JP3012783B2 - Brush device for rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush device used for a rotating electric machine such as a DC commutator motor and an AC commutator motor, or a generator, and more particularly, to a brush device of the rotating electric machine which has an abnormal spark. The present invention relates to a rotating electrical machine brush device provided with a protection measure for preventing abnormal overheating.

[0002]

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

However, for example, even one armature coil is disconnected, the commutator is eccentric, and the brush does not properly contact the commutator piece, or the brush is chattered due to the missing or abnormal wear of the brush. If, for example, the current suddenly stops flowing during rotation, a spark is abnormally generated between the commutator and the brush. If the abnormal spark moves around the commutator, the brush may be burned.

In order to prevent the brush life from being abnormally shortened due to the heat of the abnormal spark, 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 motor when the temperature becomes high is disclosed in
No. 93147.

[0005] In addition, in order to prevent abrasion due to excessive temperature rise of the brush and to prevent burnout of the motor, etc., the temperature of the brush or brush holder is detected by using a temperature sensor, and the temperature of the motor is determined based on the detected temperature. Japanese Patent Application Laid-Open Nos. 6-14501 and 2
-26253, JP-B-61-48359,
And JP-A-51-129601.

Further, in order to prevent the brush from being worn during the cooling operation, or to prevent the brush from being worn due to an excessive temperature rise, a heat responsive element made of a shape memory alloy is used to operate the brush. A technique for bringing a brush and a commutator into a non-contact state when a situation occurs is disclosed in Japanese Patent Application Laid-Open No. 5-30070.
No. 5, JP-A-2-177282, and the like.

[0007]

These various techniques are effective as protection measures for the electric motor.

However, the above-described various techniques for protecting the electric motor 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 as a whole of the protection device is large and the cost is high. In addition, the operation reliability of the signal processing circuit decreases in accordance with the number of the circuit components, and in addition, there is a problem that it is difficult to provide a high-quality one because of the variation of the temperature sensor itself. Furthermore, since the temperature sensor has an insulating layer of glass or ceramics and has a considerable heat capacity, it is disadvantageous in protecting the motor by quickly following the rapid temperature rise of the brush due to the occurrence of abnormal spark. There is also a problem.

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

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inexpensive rotating electric machine that can protect a commutator motor with high reliability against abnormal temperature rise of a brush caused by abnormal spark generated between the commutator and the brush. To obtain a brush device.

[0011]

SUMMARY OF THE INVENTION The present invention provides a brush device for a rotating electric machine, in which a brush urged by a spring and elastically pressed against a commutator is provided in a cylindrical brush holder fixed to holder insulation. It is assumed.

In order to achieve the above object, the brush and the brush holder are formed of an electric conductor, and the brush holder and the brush are electrically connected.
A terminal fitting which is used as a switch contact piece together with the brush holder and is provided near the brush holder by being electrically connected to a current path flowing through an armature, between the brush holder, the brush holder and the terminal fitting. These are electrically connected at a predetermined temperature or lower, and a protection switch means including a heat-sensitive fusing body for fusing and cutting the connection at a predetermined temperature or higher is provided, and the terminal fitting and the heat-sensitive fusing body are connected to the brush. The terminal is arranged on the side where a spark generated between the commutator and the commutator is generated, and the end of the terminal fitting on the commutator side protrudes more toward the commutator than the end of the brush holder on the commutator side.

[0013]

In the construction of the present invention, the protection switch means using the brush holder and the terminal fitting as the switch contact pieces does not melt at a predetermined temperature or lower, so that a state equivalent to closing the switch can be said. Since it is held, the commutator is electrically connected to a current path flowing to the armature via the protection switch means and the brush which are electrically connected to each other. When the temperature reaches or exceeds a predetermined temperature, the protection switch means cuts off the electrical connection between the brush holder as a switch contact piece and the terminal fitting due to the melting of the heat-sensitive fusing body, so that the switch is opened. Thus, the current is cut off in the brush device, and the operation of the rotating electric machine including the brush device is stopped.

The protection switch means arranged on the side where the spark is generated can receive abnormal sparks more effectively as compared with the case where it is arranged at another position. The tip of the terminal fitting protruding closer to the commutator side than the side tip is effectively exposed to abnormal spark.

