JP2010032553A - Rotation sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation sensor capable of improving accuracy in rotation detection by preventing an output variation from differing when a magnetic rotating object to be detected approaches. <P>SOLUTION: A giant magnetoresistive element 17 in a first element area 16 and a giant magnetoresistive element 17 in a third element area 19 are inclined to exhibit a predetermined tilt angle in a direction of a magnetic path of a line of magnetic force generated from a magnet 11 approximately vertical to a direction of rotation of the magnetic rotating object 12 to be detected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention particularly relates to a rotation sensor that detects the number of rotations by a change in magnetism.

  This type of conventional rotation sensor has a configuration as shown in FIGS.

  FIG. 6 is a side view of a conventional rotation sensor, and FIG. 7 is a top view of elements in the rotation sensor.

  6 and 7, reference numeral 1 denotes a magnetic detection rotor, and a convex portion 2 is provided on the outer periphery of the magnetic detection rotor 1. Reference numeral 3 denotes a magnet, and the magnet 3 is provided so as to face the outer peripheral portion of the magnetic detected rotor 1. Reference numeral 4 denotes an element portion. As shown in FIG. 7, the element portion 4 is provided with a power supply electrode 5 on the upper surface. The power supply electrode 5 includes a first magnetoresistive element 6a and a second magnetoresistive element 6b. Are electrically connected at one end. Further, a third magnetoresistive element 6c is provided on the upper surface of the element portion 4, and one end of the third magnetoresistive element 6c is connected to the other end of the second magnetoresistive element 6b and the midpoint electrode 7. And the other end is electrically connected to the GND electrode 8. In addition, a fourth magnetoresistive element 6d is provided on the upper surface of the element portion 4, and one end of the fourth magnetoresistive element 6d is electrically connected to the other end of the first magnetoresistive element 6a. The other end is electrically connected to the GND electrode 8. The second magnetoresistive element 6b and the fourth magnetoresistive element 6d are located on the right side of the element portion 4 and provided close to each other, and the first magnetoresistive element 6a and the third magnetoresistive element The element 6c is located on the left side of the element part 4 and is provided close to each other. The first magnetoresistive element 6a, the second magnetoresistive element 6b, the third magnetoresistive element 6c, and the fourth magnetoresistive element 6d have a magnetosensitive surface in a direction perpendicular to the direction in which the magnetic force passes. Is provided.

  The element section 4 is inclined with a predetermined inclination angle with respect to the direction of the magnetic path of the magnetic lines of force generated from the magnet 3 in a direction substantially parallel to the rotating direction of the magnetic detection rotor 1. The first magnetoresistive element 6a and the third magnetoresistive element 6c are more effective against the magnet 3 than the second magnetoresistive element 6b and the fourth magnetoresistive element 6d in accordance with the inclination. It is provided at a close position.

  Next, the operation of the conventional rotation sensor configured as described above will be described.

  As shown in FIG. 6, when the magnetic detection rotor 1 rotates, the convex portion 2 provided on the outer peripheral portion of the magnetic detection rotor 1 is formed on the element portion 4 as the magnetic detection rotor 1 rotates. Approach or distant. The characteristics of the first magnetoresistive element 6a, the second magnetoresistive element 6b, the third magnetoresistive element 6c, and the fourth magnetoresistive element 6d are shown in FIG. Since the value decreases, the first magnetoresistive element 6a, the second magnetoresistive element 6b, the third magnetoresistive element 6c, and the fourth magnetoresistive element come when the convex portion 2 of the rotating body 1 to be detected approaches. The resistance value of 6d is configured to decrease. The first magnetoresistive element 6a, the second magnetoresistive element 6b, the third magnetoresistive element 6c, and the fourth magnetoresistive element 6d constitute a bridge circuit as shown in FIG. When the resistance values of the second magnetoresistive element 6b and the fourth magnetoresistive element 6d provided on the right side in FIG. 4 increase, the bridge circuit amplifies the output signal by the operational amplifier 9, and the magnetic detected rotor 1 The number of rotations was detected.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

