JP2020088976A - motor - Google Patents

Abstract

To provide a motor which can be easily formed and has high sensitivity.SOLUTION: A motor 1 includes: a magnet holder 15 that has a first magnet 161 whose N pole and S pole are magnetized one by one and a second magnet 162 whose N pole and S pole are magnetized in plural, and being rotatable along with both magnets 16 of the first magnet 161 and the second magnet 162; and a substrate 60 on which a first magnetism sensitive element 171 provided opposed to the first magnet 161 in a rotation axis direction L of the magnet holder 15 and a second magnetic sensitive element 172 provided oppositely to the second magnet 162 in a rotation axis direction L are implemented. The second magnetic sensitive element 172 protrudes toward the magnet 16 side rather than the first magnetic sensitive element 171.SELECTED DRAWING: Figure 12

Description

The present invention relates to a motor.

Conventionally, various motors have been used. Among them, for example, in Patent Document 1, a first magnet in which an N pole and a S pole are magnetized one by one, and a magnet which is provided around the first magnet and has a large number of magnetizations (N pole and S A second magnet having a plurality of poles) and a magnet holder rotatable together with both the first magnet and the second magnet, and further having a first magnetism facing the first magnet. A motor is disclosed that includes a substrate unit having an element and a second magnetic sensing element that faces the second magnet.

2018-42332 publication

However, since the motor of Patent Document 1 is provided with the first magnetic sensing element on the substrate and the second magnetic sensing element on the substrate holder which is a different member different from the substrate, the motor includes the substrate and the substrate holder. Assembly of the board unit may be troublesome. Further, since the second magnet has a large number of magnetizations and the magnetic flux does not reach far, the magnetic detection by the second magnetic sensing element is highly sensitive when the distance between the second magnetic sensing element and the second magnet is wide. It may be difficult to detect magnetism.

Therefore, an object of the present invention is to provide a motor that can be easily formed and has high sensitivity.

The motor of the present invention has a first magnet magnetized with one N pole and one S pole, and a second magnet magnetized with a plurality of N and S poles. And a magnet holder that is rotatable with both of the second magnets, a first magnetic sensing element that is provided to face the first magnet in the rotation axis direction of the magnet holder, and the first magnetism element in the rotation axis direction. A substrate on which a second magnetism sensing element provided facing the two magnets is mounted, and the second magnetism sensing element projects toward the magnet side more than the first magnetism sensing element. Is characterized by.

According to this aspect, the first magnetic sensitive element and the second magnetic sensitive element are both mounted on the substrate, so that the substrate unit can be easily assembled. Further, since the second magnetic sensitive element projects toward the magnet side more than the first magnetic sensitive element, the distance between the second magnetic sensitive element and the second magnet can be easily narrowed. Therefore, a motor that can be easily formed and has high magnetic detection sensitivity can be provided.

The motor of the present invention includes a substrate holder that covers the substrate on the magnet side in the rotation axis direction, and the substrate is a signal ground connected to the ground terminals of the first magnetic sensing element and the second magnetic sensing element. The substrate holder has an opening at the position of the second magnetic sensing element viewed from the rotation axis direction, and the opening has a thinner shield in the rotation axis direction than the substrate holder. It is preferable that the substrate holder and the shield member are covered with a member, and that both the substrate holder and the shield member are formed of a conductive member and are connected to the signal ground. By shielding the second magnetic sensitive element with a thin shield member, noise (frame ground noise, power source noise, etc.) from the magnet side is applied to the second magnetic sensitive element while keeping the distance between the second magnetic sensitive element and the second magnet narrow. This is because it is possible to suppress the influence of () entering the magnetic detection result.

In the motor of the present invention, it is preferable that a position of the first magnetic sensing element facing the first magnet is covered with the substrate holder. This is because the intrusion of noise from the magnet side into the first magnetic sensing element and the influence on the magnetic detection result can be suppressed with a simple configuration.

In the motor of the present invention, it is preferable that the second magneto-sensitive element does not protrude beyond the substrate holder toward the second magnet. This is because it is possible to prevent the second magnetic sensing element from contacting another member or the like. Further, when the shield member is attached to the substrate holder, the shield member can be easily attached without being deformed.

In the motor of the present invention, the distance between the second magnetic sensing element and the second magnet is preferably narrower than the distance between the first magnetic sensing element and the first magnet. Since the second magnet has a larger number of magnetizations than the first magnet and the magnetic flux does not reach far from the first magnet, the distance between the second magnetic sensing element and the second magnet is set to the first magnetic sensing element and the first magnet. This is because it is possible to detect the magnetism with high sensitivity in both the first magnetic sensing element and the second magnetic sensing element by making the distance narrower than the distance between and.

In the motor of the present invention, the second magnetic sensing element has a magnetic sensing film, and the position of the magnetic sensing film on the second magnetic sensing element in the rotation axis direction is the second sensing element in the rotation axis direction. It is preferable to be closer to the second magnet than the center of the magnetic element. This is because the position of the magnetic sensitive film can be brought close to the magnet, and the magnetic detection can be performed with high sensitivity.

In the motor of the present invention, the second magnet is arranged around the first magnet, and a shield wall is provided over the entire circumference between the first magnet and the second magnet. It is preferable that the shield wall does not protrude beyond the second magnet toward the substrate side. By providing a shield wall that does not exceed the second magnet between the first magnet and the second magnet, while suppressing the influence of the magnetic flux from the first magnet to the second magnet, the shield wall exceeds the second magnet. It is possible to suppress the magnetic flux of the second magnet from going to the shield wall and weakening the magnetic flux to the second magneto-sensitive element, as compared with the case where it is present.

In the motor of the present invention, it is preferable that the shield wall projects toward the substrate beyond the first magnet. This is because the shield wall protruding beyond the first magnet toward the substrate can suppress the influence of the magnetic flux traveling from the first magnet to the second magnet.

In the motor of the present invention, it is preferable that the second magnet is magnetized while being fixed to the magnet holder. This is because center deviation of the second magnet with respect to the rotation axis can be suppressed.

The present invention can provide a motor that can be easily formed and has high magnetic detection sensitivity.

