JP2011112471A - Magnetic encoder and rotation detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder and a rotation detecting apparatus capable of being simply magnetized without generating magnetic interference, improving magnetization accuracy, and reducing manufacturing costs, in a double-row magnetic encoder track. <P>SOLUTION: The magnetic encoder 1 includes: the annular magnetic encoder tracks 3 and 4 which are double in row and adjacent to each other; and a core metal 2. Detection surfaces 3a and 4a of the respective magnetic encoder tracks 3 and 4 double in row are disposed oblique to an axial direction L1 when a cross section cut by a plane containing the axial direction L1 of the magnetic encoder 1 is viewed. The core metal 2 has an L-shape when a cross section cut by a plane containing the axial direction L1 of the magnetic encoder 1. A cylinder-like inner circumferential surface 7 is press-fitted on an outer peripheral surface 8a of an attaching object 8 comprising a rotary member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic encoder and a rotation detection device used for rotation detection and rotation angle detection of various devices.

With respect to the technical field of bearing elements, techniques for obtaining interpolated pulse signals using magnetic sensors arranged in a line are disclosed (Patent Documents 1 and 2).
A technique for calculating an absolute angle using a magnetic drum having a different number of magnetic pole pairs per rotation and a plurality of magnetic sensors is disclosed (Patent Document 3).
An angle detection device that detects an absolute angle based on the phase difference between two different magnetic encoders using the magnetic sensor in Patent Documents 1 and 2 is disclosed (Patent Document 4).

JP-T-2001-518608 Special Table 2002-541485 JP-A-6-58766 JP 2008-233069 A

In the angle detection device of Patent Document 4 to which Patent Documents 1 and 2 are applied, when the sensor element and the arithmetic processing circuit are integrated on a semiconductor, it is desired to arrange the sensor in the smallest possible space.
If the two magnetic encoders used in Patent Document 3 are arranged close to each other, the magnetic patterns interfere with each other, and the angle detection accuracy deteriorates. As a result, the phase difference for calculating the absolute angle cannot be obtained accurately, and the error for calculating the absolute angle increases.

When the magnetic encoder described in Patent Document 4 is realized with a different configuration, if deformation occurs during the assembly process of the magnetic encoder, the magnetization accuracy deteriorates. In particular, when the magnetic encoder is assembled after magnetization, the influence is great.
Further, since it is difficult to match the signals magnetized to the respective magnetic encoders, it is necessary to set a phase adjustment step and a phase shift correction value in the absolute angle detection arithmetic circuit.
Although the above-described problem can be solved by configuring a plurality of sensor element intervals to be large, the semiconductor chip area increases and the manufacturing cost increases.

  An object of the present invention is to provide a magnetic encoder and a rotation detection device capable of easily magnetizing a double-row magnetic encoder track without causing magnetic interference, improving the magnetization accuracy, and reducing the manufacturing cost. Is to provide.

  The magnetic encoder of the present invention is a magnetic encoder having adjacent double-row annular magnetic encoder tracks, wherein the detection surface of the double-row magnetic encoder track is cut by a plane including the axial direction of the magnetic encoder. The viewed cross section is provided obliquely with respect to the axial direction.

  According to this configuration, since the detection surface of the double-row magnetic encoder track is provided obliquely with respect to the axial direction, the axial direction is more compact than the magnetic encoder having the radial type structure, and the magnetic encoder having the axial type structure. It becomes more compact in the radial direction. When these double-row magnetic encoder tracks are provided on a cored bar, the bent part of the cored bar can be disposed along, for example, the outer peripheral surface and the end surface of the magnetic encoder. In this case, since the bent shape portion of the core metal separates the magnetic encoder tracks from each other, it is possible to prevent magnetic interference generated in the mutual magnetic patterns due to the close arrangement of the magnetic encoder tracks in the double row. It becomes possible. In addition, since it is not necessary to add a new component for preventing magnetic interference, the structure of the magnetic encoder can be simplified, the manufacturing cost can be reduced, and the magnetic encoder can be made more compact.

  The detection surfaces of adjacent double-row magnetic encoder tracks may be provided along one conical surface. In this case, for example, the detection surfaces of adjacent double-row magnetic encoder tracks are provided concentrically. According to this configuration, it is possible to improve the formability of the double-row magnetic encoder track. These detected surfaces can be easily post-processed along one conical surface, and the manufacturing cost can be reduced. It is also possible to simplify the structure of the mold for forming the double-row magnetic encoder track. Furthermore, repair of this mold can be facilitated. Therefore, the manufacturing cost can be further reduced.

