JP2011115026A - Commutator motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a tip surface 26F of a brush 26 to be the so-called "entirely brought into contact" with a commutator 12 at an early stage, by preparing an oblique cut face 35 to narrow a width in the rotational direction of a tip contact surface 26F, and to prevent sparks, and the like from occurring on a downstream side in the rotating direction of the brush tip surface 26F, by cutting the oblique cut face 35 in such a direction that it gets away from the surface of the commutator 12, and securing a spatial distance between the cut face 35 and the commutator 12. <P>SOLUTION: The commutator 12 has a plurality of commutator segments 121, which successively contact the tip surface 26F of the brush 26 according to rotation of a rotor 13. The tip surface 26F of the brush 26 forms a concave curved plane along parts of a circumferential face formed by the commutator segments 121, in the rotating direction of the rotor 13. The edge on the downstream side in the rotating direction of the rotor 13 in the concave curved plane is chamfered to form the oblique cut face 35. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a commutator motor, and more particularly to a commutator motor used in an electric blower built in a vacuum cleaner.

The commutator motor includes a rotor having a commutator and a brush that is in circumferential contact with the commutator. One end of the stator winding is connected to the brush, and when the segments of the commutator in contact with the brush are sequentially switched, the energization current to the stator winding is switched to rotate the field magnetic flux.
In the commutator motor, the contact between the commutator and the brush must be good both electrically and mechanically, and proposals have been made for the brush to make good contact with the commutator.

  For example, in Patent Document 1, the width direction of the brush front end surface that is in contact with the commutator (the width direction refers to the direction along the rotation direction of the commutator; hereinafter the same), by cutting both ends of the brush. It has been proposed to prevent defects in the surface and roughening of the commutator.

Japanese Patent Laid-Open No. 10-23716

  The structure of the brush proposed in Patent Document 1 cuts both edges in the width direction of the tip surface (circumferential surface) of the brush, so that the brush contact area with the commutator is greatly reduced, and rectification failure due to an increase in current density is caused. There is a risk of occurrence. Moreover, in the proposal of patent document 1, since the both ends of the width direction of a brush are cut at right angles with respect to the brush side surface, the cut surface is a positional relationship close to the surface of the commutator, and the spatial distance is narrow. There is also a possibility that a spark current flows between the cut surface and the commutator to generate a spark.

As described above, the structure of the brush proposed in Patent Document 1 can prevent the brush from being broken or the commutator from being rough, but there is a risk of commutation failure and occurrence of sparks, and there is much room for improvement. Exists.
The present invention has been made for such a background, and it is a main object of the present invention to provide a commutator motor having a structure in which the commutator and the brush are in good contact with each other by improving the contact structure between the commutator and the brush. And

  Another object of the present invention is to provide a commutator motor that is easy to perform initial adjustment in which the contact state between the commutator and the brush is stabilized by the initial running-in of the manufactured commutator motor.

  The invention according to claim 1 is a commutator electric motor including a rotor having a commutator, a casing surrounding the rotor, and a brush attached to the casing and having a tip end surface surrounding the commutator. The commutator has a plurality of commutator segments that are arranged at equal intervals along the rotation direction of the rotor and sequentially contact the tip surface of the brush as the rotor rotates. In the rotation direction of the commutator segment is a concave curved surface along a part of the circumferential surface, the edge of the concave curved surface on the downstream side in the rotational direction of the rotor is chamfered, and the oblique cut surface The commutator motor is characterized in that

The invention according to claim 2 is the commutator motor according to claim 1, wherein the brush is plated on a surface other than the tip surface and the oblique cut surface that are in contact with the commutator. It is.
A third aspect of the present invention is the commutator motor according to the first or second aspect, wherein a plurality of grooves extending in the rotation direction of the rotor are formed on a tip surface of the concave curve. .

