Electric motor

Abstract

This motor is provided with: a rotor having a rotating shaft extending in the axial direction; a commutator attached to the rotating shaft; a brush in contact with the commutator; and a brush spring for pressing the brush against the commutator, the brush spring having: a first wrap portion and a second wrap portion, each of the first wrap portion and the second wrap portion comprising a strip-shaped plate material wound in a spiral shape; and a connecting portion that connects the belt-shaped wire constituting the first wrap and the belt-shaped wire constituting the second wrap, the brush being pressed against the commutator by a load from the connecting portion.

Description

Technical Field

[0001] The present disclosure relates to electric motors. Background Art

[0002] Electric motors are widely used in the field of household electrical appliances such as electric vacuum cleaners, and also in the field of electrical equipment such as automobiles. For example, an electric blower mounted on an electric vacuum cleaner uses an electric motor to rotate a rotary fan. Two-wheeled or four-wheeled vehicles use electric motors to drive cooling fans such as radiators.

[0003] As electric motors, there are known brushed motors (commutator motors) using brushes and brushless motors not using brushes. Among them, the brushed motor includes: a stator; a rotor that rotates under the action of the magnetic force of the stator; a commutator that is attached to the rotating shaft of the rotor; and a brush that is in sliding contact with the commutator.

[0004] In a brush motor, a brush spring is used to press the brush against the commutator. The brush spring presses the brush by utilizing spring elasticity. Conventionally, a coil spring or a torsion spring has been used as a brush spring for a brush motor.

[0005] However, in the case of a coil spring or a torsion spring, the difference between the pressure before the brush wears (initial pressure) and the pressure when the motor reaches the end of its life due to the wear of the brush (final pressure) is large. Therefore, in the case of a coil spring or a torsion spring, in order to ensure a final pressure above a certain level, the initial pressure needs to be set higher. Therefore, in the initial stage, the friction between the brush and the commutator is large when the rotor rotates, and the sliding loss of the brush is large. As a result, the efficiency of the motor is reduced and the life of the motor (the life of the brush) is reduced.

[0006] Therefore, in order to reduce the difference between the initial pressure and the final pressure and apply a uniform load (pressure) to the brush, a technology using a constant load spring as a brush spring has been proposed (for example, refer to Patent Document 1). The constant load spring is a spiral spring having a spiral portion formed by spirally winding a strip of wire. The constant load spring is configured in such a way that the spiral portion contacts the rear end face of the brush. As a result, the force of the spiral portion restoring when the strip of wire is stretched from the spiral portion can be used to apply a constant load to the rear end face of the brush through the spiral portion.

[0007] However, in conventional motors using a brush spring having a spiral portion, the spiral portion of the brush spring is arranged behind the rear end surface of the brush in the direction in which the brush moves. Therefore, in conventional motors, the length of the brush has to be shortened by at least an amount corresponding to the size of the spiral portion. Therefore, there is a problem that the life of the motor is shortened.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Utility Model Application Laid-Open No. 5-29268 Summary of the invention

[0011] The present disclosure is made to solve such a problem. An object of the present disclosure is to provide a motor with a long life.

[0012] In order to achieve the above-mentioned purpose, a technical solution of the electric motor disclosed in the present invention comprises: a rotor having a rotating shaft extending in an axial direction; a commutator mounted on the rotating shaft; a brush in contact with the commutator; and a brush spring pressing the brush against the commutator. The brush spring comprises: a first volute portion and a second volute portion, each of which is composed of a strip-shaped plate wound in a spiral shape; and a connecting portion connecting the strip-shaped wire material constituting the first volute portion and the strip-shaped wire material constituting the second volute portion. The brush is pressed against the commutator by a load from the connecting portion.

[0013] Preferably, the brush has a front end face in contact with the commutator and a rear end face located on the opposite side of the front end face. Preferably, the connecting portion is in contact with the rear end face of the brush.

[0014] Preferably, the rear end surface of the brush abuts against an end surface of a belt-shaped wire material constituting the connecting portion.

[0015] Preferably, a recessed portion is formed on the rear end surface of the brush, and at least a portion of the connecting portion is inserted into the recessed portion.

[0016] Preferably, the first spiral portion and the second spiral portion are arranged in a manner of clamping the front end portion of the brush, the strip-shaped wire constituting the first spiral portion is led out along one side surface of the brush, and the strip-shaped wire constituting the second spiral portion is led out along the other side surface of the brush.

[0017] Preferably, a technical solution of the electric motor further comprises a brush holder having a brush receiving portion for receiving the brush. Preferably, slits extending along the length direction of the brush are formed on both side surfaces of the brush receiving portion, and the connecting portion protrudes from the slits.

[0018] Preferably, the first spiral portion and the second spiral portion are arranged so as to sandwich the brush housing portion.

[0019] Preferably, the first scroll portion and the second scroll portion are fixed to the brush holder.

[0020] Preferably, the connection portion includes a bent piece formed by bending a portion of a belt-shaped wire material constituting the connection portion, and the bent piece is in surface contact with the rear end surface of the brush.

[0021] Preferably, when there are a plurality of the bent pieces, the plurality of bent pieces include a first bent piece and a second bent piece bent in opposite directions to each other in a height direction of the brush.

[0022] The bent piece may be formed by bending the connecting portion in only one direction.

[0023] Preferably, the connecting portion is offset from a center in a height direction of the brush.

[0024] Preferably, the strip-shaped wire material constituting the first spiral portion, the strip-shaped wire material constituting the second spiral portion, and the strip-shaped wire material constituting the connecting portion are integrated.

[0025] The motor of the present disclosure does not need to shorten the brush even when using a brush spring having a spiral portion. Therefore, the motor of the present disclosure can achieve a long-life motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional view of the electric blower according to the first embodiment, cut along a plane passing through the axis of the rotating shaft and passing through a pair of brushes.

[0027] Figure 2 This is a cross-sectional view of the electric blower according to the first embodiment when cut along a plane passing through the axis of the rotating shaft and passing through a pair of magnets serving as a stator.

[0028] Figure 3 This is an exploded perspective view of the electric blower according to the first embodiment.

[0029] Figure 4 This is a cross-sectional view of the electric blower according to the first embodiment, cut along a plane that passes through a pair of brushes and is orthogonal to the axis of the rotating shaft.

[0030] Figure 5 This is a perspective view of an assembly in which the brush, the brush holder, and the constant load spring in the motor according to the first embodiment are combined, as seen from an oblique front.

[0031] Figure 6 This is a perspective view of an assembly in which the brush, the brush holder, and the constant load spring in the motor according to the first embodiment are combined, as seen from an oblique rear side.

[0032] Figure 7 This is a diagram showing the structure of an assembly in which a brush, a brush holder, and a constant load spring are combined in the motor according to the first embodiment.

[0033] Figure 8 This is a diagram showing an example of the connection between the brush and the pigtail wire.

[0034] Fig. 9 This is a diagram showing another example of the connection between the brush and the pigtail wire.

[0035] Fig.10 This is a perspective view showing a state in which a connecting portion of a constant load spring moves toward a commutator due to wear of the brush in an assembly including a brush, a brush holder, and a constant load spring.

[0036] Fig.11 This is a side view showing a state in which a connecting portion of a constant load spring moves toward a commutator due to wear of the brush in an assembly including a brush, a brush holder, and a constant load spring.

[0037] Fig.12 This is a cross-sectional view showing a brush and a constant load spring provided in a brush holder in a conventional motor.

[0038] Fig.13 This is a diagram showing a brush and a constant load spring in a conventional motor as seen from the back side.

[0039] Fig.14 This is a perspective view showing an assembly in which a brush and a constant load spring are combined in a motor according to a second embodiment.

[0040] Fig.15 This is an enlarged cross-sectional view of a connection portion between a brush and a constant load spring in a motor according to a second embodiment.

[0041] Fig.16 This is a perspective view showing an assembly in which a brush, a brush holder, and a constant load spring are combined in a motor according to Modification 1 of Embodiment 2.

[0042] Fig.17 This is an enlarged cross-sectional view of a connection portion between a brush and a constant load spring in a motor according to Modification 1 of Embodiment 2.

