JP2006084416A - Mobile body position detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire movement information (an phase A and a phase B) and home position information (a phase Z) without influence from various types of dispersion, and to carry out miniaturization and cost reduction of a bias magnet by rationalizing arrangement of the bias magnet. <P>SOLUTION: The mobile body position detector has a first soft magnetic rotor 1 having teeth 1a at certain intervals, a second soft magnetic rotor 2 integrally turning with the rotor 1 and having one cutout part 2a, a vector detecting type magnetoresistive element group 10 facing the rotor 1 to acquire the movement information, a vector detecting type magnetoresistive element group 20 facing the rotor 2 to acquire the home position information, and the bias magnet 15. The bias magnet 15 mainly has a magnetic field component in parallel with respective magnetic sensing planes of the vector detecting type magnetoresistive element groups 10 and 20 when there are no rotors 1 and 2, and it is arranged such that a magnetic flux is generated in perpendicular to each pin layer magnetization direction of the vector detecting type magnetoresistive element groups 10 and 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a detection device that detects a magnetic field change accompanying a relative movement with a magnetic material using a magnetoresistive effect element, and in particular, a relative movement between a soft magnetic material and a magnetoresistive effect element used in an industrial machine tool or the like. The present invention relates to a mobile body position detection apparatus suitable for use in obtaining information.

  The conventional moving body position detecting device, when obtaining rotation information, includes a first soft magnetic material rotating body 1 provided with a predetermined number of teeth (convex portions) 1a at a constant pitch on the circumference as shown in FIG. The second soft magnetic material rotating body 2 that rotates integrally with this and provided with a notch 2a at a part of the circumference is opposed to the first soft magnetic material rotating body 1 and 90 ° therefrom. A first magnetoresistance effect element 3 that obtains a phase difference 2 signal (A phase and B phase) and a second magnetoresistance that faces the second soft magnetic material rotating body 2 and obtains an origin signal (Z phase) therefrom. The effect element 4 is provided. Bias magnets 5 and 6 are arranged behind the first and second magnetoresistive elements 3 and 4, respectively. The magnetic pole directions of the bias magnets 5 and 6 are arranged so as to generate a magnetic field perpendicular to the outer peripheral surfaces of the rotating bodies 1 and 2. The magnetoresistive effect element used in the conventional apparatus of FIG. 12 is an intensity detection type magnetoresistive effect element.

A configuration similar to that of the above-described conventional apparatus is disclosed in Patent Document 1 below.
Japanese Patent Laid-Open No. 10-260061

  In the conventional moving body position detecting device, as shown in FIG. 12, behind the first magnetoresistive effect element for obtaining the 90 ° phase difference 2 signal and the second magnetoresistive effect element for obtaining the origin signal, respectively. It is necessary to arrange bias magnets one by one, or a large magnet behind each of the first and second magnetoresistive elements. Therefore, the sensor shape becomes large and the cost also increases.

  In addition, since the intensity detection type magnetoresistive effect element is used, the rate of change in resistance depends on the strength of the external magnetic field. Therefore, (1) variation in resistance value of magnetoresistive effect element, (2) variation in sensitivity (resistance change rate) of magnetoresistive effect element, (3) variation in magnetic field intensity generated by bias magnet, (4) rotating body of soft magnetic material -There is a problem that the detected output waveform fluctuates due to variations in the gap between magnetoresistive elements.

  In view of the above points, the present invention uses a vector detection type magnetoresistive effect element as a magnetoresistive effect element to obtain movement information (A phase and B phase) without being affected by various variations. Necessary signals can be obtained from the resistive element and the vector detection type magnetoresistive element that obtains origin information (Z-phase), and the arrangement of the bias magnet is streamlined to reduce the size and cost of the bias magnet. It is an object of the present invention to provide a movable body position detecting device.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, a first moving body position detection device according to the present invention includes a first magnetic material having convex portions or concave portions at a constant interval, and a fixed position with respect to the first magnetic material. A second magnetic material having at least one convex portion or concave portion that maintains the relationship; a first vector detection type magnetoresistive effect element that obtains movement information opposite to the first magnetic material; and the second magnetic material. A second vector detection type magnetoresistive element that obtains origin information opposite to the material; and a bias magnet that generates a magnetic field; and the first and second magnetic materials and the first and second vectors. It is configured to detect a relative position with a sensing type magnetoresistive element,
The bias magnet mainly has a magnetic field component parallel to the magnetic sensitive surface of each of the first and second vector sensing magnetoresistive elements when the first and second magnetic materials are not present, and Each vector detection type magnetoresistive effect element is arranged so as to generate a magnetic flux substantially perpendicular to the pinned layer magnetization direction.

