JP3816773B2 - Brush device and rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating electrical machine such as an electric motor or a generator and a brush device provided in the rotating electrical machine.
[0002]
[Prior art]
A motor equipped with a brush device such as a commutator motor is often used as an electric motor of an electric blower included in an electric vacuum cleaner.
[0003]
The brush device is generally configured as follows. A metal cylindrical brush holder is attached to an insulating holder made of an electrically insulating material fixed to the frame of the electric motor, and a rod-like carbon brush having a substantially rectangular cross section is accommodated in the holder so as to be movable in the axial direction. Houses a coil spring that biases the carbon brush. A brush cap that supports a coil spring is attached to the holder insulation, and the cap and the carbon brush are electrically connected by a pigtail.
[0004]
The carbon brush of this brush device is pressed against the commutator of the armature provided in the electric motor with its tip portion protruding from the tip opening of the brush holder. And, when energized, a rectifying action is performed between the commutator and the carbon brush. At that time, the carbon brush is reciprocally moved (axial vibration) by the commutator and the coil spring, although it is slight in the axial direction.
[0005]
By the way, the front end of the commutator side of the metal brush holder of the conventional brush device is an uncut cut end surface. The cut end face is not specially processed. A slight clearance is provided between the brush holder and the carbon brush in order to prevent the brush from being broken by the force received as the commutator rotates.
[0006]
For this reason, when the armature is rotated by energization, the tip of the commutator side of the carbon brush is dragged by the rotation of the commutator, and the carbon brush is held slightly inclined with respect to the brush holder within the clearance range. Is done. Along with this, the side surface of the tip of the commutator side of the carbon brush located on the downstream side in the rotation direction of the rotor competes with the cut end surface of the brush holder located on the downstream side in the rotation direction of the rotor. I can't interfere.
[0007]
Since the carbon brush vibrates in the axial direction as described above under such conditions, the side surface of the carbon brush is scraped by the cut end surface of the brush holder at the competing portion. In particular, as the rotational speed of the armature is increased to, for example, 4000 rpm or more by increasing the input to the motor, the number of occurrences of sparks due to rectification increases, and the number of occurrences of sparks increases. This is noticeable because the temperature of the brush rises and its thermal expansion increases.
[0008]
Part of the brush powder shaved in this way is in a slight gap between the side surface of the carbon brush located on the downstream side in the rotational direction of the rotor and the side wall of the brush holder located on the downstream side in the rotational direction of the rotor. It gets stuck and grows gradually. The solidified part of the brush powder substantially narrows the internal space of the brush holder at that part.
[0009]
Therefore, the axial movement of the carbon brush in the brush holder is not smoothly performed, and accordingly the spark is not stabilized and increases, so that the life of the carbon brush is easily lost. Such a situation is one of the obstacles in increasing the input power of the electric motor while ensuring durability.
[0010]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to obtain a brush device and a rotating electrical machine that can ensure smoothness of axial movement of a carbon brush and stabilize a spark.
[0011]
[Means for Solving the Problems]
The invention according to claim 1 is a coil spring in which a rod-like carbon brush in contact with a commutator is accommodated in a metal cylindrical brush holder so as to be movable in the axial direction, and the carbon brush is pressed against the commutator. Is assumed to be a brush device in which is housed.
[0012]
And in order to solve the said subject, the invention which concerns on Claim 1 curved the tip edge part of the said brush holder located in the rotation direction downstream of the said rotor away from the said carbon brush , The brush holder is protruded closer to the commutator side than the tip of the brush holder located on the upstream side in the rotation direction of the rotor .
[0013]
In the first aspect of the present invention, since the tip edge portion of the brush holder located on the downstream side in the rotation direction of the rotor is bent, the cut end surface of the brush holder is located on the downstream side in the rotation direction of the rotor. Run away from the side of the tip of the commutator side of the carbon brush. Therefore, the side surface of the carbon brush can be prevented from competing with the cut end surface of the carbon brush, in spite of the fact that the front end portion of the commutator side of the carbon brush is dragged by the rotation of the commutator in use.
