JPH0590874U - Rotating electric machine brush device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to obtain a brush device for a rotary electric machine that can improve the sitting property of the brush with respect to the commutator and improve the life. [Structure] A cylindrical brush guide 27 arranged to face the peripheral surface of a rotating commutator 15, a brush 41 fitted and supported in the guide 27 so as to be movable in the axial direction thereof. brush
41 and 41 are sandwiched between the commutator 15 and the brush 41
In the brush device 18 of the rotating electric machine including the coil spring 46 that presses against the peripheral surface of the brush 15, the anti-commutator side end surface 41a of the brush 41 with which the coil spring 46 abuts is positioned on the rear side in the rotation direction of the commutator 15. The other side surface 41 of the brush 41 positioned on the front side in the rotation direction of the commutator 15 with respect to the length A of the one side surface 41b of the brush 41.
It is characterized in that it is formed by an inclined surface which shortens the length B of c.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brush device that is used in a rotating electric machine such as a commutator motor or a generator and that includes a brush that makes sliding contact with the rotating commutator.

[0002]

[Prior Art]

 5 and 6 show different examples of conventional brush devices used in commutator motors. In these figures, 71 is a cylindrical brush guide, 72 is a carbon brush, 73 is a pigtail, and 74 is a pigtail. Is a coil spring, and 75 is a commutator fixed to the rotor shaft 76. In these examples, the carbon brush 72 is constantly pressed against the peripheral surface of the commutator 75 by the spring force of the coil spring 74.

In the conventional example shown in FIG. 5, the anti-commutator side end surface 72 a of the carbon brush 72, which is in contact with the coil spring 74, is formed at a right angle to the axial direction of the carbon brush 72, and the spring force of the coil spring 74 is increased. Of the carbon brush 72 is configured to substantially coincide with the axial direction of the carbon brush 72. Further, in the conventional example shown in FIG. 6, the anti-commutator side end surface 72a of the carbon brush 72 in contact with the coil spring 74 is inclined with respect to the axial direction of the carbon brush 72, and the inclined anti-commutator side end surface 72a is inclined. The component of the spring force of the coil spring 74 that acts on the brush guide 71 acts in the direction of the guide side wall 71a on the front side in the rotation direction of the commutator 75 in the brush guide 71, and presses the carbon brush 72 against the guide side wall 71a. ..

[0004]

[Problems to be solved by the device]

 However, in the configuration of the conventional example shown in FIG. 5, since the coil spring 74 is provided so as to meander in the brush guide 71, the acting direction of the spring force and the axial direction of the carbon brush 72 do not exactly match. In addition to this acting force E, the frictional resistance between the peripheral surface of the commutator 75 and the end surface of the carbon brush 72 on the commutator side due to the rotation of the commutator 75 (the arrow in FIG. 5 indicates the rotation direction). (That is, the commutator 75 is composed of a commutator piece 75a provided at regular intervals and an insulator 75b sandwiched between adjacent commutator pieces 75a. The child piece 75a and the groove 75c facing the insulator 75b are alternately provided, and the frictional resistance changes due to this structure.) Based on the force F that tries to slide the carbon brush 72, Playing (Also referred to as chattering) easily.

Therefore, there is a problem that the seating property of the carbon brush 72 with respect to the commutator 75 is good. Based on such poor seating property, there is a problem between the carbon brush 72 and the rectifier 75. Sparks are easily generated and the life of the carbon brush 72 is likely to be shortened.

Further, in the conventional example shown in FIG. 6, the point of action G of the coil spring 74 acting on the end surface 72a of the carbon brush 72 on the side opposite to the commutator is deviated from the fulcrum H of the carbon brush 72. A clockwise rotating moment M1 in FIG. 6 having a straight line connecting the points G and H as the arm length acts on the carbon brush 72. However, as described above, with the rotation of the commutator 75 (the arrow in FIG. 6 indicates the direction of rotation), the carbon brush is changed based on the strength change of the frictional resistance between this peripheral surface and the end surface of the carbon brush 72 on the commutator side. Since the force F that tries to drag 72 acts in a direction facing the rotational moment M1, the state in which the carbon brush 72 is stabilized at the rotational moment M1 is destroyed due to the fluctuation.

