JPH10322965A - Motor - Google Patents
MotorInfo
- Publication number
- JPH10322965A JPH10322965A JP12375097A JP12375097A JPH10322965A JP H10322965 A JPH10322965 A JP H10322965A JP 12375097 A JP12375097 A JP 12375097A JP 12375097 A JP12375097 A JP 12375097A JP H10322965 A JPH10322965 A JP H10322965A
- Authority
- JP
- Japan
- Prior art keywords
- bearings
- bearing
- roller bearing
- low
- filled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Motor Or Generator Frames (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、電動機に係り、特
にベアリングの電食を防止するに好適な電動機に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor, and more particularly to an electric motor suitable for preventing electrolytic corrosion of a bearing.
【0002】[0002]
【従来の技術】図2に電動機の概略構造図を示す。図2
に示すように電動機は、ハウジング1の内周側に支承さ
れた固定子2とエンドブラケット3(3a、3b)に支
持された軸受4(4a、4b)により支えられた回転軸
5を介して前記固定子2の内周側に支承された回転子6
を有し、ボルト等を用いて該フレーム1と該エンドブラ
ケット3a及び3bを嵌合させることにより構成され
る。2. Description of the Related Art FIG. 2 is a schematic structural view of a motor. FIG.
As shown in FIG. 1, the electric motor is driven by a stator 2 supported on the inner peripheral side of the housing 1 and a rotary shaft 5 supported by bearings 4 (4a, 4b) supported by end brackets 3 (3a, 3b). A rotor 6 supported on the inner peripheral side of the stator 2
And the frame 1 is fitted to the end brackets 3a and 3b using bolts or the like.
【0003】以上のような電動機において、印加される
電源に不平衡が生じたり、固定子2と回転子6間のギャ
ップの不均一や、固定子2に施された各相の巻線の不平
衡により電位差が生じ、図2の矢印Bの如く軸電流が流
れるが、この電流により軸受4a、4bにて電食が発生
することがある。この電食とは、絶縁された軸受内にお
いて電位差が生じ、やがて放電を繰り返し、その放電エ
ネルギにより軸受が損傷することを指す。In the motor described above, imbalance occurs in the applied power, the gap between the stator 2 and the rotor 6 becomes uneven, and the winding of each phase applied to the stator 2 becomes unbalanced. A potential difference occurs due to the equilibrium, and an axial current flows as shown by an arrow B in FIG. 2, but this current may cause electrolytic corrosion in the bearings 4a and 4b. This electrolytic corrosion indicates that a potential difference is generated in the insulated bearing, the discharge is repeated, and the bearing is damaged by the discharge energy.
【0004】これに対し、図3に示す如くエンドブラケ
ット3と軸受4の間に絶縁シート7を入れ絶縁し、軸受
4に流れる軸電流を低減することも考えられる。On the other hand, as shown in FIG. 3, it is conceivable to insert an insulating sheet 7 between the end bracket 3 and the bearing 4 to insulate the bearing and reduce the axial current flowing through the bearing 4.
【0005】[0005]
【発明が解決しようとする課題】しかし、図3の軸電流
を絶縁する構造では、構造が複雑となり、コスト高とな
る。また、インバータ等のひずみ波電源駆動時のよう
に、電源のスイッチング毎の一瞬におこる電圧不平衡に
より発生する非常に高い周波数(数MHz)の軸電流に
対しては、エンドブラケット3と軸受4間の静電容量を
大きくとる必要があるため、エンドブラケット3と軸受
4間の距離を大きく取り、絶縁シート7を厚くしなけれ
ばならないが、軸受支持部の剛性が低下するため、絶縁
シート7として必要な厚みを確保することが困難であっ
た。However, the structure for insulating the axial current shown in FIG. 3 requires a complicated structure and a high cost. Also, when a distorted wave power supply such as an inverter is driven, a very high frequency (several MHz) shaft current generated due to a voltage imbalance that occurs instantaneously at every power supply switching is used. Since it is necessary to increase the capacitance between the end bracket 3 and the bearing 4, the distance between the end bracket 3 and the bearing 4 needs to be large and the insulating sheet 7 has to be thickened. It was difficult to secure the required thickness.