It is an appearance perspective view showing an end side by the side of the encoder of a motor to which the present invention is applied. It is an exploded perspective view which looked at an encoder and a bearing holder from the counter output side. It is an exploded perspective view of the encoder and the bearing holder as seen from the output side. It is sectional drawing (AA sectional drawing of FIG. 1) of an encoder and a bearing holder. It is sectional drawing (BB sectional drawing of FIG. 1) of an encoder and a bearing holder. FIG. 4 is an exploded perspective view of the board unit, the magnet, and the magnet holder as viewed from the opposite output side. It is an exploded perspective view of the substrate unit, the magnet, and the magnet holder as seen from the output side. FIG. 6 is a plan view showing a layout of a rotary magnet and a magnetic sensing element sensor section of an encoder of a motor to which the present invention is applied. It is a perspective view showing a layout of a rotary magnet and a magnetic sensitive element sensor section of an encoder of a motor to which the present invention is applied. It is a phase diagram for demonstrating the detection principle in the encoder to which this invention is applied. It is a figure for demonstrating the detection principle in the encoder to which this invention is applied. It is a schematic diagram showing a layout of a rotary magnet and a magnetic sensing element sensor section of an encoder of a motor to which the present invention is applied.

Embodiments of a motor to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is an external perspective view showing an end portion of a motor 1 to which the present invention is applied on the encoder 10 side. 2 and 3 are exploded perspective views of the encoder 10 and the bearing holder 42, FIG. 2 is an exploded perspective view seen from the opposite output side, and FIG. 3 is an exploded perspective view seen from the output side. 4 and 5 are sectional views of the encoder 10 and the bearing holder 42, FIG. 4 is a sectional view taken along the line AA of FIG. 1, and FIG. 5 is a sectional view taken along the line BB of FIG.

(overall structure)
The motor 1 includes a motor body 3 having a rotating shaft 2 (see FIGS. 4 and 5), and an encoder 10 for detecting the rotation of the rotating shaft 2. The motor body 3 includes a motor case 4 that houses a rotor and a stator (not shown). The rotor rotates together with the rotary shaft 2. One end of the rotary shaft 2 serves as an output shaft (not shown) protruding from the motor case 4 to the outside. In the present specification, the central axis (rotation axis) of the rotation shaft 2 is indicated by the symbol L. The rotation axis L corresponds to the rotation axis of the magnet holder 15. The direction in which the output shaft projects from the motor case 4 is the output side L1, and the side opposite to the output side is the counter output side L2. The encoder 10 is fixed to the end of the motor body 3 on the opposite output side L2.

(Axis of rotation)
As shown in FIGS. 4 and 5, the rotary shaft 2 includes a motor-side rotary shaft 21 and an encoder-side rotary shaft 22 fixed to an end of the motor-side rotary shaft 21 on the opposite output side L2. The motor side rotary shaft 21 and the encoder side rotary shaft 22 rotate integrally. In this embodiment, the motor-side rotating shaft 21 is made of a magnetic material and the encoder-side rotating shaft 22 is made of a non-magnetic material. If the encoder-side rotary shaft 22 is made of a non-magnetic material, magnetic noise that enters from the motor body 3 side to the encoder 10 side via the encoder-side rotary shaft 22 can be reduced. The encoder side rotation shaft 22 may be a magnetic material. In this case, the encoder side rotary shaft 22 and the motor side rotary shaft 21 may be integrated. That is, the rotating shaft 2 may be formed of one member.

(Motor case)
As shown in FIG. 1, the motor case 4 includes a tubular case 41 extending in the direction of the rotation axis L, and a bearing holder 42 fixed to an end of the tubular case 41 on the opposite output side L2. The cylindrical case 41 and the bearing holder 42 are substantially rectangular when viewed in the rotation axis L direction. As shown in FIGS. 2 to 5, the bearing 43 is held on the inner peripheral side of the bearing holder 42. The bearing 43 rotatably supports the end portion on the output side L1 of the encoder-side rotation shaft 22. As shown in FIG. 2, a circular recess 44 that is recessed toward the output side L1 is formed on the surface of the bearing holder 42 opposite to the output side L2, and a flange 45 is formed on the outer peripheral side of the circular recess 44. An annular wall 46 is formed on the inner peripheral edge of the flange 45 along the edge of the circular recess 44 so as to project to the opposite output side L2.

An annular plate 47 is attached to the bottom of the circular recess 44 so as to press the outer peripheral portion of the bearing 43 from the opposite output side L2. The encoder-side rotation shaft 22 projects to the counter output side L2 through a through hole 48 provided at the center of the plate 47. The plate 47 is fixed to the bottom of the circular recess 44 by three screws. Notches 49 are formed on the outer peripheral edge of the plate 47 at three positions at equal angular intervals. A leg portion 143 of the encoder holder 14, which will be described later, is arranged in the cutout 49.

(Encoder)
As shown in FIGS. 2 to 5, the encoder 10 includes an outer case 11 fixed to the bearing holder 42, an encoder cover 12 arranged inside the outer case 11, and a substrate arranged inside the encoder cover 12. The unit 13 includes an encoder holder 14 that supports the substrate unit 13, a magnet holder 15 arranged on the inner peripheral side of the encoder holder 14, and a magnet 16 (rotating magnet) held by the magnet holder 15. The magnet holder 15 is fixed to the tip of the encoder-side rotation shaft 22 on the opposite output side L2. Therefore, the magnet 16 rotates integrally with the encoder side rotation shaft 22. The board unit 13 includes a magnetic sensitive element 17 (magnetic sensitive element sensor portion) that faces the magnet 16. In this embodiment, an MR element is used as the magnetic sensing element 17.

(Outer case)
As shown in FIGS. 2 and 3, the outer case 11 includes an end plate portion 111 having a substantially rectangular shape when viewed in the rotation axis L direction, and a side plate portion 112 that rises from the outer peripheral edge of the end plate portion 111 to the output side L1. Prepare The side plate portion 112 is formed with a notch 113 for passing a wiring connected to the board unit 13. In the outer case 11 and the bearing holder 42, a seal member 114 is interposed between the end surface of the output side L1 of the side plate portion 112 and the flange 45, and fixing members such as screws (not shown) are tightened at four corners. Fixed by. In this embodiment, the outer case 11 and the motor case 4 are made of a non-magnetic material such as aluminum. In this embodiment, the outer case 11 is a separate member from the encoder cover 12 described below, but the outer case 11 may be integrally formed of the same material as the encoder cover 12.

