Motor

Abstract

A motor (1) is provided with a stator (4) and a rotor (3), a conductive stator holding section (10) for holding the stator (4), a circuit board (5), and a fastening screw (6) having a head section and a screw body section, the fastening screw (6) being screwed into the stator holding section (10) in a state in which the screw body section is screwed into the stator holding section (10). The head portion is held in a state in which the circuit board (5) is sandwiched between the head portion and the stator holding portion (10), and is in contact with both the frame ground portion of the circuit board (5) and the stator holding portion (10).

Description

Technical Field

[0001] The present invention relates to a motor. Background Art

[0002] Conventionally, as a method for fixing a circuit board to a stationary part of a motor, a method using pins is known. For example, according to Patent Document 1, the circuit board is fixed to an insulating part of a stator by a plurality of connecting pins.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: WO2019 / 127226 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, as shown in Patent Document 1, when a circuit board is connected to a stationary part of a motor using connecting pins, there are cases where the connection strength is insufficient. In response to this, although it is possible to consider welding the connecting pins to the circuit board to enhance the fixing strength, the operation process becomes complicated.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a motor having excellent durability without performing complicated operations.

[0009] Means for Solving the Problems

[0010] An exemplary motor of the present invention is characterized by including: a stator having a plurality of coil parts arranged along a circumferential direction; a rotor provided so as to cover a radially outer side of the stator and capable of rotating about a central axis extending in an axial direction; a conductive stator holding part having a cylindrical part, a base part, and an outer wall part, the cylindrical part having an outer peripheral surface in contact with an inner peripheral surface of the stator, the base part extending radially outward from a lower side part of the cylindrical part, and the outer wall part extending downward from an outer side part of the base part; a circuit board fixed relative to the stator holding part; and a conductive fastening screw having a head and a screw body part, and in a state where the screw body part is screwed to the stator holding part, holding the circuit board in a state where the head and the stator holding part sandwich the circuit board, and contacting both a frame grounding part of the circuit board and the stator holding part.

[0011] Effects of the Invention

[0012] According to the present invention, a motor having excellent durability can be provided. Description of the Drawings

[0013] Figure 1It is a cross-sectional view schematically showing the motor related to the embodiment.

[0014] Figure 2 It is a view observed from the A-A direction Figure 1 of the figure.

[0015] Figure 3 It is a top view of the circuit board.

[0016] Figure 4 It is a bottom view of the circuit board.

[0017] Figure 5 It is Figure 1 an enlarged view near the fastening screw in

[0018] Symbol Explanation

[0019] 1... Motor, 2... Shaft, 3... Rotor, 4... Stator, 5... Circuit board, 6... Fastening screw, 10... Bracket (stator holding part), 11... Cylindrical part, 12... Base part, 13... Outer wall part, 45... Coil part, 51... Frame grounding part, 61... Head, 62... Screw body part, CA... Central axis. Detailed Embodiment

[0020] Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings.

[0021] First, in this specification, the rotation axis of the motor 1 is referred to as the central axis CA, and the direction parallel to the central axis CA is referred to as the "axial direction". In addition, one side of the axial direction from the lower bearing 8 toward the upper bearing 7 is referred to as the "upper axial direction", and the other side of the axial direction from the upper bearing 7 toward the lower bearing 8 is referred to as the "lower axial direction". Among the surfaces of each component, the surface facing the upper axial direction is referred to as the "upper surface", and the surface facing the lower axial direction is referred to as the "lower surface". In addition, in each component, the end in the axial direction is referred to as the "axial end", and the position of the end in the axial direction is referred to as the "axial end position". In particular, the end in the upper axial direction is referred to as the "upper axial end", and the position of the end in the upper axial direction is referred to as the "upper axial end position". Furthermore, the end in the lower axial direction is referred to as the "lower axial end", and the position of the end in the lower axial direction is referred to as the "lower axial end position".

