JP2020054184A - motor - Google Patents

Abstract

To provide a motor capable of reducing deterioration of rotational accuracy of a FG signal, even when eccentricity occurs during rotation of the rotor.SOLUTION: A motor comprises a rotor including a lidded cylindrical rotor core having a shaft extending along the medial axis, and a hollow cylindrical magnet 6 provided in the inner peripheral side of the rotor core, a detection element for detecting flux density of the magnet, and a signal output part for outputting a signal relevant to the revolution of the rotor on the basis of the flux density. The magnet includes a first magnetization boundaries 16a, 16b where the first poles 6s and the second poles 6n are placed alternately in the hoop direction, and the first poles and the second poles are placed in the inverse direction of the rotation direction and second magnetization boundaries 17a, 17b where the second poles and the first poles are placed in the inverse direction of the rotation direction, and in the plan view from the direction along the medial axis, the first magnetization boundaries are located on the magnet center axis passing the center of the magnet and a straight passing the center axis.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a motor.

  In recent years, brushless DC motors have been used as motors mounted on electronic devices. Patent Literature 1 below discloses a technique of performing rotation control in an outer rotor type brushless DC motor by using an FG signal relating to the rotation speed of a rotor. In this brushless DC motor, magnetism from a magnet provided on a rotor is detected by a sensor, and an FG signal is generated based on the detection result.

JP 2010-41872 A

  The rotor is configured by attaching a magnet to the inner periphery of the rotor core. However, it is difficult to accurately attach the rotor core and the magnet, and the center axes of the rotor core and the magnet are shifted from each other. As described above, the magnet having a displacement with respect to the rotor core is eccentric when the rotor rotates. Since the position of the magnet rotating in the eccentric state with respect to the sensor varies in the radial direction, the rotation accuracy of the rotor is good, but only the rotation accuracy of the FG signal is deteriorated.

  In view of the above circumstances, it is an object of the present invention to provide a motor that can reduce deterioration in rotation accuracy of an FG signal even when eccentricity occurs during rotation of a rotor.

  One aspect of the motor of the present invention is a rotor having a covered cylindrical rotor core having a shaft extending along a central axis, a hollow cylindrical magnet provided on an inner peripheral side of the rotor core, and a rotor having the magnet. A detection element that detects a magnetic flux density; and a signal output unit that outputs a signal related to a rotation speed of the rotor based on the magnetic flux density. The magnet has a first pole and a second pole along a circumferential direction. The first pole and the second pole, which are arranged alternately and line up in the rotation direction from the rear in the rotation direction to the first magnetization boundary of the first pole and the second pole, and A first magnetized boundary including a first magnetized boundary and a center axis passing through the center of the magnet when viewed in a plan view from a direction along the central axis. It is located on a straight line passing through.

  According to one aspect of the present invention, there is provided a motor capable of reducing deterioration of rotation accuracy of an FG signal even when eccentricity occurs during rotation of a rotor.

It is sectional drawing of a motor. It is a top view of the magnet which comprises a rotor. FIG. 4 is a diagram illustrating a relationship between a magnetic flux density and an FG signal. FIG. 4 is a diagram illustrating a positional relationship between a detection element and a magnet in a rotor without eccentricity. It is a top view of a 1st rotor. It is a top view of a 2nd rotor. It is a top view of a 3rd rotor. FIG. 9 is a diagram illustrating a change in a positional relationship between a magnet and a detection element when a third rotor rotates. It is a figure explaining a shake detection process. It is a figure explaining a marking process. It is a figure explaining a magnetization process. It is a figure showing appearance of a motor. It is a horizontal sectional view of a vehicle headlamp.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the technical idea of the present invention.

  The motor according to the present embodiment relates to a motor used to drive a rotary reflector that forms a light distribution pattern incorporated in a vehicle headlamp.

  FIG. 1 is a cross-sectional view of the motor according to the present embodiment. The motor of the present embodiment is an outer rotor type motor. As shown in FIG. 1, the motor 10 of the present embodiment includes a stator 1, a rotor 2, a bearing 3, a circuit board 4, and a detection element 5. The motor 10 of the present embodiment is an outer rotor type motor in which a rotor 2 is arranged on an outer peripheral side of a stator 1.

  In the following drawings including FIG. 1, the scale and the number of the actual structure may be different from those of the actual structure in order to make each structure easy to understand. Unless otherwise specified, a direction parallel to the central axis J is simply called “axial direction”, a radial direction about the central axis J is simply called “radial direction”, and a circumferential direction about the central axis J is That is, the circumference of the central axis J is simply referred to as “circumferential direction”. Further, in the following description, “in plan view” means a state viewed from the axial direction.