  According to a fourth aspect of the present invention, there are 20 or more commutator segments, and the width of the front end surface of the brush along the rotational direction of the rotor is such that the front end surface of the brush has a maximum of four commutator segments simultaneously. However, since the oblique cut surface is formed, the front end surface of the brush cannot simultaneously contact the four commutator segments, and the width contacts the three commutator segments. The commutator motor according to any one of claims 1 to 3, wherein the commutator motor is formed.

According to the first aspect of the present invention, since the oblique cut surface is provided to narrow the rotational width of the tip contact surface, the contact state between the brush and the commutator in the commutator motor is rectified at an early stage. The child can be brought into a so-called full contact state.
In addition, the diagonal cut surface is cut away from the commutator surface, and since a spatial distance is secured between the cut surface and the commutator, sparks and the like are generated downstream of the brush tip surface in the rotation direction. Can be prevented.

According to invention of Claim 2, since plating is given except for the front end surface and the diagonal cut surface of a brush, the electricity supply performance of a brush can be improved and the rectification | straightening performance can be aimed at.
According to the third aspect of the present invention, the front end surface is formed with a number of grooves in the rotation direction, and the front end surface has a continuous uneven shape when viewed in the direction orthogonal to the rotation direction. For this reason, the tip end surface is easily worn by sliding friction. Therefore, the brush front end surface can be brought into contact with the commutator in a shorter time.

  According to the invention of claim 4, the number of commutator segments with which the brush tip surface contacts at the same time is limited to 3 segments, and the rectification performance can be improved without significantly increasing the actual current density, A commutator motor with good performance can be made.

Drawing 1 is a perspective view which looked at electric blower 1 concerning one embodiment from the slanting back. FIG. 2 is a plan view of the electric blower 1. FIG. 3 is a perspective view illustrating components extracted from the commutator motor 11 incorporated in the electric blower 1. FIG. 4 is a perspective view of the commutator motor 11 shown in FIG. 3 with the rotor 13 and its related members and one (the front side in the figure) brush unit 6 omitted. 5A and 5B are three views for explaining the configuration of the brush 26, where FIG. 5A is a front view of the brush 26 (front view of the front end surface 26F of the brush 26), and FIG. 5B is a plan view of the brush 26. C) is a right side view of the brush 26. FIG. 6 is a partially enlarged view of the brush 26. FIG. 7 is a central longitudinal sectional view of the electric blower 1 shown in FIG. 2 cut along the central axis. FIG. 8 is a partially enlarged view of the flange 41. It is the figure which looked at the casing 2 whole from the back side. FIG. 6 is an enlarged view showing a state in which caulking 47 is applied to a portion of the rear end edge of the fan case 5 facing the reinforcing bead 45. FIG. 11 is a diagram illustrating a winding state of the stator winding 31. FIG. 12 is a diagram illustrating a configuration of the insulating sheet 50.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Drawing 1 is a perspective view which looked at electric blower 1 concerning one embodiment from the slanting back.
The blower 1 incorporates a commutator motor according to an embodiment of the present invention.
In FIG. 1, 2 is a casing 2 that forms the outer shape of the electric blower 1, and this casing 2 also serves as a casing of the commutator motor. The casing 2 includes a bracket 3 that covers the outside of the electric motor and a fan case 5 that covers the outside of the blower blades 4.

A brush unit 6 is attached to the bracket 3. A part of the brush unit 6 protrudes outward from the bracket 3. An attachment hole for the brush unit 6 is formed in the bracket 3, and the brush unit 6 is attached by being fitted into the attachment hole from the outside of the bracket 3.
In FIG. 1, 7 is a rotating shaft, and 8 is a bearing that rotatably holds the rear end of the rotating shaft 7.

FIG. 2 is a plan view of the electric blower 1. On the rear peripheral surface (right side in the figure) of the bracket 3, the brush units 6 are respectively attached up and down.
In addition, the front side (left side in the figure) of the fan case 5 is provided with a three-dimensional air inlet housing 10 that forms the air inlet 9.
FIG. 3 is a perspective view illustrating components extracted from the commutator motor 11 incorporated in the electric blower 1. That is, FIG. 3 is a perspective view showing the main components of the commutator motor 11 in the electric blower 1 shown in FIG.

