Electric motor

Abstract

The motor includes: a rotor having a rotating shaft extending in an axial direction; a commutator attached to the rotating shaft; a brush having a front end surface in contact with the commutator and a rear end surface located at a position opposite to the front end surface; a constant load spring having a first wrap portion and a second wrap portion, each of which is composed of a strip-shaped wire material wound in a spiral shape, and having a fixed end on the front end surface side; and a pressing member that is in contact with the rear end surface of the brush and presses the brush against the commutator by the load from the constant load spring.

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, 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. Thus, 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, which has a rotating shaft extending along the axial direction; a commutator, which is installed on the rotating shaft; a brush, which 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; a constant load spring, which has a first vortex portion and a second vortex portion respectively composed of a strip-shaped wire wound in a spiral shape, and the constant load spring has a fixed end on the front end face side of the brush; and a pressing member, which contacts the rear end face of the brush and presses the brush against the commutator under the action of the load from the constant load spring.

[0013] Preferably, the pressing member has a first end and a second end which protrude relative to the rear end face of the brush when the brush is observed from the axis in a direction opposite to the direction in which the brush is pressed toward the commutator under the action of the load from the constant load spring, and the load generated by the strip of wire led out from the first spiral portion of the constant load spring during restoration is applied to the first end of the pressing member, and the load generated by the strip of wire led out from the second spiral portion of the constant load spring during restoration is applied to the second end of the pressing member, thereby pressing the brush against the commutator.

[0014] Preferably, the first end of the pressing member contacts an inner surface of the first spiral portion of the constant load spring, and the second end contacts an inner surface of the second spiral portion of the constant load spring.

[0015] Preferably, the first end of the pressing member contacts the outer surface of a portion of the first spiral portion of the constant load spring that is close to the fixed end side of the constant load spring, and the second end contacts the outer surface of a portion of the second spiral portion of the constant load spring that is close to the fixed end side of the constant load spring.

[0016] Preferably, in a cross section cut along a plane passing through the axis of the rotating shaft, the first spiral portion and the second spiral portion of the constant load spring are in contact with the pressing member at one point, respectively.

[0017] The pressing member may have a circular cross-sectional shape at contact portions where the pressing member contacts the first spiral portion and the second spiral portion of the constant load spring.

[0018] Preferably, the rear end surface of the brush is in contact with the pressing member at two points in a cross section taken along a plane passing through the axis of the rotating shaft.

[0019] It is also possible that a recess is formed in the contact portion of the two points of the rear end surface of the brush that contact the pressing member, and in the cross-section when cut by a plane passing through the axis of the rotating shaft, the two points are the contact portions where the pressing member contacts the opening end edge of the recess.

[0020] Preferably, the motor further includes a brush holder having a brush receiving portion for receiving the brush, a first slit extending along the length direction of the brush being formed on one side surface of the brush receiving portion, a second slit extending along the length direction of the brush being formed on the other side surface of the brush receiving portion, the first end portion of the pressing member protruding from the first slit of the brush receiving portion, and the second end portion protruding from the second slit of the brush receiving portion.

[0021] Preferably, the first spiral portion and the second spiral portion of the constant load spring are arranged so as to sandwich the brush housing portion.

[0022] Preferably, the constant load spring includes a connecting portion connecting the belt-shaped wire material constituting the first spiral portion and the belt-shaped wire material constituting the second spiral portion, and the connecting portion is the fixed end of the constant load spring.

[0023] Preferably, the connecting portion of the constant load spring is fixed to the brush holder.

[0024] Alternatively, the pressing member may be a linear and longitudinally elongated rod-shaped member, the first end of the pressing member is one end of the rod-shaped member in the longitudinal direction, and the second end of the pressing member is the other end of the rod-shaped member in the longitudinal direction.

[0025] It may also be that the pressing member comprises: a straight and longitudinally long rod-shaped portion, which contacts the rear end face of the brush and protrudes relative to the rear end face; a first extending portion, which extends from one end of the rod-shaped portion toward the commutator side; and a second extending portion, which extends from the other end of the rod-shaped portion toward the commutator side, the first end of the pressing member is the end of the first extending portion, and the second end of the pressing member is the end of the second extending portion.

[0026] The rear end surface of the brush may be arc-shaped when the brush is viewed from above. The motor of the present disclosure does not need to shorten the brush even when a brush spring having a spiral portion is used, and thus a motor with a long life can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] 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.

[0029] Figure 3 This is an exploded perspective view of the electric blower according to the first embodiment.

[0030] 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.

[0031] Figure 5 This is a perspective view of an assembly in which the brush, the brush holder, the constant load spring, and the pressing member in the motor according to the first embodiment are combined, as seen from an oblique front.

[0032] Figure 6 This is a perspective view of an assembly in which the brush, the brush holder, the constant load spring, and the pressing member in the motor according to the first embodiment are combined, as seen from an oblique rear side.

[0033] Figure 7 This is a diagram showing the structure of an assembly in which a brush, a brush holder, a constant load spring, and a pressing member are combined in the motor according to the first embodiment.

[0034] Figure 8 This is a perspective view showing a state in which the pressing member moves toward the commutator due to wear of the brush in an assembly composed of a brush, a brush holder, a constant load spring, and a pressing member.

[0035] Fig. 9 This is a side view showing a state in which the pressing member moves toward the commutator due to wear of the brush in an assembly composed of a brush, a brush holder, a constant load spring, and a pressing member.

[0036] Fig.10 This is a cross-sectional view showing a brush and a constant load spring provided in a brush holder in a conventional motor.

[0037] Fig.11 This is a diagram showing a brush and a constant load spring in a conventional motor as seen from the back side.

[0038] Fig.12 This is a perspective view showing an assembly in which a brush, a brush holder, a constant load spring, and a pressing member are combined in a motor according to a second embodiment.

[0039] Fig.13 This is a diagram showing the structure of an assembly in which a brush, a brush holder, a constant load spring, and a pressing member are combined in a motor according to a second embodiment.

[0040] Fig.14 This is a perspective view showing an assembly in which a brush, a brush holder, a constant load spring, and a pressing member are combined in a motor according to a third embodiment.