【0006】以上の問題点を解消するために、本発明は
容易に軸受にて発生する電食を低減できる電動機を提供
することを目的としている。[0006] In order to solve the above problems, an object of the present invention is to provide an electric motor that can easily reduce electrolytic corrosion generated in a bearing.
【0007】[0007]
【課題を解決するための手段】上記目的は、粘度の低い
グリースを封入したころ軸受を少なくとも1つ備えるこ
とにより達成される。The above object is achieved by providing at least one roller bearing in which low-viscosity grease is sealed.
【0008】[0008]
【発明の実施の形態】一般に転がり軸受(玉軸受ところ
軸受に大別される)は軌道輪(内輪と外輪)、転動体
(玉又はころ)および保持器から構成され、封入された
グリースにより油膜が形成され軌道輪と転動体は絶縁さ
れている。同一の軸受では油膜が厚いほど油膜絶縁破壊
電圧が高く絶縁能力に長けている(図4参照)が、膜厚
は粘度や接触面周速等により変化することや、実際に軸
電流により軸受にて電食が発生し、異音、焼き付き等の
トラブルが報告されていることから、完全な絶縁は困難
である。そこで、図3に挙げた絶縁構造が考えられる
が、インバータ等のひずみ波電源駆動時に発生する軸電
流に対しては有効な手法ではない。そこで完全な絶縁で
はなく、転動体を玉からころに変更し、転動体と軌道輪
を点接触から線接触とすることにより、単位面積あたり
の放電エネルギを激減させ電食を低減する。くわえて、
粘度の低いグリースを軸受に封入し油膜を薄くし、油膜
絶縁破壊電圧を下げ放電エネルギを低く抑えることによ
り、電食のさらなる低減が可能となる。粘度の低いグリ
ースを軸受に封入した場合、膜圧が薄くなり膜圧強度は
低下するが、転動体と軌道輪を点接触から線接触とする
ことで面圧は低くなるため、膜圧強度の低下は問題な
い。さらに、主要寸法が同一の玉軸受ところ軸受を比較
すると、ころ軸受の方が負荷容量が大きくまた長寿命で
あるため、転動体を玉からころに変更することで負荷を
制限したり、寿命が短くなることなく、粘度の低いグリ
ースを封入したころ軸受を採用でき、電食の低減が可能
となる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Rolling bearings (which are roughly classified into ball bearings and bearings) are generally composed of races (inner and outer rings), rolling elements (balls or rollers) and a cage. Are formed and the race and the rolling element are insulated. In the same bearing, the thicker the oil film, the higher the oil film dielectric breakdown voltage and the higher the insulation capacity (see FIG. 4). However, the film thickness varies depending on the viscosity, the peripheral speed of the contact surface, and the like. Since electrical erosion has occurred and troubles such as abnormal noise and burn-in have been reported, complete insulation is difficult. Therefore, the insulating structure shown in FIG. 3 is conceivable, but this is not an effective method for a shaft current generated when a distorted wave power supply such as an inverter is driven. Therefore, instead of complete insulation, the rolling element is changed from a ball to a roller, and the rolling element and the bearing ring are changed from point contact to line contact, thereby drastically reducing discharge energy per unit area and reducing electrolytic corrosion. In addition,
By enclosing grease with low viscosity in the bearing to thin the oil film, lower the oil film dielectric breakdown voltage and suppress the discharge energy, it is possible to further reduce electrolytic corrosion. When grease with low viscosity is sealed in the bearing, the film pressure is reduced and the film pressure strength is reduced, but the surface pressure is reduced by changing the rolling element and the raceway from point contact to line contact, so the film pressure strength is reduced. The drop is fine. Furthermore, when comparing ball bearings with the same major dimensions and bearings, roller bearings have a larger load capacity and a longer life, so changing the rolling element from a ball to a roller limits the load and reduces the life. Without shortening, a roller bearing in which grease having a low viscosity is sealed can be employed, thereby reducing electric corrosion.
