JP2003324907A - Electric blower and vacuum cleaner using the same - Google Patents

Abstract

(57) [Problem] To provide an electric blower having a structure for immediately stopping the operation of a commutator motor when a brush overheats, and a vacuum cleaner using the same. SOLUTION: A temperature fuse 6 held by a fuse holder 11 is brought into contact with an opening end side of a brush holder 55 from which a brush 10 projects. Since the fuse holder 11 surrounds the periphery of the thermal fuse except for the surface in the direction of contact with the brush holder 55, the thermal fuse 6 is not affected by the air flowing through the motor, and the thermal fuse 6 detects the overheating state of the brush and blows. Then, the circuit connection to the field winding 54 and the armature winding 17 is cut off to stop the electric blower 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower using a commutator motor, and an electric blower having a protective structure in case the brush of the commutator motor falls into an abnormally overheated state, and the same. The present invention relates to an electric vacuum cleaner.

[0002]

2. Description of the Related Art A universal motor, which is an example of a commutator motor, is widely used as an electric motor applied to an electric blower, and it is easy to control the speed and has a high-speed rotation characteristic of a series-wound commutator motor. Is obtained, and the effect of compensating for the reduction of the air volume at low speed is obtained, and so on, it is suitable as an electric blower for an electric vacuum cleaner.

As is well known, the commutator motor energizes a plurality of armature windings from a brush that contacts a commutator that rotates with an armature, so that a plurality of commutator pieces arranged next to each other are adjacent to the commutator pieces. Sparks occur between the brush and the commutator at the moment when the short-circuit current flowing through the brush is cut off during matching. This spark increases abnormally even if one of the plurality of armature windings is broken. The sparks generate heat, and when the sparks increase abnormally, the brush becomes overheated and the life of the brush is significantly reduced.In addition, the carbon powder is hardened with a binder made of synthetic resin. If the silencer body surrounding the commutator motor is spread, the motor itself and the electric vacuum cleaner may catch fire.

The problem peculiar to such a commutator motor can be solved by stopping the operation of the commutator motor when the brush falls into an overheated state, and an overheat protection structure embodying this is provided. Various commutator motors have been proposed.

For example, in the technique (motor protection device) disclosed in Japanese Patent Application Laid-Open No. 2-26253, a thermal element detects an overheated state of a brush and activates a relay to shut off the power source of the motor. ing. Further, in the technique disclosed in Japanese Patent Publication No. 61-48359 (DC motor control device), temperature detectors are provided in the brush holder and the field winding respectively, and when the DC motor is overheated, The control circuit is configured to stop the operation of the DC motor. These prior-art techniques separately provide a relay and a control circuit that stop and control the operation of the electric motor when the overheated state of the brush is detected by the temperature sensor. On the other hand, a technique has been proposed in which the operation of stopping the operation of the commutator motor when the brush is overheated is performed by the power supply cutoff structure provided in the motor itself.

For example, in the technique disclosed in Japanese Utility Model Laid-Open No. 1-90264 and Japanese Utility Model Laid-Open No. 1-105359 (overheat protection device in a DC motor), the other end of the pigtail whose one end is joined to the brush is connected by a thermal fuse. When the temperature fuse fuses with the power supply terminal and the internal temperature of the motor rises, the spring pulling the other end of the pigtail pulls the other end of the pigtail away from the power supply terminal, cutting off the power supply to the armature. The motor is stopped.