  The stator 1 has a substantially cylindrical bearing holding portion 1a centered on the center axis J, a stator core 1b mounted radially outside the bearing holding portion 1a, and a coil 1c mounted on the stator core 1b. The bearing holding part 1a supports two bearings 3 which are part of the bearing mechanism in the axial direction. The stator core 1b is formed as a laminated body in which a plurality of plate-like bodies are laminated. A plurality of teeth as respective magnetic poles are arranged at predetermined intervals in a circumferential direction on an outer peripheral portion of the stator core 1b. A coil 1c is wound around an arm constituting a magnetic circuit inside each tooth via an insulator (not shown). Thus, the stator 1 in which the coil 1c is wound around the stator core 1b is configured.

  The rotor 2 is rotatably supported on the stator 1 about a central axis J via a bearing 3. The rotor 2 is a substantially cylindrical metal rotor core 8 having a center axis J as a center and made of a magnetic material. The rotor 2 is provided inside the sidewall of the rotor core 8 (that is, on the inner peripheral side), and the coil of the stator 1 is provided. The magnet 6 includes a magnet 6 arranged to face the first core 1c and a shaft 9 extending from the rotor core 8 along the central axis J. The center of the shaft 9 coincides with the central axis J. The shaft 9 may be made of the same member as the rotor core 8, or may be made of a member different from the rotor core 8. A rotating body (not shown) rotated by a motor 10 is attached to the shaft 9. The motor 10 controls rotation of a rotating body attached to the shaft 9.

  The rotor 2 of the present embodiment is configured by fixing the magnet 6 to the inner peripheral side of the rotor core 8 via the adhesive 7. As a result, in the rotor 2 of the present embodiment, the rotor core 8 and the magnet 6 can be easily fixed, so that the manufacturing process of the rotor 2 is easy.

FIG. 2 is a plan view of a magnet constituting the rotor.
As shown in FIG. 2, the magnet 6 has a substantially hollow cylindrical shape extending along the magnet center axis 6C, and S poles (first poles) 6s and N poles (second poles) 6n are alternately arranged along the circumferential direction. They are arranged two by two. The magnet center axis 6C passes through the center of gravity of the magnet 6. In the magnet 6 of the present embodiment, a plurality of magnetized boundaries 15 are provided at 90 ° intervals in the circumferential direction. The magnetized boundary portion 15 forms a boundary between the S pole 6s and the N pole 6n.
The rotor 2 of the present embodiment forms a four-pole rotor. The rotor 2 of the present embodiment rotates in a rotation direction R that is counterclockwise when viewed in a plan view.

  The plurality of magnetized boundary portions 15 include a pair of first magnetized boundary portions 16a and 16b and a pair of second magnetized boundary portions 17a and 17b. The first magnetized boundary portions 16a and 16b are magnetized boundaries in which the S pole 6s and the N pole 6n are arranged in a direction opposite to the rotation direction R of the magnet 6. The second magnetized boundary portions 17a and 17b are magnetized boundaries in which the N pole 6n and the S pole 6s are arranged in a direction opposite to the rotation direction R of the magnet 6.

  Returning to FIG. 1, the circuit board 4 is held by being inserted into the bearing holding portion 1a of the stator 1. The circuit board 4 has a substantially annular shape, and is electrically connected to a lead (not shown) drawn from the coil 1 c of the stator 1, and controls the rotation of the rotor 2. On the circuit board 4, for example, an integrated circuit and a capacitor (not shown) are mounted in addition to the detection element 5.

  The motor 10 of the present embodiment generates a magnetic field alternately from each tooth by applying an alternating current to the coil 1c, and generates an attractive force and a repulsive force between the magnetic field from each tooth and the magnet 6. Thereby, the rotor 2 rotates around the central axis J.

  In the present embodiment, the detection element 5 is provided on the upper surface 4a of the circuit board 4 facing the rotor 2. The detection element 5 is configured by a Hall element such as a Hall IC. The detection element 5 detects the magnetic flux density of the magnet 6 in the rotating rotor 2 and transmits the detection result to the circuit board 4. The circuit board 4 includes an output unit 4b that outputs an FG signal based on the magnetic flux density of the magnet 6. The FG signal is a signal containing a frequency component corresponding to the rotation speed of the rotor 2 and is output from the output unit 4b of the circuit board 4. The FG signal is used for light distribution control in a rotating reflector 124 (see FIG. 9) described later.

Here, the relationship between the magnetic flux density and the FG signal will be described with reference to the drawings.
FIG. 3 is a diagram showing the relationship between the magnetic flux density and the FG signal. The upper part of FIG. 3 shows the magnetic flux density detected by the detecting element 5, the horizontal axis corresponds to the rotation angle of the motor (unit is deg), and the vertical axis corresponds to the magnetic flux density (unit is mT). The lower part of FIG. 3 shows an FG signal output based on the magnetic flux density.

