JP2004293657A

JP2004293657A - Reduction gear for small motor

Info

Publication number: JP2004293657A
Application number: JP2003086647A
Authority: JP
Inventors: Naoji Sato; 尚次佐藤
Original assignee: Nidec Servo Corp
Current assignee: Nidec Advanced Motor Corp
Priority date: 2003-03-27
Filing date: 2003-03-27
Publication date: 2004-10-21
Anticipated expiration: 2023-03-27
Also published as: JP3891570B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction gear for a small motor composed of plastic gears with double end supported structure of bearings having a plurality of engagement positions to compensate defects in a conventional gear structure allowing only one position of simultaneous gear engagement, while taking advantages of a planetary gear mechanism allowing a plurality of positions of simultaneous gear engagement, with an output shaft positioned at a center of the reduction gear. <P>SOLUTION: In this reduction gear, a plurality of follower gears are disposed around a drive gear, so that a plurality of gear engagement positions can be set for one stage of reduction. Bearings to support the output shaft are disposed on a front case and a rear case to compose the double end support structure. A rear part of the output shaft is used as a gear shaft, and intermediate gears are rotatably supported. In addition, a plurality of gears are disposed on a plurality of gear shafts disposed in parallel to the output shaft. In this constitution, the reduction gear for a small motor is composed using the plastic gears equivalent to metal gears in strength. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【産業上の利用分野】
本発明は、事務用機器、電子計算機用周辺機器、家電機器あるいは医療機器などに広く用いられている減速機付小形モータの減速機構造に関するものである。
【０００２】
【従来の技術】
減速機付小形モータは事務用機器や医療機器などに広く普及するに伴い、小形化、高精度化、低騒音化、低価額化等が要求されている。
この減速機付小形モータの減速機を構成する歯車にプラスチック材料を使用する事により低騒音化、低価額化をはかっている。
【０００３】
図１２に従来の減速機付小形モータの外観図を、図１３に図１２のＦ１−Ｆ２断面図で歯車噛合状況を示す。図１４に図１３のＧ１−Ｇ２−Ｇ３−Ｇ４−Ｇ５−Ｇ６−Ｇ７歯車展開断面図を示す。
図１２において小形モータ１に減速機２が直結され、出力軸３より小形モータの動力が負荷に伝達される。
