JPH0943259A - Rotor to be detected for magnetic sensor, manufacture thereof and rotation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor to be detected for a magnetic sensor capable of suitably giving magnetic vector change to a magnetoresistive element to be applied with a bias magnetic field with a low-cost simpler structure. SOLUTION: The magnetic sensor 3 has a magnetoresistive element MRE applied by a bias magnetic field from behind, and detects the magnetic vector change due to the rotation of a rotor 2 to be detected by the element, and extracts the rotation information of a rotary shaft 1. The rotor 2 to be detected comprises a hole to be engaged with the shaft 1 and rectangular teeth radially protruding at a predetermined interval from the outer periphery of a circle at the hole as a center in such a manner that the rotor is punched from a magnetic material plate and the teeth are further bent perpendicularly from its root to form the part 21 to be detected of the rotor 2. In the environment applied by the bias magnetic field, the magnetic vector to be applied to the element MRE is vibrated by the passage of the part 21 to be detected due to the rotation of the rotor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a device for detecting vehicle speed in a vehicle, engine rotation detection, and various rotation detection in general machinery, which is mounted on a rotation shaft to be detected as a detection target by a magnetic sensor. To a detected object rotor for a magnetic sensor, a method of manufacturing the same, and a rotation detection device using the detected object rotor.

[0002]

2. Description of the Related Art Conventionally, in a device for detecting rotation using a magnetic sensor, a change in the resistance value of a magnetoresistive element as shown in FIG. The rotation is detected.

That is, when a current is applied to the magnetoresistive element MRE arranged on an appropriate insulating substrate in the manner shown in FIG. 10A, the strength of the magnetic field Bx parallel to the current direction is increased. In the case of decreasing, the resistance value of the magnetoresistive element MRE increases by about 0.3%, and in the case of increasing the strength of the magnetic field By perpendicular to the current direction, the resistance value is 4.0. % Decrease. On the other hand, the magnetic field B perpendicular to the substrate
Even if z is applied, the resistance value of the magnetoresistive element MRE does not change. The relationship between the magnetic field strength (magnetic flux density) and the resistance change rate is summarized as shown in FIG.

Taking the example of the type of rotor using a gear made by sintering a magnetic material as an example of the rotor to be detected, a magnetic gear (rotor) based on these characteristics of the magnetoresistive element will be described below. The basic structure of the magnetic sensor for detecting rotation will be described.

First, the magnetoresistive element MR is arranged, for example, as shown in FIG. 11 using the magnetic field whose resistance value greatly changes, that is, so as to be parallel to each tooth of the gear G.
The so-called "parallel arrangement" in which E is arranged will be described.
In FIG. 11, reference numeral BM indicates a bias magnet that applies a bias magnetic field from the tooth direction of the gear G made of a magnetic material.

As shown in FIG. 11, by arranging the magnetoresistive elements MRE in parallel, the same magnetoresistive element MR according to the angle transition of the magnetic vector accompanying the rotation of the gear G is obtained.
The resistance change rate of E is in the form shown in FIG.

That is, the deflection angle of the magnetic vector when there is no misalignment of the magnetoresistive element MRE changes in the region shown as "deflection angle 1" in FIG. The resistance value change waveform of
As shown in (b), a large change comes to be exhibited.
At this time, the center of the bias magnet BM is displaced from the center of the magnetoresistive element MRE in the mode shown in FIG. 11 in order to utilize the steep slope portion of the resistance value change rate characteristic.

On the other hand, when the mounting deviation of the magnetoresistive element MRE becomes "+1 mm", the deflection angle of the magnetic vector becomes as shown in FIG.
2 (a) is moved to the area shown as "deflection angle 2". Therefore, the change in the resistance value of the magnetoresistive element MRE is as shown in FIG.
It becomes extremely reduced as shown in (c).

On the contrary, when the mounting deviation of the magnetoresistive element MRE becomes "-0.4 mm", the deflection angle of the magnetic vector moves to a region shown as "deflection angle 3" in FIG. 12 (a). In this case, when the magnetic vector swings to the maximum (22 °), the resistance value once increased decreases beyond the peak of the same characteristic waveform, and so-called “waveform cracking” as shown in FIG. Will occur. That is, in this case, twice as many pulses are output as compared with the case where there is no mounting deviation, which causes a great inconvenience in practical use.

In such a sensor structure in which the magnetic resistance elements MRE are arranged in parallel, the same magnetic resistance element MRE is used.
Even if the air gap between the magnetically sensitive surface and the crest of the gear G is small, the magnetic vector fluctuates too much, causing the above "waveform crack"
Is more likely to occur.

Therefore, conventionally, the magnetoresistive element MRE is inclined by 45 ° with respect to the deflection angle of the magnetic vector so that the resistance value of the magnetoresistive element MRE is changed by the combined magnetic field of the magnetic field Bx and the magnetic field By. A sensor structure that is arranged perpendicular to the magnet surface is also under study.

Such a sensor structure is so-called "vertical arrangement" in contrast to the above-mentioned "parallel arrangement", and basically has a structure shown in FIG. That is, in this vertical arrangement, as shown in FIG. 13, the first and second magnetoresistive elements MRE are arranged on the substrate arranged perpendicular to the bias magnet BM with respect to the deflection angle of the magnetic vector. 45 °
It is arranged at an angle. The rate of change in resistance value of the magnetoresistive elements MRE according to the angle transition of the magnetic vector accompanying the rotation of the gear G is in the form shown in FIG.

Incidentally, in this case, if the mounting deviation of the magnetoresistive element MRE is "-1 mm", its resistance value changes in the area shown as "deflection angle 1" in FIG. If the mounting deviation of the MRE is "+1 mm",
The resistance value changes in a region shown as "deflection angle 2" in FIG. In any of these cases, since the deflection angle of the magnetic vector does not exceed the peak of the resistance value change rate waveform, the “waveform crack” occurs as shown in FIG. 14B or 14C. There is no concern.

In this case, however, FIGS. 14 (b) and 14 (c)
As will be shown in addition, the offset of the resistance value is generated due to the mounting deviation of the magnetoresistive elements, and a circuit for processing the output thereof also needs a highly accurate circuit capable of absorbing the offset. . Further, in this case, the sensitivity of the magnetoresistive element is lower than that of the "parallel arrangement" as shown in FIG.

As described above, the magnetic sensor used in the device for detecting the rotation is basically a magnetoresistive element MRE.
There are a "parallel arrangement" structure and a "vertical arrangement" structure, each of which has advantages and disadvantages as described above. In recent years, any of these structures has been put into practical use by taking advantage of its advantages.

