Motor

Abstract

[Problem] To provide a motor that is miniaturized in the rotational axis direction. [Solution] An axial-gap-type motor 1 comprises a magnet 10 that is formed in a ring shape, and a substrate 20 (member) that has a coil 31 facing the magnet 10. A first coating film 11 and a second coating film 41 that are composed of a fluororesin coating are formed on the coil-facing surface 12 of the magnet 10 and the magnet-facing surface 42 of the coil 31, and a magnetic gap is formed in the rotational axis direction A between the magnet 10 and the coil 31 with the first coating film 11 and the second coating film 41 interposed therebetween. Therefore, the motor 1 can be miniaturized in the rotational axis direction A.

Description

motor

[0001] The present invention relates to a motor.

[0002] Patent Document 1 discloses an aperture drive mechanism (aperture adjustment device) that functions as a linear motor when a current flows through the aperture drive coil 31, generating a magnetic force between the aperture drive magnet 28 and the aperture drive coil 31 in a direction along the guide shaft 26.

[0003] Japanese Patent Application Laid-Open No. 2021-021846

[0004] The linear motor (hereinafter referred to as the "conventional motor") configured in the aperture drive mechanism described in Patent Document 1 has the aperture drive coil 31 embedded in one side of the base frame 4, making it difficult to reduce the size of the aperture drive mechanism in the direction of the optical axis A.

[0005] An object of the present invention is to reduce the size of the motor in the direction of the rotation axis.

[0006] The motor of the present invention comprises a magnet and a member having one or more coils in contact with the magnet in the direction of the rotation axis, and a coating having a predetermined surface roughness is formed on the surface of the magnet on the member side or the surface of the member on the magnet side, and the magnet or the coil is rotatable relative to the coating.

[0007] According to the present invention, it is possible to provide a motor that is miniaturized in the direction of the rotation axis.

[0008] 1 is an explanatory diagram of a first embodiment, showing a perspective view of a motor illustrating a magnet and a substrate; FIG. 1 is an explanatory diagram of a first embodiment, showing a plan view of a motor illustrating a magnet and a substrate; FIG. 1 is an explanatory diagram of a first embodiment, showing a conceptual diagram of a motor showing a cross section taken along a plane including the motor rotation shaft; FIG. 1 is an explanatory diagram of a first embodiment, showing a perspective view of an aperture adjustment device; FIG. 1 is an explanatory diagram of a first embodiment, showing an exploded perspective view of an aperture adjustment device; FIG. 2 is an explanatory diagram of a first embodiment, showing a cross section taken along a plane including the motor rotation shaft of the aperture adjustment device shown in FIG. 5; FIG. 2 is an explanatory diagram of a first embodiment, showing a state in which the opening area of ​​an opening formed by a blade is increased; FIG. 3 is an explanatory diagram of a first embodiment, showing a state in which the opening area of ​​an opening formed by a blade is decreased; FIG. 3 is an explanatory diagram of a second embodiment, showing a conceptual diagram of a motor showing a cross section taken along a plane including the motor rotation shaft; FIG. 4 is an explanatory diagram of a fourth embodiment, showing a conceptual diagram of a motor showing a cross section taken along a plane including the motor rotation shaft; FIG. 5 is an explanatory diagram of a fifth embodiment, showing a conceptual diagram of a motor showing a cross section taken along a plane including the motor rotation shaft; and FIG. 5 is an explanatory diagram of a fifth embodiment, showing a conceptual diagram of a layer including a plurality of particles with fine particle diameters formed between a first coating and a second coating.

[0009] (First Embodiment) A first embodiment of the present invention will be described with reference to the accompanying drawings. In the first embodiment, a motor 1 for driving a plurality of (six in the first embodiment) blades 81-81 (weights) incorporated in a camera aperture adjustment device 50 (see FIG. 4) is illustrated. With reference to FIGS. 1 to 3, the motor 1 includes a ring-shaped magnet 10 and a substrate 20 (member) having a coil 31 disposed opposite the magnet 10 in a direction A along the rotation axis L of the motor 1 (the "up-down direction" in FIG. 3, hereinafter referred to as the "rotation axis direction A").