図１４において小形モータ１の動力は、モータ出力軸２０に結合されたモータ歯車２１から２番歯車組立２２の２番大歯車２３に伝達されることにより減速器に伝えられる。次に２番歯車組立２２の２番小歯車２４と３番歯車組立２５の３番大歯車２６と噛合い、順次３番小歯車２７、４番大歯車２９、４番小歯車３０、出力歯車３２、出力軸３に伝えられる。この時２番歯車組立２２、３番歯車組立２５、４番歯車組立２８は、前ケ−ス３３と後ケ−ス３４に平行且つ所定の間隔で固定された２番軸３５、３番軸３６、４番軸３７で支えられ、出力歯車組立３１は前ケース３３に固定された前側軸受３８と後ケース３４に固定された後側軸受３９で回転自在に保持されている。そしてモータ歯車２１と２番大歯車２３、２番小歯車２４と３番大歯車２６、３番小歯車２７と４番大歯車２９、更に４番小歯車３０と出力歯車３２はそれぞれ一個所ずつ噛合っている。
この様な歯車配列の減速器においては、従来の金属材料を用いた歯車構成に比べ、低騒音化、低価額化をはかるためプラスチック材料を用いると歯車の強度が低下すると言う問題が発生する事がある。
【０００４】
前述の減速機付小形モータの減速機を構成する歯車材料には、一般的に軟鋼などの金属材料が用いられている。この軟鋼の引張強度は３９２［ＭＰａ］であり、一方歯車に用いられるプラスチック材料の一例であるポリアセタールの引張強度は６７〜８３［ＭＰａ］程度である。したがってこのポリアセタールを用いたプラスチック歯車は金属歯車に比べ歯車強度が約４．８分の一から約５．８分の一に低下することになる。
この様にプラスチック歯車を用いた場合の歯車強度の低下を補う為に、歯車の噛合歯幅を増加することが有効であるが、あまり歯幅を広くするとプラスチックで成形された歯車の歯筋誤差の影響で、かえって歯車の噛合精度が低下し歯車騒音が高くなる事がある。したがってプラスチック歯車においては歯幅を余り広くすることができないと言う欠点が現れる。
【０００５】
【特許文献１】特開平１０−３１１３８４遊星歯車減速機及びその組立方法
特許文献１では一つの太陽歯車に三つの遊星歯車が噛合い、またこの三つの遊星歯車に一つの内歯車が噛合って動力を伝達している。
【０００６】
前述の様に、図１２、図１３、図１４で述べられた従来の歯車構成の減速機では、通常の歯車噛合個所は常に一個所である。従ってプラスチック歯車を用いると歯車強度が低下する欠点がある。また歯車歯幅をあまり広くすると歯筋誤差の影響で歯車騒音が大きくなる欠点がある。
更にモータ軸の中心と出力軸の中心が一致していない為、減速機の負荷装置への取付け面積が増加すると言う欠点がある。しかしながら歯車組立の両側で各歯車組立を支持しているので、両端支持構造となり減速機の剛性増加に役立っている。
特許文献１で述べられた遊星歯車減速機を用いて同時噛合い個所を複数個所にする事により歯車強度を上げることも有効な方法である。
しかしながらこの遊星歯車減速機の場合には、出力軸が片持支持構造となるので二個の軸受を直列に装着している。したがって軸受部分が大きくなり、減速器が長くなる等の欠点があるが、モータ軸の中心と減速機の出力軸の中心が一致しているので、負荷装置への取付け面積が小さいと言う長所がある。
【０００７】
前述の様に本発明においては、遊星歯車減速機の長所である「複数の同時噛合い個所と中心出力軸」、及び従来減速機の長所である「両端支持構造」を合せ持ったプラスチック歯車を用いた減速機を提案するものである。
【０００８】
【発明が解決しようとする課題】
小形減速機付小形モータが広範囲に用いられる様になり、減速機付小形モ−タに使用される減速機においても小形化、軽量化、高強度化、低価額化の要求が高まっている。
本発明においては、「遊星歯車機構の同時噛合い個所は複数個所で、出力軸は減速機の中心位置にある」と言う長所を活かして、「従来の歯車機構の同時噛合い個所は一個所である」と言う欠点を補った「軸受が両端支持構造で、同時噛合い個所を複数個所にしたプラスチック歯車で構成され、しかも出力軸が中心に位置している事を特徴とした減速機」を提案する事が課題である。
【０００９】
【課題を解決するための手段】
本発明に成る減速機は駆動歯車の外周に従動歯車を複数個配置し、減速１段当りの歯車の噛合い個所を複数個所としている。出力軸を支持する軸受を前ケースと後ケ−スに配置しいわゆる両端支持構造とし、出力軸の後部を歯車軸として使用し中間歯車を回転自在に支持している。更に出力軸に平行に配置した複数個の歯車軸に複数個の歯車を積重ねて配置している。
【００１０】
【作用】
上述の如き構成においては、噛合個所が複数個所となるため歯車強度を増加する事が出来る。従って歯車強度の低いプラスチック歯車を使用することが可能となる。また出力軸及び歯車軸が前ケース及び後ケースの二個所で支えられ、両端支持構造となっているので、出力軸及び歯車軸はベンディング荷重等に耐える構造となっている。従って総合的にプラスチック歯車を用いて歯車強度を増加した減速機を提供する事ができる。
【００１１】
【実施例】
以下図面によって本発明の実施例を説明する。
図１は減速機付小形モータの右側面図に、本発明の減速機断面図を示したものであり、図２は減速機付小形モータの正面図である。図２におけるＣ１−Ｏ−Ｃ２の減速機部の断面を図１の減速機断面図に示している。
