JP2003004484A - Rotation sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp the location of a rotator in the circumferential direction with high accuracy and eliminate magnetic effects to another track. SOLUTION: In a polarized area formed in the outer circumferential part of the rotator 11, different magnetic poles are arranged alternately along the circumferential direction, and comprise a recording polarized part 11a formed in part over the whole circumference of the outer circumferential part. By magnetically detecting point in a track which contains the recording polarized part 11a, this rotation sensor determines whether the detected point is a point on the recording polarized part 11a or a point which is not on the polarized area. By narrowing the interval between the adjacent magnetic poles on the recording polarized part 11a, the polarized area becomes an aggregate of relatively fine magnetic poles to weaken magnetic forces.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rotation sensor. More specifically, the present invention relates to the configuration of a rotation sensor that obtains magnetic information of a magnetized region provided on a peripheral surface or a main surface of a rotating body to detect a rotation amount and a circumferential position of the rotating body.

[0002]

2. Description of the Related Art Some direct drive type motors are provided with a magnetized area in a rotor so that the amount of rotation of the rotor and the origin position can be detected by a magnetoresistive sensor (MR sensor). For example, the amount of rotation of the rotor can be detected by detecting the phase-shifted A and B phase signals by the magnetized region that circulates around the outer periphery of the rotor. Further, the magnetizing point is provided only at one position on the rotor in the circumferential direction, and the origin position information can be obtained by detecting the one-phase Z-phase signal when the origin point sensor passes the magnetizing point.

Further, in the magnetic rotary encoder disclosed in Japanese Patent Publication No. 4-77245, a U-shaped track (occupying approximately half of the circumference) continuously magnetized in the circumferential direction of the main surface as shown in FIG. (Track) 101 is formed. In this case, since it is possible to determine whether the current position is on the right half circle or the left half circle by the track 101, it is possible to roughly grasp the current circumferential position even before the origin position is detected.

[0004]

However, according to the above magnetic rotary encoder, the U-shaped track 1 is used.
When the magnetism of 01 is strong, there is a problem that the magnetic information of other tracks is affected. Further, as shown in FIG. 11, since the magnetoresistive sensor 102 needs to have an extra pattern arranged even outside the track 101, there is a problem that the chip area becomes large and the size becomes large.

Therefore, it is an object of the present invention to provide a rotation sensor capable of accurately grasping the circumferential position of a rotating body and eliminating magnetic influence on other tracks.

[0006]

In order to achieve the above object, the invention according to claim 1 is a magnetizing area formed on an outer peripheral portion of a rotating body, and a magnetic detecting section for detecting magnetism of the magnetizing area. In the rotation sensor for detecting the amount of rotation and the position in the circumferential direction of the rotating body, different magnetic poles are alternately arranged along the circumferential direction in the magnetized region, and the magnetized region is formed on a part of the entire circumference of the outer peripheral portion. It has a recording magnetizing section.

This rotation sensor magnetically detects any point on the track including the recording magnetized portion to determine whether the detected point is a point on the recording magnetized portion or on the magnetized area. It is possible to determine if there is no point. And
From this determination result, the absolute position of the magnetized area can be detected.

Moreover, by narrowing the interval between adjacent magnetic poles on the recording magnetized portion, the magnetized region becomes a set of relatively fine magnetic poles, and the magnetic force becomes weak. In this case, the influence of magnetism on other adjacent magnetized regions (tracks) is reduced.

According to a second aspect of the present invention, in the rotation sensor according to the first aspect, the recording magnetized portion is formed only on a half circumference of the outer peripheral portion. Therefore, it is possible to determine in which of the bisected 180 ° regions the detected point on this track is located.

According to a third aspect of the present invention, in the rotation sensor according to the first aspect, signal processing is performed by a sum of squares of signals of two phases obtained from the recording magnetizing unit. In this case, 2
By shifting the phase of two signals, a discontinuous signal can be regarded as a continuous signal.

According to a fourth aspect of the present invention, in the rotation sensor according to the first aspect, the magnetizing region is formed by a second magnetic pole having different magnetic poles alternately arranged along the circumferential direction and formed on the entire circumference of the outer peripheral portion.
Recording magnetically polarized portion, and the magnetic pole spacing of the first recording magnetically polarized portion is formed to be three times or less than the magnetic pole spacing of the second recording magnetically polarized portion. In this case, the influence of the magnetic force of the first recording magnetized portion on the second recording magnetized portion and other tracks is small.

