoresistive element.

[0002]

2. Description of the Related Art Conventionally, a gear proximity type rotation sensor using a magnetoresistive element has been disclosed in Japanese Patent Application Laid-Open No. 3-195970. This sensor is provided with a countermeasure against waveform breakage of the resistance change waveform. This technique will be described with reference to FIG. 20. A magnetoresistive element 21 is deposited on the substrate 20. A bias magnet 23 is mounted on one surface of the support plate 22, and a substrate 20 is mounted on the other surface of the support plate 22 perpendicularly to a magnetized surface 23 a of the bias magnet 23. Further, the magnetic vector (magnetized surface 2) generated by the magnetoresistive element 21 from the bias magnet 23 on the substrate 20.
A predetermined angle (FIG. 20 ) with respect to a component BY in a direction perpendicular to 3a.
(45 degrees). And the gear 24
The change in the direction of the magnetic vector BY due to the rotation of the element is detected by the magnetoresistive element 21 as a change in resistance.

[0003]

However, the substrate 20
(Magnetoresistive element 21) to the magnetized surface 23 of the bias magnet 23
a, the sensor becomes larger in the direction perpendicular to the magnetized surface 23a of the bias magnet 23.

An object of the present invention is to provide a magnetic detection device which can be reduced in size and can prevent the resistance change waveform from breaking.

[0005]

According to a first aspect of the present invention, there is provided a bias magnet having a magnetized surface facing a detection target having a magnetic material and generating a bias magnetic field toward the detection target. A magnetoresistive element disposed in a bias magnetic field, wherein the magnetoresistive element causes a change in resistance due to a change in a bias magnetic field from the bias magnet to the detection target accompanying the movement of the detection target. In the magnetic detection device, the magnetic resistance element is arranged in parallel with the magnetized surface of the bias magnet, and the magnetic vector in the bias magnetic field that is parallel to the magnetized surface of the bias magnet and goes to the outer peripheral side. Alternatively, they are arranged symmetrically at a predetermined angle with respect to the magnetic vector inward from the outer peripheral side, and furthermore, are arranged in a rotational direction of the detection target.
The gist of the present invention is a magnetism detecting device which is arranged at right angles to each other and detects a change in the magnetic vector. According to a sixth aspect of the present invention, there is provided a bias magnet having a magnetized surface facing a detection target having a magnetic material and generating a bias magnetic field toward the detection target, and a magnetoresistive element in the bias magnetic field. And the magnetoresistive element is arranged in parallel with the magnetized surface of the bias magnet, and the magnetic vector parallel to the magnetized surface of the bias magnet in the bias magnetic field and directed to the outer peripheral side or It is symmetrically arranged at a predetermined angle with respect to the magnetic vector inward from the outer peripheral side, and furthermore , the magnetic vector is inclined in the rotational direction of the detection target.
Disposed perpendicularly to each other, and a change in the bias magnetic field from the bias magnet to the object to be detected accompanying the movement of the object to be detected is detected by the magnetoresistive element. The gist is a method of detecting the motion of the object.

According to a second aspect of the present invention, there is provided a magnetism detecting device according to the first aspect, wherein the magnetoresistive element is disposed at an angle of about 45 degrees with respect to the magnetic vector.

According to a third aspect of the present invention, in the first or second aspect, the magnetoresistive element is set at 30 to 150 degrees or 210 to 150 with respect to the direction of movement of the detection target.
The gist is a magnetic detection device arranged at a position rotated by 330 degrees.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the magnetoresistive element is rotated by 90 degrees or 270 with respect to the movement direction of the object to be detected.
The gist is a magnetism detection device arranged at a position rotated by degrees.

According to a fifth aspect of the present invention, there is provided a magnetism detecting device according to any one of the first to fourth aspects, wherein the magnetoresistive element is disposed near an outer peripheral surface of a bias magnet.