[0022] In addition, the direction in which a straight line orthogonal to the central axis CA extends is referred to as the "radial direction". Further, one side of the radial direction toward the central axis CA is referred to as the "radial inner side", and the other side of the radial direction away from the central axis CA is referred to as the "radial outer side". Among the side surfaces of each component, the side surface facing the radial direction is referred to as the "radial side surface". In particular, the side surface facing the radial inner side is referred to as the "radial inner side surface", and the side surface facing the radial outer side is referred to as the "radial outer side surface". In addition, in each component, the end portion in the radial direction is referred to as the "radial end portion", and the position of the end portion in the radial direction is referred to as the "radial end". In particular, the end portion on the radial inner side is referred to as the "radial inner end portion", and the position of the end portion on the radial inner side is referred to as the "radial inner end". Furthermore, the end portion on the radial outer side is referred to as the "radial outer end portion", and the position of the end portion on the radial outer side is referred to as the "radial outer end".

[0023] In addition, the rotation direction centered on the central axis CA is referred to as the "circumferential direction". Further, the orientation counterclockwise with respect to the central axis CA when viewed from above the axial direction in the circumferential direction is referred to as the "one side of the circumferential direction", and the orientation clockwise with respect to the central axis CA when viewed from above the axial direction is referred to as the "other side of the circumferential direction". Among the side surfaces of each component, the side surface facing the circumferential direction is referred to as the "circumferential side surface". In addition, in each component, the end portion in the circumferential direction is referred to as the "circumferential end portion", and the position of the end portion in the circumferential direction is referred to as the "circumferential end". In particular, the end portion on the one side of the circumferential direction is referred to as the "end portion on the one side of the circumferential direction", and the position of the end portion on the one side of the circumferential direction is referred to as the "end portion on the one side of the circumferential direction". Furthermore, the end portion on the other side of the circumferential direction is referred to as the "end portion on the other side of the circumferential direction", and the position of the end portion on the other side of the circumferential direction is referred to as the "other end of the circumferential direction".

[0024] In addition, the names of the directions, surfaces, end portions, and their positions described above do not represent the positional relationship and directions when assembled into an actual device. Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings.

[0025] <Embodiment>

[0026] The motor 1 is a brushless motor that uses a three-phase alternating current composed of U-phase, V-phase, and W-phase as the drive current. The motor 1 according to the present embodiment is a so-called outer-rotor type motor in which the rotor rotates outside the stator.

[0027] In addition, the motor 1 described below can be applied to all devices as long as it is a device to which a motor can be applied.

[0028] Figure 1 is a cross-sectional view schematically showing the motor 1 according to the embodiment. As Figure 1 shown, the motor 1 includes a shaft 2, a rotor 3, a stator 4, a bracket 10 (stator holding portion), and a circuit board 5.

[0029] The shaft 2 is a rod-shaped member extending axially along the central axis CA and can rotate together with the rotor 3 about the central axis CA. That is, the shaft 2 is the rotating shaft of the motor 1. The shaft 2 is rotatably supported relative to the bracket 10 by the upper bearing 7 and the lower bearing 8. In the present embodiment, the upper bearing 7 and the lower bearing 8 are ball bearings, but are not limited thereto, and other types of bearings may also be used.

[0030] The rotor 3 is arranged to cover the radially outer side of the stator 4 and can rotate about the central axis CA extending axially. The rotor 3 is fixed to the shaft 2 by means of screw fixation or the like. As Figure 1 shown, the rotor 3 has an upper wall portion 31, a peripheral wall portion 35, and a plurality of magnets 38.

[0031] The upper wall portion 31 is a portion that is formed in a substantially circular shape when viewed from above in the axial direction. A through hole 31a is formed in the central portion of the upper wall portion 31, and the shaft 2 is fixed in the through hole 31a in an inserted state.

[0032] The peripheral wall portion 35 is formed in a cylindrical shape extending downward from the outer peripheral edge portion of the upper wall portion 31. The peripheral wall portion 35 is formed of a ferromagnetic material, for example. In addition, in Figure 1 it, an example is shown in which the upper wall portion 31 and the peripheral wall portion 35 are integrally formed of a single member, but is not limited thereto, and the upper wall portion 31 and the peripheral wall portion 35 may also be formed of different members and fixed to each other by an adhesive or the like.