By the way, the temperature of the brush in the brush holder rises as it is heated by resistance heating due to energization, frictional heat caused by sliding contact with the commutator, and sparks. The temperature is also raised. Therefore, the temperature of the heat-sensitive fusing body is affected by the temperature of the brush via the brush holder. Therefore, when the heat-sensitive fusing body is blown mainly by the heat transmitted from the brush holder side, the temperature difference between the time of occurrence of the normal spark and the time of occurrence of the abnormal spark cannot be secured so large, and the brush is shaken in the brush holder. Since there is a large variation in the cage contact, it is difficult to realize the fusing of the heat-sensitive fusing body at a predetermined temperature with higher reliability.

However, according to the present invention, the commutator-side tip of the terminal fitting can be more effectively exposed to the spark than the commutator-side tip of the brush holder as described above. The heat-sensitive fusing body can be blown from the terminal fitting side by heat, and the influence of the heat of the brush on the fusing of the heat-sensitive fusing body can be reduced. As a result, due to the occurrence of abnormal spark, the temperature of the terminal fitting heated by this spark is quickly raised, and the temperature difference of the terminal fitting provided with the heat-sensitive fusing body is set to the time when the normal spark is generated and the abnormal spark is generated. It can be bigger with time.

[0017]

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

The cleaner body 1 is provided with a turnable front wheel 5 and a large-diameter rear wheel 6, and the cleaner body 1 can move through these rolling motions. The vacuum cleaner body 1
It is drawn through a dust suction hose (not shown) inserted and connected to a suction port (not shown) provided at the front end thereof.

In FIG. 1, reference numeral 7 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. The grid 7 supports a dust bag 9 connected to the suction port from behind via a filter 8. Also, 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 holes 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) rotated by the commutator motor 13, a fan cover that covers the centrifugal fan, and a rectifier 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 by the blower supporting walls 14 and 15 of the cleaner body 1 via a 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.
By being supported in a vibration-proof manner via 8, it is built in the cleaner body 1 with its axis horizontal. Note that the arrangement of the electric blower 11 is not limited to a horizontal position. For example, in the case of a pot-type electric vacuum cleaner, the electric blower 11 is built in the main body of the vacuum cleaner with the axis thereof being vertical. The first rubber packing 16 in the form of a ring is provided so as to fit around the periphery of the fan cover, and the second rubber packing 18 in the form of a cap is provided so as to fit over the rear end of the commutator motor 13. ing. The electric blower 11 sucks air in the dust collection chamber 3 and exhausts the air from the commutator motor 13 to the outside.

A cylindrical silencer 19 surrounding the commutator motor 13 is housed in the cleaner body 1. The silencer 19 is made of a breathable synthetic resin such as urethane foam and is flammable. The wind flowing out of the electric blower 11 flows through the rear part of the cleaner main body 1 through the silencer 19 and is discharged out of the cleaner main body 1 through the exhaust hole 10.

The configuration of the commutator motor 13 will be described with reference to FIG. In FIG. 2, reference numeral 21 denotes 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 are attached. The end plate 23 is in the form of a strip crossing the opening of the frame 21 in the radial direction, and has a suction opening 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 an end of the shaft 26 that passes through the bearing 24. The armature 25 includes a rotating shaft 26, an armature core 27 fitted and fixed to the shaft 26, an armature coil 28 wound around the core 27, and a fixed commutator 29 fitted to the rotating shaft 26. Armature coil 28
Are connected to a plurality of commutator pieces 29a arranged in parallel with each other on the periphery of the commutator 29 so as to be insulated from each other.

A plurality of (only one is shown in FIG. 2) outlets 38 are provided in the peripheral portion on the bottom side of the frame 21 and the like. Located between the outlet 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,
The four corners are press-fitted into the inner peripheral surface of the frame 21 and provided.
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.

At the end of the stator 31 located on the bottom side of the frame 21, a winding holder 33 made of synthetic resin for electrical insulation is mounted, and a pair of unillustrated integrally formed with the holder 33 is provided. The terminal block has a connection terminal 34 (2 in FIG. 3).
(See dotted line). The terminal of the stator coil 31 a is electrically connected to the connection terminal 34, and the connection terminal 34 has a flat terminal plate portion extending to approach the inner peripheral surface of the frame 21. .

A pair of brush devices 41 are mounted on 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, the brush device 41 includes a holder insulator 42, a brush holder 43, a brush 44, a pigtail 45, and a coil spring 46.
And protection switch means 47.