  First, the magnetic flux density will be described. When the magnetic field lines from the S pole 6 s of the magnet 6 are detected by the detection element 5, the first detection value of the magnetic flux density by the detection element 5 becomes “negative”. Further, when the magnetic field lines from the N pole of the magnet 6 are detected by the detection element 5, the second detection value of the magnetic flux density by the detection element 5 becomes “positive”. Accordingly, the position of the magnetic pole of the magnet 6 with respect to the detection element 5 changes with the rotation of the rotor 2, so that the magnetic flux density is defined by a periodically changing waveform as shown in FIG.

  Before and after the first magnetized boundary portions 16a and 16b pass through the detection element 5 when the rotor rotates, the magnetic pole detected by the detection element 5 switches from the S pole 6s to the N pole 6n. That is, when the first magnetized boundary portions 16a and 16b pass through the detection element 5, the magnetic flux density of the detection element 5 changes from the first detection value (negative value) to the second detection value (positive value).

  On the other hand, before and after the second magnetized boundary portions 17a and 17b pass through the detection element 5 during rotation of the rotor, the magnetic pole detected by the detection element 5 switches from the N pole 6n to the S pole 6s. That is, when the second magnetized boundary portions 17a and 17b pass through the detection element 5, the magnetic flux density of the detection element 5 changes from the second detection value (positive value) to the first detection value (negative value).

  The circuit board 4 of the present embodiment generates and outputs the FG signal according to the switching timing at which the magnetic flux density transmitted from the detection element 5 changes from the first detection value to the second detection value by the output unit 4b. I do. In other words, it can be said that the FG signal is generated in accordance with the timing at which the first magnetized boundary portions 16a and 16b pass through the detection element 5.

  The FG signal falls from “HIGH” to “LOW” at the timing when the first magnetization boundaries 16 a and 16 b pass through the detection element 5, and the timing when the second magnetization boundaries 17 a and 17 b pass through the detection element 5. Is defined by a pulse rising from “LOW” to “HIGH”.

As described above, the rotor 2 of the present embodiment is configured by fixing the magnet 6 to the inner peripheral side of the rotor core 8 via the adhesive 7 as shown in FIG.
However, the thickness of the adhesive 7 tends to be non-uniform in some places due to a change in volume before and after curing. Therefore, in the rotor 2 of the present embodiment, the magnet 6 is displaced from the rotor core 8. Specifically, in the rotor 2 of the present embodiment, the center axis J of the rotor core 8 and the magnet center axis 6C of the magnet 6 are arranged in different places. Therefore, in the rotor 2 of the present embodiment, the magnet 6 rotates in an eccentric state with respect to the shaft 9 (center axis J) which is the rotation axis of the rotor 2. Hereinafter, the rotor 2 that rotates with the magnet 6 eccentric will be referred to as an “eccentric rotor”, and the rotor 2 that rotates in an ideal state where the magnet will not eccentric will be referred to as a “non-eccentric rotor”. To

  Here, a rotor without eccentricity will be considered for comparison. In other words, the rotor without eccentricity means a state in which the thickness of the adhesive 7 is uniform, and the center axis J of the rotor core 8 and the magnet center axis 6C of the magnet 6 coincide. Such a rotor without eccentricity rotates with the center axis J of the rotor core 8 and the magnet center axis 6C of the magnet 6 aligned. In this case, in a rotor without eccentricity, the magnet 6 rotates around the magnet center axis 6C.

  FIG. 4 is a diagram showing a positional relationship between a detection element and a magnet in a rotor without eccentricity. FIG. 4 shows a change in the positional relationship between the detection element 5 and the magnet 6 when the rotation angle of the rotor 12 without eccentricity changes from 0 ° to 90 ° at a time. In FIG. 4, the position of the detection element 5 is moved outward in the radial direction of the magnet 6 for the sake of clarity.

  In FIG. 4, the rotation angle of the rotor 12 where the first magnetized boundary portion 16a of the magnet 6 is located on a line passing through the detection element 5 and the central axis J (hereinafter referred to as a reference line K) is set to 0 °. When the rotation angle of the rotor 12 is 0 °, the state where the first magnetized boundary portion 16a is located on the reference line K is that the magnetic flux density in the detection element 5 is changed from the first detection value (negative) to the second detection value (positive). ). In the rotor 12 having no eccentricity, the positional relationship between the center axis J (magnet center axis 6C) and the detecting element 5 is constant without change during rotation.