By the way, in the above description, for the sake of convenience, a so-called magnetic gear type of using a gear made by sintering a magnetic material as the rotor to be detected (for example, Japanese Patent Laid-Open No. 6-1).
The structure of the magnetic sensor has been described with reference to Japanese Patent No. 74490). However, as such a magnetic sensor, the rotor to be detected itself attached to the rotary shaft is magnetized to have a plurality of magnetic poles. There is also a so-called magnetized rotor type (see, for example, JP-A-6-241829).

[0017]

Whether the structure in which the magnetoresistive elements are "parallelly arranged" or "vertically arranged" is used, such a magnetic sensor is the rotor to be detected as described above. The rotation of the magnetic body gear or the magnetized rotor is detected based on the presence or absence of a change in the magnetic vector associated with the rotation of the rotor.

However, the above magnetized rotor type magnetic sensor has a disadvantage that the manufacturing process of the rotor requires not only a magnet material but also a step for carrying out the above magnetizing, so that the manufacturing cost is naturally high. is there.

On the other hand, the magnetic gear type magnetic sensor uses a relatively low-cost sintered material and does not require a magnetizing step, so that the magnetic sensor of the magnetic rotor type is used. Although the manufacturing cost can be reduced, the manufacturing cost and the manufacturing cost cannot be neglected in view of the equipment and the processing time required for the sintering process.

The present invention has been made in view of the above circumstances, has a simpler structure which is inexpensive in cost, and can suitably change the magnetic vector with respect to the magnetoresistive element to which the bias magnetic field is applied. It is an object of the present invention to provide a detected object rotor for a magnetic sensor that can be applied.

Another object of the present invention is to provide a suitable method for manufacturing a rotor for a magnetic sensor for a magnetic sensor having such a simple structure. It is another object of the present invention to provide a rotation detecting device that can perform rotation detection with a simple and sufficiently high precision by using such a detected object rotor for a magnetic sensor.

[0022]

In order to achieve such an object, in the invention described in claim 1, the rotating shaft to be detected is mounted on the rotating shaft and the rotating shaft is applied to the magnetoresistive element to which a bias magnetic field is applied from behind. As a detection object rotor for a magnetic sensor that imparts a magnetic vector change corresponding to the rotation of a magnetic body, a magnetic body that imparts a magnetic vector change corresponding to the rotation of the rotation axis to the magnetoresistive element is perpendicular to the rotation axis. In the cross-section, the detected portion has a structure that is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor.

Further, in the invention of claim 2, in the structure of the invention of claim 1, the detection part is a projection provided in a strip shape around a magnetic plate mounted on the rotary shaft. The part is configured as being bent at a right angle.

According to the invention of claim 3, in the structure of the invention of claim 1, the detected magnetic material is a cylindrical magnetic material having windows arranged periodically in the circumferential direction of the outer peripheral surface. And is supported by an appropriate supporting member mounted on the rotary shaft.

In the invention according to claim 4, in the structure of the invention according to claim 1, the substantially U-shaped wire made of a magnetic material is provided around the axis of the rotary shaft in the detected portion. It is configured to be arranged radially.

According to a fifth aspect of the present invention, in the configuration of the first aspect of the invention, the detected portion is provided on the outer peripheral surface of a cylindrical non-magnetic body rotor mounted on the rotating shaft. The magnetic wire is periodically embedded along the direction and parallel to the rotation axis.

According to a sixth aspect of the present invention, in the structure of the first aspect of the invention, the detected portion is provided along the outer periphery of the disc-shaped non-magnetic rotor mounted on the rotating shaft. In addition, the magnetic pins are periodically arranged parallel to the rotation axis.

According to a seventh aspect of the present invention, in the configuration of the first aspect of the invention, the detected portion is circumferentially formed on an outer peripheral surface of a cylindrical non-magnetic rotor mounted on the rotating shaft. It is constituted by magnetic material rivets which are periodically arranged along.

Further, according to the present invention, there is provided a hole fitted from the magnetic plate to the rotary shaft, and strip-shaped teeth radially protruding from the outer periphery of a circle centered on the hole at predetermined intervals. The detected body rotor for a magnetic sensor is manufactured by a step of punching a disk and a step of bending the strip-shaped teeth of the punched magnetic material plate disk at right angles at their roots.

Further, in the invention according to claim 9, a step of holding a large number of wire rods or pins made of a magnetic material in parallel and at predetermined intervals along the inner surface of the mold corresponding to the rotor shape, and nonmagnetic to the mold. The step of pouring a material to fix the held magnetic material wire rod or pin is carried out to manufacture the detected object rotor for a magnetic sensor.

According to the tenth aspect of the invention, a step of holding a large number of wire rods made of a magnetic material in parallel and at a predetermined interval along the inner surface of the mold corresponding to the rotor shape, and a non-magnetic material in the mold. The detected body for a magnetic sensor, comprising: a step of pouring and fixing the held magnetic wire; and a step of slicing the nonmagnetic material solid in which the magnetic wire is fixed and embedded according to a desired rotor thickness. Manufacture the rotor.

According to the eleventh aspect of the present invention, a step of holding a large number of studs made of a magnetic material at predetermined intervals along the inner surface of the mold corresponding to the rotor shape, and pouring a non-magnetic material into the mold. The detected object rotor for a magnetic sensor is manufactured, including the step of fixing the held magnetic material tack.

According to the twelfth aspect of the present invention, the structure is such that it is attached to the rotary shaft to be detected, and the magnetic substance is present in a dot shape with a predetermined arrangement period on the outer periphery in a cross section perpendicular to the rotary shaft. A detected object rotor having a detected part, a bias magnet for generating a bias magnetic field toward the detected part of the detected object rotor, and the detected object disposed in the generated bias magnetic field. A magnetoresistive element for converting a change in magnetic vector caused by rotation of a body rotor into a change in electric signal, and a signal processing circuit for processing the converted electric signal as required to obtain rotation information of the rotary shaft to be detected. And a rotation detection device.

According to the thirteenth aspect of the invention, in the configuration of the twelfth aspect of the invention, the rotor to be detected is provided in a strip shape around the magnetic plate attached to the rotary shaft. It is configured to have a detected portion in which the protruding portion is bent at a right angle.

According to a fourteenth aspect of the present invention, in the configuration of the present invention according to the twelfth aspect, the rotor to be detected is a cylindrical magnetic body having window holes periodically arranged in the circumferential direction of the outer peripheral surface. The material is provided with a detected portion supported by an appropriate supporting member mounted on the rotating shaft.

