Electric motors and electric fans

Abstract

The electric motor (2) includes: a rotor (10) having a shaft (13) and a commutator (14) mounted on the shaft (13); a brush (60) having a first end in contact with the commutator (14) and a second end located on the side opposite to the first end; a brush holder (70) for holding the brush (60); and a constant load spring (80) for pressing the brush (60) against the commutator (14), the constant load spring (80) including a spiral portion (81) in contact with the second end of the brush (60) and an outer end (82) fixed to the brush holder (70).

Description

Technical Field

[0001] The present disclosure relates to an electric motor and an electric blower. Background Art

[0002] As the electric motors installed in household electric vacuum cleaners, there are commutator motors with brushes (commutator motors) or brushless motors without brushes. Among them, since brushless motors require electronic components and drive circuits for driving, the motor as a whole becomes expensive. Therefore, in electric vacuum cleaners, research has been conducted to use commutator motors with brushes, which are cheaper than brushless motors, to improve performance.

[0003] In a commutator motor, a brush spring is used to press a brush against a commutator. The brush spring presses the brush by utilizing spring elasticity. Conventionally, a coil spring or a torsion spring is used as a brush spring of a commutator motor.

[0004] However, in a coil spring or a torsion spring, since the difference between the pressing force (initial force) before the brush wears out and the pressing force (final force) after the brush wears out is large, the initial force needs to be set high to ensure a final force above a certain level. Therefore, in the initial stage, the friction between the brush and the commutator increases when the rotor rotates, and the sliding loss of the brush increases. As a result, the efficiency of the motor decreases and the life of the brush decreases.

[0005] Therefore, conventionally, a technique has been proposed in which a constant load spring is used as a brush spring to reduce the difference between the initial pressure and the final pressure and apply a uniform pressure (load) to the brush (for example, Patent Document 1).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: CD-ROM of Japanese Utility Model Application No. 03-077375 (Japanese Utility Model Application Publication No. 05-029268) Summary of the invention

[0009] Problem that the invention aims to solve

[0010] However, the brush spring disclosed in Patent Document 1 requires two fixing locations for fixing the brush spring, so there is a problem that the brush spring cannot be easily fixed.

[0011] The present disclosure has been made to solve such a problem, and an object of the present disclosure is to provide a motor, an electric blower, etc., which can easily fix a constant load spring even when the constant load spring is used as a brush spring.

[0012] Solutions for solving problems

[0013] In order to achieve the above-mentioned purpose, a technical solution of the electric motor disclosed in the present invention includes: a rotor, which has an axis extending along an axial direction and a commutator mounted on the axis; a brush, which includes a first end in contact with the commutator and a second end located on the side opposite to the first end in a radial direction intersecting the axial direction; a brush holder, which holds the brush in a manner such that the brush moves along the radial direction; and a constant load spring, which is used to press the brush against the commutator, the constant load spring including a spiral portion in contact with the second end included in the brush and an outer end fixed to the brush holder.

[0014] In addition, a technical solution of the electric blower disclosed in the present invention includes: the above-mentioned electric motor; and a rotary fan mounted on the shaft provided in the electric motor.

[0015] Effects of the Invention

[0016] Even when a constant load spring is used as the brush spring, the constant load spring can be easily fixed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a perspective view of the electric blower according to the embodiment as seen from above.

[0018] Figure 2 This is a perspective view of the electric blower according to the embodiment as seen from below.

[0019] Figure 3 It is an exploded perspective view of the electric blower according to the embodiment.

[0020] Figure 4 It is a cross-sectional view of the electric blower according to the embodiment.

[0021] Figure 5 It is a cross-sectional view of the electric blower according to the embodiment.

[0022] Figure 6 This is a cross-sectional view of the electric blower according to the embodiment when cut along a plane that passes through a pair of brushes and is perpendicular to the axis of the shaft.

[0023] Figure 7 This is a perspective view of a brush holder housing a brush, a constant load spring, and a conductive wire as viewed from the front.

[0024] Figure 8 This is a perspective view of a brush holder housing a brush, a constant load spring, and a conductive wire as viewed from the rear.

[0025] Fig. 9This is an exploded perspective view of the brush, brush holder, constant load spring, conductive wire, and electrode terminal.

[0026] Fig. 10A This is an enlarged perspective view of the front portion of the brush holder in a state where the brushes and the constant load spring are accommodated.

[0027] Fig. 10B This is a cross-sectional perspective view of the front portion of the brush holder in a state where the brushes and the constant load spring are accommodated.

[0028] Fig.11 This is a cross-sectional perspective view of the brush and surrounding portion of the electric blower according to the embodiment when the portion is cut along a plane that passes through a pair of brushes and is perpendicular to the axis of the shaft.

[0029] Fig.12 This is a diagram for explaining a situation when a constant load spring is accommodated in a brush holder.

[0030] Fig.13 It is a diagram for explaining a state when a brush is worn in the electric blower according to the embodiment.

[0031] Fig.14 It is a diagram for explaining the length of the conductive wire connected to the brush of the electric blower according to the embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, the 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, shapes, materials, constituent elements, configuration positions and connection forms of the constituent elements 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 are described as arbitrary constituent elements.

