JP3524986B2 - Spark protection device for brushes for rotating electric machines - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC commutator motor, an AC commutator motor, or a brush that is in contact with a commutator of a brush device used in a rotating electric machine such as a generator. The present invention relates to a spark protection device for a rotating electric machine brush that prevents overheating due to an abnormal spark that occurs between.

[0002]

2. Description of the Related Art When a commutator motor is operated, a spark is inevitably generated between the commutator and the brush, but the steady spark does not cause the motor to burn.

However, for example, even one armature coil is broken, the commutator is eccentric to prevent the brush from properly contacting the commutator piece, or the brush causes chattering due to brush loss or abnormal wear. When the current suddenly stops flowing during rotation due to the above, a spark larger than the steady spark is abnormally generated between the commutator and the brush. If this abnormal spark goes around the commutator, the brush may be burned.

Therefore, in order to prevent an abnormal decrease in the brush life due to the heat of abnormal sparks, the temperature of the brush holder is detected by a temperature sensor, and the detection signal is processed by a signal processing circuit to detect the temperature sensor. A technique for stopping the rotation of the electric motor when the temperature becomes high is disclosed in Japanese Patent Laid-Open No. 5-1.
It is known from Japanese Patent No. 93147.

In addition to the above, in order to prevent abrasion and burnout of the electric motor due to excessive temperature rise of the brush, the temperature of the brush or brush holder is detected using a temperature sensor, and the temperature of the electric motor is detected based on the detected temperature. A technique similar to the above-mentioned publication for stopping rotation is disclosed in JP-A-6-14501 and JP-A-2.
-26253, Japanese Patent Publication No. 61-48359,
And known from JP-A-51-129601.

Further, in order to prevent abrasion of the brush during cooling operation, or to prevent abrasion of the brush due to excessive temperature rise, a thermal responsive element made of a shape memory alloy is used to operate the element. When a situation occurs, a technique of bringing the brush and the commutator into a non-contact state to stop the operation is disclosed in JP-A-5-300705 and JP-A-2-1772.
No. 82 publication and the like.

[0007]

These various techniques are effective as protection measures for electric motors.

However, the above-described various techniques for protecting the electric motor by using the temperature sensor require a signal processing circuit in addition to the temperature sensor. Since this circuit is configured by combining a large number of circuit components, there is a problem that the number of components of the entire protection device is large and the cost is high. Moreover, there is a problem that it is difficult to provide a high quality product because the operation reliability of the signal processing circuit is reduced depending on the number of the circuit components and the temperature sensor itself is varied. Further, since the temperature sensor has an insulating layer such as glass or ceramics and has a considerable heat capacity, it is disadvantageous in quickly following the rapid brush temperature rise caused by the abnormal spark and protecting the electric motor. There is also a problem.

Further, in the technique of using the heat responsive element made of a shape memory alloy instead of the temperature sensor, there is a problem that the shape memory alloy itself is a considerably expensive material, and therefore the cost is high. In addition, since the heat responsive element has a considerable heat capacity, it is disadvantageous in protecting the electric motor by quickly following the rapid temperature rise of the brush caused by the abnormal spark.

An object of the present invention is to provide an inexpensive spark protective device for a rotating electric machine, which can protect the brush with high reliability when an abnormal spark occurs between the commutator and the brush.

[0011]

DISCLOSURE OF THE INVENTION The present invention is premised on a brush for elastically pressing a rotating electric machine against a spark generated between a brush elastically pressed against a commutator of an armature and the commutator. .

In order to achieve the above object, the invention of claim 1 is provided so as to be electrically connected to a current path flowing through the armature, and is disposed near the commutator on the spark generation side. And a first terminal fitting having an electric connection part electrically connected to a current path flowing through the armature, and close to the electric connection part on the spark generation side near the commutator. a second terminal fitting having an electric connection portion which is disposed in a non-contact Te, the blanking
From the brush holder that guides the axial movement of the
The spa at the tip of the brush protruding toward the trowel side
Exposed to abnormal sparks facing the side of the stake
As described above, the thermal connection is provided between the both electric connecting portions and electrically connects the both electric connecting portions at a predetermined temperature or lower, and melts and disconnects the electric connection at a predetermined temperature or higher due to the thermal effect of the abnormal spark. It is characterized by consisting of a body. Similarly, the invention of claim 2 relates to the armature.
It is provided by being electrically connected to the current path
Is located on the spark generation side near the commutator.
Flow into the armature and the first terminal fitting having an electrical connection
It is provided by being electrically connected to the current path
In the vicinity of the commutator, the electric power is generated on the spark generation side.
Equipped with an electrical connection that is placed in contactless proximity to the air connection
The second terminal fitting and the electric connection part
If both of these electrical connections are electrically connected below a certain temperature
Together, this electrical connection is the thermal effect of the anomalous spark.
Due to the heat-sensitive fusing body that melts and cuts at a specified temperature
The brush within the first and second terminal fittings
One electrical connection located far away from the other electrical connection
It has springiness in the direction away from the
To the outer peripheral surface of the commutator of the one electrical connection portion.
The separation distance is less than that before the heat-sensitive melting body melts.
When the thermal cutout is blown out, make it larger.
It is characterized by that.