【００１２】
本発明に成る減速機の動力は、小形モータ５１に結合されたモータ歯車５２から２番歯車組立５３の２番大歯車５４に伝えられる。この２番大歯車５４と一体となった２番小歯車５５から、３番歯車組立５６の３番大歯車５７に伝えられる。この３番大歯車５７と一体となった３番小歯車５８から、４番歯車組立５９の４番大歯車６０に伝えられる。この４番大歯車６０と一体となった４番小歯車６１から出力歯車組立６２の出力歯車６３に伝えられる。この出力歯車６３と結合した出力軸６４から動力が負荷に伝えられる。そして出力軸６４は出力軸前部軸受８３と出力軸後部軸受８２に支持されている。
【００１３】
図３に図１のＡ１−Ａ２断面図を示す。減速初段では、モータ歯車５２と２個の２番歯車組立５３の２番大歯車５４が噛合っており、この２個の２番歯車組立５３は、前ケース８０と後ケース８１に固定された歯車軸７０に対して回転自在に組み立てられている。
【００１４】
図４に図１のＣ１−Ｃ２断面図を示す。減速２段目では、２個の２番歯車組立５３の２番小歯車５５は３番歯車組立５６の３番大歯車５７と噛合っており、１個の３番歯車組立５６は出力軸６４の反負荷側出力軸６５上を回転する。
【００１５】
図５に図１のＤ１−Ｄ２断面図を示す。減速３段目では、１個の３番歯車組立５６の３番小歯車５８は、４番歯車組立５９の４番大歯車６０と噛合っており、４個の４番歯車組立５９は４個の歯車軸７０上を回転する。
【００１６】
図６に図１のＥ１−Ｅ２断面図を示す。減速４段目では、４個の４番歯車組立５９の４番小歯車６１は、一個の出力歯車６３と噛合っており、４個の４番歯車組立５９は４個の歯車軸７０上を回転する。
【００１７】
図７に図１のＢ１−Ｂ２断面図を示す。後ケース８１に出力軸後部軸受８２が設けられ、反負荷側出力軸６５を支持している。
【００１８】
以上の説明から明らかの様に
減速初段におけるモータ歯車５２と２番大歯車５４の噛合個所は２個所、
減速２段目における２番小歯車５５と３番大歯車５７の噛合個所は２個所、
減速３段目における３番小歯車５８と４番大歯車６０の噛合個所は４個所、
減速４段目における４番小歯車６１と出力歯車６３の噛合個所は４個所、
２番歯車組立５３及び４番歯車組立５９を支える歯車軸７０の固定個所は２個所、
出力歯車６３及び３番歯車組立５６を支える出力軸６４の軸受は２個所となっている。
この様に減速の初段及び２段目は回転速度が速いが伝達トルクが小さいので噛合個所を２個所とし、減速が進み回転速度が遅く伝達トルクが大きくなる３段目、４段目では噛合個所を４個所としている。
一般に減速機の強度は、回転速度が遅く伝達トルクの大きい最終出力段の歯車強度で決められる。前述の様に本発明の減速機において出力歯車の噛合個所は４個所である。従って４番小歯車と出力歯車の噛合歯幅を１．５倍とすると、最終出力段の歯車強度は４個所×１．５倍＝６倍となる。したがって金属歯車に匹敵する強度を有するプラスチック歯車を得る事が出来る。
又特許文献１の遊星歯車減速機では最終出力段の出力軸は片持支持構造となっているが、本発明の減速機においては、最終出力段の出力軸と３番歯車組立及び２番歯車組立と４番歯車組立を支持する歯車軸は、前カバー及び後カバーの２個所で固定されている。
【００１９】
本発明の他の実施例として、図８に減速２段の減速機を示す。
本発明に成る減速機の動力は、小形モータ５１に結合されたモータ歯車５２から２番歯車組立９１の２番大歯車９２に伝えられる。この２番大歯車９２と一体となった２番小歯車９３から出力歯車組立９４の出力歯車９５に伝えられる。この出力歯車９５と結合した出力軸９６から動力が負荷に伝えられる。
【００２０】
また図９には減速６段の減速機を示す。
本発明に成る減速機の動力は、小形モータ５１に結合されたモータ歯車５２から２番歯車組立１０１の２番大歯車１０２に伝えられる。この２番大歯車１０２と一体となった２番小歯車１０３から、３番歯車組立１０４の３番大歯車１０５に伝えられる。この３番大歯車１０５と一体となった３番小歯車１０６から、４番歯車組立１０７の４番大歯車１０８に伝えられる。この４番大歯車１０８と一体となった４番小歯車１０９から、５番歯車組立１１０の５番大歯車１１１に伝えられる。この５番大歯車１１１と一体となった５番小歯車１１２から、６番歯車組立１１３の６番大歯車１１４に伝えられる。この６番大歯車１１４と一体となった６番小歯車１１５から出力歯車組立１１６の出力歯車１１７に伝えられる。この出力歯車１１７と結合した出力軸１１８から動力が負荷に伝えられる。従って図１と合わせて２段、４段、６段の減速機が可能となる。
【００２１】
更に本発明の他の実施例として、図１０に歯車軸２本を等配分の場合、図１１に歯車軸３本を等配分の場合を示す。