[0033] In addition, in this specification and the drawings, the X-axis, the Y-axis, and the Z-axis represent three axes of a three-dimensional orthogonal coordinate system. The X-axis and the Y-axis are axes that are orthogonal to each other and are also orthogonal to the Z-axis.

[0034] In addition, each figure is a schematic diagram and does not necessarily illustrate the figure strictly. In addition, in each figure, the same reference numerals are given to substantially the same structure, and repeated descriptions are omitted or simplified. In this embodiment, the Z-axis direction is the direction of the axis C of the shaft 13.

[0035] (Implementation Method)

[0036] First, use Figure 1 to Figure 5 , the overall structure of electric blower 1 according to the embodiment will be described. Figure 1 This is a perspective view of the electric blower 1 according to the embodiment as viewed from above. Figure 2This is a perspective view of the electric blower 1 as seen from below. Figure 3 It is an exploded perspective view of the electric blower 1 . Figure 4 and Figure 5 This is a cross-sectional view of the electric blower 1 cut along a plane passing through the axis C of the shaft 13 . Figure 4 The cross section (XZ cross section) is taken through a pair of brushes 60. Figure 5 This is a cross-sectional view (YZ cross section) taken along a cross section of a pair of magnets 21 of the stator 20. Figure 4 and Figure 5 In the figure, only the cross section is shown. Figure 4 and Figure 5 Arrows are used to indicate the flow of air.

[0037] like Figure 1 to Figure 5 As shown, the electric blower 1 includes a motor 2 having a rotor 10 and a stator 20, a rotary fan 3 mounted on a shaft 13 of the motor 2, an air guide 4 into which air exhausted from the rotary fan 3 flows, and a fan cover 5 that accommodates the rotary fan 3. The electric blower 1 can be used in, for example, an electric vacuum cleaner.

[0038] 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. In the present embodiment, the motor 2 is a commutator motor with a brush.

[0039] Specifically, if Figure 3 to Figure 5 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. The rotor 10, the stator 20, and the yoke 30 are arranged in the frame 40. In addition, the detailed structure of each component of the motor 2 will be described later.

[0040] The rotary fan 3 sucks air into a housing composed of a frame 40 and a fan cover 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, and air is sucked in from the air inlet 5c of the fan cover 5, and the 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.

[0041] As an example, the rotary fan 3 includes a first side plate having 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 plate-shaped and curved into arc shapes and are arranged radially.

[0042] The air guide 4 has a function of forming a flow path of air flow. For example, the air guide 4 straightens and discharges the air sucked from the air inlet 5c of the fan cover 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, in the present embodiment, 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.

[0043] 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.

[0044] The main body 4a is a circular plate having a through hole for fixing to the center portion 51 of 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 cover 5 in the direction of the axis C (thrust direction) of the shaft 13. The plurality of connecting plates 4c function as guide plates for forming a flow path for the airflow. Specifically, the plurality of connecting plates 4c are plate shapes bent into an arc shape, and are radially arranged in a spiral manner from the through hole of the main body 4a toward the outside. The air guide 4 is made of, for example, a resin material, but may also be made of a metal material.

[0045] The fan cover 5 is a housing that accommodates the rotary fan 3. In the present embodiment, the fan cover 5 is a cover that covers the rotary fan 3 and the air guide 4. As an example, the fan cover 5 is a metal cover made of a metal material, but may be a resin cover made of a resin material.

[0046] The fan cover 5 includes a cover portion 5a covering the upper portion of the rotary fan 3 and the air guide 4, and a side wall portion 5b covering the side portion of the rotary fan 3 and the air guide 4. In addition, the fan cover 5 includes an air intake port 5c (intake port) for taking in external air. In the present embodiment, the air intake port 5c is a circular through hole provided in the center of the cover portion 5a.

[0047] The fan cover 5 is fixed to the bracket 50. In the present embodiment, the fan cover 5 is fixed to the bracket 50 via the air guide 4. In addition, a fan cover spacer having an opening corresponding to the air intake port 5c may be attached to the air intake port 5c of the fan cover 5.

[0048] In the electric blower 1 configured as described above, when the rotor 10 of the motor 2 rotates, the rotary fan 3 rotates, and air is sucked into the fan cover 5 from the air inlet 5c of the fan cover 5. As a result, air flows into the rotary fan 3, and the air sucked into the rotary fan 3 is compressed to high pressure by the fan blades of the rotary fan 3, and 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 5b of the fan cover 5, and reaches the bracket 50 through the ventilation path of the air guide 4.

[0049] Part of the air reaching the bracket 50 flows into the inside of the frame 40 through the bracket 50, passes through the inside of the frame 40, and is discharged to the outside from the exhaust port 40b of the frame 40. In other words, the air flowing into the inside of the frame 40 cools the heat generating components (windings, etc.) of the motor 2 while being discharged to the outside of the electric blower 1.

[0050] On the other hand, another part of the air reaching bracket 50 is directly discharged to the outside of electric blower 1 through bracket 50 without passing through the inside of frame 40. Thus, the airflow can be discharged to the outside of electric blower 1 without causing loss due to passing through the inside of frame 40.

[0051] Next, refer to Figure 3 to Figure 5 , the detailed structure of each component included in the motor 2 is described.

