Electric motors and electric blowers

Abstract

Provided is an electric motor capable of reducing influence of magnetic flux, which is generated by an armature winding, on a constant force spring. A magnetic motor (1) comprises: a rotor (20) having a rotation shaft (21), and a commutator (30) attached to the rotation shaft (21); a brush (40) adjacent to the commutator (30); a plurality of armature windings (22) connected to the commutator (30); a constant force spring (110); and a soft magnetic member (second bracket (102)) which is disposed between the plurality of armature windings (22) and the constant force spring (110), and shields magnetic flux generated by the plurality of armature windings (22). The constant force spring (110) is formed by a band-like plate material, and presses the brush (40) against the commutator (30).

Description

Technical Field

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

Background Art

[0002] Electric motors are widely used in the electrical equipment field mounted on vehicles such as automobiles. For example, in two-wheeled or four-wheeled vehicles, an electric motor is used to drive a cooling fan that cools a radiator and a battery.

[0003] As electric motors, a brushed electric motor using brushes and a brushless electric motor not using brushes are known. Among these, a brushed electric motor includes a stator, a rotor that rotates by the magnetic force of the stator, a commutator attached to the rotation axis of the rotor, a brush that slidably contacts the commutator, and a spring for pressing the brush against the commutator (see, for example, Patent Document 1). In such an electric motor, the brush wears and its length decreases according to the operating time. In the electric motor described in Patent Document 1, by using a constant load spring as the spring for pressing the brush against the commutator, it is attempted to suppress the variation in the force with which the constant load spring presses the brush against the commutator as the length of the brush decreases.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The constant-load spring described in Patent Document 1 consists of a strip-shaped wire. This strip-shaped wire is made of a non-magnetic material so as not to be affected by the magnetic flux generated by the armature winding. However, even if the constant-load spring is made of austenitic stainless steel, which is a non-magnetic material, it will become magnetized due to the processing stress when winding the strip-shaped wire. In particular, because the constant-load spring has a strip shape, its surface area is large. Therefore, if the constant-load spring becomes magnetized, the force it receives from the magnetic flux cannot be ignored. As a result, the magnetic flux generated by the armature winding pulls the constant-load spring towards the armature winding. This can cause the direction in which the constant-load spring pushes the brush to fluctuate, or the load to fluctuate.

[0006] This disclosure is made to solve such problems and aims to provide an electric motor and an electric blower equipped with the same that can suppress the influence of the magnetic flux generated by the armature winding on a constant load spring.

[0007] To achieve the above objective, one embodiment of the electric motor according to the present disclosure comprises a rotor having a rotating shaft, a commutator attached to the rotor, brushes in contact with the commutator, a plurality of armature windings connected to the commutator, a constant-load spring made of a strip-shaped wire that presses the brushes against the commutator, and a soft magnetic member disposed between the plurality of armature windings and the constant-load spring that shields the magnetic flux generated by the plurality of armature windings.

[0008] To achieve the above objective, one embodiment of the electric blower according to this disclosure comprises the electric motor and a fan attached to the rotating shaft.

[0009] According to this disclosure, it is possible to realize an electric motor and an electric blower equipped therewith that can suppress the effect of the magnetic flux generated by the armature winding on a constant load spring. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view of the electric motor according to the embodiment, as seen from below. [Figure 2] Figure 2 is a perspective view of the electric motor according to the embodiment, as seen from above. [Figure 3] Figure 3 is a cross-sectional view of an electric motor according to an embodiment. [Figure 4] Figure 4 is a perspective view showing the internal structure of the brush holder in an electric motor according to an embodiment. [Figure 5] Figure 5 is a perspective view showing the configuration of a constant-load spring according to an embodiment. [Figure 6] Figure 6 is an enlarged cross-sectional view of a part of the electric motor according to the embodiment. [Figure 7] Figure 7 is a plan view showing a modified arrangement of the constant-load spring 110 and the brush 40. [Figure 8] Figure 8 is a perspective view showing a fan attached to an electric motor according to an embodiment. [Figure 9] Figure 9 is a schematic diagram of an electric blower, including a fan attached to an electric motor. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit this disclosure. Accordingly, any components in the following embodiments that are not described in the independent claims representing the highest-level concepts of this disclosure will be described as optional components.