[0013]

The spark protection device according to the present invention forms a part of the current path flowing through the armature, and has the structure in which the first and second terminal fittings are electrically connected by the heat-sensitive melting member. It is equivalent to a switch that uses a child metal piece as a switch contact piece.
Then, at a temperature equal to or lower than the predetermined temperature, the heat-sensitive melting body does not melt, so that a state equivalent to closing the switch is maintained, so to speak, to secure a current path flowing through the armature. However, when the temperature exceeds a predetermined temperature, the heat-sensitive melting body melts, thereby cutting off the electrical connection between the two terminal fittings and, so to speak, opening the switch, so turning off the current in this spark protection device, Stop the operation of the rotating electric machine.

Since the electrical connection portion of the spark protection device is arranged in the vicinity of the commutator and on the spark generation side, it is more effective for abnormal sparks than when it is arranged at other positions. Can be exposed. Furthermore, as described above, the portion where the heat-sensitive melting member is provided between the electric connection portions of the pair of terminal fittings is separated from the brush and the brush holder to which it is in contact, and is thermally insulated from them.
There is no influence of resistance heating, frictional heat caused by sliding contact with the commutator, and temperature of the brush which is heated by the spark and rises in temperature.

Therefore, with the occurrence of the abnormal spark,
The temperature of the electrical connection part of both terminal fittings heated by this spark can be quickly raised, and the temperature difference of the electrical connection part where the heat-sensitive melting member is arranged can be used when a steady spark occurs and an abnormal spark occurs. You can make it bigger with and.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a side view showing a partial cross-section of the structure of an electric vacuum cleaner. In FIG. 1, reference numeral 1 denotes a cleaner body formed by connecting a lower case 1a and an upper case 1b, and the front of the lower case 1a. A lid 4 is mounted on the upper side of the portion to open and close a top opening of a dust collection chamber 3 formed in the front portion of the cleaner body 1 by rotating around a pivot portion 2.

A swingable front wheel 5 and a large-diameter rear wheel 6 are attached to the cleaner body 1, and the cleaner body 1 can be moved by rolling these. The cleaner body 1 is
It is routed through a dust suction hose (not shown) inserted and connected to a suction port (not shown) provided at the front end thereof.

Reference numeral 7 in FIG. 1 denotes a suction grid for partitioning the rear end of the dust collection chamber 3, and a filter 8 is supported on the front surface of the suction grid. The grid 7 supports a dust bag 9 connected to the suction port from the rear side through a filter 8. In addition, 10 in FIG.
Is an exhaust hole.

An electric blower 11 is housed in the cleaner body 1 between the suction grid 7 and the exhaust hole 10. The electric blower 11 includes a fan unit 12 and a one-way rotating AC commutator motor 13. The fan unit 12 includes a centrifugal fan (not shown) that is rotated by the commutator motor 13, a fan cover that covers the fan, and a commutation plate that guides the air discharged from the centrifugal fan into the commutator motor 13 while giving a diffuser effect. Be prepared.

The electric blower 11 is supported on the blower support walls 14 and 15 of the cleaner body 1 through the first rubber packing 16 in a vibration-proof manner, and the other members of the cleaner body 1 are also provided. The second rubber packing 1 is attached to the blower support wall 17.
It is built in the cleaner body 1 with its axis lined horizontally by being supported in a vibration-proof manner via 8. The arrangement of the electric blower 11 is not limited to the horizontal arrangement. For example, in the case of a pot type electric cleaner, the electric blower 11 is built in the cleaner main body with its axis line vertical. The ring-shaped first rubber packing 16 is fitted and arranged in the peripheral part of the fan cover, and the cap-shaped second rubber packing 18 is fitted and arranged in the rear end of the commutator motor 13. ing. The electric blower 11 sucks the air in the dust collection chamber 3 and discharges it from the commutator motor 13 to the outside.

