JP5196927B2 - Brush device and electric motor provided with the same - Google Patents

Description

  The present invention relates to a brush device capable of preventing damage to a brush in a state before being incorporated in a frame of the motor, and a motor such as a commutator motor provided with the brush device.

  2. Description of the Related Art Conventionally, a brush assembly (brush device) provided in a commutator motor has a carbon brush disposed in a cylindrical brush holder so as to be movable in the axial direction of the holder, and the tip of the brush projects from the brush holder. The tip of the carbon brush is pressed against the commutator provided in the electric part of the electric blower with the coil spring (see, for example, Patent Document 1).

In this brush assembly, a conductive spring backing plate is fixed to the end of the brush holder opposite to the commutator, and this spring backing plate supports the end of the coil spring opposite to the carbon brush. Yes. The spring receiving plate is connected to an extendable connecting copper wire (pigtail). The connecting copper wire is provided through the coil spring and is electrically connected to the carbon brush.
JP 2006-340474 A (paragraphs 0011-0020, FIGS. 1-2)

  The brush assembly of Patent Document 1 is attached to the frame of the electric blower so that the carbon brush in contact with the commutator is pushed into the brush holder against the coil spring, and the urging force of the coil spring applies to the commutator. It is arranged in a state where the contact of the carbon brush is maintained.

  However, the brush assembly of Patent Document 1 does not include any means for restraining the movement of the carbon brush along the axial direction of the brush holder. For this reason, when the brush assembly in a state before being attached to the frame, that is, when the brush device is in a single and unused state, a portion covering substantially the entire length of the carbon brush is pushed out of the brush holder by the biasing force of the coil spring.

  In this state, the carbon brush being pushed out may collide with another object, thereby causing a high probability that the carbon brush will be damaged, such as a part of the side surface of the carbon brush being cut off.

  When the brush assembly is attached to the frame of the electric blower and the electric blower is used with the carbon brush being scratched, the carbon brush is used when the damaged part reaches the commutator. The current density through the brush is higher than before. For this reason, there exists a problem that the state of the rectification spark which generate | occur | produces between a commutator and a carbon brush deteriorates.

An object of the present invention is to prevent a brush from being damaged before being attached to a frame of an electric motor , and to contribute to a reduction in the number of man-hours for assembling an electric motor , and to provide a rectifying spark provided with the brush apparatus. The object is to provide an electric motor that can be stabilized.

The brush device of the present invention is a brush device that is attached to a frame of an electric motor including a commutator from the outside of the frame toward the peripheral surface of the commutator, an insulating base having a holder mounting hole, A spring receiver attached to the insulating base so as to face the holder mounting hole, one end and the other end are opened, and an escape portion is formed between both ends and toward the other end, and the other end is mounted on the holder. A cylindrical brush holder that is inserted into a hole and has one end protruding from the insulating base and attached to the insulating base, and a brush that is accommodated in the brush holder so as to be movable in the axial direction. The brush has a side face facing the rear end face and the rear end face facing the spring receiver, and is formed by the brush formed with a recess opened on the side face, and is sandwiched between the rear end face and the spring receiver. A coil spring that urges the brush in a direction protruding from the open end of the brush holder and presses the brush against the circumferential surface of the commutator, and an axially penetrating coil spring is provided. A pigtail whose one end is embedded in the rear end of the brush and whose other end is connected to the spring receiver, and an engaging portion that protrudes toward the side of the brush and is engaged with and disengaged from the recess through the escape portion And a holding member having a tip portion which is continuous from the engaging portion in the biasing direction of the coil spring, and the tip portion is inclined so as to gradually move away from the side surface of the brush. Holding the brush so that it does not protrude from the brush holder by engaging the engaging portion with the recess, and allowing the brush to protrude from the brush holder when the engagement is released. Comprising a member, it is characterized in that the recess is formed within the buried depth of the rear end portion of the brush of the pigtail.

  In the brush device of the present invention, in a state where this device is a single product and not used, the brush is opposed to the escape portion of the brush holder by pushing the brush against the coil spring so as to be immersed in the brush holder. Further, by engaging the engaging portion of the holding member, the brush can be held so as not to protrude from the brush holder. Thereby, it is possible to prevent the brush from being damaged by hitting with another object by the brush holder and protecting the brush.

  In addition, since the electric motor according to the present invention includes the brush device, the brush device is prevented from being damaged before the brush device is attached to the frame of the electric motor. The rectifying spark can be stabilized.

According to the brush device of the present invention, it is possible to prevent the brush from being damaged before being attached to the frame of the electric motor, and to contribute to a reduction in the number of assembly steps of the electric motor .

  According to the electric motor of the present invention, by providing the brush device, there is an effect that the rectifying spark can be stabilized.

  A first embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 1 in FIG. 1 indicates an electric blower mounted on a vacuum cleaner body of a vacuum cleaner, for example. The electric blower 1 includes a motor unit 2 that forms an electric motor and a blower unit 3 that is driven by the motor unit 2.

  The motor unit 2 includes a frame 5, a stator 11, a rotor 15, a commutator 18, and a pair of brush devices 21.

  The metal frame 5 is formed by connecting a frame end plate 7 to the other end of a bottomed cylindrical frame body 6 whose one end is closed by a closing wall 6a across the opening of the other end. The frame main body 6 has an annular flange portion 6b that protrudes outward around the other end opening. Both end portions of a frame end plate 7 having a strip shape in plan view are connected to the annular flange portion 6b. A bearing 8 is attached to the central portion of the closing wall 6 a of the frame body 6, and a bearing 9 is also attached to the central portion of the frame end plate 7.

  The stator 11 has a frame-shaped stator iron core and a stator winding wound around the stator core. Furthermore, the stator 11 has a terminal holder 12 made of an insulating material facing the closing wall 6a, and has a plurality of terminal fittings 13 (only one is shown) attached to the terminal holder 12. ing. A stator winding is electrically connected to a portion embedded in the terminal holder 12 of the terminal fitting 13. Among the plurality of terminal fittings 13, the pair of terminal fittings 13 correspondingly arranged so as to be separated from each other by 180 degrees in the circumferential direction of the frame body 6 has a portion arranged outside the terminal holder 12, This part is bent so as to protrude toward the inner peripheral surface of the frame body 6.

  The rotor 15 is formed by attaching a rotor core 15b to a rotary shaft 15a and winding a rotor winding 15c around the rotor core 15b. The rotor 15 is disposed inside the stator 11 with its rotating shaft 15a rotatably supported by bearings 8 and 9. The rotating shaft 15a passes through the bearing 9.

  The commutator 18 is located between the rotor core 15b and the bearing 8 and is attached to the rotary shaft 15a. A terminal portion of the rotor winding 15c is connected to a commutator piece having the commutator 18 exposed on the outer peripheral surface thereof.

  As shown in FIGS. 2 and 3, the brush device 21 includes an insulating base 22, a spring receiver 24, a brush holder 26, a brush such as a carbon brush 31, a coil spring 35, a pigtail 38, and a holding member 41. ing.

  The insulating base 22 is made of an insulating material and has a holder mounting hole 23 and a mounting portion 22a. The attachment portion 22a protrudes in a direction perpendicular to the direction in which the holder mounting hole 23 extends. The spring receiver 24 is attached to the insulating base 22 so as to face the holder mounting hole 23. The spring receiver 24 is made of a metal plate. An external lead wire (not shown) for supplying power to the motor unit 2 is connected to the spring receiver 24.

  The insulating base 22 is inserted into the frame body 6 of the frame 5 except for the end portion to which the spring receiver 24 is attached and the attachment portion 22a. In this inserted state, the insulating base 22 is attached to the frame 5 by screwing the screws 25 into the frame body 6 through the attachment portions 22 a in contact with the outer surface of the frame body 6.

  The brush holder 26 is made of metal and is formed in a cylindrical shape in which a cross section in a direction orthogonal to the longitudinal direction forms a square ring shape as shown in FIG. The brush holder 26 has one end 26a and the other end 26b open. The brush holder 26 has an escape portion 27 on its side wall 26c. The escape portion 27 is formed on the side wall 26 c at a position close to the other end 26 b between both longitudinal ends of the brush holder 26. The escape portion 27 is formed of, for example, a hole, but may be formed by a groove that opens to the other end 26b.

  The brush holder 26 is attached to the insulating base 22 with the other end 26 b inserted into the holder mounting hole 23 and one end 26 a protruding from the insulating base 22. The insulating base 22 has a relief groove 22b. The escape groove 22 b faces the escape portion 27.

  The carbon brush 31 is accommodated in the brush holder 26 so as to be movable in the axial direction (longitudinal direction) of the brush holder 26. The cross section in the direction orthogonal to the longitudinal direction of the carbon brush 31 forms a substantially square shape as shown in FIG. 5, and the four corners are chamfered. The axial length of the carbon brush 31 in an unused state is shorter than the axial length of the brush holder 26.

  The tip surface 31 a of the carbon brush 31 is formed as an arc surface that fits the commutator 18 to the peripheral surface. The rear end surface 31 b of the carbon brush 31 is formed as a surface perpendicular to the longitudinal direction of the carbon brush 31. The rear end face 31 b faces the spring receiver 24.

  The carbon brush 31 is provided with a recess 32 that opens to the side surface of the carbon brush 31 facing the side wall 26c of the brush holder 26 in which the escape portion 27 is formed. For example, as shown in FIG. 5, the recess 32 includes a groove extending in a direction orthogonal to the longitudinal direction of the carbon brush 31. In addition, the recessed part 32 can also be formed with a hole instead of a groove | channel.

  The coil spring 35 is sandwiched between the rear end surface 31 b of the carbon brush 31 and the spring receiver 24 in the insulating base 22. By the coil spring 35, the carbon brush 31 is urged in a direction protruding from the open end 26a of the brush holder 26. By this urging, the tip surface 31 a of the carbon brush 31 is pressed against the peripheral surface of the commutator 18.

  The pigtail 38 passes through the coil spring 35 in the axial direction, and has one end embedded in the rear end of the carbon brush 31 and the other end connected to the spring receiver 24. Therefore, the spring receiver 24 and the carbon brush 31 are electrically connected via the pigtail 38. Here, the rear end portion of the carbon brush 31 refers to a range of a length L corresponding to the height H (see FIG. 5) of the rear end surface 31b of the carbon brush 31 in FIG. 3 with reference to the rear end surface 31b. . The rear end portion of the carbon brush 31 having this length L is a portion that remains even when the carbon brush 31 is worn and shortened to the maximum.

  The pigtail 38 is formed by twisting dozens of thin copper wires, and can be freely deformed to follow the shortening of the brush accompanying the wear of the carbon brush 31 due to contact with the commutator 18. The embedding depth S of the pigtail 38 in the rear end portion of the carbon brush 31 is shorter than the length L. The recess 32 is formed in the range of the embedding depth S.

  The holding member 41 is made of metal, and is formed by cutting and raising a part of the side wall 26c of the brush holder 26 in this embodiment. Since the holding member 41 is formed integrally with the brush holder 26 as described above, the holding member 41 as a separate component from the brush holder 26 is not required, so that the number of parts and assembly man-hours of the brush device 21 can be reduced. preferable.

  The holding member 41 is disposed in the escape groove 22b of the insulating base 22 and can be elastically deformed. The front end portion 41 a of the holding member 41 forms a slanting surface for calling that inclines so as to gradually move away from the side surface of the carbon brush 31. The holding member 41 has an engaging portion 41 b between the tip end portion 41 a and the base of the holding member 41 that is the starting point of elastic deformation of the holding member 41. The engaging portion 41 b is a portion that is engaged with and disengaged from the concave portion 32, and is formed by a V-shaped bent portion that protrudes toward the side surface of the carbon brush 31. When the holding member 41 is in a free state, the engaging portion 41 b passes through the escape portion 27 and enters the brush holder 26.

  The unused state before the brush device 21 having the above-described structure is screwed to the frame 5 is shown in FIG. 3, and the brush device 21 is used for storage and physical distribution in this single product state. The brush device 21 shown in FIG. 3 is held by the holding member 41 in a state where the entire carbon brush 31 is pushed into the brush holder 26.

  This state is obtained by pushing the carbon brush 31 against the coil spring 35 so as to be immersed in the brush holder 26 while pushing away the engaging portion 41b of the holding member 41 on the side surface of the rear end portion of the carbon brush 31. Can do.

That is, the engaging portion 41 b of the holding member 41 is engaged with the concave portion 32 of the carbon brush 31 facing the escape portion 27 of the brush holder 26 as the carbon brush 31 is pushed. Due to the engagement of the engaging portion 41 b with the concave portion 32, the entire carbon brush 31 is held so as not to protrude from the one end 26 a of the brush holder 26 regardless of the biasing force of the coil spring 35.

  Therefore, when the brush device 21 is stored or the like, the carbon brush 31 is prevented from being damaged by hitting with other objects, and the carbon brush 31 can be protected by being prevented by the metal brush holder 26. Further, since the appearance of the brush device 21 in an unused state such as during storage becomes compact, a storage space or the like can be reduced.

  The brush device 21 in a single product state shown in FIG. 3 has its insulating base 22 screwed to the frame body 6 as described above, and at a position corresponding to the terminal fitting 13 directed to the inner surface of the frame body 6. It is attached to the frame 5. 3 is inserted into the frame 5 on the basis of the side surface of the mounting portion 22a of the insulating base 22 that contacts the frame main body 6. Accordingly, the terminal fitting 13 of the stator 11 is inserted into the back side of the holding member 41 as shown in FIG. In this case, the terminal fitting 13 is guided by the slanted tip portion 41 a of the holding member 41, so that it is smoothly inserted into the back side of the holding member 41.

  As the insertion of the terminal fitting 13 into the back side of the holding member 41 becomes deeper, the holding member 41 is elastically deformed in the direction away from the carbon brush 31 with its root as a fulcrum as shown in FIG. It is elastically deformed in the opposite direction to the member 41. As a result, the engagement between the engagement portion 41 b of the holding member 41 and the recess 32 of the carbon brush 31 is released.

  Therefore, by releasing the engagement, the carbon brush 31 is pushed toward the commutator 18 along the brush holder 26 by the biasing force of the coil spring 31 and protrudes from the one end 26 a of the brush holder 26. Thereby, the front end surface 31 b of the carbon brush 31 is pressed against the commutator 18.

  Thus, the restraint of the carbon brush 31 by the holding member 41 can be released along with the inevitable operation of attaching the brush device 21 to the frame 5 of the motor unit 2. Therefore, there is no need for special labor for removing the engaging portion 41b of the holding member 41 from the concave portion 32 of the carbon brush 31, and the number of assembling steps of the motor portion 2 can be reduced.

  In addition, since the terminal fitting 13 of the stator 11 is used for the release, there is no need for a dedicated part for the release, and the number of parts and assembly man-hours of the motor unit 2 can be reduced.

  Furthermore, since the holding member 41 and the terminal fitting 13 are elastically deformed and contact each other, these contacts are stably maintained. For this reason, electrical continuity between the brush holder 26 electrically connected to the carbon brush 31 by contact with the terminal fitting 13 of the stator 11 can be ensured via the holding member 41.

  Further, as shown in FIG. 1, the air blowing unit 3 includes a centrifugal fan 51, a fan cover 52, and a current plate 53. The centrifugal fan 51 is connected to the rotating shaft 15a. The fan cover 52 has a suction port 52a at the center, and is fitted and attached to the outer periphery of the annular flange portion 6b so as to cover the centrifugal fan 51. The rectifying plate 53 is sandwiched between the peripheral portion of the fan cover 52 and the annular flange portion 6b. The rectifying plate 53 guides the air sucked by the centrifugal fan 51 into the motor unit 2 while reducing the static pressure.

  Energization of the stator winding of the stator 11 of the motor unit 2 is performed via the spring receiver 24, the pigtail 38, the carbon brush 31, the brush holder 26, the holding member 41, and the terminal fitting 13, and thereby fixed. The child 11 generates torque. Energization of the rotor winding 15 c of the rotor 15 of the motor unit 2 is performed via the spring receiver 24, the pigtail 38, the carbon brush 31, and the commutator 18. As a result, the rotor 15 is rotated to drive the centrifugal fan 51. Therefore, the electric blower 1 performs a blowing operation.

  As the motor unit 2 of the electric blower 1 is operated, the length of the carbon brush 31 is gradually shortened by friction with the commutator 18. By the way, as described above, the carbon brush 31 is protected by the brush holder 26 so as not to be damaged such as a notch when the brush device 21 is not used alone.

  For this reason, as in the case where there is a chip on the side of the carbon brush, as the carbon brush is shortened, the chipped portion reaches the commutator 18 and the current density flowing through the carbon brush becomes higher than before, so It is possible to prevent the inconvenience that the state of the rectifying spark generated between the child 18 and the carbon brush deteriorates.

  Further, as described above, the length of the carbon brush 31 is gradually shortened with the operation of the motor unit 2, but the operation of the motor unit 2 is performed when the length of the carbon brush 31 becomes the shortest. The maximum operation time is controlled by, for example, an electric motor control circuit so that the embedding depth S in the carbon brush 31 is not reached. For this reason, it is possible to prevent the pigtail 38 from being exposed to the front end surface of the shortened carbon brush 31 and being rubbed against the commutator 18 to damage the commutator 18.

  A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted. Items different from those in the first embodiment will be described below.

  In the second embodiment, the insulating base 22 has a metal mounting hole 28 parallel to the holder mounting hole 23. The metal fitting mounting hole 28 is continuous with the escape groove 22b. Furthermore, in the second embodiment, instead of providing the holding member 41 integrally with the brush holder 26, the holding member 41 is integrally bent from the metal spring receiver 24. The holding member 41 has a hemispherical portion 41 c that is press-fitted into the metal fitting attachment hole 28, and is thereby inserted into the metal fitting attachment hole 28 and attached to the insulating base 22. The site | part in which the front-end | tip part 41a and the engaging part 41b of the holding member 41 were provided is arrange | positioned at the escape groove 22b. As a result, energization of the stator winding in the second embodiment is performed through the spring receiver 24 and its holding member 41 and the terminal fitting 13 in contact therewith. The configuration other than the items described above is the same as that of the first embodiment.

  Therefore, the brush device 21 of the second embodiment and the electric blower (not shown in FIG. 6) having the electric motor provided with the brush device 21 can also solve the problems of the present invention for the reason already described in the first embodiment.

The side view which shows a partial cross section and shows the electric blower provided with the electric motor which concerns on 1st Embodiment of this invention. Sectional drawing which expands and shows the brush apparatus periphery of 1st Embodiment with which the electric blower of FIG. 1 is provided. Sectional drawing which shows the brush apparatus shown in FIG. 2 in the single item state before being attached to an electric motor flame | frame. The front view which shows the relationship between the brush holder of the brush apparatus of FIG. 3, and the carbon brush arrange | positioned inside this. Sectional drawing which shows the carbon brush with which the brush apparatus of FIG. 3 was provided. Sectional drawing which shows the brush apparatus which concerns on 2nd Embodiment of this invention in the single-item state before being attached to an electric motor flame | frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Motor part (electric motor), 5 ... Frame, 11 ... Stator, 13 ... Terminal metal fitting, 15 ... Rotor, 15a ... Rotary shaft, 18 ... Commutator, 21 ... Brush device, 22 ... Insulation base, 22b ... Escape Groove, 23 ... Holder mounting hole, 24 ... Spring holder, 26 ... Brush holder, 26a ... One end of the brush holder, 26b ... Other end of the brush holder, 26c ... Side wall of the brush holder, 27 ... Escape portion, 31 ... Carbon brush ( Brush), 31a ... tip end surface of carbon brush, 31b ... rear end surface of carbon brush, 32 ... concave portion , 35 ... coil spring, 38 ... pigtail, 41 ... holding member, 41a ... tip portion, 41b ... engagement portion

Claims (3)

In a brush device that is attached to a frame of an electric motor including a commutator by being inserted from the outside of the frame toward the peripheral surface of the commutator,
An insulating base having a holder mounting hole;
A spring receiver attached to the insulating base opposite to the holder mounting hole;
One end and the other end are opened and a clearance is formed between both ends and toward the other end, and the other end is inserted into the holder mounting hole and the one end is protruded from the insulating base. A cylindrical brush holder attached to the base;
The brush accommodated in the brush holder so as to be movable in the axial direction, the brush having a side surface facing the escape portion and a rear end surface facing the spring receiver, and a recess opening on the side surface. When,
A coil spring which is sandwiched between the rear end surface and the spring support and biases the brush in a direction protruding from the opened one end of the brush holder, and presses the brush against the peripheral surface of the commutator ;
A pigtail provided through the coil spring in the axial direction and having one end embedded in the rear end of the brush and the other end connected to the spring receiver;
An engaging portion that protrudes toward the side of the brush, engages and disengages from the recessed portion through the escape portion , and a tip portion that continues from the engaging portion in the biasing direction of the coil spring; A holding member having a slanted surface that is inclined so that a distal end portion is gradually separated from a side surface of the brush, and the engagement portion is engaged with the recess to hold the brush so as not to protrude from the brush holder. And the holding member that allows the brush to protrude from the brush holder when the engagement is released,
Equipped with,
The brush device according to claim 1 , wherein the recess is formed within a range of a depth of embedding the pigtail in a rear end portion of the brush. 2. The brush device according to claim 1, wherein the holding member is cut and raised on a side wall of the brush holder facing the side surface on which the escape portion is formed . Frame,
A stator having terminal fittings fixed to the frame and projecting toward the inner surface of the frame;
A rotor rotatably supported by the frame;
A commutator attached to the rotating shaft of the rotor;
The brush device according to claim 1, wherein the brush device is attached to the frame by being inserted from the outside of the frame toward the peripheral surface of the commutator, and the brush is attached to the frame when the brush device is attached to the frame. The back side of the front end of the holding member provided in the apparatus and the terminal fitting come into contact with each other, and the holding member is deformed in a direction away from the brush. The brush device being held in a released state;
An electric motor comprising:

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