JP2011080777A - Magnetic encoder, method for manufacturing the same and rotation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder which can easily be magnetized without causing magnetic interference, as to magnetic encoder tracks in a plurality of rows, and which also enables improvement in magnetization accuracy and reduction in the manufacturing cost, and to provide a method for manufacturing the encoder and a rotation detector. <P>SOLUTION: A core metal 2 is assembled by putting and fixing an overlap 12 of a spacer member 6 on a track forming part 7 of a core metal body 5. The magnetic encoder tracks 3A and 4A partitioned from each other by a spacer 11 are provided in individual magnetic encoder track forming areas in the track forming part 7 of the assembled core metal 2. Thereafter, the magnetic encoder tracks 3A and 4A of rows are magnetized separately. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

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

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).
In addition, a method for manufacturing a magnetic encoder magnetized with multiple magnetic poles is disclosed (Patent Document 5).

JP-T-2001-518608 Special Table 2002-541485 JP-A-6-58766 JP 2008-233069 A Japanese Patent No. 4024472

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.
Further, since it is difficult to match the signals magnetized to the respective magnetic encoders, it is necessary to set a phase transfer 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.

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

  The magnetic encoder according to the present invention includes a core metal body having a track forming portion capable of forming two or more rows of annular magnetic encoder tracks side by side, and between the formation areas of the individual magnetic encoder tracks in the track forming portion of the core metal body. And a spacer that is interposed between the spacer portion and the spacer member that is provided at the base end of the spacer portion and overlaps the track forming portion and is fixed to the core metal body at the overlapping portion. The magnetic encoder track formed in the track forming portion of the core bar is provided with magnetic encoder tracks partitioned from each other by the spacer portion.

According to this configuration, the cored bar can be assembled by overlapping and fixing the overlapping part of the spacer member on the track forming part of the cored bar body. Magnetic encoder tracks that are partitioned from each other by the spacer portion are provided in each magnetic encoder track forming region in the track forming portion of the assembled cored bar. Thereafter, if the magnetic encoder tracks in each row are individually magnetized, they can be easily magnetized without causing magnetic interference. In this case, deformation due to assembly of the magnetic encoder as in the conventional case does not occur, and the magnetic encoder tracks in each row can be magnetized with high accuracy.
Further, since the signals magnetized in the respective magnetic encoder tracks can be easily matched, it is not necessary to take measures such as setting a correction value or increasing the interval between a plurality of sensor elements. Therefore, it is possible to reduce the manufacturing cost.

Each of the core metal body and the spacer member has a cylindrical shape having an axial center parallel to the axial direction, and the core metal body is attached to a track forming cylinder portion that forms a track forming portion and the track forming cylinder portion. An attachment tube portion attached to a target, and the spacer member includes a cylindrical portion that forms the overlapping portion, and the spacer portion that extends in a flange shape radially outward from an end portion of the cylindrical portion, The inner peripheral surface of the cylindrical portion of the spacer member may be press-fitted and fitted to the outer peripheral surface of the track forming cylinder portion of the core metal body.
In this case, the inner peripheral surface of the cylindrical portion of the spacer member is press-fitted to the outer peripheral surface of the track forming cylinder portion of the core metal main body, thereby assembling the core metal main body and the spacer member to realize a radial type magnetic encoder. be able to.

The core metal body has a plate shape facing the axial direction, the spacer member has a plate shape with a cylindrical spacer portion and an overlapping portion facing the axial direction, and the core metal body has a magnetic encoder track formed in front. The track forming portion is provided with a cylindrical stepped portion, and the cylindrical portion of the spacer member is fitted to the stepped portion, and the spacer is formed on the front side of the track forming portion of the core metal body. The overlapping part of the member may be overlapped.
In this case, an axial type magnetic encoder can be realized by assembling the core metal body and the spacer member by fitting the cylindrical portion of the spacer member to the step portion of the track forming portion of the core metal body.

  The spacer member may be formed in an L-shaped cross section with a spacer portion and an overlapping portion. In this case, for example, by using a spacer member having a thickness of 0.5 mm or less, the width of the spacer portion interposed between the individual magnetic encoder tracks can be suppressed. Magnetic interference acting on each track can be suppressed while suppressing a decrease in magnetic force at the position where the sensor is disposed, so that magnetization can be performed with high accuracy.