[0043] Fig.18 This is a cross-sectional view showing the structure of a brush and a constant load spring in a motor according to a second modification of the second embodiment.

[0044] Fig.19 This is a cross-sectional view showing the structure of a brush and a constant load spring in a motor according to a third modification of the second embodiment.

[0045] Fig. 20 It is a diagram showing an arrangement example of brushes and constant load springs in a motor according to another modified example. DETAILED DESCRIPTION

[0046] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, the embodiments described below all represent a specific example of the present disclosure. Therefore, the numerical values, constituent elements, configuration positions and connection forms of constituent elements, and processes and the order of processes shown in the following embodiments are examples, and the main purpose is not to limit the present disclosure. Therefore, the constituent elements of the following embodiments that are not recorded in the independent claims representing the highest concept of the present disclosure are described as arbitrary constituent elements.

[0047] In this specification and the drawings, the X-axis, Y-axis, and Z-axis represent three axes of a three-dimensional orthogonal coordinate system. The X-axis and the Y-axis are mutually orthogonal and are both orthogonal to the Z-axis. In this embodiment, the Z-axis direction is the direction in which the axis C of the rotation shaft 13 extends.

[0048] Each figure is a schematic diagram and is not necessarily a rigorous illustration. In each figure, the same figure mark is given to the structure that is essentially the same as other figures, and repeated descriptions are omitted or simplified. In this specification, the terms "upper" and "lower" do not necessarily refer to the upper direction (vertically above) and the lower direction (vertically below) in absolute spatial cognition.

[0049] (Implementation Method 1)

[0050] use Figure 1 to Figure 3 The overall structure of electric blower 1 equipped with electric motor 2 according to the first embodiment will be described. Figure 1 This is a cross-sectional view (XZ cross-sectional view) of electric blower 1 according to Embodiment 1, when cut along a plane passing through axis C of rotating shaft 13 and passing through a pair of brushes 60 . Figure 2 This is a cross-sectional view (YZ cross-sectional view) of the electric blower 1 according to the first embodiment when cut along a plane passing through the axis C of the rotating shaft 13 and passing through a pair of magnets 21 as the stator 20. Figure 1 and Figure 2 In FIG. 1 , the flow of air flowing in electric blower 1 when rotary fan 3 rotates is indicated by thick arrows. Figure 3 This is an exploded perspective view of electric blower 1 according to Embodiment 1.

[0051] like Figure 1 to Figure 3 As shown, the electric blower 1 includes a motor 2, a rotary fan 3, an air guide 4, and a fan housing 5. The motor 2 includes a rotor 10 and a stator 20. The rotary fan 3 is mounted on a rotary shaft 13 of the motor 2. Air exhausted from the rotary fan 3 flows into the air guide 4. The fan housing 5 accommodates the rotary fan 3. The electric blower 1 is used in, for example, an electric vacuum cleaner.

[0052] The motor 2 is a fan motor that rotates the rotary fan 3. As an example, the motor 2 is a DC motor that uses a DC power supply as an input. The motor 2 is a brushed commutator motor.

[0053] like Figure 1 to Figure 3 As shown, the motor 2 includes a rotor 10, a stator 20, a yoke 30, a frame 40, a bracket 50, a brush 60, a brush holder 70, and a constant load spring 80 as a brush spring. The rotor 10, the stator 20, and the yoke 30 are arranged in the frame 40. The detailed structure of each component of the motor 2 will be described later.

[0054] The rotary fan 3 draws air into a housing formed by a frame 40 and a fan housing 5. As an example, the rotary fan 3 is a centrifugal fan capable of obtaining a relatively high suction pressure. Wind pressure is generated by the rotation of the rotary fan 3. Due to the generated wind pressure, air is sucked in from an air inlet 5c of the fan housing 5. The sucked air is discharged from the rotary fan 3. The air discharged from the rotary fan 3 flows into the air guide 4. The rotary fan 3 is made of, for example, a resin material or a metal material such as aluminum.

[0055] As an example, the rotary fan 3 includes: a first side plate provided with an air inlet; a second side plate facing the first side plate with a predetermined gap therebetween; and a plurality of fan blades sandwiched between the first side plate and the second side plate. The plurality of fan blades are each plate-shaped and curved in an arc shape. The plurality of fan blades are radially arranged to form a vortex.

[0056] The air guide 4 has a function of forming a flow path of air flow. For example, the air guide 4 rectifies and discharges the air sucked from the air inlet 5c of the fan housing 5 by the rotation of the rotary fan 3. The air discharged from the air guide 4 flows into the inside of the frame 40 via the bracket 50. In addition, the air discharged from the air guide 4 is discharged not only into the inside of the frame 40, but also to the outside of the frame 40 via the bracket 50.

[0057] The air guide 4 includes a main body 4a, an annular ring 4b surrounding the main body 4a with a gap therebetween, and a plurality of connecting plates 4c connecting the main body 4a and the ring 4b. The gap between the main body 4a and the ring 4b serves as a ventilation path.

[0058] The main body 4a is a circular plate body having a through hole for fixing to the bracket 50. The annular portion 4b functions as a supporting portion for supporting the end of the side wall portion 5b of the fan housing 5 in the direction in which the axis C of the rotating shaft 13 extends (thrust direction). The plurality of connecting plates 4c function as guide plates for forming a flow path for airflow. Specifically, the plurality of connecting plates 4c are plate shapes that are curved in an arc shape. The plurality of connecting plates 4c are radially arranged from the through hole of the main body 4a toward the outside to form a vortex. The air guide 4 is made of, for example, a resin material. However, the air guide 4 may also be made of a metal material.

[0059] The fan case 5 is a housing that accommodates the rotary fan 3. The fan case 5 is a cover that covers the rotary fan 3 and the air guide 4. As an example, the fan case 5 is a metal cover made of a metal material. However, the fan case 5 may also be a resin cover made of a resin material.

[0060] The fan housing 5 includes a cover 5a covering the upper portion of the rotary fan 3 and the air guide 4, and a side wall 5b covering the side portion of the rotary fan 3 and the air guide 4. The fan housing 5 includes an air inlet 5c (inlet) for taking in external air. The air inlet 5c is a circular through hole provided in the center of the cover 5a.

[0061] The fan case 5 is fixed to the bracket 50. The fan case 5 is fixed to the bracket 50 via the air guide 4. A fan case gasket having an opening corresponding to the air intake port 5c may be attached to the air intake port 5c of the fan case 5.

[0062] In the electric blower 1 configured as described above, when the rotor 10 of the motor 2 rotates, the rotary fan 3 rotates. Thus, in the electric blower 1, air is sucked into the inside of the fan case 5 from the air inlet 5c of the fan case 5. Thus, the air flows into the inside of the rotary fan 3. The air sucked into the rotary fan 3 is compressed into high pressure by the fan blades of the rotary fan 3. The compressed air is discharged radially outward from the outer peripheral side of the rotary fan 3. The air discharged from the rotary fan 3 flows into the air guide 4 along the side wall portion 5b of the fan case 5. The air flowing into the air guide 4 reaches the bracket 50 via the ventilation path of the air guide 4.

[0063] Part of the air reaching the bracket 50 flows into the inside of the frame 40 through the bracket 50. The inflowing air passes through the inside of the frame 40 and is discharged to the outside from the exhaust port 40b of the frame 40. That is, the air flowing into the inside of the frame 40 cools the heat generating components (windings, etc.) of the motor 2 and is discharged to the outside of the electric blower 1.

[0064] On the other hand, another part of the air reaching bracket 50 does not pass through the inside of frame 40, but is directly discharged to the outside of electric blower 1 via bracket 50. Thus, another part of the air reaching bracket 50 can be discharged to the outside of electric blower 1 without causing loss due to passing through the inside of frame 40.

[0065] Reference Figure 1 to Figure 3 The detailed structure of each member included in the electric motor 2 will be described.

[0066] like Figure 1 and Figure 2 As shown, the rotor 10 of the motor 2 is arranged with a small air gap between the stator 20. The rotor 10 is an inner rotor. The rotor 10 is arranged inside the stator 20. The rotor 10 has a rotating shaft 13. The rotor 10 rotates with the axis C of the rotating shaft 13 as the rotation center under the action of the magnetic force generated by the stator 20.