The commutator motor 11 is provided with a rotor 13 having a commutator 12. The commutator 12 includes a plurality (for example, 20 or more) of commutator segments 121 arranged around the rotating shaft 7 included in the rotor 13. The commutator segments 121 are arranged at equal intervals along the rotation direction of the rotor 13 (rotating shaft 7).
The commutator motor 11 is also provided with a stator 14. The stator 14 includes a stator core 15 made of a plurality of magnetic materials stacked in the axial direction of the rotating shaft 7, a core insulator 16 that covers the front surface side of the stator core 15, and a core insulator 17 that covers the rear surface side of the stator core 15. ing. Although omitted in FIG. 3, a stator winding (described later) wound around the stator core 15 via core insulators 16 and 17 is provided.

The brush unit 6 includes a brush holder 18, a brush sleeve 19 inserted and held in the brush holder 18, a long bar-shaped brush housed in the brush sleeve 19, and a continuity electrically connected to the brush. A plate 20 is included.
In the brush unit 6 illustrated on the front side of FIG. 3, the brush holder 18 and the brush accommodated in the brush sleeve 19 are not shown in order to show the configuration and arrangement of the brush sleeve 19 and the conductive plate 20. ing.

Terminal blocks 21 and 22 are formed integrally with the core insulator 17. A first tab terminal 23 is mounted on each of the two terminal blocks 21, and a second tab terminal 24 is mounted on the other two terminal blocks 22.
In FIG. 3, reference numeral 25 denotes a bearing that rotatably holds the front side of the rotary shaft 7.

FIG. 4 is a perspective view of the commutator motor 11 shown in FIG. 3 with the rotor 13 and its related members and one (the front side in the figure) brush unit 6 omitted. According to FIG. 4, the relationship among the brush holder 18, the brush sleeve 19 and the brush 26 included in the brush unit 6 can be understood.
One of the features of this embodiment is the structure of the tip surface 26F of the brush 26. As shown in the enlarged view of the front end surface 26F, the front end surface 26F is formed with a large number of grooves 36 extending in the rotation direction A1 of the rotor, and is formed with ridges (projections) 37 alternately with the grooves 36. That is, the edge on the downstream side in the rotational direction A1 of the rotor is chamfered to form an oblique cut surface 35. This configuration will be described in detail below.

In FIG. 4, the stator winding wound around the stator core 15 via the core insulators 16 and 17 is wound in the direction indicated by the white arrow 31. The stator winding is wound around the upper portion as indicated by the white arrow 31 and is also wound around the lower portion, not shown, at a symmetrical position around the rotor.
5A and 5B are three views for explaining the configuration of the brush 26, where FIG. 5A is a front view of the brush 26 (front view of the front end surface 26F of the brush 26), and FIG. 5B is a plan view of the brush 26. C) is a right side view of the brush 26.

The brush 26 is made of carbon (carbon), and the overall shape thereof is a long and thin, substantially rectangular parallelepiped rod shape, and the front end surface 26F is a friction surface that contacts the commutator.
The upper surface 26U, the lower surface 26D, the left side surface 26L, the right side surface 26R, and the rear surface 26B of the brush 26 except for the front end surface 26F are plated (for example, copper plating), thereby improving the energization performance of the brush 26 as a whole. It has been. Further, a conductive pigtail 27 protrudes from the rear end surface 26B of the brush 26.

  One of the features in the form of the brush 26 is that the end surface 26F has a concave curved surface along a part of the circumferential surface formed by the commutator segment 121 in the rotation direction of the commutator 12 (rotation direction of the rotor 13). (See FIG. 5B). That is, the front end face 26F has a shape that can be brought into close contact (friction) with the peripheral surface of the commutator 12 without a gap. In addition, a large number of grooves extending in the moving direction of the commutator 12 (rotation direction of the rotor 13) are formed in parallel on the distal end surface 26F of the concave curved surface (see FIGS. 5A and 5C).