[0041] Fig.15 It is a plan view of an assembly in which a brush, a brush holder, a constant load spring, and a pressing member are combined in a motor according to a third embodiment.

[0042] Fig.16 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 1.

[0043] Fig.17 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 2.

[0044] Fig.18 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 3.

[0045] Fig.19 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 4.

[0046] Fig. 20 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 5.

[0047] Fig.21 It is a diagram showing the structure of a brush, a constant load spring, and a pressing member in a motor according to Modification 6.

[0048] Fig. 22 This is a diagram showing a state in which the pressing member is tilted relative to the brush due to the load difference between the first spiral portion and the second spiral portion of the constant load spring in the electric motor according to the first embodiment.

[0049] Fig.23 This is a diagram showing a state in which the pressing member is tilted relative to the brush due to the load difference between the first spiral portion and the second spiral portion of the constant load spring in the motor of Modification 7. DETAILED DESCRIPTION

[0050] 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.

[0051] 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.

[0052] In addition, 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 substantially 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.

[0053] (Implementation Method 1)

[0054] 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 bold arrows. Figure 3 This is an exploded perspective view of electric blower 1 according to Embodiment 1.

[0055] 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.

[0056] 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.

[0057] 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, a constant load spring 80 as a brush spring, and a pressing member 90. 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.

[0058] The rotary fan 3 draws air into a housing composed of a frame 40 and a fan case 5. As an example, the rotary fan 3 is a centrifugal fan capable of obtaining a 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 case 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, a metal material such as aluminum, etc.

[0059] 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.

[0060] 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. 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In the electric blower 1 configured as described above, when the rotor 10 of the electric motor 2 rotates, the rotary fan 3 rotates, and air is sucked into the fan case 5 from the air inlet 5c of the fan case 5. Thus, air flows into 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, 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 case 5, and reaches the bracket 50 via the ventilation path of the air guide 4.

[0067] Part of the air reaching the bracket 50 flows into the inside of the frame 40 through the bracket 50, and is discharged to the outside from the exhaust port 40b of the frame 40 through the inside 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.

[0068] On the other hand, another part of the air reaching bracket 50 is directly discharged to the outside of electric blower 1 via 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.

[0069] Next, refer to Figure 1 to Figure 3 The detailed structure of each member included in the electric motor 2 will be described.

[0070] like Figure 1 and Figure 2As 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] like Figure 2 As 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.

[0082] 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 .

[0083] like Figure 2As 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.

[0084] 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.

[0085] like 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 .

[0086] 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). In the present embodiment, a plurality of gaps G are formed.

[0087] like Figure 1 to Figure 3 As shown, the frame 40 has a bulging portion 41 that bulges radially outward from 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. For example, the bulging portion 41 can be formed by stamping the side wall of the frame 40.

[0088] like Figure 1 and Figure 2 As 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.

[0089] 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 .

[0090] 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.

[0091] 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 , the constant load spring 80 , and the pressing member 90 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 , the constant load spring 80 , and the pressing member 90 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 , the constant load spring 80 , and the pressing member 90 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, the constant load spring 80, and the pressing member 90 are combined in the motor 2 according to the first embodiment. Figure 7 In the figure, (a) is a top view, (b) is a rear view, (c) is a side view, and (d) is a cross-sectional view taken along the line d-d of (a).

[0092] like Figure 1 , Figure 2 and Figure 4 As shown, the brush 60 is in contact with the commutator 14. Specifically, the brush 60 is in contact with the commutator segment 14a of the commutator 14. The brush 60 is a power supply brush (power-on brush) that supplies power to the winding coil 12 of the rotor 10. For example, a braided wire (not shown) electrically connected to a power supply terminal that receives power from an external power supply is connected to the brush 60. The brush 60 is in contact with the commutator segment 14a, and the current (armature current) supplied to the brush 60 via the braided wire flows to the winding coil 12 of the rotor 10 via the commutator segment 14a.

[0093] 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 metal such as copper and carbon. In the present embodiment, the brush 60 is a carbon brush containing copper. 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.

[0094] like Figure 4 As shown, the brush 60 has a front end surface 61 which is a surface in contact with the commutator 14 , and a rear end surface 62 which is a surface on the opposite side to the front end surface 61 .

[0095] 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.

[0096] The rear end face 62 of the brush 60 is the end face of the rear end portion of the other end in the length direction of the brush 60. The rear end face 62 is the end face of the brush 60 on the side opposite to the rotating shaft 13 side. The rear end face 62 contacts the pressing member 90. Specifically, as Figure 4 As shown, the pressing member 90 contacts the recessed portion 63 formed in the rear end surface 62. That is, the recessed portion 63 is formed in the contact portion of the rear end surface 62 with the pressing member 90.

[0097] like Figure 7 (c) and Figure 7 As shown in (d), the recess 63 is formed in such a way that a part of the rear end surface 62 is recessed toward the front end surface 61. The recess 63 is formed in such a way that the rear end surface 62 is cut out in a rectangular shape in cross-sectional view. Specifically, the shape of the recess 63 in the XZ cross section is rectangular.

[0098] 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.

[0099] The brush 60 is pressed against the commutator 14 by the load generated by the constant load spring 80 via the pressing member 90. Therefore, the brush 60 is directly pressed against the commutator 14 by the pressing member 90. The brush 60 is indirectly pressed against the commutator 14 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 face 61 of the brush 60 is worn due to friction with the commutator 14, and the brush 60 becomes shorter. That is, for the brush 60 pressed toward the commutator 14 by the pressing member 90, as the front end face 61 is worn, the rear end face 62 moves toward the commutator 14.

[0100] 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 the radial direction of the rotating shaft 13). The brush 60 is arranged so that its longitudinal direction is perpendicular to the axis C of the rotating shaft 13 (radial direction).

[0101] 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.

[0102] 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. Therefore, two brush holders 70 are also configured.

[0103] 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 is a substantially square cylindrical shape extending in a longitudinal direction intersecting 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.

[0104] 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.

[0105] 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.

[0106] like Figure 5 to Figure 7As shown in FIG. 1 , 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 recess 73 for fixing the constant load spring 80 is provided in the brush holder 70. The recess 73 is provided at the front end of the brush holder 70. The constant load spring 80 is fixed to the brush holder 70 by inserting a strip-shaped wire material constituting the constant load spring 80 into the recess 73.