According to a fifteenth aspect of the present invention, in the structure according to the twelfth aspect of the present invention, the substantially U-shaped wire rod made of a magnetic material is provided around the axis of the rotary shaft in the detected object rotor. In addition, it is configured to include a detected portion radially arranged.

According to a sixteenth aspect of the present invention, in the configuration of the present invention according to the twelfth aspect, the detected body rotor is provided on the outer peripheral surface of a cylindrical non-magnetic body rotor mounted on the rotating shaft. It is configured to include a detected part made of a magnetic wire that is periodically embedded along the circumferential direction and in parallel with the rotation axis.

According to a seventeenth aspect of the present invention, in the configuration of the present invention according to the twelfth aspect, the rotor to be detected is provided on the outer periphery of the disc-shaped non-magnetic rotor mounted on the rotary shaft. The detection unit is composed of magnetic pins that are periodically arranged along the rotation axis.

According to the eighteenth aspect of the present invention, in the configuration of the present invention according to the twelfth aspect, the rotor to be detected is provided on the outer peripheral surface of a cylindrical non-magnetic rotor mounted on the rotary shaft. The detection unit is composed of magnetic studs that are periodically arranged along the direction.

According to the nineteenth aspect of the invention, in the configuration of the invention according to any of the twelfth to eighteenth aspects, the angle formed between the magnetoresistive element and the magnetic force line emitted from the bias magnet is 45 degrees. The bias magnet is composed of two elements arranged at right angles and perpendicular to the magnetized surface of the bias magnet.

The operation of each of these inventions is as follows. As the detected object rotor for the magnetic sensor according to the invention of claim 1, the magnetic body that imparts a magnetic vector change corresponding to the rotation of the rotation axis to the magnetoresistive element is perpendicular to the rotation axis. In the cross section, the detected portion has a structure that is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor. With such a configuration, in the bias magnetic field applied from the back of the magnetoresistive element, the magnetic vector thereof changes (is swung) only based on the passage of the magnetic substance existing in the point form. . Also, regarding the relationship between the detected object rotor and the magnetic resistance element, it is sufficient that the detected object rotor can impart such a magnetic vector change to the magnetic resistance element as the detection object rotor rotates.

Therefore, according to the same construction of the first aspect of the invention, in the cross section perpendicular to the rotation axis, the magnetic substance is present in a dot-like manner at the outer circumference of the rotor in a predetermined arrangement period, which is a very simple construction. However, a necessary and sufficient function for imparting a magnetic vector change to the magnetoresistive element can be realized.

According to the second aspect of the invention,
The above-mentioned detected part includes: A strip-shaped protruding portion that is bent at a right angle around a magnetic plate mounted on the rotating shaft. In the case of the above structure, the structure of the detected object rotor for the magnetic sensor becomes particularly simple, and the manufacturing cost can be kept extremely low. As described above, even with such a simple configuration, the necessary and sufficient function for imparting the magnetic vector change to the magnetoresistive element can be realized.

According to the invention of claim 3,
The detected part is made of: a cylindrical magnetic material having window holes periodically arranged in the circumferential direction of the outer peripheral surface, which is supported by an appropriate supporting member mounted on the rotary shaft. In this case, the basic structure is the same as that of the invention described in claim 2, but the detected parts are periodically arranged in the circumferential direction of the outer peripheral surface of the cylindrical magnetic material. Since the window hole is configured as a so-called "window frame", it is more stable in terms of strength.

According to the invention of claim 4,
The detected part includes: a substantially U-shaped wire made of a magnetic material arranged radially around the axis of the rotary shaft. It can also be configured as Even in this case, in the cross section perpendicular to the rotation axis, the magnetic substance has a structure in which the magnetic substance is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor, and as described above, the magnetic vector changes with respect to the magnetic resistance element. Necessary and sufficient functions for granting will be realized. According to the fourth aspect of the present invention, the magnetic wire rod is radially wound around the axial center of a cylindrical (disc-shaped) rotor made of a non-magnetic material such as resin. Things are also included.

In addition to the above-mentioned detected portion, for example, according to the invention as defined in claim 5, the outer peripheral surface of the cylindrical nonmagnetic rotor mounted on the rotating shaft is arranged along the circumferential direction thereof. And a magnetic wire rod that is periodically buried parallel to the rotation axis. Alternatively, claim 6
According to the invention described above, a magnetic pin arranged periodically along the outer periphery of the disk-shaped non-magnetic rotor mounted on the rotary shaft and parallel to the rotary shaft. Alternatively, according to the invention of claim 7, the magnetic non-magnetic rotor is periodically arranged on the outer peripheral surface of the cylindrical non-magnetic rotor mounted on the rotating shaft along the circumferential direction thereof. . And so on.

According to these structures, while the strength of the magnetic sensor rotor for the magnetic sensor and the detected portion thereof is sufficiently secured, the magnetic body is provided on the outer circumference of the rotor in the cross section perpendicular to the rotation axis. A point-like structure can be realized with a predetermined arrangement period. And for this reason,
With these configurations as well, it becomes possible to suitably impart a magnetic vector change to the magnetoresistive element.

On the other hand, as a method of manufacturing such a rotor for a magnetic sensor to be detected, according to the invention as defined in claim 8, (A1) a hole fitted to the rotary shaft from the magnetic plate is centered on the same hole. A step of punching out a disc having strip-shaped teeth radially protruding from the outer periphery of the circle at predetermined intervals. (A2) A step of bending the strip-shaped teeth of the punched magnetic material plate disk at a right angle at their roots. According to the method including the above steps, the magnetic substance sensor rotor for a magnetic sensor according to the second aspect of the present invention,
Through the pressing process in the above-described mode, it becomes possible to manufacture extremely easily and highly accurately. Further, according to such a manufacturing method, mass production of the rotor to be detected is easy.

Further, as a method for manufacturing a rotor for a magnetic sensor to be detected, according to the invention of claim 9, (B1) a large number of wire rods made of a magnetic material along the inner surface of the mold corresponding to the rotor shape. Alternatively, a step of holding the pins in parallel and at a predetermined interval. (B2) A step of pouring a non-magnetic material into the mold to fix the held magnetic wire or pin. According to the method including each step, the above-mentioned claim 5 or 6
The detected object rotor for a magnetic sensor according to the described invention can be manufactured with high accuracy and high efficiency. In this case, as the non-magnetic material to be poured into the mold, there is resin or the like.