Further, the position of the edge 26F downstream of the front end surface 26F in the moving direction of the commutator 12 (rotation direction of the rotor 13) is chamfered to form an oblique cut surface (hereinafter referred to as “C cut surface”) 35. .
FIG. 6 shows a partially enlarged view of FIG. 5B and a partially enlarged view of FIG. 5C as B and C, respectively.

  In FIG. 6B, the C-cut surface 35 is formed at the edge of the downstream side of the tip surface 26F (the direction of movement of the commutator 12, the direction of rotation of the rotor 13 and the direction of the arrow A1). As shown in the figure, the C-cut surface 35 is an oblique cut surface in which an edge portion is chamfered obliquely from the front end surface 26F toward the right side surface 26R. Therefore, the C-cut surface 35 is cut in a direction away from the surface of the commutator 12 and is a cut surface in which a spatial distance from the commutator 12 is ensured.

Therefore, even if the current is concentrated on the plated surface of the brush 26 (for example, the right side surface), the spatial distance between the C-cut surface 35 and the commutator 12 is secured. It is possible to suppress the occurrence of sparks.
As shown in FIG. 6C, the front end face 26F is formed with a large number of grooves 36 extending in the moving direction of the commutator 12 (rotational direction of the rotor 13). In other words, the front end surface 26 </ b> F of the brush 26 is a jagged surface in which small peaks and valleys continue in a direction orthogonal to the rotation direction of the commutator 12.

For this reason, at the initial stage of rotation of the brush 26, the small convex portion of the tip surface 26F contacts the commutator 12, and the tip surface 26F follows the circumferential shape of the commutator 12 while the convex portion is shaved by sliding wear. As a result, the tip surface 26F comes into contact with the commutator 12 in a shorter time.
That is, after the commutator motor is assembled, a break-in operation is performed for characteristic stabilization and quality inspection. During the break-in operation period or during the initial operation period thereafter, the tip surface 26F of the brush 26 is connected to the commutator. 12, the so-called one-sided contact state in which only a part of the front end face 26F contacts the commutator 12 is eliminated, and the entire contact state can be realized during early operation.

  In this case, considering the contact state between the brush 26 and the commutator segment 121, the width W of the brush 26 (see FIGS. 5A and 5B) moves (rotates) the commutator segment 121 (FIG. 3). It is preferable that the dimension is a maximum of contact with four segments. The brush 26 having a width W that contacts the four segments at the maximum is provided with a C-cut surface 35 at the downstream edge of the tip surface 26F. Thus, the four segments cannot be in contact with each other at the same time, and most of the dimensions are in contact with the three segments.

  With this configuration, at the beginning of the operation of the commutator motor (during break-in operation or during the initial operation period), the width of the tip surface 26F of the brush 26 (width in the rotation direction) is increased by forming the C-cut surface 35. Due to the narrowness, sliding wear easily proceeds, and the brush tip surface 26F comes into contact with the commutator 12 in a short time. Thereby, early input stabilization of the commutator motor can be realized.

  Further, in the commutator motor, the tip surface 26F of the brush 26 is gradually scraped by sliding wear several tens of hours after the start of operation, the C-cut surface 35 disappears, and the brush width becomes wide. Thereby, the current density which flows into the brush 26 reduces, and a rectification effect | action can be stabilized more. At this time, if the width of the brush 26 is set so as to be in contact with the maximum four commutator segments 121, the current density can be reduced and chattering hardly occurs.

