Motor

Abstract

To provide a durable motor without the need for complicated work.SOLUTION: A motor 1 includes a stator 4, a rotor 3, a conductive stator holding portion 10 that holds the stator 4, a circuit board 5, and a fastening screw 6, and the conductive fastening screw 6 has a head and a screw body, and when the screw body is screwed into the stator holding portion 10, it holds the circuit board 5 sandwiched between the head and the stator holding portion 10, and is in contact with both a frame ground portion of the circuit board 5 and the stator holding portion 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when connecting a circuit board to a stationary part of a motor using connection pins as shown in Patent Document 1, the connection strength may be insufficient. In contrast, it is conceivable to solder the connection pins to the circuit board to enhance the fixing strength, but the working process becomes complicated.

[0005] 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 work.

Means for Solving the Problems

[0006] An exemplary motor of the present invention includes a stator having a plurality of coil portions arranged along the circumferential direction, 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, a cylindrical portion having an outer peripheral surface that contacts the inner peripheral surface of the stator, a base portion that extends radially outward from the lower portion of the cylindrical portion, and an outer wall portion that extends downward from the outer portion of the base portion. A conductive stator holding portion having, a circuit board fixed to the stator holding portion, a head and a screw body portion, and when the screw body portion is screwed to the stator holding portion, the circuit board is sandwiched between the head and the stator holding portion and held, and a conductive fastening screw that contacts both the frame ground portion of the circuit board and the stator holding portion.

Advantages of the Invention

[0007] According to the present invention, a motor with excellent durability can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Exemplary embodiments of the present invention will be described below with reference to the drawings.

[0010] 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". Also, one of the axial directions from the lower bearing 8 toward the upper bearing 7 is referred to as the "upper axial direction", and the other axial direction from the upper bearing 7 toward the lower bearing 8 is referred to as the "lower axial direction". On the surface of each component, the surface facing upward in the axial direction is referred to as the "upper surface", and the surface facing downward in the axial direction is referred to as the "lower surface". Also, in each component, the end portion in the axial direction is referred to as the "axial end portion", and the position of the end portion in the axial direction is referred to as the "axial end". In particular, the end portion in the upper axial direction is referred to as the "upper axial end portion", and the position of the end portion in the upper axial direction is referred to as the "upper axial end". Further, the end portion in the lower axial direction is referred to as the "lower axial end portion", and the position of the end portion in the lower axial direction is referred to as the "lower axial end".

[0011] Also, the direction in which a straight line orthogonal to the central axis CA extends is referred to as the "radial direction". Also, one of the radial directions toward the central axis CA is referred to as the "radial inner direction", and the other radial direction away from the central axis CA is referred to as the "radial outer direction". On the side surface 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 direction is referred to as the "radial inner side surface", and the side surface facing the radial outer direction is referred to as the "radial outer side surface". Also, 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 in the radial inner direction is referred to as the "radial inner end portion", and the position of the end portion in the radial inner direction is referred to as the "radial inner end". Further, the end portion in the radial outer direction is referred to as the "radial outer end portion", and the position of the end portion in the radial outer direction is referred to as the "radial outer end".

[0012] Also, the rotational direction centered on the central axis CA is referred to as the "circumferential direction". Among the circumferential directions, the counterclockwise direction with respect to the central axis CA as viewed from above in the axial direction is referred to as the "one side of the circumferential direction", and the clockwise direction with respect to the central axis CA as viewed from above in the axial direction is referred to as the "other side of the circumferential direction". On the side surface of each component, the side surface facing the circumferential direction is referred to as the "circumferential side surface". Also, 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 one side of the circumferential direction is referred to as the "one end portion of the circumferential direction", and the position of the end portion on one side of the circumferential direction is referred to as the "one end of the circumferential direction". Furthermore, the end portion on the other side of the circumferential direction is referred to as the "other end portion 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".

[0013] Note that the names of the directions, surfaces, end portions, and their positions described above do not indicate the positional relationship and direction when incorporated into an actual device. Exemplary embodiments will be described below with reference to the drawings.

[0014] <Embodiment> 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.

[0015] Note that the motor 1 described below is applicable to any device as long as it is a device to which the motor can be applied.

[0016] FIG. 1 is a cross-sectional view schematically showing the motor 1 according to the embodiment. As shown in FIG. 1, the motor 1 includes a shaft 2, a rotor 3, a stator 4, a bracket 10 (stator holding portion), and a circuit board 5.