[0033] The plurality of magnets 38 are formed in a substantially rectangular parallelepiped shape with a predetermined thickness. The plurality of magnets 38 are arranged in a substantially cylindrical shape along the circumferential direction. The plurality of magnets 38 are fixed to the inner circumferential surface of the peripheral wall portion 35 in such a manner that different magnetic poles (i.e., S pole, N pole) face radially inward alternately in the circumferential direction. For example, the magnets 38 are fixed to the peripheral wall portion 35 by an adhesive.

[0034] The stator 4 is provided inside the rotor 3. More specifically, the stator 4 is provided radially inward of the portion surrounded by the plurality of magnets 38 fixed to the rotor 3. The stator 4 has a stator core 41 and a plurality of coil portions 45.

[0035] The stator core 41 is disposed radially inside the rotor 3. In the present embodiment, the stator core 41 is formed by laminating electromagnetic steel sheets having a thickness in the axial direction in the axial direction. The stator core 41 has an annular core back 42 and a plurality of teeth 43 protruding radially outward from the outer peripheral surface of the core back 42. The plurality of teeth 43 are arranged at equal intervals in the circumferential direction.

[0036] A plurality of coil portions 45 are arranged along the circumferential direction. The plurality of coil portions 45 are formed by winding coil wires around respective teeth 43. The plurality of coil portions 45 are composed of a U-phase coil portion through which a U-phase current flows, a V-phase coil portion through which a V-phase current flows, and a W-phase coil portion through which a W-phase current flows (illustrations of all of them are omitted).

[0037] In the motor 1 according to the present embodiment, the rotor 3 rotates by a rotating magnetic field which is generated by the currents of U-phase, V-phase, and W-phase flowing through respective coil portions 35 via a power cable portion 9 connected to a circuit board 5.

[0038] The bracket 10 is a portion for holding the stator 4 of the motor 1. The bracket 10 has a cylindrical portion 11, a base portion 12, an outer wall portion 13, and a fastened portion 14, which are integrally formed from a single component. The bracket 10 is formed of a metal component (e.g., magnesium alloy).

[0039] The cylindrical portion 11 is a cylindrical wall portion arranged such that its central axis is coaxial with the central axis CA. The outer peripheral surface of the cylindrical portion 11 is in contact with the inner peripheral surface of the stator 4. The outer ring of the upper bearing 7 is held at the upper axial portion of the inner peripheral surface of the cylindrical portion 11, and the outer ring of the lower bearing 8 is held at the lower axial portion of the inner peripheral surface of the cylindrical portion 11. Thereby, the shaft 2 to which the inner rings of the upper bearing 7 and the lower bearing 8 are fixed is rotatably held with respect to the cylindrical portion 11.

[0040] The base portion 12 is a plate-like portion formed to extend in a circular shape radially outward from the lower portion of the cylindrical portion 11 and having a thickness in the vertical direction. When viewed axially, the radially outer end portion of the base portion 12 is formed to overlap the radially outer end portion of the peripheral wall portion 35 of the rotor 3 over the entire circumference. In addition, a minute gap is formed axially between the upper end surface of the base portion 12 and the lower end portion of the peripheral wall portion 35 of the rotor 3. Thereby, it is possible to prevent the peripheral wall portion 35 from rubbing against the base portion 12 when the rotor 3 rotates. In addition, depending on the use of the motor 1, a sealing member or the like may be provided in this gap portion to improve the waterproof performance.

[0041] The outer wall portion 13 is a cylindrical portion formed to extend downward from the outer portion of the base portion 12. The circuit board 5 is housed inside the outer wall portion 13. In addition, in the present embodiment, the lower opening portion of the outer wall portion 13 is in an exposed state, but it is not limited thereto. Specifically, the opening portion may be covered with a disc-shaped cover (illustration omitted). Thereby, it is possible to prevent the circuit board 5 from being exposed to the outside.

[0042] The fastened portion 14 is a portion formed in a substantially cylindrical shape and is integrated with the base portion 12 and the outer wall portion 13. The upper end portion of the fastened portion 14 is integrated with the base portion 12, and the side surface is integrated with the outer wall portion 13. The lower end surface 15 of the fastened portion 14 is formed to be flat.

