JP2021040468A - Electric motor and electric apparatus - Google Patents

Abstract

To provide an electric apparatus, etc. which can detect a wear state of a current feeding brush without using an optical member and processing the current feeding brush.SOLUTION: An electric motor 1 comprises: a commutator 30 attached to a shaft 21 of a rotor 20; a first current feeding brush 41 and a second current feeding brush 42 each of which contacts the commutator 30; and a first additional brush 51 which contacts the commutator 30, in which the commutator 30 has a plurality of commutator segments 31 provided along a circumferential direction of the shaft 21, the first additional brush 51 is arranged to contact a commutator segment 31 immediately after the first current feeding brush 41 is detached among the plurality of commutator segments 31, the first additional brush 51 and the second current feeding brush 42 are constituted so that a first diode 81 and a first current detection circuit 91 exist on a wiring path between the first additional brush 51 and the second current feeding brush 42, and the first current detection circuit 91 detects magnitude of current flowing to the first diode 81.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to electric motors and electrical equipment.

Electric motors are used in various products such as electric blowers mounted on vacuum cleaners. As an electric motor, a commutator electric motor (commutator motor) that uses a brush and a commutator, or a brushless electric motor that does not use a brush and a commutator is known.

The commutator motor includes, for example, a stator, a rotor that is rotated by the magnetic force of the stator, a commutator attached to a rotating shaft (shaft) of the rotor, and an energizing brush that is in sliding contact with the commutator. The commutator has a plurality of commutator segments provided at equal intervals along the circumferential direction of the rotation axis of the rotor. A winding coil wound around the core of the rotor is electrically connected to each of the plurality of commutator segments.

Since the commutator rotates together with the rotor in a state where the energizing brush is in contact with the rotor, the energizing brush slides on the rotating commutator when the rotor rotates. At this time, since the energizing brush is in contact with the commutator segment in a pressed state, it gradually wears as the commutator rotates. Further, in the commutator motor, sparks may occur when the commutator segment and the energizing brush are separated by the rotation of the rotor.

In this way, the energizing brush is shortened not only by mechanical wear due to friction with the commutator segment but also by electrical wear due to sparks. If the energizing brush is worn and shortened, the energizing brush may need to be replaced or the commutator motor may become unusable.

Therefore, conventionally, an electric motor capable of detecting a wear state of an energizing brush by providing a detection device for measuring the remaining length of the energizing brush in a brush holder holding the energizing brush has been proposed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 5-74537

When installing a detection device and measuring the remaining length of the brush, for example, it is necessary to use an optical member such as an optical fiber for the detection device. In this case, dust of the energizing brush due to wear is applied to the optical member such as an optical fiber. Since it adheres and the detection accuracy of the detection device is lowered, the problem is that the operation reliability is lowered.

On the other hand, instead of using an optical member such as an optical fiber, a method of directly embedding a detection electrode for detecting the wear limit in the energizing brush is conceivable, but in this method, it is necessary to process the energizing brush. Therefore, the man-hours for processing the energizing brush becomes an issue.

The present disclosure has been made to solve such a problem, and includes an electric motor capable of detecting a wear state of the energizing brush without using an optical member or processing the energizing brush, and an electric motor thereof. The purpose is to provide electrical equipment.

In order to achieve the above object, one aspect of the electric motor according to the present disclosure is a rotor having a rotating shaft, a commutator attached to the commutator, a first energizing brush and a second energizing brush, each of which is in contact with the commutator. The commutator includes a current-carrying brush and a first commutator in contact with the commutator, and the commutator has a plurality of commutator segments provided along the circumferential direction of the commutator. Of the plurality of commutator segments, the first commutator brush is arranged so as to be in contact with the commutator segment immediately after the first energizing brush is separated, and the first additional brush and the second energizing brush are the first additional brush and the second energizing brush. The first diode and the first current detection circuit are configured to exist on the wiring path with the energizing brush, and the first current detection circuit detects the magnitude of the current flowing through the first diode.

Further, one aspect of the electric device according to the present disclosure is an electric device using the above-mentioned electric motor.

According to the present disclosure, it is possible to detect the wear state of the energizing brush without using an optical member or processing the energizing brush.

It is sectional drawing of the electric motor which concerns on embodiment. It is a figure which shows the connection relationship between the energizing brush and the additional brush in the electric motor which concerns on embodiment, and various circuits and electronic components. It is a figure for demonstrating how the energizing brush and the commutator segment are in sliding contact with each other due to the rotation of the commutator. It is a figure which shows the other connection relationship between the energizing brush and the additional brush in the electric motor which concerns on embodiment, and various circuits and electronic components. It is a figure which shows the connection relationship between the energizing brush and the additional brush in the electric motor which concerns on a modification, and various circuits and electronic parts.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below are specific examples 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 are 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, the same reference numerals are given to substantially the same configurations, and duplicate description will be omitted or simplified.

(Embodiment)
First, the overall configuration of the electric motor 1 according to the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the electric motor 1 according to the embodiment. FIG. 2 is a diagram showing a connection relationship between the energizing brush 40 and the additional brush 50 in the electric motor 1 and various circuits and electronic components. The cross-sectional view of the electric motor 1 in FIG. 2 shows a cross section taken along line II-II of FIG. 1, that is, a cross section when cut in a plane passing through the energizing brush 40 and the additional brush 50.

