JP2009097924A - Apparatus for detecting rotation angle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid disabled state of outputting index detection signal, even if the setting region of an index magnetized section is narrowed, in a rotation angle detecting apparatus. <P>SOLUTION: A magnet 50 of the rotation angle detecting apparatus has a circular magnetized section 58 in which N-poles and S-poles are alternately magnetized in the circumferential direction. A partial adjacent combination of an N-pole and S-pole constitutes a magnetic-flux-intensified combination 59, which produces a magnetic field having larger magnetic flux in each pole than the magnetic flux of the magnetic field produced by another N-pole and S-pole. The magnetic-flux-intensified combination 59 is provided at predetermined polar intervals in the circumferential direction. The entire magnetized section 58 thereby functions as a rotation angle magnetized section, while the magnetic-flux-intensified combination 59 functions as the index magnetized section. This eliminates the need for providing the setting region of the index magnetized section separately from the setting region of the rotation angle magnetized section, thereby avoiding disabled state of outputting an index detection signal, even if the setting region of the index magnetized section is narrowed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device that detects a rotation angle of a rotating body.

  2. Description of the Related Art Conventionally, a multipolar magnet that rotates integrally with a rotating body and a magnetic flux detection means that detects the magnetic flux density of a magnetic field generated from the magnet are provided. Based on the detected magnetic flux density, a pulse-like electric output is provided. 2. Description of the Related Art A rotation angle detection device as an incremental encoder that performs on / off to generate a rotation angle detection signal is known. This rotation angle detection device is mounted on, for example, a brushless motor such as a switched reluctance motor (SR motor), and the magnet is incorporated so as to rotate integrally with the rotor of the SR motor.

  According to this rotation angle detection device, the magnetized portion of the magnet is provided in an annular shape with N poles and S poles alternately magnetized in the circumferential direction, and the magnetic flux density detected by the magnetic flux detection means is: As the magnet rotates, it alternately changes to the N pole side and the S pole side. Then, according to the change in magnetic flux density from the N pole side to the S pole side and the change from the S pole side to the N pole side, the electrical output is turned on or off, and a pulsed detection signal is output. The Based on this detection signal, an electronic control unit (ECU) or the like grasps the numerical value of the rotation angle (hereinafter, the detection signal for grasping the numerical value of the rotation angle is referred to as a rotation angle detection signal).

  By the way, according to this rotation angle detecting device, when the brushless motor is started, in order to synchronize the rotation of the rotor with the energization to the stator coil at an early stage, the magnet is discontinuous separately from the continuous magnetized portion. (Hereinafter referred to as “continuous magnetized part” for detecting the rotation angle is referred to as “rotational angle magnetized part”, and “discontinuous magnetized part for synchronization”). Is called an index magnetized portion).

  Then, the magnetic flux density of the magnetic field generated from the index magnetized portion is detected by a magnetic flux detecting means different from the magnetic flux detecting means for detecting the magnetic flux density of the magnetic field generated from the rotating angle magnetized portion (hereinafter referred to as the rotational angle magnetized portion). The magnetic flux detection means for detecting the magnetic flux density of the magnetic field generated from the magnetic field is referred to as rotation angle magnetic flux detection means, and the magnetic flux detection means for detecting the magnetic flux density of the magnetic field generated from the index magnetized portion is referred to as index magnetic flux detection means).

  For example, according to the rotation angle detection device mounted on the SR motor, the index magnetized portions are coaxially arranged on the inner peripheral side of the rotation angle magnetized portion and at equal angular intervals according to the arrangement of the protrusions of the rotor. It is provided so as to be separated in the circumferential direction (for example, see Patent Document 1). This index magnetized portion is provided by being magnetized in the order of S pole, N pole, S pole in the circumferential direction (or in the order of N pole, S pole, N pole), and detected by the index magnetic flux detecting means. Changes so as to temporarily vibrate toward the S pole side and the N pole side as the magnet rotates, and this temporary vibration is periodically repeated at predetermined time intervals.

  As a result, the index magnetic flux detection means periodically turns on and off the electrical output periodically, and outputs a pulsed detection signal having a longer off period than the rotation angle detection signal. Then, using this detection signal, the ECU or the like executes control for synchronizing the SR motor (hereinafter, the detection signal for synchronizing the SR motor is referred to as an index detection signal).

