JPS58155312A - Magnetic rotary sensor - Google Patents

Abstract

PURPOSE:To improve mass productivity by making a substrate for a magnetic resistance effect element part small and forming the magnetic resistance effect element on the substrate in a unitary body, to improve the arranging accuracy of the magnetic resistance element, and also to eliminate the mutual magnetic interface between encoder parts and position detecting parts. CONSTITUTION:A magnetic body attaching part and the magnetic resistance effect element (MR element) part are divided into encoder parts and position detecting parts, respectively. The position detecting parts of the magnetic body attaching part D are subdivided in correspondence with the phase number of a brushless motor. The directions of the magnetic recording of detecting tracks 40-43 are made different. The MR elements 61-63 for the first - third phases are arranged so as to face the detecting tracks associated with the magnetic bodies approximately linearly. The directions of the magnetic signal recording of the encoder parts and the position detecting parts are made to intersect at a right angle. Namely arrangement is sequentially made in the circumferential direction and at the inside and outside of the radial direction. Thus the mutual interference between magnetic recording can be eliminated. The magnetic signal recording N and S in each detecting track at the position detecting part are arranged so that the direction in each track is reversed with respect to the direction in the other track. Therefore the magnetic interference between each of the detecting tracks can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic rotation sensor, and is a position detection method for a brushless motor in which an encoder section and a position detection section in a brushless motor are integrated, and a magnetoresistive element section is arranged facing each other. This article relates to a magnetic rotation sensor related to an attached rotation sensor.

First, the prior art will be explained in Section 1.1@.

Here, FIG. 1 is a schematic configuration diagram showing a magnetic rotation sensor using a brushless motor, a magnetoresistive effect element part, and a magnetic body attachment part having a magnetic body on a desk, and FIG. 2 shows the magnetic rotation sensor. FIG. 2 is an enlarged explanatory diagram of the related configuration of a body attachment part and a magnetoresistive element part.

The illustrated magnetic rotation sensor is an example of a three-phase, four-pole magnetic rotation sensor in which an encoder section and a brushless motor position detection section are integrated.

That is, a rotation sensor is attached to a brushless motor l, a desk 3 is attached to the rotating shaft 2, and a magnetic body 4A is attached to the desk 3 to form a magnetic body attachment part D1, which is opposed to the disk 3. Mount the magnetoresistive element section 6A on the mounting base 5.
It is designed to be attached to a fixed part of the brushless motor 1.

As shown in FIG. 2, the outer peripheral portion 40At of the magnetic body 4A is used as an encoder section, and magnetic signals N, S
are sequentially recorded in the circumferential direction, and the inner peripheral part 41A is used for the position detection part of the brushless motor 1, and magnetic signals S and N are recorded in the circumferential direction in the same manner corresponding to the magnetic poles of the motor 1. This is what is being done.

Further, facing each of these magnetic signals, the magnetoresistive elements 60A and 618 to 6 of the magnetoresistive element section 6A
3A is arranged, among which magnetoresistive element 60A
is a wandering encoder part, and the same 61A ~
63A is arranged at a position shifted by 120 degrees in electrical angle, and each generates three-phase position signals.

The above is an example of a magnetic rotation sensor that includes an encoder section and something that generates a position detection signal.

However, in the conventional technology, there is only one detection track on the inner circumferential portion 41A of the position detection section, and facing thereto, there are magnetoresistive elements 61A to 61A for position detection. 63A are arranged 120 degrees apart in electrical angle, so it is possible to place magnetoresistive elements on the same substrate, for example, just as magnetoresistive elements are made by vacuum-depositing permalloy on a substrate such as glass and then etching it. If it is manufactured in one piece, the area of the board becomes very large, which reduces productivity during mass production and increases the cost.

Furthermore, magnetic recording for the position detection section and encoder section is
As mentioned earlier, since the circumferential directions are in the same direction,
They also have the disadvantage that stable signals cannot be obtained due to mutual magnetic interference.

The present invention solves the drawbacks of the prior art as described above, makes the substrate of the magnetoresistive element portion smaller, and makes it possible to improve mass productivity by manufacturing the magnetoresistive element on the integrated substrate. At the same time, it is possible to improve the arrangement accuracy of the magnetoresistive element, eliminate mutual magnetic interference between the encoder section and the position detection section, and further improve the recording track related to the magnetoresistive element and the magnetic material. The object of the present invention is to provide a magnetic rotation sensor that can be configured with as few as possible.