[0067] The rotor 10 generates a magnetic force acting on the stator 20. Specifically, the direction of the main magnetic flux generated by the rotor 10 is a direction orthogonal to the direction in which the axis C of the rotating shaft 13 extends. The rotor 10 is an armature. The rotor 10 has a rotor core 11 (rotor core) mounted on the rotating shaft 13, a winding coil 12 wound on the rotor core 11, the rotating shaft 13, and a commutator 14. Figure 1 to Figure 3 In FIG. 1 , a winding coil 12 is schematically shown.

[0068] The rotor core 11 is an armature core wound with a winding coil 12. The rotor core 11 is a laminated body formed by laminating a plurality of electromagnetic steel sheets in a direction in which the axis C of the rotating shaft 13 extends. The rotor core 11 is not limited to a laminated body of electromagnetic steel sheets. The rotor core 11 may also be a block made of a magnetic material.

[0069] The rotor core 11 has a plurality of teeth protruding radially outward from the rotating shaft 13. The plurality of teeth extend radially in a direction (radial direction) perpendicular to the axis C of the rotating shaft 13. The plurality of teeth are magnetic poles. The plurality of teeth generate magnetic force acting on the stator 20 by passing current through the winding coil 12 wound around each tooth.

[0070] The winding coil 12 is wound around the rotor core 11. Specifically, the winding coil 12 is wound around a plurality of teeth of the rotor core 11. The winding coil 12 may be wound around the rotor core 11 via an insulator. The winding coil 12 is electrically connected to a commutator segment 14a of the commutator 14. When current flows through the winding coil 12 via the commutator 14, a magnetic force acting on the stator 20 is generated at each tooth of the rotor core 11.

[0071] The rotating shaft 13 is fixed to the center of the rotor core 11. The rotating shaft 13 is a shaft including the axis C. The rotating shaft 13 is a longitudinally long rod-shaped member such as a metal rod. The axis C of the rotating shaft 13 becomes the center when the rotor 10 rotates. The length direction (extension direction) of the rotating shaft 13 is the direction in which the axis C extends (axial direction).

[0072] The rotating shaft 13 is fixed to the rotor core 11 in a state of extending to both sides of the rotor core 11 in the direction in which the axis C of the rotating shaft 13 extends and penetrating the rotor core 11. Specifically, the rotating shaft 13 is fixed to the rotor core 11 by being inserted into a through hole provided at the center of the rotor core 11. The rotating shaft 13 is fixed to the rotor core 11 by, for example, being pressed into or shrink-fitted into the through hole of the rotor core 11.

[0073] The rotating shaft 13 is rotatably supported by the first bearing 15 and the second bearing 16. Specifically, the first portion 13a of the rotating shaft 13 protruding from the rotor core 11 to one side is supported by the first bearing 15. The second portion 13b of the rotating shaft 13 protruding from the rotor core 11 to the other side is supported by the second bearing 16. As an example, the first bearing 15 and the second bearing 16 are bearings such as ball bearings. In this way, the rotating shaft 13 is supported by the first bearing 15 and the second bearing 16 in a rotatable state. The first bearing 15 is fixed to the bracket 50. The second bearing 16 is fixed to the bottom of the frame 40. That is, the bracket 50 is the first bracket. The frame 40 is the second bracket.

[0074] The first portion 13a of the rotary shaft 13 protrudes from the first bearing 15. The rotary fan 3 is attached to the tip portion of the first portion 13a of the rotary shaft 13 protruding from the first bearing 15.

[0075] The commutator 14 is attached to the rotating shaft 13. Therefore, the commutator 14 rotates together with the rotating shaft 13. The commutator 14 is attached to the second portion 13b of the rotating shaft 13. Specifically, the commutator 14 is disposed at a portion of the rotating shaft 13 between the rotor core 11 and the second bearing 16.

[0076] The commutator 14 includes a plurality of segments 14a arranged in an annular shape so as to surround the rotating shaft 13. The plurality of segments 14a are insulated and separated from each other in the rotation direction of the rotating shaft 13. As described above, the plurality of segments 14a are electrically connected to the winding coil 12, respectively.

[0077] like Figure 2As shown, the stator 20 is opposite to the rotor 10. Specifically, the stator 20 is opposite to the rotor core 11. The stator 20 is arranged on the radial outer peripheral side of the rotor core 11. The stator 20 is a plurality of magnets 21 arranged at intervals from each other throughout the circumference of the rotor 10. The magnet 21 is a magnetic field generator that forms a magnetic flux for generating torque. The magnet 21 is, for example, a permanent magnet having an S pole and an N pole. The plurality of magnets 21 are arranged so that the N pole and the S pole exist alternately along the rotation direction (circumferential direction) of the rotating shaft 13.

[0078] The stator 20 includes two magnets 21 facing each other across the rotor 10 . A small air gap exists between the inner surface of each magnet 21 and the outer peripheral surface of the rotor 10 (rotor core 11 ). The magnets 21 are fixed to the yoke 30 .

[0079] like Figure 2 As shown, the yoke 30 surrounds the magnet 21. The yoke 30 and the magnet 21 together form a magnetic circuit (magnetic field). Therefore, the yoke 30 can also be regarded as a part of the stator 20. The yoke 30 is a cylindrical shape with a constant thickness. The yoke 30 surrounds the rotor 10 and the stator 20 (magnet 21) as a whole. The yoke 30 is made of a magnetic material such as iron.

[0080] like Figure 1 and Figure 2 As shown, frame 40 is a frame (casing) that accommodates components constituting motor 2 such as rotor 10 and stator 20. Frame 40 is an outer member (housing) of electric blower 1 and motor 2. Frame 40 can be made of a metal material such as aluminum.

[0081] In addition, if Figure 2 and Figure 3 As shown, a plurality of exhaust ports 40 b for exhausting air sucked by the rotation of the rotary fan 3 are respectively formed on the side wall portion and the bottom portion of the frame 40 .

[0082] like Figure 1 and Figure 2 As shown, a gap G serving as a ventilation path is formed between the outer surface of the yoke 30 and the inner surface of the frame 40 along the direction in which the axis C of the rotating shaft 13 extends (rotating axis direction). A plurality of gaps G are formed.

[0083] like Figure 1 to Figure 3 As shown, the frame 40 has a bulging portion 41 that bulges radially outward on a portion of the side wall of the frame 40. The gap G is a space region between the bulging portion 41 and the yoke 30. The bulging portion 41 is a rib formed as a protrusion. The bulging portion 41 can be formed, for example, by stamping the side wall of the frame 40.

[0084] like Figure 1 and Figure 2As shown, the bracket 50 covers the opening 40a of the frame 40. The bracket 50 does not completely block the opening 40a of the frame 40, but covers a portion of the opening 40a of the frame 40. That is, when the bracket 50 is attached to the frame 40, the air rectified by the air guide 4 flows into the frame 40.

[0085] The bracket 50 is provided with a plurality of through holes as openings for the air rectified by the air guide 4 to pass through. Figure 1 to Figure 3 As shown, the bracket 50 is provided with four first through holes 51 located radially inwardly and four second through holes 52 located radially outwardly of the first through holes 51 .

[0086] The bracket 50 is fixed to the frame 40. For example, the bracket 50 and the frame 40 are fixed together by engaging the bracket 50 with a portion (recessed portion) between two adjacent bulging portions 41 in the side wall portion of the frame 40.

[0087] Next, refer to Figure 1 to Figure 3 and use Figures 4 to 7 The detailed structures of the brush 60 , the brush holder 70 , and the constant load spring 80 will be described. Figure 4 It is a cross-sectional view (XY cross-sectional view) of electric blower 1 according to Embodiment 1, when cut along a plane passing through a pair of brushes 60 and perpendicular to axis C of rotating shaft 13 . Figure 5 This is a perspective view of an assembly in which the brush 60 , the brush holder 70 , and the constant load spring 80 in the motor 2 according to the first embodiment are combined, when viewed from an oblique front. Figure 6 This is a perspective view of an assembly in which the brush 60 , the brush holder 70 , and the constant load spring 80 in the motor 2 according to the first embodiment are combined, as seen from an oblique rear side. Figure 7 1 is a diagram showing the structure of an assembly in which the brush 60, the brush holder 70, and the constant load spring 80 are combined in the motor 2 according to the first embodiment. Figure 7 In the figure, (a) is a top view, (b) is a side view, (c) is a front view, (d) is a rear view, (e) is a cross-sectional view taken along line e-e of (b), and (f) is a cross-sectional view taken along line f-f of (a).

