JP2020137344A - Electric motor and electric blower - Google Patents

Abstract

To provide an electric motor and the like capable of suppressing sparks from occurring between the commutator and the brush.SOLUTION: An electric motor 2 includes: a rotor 10 with a rotating shaft 30; a commutator 40 attached to the rotating shaft 30; and a brush 50 in contact with a commutator 40. The brush 50 is composed of multiple division brushes divided by division planes having the axis of the rotary shaft 30 as a vertical line.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to an electric motor and an electric blower, and more particularly to a commutator electric motor with a brush (commutator motor) and an electric blower including the commutator electric motor.

Electric motors used in household vacuum cleaners include brushed commutator motors with brushes or brushless motors without brushes and commutators. Brushless motors have complicated structures, such as the need for electronic components and drive circuits to drive the motors, and the entire motor becomes expensive. Therefore, some vacuum cleaners use a commutator motor with a brush, which has a simpler structure and is cheaper than a brushless motor, to improve the performance.

In the commutator motor with a brush, the rectifying action is obtained by the brush and the commutator. In such a commutator motor with a brush, it is known that the brush vibrates abnormally, resulting in poor rectification or abnormal wear of the brush.

Therefore, conventionally, a technique has been proposed in which the vibration of the brush can be effectively and quickly attenuated to obtain good rectifying characteristics by dividing the brush at a dividing surface that intersects the rotation direction of the commutator. (Patent Document 1).

Japanese Unexamined Patent Publication No. 7-31101

In recent years, vacuum cleaners are required to be small and lightweight and to have improved suction capacity. For this reason, the commutator motor mounted on the vacuum cleaner is required to rotate at high speed in addition to being miniaturized and lightweight.

However, when the commutator motor is rotated at high speed, the seating property of the brush with respect to the commutator deteriorates, and the brush tends to vibrate. As a result, sparks are likely to occur between the commutator and the brush.

Further, when the dividing brush disclosed in Patent Document 1, that is, the brush divided into two dividing brushes at the dividing surface intersecting the rotation direction of the commutator, one brush jumps due to vibration or the like and is radial. If it is temporarily separated from the commutator to the outside, it will be rectified only by the other brush. As a result, rectification is insufficient and sparks are more likely to occur.

The present disclosure has been made to solve such a problem, and an object of the present invention is to provide an electric motor and an electric blower capable of suppressing the generation of sparks between the commutator and the brush.

In order to achieve the above object, one aspect of the electric motor according to the present disclosure includes a rotor having a rotating shaft, a commutator attached to the rotating shaft, and a brush in contact with the commutator. Is composed of a plurality of dividing brushes divided by a dividing surface having the axial direction of the rotation axis as a vertical line.

Further, one aspect of the electric blower according to the present disclosure includes the above-mentioned electric motor and a rotating fan attached to the rotating shaft included in the electric motor.

It is possible to suppress the generation of sparks between the commutator and the brush.

It is external perspective view when the electric blower which concerns on embodiment is seen from obliquely above. It is external perspective view when the electric blower which concerns on embodiment is seen from diagonally below. It is sectional drawing of the electric blower which concerns on embodiment. It is an enlarged perspective view of the main part which shows the structure of the electric motor which concerns on embodiment. It is a side view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on embodiment. It is sectional drawing which shows the structure of the brush and the brush box in the electric motor which concerns on embodiment. It is a vertical cross-sectional view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on embodiment. It is a cross-sectional view (cross-sectional view through the first division brush) which shows the brush and the peripheral structure of the brush in the electric motor which concerns on embodiment. It is a cross-sectional view (cross-sectional view through the second division brush) which shows the brush and the peripheral structure of the brush in the electric motor which concerns on embodiment. It is a figure which shows the current flow of a commutator piece when a rotor is rotating at a low speed in a commutator motor with a brush using an undivided brush. It is a figure which shows the current flow of a commutator piece when a rotor is rotating at a high speed in a commutator motor with a brush using an undivided brush. It is a figure which shows the current flow of the commutator piece in the commutator motor with a brush using the brush divided into two division brushes by the division plane intersecting with the rotation direction. It is a vertical cross-sectional view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on modification 1. FIG. It is a vertical cross-sectional view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on modification 2. FIG. It is a side view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on the modification 3. It is a side view which shows the brush and the peripheral structure of the brush in the electric motor which concerns on the modification 4. It is sectional drawing which shows the structure of the brush and the brush box in the electric motor which concerns on modification 5. FIG. It is sectional drawing which shows the structure of the brush and the brush box in the electric motor which concerns on modification 6. It is sectional drawing which shows the structure of the brush and the brush box in the electric motor which concerns on modification 7. FIG. It is sectional drawing which shows the structure of the brush and the brush box in the electric motor which concerns on modification 8.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that all of the embodiments described below show a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions of the components, connection forms, and the like shown in the following embodiments are examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present disclosure will be described as arbitrary components.

It should be noted that each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, substantially the same configuration is designated by the same reference numerals, and duplicate description will be omitted or simplified.

Further, in the present specification and drawings, the X-axis, the Y-axis, and the Z-axis represent the three axes of the three-dimensional Cartesian coordinate system. That is, the X-axis and the Y-axis are orthogonal to each other and both are orthogonal to the Z-axis. In the present embodiment, the Z-axis direction is the direction of the axis C of the rotating shaft 30.