The features of the present invention include: a magnetic body attachment part that is attached to the rotating shaft of a brushless motor and has a magnetic substance on its surface; and a magnetoresistive element part that is disposed opposite to the magnetic body attachment part. A magnetic rotation sensor comprising: a detection track related to an encoder section configured to detect the number of rotations of a brushless motor, etc. on the magnetic body attachment section;
The magnetic rotation sensor is provided with a plurality of detection tracks related to a position detection section configured to detect the position of the motor.

For more details, please refer to the magnetic attachment part and the magnetoresistive element (
Hereinafter, this will be referred to as an MR element. ) section is divided into an encoder section and a position detection section, and the position detection section of the magnetic body attachment section is divided into sections corresponding to the number of phases of the brushless motor, and the magnetic recording direction of each detection track is made different. Furthermore, by arranging the MR element so as to face the detection track related to the magnetic material almost in a straight line, magnetic interference between the encoder section and the position detection section can be eliminated, and MR on the small tooth substrate can be realized. The structure of the magnetic rotation sensor is such that the elements can be arranged.

Next, each embodiment according to the present invention will be described based on the drawings.

First, FIG. 3 is an enlarged explanatory diagram of the related configuration of the magnetic body attachment part and the MR element part in one embodiment of the present invention.

The present embodiment relates to a three-phase, four-pole brushless motor.

In the figure, numeral 4 indicates a magnetic material, which is similarly provided on the desk 3 of the previous disc body to constitute a magnetic material attachment part D (hereinafter referred to as desk D). Detection track related to the encoder section, 41°42.43 is related to the position detection section, detection track divided into three sections, 6 is the MR element section, 6
0 is an MR element related to the encoder section, and 61 to 63 are MR elements related to the position detection section.

That is, magnetic signals N and '8 are sequentially recorded in the circumferential direction of the disk on the detection track 40 related to the encoder section located outside the desk D, and the magnetic signals N and '8 are recorded in three sections on the inside position detection section. The first detection track 41 for the first phase is divided into four parts at 90 degrees each in the circumferential direction.
8. Magnetic signals radially inside and outside. Record N, inner second
The second detection track 42 is used for the second phase, and the magnetic signal arrives at a position shifted by 60 degrees (120 degrees in electrical angle) in the circumferential direction from the magnetic signals S and N of the first detection track 41. The magnetic signals N and S are recorded in the same manner as above so that the magnetic directions are reversed, and the third detection track 43 in the inner corridor is used for the third phase, and the magnetic signals of the second detection track 42 are recorded. The magnetic signals S and N' are recorded so that the direction of magnetization is opposite to that of the magnetic signal at a position shifted by 60 degrees (120 degrees in electrical angle) in the circumferential direction of N and S.

Each MR element of the MR element section 6 facing this is
Each of the above-mentioned detection tracks 40, 41, 4 is arranged on one substrate so as to be arranged in a substantially straight line in the radial direction and inward and outward.
2.43, and are arranged in the MR element 60 related to the encoder section and the MR elements 61, 62.63 for the first phase, second phase, and third phase related to the position detection section. This is what I did.

The arrangement and structure relationship shown in FIG. 3 is developed into a band shape for easy separation, and is shown in the enlarged development view of FIG. 4.

In the figure, Rho to R- indicate resistance, and the MR element 60 in the encoder section is an element related to the resistance R0, and is used for the first phase, second phase, and third phase of the position detection section. M ordinary element 6
1, 62, and 63 are two sets of resistors R+ and FL, respectively.
It is composed of s, Rs, R4, Rji, and R-.

In the MR element 60 of the encoder section, the output of the encoder can be obtained by amplifying the resistance change of the resistor R0 as it is.

Moreover, each resistance of each MR element 61 to 63 of the position detection section is
As shown in the connection diagram of the MR element of the position detection section in Fig. 5,
Resistances R8 and R4 in the M1 elements 61 and 62 for the first and second phases, resistances Rs and R6 in the MR elements 62 and 63 for the second and third phases, M for 1st phase
The R element 63 and the resistors R and R in the R element 61 are connected in series to the power supply E, and the respective intermediate terminals ae
b.

It is designed so that three outputs can be obtained from C.