In the main body 1 of the vacuum cleaner, there is housed a cylindrical silencer 19 which surrounds the commutator motor 13 once. The muffler 19 is made of a breathable synthetic resin such as urethane foam and is flammable. The air flowing out from the electric blower 11 flows through the muffler 19 in the rear portion of the cleaner body 1, and is discharged from the exhaust hole 10 to the outside of the cleaner body 1.

The structure of the commutator motor 13 will be described with reference to FIG. Reference numeral 21 in FIG. 2 is a substantially cylindrical frame with a bottom,
A bearing 22 is built in a bearing housing portion 21a projecting from the bottom wall and fitted with the second rubber packing 18. The fan cover is fitted and attached to the opening edge 21b of the frame 21, and the frame end plate 2
3 is attached. The end plate 23 is in the shape of a strip plate that traverses the opening of the frame 21 in the radial direction, and suction openings are formed between both side edges and the opening edge 21b.
A bearing 24 is built in a bearing housing portion 23a formed at the center of the frame end plate 23.

The rotating shaft 26 of the armature 25 is supported over the bearings 22 and 24, and the centrifugal fan (not shown) is attached to the end of the shaft 26 penetrating the bearing 24. The armature 25 includes a rotating shaft 26, an armature core 27 fitted and fixed to the rotating shaft 26, an armature coil 28 wound around the core 27, and a fixed commutator 29 fitted to the rotating shaft 26. The terminal portion of the armature coil 28 is connected to a plurality of commutator pieces 29a that are arranged in parallel with each other on the peripheral portion of the commutator 29 in an insulated state.

A plurality of discharge ports 38 (only one is shown in FIG. 2) are provided in the peripheral portion of the frame 21 on the bottom side. Located between the discharge port 38 and the opening edge 21b,
A stator 31 is built in the frame 21. This stator 31 has a substantially square outer shape when viewed from a plane,
It is provided by press-fitting the four corners into the inner peripheral surface of the frame 21,
A ventilation gap 32 (only one is shown in FIG. 2) is provided between the inner peripheral surface of the frame 21 and the side surface of the stator 31 opposed thereto.
Are formed.

A winding holder 33 made of synthetic resin and electrically insulating is attached to an end portion of the stator 31 located on the bottom side of the frame 21, and a pair of unillustrated members integrally formed with the holder 33. A terminal fitting 34 (see FIG. 3) is attached to the terminal block. The terminal portion of the stator coil 31a is electrically connected to the terminal fitting 34. The terminal fitting 34 has, in a part thereof, an electrical connection portion 34a formed by bending the end portion on the commutator 29 side at a right angle, for example. The connecting portion 34a is arranged in the vicinity of the commutator 29 and on the spark generation side between the commutator 29 and a brush described later, and is more than the tip of the brush holder 44 described later on the commutator side. It is close to the commutator 29.

A pair of brush devices 41 are attached to the peripheral wall of the frame 21 so as to penetrate the frame 21 in the radial direction. As shown in FIGS. 3 and 4, these brush devices 41 include a holder insulation 42, a brush holder 43, a brush 44, a pigtail 45, and a coiled spring 46.
And a terminal fitting 47.

More specifically, the holder insulation 42 has, for example, a melting point of
Molded with synthetic resin such as nylon with glass that has electrical insulation at 210 ℃. The holder insulation 42 has a holder insulation main body 42a penetrating the peripheral wall of the frame 21 and a mounting flange 42b. Mounting flange 42
Reference numeral b indicates an outer surface of the peripheral wall of the frame 21, and the holder insulation 42 is detachably fixed to the frame 21 by tightening a screw 48 penetrating the peripheral wall of the frame 21 and screwed into the peripheral wall. As shown in FIG. 3, the holder insulating body 42a is provided with a holder mounting hole 49 and a terminal mounting hole 50 penetrating in the axial direction thereof.

The brush holder 43 is made of brass or galvanized steel plate or copper plate, and has a pair of flat wall portions 43a, 43 facing each other as shown in FIG.
b and a pair of other wall portions 43c and 43d that face each other by connecting between the both wall portions 43a and 43b, respectively, and are formed in a rectangular tube shape with both ends open.

The brush holder 43 has a holder insulation 42.
It is inserted into the holder mounting hole 49 from the commutator 29 side and is mounted on the holder insulation 42 so as not to move in the axial direction. Reference numeral 43f in FIGS. 2 and 4 is a stopper cut and raised from the brush holder 43 and engaged with the holder insulating main body 42a.

As the brush 44 made of an electric conductor, a carbon brush in which carbon powder is bound with a binder made of a binder made of a synthetic resin and solidified into a prismatic shape is used. Brush 44
Is provided in the brush holder 43 so as to be movable in the axial direction using the holder 43 as a guide. One end of a pigtail 45 is embedded in the brush 44, and these are electrically connected.