[0052] like Figure 4 and Figure 5 As shown, the rotor 10 is arranged inside the stator 20 with a small air gap therebetween. The rotor 10 rotates around the axis C of the shaft 13. The rotor 10 rotates at a high speed of, for example, 50,000 rpm.

[0053] The rotor 10 of the present embodiment is an inner rotor, and is disposed inside the stator 20. Specifically, the rotor 10 is surrounded by the stator 20 with a small air gap therebetween.

[0054] As an example, the rotor 10 is an armature, and includes a rotor core 11 (rotor core) and a winding coil 12 wound around the rotor core 11 via an insulator. In addition, the rotor 10 also includes a shaft 13 and a commutator 14. Figure 3 to Figure 5 In FIG. 1 , the winding coil 12 is schematically shown.

[0055] The rotor core 11 is a laminated body formed by laminating a plurality of electromagnetic steel sheets along the direction in which the axis C of the shaft 13 extends (the direction of the rotation axis). The rotor core 11 has a plurality of teeth. When current flows through the winding coil 12, the rotor core 11 (rotor 10) generates a magnetic force acting on the stator 20.

[0056] The shaft 13 is a rotating shaft when the rotor 10 rotates, and extends in the direction of the axis C, that is, in the longitudinal direction. The shaft 13 is fixed to the center of the rotor 10. The shaft 13 is, for example, a metal rod, and is fixed to the rotor core 11 in a state of penetrating the rotor core 11. For example, the shaft 13 is fixed to the rotor core 11 by being pressed into or shrink-fitted into the center hole of the rotor core 11.

[0057] The first portion 13a of the shaft 13 protruding from the rotor core 11 to one side is supported by the first bearing portion 15. On the other hand, the second portion 13b of the shaft 13 protruding from the rotor core 11 to the other side is supported by the second bearing portion 16. As an example, the first bearing portion 15 and the second bearing portion 16 are bearings that support the shaft 13. In this way, the shaft 13 is held by the first bearing portion 15 and the second bearing portion 16 in a rotatable state. In addition, the first bearing portion 15 is fixed to the bracket 50, and the second bearing portion 16 is fixed to the bottom of the frame 40. That is, the bracket 50 is the first bracket, and the frame 40 is the second bracket.

[0058] In the present embodiment, the first portion 13a of the shaft 13 protrudes from the first bearing portion 15. At the tip end portion of the first portion 13a of the shaft 13 protruding from the first bearing portion 15, the rotary fan 3 is attached.

[0059] The commutator 14 is mounted on the shaft 13. Therefore, the commutator 14 rotates together with the shaft 13. In the present embodiment, the commutator 14 is mounted on the second portion 13b of the shaft 13. That is, the commutator 14 is arranged at a position on the side of the shaft 13 opposite to the rotating fan 3 side. Specifically, the commutator 14 is arranged at a position between the rotor core 11 and the second bearing portion 16 of the shaft 13.

[0060] The commutator 14 is composed of a plurality of segments 14a arranged in an annular shape so as to surround the shaft 13. The plurality of segments 14a are insulated and separated from each other in the rotation direction of the shaft 13. The plurality of segments 14a are electrically connected to the winding coil 12, respectively.

[0061] The rotor 10 configured in this manner rotates due to interaction between magnetic flux generated in the rotor core 11 (rotor 10 ) and magnetic flux generated in the stator 20 .

[0062] like Figure 5 As shown, the stator 20 is opposite to the rotor 10. Specifically, the stator 20 is opposite to the rotor core 11 and is arranged on the radial outer peripheral side of the rotor core 11. In this embodiment, the stator 20 has a plurality of magnets 21 arranged at intervals from each other in the circumferential direction of the rotor 10. The magnet 21 is a field magnet that forms a magnetic flux for generating torque, for example, a permanent magnet having an S pole and an N pole. The plurality of magnets 21 are each in an arc shape with a substantially constant thickness when viewed from above.

[0063] In the present embodiment, the stator 20 is composed of 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.

[0064] like Figure 5 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, and 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. Specifically, the yoke 30 is made of an iron plate.

[0065] like Figure 3 As shown, in the present embodiment, the yoke 30 is a cylindrical body whose outer and inner peripheral shapes are substantially oblong (racetrack-shaped) when viewed from above, and has an arc portion 31 and a straight portion 32. Thus, by providing the straight portion 32 in the yoke 30, the cross-sectional shape of the yoke 30 is set to be substantially oblong, thereby shortening the magnetic path compared to a yoke having a circular cross-sectional shape (i.e., a cylindrical yoke), and suppressing the loss at the yoke 30 (magnetic path).

[0066] A pair of magnets 21 are arranged inside the arc portion 31 of the yoke 30 . Specifically, each of the pair of magnets 21 has a shape along the inner peripheral surface of the arc portion 31 , and is arranged so that the outer peripheral surface of the magnet 21 and the inner peripheral surface of the arc portion 31 are in close contact.