The electric motor 1 is a commutator electric motor, and as shown in FIGS. 1 and 2, the stator 10, the rotor 20 that rotates by the magnetic force of the stator 10, the commutator 30 attached to the shaft 21 of the rotor 20, and the commutator. An energizing brush 40 in contact with the child 30, an additional brush 50 in contact with the commutator 30, and a frame 60 for accommodating the stator 10 and the rotor 20 are provided.

The electric motor 1 in the present embodiment is a DC motor (DC motor) driven by direct current, and a magnet 11 is used as the stator 10 and an armature having a winding coil 22 is used as the rotor 20. ..

The electric motor 1 in this embodiment can be used for various electric devices. For example, the electric motor 1 can be used for an electric blower mounted on a vacuum cleaner, an air towel, or the like. Further, the electric motor 1 can also be used for an electric device, an electric tool, or the like mounted on an automobile. Hereinafter, each component of the electric motor 1 will be described in detail.

The stator 10 (stator) generates a magnetic force acting on the rotor 20. The stator 10 is configured such that N poles and S poles alternately exist on the air gap surface with the rotor 20 along the circumferential direction. In the present embodiment, the stator 10 is composed of a plurality of magnets 11 (magnets). The magnet 11 is a field magnet that creates a magnetic flux for generating torque, and is, for example, a permanent magnet having an S pole and an N pole. Each of the plurality of magnets 11 has an arc shape having a substantially constant thickness when viewed from above. The plurality of magnets 11 are fixed to the frame 60.

The plurality of magnets 11 constituting the stator 10 are arranged so that the north poles and the south poles are alternately and evenly present along the circumferential direction. Therefore, the direction of the main magnetic flux generated by the stator 10 (magnet 11) is the direction intersecting the direction of the axis C of the shaft 21. In the present embodiment, the plurality of magnets 11 are arranged at equal intervals along the circumferential direction so as to surround the rotor 20, and are located on the outer peripheral side of the rotor core 23 in the radial direction of the rotor 20. Specifically, a plurality of magnets 11 in which the north pole and the south pole are magnetized are arranged so that the center of the magnetic pole of the north pole and the center of the magnetic pole of the south pole are evenly spaced along the circumferential direction.

The rotor 20 (rotor) 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 the direction intersecting the direction of the axis C of the shaft 21. The rotor 20 has a shaft 21 which is a rotation shaft. Further, the rotor 20 is an armature and has a winding coil 22 and a rotor core 23. In the present embodiment, the rotor 20 is an inner rotor and is arranged inside the stator 10. Specifically, the rotor 20 is surrounded by a plurality of magnets 11 constituting the stator 10. Further, the rotor 20 is arranged with the stator 10 via an air gap. Specifically, there is a minute air gap between the outer peripheral surface of the rotor 20 (rotor core 23) and the inner surface of each magnet 11.

The shaft 21 is a rotating shaft having an axis C, and is a long rod-shaped member that serves as a center when the rotor 20 rotates. The longitudinal direction (extension direction) of the shaft 21 is the direction of the axis C (axis direction). The shaft 21 is rotatably held by a bearing such as a bearing. Although details are not shown, for example, the first end 21a, which is one end of the shaft 21, is supported by a first bearing held by a bracket fixed to the frame 60 or directly held by the frame 60. The second end 21b, which is the other end of the shaft 21, is supported by a second bearing held by a bracket fixed to the frame 60 or directly held by the frame 60. The bracket is fixed to the frame 60 so as to cover the opening of the frame 60, for example.

The shaft 21 is fixed to the center of the rotor 20. The shaft 21 is, for example, a metal rod, and is fixed to the rotor core 23 in a state of penetrating the rotor core 23. For example, the shaft 21 is fixed to the rotor core 23 by press-fitting or shrink-fitting into the center hole of the rotor core 23.

The winding coil 22 (rotor coil) is wound so as to generate a magnetic force acting on the stator 10 when an electric current flows. The winding coil 22 is wound around the rotor core 23 via the insulator 24. The insulator 24 is made of an insulating resin material or the like, and electrically insulates the winding coil 22 and the rotor core 23. The winding coil 22 is provided for each slot of the rotor 20 and is electrically connected to the commutator 30. Specifically, the winding coil 22 is electrically connected to the commutator segment 31 of the commutator 30.

The rotor core 23 is a laminated body in which a plurality of electromagnetic steel plates are laminated in the longitudinal direction of the shaft 21. The rotor core 23 has, for example, a plurality of teeth. A winding coil 22 is wound around each of the plurality of teeth. That is, a plurality of winding coils 22 are provided. The rotor core 23 is not limited to a laminated body of electromagnetic steel sheets, and may be a bulk body made of a magnetic material.

The commutator 30 is attached to the shaft 21. Therefore, the commutator 30 rotates together with the shaft 21 as the rotor 20 rotates. In this embodiment, the commutator 30 is attached to the first end 21a of the shaft 21.