  The intermediate portion of the spacer member may be the spacer portion that is bent in a substantially U-shaped cross-section, and the overlapping portion may extend from both substantially U-shaped base ends of the spacer portion in a direction away from each other. . In this case, the width of the spacer portion can be suppressed to about 0.5 mm by using a spacer member having a thickness of about 0.2 mm to 0.3 mm.

  Positioning means for positioning the core metal body and the spacer member is provided on one of the core metal body and the spacer member, and the positioning means places the spacer member on the core in a state where the overlapping portion is overlapped with the track forming portion. It may be regulated and positioned relative to the gold body. In this case, the positioning means facilitates the positioning of the core metal body and the spacer member, and the assembly accuracy of the core metal can be increased as compared with the case where the positioning means is not provided.

  The spacer member may be provided with a through hole for connecting adjacent magnetic encoder tracks. In this case, for example, when forming rubber or plastic, a “mold” for forming the magnetic encoder track can be disposed on the surface to be detected of the magnetic encoder track. Even when the “mold” is arranged in this way, rubber or plastic containing magnetic powder can be formed by spreading the material of the magnetic encoder track through the through holes in the double-row magnetic encoder track forming region. Accordingly, there is no track covering the spacer portion, and magnetic interference can be suppressed. For this reason, magnetization can be performed with high accuracy. Further, by connecting the double-row magnetic encoder tracks through the through-holes, the connection between the tracks is strengthened. In this case, higher speed rotation is also possible.

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.
Even such a complex magnetized pattern can be magnetized with high accuracy.

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.

  A method for manufacturing a magnetic encoder according to the present invention is a method for manufacturing a magnetic encoder comprising a cored bar and a double-row magnetic encoder track formed on the cored bar, wherein two or more annular magnetic encoder tracks are arranged side by side. A metal core body having a track forming portion that can be formed, a spacer portion that rises between the formation regions of the individual magnetic encoder tracks in the track formation portion of the metal core body, and a base end of the spacer portion. An assembling process for assembling a cored bar having an overlapping part that overlaps the track forming part and a spacer member fixed to the cored bar main body at the overlapping part, and after the assembling process, each magnetic in the track forming part A track in which unmagnetized magnetic encoder tracks are arranged in the encoder track forming area and separated from each other by the spacer portion. And forming process, after the track formation process, and a magnetizing step of magnetizing individual magnetic encoder track of each column.

  According to this configuration, the metal core is assembled by overlapping and fixing the overlapping portion of the spacer member on the track forming portion of the metal core body. -> Form an unmagnetized double-row magnetic encoder track. → Magnetize the magnetic encoder track. In this case, since the magnetic encoder track is formed after assembling the cored bar, the deformation caused by the assembly of the conventional magnetic encoder does not occur, and the magnetic encoder track of each row can be magnetized with high accuracy. Further, since the signals magnetized in the respective magnetic encoder tracks can be easily matched, it is not necessary to take measures such as setting a correction value or increasing the interval between a plurality of sensor elements.

  The magnetic encoder according to the present invention includes a core metal body having a track forming portion capable of forming two or more rows of annular magnetic encoder tracks side by side, and between the formation areas of the individual magnetic encoder tracks in the track forming portion of the core metal body. And a spacer that is interposed between the spacer portion and the spacer member that is provided at the base end of the spacer portion and overlaps the track forming portion and is fixed to the core metal body at the overlapping portion. Since the magnetic encoder tracks partitioned from each other by the spacer portions are provided in the magnetic encoder track forming regions of the track forming portion of the core metal, the magnetic encoder tracks of the double row can be easily produced without causing magnetic interference. It can be magnetized and the accuracy of magnetization can be improved to reduce the manufacturing cost.

  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 a two-phase signal output of sin and cos for detecting by multiplying the position in the magnetic pole. In addition, the double-row magnetic encoder track can be easily magnetized without causing magnetic interference, and the magnetizing accuracy can be improved, thereby reducing 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. Is composed of a line sensor in which sensor elements are arranged along the magnetic pole arrangement direction of the magnetic encoder, and generates a two-phase signal output of sin and cos by calculation to detect the position in the magnetic pole. The magnetic encoder track can be easily magnetized without causing magnetic interference, and the magnetizing accuracy can be improved to reduce the manufacturing cost.