  As shown in FIG. 4, in the rotor 12 having no eccentricity, the magnet 6 is turned on after the first magnetized boundary portion 16 a passes the reference line K after the first magnetized boundary portion 16 a passes the reference line K. Rotate 180 °. Similarly, after the first magnetized boundary portion 16b passes through the reference line K, the magnet 6 rotates 180 ° before the first magnetized boundary portion 16a passes through the reference line K. Therefore, in the rotor 12 without eccentricity, the magnetic flux density in the detecting element 5 switches from “negative: first detected value” to “positive: second detected value” every time the rotor 12 rotates by 180 °.

  According to the rotor 12 having no eccentricity as described above, the magnetic flux density changes at a constant cycle (a cycle of half a rotation of the rotor). Therefore, the rotation accuracy of the FG signal output based on the magnetic flux density also increases. Here, that the rotation accuracy of the FG signal is high means a state in which the time of one pulse of the FG signal shown in FIG. 3 is constant.

  Therefore, if the rotor 12 has no eccentricity, it is possible to generate an FG signal with high rotation accuracy. On the other hand, in a rotor with eccentricity, the period of the magnetic flux density fluctuates as described later, so that there is a problem that the rotation accuracy of the FG signal output based on the magnetic flux density is reduced.

  On the other hand, the present inventors set the eccentric rotor 2 by appropriately setting the positional relationship between the magnet center axis 6C, the center axis J, and the first magnetized boundary portions 16a and 16b. However, it has been found that deterioration of the rotation accuracy of the FG signal can be reduced. Then, the rotor 2 of the present embodiment was completed. That is, according to the rotor 2 of the present embodiment, as described later, the magnet 6 rotates in an eccentric state, that is, even if the rotor 2 has an eccentricity, it is possible to reduce the deterioration of the rotation accuracy of the FG signal. is there.

  Here, the first rotor, the second rotor, and the third rotor having different eccentric directions of the magnet center axis 6C with respect to the center axis J will be described as examples. The first rotor, the second rotor, and the third rotor have a configuration in which the position of the magnet 6 having a rotation angle of 0 ° in the non-eccentric rotor 12 shown in FIG. .

  FIG. 5A is a plan view of the first rotor. As shown in FIG. 5A, the first rotor 2A is eccentric to one side (for example, the lower left side) in an oblique direction in which the magnet central axis 6C intersects the reference axis K at an angle of 45 ° with the central axis J. ing. The magnet 6 rotates counterclockwise around the central axis J.

  Here, a first imaginary line L1 connecting the radially inner end face 16a1 of the first magnetized boundary portion 16a and the central axis J, a radially inner end face 16b1 of the first magnetized boundary portion 16b and the central axis J And a second imaginary line L2 connecting the two.

Then, the second angle formed between the virtual line L2 is positioned in the clockwise direction with respect to the first imaginary line L1 and the first virtual line L1 as the first angle theta _1, the first virtual line L1 and the first virtual the second is the angle between the virtual line L2 is the second angle theta ₂ in the counterclockwise direction with respect to the line L1. The first angle theta ₁ less than 180 °, the second angle theta ₂ greater than 180 °.

The first angle θ ₁ corresponds to a first rotation angle of the first rotor 2A until the first magnetized boundary portions 16a and 16b pass through the detection element 5, respectively. The second angle theta _2, the first magnetic boundary portion 16b, 16a corresponds to the second rotation angle in the first rotor 2A to pass through the detecting element 5, respectively.

  When the difference between the first rotation angle and the second rotation angle occurs in this way, the first period of the first magnetic flux density generated by rotating the first rotor 2A by the first rotation angle and the first rotor 2A A difference is generated between the second period of the second magnetic flux density generated by rotating by the second rotation angle. Specifically, the first cycle in which the rotation angle (first rotation angle) of the first rotor 2A is small is shorter than the second cycle in which the rotation angle (second rotation angle) of the first rotor 2A is large.

  When a difference occurs between the periods of the first magnetic flux density and the second magnetic flux density, the pulse periods of the FG signals output based on the first magnetic flux density and the second magnetic flux density do not become constant. That is, a difference occurs in the time of one pulse of the FG signal output based on the first magnetic flux density and the second magnetic flux density. Therefore, the rotation accuracy of the generated FG signal is reduced.

  In the first rotor 2A, the eccentric direction of the magnet central axis 6C with respect to the central axis J has been described as being diagonally lower left, but the eccentric direction of the magnet central axis 6C is not limited to this. That is, the eccentric direction of the magnet center axis 6C is not particularly limited as long as it is a direction intersecting the reference line K at an angle other than 45 ° (excluding 90 ° described later). For example, the eccentric direction of the magnet center axis 6C with respect to the center axis J may be diagonally upper right, diagonally lower right, or diagonally upper left.

  Therefore, if the structure of the first rotor 2A is adopted as the rotor 2 of the present embodiment, the accuracy of the generated FG signal is reduced due to the influence of the eccentricity. Therefore, the rotor 2 of the present embodiment has a configuration different from that of the first rotor 2A.