As shown in FIG. 2, the commutator 30 has a plurality of commutator segments 31. The plurality of commutator segments 31 are provided along the circumferential direction of the shaft 21. Specifically, the plurality of commutator segments 31 are arranged in an annular shape at equal intervals so as to surround the shaft 21. In this embodiment, the commutator 30 has twelve commutator segments 31.

As shown in FIG. 1, each of the plurality of commutator segments 31 is a commutator piece extending in the longitudinal direction of the shaft 21. Each of the plurality of commutator segments 31 is a conductive terminal made of, for example, a metal material such as copper, and is electrically connected to the winding coil 22 of the rotor 20. As an example, the commutator 30 is a molded commutator, and a plurality of commutator segments 31 are resin-molded. In this case, the plurality of commutator segments 31 are embedded in the mold resin 32 so that the surface is exposed.

Further, although the plurality of commutator segments 31 are isolated from each other, at least two commutator segments 31 among the plurality of commutator segments 31 have the same potential (equal pressure) with each other by the pressure equalizing line. Is electrically connected to. Specifically, in the plurality of commutator segments 31, there are a plurality of sets of three or more commutator segments 31 having the same potential due to the pressure equalizing line. The pressure equalizing wire is integrally formed with a winding coil 22 (main winding) provided for each slot of the rotor 20. That is, the pressure equalizing wire and the winding coil 22 are a continuous continuous conductive wire without being cut in the middle.

The commutator 30 is in contact with the energizing brush 40 and the additional brush 50. Specifically, the energizing brush 40 and the additional brush 50 are in sliding contact with the commutator segment 31 of the commutator 30. Although not shown, the energizing brush 40 and the additional brush 50 are held by a brush holder. For example, the energizing brush 40 and the additional brush 50 are housed in the brush holder. In this case, the energizing brush 40 and the additional brush 50 slide inside the brush holder. Further, although not shown, the electric motor 1 is provided with a brush spring such as a coil spring or a torsion spring for pressing the energizing brush 40 and the additional brush 50 against the commutator 30. The brush spring applies pressure to the energizing brush 40 and the additional brush 50 by utilizing the elasticity of the spring. Each of the energizing brush 40 and the additional brush 50 is in a state where the surface of the tip portion is always in contact with the commutator segment 31 of the commutator 30 under the pressing force from the brush spring. The surface on which each of the energizing brush 40 and the additional brush 50 and the commutator segment 31 slide is a sliding surface. The brush spring is provided for each energizing brush 40 and for each additional brush 50, but the present invention is not limited to this.

The energizing brush 40 and the additional brush 50 are conductive conductors. As an example, the energizing brush 40 and the additional brush 50 are long, substantially rectangular parallelepiped carbon brushes made of carbon. Specifically, the energizing brush 40 and the additional brush 50 are carbon brushes containing a metal such as copper. For example, the energizing brush 40 and the additional brush 50 can be produced by crushing a kneaded product obtained by kneading graphite powder, copper powder, a binder resin, and a curing agent, compression molding into a rectangular parallelepiped, and firing.

The energizing brush 40 is a power feeding brush that supplies electric power to the rotor 20 by coming into contact with the commutator 30. Specifically, the tip portion of the energizing brush 40 comes into contact with the commutator segment 31 of the commutator 30. Therefore, an electric wire through which the current supplied from the power source 70 flows is connected to the energizing brush 40. For example, the energizing brush 40 is electrically connected to a power supply terminal that receives electric power from the power source 70 via an electric wire such as a pigtail wire. Specifically, the other end of the pigtail wire whose one end is connected to the electrode terminal is connected to the rear end of the energizing brush 40, and the energizing brush 40 comes into contact with the commutator segment 31. , The armature current supplied to the energizing brush 40 via the pigtail wire flows through each winding coil 22 of the rotor 20 via the commutator segment 31.

The energizing brush 40 is configured so that there is a state in which the energizing brush 40 is in contact with the two adjacent commutator segments 31. That is, the width of the energizing brush 40 in the rotation direction of the rotor 20 is larger than the length of the distance between the two adjacent commutator segments 31. As a result, the energizing brush 40 can short-circuit the winding coil 22 connected between the two commutator segments 31.

For example, as shown in FIG. 3A, when one energizing brush 40 is in contact with both of two adjacent commutator segments 31, the rotation of the rotor 20 advances the rotation of the commutator 30. As shown in 3 (b), the energizing brush 40 is separated from one of the two adjacent commutator segments 31 and rectifies the other of the two adjacent commutator segments 31 located behind in the rotational direction. It comes into contact with only the child segment 31. As a result, the winding coil 22 connected to the wiring path between the two adjacent commutator segments 31 can be short-circuited.