[0067] like Figure 1 to Figure 3 As shown, the frame 40 is a case that accommodates the components constituting the motor 2, such as the rotor 10 and the stator 20. In the present embodiment, the frame 40 is an outer member (housing) of the electric blower 1 and the motor 2. The frame 40 is a bottomed cylindrical body having an opening 40a. The yoke 30 accommodated in the frame 40 and the frame 40 are separate components. Thus, the frame 40 and the yoke 30 can be formed of different materials. Specifically, the frame 40 can be formed of a non-magnetic material, compared to the yoke 30 formed of a magnetic material. Therefore, the frame 40 can be formed of a light and strong metal material. In the present embodiment, the frame 40 is made of aluminum.

[0068] In addition, if Figure 1 to Figure 5 As shown, a plurality of exhaust ports 40b are respectively formed on the side wall and the bottom of the frame 40, and the plurality of exhaust ports 40b are used to discharge the air sucked by the rotation of the rotary fan 3. For example, a pair of exhaust ports 40b facing each other are formed on the side wall of the frame 40, and a pair of exhaust ports 40b facing each other are formed on the bottom of the frame 40.

[0069] In addition, if Figure 4 and Figure 5As shown, a gap G serving as a ventilation path in the direction of the axis C (rotation axis direction) of the shaft 13 is formed between the outer surface of the yoke 30 and the inner surface of the frame 40. In the present embodiment, a plurality of gaps G are formed.

[0070] like Figure 1 to Figure 3 As shown, the frame 40 has a bulging portion 41 that bulges outward in the radial direction (i.e., radially outward with the axis C as the center) of a part of the side wall portion of the frame 40. The gap G is a spatial region between the bulging portion 41 and the yoke 30. In addition, the bulging portion 41 extends in the direction in which the axis C of the shaft 13 extends (the direction of the rotation axis). Therefore, the gap G also extends in the direction in which the axis C of the shaft 13 extends. In addition, the bulging portion 41 extends in the rotation direction of the shaft 13 (rotation axis). Specifically, the bulging portion 41 extends in an arc shape along the rotation direction of the shaft 13. As an example, the bulging portion 41 is a rib formed as a protrusion, for example, it can be formed by stamping the side wall portion of the frame 40.

[0071] like Figure 4 and Figure 5 As shown, the bracket 50 covers the opening 40a of the frame 40. In this embodiment, the bracket 50 does not completely block the opening 40a of the frame 40, but partially covers the opening 40a of the frame 40. That is, when the bracket 50 is mounted on the frame 40, the air rectified by the air guide 4 flows into the frame 40.

[0072] Specifically, the bracket 50 is provided with a plurality of through holes as openings through which the air rectified by the air guide 4 passes. Figure 3 to Figure 5 As shown, in the present embodiment, the bracket 50 is provided with an inner through hole 50a which is a first through hole located radially inside, and an outer through hole 50b which is a second through hole located radially outside of the inner through hole 50a.

[0073] In addition, the bracket 50 has a center portion 51 which is a portion including the center of the bracket 50, an inner ring portion 52 which is a first ring portion in an annular shape and is located radially outward from the center portion 51 and surrounds the center portion 51, and an outer ring portion 53 which is a second ring portion and is located radially outward from the inner ring portion 52 and surrounds the inner ring portion 52.

[0074] Furthermore, the bracket 50 has a first bridge portion, namely an inner bridge portion 54 (first bridge portion), which is located radially inward, and a second bridge portion, namely an outer bridge portion 55, which is located radially outward from the inner bridge portion 54. The inner bridge portion 54 separates two inner through holes 50a adjacent to each other in the rotation direction of the shaft 13, and crosses the center portion 51 and the inner annular portion 52. That is, the inner bridge portion 54 connects the center portion 51 and the inner annular portion 52 in a bridging manner. The outer bridge portion 55 separates two outer through holes 50b adjacent to each other in the rotation direction of the shaft 13, and crosses the inner annular portion 52 and the outer annular portion 53. That is, the outer bridge portion 55 connects the inner annular portion 52 and the outer annular portion 53 in a bridging manner.

[0075] The bracket 50 thus configured is fixed to the frame 40. For example, the bracket 50 and the frame 40 are fixed by engaging the bracket 50 with a portion (recess) between two adjacent bulging portions 41 in the side wall portion of the frame 40. As an example, the bracket 50 and the frame 40 can be fixed by riveting the bracket 50 and the frame 40.

[0076] Next, refer to Figure 3 and Figure 4 and use Figure 6 to Figure 9 The brush 60 , the brush holder 70 , and the constant load spring 80 will be described. Figure 6 It is a cross-sectional view (XY cross-sectional view) of the electric blower 1 when cut along a plane passing through the pair of brushes 60 and perpendicular to the axis C of the shaft 13 . Figure 7 and Figure 8 It is a perspective view of the brush holder 70 in a state where the brush 60 , the constant load spring 80 , and the conductive wire 91 are accommodated. Figure 7 This is a stereogram when viewed from the front. Figure 8 This is a stereoscopic view when viewed from the rear. Fig. 9 It is an exploded perspective view of the brush 60 , the brush holder 70 , the constant load spring 80 , the conductive wire 91 , and the electrode terminal 92 .

[0077] like Figure 4 As shown, the brush 60 contacts the commutator 14 in a radial direction intersecting the direction of the axis C. The brush 60 is pressed against the commutator 14 by a pressing force from a constant load spring 80. Specifically, the brush 60 is configured to be movable in a radial direction with the shaft 13 as the rotation center and to be in sliding contact with the commutator 14 under the action of the pressing force from the constant load spring 80.