  FIG. 5B is a plan view of the second rotor. As shown in FIG. 5B, in the second rotor 2 </ b> B, the magnet center axis 6 </ b> C intersects (orthogonally) with the reference axis K at an angle of 90 ° with respect to the center axis J at one side (for example, the lower side) in the vertical direction. Eccentric. The magnet 6 rotates counterclockwise around the central axis J.

Similarly to the aforementioned first rotor 2A in the second rotor 2B, defining the first virtual line L1, the second virtual line L2, the first angle theta ₁ and the second angle theta _2. As shown in FIG. 5B, the first angle theta ₁ is less than 180 °, the second angle theta ₂ greater than 180 °.

  As shown in FIG. 5B, a difference occurs between the first rotation angle and the second rotation angle also in the second rotor 2B, so that a difference occurs between the periods of the first magnetic flux density and the second magnetic flux density. Therefore, the pulse periods of the FG signals output based on the first magnetic flux density and the second magnetic flux density do not become constant. That is, a difference occurs in the time of one pulse of the FG signal output based on the first magnetic flux density and the second magnetic flux density. Therefore, the rotation accuracy of the generated FG signal is reduced.

  In the second rotor 2B, the eccentric direction of the magnet central axis 6C with respect to the central axis J has been described as a lower side, but the eccentric direction of the magnet central axis 6C is not limited to this. That is, the eccentric direction of the magnet center axis 6C with respect to the center axis J may be on the upper side.

  Therefore, if the structure of the second rotor 2B is adopted as the rotor 2 of the present embodiment, the rotation accuracy of the generated FG signal is reduced due to the influence of the eccentricity. Therefore, the rotor 2 of the present embodiment has a configuration different from that of the second rotor 2B.

  FIG. 5C is a plan view of the third rotor. As shown in FIG. 5C, in the third rotor 2C, the magnet center axis 6C is eccentric to one side (for example, the left side) in the direction along the reference line K with respect to the center axis J. The magnet 6 rotates counterclockwise around the central axis J. Note that the rotor 2 of the present embodiment employs the structure of the third rotor 2C. Hereinafter, the reason for employing the third rotor 2C will be described.

  Specifically, in the third rotor 2C, the first magnetized boundary portions 16a and 16b are located on a straight line L passing through the magnet center axis 6C and the center axis J. That is, the first magnetized boundary portions 16a and 16b, the magnet central axis 6C, and the central axis J are arranged on the straight line L.

  In the present embodiment, the first magnetized boundary portions 16a, 16b have a predetermined width in the circumferential direction. Therefore, in the present embodiment, the expression that the first magnetized boundary portions 16a and 16b, the magnet center axis 6C, and the center axis J are aligned on the straight line L means that the first magnetized boundary portions 16a and 16b are aligned with the center in the circumferential direction. The state is not limited to the state where L completely coincides, and includes, for example, a state where at least a part of the first magnetized boundary portions 16a and 16b overlaps the straight line L in the circumferential direction.

Similarly to the aforementioned first rotor 2A and the second rotor 2B in the third rotor 2C, defining the first virtual line L1, the second virtual line L2, the first angle theta ₁ and the second angle theta _2. As shown in FIG. 5C, the third rotor 2C, since the first magnetic boundary portion 16a, 16b and the central axis J are aligned on a straight line, the first angle theta ₁ and the second angle theta ₂ is 180 °, respectively .

  In the third rotor 2C, the rotor rotation angle (first rotation angle) until the first magnetization boundary portions 16a and 16b sequentially pass through the detection element 5, and the first magnetization boundary portions 16b and 16a determine the detection element 5. The rotor rotation angle (the second rotation angle) before passing in order is 180 °.

  FIG. 6 is a diagram showing a change in the positional relationship between the magnet and the detection element when the third rotor rotates. As shown in FIG. 6, in the third rotor 2 </ b> C, although the magnet 6 rotates in an eccentric state, each time the rotor rotates 180 °, the first magnetization boundary portions 16 a and 16 b pass through the detection element 5. Become like

  Therefore, the periods of the first magnetic flux density and the second magnetic flux density generated each time the third rotor 2C makes a half rotation (180 ° rotation) are equal to each other. Therefore, the pulse period (one pulse time) of the FG signal output based on the first magnetic flux density and the pulse period (one pulse time) of the FG signal output based on the second magnetic flux density become constant. . That is, since there is no difference in the time of one pulse of the FG signal output based on the first magnetic flux density and the second magnetic flux density, the FG signal with high rotational accuracy is not affected by the eccentricity of the magnet 6. Can be output.