As shown in FIG. 3, the terminal fitting 47 has a commutator 29 in the terminal mounting hole 50 of the holder insulating main body 42a.
It is attached by inserting it from the opening on the opposite side. The terminal fitting 47 includes a receiving portion 51 arranged to close an opening located outside the frame 21 in the holder mounting hole 49, and the terminal fitting 47 is bent from the receiving portion 51.
And a terminal main part 52 through which Incidentally, 52 in FIG.
a and 52b are the first and second pressure contact portions that are pressed against the inner surface of the terminal mounting hole 50 by the spring property of the terminal main portion 52, and 52c is engaged with the commutator side end surface of the holder insulating main body 42a. It is a cut-and-raised stopper tongue piece, and by these, the insertion state of the terminal fitting 47 into the holder insulation 42 is maintained.

The other end of the pigtail 45 is fixed to the receiving portion 51 by spot welding or the like, and the brush holder 43 and the brush 44 are electrically connected via the picktail 45.

Both ends of the spring 46 are in contact with the brush 44 and the receiving portion 51 and are housed in the brush holder 43.
The spring force of the spring 46 causes the brush 44 to move the brush 44 to the brush holder 43.
Is biased to project from the open end of the. Therefore, in the free state of the brush device 41, most of the brushes 44 are projected from the brush holder 43, and the brush device 4
In the state where 1 is fixed to the frame 21, the brush 44 hits the outer peripheral surface of the commutator 29 and is pushed into the brush holder 43 as shown in FIGS. 2 and 3, and is elastically pressed and held on the outer peripheral surface. .

The terminal fitting 47 electrically connected to the brush 44 as described above has an electric connecting portion 47a in a part thereof. The connecting portion 47a is formed by bending the end of the terminal main portion 52 opposite to the receiving portion 51. The electric connecting portion 47a is the electric connecting portion 34a.
Is provided in parallel with and in a non-contact manner with respect to the commutator 29.
Is arranged in the vicinity of and on the spark generation side between the commutator 29 and the brush 44.

The pair of terminal fittings 34, 47 are electrically connected by a conductive heat-sensitive melting member 53 provided between the electric connecting portions 34a, 47a. These terminal fittings 3
A spark protection device 54 that functions as a heat-sensitive switch is formed by the heat-sensitive melting body 53 and the heat-dissipating members 53.

The heat-sensitive melting member 53 is made of, for example, a low melting point metal such as solder (in this embodiment), a heat-melting synthetic resin having conductivity, or the same synthetic rubber. The melting point of the heat-sensitive melting member 53 made of solder or the like is lower than the melting point (210 ° C.) of the holder insulation 42 and is, for example, 180 ° C.
The heat-sensitive melting body 53 is solidified below its melting point and is inserted into the current path of the armature 25, so that the pair of terminal fittings 3
It is provided in order to electrically connect 4 and 47, and to melt the above-mentioned melting point to break the electrical connection between the terminal fittings 34 and 47.

The heat-melting / dissipating body 53 is formed by molding a certain amount of the heat-melting / melting material in advance into a predetermined shape, for example, a short columnar shape. It is melt-bonded to one of the two, electrically connected to the one electrical connection portion, and fixed in a heat conductive manner.

The other electric connection portion of the heat-sensitive melting member 53 is in close contact with the other end surface of the heat-melting member 53.
And the other electric connection portion are electrically connected. It should be noted that this close contact is made by inserting the brush device 41, to which the terminal fitting 47 is fixed in advance, into the frame 21 in which the terminal fitting 34 is already arranged from the outside and screwing it. Has become.

FIG. 5 is a diagram showing an electric circuit of the commutator motor 13. One brush device 41 pressed against the commutator 29 is provided with one stator coil 31 a of the stator 31. The other brush device 41 connected to one power supply terminal of the commercial AC power supply and pressed against the commutator 29 is connected to the other power supply terminal of the commercial AC power supply via the other stator coil 31a of the stator 31. It is connected. The electric motor 13 has a stator 31 that corresponds to the direction of current passed through the stator coil 31a every half cycle of alternating current.
The magnetic flux direction and the current direction of the armature 25 are switched in correspondence with each other, thereby continuing the rotation of the armature 25 in one direction. An arrow A in FIGS. 3 and 5 indicates the rotation direction of the armature 25.