[0107] The constant load spring 80 is a brush spring for pressing the brush 60 against the commutator 14 . The constant load spring 80 does not directly apply a load to the brush 60 , but applies a load to a pressing member 90 disposed behind the rear end surface 62 of the brush 60 , thereby pressing the brush 60 against the commutator 14 .

[0108] The constant load spring 80 is a spring for applying a uniform load to the brush 60. The constant load spring 80 applies a uniform load to the brush 60 by applying a uniform load to the pressing member 90. That is, the constant load spring 80 applies a load to the pressing member 90 for causing the pressing member 90 to press the brush 60.

[0109] like 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 having a spiral portion (coil portion) formed by spirally winding the 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.

[0110] The first spiral portion 81 and the second spiral portion 82 are arranged so as to sandwich the brush 60 . The first spiral portion 81 and the second spiral portion 82 are arranged so as to sandwich the brush housing portion 71 of the brush holder 70 .

[0111] The first scroll portion 81 and the second scroll portion 82 are formed in a spiral shape by winding centered on 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 storage portion 71. Therefore, the plate surface of the strip of 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 of 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. In addition, the winding center axis of the first scroll portion 81 and the winding center axis of the second scroll portion 82 are consistent.

[0112] The constant load spring 80 further includes a connecting portion 83 that connects the strip-shaped wire material constituting the first spiral portion 81 and the strip-shaped wire material constituting the second spiral portion 82. The connecting portion 83 of the constant load spring 80 serves as a fixed end of the constant load spring 80. That is, the connecting portion 83 is fixed to a predetermined position. The connecting portion 83 is fixed to the brush holder 70. Specifically, the connecting portion 83 is locked in the recessed portion 73 provided in the brush holder 70.

[0113] The connecting portion 83 is formed of a strip of wire material similar to the first scroll portion 81 and the second scroll portion 82. The wire material constituting the first scroll portion 81, the strip of wire material constituting the second scroll portion 82, and the strip of wire material constituting the connecting portion 83 are integrated. That is, the constant load spring 80 is formed of one wire material. The wire material constituting the first scroll portion 81, the strip of wire material constituting the second scroll portion 82, and the strip of wire material constituting the connecting portion 83 have the same plate width. However, this is not limited to this.

[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 thickness of the metal plate constituting the constant load spring 80 can be wound into a spiral shape, the thickness of the metal plate constituting the constant load spring 80 can also 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 of the brush 60. The strip-shaped wire material constituting the second volute portion 82 is led out along the other side of the brush 60. Specifically, the strip-shaped wire material constituting the first volute portion 81 is led out along one side of the brush housing portion 71 of the brush holder 70 and toward the commutator 14 side. The strip-shaped wire material constituting the second volute portion 82 is led out along the other side of the brush housing portion 71 of the brush holder 70 and toward the commutator 14 side.

[0118] The pressing member 90 presses the brush 60 against the commutator 14 under the load from the constant load spring 80. The pressing member 90 contacts the rear end surface 62 of the brush 60. That is, the pressing member 90 presses the rear end surface 62 of the brush 60 toward the commutator 14 under the load from the constant load spring 80.

[0119] like Figure 7 (a) and Figure 7 As shown in (b), the pressing member 90 has a first end 91 and a second end 92 which protrude respectively relative to the rear end surface 62 of the brush 60. The pressing member 90 is a straight and longitudinal rod-shaped member. Therefore, the first end 91 is one end of the pressing member 90 as a rod-shaped member in the length direction. The second end 92 is the other end of the pressing member 90 as a rod-shaped member in the length direction. As an example, the pressing member 90 is a cylindrical rod-shaped member. However, it is not limited to this. For example, the pressing member 90 may also be a rod-shaped member of a cylindrical shape. As an example, the pressing member 90 is a metal rod made of a metal material. However, it is not limited to this. For example, the pressing member 90 may also be a resin rod made of a resin material.

[0120] The first end 91 and the second end 92 of the pressing member 90 protruding from the rear end surface 62 of the brush 60 are respectively inserted into the first volute 81 and the second volute 82 of the constant load spring 80. Specifically, the first end 91 of the pressing member 90 is inserted into the first volute 81 and contacts the inner surface of the first volute 81. The second end 92 of the pressing member 90 is inserted into the second volute 82 and contacts the inner surface of the second volute 82.

[0121] As described above, the first volute portion 81 and the second volute portion 82 of the constant load spring 80 are arranged so as to sandwich the brush housing portion 71 of the brush holder 70. Therefore, the first end portion 91 and the second end portion 92 of the pressing member 90 protrude from the slits 72 provided on both side surfaces of the brush housing portion 71. Specifically, the first end portion 91 of the pressing member 90 protrudes from the first slit 72a formed in the brush housing portion 71 and is inserted into the first volute portion 81. Similarly, the second end portion 92 of the pressing member 90 protrudes from the second slit 72b formed in the brush housing portion 71 and is inserted into the second volute portion 82.

[0122] The cross-sectional shape of the pressing member 90 is circular at the contact portions where the pressing member 90 contacts the first scroll portion 81 and the second scroll portion 82. Figure 7 As shown in (c) , the first scroll portion 81 and the second scroll portion 82 are in contact with the pressing member 90 at one point, respectively.

[0123] As described above, the pressing member 90 contacts the recess 63 formed on the rear end face 62 of the brush 60. In the XZ section, the cross-sectional shape of the recess 63 is rectangular. The cross-sectional shape of the pressing member 90 is circular. Figure 7 As shown in (d), in the XZ section, the rear end face 62 of the brush 60 contacts the pressing member 90 at two points. Specifically, in the XZ section, the pressing member 90 contacts the rear end face 62 of the brush 60 at two points: the upper opening edge and the lower opening edge of the recess 63.

[0124] The brush 60, brush holder 70, constant load spring 80 and pressing member 90 thus constructed are assembled to the motor 2 as follows. Specifically, the brush 60 is inserted into the brush storage portion 71 of the brush holder 70 toward the commutator 14. The pressing member 90 is arranged behind the rear end face 62 of the brush 60. The first volute portion 81 and the second volute portion 82 of the constant load spring 80 are hooked on the first end portion 91 and the second end portion 92 of the pressing member 90, a strip of wire is led out from the first volute portion 81 and the second volute portion 82 wound in a spiral shape, the connecting portion 83 is inserted into the recess 73, and the connecting portion 83 is fixed to the brush holder 70. In this way, the constant load spring 80 and the pressing member 90 can be provided on the brush holder 70.