[0012] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. In addition, the same reference numerals are used for substantially identical components in each figure, and redundant explanations are omitted or simplified. Moreover, in this specification, the terms "up" and "down" do not necessarily refer to the upward direction (vertically upward) and the downward direction (vertically downward) in absolute spatial perception.

[0013] (Embodiment) [1. Overall Structure] First, the overall configuration of the electric motor 1 according to this embodiment will be explained using Figures 1 to 4. Figure 1 is an external perspective view of the electric motor 1 according to this embodiment, viewed from below. Figure 2 is an external perspective view of the same electric motor 1, viewed from above. Figure 3 is a cross-sectional view of the same electric motor 1. Specifically, Figure 3 is a cross-sectional view taken along line III-III, where the electric motor 1 shown in Figure 2 is cut by a plane passing through the center of the rotation axis 21 and passing through line segment III-III and parallel to the rotation axis 21. Figure 4 is a perspective view showing the internal structure of the brush holder 50 in the electric motor 1. Note that in Figure 3, only the parts that appear in the cross-section of the electric motor 1 are shown. Figure 4 also shows a perspective view of the brush holder 50 with the cover plate 131 removed, viewed from below.

[0014] As shown in Figure 3, the electric motor 1 comprises a stator 10 and a rotor 20 that rotates due to the magnetic force of the stator 10. The electric motor 1 according to this embodiment is a brushed electric motor, and further, as shown in Figure 3, it is equipped with a commutator 30 attached to a rotating shaft 21 provided on the rotor 20, and also with two brushes 40 that are in contact with the commutator 30.

[0015] As shown in Figures 3 and 4, the electric motor 1 further includes a brush holder 50 for holding the brushes 40 and a constant-load spring 110 for pressing the brushes 40 against the commutator 30. The electric motor 1 also includes a bearing 91, a first bracket 101, and a second bracket 102.

[0016] The electric motor 1 according to this embodiment is a type of direct current motor (DC motor) driven by direct current. A magnet 11 is used as the stator 10, and an armature having an armature winding 22 is used as the rotor 20. Also, in this embodiment, the electric motor 1 is a flat brushless coreless motor (flat motor) mounted on a vehicle such as a two-wheeled or four-wheeled vehicle. Therefore, the stator 10 and the rotor 20 do not have a core (iron core), and the electric motor 1 has a configuration that is thin and light as a whole. In this embodiment, the thickness of the electric motor 1 (that is, the dimension in the direction of the axis C of the rotation shaft 21) is smaller than the outer diameter (the dimension in the direction perpendicular to the direction of the axis C). Specifically, the electric motor 1 according to this embodiment is a small motor used for the cooling fan of the radiator in a vehicle, and the outer diameter (diameter) of the electric motor 1 is 120 mm or less. As an example, the outer diameter of the electric motor 1 is 62 mm. Note that the electric motor 1 is driven by an input voltage of DC 12V.

[0017] Hereinafter, each component of the electric motor 1 will be described in detail.

[0018] As shown in FIG. 3, the stator 10 is arranged with a minute air gap 12 between it and the rotor 20. The stator 10 generates a magnetic force acting on the rotor 20. The stator 10 is configured to generate magnetic flux on the air gap surface 12a with the rotor 20, and constitutes a magnetic circuit together with the rotor 20 which is an armature. Specifically, the stator 10 is substantially donut-shaped as a whole, and is configured such that N poles and S poles alternately and evenly exist on the air gap surface 12a with the rotor 20 along the circumferential direction of the rotation shaft 21. The stator 10 is a field magnet that creates magnetic flux for generating torque, and in this embodiment, it is composed of a plurality of magnets 11 (magnets). The magnet 11 is, for example, a permanent magnet having S and N poles.

[0019] The plurality of magnets 11 that constitute the stator 10 are arranged such that N poles and S poles alternately and evenly exist over the circumferential direction. In the present embodiment, the direction of the main magnetic flux generated by the stator 10 (magnet 11) is a direction along the direction in which the rotation axis 21 extends. The direction of the main magnetic flux is generated in a direction corresponding to the magnetic poles of the magnet 11. The stator 10 is fixed to the first bracket 101.