【0009】以下、本発明による電動機について、実施
例により詳細に説明する。Hereinafter, the motor according to the present invention will be described in detail with reference to embodiments.
【0010】図1は本発明の一実施例による電動機にお
いて、反負荷側軸受4bに比べ粘度の低いグリースを封
入したころ軸受4aを負荷側に採用したものである。な
お、図1は負荷側に粘度の低いグリースを封入したころ
軸受4aを配置しているが、反負荷側に配置しても問題
ない。また、軸受を3個以上使用する場合、少なくとも
1つ他軸受に比べ粘度の低いグリースを封入したころ軸
受を備えていれば、どこに配置してもよい。ここで、こ
の実施例による電動機においてハウジング1、固定子
2、エンドブラケット3(3a、3b)回転軸5、回転
子6、軸受4bは図2で説明した電動機と特に変りは無
い。FIG. 1 shows a motor according to an embodiment of the present invention, in which a roller bearing 4a in which grease having a lower viscosity than that of the non-load-side bearing 4b is sealed is used on the load side. In FIG. 1, the roller bearing 4a containing low-viscosity grease is disposed on the load side, but there is no problem if the roller bearing 4a is disposed on the non-load side. When three or more bearings are used, they may be arranged anywhere as long as at least one roller bearing in which grease having a lower viscosity than other bearings is provided is provided. Here, in the electric motor according to this embodiment, the housing 1, the stator 2, the end bracket 3 (3a, 3b), the rotating shaft 5, the rotor 6, and the bearing 4b are not particularly different from the electric motor described with reference to FIG.
【0011】負荷側軸受4aにおいて、ころ軸受の採用
により単位面積あたりの放電エネルギが低いこと、油膜
絶縁破壊電圧を低下させることにより低電圧による放電
が繰り返されるが、低電圧のため放電エネルギそのもの
を低く抑えられることから電食が低減できる。In the load-side bearing 4a, the discharge energy per unit area is low due to the use of roller bearings, and the discharge at a low voltage is repeated by lowering the oil film dielectric breakdown voltage. Electric corrosion can be reduced because it is kept low.
【0012】また、負荷側軸受4aに粘度の低いグリー
スを封入し油膜を薄くすることにより、負荷側軸受4a
は反負荷側軸受4bよりインピーダンスが低く、図1の
矢印Aの如く軸電流は流れ、反負荷側軸受4bの保護が
可能となる。Also, by filling low-viscosity grease into the load-side bearing 4a and thinning the oil film, the load-side bearing 4a
Has a lower impedance than the non-load-side bearing 4b, an axial current flows as shown by the arrow A in FIG. 1, and the protection of the non-load-side bearing 4b becomes possible.
【0013】[0013]
【発明の効果】本発明によれば、電動機において、粘度
の低いグリースを封入したころ軸受を少なくとも1つ備
えることにより、軸電流により軸受にて発生する電食を
低減することが可能となり、信頼性の高い電動機を提供
することができる。According to the present invention, an electric motor is provided with at least one roller bearing in which low-viscosity grease is sealed, so that it is possible to reduce electrolytic corrosion generated in the bearing due to a shaft current. It is possible to provide a high-performance electric motor.
【図1】本発明による電動機の一実施例を説明するため
の部分断面による側面図FIG. 1 is a partial cross-sectional side view for explaining an embodiment of an electric motor according to the present invention.
【図2】従来の軸絶縁構造を示す電動機の部分断面によ
る側面図FIG. 2 is a side view of a partial cross section of a motor showing a conventional shaft insulating structure.
【図3】従来の軸絶縁構造を示す電動機の部分図FIG. 3 is a partial view of a motor showing a conventional shaft insulation structure.
【図4】グリース粘度と油膜絶縁破壊電圧の関係を示す
図FIG. 4 is a diagram showing a relationship between grease viscosity and oil film dielectric breakdown voltage.