(Encoder cover)
As shown in FIGS. 2 and 3, the encoder cover 12 includes a circular end plate portion 121 when viewed in the rotation axis L direction, and a tubular portion 122 that rises from the outer peripheral edge of the end plate portion 121 to the output side L1. Prepare The tubular portion 122 is formed with a notch 123 at a position that radially overlaps with the notch 113 of the outer case 11 and through which a wiring connected to the board unit 13 is inserted. As shown in FIGS. 4 and 5, the encoder cover 12 is configured so that the edge of the tubular portion 122 is fitted to the inner peripheral side of the annular wall 46 formed along the edge of the circular recess 44 of the bearing holder 42. It is assembled to the bearing holder 42. The end face of the tubular portion 122 on the output side L1 contacts the plate 47 arranged at the bottom of the circular recess 44, except for the portion where the notch 123 is formed. Here, although the annular wall 46 is partially cut out in the circumferential direction, the cutout portion of the annular wall 46 is at an angular position different from the notch 49 formed on the outer peripheral edge of the plate 47. .. Therefore, the gap between the encoder cover 12 and the bearing holder 42 is closed except for the notch 123.

The encoder cover 12 is made of a conductive magnetic material. For example, the encoder cover 12 is made of iron, permalloy or the like. More specifically, the encoder cover 12 is formed by pressing a magnetic metal plate such as SPCC or SPCE. Thus, by covering the board unit 13 holding the magnetic sensitive element 17 with the encoder cover 12 formed of a magnetic material, the magnetic sensitive element 17 and the encoder circuit can be shielded from magnetic noise such as a disturbance magnetic field. Further, the encoder cover 12 is attached so that there is almost no gap between the encoder cover 12 and the bearing holder 42. Therefore, it is possible to prevent electromagnetic wave noise from entering the board unit 13 side through the gap with the bearing holder 42.

As another means, the encoder cover 12 may be attached to the substrate holder 50 of the substrate unit 13 so that there is no space between the encoder cover 12 and the substrate holder 50 to suppress the intrusion of electromagnetic noise. Specifically, the tubular portion 122 of the encoder cover 12 extends to the outer peripheral side of the substrate unit 13, and the tip of the tubular portion 122 is projected from the outer peripheral end of the substrate holder 50 to the output side L1. That is, the tubular portion 122 extends to the position on the output side L1 from the magnetic sensitive element 17 mounted on the substrate 60, and the tubular portion 122 surrounds the outer peripheral side of the magnetic sensitive element 17 so that electromagnetic wave noise can enter. Can be suppressed. In that case, it is desirable to electrically connect to the signal ground of the encoder circuit on the substrate 60 via the conductive fixing member 70 and the substrate holder 50.

The encoder cover 12 is attached so as to be in contact with the bearing holder 42, and thus is electrically connected to the frame ground of the motor body 3. That is, the bearing holder 42 constitutes a part of the motor case 4 made of a conductive metal such as aluminum. Therefore, the encoder cover 12 is electrically connected to the frame ground of the motor body 3 by fitting the tubular portion 122 of the encoder cover 12 inside the annular wall 46 provided on the bearing holder 42. In this way, by connecting the encoder 10 to the frame ground potential, the effect of shielding electromagnetic noise can be enhanced. Even if the tubular portion 122 of the encoder cover 12 is not fitted inside the annular wall 46, if the end face of the tubular portion 122 of the encoder cover 12 is fixed so as to contact the bottom of the circular recess 44, The encoder cover 12 and the motor body 3 can be connected to the frame ground potential.
Alternatively, the encoder cover 12 may be fixed to the substrate unit 13 and electrically connected to the signal ground of the encoder circuit on the substrate 60 via the conductive fixing member 70 and the substrate holder 50.

(Encoder holder)
As shown in FIGS. 2 and 3, the encoder holder 14 includes a body 142 having a circular magnet placement hole 141, and a leg 143 projecting from the end of the body 142 on the output side L1 to the outer peripheral side. Prepare As shown in FIG. 3, the end surface on the output side L1 of the leg portion 143 projects to the output side L1 more than the end surface on the output side L1 of the body portion 142. The leg portions 143 are formed at three positions at equal angular intervals in the circumferential direction. The encoder holder 14 is positioned so that the rotation axis L of the encoder-side rotation shaft 22 rotatably held in the center of the bearing holder 42 and the magnet arrangement hole 141 are arranged coaxially with each other, and the encoder holder 14 has the above-mentioned plate 47. The leg portion 143 is positioned so as to be placed in the notch 49 formed in the outer peripheral edge. As shown in FIG. 5, the encoder holder 14 contacts the bearing holder 42 via the leg portion 143. The encoder holder 14 is fixed to the bearing holder 42 by fixing the leg portion 143 to the bottom surface of the circular recess 44 with a fixing screw (not shown).

In the encoder holder 14, fixing holes 144 for fixing the board unit 13 are formed at three positions on the end surface of the body 142 opposite to the output side L2. The board unit 13 is positioned so as to come into contact with the end surface of the body portion 142 on the opposite output side L2, and is fixed to the encoder holder 14 via a fixing member such as a screw (not shown).

(magnet)
6 and 7 are exploded perspective views of the substrate unit 13, the magnet 16 and the magnet holder 15, FIG. 6 is a view seen from the opposite output side L2, and FIG. 7 is a view seen from the output side. As shown in FIGS. 6 and 7, the magnet holder 15 includes a substantially disk-shaped magnet holding portion 151 and a tubular fixing portion 152 protruding from the center of the magnet holding portion 151 to the output side L1. The tip of the encoder-side rotary shaft 22 is fixed to the fixing portion 152 by press fitting or an adhesive. Alternatively, it is fixed by a set screw from a direction perpendicular to the output side L1. A shield wall 153 is provided between the magnet holding portion 151 and the fixed portion 152. The magnet 16 includes a circular first magnet 161 that fits in a recess formed in the center of the magnet holding portion 151 and an annular second magnet 162 that fits in a step formed on the outer peripheral edge of the first magnet. Equipped with. The first magnet 161 is magnetized such that one north pole and one south pole are arranged in the circumferential direction. On the other hand, the second magnet 162 has a plurality of N poles and S poles alternately magnetized in the circumferential direction. The details of the configuration of the rotating body 18 including the encoder holder 14, the magnet 16, and the magnet holder 15 will be described later.

As shown in FIGS. 4 and 5, when the encoder holder 14 is fixed to the bearing holder 42, the tip of the encoder-side rotary shaft 22 is arranged in the center of the magnet arrangement hole 141 of the encoder holder 14. Therefore, the magnet holder 15 fixed to the tip of the encoder side rotation shaft 22 is arranged in the center of the magnet arrangement hole 141. The first magnet 161 and the second magnet 162 are arranged in the magnet arrangement hole 141 so as to face the opposite output side L2 and are arranged coaxially with the rotation axis L of the encoder side rotation shaft 22 as the center.