  In the third rotor 2C, the eccentric direction of the magnet central axis 6C with respect to the central axis J has been described as the left side in the direction along the reference line K, but the eccentric direction of the magnet central axis 6C is not limited to this. That is, the eccentric direction of the magnet center axis 6C is not particularly limited as long as it is a direction along the reference line K, and may be, for example, the right side in the direction along the reference line K.

For the reasons described above, the rotor 2 of the present embodiment employs the structure of the third rotor 2C. That is, in the rotor 2 of the present embodiment, the first magnetized boundary portions 16a and 16b, the magnet central axis 6C, and the central axis J are arranged side by side on the straight line L. Therefore, according to the motor 10 of the present embodiment having the rotor 2 employing the structure of the third rotor 2C, even if the magnet 6 rotates in an eccentric state, it is possible to reduce the deterioration of the rotation accuracy of the FG signal. it can.
Therefore, the motor 10 of the present embodiment can reduce the deterioration of the rotation accuracy of the FG signal without being affected by the eccentricity generated in the rotor. Therefore, the motor 10 of the present embodiment can output an FG signal with high rotation accuracy.

(Motor manufacturing method)
Subsequently, a method for manufacturing the motor 10 of the present embodiment will be described. In the present description, since the method of manufacturing the rotor 2 of the motor 10 is characterized, the method of manufacturing the rotor 2 will be mainly described below.

7A to 7C are views for explaining a method of manufacturing the rotor 2.
First, a shake detection step is performed. FIG. 7A is a diagram illustrating a shake detection step.
In the run-out detection step, as shown in FIG. 7A, a rotor component member 20 in which a hollow cylindrical magnet material 26 is attached to the inner peripheral side of a covered cylindrical rotor core 8 having a shaft 9 extending along the central axis J. Prepare The magnet material 26 is a material made of a magnetic material, and configures the magnet 6 by being magnetized. The magnet material 26 is attached to the inner peripheral side of the rotor core 8 via the adhesive 7.

  As described above, since the thickness of the adhesive 7 becomes non-uniform depending on the location due to a change in volume before and after curing, the magnet material 26 is displaced with respect to the rotor core 8. Specifically, in the rotor component member 20, the center axis J of the rotor core 8 and the center axis (magnet material center axis) 26C of the magnet material 26 are arranged at positions different from each other. The central axis 26C coincides with the magnet central axis 6C of the magnet 6.

Subsequently, in the rotor component 20, the direction of the run-out E with respect to the central axis J (the shaft 9) at the central axis 26C is determined. As a method of determining the direction of the run-out, for example, in a state where the roller is in contact with the inner peripheral surface of the magnet material 26, the roller is moved over the entire inner peripheral surface by rotating the rotor component member 20. Thus, the position of the center axis 26C of the magnet material 26 is obtained, and the deflection of the center axis 26C with respect to the center axis J is detected.
In this way, the run-out detection step of detecting run-out E in rotor component member 20 is completed.

  In the runout detection step, after detecting runout of the rotor constituent member 20, the rotor constituent member 20 is vacuum-fixed, for example, to a marking device that performs a marking process described below while maintaining the orientation of the rotor constituent member 20. The component 20 is delivered.

Subsequently, a marking step is performed. FIG. 7B is a diagram illustrating the marking step.
In the marking step, as shown in FIG. 7B, marking is performed on the outer peripheral surface 8a of the rotor core 8 based on the detection result of the above-described deflection detection step. Specifically, in the marking step, marking is performed on a position having a predetermined positional relationship with respect to a straight line L3 passing through the central axis 26C and the central axis J in the outer peripheral surface 8a.

  In the present embodiment, a location having a predetermined positional relationship with the straight line L3 on the outer peripheral surface 8a refers to a location overlapping the straight line L3. That is, the mark (marking portion) M marked in the marking step is aligned with the center axis 26C and the center axis J on a straight line.

  In the present embodiment, the mark M is provided in a range of ± 3 ° or less in the circumferential direction with respect to the straight line L3 as the position accuracy of the marking. For example, when the size of the rotor constituent member 20 (the rotor core 8) is φ20.7 mm, the width H of the mark M by the marking within the range of ± 3 ° or less in the circumferential direction is 1.08 mm or less.

Here, the method of performing the marking is not particularly limited. For example, the mark M may be formed on the outer peripheral surface 8a using a magic pen.
In the present embodiment, the mark M composed of a plurality of ink droplets is marked by using an inkjet method using an inkjet device. The ink jet device performs marking, for example, in a state where the rotor component member 20 is vacuum-fixed. Note that the ink jet device may determine whether or not the mark M is accurately marked after marking by an imaging device such as a CCD camera after marking.