[0088] like Figure 1 , Figure 2 and Figure 4 As shown, the brush 60 contacts the commutator 14. Specifically, the brush 60 contacts the commutator segments 14a of the commutator 14. The brush 60 is a power supply brush (power supply brush) that supplies power to the winding coil 12 of the rotor 10. For example, a braided wire (see FIG. 1 ) electrically connected to a power supply terminal that receives power from an external power supply is connected to the brush 60. Figure 8 , Fig. 9The pigtail wire 90 described later) contacts the commutator segment 14a through the brush 60, and the current (armature current) supplied to the brush 60 through the pigtail wire flows to the winding coil 12 of the rotor 10 through the commutator segment 14a.

[0089] The brush 60 is made of a conductive conductor. Specifically, the brush 60 is a carbon brush made of carbon. As an example, the brush 60 is a metal graphite brush containing a metal such as copper and carbon. The brush 60 can be made by crushing a mixture of graphite powder, copper powder, a binder resin, and a curing agent, compressing it into a rectangular parallelepiped, and firing it. The brush 60 is longitudinally long in its initial state before wear. As an example, the brush 60 is a substantially longitudinally long rectangular parallelepiped.

[0090] like Figure 4 As shown, the brush 60 has a front end surface 61 that contacts the commutator 14 and a rear end surface 62 that is located on the opposite side to the front end surface 61 .

[0091] The front end face 61 of the brush 60 is an end face of the front end portion of one end in the longitudinal direction of the brush 60. The front end face 61 is an end face on the rotating shaft 13 side (commutator 14 side) of the brush 60. The front end face 61 is a sliding contact surface that slides with the commutator segment 14a of the commutator 14.

[0092] The rear end face 62 of the brush 60 is an end face of the rear end portion which is the other end in the length direction of the brush 60. The rear end face 62 is an end face of the brush 60 on the side opposite to the rotating shaft 13 side. A recess 63 is provided on the rear end face 62. A connecting portion 83 of a constant load spring 80 is inserted into the recess 63, and the details will be described later.

[0093] like Figure 7 (b) and Figure 7 As shown in (f), the recess 63 is formed in a manner that a portion of the rear end face 62 is recessed toward the front end face 61. That is, the bottom surface of the recess 63 is a portion of the rear end face 62. The recess 63 is formed in a manner that the rear end face 62 is cut out in a rectangular shape when viewed in section. Specifically, the shape of the recess 63 is a rectangle in the XZ section.

[0094] The recess 63 is a groove extending in a direction perpendicular to the longitudinal direction of the brush 60. Figure 4 As shown, the recess 63 is formed from one side surface to the other side surface of the brush 60. The recess 63 can be formed, for example, by cutting off a portion of the flat rear end surface 62 of the rectangular parallelepiped brush using a drill or the like to cut a notch in the rear end surface 62. The recess 63 may be formed not by cutting the flat end surface of the brush 60 but by using a mold when the brush 60 is sintered.

[0095] The brush 60 is pressed against the commutator 14 by the load generated by the constant load spring 80. By pressing the brush 60 against the commutator 14, the brush 60 and the commutator 14 are always in contact during the operation of the motor 2. As a result, the front end surface 61 of the brush 60 is worn due to friction with the commutator 14, and the brush 60 is shortened. That is, as the front end surface 61 of the brush 60 is worn, the rear end surface 62 moves toward the commutator 14.

[0096] like Figure 4 As shown, the brush 60 contacts the commutator segments 14a of the commutator 14 in a direction intersecting the axis C of the rotating shaft 13 (i.e., in a plane intersecting the axis C of the rotating shaft 13, in a radial direction centered on the axis C toward the side of the rotating shaft 13). The brush 60 is arranged so that its length direction becomes a direction (radial direction) orthogonal to the axis C of the rotating shaft 13.

[0097] A plurality of brushes 60 are provided. Specifically, two brushes 60 are provided. In this case, a pair of brushes 60 are provided which are arranged opposite to each other with the commutator 14 sandwiched therebetween. That is, the pair of brushes 60 are arranged opposite to each other with the commutator 14 located in the middle. The commutator 14 rotates together with the rotating shaft 13 by the operation of the motor 2, and the front end surface 61 of each brush 60 continuously contacts all the commutator segments 14a in sequence.

[0098] like Figure 1 As shown, the brush 60 is held by the brush holder 70. Specifically, the brush 60 is held by the brush holder 70 in a manner that allows it to move along a direction (radial direction) that intersects the direction in which the axis C of the rotating shaft 13 extends. The brush holder 70 is fixed to the frame 40. For example, the brush holder 70 is inserted into an opening provided in the frame 40 and fixed to the frame 40 by screws or the like. The brush holder 70 is configured in accordance with the number of the brushes 60. In the present embodiment, two brushes 60 are configured, and therefore two brush holders 70 are also configured.

[0099] like Figure 5 to Figure 7 As shown, the brush holder 70 has a brush receiving portion 71 for receiving the brush 60 as a brush holding portion for holding the brush 60. As an example, the brush receiving portion 71 is a cylindrical portion surrounding the brush 60. The brush receiving portion 71 has a substantially rectangular cylindrical shape that is longitudinally elongated and extends in a direction intersecting with the direction in which the axis C of the rotating shaft 13 extends. The brush holder 70 is a resin molded product made of an insulating resin material.

[0100] Both ends of the brush housing 71 in the longitudinal direction are open. The brush 60 is arranged in the brush housing 71 in a state where the front end surface 61 is exposed from the opening. The brush 60 accommodated in the brush housing 71 protrudes from the opening and contacts the commutator segments 14a of the commutator 14. The brush 60 may be arranged in the brush housing 71 in a state where it is accommodated in a brush box formed of a metal plate.

[0101] like Figure 6 As shown, slits 72 extending along the length direction of the brush 60 are formed on both side surfaces of the brush housing portion 71. Specifically, a first slit 72a extending along the length direction of the brush 60 is formed on one side surface of the brush housing portion 71. A second slit 72b extending along the length direction of the brush 60 is formed on the other side surface of the brush housing portion 71. The first slit 72a and the second slit 72b are arranged in parallel at the same height position.

[0102] like Figure 5 to Figure 7 As shown, a constant load spring 80 is fixed to the brush holder 70. That is, the brush holder 70 not only holds the brush 60, but also holds the constant load spring 80. Specifically, a pair of protrusions 73 are provided on the brush holder 70 as fixing parts for fixing the constant load spring 80. The pair of protrusions 73 protrude outward from both side surfaces of the brush holder 70. The pair of protrusions 73 are provided at the front end portion of the brush holder 70. That is, one of the pair of protrusions 73 protrudes from one side surface of the front end portion of the brush holder 70. The other of the pair of protrusions 73 protrudes from the other side surface of the front end portion of the brush holder 70. As an example, the pair of protrusions 73 are cylindrical in shape. One of the pair of protrusions 73 is inserted into the first volute portion 81 of the constant load spring 80. The other of the pair of protrusions 73 is inserted into the second volute portion 82 of the constant load spring 80. Thus, the first volute portion 81 and the second volute portion 82 are fixed to the pair of protrusions 73. That is, the first scroll portion 81 and the second scroll portion 82 are fixed to the brush holder 70 .

[0103] The constant load spring 80 is a brush spring for pressing the brush 60 against the commutator 14 . The constant load spring 80 is in contact with the brush 60 . The constant load spring 80 directly applies a load to the brush 60 , thereby pressing the brush 60 against the commutator 14 .

[0104] The constant load spring 80 is a spring for applying a uniform load to the brush 60. Figure 5 to Figure 7 As shown, the constant load spring 80 is composed of a strip-shaped wire. The constant load spring 80 is a spiral spring. The constant load spring 80 has a spiral portion (coil portion) formed by spirally winding a strip-shaped wire. The constant load spring 80 has a first spiral portion 81 and a second spiral portion 82 as a pair of spiral portions, each of which is composed of a strip-shaped wire wound in a spiral shape.