[0125] At this time, by leading out the strip-shaped wire from the first scroll portion 81 and the second scroll portion 82, a load is generated in which the strip-shaped wire constituting the first scroll portion 81 and the second scroll portion 82 attempts to restore. Under the action of the load generated by the first scroll portion 81 and the second scroll portion 82, the pressing member 90 presses the brush 60 toward the commutator 14. Specifically, the load generated when the strip-shaped wire led out from the first scroll portion 81 restores is applied to the first end portion 91 of the pressing member 90. The load generated when the strip-shaped wire led out from the second scroll portion 82 restores is applied to the second end portion 92 of the pressing member 90. As a result, the pressing member 90 is pulled toward the commutator 14 side by the first scroll portion 81 and the second scroll portion 82. Therefore, the pressing member 90 in contact with the rear end face 62 of the brush 60 presses the rear end face 62 of the brush 60. Therefore, the brush 60 is pressed against the commutator 14 . In this way, the constant load spring 80 presses the brush 60 against the commutator 14 via the pressing member 90 by the load generated by the first spiral portion 81 and the second spiral portion 82 .

[0126] 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.

[0127] 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 via the pressing member 90, 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 storage portion 71 of the brush holder 70. That is, the rear end face 62 of the brush 60 moves toward the commutator 14.

[0128] At this time, the constant load spring 80 applies a load generated by drawing the strip-shaped wire from the first volute 81 and the second volute 82 to the brush 60 through the pressing member 90. Thus, the pressing member 90 is pressed against the rear end surface 62 of the brush 60 by the load generated by the first volute 81 and the second volute 82.

[0129] Figure 8 This is a perspective view showing a state in which the pressing member 90 moves toward the commutator 14 due to wear of the brush 60 in an assembly composed of the brush 60 , the brush holder 70 , the constant load spring 80 , and the pressing member 90 . Fig. 9 1 is a side view showing a state in which the pressing member 90 moves toward the commutator 14 due to wear of the brush 60 in an assembly composed of the brush 60, the brush holder 70, the constant load spring 80, and the pressing member 90. Figure 8 and Fig. 9 As shown, as the brush 60 wears, the pressing member 90 moves toward the commutator 14, and the first volute 81 and the second volute 82 of the constant load spring 80 try to restore by the spring restoring force. As a result, the strip-shaped wire material constituting the first volute 81 and the second volute 82 are respectively rolled back to the original state. Therefore, as the brush 60 wears, the first volute 81 and the second volute 82 also approach the commutator 14. As a result, the pressing member 90 inserted into the first volute 81 and the second volute 82 moves toward the commutator 14 while pressing the brush 60 toward the commutator 14 as the brush 60 wears.

[0130] Next, the effects of the electric motor 2 of the present embodiment will be described in comparison with a conventional electric motor 2X. Fig.10 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.11 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.

[0131] like Fig.10 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. Therefore, 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. Therefore, the motor 2X is enlarged.

[0132] 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.11 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.

[0133] In contrast, in the motor 2 of the present embodiment, a constant load spring 80 having a first spiral portion 81 and a second spiral portion 82 is used as a brush spring. A pressing member 90 is arranged in contact with the rear end surface 62 of the brush 60. Therefore, by applying a load to the pressing member 90 by the constant load spring 80, the pressing member 90 presses the brush 60 against the commutator 14.

[0134] Specifically, the pressing member 90 has a first end 91 and a second end 92 that protrude respectively from the rear end surface 62 of the brush 60. The load generated when the strip-shaped wire material drawn out from the first volute portion 81 is restored is applied to the first end 91 of the pressing member 90, and the load generated when the strip-shaped wire material drawn out from the second volute portion 82 is restored is applied to the second end 92 of the pressing member 90, thereby pressing the brush 60 against the commutator 14.

[0135] According to this structure, even when 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 when 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 via the pressing member 90. Therefore, even when 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.

[0136] 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.

[0137] In the motor 2 of the present embodiment, the first end 91 of the pressing member 90 is inserted into the first volute 81 of the constant load spring 80 and contacts the inner surface of the first volute 81. The second end 92 of the pressing member 90 is inserted into the second volute 82 of the constant load spring 80 and contacts the inner surface of the second volute 82.

[0138] According to this structure, when the strip-shaped wire material constituting the first scroll portion 81 and the second scroll portion 82 tries to recover due to the wear of the brush 60, the pressing member 90 inserted into the first scroll portion 81 and the second scroll portion 82 is pulled by the first scroll portion 81 and the second scroll portion 82. Thus, the load of the constant load spring 80 can be applied to the brush 60 via the pressing member 90. Therefore, the brush 60 can be pressed against the commutator 14.

[0139] In the present embodiment, the pressing member 90 is a linear and longitudinally long rod-shaped member. The first end 91 is one end of the rod-shaped member in the longitudinal direction. The second end 92 is the other end of the rod-shaped member in the longitudinal direction.

[0140] According to this configuration, the pressing member 90 can be manufactured at low cost. Therefore, when the constant load spring 80 is used to press the brush 60 toward the commutator 14, even when the pressing member 90 is used as a newly added component, a significant increase in the cost of the motor 2 can be suppressed.

[0141] In the motor 2 of the present embodiment, in a cross section (XZ cross section in the present embodiment) when cut by a plane passing through the axis C of the rotating shaft 13, the first scroll portion 81 and the second scroll portion 82 are in contact with the pressing member 90 at one point. Specifically, at the contact portions where the pressing member 90 is in contact with the first scroll portion 81 and the second scroll portion 82, the cross-sectional shape of the pressing member 90 is circular.

[0142] According to this structure, the friction resistance between the first and second volute portions 81, 82 and the pressing member 90 can be reduced. Therefore, the sliding property of the constant load spring 80 can be improved. Thus, the load generated by the first and second volute portions 81, 82 can be stably applied to the pressing member 90.