[0015]
Moreover, Oite to a first aspect of the invention, since the leading edge of the brush holder side of the commutator-side tip of the carbon brush located downstream in the rotational direction of the rotor is in contact has shifted to the commutator side The inclination of the carbon brush in the use state with respect to the brush holder can be reduced. Accordingly, since the contact area of the carbon brush with the commutator is reduced, the frictional resistance with the commutator can be reduced.
[0016]
In order to solve the above problems, a rotating electric machine according to a second aspect of the present invention includes a stator, an armature provided through the stator and having a commutator attached thereto, and the armature rotated. 2. A frame which is freely supported and has the stator attached thereto, and the brush device according to claim 1, which is attached to the frame corresponding to the commutator.
[0017]
In this invention, in the state of use, on the commutator side of the carbon brush located on the downstream side in the rotational direction of the rotor on the cut end surface of the tip edge portion of the brush holder located on the downstream side in the rotational direction of the rotor Since the brush device according to claim 1 or 2 that prevents the side surface of the tip portion from competing is provided, a rotating electrical machine that can ensure smoothness of the axial movement of the carbon brush and stabilize the spark can be provided.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0019]
An electric blower 1 shown in FIG. 1 is mounted on a vacuum cleaner main body of an electric vacuum cleaner, and includes an electric motor unit 2 that constitutes an electric motor and a fan that performs an air blowing operation by receiving the rotational force of the electric motor unit 2. Part 3.
[0020]
The motor unit 2 forms a commutator motor, and includes a motor case 11 as a frame, a stator 12, an armature 13, and a pair of brush devices 14.
[0021]
As shown in FIG. 1, the sheet metal motor case 11 is formed by connecting a case main body 21 and a case end face plate 22. The opening edge of the cylindrical portion 21a of the case main body 21 forms an overhanging edge portion 21b. A short cylindrical bearing support portion 23 is formed at the center portion of the end plate 21c that forms the bottom of the cylindrical portion 21a of the case body 21, and a bearing 24 is accommodated in the support portion 23. A plurality of exhaust ports 25 are opened in the cylindrical portion 21a.
[0022]
The case end face plate 22 crosses the opening of the case main body 21 in the radial direction, and both ends thereof are screwed to the overhanging edge portion 21b. A short cylindrical bearing support portion 26 projecting out of the motor case 11 corresponding to the bearing support portion 23 is formed at the center portion in the longitudinal direction of the case end face plate 22. 27 is housed.
[0023]
The stator 12 includes a stator iron core and a stator winding wound around the iron core. The stator 12 is housed and fixed in the motor case 11 with the four corners of the stator core being pressed against the inner surface of the cylindrical portion 21a. An air passage 28 (only one is shown) is formed between the outer surface of the stator core and the inner surface of the cylindrical portion 21a facing the stator core. A terminal block 29 is attached to one end face of the stator core, and a terminal fitting 30 is attached to the stand 29. The terminal fitting 30 is electrically connected to the stator winding.
[0024]
The armature 13 is configured by attaching a commutator 31 to a rotating shaft 13a together with an armature core 13b to which an armature winding is attached. A terminal portion of the armature winding is connected to one end portion of a commutator piece equally distributed along the circumferential direction on the outer peripheral portion of the commutator 31. The armature 13 is also referred to as a rotor.
[0025]
As shown in FIG. 2 and FIG. 3A, the pair of brush devices 14 includes a holder insulation 41 made of an electrically insulating material, a metal brush holder 42 having a non-circular cylindrical shape, a carbon brush 43, and a terminal connection fitting. 44 and a coil spring 45 are formed.
[0026]
The holder insulation 41 has a cylindrical portion 41a for attaching the holder, a through hole 41b that is parallel to and adjacent to the cylindrical portion 41a, and an attachment convex portion 41c. The brush holder 42 is fixed to the holder insulation 41 by inserting almost half of the brush holder 42 into the cylindrical portion 41a. This fixing is achieved by sandwiching the wall of the cylindrical portion 41a located on the opposite side of the through hole 41b of the holder insulation 41 from both ends in the longitudinal direction of the wall with a pair of tongue pieces 42a and 42b bent from the brush holder 42. Has been done. The carbon brush 43 has a square cross section and is formed in a rod shape, and is accommodated in the brush holder 42 so as to be movable in the axial direction. One end of an energizing pigtail 46 is embedded and connected to the end of the brush 43 housed in the brush holder 42.