Therefore, although the carbon brush 72 is pressed against the guide side wall 71a on the front side in the rotation direction of the commutator 75 in the brush guide 71, the carbon brush 72 floats and the carbon brush 72 moves against the commutator 75. Since the seating property is easily impaired, the spark generated between the carbon brush 72 and the commutator 75 is apt to reduce the life of the carbon brush 72.

An object of the present invention is to obtain a brush device for a rotary electric machine, which can improve the sitting property of the brush with respect to the commutator and improve the life.

[0009]

[Means for Solving the Problems]

 The present invention relates to a cylindrical brush guide that is arranged so as to face the circumferential surface of a rotating commutator, a brush that is fitted and supported in the brush guide so as to be movable in the axial direction, and this brush. Is applied to a brush device of a rotary electric machine, the coil spring being provided between the commutator and the coil spring to press the brush against the peripheral surface of the commutator. The end surface of the brush on the side opposite to the commutator, which is in contact with the brush, is located on the front side in the rotation direction of the rectifier with respect to the length of one side surface of the brush located on the rear side in the rotation direction of the commutator. It is formed by an inclined surface that shortens the length of the other side surface.

[0010]

[Action]

 In the above structure, the inclined surface of the brush forming the end surface on the side opposite to the commutator receives the spring force of the coil spring that abuts against this surface and presses the brush against the commutator. A rotational moment is applied to the brush according to the inclination direction of, and the carbon brush is pressed against the guide side wall of the brush guide on the rear side in the rotational direction of the commutator. The direction of the force that this rotational moment tries to move the commutator side end of the carbon brush is the force by which the rotated commutator tries to drag the commutator side end of the carbon brush due to the inclination direction of the inclined surface. Is the same as the direction. Therefore, the state of the carbon brush, which is stabilized by the rotation moment, is destroyed by the force with which the carbon brush is dragged by the commutator based on the change in the friction resistance between the peripheral surface of the commutator and the end surface of the carbon brush on the commutator side. Is prevented.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. In FIG. 2, reference numeral 1 is a metal electric motor case, which is composed of a case body 2 and a case end plate 3.

The case body 2 is formed by opening a side of the cylindrical portion 4 having a bottom 4a opposite to the bottom 4a, and integrally mounting a mounting portion 5 at a peripheral portion of the opening. The mounting portion 5 is formed of an annular flat surface portion 6, a tubular portion 7, and a projecting edge 8. The annular flat portion 6 is formed integrally with the opening edge of the case main body 2 so as to project outward toward the outer side of the main body 2, and the tubular portion 7 is bent from the outer periphery of the annular flat surface portion 6 toward the bottom 4a side. It is formed in parallel with 2, and the projecting edge 8 is formed by bending at a right angle from the tip of the tubular portion 7 toward the outside. An exhaust hole 9 is provided on the bottom plate 4a side of the cylindrical portion 4, and an exhaust hole (not shown) is also provided on the bottom plate 4a. A bearing mounting portion 11 accommodating the bearing 10 is formed in the center of the bottom plate 4a.

The case end plate 3 has, for example, a substantially band plate shape whose planar shape extends in the radial direction so as to traverse the one end opening of the case main body 2 in the radial direction, and a bearing in which the bearing 12 is housed in the central portion thereof. The mounting portion 13 is integrally formed. Both ends of the case end plate 3 are screwed to the annular flat surface portion 6. Therefore, the one end opening of the case body 2 is partially opened without being completely closed.

A stator 14 and a rotor 16 with a commutator 15 arranged inside the stator 14 are housed in the case body 2. The stator core included in the stator 14 has a substantially quadrangular outer diameter when viewed from the axial direction, and the four chamfered corners thereof are fixed to the case body 2 so as to be in close contact with the inner surface of the cylindrical portion 4. .. Due to this fixing, four air passages 19 are formed between the inner surface of the cylindrical portion 4 and the outer surface of the stator core. The rotor 16 is rotatably provided with the rotor shaft 17 supported by the bearings 10 and 12, and the rotor shaft 17 penetrates the bearing 12 and the bearing mounting portion 13.