As shown in FIG. 2, in the present embodiment, a plurality of energizing brushes 40 are provided. Each of the plurality of energizing brushes 40 is in contact with the commutator 30. Specifically, the plurality of energizing brushes 40 include a first energizing brush 41 and a second energizing brush 42 as a pair of energizing brushes 40. The first energizing brush 41 and the second energizing brush 42 are arranged so as to sandwich the commutator 30. That is, the first energizing brush 41 and the second energizing brush 42 are arranged line-symmetrically about the axis C of the shaft 21. Each of the first energizing brush 41 and the second energizing brush 42 is in contact with the commutator segment 31 of the commutator 30 in a direction (radial direction) orthogonal to the axis C of the shaft 21. The first energizing brush 41 and the second energizing brush 42 are connected to the power supply 70. In the present embodiment, the power source 70 is a DC power source, and the first energizing brush 41 and the second energizing brush 42 are electrically connected via the power source 70 which is a DC power source. As an example, the first energizing brush 41 is an anode side brush connected to the anode side (positive electrode side) of the electrode 70 which is a DC power source, and the second energizing brush 42 is a cathode side (cathode side) of the power source 70 which is a DC power source. It is a cathode side brush connected to the negative electrode side).

The additional brush 50 is an auxiliary brush added to the energizing brush 40. In this embodiment, a plurality of additional brushes 50 are provided. Each of the plurality of additional brushes 50 is in contact with the commutator 30. Specifically, the plurality of additional brushes 50 include a first additional brush 51 and a second additional brush 52 as a pair of additional brushes 50. Each of the first additional brush 51 and the second additional brush 52 is in contact with the commutator 30.

The first additional brush 51 is arranged so as to be in contact with the commutator segment 31 immediately after the first energizing brush 41 is separated from the plurality of commutator segments 31. That is, the first additional brush 51 is arranged so as to be in contact with the commutator segment 31 in which the first energizing brush 41 is separated and sparks are generated.

Similarly, like the first additional brush 51, the second additional brush 52 is arranged so as to be in contact with the commutator segment 31 immediately after the second energizing brush 42 is separated from the plurality of commutator segments 31. That is, the second additional brush 52 is arranged so as to be in contact with the commutator segment 31 in which the second energizing brush 42 is separated and sparks are generated.

The energizing brush 40 and the additional brush 50 are arranged on the same plane. Specifically, the energizing brush 40 and the additional brush 50 are arranged on the same plane orthogonal to the direction of the axis C of the shaft 21. In the present embodiment, the first energizing brush 41, the second energizing brush 42, the first additional brush 51, and the second additional brush 52 are the same in the frame 60 without being displaced in the direction of the axis C of the shaft 21. It is arranged on a plane.

The first additional brush 51 and the second energizing brush 42 are configured such that the first diode 81 and the first current detection circuit 91 are present on the wiring path between the first additional brush 51 and the second energizing brush 42. ..

The first current detection circuit 91 detects the magnitude of the current flowing through the first diode 81. Specifically, the first current detection circuit 91 is caused by this spark when a spark occurs between the commutator segment 31 and the first energizing brush 41 immediately after the first energizing brush 41 is separated. The magnitude of the current flowing through the first diode 81 via the first additional brush 51 is detected. That is, the first current detection circuit 91 detects the magnitude of the current flowing through the first diode 81 by the arc voltage generated by the spark generated between the first energizing brush 41 and the commutator segment 31. At this time, the arc voltage due to the spark near the first energizing brush 41 is absorbed by the first diode 81. When this spark is generated, the first energizing brush 41 is on the low potential side, and the commutator segment 31 is on the high potential side.

The configuration of the first current detection circuit 91 is not particularly limited as long as it can detect the magnitude of the current flowing through the first diode 81. For example, the first current detection circuit 91 may be a circuit that detects the magnitude of the current using a pulse transformer, a circuit that detects the magnitude of the current using a photocoupler, or a circuit that detects the magnitude of the current. The circuit may be a circuit that detects the magnitude of the current using a resistor.

In the present embodiment, the first diode 81 and the first current detection circuit 91 are connected in series on the wiring path between the first additional brush 51 and the second energizing brush 42. Specifically, one of the first diodes 81 is connected to the first additional brush 51, and the other of the first diode 81 is connected to the first current detection circuit 91. Further, one side of the first current detection circuit 91 is connected to the first diode 81, and the other side of the first current detection circuit 91 is connected to the second energizing brush 42.

Since the second energizing brush 42 is connected to the cathode of the power source 70 which is a DC power source, the second energizing brush 42 reaches the second energizing brush 42 from the first additional brush 51 via the first diode 81 and the first current detection circuit 91. On the wiring path, there is a potential point set to a constant potential on the negative electrode side of the power supply 70, which is a DC power supply. Specifically, the constant potential on the negative electrode side of the power source 70, which is a DC power source, is the ground potential. That is, a circuit in which a ground potential exists on the wiring path from the first additional brush 51 to the second energizing brush 42 via the first diode 81 and the first current detection circuit 91, and the current of the first diode 81 is detected. Consists of a circuit having a ground potential.

Further, in the present embodiment, the first diode 81 and the first current detection circuit 91 are not built in the electric motor 1 but are arranged outside the electric motor 1. For example, the first diode 81 and the first current detection circuit 91 are incorporated together with the electric motor 1 in an electric device such as an electric blower on which the electric motor 1 is mounted.

Therefore, the electric motor 1 includes, as external connection terminals, a first additional brush connection terminal T51 connected to the first additional brush 51 and a second energization brush connection terminal T42 connected to the second energization brush 42. The first diode 81 and the first current detection circuit 91 are provided on the wiring path between the first additional brush connection terminal T51 and the second energizing brush connection terminal T42. Specifically, one of the first diodes 81 is connected to the first additional brush connection terminal T51, and the other side of the first current detection circuit 91 is connected to the second energizing brush 42.