図１０では歯車軸が１８０度に配置され、２個所で歯車が噛合うので、２の倍数の歯車歯数を選定する。図１１では歯車軸が１２０度に配置され、３個所で歯車が噛合うので、３の倍数の歯車歯数を選定する。
この様にして奇数、偶数それぞれの歯数を用いて減速比を選定することが出来る。従って図５と合せ歯車の噛合個所を２個所、３個所、４個所と選定する事が出来る。
【００２２】
【発明の効果】
本発明の様に、各段の歯車の噛合個所を複数個所にすると共に、歯車の歯幅を増加することにより、金属歯車に匹敵する強度を有するプラスチック歯車用いた減速機付小形モータの減速機を提供することができる。更に減速機の出力軸の中心はモータ軸の中心と一致しているので、取付面積が小さくなる長所がある。
従って本発明によれば「遊星歯車機構の同時噛合い個所は複数個所で、出力軸は減速機の中心位置にある」と言う長所を活かして、「従来の歯車機構の同時噛合い個所は一個所である」と言う欠点を補った「軸受が両端支持構造で、同時噛合い個所を複数個所にしたプラスチック歯車で構成され、しかも出力軸が中心に位置している事を特徴とした減速機」を実現する事が出来る。
【図面の簡単な説明】
【図１】本発明による減速機付小形モータの右側面図における減速機断面図
【図２】本発明による減速機付小形モータの正面図
【図３】Ａ１−Ａ２断面図
【図４】Ｃ１−Ｃ２断面図
【図５】Ｄ１−Ｄ２断面図
【図６】Ｅ１−Ｅ２断面図
【図７】Ｂ１−Ｂ２断面図
【図８】減速２段の減速機
【図９】減速６段の減速機
【図１０】歯車軸が１８０度に配置されたもの
【図１１】歯車軸が１２０度に配置されたもの
【図１２】従来の減速機付小形モータの外観図
【図１３】Ｆ１−Ｆ２断面図
【図１４】従来の減速機付小形モータのＧ１−Ｇ７歯車展開断面図
【符号の説明】
１、５１小形モータ
２減速機
３、６４、９６、１１８出力軸
２０モータ出力軸
２１、５２モータ歯車
２２、５３、９１、１０１２番歯車組立
２３、５４、９２、１０２２番大歯車
２４、５５、９３、１０３２番小歯車
２５、５６、１０４３番歯車組立
２６、５７、１０５３番大歯車
２７、５８、１０６３番小歯車
２８、５９、１０７４番歯車組立
２９、６０、１０８４番大歯車
３０、６１、１０９４番小歯車
３１、６２、９４、１１６出力歯車組立
３２、６３、９５、１１７出力歯車
３３、８０前ケース
３４、８１後ケース
３５２番軸
３６３番軸
３７４番軸
３８前側軸受
３９後側軸受
６５反負荷側出力軸
７０歯車軸
８２出力軸後部軸受
８３出力軸前部軸受
１１０５番歯車組立
１１１５番大歯車
１１２５番小歯車
１１３６番歯車組立
１１４６番大歯車
１１５６番小歯車[0001]
[Industrial applications]
The present invention relates to a reduction gear structure of a small motor with a reduction gear widely used in office equipment, peripheral equipment for electronic computers, home appliances, medical equipment, and the like.
[0002]
[Prior art]
As small motors with reduction gears are widely used in office equipment and medical equipment, they are required to be downsized, highly accurate, low in noise, low in price, and the like.
By using a plastic material for the gear constituting the reduction gear of the small motor with a reduction gear, the noise and the cost are reduced.
[0003]
FIG. 12 is an external view of a conventional small motor with a reduction gear, and FIG. 13 is a sectional view taken along line F1-F2 in FIG. FIG. 14 is a developed sectional view of the G1-G2-G3-G4-G5-G6-G7 gear of FIG.
In FIG. 12, the reduction gear 2 is directly connected to the small motor 1, and the power of the small motor is transmitted from the output shaft 3 to the load.