Further, in addition to the detected object rotor for a magnetic sensor according to the invention described in claim 5, as in the invention described in claim 10, (C1) along the inner surface of the mold corresponding to the rotor shape. A step of holding a large number of wire rods made of a magnetic material in parallel and at predetermined intervals. (C2) A step of pouring a non-magnetic material into the mold to fix the held magnetic wire. (C3) A step of slicing the non-magnetic material solid in which the magnetic material wire is fixedly embedded, according to a desired rotor thickness. It can also be manufactured through each process such as. That is, a long one is prepared as the die and the magnetic wire rod, and the long cylindrical rotor base obtained through the steps (C1) and (C2) is sliced through the step (C3). Therefore, mass production of the detected object rotor for a magnetic sensor according to the present invention can be expected.

Further, as a method of manufacturing a rotor to be detected for a magnetic sensor, according to the invention of claim 11, (D1) a large number of tacks made of a magnetic material are provided along the inner surface of the mold corresponding to the rotor shape. To hold at a predetermined interval. (D2) A step of pouring a non-magnetic material into the mold to fix the held magnetic material tack. According to the method including the steps described above, it becomes possible to manufacture the detected object rotor for a magnetic sensor according to the invention described in claim 7 with high accuracy and high efficiency. Also in this case, a resin or the like is used as the non-magnetic material that is poured into the mold.

On the other hand, as the rotation detecting device,
According to the invention as set forth in claim 2, (a) a structure having a structure in which a magnetic substance is present in a dot shape with a predetermined arrangement period on its outer periphery in a cross section perpendicular to the rotation shaft to be detected. An object rotor having a detection unit. (B) A bias magnet that generates a bias magnetic field toward the detected part of the detected object rotor. (C) A magnetoresistive element which is disposed in the generated bias magnetic field and converts a change in magnetic vector due to the rotation of the detected object rotor into a change in electric signal. (D) A signal processing circuit that processes the converted electric signal as required to obtain rotation information of the rotary shaft to be detected. According to the configuration including each element, the magnetic resistance element is appropriately changed with the rotation of the rotor while the detected object rotor having the extremely simple structure is adopted. Become so. That is, also in the signal processing circuit, it is possible to reliably obtain the rotation information about the rotation axis to be detected.

The number or the arrangement period of the detected portions (magnetic bodies) as the above-mentioned detected object rotor is arbitrary according to the desired rotation angle information. (A) The number of detected portions If the value is increased, the deflection angle of the magnetic vector becomes small, and the S / N of the electric signal converted by the magnetoresistive element deteriorates. (B) If the arrangement intervals (intervals) of the detected parts are the same, it is better to narrow the width (the length in the rotation direction) of the magnetic material that constitutes each of the detected parts. Grows. That is, the S / N ratio of the electric signal converted by the magnetoresistive element is improved. Further, the waveform of this electric signal also becomes a waveform that is closer to a sine wave and has less distortion. Since there is also a relationship with the output, it is desirable for practical purposes to optimize such a situation including its shape.

Further, as a concrete form of such a detected object rotor, for example, according to the invention as defined in claim 13, the rectangular protrusions are provided around the magnetic plate mounted on the rotating shaft at right angles. It has a bent detection part. Alternatively, according to the invention of claim 14, the detected portion is formed by supporting a cylindrical magnetic material having window holes periodically arranged in the circumferential direction of the outer peripheral surface by an appropriate supporting member mounted on the rotating shaft. With. Alternatively, according to the invention of claim 15, a substantially U-shaped wire made of a magnetic material is provided radially around the axis of the rotary shaft.
Alternatively, according to the sixteenth aspect of the present invention: A magnetic wire rod is periodically embedded along the circumferential direction of the cylindrical non-magnetic rotor mounted on the rotary shaft along the circumferential direction thereof and in parallel with the rotary shaft. It has a detected part.
Alternatively, according to the invention of claim 17, the detected object is composed of magnetic pins arranged periodically along the outer periphery of the disk-shaped non-magnetic rotor mounted on the rotary shaft and parallel to the rotary shaft. One that has a section. Alternatively, according to the invention of claim 18, wherein the outer peripheral surface of the cylindrical non-magnetic body rotor mounted on the rotating shaft is provided with a detected portion composed of magnetic material studs arranged periodically along the circumferential direction thereof. . And so on.

In particular, according to the thirteenth aspect of the invention, the cost of the rotation detecting device can be kept extremely low. Further, the above claims 16 to
In the invention described in Item 18, it is necessary for the rotation detecting device to impart a magnetic vector change to the magnetoresistive element while sufficiently securing the strength of the detected object rotor and the detected part thereof. A sufficient structure will be realized. Moreover, in the inventions according to claims 16 to 18, since all the parts other than the detected part of the detected object rotor are made of a non-magnetic material such as resin, the passage of the detected part is magnetically performed. The detection accuracy of the rotation detection device for detection is extremely good. The detected object rotors according to the inventions described in claims 13 to 18 correspond to the inventions described in claims 2 to 7, respectively, and these detected objects are used as the rotation detection device. The operations performed based on the rotor are also in accordance with those inventions.

On the other hand, according to the nineteenth aspect of the present invention, in the magnetic resistance element constituting the rotation detecting device, the angles formed by the magnetic lines of force generated from the bias magnet are mutually inclined by 45 degrees, and the bias magnet is the same. It is composed of two elements arranged perpendicular to the magnetized surface. When such a so-called "vertical arrangement" is adopted, although the sensitivity is slightly lowered, a stable sensor output free from the above-mentioned "waveform breakage" can be obtained.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a first embodiment of a magnetic-sensor-detected-body rotor and a rotation detection apparatus using the detected-body rotor according to the present invention.

The rotation detecting device according to the first embodiment, for example, detects vehicle speed and engine rotation in a vehicle,
Further, it is configured as a device for detecting various rotations in a general machine. In particular, in this apparatus, a disc made of a magnetic plate having a simple shape as shown in FIG. 1 is used as the detected object rotor mounted on the rotary shaft to be detected.

First, the structure of the rotor to be detected according to this embodiment will be described with reference to FIG. As shown in FIG. 1, the rotor 2 to be detected is fitted and attached to a rotary shaft 1 to be detected, such as an axle, an engine output shaft, or a rotary shaft of various machines, and is rotated when the rotary shaft 1 rotates. Along with this, for example, it rotates in a manner indicated by an arrow in the drawing.

Further, the detected object rotor 2 is provided with a strip-shaped protruding portion around an appropriate magnetic plate which is fitted and mounted on the rotary shaft 1, and the protruding portion is bent at a right angle. Thus, the detected portion 21 as the rotor 2 is formed. That is, the detected portion 21 is arranged in a predetermined manner on the outer circumference of the rotor in a cross section perpendicular to the rotary shaft 1, more accurately, in a cross section perpendicular to the rotary shaft 1 and facing the sensor portion of the magnetic sensor 3. It has a structure in which magnetic substances are present in a dot shape with a period.