1…ハウジング、 2…固定子、 3a…負荷側エンド
ブラケット、 3b…反負荷側エンドブラケット、 4
a…負荷側軸受、 4b…反負荷側軸受、 5…回転
軸、 6…回転子、 7…絶縁シート。DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Stator, 3a ... Load side end bracket, 3b ... Non-load side end bracket, 4
a: Load side bearing, 4b: Anti-load side bearing, 5: Rotating shaft, 6: Rotor, 7: Insulating sheet.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 鈴木 利文 千葉県習志野市東習志野七丁目1番1号株 式会社日立製作所産業機器事業部内 (72)発明者 関根 昭裕 千葉県習志野市東習志野七丁目1番1号株 式会社日立製作所産業機器事業部内 (72)発明者 山中 桂介 千葉県習志野市東習志野七丁目1番1号日 立京葉エンジニアリング株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshifumi Suzuki 7-1-1, Higashi-Narashino, Narashino-shi, Chiba Industrial Equipment Division, Hitachi, Ltd. (72) Inventor Akihiro Sekine 7-1-1, Higashi-Narashino, Narashino-shi, Chiba (1) Inside the Industrial Equipment Division of Hitachi, Ltd. (72) Inventor Keisuke Yamanaka 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Inside Tachiyo Keiyo Engineering Co., Ltd.
Claims (1)
相交流巻線が施された固定子と、回転軸に保持された回
転子と、回転軸を保持する複数の軸受と、これら軸受を
保持するエンドブラケットを有する電動機において、粘
度の低いグリースを封入したころ軸受を少なくとも1つ
備えることを特徴とする電動機。1. A housing, a stator provided with a polyphase AC winding held by the housing, a rotor held by a rotating shaft, a plurality of bearings holding the rotating shaft, and holding these bearings. A motor having at least one roller bearing filled with low-viscosity grease in a motor having an end bracket.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12375097A JPH10322965A (en) | 1997-05-14 | 1997-05-14 | Motor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12375097A JPH10322965A (en) | 1997-05-14 | 1997-05-14 | Motor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH10322965A true JPH10322965A (en) | 1998-12-04 |
Family
ID=14868396
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP12375097A Pending JPH10322965A (en) | 1997-05-14 | 1997-05-14 | Motor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH10322965A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7667357B2 (en) | 2006-05-30 | 2010-02-23 | Nidec Shibaura Corporation | Motor having shaft members |
EP2378645A1 (en) * | 2009-04-28 | 2011-10-19 | Panasonic Corporation | Electric motor and electric equipment with same |
JP2017078540A (en) * | 2015-10-20 | 2017-04-27 | 三菱重工業株式会社 | Indoor unit, air conditioner including the same and method of assembling indoor unit |
-
1997
- 1997-05-14 JP JP12375097A patent/JPH10322965A/en active Pending
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7667357B2 (en) | 2006-05-30 | 2010-02-23 | Nidec Shibaura Corporation | Motor having shaft members |
EP2378645A1 (en) * | 2009-04-28 | 2011-10-19 | Panasonic Corporation | Electric motor and electric equipment with same |
CN102369652A (en) * | 2009-04-28 | 2012-03-07 | 松下电器产业株式会社 | Electric motor and electric equipment with same |
EP2378645A4 (en) * | 2009-04-28 | 2012-08-29 | Panasonic Corp | Electric motor and electric equipment with same |
US8975796B2 (en) | 2009-04-28 | 2015-03-10 | Panasonic Intellectual Property Management Co., Ltd. | Electric motor and electric equipment with same |
JP2017078540A (en) * | 2015-10-20 | 2017-04-27 | 三菱重工業株式会社 | Indoor unit, air conditioner including the same and method of assembling indoor unit |
WO2017068861A1 (en) * | 2015-10-20 | 2017-04-27 | 三菱重工業株式会社 | Indoor unit, air conditioner provided with indoor unit, and method for assembling indoor unit |
CN107850321A (en) * | 2015-10-20 | 2018-03-27 | 三菱重工制冷空调***株式会社 | The assemble method of indoor set, the air conditioner for possessing the indoor set and indoor set |
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