  When the double-row magnetic encoder track is provided on a cored bar and the cored bar is made of a magnetic material, magnetic interference can be further effectively reduced. Even when a cored bar that is a non-magnetic material is adopted, the cored bar structure that supports the double-row magnetic encoder track provided obliquely with the detection surface of the double-row magnetic encoder track as described above, Magnetic interference between adjacent magnetic encoder tracks can be prevented. However, when a magnetic body is used, magnetic interference can be reduced more effectively and a more desirable configuration can be obtained. In this way, the cored bar can prevent magnetic interference generated in the magnetic patterns of the magnetic encoder tracks. Since the cored bar serves as a magnetic spacer, the number of parts can be reduced and the manufacturing cost can be reduced. Also, the assembly of the magnetic encoder can be simplified.

  The metal core may be L-shaped in a cross section viewed by cutting along a plane including the axial direction. In this case, even if the material of the metal core is a non-magnetic material, there is an effect that the distance between the magnetic encoder tracks is separated by the bent portion of the L-shaped metal core. For this reason, magnetic interference can be reduced. Therefore, it is possible to reduce the manufacturing cost associated with the change in the material of the cored bar and increase the degree of freedom in design.

  The cored bar may have one end in the L-shaped cross section interposed between adjacent magnetic encoder tracks. If one end of the core bar is covered with a double-row magnetic encoder track, the width of the magnetic spacer can be reduced, and the magnetic encoder can be made compact. When one end portion of the core bar is exposed from the magnetic encoder track, magnetic interference generated in the magnetic pattern of the magnetic encoder track can be further prevented.

  The double-row magnetic encoder track may be bonded to only one surface of the cored bar. In this case, the formability between the cored bar and the magnetic encoder track is improved, and peeling is unlikely to occur. Therefore, the durability of the magnetic encoder is increased.

The magnetic encoder track may be made of a material obtained by mixing magnetic powder with rubber or plastic.
The magnetic encoder track may include a rotation detection track in which magnetic poles are alternately repeated with an equal pitch magnetization pattern.

In the magnetic encoder track, one of the tracks formed in addition to the rotation detection track is provided with a repeating pattern once or several times per rotation, and generates a Z-phase signal indicating a reference position of rotation. There may be.
In the magnetic encoder track, one of the tracks formed in addition to the rotation detection track is formed with an equal pitch magnetization pattern having a magnetic pole interval different from the equal pitch magnetization pattern for rotation detection. There may be.
In the magnetic encoder track, one of the tracks formed in addition to the rotation detection track is formed with a pattern having the same number of magnetic poles and a phase relationship shifted from the equal pitch magnetization pattern for rotation detection. There may be.
The magnetic encoder may be incorporated in a bearing.

A first rotation detection device according to the present invention is the rotation detection device including the magnetic encoder according to any one of claims 1 to 12 and a magnetic sensor for detecting a magnetic field of the magnetic encoder. Has a plurality of sensor elements arranged at positions shifted from each other within the magnetic pole pitch, and can obtain two-phase signal outputs of sin and cos, and detects by multiplying the position in the magnetic pole It is.
When the magnetic sensor has such a configuration, the magnetic field distribution of the magnetic encoder can be detected more finely as a sinusoidal signal based on an analog voltage rather than as an on / off signal, and an accurate absolute angle can be detected.

A second rotation detection device according to the present invention is the rotation detection device including the magnetic encoder according to any one of claims 1 to 12 and a magnetic sensor for detecting a magnetic field of the magnetic encoder. However, it is constituted by a line sensor in which sensor elements are arranged along the arrangement direction of the magnetic poles of the magnetic encoder, and generates a two-phase signal output of sin and cos by calculation to detect the position in the magnetic poles.
When the magnetic sensor is configured as such a line sensor, the influence of the distortion and noise of the magnetic field pattern is reduced, and the phase of the magnetic encoder can be detected with higher accuracy.

  The magnetic encoder of the present invention is a magnetic encoder having adjacent double-row annular magnetic encoder tracks, wherein the detection surface of the double-row magnetic encoder track is cut by a plane including the axial direction of the magnetic encoder. Since the cross section seen is provided obliquely with respect to the axial direction, the double-row magnetic encoder track can be easily magnetized without causing magnetic interference and the magnetization accuracy can be improved, thereby reducing the manufacturing cost. Can be planned.