[0010] The magnet 10 includes a rare earth magnet, and has an average crystal grain size set to 0.01 μm or more and 1.0 μm or less. If the average crystal grain size of the magnet 10 is smaller than 0.01 μm, the magnet 10 may become amorphous and exhibit no magnetic properties. On the other hand, if the average crystal grain size of the magnet 10 is larger than 1.0 μm, the magnetic properties may be degraded. The thickness H (see FIG. 3) of the magnet 10 is set to 1.0 mm or less (not including 0 mm or less). The mass of the magnet 10 is 0.1 g or less (not including 0 g or less). Note that the mass of the magnet 10 in the first embodiment is 0.056 g.

[0011] Here, the magnetic material used for magnet 10 can be anisotropic magnetic powder or isotropic magnetic powder. Here, when magnetic properties are prioritized, anisotropic magnetic powder such as MQA grade Magnequench (registered trademark) manufactured by Neo Performance Materials or MAGFINE (registered trademark) manufactured by Aichi Steel Corporation is suitable. On the other hand, for applications in which the rotation speed of motor 1 is 100 rpm or higher, isotropic magnetic powder such as MQP grade Magnequench (registered trademark) manufactured by Neo Performance Materials is suitable. This is because, as the rotation speed of motor 1 increases, a reverse current that cancels out the current originally applied to coil 31 is generated, resulting in a problem of reduced efficiency of motor 1. Therefore, when the rotation speed of motor 1 is 100 rpm or higher, it is preferable to use isotropic magnetic powder, which reduces back electromotive force.

[0012] The magnet 10 has a first coating 11 formed on the magnet 10 side on a surface 12 facing the coil 31 (hereinafter referred to as the "coil-facing surface 12"). The first coating 11 is a fluororesin coating made of a fluorine-containing resin such as PTFE (Poly Tetra Fluoro Ethylene) or PFA (Perfluoro Alkoxy Alkane). The first coating 11 has a thickness of 5 μm or less (excluding thicknesses of 0 μm or less). The thickness of the first coating 11 (fluororesin coating) is 10 to 100 nm when coated by paint application and 1000 to 2000 nm when coated by vacuum deposition. The surface roughness (RSm) of the first coating 11 is smaller than the surface roughness of the coil-facing surface 12 of the magnet 10.

[0013] A circuit board such as a flexible printed circuit board is applied to the substrate 20. The substrate 20 has a substrate main body 21 configured from an insulating plate, and a circuit section 30 formed on a surface 22 of the substrate main body 21 facing the magnet 10 (hereinafter referred to as the "magnet-facing surface 22"). The circuit section 30 has a coil 31, a plurality of (four in the first embodiment) lands 35A-35D, and a plurality of (four in the first embodiment) connection sections 36A-36D.

[0014] The coil 31 includes a first coil group 33 and a second coil group 34 as multiple coils arranged in a fixed pattern on the substrate main body 21. One end of the first coil group 33 is connected to a land 35A via a connection portion 36A, and the other end is connected to a land 35B via a connection portion 36B. One end of the second coil group 34 is connected to a land 35C via a connection portion 36C, and the other end is connected to a land 35D via a connection portion 36D. The coil 31 is configured such that the first coil group 33 is positioned further outward than the second coil group 34 in the radial direction R (hereinafter referred to as the "radial direction R") of a circle centered on the rotation axis L. In this manner, the coil 31 is configured so that the first coil group 33 and the second coil group 34 do not intersect with each other, in other words, so that the first coil group 33 and the second coil group 34 do not come into electrical contact with each other.

[0015] The coils 31 (first coil group 33 and second coil group 34) have a second coating 41 on the coil 31 side formed on a surface 42 facing the magnet 10 (the surface of the member on the magnet 10 side, hereinafter referred to as the "magnet-facing surface 42"). The second coating 41 is made of a fluororesin coating. The surface roughness (RSm) of the second coating 41 is 100 nm or less (not including 0 nm or less). In the motor 1, the static friction coefficient or dynamic friction coefficient between the second coating 41 on the coil 31 side and the first coating 11 on the magnet 10 side is 0.2 or less (not including 0 nm or less). In this way, the motor 1 is an axial gap motor in which a magnetic gap is formed between the magnet 10 and the coils 31 in the rotation axis direction A via the first coating 11 and second coating 41.