[0078] like Figure 6As shown, a pair of brushes 60 are provided. The pair of brushes 60 are arranged relative to each other in a manner of clamping the commutator 14. That is, the pair of brushes 60 are arranged relative to each other with the commutator 14 sandwiched therebetween. In the present embodiment, the pair of brushes 60 are axially symmetrical with the axis C of the shaft 13 as the center. The pair of brushes 60 are respectively longitudinally elongated members, and are arranged in a manner such that the length direction thereof becomes the radial direction of the rotation of the shaft 13. As an example, the brush 60 is a longitudinally elongated substantially rectangular parallelepiped.

[0079] The brush 60 is a power supply brush that supplies power to the rotor 10 by contacting the commutator 14. Specifically, the brush 60 contacts the commutator segments 14a of the commutator 14, so that the armature current supplied to the brush 60 flows to the winding coil 12 of the rotor 10 via the commutator segments 14a. The brush 60 is made of a conductive material. As an example, the brush 60 is a conductive carbon brush made of carbon.

[0080] like Figure 4 and Figure 6 As shown, the brush 60 includes a front end portion 61 which is a first end portion in contact with the commutator 14 and a rear end portion 62 which is a second end portion located on the opposite side to the front end portion 61 .

[0081] The tip portion 61 of the brush 60 is one end in the longitudinal direction of the brush 60 and is the tip end of the brush 60 on the shaft 13 side (inner side). The tip portion 61 has a tip surface 61a which is in contact with the commutator segment 14a of the commutator 14.

[0082] On the other hand, the rear end portion 62 of the brush 60 is the other end in the longitudinal direction of the brush 60 and is the tip portion of the brush 60 on the side opposite to the shaft 13 side (outer side). The rear end portion 62 has a rear end surface 62a which is a contact surface with the constant load spring 80.

[0083] like Figure 4 As shown, the brush 60 is held by the brush holder 70 in a manner of radial movement intersecting the direction of the axis C. That is, the brush holder 70 is a holder for holding the brush 60. The brush holder 70 is fixed to the frame 40. Specifically, the brush holder 70 is inserted into an opening provided in the frame 40 and is fixed to the frame 40 by screws 100. The brush holder 70 is arranged in accordance with the number of the brushes 60. In the present embodiment, since two brushes 60 are arranged, two brush holders 70 are also arranged.

[0084] like Figure 7 and Figure 8As shown, the brush holder 70 accommodates the brush 60. Specifically, the brush holder 70 has a through hole 71, and the brush 60 is inserted into the through hole 71. The brush holder 70 is made of, for example, an insulating resin material. In the present embodiment, the brush holder 70 is a resin molded product formed by integral molding using a resin material.

[0085] Furthermore, the brush holder 70 has a housing portion 72 for housing the conductive wire 91. The housing portion 72 is a recess (space) provided in the brush holder 70. The conductive wire 91 housed in the housing portion 72 is covered by the insulating brush holder 70. This can suppress insulation failure between the conductive wire 91 and surrounding components.

[0086] The conductive wire 91 is, for example, a pigtail wire, such as Figure 8 and Fig. 9 As shown, one end portion of the conductive wire 91 is connected to the brush 60, and the other end portion is connected to the electrode terminal 92. The conductive wire 91 is configured so as not to exist on the movement path of the brush 60 sliding. Specifically, one end portion of the conductive wire 91 is connected to the side surface of the brush 60, and the conductive wire 91 is wound in a manner that does not interfere with the brush 60 even when the brush 60 is worn due to sliding. Thus, it is possible to suppress the situation where the conductive wire 91 hinders the sliding of the brush 60. In addition, in the present embodiment, even if the brush 60 moves due to wear, the connection position of the conductive wire 91 and the brush 60 is always located in front of the contact position between the brush 60 and the constant load spring 80 and in the rear of the fixed position between the brush holder 70 and the constant load spring 80.

[0087] The length of the conductive wire 91 is set to be long in consideration of the movement of the brush 60 due to wear, but the housing portion 72 has a structure for housing the conductive wire 91 in such a manner that the conductive wire 91 does not protrude from the brush holder 70 even in a state before the brush 60 is worn. That is, the conductive wire 91 is continuously housed in the housing portion 72 in such a manner that the conductive wire 91 does not protrude from the housing portion 72 even if the brush 60 moves due to wear. Thus, even when the conductive wire 91 is loose in the initial stage before the brush 60 is worn, poor insulation between the conductive wire 91 and the surrounding components can be suppressed.

[0088] like Figure 8 and Fig. 9As shown, the electrode terminal 92 connected to the conductive wire 91 is a power supply terminal that receives power to be energized to the winding coil 12 of the rotor 10. That is, the electrode terminal 92 supplies power to the brush 60. The power supplied to the electrode terminal 92 is supplied to the brush 60 via the conductive wire 91 and to the winding coil 12 of the rotor 10 via the commutator segment 14a. In the present embodiment, the electrode terminal 92 is fixed to the brush holder 70. In addition, the electrode terminal 92 is fixed to the brush holder 70 in a manner that does not exist on the movement path of the brush 60 sliding in the radial direction. As a result, compared with the case where the electrode terminal 92 exists on the movement path of the brush 60, the brush 60 can be extended, and therefore the life of the motor 2 can be extended.