[0043] Figure 2 is a view observed from the A-A direction Figure 1 of the figure. The motor 1 according to the present embodiment includes a first fastening portion 14a and a second fastening portion 14b. That is, the motor 1 includes two fastening portions 14a and 14b.

[0044] In the present embodiment, the first fastening portion 14a and the second fastening portion 14b are provided so as to sandwich the power cable portion 9. Specifically, referring to Figure 2 , when the central axis CA is used as a reference point and a half-line extending in the extending direction of the power cable portion 9 is used as a reference line L, the first fastening portion 14a is provided at a position 30 degrees counterclockwise from the reference line L with the reference point as the center. The second fastening portion 14b is provided at a position 30 degrees clockwise from the reference line L with the reference point as the center.

[0045] Figure 3 is a top view of the circuit board 5. In addition, Figure 4 is a bottom view of the circuit board 5. The circuit board 5 is a plate-shaped member having a circular outer shape, and various components (not shown) are mounted on both the front surface and the back surface. The circuit board 5 is fixed to the fastening portion 14 of the bracket 10.

[0046] The circuit board 5 is housed inside the bracket 10. Specifically, the outer peripheral edge portion of the circuit board 5 is covered from the radially outer side by the inner peripheral surface of the outer wall portion of the bracket 10. Thereby, it is possible to prevent the circuit board 5 from being exposed to the outside of the motor 1.

[0047] A first cutout portion 5a and a second cutout portion 5b are formed in the outer peripheral edge portion of the circuit board 5. That is, two cutout portions are formed on the circuit board 5. Each of the cutout portions 5a and 5b is formed in a substantially semicircular arc shape when observed from the axial direction.

[0048] Referring to Figure 1 , when observed from the axial direction, the first cutout portion 5a is provided at a position overlapping the first fastening portion 14a. Similarly, although not shown, when observed from the axial direction, the second cutout portion 5b is provided at a position overlapping the second fastening portion 14b.

[0049] Referring to Figures 2 to 4, a frame grounding portion 51 is provided on the circuit board 5. In the motor 1, the circuit board 5 is fixed to the bracket 10 by fastening screws 6. Thus, as will be described in detail later, the frame grounding portion 51 is electrically connected to the bracket 10. As a result, the circuit board 5 housed inside the bracket 10 is in a state shielded by the bracket 10, so that electromagnetic noise generated from the electronic components mounted on the circuit board 5 can be prevented from leaking to the outside of the motor 1. The frame grounding portion 51 is electrically connected to a signal ground (not shown) via a prescribed electronic component (such as a resistor, a capacitor, etc.), for example.

[0050] The frame grounding portion 51 has an upper frame grounding surface 52 (first frame grounding surface) and a lower frame grounding surface 56 (second frame grounding surface). Refer to Figure 3 , the upper frame grounding surface 52 is a conductive pattern formed on the upper surface of the circuit board 5 and is formed on the surface opposite to the base portion 12. The lower frame grounding surface 56 is a conductive pattern formed on the lower surface of the circuit board 5 and is formed on the surface opposite to the surface where the upper frame grounding surface is formed. The upper frame grounding surface 52 and the lower frame grounding surface 56 are electrically connected by a through hole (not shown).

[0051] Refer to Figure 3 , the upper frame grounding surface 52 is formed in an annular shape at the outer peripheral portion of the upper surface of the circuit board 5. Specifically, the upper frame grounding surface 52 has arc portions 53 formed in an arc shape near the respective cutout portions 5a, 5b and connecting portions 54 connecting the respective arc portions to each other. The upper frame grounding surface 52 is formed of a conductive component such as copper and has a gold plating on its surface. The upper frame grounding surface 52 is not covered with a resist and is exposed to the outside.