The commutator 15 is located on the bearing 10 side and is fixed to the rotor shaft 17. As shown in FIG. 1, the rectifier 15 includes a synthetic resin boss portion 15a that rotates integrally with the rotor shaft 17, and a multiplicity of circumferentially spaced boss portions 15a. A plurality of commutator pieces 15b and an insulator 15c that insulates the commutator pieces 15b from each other are provided. The end of the rotor winding is electrically connected to the commutator piece 15b.

Brush devices 18 on the positive electrode side and the brush device 18 on the negative electrode side are attached to the cylindrical portion 4 of the case body 2 with a commutator 15 interposed therebetween. The details of these brush devices 18 will be described below with reference to FIGS. 4 will be described.

The brush holder 21 included in the brush device 18 is made of an electrically insulating material such as synthetic resin, and the main body 22 thereof has an insertion hole 23 and has a substantially rectangular tube shape. A support piece 24, which overlaps the outer surface of the case body 2, is integrally provided on the body portion 22 so as to project therefrom. As shown in FIG. 2, the brush boulder 21 is fixed to the case main body 2 by inserting the main body portion 22 into the mounting opening 4 b opening in the cylindrical portion 4 and fastening the support piece 24 to the cylindrical portion 4 with the screw 26. There is.

A brush guide 27 made of metal is fitted into the insertion hole 23 of the brush holder 21. As shown in FIGS. 1 and 4, the brush guide 27 includes a pair of upper and lower guide side walls 27a and 27b that are parallel to each other, and a curved portion that connects one end of the side walls 27a and 27b and that bulges outward in the middle portion. The guide side wall 27c has a tubular shape, and the guide side wall 27c is parallel to the side wall 27c and connects the other ends of the guide side walls 27a and 27b, and has a curved side wall that bulges outward in the middle. , Is projected from the main body portion 22 toward the commutator 15.

The brush guide 27 is provided in the radial direction of the commutator 15 with its tip opening facing the peripheral surface of the commutator 15, and its guide side wall 27 c is located on the front side in the rotational direction of the commutator 15. The guide side wall 27d is located rearward of the commutator 15 in the rotation direction. In addition, in FIG. 1, the arrow I indicates the rotation direction of the commutator 15.

At the end of the brush guide 27 on the side opposite to the commutator 15, a retaining piece 28 that is hooked to the opening edge of the insertion hole 23 is bent, and the base of the brush guide 27 protruding from the main body 22 is bent. A cut-and-raised piece 25 that is hooked on the end surface of the main body portion 22 is formed in the portion. The cut-and-raised pieces 25 fix the brush guide 27 to the brush holder 21 with the main body 22 sandwiched between the cut-and-raised pieces 25.

The main body portion 22 of the brush holder 21 has a terminal mounting hole 29. The mounting hole 29 is provided substantially parallel to the insertion hole 23, and a terminal fitting 30 for supplying current is mounted therein.

The terminal fitting 30 is made of sheet metal and integrally includes a cap piece 31 that covers the opening end of the insertion hole 23 and a retaining piece 32 that is inserted into the terminal mounting hole 29. The retaining piece 32 has a convex portion 33 curved in an arcuate cross section and an elastically deformable bent portion 34 continuous with the convex portion 33 and bent into a mountain shape. The tops of the convex portion 33 and the bent portion 34 are pressed against the inner surface of the terminal mounting hole 29.

The tip of the bent portion 34 is projected from the terminal mounting hole 29 to the inside of the main body case 2, and a locking piece 35 hooked to the end surface of the main body 22 is integrally cut and raised at the protruding portion 34 a. There is. The locking piece 35 sandwiches the main body portion 22 with the cap piece 31 to prevent the terminal fitting 30 from coming off from the terminal mounting hole 29. The projecting portion 34a is inserted into a connection terminal (not shown) of a terminal block 36 attached to the stator core of the stator 14, and is connected to the stator winding via this terminal.