[0017] The shaft 2 is a round bar-shaped member extending axially along the central axis CA, and is rotatable together with the rotor 3 about the central axis CA. That is, the shaft 2 is the rotation axis of the motor 1. The shaft 2 is rotatably supported with respect 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 the present invention is not limited thereto, and other types of bearings may be used.

[0018] The rotor 3 is provided so as to cover the radially outer side of the stator 4 and is rotatable about the central axis CA extending in the axial direction. The rotor 3 is fixed to the shaft 2 by screwing or the like. As shown in FIG. 1, the rotor 3 has an upper wall portion 31, a peripheral wall portion 35, and a plurality of magnets 38.

[0019] The upper wall portion 31 is a portion 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 a state of being inserted into the through hole 31a.

[0020] 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, for example, a ferromagnetic material. In FIG. 1, an example in which the upper wall portion 31 and the peripheral wall portion 35 are integrally formed as a single member is shown, but the present invention is not limited thereto, and the upper wall portion 31 and the peripheral wall portion 35 may be formed of separate members and fixed to each other by an adhesive or the like.

[0021] The plurality of magnets 38 are formed in a substantially rectangular parallelepiped shape having 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 peripheral surface of the peripheral wall portion 35 such that different magnetic poles (that is, S pole, N pole) face radially inward alternately in the circumferential direction. For example, the magnet 38 is fixed to the peripheral wall portion 35 by an adhesive.

[0022] The stator 4 is provided inside the rotor 3. More specifically, the stator 4 is provided radially inward of the portion surrounded by a plurality of magnets 38 fixed to the rotor 3. The stator 4 includes a stator core 41 and a plurality of coil portions 45.

[0023] The stator core 41 is disposed radially inward of the rotor 3. In the present embodiment, the stator core 41 is configured 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.

[0024] The plurality of coil portions 45 are arranged along the circumferential direction. The plurality of coil portions 45 are formed by winding coil wires around the respective teeth 43. The plurality of coil portions 45 include 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 (all not shown).

[0025] In the motor 1 according to the present embodiment, the rotor 3 rotates due to a rotating magnetic field generated by the flow of U-phase, V-phase, and W-phase currents through the respective coil portions 35 via the power cable portion 9 connected to the circuit board 5.

[0026] The bracket 10 is a portion that holds the stator 4 in 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, and these are integrally formed by a single member. The bracket 10 is formed of a metal member (for example, a magnesium alloy).

[0027] 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 portion in the axial direction on the inner peripheral surface of the cylindrical portion 11, and the outer ring of the lower bearing 8 is held at the lower portion in the axial direction on the inner peripheral surface of the cylindrical portion 11. Thereby, the shaft 2 with the inner ring of the upper bearing 7 and the inner ring of the lower bearing 8 fixed is rotatably held with respect to the cylindrical portion 11.

[0028] The base portion 12 is a plate-like portion having a thickness in the vertical direction, formed to extend annularly radially outward from the lower portion of the cylindrical portion 11. The radially outer end portion of the base portion 12 is formed so as to overlap the radially outer end portion of the peripheral wall portion 35 of the rotor 3 over the entire circumference when viewed from the axial direction. Also, a slight gap is formed in the axial direction 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 during the rotation of the rotor 3. Depending on the use of the motor 1, a sealing member or the like can be provided in this gap portion to improve the waterproof performance.

[0029] The outer wall portion 13 is a cylindrical portion formed to extend downward from the outer portion of the base portion 12. A circuit board 5 is housed inside the outer wall portion 13. In the present embodiment, the lower opening portion of the outer wall portion 13 is in an exposed state, but this is not the case in all situations. Specifically, the opening portion may be covered by a disc-shaped cover (not shown). Thereby, it is possible to prevent the circuit board 5 from being exposed to the outside.

[0030] 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 in a flat shape.

[0031] Figure 2 is a view of FIG. 1 seen from the A-A direction. The motor 1 according to the present embodiment includes a first fastened portion 14a and a second fastened portion 14b. That is, the motor 1 includes two fastened portions 14a and 14b.