[0105] The first volute portion 81 and the second volute portion 82 are arranged so as to sandwich the front end portion of the brush 60. The first volute portion 81 and the second volute portion 82 are arranged so as to sandwich the front end portion of the brush holder 70.

[0106] The first scroll portion 81 and the second scroll portion 82 are formed in a spiral shape by winding around the width direction of the brush 60. That is, the constant load spring 80 is arranged in a manner that the coil surfaces of the first scroll portion 81 and the second scroll portion 82 face the side surface of the brush holder 70. Therefore, the plate surface of the strip-shaped wire material that is drawn out from the first scroll portion 81 and constitutes the first scroll portion 81 and the plate surface of the strip-shaped wire material that is drawn out from the second scroll portion 82 and constitutes the second scroll portion 82 are parallel to the plane (XY plane) that is orthogonal to the axis C of the rotating shaft 13. The winding center axis of the first scroll portion 81 and the winding center axis of the second scroll portion 82 are consistent.

[0107] As described above, the first and second volute portions 81 and 82 are fixed to the brush holder 70 by being fitted over the pair of protrusions 73 provided on the brush holder 70. That is, the first and second volute portions 81 and 82 serve as fixed ends of the constant load spring 80.

[0108] The constant load spring 80 also has a connecting portion 83 that connects the strip-shaped wire that constitutes the first volute portion 81 and the strip-shaped wire that constitutes the second volute portion 82. The connecting portion 83 is composed of a strip-shaped wire in the same manner as the first volute portion 81 and the second volute portion 82. The wire that constitutes the first volute portion 81, the strip-shaped wire that constitutes the second volute portion 82, and the strip-shaped wire that constitutes the connecting portion 83 are integrated. That is, the constant load spring 80 is composed of a single wire. In addition, the wire that constitutes the first volute portion 81, the strip-shaped wire that constitutes the second volute portion 82, and the strip-shaped wire that constitutes the connecting portion 83 have the same plate width. However, this is not limited to this.

[0109] The coupling portion 83 applies a load to the rear end surface 62 of the brush 60 , thereby pressing the brush 60 against the commutator 14 . That is, the brush 60 is pressed against the commutator 14 by the load from the coupling portion 83 .

[0110] The connecting portion 83 contacts the rear end face 62 of the brush 60. In this case, the rear end face 62 of the brush 60 contacts the end face (side face) of the strip-shaped wire material constituting the connecting portion 83. That is, the rear end face 62 of the brush 60 contacts a portion of the metal plate constituting the connecting portion 83 that is equivalent to the plate thickness. Specifically, a recess 63 is formed on the rear end face 62 of the brush 60, and at least a portion of the connecting portion 83 is inserted into the recess 63. Therefore, the end face of the strip-shaped wire material constituting the connecting portion 83 contacts the bottom surface of the recess 63.

[0111] There is a gap between the main surface of the strip-shaped wire material constituting the connecting portion 83 and the inner surface of the recess 63. However, the gap may not exist. In this case, the connecting portion 83 may also be pressed into the recess 63. Thus, the connecting portion 83 can be fixed to the recess 63.

[0112] The connection portion 83 connects the strip-shaped wires drawn out from the first and second spiral portions 81 and 82 disposed so as to sandwich the brush 60. Therefore, the connection portion 83 protrudes from the rear end surface of the brush 60 in the Y-axis direction in a plan view.

[0113] The first scroll portion 81 and the second scroll portion 82 are arranged so as to sandwich the brush housing portion 71 of the brush holder 70. Therefore, the connecting portion 83 protrudes from the slits 72 provided on both side surfaces of the brush housing portion 71. Specifically, the connecting portion 83 protrudes from the first slit 72a formed in the brush housing portion 71 and protrudes from the second slit 72b formed in the brush housing portion 71.

[0114] The constant load spring 80 is composed of a metal plate in a strip shape formed into a prescribed shape. The shape of the strip-shaped metal plate constituting the constant load spring 80 before forming the first scroll portion 81 and the second scroll portion 82 is in the shape of a Japanese コ shape when viewed from above. In this case, the first scroll portion 81 can be formed by spirally winding a strip of wire material constituting one leg of the metal plate constituting the Japanese コ shape for multiple turns. Similarly, the second scroll portion 82 can be formed by spirally winding a strip of wire material constituting the other leg of the metal plate constituting the Japanese コ shape for multiple turns. Therefore, the shape of the portion of the first scroll portion 81 and the second scroll portion 82 that is equivalent to one turn is circular.

[0115] The first and second spiral portions 81 and 82 configured in this manner have a spring force (spring restoring force) that attempts to restore the belt-shaped wire material when the belt-shaped wire material is pulled out from the first and second spiral portions 81 and 82 .

[0116] The thickness of the metal plate constituting the constant load spring 80 is, for example, less than 0.1 mm. As an example, the thickness of the metal plate constituting the constant load spring 80 is 0.08 mm or 0.05 mm. The thickness of the metal plate constituting the constant load spring 80 is not limited to less than 0.1 mm. As long as the constant load spring 80 can be wound into a spiral shape, the thickness of the metal plate constituting the constant load spring 80 may be thicker than 0.1 mm. The shape of the strip-shaped metal plate constituting the constant load spring 80 may not be a Japanese U-shape.

[0117] like Figure 5 to Figure 7As shown, for the constant load spring 80 provided in the brush holder 70, the strip-shaped wire material constituting the first volute portion 81 is led out along one side surface of the brush 60. The strip-shaped wire material constituting the second volute portion 82 is led out along the other side surface of the brush 60. Specifically, the strip-shaped wire material constituting the first volute portion 81 is led out along one side surface of the brush storage portion 71 of the brush holder 70 and toward the rear end surface 62 of the brush 60. The strip-shaped wire material constituting the second volute portion 82 is led out along the other side surface of the brush storage portion 71 of the brush holder 70 and toward the rear end surface 62 of the brush 60.

[0118] The brush 60, the brush holder 70, and the constant load spring 80 thus constructed are assembled to the motor 2 as follows. Specifically, the brush 60 is inserted into the brush housing portion 71 of the brush holder 70 toward the commutator 14, and the connecting portion 83 of the constant load spring 80 is inserted into the recess 63 provided on the rear end surface 62 of the brush 60. The first volute portion 81 and the second volute portion 82 of the constant load spring 80 are pulled toward the commutator 14 side, thereby leading out a strip-shaped wire from the first volute portion 81 and the second volute portion 82, and the first volute portion 81 and the second volute portion 82 are covered and hooked on the pair of protrusions 73. In this way, the constant load spring 80 can be provided on the brush holder 70.

[0119] At this time, by drawing out the strip-shaped wire from the first volute 81 and the second volute 82, a load is generated in which the strip-shaped wire constituting the first volute 81 and the second volute 82 attempts to restore. Under the action of the load generated by the first volute 81 and the second volute 82 at this time, the connecting portion 83 in contact with the rear end surface 62 of the brush 60 pulls the brush 60 toward the commutator 14. That is, the connecting portion 83 presses the brush 60 toward the commutator 14. In this way, the constant load spring 80 presses the brush 60 against the commutator 14 by the load generated by the first volute 81 and the second volute 82.

[0120] As described above, the brush 60 is connected to the pigtail wire 90 which is electrically connected to the power terminal. Figure 8 1 is a diagram showing an example of the connection between the brush 60 and the pigtail wire 90 . Fig. 9 FIG. 1 is a diagram showing another example of the connection between the brush 60 and the pigtail wire 90. Figure 8 As shown, the braided wire 90 is connected to the side of the brush 60. Fig. 9 As shown, the pigtail wire 90 is connected to the bottom surface of the brush 60. Thus, there is no particular restriction on the connection position of the pigtail wire 90 to the brush 60. That is, the connection position between the brush 60 and the pigtail wire 90 has a high degree of freedom.