Inside the brush guide 27, as shown in FIG. 4, a rod-shaped carbon-based brush 41 whose cross section in the direction perpendicular to the axis is generally quadrangular is fitted and supported so as to be movable in the axial direction. .. The brush 41 is a so-called resin-binding type which is formed by sintering carbon powder as a main component and compression-molding the powder with a binder of a synthetic resin. Depending on the case, an appropriate amount of the required metal powder may be mixed.

The commutator-side end surface of the brush 41 is formed as a concave surface adapted to the peripheral surface of the commutator 15, and is in sliding contact with the commutator piece 15b. Furthermore, as shown in FIG. 1, the end surface 41a of the brush 41 on the side opposite to the commutator is formed as an inclined surface. The end surface 41a on the side opposite to the commutator is formed as an inclined surface or a curved surface having a curvature substantially the same as the inclined surface. Due to the anti-commutator side end surface 41a composed of such a slanted surface, as shown in FIG. 1, one slanted end C of the slanted anti-commutator side end surface 41a is provided at one end, and the guide side wall 27d is formed. The other side surface of the brush 41 facing the guide side wall 27c with the other inclined end D of the slanted anti-commutator side end surface 41a at one end than the length A of the one side surface 41b of the brush 41 facing each other. The length B of 41c is formed short. The inclination angle θ formed by the line parallel to the axis-perpendicular direction of the brush 41 and the oblique anti-commutator side end surface 41a is 12 to 15 °.

One end of a pigtail 42 is connected to the end of the brush 41 on the side of the end face 41 a on the side opposite to the commutator. That is, as shown in FIG. 3, one end of the pigtail 42 is inserted into the hole 43 formed at the end portion on the side of the end face 41a on the side opposite to the commutator side, and fixed by the copper powder 44 packed around the hole 43. Has been done. In order to ensure this fixation, the powder 44 surrounding one end of the pigtail 42 is hardened by impregnating it with a liquid adhesive. The other end of the pigtail 42 is spot-welded to the cap piece 31 that closes the opening end of the insertion hole 23.

A compression coil spring 45 is interposed between the end surface 41 a of the brush 41 on the side opposite to the commutator and the cap piece 31. The coil spring 45 sandwiches the brush 41 with the commutator 15 and constantly urges the brush 41 toward the commutator 15, so that the end of the brush 41 on the commutator 15 side is brushed. It projects from the guide 27 and is slidably pressed against the outer peripheral surface of the commutator 15.

The motor case 1, the bearings 10 and 12, the stator 14, the rotor 16, and the brush device 18 described above form a commutator motor used in an electric blower of an electric vacuum cleaner.

As shown in FIG. 2, a centrifugal fan 52, which rotates integrally with the rotor shaft 17 via a nut 51, is attached to an end portion of the rotor shaft 17 that protrudes from the motor case 1. There is. The fan 52 has a suction port 53 in the central portion and a discharge port 54 in the peripheral portion. The centrifugal fan 52 is covered with a fan cover 55. The cover 55 is fitted and mounted on the mounting portion 5 of the main body case 2, and the fan cover 55 has an opening 56 for sucking air. The opening 56 enters the suction port 53.

Therefore, when the centrifugal fan 52 is rotated, air is sucked through the opening 56, and the sucked air is discharged from the discharge port 54 of the centrifugal fan 52. A rectifying plate 57 that guides the air discharged from the centrifugal fan 52 into the motor case 1 is provided between the centrifugal fan 52 and the mounting portion 5. The rectifying plate 57 rectifies the air discharged from the centrifugal fan 52 and at the same time rectifies the pressure of the air from dynamic pressure to static pressure, and is screwed to the frame end plate 3. The air rectified by the rectifying plate 57 flows into the motor case 1, flows through the air passage 19, and is then discharged from the exhaust port 9 to the outside of the motor case 1.