[0143] In the motor 2 of the present embodiment, in a cross section (XZ cross section in the present embodiment) cut along a plane passing through the axis C of the rotating shaft 13 , the rear end surface 62 of the brush 60 contacts the pressing member 90 at two points.

[0144] According to this structure, when the brush 60 slides, it is possible to suppress the pressing member 90 that is in contact with the rear end surface 62 of the brush 60 from rattling.

[0145] Specifically, a recess 63 is formed in the contact portion of the rear end face 62 of the brush 60 that contacts the pressing member 90. Thus, the pressing member 90 contacts the rear end face 62 of the brush 60 at two points of the opening edge of the recess 63. Specifically, in the XZ cross section, the pressing member 90 contacts the rear end face 62 of the brush 60 at two points of the opening edge on one side and the opening edge on the other side of the recess 63 in the Z-axis direction. Thus, it is possible to suppress the pressing member 90 from shaking in the Z-axis direction.

[0146] In the motor 2 of the present embodiment, a first slit 72a and a second slit 72b extending along the length direction of the brush 60 are formed on one side and the other side of the brush storage portion 71 of the brush holder 70, respectively. The first end 91 of the pressing member 90 protrudes from the first slit 72a. The second end 92 of the pressing member 90 protrudes from the second slit 72b.

[0147] According to this structure, when the brush 60 is worn and the strip-shaped wire material constituting the first scroll portion 81 and the second scroll portion 82 is wound back to the original state, the pressing member 90 can be slid along the first slit 72a and the second slit 72b toward the commutator 14. That is, the pressing member 90 can be moved toward the commutator 14 while being held on the brush holder 70. In this way, the first slit 72a and the second slit 72b function as a guide portion when the pressing member 90 moves toward the commutator 14 side.

[0148] In the motor 2 of the present embodiment, the first volute 81 and the second volute 82 of the constant load spring 80 are arranged to sandwich the brush housing 71 housing the brush 60 .

[0149] According to this configuration, even when the constant load spring 80 having the first spiral portion 81 and the second spiral portion 82 is used, it is possible to suppress the height of the motor 2 from increasing. Therefore, a compact motor 2 can be realized.

[0150] In the motor 2 of this embodiment, the constant load spring 80 has a connecting portion 83 connecting the strip-shaped wire material constituting the first spiral portion 81 and the strip-shaped wire material constituting the second spiral portion 82. The connecting portion 83 is a fixed end of the constant load spring 80.

[0151] According to this structure, the direction of the load generated by the strip-shaped wire material drawn out from the first scroll portion 81 and the second scroll portion 82 when restoring is not the direction in which the connecting portion 83 moves toward the first scroll portion 81 and the second scroll portion 82, but the direction in which the first scroll portion 81 and the second scroll portion 82 move toward the connecting portion 83. Therefore, when the brush 60 is worn, the connecting portion 83 does not move toward the first scroll portion 81 and the second scroll portion 82, but the first scroll portion 81 and the second scroll portion 82 move toward the connecting portion 83. By generating a load in the direction in which the first scroll portion 81 and the second scroll portion 82 move toward the connecting portion 83, the pressing member 90 can be pressed against the rear end surface 62 of the brush 60 by the load of the first scroll portion 81 and the second scroll portion 82. As a result, the brush 60 is pressed toward the commutator 14 by the pressing member 90.

[0152] In this case, the connection part 83 of the constant load spring 80 is fixed to the brush holder 70. Specifically, the connection part 83 is fixed to the recessed part 73 of the brush holder 70.

[0153] According to this structure, the constant load spring 80 can be easily fixed to the brush holder 70 using the connecting portion 83 as a fixed end.

[0154] As described above, the motor 2 of the present embodiment includes: a rotor 10 having a rotating shaft 13 extending in an axial direction; a commutator 14 mounted on the rotating shaft 13; a brush 60 having a front end face 61 in contact with the commutator 14 and a rear end face 62 located on the opposite side of the front end face 61; a constant load spring 80 having a first volute portion 81 and a second volute portion 82 each consisting of a strip-shaped wire material wound in a spiral shape, and the constant load spring 80 having a fixed end on the front end face 61 side of the brush 60; and a pressing member 90 in contact with the rear end face 62 of the brush 60, pressing the brush 60 against the commutator 14 under the action of the load from the constant load spring 80.

[0155] This makes it possible to realize a motor with a long life.

[0156] (Implementation Method 2)

[0157] Next, use Fig.12 and Fig.13 Implementation method 2 will be described. Fig.12 1 is a perspective view showing an assembly in which the brush 60 , the brush holder 70 , the constant load spring 80 , and the pressing member 90A are combined in the electric motor 2A according to the second embodiment. Fig.13 1 is a diagram showing the structure of an assembly in which the brush 60, the brush holder 70, the constant load spring 80, and the pressing member 90A are combined in the motor 2A of the second embodiment. Fig.13In the figure, (a) is a top view, (b) is a rear view, (c) is a side view, and (d) is a cross-sectional view taken along the line d-d of (a).

[0158] The motor 2A of this embodiment is different from the motor 2 of the first embodiment in the structure of the pressing member 90A. Specifically, the pressing member 90A of this embodiment is configured to further include a first retaining portion 91a and a second retaining portion 92a in addition to the pressing member 90 of the first embodiment.

[0159] The first anti-slip portion 91a has a function of preventing the pressing member 90A inserted into the first volute portion 81 of the constant load spring 80 from falling off from the first volute portion 81. The first anti-slip portion 91a is provided at the first end portion 91 of the pressing member 90A. The first anti-slip portion 91a is a large-diameter portion having a larger diameter than the cylindrical rod-shaped portion of the pressing member 90A. As an example, the first anti-slip portion 91a is in the shape of a disk.

[0160] The second anti-slip portion 92a has a function of preventing the pressing member 90A inserted into the second volute portion 82 of the constant load spring 80 from falling off from the second volute portion 82. The second anti-slip portion 92a is provided at the second end portion 92 of the pressing member 90A. The second anti-slip portion 92a is a large-diameter portion having a larger diameter than the cylindrical rod-shaped portion of the pressing member 90A. As an example, the second anti-slip portion 92a is in the shape of a disk.