[0032] In the present embodiment, the first fastened portion 14a and the second fastened portion 14b are provided so as to sandwich the power cable portion 9. Specifically, referring to FIG. 2, when the first fastened portion 14a has a reference line L which is a half line extending in the direction in which the power cable portion 9 extends with the central axis CA as a reference point, the first fastened portion 14a is provided at a position 30 degrees counterclockwise from the reference line L around the reference point. The second fastened portion 14b is provided at a position 30 degrees clockwise from the reference line L around the reference point.

[0033] Figure 3 is a plan view of the circuit board 5. FIG. 4 is a bottom view of the circuit board 5. The circuit board 5 is a plate-like 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 fastened portion 14 of the bracket 10.

[0034] 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.

[0035] A first notch portion 5a and a second notch portion 5b are formed in the outer peripheral edge portion of the circuit board 5. That is, two notch portions are formed in the circuit board 5. Each of the notch portions 5a and 5b is formed to have a substantially semi-circular arc shape when viewed from the axial direction.

[0036] Referring to FIG. 1, the first notch portion 5a is provided at a position overlapping the first fastened portion 14a when viewed from the axial direction. Similarly, although not shown, the second notch portion 5b is provided at a position overlapping the second fastened portion 14b when viewed from the axial direction.

[0037] As shown in FIGS. 2 to 4, a frame ground 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, and thus the frame ground portion 51 is electrically connected to the bracket 10 as will be described in detail later. As a result, the circuit board 5 housed inside the bracket 10 is shielded by the bracket 10, and thus it is possible to prevent electromagnetic noise generated from the electronic components mounted on the circuit board 5 from leaking to the outside of the motor 1. The frame ground portion 51 is electrically connected to, for example, a signal ground (not shown) via predetermined electronic components (resistors, capacitors, etc.).

[0038] The frame ground portion 51 has an upper frame ground surface 52 (first frame ground surface) and a lower surface frame ground surface 56 (second frame ground surface). Referring to FIG. 3, the upper frame ground surface 52 is a conductive pattern formed on the upper surface of the circuit board 5 and is formed on the surface facing the base portion 12. The lower frame ground 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 on which the upper frame ground surface is formed. The upper frame ground surface 52 and the lower frame ground surface 56 are electrically connected by through holes (not shown).

[0039] Referring to FIG. 3, the upper frame ground surface 52 is formed in an annular shape on the outer peripheral portion of the upper surface of the circuit board 5. Specifically, the upper frame ground surface 52 has arc portions 53 formed in an arc shape near the respective notch portions 5a and 5b, and connecting portions 54 connecting the respective arc portions. The upper frame ground surface 52 is formed of a conductive member such as copper, and its surface is gold-plated. The upper frame ground surface 52 is not covered with a resist and is exposed to the outside.

[0040] The lower frame ground surface 56 is formed in an annular shape on the outer peripheral portion of the lower surface of the circuit board 5 with reference to FIG. 4. Specifically, the lower frame ground surface 56 has an arc portion 57 formed in an arc shape near each notch portion 5a, 5b, and a connecting portion 58 connecting the arc portions to each other. The lower frame ground surface 56 has a shape that overlaps with the upper frame ground surface 52 when viewed from the axial direction. The lower frame ground surface 56 is formed of a conductive member such as copper, and its surface is gold-plated, similar to the upper frame ground surface 52. The lower frame ground surface 56 is not covered with a resist and is exposed to the outside.

[0041] FIG. 5 is an enlarged view of the vicinity of the fastening screw 6 in FIG. 1, showing the power cable portion 9 omitted. The fastening screw 6 is a member 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, 6b. Hereinafter, when explaining without distinguishing each fastening screw, 6 is used as the reference numeral of the fastening screw, and when explaining by distinguishing each fastening screw, 6a and 6b are used as the reference numerals of the fastening screws.

[0042] The fastening screw 6 has a head portion 61 and a screw body portion 65, and these are integrally formed by a single member. The fastening screw 6 is, for example, a self-tapping screw. The fastening screw 6 is formed of a conductive member such as iron or stainless steel.

[0043] The head portion 61 is a portion formed in a substantially cylindrical shape having a thickness in the vertical direction. A screw hole portion 62 for fastening the screw is formed on one surface of the head portion 61. On the other surface, a screw body portion 65 extending in a direction away from the surface is integrally formed. Also, the other surface of the head portion 61, that is, the surface of the head portion 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 direction in which the screw body portion 65 extends.