  A first rotation detection device according to the present invention is the rotation detection device including the magnetic encoder according to any one of claims 1 to 12 and a magnetic sensor for detecting a magnetic field of the magnetic encoder. Has a plurality of sensor elements arranged at positions shifted from each other within the magnetic pole pitch, and can obtain two-phase signal outputs of sin and cos, and detects by multiplying the position in the magnetic pole Therefore, it is possible to easily magnetize the double-row magnetic encoder track without causing magnetic interference, improve the magnetization accuracy, and reduce the manufacturing cost.

  A second rotation detection device according to the present invention is the rotation detection device including the magnetic encoder according to any one of claims 1 to 12 and a magnetic sensor for detecting a magnetic field of the magnetic encoder. However, it is composed of a line sensor in which sensor elements are arranged along the arrangement direction of the magnetic poles of the magnetic encoder, and generates a two-phase signal output of sin and cos by calculation to detect a position in the magnetic pole. The double-row magnetic encoder track can be easily magnetized without causing magnetic interference, and the magnetization accuracy can be improved to reduce the manufacturing cost.

(A) is principal part sectional drawing of the magnetic encoder which concerns on one Embodiment of this invention, (B) is principal part sectional drawing which shows the example which exposed the edge part of the metal core of the magnetic encoder. It is a figure which shows each pattern example of the magnetic pole magnetized to each magnetic encoder track. It is principal part sectional drawing of the magnetic encoder which concerns on other embodiment of this invention. It is principal part sectional drawing of the magnetic encoder which concerns on other embodiment of this invention. It is principal part sectional drawing of the magnetic encoder which concerns on other embodiment of this invention. It is principal part sectional drawing of the magnetic encoder which concerns on other embodiment of this invention. (A) is a conceptual diagram of a rotation detecting device including any one of the magnetic encoders of the present invention and a magnetic sensor for detecting the magnetic field of the magnetic encoder, and (B) is an explanatory diagram of a configuration example of the magnetic sensor. . It is explanatory drawing of the other structural example of a magnetic sensor. It is principal part sectional drawing which shows the example which incorporated the magnetic encoder which concerns on either embodiment of this invention in the bearing. (A) is sectional drawing of the conventional radial type magnetic encoder, (B) is sectional drawing of the conventional axial type magnetic encoder.

An embodiment of the present invention will be described with reference to FIGS.
The magnetic encoder according to the embodiment of the present invention is applied to, for example, a rotation detection device used for rotation control of various motors. However, it is not limited to the rotation control of various motors.

  As shown in FIG. 1 (A), the magnetic encoder 1 includes a metal core 2 and double-row (two rows in this example) annular magnetic encoder tracks 3 and 4. The core metal 2 is made of, for example, a cylindrical magnetic body, and a part of the core metal 2 is formed in an inward flange shape. The flange-shaped bottom portion 5 is folded back to provide an overlapping portion 6 that overlaps with each other in the axial direction, and the one end portion 2a of the cored bar 2 is substantially matched with the outer diameter position of the cylindrical outer peripheral surface. That is, the cored bar 2 is L-shaped in a section viewed by cutting along a plane including the axial direction L1 of the magnetic encoder 1, and the cylindrical inner peripheral surface 7 is the outer peripheral surface 8a of the mounting target 8 made of a rotating member. It is designed to be press-fitted into. As the rotating member, for example, a rotating shaft, a motor shaft, a bearing inner ring, a bearing outer ring, or the like can be applied.

Further, the axial position of the magnetic encoder 1 relative to the mounting target 8 is defined by bringing the flange-shaped bottom surface 5 a into contact with the end of the mounting target 8. Double-row magnetic encoder tracks 3 and 4 are provided on the metal core 2.
In particular, the detected surfaces 3a and 4a of the double-row magnetic encoder tracks 3 and 4 are provided obliquely with respect to the axial direction L1 with respect to a cross section viewed by cutting along a plane including the axial direction L1. In this case, the detected surfaces 3a and 4a of the adjacent double-row magnetic encoder tracks 3 and 4 are provided along one conical surface. The detected surfaces 3a and 4a are provided concentrically, and the inclination angle α of the detected surfaces 3a and 4a is set to 45 degrees with respect to the axis L1, for example. However, the inclination angle α is not limited to 45 degrees.