[0052] Refer to Figure 4 , the lower frame grounding surface 56 is formed in an annular shape at the outer peripheral portion of the lower surface of the circuit board 5. Specifically, the lower frame grounding surface 56 has arc portions 57 formed in an arc shape near the respective cutout portions 5a, 5b and connecting portions 58 connecting the respective arc portions to each other. When viewed from the axial direction, the lower frame grounding surface 56 has a shape overlapping with the upper frame grounding surface 52. The lower frame grounding surface 56, like the upper frame grounding surface 52, is formed of a conductive component such as copper and has a gold plating on its surface. The lower frame grounding surface 56 is not covered with a resist and is exposed to the outside.

[0053] Figure 5 is Figure 1An enlarged view near the fastening screw 6 in [the figure] is a view showing the omission of the power cable portion 9. The fastening screw 6 is a component for fastening the circuit board 5 to the bracket 10. The motor 1 according to the present embodiment has a first fastening screw 6a and a second fastening screw 6b. That is, the motor 1 is provided with two fastening screws 6a and 6b. In addition, hereinafter, when explaining without distinguishing each fastening screw, 6 is used as the symbol of the fastening screw, and when explaining by distinguishing each fastening screw, 6a and 6b are used as the symbols of the fastening screws.

[0054] The fastening screw 6 has a head 61 and a screw body portion 65, which are integrally formed of a single component. The fastening screw 6 is, for example, a self-tapping screw. The fastening screw 6 is formed of a conductive component, such as iron or stainless steel.

[0055] The head 61 is a substantially cylindrical portion formed to have a thickness in the vertical direction. A threaded hole portion 62 for the fastening screw is formed on one side surface of the head 61. A screw body portion 65 extending in a direction away from this surface is integrally formed on the other side surface. In addition, the other side surface of the head 61, that is, the surface of the head 61 on the screw body portion 65 side, is formed as a flat surface 63 that is flat in the horizontal direction with respect to the extending direction of the screw body portion 65.

[0056] The screw body portion 65 is a portion having an outer shape smaller than the head 61 and longer in the axial direction, and a spiral thread portion 66 is formed on its outer peripheral surface. The screw body portion 65 is threadedly fixed to the fastened portion 14.

[0057] Refer to Figure 2 , when viewed from the axial direction, each fastening screw 6a, 6b is provided at a position overlapping with each fastened portion 14a, 14b. Specifically, when viewed from the axial direction, the first fastening screw 6a is provided at a position overlapping with the first fastened portion 14a, and the second fastening screw 6b is provided at a position overlapping with the second fastened portion 14b.

[0058] Each fastening screw 6a, 6b and the corresponding fastened parts 14a, 14b together fix the circuit board 5 relative to the bracket 10. Specifically, each fastening screw 6a, 6b is held in a state where the circuit board 5 is sandwiched between the head 61 and the fastened parts 14a, 14b with the screw main body part 65 threadedly fixed to the fastened parts 14a, 14b of the bracket 10. The fastening screws 6a, 6b are fastened and fixed to the respective fastened parts 14a, 14b in a state of being disposed inside the respective cutout parts 5a, 5b of the circuit board 5. That is, the fastening screw 6a and the fastened part 14a function as a first fixing mechanism 18 that sandwiches and holds the periphery of the cutout part 5a of the circuit board 5 in the vertical direction. In addition, the fastening screw 6b and the fastened part 14b function as a second fixing mechanism 19 that sandwiches and holds the periphery of the cutout part 5b of the circuit board 5 in the vertical direction. That is, through these fixing mechanisms 18, 19, the circuit board 5 is fixed to the bracket 10.

[0059] In this state, referring to Figure 5 , the flat surface 63 of the head 61 of the fastening screw 6a is in surface contact with the arc part 57 of the lower side frame grounding surface 56. Thereby, it is possible to bring the two into contact with each other over a wide range, so that the frame grounding can be made electrically stable. Similarly, although not shown in the figure, the flat surface 63 of the head 61 of the fastening screw 6b is also in surface contact with the arc part 57 of the lower side frame grounding surface 56.