  A method for manufacturing a magnetic encoder according to the present invention is a method for manufacturing a magnetic encoder including a cored bar and a double-row magnetic encoder track formed on the cored bar, wherein two or more annular magnetic encoder tracks are arranged side by side. A metal core body having a track forming portion that can be formed, a spacer portion that rises between the formation regions of the individual magnetic encoder tracks in the track formation portion of the metal core body, and a base end of the spacer portion. An assembling process for assembling a cored bar having an overlapping part that overlaps the track forming part and a spacer member fixed to the cored bar main body at the overlapping part, and after the assembling process, each magnetic in the track forming part A track in which unmagnetized magnetic encoder tracks are arranged in the encoder track forming area and separated from each other by the spacer portion. Since it includes a forming process and a magnetizing process in which each row of magnetic encoder tracks is individually magnetized after this track forming step, the double-row magnetic encoder tracks can be easily magnetized without causing magnetic interference. In addition, the magnetization accuracy can be improved and the manufacturing cost can be reduced.

It is principal part sectional drawing of the magnetic encoder which concerns on one Embodiment of this invention. (A) is a cross-sectional view at the stage of assembling the spacer member on the core metal body, (B) is a cross-sectional view at the stage of assembling the core metal, and (C) is a stage of forming the unmagnetized two-row magnetic encoder track. It is sectional drawing. It is a figure which shows the example magnetized by the magnetizing head part by part of the circumferential direction of this annular magnetic body, rotating an annular magnetic body. It is a figure which shows each pattern example of the magnetic pole magnetized to each magnetic encoder track | truck of a cyclic | annular magnetic body. (A) is sectional drawing of the step which assembles the metal core of the magnetic encoder which concerns on other embodiment of this invention, (B) is sectional drawing of the step which assembled the concentric metal bar, (C) is unmagnetized 2 It is sectional drawing of the step which formed the magnetic encoder track | truck of the row | line | column. It is principal part sectional drawing of the magnetic encoder which concerns on other embodiment of this invention. (A) is sectional drawing of the spacer member in the magnetic encoder which concerns on further another embodiment of this invention, (B) is a top view of the spacer member. (A) is sectional drawing of the spacer member in the magnetic encoder which concerns on other embodiment, (B) is sectional drawing of the spacer member in the magnetic encoder which concerns on further another embodiment. (A) is sectional drawing of the axial type magnetic encoder which concerns on embodiment of this invention, (B) is sectional drawing of the axial type magnetic encoder which concerns on other embodiment of this invention. (A) is sectional drawing of the magnetic encoder which concerns on further another embodiment of this invention, (B) is sectional drawing of the magnetic encoder which concerns on further another 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.

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. The following description also includes a description of a method for manufacturing the magnetic encoder.

The structure of the magnetic encoder may be either an axial type or a radial type, but in this example, the radial type magnetic encoder 1 will be described. The axial type magnetic encoder will be described later.
As shown in FIG. 1, 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 includes a core metal body 5 and a spacer member 6. In the case of the radial type magnetic encoder 1, the core metal body 5 and the spacer member 6 each have a cylindrical shape having an axis L <b> 1 parallel to the axial direction. The metal core body 5 has a track forming portion 7 that can form two or more rows of annular magnetic encoder tracks 3 and 4 side by side. The core metal body 5 includes a track forming cylinder portion that forms the track forming portion 7 and an attachment cylinder portion 10 that continues to the track forming cylinder portion via an annular step portion 9. The core metal body 5 is made of, for example, a pipe material made of a thin bearing steel having a thickness of 0.5 mm or less, a steel pipe, or other steel. The pipe material is drawn using, for example, a press machine or the like, so that the track forming portion 7, the annular step portion 9, and the mounting cylinder portion 10 are formed.

  The spacer member 6 includes a spacer portion 11 and an overlapping portion 12 that overlaps the track forming portion 7. The spacer member 6 includes a cylindrical portion that forms the overlapping portion 12 and the spacer portion 11 that extends radially outward from the end portion of the cylindrical portion in a flange shape. For example, the spacer member 6 is formed by bending a pipe member made of a magnetic material having a thickness of 0.5 mm or less into a L-shaped cross section between the spacer portion 11 and the overlapping portion 12 using a press machine or the like.