  The metal core 2 includes a role as a magnetic spacer made of an annular magnetic material interposed between the magnetic encoder tracks 3 and 4 in adjacent rows. The material of the metal core 2 may be either a magnetic material or a non-magnetic material, and the distance between the magnetic encoder tracks can be separated by the bent shape portion of the L-shaped metal core 2. Interference can be reduced. When this metal core is made of a magnetic material, magnetic interference can be more effectively reduced. The metal core 2 prevents magnetic interference between adjacent double-row magnetic encoder tracks 3 and 4 due to the role as the magnetic spacer. The double-row magnetic encoder tracks 3 and 4 are covered up to one end 2a of the core metal 2 so that the one end 2a of the core metal 2 is not exposed from the magnetic encoder tracks 3 and 4. Further, the double-row magnetic encoder tracks 3 and 4 are bonded to only one surface of the cored bar 2. For this reason, the moldability of the cored bar 2 and the magnetic encoder tracks 3 and 4 is improved, and the magnetic encoder tracks 3 and 4 hardly peel off from the cored bar 2.

  10A and 10B, the bonding surface between the magnetic encoder tracks 3 and 4 and the cored bar 2 has a portion 2b that is perpendicular to the main surface 2a of the cored bar 2. . For this reason, there is a possibility that peeling occurs between the metal core 2 and the magnetic encoder tracks 3 and 4 due to the internal stress of the magnetic encoder tracks 3 and 4 generated at the time of thermal contraction.

As shown in FIG. 1A, the magnetic encoder tracks 3 and 4 are magnetized on an annular magnetic body made of, for example, a ferrite magnet, a rare earth alloy, or a sintered magnet formed by adding magnetic powder. There may be. Ferrites are desirable because they can be easily magnetized and the rust prevention treatment can be omitted. The magnetic encoder tracks 3 and 4 in each row are individually magnetized, for example. Specifically, the annular magnetic body is magnetized by a magnetizing head (not shown) partly in the circumferential direction while rotating the annular magnetic body around the axis. That is, index magnetization is performed. As a result, the track forming regions are set as magnetic encoder tracks 3 and 4 having different magnetization patterns.
In addition, the magnetic encoder tracks 3 and 4 may be made of rubber or plastic containing magnetic powder, and may become a rubber magnet or a plastic magnet by magnetization, respectively.

2A to 2D show examples of patterns of magnetic poles magnetized on each magnetic encoder track of the annular magnetic body using the above-described index magnetization or the like. In the pattern example of FIG. 2A, one row of magnetic encoder tracks 3 is magnetized alternately with different magnetic poles at equal pitches to form a rotation detection track. In the other magnetic encoder track 4 in one row, a rotation reference position detection magnetic pole is magnetized at one place (or a plurality of places) around the track to generate a Z-phase signal indicating the reference position of rotation. This is a phase signal generation track.
In the pattern example of FIG. 2B, different magnetic poles are alternately magnetized at equal pitches on one row of magnetic encoder tracks 3 to form a rotation detection track. The other magnetic encoder track 4 is magnetized with different magnetic poles alternately at equal pitches and magnetized with different number of magnetic poles from the rotation detection track to form another rotation detection track. It is.

  In the pattern example of FIG. 2 (C), different magnetic poles are alternately magnetized at equal pitches on one row of magnetic encoder tracks 3 to form a rotation detection track. The other magnetic encoder track 4 in the other row is magnetized with different magnetic poles alternately and with the same number of magnetic poles as the rotation detection track and with the magnetic poles shifted in phase to form another rotation detection track. Is.

In the pattern example of FIG. 2 (D), in order to form a pattern similar to the example of FIG. 2 (C) in each magnetic pole pair A of the magnetic encoder track 3 (4) with an axial type annular magnetic body, The width of the N magnetic pole and the width of the S magnetic pole are magnetized so that they are different from each other in the track outer half, that is, in the radial direction.
Even when these complicated magnetic patterns are formed, mutual magnetic interference is reduced by the cored bar 2 including a role as a magnetic spacer. For this reason, rotation detection can be performed with high accuracy.