According to a fifth aspect of the present invention, in the rotation sensor according to the first aspect, the boundary signal of the recording magnetized portion is used as the origin signal of the rotating body. In this case, the recording magnetizing unit and the detection sensor obtain a position signal for each 180 degree region and a boundary signal for each 180 degrees, and this boundary signal can be used as an origin signal. Therefore, a reference position sensor or the like for issuing a one-pulse Z-phase signal is unnecessary.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

1 to 8 show a rotation sensor 1 of the present invention. The rotation sensor 1 includes a magnetized region formed on the outer peripheral portion of the rotating body 11 and a magnetic detection unit 1 for detecting the magnetism of the magnetized region.
2 for detecting the amount of rotation and the position in the circumferential direction of the rotating body 11, and in the present embodiment, the second recording magnetized portion 11b circumferentially formed on the outer peripheral portion and the second recording magnetized portion 11b. A first concentric with the recording magnetized portion 11b and formed on a part of the circumference.
Recording magnetizing portion 11a. The rotating body 11 is, for example, a magnetic drum used in an encoder or the like (hereinafter referred to as “rotating magnetic drum 11”).

The outer peripheral portion in this specification includes not only the peripheral surface of the rotating magnetic drum 11 but also the main surface (top surface or bottom surface). Therefore, the recording magnetized portions 11a and 11b provided on the peripheral surface of the rotary magnetic drum 11 in the present embodiment may be provided on the upper surface or the bottom surface of the rotary magnetic drum 11.

First, as shown in FIG. 2, the outer peripheral portion of the rotary magnetic drum 11 is a 360 ° -magnetized second recording magnetizing portion 11b in which different magnetic poles are alternately arranged in the circumferential direction.
Is formed in a ring shape. If you show the actual magnetic pole in detail,
As shown in FIG. 7, the portions adjacent to each other are magnetized so as to be in opposite directions, and are a collection of small magnetic poles arranged in opposite directions. However, in FIG. 1 and FIG. 2, they are simplified for convenience. . At this time, when the distance between the adjacent NS poles is λ, λ is preferably in the range of 0.05 to 5 mm, more preferably about 0.8 mm.

On the other hand, the first recording magnetized portion 11a is concentric with the second recording magnetized portion 11b and is formed in a part of the circumference, and different magnetic poles are alternately arranged along the circumferential direction. It has been done. As shown in FIG. 1, in the present embodiment, the first recording magnetized portion 11a is provided so as to have a central angle of 180 degrees in a half circumference of the outer peripheral portion, and the opposite half circumference is a non-magnetized portion. As a result, a magnetized region and a non-magnetized region are formed every 180 degrees.

Further, the magnetic detection section (sensor module)
Reference numeral 12 is arranged so as to face the rotary magnetic drum 11 so as to be close to the second recording magnetized portion 11b (FIG. 2). Here, the magnetic detection unit 12 has two magnetoresistive (MR) elements 12b, which are arranged in a staggered manner in the circumferential direction and are out of phase with the second recording magnetized section 11b.
Two signals of phase and B phase are obtained. In this embodiment, the two magnetoresistive (MR) elements 12b are arranged so as to be displaced by an electrical angle of 90 degrees. The gap between the rotating magnetic drum 11 and the magnetoresistive (MR) element 12b is adjusted by observing the amplified output waveform. The gap width is about 0.3 mm, but it should be adjusted appropriately.

Further, similarly to this, another magnetic detector 12
Are arranged close to the first recording magnetized portion 11a. This magnetic detection unit 12 has two magnetic resistances (M
(R) element 12b, and two signals of C phase and D phase, which are out of phase with each other, are obtained from the first recording magnetized portion 11a. Similar to the AB phase, the outputs of the C phase and the D phase are extracted with a phase shift of 90 degrees (Fig. 6).