  The spacer portion 11 rises and is interposed between the formation regions of the individual magnetic encoder tracks 3 and 4 in the track forming portion 7. Magnetic encoder tracks 3 and 4 to be described later are arranged in each magnetic encoder track forming region in the track forming portion 7 so as to be partitioned from each other by a spacer portion 11. The overlapping portion 12 is provided at the base end of the spacer portion 11 and overlaps the track forming portion 7. In other words, the inner peripheral surface of the overlapping portion 12 of the spacer member 6 is press-fitted to the outer peripheral surface of the track forming cylinder portion that is the track forming portion 7 of the core metal body 5. In addition, the radial type magnetic encoder 1 is attached to a bearing or the like by press-fitting the inner peripheral surface of the mounting cylinder portion 10 of the core metal body 5 to the outer diameter surface of the rotating member 14 or the like. As the rotating member 14, for example, a rotating shaft, a motor shaft, a bearing outer ring, a bearing inner ring, or the like can be applied.

  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. The ferrite system is desirable in that it can be easily magnetized by the magnetizing method described later and the rust preventive treatment can be omitted. 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, respectively, by magnetization.

  In the example of FIG. 1, the detected surfaces 3a and 4a of the magnetic encoder tracks 3 and 4 adjacent in the axial direction are formed so as to be the same radial position. In this case, the detected surfaces 3a and 4a may be formed by aligning with the mold, or after the detected surfaces 3a and 4a are formed by the mold, cutting is performed so that the detected surfaces 3a and 4a are aligned. Also good. At the time of this cutting process, the outer peripheral edge part of the spacer part 11 is simultaneously cut. By aligning the detected surfaces 3a and 4a in this way, the gap management between the magnetized yoke and the magnet surface in the magnetizing process is facilitated, so that the magnetizing strength is stabilized and as a result, the magnetizing accuracy can be improved. it can.

Next, a method for manufacturing the magnetic encoder 1 will be described.
The manufacturing method of the magnetic encoder 1 includes an assembling process of assembling the cored bar 2 composed of the cored bar body 5 and the spacer member 6, and after this assembling process, in each magnetic encoder track forming region in the track forming part 7, the spacer part 11. The track forming process of providing unmagnetized magnetic encoder tracks that are partitioned and aligned with each other, and the magnetizing process of individually magnetizing the magnetic encoder tracks of each column after the track forming process.

First, as shown in FIG. 2A, the cored bar body 5 and the spacer member 6 are separately formed in the cored bar 2 that is a component of the magnetic encoder 1. Next, as shown in FIG. 2 (B), the inner peripheral surface of the overlapping portion 12 of the spacer member 6 is fitted into the outer peripheral surface of the track forming cylinder portion 8 of the core metal body 5 in a press-fitted state. Assemble gold 2. At this time, the spacer portion 11 is positioned in the axial direction so as to rise between the formation regions of the individual magnetic encoder tracks 3 and 4 in the track forming portion 7 of the core metal body 5. Therefore, the relative position of the spacer member 6 in the axial direction with respect to the core metal body 5 is determined.
Next, as shown in FIG. 2 (C), in the magnetic encoder track forming regions in the track forming portion 7 of the cored bar 2, annular unmagnetized magnets that are partitioned from each other by the spacer portion 11 and arranged adjacent to each other in the axial direction. Magnetic encoder tracks 3A and 4A are formed. Thereafter, the magnetic encoder tracks 3A and 4A in each row are individually magnetized.

  In the magnetizing process, as shown in FIG. 3, the metal core body 5 is supported by a spindle device (not shown). The unmagnetized magnetic encoder tracks 3A and 4A are magnetized by the magnetizing head 15 partly in the circumferential direction of the magnetic encoder tracks 3A and 4A while rotating around the axis L1. 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. The magnetizing head 15 is obtained by winding an exciting coil 17 around a magnetizing yoke 16. The magnetized yoke 16 has a pair of opposed end portions 16a and 16b that are opposed to each other with a magnetic gap. By supplying an exciting current to the exciting coil 17 from a magnetized power source (not shown), both opposed end portions 16a and 16b are provided. Pass magnetic flux between them. A desired row of magnetic encoder tracks 3 (4) is arranged in the magnetic gap of the magnetized head 15.