[0089] In addition, if Figure 6 As shown, the brush holder 70 accommodates the constant load spring 80. That is, the brush holder 70 not only holds the brush 60 but also holds the constant load spring 80. In the present embodiment, the constant load spring 80 is accommodated in the through hole 71. The constant load spring 80 is arranged according to the number of the brushes 60. In the present embodiment, since two brushes 60 are arranged, two constant load springs 80 are also arranged.

[0090] The constant load spring 80 is a brush spring for pressing the brush 60 against the commutator 14. Specifically, the constant load spring 80 presses the brush 60 against the commutator 14 by applying pressure to the brush 60. The constant load spring 80 is a spring that applies uniform pressure (load) to the brush 60. In the present embodiment, the constant load spring 80 is a coil spring having a portion in which a wire is wound in a spiral shape. The constant load spring 80 is, for example, a spring spring made of a strip-shaped wire made of a metal material or the like.

[0091] like Figure 6 and Fig. 9 As shown in the figure, the constant load spring 80 has a portion formed by winding a strip-shaped wire, namely a spiral portion 81. Specifically, the spiral portion 81 is a portion formed by winding a strip-shaped metal plate in a longitudinal shape only in one direction. In addition, the constant load spring 80 has an outer end portion 82, which is one end of the strip-shaped metal plate, and an inner end portion 83, which is the other end of the strip-shaped metal plate. The outer end portion 82 is the top end portion of the outer peripheral side of the strip-shaped metal plate drawn out from the spiral portion 81, and the inner end portion 83 is the top end portion of the inner peripheral side of the strip-shaped metal plate located inside the spiral portion 81.

[0092] The constant load spring 80 presses the brush 60 against the commutator 14 using the coil 81. Specifically, the coil 81 of the constant load spring 80 contacts the rear end 62 of the brush 60, and the brush 60 is urged toward the commutator 14 by applying pressure (spring pressure) to the brush 60 using the spring elastic force (spring restoring force) of the coil 81.

[0093] As mentioned above, Figure 6 As shown, the constant load spring 80 is accommodated in the brush holder 70. Specifically, the constant load spring 80 is arranged in the through hole 71 of the brush holder 70 in such a manner that the coil portion 81 is located behind the rear end portion 62 of the brush 60. In addition, the outer end portion 82 of the constant load spring 80 is arranged in the through hole 71 of the brush holder 70 in such a manner that it passes through the side of the brush 60 and is led toward the commutator 14.

[0094] In addition, the constant load spring 80 is fixed to the brush holder 70. Specifically, the outer end 82 of the constant load spring 80 is fixed to the brush holder 70. In the present embodiment, the constant load spring 80 is fixed to the brush holder 70 by the outer end 82 of the constant load spring 80 being locked to the brush holder 70. Specifically, as Fig. 10A , Fig. 10B , Fig.11 As shown in the figure, a notch-shaped recessed portion 82a is provided as a first locking portion at an outer end portion 82 included in the constant load spring 80, and a convex portion 70a is provided as a second locking portion at the brush holder 70. With this structure, the constant load spring 80 is fixed to the brush holder 70 because the recessed portion 82a formed on the constant load spring 80 and the convex portion 70a formed on the brush holder 70 are locked.

[0095] In addition, in the present embodiment, the constant load spring 80 is fixed to the brush holder 70 only at the outer end 82, and the constant load spring 80 is not fixed at the portion other than the outer end 82. In other words, the portion other than the outer end 82 of the constant load spring 80 is not supported but is free. In other words, the constant load spring 80 is supported only at the outer end 82.

[0096] In addition, if Figure 7 and Fig. 9 As shown in FIG. 1 , the brush holder 70 is provided with an opening 73 through which the coil 81 of the constant load spring 80 can pass. The opening 73 is a through hole provided on the side of the brush holder 70, and communicates with the through hole 71 in which the brush 60 is arranged. In addition, the opening 73 has, for example, a rectangular opening and extends along the longitudinal direction of the brush 60. In this way, by providing the opening 73 in the brush holder 70, the constant load spring 80 can be easily arranged in the brush holder 70.

[0097] Specifically, when the constant load spring 80 is assembled in the brush holder 70, as shown in FIG. Fig.12 As shown in the figure, the concave portion 82a and the convex portion 70a are locked by inserting the spiral portion 81 of the constant load spring 80 from the opening 73 into the inside of the brush holder 70, and hooking the concave portion 82a of the constant load spring 80 on the convex portion 70a of the brush holder 70. Thus, the constant load spring 80 can be arranged in the brush holder 70 in a state where the outer end portion 82 is fixed to the brush holder 70.

[0098] In the motor 2 configured as described above, the armature current supplied to the brush 60 flows to the winding coil 12 of the rotor 10 via the commutator 14. As a result, a magnetic flux is generated in the rotor 10, and the magnetic force generated by the interaction between the magnetic flux of the rotor 10 and the magnetic flux generated by the magnet 21 of the stator 20 becomes a torque that rotates the rotor 10, and the rotor 10 rotates. Then, the shaft 13 rotates due to the rotation of the rotor 10, and the rotary fan 3 mounted on the shaft 13 rotates.