  However, the area in which the index magnetized portion can be provided has become narrower with the recent progress of motor miniaturization. When the index magnetized portion becomes small, a sufficiently large magnetic flux density cannot be obtained from the index magnetized portion, and as a result, the index magnetic flux detecting means cannot output the index detection signal.

The promotion of motor miniaturization is remarkable in vehicle motors mounted on vehicles. For this reason, it is desired to avoid the inability to output the index detection signal due to the narrowing of the setting area of the index magnetized portion from the viewpoint of the motor mounting property and versatility with respect to the vehicle.
JP 2005-62120 A

  The present invention has been made to solve the above-described problems, and its object is to avoid the inability to output an index detection signal even if the setting area of the index magnetized portion is narrowed in the rotation angle detection device. There is to do.

[Means of Claim 1]
The rotation angle detection device according to claim 1 includes a multipolar magnet that rotates integrally with the rotating body, and a magnetic flux detection means that detects a magnetic flux density of a magnetic field generated from the magnet.
The magnet has an annular magnetized portion in which N poles and S poles are alternately magnetized in the circumferential direction, and a combination of some adjacent N poles and S poles is another N pole. And a magnetic flux strengthening combination part that generates a magnetic field having a higher magnetic flux density on each pole side than the magnetic flux density of the magnetic field generated from the S pole, and the magnetic flux strengthening combination parts are provided at predetermined pole intervals in the circumferential direction. .

  Accordingly, the entire magnetized portion functions as a rotation angle magnetized portion, and the magnetic flux strengthening combination portion that is a part of the magnetized portion functions as an index magnetized portion. For this reason, it is not necessary to provide the setting area for the index magnetized portion separately from the setting area for the rotation angle magnetized portion. As a result, in the rotation angle detection device, it is possible to avoid the inability to output the index detection signal even if the setting area of the index magnetized portion is narrowed.

[Means of claim 2]
The rotation angle detection apparatus according to claim 2 includes at least two magnetic flux detection means. And two magnetic flux detection means memorize | store the 1st threshold value by the side of N pole regarding the magnetic flux density, and the 2nd threshold value by the side of S pole, and based on the comparison with the detected magnetic flux density and the 1st threshold value and the 2nd threshold value, The electrical output is turned on / off so that the phases are different. In addition, one of the two magnetic flux detection means stores a third threshold value that is larger on the N pole side than the first threshold value, and a fourth threshold value that is larger on the S pole side than the second threshold value. Separately from turning on / off the electrical output based on the comparison with the first threshold and the second threshold, the electrical output is turned on / off based on the comparison between the detected magnetic flux density and the third threshold and the fourth threshold.

  As a result, the two magnetic flux detection means perform the on / off of the electrical output based on the comparison between the detected magnetic flux density and the first threshold value and the second threshold value so that the phases are different from each other. Function. In addition, one of the two magnetic flux detection means, the magnetic flux detection means performs on / off of the electrical output based on the comparison between the detected magnetic flux density and the third threshold value and the fourth threshold value, thereby the index magnetic flux detection means. Function as. That is, one magnetic flux detection means has the function of index magnetic flux detection means in addition to the function of rotation angle magnetic flux detection means.

  For this reason, the function of the rotation angle magnetic flux detection means and the function of the index magnetic flux detection means do not need to be provided in separate magnetic flux detection means, so the number of magnetic flux detection means attached to the rotation angle detection device can be reduced, and manufacturing is possible. Man-hours can be reduced.

[Means of claim 3]
According to the rotation angle detection device of the third aspect, the N pole and the S pole of the magnetic flux strengthening combination part have a smaller facing distance from the magnetic flux detection means than the other N pole and S pole.
This means shows one form for providing the magnetic flux strengthening combination part.

[Means of claim 4]
According to the rotation angle detection device of the fourth aspect, the N pole and the S pole of the magnetic flux strengthening combination part are magnetized at a higher voltage than the other N pole and S pole.
This means shows one form for providing the magnetic flux strengthening combination part.

The rotation angle detection device of the best mode includes a multipolar magnet that rotates integrally with a rotating body, and magnetic flux detection means that detects the magnetic flux density of a magnetic field generated from the magnet.
The magnet has an annular magnetized portion in which N poles and S poles are alternately magnetized in the circumferential direction, and a combination of some adjacent N poles and S poles is another N pole. And a magnetic flux strengthening combination part that generates a magnetic field having a higher magnetic flux density on each pole side than the magnetic flux density of the magnetic field generated from the S pole, and the magnetic flux strengthening combination parts are provided at predetermined pole intervals in the circumferential direction. .