The C-phase and D-phase signals extracted from the magnetoresistive (MR) element 12b are respectively amplified, and the digital values after A / D conversion are summed squared. That is, the 180 degree detection signal Z = Csin ² Ve + Dsin ² Vd (Ve is C
The output voltage of the phase, Vd is the output voltage of the D phase), and the image is as shown in the Lissajous figure shown in FIG. In the present embodiment, the maximum value of Z is set to 1 level and is approximately 0.5.
Is compared as a threshold value to obtain a digital signal. That is, a signal having a level of 0.5 or higher is taken out as a signal of 1, and a signal having a level of 0.5 or less is taken out as 0. As a result, the first recording magnetizing unit 1
A signal of 1 can be obtained from the range occupied by 1a, and a signal of 0 can be obtained from the remaining range. Here, the threshold value is 0.5
However, any threshold value of 0.1 to 0.9 level may be appropriately used.

Here, the magnetic effect on the second recording magnetized portion 11b (and other tracks) can be reduced by narrowing the interval between adjacent magnetic poles in the first recording magnetized portion 11a. Becomes In this case, it is preferable that the magnetic pole spacing of the first recording magnetized portion 11a be equal to or less than three times the magnetic pole spacing of the second recording magnetized portion 11b, and more preferably the magnetic pole spacing of approximately the same distance. is there. By the way, the preferable value of the magnetization gap between the AB phase and the CD phase is 0.
It is 5 to 1 mm, but is not limited to this.

Further, the start end (or end) of the first recording magnetized portion 11a can be aligned with the origin position of the rotary magnetic drum 11. In this case, as shown in FIG. 8, a transient portion is generated as a boundary output signal between the first recording magnetized portion (steady magnetized portion in the figure) 11a and the non-magnetized portion (demagnetized portion in the figure). Therefore, the origin edge is determined by using, for example, a point obtained by inverting this output signal with a threshold value as the origin signal. According to the present embodiment, the first recording magnetizing unit 11
Since the boundary signal of a can be used as the origin signal of the rotary magnetic drum 11, it is not necessary to provide the one-point magnetized origin detecting magnetizing portion for the Z phase on the outer peripheral portion of the rotary magnetic drum 11. . Therefore, the first recording magnetizing unit 11a and the magnetic detecting unit 12 receive the 180 degree region signal and 1
It has two functions of 80 degree point reference signal.

Here, the magnetic detector 12 has a structure in which a magnetoresistive (MR) element 12b is mounted on a flat surface on one side (lower side in FIG. 2) of a flat plate-shaped circuit board 12a. Is. As shown in FIG. 3 and FIG. 4, the magnetoresistive (MR) element 12b includes a chip substrate 12b1 made of a photosensitive glass plate having a square planar shape. Of the above, the second
A stripe-shaped ferromagnetic thin film 12b2 having a magnetoresistive effect such as a Ni—Fe film is formed on a flat surface on one side of FIG. 3 facing the recording magnetized portion 11b by using a vapor deposition device or the like. And is patterned by a photolithography process. The stripe-shaped ferromagnetic thin film 12b2 is
Plural pieces are arranged substantially in parallel, and each of them is formed with a line width of about 8 μm. In addition, the electrode pattern 12
b3 is also processed at the same time.

At both ends of each of the ferromagnetic thin film bodies 12b2, a surface auxiliary electrode portion 12b as shown in the figure is formed.
3 are connected to each other. At this time, the through-hole electrode 1 is formed in the portion corresponding to each surface electrode portion 12b3.
2b4 is provided so as to penetrate the chip substrate 12b1 in the thickness direction. In forming these through-hole electrodes 12b4, first, the holes of the photosensitive glass plate constituting the chip substrate 12b1 are exposed to light, developed by heat treatment, and then etched with hydrofluoric acid or the like. Make holes. Further, the through hole electrode 12b4 is formed by filling the processed hole with silver paste and then firing. On the extended end side of the through-hole electrode 12b4, that is, on the surface of the back side of the chip substrate 12b1 located on the lower side in FIG. 3, the back side auxiliary electrode section 12b5 is formed by a screen printing and firing process of silver paste. Has been done. Also, the solder bumps 12b of the back surface auxiliary electrode portion 12b5
5'is formed by solder paste screen printing and a reflow process.

Further, an inorganic first protective film 12b6 made of SiO ₂ or the like is formed on the ferromagnetic thin film body 12b2 and the surface auxiliary electrode portion 12b3 by sputtering so as to have a film thickness of about 1 μm. Along with
Further thereon, a second protective film 12b7 made of epoxy resin or the like is formed by screen printing or the like with a film thickness of about 10 to 20 μm. A large number of magnetoresistive (MR) elements 12b having such a structure are integrally formed on a wafer and then divided into chips by a dicing process to form individual elements.