Further, in the technique disclosed in Japanese Patent No. 3181182 (brush device for rotating electric machine), as shown in FIG. 8, the brush holder 43 holding the brush 44 is provided with the protection switch means 47, and the brush 44 When the temperature rises abnormally, the conduction circuit from the brush 44 to the stator winding is cut off to stop the operation of the electric motor. The protection switch means 47 is one in which the tip of the terminal fitting 50 connected to the stator winding is joined to the tip of the brush holder 43 by a conductor 51 such as solder. When the tip of the brush holder 43, which transfers heat quickly, is overheated, the conductor 51 is melted and the conduction between the terminal fitting 50 and the brush holder 43 is cut off. As a result, a circuit from the brush 44 to the stator winding is obtained. Is cut off and the motor stops.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the prior art disclosed as No. 82 (brush device for rotating electric machine), the conductor 51 forming the protection switch means 47 is made of solder or the like to attach the terminal fitting 50 to the brush holder 43.
Since it is joined to the terminal fitting 5 with a certain amount of conductor 51
It is difficult to bond 0 to the brush holder 43,
Since the joining state is also not constant, the temperature range in which the conduction between the terminal fitting 50 and the brush holder 43 is cut off by the melting of the conductor 51 is not constant, and a stable protection operation cannot be obtained. is there.

This problem is caused by the above-mentioned actual Kaihei 1-10535.
In the conventional technology disclosed as No. 9 (overheat prevention device in DC motor), the thermal fuse for joining the pigtail to the power supply terminal has the same problem. Although the substance is unknown, what is called a thermal fuse in this technology has a function of a thermal fuse and is considered as a solder because it is a bonding material. The low melting point alloy used for the thermal fuse has a composition similar to that of the solder, and the composition of the solder varies, but the Sn-Pb-Bi alloy has a composition ratio slightly lower than that of the low melting point alloy forming the thermal fuse. They are different but almost the same. Since it is used for joining in this conventional technique, the substance is solder, and it is necessary for the thermal fuse to have one product form.

Further, in the conventional technique disclosed as Japanese Patent No. 3181182 (brush device for rotating electric machine), air for cooling the internal components is circulated in the electric motor, and in particular, a fan is used in the blower electric motor. Since the air sucked in is exhausted through the electric motor, there is a flow of air that cools the brush device portion also in the component part of the protection switch means 47, and the protection switch means 47 is in an air-cooled state. Therefore, the conductor 51 exposed in the air flow path is cooled, and even if the brush 44 is overheated, it may not reach the melting temperature. Further, since the flow velocity and temperature of the air change depending on the rotation speed of the electric motor and the environmental temperature, the conductor 51 is not in a constant temperature responsive state, and there is a problem that a stable protection operation cannot be obtained.

Further, since the protection switch means 47 is joined to the brush holder 43, when the brush 44 is replaced, the protection switch means 47 is also replaced at the same time.
There is a problem that the cost for replacement increases.

The present invention was devised in view of the above problems of the prior art, and uses an electric blower capable of stably performing the operation of stopping the electric motor when the brush falls into an overheated state, and the same. The purpose is to provide a vacuum cleaner.

[0013]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a commutator motor for rotationally driving a fan, and a brush holder cylindrically formed of an electric conductor has one end protruding from its opening end. And a brush device urged so that one end of the brush is elastically contacted with the commutator, the field winding and / or the armature winding of the commutator motor are provided. A thermal fuse electrically connected in series with the brush holder is disposed on the opening end side of the brush holder with the outer casing abutting on the brush holder so that the thermal fuse is kept in contact with the brush holder. A fuse holder for holding the thermal fuse is provided so as to surround the periphery except the contact direction surface of the fuse holder.

According to the electric blower configured as described above, since the temperature fuse is held by the fuse holder and abuts on the opening end side of the brush holder, when the brush is overheated, the temperature of the overheated state is The heat is transferred to the thermal fuse at the closest position, and the thermal fuse melts and the field winding and /
Alternatively, the electric blower can be stopped by disconnecting the connection to the armature winding. Further, since the temperature fuse is surrounded by the fuse holder except for the surface in the direction of contact with the brush holder, the air sucked by the fan flows into the commutator motor and the temperature fuse is cooled and changes to the fusing temperature. Stable protection operation is performed without causing

In each of the above constructions, the thermal fuse is formed in the form of an electronic component in which the error of the fusing temperature is regulated within a predetermined range, so that the fusing temperature of the thermal fuse can be set accurately. Therefore, the electric motor can be surely stopped by the uniform fusing.