Since the ink jet method is used in the marking step of the present embodiment, the mark M can be accurately marked with a desired width by discharging ink droplets on the outer peripheral surface 8a of the rotor core 8. Unlike the laser marking, the marking by the ink-jet method can make the mark M without damaging the surface of the rotor core 8.
Thus, the marking process on the rotor component 20 is completed.

Subsequently, a magnetizing step is performed. FIG. 7C is a diagram illustrating the magnetizing step.
In the magnetizing step, as shown in FIG. 7C, the magnet material 26 is magnetized based on the mark M in the marking step to obtain the magnet 6. Specifically, the magnet material 26 is magnetized from outside the rotor core 8 by inserting the rotor constituent member 20 into the magnetized yoke 40.

  As shown in FIG. 2, the magnet 6 has first magnetized boundary portions 16a and 16b in which the S pole 6s and the N pole 6n are arranged from the rear to the front in the rotation direction R. In the magnetization step, magnetization is performed based on the mark M in a state where the magnet material 26 and the magnetization yoke 40 are aligned so that the first magnetization boundary portions 16a and 16b are located on the straight line L3. .

According to the present embodiment, by aligning the magnet material 26 and the magnetized yoke 40 with the mark M positioned on the straight line L3 as a mark, the first magnetized boundary portions 16a and 16b are positioned on the straight line L3. Magnet 6 can be generated.
Thus, the magnetizing step of the magnet 6 is completed.

  In the present embodiment, the mark M is provided in a range of ± 3 ° or less in the circumferential direction with respect to the straight line L3 as described above. In the magnetizing step of the present embodiment, the magnetizing material 26 and the magnetizing yoke 40 are aligned based on the mark M to perform magnetizing. Can be suppressed to ± 8 ° or less.

  Since the center axis 26C coincides with the magnet center axis 6C of the magnet 6, the straight line L3 passing through the center axis 26C and the center axis J corresponds to the above-described straight line L passing through the magnet center axis 6C and the center axis J. . Therefore, according to the magnetizing step of the present embodiment, the above-described rotor 2 in which the first magnetized boundary portions 16a and 16b are located on the straight line L can be manufactured.

  In the marking process at the time of manufacturing the motor 10, the position where the mark M is provided is not limited to a position overlapping the straight line L3. In other words, when the mark M is provided, the position of the straight line L3 passing through the center axis 26C and the center axis J can be specified based on the mark M when the magnet 6 is magnetized to generate the magnet 6. It may be any place. If the position of the straight line L3 can be specified, the magnetization can be performed with the magnet material 26 and the magnetized yoke 40 aligned with each other so that the first magnetized boundary portions 16a and 16b are located on the straight line L3. . Further, the mark M may be composed of a plurality of parts. For example, the mark M may be formed by two marks separated from each other in the circumferential direction of the outer peripheral surface 8a. In this case, the mark M may be configured so that the center of the two marks in the circumferential direction is located on the straight line L3. The mark M has a predetermined positional relationship with the straight line L3, that is, the midpoint of the two marks is located on the straight line L3.

  Subsequently, the motor 10 shown in FIG. 1 is manufactured by assembling the stator 1, the rotor 2, the bearing 3, the circuit board 4, and the detecting element 5 with respect to the rotor 2 manufactured as described above. be able to.

FIG. 8 is a diagram showing the appearance of the motor of the present embodiment.
As shown in FIG. 8, the motor 10 of the present embodiment has a mark (marking portion) M provided on the outer peripheral surface 8a of the rotor core 8. This mark M is obtained by the above-described marking process. As described above, the central axis 26C coincides with the magnet central axis 6C. Therefore, the mark M is provided on the outer peripheral surface 8a so as to have a predetermined positional relationship with the straight line L passing through the magnet center axis 6C and the center axis J. Specifically, the mark M is provided on the outer peripheral surface 8a located on the straight line L. In the motor 10 of the present embodiment, the mark M, the first magnetized boundary portions 16a and 16b, the magnet center axis 6C, and the center axis J are located on the straight line L.

  As described above, according to the motor 10 of the present embodiment, by magnetizing the magnet 6 based on the mark M, the first magnetized boundary portions 16a and 16b, the magnet center axis 6C, and the center axis J are aligned. The rotor 2 is arranged on the straight line L. Therefore, according to the motor 10 including the rotor 2, even when the rotor is eccentric, the deterioration of the rotation accuracy of the FG signal can be reduced without being affected by the eccentricity.

  Subsequently, an outline of a vehicle headlamp equipped with the motor 10 of the present embodiment will be described. FIG. 9 is a horizontal sectional view of the vehicle headlamp. The vehicle headlamp 100 shown in FIG. 9 is a left headlamp mounted on the left side of the front end of the vehicle, and has the same structure as the headlamp mounted on the right side except that it is bilaterally symmetric. Therefore, hereinafter, the left vehicle headlamp 100 will be described in detail, and the description of the right vehicle headlamp will be omitted.