(Board unit)
As shown in FIGS. 6 and 7, the substrate unit 13 includes a substrate holder 50, a substrate 60 attached to the substrate holder 50, a magnetic sensing element 17 mounted on the substrate 60, and the substrate 60 fixed to the substrate holder 50. And a shield member 80 attached to the substrate holder 50 from the output side L1. The substrate 60 has a substantially circular shape, and is provided with notches 61 that are linearly cut at two locations on the outer peripheral edge. Further, the substrate 60 is formed with two fixing holes 62 for fixing the substrate holder 50. The two fixing holes 62 are arranged on opposite sides of the center of the substrate holder 50. Further, one of the two fixing holes 62 is a ground through hole 621 electrically connected to the signal ground 5 (see FIG. 12) of the encoder circuit mounted on the substrate 60. Either of the two fixing holes 62 may be the ground through hole 621. Further, the fixing holes 62 may be provided at three or more places, and the substrate 60 and the substrate holder 50 may be fixed at the three places.

The substrate holder 50 includes an end plate portion 53 that faces the substrate 60, and a side plate portion 54 that rises from the outer peripheral edge of the end plate portion 53 to the counter output side L2. The substrate holder 50 has a shape in which the end plate portion 53 is linearly cut at a portion overlapping the cutout 61 of the substrate 60 in the rotation axis L direction, and the side plate portion 54 extends linearly. Boss portions 51 corresponding to the fixing holes 62 of the substrate 60 are formed at two positions on the end plate portion 53. The substrate 60 is fixed to the substrate holder 50 by inserting the fixing member 70 into the fixing hole 62 and the boss portion 51. The fixing member 70 is a spring pin. By using the spring pin as the fixing member 70, rattling of the substrate 60 with respect to the substrate holder 50 is prevented. The fixing member 70 is made of a conductive metal such as SUS, and the substrate holder 50 is made of a conductive metal such as aluminum. Therefore, when the substrate 60 is attached to the substrate holder 50 via the fixing member 70, the substrate holder 50 is electrically connected to the signal ground 5 of the encoder circuit mounted on the substrate 60 via the fixing member 70 and the ground through hole 621. Connected to.

The substrate holder 50 is provided with boss portions 52 through which fixing screws (not shown) are inserted at three positions corresponding to the fixing holes 144 of the encoder holder 14. The boss portion 52 is connected to the side plate portion 54. In this embodiment, the tip surface of the boss portion 52 is a contact surface that contacts the substrate 60. Further, the board 60 is formed with fixing holes 63 for passing fixing screws through three places corresponding to the boss portion 52 and the fixing hole 144. Although not shown in FIG. 2, two positioning pins for positioning the board unit 13 are provided so as to project from the end surface of the body portion 142 on the opposite output side L2.

The substrate unit 13 is fixed to the encoder holder 14 by passing three fixing screws through the fixing hole 63 of the substrate 60 and the boss portion 52 of the substrate holder 50 and screwing the tip of the fixing screw into the fixing hole 144. Further, since the leg portion 143 of the encoder holder 14 is fixed by contacting the bearing holder 42, the substrate unit 13 is fixed to the bearing holder 42 via the encoder holder 14. In this embodiment, the encoder holder 14 is made of an insulating material such as resin. Therefore, when the substrate unit 13 is fixed to the bearing holder 42 via the encoder holder 14, the substrate holder 50 is insulated from the bearing holder 42. However, a wiring pattern for the frame ground is prepared on the substrate 60, and in a state where a metal member (not shown) is connected to the wiring pattern for the frame ground, one of the legs 143 of the encoder holder 14 and a screw are used. They are fastened together and electrically connected to the bearing holder 42. Therefore, since the wiring pattern for the frame ground is wired so as to be electrically connected to the shield of the encoder cable connected to the board unit 13, noise applied to the cable is suppressed.

The substrate 60 includes a non-output side substrate surface 60a facing the non-output side L2 and an output side substrate surface 60b facing the output side L1. As shown in FIG. 6, on the counter-output side substrate surface 60a, a circuit element (not shown) forming an encoder circuit, a connector 65 for connecting an encoder cable, and the like are mounted. As shown in FIG. 7, the magnetic sensing element 17 includes a first magnetic sensing element 171 and a second magnetic sensing element 172 arranged at the center of the output side substrate surface 60b. The first magnetic sensing element 171 and the second magnetic sensing element 172 respectively include ground terminals 6 and 7 (see FIG. 12) connected to the signal ground 5 of the encoder circuit formed on the substrate 60. Two Hall elements 175 are mounted near the first magnetic sensing element 171 on the output side substrate surface 60b. The two Hall elements 175 are arranged at angular positions separated by 90 degrees. The first magnetic sensitive element 171, the second magnetic sensitive element 172, and the two Hall elements 175 are all mounted on the substrate 60.

In the substrate holder 50, a substantially rectangular through hole (opening 58) is formed on the output side L1 surface of the end plate portion 53. When the substrate 60 is fixed to the substrate holder 50, the second magnetic sensing element 172 is arranged in the opening 58.

When the board unit 13 is fixed to the encoder holder 14, the first magnetic sensing element 171 and the first magnet 161 face each other (see FIGS. 4 and 5). The second magnetic sensing element 172 and the second magnet 162 arranged in the opening 58 of the substrate holder 50 face each other. The encoder 10 has a predetermined gap between the surface of the output side L1 of the first magnetic sensing element 171 and the first magnet 161, and between the surface of the output side L1 of the second magnetic sensing element 172 and the second magnet 162. Is formed.

The first magnetic sensitive element 171 and the two Hall elements 175 and the first magnet 161 arranged in the vicinity thereof determine the output cycle of the first magnetic sensitive element 171 obtained by one rotation by the two Hall elements 175. By doing so, it functions as an absolute encoder. On the other hand, the second magnetic sensing element 172 and the second magnet 162 function as an incremental encoder because the output of a plurality of cycles is obtained by one rotation. The encoder 10 can perform high-resolution and highly-accurate position detection by processing the outputs of these two sets of encoders.