[0121] In the motor 2 constructed as described above, the current supplied to the brush 60 flows as an armature current (drive current) through the winding coil 12 of the rotor 10 via the commutator 14, thereby generating a magnetic flux in the rotor 10. The magnetic force generated by the interaction between the magnetic flux generated by the rotor 10 and the magnetic flux generated by the stator 20 becomes a torque that rotates the rotor 10. At this time, the direction of the current flow is switched according to the positional relationship when the commutator segments 14a of the commutator 14 contact the brush 60. By switching the direction of the current flow in this way, a rotational force of a constant direction is generated by the repulsive force and attractive force of the magnetic force generated between the rotor 10 and the stator 20. Under the action of this rotational force, the rotor 10 rotates around the axis C of the rotating shaft 13. As a result, in the electric blower 1, the rotating fan 3 mounted on the rotating shaft 13 rotates.

[0122] When the rotor 10 rotates in this way, the front end face 61 of the brush 60 in contact with the commutator 14 wears. At this time, the brush 60 always receives a constant load (pressing force) from the constant load spring 80 and is pressed against the commutator 14. As a result, as the front end face 61 of the brush 60 wears due to friction with the commutator 14, the brush 60 slides toward the commutator 14 in the brush housing 71 of the brush holder 70. That is, the rear end face 62 of the brush 60 moves toward the commutator 14.

[0123] At this time, the constant load spring 80 applies a load generated by pulling out the strip-shaped wire from the first spiral portion 81 and the second spiral portion 82 to the brush 60 via the connecting portion 83 . As a result, the brush 60 is pressed by the connecting portion 83 and pressed against the commutator 14 . Fig.10 This is a perspective view showing a state in which the connection portion 83 of the constant load spring 80 moves toward the commutator 14 due to wear of the brush 60 in an assembly composed of the brush 60 , the brush holder 70 , and the constant load spring 80 . Fig.11 1 is a side view showing a state in which the connecting portion 83 of the constant load spring 80 moves toward the commutator 14 due to wear of the brush 60 in the assembly composed of the brush 60, the brush holder 70 and the constant load spring 80. Fig.10 and Fig.11 As shown, the coupling portion 83 of the constant load spring 80 moves toward the commutator 14 as the front end surface 61 of the brush 60 wears.

[0124] Specifically, if Fig.10 and Fig.11 As shown in FIG. 1 , the first volute 81 and the second volute 82 of the constant load spring 80 try to restore by the spring restoring force. Therefore, as the brush 60 wears, the strip-shaped wire material constituting the first volute 81 and the second volute 82 are respectively rolled back to the original state. As a result, the connecting portion 83 connecting the first volute 81 and the second volute 82 moves toward the commutator 14 while pressing the brush 60 toward the commutator 14.

[0125] Next, the effects of the motor 2 of the present embodiment will be described in comparison with a conventional motor 2X. Fig.12 It is a cross-sectional view showing the brush 60 and the constant load spring 80X provided in the brush holder 70X in the conventional motor 2X. Fig.13 This is a diagram of a brush 60 and a constant load spring 80X in a conventional motor 2X as seen from the back side.

[0126] like Fig.12 As shown, in the conventional motor 2X, the constant load spring 80X has a volute portion 81X. The constant load spring 80X is arranged in such a manner that the volute portion 81X is located in the brush storage portion 71X of the brush holder 70X together with the brush 60. At this time, the volute portion 81X of the constant load spring 80X is formed in a spiral shape by winding centered on the axial direction of the rotating shaft of the motor 2X. The volute portion 81X of the constant load spring 80X is arranged behind the rear end surface 62 of the brush 60. That is, the volute portion 81X is arranged in the range where the brush 60 can slide. Therefore, in the conventional motor 2X, the length of the brush 60 has to be shortened by an amount corresponding to the size of the volute portion 81X. As a result, the life of the motor 2X is shortened. On the other hand, without shortening the length of the brush 60, the length of the brush holder 70X has to be lengthened. As a result, the motor 2X is enlarged.

[0127] In the electric motor 2X using the constant load spring 80X as the brush spring, the height of the brush 60 is determined by the plate width of the strip of wire constituting the constant load spring 80X. Specifically, first of all, from the perspective of the load generated by the spiral portion 81X and the manufacturing aspect of the constant load spring 80X, the plate width of the strip of wire constituting the constant load spring 80X needs to be greater than a certain width. Furthermore, in order to suppress the shaking of the brush 60 that bears the load (pressing force) of the spiral portion 81X, a coupling margin of the spiral portion 81X is required at the rear end face 62 of the brush 60X. Therefore, if Fig.13 As shown in FIG. 1 , the height of the brush 60 needs to be higher than the height of the spiral portion 81X. That is, the height of the brush 60 needs to be greater than the plate width of the strip-shaped wire material constituting the constant load spring 80X. Thus, if the constant load spring 80X is used as the brush spring and the spiral portion 81X is arranged behind the brush 60, the height of the brush 60 has to be increased. Therefore, it becomes difficult to reduce the thickness of the motor 2X.

[0128] In contrast, in the motor 2 of the present embodiment, a constant load spring 80 having a first spiral portion 81, a second spiral portion 82, and a connecting portion 83 is used as a brush spring for pressing the brush 60 against the commutator 14. The brush 60 is pressed against the commutator 14 by the load from the connecting portion 83 of the constant load spring 80.

[0129] According to this structure, even if the first volute 81 and the second volute 82 are not arranged behind the rear end surface 62 of the brush 60, the brush 60 can be pressed against the commutator 14 by the constant load spring 80. That is, even if the first volute 81 and the second volute 82 are not arranged in the range where the brush 60 can slide, the load of the first volute 81 and the second volute 82 can be applied to the brush 60. Therefore, even if the constant load spring 80 is used as the brush spring, it is not necessary to shorten the length of the brush 60. Therefore, a long-life motor 2 can be achieved.

[0130] Furthermore, the first scroll portion 81 and the second scroll portion 82 do not need to be arranged on the rear end surface 62 of the brush 60. Therefore, it is not necessary to increase the height (length in the Z-axis direction) of the brush 60 as in the conventional motor 2X. In other words, it is not necessary to make the height of the brush 60 larger than the plate width of the strip-shaped wire material constituting the constant load spring 80. Thus, even when the constant load spring 80 is used as the brush spring, a small motor 2 can be easily realized.

[0131] In the electric motor 2 of the present embodiment, the coupling portion 83 of the constant load spring 80 is in contact with the rear end surface 62 of the brush 60 .

[0132] Alternatively, another component may be inserted between the connecting portion 83 of the constant load spring 80 and the rear end face 62 of the brush 60 to indirectly apply the load generated by the connecting portion 83 to the brush 60. However, it is better to make the connecting portion 83 and the rear end face 62 of the brush 60 directly contact without using another component as in the present embodiment.

[0133] According to this structure, the connection portion 83 can directly apply a load to the rear end face 62 of the brush 60. Therefore, compared with the case where other components are inserted between the connection portion 83 and the rear end face 62 of the brush 60, the load can be stably applied to the rear end face 62 of the brush 60. In addition, since no other components are used, an increase in cost can be suppressed.

[0134] In the electric motor 2 of the present embodiment, the rear end surface 62 of the brush 60 abuts against the end surface of the belt-shaped wire material constituting the connecting portion 83 .

[0135] According to this structure, the strip-shaped wire material constituting the first spiral portion 81, the strip-shaped wire material constituting the second spiral portion 82, and the strip-shaped wire material constituting the connecting portion 83 are integrated into one, whereby the connecting portion 83 can be brought into contact with the rear end face 62 of the brush 60 simply by leading the wire material from the first spiral portion 81 and the second spiral portion 82.

[0136] In the motor 2 of the present embodiment, the recessed portion 63 is formed in the rear end surface 62 of the brush 60 . At least a portion of the connecting portion 83 of the constant load spring 80 is inserted into the recessed portion 63 .

[0137] According to this structure, since the connection part 83 can be fixed at a fixed position, the load can be stably applied to the brush 60. Therefore, the slidability of the brush 60 can be improved.

[0138] In the motor 2 of the present embodiment, the first spiral portion 81 and the second spiral portion 82 of the constant load spring 80 are arranged so as to sandwich the front end portion of the brush 60. The strip-shaped wire material constituting the first spiral portion 81 is led out along one side surface of the brush 60. The strip-shaped wire material constituting the second spiral portion 82 is led out along the other side surface of the brush 60.