By arranging the desired one row of magnetic encoder tracks 3 (4) so as to be sandwiched between the opposing ends 16a and 16b, the magnetic encoder tracks 3 (4) are magnetized through magnetic flux. In this case, the core metal body 5 is supported on the spindle device, and the spindle device is index-rotated. Each time this rotation is stopped, the energization direction to the exciting coil 17 is reversed. Thereby, the N magnetic pole and the S magnetic pole can be alternately magnetized in the circumferential direction of the magnetic encoder tracks 3 and 4.
By switching and controlling the energization direction to the exciting coil 17 in synchronization with the rotation of the spindle, it is possible to magnetize without stopping the rotation.

FIGS. 4A to 4D show examples of patterns of magnetic poles magnetized on each non-magnetized magnetic encoder track using the magnetization method shown in FIG. In the pattern example of FIG. 4A, different magnetic poles are alternately magnetized at equal pitches on one row of the magnetic encoder track 3 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. 4B, different magnetic poles are alternately magnetized at equal pitches on one row of the magnetic encoder track 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. 4C, rotation detection tracks are formed by alternately magnetizing different magnetic poles at equal pitches on one row of magnetic encoder tracks 3. 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. 4D, in order to form a pattern similar to the example of FIG. 4C in each magnetic pole pair A of the axial type magnetic encoder track 3 (4), The magnetic poles are magnetized so that the width of the S magnetic pole is different between the outer half of the track, that is, in the radial direction.

According to the magnetic encoder 1 described above, the cored bar 2 can be assembled by overlapping and fixing the overlapping part 12 of the spacer member 6 on the track forming part 7 of the cored bar body 5. Magnetic encoder tracks 3A and 4A that are partitioned from each other by a spacer portion 11 are provided in each magnetic encoder track forming region in the track forming portion 7 of the assembled cored bar 2. Thereafter, if the magnetic encoder tracks 3A and 4A in each row are individually magnetized, they can be easily magnetized without causing magnetic interference. In this case, deformation due to the assembly of the magnetic encoder as in the prior art does not occur, and the magnetic encoder tracks 3A and 4A in each row can be magnetized with high accuracy.
In addition, since the signals magnetized in the magnetic encoder tracks 3 and 4 can be easily matched, it is necessary to take measures such as setting a correction value or increasing the interval between a plurality of sensor elements. Disappear. Therefore, it is possible to reduce the manufacturing cost.

  Since the spacer member 6 is formed in an L-shaped cross section with the spacer portion 11 and the overlapping portion 12, for example, by using the spacer member 6 having a thickness of 0.5 mm or less, each magnetic encoder track 3, The width of the spacer portion 11 interposed between the four can be suppressed. Magnetic interference acting on each track can be suppressed while suppressing a decrease in magnetic force at the position where the sensor is disposed, so that magnetization can be performed with high accuracy.

  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. 5, a spacer portion 11A is formed by bending an intermediate portion of the spacer member 6A into a folded state having a substantially U-shaped cross section, and the spacer portions 11A are separated from both substantially U-shaped base ends. It is good also as the overlapping part 12 extended in this. In this case, the width of the spacer portion 11A can be suppressed to about 0.5 mm by using the spacer member 6A having a thickness of about 0.2 mm to 0.3 mm. This spacer member 6A can also be easily formed by bending a pipe member made of a magnetic material into a substantially U-shaped cross section using a press machine or the like. Since it is not necessary to provide a separate part as the spacer portion 11A, the number of parts can be reduced and the manufacturing cost can be reduced. As shown in FIG. 5C, since there are overlapping portions 12 and 12 on each side of the two rows of magnetic encoder tracks 3 and 4, when the detected surfaces 3a and 4a are aligned, two rows of magnetic encoder tracks 3 are arranged. , 4 can be made equal. For this reason, the magnetic field strength of the two rows of magnetic encoder tracks 3 and 4 can be made uniform.