More specifically, the holder insulation 42 has a melting point, for example.
It is formed of a synthetic resin such as nylon with glass having an electrical insulation of 210 ° C. 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
b overlaps the outer peripheral 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 passing therethrough and screwing to the peripheral wall. As shown in FIGS. 3 and 4, the holder insulating body 42a is provided with a terminal mounting hole 49.

The brush holder 43 has a cylindrical shape with one end opened and the other end closed by a bottom wall 43e made of an electric conductor such as a brass or galvanized steel plate or a copper plate. As shown in FIG. 5, the cylindrical portion of the brush holder 43 has a pair of opposed flat wall portions 43a and 43b.
And a pair of opposite wall portions 43c and 43d connecting these two wall portions 43a and 43b, respectively, and are formed in a rectangular cylindrical shape.

The brush holder 43 has a holder insulation 42
Is inserted from the commutator 29 side, and is attached to the holder insulator 42 so as not to move in the axial direction. The bottom wall 43e side is arranged outside the frame 21. In FIG. 5, reference numeral 43f denotes a stopper cut and raised from the brush holder 43 and brought into contact with the tip of the holder insulating body 42a.

As the brush 44 made of an electric conductor, a carbon brush formed by binding carbon powder with a binder made of a synthetic resin binder and solidifying it into a prismatic shape is employed. Brush 44
Is provided movably in the axial direction in the brush holder 43 using the holder 43 as a guide. One end of a pigtail 45 is embedded in the brush 44, and these are electrically connected. The other end of the pigtail 45 is fixed to the bottom wall 43e by spot welding or the like.
Thus, the brush holder 43 and the brush 44 are electrically connected via the pick tail 45.

The spring 46 is housed in the brush holder 43 with its both ends in contact with the brush 44 and the bottom wall 43e, and the spring 44 projects from the open end of the brush holder 43 by the spring force of the spring 46. Has been energized. Therefore, in the free state of the brush device 41, the brush 4
When the brush device 41 is fixed to the frame 21, the brush 44 hits the outer circumferential surface of the commutator 29 and is pushed into the brush holder 43 when the brush device 41 is fixed to the frame 21. And is pressed and held against the outer peripheral surface.

The protection switch means 47 includes a part of the brush holder 43, a terminal fitting 50 disposed near the part of the brush holder 43, and a conductive heat-sensitive fusing body 51. The terminal fitting 50 is formed of a spring plate having elasticity, and has a connection portion 50a bent in a substantially rectangular shape. By inserting the connecting portion 50 a into the terminal mounting hole 49, the terminal fitting 50 is attached to the wall 43 of the brush holder 43.
It is arranged near the outside of a.

The connecting portion 50a elastically closely contacts the opposing inner surfaces of the terminal mounting holes 49 to maintain the mounting state of the terminal fitting 50. The flat terminal plate portion of the connection terminal 34 is inserted into the terminal mounting hole 49 along with the above-described mounting of the brush device 41, whereby the stator coil 31 a and the terminal fitting 50 are connected via the connection terminal 34. Are electrically connected.

As shown in FIG. 3, the protruding portion of the terminal fitting 50 protruding out of the terminal mounting hole 49 is provided with an insulating gap between the terminal fitting 50 and the wall 43a of the brush holder 43, and is substantially formed with the wall 43a. In addition to being arranged in parallel, the tip, that is, the commutator-side tip 50b is protruded closer to the commutator 29 side than the commutator-side tip 43a1 of the wall 43a. In addition, t in FIG. 5 indicates a protrusion dimension of the distal end portion 50b with respect to the distal end 43a1.

The wall 43a of the brush holder 43 is located on the front side in the rotational direction of the commutator 29 (indicated by the arrow A in FIG. 3), in other words, on the side where sparks are generated between the commutator 29 and the brush 44. The wall to be located. The end of the wall portion 43a on the commutator 29 side is used as a fusing body arrangement portion 52.

The mounting portion 52 and the tip 5 of the terminal fitting 50
The portion near 0b is electrically connected via a thermal cutoff 51. The heat-sensitive fusing body 51 is made of, for example, a low-melting-point metal such as solder (this embodiment) or a heat-fusible synthetic resin or rubber having conductivity. The melting point of the heat-sensitive fusing body 51 made of solder or the like is lower than the melting point (210 ° C.) of the holder insulation 42, for example, 180 ° C.
The heat-sensitive fusing body 51 is solidified below its melting point to electrically connect the brush holder 43 and the terminal fitting 50, and melts above the melting point to cut off the electrical connection between the brush holder 43 and the terminal fitting 50. It is provided for.