Japanese Patent Laid-Open No. 10-239098

  However, in the above-described conventional configuration, the second magnetoresistive element 6b and the fourth magnetoresistive element 6d in the element unit 4 are located far from the magnet 3, and the first magnetoresistive element 6a and the third magnetoresistive element 6a Since the magnetoresistive elements 6c are close to each other, the location of the operation of each magnetoresistive element in the magnetic resistance curve shown in FIG. 9 is different, whereby the second magnetoresistive element 6b and the fourth magnetoresistive element 6c. The magnetoresistive element 6d, the first magnetoresistive element 6a, and the third magnetoresistive element 6c differ in the amount of change in output when the convex portion 2 of the magnetic body to be detected rotating body 1 approaches. It had the problem of getting worse.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a rotation sensor capable of improving the accuracy of rotation detection by eliminating the difference in output change when a magnetic detection target rotating body approaches. It is what.

  In order to achieve the above object, the present invention has the following configuration.

  The invention described in claim 1 of the present invention is provided in a magnet disposed opposite to the magnetic body to be detected, a holder for housing the magnet and having a yoke insertion hole, and a yoke insertion hole of the holder. And a yoke for adjusting the magnetic path of the lines of magnetic force generated from the magnet, and a magnetically sensitive surface between the magnet and the magnetic detection rotating body is predetermined from a direction substantially perpendicular to the direction in which the magnetic detection rotating body and the magnet face each other. Three element portions having four magnetoresistive elements provided so as to be inclined so as to form an inclination angle, an element mounting member for tilting and mounting these three element portions, and an output signal from the magnetoresistive element A circuit board provided with a circuit unit for processing the substrate, and a plurality of connectors that house the magnet, holder, yoke, magnetoresistive element, element mounting member, and circuit board and are electrically connected to the circuit part of the circuit board. The three element portions with a predetermined inclination angle with respect to the direction of the magnetic path of the magnetic force lines generated from the magnet in a direction substantially perpendicular to the direction in which the magnetic detection target rotating body rotates. According to this configuration, the magnetoresistive element is inclined with respect to the direction of the magnetic path of the magnetic force lines generated from the magnet in a direction substantially perpendicular to the direction of rotation of the magnetic detection target rotating body. Therefore, the magnetosensitive surface of the magnetoresistive element in the element portion is inclined with respect to the magnetic field lines generated from the magnet. Since the distance to the detection rotator is the same, the location where each magnetoresistive element operates on the magnetic resistance curve is the same, so that the amount of output change when the outer periphery of the magnetic detection rotator approaches For each magnetoresistive element To become equal to have, and has effects of improving the rotation detection accuracy.

  Further, the invention according to claim 2 is provided with an insertion hole into which the element mounting member is fitted in the case, and the magnetoresistive element is made to face the magnetic detection rotor through the insertion hole. According to the configuration, the insertion hole into which the element mounting member is fitted is provided in the case, and the magnetoresistive elements in the first element portion, the second element portion, and the third element portion are magnetically detected through the insertion hole. By facing the rotating body, the magnetoresistive elements in the first element portion, the second element portion, and the third element portion are close to the magnetic detection rotating body. As a result, the sensitivity of the output signal of the rotation sensor can be improved.

  As described above, the rotation sensor of the present invention is provided with a magnet disposed opposite to the magnetic body to be detected, a holder that houses the magnet and is provided with a yoke insertion hole, a yoke insertion hole of the holder, and A yoke that adjusts the magnetic path of the lines of magnetic force generated from the magnet, and a magnetosensitive surface between the magnet and the magnetically detected rotating body has a predetermined inclination from a direction substantially perpendicular to the facing direction of the magnetically detected rotating body and the magnet. Three element portions having four magnetoresistive elements provided so as to be inclined so as to form an angle, an element mounting member for mounting these three element portions while being inclined, and an output signal from the magnetoresistive element A circuit board provided with a circuit section to be processed, and a plurality of cores that house the magnet, holder, yoke, magnetoresistive element, element mounting member, and circuit board and are electrically connected to the circuit section of the circuit board. The three element portions are arranged at a predetermined inclination angle with respect to the direction of the magnetic path of the magnetic lines of force generated from the magnet in a direction substantially perpendicular to the direction in which the magnetic detection target rotating body rotates. According to this configuration, the magnetoresistive element is inclined with respect to the direction of the magnetic path of the magnetic force lines generated from the magnet in a direction substantially perpendicular to the direction of rotation of the magnetic detection target rotating body. Therefore, the magnetosensitive surface of the magnetoresistive element in the element portion is inclined with respect to the magnetic field lines generated from the magnet. Since the distance to the detection rotator is the same, the location where each magnetoresistive element operates on the magnetic resistance curve is the same, so that the amount of output change when the outer periphery of the magnetic detection rotator approaches Each magnetoresistive element Since the Oite equivalent, in which an excellent effect that it is possible to provide a rotation sensor having an improved rotation detection accuracy.