As shown in FIG. 6, the cored bar body 5 may be provided with an annular stepped portion serving as positioning means 18 for positioning the cored bar body 5 and the spacer member 6 in the axial direction. The annular stepped portion is a stepped portion on the outer diameter side that extends radially outward from the track forming cylinder portion 8. The metal core body 5 has a maximum diameter cylindrical portion 20 extending in the axial direction from the outer peripheral edge portion of the positioning means 18. The maximum diameter cylindrical portion 20, the positioning means 18, the track forming cylindrical portion 8, the annular stepped portion 9, and the mounting cylindrical portion 10 are formed by drawing the above-described pipe material using, for example, a press machine. The inner peripheral surface of the overlapping portion 12 of the spacer member 6 is press-fitted to the outer peripheral surface of the track forming cylinder portion 8, and the base end side end surface of the spacer portion 11 is brought into contact with the positioning means 18. Thereby, the spacer member 6 is relatively regulated and positioned with respect to the core metal body 5.
According to this configuration, the positioning means 18 makes it easy to position the core metal body 5 and the spacer member 6, and the assembly accuracy of the core metal 2 can be increased as compared with those in which no positioning means is provided. The magnetic encoder track 3 arranged on the maximum diameter cylinder portion 20 side is made thinner than the magnetic encoder track 4 arranged on the track forming cylinder portion 8 side, and the magnetic field strength of the two rows of magnetic encoder tracks 3 and 4 is increased. A difference can also be provided.

  As shown in FIG. 7, the spacer member 6 may be provided with a through hole h that connects the adjacent magnetic encoder tracks 3 and 4. FIG. 7A is a cross-sectional view of the spacer member 6, and FIG. 7B is an end view taken along the line BB of FIG. 7A. The through holes h are formed at equal intervals in a plurality of locations (four locations in this example) in the circumferential direction of the spacer member 6. Each through-hole h is formed from the radial base end portion of the spacer portion 11 to the axial base end portion of the overlapping portion 12 and is formed in a semicircular shape when viewed from the front.

  In this case, when the double-row magnetic encoder tracks 3 and 4 are formed of rubber or plastic material containing magnetic powder, for example, when rubber or plastic is formed, the detected surfaces 3a and 4a of the magnetic encoder tracks 3 and 4 are formed. A “mold” for forming a magnetic encoder track can be placed on the surface. Even if the “mold” is arranged in this way, rubber or plastic containing magnetic powder can be formed by flowing rubber and plastic material through the through holes h and spreading them in the double row magnetic encoder track forming region. Further, by connecting the double-row magnetic encoder tracks 3 and 4 through the through holes h, the connection between the tracks is strengthened. By forming the magnetic encoder tracks 3 and 4 in this way, there is no track that covers the spacer portion 11, and magnetic interference can be suppressed. For this reason, magnetization can be performed with high accuracy. Further, it is possible to reduce the weight of the magnetic encoder as compared with the case where no through hole is provided.

  As another example of the through hole, as shown in FIG. 8 (A), a through hole h having a perfect circular shape in front view may be used. As shown in FIG. 8 (B), a through hole h having a long hole shape in front view may be used. It is also good. Further, it is sufficient that at least one through hole h is provided in the spacer member 6.

As shown in FIG. 9A, in the case of the axial type magnetic encoder 1, the core metal body 5 has a plate shape made of a steel plate or the like facing the axial direction. The spacer member 6 has a plate shape in which the spacer portion 11 is cylindrical and the overlapping portion 12 faces the axial direction. The cored bar body 5 is formed by, for example, pressing, etc., and is connected to the track forming portion 7 and the inner diameter side of the track forming portion 7 via the stepped portion 21 to the inner diameter side of the track forming portion 7. Part 22.
The cored bar body 5 has a cylindrical portion 23 that extends in a cylindrical shape from the inner peripheral side end portion of the inner diameter side plate portion 22. The inner peripheral surface of the cylindrical portion 23 can be attached by press-fitting and fitting to the outer peripheral surface of the rotating member 14, for example. In the case where the inner diameter side plate portion 22 is fixed to the end face of the rotating member 14, the cylindrical portion 23 may be omitted. The track forming portion 7 is provided with a cylindrical step portion 7a, and the spacer portion 11 is fitted and fixed to the step portion 7a in the radial direction. Further, the overlapping portion 12 of the spacer member 6 is overlapped on the front side of the track forming portion 7 of the core metal body 5. Therefore, two rows of magnetic encoder tracks 3 and 4 partitioned from each other by the spacer portion 11 are arranged side by side in the radial direction.
In the axial type magnetic encoder 1 shown in FIG. 9B, the stepped portion 21 and the inner diameter side plate portion 22 having the configuration shown in FIG. 9A are omitted, and the cylindrical portion 23 extends from the inner peripheral side end of the track forming portion 7. Continue in a cylindrical shape. 9A and 9B, the plate-like overlapping portion 12 facing the axial direction in the spacer member 6 may be omitted. In these cases, the fitting portion in the radial direction of the spacer portion 11 with respect to the stepped portion 7 a corresponds to an overlapping portion fixed to the core metal body 5.
As shown in FIG. 10A, the track forming cylinder portion 8 may have a smaller diameter than the mounting cylinder portion 10 and the annular stepped portion 9 may be in contact with the end surface of the rotating member 14 to be attached. Further, as shown in FIG. 10B, an annular stepped portion between the track forming cylinder portion 8 and the mounting cylinder portion 10 is omitted, and an annular notch portion 14a provided on the outer diameter surface of the rotating member 14 is provided. The inner peripheral surface of the mounting cylinder portion 10 may be press-fitted and fitted.