The magnetoresistive (MR) element 12b having such a structure is, as described above, a flat circuit board 12a.
Although fixed to the flat surface on one side (lower side in FIG. 2), the epoxy resin 12 having low viscosity and good fluidity is provided between the magnetoresistive (MR) element 12b and the circuit board 12a.
c is poured and hardened by the underfill process, whereby the mechanical strength is improved and, at the same time, electromigration is prevented and electrical reliability is improved.

At this time, the circuit board 12a is formed in a substantially rectangular plane shape slightly larger than the chip board 12b1 of the magnetoresistive (MR) element 12b described above, and the other side (upper side in FIG. 2) of the circuit board 12a. An IC chip 12d1 including an initial stage amplifier (amplifying circuit) that amplifies the detection output from the magnetoresistive (MR) element 12b and other electronic components 12d2 are mounted on the surface portion. Among them, the input terminal of the first-stage amplifier (amplification circuit) is provided on the surface portion on one side (the upper side in FIG. 2) of the circuit board 12a, and particularly in the vicinity of the magnetoresistive (MR) element 12b described above. It is arranged. Then, the magnetoresistive (MR) element 1 is connected to the input terminal of the first-stage amplifier circuit.
The 2b chip substrate 12b1 is surface-mounted at the same time as other electronic components by a mounter or the like to be superposed on the circuit substrate 12a, and thereafter, the connection with the circuit substrate is completed by reflow.

Further, a bias magnet 12d3 for applying a magnetic bias to the above-mentioned magnetoresistive (MR) element 12b together with the above-mentioned electronic parts is provided on the plane portion on the other side (upper side in FIG. 2) of the circuit board 12a. It is installed. The bias magnet 12d3 is used for the chip substrate 12
It is arranged at a substantially central position corresponding to b1 and is fixed to the circuit board 12a side by applying an adhesive having a high curing speed. The bias magnet 12d3 may be temporarily fixed with an instant adhesive or the like and then fixed with an epoxy resin or a UV resin. At this time, the bias magnet 12d3 is formed in a plane substantially rectangular shape smaller than the circuit board 12a described above.
The rectangular side portions of the 2a and the bias magnet 12d3 that correspond to each other are positioned so as to be in a parallel state.

On the bias magnet 12d3, different magnetic poles are magnetized so as to divide the plane rectangular shape into two.
The magnetic domain of the bias magnet 12d3 formed in the rectangular shape is formed so as to be parallel to each side portion of the rectangular shape, whereby the above-described magnetoresistive (MR) element 12 is formed.
Magnetic flux is formed in a direction orthogonal to the stripe-shaped ferromagnetic thin film body 12b2 in b.
More specifically, the planar rectangular bias magnet 12d
3 is a circuit board 1 with respect to the chip board 12b1 described above.
It is mounted so as to be in a substantially parallel state via 2a,
The center position of the bias magnet 12d3 is the chip substrate 1
It is fixed at a position that coincides with the center position of 2b1.

At this time, the size and type of the bias magnet 12d3 and the distance between the bias magnet 12d3 and the above-mentioned magnetoresistive (MR) element 12b are set so that the midpoint of the signal magnetic field is approximately at the center of the dynamic range of resistance change. Is set so that the saturation point of the resistance change is applied in the direction orthogonal to the extending direction of the ferromagnetic thin film body 12b2. For example, the magnetic flux density (horizontal axis) of the bias magnet 12d3 in the present embodiment is plotted against the resistance change rate (vertical axis; MR characteristic) of one of the magnetoresistive (MR) elements 12b shown in FIG. , The magnetic field obtained from the second recording magnetized portion 11b of the rotating magnetic drum 11 is set to, for example, 8 mT.
It can be set to a practical range of ± 4 mT or less centered on 0.

At this time, the magnetic detection section (sensor module) 12 in which the magnetoresistive (MR) element 12b is attached to the circuit board 12a, and the second recording magnetized section 11b of the rotary magnetic drum 11 described above. The gap between the two is adjusted while observing the characteristics of the detection output (MR output), and then fixed. For example, if the signal magnetic field is too strong, the Lissajous waveform will be rectangular rather than circular. The ideal signal magnetic field is that the Lissajous waveform is as large as possible and circular, but in order to obtain such an output waveform, the dynamic range of the MR characteristic is lowered as described with reference to FIG. Without applying the bias magnetic field such that the linear region of the MR characteristic becomes the center of the signal magnetic field, a circular Lissajous waveform as shown in FIG. 6 can be obtained.

As described above, the rotation sensor 1 of this embodiment
Can accurately grasp the circumferential position of the rotating magnetic drum 11, and can eliminate the magnetic influence on other tracks such as the second recording magnetized portion 11b. Moreover,
Since the first recording magnetizing unit 11a can use the same magnetizing device and the same sensor as those on the AB phase side, it is advantageous in terms of design and equipment, leading to cost reduction. On the side of the first recording magnetizing unit 11a, a position signal for each 180 degree region and a boundary signal for each 180 degrees can be obtained even though it is a single sensor, and since this boundary signal can be used as an origin signal, the reference position No sensor is required.

The above-described embodiment is an example of the preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the first recording magnetizing unit 11a
Is provided at a central angle of 180 degrees in half of the outer peripheral portion, but may be magnetized at an arbitrary angle within a practical range, for example, 5 to 175 degrees. However, the case where the magnetizing range exceeds 180 degrees is not particularly excluded.

Further, although the through-hole type is used as the magnetoresistive (MR) element 12b, an element using a general glass substrate may be used.

Further, in this embodiment, the rotating magnetic drum 11 is used.
And the magnetoresistive (MR) element 12b are used, but the present invention is not limited thereto. For example, a resolver using a toothed drum coil pickup may be applied instead of them.

Further, in the present embodiment, the preferred example in which the rotation sensor 1 is applied to the encoder of the rotary motor has been shown, but the present invention is not limited to the rotary motor and can be applied to, for example, a linear motor.

In this embodiment, the output of the magnetoresistive (MR) element 12b is sum of squares.
The outputs or the outputs after amplification may be directly compared, and the OR output of the C phase and C phase inverter outputs and the D phase may be used as the logical output sum.

Further, in the present embodiment, the square sum of the outputs of the C phase and the D phase is calculated and the signal processing is performed, but the signal processing may be performed by peak hold, for example. That is, it is possible to perform signal processing by charging only the peak of the signal waveform with a capacitor and connecting them to obtain a continuous signal.

Further, in the present embodiment, as shown in FIG. 7, the magnetized regions are magnetized so that mutually adjacent portions are in opposite directions. For example, as shown in FIG. 9, the dipoles are located in the radial direction. The small magnetic poles may be magnetized so as to be alternately arranged in the circumferential direction.

Further, in the present embodiment, the amount of rotation and the circumferential position of the rotating body 11 is detected by utilizing magnetism, but other means, for example, an optical system for detecting the light irradiated to the slit is used. The amount of rotation and the like can be detected by means, or by reading the color tone of the stripe pattern.

[0041]

As is apparent from the above description, according to the rotation sensor of the first aspect, the detected point is recorded by magnetically detecting any point on the track including the recording magnetized portion. The direction of the rotating body at the time of detection can be grasped by discriminating whether or not it is a point in the magnetized portion. Therefore, for example, even when the power is newly turned on to the motor and the position memory of the rotating body is not backed up, it is possible to confirm which region the rotating body is rotating. In this case, it is possible to improve efficiency by omitting the unnecessary operation after that, and it is also useful for eliminating malfunction and ensuring safety. Further, by detecting the absolute position of the 180 degree region, it can be utilized as a logic signal for control using an encoder.

In addition, according to this rotation sensor, the influence of magnetism on other magnetized regions (tracks) can be eliminated by narrowing the gap between adjacent magnetic poles in the recording magnetized portion. Further, it is not necessary to dispose an extra pattern of the magnetoresistive sensor, and the size can be reduced.

According to the rotation sensor of the second aspect, since the recording magnetized portion is formed only on the half circumference of the outer peripheral portion, the rotating body rotates on either side of the bisected 180 degree region. Can be detected.