[0044] The screw main body portion 65 is a portion that is smaller in outer shape and longer in the axial direction than the head portion 61, and a spiral thread portion 66 is formed on its outer peripheral surface. The screw main body portion 65 is screwed to the fastened portion 14.

[0045] As shown in FIG. 2, each fastening screw 6a, 6b is provided at a position overlapping with each fastened portion 14a, 14b when viewed from the axial direction. 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.

[0046] Each fastening screw 6a, 6b, together with each corresponding fastened portion 14a, 14b, fixes the circuit board 5 to the bracket 10. Specifically, in a state where the screw main body portion 65 is screwed to the fastened portions 14a, 14b of the bracket 10, each fastening screw 6a, 6b holds the circuit board 5 in a state of sandwiching it between the head portion 61 and the fastened portions 14a, 14b. The fastening screws 6a, 6b are fastened and fixed to the respective fastened portions 14a, 14b while being disposed inside the respective notch portions 5a, 5b in the circuit board 5. That is, the fastening screw 6a and the fastened portion 14a function as a first fixing mechanism 18 that sandwiches and holds a portion around the notch portion 5a in the circuit board 5 in the vertical direction. Also, the fastening screw 6b and the fastened portion 14b function as a second fixing mechanism 19 that sandwiches and holds a portion around the notch portion 5b in the circuit board 5 in the vertical direction. That is, the circuit board 5 is fixed to the bracket 10 by these fixing mechanisms 18, 19.

[0047] In this state, referring to FIG. 5, the flat surface 63 of the head portion 61 of the fastening screw 6a is in surface contact with the arc portion 57 of the lower frame ground surface 56. Thereby, since the two can be brought into contact over a wide range, the frame ground can be electrically stabilized. Similarly, although not shown, the flat surface 63 of the head portion 61 of the fastening screw 6b is also in surface contact with the arc portion 57 of the lower frame ground surface 56.

[0048] Also in this state, the arc portion 53 of the upper frame ground surface 52 is in surface contact with the lower end surface 15 of the fastened portion 14a. As a result, since the two can be brought into contact over a wide range, the frame ground can be electrically stabilized. Similarly, although not shown, the arc portion 53 of the upper frame ground surface 52 is in surface contact with the lower end surface 15 of the fastened portion 14b. That is, the fastening screws 6a and 6b are in contact with both the frame ground portion 51 of the circuit board 5 and the bracket 10.

[0049] Also in this state, with reference to FIG. 2, the first fixing mechanism 18 is provided on the counterclockwise side of the power cable portion 9 about the central axis CA when viewed from the axial direction, and the second fixing mechanism 19 is provided on the clockwise side of the power cable portion 9 about the central axis CA when viewed from the axial direction. That is, the power cable portion 9 is provided between the two fixing mechanisms 18 and 19. Thereby, for example, even if a downward force is applied to the power cable portion 9, deformation of the circuit board 5 can be suppressed by the two fixing mechanisms 18 and 19.

[0050] <Effect> 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 to the bracket 10. That is, according to the present embodiment, a motor excellent in durability can be provided without performing complicated work.

[0051] Also, in the present embodiment, 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, the frame ground portion 51 can be electrically connected to the bracket 10. As a result, since 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, it is possible to suppress electromagnetic noise generated from the circuit board 5 from leaking to the outside of the bracket 10.

[0052] In this embodiment, the fixing of the circuit board 5 to the bracket 10 and the frame ground for preventing electromagnetic noise from leaking from the circuit board 5 to the outside are realized by screwing with the fastening screw 6. That is, according to this embodiment, by an easy method of screwing, both the fixing of the circuit board and the prevention of electromagnetic noise leakage can be realized simultaneously.

[0053] Also, in this embodiment, the circuit board 5 can be fixed to the bracket 10 by fixing mechanisms 18, 19 constituted by a fastened portion 14 provided integrally with at least one of the base portion 12 and the outer wall portion 13 and the fastening screw 6.

[0054] <2. Modification Example> In the above embodiment, a motor having two fixing mechanisms 18, 19 has been described as an example. However, this is not the limit, and the number of fixing mechanisms may be one, or may be three or more.