The heat-sensitive fusing body 51 is made by molding a predetermined amount of heat-sensitive fusing material into a predetermined shape, for example, a short cylindrical shape as shown by a two-dot chain line in FIG. Is melted and adhered to the fusing body disposition portion 52 by the pressure contact, and is electrically connected to the disposition portion 52 and fixed thermally.

A terminal fitting 50 is attached to the heat-sensitive fusing body 51.
Are brought into close contact with each other by the spring force of the metal fitting 50, whereby the heat-sensitive fusing body 51 and the terminal metal fitting 50 are electrically connected. Note that the terminal fitting 50 is in a free state when the heat-sensitive fusing body 51 is blown, or is restricted by a spring contact portion of the holder insulating main body 42a and the wall portion 43 is closed.
It is provided so as not to contact a.

FIG. 6 is a diagram showing an electric circuit of the commutator motor 13. One of the brush devices 41 pressed against the commutator 29 is connected to one of the stator coils 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 corresponding to the direction of the current passed through the stator coil 31a every half cycle of the alternating current.
And the current direction of the armature 25 are switched correspondingly, so that the rotation of the armature 25 is continued in one direction.

In the first embodiment, the stator coil 31a of the stator 31 of the commutator motor 13 and the brush 44 elastically pressed against the commutator 29 are combined with the protection switch means 47 and the pigtail 45. Are electrically connected via The protection switch means 47 has a configuration in which the terminal fitting 50 and the wall 43a which is a part of the brush holder 43 are used as a switch contact piece, and a spark generated between the brush 44 and the commutator 29 is formed. It is located on the originating side.

Therefore, below a predetermined temperature (the melting point of the heat-sensitive fusing body 51), the heat-sensitive fusing body 51 provided between the wall 43a and the terminal fitting 50 is maintained in a pre-formed state, and both switches are connected. The wall 43 of the brush holder 43 forming a piece
b and the terminal fitting 50 are electrically connected. In other words, when the temperature is lower than the predetermined temperature, the protection switch 47
Is maintained in 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 transferred from the commutator 29, whose brush 44 is in sliding contact with the armature coil, via the brush device 41 on the positive electrode side. Then, the 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 with the operation of the commutator motor 13, the blower operation by the electric blower 11 is performed. As a result, dust can be sucked into the cleaner body 1 of the vacuum cleaner, and the wind discharged from the centrifugal fan is
The frame 2 passes through a current plate and a suction opening (not shown).
1, the stator 31 in this frame 21
The air flows through the ventilation gap 32 while air-cooled, and further flows out of the commutator motor 13 through the outlet 30 after the brush device 41 is air-cooled. This wind sound is attenuated by passing through the silencer 19 surrounding the commutator motor 13. The wind exhausted as described above is exhausted through the exhaust hole 10 of the cleaner body 1. Therefore, it is possible to perform the cleaning by the vacuum cleaner under the above-described operation state.

In this operation, the short-circuit current flowing through the brush 44 between the commutator pieces 29a adjacent to the commutator 29 is cut off every time commutation is performed.
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 the brush 44, and the temperature of the brush 44 is transmitted to the brush holder 43. However, since the brush 44 swings, heat transfer to the brush holder 44 is performed. Is not performed stably. Further, the commutator-side tip 50b of the terminal fitting 50 closest to the commutator 29 is connected to the commutator-side tip 43a1 of the brush holder 43 with respect to the point of occurrence of the steady spark (the point where the short-circuit current is cut off). As a result, the temperature is not so much exposed to a steady spark, and the temperature rise is not so large.

By the way, for example, if even one of the armature coils 28 is disconnected for some reason, the commutator 29
Since the value of the current cut off with the rotation of the motor increases, the current ripple increases remarkably, the generated spark also abnormally occurs, and the thermal influence on the peripheral parts such as the brush 44 becomes large.