[0139] According to this structure, even when the constant load spring 80 having the first spiral portion 81 and the second spiral portion 82 is used, the height of the motor 2 can be reduced by arranging the first spiral portion 81 and the second spiral portion 82 so as to sandwich the front end portion of the brush 60. Therefore, it is easy to realize a small motor 2. Specifically, the first spiral portion 81 and the second spiral portion 82 are arranged so as to sandwich the brush housing portion 71 housing the brush 60.

[0140] In the motor 2 of the present embodiment, slits 72 extending along the longitudinal direction of the brush 60 are formed on both side surfaces of the brush housing portion 71 of the brush holder 70. The connecting portion 83 of the constant load spring 80 protrudes from the slits 72.

[0141] According to this structure, when the brush 60 is worn and the strip-shaped wire material constituting the first spiral portion 81 and the second spiral portion 82 is wound back to the original state, the connecting portion 83 can be slid along the first slit 72a and the second slit 72b toward the commutator 14. That is, the connecting portion 83 can be moved toward the commutator 14 while being held by the brush holder 70. In this way, the first slit 72a and the second slit 72b function as a guide portion when the connecting portion 83 moves toward the commutator 14 side.

[0142] In the motor 2 of the present embodiment, the first spiral portion 81 and the second spiral portion 82 of the constant load spring 80 are fixed to the brush holder 70. That is, in the constant load spring 80, the first spiral portion 81 and the second spiral portion 82 serve as fixed ends.

[0143] According to this structure, the direction of the load generated by the strip-shaped wire material led out from the first scroll portion 81 and the second scroll portion 82 during restoration is not the direction from the first scroll portion 81 and the second scroll portion 82 to the connecting portion 83 side, but the direction from the connecting portion 83 to the first scroll portion 81 and the second scroll portion 82 side (fixed end side). Therefore, when the brush 60 is worn, it is not the first scroll portion 81 and the second scroll portion 82 that move to the connecting portion 83 side, but the connecting portion 83 that moves to the first scroll portion 81 and the second scroll portion 82 side. A load is generated in the direction from the connecting portion 83 to the first scroll portion 81 and the second scroll portion 82 side, thereby making it possible to pull the rear end face 62 of the brush 60 by the connecting portion 83. As a result, the brush 60 is pressed toward the commutator 14 by the constant load spring 80.

[0144] In the electric motor 2 of the present embodiment, the strip-shaped wire material constituting the first spiral portion 81 , the strip-shaped wire material constituting the second spiral portion 82 , and the strip-shaped wire material constituting the connecting portion 83 are integrated.

[0145] According to this structure, the constant load spring 80 can be formed of a single metal plate of a predetermined shape. Thus, the constant load spring 80 including the first spiral portion 81, the second spiral portion 82, and the connecting portion 83 that contacts the brush 60 can be manufactured at low cost.

[0146] As described above, the motor 2 of the present embodiment includes: the rotor 10 having the rotating shaft 13 extending in the axial direction; the commutator 14 mounted on the rotating shaft 13; the brush 60 in contact with the commutator 14; and the brush spring 80 pressing the brush 60 against the commutator 14. The brush spring 80 includes: the first volute 81 and the second volute 82, each of which is formed of a strip-shaped plate wound in a spiral shape; and the connecting portion 83 connecting the strip-shaped wire material forming the first volute 81 and the strip-shaped wire material forming the second volute 82. The brush 60 is pressed against the commutator 14 by the load from the connecting portion 83.

[0147] According to this configuration, even when the brush spring having the spiral portion is used, there is no need to shorten the brushes of the motor 2. Therefore, the motor 2 can achieve a long life.

[0148] (Implementation Method 2)

[0149] use Fig.14 and Fig.15 Implementation method 2 will be described. Fig.14 This is a perspective view showing an assembly in which the brush 60 and the constant load spring 80A are combined in the electric motor 2A according to the second embodiment. Fig.15 It is an enlarged cross-sectional view of a connection portion between the brush 60 and the constant load spring 80A in the electric motor 2A according to the second embodiment.

[0150] The motor 2A is different from the motor 2 of the first embodiment in the structure of the constant load spring 80A. Fig.14 and Fig.15 As shown, in the constant load spring 80A, a bent piece 84 is formed at a connecting portion 83A that contacts the rear end surface 62 of the brush 60 .

[0151] The bending piece 84 is formed by bending a portion of the strip-shaped wire material constituting the connecting portion 83. The bending piece 84 is a cut and erected piece formed by cutting and erecting a portion of the strip-shaped wire material constituting the connecting portion 83A. For example, the bending piece 84 can be formed by cutting and erecting a portion of the metal plate constituting the connecting portion 83A in a rectangular shape. In addition, the bending piece 84 is formed in a manner of being erected on the main surface of the strip-shaped wire material constituting the connecting portion 83A. Specifically, in the connecting portion 83A, the angle formed by the main surface of the bending piece 84 and the main surface of the portion where the bending piece 84 is not formed is approximately 90°. That is, the bending piece 84 is cut and erected at an angle of 90°. The bending piece 84 thus formed is in surface contact with the rear end face 62 of the brush 60.

[0152] like Fig.14 As shown, a plurality of bent pieces 84 are formed in the connecting portion 83A. The plurality of bent pieces 84 include a first bent piece 84a and a second bent piece 84b bent in opposite directions to each other in the height direction (Z-axis direction) of the brush 60. The first bent piece 84a is bent downward. The second bent piece 84b is bent upward. Specifically, the first bent piece 84a is formed by cutting and erecting a portion of the strip-shaped wire material constituting the connecting portion 83A downward. The second bent piece 84b is formed by cutting and erecting a portion of the strip-shaped wire material constituting the connecting portion 83A upward.

[0153] like Fig.14 As shown, in the connection portion 83A, two first bending pieces 84a and one second bending piece 84b are formed as the bending pieces 84. However, this is not limited to this. The total number of bending pieces 84 is not limited to 3. The combination of the number of the first bending pieces 84a and the number of the second bending pieces 84b is also not limited to this.

[0154] The motor 2A has the same structure as the motor 2 of the first embodiment except for the structure of the constant load spring 80A.

[0155] Therefore, the motor 2A has the same effect as the motor 2 of the above-mentioned embodiment 1. For example, in the motor 2A of this embodiment, similarly to the above-mentioned embodiment 1, the brush 60 is pressed against the commutator 14 by the constant load spring 80A having the first spiral portion 81, the second spiral portion 82 and the connecting portion 83.

[0156] According to this structure, even when the constant load spring 80A is used as the brush spring, there is no need to shorten the length of the brush 60. Therefore, a motor 2A with a long life can be realized. In addition, there is no need to increase the height of the brush 60. Therefore, a small motor 2A can be easily realized.

[0157] In the motor 2A of the present embodiment, the connection portion 83A of the constant load spring 80A has a bent piece 84 formed by partially bending a strip-shaped wire material constituting the connection portion 83A. The bent piece 84 is in surface contact with the rear end surface 62 of the brush 60 .

[0158] According to this structure, the contact area between the rear end surface 62 of the brush 60 and the connection portion 83A can be increased. Therefore, the load can be applied to the brush 60 more stably through the connection portion 83A. Therefore, the slidability of the brush 60 can be improved.

[0159] In the motor 2A of the present embodiment, the connection portion 83A is formed with a plurality of bent pieces 84. The plurality of bent pieces 84 include a first bent piece 84a and a second bent piece 84b bent in opposite directions in the height direction of the brush 60.

[0160] According to this structure, the load can be applied to the brush 60 uniformly in the height direction of the brush 60. Therefore, the load generated by the connecting portion 83 can be applied to the brush 60 more stably. Therefore, the slidability of the brush 60 can be further improved.

[0161] In the present embodiment, the bent pieces 84 are formed on both sides in the height direction of the brush 60. However, the present invention is not limited to this. Fig.16 This is a perspective view showing an assembly in which the brush 60 , the brush holder, and the constant load spring 80B are combined in the electric motor 2B according to the first modification of the second embodiment. Fig.17 2 is an enlarged cross-sectional view showing the connection portion between the brush 60 and the constant load spring 80B in the motor 2B of the modification 1 of the embodiment 2. Fig.16 and Fig.17 As in the motor 2B shown in FIG. 1 , the bent piece 84B formed at the connection portion 83B of the constant load spring 80B is bent only in one direction. Specifically, the bent piece 84B is bent only toward the upper side in the height direction of the brush 60. In this case, the cross-sectional shape of the connection portion 83B is L-shaped.