The electric motor 1 in the present embodiment further includes a pair of first power supply terminals TP1 and second power supply terminals TP2 as external connection terminals connected to the power supply 70. The first power supply terminal TP1 is an anode-side power supply terminal connected to the anode of the power supply 70 which is a DC power supply, and the second power supply terminal TP2 is a cathode-side power supply terminal connected to the cathode of the power supply 70 which is a DC power supply. is there. The first power supply terminal TP1 is connected to the first energizing brush 41. That is, the anode of the power supply 70 and the first energizing brush 41 are connected via the first power supply terminal TP1. On the other hand, the second power supply terminal TP2 is connected to the second energizing brush 42. That is, the cathode of the power supply 70 and the second energizing brush 42 are connected via the second power supply terminal TP2.

Further, the first current detection circuit 91 is connected to the first brush damage determination circuit 101 that determines the damage of the first energizing brush 41. The first brush damage determination circuit 101 includes the commutator segment 31 and the first energization immediately after the first energization brush 41 is separated based on the magnitude of the current flowing through the first diode 81 detected by the first current detection circuit 91. The number of sparks generated between the brush 41 and the brush 41 is counted, and the damage of the first energizing brush 41 is determined based on the counted number of sparks. That is, the first brush damage determination circuit 101 counts the number of sparks generated between the commutator segment 31 and the first energizing brush 41 by the first current detection circuit 91, so that the first energizing brush 41 is in a worn state. To estimate.

For example, in the first brush damage determination circuit 101, when the number of counted sparks exceeds a preset threshold value (reference value), the first energization brush 41 is first energized until it reaches the state immediately before reaching the end of its life. It is determined that the brush 41 is damaged.

At this time, a signal indicating that the first energizing brush 41 is in a state immediately before reaching the end of its life is output from the first brush damage determination circuit 101 to the presentation unit 110. As a result, the presenting unit 110 presents to the user that the first energizing brush 41 is in a state immediately before reaching the end of its life.

The presentation unit 110 is, for example, a display device and / or an alarm device. That is, a character or an image indicating that the first energizing brush 41 is in the state immediately before reaching the end of its life is displayed on the display device, or a warning sound indicating that the first energizing brush 41 is in the state immediately before reaching the end of its life is emitted. It may be notified from the alarm device.

In the present embodiment, the first brush damage determination circuit 101 sets the threshold value for damage determination when the first energizing brush 41 is in a state immediately before reaching the end of its life, but the present invention is not limited to this. For example, the first brush damage determination circuit 101 may set the threshold value for damage determination when the first energizing brush 41 reaches the end of its life.

On the other hand, the second additional brush 52 and the first energizing brush 41 are configured so that the second diode 82 and the second current detection circuit 92 are present on the wiring path between the second additional brush 52 and the first energizing brush 41. ing.

The second current detection circuit 92 detects the magnitude of the current flowing through the second diode 82. Specifically, the second current detection circuit 92 is caused by this spark when a spark occurs between the commutator segment 31 and the second energizing brush 42 immediately after the second energizing brush 42 is separated. The magnitude of the current flowing through the second diode 82 via the second additional brush 52 is detected. That is, the second current detection circuit 92 detects the magnitude of the current flowing through the second diode 82 by the arc voltage generated by the spark generated between the second energizing brush 42 and the commutator segment 31. At this time, the arc voltage due to the spark near the second energizing brush 42 is absorbed by the second diode 82. When this spark is generated, the second energizing brush 42 is on the high potential side, and the commutator segment 31 is on the low potential side.

The configuration of the second current detection circuit 92 is not particularly limited as long as it can detect the magnitude of the current flowing through the second diode 82. For example, the second current detection circuit 92 may be a circuit that detects the magnitude of the current using a pulse transformer, or may be a circuit that detects the magnitude of the current using a photocoupler.

In the present embodiment, the second diode 82 and the second current detection circuit 92 are connected in series on the wiring path between the second additional brush 52 and the first energizing brush 41. Specifically, one of the second diodes 82 is connected to the first energizing brush 41, and the other of the second diode 82 is connected to the second current detection circuit 92. Further, one side of the second current detection circuit 92 is connected to the second diode 82, and the other side of the second current detection circuit 92 is connected to the second energizing brush 42.

In the circuit on the second current detection circuit 92 side, unlike the circuit on the first current detection circuit 91 side, the first additional brush 51 is passed from the first energizing brush 41 via the second diode 82 and the second current detection circuit 92. There is no potential point set to a constant potential on the negative side of the power supply 70, which is a DC power supply, on the wiring path up to. Specifically, the ground potential does not exist on the wiring path from the first energizing brush 41 to the second additional brush 52 via the second diode 82 and the second current detection circuit 92, and the second diode 82 The circuit that detects the current constitutes a floating circuit that does not have a ground potential.

Further, similarly to the first diode 81 and the first current detection circuit 91, in the present embodiment, the second diode 82 and the second current detection circuit 92 are not built in the electric motor 1 and are outside the electric motor 1. Have been placed. For example, the second diode 82 and the second current detection circuit 92 are incorporated together with the electric motor 1 in an electric device such as an electric blower on which the electric motor 1 is mounted.