The exploded perspective view of the rotation sensor in one embodiment of the present invention Side sectional view of element mounting member in the same rotation sensor The perspective view of the element mounting member in the rotation sensor Top view of first element portion in rotation sensor Side sectional view which shows the state through which the magnetic force line which generate | occur | produces from the magnet passes the element mounting member in a rotation sensor Side view of a conventional rotation sensor Top view of the element part of the rotation sensor Circuit diagram of the rotation sensor The characteristic diagram which shows the characteristic of the magnetoresistive element in the same rotation sensor

  Hereinafter, the invention described in claims 1 to 2 of the present invention will be described using an embodiment.

  1 is an exploded perspective view of a rotation sensor according to an embodiment of the present invention, FIG. 2 is a side sectional view of an element mounting member in the rotation sensor, FIG. 3 is a perspective view of an element mounting member in the rotation sensor, and FIG. FIG. 5 is a side sectional view showing a state in which magnetic lines of force generated from a magnet pass through an element mounting member in the same rotation sensor.

  In FIG. 1 to FIG. 5, reference numeral 11 denotes a magnet. The magnet 11 is provided so as to be opposed to the magnetic detection rotating body 12 made of a counter gear, and the outer periphery of the magnetic detection rotating body 12. The portion is provided with a plurality of convex portions 12a over the entire circumference. Reference numeral 13 denotes a resin holder. The holder 13 accommodates the magnet 11 inside, and has a pair of yoke insertion holes 14 on the upper surface. Reference numeral 15 denotes a pair of yokes provided in the pair of yoke insertion holes 14 in the holder 13, and the magnetic path of magnetic lines of force generated from the magnet 11 is adjusted by the yoke 15.

  Reference numeral 16 denotes a first element portion. As shown in FIG. 4, the first element portion 16 includes a flexible wiring board 16a and four giant magnetoresistive elements 17 provided on the upper surface of the flexible wiring board 16a. The giant magnetoresistive element 17 detects the magnetic force generated from the magnet 11. Reference numeral 18 denotes a second element portion. The second element portion 18 is provided in parallel with the first element portion 16 and, like the first element portion 16, 4 on the upper surface of the flexible wiring board 16 a. Two giant magnetoresistive elements 17 are provided. Reference numeral 19 denotes a third element portion. The third element portion 19 is provided in parallel with the first element portion 16 and the second element portion 18, and four giant magnetoresistive elements 17 are provided on the upper surface. Yes. As shown in FIG. 2, the four giant magnetoresistive elements 17 in the first element section 16 are arranged between a magnet (not shown) and a magnetically detected rotating body (not shown). Is provided so as to be inclined at a predetermined inclination angle from substantially perpendicular to the direction in which the magnetic detection rotor and the magnet face each other, and substantially perpendicular to the direction of rotation of the magnetic detection rotor. It is configured to tilt about 25 degrees in the lower right direction with respect to the direction of the magnetic path of the magnetic lines of force generated from the magnet in any direction.