[0161] The shapes of the first anti-slip portion 91a and the second anti-slip portion 92a are not limited to the disc shape. The shapes of the first anti-slip portion 91a and the second anti-slip portion 92a can be any shape as long as the pressing member 90A does not fall off from the first scroll portion 81 or the second scroll portion 82. For example, the shapes of the first anti-slip portion 91a and the second anti-slip portion 92a can be any shape as long as the pressing member 90A is caught on the first scroll portion 81 or the second scroll portion 82 when the pressing member 90A moves in the direction of falling off from the first scroll portion 81 or the second scroll portion 82.

[0162] The motor 2A of the present embodiment has the same structure as the motor 2 of the above-described first embodiment except that the pressing member 90A includes the first retaining portion 91 a and the second retaining portion 92 a .

[0163] Therefore, the motor 2A of this embodiment has the same effect as the motor 2 of the above-mentioned embodiment 1. For example, in the motor 2A of this embodiment, as in the above-mentioned embodiment 1, the constant load spring 80 having the first spiral portion 81 and the second spiral portion 82 applies a load to the pressing member 90A, so that the pressing member 90A presses the brush 60 against the commutator 14.

[0164] According to this structure, even when the constant load spring 80 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.

[0165] In the electric motor 2A, the pressing member 90A includes a first retaining portion 91 a and a second retaining portion 92 a .

[0166] According to this structure, the constant load spring 80 applies a load in the direction of the commutator 14 to the pressing member 90A. Fig.13 As shown in (c), when viewed from the side, the first anti-slip portion 91a and the second anti-slip portion 92a of the pressing member 90A overlap with parts of the first volute portion 81 and the second volute portion 82. Thus, when the pressing member 90A moves along the Y-axis direction, the first anti-slip portion 91a is hooked on the first volute portion 81, or the second anti-slip portion 92a is hooked on the second volute portion 82. Therefore, it is possible to prevent the pressing member 90A from falling off from the first volute portion 81 or the second volute portion 82 when the brush 60 slides and the pressing member 90A moves toward the commutator 14.

[0167] (Implementation method 3)

[0168] Next, use Fig.14 and Fig.15 Describe implementation mode 3. Fig.14 1 is a perspective view showing an assembly in which the brush 60 , the brush holder 70 , the constant load spring 80 , and the pressing member 90B are combined in the motor 2B according to the third embodiment. Fig.15 1 is a plan view of an assembly in which the brush 60 , the brush holder 70 , the constant load spring 80 , and the pressing member 90B are combined in the motor 2B according to the third embodiment.

[0169] The motor 2B of the present embodiment is different from the motor 2 of the above-mentioned embodiment 1 in the structure of the pressing member 90B. Specifically, in the motor 2 of the above-mentioned embodiment 1, the pressing member 90 is composed of only a straight and longitudinally long rod-shaped member. However, in the motor 2B of the present embodiment, the pressing member 90B has a straight and longitudinally long rod-shaped portion 93, a first extension portion 94, and a second extension portion 95. The first extension portion 94 extends from one end of the rod-shaped portion 93 toward the commutator 14 side. The second extension portion 95 extends from the other end of the rod-shaped portion 93 toward the commutator 14 side.

[0170] The rod-shaped portion 93 is in contact with the rear end surface 62 of the brush 60. The rod-shaped portion 93 protrudes relative to the rear end surface 62 of the brush 60. The rod-shaped portion 93 is, for example, cylindrical.

[0171] The first extension portion 94 extends along one side surface of the brush 60 . The end of the first extension portion 94 is a first end portion 91B of the pressing member 90B. The first end portion 91B is formed to protrude from the end of the first extension portion 94 to the side opposite to the brush 60 side.

[0172] The first end portion 91B, which is the end portion of the first extension portion 94, contacts the first volute portion 81 of the constant load spring 80. The first end portion 91B contacts the outer surface of the portion of the first volute portion 81 on the fixed end side of the constant load spring 80. That is, the first end portion 91B contacts the outer surface of the portion on the connecting portion 83 side of the first volute portion 81 and the outer surface of the portion on the side opposite to the connecting portion 83 side, the outer surface of the portion on the connecting portion 83 side. The first end portion 91B has a cylindrical surface that contacts the outer surface of the first volute portion 81.

[0173] The second extension portion 95 extends along the other side surface of the brush 60. The end of the second extension portion 95 is a second end portion 92B of the pressing member 90B. The second end portion 92B is formed to protrude from the end of the second extension portion 95 to the side opposite to the brush 60 side.

[0174] The second end portion 92B, which is the end portion of the second extension portion 95, contacts the second volute portion 82 of the constant load spring 80. The second end portion 92B contacts the outer surface of the portion of the second volute portion 82 on the fixed end side of the constant load spring 80. That is, the second end portion 92B contacts the outer surface of the portion on the connecting portion 83 side of the second volute portion 82 and the outer surface of the portion on the side opposite to the connecting portion 83 side, the outer surface of the portion on the connecting portion 83 side. The second end portion 92B has a cylindrical surface that contacts the outer surface of the second volute portion 82.

[0175] The motor 2B having such a configuration is different from the motor 2 of the first embodiment described above in the manner in which the constant load spring 80 applies the load to the pressing member 90B.

[0176] Specifically, in the first embodiment, the first end 91 of the pressing member 90 is inserted into the first volute 81 of the constant load spring 80 and contacts the inner surface of the first volute 81, and the second end 92 of the pressing member 90 is inserted into the second volute 82 of the constant load spring 80 and contacts the inner surface of the second volute 82. Thus, the first volute 81 and the second volute 82 pull the first end 91 and the second end 92 of the pressing member 90 toward the commutator 14, respectively, and apply a load to the pressing member 90.

[0177] In contrast, in the present embodiment, the first end 91B of the pressing member 90B contacts the outer surface of the portion of the first volute 81 that is close to the commutator 14 side (fixed end side) of the constant load spring 80, and the second end 92B of the pressing member 90B contacts the outer surface of the portion of the second volute 82 that is close to the commutator 14 side (fixed end side) of the constant load spring 80. According to this structure, the first volute 81 and the second volute 82 apply a load to the first end 91B and the second end 92B of the pressing member 90B, respectively, by pressing toward the commutator 14 side.