[0099] Thus, when the rotor 10 rotates, the tip 61 of the brush 60 in contact with the commutator 14 wears. At this time, the brush 60 is always pressed against the commutator 14 by a constant pressing force (load) from the constant load spring 80. Fig.13 As shown in FIG. 1 , the front end portion 61 of the brush 60 gradually wears due to friction with the commutator segment 14a, and slides toward the commutator 14 in the through hole 71 of the brush holder 70. At this time, the wire material constituting the constant load spring 80 gradually winds as the brush 60 becomes shorter due to wear. That is, the spiral portion 81 gradually approaches the outer end portion 82.

[0100] In addition, in this embodiment, if Fig.14 As shown, the length of the conductive wire 91 is set so that the constant load spring 80 applies a pressing force to the brush 60 even when the brush 60 is worn to the maximum extent. In addition, the length of the conductive wire 91 is set so that the brush 60 is arranged at a position that receives the load of the constant load spring 80 from the initial position of the constant load spring 80 before the brush 60 is assembled.

[0101] According to this structure, even when the brush 60 is completely worn, the conductive wire 91 protrudes. That is, if this structure is used, since the brush 60 is made to slide as desired, even if there is a gap between the brush 60 and the brush holder 70, the vibration of the brush 60 can be suppressed. Therefore, the motor 2 of this embodiment can suppress the adverse phenomenon caused by the vibration of the brush 60. Specifically, sometimes the brush 60 jumps up and temporarily separates from the commutator 14 due to the vibration of the brush 60. If the brush 60 is temporarily separated from the commutator 14, the current flowing from the brush 60 to the commutator 14 is blocked, so that adverse phenomena such as sparks occur. However, if this structure is used, the movement of the brush 60 can be stabilized. That is, the conductive wire 91 of this embodiment has both the function of supplying power to the brush 60 and the function of stably holding the brush 60.

[0102] Furthermore, if the length of the conductive wire 91 is set as described above, the constant load spring 80 can always apply pretension to the brush 60 by utilizing the elasticity of the constant load spring 80. Thus, a reaction force from the brush 60 is applied to the constant load spring 80, and thus the constant load spring 80 can be prevented from being separated from the brush holder 70. In addition, if this structure is set, the constant load spring 80 can be prevented from being separated not only when the motor 2 is driven, but also when the motor 2 is assembled. That is, the motor 2 of this embodiment can prevent the constant load spring 80 from being separated from the motor 2 when the motor 2 is assembled until the life of the brush 60.

[0103] As described above, according to the motor 2 and the electric blower 1 of the present embodiment, the constant load spring 80 is used as the brush spring for pressing the brush 60 against the commutator 14. As a result, a constant load can be applied to the brush 60, so the initial pressure of the brush spring can be set to be small. Therefore, it is possible to suppress the friction between the brush 60 and the commutator 14 from increasing and the sliding loss of the brush 60 from increasing in the initial stage, so if the motor 2 of the present embodiment is used, it is possible to suppress the reduction in efficiency or life of the motor 2.

[0104] Furthermore, according to the motor 2 and the electric blower 1 of the present embodiment, the constant load spring 80 used as the brush spring has the spiral portion 81 in contact with the rear end portion 62 (second end portion) of the brush 60 and the outer end portion 82 fixed to the brush holder 70. Thus, the constant load spring 80 can be supported only at one portion, the outer end portion 82. Thus, even when the constant load spring 80 is used as the brush spring, the constant load spring 80 can be easily fixed to the brush holder 70.

[0105] Furthermore, in the present embodiment, the constant load spring 80 is fixed to the brush holder 70 by the outer end portion 82 of the constant load spring 80 being locked to the brush holder 70 .

[0106] Thereby, the constant load spring 80 can be easily fixed to the brush holder 70 .

[0107] Specifically, a notch-shaped recessed portion 82 a is provided at the outer end portion 82 of the constant load spring 80 , and a protruding portion 70 a to which the recessed portion 82 a is engaged is provided at the brush holder 70 .

[0108] Thus, the concave portion 82 a of the constant load spring 80 and the convex portion 70 a of the brush holder 70 are locked in an engaging manner, so that the constant load spring 80 can be fixed to the brush holder 70 .

[0109] (Variation Example)

[0110] As mentioned above, although the electric motor 2 and the electric blower 1 of this disclosure were demonstrated based on embodiment, this disclosure is not limited to the said embodiment.

[0111] For example, in the above-mentioned embodiment, as an example of a locking structure for locking and fixing the brush holder 70 and the constant load spring 80, the convex portion 70a is provided on the brush holder 70, and the notch-shaped concave portion 82a is provided on the outer end portion 82 of the constant load spring 80, but the present invention is not limited thereto. For example, a concave portion may be provided on the brush holder 70, and a convex portion may be provided on the outer end portion 82 of the constant load spring 80, and the outer end portion 82 of the constant load spring 80 may be fixed to the brush holder 70 by locking these concave portions and convex portions.