In FIG. 14, the power of the small motor 1 is transmitted from the motor gear 21 coupled to the motor output shaft 20 to the second large gear 23 of the second gear assembly 22 to be transmitted to the speed reducer. Next, the second small gear 24 of the second gear assembly 22 and the third large gear 26 of the third gear assembly 25 are meshed with each other, and the third small gear 27, the fourth large gear 29, the fourth small gear 30, and the output gear are sequentially arranged. 32, transmitted to the output shaft 3. At this time, the second gear assembly 22, the third gear assembly 25, and the fourth gear assembly 28 are parallel to the front case 33 and the rear case 34 and fixed at a predetermined interval with a second shaft 35 and a third shaft. 36, the output gear assembly 31 is rotatably supported by a front bearing 38 fixed to the front case 33 and a rear bearing 39 fixed to the rear case 34. The motor gear 21 and the second large gear 23, the second small gear 24 and the third large gear 26, the third small gear 27 and the fourth large gear 29, and the fourth small gear 30 and the output gear 32 are respectively provided at one location. Meshing.
In the gear reducer having such a gear arrangement, there is a problem that the strength of the gear is lowered when a plastic material is used in order to reduce noise and cost compared to a gear configuration using a conventional metal material. There is.
[0004]
Generally, a metal material such as mild steel is used as a gear material constituting the reduction gear of the above-described small motor with a reduction gear. The tensile strength of this mild steel is 392 [MPa], while the tensile strength of polyacetal, which is an example of a plastic material used for gears, is about 67 to 83 [MPa]. Therefore, the gear strength of the plastic gear using this polyacetal is reduced from about 4.8 to about 5.8 compared to the metal gear.
In order to compensate for the reduction in gear strength when plastic gears are used in this way, it is effective to increase the meshing tooth width of the gears. As a result, the meshing accuracy of the gear may decrease and the gear noise may increase. Therefore, the plastic gear has a drawback that the tooth width cannot be increased too much.
[0005]
[Patent Document 1] JP-A-10-31384 Planetary gear reducer and its assembly method In Patent Document 1, three planetary gears mesh with one sun gear, and one internal gear meshes with these three planetary gears. Power is transmitted.
[0006]
As described above, in the speed reducer having the conventional gear configuration described in FIGS. 12, 13, and 14, there is always one normal gear meshing position. Therefore, when a plastic gear is used, there is a drawback that the gear strength is lowered. Further, if the gear tooth width is too wide, there is a drawback that gear noise increases due to the influence of tooth trace errors.
Further, since the center of the motor shaft and the center of the output shaft do not coincide with each other, there is a disadvantage that the mounting area of the reduction gear to the load device increases. However, since each gear assembly is supported on both sides of the gear assembly, a double-end support structure is provided, which helps increase the rigidity of the speed reducer.
It is also an effective method to increase the gear strength by using a planetary gear reducer described in Patent Document 1 to make a plurality of simultaneous meshing locations.
However, in the case of this planetary gear reducer, since the output shaft has a cantilever support structure, two bearings are mounted in series. Therefore, there is a disadvantage that the bearing part becomes large and the speed reducer becomes long, but the center of the motor shaft and the center of the output shaft of the speed reducer coincide with each other, so that the mounting area to the load device is small. is there.
[0007]
As described above, in the present invention, a plastic gear having both “a plurality of simultaneous meshing portions and a central output shaft” which is an advantage of a planetary gear speed reducer and “both end support structure” which is an advantage of a conventional speed reducer. The reduction gear used is proposed.
[0008]
[Problems to be solved by the invention]
Small motors with small reduction gears are used in a wide range, and reduction gears used in small motors with reduction gears are increasingly required to be smaller, lighter, stronger, and less expensive.
In the present invention, taking advantage of the fact that "the planetary gear mechanism has a plurality of simultaneous meshing locations and the output shaft is at the center of the speed reducer", "the conventional gear mechanism has one meshing location. "The speed reducer is characterized by the fact that the bearing has a double-sided support structure, is composed of plastic gears with multiple simultaneous meshing locations, and the output shaft is located at the center." It is a problem to propose.
[0009]
[Means for Solving the Problems]
In the reduction gear according to the present invention, a plurality of driven gears are arranged on the outer periphery of the drive gear, and a plurality of meshing locations of the gear per reduction gear are provided. Bearings for supporting the output shaft are arranged in a front case and a rear case to form a so-called both-end support structure, and the rear portion of the output shaft is used as a gear shaft to support the intermediate gear rotatably. Further, a plurality of gears are stacked on a plurality of gear shafts arranged in parallel with the output shaft.