However, as mentioned earlier, the MR element is made of a thin film of ferromagnetic material, and when a magnetic field is applied in a direction perpendicular to the longitudinal direction, its resistance value decreases, and its characteristics against the magnetic field are As shown in Figure 6, which shows the characteristics of resistance change depending on the magnetic field of the MR element, the resistance R decreases due to the H or -H magnetic field, and the resistance change is saturated at a certain magnetic field. Furthermore, there is no change in resistance in a longitudinal magnetic field.

Therefore, in the arrangement as shown in FIG. 4 mentioned earlier, that is, in the arrangement in which each MR element records magnetic signals and its magnetic fields are perpendicular to each other in the longitudinal direction, the resistance change of each MR element is With the rotation of , the voltage v at the intermediate terminals a and c in FIG. 5 becomes as shown in (a) to (c) of FIG.

Vb, V. If the resistance of each MR element is made the same,
As shown in Fig. 7) to (f), the voltage changes around half the voltage of the previous power supply E, and furthermore, the differential voltage V a b N with the intermediate terminal afb of Fig. 5 ST C
Differential voltage Vb-0 between the same terminal and Vb-0. -1
are as shown in (g) to (man) in Fig. 7.

These voltages are processed by an amplifier or a comparator CM-U as exemplified in the signal processing circuit of FIG.

When waveform shaping is performed through CM-V and CM-W, a three-phase square wave is obtained from the terminals U, V, and W.

It can be used as a position signal for Gra/less motors.

Furthermore, with the above, it is possible to configure a bridge with the minimum number of MR elements.

As described above, according to the above embodiment, only two MR elements for each phase in the position detection part and one MR element in the encoder part are used, and the number of detection tracks in the desk related to the magnetic body attachment part is adjusted to the number of phases. This device can be configured with only one detection track for the encoder, and the number of detection tracks can be minimized.Furthermore, since the MR elements in the MR element section can be arranged in a straight line, it can be made compact, and - Since they can be assembled on a substrate to form a complete product, productivity is high, mass production is possible, and costs can be reduced.

In addition, the directions of magnetic signal recording in the encoder section and position detection section are arranged orthogonally, such as sequentially arranging in the circumferential direction and arranging inward and outward in the radial direction, thereby preventing mutual interference between magnetic signal recordings. Can be eliminated and also position inspection! Since the magnetic signal recording N and Sk of each detection track in the B section are arranged so that each detection track is in the opposite direction, magnetic interference between the detection tracks is also reduced.

Furthermore, since the number of MR elements is small, the wiring of the MR elements can be reduced, resulting in further miniaturization.Also, since the MR elements are small and can be fabricated on an integrated substrate by vapor deposition, etc., each MR element can be
There is no need to separately attach the R elements, and the accuracy of the attachment can be improved.

Next, FIG. 9 is a schematic configuration diagram showing a magnetic rotation sensor using a brushless motor, an MR element part, and a magnetic body attachment part having a magnetic body on the drum, according to another embodiment. be.

In the figure, 4-1 indicates a magnetic body, which is provided on a cylindrical drum to form a magnetic body attaching portion DM (hereinafter referred to as drum DM).

), 40-1 is a detection track related to the encoder section, 41-1.42-1.43-1 is a detection track related to the position detection section, and these detection tracks are as follows: divided in the axial direction,
-1 is a mounting base, and 6-1 is an MR element section.

That is, this embodiment differs from the previous embodiment in that the previous desk D is configured to be related to the drum DM, and the detection track 41-1.4 related to the position detection section is
2-1.43-1 is divided into three parts in the axial direction.

The detection tracks 41-1.42-1.43-1 are for the 1st, 2. and 3rd phases, respectively, and the MR element section 6-1 facing these and the above-mentioned detection track 40-1. 1 is equivalent to that according to the previous embodiment, and each MR element is arranged at a certain gap on the circumference of the drum DM.

Including the configurations of each of these detection tracks, each M, R element, etc., and developing their detailed correspondence in a band shape, it is the same as that shown in FIG. This is the same mode as explained above, and the same effects can be expected.

In each of the above embodiments, a three-phase, four-pole brushless motor was described; The configuration of the detecting section can be changed depending on the number of poles and the number of phases, and the same effect can be achieved by doing so.

According to the present invention, the following effects can be expected by taking the above into account.

(1) The MR element can be made smaller and can be constructed from an integrated substrate, improving mass productivity and making it possible to manufacture it at low cost.

(2) Since the MR element can be integrated, it is possible to prevent a decrease in accuracy due to mounting errors, and the alignment work is simplified.

(3) We hope to provide a device that eliminates magnetic interference between the encoder section, the position detection section, and between the position detection sections and provides stable output at all times, depending on the recording mode of the magnetic signal of the detection track related to the position detection section. I can do it.

Based on the above, the present invention can be said to be an invention that has excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a conventional magnetic rotation sensor using a brushless motor, a magnetoresistive element part, and a magnetic body attachment part having a magnetic body on a desk, and FIG. FIG. 3 is an enlarged diagram illustrating the structure of the magnetic body attachment part and the magnetoresistive element part, and FIG. The configuration explanatory diagram, Figure 4, is an enlarged development diagram of the arrangement, Figure 5.
The figure is a connection diagram of the magnetoresistive element of the position detection section, FIG. 6 is a resistance change characteristic diagram of the magnetoresistive element in response to a magnetic field, and FIG. 7 is an explanatory diagram of the operation related to the connection of FIG. 8
The figure shows a signal processing circuit diagram, and FIG. 9 shows a magnetic rotation sensor according to another embodiment of the present invention, which uses a magnetoresistive element part and a drum magnetic body attachment part in a brushless motor. FIG. 2 is a schematic configuration diagram. 1... Brushless motor, 2... Rotating shaft, 3...
Desk, 4.4-1...Magnetic material, 40-43.40-
1.41-1.42-1.43-1...Detection track, 6°6-1...Magnetoresistive element section, 60-63.
... Magnetoresistive element, D, DM... Magnetic body attachment part. Figure 1 Figure 2 Figure j14 Figure 3 Figure 4 Figure 5 Figure 1 Figure 7 (S)vc-α

Claims (1)

[Scope of Claims] 1. A magnetic body attachment part that is attached to a rotating shaft of a brushless motor and has a magnetic substance on its surface, and a magnetoresistive element that is arranged opposite to this magnetic body attachment part. In a one-shot rotation sensor consisting of multiple parts, the magnetic body attachment part has a detection track related to an encoder part that detects the rotation speed of a brushless motor, and the position of the motor. 1. A magnetic rotation sensor comprising a track divided into a plurality of sections relating to a position detection section. 2. In the device described in claim 1, magnetic signals N and S are sequentially recorded in the circumferential direction on the detection track related to the encoder section, and the position detection is divided according to the number of phases of the brushless motor. A magnetic signal N, + 8 is applied to each detection track according to the motor, shifted in position based on the number of poles of the motor concerned.
A magnetic rotation sensor that records information in the radial direction, the outside direction, or the axial direction. 3. In the item described in claim 1, the magnetic attachment portion is connected to the encoder portion on the concentric circle of the disk body or in the axial direction of the cylinder body, and the magnetic signal N, 8
The magnetic signals N, 8 are divided into concentric circles or in the axial direction according to the number of phases of the brushless motor, and are shifted in position based on the number of poles of the motor to send magnetic signals N and 8 radially outward and outward. Alternatively, the detection track recorded in the axial direction may be divided into a disk or a drum, and facing each detection track of this disk or drum, the detection track recorded in the axial direction may be - A magnetoresistive sensor in which a magnetoresistive element section having a plurality of magnetoresistive elements is arranged, the encoder section and the position detection section being arranged in a straight line. 4. In the product described in claim 3, the attached brushless motor is three-phase, the detection circuit related to the position detection section is divided into three, and each magnetoresistive effect is arranged opposite to each of these. Two sets of elements are provided, with the magnetoresistive elements facing each of the first and second detection tracks, the second and third detection tracks, and the third and first detection tracks. Three brushless motors connected in series to the power supply and output from their respective intermediate terminals are connected to a three-phase, four-pole motor, and a detection track is connected to an encoder section located outside of the desk or drum where the LAil body is attached. , a magnetic signal N is applied sequentially in the local direction of the disc or cylinder. S is recorded, and the first detection track, which is divided into three according to the position detection section on the inner side, is used for the first phase and is moved 9 in the circumferential direction.
It is divided into four parts of 0 degree each, and magnetic signals S are applied to the two diagonal locations inside and outside in the radial direction, or in the axial direction. N is recorded, and the second inner detection track is used for the second phase, and the magnetic signals S and N of the first detection track are shifted in the circular direction (120 degrees in electrical angle). A magnetic signal N is generated so that the direction of magnetization is opposite to that of the magnetic signal.
. A magnetic rotation sensor that records magnetic signals S and N so that