[0016] When AC voltage is applied between land 35A and land 35B by AC power supply 3 (see FIG. 7), an S pole is formed in each portion of coil 31 that faces the S pole of magnet 10, and an N pole is formed in each portion of coil 31 that faces the N pole of magnet 10. As a result, the repulsive force of the magnetic poles causes magnet 10 to rotate in one direction around rotation axis L, and the magnetic pole of magnet 10 and the magnetic pole of each portion of coil 31 become opposite, forming a magnetic circuit by magnet 10 and coil 31.

[0017] Meanwhile, an AC voltage having a phase difference of 90 degrees with respect to the AC voltage applied between land 35A and land 35B is applied between land 35C and land 35D by AC power supply 3 (see FIG. 7). As a result, the magnetic poles of magnet 10 and the magnetic poles of each part of coil 31 become the same, and magnet 10 rotates in one direction about rotation axis L due to the repulsive force of the magnetic poles, and the magnetic poles of magnet 10 and the magnetic poles of each part of coil 31 become opposite to each other, thereby forming a magnetic circuit by magnet 10 and coil 31.

[0018] Here, when motor 1 is rotating, the thickness of the air layer formed between first coating 11 formed on coil-facing surface 12 of magnet 10 and second coating 41 formed on magnet-facing surface 42 of coil 31 is 100 nm or less (excluding thicknesses of 0 nm or less). Furthermore, the aspect ratio of motor 1, i.e., the ratio of thickness to outer diameter of motor 1, is 0.05 or more and 0.2 or less. Furthermore, the torque of motor 1 is 20 μN or more when the drive current is 300 mA, which is greater than the static friction force or kinetic friction force generated between first coating 11 formed on coil-facing surface 12 of magnet 10 and second coating 41 formed on magnet-facing surface 42 of coil 31.

[0019] Next, an aperture adjustment device 50 including a motor 1 will be described with reference to Figures 4 to 8. The aperture adjustment device 50 has a housing 51, a rotor 71 (weight), and a plurality of (six in the first embodiment) blades 81-81 (weights). The housing 51 has a base 53 and a cover 63. The housing 51 has an internal space 52 (see Figure 6) defined by the base 53, the cover 63, and the board main body 21. The internal space 52 accommodates a magnet 10, the rotor 71, and a plurality of blades 81-81.

[0020] The base 53 is formed in a rectangular shape when viewed in the rotational axis direction A. The base 53 has a hole (hereinafter referred to as the "axial hole 54") penetrating in the rotational axis direction A, a small-diameter recess 55 formed on the opening periphery on one side in the rotational axis direction A (the "upper side" in FIG. 5) of the axial hole 54, a large-diameter recess 56 formed on the opening periphery on one side in the rotational axis direction A of the small-diameter recess 55, and a notch 57 formed to surround the lands 35A-35D on the substrate main body 21. The opening peripheries on one side in the rotational axis direction A of the axial hole 54, the small-diameter recess 55, and the large-diameter recess 56 are formed in a circular shape coaxial with the rotational axis L.

[0021] The magnet 10 and the rotor 71 are housed in the shaft hole 54 of the base 53. A coating 15 (see FIG. 3) equivalent to that on the coil-facing surface 12 is formed on the outer peripheral surface 13 (side surface) of the magnet 10. The base 53 has a plurality of pins 58-58 (six in the first embodiment) formed on the bottom surface (reference numeral omitted) of the small-diameter recess 55. The plurality of pins 58-58 are arranged at equal intervals (at 60-degree intervals in the first embodiment) on a circle (circumferential direction) centered on the rotation axis L.

[0022] The rotor 71 is formed of a ring-shaped plate having the same outer and inner diameters as the magnet 10. The rotor 71 is fixed coaxially to the magnet 10 by adhesive or the like to the rotor mounting surface 14 of the magnet 10 (the surface opposite the coil opposing surface 12 in the rotation axis direction A). The rotor 71 has a plurality (six in the first embodiment) of pins 73-73 formed on a surface 72 (hereinafter referred to as the "blade opposing surface 72") on the opposite side in the rotation axis direction A from the surface (joint surface) facing the magnet 10. The plurality of pins 73-73 are arranged at equal intervals (at "60-degree intervals" in the first embodiment) on a circle (circumferential direction) centered on the rotation axis L.