[0010]
[Action]
In the configuration as described above, the gear strength can be increased because there are a plurality of meshing locations. Accordingly, it is possible to use a plastic gear having low gear strength. In addition, since the output shaft and the gear shaft are supported at two locations of the front case and the rear case and have a double-end support structure, the output shaft and the gear shaft have a structure that can withstand a bending load or the like. Therefore, it is possible to provide a speed reducer having a gear strength increased using plastic gears comprehensively.
[0011]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a right side view of a small motor with a reduction gear, and shows a cross-sectional view of the reduction gear of the present invention. FIG. 2 is a front view of the small motor with a reduction gear. The cross section of the reduction gear section of C1-O-C2 in FIG. 2 is shown in the reduction gear cross section of FIG.
[0012]
The power of the reduction gear according to the present invention is transmitted from the motor gear 52 coupled to the small motor 51 to the second large gear 54 of the second gear assembly 53. The second small gear 55 integrated with the second large gear 54 is transmitted to the third large gear 57 of the third gear assembly 56. This is transmitted from the third small gear 58 integrated with the third large gear 57 to the fourth large gear 60 of the fourth gear assembly 59. The fourth small gear 61 integrated with the fourth large gear 60 is transmitted to the output gear 63 of the output gear assembly 62. Power is transmitted to a load from an output shaft 64 coupled to the output gear 63. The output shaft 64 is supported by the output shaft front bearing 83 and the output shaft rear bearing 82.
[0013]
FIG. 3 is a cross-sectional view taken along the line A1-A2 of FIG. In the first reduction stage, the motor gear 52 and the second large gear 54 of the two second gear assemblies 53 are engaged with each other, and the two second gear assemblies 53 are fixed to the front case 80 and the rear case 81. It is assembled so as to be rotatable with respect to the gear shaft 70.
[0014]
FIG. 4 is a cross-sectional view taken along line C1-C2 of FIG. In the second reduction stage, the second small gear 55 of the two second gear assemblies 53 meshes with the third large gear 57 of the third gear assembly 56, and one third gear assembly 56 is connected to the output shaft 64. Rotate on the opposite load side output shaft 65 of the motor.
[0015]
FIG. 5 is a sectional view taken along the line D1-D2 of FIG. In the third reduction stage, the third small gear 58 of one third gear assembly 56 meshes with the fourth large gear 60 of the fourth gear assembly 59, and four four fourth gear assemblies 59 are four. The gear shaft 70 is rotated.
[0016]
FIG. 6 shows an E1-E2 cross-sectional view of FIG. In the fourth reduction stage, the fourth small gear 61 of the four fourth gear assemblies 59 meshes with one output gear 63, and the four fourth gear assemblies 59 move on the four gear shafts 70. Rotate.
[0017]
FIG. 7 shows a B1-B2 cross-sectional view of FIG. An output shaft rear bearing 82 is provided in the rear case 81 and supports the anti-load side output shaft 65.
[0018]
As is apparent from the above description, there are two meshing positions of the motor gear 52 and the second large gear 54 in the first stage of deceleration,
There are two meshing positions of the second small gear 55 and the third large gear 57 in the second speed reduction stage,
There are four meshing positions of the third small gear 58 and the fourth large gear 60 in the third speed reduction stage,
There are four meshing positions of the fourth small gear 61 and the output gear 63 in the fourth speed reduction stage,
There are two fixed portions of the gear shaft 70 that supports the second gear assembly 53 and the fourth gear assembly 59,
There are two bearings for the output shaft 64 that supports the output gear 63 and the third gear assembly 56.
In this way, the first stage and the second stage of deceleration have a high rotational speed but a small transmission torque, so there are two meshing locations, and the third and fourth stages where the transmission speed increases as the deceleration progresses and the rotational speed is slow. 4 places.
Generally, the strength of the speed reducer is determined by the gear strength of the final output stage having a low rotational speed and a large transmission torque. As described above, in the speed reducer of the present invention, there are four meshing positions of the output gear. Therefore, if the meshing tooth width of the fourth small gear and the output gear is 1.5 times, the gear strength of the final output stage is 4 locations × 1.5 times = 6 times. Therefore, a plastic gear having a strength comparable to that of a metal gear can be obtained.
Further, in the planetary gear speed reducer of Patent Document 1, the output shaft of the final output stage has a cantilever support structure. However, in the speed reducer of the present invention, the output shaft of the final output stage, the third gear assembly, and the second gear. The gear shaft that supports the assembly and the fourth gear assembly is fixed at two locations of the front cover and the rear cover.