[0162] Fig.18 This is a cross-sectional view showing the structure of a brush 60B and a constant load spring 80B in a motor according to a second modification of the second embodiment. Fig.192 is a cross-sectional view showing the structure of a brush 60B and a constant load spring 80B in a motor according to a third variation of the second embodiment. The constant load spring 80B having a connecting portion 83B having a bent piece 84B bent in only one direction is shown in FIG. Fig.18 and Fig.19 As shown in FIG. 1 , it is suitable for a motor in which the brush 60B is arranged obliquely with respect to the axis of the rotating shaft 13. In this case, Fig.18 and Fig.19 As shown, it is preferable that the connection portion 83B of the constant load spring 80B is offset from the center in the height direction of the brush 60B.

[0163] Specifically, if Fig.18 As shown in FIG. 1 , when the front end of the brush 60B is tilted downward, it is preferable that the connecting portion 83B is offset upward relative to the center in the height direction of the brush 60B. Fig.18 As shown by the thick arrow, the load generated by the connection portion 83B can be directed obliquely downward. Therefore, even if the brush 60B is inclined, the brush 60B can be stably pressed against the commutator 14.

[0164] like Fig.19 As shown in FIG. 1 , when the front end of the brush 60B is tilted upward, it is preferable that the connecting portion 83B is offset downward relative to the center in the height direction of the brush 60B. Fig.19 As shown by the thick arrow, the load generated by the connection portion 83B can be directed obliquely upward. Therefore, even if the brush 60B is inclined, the brush 60B can be stably pressed against the commutator 14.

[0165] (Variation Example)

[0166] The technology of the present disclosure has been described above based on Embodiments 1 and 2. However, the technology of the present disclosure is not limited to Embodiments 1 and 2 described above.

[0167] For example, in the above-described first and second embodiments, the constant load spring 80 is disposed in a posture (horizontally disposed posture) in which the arrangement direction of the first spiral portion 81 and the second spiral portion 82 is parallel to the XY plane. Fig. 20 2C is a diagram showing an example of arrangement of a brush 60C and a constant load spring 80C in a motor 2C of a modified example. Fig. 20 As shown in the motor 2C, the constant load spring 80C is arranged in a posture (vertical posture) in which the arrangement direction of the first spiral portion 81 and the second spiral portion 82 is parallel to the Z-axis direction. Fig. 20 As in the brush 60C shown in FIG. 1 , a first brush 60a and a second brush 60b stacked in the Z-axis direction may be used. That is, a split brush may be used as the brush 60C.

[0168] In the above-mentioned first embodiment, the connecting portion 83 of the constant load spring 80 is integrally formed with the wire material constituting the first volute portion 81 and the second volute portion 82. However, this is not limited to this. For example, the connecting portion 83 of the constant load spring 80 may also be a connecting member independent of the wire material constituting the first volute portion 81 and the second volute portion 82. In this case, the connecting member as the connecting portion 83 may not be a strip-shaped wire material. This is also the same for the second embodiment.

[0169] In the above embodiment, the stator 20 is composed of the magnet 21. However, the present invention is not limited thereto. For example, the stator 20 may be composed of a stator core and a winding coil wound around the stator core.

[0170] In the above embodiment, the electric blower 1 is described as being used in an electric vacuum cleaner. However, the invention is not limited thereto. For example, the electric blower 1 may also be used in a hand dryer or the like.

[0171] In the above embodiment, an example in which the motor 2 is used in the electric blower 1 is described. However, the present invention is not limited to this, and the motor 2 may be used in electrical equipment other than the electric blower 1. The motor 2 is not limited to being used in household equipment. The motor 2 may also be used in industrial equipment.

[0172] In addition, various modifications that can be conceived by those skilled in the art to the above-described embodiments, or embodiments implemented by arbitrarily combining components and functions in the embodiments within the scope not departing from the gist of the present disclosure are also included in the present disclosure.

[0173] Industrial Applicability

[0174] The electric motor, electric blower, and the like of the present disclosure can be used in various electric appliances including electric vacuum cleaners and other household electric appliances.

[0175] Description of Reference Numerals

[0176] 1. Electric fan; 2. 2A, 2B, 2C, electric motor; 3. Rotating fan; 4. Air guide; 4a, main body; 4b, annular portion; 4c, connecting plate; 5. Fan housing; 5a, cover; 5b, side wall; 5c, air inlet; 10. Rotor; 11. Rotor core; 12. Winding coil; 13. Rotating shaft; 13a, first part; 13b, second part; 14. Commutator; 14a, commutator segment; 15, first bearing; 16, second bearing; 20. Stator; 21. Magnet; 30. Yoke; 40. Frame; 40a, opening; 40b, exhaust port; 41, bulging portion; 50 , bracket; 51, the first through hole; 52, the second through hole; 60, 60B, 60C, brush; 60a, the first brush; 60b, the second brush; 61, the front end face; 62, the rear end face; 63, the recess; 70, the brush holder; 71, the brush receiving portion; 72, the slit; 72a, the first slit; 72b, the second slit; 73, the protrusion; 80, 80A, 80B, 80C, the constant load spring; 81, the first scroll portion; 82, the second scroll portion; 83, 83A, 83B, the connecting portion; 84, 84B, the bending piece; 84a, the first bending piece; 84b, the second bending piece; 90, the braided line.

Claims

1. An electric motor, wherein: The motor has: A rotor having a rotating shaft extending along an axial direction; a commutator mounted on the rotating shaft; a brush in contact with the commutator; and a brush spring that presses the brush against the commutator, The brush spring comprises: a first volute portion and a second volute portion, each of which is formed of a strip-shaped plate material wound in a spiral shape; and a connecting portion, which connects the strip-shaped wire material forming the first volute portion and the strip-shaped wire material forming the second volute portion, The brush is pressed against the commutator by a load from the connection portion.

2. The electric motor according to claim 1, wherein: The brush has a front end surface in contact with the commutator and a rear end surface located on the opposite side to the front end surface. The connecting portion is in contact with a rear end surface of the brush.

3. The electric motor according to claim 2, wherein: The rear end surface of the brush abuts against an end surface of a belt-shaped wire material constituting the connecting portion.

4. The electric motor according to claim 2 or 3, wherein: A recess is formed on the rear end surface of the brush, At least a portion of the connection portion is inserted into the recess.

5. The electric motor according to any one of claims 1 to 3, wherein: The first scroll portion and the second scroll portion are arranged so as to sandwich the front end portion of the brush. The strip-shaped wire material constituting the first spiral portion is led out along one side surface of the brush. The belt-shaped wire material constituting the second spiral portion is led out along the other side surface of the brush.

6. The electric motor according to any one of claims 1 to 3, wherein: The motor further includes a brush holder having a brush receiving portion for receiving the brush. Slits extending along the length direction of the brush are formed on both side surfaces of the brush housing. The connecting portion protrudes from the slit.

7. The electric motor according to claim 6, wherein: The first spiral portion and the second spiral portion are arranged so as to sandwich the brush housing portion.

8. The electric motor according to claim 6, wherein: The first scroll portion and the second scroll portion are fixed to the brush holder.

9. The electric motor according to claim 2 or 3, wherein: The connecting portion has a bent piece formed by partially bending a strip-shaped wire material constituting the connecting portion. The bent piece is in surface contact with the rear end surface of the brush.

10. The electric motor according to claim 9, wherein There are multiple bending pieces. The plurality of bent pieces include a first bent piece and a second bent piece bent in opposite directions to each other in a height direction of the brush.

11. The electric motor according to claim 9, wherein: The bent piece is formed by bending the connecting portion in only one direction.

12. The electric motor according to claim 11, wherein The connecting portion is offset from the center of the brush in a height direction.

13. The electric motor according to claims 1 to 3, wherein: The strip-shaped wire material constituting the first spiral portion, the strip-shaped wire material constituting the second spiral portion, and the strip-shaped wire material constituting the connecting portion are integrated.

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