Due to such a situation, the commutator-side tip 50b of the terminal fitting 50 closest to the commutator 29 on the spark generating side, which is the place where the temperature of the brush device 41 rises faster, becomes abnormal spark. The temperature rises quickly due to the thermal effect of That is, since the abnormal spark extends along the outer peripheral surface of the commutator 29,
The commutator-side tip 50b is directly exposed to this, and the temperature of the terminal fitting 50 can be increased. Although the temperature of the brush holder 43 is also increased by the abnormal spark, since the commutator-side tip 43a1 is farther away from the commutator 29 than the commutator-side tip 50b, there is little thermal effect.

Therefore, the difference between the temperature of the terminal fitting 50 at the time of the normal spark and the temperature at the time of the abnormal spark can be increased. Thus, in spite of the fact that the heat-sensitive fusing body 51 is thermally affected by the temperature of the brush 44, if the temperature of the heat-sensitive fusing body 51 of the protection switch means 47 particularly becomes equal to or higher than a predetermined temperature, the heat-sensing body is accordingly Since the fusing body 51 is blown off from the terminal fitting 50 side, the electrical connection between the wall 43a of the brush holder 43 and the terminal fitting 50 is cut off, and the protection switch means 47 is in a state where the switch is opened, so to speak. .

In addition, since the heat-sensitive fusing body 51 of the protection switch means 47 employs a block preformed in a predetermined shape, the electrical connection between the wall 43a of the brush holder 43 and the terminal fitting 50 is established between them. Compared to the case where the solder is piled up, the amount of the heat-sensitive fusing body 51 can be easily and reliably managed, and the mass productivity can be improved.

As described above, in addition to the fact that the temperature difference of the terminal fitting 50 for melting the heat-sensitive fusing body 51 can be increased, the amount of the solder or the like forming the heat-sensitive fusing body 51 can be kept constant. Variations in the temperature at which the heat-sensitive fusing body 51 melts can be reduced, and accordingly, the protection switch means 47 can perform the protection operation with high reliability.

As described above, according to the commutator motor 13 including the brush device 41 having the above-described structure, when the brush 44 reaches a predetermined temperature or higher due to the occurrence of abnormal spark, the protection switch means 47 of the brush device 41 is provided. Current can be quickly cut off between the terminal fitting 50 and the heat-sensitive fusing body 51 to stop the further operation of the commutator motor 13, so that the abnormal spark between the commutator 29 and the brush 44 causes The temperature of the brush 44 does not rise abnormally.

Thus, there is no possibility that the synthetic resin component forming the binder of the brush 44 will burn and emit smoke or fire. Therefore, the flame of the brush 44 does not spread to the combustible silencer 19 through the outlet 38. In other words, the protection switch means 47 protects the commutator motor 13 and the main body 1 of the cleaner with the protection operation for quickly coping with an abnormal temperature rise of the brush 44, thereby eliminating the risk of burning.

As described above, the protection switch means 47
Since the above-described protection operation is obtained by the brush device 41 having
There is no need for a temperature sensor for obtaining a similar protection operation and a signal processing circuit with a large number of components accompanying the temperature sensor. Moreover,
One of the switch contact pieces of the protection switch means 47 also serves as the brush holder 43. Therefore, the number of parts is small, the structure is simple, the device can be operated with high reliability, and the brush device 41 can be provided at a low cost because a high-cost shape memory alloy is not used to obtain the same protection operation as described above.

In the configuration of the brush device 41, a pair of switch contact pieces provided in the protection switch means 47, that is, the brush holder 43 and the terminal fitting 50 are provided.
Are mounted on the same holder insulation 42.
Therefore, since the reference of the mounting position of the brush holder 43 and the terminal fitting 50 is the same, the brush holder 43
And the terminal fitting 50 can easily determine the mutual positional relationship. Therefore, it is possible to improve the reliability of the brush 44 for preventing the temperature from excessively rising. In addition, since there is no need to find another mounting structure for supporting the terminal fitting 50, the structure is simple and easy to manufacture.

Moreover, since the melting point of the holder insulation 42 is higher than the melting point of the heat-sensitive fusing body 51, the holder insulation 42 is heated.
The current path can be opened by fusing the heat-sensitive fusing body 51 before deformation occurs. Thereby, since the mutual positional relationship of the respective parts of the protection switch means 47 does not deviate from an appropriate state due to the deformation of the holder insulation 42 so as to be melted by the influence of heat, the protection operation of the protection switch means 47 is surely performed. Can be run.