[0019]
As another embodiment of the present invention, FIG. 8 shows a two-speed reduction gear.
The power of the reduction gear according to the present invention is transmitted from the motor gear 52 coupled to the small motor 51 to the second large gear 92 of the second gear assembly 91. The second small gear 93 integrated with the second large gear 92 is transmitted to the output gear 95 of the output gear assembly 94. Power is transmitted to a load from an output shaft 96 coupled to the output gear 95.
[0020]
FIG. 9 shows a 6-speed reduction gear.
The power of the reduction gear according to the present invention is transmitted from the motor gear 52 coupled to the small motor 51 to the second large gear 102 of the second gear assembly 101. The second small gear 103 integrated with the second large gear 102 is transmitted to the third large gear 105 of the third gear assembly 104. The third small gear 106 integrated with the third large gear 105 is transmitted to the fourth large gear 108 of the fourth gear assembly 107. The fourth small gear 109 integrated with the fourth large gear 108 is transmitted to the fifth large gear 111 of the fifth gear assembly 110. The fifth small gear 112 integrated with the fifth large gear 111 is transmitted to the sixth large gear 114 of the sixth gear assembly 113. This is transmitted from the sixth small gear 115 integrated with the sixth large gear 114 to the output gear 117 of the output gear assembly 116. Power is transmitted to a load from an output shaft 118 coupled to the output gear 117. Therefore, in combination with FIG. 1, a two-stage, four-stage, and six-stage reducer is possible.
[0021]
Further, as another embodiment of the present invention, FIG. 10 shows a case where two gear shafts are equally distributed, and FIG. 11 shows a case where three gear shafts are equally distributed.
In FIG. 10, the gear shaft is arranged at 180 degrees, and the gear meshes at two locations, so a gear tooth number that is a multiple of 2 is selected. In FIG. 11, the gear shaft is arranged at 120 degrees, and the gear meshes at three locations. Therefore, the number of gear teeth that is a multiple of 3 is selected.
In this way, the reduction ratio can be selected by using the odd and even number of teeth. Accordingly, it is possible to select the meshing position of the gear wheel as shown in FIG. 5 as two places, three places, and four places.
[0022]
【The invention's effect】
As in the present invention, a reduction gear for a small motor with a reduction gear using a plastic gear having a strength comparable to that of a metal gear by increasing the gear tooth width of the gears in each stage and increasing the gear tooth width. Can be provided. Furthermore, since the center of the output shaft of the speed reducer coincides with the center of the motor shaft, there is an advantage that the mounting area is reduced.
Therefore, according to the present invention, taking advantage of the fact that "the planetary gear mechanism has a plurality of simultaneous meshing locations and the output shaft is at the center of the speed reducer", "the conventional gear mechanism has only one meshing location. A reduction gear characterized by the fact that the bearing is composed of plastic gears with double-end support structure and multiple simultaneous meshing locations, and the output shaft is located at the center. Can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a reduction gear in a right side view of a small motor with a reduction gear according to the present invention. FIG. 2 is a front view of the small motor with a reduction gear according to the invention. -C2 cross-sectional view [FIG. 5] D1-D2 cross-sectional view [FIG. 6] E1-E2 cross-sectional view [FIG. 7] B1-B2 cross-sectional view [FIG. 8] 2-speed reducer [FIG. [Fig. 10] Gear shaft arranged at 180 degrees [Fig. 11] Gear shaft arranged at 120 degrees [Fig. 12] External view of conventional small motor with reduction gear [Fig. 13] F1-F2 Sectional view [Fig.14] G1-G7 gear development sectional view of conventional small motor with reduction gear [Explanation of symbols]
1, 51 Small motor 2 Reducer 3, 64, 96, 118 Output shaft 20 Motor output shaft 21, 52 Motor gear 22, 53, 91, 101 No. 2 gear assembly 23, 54, 92, 102 No. 2 large gear 24, 55, 93, 103 2nd small gear 25, 56, 104 3rd gear assembly 26, 57, 105 3rd large gear 27, 58, 106 3rd small gear 28, 59, 107 4th gear assembly 29, 60, 108 No. 4 large gear 30, 61, 109 No. 4 small gear 31, 62, 94, 116 Output gear assembly 32, 63, 95, 117 Output gear 33, 80 Front case 34, 81 Rear case 35 Second shaft 36 Third shaft 37 No. 4 shaft 38 Front bearing 39 Rear bearing 65 Anti-load side output shaft 70 Gear shaft 82 Output shaft rear bearing 83 Output shaft front bearing 110 No. 5 gear assembly 111 No. 5 large gear 112 No. 5 small gear 113 6 No. gear assembly 114 No. 6 large gear 115 No. 6 small gear