In the first embodiment having the above-mentioned structure, the stator coil 31a of the stator 31 of the commutator motor 13 and the brush 44 elastically pressed against the commutator 29 include the spark protection device 54 and the pigtail 45. Are electrically connected via. The spark protection device 54 has a structure in which both the terminal fittings 43 and 47 are used as switch contact pieces, and is located near the commutator 29 as described above, and between the brush 44 and the commutator 29. It is located on the side where sparks occur in.

Therefore, at a temperature equal to or lower than a predetermined temperature (melting point of the heat-sensitive melting material 53), the heat-sensitive melting material 53 of the spark protection device 54.
Since it retains the preformed state, the terminal fittings 43, 47 forming the contact pieces of the two switches are formed through the fusing body 53.
The electrical connection portions 34a and 47a of are electrically connected. In other words, at a temperature equal to or lower than the predetermined temperature, the spark protection device 54, so to speak, maintains a state equivalent to closing the switch.

As a result, when the commutator motor 13 is energized, the current supplied from the power source is passed through the brush device 41 on the positive electrode side from the commutator 29 with which the brush 44 is in sliding contact with the armature coil. The commutator 29 drives the commutator 29 and a current is returned from the commutator 29 to the negative electrode side brush device 41, so that the commutator motor 13 is operated.

Since the centrifugal fan is rotated along with the operation of the commutator motor 13, the blowing operation by the electric blower 11 is carried out. As a result, dust can be sucked into the vacuum cleaner body 1 of the electric vacuum cleaner, and the wind discharged from the centrifugal fan is
Frame 2 through a straightening plate and a suction opening (not shown)
1, the stator 31 in this frame 21 after being introduced into
While passing through the ventilation gap 32 while air-cooling, and further after air-cooling the brush device 41, flows out through the discharge port 30 to the outside of the commutator motor 13. This wind noise is attenuated by passing through the silencer 19 surrounding the commutator motor 13. The air exhausted as described above is exhausted through the exhaust hole 10 of the cleaner body 1. Therefore, it is possible to perform cleaning with the electric vacuum cleaner under the above operating conditions.

During this operation, the short-circuit current flowing between the adjacent commutator pieces 29a of the commutator 29 via the brush 44 is cut off every time the commutation is performed, so that the brush 44 is removed each time.
A steady spark is generated between the commutator 29 and the commutator 29, and accordingly, the commutator 29 and the brush 44 or the brush holder 4
The temperature of 3 rises. The temperature of the brush 44 also rises due to resistance heat generated by energizing it.

Due to such temperature rise, the temperature of the brush 44 is transmitted to the brush holder 43 with which the brush 44 is in contact. However, the terminal fitting 34 electrically connected to the brush 44 is
The heat of the brush 44 and the brush holder 43 is applied to the terminal metal fitting 34 because it is thermally insulated by a (the partition 42c that partitions the holder mounting hole 49 and the terminal mounting hole 50 of the main body 42a). It is prevented from being transmitted. Moreover, the electrical connection portion 34 including the commutator-side tips of the terminal fittings 34 and 47 that are closest to the commutator 29.
a, 47a and the heat-sensitive melting member 53 sandwiched between them
Is disposed at a distance from the point where the steady spark is generated (the point where the short-circuit current is cut off) so as not to be directly exposed to the steady spark, and therefore the temperature rise of the spark protection device 54. , Especially its heat-sensitive melting member 5
The temperature rise of 3 is not so large.

By the way, for example, the armature coil 28
If even one is broken due to some reason, commutator 2
Since the value of the current cut by the rotation of 9 increases and the current ripple increases remarkably, the spark that occurs is also greatly abnormally generated, and of course, the thermal influence on the peripheral parts such as the brush 44 becomes great.

Due to such a situation, the electric connection portions 34a, 47a of the terminal fittings 34, 47 located closest to the commutator 29 on the spark generation side, which is the place where the temperature rises the fastest in the brush device 41, and these. The heat-sensitive melting body 53 during the period is effectively exposed to the abnormal spark, and the temperature rapidly rises. In other words, since the abnormal spark extends along the outer peripheral surface of the commutator 29, the area around the heat-sensitive melting member 53 is directly exposed to it, and the temperature of the heat-sensitive melting member 53 rapidly rises.

As a result, when the temperature of the heat-sensitive melting member 53 of the spark protector 54 becomes higher than a predetermined temperature, the heat-melting member 53 is melted and blown mainly from the side of the electric connecting portion 34a closest to the commutator 29. Child metal fittings 34, 4
The electrical connection between the electrical connection parts 34a and 47a of No. 7 is disconnected. In other words, the current path flowing through the armature 25 in the spark protection device 54 is cut off, so to speak, the switch is opened.