As shown in FIG. 11A, a rotation detection device 25 including any one of the magnetic encoders 1 of the present invention and magnetic sensors 24A and 24B for detecting the magnetic field of the magnetic encoder 1 can be realized. The magnetic sensors 24A, 24B 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, 3, that is, a function of detecting position information within the magnetic pole ranges of the magnetic encoder tracks 4, 3. It is supposed to have. In order to satisfy this function, for example, as the magnetic sensor 24A, 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 24A1 and 24A2 such as Hall elements arranged so as to be separated from each other in the arrangement direction of the magnetic poles, the two-phase signals (sinφ, cosφ) obtained by these two magnetic sensor elements 24A1 and 24A2 are used. It may be calculated by multiplying the magnetic pole phase (φ = tan ⁻¹ (sinφ / cosφ)). The same applies to the other magnetic sensors 24B. The waveform diagram of FIG. 11B shows the magnetic pole array of the magnetic encoder 4 converted to magnetic field strength.
When the magnetic sensors 24A and 24B 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 24A and 24B having a function of detecting position information in the magnetic pole of the magnetic encoder, a line sensor as shown in FIG. 12B may be used. That is, for example, as the magnetic sensor 24A, line sensors 24AA and 24AB in which the magnetic sensor elements 24a are arranged along the arrangement direction of the magnetic poles of the corresponding magnetic encoder track 4 are used. FIG. 12A 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 24AA of the magnetic sensor 24A is disposed in association with the 90-degree phase section of the 180-degree phase section in FIG. 12A, and the second line sensor 24AB 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 24AA by the adder circuit 26 and the signal S2 obtained by adding the detection signal of the second line sensor 24AB by the adder circuit 27 are different addition circuits. By adding at 28, a sin signal corresponding to the magnetic field signal as shown in FIG. Further, the signal S1 and the signal S2 via the inverter 29 are added by another adding circuit 30 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 24A and 24B are configured by line sensors in this way, the effects of distortion and noise of the magnetic field pattern are reduced, and the phases of the magnetic encoder tracks 4 and 3 can be detected with higher accuracy.

Three or more rows of magnetic encoder tracks may be formed side by side on the track forming portion 7 of the core metal body 5. As an alternative to the positioning means 18 shown in FIG. 6, a protruding portion that protrudes radially outward may be fixed to a part of the core metal body 5. The protrusions may be annular protrusions that are continuous in the circumferential direction, or one or a plurality of protrusions may be provided in the circumferential direction.
Further, the overlapping portion 12 of the spacer member 6 may be extended to the left in the axial direction from that of FIG. 1, and positioning means extending in a flange shape radially inward from the extended end portion may be provided. By positioning this positioning means against the annular step portion 9 of the core metal body 5, the core metal body 5 and the spacer member 6 may be positioned in the axial direction. In this case, the structure of the core metal body can be simplified as compared with that in FIG. In addition, the metal core body 5 and the spacer member 6 may be provided with positioning means including an engaging portion and an engaged portion.