  The rotation angle detecting device includes at least two magnetic flux detecting means. And two magnetic flux detection means memorize | store the 1st threshold value by the side of N pole regarding the magnetic flux density, and the 2nd threshold value by the side of S pole, and based on the comparison with the detected magnetic flux density and the 1st threshold value and the 2nd threshold value, The electrical output is turned on / off so that the phases are different. In addition, one of the two magnetic flux detection means stores a third threshold value that is larger on the N pole side than the first threshold value, and a fourth threshold value that is larger on the S pole side than the second threshold value. Separately from turning on / off the electrical output based on the comparison with the first threshold and the second threshold, the electrical output is turned on / off based on the comparison between the detected magnetic flux density and the third threshold and the fourth threshold.

  Furthermore, according to this rotation angle detection device, the N pole and the S pole of the magnetic flux strengthening combination part have a smaller facing distance to the magnetic flux detection means than the other N pole and S pole.

[Configuration of Example 1]
The configuration of the rotation angle detection device 1 according to the first embodiment will be described with reference to FIGS.
For example, as shown in FIG. 1, the rotation angle detection device 1 is mounted on the rear side of an electric motor 2 and includes an electric motor 2 and a speed reducer 3 that decelerates torque obtained from the electric motor 2 and an actuator 4 that outputs torque. Constitute.

  The actuator 4 is mounted on, for example, an automatic transmission for a vehicle (not shown) and drives various members for switching the shift range. Further, the energization control of the electric motor 2 (that is, shift range switching control by drive control of the actuator 4) is performed in accordance with a command from an electronic control unit for automatic transmission (hereinafter referred to as ECU: not shown), for example. Done. Then, the ECU executes energization control of the electric motor 2 based on inputs from the sensors (not shown) indicating the state of the range operation means operated by the occupant, the brake switch, and the rotation angle detection device 1 and the like. Output for

  The electric motor 2 is, for example, a switched reluctance motor that does not use a permanent magnet. As shown in FIGS. 1 and 2, a rotor 6 that is rotatably supported and a stator 7 that is arranged coaxially with the rotor 6. Have

The rotor 6 includes a rotor shaft 9 and a rotor core 10, and the rotor shaft 9 is rotatably supported by rolling bearings 11 and 12 arranged at both front and rear ends.
The front rolling bearing 11 is disposed on the inner periphery of the output shaft 13 of the speed reducer 3, and the output shaft 13 is rotatably supported by a metal bearing 15 disposed on the inner periphery of the front housing 14. That is, the front end of the rotor shaft 9 is rotatably supported via the metal bearing 15, the output shaft 13, and the rolling bearing 11.

Here, the support section of the metal bearing 15 overlaps the support section of the rolling bearing 11 in the axial direction. And by this overlap, it is avoided that the rotor shaft 9 inclines by the reaction force resulting from meshing of the gears of the reduction gear 3.
The rear rolling bearing 12 is supported by a rear housing 16.
The rotor core 10 is provided by laminating a large number of thin plates, and is press-fitted and fixed to the rotor shaft 9. The rotor core 10 is formed with salient poles 17 that protrude every 45 ° toward the outer periphery.

The stator 7 includes a stator core 21 and coils 22 to 33.
The stator core 21 is provided by laminating a large number of thin plates and is fixed to the rear housing 16. The stator core 21 is formed with stator teeth 37 that protrude every 30 ° toward the inner periphery, and the inner peripheral end of the stator teeth 37 faces the outer peripheral end of the salient pole 17.

  The coils 22 to 33 are wound around the stator teeth 37, and the coils 22 to 33 are wound so as to be in the U phase, the V phase, and the W phase every 30 °. For example, the coils 22, 25, 28, and 31 form a U phase, the coils 23, 26, 29, and 32 form a V phase, and the coils 24, 27, 30, and 33 form a W phase. . In this case, when the energization is switched in the order of W phase → V phase → U phase from the state shown in FIG. 2, the rotor 6 rotates counterclockwise, and when the energization is switched in the order of V phase → W phase → U phase, the rotor 6. Rotates clockwise. The rotor 6 rotates 45 ° each time the U phase, V phase, and W phase are energized.