[0027]
As shown in FIG. 2, the terminal connection fitting 44 has a brush cap portion 44a and a mounting portion 44b bent at a substantially right angle thereto. The attachment portion 44 b includes a terminal connection portion 47 having a substantially U shape, a substantially hemispherical convex portion 48 located closer to the brush cap portion 44 a than the connection portion 47, and a tip side portion of the terminal connection portion 47. A cut and raised piece 49 is provided. A coil spring 45 is sandwiched between the brush cap portion 44 a and the carbon brush 43. A pigtail 46 is passed through the coil spring 45, and one end of the pigtail 46 is connected to the brush cap portion 44a.
[0028]
Therefore, the carbon brush 43, the terminal connection fitting 44, the coil spring 45, and the pigtail 46 form a unit. The terminal connection fitting 44 is attached to the holder insulation 41 by inserting the attachment portion 44b into the through hole 41b. In this attached state, the cut-and-raised piece 49 is hooked on the front end surface of the wall facing the through hole 41b of the cylinder portion 41a, and the convex portion 48 is elastically intimately contacted with the inner surface of the through hole 41b. Thereby, the terminal connection fitting 44 is prevented from coming off.
[0029]
The brush device 14 having the above-described configuration is a screw that is inserted into the brush body mounting hole 47 opened in the case body 21 from the outside of the case body 21 through the mounting protrusion 41c and screwed into the case body 21. By tightening 48, the case body 21 is attached. In this attached state, as shown in FIG. 1, the armature side tip of the brush holder 42 approaches the commutator 31, and the tip of the carbon brush 43 is projected from the tip by the spring force of the coil spring 45. And pressed against the circumferential surface of the commutator 31. In addition, the terminal connection portion 47 is brought into elastic contact with the distal end portion of the terminal fitting 30 inserted into the through hole 41b with the attachment, whereby the terminal fitting 30 and the terminal connection fitting 44 are electrically connected. It is connected to the.
[0030]
As shown in FIG. 3A, the brush holder 42 of the brush device 14 includes holder side walls 49 and 50 positioned upstream and downstream of the rotation direction (indicated by arrow A) of the armature 13 with the carbon brush 43 as a boundary. have. These holder side walls 49 and 50 are substantially parallel to each other. The tip edge 50a of the holder side wall 50 on the downstream side in the rotation direction protrudes closer to the commutator 31 side than the tip 49a of the holder side wall 49 on the upstream side in the rotation direction.
[0031]
As shown in FIG. 3B, the tip edge portion of the brush holder 42 located on the downstream side in the rotation direction, that is, the tip edge portion 50 a is bent so as to be away from the carbon brush 43. This bend is formed so as not to form an acute angle . Due to the bending of the tip edge portion 50a, the cut end surface 50b of the tip is not contacted with the side surface 43a of the carbon brush 43 facing the holder side wall 50. The side surface 43 a is located on the downstream side in the rotation direction of the armature 13.
[0032]
As shown in FIG. 1, the fan unit 3 includes a fan 51, a diffuser 52, and a fan cover 53. The fan 51 is connected by a nut 54 to a shaft end portion that penetrates the bearing 27 of the rotary shaft 13a. The diffuser 52 is supported by the overhanging edge portion 21 b and is disposed between the motor case 11 and the fan 51. The fan cover 53 covers the fan 51 and the diffuser 52 and is attached to the overhanging edge portion 21b. An air inlet 53 a is opened at the center of the fan cover 53. Therefore, the electric blower 1 is energized, and the fan 51 is rotated at a high speed of, for example, 4000 rpm or more together with the armature 13, whereby the air indicated by the arrows in FIG.
[0033]
When such an electric blower 1 is used, the commutator side tip of the carbon brush 43 pressed against the outer peripheral surface of the commutator 31 by the commutator 31 that rotates integrally with the armature 13 is shown in FIG. ) And dragged by the rotation of the commutator 31. Therefore, the carbon brush 43 is held in a slightly tilted state as shown in FIG. 3A within a slight clearance range between the carbon brush 43 and the brush holder 42.