The second moving body position detecting apparatus according to the present invention includes a magnetic material having a first portion having a convex portion or a concave portion at a constant interval and a second portion having at least one convex portion or a concave portion, and the first portion. A first vector detection type magnetoresistive effect element that obtains movement information opposite to the first part, a second vector detection type magnetoresistive effect element that obtains origin information opposite to the second part, and a bias magnet that generates a magnetic field And detecting the relative position of the magnetic material having the first part and the second part and the first and second vector sensing magnetoresistive elements,
The bias magnet mainly has a magnetic field component parallel to the magnetic sensitive surface of each of the first and second vector detection type magnetoresistive effect elements when there is no magnetic material having the first part and the second part. In addition, each vector detection type magnetoresistive effect element is arranged so as to generate a magnetic flux substantially perpendicular to the pinned layer magnetization direction.

  In the moving body position detecting device, the bias magnet may be configured such that the first vector detection type magnetoresistive resistor is perpendicular to a direction of relative movement with the magnetic material and parallel to a surface having a convex portion or a concave portion of the magnetic material. It is preferable that at least one effect element is disposed between the effect element and the second vector detection type magnetoresistive effect element.

  The moving body position detecting device may be configured such that a soft magnetic material is added to the bias magnet.

  A detection output waveform of the movement information by the first vector detection type magnetoresistive effect element may be a substantially sine wave.

  The vector detection type magnetoresistance effect element may be a spin valve type giant magnetoresistance effect element.

  According to the moving body position detecting device of the present invention, a vector detection type magnetoresistive effect element is used as a magnetoresistive effect element for obtaining movement information (A phase and B phase) and origin information (Z phase), and the relative moving magnetism. A bias magnet is used so that when there is no material, the magnetic field component is mainly parallel to the magnetic sensitive surface of each vector detection type magnetoresistive effect element, and magnetic flux is generated substantially perpendicular to the magnetization direction of the pinned layer. Arrangement of desired movement information and origin information without being affected by various variations (variation in sensitivity of magnetoresistive effect element, variation in magnetic field strength of bias magnet, variation in gap between magnetic material and magnetoresistive effect element, etc.) The detection signal can be obtained.

  Further, the arrangement of bias magnets for applying a bias magnetic field to the vector detection type magnetoresistive effect element for obtaining movement information (A phase and B phase) and the vector detection type magnetoresistive effect element for obtaining origin information (Z phase) has been rationalized. Thus, the bias magnet can be reduced in size, and the overall shape can be reduced, and the cost can be reduced.

  Hereinafter, as a best mode for carrying out the present invention, an embodiment of a moving body position detecting device will be described with reference to the drawings.

  FIG. 1 is a first embodiment of a moving body position detecting apparatus according to the present invention, in which a rotation sensor for obtaining movement (rotation) information and origin information of a soft magnetic material rotating body is configured as a soft magnetic material moving body. Show the case.

  In FIG. 1A, the first soft magnetic material rotating body 1 has a configuration in which a predetermined number of teeth (convex portions) 1a are provided at a circumferentially arranged outer peripheral surface at a constant pitch P. The second soft magnetic material rotating body 2 that maintains a fixed positional relationship (rotates integrally) has a configuration in which a notch 2a is provided on a part of the outer peripheral surface that is a circumference.