  As described above, the four giant magnetoresistive elements 17 in the first element unit 16 are generated from magnets (not shown) in a direction substantially perpendicular to the direction of rotation of the magnetic detection target rotating body (not shown). Since it is configured to be tilted by about 25 degrees in the lower right direction with respect to the direction of the magnetic path of the magnetic field lines, the giant magnetism in the first element portion 16 with respect to the magnetic field lines generated from the magnet 11 as shown in FIG. Since the magnetosensitive surface of the resistance element 17 is inclined, and the distance between the four giant magnetoresistive elements 17 and the magnet 11 becomes the same, the magnetic resistance of the giant magnetoresistive element 17 in the first element portion 16 is the same. The portions that operate in a curve are equivalent, and accordingly, the amount of change in output when the convex portion 12a of the magnetic body to be detected rotating body 12 shown in FIG. Improve detection accuracy In which there is an advantage that it is possible to.

  Further, as shown in FIG. 2, the third element unit 19 is configured to be inclined by about 25 degrees in the lower left direction opposite to the first element unit 16, and the first element unit 16 The second element part 18 located approximately in the center between the first element part 19 and the third element part 19 is inclined to the lower right by about 20 degrees, and the inclination angle of the second element part 18 is the first element. The inclination angle of the part 16 and the third element part 19 is made smaller.

  Reference numeral 20 denotes an element mounting member made of resin. As shown in FIG. 5, the element mounting member 20 includes the first element portion 16, the second element portion 18 and the four giant magnetoresistive elements 17 described above. The third element portion 19 is fixed on the inner side, and a yoke 15 is provided on the magnet 11 side so as to face the first element portion 16 and the third element portion 19 located on the outer side. With such a configuration, the magnetic force generated from the magnet 11 can be generated vertically from the yoke 15, so that the magnetic force is generated outward of the first element portion 16 and the third element portion 19 located outside. Is not leaked, and this can improve the sensitivity of the output signals output from the first element portion 16 and the third element portion 19.

  Reference numeral 21 denotes a circuit board. The circuit board 21 is provided with a circuit portion 22 on the upper surface, and the circuit portion 22 converts a sinusoidal output signal generated from the giant magnetoresistive element 17 into a rectangular wave. Reference numeral 23 denotes a case made of resin. The case 23 houses the magnet 11, the holder 13, the yoke 15, the element mounting member 20, and the circuit board 21, and is provided with ten connector terminals 24 toward the outside. The connector terminal 24 is electrically connected to the circuit portion 22 in the circuit board 21. The case 23 is provided with an insertion hole 25 on the upper surface, and a total of twelve giant magnetoresistive elements 17 are made to face the opposing magnetic detection rotor 12 from the insertion hole 25. A lid 26 closes an opening (not shown) in the case 23. As described above, the insertion hole 25 into which the element mounting member 20 is fitted is provided in the case 23, and the first element portion 16, the second element portion 18, and the third element portion 19 are inserted through the insertion hole 25. By causing the giant magnetoresistive element 17 to face the magnetic detection rotor 12, the giant magnetoresistive element 17 in the first element portion 16, the second element portion 18 and the third element portion 19 is changed to the magnetic detection rotor. Therefore, the magnetic field lines passing through the giant magnetoresistive element 17 are increased, and the sensitivity of the output signal of the rotation sensor can be improved.

  Next, a method for assembling the rotation sensor according to the embodiment of the present invention configured as described above will be described.

  First, after depositing four giant magnetoresistive elements 17 on the upper surface of the flexible wiring board 16 a, the yoke 15 is fixed to the yoke insertion hole 14 of the holder 13.

  Next, the 1st element part 16, the 2nd element part 18, and the 3rd element part 19 are inserted in a metal mold | die, and the element mounting member 20 is formed by resin molding. At this time, the first element portion 16, the second element portion 18, and the third element portion 19 are fixed to the mold forming the element mounting member 20 at an inclination angle of 20 degrees or 25 degrees, respectively, inside the mold. A mold having an inclination angle is prepared.

  Next, the magnet 11 is inserted into the holder 13 from the lower surface of the holder 13, and the magnet 11 is press-fitted into the holder 13.

  Next, after the element mounting member 20 is fixed to the holder 13, the element mounting member 20 and the holder 13 are assembled inside the case 23.

  Next, after the circuit portion 22 is mounted on the circuit board 21, it is fixed inside the case 23.