  Further, when the surface of the brush 26 other than the tip surface 26F and the C-cut surface 35 is plated in order to improve the current-carrying performance, current is concentrated on the plated portion. Therefore, sparks are likely to occur when the surface of the commutator 12 and the front end surface 26 </ b> F of the brush 26 are separated on the rear end side of the commutation direction (rotation direction of the commutator 12). In particular, in this embodiment, since the cut surface 35 is given to this part, there is a possibility that a spark is likely to occur. However, in this embodiment, since the cut surface is a C-cut surface, the tip of the plating applied to the surface of the right side surface 26R of the brush 26 by the C-cut surface 35 is separated from the surface of the commutator 12 so as to have a spatial distance. Has been. Therefore, generation | occurrence | production of a spark can be suppressed.

Further, by forming the C-cut surface 35, current concentration on the downstream end edge in the rectification direction on the tip surface 26F of the brush 26 is prevented, and loss of the edge side in the rectification direction of the brush tip surface 26F is prevented. be able to.
Further, since a large number of grooves 36 extending in the rotation direction of the commutator 12 are provided in parallel on the front end surface 26F of the brush 26, the front end surface 26F is easily scraped by frictional wear during a break-in operation, and the commutator surface is quickly introduced. There is an advantage that it is possible to achieve a full contact with.

Next, other features of the electric blower 1 according to this embodiment will be described with reference to FIGS.
FIG. 7 is a central longitudinal sectional view of the electric blower 1 shown in FIG. 2 cut along the central axis.
The outer shape of the electric blower 1 is configured by a casing 2 that surrounds the commutator motor 11 and a fan case 5 that covers the blower spring 4. In the electric blower 1, the fitting structure between the casing 2 and the fan case 5 is improved.

  That is, the front end side (the left side in FIG. 7) of the casing 2 has a flange 41 that extends outward, and a folded ring 42 that is further bent in the front end direction is formed on the peripheral edge of the flange 41. . On the other hand, the fan case 5 has a short cylindrical outer cylinder 43 and is press-fitted so that the rear end 44 of the outer cylinder 43 covers the outside of the folded ring 42 of the casing 2. Thereby, the casing 2 and the fan case 5 are combined.

  8A is a partial cross-sectional view of the flange 41, and FIG. 8B is a partial rear view of the flange 41. The features of this embodiment are bent at the outer peripheral edge of the flange 41 of the casing 2 so as to protrude to the front side (fan case 5 side), as shown in partial enlarged views in FIGS. The folded ring 42 is a circular ring, and at least one portion of the circular folded ring 42 has a reinforcing bead 45 that is convex in the central direction (axial side). Is formed. The reinforcing bead 45 is preferably provided at a position corresponding to the longitudinal center of the exhaust hole 46 when the exhaust hole 46 is formed in the flange 41 (see FIG. 8B). ).

When the entire casing 2 is viewed from the back side, a reinforcing bead 45 is provided at least at one place with respect to the folded ring 42 on the outer peripheral edge of the flange 41 as shown in FIG.
In this way, after the reinforcing bead 45 is provided on the folding ring 42 and the fan case 5 is press-fitted into the folding ring 42, as shown in an enlarged sectional view in FIG. A caulking 47 is applied to a portion facing the bead 45. The result is the configuration shown in FIG. 7 as a whole.

With this configuration, the flange 41 of the casing 2 can be reinforced with the reinforcing bead 45, so that the deformation of the flange 41 can be prevented.
Further, the caulking 47 can also prevent the fan case 5 from rotating in the rotational direction while ensuring the strength of the casing 2 to prevent the fan case 5 from coming off in the axial direction.
Further, the reinforcing bead 45 is provided at a position corresponding to the exhaust hole 46, thereby fulfilling a function of inducing exhaust.