Therefore, the electric motor 1 further serves as an external connection terminal with a second additional brush connection terminal T52 connected to the second additional brush 52 and a first energization brush connection terminal T41 connected to the first energization brush 41. Be prepared. The second diode 82 and the second current detection circuit 92 are provided on the wiring path between the second additional brush connection terminal T52 and the first energizing brush connection terminal T41. Specifically, one of the second diodes 82 is connected to the first energizing brush connection terminal T41, and the other side of the second current detection circuit 92 is connected to the second additional brush connection terminal T52. Since the first energizing brush 41 connected to the first energizing brush connection terminal T41 is connected to the anode of the power supply 70 which is a DC power supply, the second diode 82 is the first energizing brush connection terminal T41 and the first energizing brush connection terminal T41. 1 It is connected to the anode of the power supply 70, which is a DC power supply, via the power supply terminal TP1.

Further, the second current detection circuit 92 is connected to the second brush damage determination circuit 102 that determines the damage of the second energizing brush 42. The second brush damage determination circuit 102 includes the commutator segment 31 and the second energization immediately after the second energization brush 42 is separated based on the magnitude of the current flowing through the second diode 82 detected by the second current detection circuit 92. The number of sparks generated between the brush 42 and the brush 42 is counted, and the damage of the second energizing brush 42 is determined based on the counted number of sparks. That is, the second brush damage determination circuit 102 counts the number of sparks generated between the commutator segment 31 and the second energizing brush 42 by the second current detection circuit 92, so that the second energizing brush 42 is in a worn state. To estimate.

For example, in the second brush damage determination circuit 102, when the number of counted sparks exceeds a preset threshold value (reference value), the second energization brush 42 is energized until it reaches the state immediately before reaching the end of its life. It is determined that the brush 42 is damaged.

At this time, a signal indicating that the second energizing brush 42 is in a state immediately before reaching the end of its life is output from the second brush damage determination circuit 102 to the presentation unit 110. As a result, the presenting unit 110 presents to the user that the second energizing brush 42 is in a state immediately before reaching the end of its life. Specifically, as described above, since the presentation unit 110 is a display device and / or an alarm device or the like, characters or images indicating that the second energizing brush 42 is in a state immediately before reaching the end of its life are displayed on the display device. It is displayed, or a warning sound indicating that the second energizing brush 42 is in a state immediately before reaching the end of its life is notified from the alarm device.

In the present embodiment, the second brush damage determination circuit 102 sets the threshold value for damage determination when the second energizing brush 42 is in a state immediately before reaching the end of its life, but the present invention is not limited to this. For example, the second brush damage determination circuit 102 may set the threshold value for damage determination when the second energizing brush 42 reaches the end of its life.

As described above, in the electric motor 1 according to the present embodiment, the first additional brush 51 is arranged so as to be in contact with the commutator segment 31 immediately after the first energizing brush 41 is separated from the plurality of commutator segments 31. The 1 additional brush 51 and the 2nd energizing brush 42 are configured such that the 1st diode 81 and the 1st current detection circuit 91 are present on the wiring path between the 1st additional brush 51 and the 2nd energizing brush 42. ..

As a result, in the first additional brush 51, when the first energizing brush 41 and the commutator segment 31 are separated and a spark is generated between the first energizing brush 41 and the commutator segment 31, the arc voltage of the spark is generated. Will flow to the first diode 81 via the first additional brush 51. At this time, the magnitude of the current flowing through the first diode 81 is detected by the first current detection circuit 91. As a result, the wear state of the first energizing brush 41 can be detected based on the current detection result of the first current detection circuit 91. Therefore, the wear state of the first energizing brush 41 can be detected without using an optical member or processing the first energizing brush 41. That is, the life of the first energizing brush 41 can be detected.

In this case, in the present embodiment, the damage of the first energizing brush 41 is determined by using the first brush damage determination circuit 101. Specifically, the first brush damage determination circuit 101 counts the number of sparks based on the magnitude of the current flowing through the first diode 81 detected by the first current detection circuit 91, and determines the number of sparks counted. Based on this, the damage of the first energizing brush 41 is determined.

Further, in the electric motor 1 according to the present embodiment, not only the wear state of the first energizing brush 41 is detected, but also the arc voltage due to the spark generated between the first energizing brush 41 and the commutator segment 31 is first detected. It can be absorbed by the first diode 81 via the additional brush 51. That is, the first additional brush 51 and the first diode 81 are spark suppression components for suppressing sparks generated when the first energizing brush 41 and the commutator segment 31 are separated from each other.

By suppressing the sparks in the first energizing brush 41 in this way, it is possible to suppress the electrical wear of the first energizing brush 41 due to the sparks. As a result, the life of the first energizing brush 41 can be extended, that is, the life of the electric motor 1 can be extended. As a result, it is possible to set a high threshold value for the number of sparks in the first brush damage determination circuit 101, which is a criterion for determining that the first energizing brush 41 reaches the end of its life.

Further, in the electric motor 1 according to the present embodiment, the second additional brush 52 is arranged so as to be in contact with the commutator segment 31 immediately after the second energizing brush 42 is separated from the plurality of commutator segments 31. The 2 additional brush 52 and the 1st energizing brush 41 are configured such that the 2nd diode 82 and the 2nd current detection circuit 92 are present on the wiring path between the 2nd additional brush 52 and the 1st energizing brush 41. ..

As a result, in the second additional brush 52, when the second energizing brush 42 and the commutator segment 31 are separated and a spark is generated between the second energizing brush 42 and the commutator segment 31, the arc voltage of the spark is generated. The current due to the above will flow to the second diode 82 via the second additional brush 52. At this time, the magnitude of the current flowing through the second diode 82 is detected by the second current detection circuit 92. As a result, the wear state of the second energizing brush 42 can be detected based on the current detection result of the second current detection circuit 92. Therefore, the wear state of the second energizing brush 42 can be detected without using an optical member or processing the second energizing brush 42. That is, not only the life of the first energizing brush 41 but also the life of the second energizing brush 42 can be detected.

In this case, in the present embodiment, the damage of the second energizing brush 42 is determined by using the second brush damage determination circuit 102. Specifically, the second brush damage determination circuit 102 counts the number of sparks based on the magnitude of the current flowing through the second diode 82 detected by the second current detection circuit 92, and determines the number of sparks counted. Based on this, the damage of the second energizing brush 42 is determined.

Further, in the electric motor 1 according to the present embodiment, the arc voltage generated by the spark generated between the second energizing brush 42 and the commutator segment 31 can be absorbed by the second diode 82 via the second additional brush 52. it can. That is, the second additional brush 52 and the second diode 82 are spark suppression components for suppressing sparks generated by the separation of the second energizing brush 42 and the commutator segment 31.

By suppressing the sparks in the second energizing brush 42 in this way, it is possible to suppress the electrical wear of the second energizing brush 42 due to the sparks. As a result, the life of the second energizing brush 42 can be extended, that is, the life of the electric motor 1 can be extended. As a result, it is possible to set a high threshold value for the number of sparks in the second brush damage determination circuit 102, which is a determination criterion for the second energizing brush 42 to reach the end of its life.

(Modification example)
Although the electric motor 1 according to the present disclosure has been described above based on the embodiment, the present disclosure is not limited to the above embodiment.

For example, in the above embodiment, the first brush damage determination circuit 101 corresponding to the first current detection circuit 91 and the second brush damage determination circuit 102 corresponding to the second current detection circuit 92 are separately provided. The first brush damage determination circuit 101 and the second brush damage determination circuit 102 may be configured by one circuit. Specifically, as shown in FIG. 4, one brush damage determination circuit 103 common to the first current detection circuit 91 and the second current detection circuit 92 may be provided. The brush damage determination circuit 103 includes the commutator segment 31 and the first energizing brush 41 immediately after the first energizing brush 41 is separated based on the magnitude of the current flowing through the first diode 81 detected by the first current detecting circuit 91. The function of counting the number of sparks generated between the two and determining the damage of the first energizing brush 41 based on the counted number of sparks, and the function of flowing to the second diode 82 detected by the second current detection circuit 92. The number of sparks generated between the commutator segment 31 and the second energizing brush 42 immediately after the second energizing brush 42 is separated is counted based on the magnitude of the current, and the second is based on the counted number of sparks. It has a function of determining damage to the energizing brush 42.

Further, in the above embodiment, the first diode 81 and the first current detection circuit 91 are arranged outside the electric motor 1, but the present invention is not limited to this. Similarly, the second diode 82 and the second current detection circuit 92 are arranged outside the electric motor 1, but the present invention is not limited to this. Specifically, as in the electric motor 1A shown in FIG. 5, the first diode 81 and the first current detection circuit 91 and the second diode 82 and the second current detection circuit 92 are arranged inside the electric motor 1A. You may. That is, the first diode 81, the first current detection circuit 91, the second diode 82, and the second current detection circuit 92 may be built in the electric motor 1A.

Further, in the electric motor 1A shown in FIG. 5, the first brush damage determination circuit 101 connected to the first current detection circuit 91 and the second brush damage determination circuit 102 connected to the second current detection circuit 92 are the electric motor 1A. It is located outside, but it is not limited to this. Specifically, although not shown, the electric motor 1A may include a first brush damage determination circuit 101 and a second brush damage determination circuit 102. That is, the first brush damage determination circuit 101 and the second brush damage determination circuit 102 may be built in the electric motor 1A. It should be noted that these things can also be applied to the electric motor 1 shown in FIG.

Further, in the above embodiment, the stator 10 is composed of the magnet 11, but the stator 10 is not limited to this. For example, the stator 10 may be composed of a stator core and a winding coil wound around the stator core.

Further, in the above embodiment, the rotor 20 has a core, but the rotor 20 is not limited to this. That is, the electric motor 1 in the above embodiment can also be applied to a coreless motor having no core. For example, the electric motor 1 in the above embodiment can be applied to a coreless motor which is a flat flat motor in which the magnetic fluxes of the stator 10 and the rotor 20 are generated in the direction of the axis C of the shaft 21.

In addition, a form obtained by applying various modifications to the above embodiment that can be conceived by a person skilled in the art, or a form realized by arbitrarily combining the components and functions in the embodiment without departing from the gist of the present disclosure. Is also included in this disclosure.

The present disclosure can be used for various products equipped with an electric motor, such as a vacuum cleaner or an automobile.

1, 1A motor 10 stator 11 magnet 20 rotor 21 shaft 21a 1st end 21b 2nd end 22 winding coil 23 rotor core 24 insulator 30 commutator 31 commutator segment 32 mold resin 40 energizing brush 41 1st energizing brush 42nd 2 Energizing brush 50 Additional brush 51 1st additional brush 52 2nd additional brush 60 Frame 70 Power supply 81 1st diode 82 2nd diode 91 1st current detection circuit 92 2nd current detection circuit 101 1st brush damage judgment circuit 102 2nd Brush damage judgment circuit 103 Brush damage judgment circuit 110 Presentation unit

Claims (13)

A rotor with a rotating shaft and
With the commutator attached to the rotating shaft,
The first energizing brush and the second energizing brush, each of which is in contact with the commutator,
A first additional brush in contact with the commutator is provided.
The commutator has a plurality of commutator segments provided along the circumferential direction of the rotation axis.
The first additional brush is arranged so as to be in contact with the commutator segment immediately after the first energizing brush is separated from the plurality of commutator segments.
The first additional brush and the second energizing brush are configured such that a first diode and a first current detection circuit are present on a wiring path between the first additional brush and the second energizing brush.
The first current detection circuit detects the magnitude of the current flowing through the first diode.
Electric motor. The first additional brush connection terminal connected to the first additional brush,
A second energizing brush connection terminal connected to the second energizing brush is provided.
The first diode and the first current detection circuit are arranged outside the electric motor.
The first diode and the first current detection circuit are provided on a wiring path between the first additional brush connection terminal and the second energizing brush connection terminal.
The electric motor according to claim 1. The first current detection circuit is connected to a first brush damage determination circuit that determines damage to the first energizing brush.
The first brush damage determination circuit includes a commutator segment immediately after the first energizing brush is released and the first energizing circuit based on the magnitude of the current flowing through the first diode detected by the first current detecting circuit. The number of sparks generated between the brush and the brush is counted, and the damage of the first energizing brush is determined based on the counted number of sparks.
The electric motor according to claim 2. The first diode and the first current detection circuit are built in the electric motor.
The electric motor according to claim 1. Further, a first brush damage determination circuit connected to the first current detection circuit and determining damage to the first energizing brush is provided.
The first brush damage determination circuit includes a commutator segment immediately after the first energizing brush is released and the first energizing circuit based on the magnitude of the current flowing through the first diode detected by the first current detecting circuit. The number of sparks generated between the brush and the brush is counted, and the damage of the first energizing brush is determined based on the counted number of sparks.
The electric motor according to claim 4. Further, a second additional brush in contact with the commutator is provided.
The second additional brush is arranged so as to be in contact with the commutator segment immediately after the second energizing brush is separated from the plurality of commutator segments.
The second additional brush and the first energizing brush are configured so that a second diode and a second current detection circuit are present on the wiring path between the second additional brush and the first energizing brush.
The second current detection circuit detects the magnitude of the current flowing through the second diode.
The electric motor according to any one of claims 1 to 5. The second additional brush connection terminal connected to the second additional brush,
It is provided with a first energizing brush connection terminal connected to the first energizing brush.
The second diode and the second current detection circuit are arranged outside the electric motor.
The second diode and the second current detection circuit are provided on a wiring path between the second additional brush connection terminal and the first energizing brush connection terminal.
The electric motor according to claim 6. The second current detection circuit is connected to a second brush damage determination circuit that determines damage to the second energizing brush.
The second brush damage determination circuit includes a commutator segment immediately after the second energizing brush is released and the second energizing circuit based on the magnitude of the current flowing through the second diode detected by the second current detecting circuit. The number of sparks generated between the brush and the brush is counted, and the damage of the second energizing brush is determined based on the counted number of sparks.
The electric motor according to claim 7. The second diode and the second current detection circuit are built in the electric motor.
The electric motor according to claim 6. Further, a second brush damage determination circuit connected to the second current detection circuit and determining damage to the second energizing brush is provided.
The second brush damage determination circuit includes a commutator segment immediately after the second energizing brush is released and the second energizing circuit based on the magnitude of the current flowing through the second diode detected by the second current detecting circuit. The number of sparks generated between the brush and the brush is counted, and the damage of the second energizing brush is determined based on the counted number of sparks.
The electric motor according to claim 9. The first energizing brush and the second energizing brush are electrically connected via a DC power supply.
There is a potential point set to a constant potential on the negative electrode side of the DC power supply on the wiring path from the first additional brush to the second energizing brush via the first diode and the first current detection circuit. To do,
There is a potential point set to a constant potential on the negative electrode side of the DC power supply on the wiring path from the first energizing brush to the second additional brush via the second diode and the second current detection circuit. do not do,
The electric motor according to any one of claims 6 to 10. The constant potential on the negative electrode side of the DC power supply is the ground potential.
The electric motor according to claim 11. An electric device using the electric motor according to any one of claims 1 to 12.

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