[0023] The cover 63 is formed of a ring-shaped plate. The cover 63 has a surface (hereinafter referred to as a "two-face width portion 64") that is formed to match the shape of the base 53 and extends radially in the rotation axis direction A. The cover 63 has a plurality of (six in the first embodiment) pin holes 65-65 arranged at equal intervals (at "60-degree intervals" in the first embodiment) on a circle (circumferential direction) centered on the rotation axis L. Corresponding pins 58-58 provided on the base 53 are fitted into the pins 73-73. The cover 63 has a plurality of (six in the first embodiment) elongated holes 66-66 arranged at equal intervals (at "60-degree intervals" in the first embodiment) on a circle centered on the rotation axis L and extending along the circle. Corresponding pins 73-73 provided on the rotor 71 are fitted into the elongated holes 66-66.

[0024] The vanes 81-81 are provided between the cover 63 and the rotating body 71 and are arranged to surround (along) the axial hole 54 formed in the base 53 of the housing 51. As shown in FIG. 7, pin holes 82-82 are formed on one side (the "clockwise side" in FIG. 7) of the vanes 81-81 in a direction along the axial hole 54 (see FIG. 5) (hereinafter referred to as the "circumferential direction C"; see FIG. 7), into which corresponding pins 58-58 provided in the base 53 are fitted. The vanes 81-81 have elongated holes 83-83 formed on the other side (the "counterclockwise side" in FIG. 7) of the pin holes 82-82 in the circumferential direction C, extending in an arc. Corresponding pins 73-73 provided in the rotating body 71 are fitted into the elongated holes 83-83 of the vanes 81-81. The total weight of the plurality of blades 81-81 (weights) is heavier than the weight of the magnet 10.

[0025] In aperture adjustment device 50, when AC voltages with a phase difference of 90 degrees are applied by AC power supply 3 to first coil group 33 and second coil group 34 of motor 1, magnet 10 and rotor 71 rotate together in the counterclockwise direction in FIG. 8 around rotation axis L. This causes pins 73-73 of rotor 71 to move from one circumferential side to the other circumferential side within corresponding elongated holes 83-83 of blades 81. As a result, blades 81-81 rotate in the clockwise direction in FIG. 8 around pins 58-58 of base 53, and as shown in FIG. 7, the opening area of ​​opening 85 formed by the plurality of blades 81-81 increases.

[0026] On the other hand, when AC voltages shifted by 90 degrees are applied from AC power supply 3 to first coil group 33 and second coil group 34 of motor 1 so that magnet 10 and rotor 71 rotate together in the clockwise direction in FIG. 7 around rotation axis L, pins 73-73 of rotor 71 move from the other circumferential side to one circumferential side within corresponding elongated holes 83-83 of blades 81. As a result, blades 81-81 rotate counterclockwise in FIG. 7 around pins 58-58 of base 53, and the opening area of ​​opening 85 formed by the plurality of blades 81-81 decreases, as shown in FIG. 8. In this way, aperture adjustment device 50 adjusts the amount of light incident on a camera lens unit (not shown) by varying the opening area of ​​opening 85 formed by the plurality of blades 81-81.

[0027] In conventional motors, the coil is embedded in the side surface of the base of the housing, making it difficult to reduce the size of the aperture adjustment device in the direction of the rotation axis.

[0028] In contrast, in the first embodiment, an axial gap motor 1 is configured, which includes a ring-shaped magnet 10 and a substrate 20 (member) having a coil 31 facing the magnet 10. A first coating 11 and a second coating 41 formed by fluororesin coating are formed on the coil-facing surface 12 of the magnet 10 and the magnet-facing surface 42 of the coil 31, respectively. A magnetic gap is formed between the magnet 10 and the coil 31 in the rotation axis direction A via the first coating 11 and the second coating 41. According to the first embodiment, the motor 1 can be made smaller in the rotation axis direction A, and thus the aperture adjustment device 50 incorporating the motor 1 can also be made smaller. Furthermore, in the first embodiment, the magnet 10 and the rotor 71 (weight) are housed in the shaft hole 54 formed in the base 53 of the housing 51, which prevents the magnet 10 from shifting relative to the coil 31 when the motor 1 is not rotating. In addition, in the first embodiment, a coating 15 equivalent to the coil opposing surface 12 is formed on the outer surface 13 (side surface) of the magnet 10, so that when the motor 1 rotates, it is possible to reduce the contact resistance when the rotating part (magnet 10) and the non-rotating part (housing 51) come into contact, and torque fluctuations of the motor 1 can be suppressed.