DESCRIPTION OF SYMBOLS 1 ... Magnetic encoder 2 ... Core metal 3, 4 ... Magnetic encoder track 5 ... Core metal main body 6 ... Spacer member 7 ... Track formation part 7a ... Step part 8 ... Track formation cylinder part 9 ... Annular step part 10 ... Mounting cylinder part 11 ... Spacer part 12 ... Overlapping part 18 ... Positioning means 21 ... Step part 22 ... Inside diameter side plate parts 24A, 24B ... Magnetic sensor 25 ... Rotation detection device

Claims (15)

  A cored bar body having a track forming part capable of forming two or more rows of annular magnetic encoder tracks side by side, and a spacer part rising between the forming areas of the individual magnetic encoder tracks in the track forming part of the cored bar body And a cored bar provided with a spacer member provided at a base end of the spacer part and overlapping the track forming part, and a spacer member fixed to the cored bar body at the overlapping part, and the track of the cored bar is provided. A magnetic encoder characterized in that a magnetic encoder track partitioned by the spacer portion is provided in each magnetic encoder track forming region in a forming portion.   2. The core metal body and the spacer member according to claim 1, each of which has a cylindrical shape having an axial center parallel to the axial direction, and the core metal body includes a track forming cylinder portion forming a track forming portion, and the track forming portion. The spacer member includes a cylindrical portion that forms the overlapping portion, and the spacer portion that extends in a flange shape radially outward from an end portion of the cylindrical portion. A magnetic encoder in which the inner peripheral surface of the cylindrical portion of the spacer member is press-fitted and fitted to the outer peripheral surface of the track forming cylindrical portion of the core metal body.   2. The core metal body according to claim 1, wherein the core metal body is plate-shaped facing the axial direction, and the spacer member is a plate-shaped spacer part having a cylindrical shape and an overlapping part facing the axial direction. The track has a track forming portion formed on the front surface, a cylindrical step portion is provided in the track forming portion, and the cylindrical portion of the spacer member is fitted to the step portion, and the track forming portion of the core metal body is A magnetic encoder having a spacer member overlapped on the front side.   4. The magnetic encoder according to claim 1, wherein the spacer member is formed in an L-shaped cross section by a spacer portion and an overlapping portion.   4. The spacer portion according to claim 1, wherein the spacer member is formed by bending the intermediate portion of the spacer member into a folded state having a substantially U-shaped cross section. A magnetic encoder having the overlapping portion extending in a direction away from each other.   6. The positioning device according to claim 1, wherein positioning means for positioning the core metal body and the spacer member is provided on one of the core metal body and the spacer member. A magnetic encoder that positions and regulates the spacer member relative to the cored bar body in a state where the overlapping part is overlapped with the part.   The magnetic encoder according to any one of claims 1 to 6, wherein the spacer member is provided with a through-hole that connects adjacent magnetic encoder tracks.   8. 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.   9. 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 magnetization pattern. 10.   10. The Z-phase signal according to claim 9, wherein the magnetic encoder track is a Z-phase signal that indicates a reference position for rotation, wherein one of the tracks formed in addition to the rotation detection track is provided with a repeating pattern once or several times per rotation. Magnetic encoder that is intended to generate.   10. The magnetic encoder track according to claim 9, wherein one of the tracks formed in addition to the rotation detection track is an equal pitch magnetization pattern having a magnetic pole spacing different from the rotation detection equal pitch magnetization pattern. The magnetic encoder that is to be formed.   10. The magnetic encoder track according to claim 9, wherein one of the tracks formed in addition to the rotation detection track is a pattern having the same number of magnetic poles and a phase relationship shifted as the rotation detection equal pitch magnetization pattern. The magnetic encoder that is to be formed. 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. A method of manufacturing a magnetic encoder comprising a mandrel and a double-row magnetic encoder track formed on the mandrel,
A cored bar body having a track forming part capable of forming two or more rows of annular magnetic encoder tracks side by side, and a spacer part that rises and intervenes between the formation areas of the individual magnetic encoder tracks in the track forming part of the cored bar body And an assembling process for assembling a metal core formed of a spacer member provided at a base end of the spacer part and overlapping the track forming part and having a spacer member fixed to the metal core body at the overlapping part;
After this assembling process, a track forming process in which unmagnetized magnetic encoder tracks are arranged in the respective magnetic encoder track forming regions in the track forming part and are partitioned and aligned by the spacer part;
After this track formation process, a magnetization process for individually magnetizing each row of magnetic encoder tracks,
A method for manufacturing a magnetic encoder including:

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