(Shield member)
The shield member 80 is attached to the shield member attachment position 57 of the substrate holder 50 from the output side L1. The shield member 80 of this embodiment is a flexible sheet material and has a size that completely closes the opening 58. Although the shield member attachment position 57 of the present embodiment is not provided, a step for attaching the shield member 80 may be provided at the shield member attachment position 57. The shield member 80 contacts the shield mounting surface 59 facing the output side L1. Similar to the substrate holder 50, the shield member 80 is made of a conductive nonmagnetic metal such as aluminum. The shield member 80 is bonded to the shield mounting surface 59 via a conductive adhesive. Therefore, the shield member 80 is electrically connected to the signal ground 5 of the encoder circuit mounted on the substrate 60 via the substrate holder 50.

The shield member 80 is attached to the substrate holder 50 so as to cover the second magnetic sensing element 172 arranged in the opening 58. By attaching the shield member 80 to the substrate holder 50, the first magnetic sensitive element 171 and the second magnetic sensitive element 172 are shielded from the motor body 3 by the members having the signal ground potential (the substrate holder 50 and the shield member 80). .. Therefore, it is possible to effectively shield frame ground noise and power source noise that come around from the gap between the first magnet 161 and the second magnet 162. The first magnetic sensitive element 171 and the second magnetic sensitive element 172 face the first magnet 161 and the second magnet 162 via the shield member 80, but the shield member 80 and the substrate holder 50 are made of non-magnetic metal. Therefore, it is possible to prevent electromagnetic wave noise from being impaired and to prevent the function of the magnetic encoder from being impaired.

(Outline of layout of magnets and magnetic sensitive elements)
FIG. 8 is an explanatory view showing a layout of the magnet 16 (first magnet 161 and second magnet 162) and the magnetic sensitive element 17 (first magnetic sensitive element 171 and second magnetic sensitive element 172) in the encoder 10 of the present embodiment. FIG. 6 is a plan view showing a planar layout of magnets 16 and the like. 9 to 11 are explanatory diagrams showing the principle of the encoder 10 of the present embodiment. FIG. 9 is an explanatory diagram of a signal processing system for the magnetic sensitive element 17, and FIG. 10 shows signals output from the magnetic sensitive element 17. FIG. 11 is an explanatory diagram showing the relationship between such a signal and the angular position θ (electrical angle) of the rotating body 18 (the magnet holder 15 and the magnet 16). 8 and 9, the configurations of the magnet 16 and the magnetic sensitive element 17 are schematically shown, and the magnetic poles of the second magnet 162 are schematically shown with the number thereof reduced. Further, the positional relationship between the magnetoresistive pattern in the second magnetic sensing element 172 and the magnetic pole of the second magnet 162 is also schematically shown by shifting their positions, and the magnetic resistance pattern of the second magnetic sensing element 172 is It is formed in an extremely narrow range in the circumferential direction.

As shown in FIGS. 8 and 9, in the encoder 10 of the present embodiment, a rotating surface is provided with a magnetized surface 221 on the side of the rotating body 18 in which N poles and S poles are magnetized one by one in the circumferential direction. A first magnet 161 directed to the output side L1 in the direction L, and an annular magnetized structure in which a plurality of N poles and S poles are alternately magnetized in the circumferential direction at positions separated from the first magnet 161 on the outer side in the radial direction. The second magnet 162 that holds the magnetic surface 231 toward the output side L1 in the rotation axis direction L is held. The first magnet 161 and the second magnet 162 rotate together with the rotating body 18 around the rotation axis. 8 and 9, the second magnet 162 of the present embodiment has a pair of N and S poles, which form a pair of inside and outside, in the circumferential direction. It is provided as a pair.

In the present embodiment, the first magnet 161 is a disk-shaped permanent magnet. The second magnet 162 has a cylindrical shape and is arranged at a position spaced apart from the first magnet 161 on the outer side in the radial direction. The first magnet 161 and the second magnet 162 are bond magnets or the like. In this embodiment, for example, a ferrite sintered magnet is used. In the present embodiment, on the magnetized surface 231 of the second magnet 162, a plurality of tracks 310 in which N-poles and S-poles are alternately magnetized to have multiple poles in the circumferential direction are arranged in parallel in the radial direction. In this embodiment, two rows of tracks 310 are formed. The positions of the N pole and the S pole are displaced in the circumferential direction between the two tracks 310, and in the present embodiment, the N pole and the S pole are displaced by one pole in the circumferential direction between the two tracks 310.

The substrate unit 13 rotates relative to the magnetized surface 221 of the first magnet 161 and the magnetized surface 231 of the second magnet 162, and the first magnetic sensitive element 171 facing the magnetized surface 221 of the first magnet 161 on the output side L1 in the rotation axis direction L. The second magnetic sensing element 172 facing the output side L1 in the axial direction L is provided. In the present embodiment, both the first magnetic sensitive element 171 and the second magnetic sensitive element 172 are held on the output side substrate surface 60b of the output side L1 in the rotation axis direction L of the substrate 60, as shown in FIG. Has been done.

Further, on the substrate 60, the first hall element 175a is located at a position facing the first magnet 161, and the second hall element 175a is located at a position deviated from the first hall element 175a by 90° in mechanical angle in the circumferential direction. 175b are provided. In the present embodiment, both the first Hall element 175a and the second Hall element 175b are held on the output side substrate surface 60b of the substrate 60 and face the first magnet 161 on the output side L1 in the rotation axis direction L. ing.

As shown in FIGS. 8 and 9, the first magnetic sensing element 171 has a phase A (SIN) magnetic resistance pattern and a phase B (COS) having a phase difference of 90° with respect to the phase of the first magnet 161. ) Magnetic reluctance pattern of 1). In the first magneto-sensitive element 171, the A-phase magnetic resistance pattern includes a +a-phase (SIN+) magnetic-resistance pattern 243 and a -a phase (SIN-) that detect movement of the rotating body 18 with a phase difference of 180°. The magnetoresistive pattern 241 is provided, and the B-phase magnetoresistive pattern includes a +b-phase (COS+) magnetic-resistive pattern 244 and a −b-phase (COS−) that detect movement of the rotating body 18 with a phase difference of 180°. The magnetoresistive pattern 242 is provided.

Here, the +a phase magnetic resistance pattern 243 and the −a phase magnetic resistance pattern 241 form a bridge circuit, one end of which is connected to the power supply terminal (Vcc) and the other end of which is connected to the ground terminal (GND). It is connected. Further, a terminal (+a) for outputting the +a phase is provided at the center point of the +a phase magnetic resistance pattern 243, and a −a phase is output at the center point of the −a phase magnetic resistance pattern 241. The terminal (-a) is provided. Further, the +b-phase magnetic resistance pattern 244 and the −b-phase magnetic resistance pattern 242 also form a bridge circuit similarly to the +a-phase magnetic resistance pattern 244 and the −a-phase magnetic resistance pattern 241, and one end thereof is It is connected to the power supply terminal (Vcc) and the other end is connected to the ground terminal (GND). Further, a terminal (+b) for outputting the +b phase is provided at the center point of the +b phase magnetic resistance pattern 244, and a −b phase is output at the center point of the −b phase magnetic resistance pattern 242. The terminal (-b) is provided.