Further, the fusing temperature of the thermal fuse is set in consideration of the self-heating corresponding to the value of the current flowing through it, and the influence of the current flowing through the thermal fuse can be eliminated.

Further, a heat transfer plate having excellent heat conductivity is joined to the thermal fuse with a heat conductive adhesive, and the heat transfer plate is brought into contact with the opening end side of the brush holder, whereby the brush holder can be removed. The thermal conductivity to the thermal fuse can be improved, and the thermal fuse can be quickly melted when the brush becomes overheated.

Further, when the brush holder holding the brush is mounted on the commutator motor, the temperature fuse urged by the fuse holder comes into contact with the brush holder, so that the brush device and the temperature fuse are separate members. Therefore, there is no waste of replacing the thermal fuse at the same time when replacing the brush. To replace the brush, when the brush holder holding the brush is attached to the electric motor, the thermal fuse urged by the fuse holder contacts the brush holder.
The function of the thermal fuse is not impaired even if the brush is replaced.

Further, the second invention of the present application comprises an electric blower using a commutator motor, and a sponge-shaped silencer arranged so as to surround the commutator motor, and the commutator motor is tubular by a conductor. An electric blower using an electric blower, in which the formed brush holder is provided with a brush device in which one end of the brush protrudes from the opening end and the other end of the brush is elastically contacted with the commutator. In the vacuum cleaner, the electric blower is configured by using the electric blower according to the first invention.

According to the electric vacuum cleaner having the above structure, in the commutator motor of the electric blower applied to the electric vacuum cleaner, since the temperature fuse is held in the fuse holder and abuts on the opening end side of the brush holder, the brush is overheated. When it comes to a state,
The temperature of the overheated state transfers heat to the temperature fuse at the closest position, the temperature fuse is blown, and the connection to the field winding and / or the armature winding can be cut off to stop the electric blower. Further, since the temperature fuse is surrounded by the fuse holder except for the surface in the direction of contact with the brush holder, the air sucked by the fan flows into the commutator motor and the temperature fuse is cooled and changes to the fusing temperature. Stable protection operation is performed without causing Therefore, the resin component of the brush burns due to overheating of the brush,
It is possible to prevent it from spreading to the silencer surrounding the commutator motor, and to provide a function to prevent ignition of the vacuum cleaner due to failure of the commutator motor.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiments described below are examples of embodying the present invention and do not limit the technical scope of the present invention.

This embodiment shows an electric blower and an electric vacuum cleaner using the electric blower. The electric motor applied to the electric blower is configured as a single-phase series-wound universal motor which is an example of a commutator motor. .

FIG. 1 shows the construction of an electric blower 20 installed in an electric vacuum cleaner, which comprises a commutator motor 1 and a fan section 2. In the fan unit 2, as the centrifugal fan 7 that is rotationally driven by the commutator motor 1 rotates at high speed, as shown in FIG. 2, the electric vacuum cleaner 70 causes the suction cleaner 71 to connect the suction port 71 to the air containing dust. The air that has been sucked in and dust is separated by a filter or the like flows into the commutator motor 1 from the opening of the fan case 9 as a high-speed airflow. The air that has flowed into the commutator motor 1 cools the internal components and is exhausted.
It is discharged from the exhaust port 72 of 0 to the outside.

The commutator motor 1 includes a rotary shaft 15 supported by bearings 37 and 38, an armature core 16 fixed to the rotary shaft 15, and an armature winding 17 wound around the rotary shaft 15.
The armature 3 is configured by including the commutator 18, the field iron core 53 fixed inside the motor housing 8 so as to face the armature iron core 16, and the field winding 54 wound around the field iron core 53.
The field device 4 is configured to include the above, and the brush device 5 is configured by abutting the tip end portions of the brushes 10 on a plurality of commutator pieces 18a arranged side by side on the outer peripheral portion of the commutator 18. As shown in FIG. 3, the field magnet 4 has a field core 53 having a pair of field windings 54 having a two-pole structure and arranged in opposite directions with the armature 3 interposed therebetween, as shown in FIG. As described above, each field winding 54 is connected from the commutator 18 to the armature 3 through the brush 10, and the field winding 54 and the armature 3 are connected in series to form a series-wound motor.

The brush device 5, as shown in FIG.
A coil spring 56 is provided in a cylindrical brush holder 55.
The brush 10 is held in a state of being urged toward the opening end side of the brush holder 55, and the brush 10 is electrically connected to the brush holder 55 by a pigtail 57 formed of a flexible conductor. When the brush device 5 is attached to the motor housing 8 by the insulation holder 58, the tip of the brush 10 contacts the commutator piece 18a of the commutator 18, and the coil spring 56 biases the commutator piece 18a to elastically contact the commutator piece 18a. The obtained state is obtained. The brush device 5 can be replaced by attaching and detaching a screw 59 for fixing the insulating holder 58 to the motor housing 8.

The thermal fuse 6 is disposed by bringing the outer casing into contact with the open end side of the brush holder 55, and the thermal fuse 6 is fixed to a field holding body 60 for binding and holding the field iron core 53. It is held at 11. The fuse holder 11 is made of an insulating resin, covers the peripheral surface except the contact direction surface where the thermal fuse 6 abuts the brush holder 55 as shown in the figure, and the thermal fuse 6 is covered with the brush holder 55.
It keeps urging to the side.

The thermal fuse 6 applied in the present embodiment encloses a fusible alloy piece made of a low melting point alloy that melts at a predetermined temperature in an insulative exterior body, and a pair of fusible alloy pieces connected to both ends of the fusible alloy piece. The leads 6a and 6b are formed in the form of electronic components with leads, which are drawn out from both sides of the exterior body. The thermal fuse 6 is designed so that the fusible alloy piece melts when it reaches a set temperature, and is commercialized as an electronic component in which a melting temperature error (2 to 4 ° C.) is strictly defined. Therefore, it is possible to perform precise motor stop control as compared with the configuration such as the conductor 51 shown in the prior art in which the melting temperature greatly varies.

Further, since the operating current of the commutator motor 1 connected in series to the temperature fuse 6 flows, self-heating corresponding to the current value is generated, so that the fusing temperature is lowered.
The fusing temperature is set in consideration of the error.

As shown in FIGS. 3 and 5, one lead 6a of the thermal fuse 6 is guided into the concave portion of the connecting protrusion 61a formed on the insulating base 61, and also from one end of the field winding 54. The drawn field winding lead 54a is guided into the recess, and the connecting member 62 is press-fitted into the recess, whereby the lead 6a and the field winding lead 54a are fixed in pressure contact, and the temperature fuse 6 On the other hand, the lead 6a is connected to the field winding 54. The other lead 6b of the thermal fuse 6
Is connected to a connecting blade 63 fixed to the field holding body 60, and the connecting blade 63, when the brush device 5 is mounted,
Since the other lead 6b of the thermal fuse 6 is connected to the brush holder 55 because it is slidably inserted into the blade receiver 64 formed in the brush holder 55, the commutator 18 to the armature winding through the pigtail 57 and the brush 10. Connected to 17. That is, as shown in FIG. 4, the thermal fuse 6 is in a state of being connected in series between the field winding 54 and the armature winding 17 and the brush 10.

When the commutator motor 1 having the above structure is operated, the commutator 18 and the brush 10 in contact with the commutator 18 perform a rectifying action. A spark is generated between the brush 10 and the commutator 18 at the moment when the short-circuit current flowing through the brush 10 is cut off between adjacent brushes. Sparks have a fever, so
The temperature of the commutator 18 and the brush 10 rises, but in a normal state, since the air inside the electric motor is cooled by the air taken in by the fan unit 2 as described above, the temperature does not rise significantly. However, if a break occurs even in one of the armature windings 17, the amount of current increases and the sparks generated also increase. Increasing the spark increases the amount of heat generation and raises the temperature of the brush 10 and the commutator 18,
0 is overheated. The overheating of the brush 10 not only shortens the brush life, but the carbon brush may burn the synthetic resin binder that hardens the carbon powder due to overheating. When the muffler 73 arranged surrounding 1 is spread, the electric vacuum cleaner 70 itself may ignite.

When the brush 10 is overheated, heat is transferred to the brush holder 55 that surrounds and holds the periphery of the brush 10, and the open end side closest to the spark generation site is particularly susceptible to the overheated state of the brush 10. The thermal fuse 6 that is in contact with the opening end side of the brush holder 55 is blown when the temperature of the opening end side of the brush holder 55 exceeds a predetermined temperature, and the field winding 5
4 and the armature winding 17 are cut off from the current circuit, the commutator motor 1 is stopped. The temperature on the opening end side of the brush holder 55 rises after the temperature of the tip portion of the brush 10 in contact with the commutator piece 18a rises, so that the fusing temperature of the thermal fuse 6 exceeds the temperature of the tip portion of the brush 10. By setting the temperature slightly lower than the temperature, the operation of the commutator motor 1 can be stopped when the tip of the brush 10 becomes overheated.

As described above, since the air taken in by the fan portion 2 flows in the motor housing 8, if the temperature fuse 6 is exposed, it will be cooled by ventilation and the fusing operation will be delayed. Since the portion other than the contact direction surface with the brush holder 55 is covered with 11, the brush 10 is not affected by ventilation.
The fusing operation that corresponds to the temperature of is possible. Further, since the fuse holder 11 is made of resin, heat conduction from the thermal fuse 6 to the fuse holder 11 is small, and the fusing temperature of the thermal fuse 6 due to heat transfer from the thermal fuse 6 to the fuse holder 11 is affected. Is suppressed.

As shown in FIG. 6, the cross-sectional shape of the thermal fuse 6 can be formed in a rectangular shape, and can be brought into contact with the brush holder 55 by surface contact, so that the cylindrical shape of line contact is obtained. It is possible to detect the heat of the brush holder 55 more efficiently as compared with the thermal fuse 6 and to connect it to the fusing operation.

Further, as shown in FIG. 7A, the thermal fuse 6 is adhered to the brush holder 55 with a thermally conductive adhesive 66, so that the temperature on the open end side of the brush holder 55 is surely secured to the thermal fuse 6. Can be conducted to.
However, since the thermal fuse 6 is integrated with the brush device 5 by the heat conductive adhesive 66, there is a waste of replacing the thermal fuse 6 at the same time when the brush device 5 is replaced. Also,
It is necessary to provide a structure for connecting both leads 6a and 6b of the thermal fuse 6. Therefore, as shown in FIG. 7B, a heat transfer plate 67 formed of a metal plate having excellent heat conductivity is joined to the thermal fuse 6 by a heat conductive adhesive 66, and is transferred by the bias of the fuse holder 11. When the heating plate 67 is configured to contact the opening end side of the brush holder 55, the temperature of the brush holder 55 is efficiently detected by the temperature fuse 6, and when the brush 10 is overheated, the brush 10 is quickly blown to remove the commutator motor 1. The operation can be stopped.

In the configuration described above, the thermal fuse 6 is connected between the field winding 54 and the brush holder 55, but at a position where it is connected in series with the field winding 54 or the armature winding 17. Any of them can be used.