  As shown in FIGS. 1 and 3, the speed reducer 3 includes an eccentric portion 39 that is eccentrically provided on the rotor shaft 9, and an inner gear 40 that is driven by the eccentric portion 39 and revolves around the axis of the rotor shaft 9 as a central axis. And an outer gear 41 having inner teeth meshing with the outer teeth of the inner gear 40, and transmission means 42 for transmitting the revolution of the inner gear 40 to the output shaft 13 to rotate the output shaft 13.

The eccentric portion 39 is provided integrally with the rotor shaft 9 and revolves around the axis of the rotor shaft 9 as a central axis. The eccentric portion 39 supports the inner gear 40 via a rolling bearing 44 disposed on the outer periphery, and revolves the inner gear 40 by its own revolution.
The inner gear 40 revolves with its outer teeth meshing with the inner teeth of the outer gear 41 by the revolution of the eccentric portion 39.
The outer gear 41 is fixed without rotating by press-fitting into the front housing 14 or the like.

  The transmission means 42 includes a plurality of pins 46 protruding forward from the front surface of the inner gear 40, and a flange 48 that is provided integrally with the output shaft 13 and has a plurality of pin holes 47 that are loosely fitted to the pins 46. The The flange 48 is provided at the rear end of the output shaft 13, and the pin hole 47 is provided on the same circumference centering on the axis of the output shaft 13. The axis of the output shaft 13 is coaxial with the axis of the rotor 6. Then, the transmission means 42 transmits the revolution of the inner gear 40 to the output shaft 13 through the loose fitting structure of the pin 46 and the pin hole 47, thereby rotating the output shaft 13 coaxially with the rotor 6.

  As described above, when the inner gear 40 revolves with the rotation of the rotor shaft 9, the revolution speed of the inner gear 40 is reduced more than the rotation speed of the rotor shaft 9, and the output shaft 13 has the same speed as the reduced revolution speed. Rotate. The decelerated torque is output from the output shaft 13 and used for switching the shift range.

  As shown in FIGS. 1, 3, and 4, the rotation angle detection device 1 is accommodated in the rear housing 16 and is mounted on the rear side of the electric motor 2 to detect the rotation angle of the rotor 6. In addition, the rotation angle detection device 1 includes a multipolar magnet 50 that rotates integrally with the rotor 6, two magnetic flux detection means 51 and 52 that detect the magnetic flux density of a magnetic field generated from the magnet 50, and magnetic flux detection means 51 and 52. And a substrate 53 supporting the above.

  The rotation angle detection device 1 is an incremental encoder that generates a rotation angle detection signal by turning on / off electrical output in pulses in accordance with the detected magnetic flux density. The ECU controls energization to the coils 22 to 33 based on the detection signal input from the rotation angle detection device 1.

  As shown in FIGS. 1, 2, 4 to 6, the magnet 50 is provided in an annular plate shape, is coaxially arranged with the rotor shaft 9, and is attached to the rear surface of the rotor core 10. That is, as shown in FIG. 5, a positioning hole 55 is provided on the rear surface of the rotor core 10, and a protrusion 56 that fits into the hole 55 is provided on the front surface of the magnet 50. Then, the projections 56 are fitted into the holes 55 so that the magnet 50 and the rotor core 10 are positioned, and the magnet 50 is attached to the rotor core 10.

  In addition, when the magnet 50 is mounted on the rotor core 10, when the influence of the magnetic force from the rotor core 10 to the magnet 50 is large, a nonmagnetic film member is interposed between the magnet 50 and the rotor core 10. When the influence of the magnetic force on the magnet 50 is small, the magnet 50 and the rotor core 10 are in direct contact with each other.

  Furthermore, the joining of the magnet 50 and the rotor core 10 is maintained by the magnetic force by, for example, partially magnetizing the front surface of the magnet 50. In addition, the bonding between the magnet 50 and the rotor core 10 may be maintained by applying an adhesive and using the adhesive force of the adhesive regardless of the magnetic force. The magnet 50 is, for example, a neodymium magnet that is one of rare earth magnets.

  In such a magnet 50, as shown in FIG. 6, the magnetized portion 58 as a detecting portion used for detecting the rotation angle is continuously attached with an N pole and an S pole alternately in the circumferential direction on the outer periphery of the rear surface. It is magnetized and provided in an annular shape. Further, a combination of some adjacent N poles and S poles is a magnetic flux strengthening combination part that generates a magnetic field having a higher magnetic flux density on each pole side than the magnetic flux density of the magnetic fields generated from other N and S poles. 59. And this magnetic flux reinforcement | strengthening combination part 59 is provided at the predetermined | prescribed pole space | interval in the circumferential direction.