FIGS. 7 to 9 show a second embodiment of the present invention. The second embodiment differs from the first embodiment only in the structure for mounting the heat-sensitive fusing body. Other configurations are shown in FIGS.
Since the configuration is the same as or similar to that of the rotary electric machine brush device of the first embodiment shown in FIGS. 1 to 6 including portions not shown in FIG. 9, the configuration not shown in FIG.
6 and the same or similar components shown in the drawings are denoted by the same reference numerals as in the first embodiment, and the description of those configurations and the description of the operation and effect based on them will be omitted. These same or similar parts also form part of the apparatus of this embodiment.

In the second embodiment, a fusing body mounting portion 52 is provided at the tip of the commutator side of the wall portion 43a of the brush holder 43 located on the spark generating side, over the entire width of the wall portion 43a.
Is provided. The disposition portion 52 is bent at right angles to the wall portion 43a by cutting and raising, so that the fusing body disposition portion 52 also serving as a commutator-side tip of the wall portion 43a is further away from the commutator 29. Have been. The protruding length of the fusing body arrangement portion 52 is determined so as not to contact the terminal fitting 50.

The commutator-side tip 50b of the terminal fitting 50 is
The metal fitting 50 is formed by a portion bent at a right angle in the direction of the brush holder 43 from a front end portion of the metal fitting 50, and the front end portion 50 is located closer to the commutator 20 side than the fusing body disposition portion 52, and One surface faces the commutator 29, and the other surface faces the fusing body arrangement portion 52. Further, the terminal fitting 50 of the present embodiment is a brush holder 43.
It has no spring property in the direction.

The heat-sensitive fusing body 51 is connected to the fusing body mounting portion 5.
2 or the commutator-side tip 50b of the terminal fitting 50 is melt-bonded by pressure welding such as resistance welding or ultrasonic welding, and is provided in a thermally conductive manner therebetween. In addition,
The configuration other than the above is the same as in the first embodiment.

In the second embodiment, the provision of the protection switch means 47 provides the same operation as in the first embodiment, thereby achieving the intended object of the present invention.

Moreover, according to the second embodiment, the reliability of the operation of the protection switch means 47 can be further improved.

That is, the fusing element disposition portion 52 is
, The arrangement 52 is less exposed to a steady or abnormal spark, and the heat transfer to the heat-sensitive fusing body 51 via the brush holder 43 at the time of occurrence of an abnormal spark is reduced. Thus, the heat transfer from the terminal fitting 50 to the heat-sensitive fusing body 51 can be increased. In addition, since the commutator-side tip portion 50b of the terminal fitting 50 is bent and is closely opposed to the commutator 29 with a larger area, the tip portion 50b is more reliably exposed to abnormal spark to effectively heat. The temperature of the terminal fitting 50 can be raised more quickly when an abnormal spark occurs.

Therefore, in the second embodiment, when an abnormal spark occurs, the heat-sensitive fusing body 51 can be more quickly blown off from the terminal fitting 50 side.
By cutting off the electrical connection between the wall 43a of the brush holder 43 and the terminal fitting 50, the reliability of the operation of the protection switch means 47 can be further improved.

FIGS. 10 to 13 show a third embodiment of the present invention. The third embodiment is different from the first embodiment in the configuration of the fusing body arrangement portion formed on the brush holder and the fixing structure of the heat-sensitive fusing body there. Other configurations are shown in FIGS. 1 to 6 including portions not shown in FIGS.
Since the configuration is the same as or similar to that of the rotary electric machine brush device of the first embodiment shown in FIG. 1, the components not shown are substituted with FIGS. 1 to 6 and the same or similar components shown in FIG. The same reference numerals as in the first embodiment denote the same parts, and a description of those components and a description of the operation and effect based on them will be omitted. However, these same or similar parts also form part of the apparatus of the present embodiment. It is.

In the third embodiment, the wall 43a of the brush holder 43 located on the front side in the rotation direction of the commutator 29, in other words, located on the side where the spark generated between the commutator 29 and the brush 44 is generated. The fusing body arranging portion 52 provided at the commutator-side end portion of the wall portion 43a is formed of a projecting portion that forms a step portion that projects outside the brush holder 43 over the entire width of the wall portion 43a. By providing the fusing body arrangement portion 52, a gap 53 as a heat resistance means is formed between the inner surface thereof and the tip of the brush holder 43.