  A first spin-valve giant magnetoresistive element as a first magnetoresistive effect element facing the first soft magnetic material rotating body 1 and obtaining two 90 ° phase difference signals (A phase and B phase) therefrom A group 10 (hereinafter referred to as an SV-GMR element) is arranged. Further, a second SV-GMR element group 20 is arranged as a second magnetoresistive effect element facing the second soft magnetic material rotating body 2 and obtaining an origin signal (Z phase) therefrom. In addition, one bias magnet 15 is arranged to apply a bias magnetic field to the first and second SV-GMR element groups 10 and 20.

  Here, as shown in FIG. 1B, two pairs of SV-GMR elements R1 to R4 are used as the first SV-GMR element group 10, and one pair of SV-GMR element groups 20 is used. -GMR elements R5 and R6 are used. In FIG. 1, SV-GMR 1 to 6 are illustrated larger than the bias magnet 15 for easy understanding, but in actuality, the dimensions are small.

  Two pairs of SV-GMR elements R1 to R4 as the first SV-GMR element group 10 are opposed to the outer peripheral surface of the first soft magnetic material rotating body 1, and one of the SV-GMR elements R1 and R2 is a pair. Are on the same plane (a surface parallel to the moving direction of the rotating body 1) opposite to the outer peripheral surface, and are substantially perpendicular to the moving direction of the rotating body 1 and the thickness direction of the rotating body 1 (that is, having a convex portion). In a direction parallel to the surface). The pinned layer magnetization directions of the SV-GMR elements R <b> 1 and R <b> 2 are arranged so as to be substantially forward and substantially opposite to the moving direction of the rotating body 1.

The other pair of SV-GMR elements R3 and R4 is also on the same plane (a plane parallel to the moving direction of the rotating body 1) facing the outer peripheral surface of the rotating body 1 and is substantially perpendicular to the moving direction of the rotating body 1 They are arranged in the thickness direction of the rotating body 1, and are located at a distance of the arrangement interval L in the moving direction of the rotating body 1 from the pair of SV-GMR elements R 1 and R 2. However, the arrangement interval L is P when the arrangement pitch of the teeth 1a of the rotating body 1 is P.
L = nP ± P / 4 (n is an integer) (1)
It is. The pinned layer magnetization directions of the SV-GMR elements R3 and R4 are also arranged so as to be substantially forward and substantially opposite to the moving direction of the rotating body 1, respectively.

  The pair of SV-GMR elements R5 and R6 as the second SV-GMR element group 20 are on the same plane facing the outer peripheral surface of the second soft magnetic material rotating body 2 (surface parallel to the moving direction of the rotating body 2). They are arranged in a direction substantially perpendicular to the moving direction of the rotating body 2 (in the thickness direction of the rotating body 2). The pinned layer magnetization directions of the SV-GMR elements R5 and R6 are arranged so as to be substantially forward and substantially opposite to the moving direction of the rotating body 2, respectively.

  A bias magnet 15 for generating a bias magnetic field includes a first SV-GMR element group 10 (two pairs of SV-GMR elements) in a thickness direction perpendicular to the moving direction of the first and second soft magnetic material rotating bodies 1 and 2. R1 to R4) and one SV-GMR element group 20 (a pair of SV-GMR elements R5 and R6). When the first and second rotating bodies 1 and 2 do not exist, the magnetic field at the position of the SV-GMR elements R1 to R6 mainly has a magnetic field component parallel to the magnetosensitive surface of the SV-GMR elements R1 to R6. And a magnetic pole arrangement that generates a magnetic flux substantially perpendicular to the pinned layer magnetization direction of each of the SV-GMR elements R1 to R6 (for example, the magnetic pole surface 15a is substantially perpendicular to the magnetosensitive surface). The side surface 15b of the bias magnet 15 is flush with the magnetosensitive surface so that the bias magnet 15 does not protrude into the gap between the magnetosensitive surfaces of the SV-GMR elements R1 to R6 and the outer peripheral surfaces of the rotating bodies 1 and 2. It is in the upper or slightly retracted position.

  As shown in FIG. 2A, the supply voltage Vin is supplied to the series connection of the paired SV-GMR elements R1 and R2 and the series connection of the paired SV-GMR elements R3 and R4. A voltage between the connection point of R1 and R2 and the ground (GND) is obtained as an A-phase detection output of FIG. 2B, and a voltage between the connection point of SV-GMR elements R3 and R4 and the ground is B phase ( (The operation principle will be described in FIG. 4 and FIG. 5 below.).