  Here, the portion forming the N pole and the S pole of the magnetic flux strengthening combination portion 59 is provided so as to bulge rearward from the portion forming the other N pole and S pole (see FIG. 4). That is, the N pole and S pole of the magnetic flux strengthening combination part 59 are provided so that the axial facing distance to the magnetic flux detection means 51 and 52 is smaller than the other N pole and S pole. Thereby, the magnetic field generated from the N pole and the S pole of the magnetic flux strengthening combination part 59 is detected by the magnetic flux detection means 51 and 52 as a magnetic flux density larger than the magnetic field generated from the other N pole and S pole.

  The magnetized portion 58 has 48 poles in which the N pole and the S pole are repeated at intervals of 7.5 °, and the magnetic flux strengthening combination portion 59 makes a round of energization of the U phase, the V phase, and the W phase 45. There are 16 poles provided at intervals of °.

  As shown in FIGS. 1, 2, and 4, the magnetic flux detection means 51 and 52 are mounted on the front surface of the substrate 53 and face the magnetized portion 58 in the axial direction. The magnetic flux detection means 51 and 52 generate, for example, an output corresponding to the amount of magnetic flux that passes through the Hall element that detects the magnetic flux density, and an electric power according to the output of the Hall element (that is, the detected magnetic flux density). This is a Hall IC composed of a circuit that performs on / off of the dynamic output.

  And the magnetic flux detection means 51 and 52 memorize | store the 1st threshold value by the side of N pole regarding the magnetic flux density, and the 2nd threshold value by the side of S pole, and based on the comparison with the detected magnetic flux density and the 1st, 2nd threshold value, Turns on / off electrical output. Here, the first and second threshold values are stored as numerical values having the same absolute value and opposite signs. The first and second threshold values are set as threshold values for the magnetic flux density of the magnetic field generated from all the N and S poles including the magnetic flux strengthening combination unit 59. That is, the first and second threshold values are set as threshold values in a range of absolute values with a small magnetic flux density.

  Thereby, when the magnet 50 rotates, the magnetic flux density detected by the magnetic flux detection means 51 and 52 alternately changes in a sine wave shape to the N pole side and the S pole side as shown in FIG. For example, when the magnetic flux density changes from the S pole side to the N pole side and exceeds the first threshold value, the magnetic flux detection means 51 and 52 turn on the electrical output, and the magnetic flux density changes from the N pole side to the S pole side. If it changes and exceeds a 2nd threshold value, the magnetic flux detection means 51 and 52 will turn off an electrical output.

  As a result, the magnetic flux detection means 51 and 52 each output a pulse-shaped detection signal having a period of 15 ° as shown in the A phase and the B phase in FIG. Here, the magnetic flux detection means 51 and 52 are arranged so as to be shifted in the circumferential direction so that the detection signals output from each of them are different in phase by 3.75 °. Then, the ECU grasps the numerical value of the rotation angle of the rotor 6 based on the detection signals having two different phases (hereinafter, two values output from the magnetic flux detection means 51 and 52 and used for grasping the numerical value of the rotation angle). The detection signal is called a rotation angle detection signal).

  Further, one of the magnetic flux detection means 51 and 52 stores the third threshold value that is larger on the N pole side than the first threshold value and the fourth threshold value that is larger on the S pole side than the second threshold value. Separately from the on / off of the electrical output based on the comparison with the first and second thresholds, the electrical output is turned on / off based on the comparison between the detected magnetic flux density and the third and fourth thresholds. Here, the third and fourth threshold values are stored as numerical values having the same absolute value and opposite signs.

  The third and fourth threshold values are set as threshold values for the magnetic flux density of the magnetic field generated only from the N pole and S pole of the magnetic flux strengthening combination unit 59. That is, the third and fourth threshold values are set as threshold values in an absolute value range where the magnetic flux density is large.

  Thus, when the magnet 50 rotates, the magnetic flux density detected by the magnetic flux detection means 51 is such that the peak of the sine wave temporarily increases to the N pole side and the S pole side as shown in FIG. To change. For example, when the magnetic flux density greatly changes from the S pole side to the N pole side and exceeds the third threshold value, the magnetic flux detection means 51 separates the electrical output on due to the fact that the first threshold value is exceeded. Turn on automatic output. Further, when the magnetic flux density greatly changes from the N pole side to the S pole side and exceeds the fourth threshold value, the magnetic flux detection means 51 separates the third threshold value from the off of the electrical output due to exceeding the second threshold value. Turns off the electrical output that was turned on when exceeded.