FIG. 2 is a front view of the rotation detecting device (rotating shaft 1).
3 shows the positional relationship between the detected object rotor 2 and the magnetic sensor 3 as viewed from the axial direction). Next, the basic operation of the rotation detecting device will be described with reference to FIG.

As shown in FIG. 2, the magnetic sensor 3 has the above-mentioned "vertically arranged" magnetoresistive element MRE.
The sensor unit 31 is basically configured to include a sensor unit 31 and a bias magnet 32 that applies a bias magnetic field from behind. Therefore, every time the detected portions (magnetic bodies) 21 of the detected body rotor 2 which are arranged in the above-described cycle pass through the bias magnetic field applied from the bias magnet 32, the magnetic vector on the sensor section 31 is changed. Change (deflection)
Occurs, and the change in the magnetic vector is converted into an electric signal by the two magnetoresistive elements MRE forming the sensor unit 31. The converted electric signal is input to the processing circuit 4 shown in FIG. 1 and binarized, and the binarized signal is used as the rotation information of the rotary shaft 1 to be detected, which is not shown in the figure, such as a microcomputer. Will be incorporated into the arithmetic circuit consisting of. Incidentally, the arithmetic circuit calculates the rotation speed of the rotary shaft 1 from the cycle of the binarized signal, and also calculates the rotation angle of the rotary shaft 1 from the number of the binarized signals. .

The specific structure of the “vertically arranged” magnetoresistive element MRE and the magnetoelectric conversion operation by these elements are as described above with reference to FIGS. 13 and 14.

FIG. 3 shows experimental results of the rotation detecting device according to the embodiment using the rotor 2 as the object rotor and the conventional rotation detecting device using the magnetic gear type. The output characteristics are shown for reference.

In FIG. 3, FIG. 3 (a) shows a rotation according to the embodiment in which a rotor having a diameter of 75 mm and 48 detection portions 21 having a width of 1 mm is used as the rotor 2 to be detected. The output characteristic of the detection device (the output of the magnetic sensor 3) is shown.

Further, in FIG. 3B, FIG. 3B shows the output characteristics of a conventional rotation detecting device using a magnetic sintered gear having a diameter of 71 mm and 48 teeth (triangular teeth) as the object rotor ( Magnetic sensor output).

Note that these rotation detecting devices are different in only the rotor of the object to be detected, and the magnetic sensor and other components are all common. These Figure 3
As is clear from comparison between (a) and (b), although the structure of the rotor to be detected is largely different as described above, the output obtained from the magnetic sensor due to the rotation of the rotor has almost the same sine wave characteristics. Has become. In terms of sensitivity, it can be said that the rotation detecting device according to the same embodiment using the detected object rotor 2 is superior. In any case, this experimental result shows that the rotation detecting device according to the embodiment can obtain characteristics comparable to those of the conventional rotation detecting device using the magnetic sintered gear.

In addition, in the rotation detecting device according to the embodiment, the output characteristics are sampled even when the width and the number of the detected parts 21 of the detected object rotor 2 are changed. Are also shown as FIGS. 3 (c) and 3 (d).

As shown in FIG. 3C, when the width of the protrusion as the detected portion 21 is increased to 2 mm, its sensitivity (output level) is slightly lowered, and
The waveform will also be slightly distorted. This is because the fluctuation of the magnetic vector is suppressed during the period corresponding to the width of the detected part 21.

On the other hand, as shown in FIG. 3D, when the number of protrusions as the detected portion 21 is increased to 72, the sensitivity (output level) is greatly lowered. This is because a sufficient pitch of the magnetic vector cannot be obtained because the arrangement pitch of the detected parts 21 is small.

Therefore, practically, it is desirable that the width and the number of the detected portions 21 be optimized in consideration of such a relationship. As described above, in the rotation detecting device according to the embodiment, the rotor having the extremely simple structure as described above is used as the rotor 2 to be detected, but the magnetism is accurately applied to the magnetoresistive element MRE. It becomes possible to add a vector change.

Further, in the same rotation detecting device, as the magnetic sensor 3, the magnetic resistance element MRE which is "vertically arranged" is used.
Since the above is adopted, it is possible to obtain a stable sensor output that does not cause the above-mentioned “waveform crack”.

In the case of the same rotation detecting device, since the rotor 2 to be detected is an extremely inexpensive one obtained by pressing one magnetic plate, the rotation detecting device itself Manufacturing costs will also be significantly reduced.

FIG. 4 shows a manufacturing process of the detected object rotor 2. Next, an example of a method of manufacturing the detected object rotor 2 will be described with reference to FIG.
In this manufacturing method, as shown in FIG. 4 (a), first, as shown in FIG. 4 (a), the holes 22 fitted into the rotary shaft 1 and the strip-like shapes radially protruding from the outer circumference of a circle centered on the hole 22 at predetermined intervals. A disk having teeth 21 'is punched out from a magnetic plate by pressing.

Next, as shown in FIG. 4 (b), the strip-shaped teeth 21 'of the punched disk of the magnetic material plate are bent at a right angle at their roots to form the above-mentioned rotor 2 for the object to be detected. The detected part 21 is formed.

In addition, as for the hole 22, a part 22 'around the hole 22 is punched out as shown in FIG. 4B so that the hole 22 can be easily fitted into the rotary shaft 1.
Note that these bending and punching processes can also be performed simultaneously with the punching or separately through a press machine.

According to the same manufacturing method, as described above, the rotor 2 to be detected can be manufactured extremely easily and highly accurately. Further, according to such a manufacturing method, mass production of the same detected object rotor 2 is easy.

(Second Embodiment) FIG. 5 shows a second embodiment of the magnetic sensor rotor to be detected according to the present invention. Note that, also in this embodiment, the configuration as the rotation detection device is based on that of the first embodiment.

The detected object rotor 5 according to the second embodiment is made of a cylindrical magnetic material having window holes 52 periodically arranged in the circumferential direction of the outer peripheral surface, as shown in FIG. The detected portion 51 as the detected object rotor 5 is formed by the portion corresponding to the “window frame” of the window hole 52. The body portion of the rotor 5 on which the detected portion 51 is formed is integrally supported (bonded, brazed, etc.) by, for example, a support member 53 made of the same material as the axle shaft, It is fitted and attached to the rotary shaft 1 to be detected, such as the engine output shaft or the rotary shaft of various machines. Then, as the rotary shaft 1 rotates, the rotary shaft 1 rotates, for example, in a manner indicated by an arrow in the drawing.