[0020] As shown in FIG. 3, the rotor 20 has a rotation axis 21 and rotates about the axis center C of the rotation axis 21. The rotor 20 generates a magnetic force acting on the stator 10. In the present embodiment, the direction of the main magnetic flux generated by the rotor 20 is a direction along the direction in which the rotation axis 21 extends. The direction of the main magnetic flux is generated in a direction corresponding to the direction of the current flowing through the armature winding 22.

[0021] The rotor 20 is arranged to face the stator 10. In the present embodiment, the rotor 20 faces the stator 10 in the direction of the axis center C of the rotation axis 21.

[0022] [[ID=eleven]] The rotation axis 21 is a shaft having an axis center C and is a long bar-shaped member such as a metal bar. The axis center C of the rotation axis 21 is the center when the rotor 20 rotates. The longitudinal direction of the rotation axis 21, that is, the direction in which the rotation axis 21 extends (extension direction) is also referred to as the direction of the axis center C (axis center direction).

[0023] The rotation axis 21 is supported by a bearing 91. As an example, the bearing 91 is a bearing such as a ball bearing.

[0024] In the present embodiment, the first end portion 21a of the rotation axis 21 is an end portion on the output side (output shaft) and protrudes from the first bracket 101 and the bearing 91. A load such as a fan is attached to the first end portion 21a. Note that the second end portion 21b of the rotation axis 21 is an end portion on the anti-output side (anti-output shaft) and protrudes from the second bracket 102.

[0025] The bearing 91 is held by the first bracket 101. Specifically, the bearing 91 is fixed to a recess provided in the first bracket 101.

[0026] The first bracket 101, together with the second bracket 102, is a component that constitutes the housing. The stator 10 and rotor 20 are arranged inside the housing formed by the first bracket 101 and the second bracket 102. In this embodiment, the first bracket 101 is an outer component of the electric motor 1 and is formed in a closed-bottom cylindrical shape having a bottom and cylindrical side walls. The magnets 11 that constitute the stator 10 are fixed to the bottom of the first bracket 101. The armature windings 22 of the rotor 20 are surrounded by the side walls of the first bracket 101. The first bracket 101 is made of, for example, a metal material. For example, the first bracket 101 is made of an iron-based material such as cold-rolled steel sheet (SPC material) or a metal such as aluminum. The material of the first bracket 101 is not limited to a metal material and may be a resin material, but from the viewpoint of suppressing noise generated from the electric motor 1, it is preferable that the first bracket 101 be made of a metal material.

[0027] The second bracket 102 is a component that, together with the first bracket 101, constitutes the housing. The second bracket 102 is made of a plate-shaped soft magnetic material. The second bracket 102 is an example of a soft magnetic member that is positioned between the multiple armature windings 22 and the constant-load spring 110 and shields the magnetic flux generated by the multiple armature windings 22. In this embodiment, the second bracket 102 is made of an iron plate. However, the soft magnetic material that constitutes the second bracket 102 is not limited to iron. For example, permalloy, silicon iron, etc., can be used as the soft magnetic material.

[0028] As shown in Figure 3, the rotor 20 includes a rotating shaft 21, a plurality of armature windings 22, and a molded resin 23 that covers the plurality of armature windings 22.

[0029] Each of the multiple armature windings 22 is made of electric wire and is wound in such a way that it generates a magnetic force that acts on the stator 10 when current flows through it. In this embodiment, the direction of the main magnetic flux generated by each armature winding 22 is in the direction of the axis C of the rotation shaft 21. In other words, the magnets 11 of the stator 10 and the armature windings 22 of the rotor 20 are aligned in the direction of the axis C of the rotation shaft 21.

[0030] Each armature winding 22 is composed of an insulated wire having a core wire made of a metal such as copper or aluminum and an insulating film covering the core wire. In this embodiment, each of the multiple armature windings 22 is a thin winding coil having a coil layer in which conductive wire is wound in a planar manner. Specifically, each of the multiple armature windings 22 is composed of, for example, one or more coil layers in which insulated wire is wound in a substantially fan shape when viewed from above. The multiple armature windings 22 configured in this way are arranged to surround the rotation axis 21 when viewed from the direction of the axis C of the rotation axis 21.