[0060] In addition, in this state, the arc part 53 of the upper side frame grounding surface 52 is in surface contact with the lower end surface 15 of the fastened part 14a. Thereby, it is possible to bring the two into contact with each other over a wide range, so that the frame grounding can be made electrically stable. Similarly, although not shown in the figure, the arc part 53 of the upper side frame grounding surface 52 is in surface contact with the lower end surface 15 of the fastened part 14b. That is, the fastening screws 6a, 6b are in contact with both the frame grounding part 51 of the circuit board 5 and the bracket 10.

[0061] In addition, in this state, referring to Figure 2 , when viewed from the axial direction, the first fixing mechanism 18 is provided on the counterclockwise side with respect to the power cable part 9 centered on the central axis CA, and when viewed from the axial direction, the second fixing mechanism 19 is provided on the clockwise side with respect to the power cable part 9 centered on the central axis CA. That is, the power cable part 9 is provided between the two fixing mechanisms 18, 19. Thereby, even if, for example, a downward force is applied to the power cable part 9, deformation of the circuit board 5 can be suppressed by the two fixing mechanisms 18, 19.

[0062] <Effect>

[0063] As described above, in the present embodiment, the circuit board 5 is fixed to the bracket 10 by the fastening screw 6. Thereby, the circuit board 5 can be firmly fixed relative to the bracket 10. That is, according to the present embodiment, a motor with excellent durability can be provided without performing complex operations.

[0064] In addition, in the present embodiment, the frame grounding portion 51 can be electrically connected to the bracket 10 in a state where the circuit board 5 is fixed to the fastened portion 14 of the bracket 10 by the conductive fastening screw 6. Thus, each electronic component mounted on the circuit board 5 is shielded in a state of being covered by the outer wall portion 13 of the bracket 10, so that electromagnetic noise generated from the circuit board 5 can be suppressed from leaking to the outside of the bracket 10.

[0065] Moreover, in the present embodiment, the fixing of the circuit board 5 relative to the bracket 10 and the frame grounding for preventing electromagnetic noise from the circuit board 5 from leaking to the outside are achieved by using the screw fixing of the fastening screw 6. That is, according to the present embodiment, by such an easy method as screw fixing, both the fixing of the circuit board and the prevention of the leakage of electromagnetic noise can be achieved simultaneously.

[0066] In addition, in the present embodiment, the circuit board 5 can be fixed relative to the bracket 10 by the fixing mechanisms 18, 19 constituted by the fastened portion 14 integrally provided with at least one of the base portion 12 and the outer wall portion 13 and the fastening screw 6.

[0067] <2. Modified Example>

[0068] In the above-described embodiment, a motor having two fixing mechanisms 18, 19 is described as an example, but it is not limited thereto. The fixing mechanism may be one, or may be three or more.

[0069] In addition, in the above-described embodiment, a structure in which the upper frame ground surface 52 and the lower frame ground surface 56 are provided as the frame grounding portion 51, the upper frame ground surface 52 is in contact with the bracket 10, and the lower frame ground surface 56 is in contact with the fastening screw 6 is adopted, but it is not limited thereto. Specifically, as long as it is a structure in which the fastening screw 6 is in contact with the frame grounding portion 51 and the bracket 10, any structure may be used. For example, a structure in which the upper frame ground surface 52 is omitted in the above-described embodiment may also be used.

[0070] <3. Others>

[0071] The above has described the embodiments of the present invention. In addition, the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented by making various changes to the above-described embodiments within the scope not departing from the gist of the invention. In addition, the matters described in the above-described embodiments can be appropriately and arbitrarily combined within a range not causing contradictions.

[0072] <4. Summary>

[0073] Hereinafter, the embodiments described so far will be summarized.

[0074] The motor is configured as follows (first configuration), and includes:

[0075] A stator having a plurality of coil portions arranged along the circumferential direction;

[0076] A rotor provided so as to cover the radially outer side of the stator and rotatable about a central axis extending in the axial direction;

[0077] A conductive stator holding portion having a cylindrical portion, a base portion, and an outer wall portion. The cylindrical portion has an outer peripheral surface that contacts the inner peripheral surface of the stator. The base portion extends radially outward from a lower portion of the cylindrical portion. The outer wall portion extends downward from an outer portion of the base portion;

[0078] A circuit board fixed relative to the stator holding portion; and

[0079] A conductive fastening screw having a head and a screw body portion. In a state where the screw body portion is threadedly fixed to the stator holding portion, it is held in a state where the circuit board is sandwiched between the head and the stator holding portion, and contacts both the frame ground portion of the circuit board and the stator holding portion.