In the brush device 18 having the above-described configuration, the end surface 41a of the brush 41 on the side opposite to the commutator 15 has a length of one side surface 41b of the brush 41 located on the rear side in the rotation direction of the commutator 15 as shown in FIG. Since the other side surface 41c of the brush 41 located on the front side in the rotation direction of the commutator 15 is formed with an inclined surface such that the length B becomes shorter than the length A, the brush 41 when the commutator 15 rotates The sitting comfort can be improved.

That is, the point of action J of the spring force of the coil spring 45 acting on the end surface 41 a of the brush 41 on the side opposite to the commutator and the fulcrum K of the brush 72 are displaced in the direction perpendicular to the axis of the brush 41. A rotating moment M having a straight line connecting the points J and K as the arm length acts on the brush 41, and a clockwise force in FIG. 1 is applied to the brush 41. As a result, one side surface 41b of the brush 41 is pressed against the guide side wall 27c of the brush guide 27 on the rear side in the rotation direction of the commutator 15.

When the commutator 15 is rotated in such a state, the commutator-side end surface of the brush 41 is subjected to a frictional force with the peripheral surface of the commutator 15 by a force L in the direction of the arrow in FIG. It tries to be dragged in the rotation direction of. Since this force L and the rotational moment M are in the same direction as the force exerted on the commutator side end of the brush 41, the strength of the frictional resistance between the peripheral surface of the commutator 15 and the commutator side end of the brush 41 changes. Despite the fluctuation of the force L in accordance with the above, it is possible to prevent the brush 41 from losing its stable state by the rotation moment M.

Therefore, in the brush 41, as shown in FIG. 1, the slanted end C of the anti-commutator side end surface 41a abuts on the guide side wall 27d, and the middle portion of the other side surface 41c on the front side in the rotation direction is guided to the guide side wall 27d. It is kept in contact with the commutator-side tip N and the commutator-side end surface is kept in contact with the peripheral surface of the commutator 15, and is gradually consumed.

In this way, the floating motion of the brush 41 is suppressed, and the sitting property of the brush 41 on the commutator 15 can be improved. Therefore, since it is possible to suppress the generation of sparks between the brush 41 and the commutator 15, it is possible to prevent the wear of the end surface of the brush 41 on the commutator side from being promoted, and to reduce the temperature rise of the brush 41. It is possible to extend the life of the brush device 41 and thus the life of the brush device 18.

[0036]

[Effect of the device]

 As described above in detail, according to the present invention, the free movement of the brush due to the rotation of the commutator is suppressed and the sitting property of the brush on the commutator is improved, so that the life can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view taken along line ZZ in FIG. 3, showing the configuration of a brush device according to an embodiment of the present invention.

FIG. 2 is a side view showing the configuration of an electric blower including the brush device shown in FIG. 1 in a partial cross section.

FIG. 3 is a vertical cross-sectional side view showing a configuration of a brush device according to an embodiment of the present invention in a state where the brush is worn.

4 is a cross-sectional view of the brush device taken along line YY in FIG.

FIG. 5 is a cross-sectional view showing an example of a conventional brush device.

FIG. 6 is a cross-sectional view showing another example of a conventional brush device.

[Explanation of symbols]

15 ... commutator, 18 ... brush device, 21 ... brush boulder, 27 ... brush guide, 27c, 27d ... guide side wall, 41 ... brush, 41a ... anti-commutator side end surface of brush,
41b ... One side of the brush, 41c ... Another side of the brush, 4
5 ... Coil spring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Yoshizawa 43 Horiyamashita, Hadano City, Kanagawa Prefecture Tokyo Electric Co., Ltd. Hadano Factory

Claims (1)

[Scope of utility model registration request] 1. A cylindrical brush guide arranged to face a peripheral surface of a rotated commutator, a brush fitted and supported in the brush guide so as to be movable in an axial direction thereof, and the brush. And a coil spring that presses the brush against the peripheral surface of the commutator and is sandwiched between the commutator and the commutator, the non-commutator side of the brush with which the coil spring abuts. A slanted surface that makes an end surface shorter than the length of one side surface of the brush located on the rear side in the rotation direction of the commutator, and the length of the other side surface of the brush located on the front side in the rotation direction of the commutator. A brush device for a rotating electric machine, characterized in that