  Next, the giant magnetoresistive element 17 and the circuit board 21 in the first element part 16, the second element part 18 and the third element part 19 of the element mounting member 20 are electrically connected by soldering or the like. Then, the circuit part 22 in the circuit board 21 and the connector terminal 24 in the case 23 are electrically connected.

  Finally, an opening (not shown) in the case 23 is closed with a lid 26.

  Next, the operation of the rotation sensor according to the embodiment of the present invention assembled as described above will be described.

  A magnetic detection rotor 12 made of a gear is provided facing the insertion hole 25 in the case 23, and the first element portion 16 and the second element portion 16 are rotated by the rotation of the convex portion 12 a of the magnetic detection rotor 12. The magnetic flux density with respect to the giant magnetoresistive element 17 in the element part 18 and the third element part 19 changes. The change in the magnetic flux density is output by the giant magnetoresistive element 17 as a sinusoidal output voltage, and the output voltage of the sinusoidal waveform is converted into an output voltage of a pulse signal by the circuit unit 22 in the circuit board 21. Then, the output voltage of this pulse signal is output to the counterpart computer (not shown) via the connector terminal 24 in the case 23 to detect the rotational speed of the magnetic detection rotor 12.

  Here, considering the case where magnetic lines of force pass through the element portion of the rotation sensor, the rotation sensor according to the embodiment of the present invention has a first element portion 16 having four giant magnetoresistive elements 17 each. The second element portion 18 and the third element portion 19 are provided, and the inclination angles of the first element portion 16 and the third element portion 19 located outside are generated from the magnet 11 as shown in FIG. The magnetic force passing through the magnetosensitive surface of the giant magnetoresistive element 17 in the first element part 16 and the third element part 19 is equal to each other in accordance with the inclination of the magnetic path of the magnetic field lines to be Thereby, as an output of the 1st element part 16 and the 3rd element part 19 which are located outside, it has the effect that an equivalent thing is obtained.

  In addition, since the inclination angle of the second element portion 18 located substantially in the center is smaller than the inclination angles of the first element portion 16 and the third element portion 19 located outside, Magnetic field lines passing through the magnetosensitive surface of the giant magnetoresistive element 17 in the first element portion 16 and the third element portion 19 and the magnetosensitive surface of the giant magnetoresistive element 17 in the second element portion 18 located substantially at the center. The projection vectors are substantially the same, which has the effect that the output signals generated from the first element part 16, the second element part 18 and the third element part 19 can be equivalent.

  The rotation sensor according to the present invention has an effect that the accuracy of rotation detection can be improved, and is useful as a rotation sensor that detects the number of rotations by a change in magnetism.

DESCRIPTION OF SYMBOLS 11 Magnet 12 Magnetic to-be-detected rotating body 13 Holder 14 Yoke insertion hole 15 Yoke 16, 18, 19 Element part 17 Magnetoresistive element 20 Element mounting member 21 Circuit board 22 Circuit part 23 Case 24 Connector terminal 25 Insertion hole

Claims (2)

Adjusting the magnetic path of the magnetic force lines generated from the magnet disposed opposite to the magnetic body to be detected, the holder containing the magnet and having the yoke insertion hole, and the yoke insertion hole of the holder. A magnetic sensing surface is provided between the yoke and the magnet and the magnetic detection rotating body so as to incline at a predetermined inclination angle from substantially perpendicular to a direction in which the magnetic detection rotating body and the magnet face each other. A circuit board provided with three element portions having four magnetoresistive elements, an element mounting member for tilting and mounting the three element portions, and a circuit portion for processing an output signal from the magnetoresistive element; A case in which the magnet, the holder, the yoke, the magnetoresistive element, the element mounting member, and the circuit board are housed and a plurality of connector terminals that are electrically connected to a circuit portion in the circuit board are provided; The serial three element portions, a rotation sensor magnetic detection target rotating body is inclined so as to form a predetermined inclination angle with respect to the direction of the magnetic path of the magnetic lines of force generated from the magnet in a direction substantially perpendicular to direction of rotation. The rotation sensor according to claim 1, wherein an insertion hole into which the element mounting member is fitted is provided in the case, and the magnetoresistive element faces the rotating body to be detected through the insertion hole.

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