  As shown in FIG. 9, the vehicle headlamp 100 includes a lamp body 112 having a concave portion that opens forward. The lamp body 112 has a transparent front cover 114 whose front opening is covered by a front cover 114 to form a lamp chamber 116. The lamp room 116 functions as a space in which the lamp unit 118 is housed.

  The lamp unit 118 is a unit that employs a blade scan type ADB technology, and is configured to emit a so-called variable high beam. The lamp unit 118 includes an optical unit 120 and a projection lens 122. The optical unit 120 includes a rotating reflector 124 and a light source 126. As the projection lens 122, for example, a convex lens is used. The shape of the convex lens may be appropriately selected according to the light distribution characteristics such as a required light distribution pattern and illuminance distribution, and an aspheric lens or a free-form surface lens is used. An extension reflector 123 is provided around the projection lens 122.

  The rotating reflector 124 reflects the light emitted from the light source 126 while rotating in one direction around the rotation axis O1 by the motor 10 as a driving source, and forms a light distribution pattern by scanning the reflected light. It is configured as follows. In addition, the rotary reflector 124 includes an annular reflection region 124a configured to reflect the light emitted from the light source 126 while rotating, and to form a desired light distribution pattern. The control circuit 148 controls the light distribution pattern using the FG signal output from the motor 10. Since the motor 10 of the present embodiment outputs an FG signal with high rotation accuracy, the control circuit 148 can control the light distribution pattern with high accuracy.

  The light source 126 is preferably capable of controlling turning on and off in a short time, and for example, a semiconductor light emitting element such as an LED, an LD, and an EL element is suitable.

  The motor 10 is mounted on a board 132. The substrate 132 is mounted and fixed on the mounting surface 134a of the heat sink 134. The mounting surface 134a is configured such that the rotation axis O1 of the rotary reflector 124 is inclined with respect to the optical axis Ax or the forward direction of the vehicle when the substrate 132 is mounted.

  The light source 126 is mounted on the substrate 136. A lens 138 as a primary optical system is provided in the light emitting direction of the light source 126 and between the rotating reflector 124 and the light emitting direction. The lens 138 condenses the light emitted from the light source 126 so that the light emitted from the light source 126 is directed to the reflection area 124a of the rotary reflector 124. The substrate 136 is mounted on the heat sink 140. The heat sink 134 and the heat sink 140 are fixed to a metal plate-shaped support member 142. The lamp unit 118 is supported by a means using an aiming screw 144 and a nut 146 via a support member 142 so as to be tiltable with respect to the lamp body 112.

  The control circuit 148 is connected to the light source 126 and the motor 10 via each substrate, and transmits a signal for controlling the light source 126 and the motor 10 and receives an FG signal output from the motor 10.

  As mentioned above, although one Embodiment of this invention was described, each structure in embodiment, their combination, etc. are an example, and addition, abbreviation, substitution, and other addition of a structure do not deviate from the meaning of this invention. Changes are possible. The present invention is not limited by the embodiments.

  2, 12 rotor, 4b output section, 5 detection element, 6 magnet, 6n N pole (second pole), 6s S pole (first pole), 6C magnet center axis, 7 adhesive , 8 ... rotor core, 9 ... shaft, 10 ... motor, 15 ... magnetization boundary, 16a, 16b ... first magnetization boundary, 17a, 17b ... second magnetization boundary, 26C, J ... center axis, L ... Line, R ... Rotation direction.

Claims (5)

A rotor having a covered cylindrical rotor core having a shaft extending along a central axis, and a hollow cylindrical magnet provided on the inner peripheral side of the rotor core;
A detection element for detecting a magnetic flux density of the magnet;
A signal output unit that outputs a signal related to the rotation speed of the rotor based on the magnetic flux density,
The magnet has a first pole and a second pole alternately arranged along a circumferential direction, and a first magnetized boundary portion in which the first pole and the second pole are arranged in a direction opposite to a rotation direction and the rotation. A second magnetized boundary in which the second pole and the first pole are arranged in a direction opposite to a direction,
When viewed in a plan view from a direction along the central axis, the first magnetized boundary portion is located on a straight line passing through the magnet central axis passing through the center of the magnet and the central axis,
motor. The signal output unit outputs the signal according to a timing at which the magnetic flux density changes from a first detection value to a second detection value,
The motor according to claim 1. Further comprising a substrate arranged to face the rotor,
The detection element is provided on a surface of the substrate facing the rotor,
The motor according to claim 1. The motor according to claim 3, wherein the signal output unit is provided on the substrate. The magnet is attached to the rotor core with an adhesive,
The motor according to claim 1.

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