[0029] Second Embodiment Next, a second embodiment will be described with reference to Fig. 9. Note that the same names and symbols are used for parts common to the first embodiment, and duplicated descriptions will be omitted. In the first embodiment, the substrate 20 (motor 1) is configured by arranging the coil 31 on the magnet-facing surface 22 of the substrate main body 21.

[0030] In contrast, in the second embodiment, the substrate 20 (motor 1) is configured by arranging the coil 31 on the surface 23 of the substrate body 21 opposite the magnet-facing surface 22 in the rotation axis direction A. In this case, the second coating 41 is formed on the magnet-facing surface 22 of the substrate body 21 on the coil 31 side. According to the second embodiment, it is possible to obtain the same effects as those of the first embodiment described above.

[0031] Third Embodiment Next, a third embodiment will be described with reference to Fig. 10. The same names and symbols are used for parts common to the first embodiment, and duplicated descriptions will be omitted. In the first and second embodiments, the substrate 20 having the coil 31 is fixed to the base 53 of the housing 51, and the motor 1 is configured so that the magnet 10 rotates about the rotation axis L relative to the substrate 20.

[0032] In contrast, in the third embodiment, the magnet 10 is fixed to the base 53 (see FIG. 6) of the housing 51, and the motor 1 is configured so that the substrate 20 rotates around the rotation axis L relative to the magnet 10. In this case, the rotor 71 (see FIG. 5) is fixed by adhesive or the like to the surface 23 of the substrate main body 21 opposite the magnet-facing surface 22 in the rotation axis direction A, and a plurality of blades 81-81 (weights) are arranged between the rotor 71 and the cover 63 (see FIG. 5), thereby configuring the aperture adjustment device 50. According to the third embodiment, it is possible to obtain the same effects as those of the first embodiment described above.

[0033] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Fig. 11. Note that the same names and symbols are used for parts common to the third embodiment, and duplicated descriptions will be omitted. In the third embodiment, a rotor 71 (see Fig. 5) is fixed by adhesive or the like to the surface 23 of the substrate main body 21 opposite the magnet-facing surface 22.

[0034] In contrast to this, in the fourth embodiment, the coil 31 is disposed on the surface 23 of the substrate main body 21 opposite the magnet-facing surface 22 in the rotation axis direction A, the rotor 71 (see FIG. 5) is fixed by adhesive or the like to the surface 43 of the coil 31 opposite the magnet-facing surface 42 (the joint surface with the substrate main body 21) in the rotation axis direction A, and a plurality of blades 81-81 (weights) are disposed between the rotor 71 and the cover 63 (see FIG. 5), thereby configuring the aperture adjustment device 50. According to the fourth embodiment, it is possible to obtain the same effects as those of the first embodiment described above.

[0035] Next, a fifth embodiment will be described with reference to Figures 12 and 13. The same names and symbols are used for parts common to the first embodiment, and duplicated descriptions will be omitted. In the first embodiment, the motor 1 was configured so that the first coating 11 formed on the coil-facing surface 12 of the magnet 10 and the second coating 41 formed on the magnet-facing surface 42 of the coil 31 contacted (sliding) with each other.

[0036] In contrast, in the fifth embodiment, the motor 1 is configured by forming a layer 45 of a fine particle size lubricant between the first coating 11 on the magnet 10 side and the second coating 41 on the coil 31 side. The lubricant is configured, for example, of a stearic acid-based lubricant in solid powder form, such as calcium stearate, zinc stearate, or magnesium stearate. The multiple fine particle size particles that make up the lubricant come into contact with the first coating 11 and the second coating 41 and have the property of being electrically charged.