Further, according to the rotation sensor of the third aspect, since the signal processing is performed by the sum of squares of the signals of the two phases obtained from the recording magnetizing unit, the discontinuous signal is recognized as a continuous signal and the recording is performed without time lag. The magnetized portion can be detected accurately.

According to the rotation sensor of the fourth aspect, since the magnetic pole spacing of the recording magnetizing portion is at most three times the magnetic pole spacing of the second recording magnetizing portion, the second recording magnetizing portion is provided. And the influence of magnetic force on other tracks can be reduced.

According to the rotation sensor of the fifth aspect, since the boundary signal of the recording magnetized portion is used as the origin signal of the rotating body, a reference position sensor for issuing a one-pulse Z-phase signal is unnecessary, and the structure Can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a perspective view of a rotating body provided with a first recording magnetized portion and a second recording magnetized portion on a peripheral surface.

FIG. 2 is an explanatory plan view showing a magnetic detection unit and its surroundings.

3 is a longitudinal cross-sectional explanatory view showing the structure of a magnetoresistive (MR) element used in the rotation sensor shown in FIG.

4 is a plan view showing the structure of a magnetic sensing section of the magnetoresistive (MR) element shown in FIG.

5 is a diagram showing an example of resistance change characteristics of a magnetoresistive (MR) element used in the rotation sensor shown in FIG.

FIG. 6 is a graph showing an example of C-phase and D-phase output waveforms obtained from the first recording magnetized portion, and a Lissajous figure showing an image of the output obtained by the sum of squares signal.

FIG. 7 is a schematic view showing an actual state of magnetic poles when different magnetic poles are alternately arranged along the circumferential direction.

FIG. 8 is a graph showing an example of a waveform in the vicinity of the origin position when the starting end or the terminating end of the first recording magnetized portion is aligned with the origin position of the rotating magnetic drum.

FIG. 9 is a schematic view showing another state of an actual magnetic pole when different magnetic poles are alternately arranged in sequence along the circumferential direction.

FIG. 10 is a diagram showing an example of a conventional U-shaped track continuously magnetized in the circumferential direction of the main surface of the rotating body.

FIG. 11 is a diagram showing an example of the shape of a conventional magnetoresistive sensor.

[Explanation of symbols]

1 rotation sensor 11 Rotating magnetic drum (rotating body) 11a First recording magnetization portion (magnetization area) 11b Second recording magnetized portion (magnetized area) 12 Magnetic detector (sensor module)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruhiro Tsuneda             2 Stock Association at 10801 Hara-mura, Suwa-gun, Nagano Prefecture             Inside Sanwa Seiki Seisakusho Suwa Minami Factory (72) Inventor Akihiro Ito             2 Stock Association at 10801 Hara-mura, Suwa-gun, Nagano Prefecture             Inside Sanwa Seiki Seisakusho Suwa Minami Factory F term (reference) 2F077 AA31 AA38 CC02 CC08 NN03                       NN04 NN21 NN24 NN27 PP06                       PP14 PP19 PP26 QQ05 QQ12                       TT00 VV01                 2F103 BA32 BA42 CA01 DA01 DA13                       EA04 EA12 EA13 ED00

Claims (5)

[Claims] 1. A magnetized region formed on an outer peripheral portion of a rotating body, and a magnetism detection unit for detecting magnetism in the magnetized region,
In the rotation sensor that detects the rotation amount and the circumferential position of the rotating body, in the magnetized area, different magnetic poles are alternately arranged along the circumferential direction, and the recording is formed on a part of the entire circumference of the outer peripheral portion. A rotation sensor having a magnetized portion. 2. The rotation sensor according to claim 1, wherein the recording magnetized portion is formed only on a half circumference of the outer peripheral portion. 3. The signal processing is performed by sum of squares of signals of two phases obtained from the recording magnetizing unit.
The described rotation sensor. 4. The magnetized area has a second recording magnetized portion formed by arranging different magnetic poles alternately along the circumferential direction and formed on the entire circumference of the outer peripheral portion, wherein the first recording is performed. 2. The rotation sensor according to claim 1, wherein the magnetic pole spacing of the magnetized portion is formed to be three times or less than the magnetic pole spacing of the second recording magnetized portion. 5. The rotation sensor according to claim 1, wherein a boundary signal of the recording magnetized portion is used as an origin signal of the rotating body.