[0080] Further, in the motor of the first configuration, the outer peripheral edge portion of the circuit board may be covered by the outer wall portion (second configuration).

[0081] Further, in the motor of the first or second configuration, the stator holding portion may further include a portion to be fastened, which is integrally provided with at least one of the base portion and the outer wall portion and threadedly fixes the screw body portion. By the fixing mechanism having the fastening screw and the portion to be fastened, the circuit board is fixed to the stator holding portion (third configuration).

[0082] Further, in the motor of any one of the first to third configurations, the frame ground portion may have a first frame ground surface formed on a surface of the circuit board opposite to the base portion, and the first frame ground surface contacts the portion to be fastened (fourth configuration).

[0083] Further, in the motor having any one of the first to fourth structures, the frame grounding portion may also have a second frame grounding surface formed on the surface of the circuit board opposite to the surface facing the base portion, and the surface of the head on the side of the screw main body portion is formed as a flat surface, and the flat surface is in contact with the second frame grounding surface (fifth structure).

[0084] Further, in any one of the motors having the third structure, the fourth structure including the third structure, and the fifth structure including the third structure, a plurality of the fixing mechanisms including at least a first fixing mechanism and a second fixing mechanism may be provided. When viewed from the axial direction, the first fixing mechanism is provided on the counterclockwise side of the power cable portion with the central axis as the center, and when viewed from the axial direction, the second fixing mechanism is provided on the clockwise side of the power cable portion with the central axis as the center (sixth structure).

[0085] Industrial applicability

[0086] The present invention is useful for a motor having a circuit board.

Claims

1. A motor, characterized in that, Comprising: A stator having a plurality of coil portions arranged circumferentially; A rotor provided so as to cover the radially outer side of the stator and capable of rotating about a central axis extending in the axial direction; A conductive stator holding portion having a cylindrical portion, a base portion, and an outer wall portion, the cylindrical portion having an outer peripheral surface in contact with the inner peripheral surface of the stator, the base portion extending radially outward from a lower portion of the cylindrical portion, and the outer wall portion extending downward from an outer portion of the base portion; A circuit board fixed relative to the stator holding portion; and A conductive fastening screw having a head and a screw body portion, and in a state where the screw body portion is screwed and fixed to the stator holding portion, holding the circuit board in a state where the circuit board is sandwiched between the head and the stator holding portion, and contacting both the frame ground portion of the circuit board and the stator holding portion.

2. The motor according to claim 1, wherein: The outer peripheral edge portion of the circuit board is covered by the outer wall portion.

3. The motor according to claim 1, wherein: The stator holding portion further includes a portion to be fastened, the portion to be fastened being integrally provided with at least one of the base portion and the outer wall portion and threadedly fixing the screw body portion, By a fixing mechanism having the fastening screw and the portion to be fastened, the circuit board is fixed to the stator holding portion.

4. The motor according to claim 3, wherein: The frame ground portion has a first frame ground surface formed on a surface of the circuit board opposite to the base portion, The first frame ground surface contacts the portion to be fastened.

5. The motor according to claim 3, wherein: The frame ground portion further has a second frame ground surface formed on a surface opposite to the surface of the circuit board opposite to the base portion, The surface of the head on the screw body portion side is a flat surface formed to be flat, The flat surface contacts the second frame ground surface.

6. The motor according to any one of claims 3 to 5, wherein: There are provided a plurality of the fixing mechanisms including at least a first fixing mechanism and a second fixing mechanism, When viewed from the axial direction, the first fixing mechanism is provided on the counterclockwise side of the power cable portion with the central axis as the center, When viewed from the axial direction, the second fixing mechanism is provided on the clockwise side of the power cable portion with the central axis as the center.

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