[0178] The motor 2B of the present embodiment has the same structure as the motor 2 of the above-described first embodiment except for the pressing member 90B.

[0179] Therefore, the motor 2B of this embodiment has the same effect as the motor 2 of the above embodiment. For example, in the motor 2B of this embodiment, as in the above embodiment 1, the constant load spring 80 having the first volute portion 81 and the second volute portion 82 applies a load to the pressing member 90B, so that the pressing member 90B presses the brush 60 against the commutator 14.

[0180] According to this structure, even when the constant load spring 80 is used as the brush spring, there is no need to shorten the length of the brush 60. Therefore, a motor 2B 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 2B can be easily realized.

[0181] (Variation Example)

[0182] As mentioned above, the technology of this disclosure has been described based on Embodiments 1 to 3. However, the technology of this disclosure is not limited to Embodiments 1 to 3 described above.

[0183] For example, in the above-described first to third embodiments, the recessed portion 63 is formed on the rear end surface 62 of the brush 60. However, the present invention is not limited thereto. Fig.16 1 is a diagram showing the structure of the brush 60C, the constant load spring 80 and the pressing member 90 in the motor of the modification example 1. Specifically, Fig.16 As shown, a brush 60C may be used in which the recessed portion 63 is not formed on the rear end surface 62. In this case, the pressing member 90 having a circular cross-sectional shape contacts the rear end surface 62 of the brush 60C at one point instead of two points.

[0184] In the first to third embodiments described above, the cross-sectional shape of the pressing member 90 at the contact portion with the rear end surface 62 of the brush 60 is circular, but the present invention is not limited thereto. Fig.17 1 is a diagram showing the structure of the brush 60, the constant load spring 80 and the pressing member 90D in the motor of the modification example 2. Fig.17 As shown, the cross-sectional shape of the pressing member 90D at the contact portion with the rear end face 62 of the brush 60 is rectangular. In this case, the pressing member 90 is in surface contact with the rear end face 62 of the brush 60C rather than in point contact. The cross-sectional shape of the pressing member 90D is, for example, a rectangle. However, the cross-sectional shape of the pressing member 90D may also be a rhombus or the like.

[0185] exist Fig.17 In the embodiment, the pressing member 90D and the first scroll portion 81 are not in contact at one point, but at two points. Therefore, in this modification, compared with the above-mentioned embodiments 1 to 3, the friction resistance between the pressing member 90D and the first scroll portion 81 becomes larger, and the sliding property of the constant load spring 80 may be slightly worse.

[0186] Fig.18 1 is a diagram showing the structure of the brush 60, the constant load spring 80 and the pressing member 90D in the motor of the modification example 3. In the case of using the pressing member 90D having a rectangular cross-sectional shape, as shown in FIG. Fig.18 As shown in FIG. 1 , it is better to make the pressing member 90D contact the recess 63 of the brush 60 in such a way that only one corner of the pressing member 90D contacts the first volute 81. Thus, the pressing member 90D contacts the first volute 81 at one point, so that the friction resistance between the pressing member 90D and the first volute 81 can be reduced. Therefore, the sliding property of the constant load spring 80 can be improved. Moreover, in Fig.18 In the embodiment, the pressing member 90D is in contact with the rear end surface 62 of the brush 60 at two points. This can also suppress the pressing member 90D from rattling when the brush 60 slides.

[0187] Fig.19 1 is a diagram showing the structure of the brush 60E, the constant load spring 80 and the pressing member 90D in the motor of the modification example 4. When the pressing member 90D having a rectangular cross-sectional shape is used, it may be as follows Fig.19 As shown in FIG. 1 , the shape of the recess 63E formed on the rear end surface 62 of the brush 60E is not a rectangle but a triangle. Thus, the pressing member 90D can be fitted into the recess 63E. Therefore, the pressing member 90D can be further suppressed from rattling when the brush 60E slides.

[0188] Fig. 20 1 is a diagram showing the structure of the brush 60F, the constant load spring 80 and the pressing member 90F in the motor of the modification example 5. Fig. 20 As shown, a pressing member 90F having a triangular cross-sectional shape is used. In this case, the recessed portion 63F formed in the rear end surface 62 of the brush 60F may be formed so as to contact one side surface of the pressing member 90F. Fig.216 is a diagram showing the structure of the brush 60F, the constant load spring 80 and the pressing member 90G in the motor of the modification example 6. Fig.21 As shown in FIG. 1 , a pressing member 90G having an arc-shaped cross section is used.

[0189] In the constant load spring 80 of the first embodiment, the load applied to the brush 60 by the first scroll portion 81 via the pressing member 90 and the load applied to the brush 60 by the second scroll portion 82 via the pressing member 90 are substantially the same. However, due to manufacturing errors, etc., there may be a deviation between the load generated by the first scroll portion 81 and the load generated by the second scroll portion 82. In this case, due to the load difference between the first scroll portion 81 and the second scroll portion 82, the pressing member 90 may tilt as the brush 60 slides. Fig. 22 1 is a diagram showing a situation in which the pressing member 90 is tilted relative to the brush due to the load difference between the first spiral portion 81 and the second spiral portion 82 of the constant load spring 80 in the motor of the first embodiment. Fig. 22 As shown, when the load of the second volute 82 is greater than the load of the first volute 81, when the state changes from the initial state (a) before the brush 60 is worn to the state (b) after the brush 60 is worn, the pressing member 90 tilts toward the second volute 82 side with a larger load. In this case, the load generated by the constant load spring 80 through the pressing member 90 is concentrated on the corner of the end edge of the rear end surface 62 of the brush 60. As a result, there is a concern that the brush 60 pressed by the pressing member 90 tilts and the sliding property of the brush 60 is reduced.