(Embodiment)
[Composition of electric blower]
First, the overall configuration of the electric blower 1 according to the embodiment will be described with reference to FIGS. 1A, 1B, and 2. FIG. 1A is an external perspective view of the electric blower 1 according to the embodiment when viewed from diagonally above. FIG. 1B is an external perspective view of the electric blower 1 when viewed from diagonally below. FIG. 2 is a cross-sectional view of the electric blower 1 and shows a cross section when cut in a plane passing through the axis C of the rotating shaft 30. In addition, in FIG. 2, only the diagram which appears in the cross section is shown. The air flow described later is indicated by an arrow in FIG.

As shown in FIGS. 1A, 1B and 2, the electric blower 1 includes an electric motor 2 having a rotor 10 and a stator 20, a rotating fan 3 attached to a rotating shaft 30 of the electric motor 2, and a rotating fan 3. The air guide 4 into which the air discharged from the rotor flows, the fan case 5 that covers the rotary fan 3 and the air guide 4, and the frame 6 that houses the rotor 10 and the stator 20 are provided.

The electric motor 2 is a commutator electric motor (commutator motor) with a brush. Further, in the present embodiment, the electric motor 2 is a DC electric motor (DC motor) that receives a DC power supply as an input. As an example, the electric motor 2 is a fan motor that rotates a rotating fan 3. The detailed configuration of the electric motor 2 will be described later.

The rotary fan 3 sucks air into an outer housing (housing) composed of a fan case 5 and a frame 6. As an example, the rotary fan 3 is a centrifugal fan that can obtain a high suction pressure. Wind pressure is generated by the rotation of the rotary fan 3, air is sucked from the intake port 5a of the fan case 5, and 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 a metal material such as aluminum.

The air guide 4 has a plurality of diffuser blades arranged on the outer periphery of the rotary fan 3 as a guide plate for rectifying the flow of gas. For example, the air guide 4 rectifies the flow of air sucked from the intake port 5a of the fan case 5 by the rotation of the rotating fan 3 to generate a swirling flow, and the sucked gas smoothly flows into the frame 6. In this embodiment, the air guide 4 also functions as a bracket. The air guide 4 is arranged so as to cover the opening of the frame 6 leaving a ventilation path for sending the rectified air to the frame 6. The air guide 4 is made of, for example, a resin material, but may be made of a metal material.

The fan case 5 is a cover that covers the rotary fan 3. The fan case 5 is fixed to the frame 6. Further, the fan case 5 has an intake port 5a for sucking outside air. As the rotating fan 3 rotates, air flows into the fan case 5 from the intake port 5a of the fan case 5. The fan case 5 is made of, for example, a metal material, but may be made of a resin material. The fan case 5 is provided with a fan case spacer 7.

The frame 6 is a housing (case) for accommodating the electric motor 2. Specifically, the frame 6 is a bottomed tubular body having an opening. Further, a plurality of exhaust ports 6a are provided on the side wall on the bottom side included in the frame 6 in order to discharge the air sucked by the rotation of the rotary fan 3 to the outside. The frame 6 is made of, for example, a metal material, but may be made of a resin material.

In the electric blower 1 configured in this way, when the rotor 10 included in the electric motor 2 rotates, the rotating fan 3 rotates, and air is sucked into the fan case 5 from the intake port 5a of the fan case 5. As a result, air flows into the rotary fan 3, and the air sucked by the rotary fan 3 is compressed to a high pressure by the fan blades of the rotary fan 3 and discharged in the radial direction from the outer peripheral side portion of the rotary fan 3. It is guided to the outer peripheral portion of the fan case 5 by the diffuser blade of the air guide 4 surrounding the rotating fan 3, and becomes a swirling flow in the space between the air guide 4 and the fan case 5, and flows into the frame 6. The air that has flowed into the frame 6 is discharged to the outside of the electric blower 1 from the exhaust port 6a of the frame 6.

[Electric motor]
Next, the detailed configuration of the electric motor 2 will be described with reference to FIGS. 1A, 1B, and 2 with reference to FIG. FIG. 3 is an enlarged perspective view of a main part showing the structure of the electric motor 2 according to the embodiment.

As shown in FIGS. 2 and 3, the electric motor 2 is a commutator electric motor with a brush, and includes a rotor 10, a stator 20, a rotating shaft 30, a commutator 40, and a brush 50. The electric motor 2 in the present embodiment further includes a first bearing portion 61, a second bearing portion 62, a spring 70, a brush box 80, and a brush box holder 90.

The rotor 10 (rotor) has a rotating shaft 30 extending in the axis C direction. The rotor 10 rotates about the axis C of the rotating shaft 30 by the magnetic force of the stator 20. The rotor 10 in the present embodiment is an inner rotor, and is arranged inside the stator 20 as shown in FIG. Specifically, the rotor 10 is surrounded by the stator 20 with a minute air gap between the rotor 10 and the stator 20. The rotor 10 rotates at high speed, for example, at 40,000 rpm.

In the present embodiment, the rotor 10 is an armature and has a rotor core (rotor core) 11 and a winding coil 12 (rotor coil) wound around the rotor core via an insulator. In addition, in FIG. 2, the winding coil 12 is schematically shown. The rotor core 11 is a magnetic material made of a magnetic material. As an example, the rotor core 11 is a laminated body in which a plurality of electromagnetic steel sheets are laminated in the direction of the axis C of the rotating shaft 30 (axis direction). As a result of the current flowing through the winding coil 12 wound around the rotor core 11, a rotational force is generated in the rotor 10 by the interaction with the magnetic force generated by the stator 20, as will be described later.