  Further, as shown in FIG. 3A, the supply voltage Vin is supplied to the series connection of the paired SV-GMR elements R5 and R6, and the voltage between the connection point of the SV-GMR elements R5 and R6 and the ground is It can be obtained as the Z-phase detection output in FIG. 3B (the operation principle will be described with reference to FIGS. 4 and 5 below).

  The SV-GMR element is composed of a pinned layer whose magnetization direction is fixed in one direction, a nonmagnetic layer through which a current mainly flows, and a free layer whose magnetization direction matches the external magnetic field direction (external magnetic flux direction). . When the pin layer magnetization direction matches the external magnetic field vector direction, the resistance value is low. When the external magnetic field vector direction is rotated in the SV-GMR element plane, the resistance value changes depending on the angle formed with the pin layer magnetization direction. In the opposite direction, the resistance value is high. This characteristic is the in-plane magnetic characteristic of the SV-GMR element shown in FIG. 4, and the rotation center perpendicular to the magnetosensitive surface is obtained under the condition that an external magnetic field parallel to the magnetosensitive surface of the SV-GMR element exists. It shows the relationship between the rotation angle with respect to the pinned layer magnetization direction and the rate of change in resistance (ΔR / R). In this case, the rate of change in resistance (ΔR / R) changes gently with a waveform close to a sine wave, and no saturation region occurs.

  In this embodiment, the in-plane magnetic characteristics of the SV-GMR element shown in FIG. 4 are used. That is, the external magnetic field is changed under the condition that a bias magnetic field is applied by a bias magnet parallel to the magnetic sensing surface of the SV-GMR element as shown in FIG. By utilizing the in-plane magnetic characteristics that change with time, an output waveform of a substantially sine wave (without a saturation region) in FIG.

  Therefore, in the arrangement of the present embodiment shown in FIGS. 1A and 1B, the teeth 1a of the first soft magnetic material rotating body 1 provided for obtaining the movement information are the pairs of the SV-GMR elements R1 and R2. The direction of the magnetic field component parallel to the magnetic sensitive surface of each SV-GMR element R1, R2 is not affected by the tooth 1a and is substantially perpendicular to the pinned layer magnetization direction. On the other hand, when the tooth 1a of the rotating body 1 is shifted to the left side from the front position of the SV-GMR elements R1 and R2, the direction of the magnetic field component parallel to the magnetosensitive surface is bent to the left side due to the influence of the tooth 1a. (The magnetic flux emitted from the magnetic pole surface 15a bends to the left). Further, when the tooth 1a of the rotating body 1 is shifted to the right side from the front position of the SV-GMR elements R1 and R2, the direction of the magnetic field component parallel to the magnetosensitive surface is bent to the right side due to the influence of the convex portion 2. (The magnetic flux emitted from the magnetic pole surface 15a bends to the right). Accordingly, the direction of the external magnetic field with respect to the pinned layer magnetization direction periodically changes with the rotation of the rotating body 1 within the operation range indicated by the solid line arrow in FIG. 5B, and a substantially sine wave detection output as shown in FIG. Is obtained.

  This also applies to the pair of SV-GMR elements R3 and R4, and the arrangement interval L between the pair of SV-GMR elements R1 and R2 and the pair of SV-GMR elements R3 and R4 for obtaining movement information is the same. Due to the relationship of the expression (1), a substantially sine wave voltage waveform of the A phase and the B phase having a phase difference of 90 ° shown in FIG. 2B is obtained.