According to such a configuration as the detected object rotor 5 according to the second embodiment, the structure of the detected portion 51 is basically the same as that of the first embodiment, but Since it is configured as the "window frame" of the window holes 52 arranged in the above cycle, the strength becomes more stable.

The detected object rotor 5, like the detected object rotor 2 according to the first embodiment, can be mass-produced by press working, but the support member 53 is used.
It is undeniable that the manufacturing process will be somewhat complicated due to the need for bonding with or brazing.

(Third Embodiment) FIG. 6 shows a third embodiment of the magnetic sensor detected object rotor according to the present invention. Even in this embodiment, the configuration as the rotation detection device is based on that of the first embodiment.

In the detected object rotor 6 according to the third embodiment, as shown in FIG. 6, a substantially U-shaped wire made of a magnetic material such as a piano wire is used as the axis of the rotary shaft 1. It is arranged radially around the center. And
The outer peripheral portion of each of the magnetic wires forms a detected portion 61 as the detected rotor 6.

Even with such a structure of the rotor 6 to be detected, in the cross section perpendicular to the rotating shaft 1, the magnetic substance has a structure in which the magnetic substance is present in a dot shape on the outer circumference of the rotor with a predetermined arrangement period, and as described above, A necessary and sufficient function for imparting a magnetic vector change to the resistance element will be realized.

In the rotor 6 to be detected according to the third embodiment, for example, a cylindrical (disc-shaped) rotor made of a non-magnetic material such as resin is used, and the magnetic wire rod has its axial center. It also includes a configuration that is radially wound around the center.

(Fourth Embodiment) FIG. 7 shows a fourth embodiment of the rotor to be detected for a magnetic sensor according to the present invention. Even in this embodiment, the configuration as the rotation detection device is based on that of the first embodiment.

The detected object rotor 7 according to the fourth embodiment is, as shown in FIG. 7, a columnar non-magnetic material rotor 72 mounted on the rotary shaft 1 and made of, for example, resin.
A magnetic wire rod is periodically embedded in the outer peripheral surface of the magnetic material along the circumferential direction and in parallel with the rotating shaft 1. Then, the magnetic wire rods buried in these cycles form a detected portion 71 as the detected rotor 7.

Even with such a configuration of the detected object rotor 7 according to the fourth embodiment, in the cross section perpendicular to the rotating shaft 1, the magnetic material is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor. The structure is realized, and the necessary and sufficient function for imparting a magnetic vector change to the magnetoresistive element is preferably realized.

Further, according to the detected object rotor 7, only the detected part 71 is made of a magnetic material, and the change in the magnetic vector applied to the magnetoresistive element is also detected. More precise, purely dependent on 7 rotations only.

The object rotor 7 having such a structure can be manufactured by the following procedure, for example. (1) The magnetic wire rods are held in parallel and at predetermined intervals along the inner surface of the mold corresponding to the rotor shape. here,
By using an appropriate jig integrally formed with the mold or detachably attached to the mold, the magnetic wire can be easily and accurately held. (2) A non-magnetic material such as resin is poured into the mold to fix the held magnetic wire. (3) After the magnetic material wire is fixed, the mold and the jig are removed to obtain the detected object rotor 7 of the form shown in FIG.

According to such a manufacturing method, it becomes possible to manufacture the detected object rotor 7 according to the fourth embodiment with high accuracy and high efficiency. In addition, as a method of manufacturing the detected object rotor 7 according to the fourth embodiment, a long one is prepared as the die and the magnetic wire rod, and the steps (1) to (3) are performed. After the long cylindrical rotor substrate is obtained, (4) the obtained rotor substrate is sliced according to the desired rotor thickness. It is also possible to obtain the detected object rotor 7 of the form shown in FIG. In particular, according to such a manufacturing method, mass production of the detected object rotor 7 can be expected.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment of the rotor to be detected for a magnetic sensor according to the present invention. Even in this embodiment, the configuration as the rotation detection device is based on that of the first embodiment.

As shown in FIG. 8, the detected object rotor 8 according to the fifth embodiment has a disk-shaped non-magnetic rotor 82 mounted on the rotary shaft 1 and made of, for example, resin.
The magnetic pins are periodically arranged along the outer periphery of and in parallel with the rotating shaft 1. Then, the detected portion 81 as the detected object rotor 8 is formed by the magnetic pins arranged in these cycles.

Even with such a configuration of the detected object rotor 8 according to the fifth embodiment, in the cross section perpendicular to the rotary shaft 1, the magnetic material is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor. The structure is realized, and a necessary and sufficient function for giving a magnetic vector change to the magnetoresistive element is realized.

Also in the detected object rotor 8,
Only the detected portion 81 is made of a magnetic material, and a highly accurate magnetic vector change that purely depends only on the rotation of the detected rotor 8 is applied to the magnetoresistive element. Will be able to.

The detected object rotor 8 having such a structure is basically manufactured in the same manner as the detected object rotor 7 according to the fourth embodiment described above, for example, by the following procedure. (1) The magnetic pins are held in parallel and at predetermined intervals along the inner surface of the mold corresponding to the rotor shape. Also in this case, the magnetic pin can be easily and accurately held by using an appropriate jig integrally formed with the mold or detachably attached to the mold. (2) A non-magnetic material such as resin is poured into the mold to fix the held magnetic pin. (3) After the magnetic material pins are fixed, the mold and the jig are removed to obtain the detected object rotor 8 shown in FIG.

According to such a manufacturing method, it becomes possible to manufacture the detected object rotor 7 according to the fifth embodiment with high accuracy and high efficiency. In addition, as the method of manufacturing the detected object rotor 8 according to the fifth embodiment, other methods are as follows: Aspect shown in FIG. 8 along the outer periphery of the disk-shaped nonmagnetic rotor 82 made of the above resin or the like. Drive the magnetic pin with. Such a method can also be adopted. When the disk-shaped non-magnetic rotor 82 is formed by a mold or the like, at the same time, a hole or the like is provided in the portion into which the magnetic pin is driven, even if such a manufacturing method is used, it is relatively easy. The object rotor 8 can be obtained.

(Sixth Embodiment) FIG. 9 shows a sixth embodiment of the rotor to be detected for a magnetic sensor according to the present invention. Even in this embodiment, the configuration as the rotation detection device is based on that of the first embodiment.

The detected object rotor 9 according to the sixth embodiment is, as shown in FIG. 9, a columnar non-magnetic material rotor 92 made of, for example, resin mounted on the rotary shaft 1.
Magnetic material studs are periodically arranged along the circumferential direction on the outer peripheral surface of the. Then, the magnetic material studs arranged in a cycle form the detected portion 91 as the detected rotor 9.