The stator 20 (stator) generates a magnetic force acting on the rotor 10. In the present embodiment, the stator 20 is arranged so as to surround the rotor 10. The stator 20 may be composed of a stator core (stator core) and a winding coil (stator coil), and N poles and S poles are alternately and evenly present along the rotation direction of the rotor 10. It may be configured to do so. The stator 20 is fixed to the frame 6, for example.

The rotating shaft 30 is a shaft that serves as a center when the rotor 10 rotates. The rotating shaft 30 is, for example, a metal rod and is fixed to the rotor 10. Specifically, as shown in FIG. 2, the rotating shaft 30 is formed on the rotor core 11 in a state of penetrating the center of the rotor core 11 of the rotor 10 so as to extend to both sides of the rotor 10. It is fixed. The rotating shaft 30 is fixed to the rotor core 11 by press-fitting or shrink-fitting into the central hole of the rotor core 11.

The first portion 31 (output shaft), which is a portion on the output side of the rotary shaft 30, is a portion of the rotary shaft 30 that protrudes from the rotor core 11 toward the rotary fan 3. The second portion 32 (anti-output shaft), which is a portion on the counter-output side of the rotary shaft 30, is a portion of the rotary shaft 30 that projects from the rotor core 11 to the side opposite to the rotary fan 3 side. The first portion 31 is supported by the first bearing portion 61, and the second portion 32 is supported by the second bearing portion 62. As an example, the first bearing portion 61 and the second bearing portion 62 are bearings. In this way, the rotating shaft 30 is held by the first bearing portion 61 and the second bearing portion 62 in a rotatable state. A rotary fan 3 is attached to a portion of the first portion 31 that protrudes from the first bearing portion 61.

Further, as shown in FIGS. 2 and 3, the rotor 10 has a commutator 40. The commutator 40 is attached to a rotating shaft 30 included in the rotor 10. Therefore, the commutator 40 rotates together with the rotating shaft 30. In the present embodiment, the commutator 40 is attached to the first portion 31 (output shaft side) of the rotating shaft 30. Specifically, the commutator 40 is attached to a portion of the first portion 31 of the rotating shaft 30 between the rotor core 11 and the first bearing portion 61.

The commutator 40 is electrically connected to the winding coil 12 of the rotor 10. Specifically, the commutator 40 has a plurality of commutator pieces 41. As shown in FIG. 3, the plurality of commutator pieces 41 are arranged in an annular shape along the rotation direction of the rotation shaft 30 in a state of being insulated from each other. The plurality of commutator pieces 41 are electrically connected to the winding coil 12.

The brush 50 is in contact with the commutator 40. Specifically, the brush 50 is arranged so as to be slidable with the commutator piece 41 of the rotating commutator 40. The brush 50 is a power feeding brush, and when it comes into contact with the commutator piece 41, the rotor current is supplied to the winding coil 12 of the rotor 10 via the commutator piece 41. As shown in FIG. 3, a feeder line 53 is connected to the brush 50.

The brush 50 is composed of a pair of first brush 51 and second brush 52 arranged so as to sandwich the commutator 40. That is, the first brush 51 and the second brush 52 are arranged so as to face each other with the commutator 40 interposed therebetween.

In the electric motor 2 configured as described above, the current supplied to the brush 50 flows through the winding coil 12 of the rotor 10 via the commutator 40. As a result, in the electric motor 2, torque for rotating the rotor 10 is generated by the interaction between the rotor current and the magnetic flux generated from the stator 20. At this time, the current direction is switched by the commutator 40 and the brush 50, a rotational force in a fixed direction is generated, and the rotor 10 rotates.

Then, as the rotor 10 rotates, the rotating shaft 30 fixed to the rotor 10 rotates about the axis C. As a result, the rotary fan 3 attached to the rotary shaft 30 rotates.

[Brush and peripheral structure of brush]
Next, with reference to FIGS. 2 and 3, the details of the brush 50 used in the electric motor 2 according to the present embodiment and the peripheral structure of the brush 50 are shown in FIGS. 4, 5, 6, 7A and 7A. This will be described with reference to 7B.

FIG. 4 is a side view showing the brush 50 and the peripheral structure of the brush 50 in the electric motor 2 according to the embodiment. FIG. 5 is a cross-sectional view (YZ cross-sectional view) showing the configuration of the brush 50 and the brush box 80 in the electric motor 2. FIG. 6 is a vertical cross-sectional view (XZ cross-sectional view) showing the brush 50 and the peripheral structure of the brush 50 in the electric motor. 7A and 7B are cross-sectional views (XY cross-sectional views) showing the brush 50 and the peripheral structure of the brush 50 in the electric motor 2. In FIG. 6, only the brush 50, the spring 70, and the brush box 80 are shown in cross section. Further, FIG. 7A shows a cross section of the first brush 51 passing through the first divided brush 51a, and FIG. 7B shows a cross section of the first brush 51 passing through the second divided brush 51b.