As described above, according to the commutator motor 13 including the spark protection device 54 having the above-described structure, the temperature of the heat-melting and melting body 53 rapidly reaches a predetermined temperature or more due to the occurrence of abnormal spark, Since the current path flowing through the armature 25 can be quickly cut by the spark protection device 54, the further continuous operation of the commutator motor 13 can be stopped.
The temperature of the brush 44 does not rise abnormally due to the abnormal spark between the commutator 29 and the brush 44.

As a result, there is no risk that the synthetic resin component forming the binder of the brush 44 will burn to cause smoke or ignition. Therefore, the flame of the brush 44 does not spread to the flammable silencer 19 through the discharge port 38. In other words, the spark protection device 54 can promptly protect the commutator motor 13 and the cleaner body 1 incorporating the commutator motor 13 from the risk of burning due to an abnormal spark.

Further, in the structure of the present embodiment, since the block formed in advance in the predetermined shape is adopted as the heat-sensitive melting member 53 of the spark protection device 54, this melting member 53 is connected between the electrical connecting portions 43a and 47a. As compared with a case where solder is piled up, it is possible to easily and reliably control the amount of the heat-sensitive fusing body 53 and improve mass productivity.

As described above, in combination with the fact that the temperature difference around the heat-sensitive melting member 53 can be increased between the occurrence of a steady spark and the occurrence of an abnormal spark, the amount of solder or the like forming the heat-sensitive melting member 53 can be used. Therefore, the variation in temperature at which the heat-sensitive melting body 53 melts can be reduced, and accordingly, the spark protection device 53 can perform the protection operation with high reliability.

Further, the spark protection device 54 having the above structure
Since the above-described protection operation is obtained, the temperature sensor for obtaining the same protection operation and the accompanying signal processing circuit having a large number of parts are not required. Therefore, the number of parts is small, the structure is simple, the device can be operated with high reliability, and a cost-effective shape memory alloy is not used to obtain the same protection operation, so that it can be provided at low cost.

Moreover, since the melting point of the holder insulation 42 is higher than the melting point of the heat-sensitive fusing body 53, the holder insulation 42 is heated by heat.
It is possible to open the current path flowing to the armature 25 by melting the heat-sensitive melting member 53 before the deformation occurs. As a result, the mutual positional relationship of the respective parts of the spark protection device 54 does not change from the proper state due to the deformation of the holder insulation 42 such that it melts under the influence of heat, so the protection operation of the spark protection device 54 is ensured. You can run it.

FIG. 6 shows a second embodiment of the present invention.
The second embodiment differs from the first embodiment only in the structure around the electrical connecting portions of both terminal fittings. Other configurations are the same as or similar to those of the spark protection device for a rotating electric machine brush according to the first embodiment shown in FIGS. 1 to 5, including portions not shown in FIG. 6. 1 to 5 are substituted, and the same or similar components shown in the drawings are denoted by the same reference numerals as those in the first embodiment, and a description of those components and an explanation of the action and effect based thereon will be omitted. However, these same or similar parts also form part of the apparatus of this embodiment.

In the second embodiment, the electric connecting portion 47a of the terminal fitting 47 is not a bent portion at a right angle,
It is formed by a flat tip portion that extends parallel to the axial direction of the brush holder 43 and is closest to the commutator 29. One end surface of the heat-sensitive melting member 53 preformed in the electric connecting portion 47a is melt-bonded by pressure welding such as ultrasonic welding.

The electrical connection portion 34a of the terminal fitting 34 is also not a bent portion at a right angle, but is formed of a flat tip portion that extends parallel to the axial direction of the brush holder 43 and is closest to the commutator 29. The terminal fitting 34 is made of spring steel, and in particular, has a distal end portion 34b having an electrical connection portion 34a.
As shown by the chain double-dashed line in FIG. 6, in the free state, it comes close to the connection part 47a side without contacting the electric connection part 47a of the terminal fitting 47.

With the attachment of the brush device 41 to the frame 21, the heat-sensitive melting member 53 previously melt-bonded to the electric connecting portion 47a changes the tip end side portion 34b from the two-dot chain line state to the state shown by the solid line. It is elastically deformed. As a result, the spark protection device 54 is assembled, and by this assembly, the electric connection portion 34a of the terminal fitting 34 is pressed against the other end surface of the heat-sensitive melting member 53 and elastically pressed and held. The structure other than the above points is the same as that of the first embodiment.