As shown by the two-dot chain line in FIG. 13, the heat-sensitive fusing body 51 has a projection 51a integrally at the center of one surface thereof. The heat-sensitive fusing body 51 is fixed by bringing the one surface into close contact with the outer surface of the fusing body disposing portion 52 by passing the protruding portion 51a through a fixing hole provided in the fusing body disposing portion 52 and caulking the protruding portion 51a. Have been. The protrusion 51 a is accommodated in the gap 53 so as not to contact the brush 44 in the brush holder 43. Further, the one surface may be fixed to the outer surface of the fusing body disposition portion 52 by pressing the convex portion 51 a into the fixing hole.

A slit 55 is formed in the wall 43a of the brush holder 43 on the spark generation side over the entire width of the wall 43a. The slit 55 is formed on the wall 43a.
Is provided at a boundary position between the fusing body disposing portion 52 and other portions. This slit 55
Constitutes a thermal resistance increasing means for preventing heat transfer in the brush holder 43 from the commutator 29 side to the spring 46 side of the brush holder 43 by the thermal resistance of the portion. The configuration other than the above is the same as in the first embodiment.

In the third embodiment as well, the provision of the protection switch means 47 provides the same operation as in the first embodiment, thereby achieving the intended object of the present invention.

Further, the third embodiment is superior to the first embodiment in the following points because of the provision of the gap 53 and the slit 55.

That is, since the fusing body mounting portion 52 is formed so as to protrude outward and this mounting portion 52 is not in contact with the brush 44, the rotation of the commutator 29 (the direction thereof is 10 as indicated by the arrow A), the brush 44, based on the clearance between it and the brush holder 43,
Despite being slightly tilted with respect to the brush holder 43,
The brush 44 does not come into contact with the fusing body arrangement part 52, and a gap 53 is secured between the fusing body arrangement part 52 and the tip of the brush 44.

The gap 53 prevents heat at the tip end of the brush 44, which becomes high in temperature due to resistance heat generation and steady spark, from directly conducting heat to the fusing body arrangement section 52 due to its thermal resistance. For this reason, the temperature of the fusing body
4 can be lower. In this way, the fusing body arrangement part 5
Since the gap 53 increases the thermal resistance between the brush 2 and the tip of the brush 44, the temperature of the fusing body arrangement portion 52 can be kept lower than the temperature of the brush 44.

However, when an abnormal spark occurs, the temperature of the fusing body arrangement section 52 is increased by the influence of the abnormal spark as described above. Therefore, the difference between the temperature at the time of occurrence of a steady spark and the temperature at the time of occurrence of an abnormal spark of the fusing body disposition portion 52 and the heat-sensitive fusing member 51 disposed thereon can be increased.

Further, since the slit 55 is provided in the wall 43a, the heat resistance in the wall 43a is the largest in the slit 55. Therefore, when an abnormal spark occurs, the wall portion 4 whose temperature rises under the influence of this spark
In FIG. 3 a, the heat path which is to be conducted from the fusing body arrangement part 52 to the spring 46 side is cut off, so that the escape of the heat from the fusing body arrangement part 52 is reduced, and this arrangement part 52 and the heat-sensitive fusing body 51 Can be quickly raised. Thereby, the temperature difference of the fusing body arrangement part 52 at the time of the occurrence of the steady spark and the abnormal spark, and the temperature difference of the heat-sensitive fusing body 51 arranged at the installation part 52 can be increased.

Therefore, due to a slight variation in the melting characteristics of the heat-sensitive fusing body 51, a malfunction in which the protection switch means 47 performs the protection operation despite the occurrence of a steady spark is prevented, and an abnormal spark is generated. The protection operation can be performed only when
Can improve the reliability of the protection operation.

Further, since the thermal resistance increasing means for realizing the above operation is formed by the slit 55, the slit 55 can be easily formed only by performing a cutting process with a cutter such as a circular saw when providing the thermal resistance increasing means. And a slit,
In other words, since the thermal resistance due to the gap is large, the temperature of the fusing and disposing portion 52 can be quickly increased.

The present invention is not limited to the above embodiments. For example, the present invention can be applied to a commutator motor driven by AC and capable of rotating forward and reverse, and also to a commutator motor driven by DC and capable of rotating in one direction or rotating forward and reverse. Further, in implementing the present invention, the components of each of the above embodiments are arbitrarily and selectively combined, thereby forming a brush device having a function equivalent to or different from that of each of the above embodiments. It may be.

[0078]

Since the present invention is configured as described above in detail, it has the following effects.