As shown in FIGS. 2 and 3, the brush 50 is divided along the direction in which the commutator 40 rotates. Specifically, as shown in FIGS. 4 to 6, the brush 50 is composed of a plurality of divided brushes divided by a divided surface S whose vertical line is the axial center C direction of the rotating shaft 30. That is, the brush 50 is composed of a plurality of divided brushes arranged in the C direction of the axis C of the rotating shaft 30. The divided surface S for dividing the brush 50 into a plurality of parts is a surface substantially parallel to the rotating surface of the rotating shaft 30. Each of the plurality of divided brushes constituting the brush 50 is arranged in the axial center C direction of the rotation axis 30 with the divided surface S as a boundary.

In this embodiment, the brush 50 is composed of a pair of first brush 51 and second brush 52. Therefore, each of the first brush 51 and the second brush 52 is composed of a plurality of divided brushes. As shown in FIGS. 3 and 4, a feeder line 53 is connected to each of the plurality of divided brushes constituting the brush 50 for each divided brush.

As shown in FIG. 6, the first brush 51 is composed of two divided brushes, a first divided brush 51a and a second divided brush 51b, which are made of different materials. Similarly, the second brush 52 is composed of two split brushes, a first split brush 52a and a second split brush 52b, which are made of different materials.

The first split brushes 51a and 52a and the second split brushes 51b and 52b are both carbon brushes, but the first split brushes 51a and 52a have a higher metal content than the resin content. The brushes, the second divided brushes 51b and 52b, are carbon brushes in which the resin content ratio is larger than the metal content ratio. As the metal contained in the first divided brushes 51a and 52a and the second divided brushes 51b and 52b, for example, copper can be used.

Specifically, the first split brushes 51a and 52a are copper-rich carbon brushes mainly containing copper. The second split brushes 51b and 52b are resin-rich carbon brushes mainly containing a resin. Therefore, the copper-rich first split brushes 51a and 52a have lower resistance and the current easily flows as compared with the resin-rich second split brushes 51b and 52b. Further, the resin-rich second split brushes 51b and 52b have the characteristics of a resin, and have a smaller Young's modulus and are softer than the copper-rich first split brushes 51a and 52a.

The first split brushes 51a and 52a, which are copper-rich carbon brushes, are, for example, crushed a kneaded product obtained by kneading graphite powder, copper powder, a binder resin, and a curing agent, and compression-molded into a predetermined shape at 800 ° C. It can be produced by firing as described above. By firing at 800 ° C. or higher in this way, all the binder resin is carbonized, the resin component is eliminated, and the copper component is linked to reduce the resistance value. As such first division brushes 51a and 52a, for example, carbon brushes having a copper component of 30% and a carbon component of 70% can be used (resin component 0%).

Further, the second split brushes 51b and 52b, which are resin-rich carbon brushes, are obtained by, for example, crushing a kneaded product obtained by kneading graphite powder, a binder resin and a curing agent, and compression molding the mixture into a predetermined shape at 200 ° C. or higher. It can be produced by firing at 250 ° C. or lower. By firing at 200 ° C. or higher and 250 ° C. or lower in this way, the resin component can be left without carbonizing the binder resin. That is, the characteristics of the resin having rubber elasticity remain. As such the second split brushes 51b and 52b, for example, carbon brushes having a resin component of 20% and a carbon component of 80% can be used.

As shown in FIGS. 6, 7A and 7B, in the present embodiment, the first dividing brush 51a of the first brush 51 and the first dividing brush 52a of the second brush 52 sandwich the commutator 40. Facing each other. Further, the second split brush 51b of the first brush 51 and the second split brush 52b of the second brush 52 face each other with the commutator 40 in between. That is, the copper-rich carbon brushes face each other with the commutator 40 interposed therebetween, and the resin-rich carbon brushes face each other.

Each of the first division brushes 51a and 52a and the second division brushes 51b and 52b are elongated members, and are arranged so that their longitudinal directions are the radial directions of rotation of the rotation shaft 30.

Further, each of the first division brushes 51a and 52a and the second division brushes 51b and 52b are provided so as to be movable in the radial direction of rotation of the rotation shaft 30 and to be slidable with the commutator 40. In other words, each of the first division brushes 51a and 52a and the second division brushes 51b and 52b is in the radial direction from the outer circumference of the rotation axis 30 toward the axis C on the plane orthogonal to the axis C of the rotation axis 30. It is mounted so that it can be moved.

Specifically, as shown in FIGS. 2 to 4, each of the first dividing brushes 51a and 52a and the second dividing brushes 51b and 52b is pressed against the commutator 40 by the spring 70, and is pressed from the spring 70. It is in a state of being in constant contact with the commutator 40 under the pressing force of.

The spring 70 is, for example, a torsion spring having a coil portion and an arm portion. The spring 70 applies pressure (spring pressure) to the brush 50 by the spring elastic force (spring restoring force), and urges the brush 50 toward the commutator 40.

As shown in FIGS. 2 and 3, in the present embodiment, as the spring 70, the first spring 71 that presses the first split brush 51a and the second split brush 51b constituting the first brush 51 against the commutator 40, and It includes a first split brush 52a constituting the second brush 52 and a second spring 72 that presses the second split brush 52b against the commutator 40.

The first spring 71 is in contact with the rear end faces of each of the first split brush 51a and the second split brush 51b constituting the first brush 51. Specifically, the tip of the arm of the first spring 71 is provided with a contact portion 70a that contacts the rear end surfaces of the first split brush 51a and the second split brush 51b of the first brush 51. ..