  According to the magnetic encoder 1 described above, since the detection surfaces 3a and 4a of the double-row magnetic encoder tracks 3 and 4 are provided obliquely with respect to the axial direction L1, the magnetic structure of the radial type shown in FIG. The axial direction is more compact than the encoder, and the radial direction is more compact than the magnetic encoder having the axial type structure shown in FIG. These double-row magnetic encoder tracks 3 and 4 can be provided on the core metal 2, and the bent portion of the core metal 2 can be disposed along the outer peripheral surface 8 a and the end surface of the attachment object 8. In this case, since the bent portion of the core metal 2 separates the magnetic encoder tracks 3 and 4 from each other, it serves as a magnetic spacer. For this reason, it becomes possible to prevent the magnetic interference which generate | occur | produces in the mutual magnetic pattern resulting from arranging the double-row magnetic encoder track | trucks 3 and 4 close. In addition, since it is not necessary to add a new component for preventing magnetic interference, the structure of the magnetic encoder 1 can be simplified, the manufacturing cost can be reduced, and the magnetic encoder 1 can be made more compact. The assembly of the magnetic encoder 1 can be simplified as compared with the case where a magnetic spacer is additionally provided in addition to the cored bar.

  Since the detection surfaces 3a and 4a of the adjacent double-row magnetic encoder tracks 3 and 4 are provided along one conical surface, the formability of the double-row magnetic encoder tracks 3 and 4 can be improved. These detected surfaces 3 and 4 can be easily post-processed along one conical surface, and the manufacturing cost can be reduced. It is also possible to simplify the structure of the mold for molding the double-row magnetic encoder tracks 3 and 4. Furthermore, repair of this mold can be facilitated. Therefore, the manufacturing cost can be further reduced.

  Since the core metal 2 has an L-shaped cross section, the magnetic encoder tracks 3 and 4 are separated from each other by the bent portion of the L-shaped core metal 2 even if the core metal 2 is made of a non-magnetic material. effective. For this reason, magnetic interference can be reduced. Therefore, it is possible to reduce the manufacturing cost associated with the material change of the cored bar 2 and to increase the degree of design freedom.

  The cored bar 2 has one end 2a in the L-shaped cross section interposed between adjacent magnetic encoder tracks 3 and 4. When one end 2a of the metal core 2 is covered with double-row magnetic encoder tracks 3 and 4, the axial direction X1 of the radial type magnetic encoder shown in FIG. 1 (A) is the axis of the conventional structure shown in FIG. 10 (A). The radial direction Y1 of the axial type magnetic encoder shown in FIG. 1B is more compact than the radial direction Y of the conventional structure of FIG. 10A, and the magnetic encoder 1 is made compact. Therefore, the magnetic encoder 1 satisfying a desired magnetic field strength can be obtained.

Since the double-row magnetic encoder tracks 3 and 4 are bonded and provided only on one surface of the cored bar 2, the formability between the cored bar 2 and the magnetic encoder tracks 3 and 4 is improved. As a result, even when the magnetic encoder tracks 3 and 4 are thermally contracted at the time of thermal contraction, separation between the core metal 2 and the magnetic encoder tracks 3 and 4 hardly occurs. 4 can be fixed stably. Therefore, the durability of the magnetic encoder 1 can be increased.
As shown in FIG. 1B, when one end 2a of the metal core 2 is exposed from the magnetic encoder tracks 3 and 4, magnetic interference generated in the magnetic patterns of the magnetic encoder tracks can be further prevented. Other effects similar to those of FIG.

  Another embodiment of the present invention will be described. In the following description, the same reference numerals are given to portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  As shown in FIG. 3, it is good also as the core metal 2 of a L-shaped cross section, without providing an overlap part in the bottom part 5 of the metal core 2. As shown in FIG. In this example, the corner portion 2 c of the bent shape portion of the core metal 2 is exposed from the double-row magnetic encoder tracks 3 and 4. According to this structure, the process which folds the bottom part 5 of the metal core 2 and overlaps each other in the axial direction can be reduced. Therefore, the manufacturing cost can be reduced. Also in this case, since the detection surfaces 3a and 4a of the double-row magnetic encoder tracks 3 and 4 are provided obliquely with respect to the axial direction L1, the axial direction and the radial direction can be made compact.

  As shown in FIG. 4, the overlapping portion of the cored bar 2 is omitted, and the cored bar 2 is press-fit into the L-shaped cross-sectional portion 9 to which the magnetic encoder tracks 3 and 4 are fixed, and the outer peripheral surface 8 a of the mounting target 8. A mating portion 10 may be provided. Further, the L-shaped cross-section portion 9 of the cored bar 2 is provided integrally with the fitting portion 10 via the connecting portion 11. Also in this case, it is possible to reduce the man-hours for processing the core metal 2 and reduce the manufacturing cost.

As shown in FIG. 5, the inclination angle α of the detected surfaces 3a and 4a of the double-row magnetic encoder tracks 3 and 4 may be opposite to that of FIG. In the core metal 2 of this example, the fitting portion 10 extends to the core metal body 12 forming the track. In this case, since the magnetic encoder tracks 3 and 4 may not be provided on the outer peripheral surface of the fitting portion 10 of the core metal 2, the tip of the fitting portion 10 of the core metal 2 can be easily elastically deformed. Therefore, the fitting portion 10 of the cored bar 2 can be easily press-fitted and fitted into the outer peripheral surface 8 a of the attachment target 8. Therefore, the assembly property of the magnetic encoder 1 is improved.
As shown in FIG. 6, the cored bar 2 may be integrally provided with the fitting part 10 via the stepped part 13 on the cored bar body 12 forming the track. In this case, the tip of the fitting portion 10 of the cored bar 2 can be more easily elastically deformed because the stepped portion 13 is interposed. Therefore, the assembly property of the magnetic encoder 1 is improved. In the examples of FIGS. 5 and 6, the tact time for assembling the magnetic encoder 1 can be reduced, and the manufacturing cost can be reduced.

As shown in FIG. 7A, a rotation detection device 19 including any one of the magnetic encoders 1 of the present invention and magnetic sensors 18A and 18B for detecting the magnetic field of the magnetic encoder 1 can be realized. The magnetic sensors 18A and 18B have a function of detecting magnetic poles with a resolution higher than the number of magnetic pole pairs of the corresponding magnetic encoder tracks 4 and 3, that is, a function of detecting position information within the magnetic pole ranges of the magnetic encoder tracks 4 and 3. It is supposed to have. In order to satisfy this function, for example, as the magnetic sensor 18A, when the pitch λ of one magnetic pole pair of the corresponding magnetic encoder track 4 is one cycle, the phase difference (λ / 4) is 90 degrees as shown in FIG. Using two magnetic sensor elements 18A1 and 18A2 such as Hall elements that are arranged apart from each other in the arrangement direction of the magnetic poles so that It may be calculated by multiplying the magnetic pole phase (φ = tan ⁻¹ (sinφ / cosφ)). The same applies to the other magnetic sensors 18B. The waveform diagram of FIG. 7B shows the arrangement of the magnetic poles of the magnetic encoder 4 in terms of magnetic field strength.
When the magnetic sensors 18A and 18B have such a configuration, the magnetic field distribution of the magnetic encoder tracks 4 and 3 can be detected more finely as a sinusoidal signal based on an analog voltage rather than as an on / off signal, and an accurate absolute angle detection can be performed. Is possible.

As another example of the magnetic sensors 18A and 18B having a function of detecting position information in the magnetic pole of the magnetic encoder, a line sensor as shown in FIG. 8B may be used. That is, for example, as the magnetic sensor 18A, line sensors 18AA and 18AB in which the magnetic sensor elements 18a are arranged along the arrangement direction of the magnetic poles of the corresponding magnetic encoder track 4 are used. FIG. 8A shows a section of one magnetic pole in the magnetic encoder track 4 converted into a magnetic field strength and shown in a waveform diagram. In this case, the first line sensor 18AA of the magnetic sensor 18A is arranged in association with the 90-degree phase section of the 180-degree phase section in FIG. 8A, and the second line sensor 18AB is the remaining 90. It is arranged in correspondence with the phase interval of degrees. With such an arrangement, the signal S1 obtained by adding the detection signal of the first line sensor 18AA by the adder circuit 20 and the signal S2 obtained by adding the detection signal of the second line sensor 18AB by the adder circuit 21 are added to another adder circuit. By adding at 22, a sin signal corresponding to the magnetic field signal as shown in FIG. 8C is obtained. Further, the signal S1 and the signal S2 via the inverter 23 are added by another adding circuit 24 to obtain a cos signal corresponding to the magnetic field signal as shown in FIG. The position in the magnetic pole is detected from the two-phase output signal thus obtained.
When the magnetic sensors 18A and 18B are configured by line sensors in this way, the effects of distortion of the magnetic field pattern and noise are reduced, and the phases of the magnetic encoder tracks 4 and 3 can be detected with higher accuracy.

  As shown in FIG. 9, any one of the magnetic encoders 1 of the embodiments and magnetic sensors 18 </ b> A and 18 </ b> B for detecting the magnetic field of the magnetic encoder 1 may be provided on the rolling bearing. For example, a deep groove ball bearing is applied to the rolling bearing, and includes an inner ring 14, an outer ring 15, a rolling element 16, and a seal member 17. In this example, the core metal 2 of the magnetic encoder 1 is press-fitted into the outer peripheral surface 14a on the right side of FIG. An inner peripheral surface 25a of a sensor metal core 25 that holds the magnetic sensors 18A and 18B is press-fitted to the inner peripheral surface. A resin member 26 made of a non-magnetic material is provided inside the sensor core 25, and magnetic sensors 18A and 18B are embedded in the resin member 26. Thus, when the magnetic encoder 1 etc. are provided in a rolling bearing, the precision of rotation detection can be improved.

DESCRIPTION OF SYMBOLS 1 ... Magnetic encoder 2 ... Core metal 3, 4 ... Magnetic encoder track 3a, 4a ... Detected surface

Claims (14)

In a magnetic encoder having adjacent double-row annular magnetic encoder tracks,
A magnetic encoder characterized in that a detected surface of the double-row magnetic encoder track is provided obliquely with respect to the axial direction with respect to a cross section obtained by cutting along a plane including the axial direction of the magnetic encoder.   2. The magnetic encoder according to claim 1, wherein the detection surfaces of adjacent double-row magnetic encoder tracks are provided along one conical surface.   3. The magnetic spacer according to claim 1 or 2, wherein the double-row magnetic encoder track is provided on a core bar, and the core bar is a magnetic spacer made of an annular magnetic body interposed between adjacent magnetic encoder tracks. Magnetic encoder including the role of.   The magnetic encoder according to claim 3, wherein the cored bar has an L shape in a cross section viewed by cutting along a plane including the axial direction.   5. The magnetic encoder according to claim 4, wherein the cored bar has one end portion in the L-shaped cross section interposed between adjacent magnetic encoder tracks.   6. The magnetic encoder according to claim 3, wherein the double-row magnetic encoder track is bonded to only one surface of the cored bar.   7. The magnetic encoder according to claim 1, wherein the magnetic encoder track is made of a material obtained by mixing magnetic powder with rubber or plastic.   8. The magnetic encoder according to claim 1, wherein the magnetic encoder track includes a rotation detection track in which magnetic poles are alternately repeated with an equal pitch magnetized pattern. 9.   9. The Z-phase signal according to claim 8, wherein one of the tracks formed in addition to the rotation detection track is provided with a repetitive pattern once or several times per rotation to indicate a reference position of rotation. Magnetic encoder that is intended to generate.   9. The magnetic encoder track according to claim 8, wherein one of the tracks formed in addition to the rotation detection track is an equal pitch magnetization pattern having a magnetic pole interval different from the equal pitch magnetization pattern for rotation detection. The magnetic encoder that is to be formed.   9. The magnetic encoder track according to claim 8, wherein one of the tracks formed in addition to the rotation detection track is a pattern having the same number of magnetic poles as the rotation detection equal pitch magnetization pattern and having a phase relationship shifted. The magnetic encoder that is to be formed.   12. A magnetic encoder according to claim 1, wherein the magnetic encoder is incorporated in a bearing. A rotation detection apparatus comprising: the magnetic encoder according to any one of claims 1 to 12; and a magnetic sensor that detects a magnetic field of the magnetic encoder.
The magnetic sensor has a plurality of sensor elements arranged at positions shifted from each other within the magnetic pole pitch, and can obtain a two-phase signal output of sin and cos. A rotation detection device to detect. A rotation detection apparatus comprising: the magnetic encoder according to any one of claims 1 to 12; and a magnetic sensor that detects a magnetic field of the magnetic encoder.
The magnetic sensor is composed of a line sensor in which sensor elements are arranged along the arrangement direction of the magnetic poles of the magnetic encoder, and detects a position in the magnetic poles by generating a two-phase signal output of sin and cos by calculation. A rotation detection device.

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