  As a result, as shown in the Z phase of FIG. 8, the magnetic flux detection means 51 outputs a pulse-like detection signal with 45 ° as one cycle of energization of the U phase, V phase, and W phase. The ON period of this detection signal is 7.5 °, which is the same as the rotation angle detection signal. Then, the ECU executes control for synchronizing the electric motor 2 based on the detection signal that is turned on at a cycle of 45 ° (hereinafter, output from the magnetic flux detecting means 51 to synchronize the electric motor 2). A detection signal used for control is called an index detection signal).

[Effect of Example 1]
According to the rotation angle detection device 1 of the first embodiment, the magnet 50 has the annular magnetized portion 58 provided by alternately magnetizing the N pole and the S pole in the circumferential direction, and some adjacent N poles are provided. The combination of the pole and the S pole constitutes a magnetic flux strengthening combination part 59 that generates a magnetic field having a magnetic flux density larger on each pole side than the magnetic flux density of the magnetic field generated from the other N pole and S pole. 59 are provided at predetermined pole intervals in the circumferential direction.

  Accordingly, the entire magnetized portion 58 functions as a rotation angle magnetized portion for grasping the numerical value of the rotation angle, and the magnetic flux strengthening combination portion 59 that is a part of the magnetized portion 58 synchronizes the electric motor 2. It functions as an index magnetization part for taking. For this reason, it is not necessary to provide the setting area for the index magnetized portion separately from the setting area for the rotation angle magnetized portion. As a result, in the rotation angle detection device 1, it is possible to avoid the inability to output the index detection signal even if the setting area of the index magnetized portion is narrowed.

  The magnetic flux detection means 51 and 52 store the first threshold value on the N pole side and the second threshold value on the S pole side regarding the magnetic flux density, and based on the comparison between the detected magnetic flux density and the first and second threshold values, The electrical output is turned on / off so that the phases are different. Further, the magnetic flux detection means 51 stores a third threshold value that is larger on the N pole side than the first threshold value, and a fourth threshold value that is larger on the S pole side than the second threshold value, for comparison with the first and second threshold values. Separately from the on / off of the electrical output based on the electrical output, the electrical output is turned on / off based on the comparison between the detected magnetic flux density and the third and fourth threshold values.

  As a result, the magnetic flux detection means 51 and 52 output the rotation angle detection signal by executing on / off of the electrical output in different phases based on the comparison between the detected magnetic flux density and the first and second threshold values. It functions as a rotating angle magnetic flux detecting means. Moreover, the magnetic flux detection means 51 functions as an index magnetic flux detection means for outputting an index detection signal by executing on / off of the electrical output based on the comparison between the detected magnetic flux density and the third and fourth threshold values. That is, the magnetic flux detection means 51 has a function of the index magnetic flux detection means in addition to the function of the rotation angle magnetic flux detection means.

  For this reason, since it is not necessary to provide the function of the rotation angle magnetic flux detection means and the function of the index magnetic flux detection means in separate Hall ICs, the number of Hall ICs to be mounted on the rotation angle detection device 1 can be reduced, and the number of manufacturing steps can be reduced. Can be lowered.

[Modification]
According to the rotation angle detection device 1 of the first embodiment, the magnetic flux strengthening combination unit 59 makes the facing distance between the N pole and S pole and the magnetic flux detection means 51 and 52 smaller than the other N pole and S pole. However, the magnetic flux strengthening combination unit 59 may be set by magnetizing the N pole and the S pole of the magnetic flux strengthening combination unit 59 at a higher voltage than the other N poles and S poles.

  Further, according to the rotation angle detection device 1 of the first embodiment, the magnetic flux detection means 51, 52 turns on the electrical output when the magnetic flux density changes from the S pole side to the N pole side and exceeds the first threshold value, When the magnetic flux density changes from the N pole side to the S pole side and exceeds the second threshold value, the rotation angle detection signal is output by turning off the electrical output. However, the magnetic flux density is changed from the S pole side to the N pole side. When it changes and exceeds the first threshold, the electrical output is turned off, and when the magnetic flux density changes from the N pole side to the S pole side and exceeds the second threshold value, the electrical output is turned on to output the rotation angle detection signal. You may let them.