Further, the second spring 72 is in contact with the rear end faces of each of the first split brush 52a and the second split brush 52b constituting the second brush 52. Similar to the first spring 71, the tip of the arm of the second spring 72 is provided with a contact portion 70a that contacts the rear end surfaces of the first split brush 52a and the second split brush 52b of the second brush 52. Has been done.

In the present embodiment, the contact portion 70a of the first spring 71 and the second spring 72 is a bent portion in which the tip portions of the first spring 71 and the second spring 72 are bent into a hairpin shape.

Due to the pressing force of the first spring 71 and the second spring 72, the front end faces (end faces on the commutator 40 side) of the first split brushes 51a and 52a and the second split brushes 51b and 52b are pressed against the commutator 40. are doing.

Further, as shown in FIGS. 6, 7A and 7B, in the present embodiment, the four division brushes 51a and 52a of the first division brush 51a and 52a and the four division brushes 51b and 52b of the second division brush have the same shape and the same size. Is. Therefore, in the first brush 51, the area of the end face on the commutator 40 side of the first split brush 51a is the same as the area of the end face on the commutator 40 side of the second split brush 51b. Similarly, in the second brush 52, the area of the end face on the commutator 40 side of the first split brush 52a is the same as the area of the end face of the second split brush 52b on the commutator 40 side.

The brush 50 configured in this way is covered with a brush box 80 as shown in FIGS. 2 to 6. The brush box 80 is a holding member that holds the brush 50. The brush box 80 is a housing for storing the brush 50. The brush box 80 is made of a metal material such as a steel plate or brass. As a result, the heat generated by the brush 50 due to energization can be efficiently dissipated.

In the present embodiment, the brush box 80 integrally holds the first brush box 81 that integrally holds the plurality of divided brushes constituting the first brush 51 and the plurality of divided brushes constituting the second brush 52. It has a second brush box 82 to hold. Specifically, the first brush box 81 houses the first divided brush 51a and the second divided brush 51b of the first brush 51, and the second brush box 82 is the first divided brush of the second brush 52. It houses 52a and the second split brush 52b.

The first brush 51 (first split brush 51a and second split brush 51b) pressed against the commutator 40 by the first spring 71 moves toward the commutator 40 in the first brush box 81 as the front end surface wears. Sliding. Similarly, the second brush 52 (the first split brush 52a and the second split brush 52b) pressed against the commutator 40 by the second spring 72 enters the commutator in the second brush box 82 as the front end faces wear. Slide toward 40.

As shown in FIGS. 2 and 3, the brush box 80 containing the brush 50 is further held by the brush box holder 90. In the present embodiment, the brush box holder 90 has a first brush box holder 91 for storing the first brush box 81 and a second brush box holder 92 for storing the second brush box 82.

The first brush box holder 91 and the second brush box holder 92 are fixed to the air guide 4. In the present embodiment, the first brush box holder 91 and the second brush box holder 92 are integrated with the air guide 4. That is, the first brush box holder 91 and the second brush box holder 92 are a part of the air guide 4. The first brush box holder 91 and the second brush box holder 92 may be separate from the air guide 4, or parts other than the air guide 4 (for example, when a bracket or the like is separately provided). May be fixed to the bracket or the like).

[Action effect, etc.]
Next, the action and effect of the electric blower 1 and the electric motor 2 according to the embodiment will be described with reference to FIGS. 8 to 10, including the background to the present disclosure. FIG. 8 is a diagram showing the current flow of the commutator piece 41 when the rotor is rotating at a low speed in a commutator motor with a brush using an undivided brush 50M. FIG. 9 is a diagram showing the current flow of the commutator piece 41 when the rotor is rotating at high speed in a commutator motor with a brush using an undivided brush 50M. FIG. 10 is a diagram showing the current flow of the commutator piece 41 in a commutator motor with a brush using a brush 50N divided into two dividing brushes 51N and 52N at a dividing surface intersecting the rotation direction. 8 to 10 show the direction and magnitude of the electric current.

In a commutator motor with a brush using an undivided brush 50M, when the rotor is rotated at a low speed, the current I1 of the flow shown in FIG. 8 flows through one commutator piece 41.

In recent years, brush-equipped commutator motors mounted on vacuum cleaners and the like are required to have high output by high-speed rotation in addition to miniaturization and weight reduction. In this case, in a commutator motor with a brush using an undivided brush 50M, when the rotor is rotated at high speed, a current I2 as shown in FIG. 9 flows through one commutator piece 41. In this case, sparks may occur between the commutator piece 41 and the brush 50M.

Moreover, when the rotor is rotated at high speed by the commutator motor with a brush, the seating property of the brush 50M with respect to the commutator 40 deteriorates, and the brush 50M easily vibrates. When the brush 50M vibrates in this way, sparks are more likely to occur between the commutator 40 and the brush 50M.

Further, in order to suppress the vibration of the brush 50N, as shown in FIG. 10, when the brush 50N divided into two divided brushes 51N and 52N at the dividing surface intersecting the rotation direction of the commutator 40 is used, one of them is used. When the split brush 51N jumps and temporarily separates from the commutator piece 41 outward in the radial direction, the rectification is performed only by the other split brush 52N. In this case, the area in contact between the commutator piece 41 and the brush 50N is halved, and the current I3 is cut off even though the rectification is not completed. As a result, as shown in FIG. 10, rectification is insufficient and a larger spark is generated.

As described above, in the conventional commutator motor with a brush, there is a problem that sparks are generated between the commutator and the brush, the brush is worn, and the life of the brush is shortened. That is, the life of the commutator motor with a brush is shortened. In addition, when sparks occur, the surface of the commutator piece may deteriorate. In this case, the brush is more likely to wear.

As a result of diligent studies by the inventors of the present application, they have found a technique capable of suppressing the generation of sparks between the commutator and the brush by devising the direction in which the brush is divided.

Specifically, as shown in FIGS. 4 to 6, the brush 50 used in the electric motor 2 in the present embodiment is divided by a plurality of divided surfaces S having the axial center C direction of the rotating shaft 30 as a vertical line. It is composed of split brushes. That is, the brush 50 is composed of a plurality of divided brushes arranged in the C direction of the axis C of the rotating shaft 30. Specifically, each of the first brush 51 and the second brush 52 is composed of a plurality of divided brushes divided by a divided surface S having the axial center C direction of the rotating shaft 30 as a vertical line.

With this configuration, even if any one of the plurality of dividing brushes constituting the first brush 51 (or the second brush 52) is separated from the commutator piece 41, the other dividing brush is a commutator piece. It is in contact with 41. As a result, the current is not interrupted during the rectification between each commutator piece 41 and the brush 50, so that the occurrence of sparks can be suppressed.

Moreover, by dividing the first brush 51 and the second brush 52 into a plurality of divided brushes, the vibration of the first brush 51 and the second brush 52 can be suppressed. As a result, it is possible to further suppress the occurrence of sparks.

Further, in the electric motor 2 of the present embodiment, the first brush 51 (or the second brush 52) is a plurality of divided brushes, the first divided brush 51a (or 52a) and the second divided brush, which are made of different materials. 51b (or 52b) and is included.

With this configuration, it is possible to realize a commutator motor suitable for purposes such as low voltage drive and high speed rotation. This point will be specifically described below.

The commutator motor with a brush is generally AC-driven, but as a commutator motor mounted on a vacuum cleaner or the like, a DC-driven commutator motor is also being studied. Since the commutator motor driven by direct current is driven by a low voltage, it is preferable to reduce the resistance of the brush. In this case, in the electric motor 2 of the present embodiment, it is conceivable to adopt a carbon brush containing a metal such as copper as a plurality of divided brushes constituting the first brush 51 and the second brush 52.

However, a metal-containing carbon brush has a higher Young's modulus and is harder than a metal-free carbon brush, and therefore tends to vibrate at high speed rotation. That is, if all of the split brushes constituting the first brush 51 and the second brush 52 are carbon brushes containing metal, sparks are likely to occur between the brushes and the commutator piece 41 brushes.

Therefore, in the electric motor 2 of the present embodiment, in the first brush 51 and the second brush 52, one of the two split brushes arranged in the axial C direction of the rotating shaft 30 contains more metal than the resin content ratio. A carbon brush having a larger ratio is used, and one of the two split brushes arranged in the C direction of the axis C of the rotating shaft 30 is a carbon brush having a resin content ratio higher than that of the metal content ratio.

Specifically, the first split brushes 51a and 52a are carbon brushes having a higher metal content than the resin content (that is, metal-rich carbon brushes), and the second split brushes 51b and 52b are used. , The carbon brush has a higher resin content than the metal content (that is, a resin-rich carbon brush).

With this configuration, in the metal-rich first split brushes 51a and 52a, the electric resistance of the carbon brush can be reduced by the metal to suppress the loss due to the brush voltage drop, and the resin-rich second split brushes 51b and 52b can be suppressed. Then, due to the elastic characteristics of the resin, the seating property of the carbon brush at the time of high-speed rotation can be secured and stable rectification can be ensured. Therefore, it is possible to realize a commutator motor with a brush that is driven at a low voltage and rotates at a high speed.

(Modification example)
The electric motor and the electric blower according to the present disclosure have been described above based on the embodiment, but the present disclosure is not limited to the above embodiment.

For example, in the above embodiment, in the first brush 51 and the second brush 52 facing each other with the commutator 40 in between, the first split brush 51a and the first split brush 52a, which are copper-rich carbon brushes, are rectified. The second split brush 51b and the second split brush 52b, which are resin-rich carbon brushes, face each other with the commutator 40 in between, but the present invention is not limited to this. Specifically, like the electric motor 2A shown in FIG. 11, the first split brush 51a of the first brush 51 which is a copper-rich carbon brush and the second split brush 51a of the second brush 52A which is a resin-rich carbon brush. The 52b faces the commutator 40 with the commutator 40 in between, and the second split brush 51b of the first brush 51, which is a resin-rich carbon brush, and the first split brush 52a of the second brush 52A, which is a copper-rich carbon brush. And may face each other with a commutator in between. The electric motor 2A shown in FIG. 11 uses a second brush 52A in which the vertical positions of the first divided brush 52a and the second divided brush 52b are reversed with respect to the electric motor 2 shown in FIG. ..