Next, still another feature of the electric blower 1 according to this embodiment will be described with reference to FIGS. 11 and 12.
FIG. 11 is a diagram showing a winding state of the stator winding 31 around the stator core 15 (see also FIG. 4) of the stator 14, and shows a state where the stator 14 shown in FIG. 4 is viewed from the right side.
In FIG. 11, a stator winding 31 is shown as a set of a large number of small circles. The stator winding 31 is core insulators 16 and 17 attached to the stator core 15 (on the front side in FIG. 11). (Only the core insulator 17 appears) is wound around the stator core 15. In this case, an insulating sheet 50 made of, for example, a polyester film is disposed in a slot 52 (side on which the stator winding 31 is wound) formed inside the core insulators 16 and 17. The stator winding 31 is wound around the slot 52.

  In this case, the insulating sheet 50 is formed in a thin film shape so as not to narrow the winding space of the stator winding 31 (the space of the slot 52). However, when winding the stator winding 31, as indicated by a broken line 51 in FIG. 11, the insulating sheet 50 is pulled and protrudes into the winding slot 52 of the stator winding 31, so that the area of the slot 52 ( There has been a problem of narrowing the winding space area of the winding.

Therefore, in this embodiment, the insulating sheet 50 is configured as shown in FIG. 12, and the central portion in the longitudinal direction of the insulating sheet 50 can be extended in the longitudinal direction of the sheet.
That is, the insulating sheet 50 used in this embodiment has a longitudinal strip shape in which the width L is slightly larger than the width (thickness) of the stator core 15 as shown in FIG. And in the longitudinal direction center part, it has the structure by which several cut | interruptions 53 were alternately formed from both sides.

For this reason, as shown to FIG. 12 (B) with respect to the insulating sheet 50, when tensile force is added to the both ends of a longitudinal direction, it is set as the structure which the part of the cut | interruption 53 formed in the longitudinal direction center part extends.
As a result, the insulating sheet 50 has a bent shape shown in FIGS. 12C and 12D and is mounted in the upper and lower slots 53 of the stator 14. In the attached state, when a tensile force is applied to the upper part or the lower part of the insulating sheet 50 by the winding operation of the stator winding 31 in the upper slot 52 or the lower slot 52, the central part in the longitudinal direction of the insulating sheet 50 is applied. The cut 53 portion extends. Accordingly, the upper or lower portion of the insulating sheet 50 disposed in the slot 52 does not float from the inner peripheral surface of the slot 52, and the area of the winding region of the slot 52 is not reduced.

As a result, it is possible to effectively utilize the slot area, reduce the conduction loss of the commutator motor, and realize a high-performance motor.
The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Electric blower 2 Casing 3 Bracket 5 Fan case 6 Brush unit 11 Commutator motor 12 Commutator 13 Rotor 14 Stator 26 Brush 26F Brush front end surface 35 C cut surface 36 Groove 41 Flange 42 Folding ring 43 Outer body 45 Beat 50 Insulating sheet 121 Commutator segment

Claims (4)

A rotor having a commutator;
A casing surrounding the rotor;
A commutator electric motor including a brush attached to the casing and having a tip surface circumferentially contacting the commutator;
The commutator has a plurality of commutator segments that are arranged at equal intervals along the rotation direction of the rotor and that sequentially contact the tip surface of the brush as the rotor rotates.
A tip surface of the brush is a concave curved surface along a part of a circumferential surface formed by the commutator segment in the rotational direction of the rotor, and the downstream side of the rotational direction of the rotor in the concave curved surface. A commutator motor characterized in that an edge is chamfered to form an oblique cut surface.   The commutator motor according to claim 1, wherein the brush is plated on a surface other than the tip surface and the oblique cut surface that are in circumferential contact with the commutator.   The commutator motor according to claim 1, wherein a plurality of grooves extending in a rotation direction of the rotor are formed on a tip surface of the concave curve. 20 or more commutator segments are provided,
The width of the brush tip surface along the rotation direction of the rotor has a width that allows the brush tip surface to be in contact with the four commutator segments at the same time, but by forming the oblique cut surface The front end surface of the brush cannot contact four commutator segments at the same time, and has a width that contacts three commutator segments. Commutator motor.

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