According to the brush device for a rotating electric machine according to the first aspect, the protection switch means using the brush holder and the terminal fitting as switch contacts maintains a state equivalent to closing the switch at a predetermined temperature or less, and the predetermined temperature. In the above, since the heat-sensitive fusing body is melted by the heat transfer from the terminal fitting side and the switch is opened, and the operation of the rotating electric machine including the brush device is stopped, abnormal spark between the commutator and the brush is generated. Even if it occurs, the rotating electric machine can be protected so that the temperature of the brush is not abnormally raised. In addition, the temperature sensor and its associated signal processing circuit, which has a large number of parts, are not required for such protection, so the number of parts is small, the structure is simple, and the shape memory alloy is not used. And the number of parts can be reduced as described above. In addition, since the temperature difference between the terminal fittings at the time of occurrence of the normal spark and at the time of occurrence of the abnormal spark can be increased, the reliability of the protection operation against the abnormal spark can be improved.

[Brief description of the drawings]

FIG. 1 is a side view partially showing a configuration of a vacuum cleaner provided with a brush 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 the electric blower provided in the electric vacuum cleaner shown in FIG. 1;

FIG. 3 is a sectional view around the brush device shown along the line ZZ in FIG. 2;

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

FIG. 5 is an exploded perspective view showing a configuration of a protection switch means included in the brush device shown in FIG. 3;

FIG. 6 is a diagram showing a configuration of an electric circuit of the commutator motor shown in FIG. 2;

FIG. 7 is a sectional view corresponding to FIG. 3 showing a configuration of a brush device according to a second embodiment of the present invention.

FIG. 8 is a front view showing the brush device shown in FIG. 7 as viewed from the commutator side.

9 is an exploded perspective view showing a configuration of a protection switch means provided in the brush device shown in FIG. 8;

FIG. 10 is a cross-sectional view corresponding to FIG. 3 showing a configuration of a brush device according to a third embodiment of the present invention.

FIG. 11 is a side view showing the brush device according to the third embodiment as viewed from the commutator side.

FIG. 12 is a sectional view showing the configuration of the brush device shown in FIG. 11 in a free state.

FIG. 13 is an exploded perspective view showing a configuration of a protection switch means provided in the brush device shown in FIG. 11;

[Explanation of symbols]

 Reference numeral 13: commutator motor, 25: armature, 29: commutator, 31: stator, 41: brush device, 42: holder insulation, 43: brush holder, 43a: wall portion on the spark generation side of the brush holder, 43a1 ... Commutator-side tip of wall 43a, 44: brush, 45: pigtail, 46: spring, 47: protection switch means, 50: terminal fitting, 50b: commutator-side tip of terminal fitting 51: heat-sensitive fusing body, 52 ... Fusing body installation part.

Continuation of front page (56) References JP-A-56-112854 (JP, A) JP-A-1-198248 (JP, A) JP-A-8-237912 (JP, A) JP-A-8-168212 (JP) JP-A-9-74722 (JP, A) JP-A-9-37521 (JP, A) JP-A-9-19110 (JP, A) JP-A-9-9582 (JP, A) 8-322221 (JP, A) JP-A-8-298754 (JP, A) JP-A 61-65861 (JP, U) JP-A 3-39371 (JP, U) JP-A 59-111478 (JP, A) U) Japanese Utility Model Application Hei 1-90264 (JP, U) Japanese Utility Model Application Hei 2-136470 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 13/00 H01R 39/38

Claims (1)

(57) [Claims] 1. A brush device for a rotating electrical machine, wherein a brush urged by a spring and elastically pressed against a commutator is provided in a cylindrical brush holder fixed to holder insulation. The brush holder and the brush are electrically connected to each other, and the brush holder and the brush are electrically connected to a current path flowing through an armature by being used together with the brush holder as a switch contact piece and provided near the brush holder. Protection comprising a terminal fitting, the brush holder, and a heat-sensitive fusing body that electrically connects the brush holder and the terminal fitting between the brush holder and the terminal fitting at a predetermined temperature or lower and that cuts off the connection at a predetermined temperature or higher. A spark that includes switch means, and generates the terminal fitting and the heat-sensitive fusing body between the brush and the commutator. With placing the development side, the rotary electric machine brush device characterized by the commutator-side tip is projected on the commutator side than the commutator side tip of the brush holder of the terminal fitting.