With the configuration of the electric motor 2A shown in FIG. 11, it is possible to suppress uneven wear of the commutator piece 41 due to the copper-rich carbon brush by the first brush 51 and the second brush 52A. That is, since the copper-rich carbon brush is harder than the resin-rich carbon brush, the amount of wear of the commutator piece 41 is large. In this case, as in the electric motor 2 shown in FIG. 6, when the copper-rich carbon brushes face each other and the resin-rich carbon brushes face each other with the first brush 51 and the second brush 52, the commutator piece In 41, there are a portion that only the copper-rich carbon brush contacts and a portion that only the resin-rich carbon brush contacts. As a result, the commutator piece 41 is unevenly worn. On the other hand, as in the electric motor 2A shown in FIG. 11, the first brush 51 and the second brush 52A are arranged at positions in which the copper-rich carbon brush and the resin-rich carbon brush are turned upside down. Since the copper-rich carbon brush and the resin-rich carbon brush alternately come into contact with the commutator piece 41 along the rotation direction, it is possible to prevent the commutator piece 41 from being unevenly worn. be able to.

Further, in the above embodiment, as shown in FIG. 6, the area of the end face on the commutator 40 side of the first split brushes 51a and 52a is the area of the end face of the second split brushes 51b and 52b on the commutator 40 side. It was the same, but not limited to this, even if the area of the end face on the commutator 40 side of the first split brushes 51a and 52a and the area of the end face of the second split brushes 51b and 52b on the commutator 40 side are different. Good. As a result, it is possible to meet the performance required by the electric motor.

For example, as in the electric motor 2B shown in FIG. 12, in the first brush 51B and the second brush 52B, the area of the end face on the commutator 40 side of the first divided brushes 51a and 52a (copper-rich carbon brush) is determined. It may be larger than the area of the end face on the commutator 40 side in the two-split brushes 51b and 52b (resin-rich carbon brush). With this configuration, the ratio of the copper-rich carbon brush having a low resistance becomes larger than the ratio of the resin-rich carbon brush, so that the resistance of the brush 50 can be reduced. Thereby, the voltage of the electric motor 2B can be lowered and the efficiency of the electric motor 2B can be improved.

Although not shown, conversely, the area of the end face on the commutator 40 side of the second split brushes 51b and 52b (resin-rich carbon brush) is rectified by the first split brushes 51a and 52a (copper-rich carbon brush). It may be larger than the area of the end face on the child 40 side. With this configuration, the ratio of the resin-rich carbon brush that retains the characteristics of the flexible resin becomes larger than the ratio of the copper-rich carbon brush, so that the brush 50 can be suppressed from jumping. Therefore, it is possible to further suppress the generation of sparks between the commutator 40 and the brush 50.

Further, in the above embodiment, as shown in FIG. 4, the contact portion 70a with the first brush 51 in the first spring 71 has a structure in which the tip portion of the first spring 71 is bent into a hairpin shape. Not limited to.

For example, as in the electric motor 2C shown in FIG. 13, the contact portion 70aC of the first spring 71C with the first brush 51 may be wound with the tip of the metal wire constituting the first spring 71C in a coil shape. Good. In this case, the contact portion 70aC of the first spring 71C may be in contact with the rear end faces of the first split brush 51a and the second split brush 51b. Although not shown, the contact portion of the second spring 72 with the second brush 52 may have the same structure.

Alternatively, as in the electric motor 2D shown in FIG. 14, the contact portion 70aD of the first spring 71D with the first brush 51 may be a plate member joined to the tip end portion of the first spring 71. In this case, the contact portion 70aD (plate member) of the first spring 71D may be in contact with the rear end surfaces of the first split brush 51a and the second split brush 51b. Although not shown, the contact portion of the second spring 72 with the second brush 52 may have the same structure.

Further, in the above embodiment, as shown in FIG. 4, the first spring 71 is in contact with the rear end surfaces of the first split brush 51a and the second split brush 51b constituting the first brush 51, and is also in contact with each other. The second spring 72 is in contact with the rear end faces of each of the first split brush 52a and the second split brush 52b constituting the second brush 52, but the present invention is not limited to this. That is, the pressure is applied to both of the two split brushes by one spring 70, but the present invention is not limited to this. For example, in order to apply pressure to one dividing brush by one spring 70, a plurality of springs 70 may be provided which press each of the plurality of dividing brushes constituting the brush 50 against the commutator 40. That is, the spring 70 may be provided in a one-to-one correspondence with a plurality of divided brushes constituting the brush 50. Specifically, four springs may be provided one-to-one with the four divided brushes constituting the brush 50. With this configuration, the four split brushes slide individually according to the amount of wear of each, so that the generation of sparks between the commutator 40 and the brush 50 can be further suppressed. Can be done.

Further, in the above embodiment, the first brush 51 is composed of two divided brushes, a first divided brush 51a and a second divided brush 51b, but the present invention is not limited to this. For example, as shown in FIG. 15, the first brush 51E may be composed of three divided brushes, a first divided brush 51a, a second divided brush 51b, and a third divided brush 51c. In this case, the three split brushes may be three types of carbon brushes each made of a different material, one type of carbon brushes each made of the same material, or two types. It may be a carbon brush of. The second brush 52 may also be composed of three divided brushes in the same manner.

Further, in the above embodiment, the first divided brush 51a and the second divided brush 51b constituting the first brush 51 are in contact with each other, but the present invention is not limited to this. For example, as shown in FIG. 16A, the first divided brush 51a and the second divided brush 51a and the second divided brush 51a are used by using the first brush box 81E provided with a partition wall between the first divided brush 51a and the second divided brush 51b. It may be configured so as not to come into contact with the dividing brush 51b. In the case of the first brush 51E composed of the first divided brush 51a, the second divided brush 51b, and the third divided brush 51c, as shown in FIG. 16B, there are three. A first brush box 81F in which a partition wall is provided between each of the divided brushes may be used. This may also be applied to the second brush 52 and the second brush box 82.

Further, as shown in FIG. 17, even if the first brush 51F is composed of four divided brushes, that is, the first divided brush 51a, the second divided brush 51b, the third divided brush 51c, and the fourth divided brush 51d. Good. In this case, the four split brushes may be four types of carbon brushes each made of a different material, one type of carbon brushes each made of the same material, or two types. Alternatively, it may be three types of carbon brushes. Further, also in this case, the first brush box 81 may be provided with a partition wall so that the adjacent divided brushes do not come into contact with each other. The second brush 52 may also be composed of four divided brushes in the same manner. Further, the first brush 51 and the second brush 52 may be composed of five or more divided brushes.

Further, when the first brush 51F composed of four divided brushes of the first divided brush 51a, the second divided brush 51b, the third divided brush 51c, and the fourth divided brush 51d is used, FIG. 18A shows. As shown, the first brush box 81G may be composed of two separable cases of two separate brush boxes 81a and 81b. Specifically, the first brush box 81G contains two separate brush boxes 81a for storing the first split brush 51a and the second split brush 51b, and the third split brush 51c and the fourth split brush 51d. It can be configured by a separate brush box 81b to be stored. In this case, as shown in FIG. 18B, the first brush box 81H may be composed of two separation brush boxes 81c and 81d, each having a partition wall. The configurations of the first brush boxes 81G and 81H can be similarly applied to the second brush box 82.

Further, in the above embodiment, the brush 50 is composed of two brushes 51 and a second brush 52 arranged at intervals of 180 degrees in the rotation direction, but the present invention is not limited to this. For example, the brush 50 may be composed of two brushes arranged at intervals of 120 degrees in the rotation direction. Further, the brush 50 may be composed of three or more brushes.

Further, the electric blower 1 in the above embodiment can be used for a vacuum cleaner, an air towel, or the like. Further, the electric blower 1 is not limited to a vacuum cleaner or an air towel, and may be applied to automobile equipment or the like, or may be applied to other household equipment or industrial equipment.

In addition, it is realized by arbitrarily combining the components and functions in each embodiment within the range obtained by applying various modifications to the above-described embodiment and the purpose of the present disclosure. Forms are also included in this disclosure.

The technique of the present disclosure is useful as an electric motor, an electric blower, etc., and can be widely used in various electric devices such as a vacuum cleaner.

1 Electric blower 2, 2A, 2B, 2C, 2D Electric motor 3 Rotating fan 4 Air guide 5 Fan case 5a Intake port 6 Frame 6a Exhaust port 7 Fan case spacer 10 Rotor 11 Rotor Iron core 12 Winding coil 20 Commutator 30 rotations Axis 31 1st part 32 2nd part 40 Commutator 41 Commutator piece 50, 50M, 50N Brush 51, 51B, 51E, 51F 1st brush 51a, 52a 1st division brush 51b, 52b 2nd division brush 51c 3rd division Brush 51d 4th split brush 51N, 52N Split brush 52, 52A, 52B 2nd brush 53 Feed line 61 1st bearing 62 2nd bearing 70 Spring 70a, 70aC, 70aD Contact 71, 71C, 71D 1st spring 72 2nd spring 80 brush box 81, 81E, 81F, 81G, 81H 1st brush box 81a, 81b, 81c, 81d Separation brush box 82 2nd brush box 90 brush box holder 91 1st brush box holder 92 2nd brush Box holder

Claims (11)

A rotor with a rotation axis and
With the commutator attached to the rotating shaft,
With a brush in contact with the commutator
The brush is composed of a plurality of divided brushes divided by a divided surface having a vertical line in the axial direction of the rotation axis.
Electric motor. Further, a brush box for integrally holding the plurality of divided brushes is provided.
The electric motor according to claim 1. The brush includes, as the plurality of division brushes, a first division brush and a second division brush made of different materials.
The electric motor according to claim 1 or 2. The first partition brush is a carbon brush in which the metal content ratio is larger than the resin content ratio.
The second split brush is a carbon brush in which the resin content ratio is larger than the metal content ratio.
The electric motor according to claim 3. The metal is copper,
The electric motor according to claim 4. The electric motor according to claim 4 or 5, wherein the area of the end face on the commutator side of the first split brush and the area of the end face on the commutator side of the second split brush are different. The brush is composed of a pair of first brush and second brush arranged so as to sandwich the commutator.
The electric motor according to any one of claims 3 to 6. The first division brush of the first brush and the first division brush of the second brush face each other with the commutator in between.
The second split brush of the first brush and the second split brush of the second brush face each other with the commutator in between.
The electric motor according to claim 7. The first split brush of the first brush and the second split brush of the second brush face each other with the commutator in between.
The second split brush of the first brush and the first split brush of the second brush face each other with the commutator in between.
The electric motor according to claim 7. It comprises a plurality of springs that press each of the plurality of split brushes against the commutator.
The electric motor according to any one of claims 1 to 9. The electric motor according to any one of claims 1 to 10.
A rotating fan attached to the rotating shaft of the electric motor,
To prepare
Electric blower.

Images