  Further, according to the rotation angle detection device 1 of the first embodiment, the magnetic flux detection means 51 turns on the electrical output when the magnetic flux density greatly changes from the S pole side to the N pole side and exceeds the third threshold value, and the magnetic flux is turned on. When the density greatly changes from the N pole side to the S pole side and exceeds the fourth threshold value, the index detection signal is output by turning off the electrical output, but the magnetic flux density increases from the S pole side to the N pole side. When the change exceeds the third threshold, the electrical output is turned off. When the magnetic flux density changes greatly from the N pole side to the S pole side and exceeds the fourth threshold, the electrical output is turned on to output the index detection signal. You may let them.

  In addition, the actuator 4 having the rotation angle detection device 1 of the first embodiment as a constituent element is mounted on an automatic transmission for a vehicle and used for switching a shift range. The application of the rotation angle detection device 1 is as follows. The rotation angle of the rotating body may be detected in other applications without being limited to the shift range switching.

  Moreover, although the electric motor 2 whose rotation angle is detected by the rotation angle detection device 1 of the first embodiment is an SR motor (switched reluctance motor), the rotation angle detection device 1 includes a synchronous reluctance motor, a brushless DC motor, The rotation angle of other types of motors such as a surface magnet type synchronous motor and an embedded magnet type synchronous motor can also be detected.

It is sectional drawing of an actuator. It is a front view of an electric motor. It is the disassembled perspective view which looked at the reduction gear from the front side. It is a fragmentary perspective view of a rotation angle detection apparatus. It is explanatory drawing which shows the assembly | attachment of a magnet. (A) is explanatory drawing which shows the magnetization state of a magnet, (b) is AA sectional drawing of (a). (A) is a wave form diagram which shows the change of the magnetic flux density detected by one magnetic flux detection means, (b) is a wave form diagram which shows the change of the magnetic flux density detected by the other magnetic flux detection means. (A) is an output waveform diagram of a rotation angle detection signal and an index detection signal during reverse rotation, and (b) is an output waveform diagram of a rotation angle detection signal and an index detection signal during forward rotation.

Explanation of symbols

1 Rotation angle detection device 6 Rotor (rotating body)
50 Magnet 51 Magnetic flux detection means 52 Magnetic flux detection means 58 Magnetized part 59 Magnetic flux strengthening combination part

Claims (4)

A multipolar magnet that rotates integrally with the rotating body;
Magnetic flux detection means for detecting the magnetic flux density of the magnetic field generated from the magnet,
The magnet has an annular magnetized portion provided by alternately magnetizing N and S poles in the circumferential direction;
Some of the combinations of N poles and S poles adjacent to each other constitute a magnetic flux strengthening combination part that generates a magnetic field having a larger magnetic flux density on each pole side than the magnetic flux density of the magnetic fields generated from other N and S poles. ,
The rotation angle detecting device characterized in that the magnetic flux strengthening combination portions are provided at predetermined pole intervals in the circumferential direction. The rotation angle detection device according to claim 1,
Comprising at least two magnetic flux detection means;
The two magnetic flux detection means are:
Storing a first threshold value on the N pole side and a second threshold value on the S pole side with respect to the magnetic flux density;
Based on the comparison between the detected magnetic flux density and the first threshold value and the second threshold value, on / off of the electrical output is executed so that the phases are different from each other,
One of the two magnetic flux detection means, the magnetic flux detection means,
Storing a third threshold value larger on the N pole side than the first threshold value and a fourth threshold value larger on the S pole side than the second threshold value;
Apart from turning on / off the electrical output based on the comparison between the first threshold and the second threshold, the electrical output is turned on / off based on the comparison between the detected magnetic flux density and the third threshold and the fourth threshold. A rotation angle detection device characterized in that the rotation angle detection device is executed. In the rotation angle detection device according to claim 1 or 2,
The rotation angle detection device according to claim 1, wherein the N pole and the S pole of the magnetic flux strengthening combination part have a smaller facing distance from the magnetic flux detection means than the other N pole and S pole. In the rotation angle detection device according to claim 1 or 2,
The rotation angle detecting device, wherein the N pole and S pole of the magnetic flux strengthening combination part are magnetized at a higher voltage than the other N pole and S pole.

Images