[0031] Each of the multiple armature windings 22 is connected to the commutator 30. Specifically, each of the multiple armature windings 22 is electrically connected to one of the multiple commutator segments 31 of the commutator 30.

[0032] Multiple armature windings 22 are covered with a molding resin 23 and molded together with the molding resin 23. The molding resin 23 is made of an insulating resin material such as phenolic resin or unsaturated polyester (BMC).

[0033] As shown in Figure 3, the commutator 30 is attached to the rotating shaft 21. Therefore, the commutator 30 rotates together with the rotating shaft 21 as the rotor 20 rotates. The commutator 30 attached to the rotating shaft 21 may be part of the rotor 20.

[0034] The commutator 30 has a plurality of commutator segments 31 arranged along the rotational direction of the rotating shaft 21. Specifically, the plurality of commutator segments 31 are arranged in a ring shape along the rotational direction of the rotating shaft 21 so as to surround the rotating shaft 21. Each commutator segment 31 It is an elongated member that extends in the longitudinal direction of the rotation axis 21.

[0035] Each of the multiple commutator segments 31 is a conductive terminal made of a metal material such as copper, and is electrically connected to the armature winding 22 of the rotor 20. The multiple commutator segments 31 are arranged in an insulated manner from each other, but are electrically connected by the armature winding 22 of the rotor 20. For example, two adjacent commutator segments 31 are electrically connected by the armature winding 22.

[0036] As an example, the commutator 30 is a molded commutator, and is constructed by molding a plurality of commutator segments 31 with a molded resin 32. In this case, the plurality of commutator segments 31 are embedded in the molded resin 32 so that their surfaces are exposed. The molded resin 32 is the commutator body and is a substantially cylindrical member having a through hole into which the rotating shaft 21 is inserted. The molded resin 32 is a resin molded body made of an insulating resin material such as a thermosetting resin.

[0037] As shown in Figure 3, two brushes 40 are in contact with the commutator 30. Specifically, each of the two brushes 40 is in contact with a commutator segment 31 of the commutator 30. As the commutator 30 rotates due to the rotation of the rotation shaft 21, the brushes 40 continuously make contact with all of the commutator segments 31 in sequence. Note that the number of brushes 40 is not limited to two; for example, there may be four.

[0038] As shown in Figure 4, the two brushes 40 are arranged in the brush holder 50. Specifically, each of the two brushes 40 is positioned in the brush holder 50 such that its longitudinal direction is perpendicular to the axis C of the rotation axis 21 (i.e., in the radial direction of rotation of the rotation axis 21).

[0039] In this embodiment, the angle between the two brushes 40 in the longitudinal direction is 180°. However, the angle between the two brushes 40 in the longitudinal direction may be less than 180°.

[0040] Each of the brushes 40 is a power supply brush (conducting brush) that supplies power to the armature winding 22 by contacting the commutator segment 31. The brush 40 includes a first end 41 that contacts the commutator 30 and a second end 42 located on the opposite side of the first end 41. The brush 40 is a conductive material. As an example, the brush 40 is a long, roughly rectangular carbon brush made of carbon. In this embodiment, the brush 40 may be a carbon brush containing a metal such as copper. This makes it possible to reduce the contact resistance between the brush 40 and the commutator segment 31. Such a brush 40 may contain, for example, graphite powder and copper powder It can be manufactured by kneading a binder resin and a hardening agent together, crushing the resulting mixture, compressing it into a rectangular prism shape, and then firing it.

[0041] As shown in Figures 3 and 4, the brush holder 50 has the same number of constant-load springs 110 as there are brushes 40. In this embodiment, two constant-load springs 110 are provided. The brushes 40 are mounted so as to be in constant contact with the commutator segments 31 of the commutator 30 by the pressing force from the constant-load springs 110. In other words, the brushes 40 are pressed against the commutator 30 by the constant-load springs 110.

[0042] As shown in Figure 3, the constant-load spring 110 applies pressure (spring pressure) to the brush 40 by its spring elastic force (spring restoring force), biasing the brush 40 toward the commutator 30. The configuration of the constant-load spring 110 will also be explained using Figure 5. Figure 5 is a perspective view showing the configuration of the constant-load spring 110 according to this embodiment. As shown in Figure 5, in this embodiment, the constant-load spring 110 is made of a strip-shaped wire and is a spring that presses the brush 40 against the commutator 30. In other words, the constant-load spring 110 is made of a long, thin plate. The constant-load spring 110 has a spiral portion 111 at one end where the strip-shaped wire is wound, a fixed portion 112 at the other end, and a flat portion 113 located between the spiral portion 111 and the fixed portion 112, where the strip-shaped wire has a planar shape. As shown in Figure 4, the spiral portion 111 is in contact with the second end portion 42 of the brush 40. The fixing portion 112 is fixed to the hook-shaped portion 60 of the brush holder 50. In this embodiment, the fixing portion 112 is fixed to the brush holder 50 by hooking the opening 117 (see Figure 5) formed in the fixing portion 112 onto the hook-shaped portion 60.

[0043] The hook-shaped portion 60, to which the fixing portion 112 of the constant-load spring 110 is hooked, is positioned near the first end portion 41 of the brush 40. As a result, the spiral portion 111 of the constant-load spring 110 pushes the second end portion 42 of the brush 40 in a direction that approaches the vicinity of the first end portion 41 of the brush 40 where the fixing portion 112 is positioned. Therefore, the pressing force from the constant-load spring 110 causes the first end portion 41 of the brush 40 to always be in contact with the commutator segment 31. In this way, the brush 40 is in continuous contact with the commutator segment 31, and as the commutator segment 31 rotates, it wears down due to friction. Therefore, the pressing force from the constant-load spring 110 causes it to move in the direction toward the axis C of the rotation shaft 21 (radial direction). For example, a metal material can be used as the material that constitutes the constant-load spring 110. In this embodiment, the constant-load spring 110 is made of austenitic stainless steel, which is a non-magnetic material.

[0044] The brushes 40 are supplied with power from an external power source located outside the electric motor 1. The external power source is a power source located outside the electric motor 1 and supplies a predetermined input voltage to the electric motor 1. In this embodiment, the external power source is a DC power source that supplies a DC 12V input voltage to the electric motor 1. The DC power source is not particularly limited as long as it is a power source that outputs DC power, for example, a generator, a converter, a battery, etc.

[0045] In the electric motor 1 configured as described above, the current supplied to each of the two brushes 40 flows as armature current (driving current) through the commutator segments 31 of the commutator 30 to the armature winding 22. This generates a magnetic flux in the rotor 20 (armature winding 22). The magnetic force generated by the interaction between this magnetic flux in the rotor 20 and the magnetic flux from the stator 10 becomes the torque that rotates the rotor 20. At this time, the direction in which the current flows is switched depending on the positional relationship when the commutator segments 31 of the commutator 30 and each of the two brushes 40 come into contact. By switching the direction in which the current flows in this way, a rotational force in a constant direction is generated by the repulsive and attractive magnetic forces between the stator 10 and the rotor 20, causing the rotor 20 to rotate around the rotation axis 21.

[0046] The brush holder 50 is a holding member that holds the two brushes 40. The brush holder 50 is made of, for example, an insulating resin material. In this embodiment, the brush holder 50 is a resin molded product formed by integral molding using a resin material. As shown in Figure 3, in this embodiment, the brush holder 50 is an outer shell member that constitutes the outer shell of the electric motor 1 and covers the second bracket 102 from the outside.

[0047] The brush holder 50 has a holder body 50a and a hook-shaped portion 60. The holder body 50a is the part of the brush holder 50 where the brushes are placed. In other words, the holder body 50a is the part of the brush holder 50 other than the hook-shaped portion 60. As shown in Figure 4, the holder body 50a of the brush holder 50 has two brush storage sections 51. A brush 40 is stored in each of the two brush storage sections 51. The brush storage sections 51 are formed in a concave shape on the inner surface side of the brush holder 50. In this embodiment, the brush storage sections 51 have a concave shape, but they may also have a box-like shape in which the brush storage sections 51 and the cover plate 131 are integrated. The hook-shaped portion 60 is the part that protrudes from the holder body 50a along the rotation axis 21 and is used to fix the constant load spring 110.

[0048] In this embodiment, the brush housing section 51 is elongated in a direction perpendicular to the axis C of the rotating shaft 21 (i.e., in the radial direction of rotation of the rotating shaft 21), and its cross-sectional shape is concave.

[0049] As shown in Figure 4, each of the two brush storage compartments 51, each containing a brush 40, is covered by a cover plate 131. The two cover plates 131 are made of, for example, brass plates, and each is positioned to cover the brush storage compartment 51.

[0050] As shown in Figure 4, the brush housing 51 houses the brush 40 along with the constant-load spring 110.

[0051] [2. Effects] Next, the effects of the electric motor 1 according to this embodiment will be explained using Figure 6. Figure 6 is an enlarged cross-sectional view of a part of the electric motor 1 according to this embodiment. In Figure 6, the constant load spring 110 and the armature winding 22 and their surroundings are shown in an enlarged view of the cross-section of the electric motor 1.

[0052] The armature winding 22 generates magnetic flux in the direction indicated by the block arrow in Figure 6. As mentioned above, the constant-load spring 110 is made of austenitic stainless steel, which is a non-magnetic material. However, when forming the spiral portion 111 of the constant-load spring 110 from a strip of austenitic stainless steel wire, the constant-load spring 110 becomes magnetic due to processing stress. Therefore, if there is no member to shield the magnetic flux between the constant-load spring 110 and the armature winding 22, the magnetic flux generated by the armature winding 22 will force the constant-load spring 110 toward the armature winding 22 (i.e., in the direction indicated by the dashed arrow in Figure 6). In other words, the constant-load spring 110 is attracted to the armature winding 22. In this case, the direction in which the constant-load spring 110 pushes the brush 40 may fluctuate, and the load may fluctuate.

[0053] In this embodiment, a second bracket 102 made of soft magnetic material is placed between the constant-load spring 110 and the armature winding 22, so that the magnetic flux generated by the armature winding 22 is shielded by the second bracket 102. Therefore, the magnetic flux generated by the armature winding 22 and reaching the constant-load spring 110 can be reduced. This suppresses the influence of the magnetic flux generated by the armature winding 22 on the constant-load spring. In other words, it is possible to suppress fluctuations in the direction in which the constant-load spring 110 pushes the brush 40, and fluctuations in the load.

[0054] Furthermore, in this embodiment, as shown in Figure 6, the fixed portion 112 and the flat portion 113 of the constant-load spring 110 are positioned on the opposite side of the brush 40 from the side where the multiple armature windings 22 are arranged. In other words, in Figure 6, the multiple armature windings 22 are positioned below the brush 40, while the fixed portion 112 and the flat portion 113 of the constant-load spring 110 are positioned above it. The closer the flat portion 113 of the constant-load spring 110 is to the multiple armature windings 22, the greater the force the flat portion 113 receives from the magnetic flux generated by the multiple armature windings 22. Therefore, when the flat portion 113 of the constant-load spring 110 is placed between the brush 40 and the multiple armature windings 22 (i.e., below the brush 40 in Figure 6), placing it on the opposite side of the brush 40 from where the multiple armature windings 22 are located reduces the force on the flat portion 113 due to the magnetic flux generated by the multiple armature windings 22. Consequently, the influence of the magnetic flux generated by the armature windings 22 on the constant-load spring 110 can be further suppressed.

[0055] (modified version) Although the electric motor relating to this disclosure has been described above based on embodiments, this disclosure is not limited to the embodiments described above.

[0056] For example, in the electric motor 1 according to the above embodiment, the second bracket 102 was made of a soft magnetic material, but other members arranged between the constant-load spring 110 and the multiple armature windings 22 may also be made of a soft magnetic material. For example, the cover plate 131 may be made of a soft magnetic material.

[0057] Furthermore, although the planar portion 113 of the constant-load spring 110 is positioned on the opposite side of the brush 40 from the side where the multiple armature windings 22 are arranged, the arrangement of the planar portion 113 is not limited to this. For example, as shown in Figure 7, the planar portion 113 may be positioned in the circumferential direction centered on the axis C of the rotation shaft 21 relative to the brush 40. Note that the arrow in Figure 7 indicates the circumferential direction centered on the axis C of the rotation shaft 21. Figure 7 is a plan view showing a modified arrangement of the constant-load spring 110 and the brush 40. Even with such an arrangement, it is possible to suppress the planar portion 113 of the constant-load spring 110 from being attracted by the magnetic flux generated by the armature windings 22.

[0058] Furthermore, although the stator 10 in the above embodiment was composed solely of permanent magnets, it is not limited to this. For example, the stator 10 may be composed of permanent magnets and an iron core, or it may be a stator consisting of stator windings and an iron core without using permanent magnets.

[0059] Furthermore, in the above embodiment, the electric motor 1 was a vehicle motor used in a vehicle, but it is not limited to this. The technology disclosed herein can also be applied to electric motors used in various other electrical devices, such as electric motors used in electric blowers mounted on vacuum cleaners, etc.

[0060] Here, an example of applying the electric motor 1 according to the above embodiment to an electric blower will be explained using Figure 7. Figure 8 is a perspective view showing a fan 190 attached to the electric motor 1 according to the above embodiment. Figure 9 is a schematic diagram of an electric blower 600 including the fan 190 attached to the electric motor 1. By attaching the fan 190 shown in Figure 8 to the rotating shaft 21 of the electric motor 1 according to the above embodiment, the electric blower 600 can be realized. In other words, the electric blower according to this disclosure comprises the electric motor 1 of the above embodiment and a fan 190 attached to the rotating shaft 21 of the electric motor 1. Note that the fan 190 shown in Figure 8 is just an example, and fans of other shapes and structures may be attached to the electric motor 1 according to the above embodiment. Since such an electric blower comprises the electric motor 1 according to the above embodiment, it will have the same effects as the electric motor 1 according to the above embodiment.

[0061] Furthermore, this disclosure also includes forms that can be obtained by applying various modifications to the above embodiments as conceived by those skilled in the art, and forms that can be realized by arbitrarily combining the components and functions of the embodiments and modified examples without departing from the spirit of this disclosure. [Industrial applicability]

[0062] The technology disclosed herein can be widely used in various products that incorporate electric motors, including products in the fields of automotive electrical systems and household electrical appliances. [Explanation of symbols]

[0063] 1 electric motor 10 Stator 11 Magnets 12 Air gap 12a Air gap surface 20 rotors 21 Rotation axis 21a First end 21b Second end 22 Armature winding 23, 32 Molding resin 30 commutator 31 Commutator piece 40 brushes 41 First end 42 Second end 50 Brush Holders 50a Holder Body 51 Brush storage section 60 Unicum 91 Bearing 101 First bracket 102 Second bracket 110 Constant load spring 111 Spiral section 112 Fixed part 113 Plane section 117 Aperture 131 Cover Plate 190 fans 600 electric blower

Claims

1. A rotor having a rotating shaft, A commutator attached to the rotor, A brush in contact with the commutator, Multiple armature windings connected to the commutator, A constant-load spring made of a strip-shaped plate material, which presses the brush against the commutator, The system comprises a soft magnetic member positioned between the plurality of armature windings and the constant-load spring, which shields the magnetic flux generated by the plurality of armature windings. Electric motor.

2. The constant-load spring has a spiral portion at one end around which the strip-shaped plate material is wound, a fixed portion at the other end, and a flat portion located between the spiral portion and the fixed portion, in which the strip-shaped plate material has a planar shape. The planar portion is positioned opposite to the plurality of armature windings when viewed from the brush, or in a circumferential direction centered on the axis of the rotation shaft relative to the brush. The electric motor according to claim 1.

3. The soft magnetic member is made of an iron plate. The electric motor according to claim 1 or 2.

4. The system further comprises a molded resin covering the plurality of armature windings. The electric motor according to any one of claims 1 to 3.

5. The thickness of the electric motor is smaller than the outer diameter of the electric motor. The electric motor according to any one of claims 1 to 4.

6. An electric motor according to any one of claims 1 to 5, A fan attached to the aforementioned rotating shaft, Electric blower.

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