Even with such a structure of the rotor for detection 9 according to the sixth embodiment, in the cross section perpendicular to the rotation axis 1, the magnetic material is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor. The structure is realized, and the necessary and sufficient function for imparting a magnetic vector change to the magnetoresistive element is preferably realized.

Also in the detected object rotor 9,
Only the detected portion 91 is made of a magnetic material, and a highly accurate magnetic vector change that purely depends only on the rotation of the detected rotor 9 is applied to the magnetoresistive element. Will be able to.

The object rotor 9 having such a structure is manufactured, for example, by the following procedure. (1) The magnetic tacks are held at predetermined intervals along the inner surface of the mold corresponding to the rotor shape. Here, by using an appropriate jig integrally formed with the mold or detachably formed with the mold, the magnetic tack can be easily and accurately held. (2) A non-magnetic material such as resin is poured into the mold to fix the held magnetic pin. (3) After fixing the magnetic tacks, remove the mold and jig,
The detected object rotor 9 having the configuration shown in FIG. 9 is obtained.

According to such a manufacturing method, it becomes possible to manufacture the detected object rotor 9 according to the sixth embodiment with high accuracy and high efficiency. Further, regarding the detected object rotor 9 according to the sixth embodiment, other manufacturing methods are the same as those of the detected object rotor 8 according to the fifth embodiment described above. The magnetic material studs are driven along the circumferential direction of the outer peripheral surface of the cylindrical non-magnetic rotor 92 made of the same material in the manner shown in FIG. Such a method can also be adopted. Also in this case, when the cylindrical non-magnetic rotor 92 is formed by a mold or the like, at the same time, a hole or the like is provided in a portion into which the magnetic tack is driven. The detected object rotor 9 can be obtained in an extremely simple manner.

By the way, also in the second to sixth embodiments, the number or arrangement period of the detected parts as the detected object rotor is arbitrarily set according to the desired rotation angle information. However, as described above, between the number or arrangement period of the detected portions and the output of the magnetic sensor 3, (a) when the number of detected portions is increased, the deflection angle of the magnetic vector is increased. It becomes smaller, and the S / N ratio of the electric signal converted by the magnetoresistive element MRE deteriorates. (B) If the arrangement intervals (intervals) of the detected parts are the same, it is better to narrow the width (the length in the rotation direction) of the magnetic material that constitutes each of the detected parts. Grows. That is, the S / N ratio of the electric signal converted by the magnetoresistive element MRE is improved. Further, the waveform of this electric signal also becomes a waveform that is closer to a sine wave and has less distortion. There is a relationship such as. For this reason, in any of the above-described embodiments, it is desirable in practice to perform optimization in consideration of such a relationship, including the shapes of the detected portions.

Although the above-described several embodiments have been shown as the magnetic sensor detected object rotor, the structure of the detected object rotor according to the present invention is not limited to the structures according to the respective embodiments. That is, the rotor of the magnetic sensor for the magnetic sensor is essentially the rotary shaft 1 with respect to the magnetic resistance element.
The magnetic body that imparts a magnetic vector change corresponding to the rotation of the rotor has a detected portion having a structure that is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor in a cross section perpendicular to the rotation axis 1. I wish I had it.

Further, in the rotation detecting device according to each of the above-described embodiments, the magnetic sensor having the "vertically arranged" magnetoresistive element in which "waveform cracking" or the like does not occur is adopted. However, the structure of the magnetic sensor employed is arbitrary, and it goes without saying that the magnetic sensor may include the magnetic resistance elements arranged in “parallel”. Even if it has this "parallel arrangement" of magnetoresistive elements,
As described above, depending on the mounting position and the like, “waveform cracking” or the like does not occur and a high-level sensor signal is output.

[0107]

As described above, according to the detected object rotor for a magnetic sensor of the present invention, the magnetoresistive element to which a bias magnetic field is applied has a simpler structure which is inexpensive. Therefore, it becomes possible to suitably apply the magnetic vector change.

Further, according to the method for manufacturing a magnetic sensor detected object rotor according to the present invention, a magnetic sensor detected object rotor having such a simple structure can be easily and highly efficiently manufactured. .

Further, according to the rotation detecting device of the present invention, it is possible to perform rotation detection simply and with sufficient accuracy by using such a rotor to be detected.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a detected object rotor according to the present invention.

FIG. 2 is a front view showing a positional relationship between the detected object rotor and a magnetic sensor.

FIG. 3 is a diagram showing an output characteristic of a rotation detection device using the detected object rotor.

FIG. 4 is a plan view and a cross-sectional view showing a manufacturing process of the same detected object rotor.

FIG. 5 is a perspective view showing a second embodiment of the detected object rotor according to the present invention.

FIG. 6 is a perspective view showing a third embodiment of the rotor to be detected according to the present invention.

FIG. 7 is a perspective view showing a fourth embodiment of the rotor to be detected according to the present invention.

FIG. 8 is a perspective view showing a fifth embodiment of the rotor to be detected according to the present invention.

FIG. 9 is a perspective view showing a sixth embodiment of the object rotor according to the present invention.

FIG. 10 is a perspective view and a graph showing resistance value change characteristics of a magnetoresistive element.

FIG. 11 is a perspective view showing a sensor configuration in which magnetic resistance elements are arranged in parallel.

FIG. 12 is a graph showing resistance value change characteristics of a magnetoresistive element having the same configuration.

FIG. 13 is a perspective view showing a sensor configuration in which magnetic resistance elements are vertically arranged.

FIG. 14 is a graph showing resistance value change characteristics of the magnetoresistive element having the same configuration.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Detected rotary shaft, 2 ... Detected body rotor, 21 ... Detected part, 22 ... Rotating shaft insertion hole, 3 ... Magnetic sensor, 31 ... Sensor part, 32 ... Bias magnet, 4 ... Processing circuit, 5 ... Covered Detecting body rotor, 51 ... Detected portion, 52 ... Window hole, 53 ... Support member, 6 ... Detected body rotor, 61 ... Detected portion (magnetic wire), 7 ... Detected body rotor, 71 ... Detected portion (Magnetic wire), 72 ... Resin support member (non-magnetic rotor), 8 ...
Detected object rotor, 81 ... Detected portion (magnetic pin), 82
... Resin support member (non-magnetic rotor), 9 ... Detected rotor, 91 ... Detected portion (magnetic tack), 92 ... Resin support member (non-magnetic rotor), MRE ... Magnetoresistive element.