[0010]

According to the first aspect of the present invention, when the object to be detected moves, a magnetic vector parallel to the magnetized surface of the bias magnet in the bias magnetic field and directed to the outer peripheral side or inward from the outer peripheral side. The direction of the heading magnetic vector changes. This change in the direction of the vector is detected as a resistance change by a magnetoresistive element arranged in parallel to the magnetized surface of the bias magnet. At this time, since the magnetoresistive element is arranged parallel to the magnetized surface of the bias magnet, compared with the case where the magnetoresistive element is arranged perpendicular to the magnetized surface of the bias magnet,
It becomes smaller in the direction perpendicular to the magnetized surface of the bias magnet. or,
The magnetic resistance element parallel to the magnetized surface of the bias magnet in the bias magnetic field and inclined at a predetermined angle with respect to the magnetic vector heading toward the outer periphery or the magnetic vector heading inward from the outer periphery is symmetrically tilted. And further, the detected pair
Since the elephant is arranged in a direction perpendicular to the rotation direction of the elephant and detects the change in the magnetic vector, the breakage of the resistance change waveform is prevented. According to the sixth aspect of the invention, when the detection target moves, the bias magnetic field changes accordingly. In this case, arranged in parallel to the magnetoresistive element to the magnetized surface of the bias magnet, and symmetrically arranged inclined at a predetermined angle with respect to the magnetic vector parallel to the magnetized surface, further
Since the motion of the object to be detected is detected in a state where the object is arranged in a direction perpendicular to the rotation direction of the object to be detected, a better detection method can be provided.

According to the invention described in claim 2, according to claim 1,
In addition to the effect of the invention described in the above, for the magnetic vector,
Since the magnetoresistive elements are arranged at an angle of about 45 degrees, the rate of change of resistance shows the maximum value with respect to the vector swing.

[0012] According to the third aspect of the present invention, the first aspect is provided.
Or in addition to the operation of the invention described in 2 above, the magnetoresistive element is 30 to 150 degrees or 21 degrees with respect to the movement direction of the detection target.
It is arranged at a position rotated by 0 to 330 degrees, and the rate of change in resistance of the magnetoresistive element increases.

[0013] According to the invention described in claim 4, according to claim 1 of the present invention.
In addition to the effects of the invention described in any one of (1) to (3), the magnetic resistance element is 90 degrees or 2 degrees with respect to the movement direction of the detection target.
It is arranged at a position rotated by 70 degrees, and the resistance change rate of the magnetoresistive element further increases.

According to a fifth aspect of the present invention, in addition to the function of the first aspect of the present invention, the magnetoresistive element is arranged near the outer peripheral surface of the bias magnet, and a sufficient resistance change rate is obtained. Is obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a plan view of the magnetic rotation detecting device of the present embodiment. FIG. 2 is a view taken in the direction of arrow A in FIG.

The support plate 1 has a rectangular shape. The bias magnet 2 made of a permanent magnet has a cylindrical shape, and the outer diameter of the bias magnet 2 is 7 mm. One surface of the bias magnet 2 is magnetized to the N pole, and the other surface is magnetized to the S pole. One surface of the bias magnet 2 (N-pole magnetized surface 2a) is bonded to one surface of the support plate 1.

FIG. 3 shows the N-pole magnetized surface 2 of the bias magnet 2.
The state of the line of magnetic force from a to the S-polarized surface is shown. FIG. 4 is a view taken in the direction of the arrow B in FIG. As shown in FIG. 3, at a position P1 slightly away from the N-pole magnetized surface 2a of the bias magnet 2, the magnetic vector B is parallel to the N-pole magnetized surface 2a of the bias magnet 2 and goes to the outer peripheral side. Vector B
_X and a vector _{BY in} a direction perpendicular to the N-pole magnetized surface 2a of the bias magnet 2 are synthesized. Hereinafter, the vector B _X toward the parallel and the outer peripheral side to the N-pole magnetized surface 2a of the bias magnet 2 together referred to as "N-pole magnetized surface parallel component vector", a direction perpendicular to the N-pole magnetized surface 2a of the bias magnet 2 of the vector B _Y as "N-pole magnetized surface vertical component vector".

As shown in FIG. 1, one surface of the rectangular substrate 3 is adhered to the other surface of the support plate 1.
As shown in FIG. 5, two magnetoresistive elements 4 and 5 are formed on the surface of the substrate 3 by vapor deposition. Thus, the magnetoresistive elements 4 and 5 are arranged in parallel with the N-pole magnetized surface 2a of the bias magnet 2.

The magnetoresistive elements 4 and 5 have a band shape and extend linearly. The magnetoresistive elements 4 and 5 include a bias magnet 2
Are a pair arranged in N-pole magnetized surface parallel component vector B _X direction respectively approximately plus and minus 45 degrees relative to (indicated by W in FIG. 5) in the magnetic vector B generated from. The width of each of the magnetoresistive elements 4 and 5 is 8 μm, and both the N-pole magnetized surface parallel component vector B _X and the N-pole magnetized surface vertical component vector _{BY at} the installation position of the magnetoresistive elements 4 and 5 are 100 μm.
When the value is Gauss or more, the magnetoresistive elements 4 and 5 have a saturation magnetic field strength or more.

As shown in FIG. 5, a waveform processing circuit 6 is formed on the surface of the substrate 3. In addition, as shown in FIGS.
Are provided, and the output take-out leads 9
The signal from the waveform processing circuit 6 is extracted.

On the other hand, as shown in FIG. 1, the gear 7 is a detection target having a magnetic material, and the gear 7 has a large number of teeth 8 formed thereon. The substrate 3 is arranged to face the teeth 8 of the gear 7. Further, as shown in FIG. 2, the center of the bias magnet 2 is located on the center line of the gear 7 in the thickness direction. The arrangement positions of the magnetoresistive elements 4 and 5 are as follows.
The direction is perpendicular to the gear rotation direction (a direction rotated 90 ° counterclockwise with respect to the gear rotation direction). further,
The arrangement position of the magnetoresistive elements 4 and 5 is 0.25 to 5.0 mm from the center of the bias magnet 2.

In other words, the distance from the center of the bias magnet 2 to the magnetoresistive elements 4 and 5 is determined by the thickness t of the gear 7 and the diameter of the bias magnet 2, and the deflection of the magnetic vector described later occurs. And a range not lower than the saturation magnetic field strength of the magnetoresistive elements 4 and 5.

As described above, in the magnetic circuit constituted by the bias magnet 2 to the gear 7, the surface of the magnetic resistance element 4,
The substrate 3 on which the vapor deposition 5 is deposited is arranged, and the substrate 3 is arranged in parallel with the N-pole magnetized surface 2a of the bias magnet 2 facing the gear surface. Then, as shown in FIG. 5, the angle of the magnetoresistive elements 4 and 5 so that the magnetic resistance elements 4 and 5 with respect to N-pole magnetized surface parallel component vector B _X in the magnetic vector B is substantially 45 °, respectively They are arranged at approximately 90 °.

Here, the principle of magnetism detection will be described. The magnetism detected by the magnetoresistive elements 4 and 5 in this embodiment is the N-pole magnetized surface parallel component vector B _X in the magnetic vector B.
It is. If no gear 7 opposed to the N-pole magnetized surface 2a of the bias magnet 2, N-pole magnetized surface parallel component vector B _X is the direction W which is shown in FIG. If there is a gear 7, the direction W of the N-pole magnetized surface parallel component vector B _X drawn on the teeth 8 of the gear 7 by the rotation of the gear 7 is varied in the range of W1 to W2, based on the center of the bias magnet 2 deflection angle between the N-pole magnetized surface parallel component vector B _X (direction change of the magnetic vector B _X of the arrangement position of the magnetic resistance elements 4 and 5) becomes [Delta] [theta]. The deflection angle Δθ depends on the distance between the bias magnet 2 and the magnetoresistive elements 4 and 5 and the distance between the magnetoresistive elements 4 and 5 and the gear 7.

Arranged at 90 ° angle (45 ° to W)
The pair of placed magnetoresistive elements 4 and 5 are arranged as shown in FIG.
In addition, the N-pole magnetized surface parallel component vector in the magnetic vector B
Le B _XAnd the resistance changes to opposite phases
do. This resistance change corresponds to the waveform processing installed on the same substrate.
Pallet that has been binarized by the logical circuit 6 and matches the teeth 8 of the gear 7
Output

At this time, it has been confirmed that the resistance change waveform does not have a waveform crack at the distance between the gear 7 and the magnetoresistive elements 4 and 5 in the actual use range. Hereinafter, various experiments were performed, and the results will be described.

As shown in FIG. 7, when the angle in the counterclockwise direction formed by the rotation direction of the gear 7 and the magnetoresistive elements 4 and 5 of the substrate 3 is θ, the magnetoresistance when the angle θ is changed The resistance change rates of the elements 4 and 5 were measured. The measurement result,
This is shown in FIGS. As the measurement conditions, as shown in FIG. 9, a rare-earth bias magnet was used, the diameter was 7 mm, the thickness was 4 mm, and the bias magnet 2 was 0.5 mm away from the outer peripheral surface of the bias magnet 2. The magnetoresistive elements 4 and 5 are arranged at the positions. FIG. 10 shows the measurement results when the diameter of the gear 7 is 75 mm, the number of teeth 8 of the gear 7 is “48”, and the thickness of the gear 7 is 10 mm. FIG.
The gear 7 has a diameter of 85 mm and the number of teeth 8 of the gear 7 is "4".
8 "shows the measurement results when the thickness of the gear 7 was 3 mm. 10 and 11, as shown in FIG. 1, the distance L between the magnetoresistive elements 4, 5 and the gear 7 is set to 0.5.
The experimental results are shown with the values changed to mm, 1.0 mm, and 1.5 mm.

From FIGS. 10 and 11, θ = 0 to 360 °
If the angle is other than 0, 180 ° and 360 °, the resistance change rate can be obtained. When the detection limit of the waveform processing circuit 6 is about 0.2% in terms of the resistance change rate, about 30 ° <θ <150
It has been found that the resistance change rate required for gear detection can be obtained at ° and about 210 ° <θ <330 °. Further, the maximum values of the rate of change in resistance are θ = 90 and 270 °.
It was confirmed that it was. That is, as shown in FIG.
If θ = 90 °, the maximum resistance change rate can be obtained.

As described above, considering the mounting error of the air gap (the distance L between the magnetoresistive elements 4, 5 and the gear 7) at the time of packaging and assembling, about 30 ° <θ <150.
° or about 210 ° <θ <330 °, the support plate 1 (the magnetoresistive elements 4 and 5) should be arranged with respect to the gear 7.

Therefore, in FIG. 2, the arrangement positions of the magnetoresistive elements 4 and 5 are perpendicular to the gear rotation direction (θ = 90 °), but 30 ° <θ <150 ° or 210 ° <
It may be performed in the range of θ <330 °.

Next, as shown in FIG. 12, N-pole magnetized surface parallel component vector B _X and N-pole magnetized surface perpendicular component at the position P2 spaced 1.2mm from the N-pole magnetized surface of the bias magnet 2 FIG. 14 shows the measurement result of the vector _BY . Here, FIG.
As shown in the figure, the outer diameter of the bias magnet 2 is 7 mm,
The one having a thickness of 4 mm is used. Then, the center of the bias magnet 2 as a reference position, the radial distance from the center of the bias magnet 2 the horizontal axis of FIG. 14, N-pole magnetized surface force and N-pole magnetized surface perpendicular component of the parallel component vector B _X The vertical axis represents the magnetic force of the vector _BY .

As shown in FIG. 14, the intensity of the N-pole magnetized surface parallel component vector B _X is “0” at the center of the bias magnet 2 and is weakest, and becomes stronger as the distance from the center increases, and becomes maximum at the outer peripheral surface of the bias magnet 2. The value gradually decreases as the distance from the outer peripheral surface of the bias magnet 2 increases. Then, N-pole magnetized surface of the magnetic force of the parallel component vector B _X is less than 100 gauss ± is, ± from the center of the bias magnet 2 0.25 m
m. In other words, if it is out of the range of ± 0.25 mm from the center of the bias magnet 2, ± 10
The magnetic force becomes 0 gauss or more.

On the other hand, the magnetic force of the N-pole magnetized surface perpendicular component vector _BY has its maximum value at the center of the bias magnet 2 and becomes weaker as the distance from the center increases. When the distance from the center of the bias magnet 2 is +5.0 mm or more, the value becomes smaller than +100 Gauss.

Therefore, the N-pole magnetized surface parallel component vector B _X
And the N-pole magnetized surface vertical component vector _BY both become 100 gauss or more, and the magnetoresistive elements 4 and 5 become saturated magnetic field strength or more. 25mm or more and bias magnet 2
Needs to be within 1.5 mm from the outer peripheral surface of.

Further, in FIG. 15, the outer peripheral surface of the bias magnet 2 is used as a reference position as shown in FIG. 13, the diameter of the gear 7 is 85 mm, the number of teeth 8 of the gear 7 is "48", and θ = 0. In this case, the distance (air gap) from the N-pole magnetized surface of the bias magnet 2 is plotted on the horizontal axis, the rate of change in resistance is plotted on the vertical axis, and the distances of the magnetoresistive elements 4 and 5 from the reference position are changed in the radial direction. 2 shows the measurement results.

FIG. 15 shows that the mounting positions of the magnetoresistive elements 4 and 5 are near the outer peripheral surface of the bias magnet 2 (+0.5
mm to -1.5 mm), the necessary resistance change rate can be obtained sufficiently, and it has been found that the allowable range of attachment is wide.

Accordingly, in FIG. 2, the positions of the magnetoresistive elements 4 and 5 are set in the range of 0.25 to 5 mm from the center of the bias magnet 2 (7 mm in diameter), but are 3.5 mm from the center of the bias magnet 2. May be defined near the outer peripheral surface of the bias magnet 2. In this case, a required resistance change rate can be obtained even if the position is slightly shifted.

FIGS. 16 and 17 show the N-pole magnetized surface parallel component vector B when various bias magnets are used.
_X (FIG. 16) and N-pole magnetized surface perpendicular component vector B
17 shows the measurement results of the magnetic force of _Y (FIG. 17). Note that the measurement conditions are the same as the conditions for obtaining the measurement results in FIG.
The horizontal axis in FIGS. 16 and 17 indicates the distance from the center of the bias magnet.

As described above, according to this embodiment, the magnetoresistive elements 4 and 5 are arranged in parallel with the N-pole magnetized surface of the bias magnet 2 and are arranged on the N-pole magnetized surface of the bias magnet 2 in the bias magnetic field. The magnetic vectors BX are arranged in parallel with each other and inclined at a predetermined angle (approximately 90 degrees) with respect to the magnetic vector BX toward the outer peripheral side to detect a change in the magnetic vector BX. Therefore, when the substrate 3 is arranged perpendicular to the N-pole magnetized surface of the bias magnet 2, the sensor is structurally large in the direction perpendicular to the magnetized surface. Since the magnet 2 is arranged parallel to the N-pole magnetized surface, the size can be reduced. In other words, by arranging the substrate 3 parallel to the N-pole magnetized surface, the substrate 3 can be structurally smaller in the direction perpendicular to the magnetized surface than when the substrate 3 is arranged perpendicular to the N-pole magnetized surface. . In the conventional apparatus shown in FIG. 20 , the substrate 20 is fixed to the magnetized surface 23a of the bias magnet 23.
However, in this embodiment, the bias magnet 2, the support plate 1, and the substrate 3 are arranged in parallel with each other, so that the bias magnet 2, the support plate 1, and the substrate 3 can be easily held with an adhesive or the like, and the assembly can be easily performed with high accuracy. Can also be better.

[0040] Further, a predetermined angle (approximately 90 with respect to the magnetic vector B _X toward the magneto-resistive elements 4 and 5 to the parallel and the outer peripheral side of the N-pole magnetized surface bias magnet 2 in the bias magnetic field
Degree) The arrangement is inclined so that the resistance change waveform is prevented from being broken. In particular, when the magnetic resistance elements 4 and 5
_Since it is arranged at an angle of about 45 degrees with respect to _X , the rate of change of resistance shows the maximum value with respect to the deflection of the vector, and the rate of change of resistance can be increased.

Further, since the magnetoresistive elements 4 and 5 are arranged at positions rotated by 30 to 150 degrees or 210 to 330 degrees with respect to the rotation direction of the gear 7, the rate of change in resistance increases, and the rate of change in resistance is ensured. can do.

Further, since the magnetoresistive elements 4 and 5 are disposed at positions rotated by 90 degrees or 270 degrees with respect to the rotation direction of the gear 7, the resistance change rate is further increased. Further, as the arrangement position of the magnetic resistance elements 4 and 5, separated by the required vector B _X from the center of the bias magnet 2 can be obtained, and too far away as required vector B _Y from the outer periphery of the bias magnet 2 can be obtained That is, the range was set to a range that was not more than 0.25 mm from the center of the bias magnet 2 and not more than 1.5 mm from the outer peripheral surface. Therefore, the magnetic field intensity is equal to or higher than the saturation magnetic field intensity of the magnetoresistive elements 4 and 5 (B _X and B _Y are equal to or more than 100 Gauss), and the magnetic vector B _X due to the rotation of the gear 7
Is obtained.

In particular, by arranging the magnetoresistive elements 4 and 5 near the outer peripheral surface of the bias magnet 2, a sufficient rate of change in resistance can be obtained even if there is a slight displacement during mounting.
Further, as shown in FIG. 5, since the two magnetoresistive elements 4 and 5 are arranged close to a predetermined magnetic vector to detect a change in the predetermined magnetic vector, the change in the magnetic vector is stabilized. And when the magnetoresistive element is formed on one substrate, the substrate area can be reduced.

Another embodiment of the present invention will be described below. In the above embodiment, as shown in FIG. 5, the magnetoresistive elements 4 and 5 are arranged so as to extend in a direction of approximately plus or minus 45 ° with respect to the direction (W) of the magnetic vector BX. For example, as shown in FIG. 18, the magnetoresistive elements 4 and 5 are arranged so as to extend in the direction of plus or minus 60 ° with respect to the direction (W) of the magnetic vector BX, or as shown in FIG. The magnetoresistive elements 4 and 5 may be arranged to extend in the direction of plus or minus 135 ° with respect to the direction (W) of the magnetic vector BX . As shown in FIG. 19, arranging the magnetoresistive elements 4 and 5 so as to extend in the direction of plus or minus 135 ° with respect to the direction (W) of the magnetic vector BX means that the magnetic vector BX and the magnetoresistive element This means that the angle formed between the magnetic resistance elements 4 and 5 is 45 °, which means that the magnetoresistive elements 4 and 5 are arranged at an angle of 45 degrees with respect to the magnetic vector BX.

That is, the present invention relates to Japanese Patent Application Laid-Open No. 3-195970.
No. 6,098,067, which applied a concept equivalent to that of the magnetic detection device shown in Japanese Patent Publication No. When the detection signal obtained by the above is binarized by the waveform processing circuit 6, the waveform break phenomenon that the output pulse is doubled when the air gap between the object to be detected and the magnetic detection element is narrowed is prevented. It is made possible. Therefore, in the above embodiment, the angle between the magnetoresistive elements 4 and 5 and the direction of the magnetic vector B _X (the same radial direction) does not have to be 45 °. What is necessary is just to arrange the magnetoresistive elements 4 and 5 so that the angle formed may differ. However, as is also the above publication, if the swing range magnetic vector B _X is from W1 W2 about the direction W as shown in FIG. 5, when the angle is 45 ° (or 135 °),
Since the rate of change in resistance of the magnetoresistive element is the largest, it is best to arrange it at 45 °. Further, the magnetoresistive elements 4 and 5
Is 90 °, the directions of the resistance changes of the two magnetoresistive elements are in opposite phases, and the output voltage can be maximized.

In the above-described embodiment, the magnetic detection is performed by using the magnetic vector B _X directed to the outer peripheral side of the bias magnet 2 with the N-pole magnetized surface of the bias magnet 2 facing the gear 1.
The S-pole magnetized surface of the bias magnet 2 may be opposed to the detection target (gear 1), and the magnetic detection may be performed using a magnetic vector from the outer peripheral side of the bias magnet 2 toward the center of the magnetized surface.
That is, the magnetoresistive elements 4 and 5 are arranged in parallel to the magnetized surface of the bias magnet 2, and have a magnetic vector parallel to the magnetized surface of the bias magnet facing the detection target and moving inward from the outer peripheral side. The magnetic vector may be arranged to be inclined at a predetermined angle to detect a change in the magnetic vector.

In the above embodiment, the bias magnet is
Although a cylindrical shape is used, the bias magnet may have another shape, as long as a magnetic vector is generated from the center of the magnet to the outer peripheral side.

[0048]

As described above in detail, according to the first aspect of the present invention, it is possible to reduce the size and to prevent the resistance change waveform from being broken.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in (1), the rate of change in resistance can be increased. According to the invention set forth in claim 3, claim 1 is provided.
In addition to the effects of the invention described in (1), the rate of change in resistance can be increased.