[0037] The fifth embodiment achieves the same effects as the first embodiment. Furthermore, in the fifth embodiment, a layer 45 of fine-particle lubricant is formed between the first coating 11 on the magnet 10 side and the second coating 41 on the coil 31 side. This reduces the contact area between the magnet 10 and the coil 31 compared to the first embodiment, in which the first coating 11 and the second coating 41 are in surface contact, causing relative rotation between the magnet 10 and the coil 31. As a result, the fifth embodiment reduces friction between the first coating 11 and the second coating 41, thereby reducing torque fluctuations and improving the efficiency of the motor 1. Furthermore, in the fifth embodiment, a lubricant capable of being charged is used in the layer 45, preventing solid powder lubricant from scattering around due to electrostatic force generated by the lubricant during rotation of the motor 1.

[0038] The embodiment is not limited to the above-described embodiment, and may be configured as follows, for example. In the above-described embodiment, the first coating 11 on the magnet 10 side and the second coating 41 on the coil 31 side are configured with a fluororesin coating. Alternatively, either or both of the first coating 11 and the second coating 41 may be configured with a DLC (Diamond-Like-Carbon) coating. In other words, one of the first coating 11 and the second coating 41 may be configured with a fluororesin coating, and the other may be configured with a DLC (Diamond-Like-Carbon) coating. Here, the static or dynamic friction coefficient of the DLC coating is 0.2, the thickness of the DLC coating is 2 μm, and the surface roughness is 10 μm.

[0039] REFERENCE SIGNS LIST 1 Motor, 10 Magnet, 11 Coating, 12 Coil facing surface (magnet surface on the member side), 20 Substrate (member), 22 Magnet facing surface (magnet surface on the member side), 31 Coil, 41 Coating

Claims

A magnet and a member having one or more coils in contact with the magnet in the rotation axis direction, a coating having a predetermined surface roughness is formed on a surface of the magnet on the member side or a surface of the member on the magnet side; the magnet or the coil is rotatable relative to the coating; Motor. The static or dynamic friction coefficient of the coating is 0.2 or less. The motor according to claim 1 . The coating is a resin containing fluorine.

3. The motor according to claim 1 or 2. The thickness of the coating is 5 μm or less.

3. The motor according to claim 1 or 2. the surface roughness of the coating is smaller than the surface roughness of the magnet; 3. The motor according to claim 1 or 2. The surface roughness of the coating formed on the surface of the member on the magnet side is 100 nm or less. The motor according to claim 5. The magnet and the coil are rotatable through air, The thickness of the air layer is 100 nm or less.

3. The motor according to claim 1 or 2. The thickness of the magnet is 1.0 mm or less.

3. The motor according to claim 1 or 2. a torque generated by the interaction of the magnetic force of the magnet and the current flowing through the coil is greater than a static friction force or a kinetic friction force between the magnet and the coil; 3. The motor according to claim 1 or 2. The mass of the magnet is 0.1 g or less. The motor according to claim 9. the magnet has a side surface extending in the direction of the rotation axis, The coating is formed on the side surface.

3. The motor according to claim 1 or 2. The magnet has an average crystal grain size in the range of 0.01 μm or more and 1.0 μm or less.

3. The motor according to claim 1 or 2. The ratio of the thickness of the motor to the outer diameter of the motor (thickness of the motor / outer diameter of the motor) is 0.05 or more and 0.2 or less, and the torque is 20 μN or more.

3. The motor according to claim 1 or 2. A weight is provided on one of the magnet and the member that serves as a rotating body.

3. The motor according to claim 1 or 2. The weight is heavier than the magnet.

15. The motor of claim 14. a torque generated by the interaction of the magnetic force of the magnet and the current flowing through the coil is greater than a static friction force or a kinetic friction force between the magnet and the coil; 16. The motor according to claim 14 or 15. The coating is a DLC coating.

3. The motor according to claim 1 or 2. a first coating is formed on the surface of the magnet on the member side; a second coating is formed on the surface of the magnet facing the member; the magnet is rotatable relative to one or more of the coils; a layer including a plurality of particles is formed between the first coating and the second coating; The motor according to claim 1 . the plurality of particles are a compound comprising stearic acid; 20. The motor of claim 18. the plurality of particles are in contact with the first coating or the second coating; the plurality of particles are electrically charged; 20. A motor according to claim 18 or 19.

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