Claims (19)

[Claims] 1. A rotor for a magnetic sensor to be detected, which is mounted on a rotating shaft to be detected and applies a magnetic vector change corresponding to rotation of the rotating shaft to a magnetoresistive element to which a bias magnetic field is applied from behind. A structure in which a magnetic body that imparts a magnetic vector change corresponding to the rotation of the rotating shaft to the magnetoresistive element is present in a dot shape with a predetermined arrangement period on the outer circumference of the rotor in a cross section perpendicular to the rotating shaft. A detected object rotor for a magnetic sensor, comprising: a detected part having the detected part. 2. The magnetic sensor cover according to claim 1, wherein the detected portion is a rectangular plate-shaped protruding portion that is bent at a right angle around a magnetic plate mounted on the rotary shaft. Detector rotor. 3. The detected portion is made of a cylindrical magnetic material having window holes periodically arranged in the circumferential direction of the outer peripheral surface, and the detected magnetic material is supported by an appropriate support member mounted on the rotary shaft. The detected object rotor for a magnetic sensor according to claim 1. 4. The detected object rotor for a magnetic sensor according to claim 1, wherein the detected portion is formed by arranging substantially U-shaped wire rods made of a magnetic material in a radial pattern centered on an axis of the rotary shaft. . 5. The detected part is a magnetic wire rod which is periodically embedded along an outer peripheral surface of a cylindrical non-magnetic rotor mounted on the rotary shaft along the circumferential direction thereof and in parallel with the rotary shaft. The detected object rotor for a magnetic sensor according to claim 1. 6. The detected part is a magnetic pin arranged periodically along the outer periphery of the disk-shaped non-magnetic rotor mounted on the rotary shaft and in parallel with the rotary shaft. Item 1. A detected object rotor for a magnetic sensor according to Item 1. 7. The magnetic member according to claim 1, wherein the detected portion is a magnetic material stud that is periodically arranged along the circumferential direction on the outer peripheral surface of a cylindrical non-magnetic material rotor mounted on the rotating shaft. Detected object rotor for sensor. 8. A rotor for a magnetic sensor to be detected, which is mounted on a rotary shaft to be detected and which applies a magnetic vector change corresponding to rotation of the rotary shaft to a magnetoresistive element to which a bias magnetic field is applied from behind. A method of manufacturing, which comprises punching out a disk having a hole fitted into the rotating shaft from a magnetic plate and strip-shaped teeth radially protruding from a circumference of a circle centered on the hole at predetermined intervals, A method of manufacturing a rotor to be detected for a magnetic sensor, comprising: a step of bending the strip-shaped teeth of a punched magnetic material plate disk at a right angle at their roots. 9. A detection object rotor for a magnetic sensor, which is mounted on a rotating shaft to be detected and which applies a magnetic vector change corresponding to rotation of the rotating shaft to a magnetoresistive element to which a bias magnetic field is applied from the back. A manufacturing method, which is a step of holding a large number of wire rods or pins made of a magnetic material in parallel and at predetermined intervals along an inner surface of a mold corresponding to the rotor shape, and pouring a non-magnetic material into the mold and holding it. A method of manufacturing a rotor to be detected for a magnetic sensor, comprising the step of fixing a magnetic wire or a pin. 10. A detection object rotor for a magnetic sensor, which is mounted on a rotating shaft as a detection target and applies a magnetic vector change corresponding to rotation of the rotating shaft to a magnetoresistive element to which a bias magnetic field is applied from the back. A manufacturing method, which is a step of holding a large number of wire rods made of a magnetic material in parallel and at predetermined intervals along an inner surface of a mold corresponding to the rotor shape, and pouring a non-magnetic material into the mold to hold the magnetic material. A step of fixing the wire rod; and a step of cutting the non-magnetic material solid in which the magnetic substance wire rod is fixed and embedded into slices according to a desired rotor thickness. Production method. 11. A detected body rotor for a magnetic sensor, which is mounted on a rotating shaft to be detected and applies a magnetic vector change corresponding to rotation of the rotating shaft to a magnetoresistive element to which a bias magnetic field is applied from the back. A manufacturing method, which is a step of holding a large number of tacks made of a magnetic material along a inner surface of a mold corresponding to the rotor shape at predetermined intervals, and pouring a non-magnetic material into the mold to hold the magnetic material tacks. A method of manufacturing a detected object rotor for a magnetic sensor, comprising: a step of fixing the detected object rotor. 12. An object to be detected, which is mounted on a rotary shaft to be detected and has a structure in which a magnetic material is present in a dot shape with a predetermined arrangement period on the outer periphery in a cross section perpendicular to the rotary shaft. A detection body rotor, a bias magnet that generates a bias magnetic field toward the detection target portion of the detection target rotor, and a magnetic vector that is disposed in the generated bias magnetic field and that accompanies the rotation of the detection target rotor. And a signal processing circuit for obtaining the rotation information of the rotation axis to be detected by processing the converted electric signal as required. The rotation detection device. 13. The detection object rotor comprises a detection part in which a strip-shaped protruding portion is bent at a right angle around a magnetic plate mounted on the rotating shaft. 12. The rotation detection device according to item 12. 14. The object rotor comprises a magnetic material of cylindrical shape having window holes periodically arranged in a circumferential direction of an outer peripheral surface thereof, which is supported by an appropriate supporting member mounted on the rotary shaft. The rotation detection device according to claim 12, further comprising a detection unit. 15. The detection object rotor comprises a detection part in which substantially U-shaped wire rods made of a magnetic material are arranged radially around the axis of the rotating shaft. 12. The rotation detection device according to item 12. 16. The magnetic wire rod, wherein the rotor to be detected is periodically embedded in the outer peripheral surface of a cylindrical non-magnetic rotor mounted on the rotary shaft, along the circumferential direction thereof and in parallel with the rotary shaft. 13. The rotation detecting device according to claim 12, further comprising a detected part consisting of. 17. The rotor to be detected comprises magnetic pins arranged periodically along the outer periphery of the disc-shaped non-magnetic rotor mounted on the rotary shaft and in parallel to the rotary shaft. The rotation detection device according to claim 12, comprising a detected part. 18. The detection object rotor comprises a detection part made of magnetic material studs periodically arranged along the circumferential direction on the outer peripheral surface of a cylindrical non-magnetic material rotor mounted on the rotating shaft. 13. The rotation detecting device according to claim 12, which is a rotary encoder. 19. The magnetoresistive element is composed of two elements which are arranged at an angle of 45 degrees with respect to the magnetic force lines emitted from the bias magnet and which are arranged perpendicularly to the magnetized surface of the bias magnet. The rotation detection device according to any one of 12 to 18.