According to the fourth aspect of the present invention, the first aspect is provided.
In addition to the effects of the invention described in any one of Items 3 to 3, the resistance change rate can be further increased. According to the fifth aspect, in addition to the effects of the first aspect, a sufficient rate of change in resistance can be obtained even if the installation position of the magnetoresistive element is slightly shifted. According to the invention of claim 6
Thus, a better detection method can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a magnetic rotation detecting device according to an embodiment.

FIG. 2 is a view taken in the direction of the arrow A in FIG. 1;

FIG. 3 is a side view showing magnetic lines of force of a bias magnet.

FIG. 4 is a view taken in the direction of arrow B in FIG. 3;

FIG. 5 is a plan view of a substrate.

FIG. 6 is a waveform chart for explaining the operation.

FIG. 7 is an explanatory diagram for explaining an arrangement relationship between a gear and a magnetoresistive element.

FIG. 8 is an explanatory diagram for explaining an arrangement relationship between a gear and a magnetoresistive element.

FIG. 9 is an arrangement diagram showing an arrangement of a bias magnet and a magnetoresistive element.

FIG. 10 is a graph showing a measurement result of a resistance change rate with respect to an element arrangement angle θ.

FIG. 11 is a graph showing a measurement result of a resistance change rate with respect to an element arrangement angle θ.

FIG. 12 is a side view of a bias magnet.

FIG. 13 is a side view of the bias magnet.

FIG. 14 is a graph showing a measurement result of a magnetic force with respect to a distance from a center of a magnet.

FIG. 15 is a graph showing a measurement result of a resistance change rate with respect to an air gap.

Figure 16 is a graph showing the measurement results of B _X force versus distance from the magnet center.

FIG. 17 is a graph showing a measurement result of a _BY magnetic force with respect to a distance from a magnet center.

FIG. 18 is a plan view of another example of a substrate.

FIG. 19 is a plan view of another example of a substrate.

FIG. 20 is a plan view of a conventional rotation sensor.

[Explanation of symbols]

2 ... bias magnet, 3 ... substrate, 4, 5 ... magnetoresistive element,
7: Gears to be detected

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuaki Makino 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Denso Co., Ltd. (56) References JP-A-3-48720 (JP, A) JP-A-7- 4988 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01P 3/488 G01D 5/245

Claims (6)

(57) [Claims] 1. A bias magnet having a magnetized surface facing a detection target having a magnetic material and generating a bias magnetic field toward the detection target; and a magnetoresistive element disposed in the bias magnetic field. A magnetic detection device configured to cause a change in resistance due to a change in a bias magnetic field from the bias magnet to the object to be detected accompanying the movement of the object to be detected in the magnetoresistive element; Along with being arranged parallel to the magnetized surface of the bias magnet, the magnetic field parallel to the magnetized surface of the bias magnet in the bias magnetic field and with respect to the magnetic vector heading toward the outer peripheral side or the magnetic vector heading inward from the outer peripheral side. predetermined angle inclined symmetrically disposed, further
Are arranged at right angles to the rotation direction of the detection target,
A magnetic detection device, wherein a change in the magnetic vector is detected. 2. The magnetic detecting device according to claim 1, wherein the magnetoresistive element is disposed at an angle of about 45 degrees with respect to the magnetic vector. 3. The magnetic detection device according to claim 1, wherein the magnetoresistive element is arranged at a position rotated by 30 to 150 degrees or 210 to 330 degrees with respect to the movement direction of the detection target. . 4. The magnetic detection device according to claim 1, wherein the magnetoresistive element is arranged at a position rotated by 90 degrees or 270 degrees with respect to the direction of movement of the detection target. apparatus. 5. The magnetic detection device according to claim 1, wherein the magnetoresistive element is arranged near an outer peripheral surface of the bias magnet. 6. A bias magnet having a magnetized surface facing a detection target having a magnetic material and generating a bias magnetic field toward the detection target, and a magnetoresistive element disposed in the bias magnetic field, A magneto-resistive element is arranged in parallel with the magnetized surface of the bias magnet, and is parallel to the magnetized surface of the bias magnet in the bias magnetic field, and a magnetic vector directed to the outer peripheral side or inward from the outer peripheral side. It is arranged symmetrically at a predetermined angle with respect to the heading magnetic vector, and
Are arranged at right angles to the rotation direction of the detection target,
Detecting a change in the bias magnetic field from the bias magnet to the object to be detected due to the movement of the object to be detected by the magnetoresistive element; .