[0034]
In this case, the tip edge portion 50a of the brush holder 42 located downstream in the rotation direction of the commutator 31 is bent away from the side surface 43a of the carbon brush 43 so as to escape, so that the tip edge portion 50a is cut off. The side face 43a of the carbon brush 43 hits the free cut end face 50b and does not compete.
[0035]
Therefore, the commutator side portion of the side surface 43a can be prevented from being scraped by the uncut cutting end surface 50b of the brush holder 42, even though the carbon brush 43 vibrates in the axial direction during use. Thereby, a part of the shaved brush powder is prevented from entering into a slight gap between the side surface 43a of the carbon brush 43 and the holder side wall 50a of the brush holder 42 and solidifying and growing.
[0036]
Accordingly, it is possible to ensure that the axial movement of the carbon brush 43 in the brush holder 42 is performed smoothly, so that the spark between the carbon brush 43 and the commutator 31 is stabilized, and accordingly the life of the carbon brush 43 is increased. Reduction can be suppressed.
[0037]
Furthermore, since the tip edge portion 50a of the holder side wall 50 protrudes closer to the commutator 31 side than the tip 49a of the holder side wall 49, the inclination of the carbon brush 43 with respect to the brush holder 42 when the electric blower 1 is used. Can be reduced. This inclination angle θ is shown in FIG. The smaller the tilt angle θ is, the smaller the contact area of the carbon brush 43 with the commutator 31 is. Therefore, since the frictional resistance between the carbon brush 43 and the commutator 31 can be reduced, the mechanical loss of the electric blower 1 can be reduced accordingly.
[0038]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0039]
According to the first aspect of the present invention, it is possible to prevent the side surface of the carbon brush from being scraped against the cut end surface of the brush holder in use, and to prevent the carbon brush from moving in the axial direction. The generation of the brush powder is prevented, so that the smoothness of the axial movement of the carbon brush can be ensured, and the brush device that can stabilize the spark can be provided.
[0040]
Furthermore, since the frictional resistance between the commutator of the carbon brush in the use state can be reduced according to the invention according to claim 1, it is possible to provide a brush device useful for reducing the mechanical loss of the rotating electrical machine.
[0041]
According to the invention of claim 2, because provided with a brush apparatus of claim 1, it is possible to provide a rotary electric machine capable of stabilizing the spark can ensure smooth of axial movement of the carbon brush.
[Brief description of the drawings]
FIG. 1 is a side view showing a partial cross section of an electric blower provided with an electric motor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a brush device included in the electric motor of FIG.
3A is a cross-sectional view of the brush device showing a relationship with the commutator along the line ZZ in FIG. 2; FIG.
FIG. 3B is an enlarged cross-sectional view illustrating a part of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electric blower 13 ... Armature (rotor)
13a ... Rotating shaft 14 ... Brush device 31 ... Commutator 41 ... Holder insulation 42 ... Brush holder 43 ... Carbon brush 43a ... Carbon brush side 45 ... Coil spring 46 ... Pigtail 49 ... Rotating direction upstream side wall 50 ... Rotating direction Downstream holder side wall 49a ... tip 50a of holder side wall 49 ... tip edge 50b of holder side wall 50 ... cut end face θ of tip edge 50a ... tilt angle of brush holder in use

Claims (2)

In a brush device in which a rod-shaped carbon brush in contact with the commutator is accommodated in a metal cylindrical brush holder so as to be movable in the axial direction, and a coil spring that presses the carbon brush against the commutator is accommodated.
The front edge of the brush holder located on the downstream side in the rotation direction of the rotor is curved away from the carbon brush, and the tip end of the brush holder located on the upstream side in the rotation direction of the rotor. A brush device characterized by protruding so as to approach the commutator side . A stator, an armature provided through the stator and having a commutator attached thereto, a frame rotatably supporting the armature and having the stator attached thereto, and the commutator mounted on the frame; Claims attached according to 1 A rotating electrical machine comprising the brush device according to claim 1.

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