  Further, when the pair of SV-GMR elements R5 and R6 is not opposed to the notch 2a of the second soft magnetic material rotating body 2 provided for obtaining the origin information, each of the SV-GMR elements R5 and R6 The direction of the magnetic field component parallel to the magnetosensitive surface is not affected by the notch 2a and is substantially perpendicular to the pinned layer magnetization direction. On the other hand, at the position where the edge of the notch 2a of the rotating body 2 is close to the left side of the SV-GMR elements R5 and R6, the direction of the magnetic field component parallel to the magnetosensitive surface is affected by the edge of the notch 2a. Turns to the left (the magnetic flux from the magnetic pole surface 15a turns to the left). Further, at the position where the edge of the notch 2a of the rotating body 2 is close to the right side of the SV-GMR elements R5 and R6, the direction of the magnetic field component parallel to the magnetosensitive surface is bent to the right by the influence of the convex part 2. (The magnetic flux emitted from the magnetic pole surface 15a bends to the right). Accordingly, the external magnetic field direction with respect to the pinned layer magnetization direction changes periodically once with the rotation of the rotating body 2 within the operation range indicated by the solid line arrow in FIG. 5B, and a substantially sine wave as shown in FIG. The Z-phase detection output is obtained.

  According to the first embodiment, the following effects can be obtained.

(1) SV-GMR element group 10 (R1 to R4) as a first vector detection type magnetoresistive effect element that obtains movement information facing the first soft magnetic material rotating body 1, and the second soft magnetic material rotation One bias magnetic field generating bias magnet 15 is commonly used for the SV-GMR element group 20 (R5, R6) as the second vector detection type magnetoresistive effect element that obtains origin information facing the body 2. Therefore, since a necessary detection output signal can be obtained from the SV-GMR element group 10 that detects movement information (A phase and B phase) and the SV-GMR element group 20 that detects origin information (Z phase), The size can be reduced, and the cost can be reduced.

(2) The bias magnet 15 is placed in the first SV-GMR element group 10 and the second SV-GMR element group 20 in the thickness direction perpendicular to the moving direction of the first and second soft magnetic material rotating bodies 1 and 2. Between each of the SV-GMR elements when the first and second rotating bodies 1 and 2 are not present, and each SV-GMR element mainly has a magnetic field component parallel to the magnetosensitive surface. A magnetic flux substantially perpendicular to the pinned layer magnetization direction of the GMR element can be generated. For this reason, arrangement | positioning of the bias magnet 15 can be rationalized and it can contribute to the further size reduction.

(3) An SV-GMR element is used as a vector detection type magnetoresistive effect element. Compared with a conventional device using a strength detection type magnetoresistive effect element, the magnetic field intensity variation of the bias magnet and softness are reduced. Since it is not influenced by the gap (assembly variation) between the magnetic material rotating body and the magnetoresistive effect element, it is possible to stabilize the detection output signal.

(4) Apply a bias magnetic field parallel to the magnetosensitive surface of the SV-GMR element as shown in FIG. 5A to utilize the in-plane magnetic characteristics, and the operating range is pinned as shown in FIG. 5B. Detection of the A phase and the B phase in order to use a portion where the angle of both changes around the point where the magnetization direction of the layer and the magnetic field are substantially orthogonal (to utilize the linear portion of the in-plane magnetic property change of the SV-GMR element). A waveform very close to a sine wave without saturation can be obtained as an output.

(5) The pair of SV-GMR elements R1 and R2, the pair of SV-GMR elements R3 and R4, and the pair of SV-GMR elements R5 and R6 are such that the pin layer magnetization direction is the moving direction of the soft magnetic material rotating bodies 1 and 2. On the other hand, since each of the SV-GMR elements is connected in series with each other, the supply voltage Vin is supplied and the detection output is taken out from the connection point between the SV-GMR elements. Thus, a detection output twice as large as that when one SV-GMR element is used can be obtained.

  FIG. 6 is a second embodiment of the present invention, in which an SV-GMR element group 10 as a first vector detection type magnetoresistive effect element for obtaining movement information (A phase, B phase) and origin information (Z phase) 2) shows a configuration in which an SV-GMR element group 20 as a second vector detection type magnetoresistive effect element and a bias magnetic field generating bias magnet 15 are mounted on a substrate 30. The SV-GMR element group 10 and the SV-GMR element group 20 are attached to one surface of the substrate 30, and the bias magnetic field generating bias magnet 15 is attached to the other surface of the substrate 30. When the SV-GMR element group 10 and the SV-GMR element group 20 are opposed to the first and second soft magnetic material rotating bodies as shown in FIG. It is located between the first SV-GMR element group 10 and the second SV-GMR element group 20 in the thickness direction perpendicular to the moving direction of the magnetic material rotating body.

  In the second embodiment, since each SV-GMR element is actually a small size, the magnetic flux emitted from the magnetic pole surface 15a of the bias magnet 15 passes substantially parallel to the magnetic sensitive surface of each SV-GMR element. (It can be set so as to mainly have a magnetic field component parallel to the magnetosensitive surface).

  In the case of the second embodiment, by using the substrate 30, other components such as an amplifier circuit can be mounted together. Other configurations and operations of the second embodiment are the same as those of the first embodiment.

  FIG. 7 shows a third embodiment of the present invention, in which an SV-GMR element group 10 for obtaining movement information (A phase and B phase), an SV-GMR element group 20 for obtaining origin information (Z phase), and a bias magnetic field. A configuration in which the generating bias magnet 15 is mounted on the substrate 30 is shown in which the length of the bias magnet 15 is changed. In this case, the SV-GMR element group 10 and the SV-GMR element group 20 are attached to one surface of the substrate 30, and the bias magnet 15 is attached to the other surface of the substrate 30. The bias magnet 15 is provided so as to overlap the back surfaces of both the SV-GMR element group 10 and the SV-GMR element group 20.

  In the third embodiment, a magnetic field component parallel to the magnetosensitive surface of each SV-GMR element is mainly applied by utilizing the fact that the magnetic flux passes substantially parallel along the side surface between the magnetic poles of the bias magnet 15. It can be set as follows. Further, by using the substrate 30, other components such as an amplifier circuit can be mounted together.

  Other configurations and operations of the third embodiment are the same as those of the first embodiment.

  FIG. 8 is a fourth embodiment of the present invention, and is provided between the SV-GMR element group 10 that obtains movement information (A phase and B phase) and the SV-GMR element group 20 that obtains origin information (Z phase). Instead of arranging the bias magnetic field generating bias magnet 15, the bias magnetic field generating bias magnet 15 is arranged at an extended line position in the arrangement direction of the SV-GMR element group 10 and the SV-GMR element group 20.

  In the fourth embodiment, a magnetic flux perpendicularly emitted from the magnetic pole surface 15a of the bias magnet 15 passes substantially linearly along the arrangement direction of the SV-GMR element group 10 and the SV-GMR element group 20, whereby each SV. -It can be set so as to mainly have a magnetic field component parallel to the magnetosensitive surface of the GMR element.

  In the fourth embodiment, the first and second soft magnetic material rotating bodies on which the SV-GMR element group 10 and the SV-GMR element group 20 are opposed to each other are thin, and the SV-GMR element group 10 and the SV-GMR This structure is particularly suitable when it is difficult to dispose the bias magnet 15 between the element groups 20.

  Other configurations and operations of the fourth embodiment are the same as those of the first embodiment.

  FIG. 9 shows a fifth embodiment of the present invention in which a configuration substantially similar to that of FIG. 8 is realized using a substrate. In this case, the SV-GMR element group 10 that obtains movement information (A phase, B phase) and the SV-GMR element group 20 that obtains origin information (Z phase) are attached to one surface of the substrate 30, and the bias magnet 15 Is attached to the other surface of the substrate 30. The bias magnet 15 is disposed at a substantially extended line position in the arrangement direction of the SV-GMR element group 10 and the SV-GMR element group 20.

  In the fifth embodiment, since each SV-GMR element is actually a small size, the magnetic fluxes perpendicularly emitted from the magnetic pole surface 15a of the bias magnet 15 are almost linearly aligned with the SV-GMR element group 10 and the SV-GMR. By passing along the arrangement direction of the element group 20, it can be set so as to mainly have a magnetic field component parallel to the magnetic sensitive surface of each SV-GMR element.

  In the fifth embodiment, the first and second soft magnetic material rotating bodies on which the SV-GMR element group 10 and the SV-GMR element group 20 are opposed to each other are thin, and the SV-GMR element group 10 and the SV-GMR This structure is particularly suitable when it is difficult to dispose the bias magnet 15 between the element groups 20. Further, by using the substrate 30, other components such as an amplifier circuit can be mounted together.

  Other configurations and operations of the fifth embodiment are the same as those of the first embodiment.

  FIG. 10 shows a sixth embodiment of the present invention, in which an SV-GMR element group 10 that obtains movement information (A phase and B phase), an SV-GMR element group 20 that obtains origin information (Z phase), and a bias magnetic field. A configuration in which the generating bias magnet 15 is mounted on the substrate 30 is shown in which the length and arrangement of the bias magnet 15 are changed. In this case, the SV-GMR element group 10 and the SV-GMR element group 20 are attached to one surface of the substrate 30, and the bias magnet 15 is attached to the other surface of the substrate 30. The bias magnet 15 is provided so as to overlap the back surface of one SV-GMR element group 10, and one magnetic pole surface of the bias magnet 15 is disposed close to the SV-GMR element group 20.

  As in the sixth embodiment, by arranging the bias magnet 15 so as to overlap one of the back surfaces of the SV-GMR element, the magnetic flux passes substantially parallel along the side surface between the magnetic poles of the bias magnet 15. It can be set so that a magnetic field component parallel to the magnetosensitive surface of one SV-GMR element group 10 is mainly applied, and the magnetic flux passes substantially perpendicular to the magnetic pole surface in the vicinity of the magnetic pole surface. Can be set so that a magnetic field component parallel to the magnetosensitive surface of the other SV-GMR element group 20 is mainly applied. Further, by using the substrate 30, other components such as an amplifier circuit can be mounted together.

  Other configurations and operations of the sixth embodiment are the same as those of the first embodiment.

  FIG. 11 shows a seventh embodiment of the present invention, in which an SV-GMR element group 10 for obtaining movement information (A phase, B phase) and an SV-GMR element group 20 for obtaining origin information (Z phase) are shown. A bias magnet 15 for generating a bias magnetic field is disposed, and soft magnetic bodies 16 are provided on the magnetic pole surfaces at both ends thereof.

  In the seventh embodiment, by adding the soft magnetic body 16, the bias magnetic field can be made uniform and stabilized. Further, even if the bias magnet 15 is small, by providing the soft magnetic bodies 16 on the magnetic pole surfaces at both ends, the distance from the SV-GMR element groups 10 and 20 can be reduced, and the magnetic sensitivity of each SV-GMR element can be reduced. It can be set so as to mainly have a magnetic field component parallel to the surface.

  Other configurations and operations of the seventh embodiment are the same as those of the first embodiment.

  In each of the above embodiments, one bias magnet 15 is used. However, a combination structure of permanent magnets (that is, a combination structure of a plurality of bias magnets) obtained by dividing the bias magnet 15 into a plurality of parts may be used.

  Further, in each of the above embodiments, the first soft magnetic material rotating body 1 provided with a predetermined number of teeth at a constant interval pitch, and the second soft magnetic material provided with a notch in a part rotating integrally therewith. Although the material rotating body 2 is used, both rotating bodies may be formed in advance as an integrated product. That is, it is possible to use a soft magnetic rotating body having a first portion provided with a predetermined number of teeth at a constant interval pitch and a second portion provided with a notch portion in part.

  Furthermore, instead of the first and second soft magnetic material rotating bodies, a half provided with a first portion or member having convex portions or concave portions at a constant interval and a second portion or member having at least one convex portion or concave portion. It is also possible to use a soft magnetic material rotating body having a curved surface such as a circumference or a soft magnetic material linear moving body having a flat surface.

  Further, the SV-GMR element for obtaining movement information (A phase, B phase), the SV-GMR element for obtaining origin information (Z phase), and the bias magnet are not limited to the fixed arrangement, and are relatively moved with respect to the soft magnetic material. It is apparent that the present invention can be applied to any configuration that does this.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a first embodiment of a moving body position detecting apparatus according to the present invention, where (A) is a perspective view of the overall configuration showing the arrangement of a soft magnetic material rotating body, an SV-GMR element, and a bias magnet; It is a principal part perspective view which shows arrangement | positioning of the SV-GMR element which acquires information (A phase, B phase), the SV-GMR element which acquires origin information (Z phase), and a bias magnet. In the first embodiment, (A) is a circuit diagram for extracting output signals of A phase and B phase whose phases are shifted by 90 °, and (B) is a waveform diagram of output signals of A phase and B phase. In Embodiment 1, (A) is a circuit diagram for extracting a Z-phase output signal, and (B) is a waveform diagram of the Z-phase output signal. FIG. It is explanatory drawing which shows the in-plane magnetic characteristic of the SV-GMR element used by this invention. FIG. 4 is an explanation of the operation of the SV-GMR element according to the present invention, where (A) is a perspective view showing the relationship between the bias magnetic field and the magnetosensitive surface of the SV-GMR element and the pinned layer magnetization direction, and (B) is the SV-GMR element. FIG. 5C is an explanatory diagram showing an in-plane magnetic characteristic and an operating range, and FIG. It is a principal part perspective view of Embodiment 2 of this invention. It is a principal part perspective view of Embodiment 3 of this invention. It is a principal part perspective view of Embodiment 4 of this invention. It is a principal part perspective view of Embodiment 5 of this invention. It is a principal part perspective view of Embodiment 6 of this invention. It is a principal part perspective view of Embodiment 7 of this invention. It is a perspective view of the conventional mobile body position detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st soft-magnetic material rotating body 1a tooth | gear 2 2nd soft-magnetic material rotating body 2a Notch part 3, 4 Magnetoresistive effect element 5, 6, 15 Bias magnet 10,20 SV-GMR element group 15a Magnetic pole surface 15b Side surface 30 Substrate R1-R6 SV-GMR element

Claims (6)

A first magnetic material having convex portions or concave portions at regular intervals; a second magnetic material having at least one convex portion or concave portion that maintains a fixed positional relationship with respect to the first magnetic material; and A first vector detection type magnetoresistive effect element that obtains movement information opposite to the magnetic material, a second vector detection type magnetoresistive effect element that obtains origin information opposite to the second magnetic material, and a magnetic field. A movable body position detecting device for detecting a relative position between the first and second magnetic materials and the first and second vector sensing type magnetoresistive effect elements,
The bias magnet mainly has a magnetic field component parallel to the magnetic sensitive surface of each of the first and second vector sensing magnetoresistive elements when the first and second magnetic materials are not present, and A moving body position detecting apparatus, wherein the vector detecting type magnetoresistive effect element is arranged so that a magnetic flux is generated substantially perpendicularly to a pinned layer magnetization direction. A magnetic material having a first part having a convex part or a concave part and a second part having at least one convex part or a concave part at a constant interval, and a first vector detection type for obtaining movement information facing the first part A magnetoresistive effect element; a second vector detection type magnetoresistive effect element that obtains origin information opposite to the second part; and a bias magnet that generates a magnetic field, wherein the first part and the second part are A moving body position detecting device for detecting a relative position between a magnetic material having the first magnetic detecting element and the second and second vector detecting magnetoresistive elements,
The bias magnet mainly has a magnetic field component parallel to the magnetic sensitive surface of each of the first and second vector detection type magnetoresistive effect elements when there is no magnetic material having the first part and the second part. And a moving body position detecting device, wherein the vector detecting type magnetoresistive effect element is arranged so as to generate a magnetic flux substantially perpendicularly to the pinned layer magnetization direction.   The bias magnet includes the first vector detection type magnetoresistive element and the second vector in a direction perpendicular to a direction of relative movement with the magnetic material and parallel to a surface having a convex portion or a concave portion of the magnetic material. The moving body position detecting device according to claim 1 or 2, wherein at least one moving body position detecting device is arranged between the detecting type magnetoresistive effect elements.   4. The moving body position detecting device according to claim 1, wherein a soft magnetic material is added to the bias magnet.   5. The moving body position detecting device according to claim 1, wherein a detection output waveform of the movement information by the first vector detection type magnetoresistive effect element is a substantially sine wave.   6. The moving body position detecting device according to claim 1, wherein the vector detection type magnetoresistive effect element is a spin valve type giant magnetoresistive effect element.

Images