[0112] In addition, a locking structure in which a through hole and a protrusion are locked instead of a locking structure in which a notch-shaped recess and a protrusion are locked may be used. For example, a protrusion may be provided on the side surface of the brush holder 70, and a through hole may be provided on the outer end 82 of the constant load spring 80, and the outer end 82 of the constant load spring 80 may be fixed to the brush holder 70 by locking the protrusion of the brush holder 70 in the through hole of the constant load spring 80.

[0113] Furthermore, the method of fixing the constant load spring 80 and the brush holder 70 is not limited to the locking structure, and the brush holder 70 and the outer end portion 82 of the constant load spring 80 may be fixed by a method other than the locking structure.

[0114] In addition, in the above embodiment, the stator 20 is composed of the magnet 21, but it is not limited to this. For example, the stator 20 can also be composed of a stator core and a winding coil wound on the stator core. In addition, in this case, since the yoke part is formed on the stator core, the yoke 30 functions as an auxiliary yoke.

[0115] Furthermore, in the above-mentioned embodiment, the case where the electric blower 1 is used in an electric vacuum cleaner is described, but the invention is not limited thereto. For example, the electric blower 1 may also be used in a hand dryer or the like.

[0116] In the above embodiment, the motor 2 is used for the electric blower 1, but the motor 2 is not limited to this and can be used for electrical equipment other than the electric blower 1. In addition, the motor 2 is not limited to the case of being used for household equipment and can be used for industrial equipment such as automotive equipment.

[0117] In addition, various modifications that can be conceived by those skilled in the art to the above-mentioned embodiments and embodiments achieved by arbitrarily combining the components and functions of the embodiments within the scope not departing from the gist of the present disclosure are also included in the present disclosure.

[0118] Industrial Applicability

[0119] The electric motor and the electric blower disclosed in the present invention can be applied to various electric appliances including electric vacuum cleaners and other household electric appliances.

[0120] Description of Reference Numerals

[0121] 1. Electric fan; 2. Electric motor; 3. Rotating fan; 4. Air guide; 4a. Main body; 4b. Annular part; 4c. Connecting plate; 5. Fan cover; 5a. Cover; 5b. Side wall; 5c. Air inlet; 10. Rotor; 11. Rotor core; 12. Winding coil; 13. Shaft; 13a. First part; 13b. Second part; 14. Commutator; 14a. Commutator segment; 15. First bearing part; 16. Second bearing part; 20. Stator; 21. Magnet; 30. Yoke; 31. Arc part; 32. Straight part; 40. Frame; 40a. Opening; 40b. Exhaust port; 41. Protrusion ; 50, bracket; 50a, inner through hole; 50b, outer through hole; 51, center portion; 52, inner annular portion; 53, outer annular portion; 54, inner bridge portion; 55, outer bridge portion; 60, brush; 61, front end portion; 61a, front end surface (first end); 62, rear end portion; 62a, rear end surface (second end); 70, brush holder; 70a, convex portion; 71, through hole; 72, storage portion; 73, opening portion; 80, constant load spring; 81, spiral portion; 82, outer end portion; 82a, recessed portion; 83, inner end portion; 91, conductive wire; 92, electrode terminal; 100, screw.

Claims

1. An electric motor, wherein: The motor includes: A rotor having a shaft extending along an axial direction and a commutator mounted on the shaft; a brush including, in a radial direction intersecting the axial direction, a first end portion in contact with the commutator and a second end portion located on a side opposite to the first end portion; a brush holder that holds the brush in such a manner that the brush moves along the radial direction; a constant load spring for pressing the brush against the commutator; and electrode terminals that supply power to the brushes, The constant load spring includes a coil portion contacting the second end portion included in the brush and an outer end portion fixed to the brush holder. The electrode terminal is fixed to the brush holder in such a manner that it does not exist on the movement path of the brush moving in the radial direction. The brush holder is provided with a structure for sandwiching the tip of the outer end of the constant load spring. A notch-shaped recess is provided at the outer end portion included in the constant load spring. The brush holder is provided with a convex portion for the concave portion to be engaged. The brush holder is provided with an opening through which the coil portion included in the constant load spring can pass.

2. The electric motor according to claim 1, wherein: The constant load spring is fixed to the brush holder by the outer end portion included in the constant load spring being locked to the brush holder.

3. The electric motor according to claim 1 or 2, wherein: The motor further includes a conductive wire, one end of which is connected to the brush, and the other end of which is connected to an electrode terminal for supplying power to the brush. The length of the conductive wire is set so that the constant load spring applies a pressing force to the brush even when the brush is worn to the maximum extent.

4. The electric motor according to claim 3, wherein: The brush holder has a storage portion for storing the conductive wire. The conductive wire is configured not to exist on a movement path of the brush along the radial direction.

5. The electric motor according to claim 4, wherein: The housing portion has a structure for housing the conductive wire so that the conductive wire does not protrude from the brush holder in a state before the brush is worn.

6. The electric motor according to claim 1 or 2, wherein: The constant load spring is a coil spring having a portion formed by winding a strip-shaped wire as the coil portion.

7. An electric fan, wherein: The electric blower includes: The electric motor according to any one of claims 1 to 6; and A rotary fan is mounted on the shaft provided on the motor.

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