Also in this second embodiment, the spark protection device 54 provided as a part of the current path flowing through the armature has the terminal fittings 34 and 47 which are thermally insulated from the brush 44 and the brush holder 43. Electrical connection parts 34a, 4
7a is electrically connected by the heat-sensitive melting member 53 and is equivalent to a switch using both terminal fittings 34 and 47 as switch contact pieces. Therefore, the same operation as in the first embodiment is obtained, and The intended purpose of the invention can be achieved. In addition, this second
In the embodiment, when an abnormal spark occurs, the heat-melting and melting body 53 mainly melts from the electric connecting portion 47a side.

Further, according to the second embodiment, the springiness of the tip end side portion 34b can prevent the electrical connection portion 34a and the heat-sensitive melting member 53 from making point contact and being electrically connected. Therefore, it is possible to prevent the electric current from concentrating and flowing in a local portion between the electrical connection portion 34a and the heat-sensitive melting member 53 with the turning on and off of the power supply, and thus the heat-sensitive melting member 53 is carelessly melted by the current concentration. You can eliminate fear.

FIG. 7 shows a third embodiment of the present invention.
The third embodiment is different from the first embodiment only in the structure around the electric connecting portions of both terminal fittings. Other configurations are the same as or similar to those of the spark protection device for a rotating electric machine brush according to the first embodiment shown in FIGS. 1 to 5, including a portion not shown in FIG. 7. 1 to 5 are substituted, and the same or similar components shown in the drawings are denoted by the same reference numerals as those in the first embodiment, and a description of those components and an explanation of the action and effect based thereon will be omitted. However, these same or similar parts also form part of the apparatus of this embodiment.

In the third embodiment, the electric connecting portion 47a of the terminal fitting 47 is not a bent portion at a right angle,
It is formed by a flat tip portion that extends parallel to the axial direction of the brush holder 43 and is closest to the commutator 29.

The electric connecting portion 34a of the terminal fitting 34 is also not a bent portion at a right angle, but is formed of a flat tip portion extending parallel to the axial direction of the brush holder 43 and closest to the commutator 29. The terminal fitting 34 is made of spring steel, and in particular, has a distal end portion 34b having an electrical connection portion 34a.
In the free state, as shown by the two-dot chain line in FIG. 7, is further away from the electrical connecting portion 47a of the terminal fitting 47.

One end surface of a heat-meltable cutting body 53 which has been formed in advance is melt-bonded to the electrical connecting portion 34a by pressure welding such as ultrasonic welding. The heat-sensitive melting body 53 has a caulking convex portion 53a on the other end surface, and the convex portion 53a is connected to the electrical connecting portion 4
It is caulked by passing through a hole provided in 7a. As a result, the tip side portion 34b is elastically deformed to assemble the spark protection device 53 as shown by the solid line in FIG. The caulking is carried out in the frame 21 through a tool through a machining hole (not shown) provided in the frame 21. The structure other than the above points is the same as that of the first embodiment.

Also in the third embodiment, the spark protection device 54 provided as a part of the current path flowing through the armature has the terminal fittings 34 and 47 which are thermally insulated from the brush 44 and the brush holder 43. Electrical connection parts 34a, 4
7a is electrically connected by the heat-sensitive melting member 53 and is equivalent to a switch using both terminal fittings 34 and 47 as switch contact pieces. Therefore, the same operation as in the first embodiment is obtained, and The intended purpose of the invention can be achieved. In addition, this third
In the embodiment, when an abnormal spark occurs, the heat-melting and melting body 53 mainly melts from the electric connecting portion 47a side.

Moreover, according to the third embodiment, when the heat-sensitive melting member 53 is melted, the electrical connection portion 34 of the terminal fitting 34 is formed.
Due to the springiness of the tip side portion 34b having a, the tip side portion 34b is immediately moved from the solid line position in FIG. 7 to the position shown by the chain double-dashed line.
The electrical connection between 4 and 47 can be immediately cut off to make the operation of the spark protection device 54 more reliable.

The present invention is not limited to the above embodiments. For example, in each of the above-described embodiments, the terminal fitting included in the brush device 41 is used for one of the pair of terminal fittings provided as a part of the current path flowing through the armature, so that the number of parts is small. Although there is an advantage that it can be completed, a pair of terminal fittings for the spark protection device can be provided separately from the terminal fitting 47 of the brush device 41. In this case, the position of the brush device 41 is not restricted. The spark protection device can be arranged around the commutator 29, and the degree of freedom in design can be increased.

Further, in the spark protection device of the present invention, the heat-sensitive fusing body does not melt at a predetermined temperature or less and electrically connects between the electric connecting portions to pass a current flowing through the armature, if necessary. It suffices as long as it melts at a predetermined temperature or higher and breaks the electrical connection due to the thermal effect of the abnormal spark, so that a thermal fuse can be used instead of the solder block used in each of the above-described embodiments.