The second magnetic sensing element 172 includes an A-phase (SIN) magnetic resistance pattern and a B-phase (COS) magnetic resistance pattern having a phase difference of 90° with respect to the phase of the second magnet 162. Two magnetoresistive elements. In the second magneto-sensitive element 172, the A-phase magnetic resistance pattern includes a +a-phase (SIN+) magnetic-resistance pattern 264 and a −a-phase (SIN−) that detect movement of the rotating body 18 with a phase difference of 180°. The magnetoresistive pattern 262 is provided, and the B-phase magnetoresistive pattern includes a +b-phase (COS+) magnetic-resistive pattern 263 and a −b-phase (COS−) that detect movement of the rotating body 18 with a phase difference of 180°. The magnetic resistance pattern 261 is provided.

Here, the +a-phase magnetic resistance pattern 264 and the −a-phase magnetic resistance pattern 262 form a bridge circuit similarly to the first magnetic sensing element 171, and one end is connected to the power supply terminal (Vcc). The other end is connected to the ground terminal (GND). Further, a terminal (+a) for outputting the +a phase is provided at the center point of the +a phase magnetic resistance pattern 264, and a −a phase is output at the center point of the −a phase magnetic resistance pattern 262. The terminal (-a) is provided. Further, the +b phase magnetic resistance pattern 263 and the −b phase magnetic resistance pattern 261 constitute a bridge circuit, like the +a phase magnetic resistance pattern 264 and the −a phase magnetic resistance pattern 262, and one end thereof is It is connected to the power supply terminal (Vcc) and the other end is connected to the ground terminal (GND). Further, a terminal (+b) for outputting the +b phase is provided at the center point of the +b phase magnetic resistance pattern 263, and a −b phase is output at the center point of the −b phase magnetic resistance pattern 261. The terminal (-b) is provided.

As shown in FIGS. 8 and 9, the second magnetic sensing element 172 having such a configuration is arranged at a position overlapping the boundary portion of the adjacent tracks 310 in the second magnet 162 in the rotation axis direction L. Therefore, the magnetoresistive patterns 261 to 264 of the second magnetic sensitive element 172 rotate so that the direction thereof changes in the in-plane direction of the track 310 at a magnetic field strength equal to or higher than the saturation sensitivity region of the resistance value of each of the magnetoresistive patterns 261 to 264. A magnetic field can be detected. That is, since the second magnet 162 is provided with a plurality of tracks 310, the track 310 has a magnetic field strength equal to or higher than the saturation sensitivity region of the resistance value of each of the magnetoresistive patterns 261 to 264 at the boundary between adjacent tracks 310. A rotating magnetic field whose direction changes in the in-plane direction is generated. Here, the saturation sensitivity region generally refers to a region other than the region in which the resistance value change amount k can be approximately represented by the equation “k∝H2” with the magnetic field strength H. Further, the principle of detecting the direction of the rotating magnetic field (rotation of the magnetic vector) with the magnetic field strength of the saturation sensitivity region or higher is that the resistance value is set in a state where each of the magnetoresistive patterns 261 to 264 made of ferromagnetic metal is energized. When a magnetic field strength that saturates is applied, the following equation R=R0-k×sin2θ is provided between the angle θ formed by the magnetic field and the current direction and the resistance value R of each of the magnetoresistive patterns 261 to 264.
R0: Resistance value without magnetic field
k: Amount of change in resistance value (a constant when the saturation sensitivity range is exceeded)
The fact that there is a relationship indicated by is used. When the rotating magnetic field is detected based on such a principle, when the angle θ changes, the resistance value R changes along the sine wave, so that the A phase and the B phase with high waveform quality can be obtained.

In the encoder 10 having such a configuration, the amplifier circuits 291-296 and the amplifier circuits 291-296 are provided in the first magnetic sensing element 171, the first hall element 175a, the second hall element 175b, and the second magnetic sensing element 172. A CPU 290 (arithmetic circuit) that performs interpolation processing and various arithmetic processing on the sine wave signals sin and cos output from the first magnetic sensing element 171, the first hall element 175a, the second hall element 175b, Then, based on the output from the second magnetic sensing element 172, the rotational angle position of the rotating body 18 with respect to the substrate unit 13 is obtained.

More specifically, in the encoder 10, when the rotating body 18 makes one rotation, the first magnetic sensitive element 171 outputs the sine wave signals sin and cos shown in FIG. 10 for two cycles. Therefore, after the sine wave signals sin and cos are amplified by the amplifier circuit 291 and the amplifier circuit 292, the CPU 290 can obtain θ=tan−1(sin/cos) from the sine wave signals sin and cos as shown in FIG. Then, the angular position θ of the rotation output shaft can be known. Further, in the present embodiment, the first Hall element 175a and the second Hall element 175b are arranged at positions displaced by 90° from the center of the first magnet 161. Therefore, it is possible to know which of the sine wave signals sin and cos the current position is located. Therefore, the encoder 10 determines the first absolute angular position information of the rotating body 18 based on the detection result of the first magnetic sensing element 171, the detection result of the first hall element 175a, and the detection result of the second hall element 175b. Can be generated and an absolute operation can be performed.

In addition, in the encoder 10 of the present embodiment, the second magnet 162 including the annular magnetized surface 231 in which a plurality of N poles and S poles are alternately magnetized in the circumferential direction is used. Each time the rotating body 18 rotates one cycle of the magnetic pole of the second magnet 162, the second magnetic sensing element 172 facing the 162 outputs sine wave signals sin and cos as shown in FIG. Therefore, if the sine wave signals sin and cos output from the second magnetic sensing element 172 are amplified by the amplifier circuit 293 and the amplifier circuit 294 and then converted into a pulse signal or the like in the CPU 290, they correspond to the magnetic poles of the second magnet 162. Signal is obtained. Therefore, in the CPU 290, the first absolute angle of the rotating body 18 obtained based on the detection result of the first magnetic sensing element 171, the detection result of the first hall element 175a, and the detection result of the second hall element 175b. By using the position information and the detection result of the second magnetic sensing element 172, the second absolute angular position information of the rotating body 18 can be obtained, and the second absolute angular position information is the first absolute angular position information. The resolution is higher than. That is, the first absolute angular position information of the rotating body 18 is detected based on the detection result of the first magnetic sensing element 171, the detection result of the first hall element 175a, and the detection result of the second hall element 175b. By using the first absolute angular position information and the detection result of the second magnetic sensing element 172, the absolute angular position (second absolute angular position information) of the rotating body 18 with higher accuracy is obtained.

(Arrangement of magnets and magnetic sensitive elements in the direction of the rotation axis)
Next, the magnet 16 (the first magnet 161 and the second magnet 162) and the magnetic sensitive element 17 (in the rotation axis direction L) and the magnetic sensitive element 17 (using the schematic view showing the layout of the encoder 10 of the present embodiment from the side direction in FIG. The arrangement of the first magnetic sensing element 171 and the second magnetic sensing element 172) will be described. It should be noted that FIG. 12 is a schematic diagram, and most of the components other than the magnet 16 and the magnetic sensing element 17 are omitted.

As shown in FIG. 12, the length of the second magnetic sensing element 172 on the output side L1 in the rotation axis direction L from the output side substrate surface 60b is measured from the output side substrate surface 60b of the first magnetic sensing element 171. It is longer than the length on the output side L1 in the rotation axis direction L. In other words, the second magnetic sensing element 172 projects in the rotation axis direction L toward the output side L1 which is the magnet side of the first magnetic sensing element 171. Therefore, the gap between the second magnetism sensing element 172 and the second magnet 162, which is required to be narrow because the number of magnetizations is large and the magnetic flux does not reach far, can be easily narrowed. Further, since the first magnetic sensitive element 171 and the second magnetic sensitive element 172 are both mounted on the substrate 60, the substrate unit 13 can be easily assembled. Therefore, the motor 1 of the present embodiment can be easily formed and has high magnetic detection sensitivity. The first magnetic sensitive element 171 and the second magnetic sensitive element 172 are preferably mounted on the substrate 60 by resin molding or flip-chip mounted on the substrate 60.

As shown in FIG. 12, the distance between the first magnetic sensing element 171 and the first magnet 161 is wider than the distance between the second magnetic sensing element 172 and the second magnet 162. Since the second magnet 162 has a larger number of magnetizations than the first magnet 161, and the magnetic flux does not reach as far as the first magnet 161, the second magnetic sensing element 172 and the second magnetism detecting element 172 are provided as in the motor 1 of the present embodiment. By making the distance between the magnet 162 and the first magnetism sensing element 171 smaller than the distance between the first magnetism sensing element 171 and the first magnetism sensing element 161, both the first magnetism sensing element 171 and the second magnetism sensing element 172 can detect magnetism with high sensitivity. Will be possible.

Further, as described above, the substrate 60 has the signal ground 5 connected to the ground terminals 6 and 7 of the first magnetic sensing element 171 and the second magnetic sensing element 172, and the substrate holder 50 has the rotation axis line. The opening 58 is provided at the position of the second magnetic sensing element 172 when viewed from the direction L. Further, as shown in FIG. 12, the opening 58 is covered with a shield member 80 having a thickness in the rotation axis direction L smaller than that of the substrate holder 50. Then, as described above, the substrate holder 50 and the shield member 80 are both formed of a conductive member (conductive metal) and are connected to the signal ground 5. As described above, by shielding the second magnetic sensing element 172 with the thin shield member 80, the second magnetic sensing element 172 is provided on the magnet 16 side while keeping the distance between the second magnetic sensing element 172 and the second magnet 162 narrow. Noise (frame ground noise, power supply noise, etc.) from entering the device can be prevented from affecting the magnetic detection result. Moreover, the shield effect can be easily adjusted by using the shield member 80 as a separate member from the substrate holder 50.

As shown in FIG. 12, the position of the first magnetic sensing element 171 facing the first magnet 161 is covered with the substrate holder 50. With such a configuration, the motor 1 of the present embodiment suppresses noise from entering the first magnetic sensing element 171 from the magnet 16 side and affecting the magnetic detection result.

In the present embodiment, the opening is not provided at the position of the first magnetic sensing element 171, and the position of the first magnetic sensing element 171 is not covered with the shield member 80 because there is no opening. An opening may be provided at the position of the first magnetic sensing element 171, and the shield member 80 may be provided to cover the opening. In the case of such a configuration, the opening at the position of the first magnetic sensing element 171 and the opening 58 at the position of the second magnetic sensing element 172 may be covered with one shield member 80.

Here, it is preferable that the second magnetic sensing element 172 does not protrude beyond the substrate holder 50 toward the second magnet 162 side. This is because it is possible to prevent the second magnetic sensing element 172 from contacting another member or the like. Further, when the shield member 80 is attached to the substrate holder 50, the shield member 80 can be easily attached without being deformed. In the present embodiment, the surface of the second magnetic sensing element 172 on the second magnet 162 side is substantially flush with the surface of the substrate holder 50 on the second magnet 162 side (to be exact, the shield mounting surface 59). ..

Further, as shown in FIG. 12, the second magnetic sensing element 172 of this embodiment has a magnetic sensing film 172a. The arrangement of the magnetic sensitive film 172a on the second magnetic sensitive element 172 in the rotation axis direction L is on the second magnet 162 side (close to the output side L1). That is, the position of the magnetic sensitive film 172a on the second magnetic sensing element 172 in the rotation axis direction L is closer to the second magnet 162 side than the center of the second magnetic sensing element 172 in the rotation axis direction L. In this way, by bringing the position of the magnetic sensitive film 172a close to the magnet 16, it becomes possible to perform magnetic detection with a particularly high sensitivity.

In the motor 1 of the present embodiment, as shown in FIG. 6 and FIG. 8, the second magnet 162 is arranged around the first magnet 161, and the first magnet 161 and the second magnet 162 are separated from each other. In between, a shield wall 153 is provided over the entire circumference. The shield wall 153 is integrally molded with the magnet holding portion 151 and the fixed portion 152, and suppresses the influence of the magnetic flux traveling from the first magnet 161 to the second magnet 162. Here, it is preferable that the shield wall 153 does not project beyond the second magnet 162 toward the substrate 60 side unlike the motor 1 of the present embodiment shown in FIG. By providing the shield wall 153 that does not exceed the second magnet 162 between the first magnet 161 and the second magnet 162, it is possible to suppress the influence of the magnetic flux traveling from the first magnet 161 to the second magnet 162, and This is because it is possible to prevent the magnetic flux of 162 from heading to the shield wall 153 and weakening of the magnetic flux heading to the second magnetic sensing element 172. In the present embodiment, the surface of the shield wall 153 and the surface of the second magnet 162 on the opposite output side L2 are flush with each other, but the surface of the second magnet 162 on the opposite output side L2 is the opposite output of the shield wall 153. It may project to the opposite output side L2 from the surface of the side L2.

Further, the shield wall 153 preferably protrudes beyond the first magnet 161 to the opposite output side L2 which is the substrate 60 side, as in the motor 1 of the present embodiment shown in FIG. This is because the shield wall 153 protruding beyond the first magnet 161 to the opposite output side L2 can suppress the influence of the magnetic flux traveling from the first magnet 161 to the second magnet 162.

The second magnet 162 may be magnetized in advance and fixed to the magnet holder 15, but it is more preferable that the second magnet 162 is magnetized in a state of being fixed to the magnet holder 15. This is because center deviation of the second magnet 162 with respect to the rotary shaft 2 (encoder-side rotary shaft 22) can be suppressed. Here, in order to improve the magnetizability, it is preferable that the shield wall 153 does not protrude beyond the second magnet 162 in the rotation axis direction L as in the present embodiment. It should be noted that the second magnet 162, which is not displaced from the center of the second magnet 162 with respect to the rotation shaft 2 despite the displacement of the second magnet 162 with respect to the magnet holder 15, is attached to the magnet holder 15 in a fixed state. It can be judged that it is magnetized.

The present invention is not limited to the above-described embodiments, but can be implemented in various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments corresponding to the technical features in each mode described in the section of the summary of the invention are to solve some or all of the above-mentioned problems, or one of the effects described above. It is possible to appropriately replace or combine in order to achieve a part or all.
If the technical features are not described as essential in this specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 1... Motor, 2... Rotating shaft, 3... Motor main body, 4... Motor case, 5... Signal ground, 6... Ground terminal, 7... Ground terminal, 10... Encoder, 11... Outer case, 12... Encoder cover, 13... Substrate unit, 14... Encoder holder, 15... Magnet holder, 16... Magnet, 17... Magnetism sensitive element, 18... Rotating body, 21... Motor side rotating shaft, 22... Encoder side rotating shaft, 41... Cylindrical case, 42... Bearing holder, 43... Bearing, 44... Circular recess, 45... Flange, 46... Annular wall, 47... Plate, 48... Through hole, 49... Notch, 50... Substrate holder, 51... Boss part, 52... Boss part, 53... End plate portion, 54... Side plate portion, 57... Shield member mounting position, 58... Opening portion (through hole), 59... Shield mounting surface, 60... Board, 60a... Counter-output side board surface, 60b... Output board Surface, 61... Notch, 62... Fixing hole, 63... Fixing hole, 65... Connector, 70... Fixing member, 80... Shield member, 111... End plate part, 112... Side plate part, 113... Notch, 114... Seal Member... 121... End plate part, 122... Cylindrical part, 123... Notch, 141... Magnet arrangement hole, 142... Body part, 143... Leg part, 144... Fixing hole, 151... Magnet holding part, 152... Fixing part , 153... Shield wall, 161... First magnet, 162... Second magnet, 171... First magnetic sensitive element, 172... Second magnetic sensitive element, 172a... Magnetic sensitive film, 175... Hall element, 175a... First hole Element 175b... Second hall element, 221... Magnetized surface, 231... Magnetized surface, 241... Magnetic resistance pattern, 242... Magnetic resistance pattern, 243... Magnetic resistance pattern, 244... Magnetic resistance pattern, 261... Magnetic resistance pattern , 262... Magnetoresistive pattern, 263... Magnetoresistive pattern, 264... Magnetoresistive pattern, 290... CPU, 291... Amplifier circuit, 292... Amplifier circuit, 293... Amplifier circuit, 294... Amplifier circuit, 295... Amplifier circuit, 296... Amplifier circuit, 310... Track, 621... Ground through hole, L... Rotation axis line, L1... Output side, L2... Counter output side

Claims (9)

A first magnet magnetized with one N pole and a second magnet magnetized with one S pole, and a second magnet magnetized with a plurality of N poles and S poles, and each of the first magnet and the second magnet A magnet holder that can rotate with both magnets,
A first magnetic sensing element provided facing the first magnet in the rotation axis direction of the magnet holder, and a second magnetic sensing element provided facing the second magnet in the rotation axis direction are mounted. And the board
Equipped with
The motor according to claim 2, wherein the second magnetic sensing element projects toward the magnet side more than the first magnetic sensing element. The motor according to claim 1,
A substrate holder that covers the substrate on the magnet side in the rotation axis direction;
The substrate has a signal ground connected to the ground terminals of the first magnetic sensing element and the second magnetic sensing element,
The substrate holder has an opening at the position of the second magnetic sensing element when viewed from the rotation axis direction,
The opening is covered with a shield member whose thickness in the rotation axis direction is thinner than that of the substrate holder,
The substrate holder and the shield member are both formed of a conductive member and are connected to the signal ground. The motor according to claim 2,
A motor, wherein a position of the first magnetic sensing element facing the first magnet is covered with the substrate holder. The motor according to any one of claims 1 to 3,
The motor according to claim 2, wherein the second magnetic sensing element does not protrude beyond the substrate holder toward the second magnet. The motor according to any one of claims 1 to 4,
A motor characterized in that a distance between the second magnetic sensing element and the second magnet is narrower than a distance between the first magnetic sensing element and the first magnet. The motor according to any one of claims 1 to 5,
The second magnetic sensing element has a magnetic sensing film,
The motor, wherein the position of the magneto-sensitive film in the second magneto-sensitive element in the rotation axis direction is closer to the second magnet than the center of the second magneto-sensitive element in the rotation axis direction. The motor according to any one of claims 1 to 6,
The second magnet is arranged around the first magnet,
A shield wall is provided over the entire circumference between the first magnet and the second magnet,
The motor, wherein the shield wall does not protrude beyond the second magnet toward the substrate. The motor according to claim 7,
The motor, wherein the shield wall protrudes toward the substrate beyond the first magnet. The motor according to any one of claims 1 to 8,
The motor is characterized in that the second magnet is magnetized while being fixed to the magnet holder.

Images