[0036]

As described above, according to the present invention, the overheated state of the brush is promptly detected and melted by the temperature fuse contacting the opening end side of the brush holder, and the operation of the commutator motor is stopped. Therefore, it is possible to prevent the life of the brush from being shortened due to the overheating of the brush, the spread of the electric blower, and the spread of the spread of the electric vacuum cleaner in which it is installed. Since the thermal fuse is manufactured as an electronic component by strictly controlling its fusing temperature,
The temperature setting for stopping the electric motor can be freely selected.

Further, since the temperature fuse is surrounded by the fuse holder except the surface in the direction of contact with the brush holder, it is suppressed that the temperature fuse is cooled by the air flowing in the commutator motor and is affected by the fusing temperature. . Since the fuse holder is biased so that the fuse remains in contact with the brush holder, the fuse is always in contact with the brush holder, and a stable overheat protection operation is performed.

Further, since the thermal fuse is biased by the fuse holder and disposed in contact with the brush holder, the brush device can be replaced without affecting the thermal fuse.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an electric blower according to an embodiment.
Sectional view.

FIG. 2 is a sectional view showing a configuration of an electric vacuum cleaner using the electric blower.

FIG. 3 is a plan view showing an internal configuration of a commutator motor.

FIG. 4 is a connection diagram of the commutator motor of the same.

FIG. 5 is a front view showing a lead wire connection structure.

FIG. 6 is a cross-sectional view showing a configuration in which the thermal fuse has a rectangular shape.

FIG. 7 is a cross-sectional view showing a configuration in which a thermal fuse is arranged via a heat conductive adhesive.

FIG. 8: 1 / showing the configuration of a commutator motor according to the prior art
2 sectional view.

[Explanation of symbols]

1 commutator motor 5 brush device 6 Thermal fuse 10 brushes 11 Fuse holder 17 Armature winding 18 commutator 20 electric blower 54 field winding 55 brush holder 66 Thermally conductive adhesive 67 Heat transfer plate 70 vacuum cleaner 73 silencer

Continued front page    (72) Inventor Akira Yamaguchi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3B006 AA00 FA01                 3H022 AA02 BA07 CA50 DA12 DA18                 5H611 AA01 AA03 BB04 PP01 QQ04                       SS02 UA01                 5H613 AA02 AA04 BB04 BB15 BB27                       GA13 GA14 GA17 GB08 GB09                       GB14 KK06 PP03 QQ06 QQ07                       RR05

Claims (6)

[Claims] 1. A commutator motor for rotationally driving a fan,
The brush holder is formed in a cylindrical shape by an electric conductor, the brush is held so that one end projects from the opening end, and the brush device is provided so as to urge the one end of the brush to elastically contact the commutator. In the electric blower, a temperature fuse electrically connected in series with the field winding and / or the armature winding of the commutator motor is disposed with the outer body in contact with the opening end side of the brush holder, In order to maintain the contact state of the temperature fuse with the brush holder, a fuse holder for holding the temperature fuse is provided around the periphery except the surface in the direction of contact with the brush holder. . 2. The electric blower according to claim 1, wherein the thermal fuse is formed in the form of an electronic component in which the error of the fusing temperature is restricted within a predetermined range. 3. The electric blower according to claim 1 or 2, wherein the fusing temperature of the thermal fuse is set in consideration of self-heating corresponding to the value of current flowing through it. 4. The heat transfer plate having excellent heat conductivity is joined to the thermal fuse with a heat conductive adhesive, and the heat transfer plate is brought into contact with the opening end side of the brush holder. The electric blower according to item 1. 5. The thermal fuse urged by the fuse holder contacts the brush holder when the brush holder holding the brush is mounted on the commutator motor. Electric blower described. 6. An electric blower using a commutator motor, and a sponge silencer arranged around the commutator motor, wherein the commutator motor is a brush holder formed of a conductor in a tubular shape. A vacuum cleaner using an electric blower, wherein a brush is held so that one end projects from the opening end, and a brush device is provided so that one end of the brush is elastically contacted with the commutator. An electric vacuum cleaner, wherein the blower has the configuration according to any one of claims 1 to 5.