Further, the present invention can be applied as a spark protection device for protecting a brush of a commutator motor which is driven by an alternating current and can be rotated in the forward and reverse directions, and a commutator which is driven by a direct current and can be rotated in the forward and reverse directions. It can also be applied as a spark protection device that protects the brush of an electric motor.

[0070]

As described in detail above, the spark protection device for a brush for a rotary electric machine according to the present invention constitutes a part of a current path flowing through the armature, and electrically connects the first and second terminal fittings. Since the parts are electrically connected with a heat sensitive fuse, the state equivalent to closing the switch is maintained below a predetermined temperature, and the abnormal temperature spark causes the heat sensitive fuse to rise above a predetermined temperature to melt the switch. Since the operation of the rotating electric machine is stopped by cutting the current path as an open state, even if an abnormal spark occurs between the commutator and the brush, the temperature of the brush does not rise abnormally, and the brush and The rotating electric machine can be protected. Moreover, for such protection, the temperature sensor and the signal processing circuit that is used along with it and has a large number of parts are not required, so the number of parts is small and the structure is simple. it can. Further, as described above, the number of parts can be reduced and the temperature of the brush does not affect the reliability of the protective operation against abnormal sparks.

[Brief description of drawings]

FIG. 1 is a side view showing a partial cross section of a structure of an electric vacuum cleaner including a spark protection device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a partial cross section of a configuration of a commutator motor of an electric blower included in the electric vacuum cleaner shown in FIG.

FIG. 3 is a cross-sectional view around the spark protection device, which is taken along line ZZ in FIG.

FIG. 4 is a front view showing the brush device shown in FIG. 3 as viewed from the commutator side.

5 is a diagram showing a configuration of an electric circuit of the commutator motor shown in FIG.

FIG. 6 is a cross-sectional view corresponding to FIG. 3 showing a configuration around a spark protection device according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view corresponding to FIG. 3 showing a structure around a spark protection device according to a third embodiment of the present invention.

[Explanation of symbols]

13 ... commutator motor, 25 ... Armature, 29 ... commutator, 31 ... Stator, 34 ... Terminal metal fittings 34a ... Electrical connection part of the terminal fitting 34, 41 ... Brush device, 42 ... Holder insulation, 42c ... partition wall, 43 ... Brush holder, 44 ... brush, 45 ... pigtail, 46 ... spring, 47a ... Electrical connection part of the terminal fitting 47, 53 ... Thermally sensitive material, 54 ... Spark protection device.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02K 13/00 H01R 39/46

Claims (2)

(57) [Claims] 1. A spark protection device for a brush for a rotating electric machine against a spark generated between a brush elastically pressed against a commutator of an armature and the commutator, wherein a current path flowing through the armature is provided. A first terminal fitting that is electrically connected and that has an electrical connection portion that is disposed near the commutator on the spark generation side, and that is electrically connected to a current path that flows through the armature. A second terminal fitting that is provided and has a non-contact electric connection portion that is disposed near the commutator and close to the electric connection portion on the spark generation side, and guides the axial movement of the brush. From brush holder
Front of the tip of the brush protruding to the commutator side
Exposed to abnormal sparks facing the side of the spark occurrence side
It is provided between the both electrical connection portions so as to electrically connect these both electrical connection portions at a predetermined temperature or less,
A spark protector for a brush for a rotating electric machine, comprising: a heat- sensitive fusing body that melts and cuts this electrical connection at a temperature equal to or higher than a predetermined temperature due to the thermal effect of the abnormal spark . 2. An elastically pressed commutator of an armature.
Against the spark generated between the brush and the commutator
A spark protective device for a rotating electric machine brush, which is electrically connected to a current path flowing through the armature.
And the spark generation side near the commutator
And a first terminal fitting having an electrical connection portion disposed in the armature and a current path flowing through the armature.
And the spark generation side near the commutator
In a contactless arrangement close to said electrical connection
A second terminal fitting having an electric connecting portion and a portion provided between the electric connecting portion and the electric connecting portion.
Make an electrical connection below a certain temperature and
If the temperature exceeds a certain temperature due to the thermal effect of the abnormal spark,
It consists of a heat-sensitive melting body that melts and cuts, and is located far from the brush in the first and second terminal fittings.
The one electrical connection that is placed well from the other electrical connection
It has a spring property in the direction of leaving, and due to this spring property,
Separation of the one electrical connection from the outer peripheral surface of the commutator
The distance between the heat-sensitive melting body and the
The size of the heat-fused body should be larger when it melts.
A spark protection device for a brush for a rotating electric machine, characterized by: