JP3942854B2

JP3942854B2 - Brush holder mounting structure

Info

Publication number: JP3942854B2
Application number: JP2001269659A
Authority: JP
Inventors: 伸二森宗
Original assignee: Ryobi Ltd
Current assignee: Ryobi Ltd
Priority date: 2001-09-06
Filing date: 2001-09-06
Publication date: 2007-07-11
Anticipated expiration: 2021-09-06
Also published as: JP2003088052A

Description

【０００１】
【発明の属する技術分野】
本発明は、電動工具等の各種機器に装着されるモータのブラシホルダの取付構造に関する。
【０００２】
【従来の技術】
従来、例えば電動工具のハウジング内にモータを取り付ける場合、ハウジングを二つ割りに成形し、この二つの半割り部分でモータを挟み込むようにしており、モータのブラシホルダについても同様にハウジングの二つの半割り部分で挟み込んで支持している。図４はブラシホルダの支持構造の一例を示しており、このブラシホルダ１はハウジングの片方の半割り部分２に形成されたリブ３に押し付けられ、このリブ３と図示しないハウジングの他方の半割り部分に形成されたリブとで挟持される。
【０００３】
また、特開２０００−３２４７６６が開示する電動パワーステアリング装置においては、ハウジングとブラシホルダとの間に弾性部材が緩衝材として挟み込まれている。この緩衝材により、ハウジングからブラシホルダへの振動やブラシ摺動音が吸収される。
【０００４】
【発明が解決しようとする課題】
図４に示したようにハウジングの二つの半割り部分２でブラシホルダ１を挟んで固定しようとすると、特にハウジングが成形品である場合にはリブ３を用いてブラシホルダ１を固定するので、組立時に電機子４との間にズレが発生しやすいという問題がある。
【０００５】
また、特開２０００−３２４７６６の場合は、ブラシホルダが振動により変位する可能性があり、特に共振点が低いためモータが低速回転時に共振する可能性がある。
【０００６】
従って、本発明は、電動工具等においてブラシホルダのズレやブラシホルダの振動を低減し、ブラシと電機子の整流子との接触を良好にして整流特性を改善することを目的とする。
【０００７】
【課題を解決するための手段】
上記課題を解決するため、請求項１に係る発明は、二つ割構造のハウジング（５）に電動モータを内蔵した電動工具におけるブラシホルダ取付構造であって、前記電動モータの整流子（１１）を挿入するための貫通孔を有し、前記整流子に接触するブラシ（１２）が装着される環状の基板部（１４）からなるブラシホルダ（１３）と、前記ブラシホルダを一方の前記ハウジングに孔部（２３）を介して固定する固定具（２２）と、を備え、前記一方のハウジングには、前記ブラシホルダの位置決めを行う位置決め部（２１）が形成され、前記ブラシホルダは、前記位置決め部と係合する係合部（２５）を有する前記一方のハウジングに取り付けるための取付用突起部（２０）を備え、前記位置決め部と係合部は、前記孔部と同一軸線上に形成されており、前記係合部が前記位置決め部と係合したうえで前記取付用突起部が前記一方のハウジングに前記固定具によって取り付けられているブラシホルダの取付構造を採用する。
【０００８】
また、請求項２に係る発明は、上記ハウジング（５）の位置決め部（２１）が凸部（２６）又は凹部に形成されると共に、上記ブラシホルダ（１３）の係合部が上記凸部（２６）又は凹部と嵌合する凹部（２５）又は凸部に形成された請求項１記載のブラシホルダの取付構造を採用する。
【０００９】
また、請求項３に係る発明は、上記ハウジング（５）の位置決め部（２１）と上記ブラシホルダ（１３）の係合部（２５）が複数形成された請求項１記載のブラシホルダ取付構造を採用する。
【００１０】
【発明の実施の形態】
次に、本発明の実施の形態について図面を参照して説明する。
【００１１】
図１及び図２に例示されるハウジング５は電動工具用のものであり、このハウジング５はその中心軸を含む垂直面上で二分割された状態で成形される。そして、この分割された二つの半割り部分５ａ，５ｂが分割面上で組み合わされ、図示しない結合ネジにより結合されることにより完成したハウジング５とされる。
【００１２】
図１に示すように、ハウジング５内にはモータが収納され、このモータの磁石からなる固定子６がハウジング５の内壁面に固定される。また、モータの回転軸７がハウジング５内に固定された軸受８に支持される。ただし、回転軸７の他端を支持する軸受は図示していない。回転軸７には電機子９とモータを冷却するためのファン１０が取り付けられている。電機子９の整流子１１は回転軸７上の軸受８とファン１０との間に配置されている。
【００１３】
また、整流子１１に接触するブラシ１２，１２がブラシホルダ１３を介しハウジング５内に取り付けられている。
【００１４】
ブラシホルダ１３は、図３に示すように、中央に穴があいた円盤状の基板部１４を備える。この基板部１４は、図１及び図２に示すように、ハウジング５内にモータの回転軸７を横切るごとく配置され、ハウジング５の内側にリブ状に形成された隔壁１５に当てられる。この基板部１４と隔壁１５の中央の穴を電機子９の整流子１１が貫通する。隔壁１５はファン１０の回転で生ずる空気の流れをハウジング５の外部に効率的に排気するためのものであるが、ブラシホルダ１３の組立時にブラシホルダ１３の位置を仮決めするためのリブとしても機能する。
【００１５】
図１乃至図３に示すように、ブラシホルダ１３の基板部１４における隔壁１５と反対側の面上には、略円筒状の補強壁１６がモータの整流子１１を囲むように形成され、一対のブラシ装着部１７，１７が相対向するように形成される。各ブラシ装着部１７はそのトンネル状の穴が整流子１１に臨むように伸びる筒体として形成され、基板部１４と補強壁１６の双方に跨るように形成される。各ブラシ装着部１７の内部にはブラシ１２がそれぞれスライド可能に挿入され、各ブラシ１２は押えバネ１８により先端が整流子１１の周面に常時当接するように付勢される。基板部１４にはこの押えバネ１８を装着するためのバネ受け１９が取り付け手段として凸状に形成されている。
【００１６】
また、ブラシホルダ１３には、このブラシホルダ１３をハウジング５に固定するための取付用突起部２０が設けられ、ハウジング５には、ブラシホルダ１３をハウジング５に位置決めするための位置決め部２１が形成される。
【００１７】
さらに、この実施の形態では二個の取付用突起部２０，２０が形成されている。この二個の取付用突起部２０，２０が、ブラシホルダ１３の基板部１４に一対のブラシ装着部１７，１７と９０度だけ位相がずれるように形成される。各取付用突起部２０は基板部１４上から補強壁１６に沿って整流子１１の軸方向に平行に突出し、整流子１１の軸方向と直角な方向に固定ネジ２２を通すための挿入穴２３を有する。
【００１８】
ハウジング５の位置決め部２１はブラシホルダ１３の取付用突起部２０に対応して設けられる。この位置決め部２１はハウジング５の片方の半割り部分５ａに設けられ、取付用突起部２０が当接する端面を有したリブとして形成される。また、位置決め部２１の取付用突起部２０の臨む箇所には、取付用突起部２０の挿入穴２３に連通するネジ穴２４を備える。固定ネジ２２が取付用突起部２０の挿入穴２３を貫通しネジ穴２４の雌ネジと螺合することにより、ブラシホルダ１３はハウジング５に動かないように固定される。
【００１９】
上記ブラシホルダ１３の取付用突起部２０には、ハウジング５の位置決め部２１と係合する係合部が形成される。取付用突起部２０の係合部がハウジング５の位置決め部２１と係合することで、ブラシホルダ１３ひいてはブラシ１２が整流子１１に対して正確に位置決めされる。
【００２０】
係合部は具体的には凹部２５であり、取付用突起部２０における上記ハウジング５の位置決め部２１側に挿入穴２３に連通するように形成される。一方、ハウジング５の位置決め部２１には、この凹部２５に嵌まり込む凸部２６がネジ穴２４を囲むように形成される。凸部２６の先端は凹部２５の底面２５ａが当接する座面２６ａとして形成され、凸部２６の座面２６ａに凹部２５の底面２５ａが当たることによりブラシホルダ１３はハウジング５に対して正確に位置決めされ、ブラシホルダ１３と整流子１１の中心軸同士が合致することになる。この凹凸部２５，２６が係合したうえで固定ネジ２２が挿入穴２３を貫通しネジ穴２４の雌ネジと螺合することでブラシホルダ１３はハウジング５に対し正確に位置決めされた状態で固定され一体化される。この実施の形態では凹部２５が係合部側に形成され、凸部２６が位置決め部２１側に形成されるが、凹部２５を位置決め部２１側に形成し凸部２６を取付用突起部２０側に形成してもよい。
【００２１】
また、ハウジング５の位置決め部２１とブラシホルダ１３の係合部は、望ましくはこの実施の形態のように二箇所に形成されるが、必要に応じて三箇所以上又は一箇所にのみ形成してもよい。ハウジング５の位置決め部２１とブラシホルダ１３の係合部を一箇所にのみ形成する場合は、一方の取付用突起部２０をハウジングの二つの半割り部分５ａ，５ｂで挟持するように形成すればよい。この場合には、固定ネジ２２による固着は一箇所だけでよいので組み立て作業が簡易化される。ハウジング５の位置決め部２１とブラシホルダ１３の係合部を三箇所以上にわたって形成する場合には、ブラシホルダ１３をハウジング５により強固に固定し、整流特性をさらに高めることが可能である。
【００２２】
その他、ブラシホルダ１３の基板部１４上には各ブラシ装着部１７に対応して配線ピン２７，２７が突設され、ブラシ１２に結線されたリード線２８，２８が各配線ピン２７に係止される。このリード線２８，２８によりブラシホルダ１３とブラシ１２を経由して電機子９に電気が供給される。
【００２３】
次に、上記構成のブラシホルダの取付構造の組み立て手順の一例について説明する。
【００２４】
ブラシホルダ１３のブラシ装着部１７，１７にブラシ１２，１２を挿入し、押えバネ１８，１８によりブラシ１２，１２をその後部から押える。ブラシ１２，１２には予めリード線２８，２８をつないでおき、このリード線２８，２８を各配線ピン２７，２７に係止する。
【００２５】
このブラシホルダ１３をハウジング５の一方の半割り部分５ａに嵌め込み、ブラシホルダ１３の基板部１４をハウジング５の隔壁１５に当接させ、ブラシホルダ１３の仮位置決めを行う。続いてブラシホルダ１３の基板部１４を隔壁１５に沿って滑らせつつブラシホルダ１３の係合部の凹部２５内にハウジング５の位置決め部２１の凸部２６を嵌め込み、ブラシホルダ１３のハウジング５の半割り部分５ａに対する位置決めを行う。ブラシホルダ１３は凹部２５の底面２５ａと凸部２６の座面２６ａとを基準面としてハウジング５に正確に位置決めされる。
【００２６】
また、このブラシホルダ１３の取り付けに前後して軸受８、固定子６、電機子９等の装着も行う。
【００２７】
さらに、固定ネジ２２をブラシホルダ１３の取付用突起部２０における挿入穴２３から挿入し、ハウジング５のネジ穴２４の雌ネジと螺合させる。これにより、ブラシホルダ１３はハウジング５の半割り部分５ａに位置決めされた状態でガタつかないよう固定される。
【００２８】
その後、ハウジング５の他の半割り部分５ｂがブラシホルダ１３の固定された半割り部分５ａに対して当てられ、図示しない結合ネジにより半割り部分５ａ，５ｂ同士が結合される。かくて、電機子９の整流子１１はブラシホルダ１３に中心軸が一致するように配置されることとなり、整流子１１とブラシ１２とが円滑に接触し、振動等の発生が防止される。
【００２９】
【発明の効果】
請求項１に係る発明によれば、二つ割構造のハウジング５に電動モータを内蔵した電動工具におけるブラシホルダ取付構造であって、前記電動モータの整流子１１を挿入するための貫通孔を有し、前記整流子に接触するブラシ１２が装着される環状の基板部１４からなるブラシホルダ１３と、前記ブラシホルダ１３を一方の前記ハウジング５に孔部２３を介して固定する固定具２２と、を備え、前記一方のハウジング５には、前記ブラシホルダ１３の位置決めを行う位置決め部２１が形成され、前記ブラシホルダ１３は、前記位置決め部２１と係合する係合部２５を有する前記一方のハウジング５に取り付けるための取付用突起部２０を備え、前記位置決め部２１と係合部２５は、前記孔部２３と同一軸線上に形成されており、前記係合部２５が前記位置決め部２１と係合したうえで前記取付用突起部２０が前記一方のハウジング５に前記固定具２２によって取り付けられているブラシホルダの取付構造であるから、ブラシホルダがハウジングに正確にかつ強固に固着される。従って、ブラシホルダの倒れや電機子に対する位置ずれが防止されると共にブラシホルダの固有振動が高まることによってブラシホルダの振動が低下し、ブラシホルダに装着されるブラシと電機子の整流子との接触が良好となり、ブラシの摩耗が減少すると共に、整流火花が減少し、さらに発熱も減少し、総じて整流特性が向上する。
【００３０】
請求項２に係る発明によれば、上記ハウジングの位置決め部が凸部又は凹部に形成されると共に、上記ブラシホルダの係合部が上記凸部又は凹部と嵌合する凹部又は凸部に形成された請求項１記載のブラシホルダの取付構造であるから、ブラシホルダの組付け位置を正確に定めることが可能であり、整流特性がより一層向上する。
【００３１】
請求項３に係る発明によれば、上記ハウジングの位置決め部と上記ブラシホルダの係合部が複数形成された請求項１記載のブラシホルダ取付構造であるから、ブラシホルダの組付け位置を更に正確に定めることが可能であると共に、ブラシホルダをハウジングに更に強固に固定することが可能であり、整流特性が更に向上する。
【図面の簡単な説明】
【図１】本発明に係るブラシホルダの取付構造を、ハウジングの片方の半割り部を除いて示す立面図である。
【図２】図１中、ＩＩ−ＩＩ線矢視断面図であり、ハウジングの双方の半割り部を合致させて示す。
【図３】ブラシホルダの斜視図である。
【図４】従来のブラシホルダの取付構造を示す縦断面図である。
【符号の説明】
５…ハウジング
１３…ブラシホルダ
２０…取付用突起部
２１…位置決め部
２５…凹部
２６…凸部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting structure for a brush holder of a motor mounted on various devices such as an electric tool.
[0002]
[Prior art]
Conventionally, when a motor is mounted in a housing of an electric tool, for example, the housing is molded in half, and the motor is sandwiched between the two halves, and the motor brush holder is similarly divided into two halves of the housing. It is supported by being sandwiched between parts. FIG. 4 shows an example of a support structure of the brush holder. The brush holder 1 is pressed against a rib 3 formed on one half portion 2 of the housing, and the rib 3 and the other half portion of the housing (not shown) are pressed. It is sandwiched between ribs formed in the part.
[0003]
Moreover, in the electric power steering apparatus disclosed in Japanese Patent Laid-Open No. 2000-324766, an elastic member is sandwiched as a cushioning material between the housing and the brush holder. The shock absorbing material absorbs vibration from the housing to the brush holder and brush sliding sound.
[0004]
[Problems to be solved by the invention]
As shown in FIG. 4, when the brush holder 1 is sandwiched and fixed between the two halves 2 of the housing, the brush holder 1 is fixed using the ribs 3 particularly when the housing is a molded product. There is a problem that a gap is easily generated between the armature 4 and the armature 4 during assembly.
[0005]
In the case of Japanese Patent Laid-Open No. 2000-324766, there is a possibility that the brush holder is displaced by vibration. In particular, since the resonance point is low, the motor may resonate during low-speed rotation.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce brush holder displacement and brush holder vibration in an electric tool or the like, to improve contact between the brush and the armature commutator, and to improve commutation characteristics.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is a brush holder mounting structure in an electric tool in which an electric motor is built in a housing (5) having a split structure, and the commutator (11) of the electric motor. A brush holder (13) having a through hole for inserting a brush (12) on which a brush (12) in contact with the commutator is mounted, and the brush holder in one of the housings A fixing tool (22) that is fixed via a hole (23), and the one housing is formed with a positioning part (21) for positioning the brush holder, and the brush holder A mounting projection (20) for mounting on the one housing having an engaging portion (25) that engages with the portion, wherein the positioning portion and the engaging portion are formed on the same axis as the hole portion. It is, to adopt a mounting structure of the brush holder in which the engaging portion is the mounting projections after having engaged with the positioning portion is attached by the fastener on the one housing.
[0008]
In the invention according to claim 2, the positioning part (21) of the housing (5) is formed in the convex part (26) or the concave part, and the engaging part of the brush holder (13) is the convex part ( 26) or the mounting structure of the brush holder according to claim 1, wherein the mounting structure is formed in a recess (25) or a protrusion that fits into the recess.
[0009]
The invention according to claim 3 is the brush holder mounting structure according to claim 1, wherein a plurality of positioning portions (21) of the housing (5) and engaging portions (25) of the brush holder (13) are formed. adopt.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0011]
The housing 5 illustrated in FIGS. 1 and 2 is for a power tool, and the housing 5 is formed in a state of being divided into two parts on a vertical plane including its central axis. Then, the divided two halved parts 5a and 5b are combined on the dividing surface, and are combined by a connecting screw (not shown) to form a completed housing 5.
[0012]
As shown in FIG. 1, a motor is accommodated in the housing 5, and a stator 6 made of a magnet of the motor is fixed to the inner wall surface of the housing 5. Further, the rotating shaft 7 of the motor is supported by a bearing 8 fixed in the housing 5. However, the bearing which supports the other end of the rotating shaft 7 is not illustrated. An armature 9 and a fan 10 for cooling the motor are attached to the rotary shaft 7. The commutator 11 of the armature 9 is disposed between the bearing 8 on the rotating shaft 7 and the fan 10.
[0013]
Further, brushes 12, 12 that are in contact with the commutator 11 are mounted in the housing 5 via a brush holder 13.
[0014]
As shown in FIG. 3, the brush holder 13 includes a disk-shaped substrate portion 14 having a hole in the center. As shown in FIGS. 1 and 2, the substrate portion 14 is disposed in the housing 5 so as to cross the rotation shaft 7 of the motor, and is applied to a partition wall 15 formed in a rib shape inside the housing 5. The commutator 11 of the armature 9 passes through the central hole of the substrate portion 14 and the partition wall 15. The partition wall 15 is for efficiently exhausting the air flow generated by the rotation of the fan 10 to the outside of the housing 5, but it can also be used as a rib for temporarily determining the position of the brush holder 13 when the brush holder 13 is assembled. Function.
[0015]
As shown in FIGS. 1 to 3, a substantially cylindrical reinforcing wall 16 is formed on the surface of the substrate portion 14 of the brush holder 13 opposite to the partition wall 15 so as to surround the commutator 11 of the motor. The brush mounting portions 17 and 17 are formed so as to face each other. Each brush mounting portion 17 is formed as a cylindrical body extending so that the tunnel-shaped hole faces the commutator 11, and is formed so as to straddle both the substrate portion 14 and the reinforcing wall 16. The brush 12 is slidably inserted into each brush mounting portion 17, and each brush 12 is urged by a presser spring 18 so that the tip always contacts the peripheral surface of the commutator 11. A spring receiver 19 for mounting the presser spring 18 is formed on the substrate portion 14 in a convex shape as an attaching means.
[0016]
The brush holder 13 is provided with a mounting projection 20 for fixing the brush holder 13 to the housing 5, and the housing 5 is formed with a positioning portion 21 for positioning the brush holder 13 on the housing 5. Is done.
[0017]
Further, in this embodiment, two mounting projections 20 and 20 are formed. The two mounting projections 20 and 20 are formed on the base plate part 14 of the brush holder 13 so that the phase is shifted by 90 degrees from the pair of brush mounting parts 17 and 17. Each mounting projection 20 protrudes from the board portion 14 along the reinforcing wall 16 in parallel with the axial direction of the commutator 11, and an insertion hole 23 for passing the fixing screw 22 in a direction perpendicular to the axial direction of the commutator 11. Have
[0018]
The positioning portion 21 of the housing 5 is provided corresponding to the mounting projection 20 of the brush holder 13. The positioning portion 21 is provided in one half portion 5a of the housing 5 and is formed as a rib having an end surface with which the mounting projection 20 abuts. Further, a screw hole 24 that communicates with the insertion hole 23 of the mounting projection 20 is provided at a location where the mounting projection 20 of the positioning portion 21 faces. When the fixing screw 22 passes through the insertion hole 23 of the mounting projection 20 and is screwed with the female screw of the screw hole 24, the brush holder 13 is fixed to the housing 5 so as not to move.
[0019]
An engaging portion that engages with the positioning portion 21 of the housing 5 is formed on the mounting projection 20 of the brush holder 13. When the engaging portion of the mounting projection 20 is engaged with the positioning portion 21 of the housing 5, the brush holder 13 and the brush 12 are accurately positioned with respect to the commutator 11.
[0020]
Specifically, the engaging portion is a recess 25 and is formed on the mounting projection 20 on the positioning portion 21 side of the housing 5 so as to communicate with the insertion hole 23. On the other hand, the positioning portion 21 of the housing 5 is formed with a convex portion 26 that fits into the concave portion 25 so as to surround the screw hole 24. The tip of the convex portion 26 is formed as a seating surface 26 a with which the bottom surface 25 a of the concave portion 25 abuts, and the bottom surface 25 a of the concave portion 25 abuts against the seating surface 26 a of the convex portion 26 so that the brush holder 13 is accurately positioned with respect to the housing 5. Thus, the central axes of the brush holder 13 and the commutator 11 coincide with each other. After the concavo-convex portions 25 and 26 are engaged, the fixing screw 22 passes through the insertion hole 23 and engages with the female screw of the screw hole 24 so that the brush holder 13 is fixed in a state where it is accurately positioned with respect to the housing 5. And integrated. In this embodiment, the concave portion 25 is formed on the engaging portion side and the convex portion 26 is formed on the positioning portion 21 side. However, the concave portion 25 is formed on the positioning portion 21 side and the convex portion 26 is formed on the mounting projection portion 20 side. You may form in.
[0021]
Further, the positioning portion 21 of the housing 5 and the engaging portion of the brush holder 13 are desirably formed at two locations as in this embodiment, but may be formed at three or more locations or only at one location as required. Also good. In the case where the engaging portion between the positioning portion 21 of the housing 5 and the brush holder 13 is formed only at one place, if one mounting projection 20 is formed so as to be sandwiched between the two halved portions 5a and 5b of the housing. Good. In this case, since the fixing with the fixing screw 22 is only required at one place, the assembling work is simplified. When the engaging portion between the positioning portion 21 of the housing 5 and the brush holder 13 is formed at three or more locations, the brush holder 13 can be firmly fixed by the housing 5 and the rectification characteristics can be further enhanced.
[0022]
In addition, wiring pins 27 and 27 project from the substrate portion 14 of the brush holder 13 corresponding to the brush mounting portions 17, and the lead wires 28 and 28 connected to the brush 12 are locked to the wiring pins 27. Is done. Electricity is supplied to the armature 9 via the brush holder 13 and the brush 12 by the lead wires 28 and 28.
[0023]
Next, an example of an assembly procedure of the brush holder mounting structure having the above-described configuration will be described.
[0024]
The brushes 12 and 12 are inserted into the brush mounting portions 17 and 17 of the brush holder 13, and the brushes 12 and 12 are pressed from the rear portions by the pressing springs 18 and 18. Lead wires 28 and 28 are connected in advance to the brushes 12 and 12, and the lead wires 28 and 28 are locked to the wiring pins 27 and 27.
[0025]
The brush holder 13 is fitted into one half portion 5 a of the housing 5, the substrate portion 14 of the brush holder 13 is brought into contact with the partition wall 15 of the housing 5, and the brush holder 13 is temporarily positioned. Subsequently, the convex portion 26 of the positioning portion 21 of the housing 5 is fitted into the concave portion 25 of the engaging portion of the brush holder 13 while sliding the substrate portion 14 of the brush holder 13 along the partition wall 15. Positioning with respect to the half portion 5a is performed. The brush holder 13 is accurately positioned in the housing 5 with the bottom surface 25a of the concave portion 25 and the seating surface 26a of the convex portion 26 as reference surfaces.
[0026]
In addition, the bearing 8, the stator 6, the armature 9 and the like are also mounted before and after the attachment of the brush holder 13.
[0027]
Further, the fixing screw 22 is inserted from the insertion hole 23 in the mounting projection 20 of the brush holder 13 and screwed into the female screw of the screw hole 24 of the housing 5. Thereby, the brush holder 13 is fixed so as not to rattle in a state where the brush holder 13 is positioned in the half portion 5 a of the housing 5.
[0028]
Thereafter, the other half portion 5b of the housing 5 is applied to the half portion 5a to which the brush holder 13 is fixed, and the half portions 5a and 5b are coupled to each other by a coupling screw (not shown). Thus, the commutator 11 of the armature 9 is arranged so that the central axis thereof coincides with the brush holder 13, and the commutator 11 and the brush 12 are smoothly in contact with each other, so that generation of vibrations and the like is prevented.
[0029]
【The invention's effect】
According to the first aspect of the present invention, there is provided a brush holder mounting structure in an electric tool in which an electric motor is incorporated in a housing 5 having a split structure, and a through hole for inserting the commutator 11 of the electric motor is provided. A brush holder 13 comprising an annular substrate portion 14 to which a brush 12 that contacts the commutator is mounted; a fixture 22 that fixes the brush holder 13 to one of the housings 5 through a hole 23; The one housing 5 is formed with a positioning portion 21 for positioning the brush holder 13, and the brush holder 13 has an engaging portion 25 that engages with the positioning portion 21. 5, the positioning projection 21 and the engagement portion 25 are formed on the same axis as the hole 23, and the engagement portion 2. Accurately and because There is a mounting structure of a brush holder in which the positioning part 21 and the engaging said attachment projections 20 after having engaged is attached by the fixture 22 to the housing 5 of the one brush holder to the housing Firmly fixed. Therefore, the brush holder is prevented from falling or being displaced with respect to the armature, and the vibration of the brush holder is reduced by increasing the natural vibration of the brush holder, so that the brush mounted on the brush holder is in contact with the commutator of the armature. As a result, the wear of the brush is reduced, the rectification spark is reduced, the heat generation is also reduced, and the rectification characteristics are generally improved.
[0030]
According to the invention which concerns on Claim 2, while the positioning part of the said housing is formed in a convex part or a recessed part, the engaging part of the said brush holder is formed in the recessed part or convex part which fits the said convex part or a recessed part. Since it is the attachment structure of the brush holder of Claim 1, the assembly position of a brush holder can be defined correctly and a rectification | straightening characteristic improves further.
[0031]
According to the invention of claim 3, since the brush holder mounting structure according to claim 1 is provided with a plurality of positioning portions of the housing and engaging portions of the brush holder, the assembly position of the brush holder is more accurate. In addition, the brush holder can be more firmly fixed to the housing, and the rectification characteristics are further improved.
[Brief description of the drawings]
FIG. 1 is an elevational view showing a mounting structure of a brush holder according to the present invention except for one half of a housing.
FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and shows both halves of the housing in alignment.
FIG. 3 is a perspective view of a brush holder.
FIG. 4 is a longitudinal sectional view showing a conventional brush holder mounting structure.
[Explanation of symbols]
5 ... Housing 13 ... Brush holder 20 ... Mounting projection 21 ... Positioning portion 25 ... Concave portion 26 ... Convex portion

Claims

A brush holder mounting structure in an electric tool incorporating an electric motor in a two-part housing,
A brush holder having a through-hole for inserting the commutator of the electric motor, and comprising an annular substrate portion to which a brush contacting the commutator is mounted;
A fixture for fixing the brush holder to one of the housings through a hole;
With
In the one housing,
A positioning part for positioning the brush holder is formed,
The brush holder is
A mounting projection for mounting on the one housing having an engaging portion that engages with the positioning portion;
The positioning portion and the engaging portion are formed on the same axis as the hole portion, and the engaging projection is engaged with the positioning portion, and the mounting projection is attached to the one housing. The mounting structure of the brush holder characterized by being attached by .

The positioning portion of the housing is formed in a convex portion or a concave portion, and the engaging portion of the brush holder is formed in a concave portion or a convex portion that fits into the convex portion or the concave portion. Brush holder mounting structure.

The brush holder mounting structure according to claim 1, wherein a plurality of positioning portions of the housing and engaging portions of the brush holder are formed.