Claims

A front case having a bearing for supporting the output shaft, a rear case having a bearing for supporting the output shaft on the non-load side of the output shaft, two second gear assemblies, one third gear assembly, and four No. 4 gear assembly, an output gear assembly in which one output gear is coupled, and a small motor reduction gear constituted by four gear shafts, the second large gear of the second gear assembly having two motor gears, Engagement The 2nd small gear of the 2nd gear assembly and the 3rd large gear of the 3rd gear assembly mesh, and the 3rd small gear of the 3rd gear assembly and the 4th large gear of the 4th gear assembly mesh. The number 2 gear assembly of the number gear assembly is meshed with the output gear, and the two number 2 gear assemblies rotate freely on the two gear shafts fixed by the front case and the rear case. The fourth gear assembly rotates freely on the four gear shafts fixed by the front case and the rear case, and one third gear assembly is The center of the output shaft and the motor shaft are characterized by being configured to freely rotate on the output shaft on the non-load side of the output shaft supported by the bearing provided in the front case and the bearing provided in the rear case 4-speed reduction small motor reducer with the same center.

A front case having a bearing for supporting the output shaft, a rear case having a bearing for supporting the output shaft on the non-load side of the output shaft, two second gear assemblies, one third gear assembly, and four In a reduction gear for a small motor composed of a fourth gear assembly, one fifth gear assembly, four sixth gear assemblies, an output gear assembly in which one output gear is coupled, and four gear shafts , The motor gear meshes with the 2nd large gear of the 2nd gear assembly, the 2nd small gear of the 2nd gear assembly and the 3rd large gear of the 3rd gear assembly mesh, 3rd of the 3rd gear assembly The small gear and the 4th large gear of the 4th gear assembly mesh with each other, the 4th small gear of the 4th gear assembly engages with the 5th large gear of the 5th gear assembly, and the 5th small gear of the 5th gear assembly and 6 The 6th large gear of the numbered gear assembly is meshed, and the 6th small gear of the 6th gear assembly is meshed with the output gear. It freely rotates on the two gear shafts fixed by the front case and the rear case, and the four fourth gear assemblies and the four sixth gear assemblies are divided into four pieces fixed by the front case and the rear case. The output on the non-load side of the output shaft that rotates freely on the gear shaft and is supported by a single third gear assembly and one fifth gear assembly with a bearing provided in the front case and a bearing provided in the rear case A 6-speed reduction small motor reducer with the center of the output shaft and the center of the motor shaft, characterized by being configured to freely rotate on the shaft.

A front case having a bearing for supporting the output shaft, a rear case having a bearing for supporting the output shaft on the opposite side of the output shaft, two second gear assemblies, and an output gear assembly in which one output gear is coupled; In a small motor speed reducer constituted by two gear shafts, the motor gear meshes with the second large gear of the second gear assembly, and the second small gear and the output shaft gear of the second gear assembly. The two second gear assemblies are configured so as to rotate freely on the two gear shafts fixed by the front case and the rear case, and the bearings and the rear case provided in the front case are arranged. A two-stage reduction small motor reducer in which the center of the output shaft supported by the provided bearing coincides with the center of the motor shaft.

2. The four-speed reduction small motor reduction gear according to claim 1, wherein the number of the second gear assembly, the fourth gear assembly, and the gear shaft is three.

3. The 6-speed reduction small motor reduction gear according to claim 2, wherein the number of the second gear assembly, the fourth gear assembly, the sixth gear assembly, and the number of gear shafts is three.

The reduction gear for a small motor with two-stage reduction according to claim 3, wherein the number of the second gear assembly and the number of gear shafts are three.

2. A four-speed reduction small motor reduction gear according to claim 1, wherein the number of the second gear assembly, the number of the fourth gear assembly, and the number of the gear shafts are two.

The 6-speed reduction small motor speed reducer according to claim 2, wherein each of the second gear assembly, the fourth gear assembly, the sixth gear assembly, and the gear shaft is two.