[0055] Also, in the above embodiment, the upper frame ground surface 52 and the lower frame ground surface 56 are provided as the frame ground portion 51, and the upper frame ground surface 52 is brought into contact with the bracket 10, and the lower frame ground surface 56 is brought into contact with the fastening screw 6. However, the present invention is not limited to this. Specifically, any configuration may be adopted as long as the fastening screw 6 is configured to be in contact with the frame ground portion 51 and the bracket 10. For example, in the above-described embodiment, a configuration in which the upper frame ground surface 52 is omitted may be adopted.

[0056] <3. Others> The embodiments of the present invention have been described above. Note that the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented with various modifications to the above-described embodiments without departing from the gist of the invention. Also, the matters described in the above-described embodiments can be arbitrarily combined as appropriate without causing contradictions.

[0057] <4. Summary> Hereinafter, the embodiments described so far will be summarized.

[0058] The motor includes a stator having a plurality of coil portions arranged along the circumferential direction, a rotor provided to cover the radially outer side of the stator and rotatable about a central axis extending in the axial direction, a conductive stator holder having a cylindrical portion having an outer peripheral surface that contacts the inner peripheral surface of the stator, a base portion that extends radially outward from a lower portion of the cylindrical portion, and an outer wall portion that extends downward from an outer portion of the base portion, a circuit board fixed to the stator holder, a fastening screw having a head and a screw body portion, and in a state where the screw body portion is screwed to the stator holder, holding the circuit board sandwiched between the head and the stator holder, and being conductive and contacting both the frame ground portion of the circuit board and the stator holder, and is configured as a first configuration.

[0059] 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).

[0060] In the motor of the first or second configuration, the stator holder may be provided integrally with at least one of the base portion and the outer wall portion, further include a fastened portion to which the screw body portion is screwed, and the circuit board may be fixed to the stator holder by a fixing mechanism having the fastening screw and the fastened portion (third configuration).

[0061] In the motor of any one of the first to third configurations, the frame ground portion has a first frame ground surface formed on a surface of the circuit board facing the base portion, and the first frame ground surface may be in contact with the fastened portion (fourth configuration).

[0062] In addition, in the motor having any one of the first to fourth configurations, the frame ground portion further has a second frame ground surface formed on a surface opposite to the surface of the circuit board facing the base portion, the surface of the head on the side of the screw body portion is a flat surface formed in a flat shape, and the flat surface and the second frame ground surface may be in contact with each other (fifth configuration).

[0063] In addition, in any one of the motor having the third configuration, the motor having the fourth configuration including the third configuration, and the motor having the fifth configuration including the third configuration, a plurality of the fixing mechanisms including at least the first fixing mechanism and the second fixing mechanism are provided. The first fixing mechanism is provided on the counterclockwise side of the power cable portion around the central axis when viewed from the axial direction, and the second fixing mechanism may be provided on the clockwise side of the power cable portion around the central axis when viewed from the axial direction (sixth configuration).

Industrial Applicability

[0064] The present invention is useful for a motor provided with a circuit board.

Explanation of Reference Numerals

[0065] 1... Motor, 2... Shaft, 3... Rotor, 4... Stator, 5... Circuit board, 6... Fastening screw, 10... Bracket (stator holding portion), 11... Cylindrical portion, 12... Base portion, 13... Outer wall portion, 45... Coil portion, 51... Frame ground portion, 61... Head, 62... Screw body portion, CA... Central axis

Claims

1. A stator having a plurality of coil portions arranged along the circumferential direction, 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, a conductive stator holding portion having a cylindrical portion having an outer peripheral surface in contact with the inner peripheral surface of the stator, a base portion extending radially outward from a lower portion of the cylindrical portion, and an outer wall portion extending downward from an outer portion of the base portion, a circuit board fixed to the stator holding portion, a fastening screw having a head and a screw main body portion, the screw main body portion being screwed to the stator holding portion and holding the circuit board sandwiched between the head and the stator holding portion, and the fastening screw being conductive and contacting both the frame ground portion of the circuit board and the stator holding portion, A motor, characterized by comprising the above.

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

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

4. The frame ground portion has a first frame ground surface formed on a surface of the circuit board on a side facing the base portion, The motor according to claim 3, wherein the first frame ground surface is in contact with the fastened portion.

5. The frame ground portion further has a second frame ground surface formed on a surface of the circuit board opposite to the surface on the side facing the base portion, A surface of the head on the side of the screw main body portion is a flat surface formed in a flat shape, The motor according to claim 3, wherein the flat surface is in contact with the second frame ground surface.

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

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