[0190] Fig.23 FIG. 1 is a diagram showing a state in which the pressing member 90 is tilted relative to the brush 60H due to the load difference between the first spiral portion 81 and the second spiral portion 82 of the constant load spring in the motor of the modification 7. Fig.23 As shown in FIG. 1 , it is better to use a brush 60H whose rear end surface 62 is in an arc shape when viewed from above. Thus, even if the pressing member 90 tilts as the brush 60H slides due to the load difference between the first volute 81 and the second volute 82, the brush 60H can be prevented from tilting. Specifically, Fig.23 As shown, when the load of the second volute 82 is greater than the load of the first volute 81, when the state changes from the initial state (a) before the brush 60H is worn to the state (b) after the brush 60H is worn, the pressing member 90 tilts toward the second volute 82 with a larger load. However, the load generated by the constant load spring 80 via the pressing member 90 is not concentrated on the edge of the rear end face 62 of the brush 60H, but is concentrated on a portion closer to the center than the edge of the rear end face 62. As a result, the brush 60H pressed by the pressing member 90 can be suppressed from tilting. Therefore, the reduction in the sliding property of the brush 60H can be suppressed.

[0191] In the above-mentioned embodiments 1 to 3, the constant load spring 80 is arranged in a posture (horizontally arranged posture) in which the arrangement direction of the first scroll portion 81 and the second scroll portion 82 is parallel to the XY plane. However, it is not limited to this. Specifically, the constant load spring 80 may also be arranged in a posture (vertically arranged posture) in which the arrangement direction of the first scroll portion 81 and the second scroll portion 82 is parallel to the Z-axis direction.

[0192] 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.

[0193] 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.

[0194] In the above embodiment, the 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, but may be used in industrial equipment.

[0195] 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.

[0196] Industrial Applicability

[0197] 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.

[0198] Description of Reference Numerals

[0199] 1. Electric fan; 2. 2A, 2B, 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. Protruding portion; 50. Bracket; 51, first through hole; 52, second through hole Hole; 60, 60C, 60E, 60F, 60H, brush; 61, front end face; 62, rear end face; 63, 63E, 63F, recess; 70, brush holder; 71, brush storage portion; 72, slit; 72a, first slit; 72b, second slit; 73, recess; 80, constant load spring; 81, first scroll portion; 82, second scroll portion; 83, connecting portion; 90, 90A, 90B, 90D, 90F, 90G, pressing member; 91, 91B, first end portion; 91a, first anti-detachment portion; 92, 92B, second end portion; 92a, second anti-detachment portion; 93, rod-shaped portion; 94, first extension portion; 95, second extension portion.

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 having a front end surface in contact with the commutator and a rear end surface located on a side opposite to the front end surface; a constant load spring having a first spiral portion and a second spiral portion each consisting of a belt-shaped wire material wound in a spiral shape, and having a fixed end on the front end surface side of the brush; and A pressing member contacts the rear end surface of the brush and presses the brush against the commutator under the load from the constant load spring.

2. The electric motor according to claim 1, wherein: The pressing member has a first end and a second end which protrude relative to the rear end surface of the brush when the brush is viewed from the axis in a direction opposite to a direction in which the brush is pressed toward the commutator under the load from the constant load spring. The load generated by the strip-shaped wire led out from the first spiral portion of the constant load spring during restoration is applied to the first end portion of the pressing member, and the load generated by the strip-shaped wire led out from the second spiral portion of the constant load spring during restoration is applied to the second end portion of the pressing member, thereby pressing the brush against the commutator.

3. The electric motor according to claim 2, wherein: The first end portion of the pressing member contacts an inner surface of the first spiral portion of the constant load spring, and the second end portion contacts an inner surface of the second spiral portion of the constant load spring.

4. The electric motor according to claim 2, wherein: The first end of the pressing member contacts the outer surface of the first spiral portion of the constant load spring that is close to the fixed end side of the constant load spring, and the second end contacts the outer surface of the second spiral portion of the constant load spring that is close to the fixed end side of the constant load spring.

5. The electric motor according to any one of claims 1 to 4, wherein: The first spiral portion and the second spiral portion of the constant load spring are in contact with the pressing member at one point, respectively, in a cross section cut along a plane passing through the axis of the rotating shaft.

6. The electric motor according to claim 5, wherein: The pressing member has a circular cross-sectional shape at contact portions where the pressing member contacts the first spiral portion and the second spiral portion of the constant load spring, respectively.

7. The electric motor according to any one of claims 1 to 4, wherein: The rear end surface of the brush is in contact with the pressing member at two points in a cross section taken along a plane passing through the axis of the rotating shaft.

8. The electric motor according to claim 7, wherein: A recess is formed in a contact portion of the rear end surface of the brush with the pressing member. The two points are contact portions where the pressing member contacts the opening end edge of the recessed portion in a cross section taken along a plane passing through the axis of the rotating shaft.

9. The electric motor according to any one of claims 2 to 4, wherein: The motor further includes a brush holder having a brush receiving portion for receiving the brush. A first slit extending along the length direction of the brush is formed on one side surface of the brush housing portion. A second slit extending along the length direction of the brush is formed on the other side surface of the brush housing portion. The first end portion of the pressing member protrudes from the first slit of the brush housing portion, and the second end portion protrudes from the second slit of the brush housing portion.

10. The electric motor according to claim 9, wherein The first spiral portion and the second spiral portion of the constant load spring are arranged so as to sandwich the brush housing portion.

11. The electric motor according to claim 9, wherein: The constant load spring includes a connecting portion connecting the strip-shaped wire material constituting the first spiral portion and the strip-shaped wire material constituting the second spiral portion. The connecting portion is the fixed end of the constant load spring.

12. The electric motor according to claim 11, wherein The connecting portion of the constant load spring is fixed to the brush holder.

13. The electric motor according to any one of claims 2 to 4, wherein: The pressing member is a straight and longitudinally elongated rod-shaped member. The first end portion of the pressing member is an end portion of the rod-shaped member in the longitudinal direction. The second end portion of the pressing member is the other end portion in the longitudinal direction of the rod-shaped member.

14. The electric motor according to any one of claims 2 to 4, wherein: The pressing member comprises: a straight and longitudinally long rod-shaped portion which contacts the rear end surface of the brush and protrudes relative to the rear end surface; and a first extending portion which extends from one end of the rod-shaped portion toward the commutator side. and a second extending portion extending from the other end of the rod-shaped portion toward the commutator side, The first end portion of the pressing member is an end portion of the first extending portion, The second end portion of the pressing member is an end portion of the second extending portion.

15. The electric motor according to any one of claims 1 to 4, wherein: When the brush is viewed from above, the rear end surface of the brush is arc-shaped.

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