JP3738556B2 - Anti-corrosion rolling bearing - Google Patents

Description

【００２７】
なお、絶縁層材料は上記例に何等限定されるものでなく、本発明の範囲内において他の材料を選択するも可能である。また、絶縁層の材料には、ガラス繊維やチタン酸カリウムウィスカなどの強化材など各種充填材や酸化防止剤などの各種添加剤を配合してもよい。その際、充填材や添加剤を加えることによって、誘電率は多少変化することが考えられるので、誘電率が７を超えない範囲内で添加する必要がある。
【００２８】
また絶縁層を、軸受のシールと一体的に形成することも本発明の範囲内である。絶縁層をシールと一体で形成することによって、低コスト化を図ることができる。絶縁層をシールと一体に形成する場合、軸受に内蔵されるグリースの漏れなど、シールとしての機能を有効に発揮する為には、柔軟性を有する熱可塑性エラストマーと合成ゴムがよく、特に表１中の熱可塑性エラストマー、あるいは合成ゴムがよい。また、シールとして安定した形状を維持する為に、金属・合成樹脂の芯材と一体化されていてもよい。さらに、絶縁層は次の（１）〜（３）のいずれかの構成を採用することにより、ハウジングへの挿入性を向上させることも可能である。
（１）外輪外径面上に設けられる絶縁層部分のハウジング挿入側の厚みを薄肉に形成する。（２）緩やかな上り傾斜状のテーパ面を設ける。（３）円周に面取りを施す。また、絶縁層は、次の（１）又は（２）のいずれかの構成を採用することにより、熱膨張による軸方向変化を吸収するものとすることも可能である。
（１）絶縁層上に凸部を設ける。（２）絶縁層上の円周方向に溝を設ける。
【００２９】
【発明の実施形態】
以下、本発明に係る電食防止転がり軸受の実施形態を図面を参照して説明する。尚、図面は玉軸受とした場合の一実施形態を示すが、ころ軸受も本発明の範囲内である。
【００３０】
図１で、Ａは本実施形態の電食防止転がり軸受で、１は内輪、２は外輪、３は転動体、４は保持器、そして５は絶縁層を示す。
【００３１】
絶縁層５は、本実施形態においてはシールを一体的に形成してなるタイプを示す。すなわち絶縁層５は、外輪外径面２ａ上の円周方向全域および側面２ｂの円周方向全域に形成されると共に、該側面２ｂ側に位置する絶縁層部分５ｂからさらに延設されてシール６が一体的に形成されたリング状とされている。
【００３２】
絶縁層５は、合成樹脂、熱可塑性エラストマーあるいは合成ゴムからなり、具体的にはたとえば上記表１に記載したものがあげられ、誘電率が７（１ｋＨｚ）以下のものが好ましい。また、表１記載の材料は一例にすぎず特に限定はされず任意である。
【００３３】
シール６は、絶縁層５と同じ材質である合成樹脂、熱可塑性エラストマーあるいは合成ゴムにて一体的に形成される柔軟部６ａと、金属あるいは合成樹脂からなる芯材６ｂとで構成されている。本実施形態におけるシール６の構造も一実施形態にすぎず、これに何等限定されるものではなく、他の形状あるいは芯材を備えない構造など本発明の範囲内において変更可能なものである。例えば、図１に示すシール６は非接触タイプとしたが、接触タイプであってもよい。また本実施形態では、絶縁層５と一体的なシール６が装着されているのと反対側には、シールド板７が装着されている。
【００３４】
本実施形態では、外輪外径面２ａ上に設けられる絶縁層部分５ａのハウジング挿入側５ｃの厚みを薄肉状に形成しているため、ハウジングへの挿入性が向上されている。そして、本実施形態では、緩やかな上り傾斜状のテーパ面５ｄを設けているため上記挿入性をさらに向上せしめている。
【００３５】
また、本実施形態では外輪２側にのみ絶縁層５を備えたもので説明したが、内輪１側に備えるものとしてもよく、また外輪２と内輪１の双方に備えるものとしてもよく任意である。
【００３６】
本実施形態のように、絶縁層５をシール６と一体とした構造とすると、別体としたものに比べて、シール＋α程度の低コストとすることができるという効果を奏する。
【００３７】
シール６を一体的に形成する絶縁層５の他の実施形態として、図２乃至図６に示す形態があげられる。
【００３８】
図２は、シール６に芯材を備えることなく絶縁層５と同一材料をもって一体的に形成した実施の一形態である。図３は、外輪外径面２ａの全域と両側面２ｂ，２ｂの双方に絶縁層５ａ，５ｂ，５ｂが連続形成されると共に、夫々の側面２ｂ，２ｂに設けられた絶縁層部分５ｂ，５ｂからシール６，６が夫々一体的に延設されている。この構成とすることで、別途シールを設けなくとも両側のシール６，６が同時に備えられることとなる。
【００３９】
図４は、外輪外径面２ａに備えられる絶縁層５上に凸部８…を設けることで、絶縁層５上面を凹凸状に形成するものとした構造で、図５は外輪外径面２ａに備えられる絶縁層５の円周方向に溝９…を、そして図６は外輪外径面２ａに備えられる絶縁層５の軸方向に溝１０…を設けるものとした。このように外径面に凸部８…あるいは溝９…，１０…を設けることにより、ハウジングとの接触面積が小さくなるため、より変形がし易くなり、熱膨張による軸方向変化（収縮）を吸収できる。
【００４０】
図７は、本発明の他の実施形態で、絶縁層がシールと別体に形成されている実施の一形態を示す。図中７は、シール（シールド板）を示す。
【００４１】
本実施形態の電食防止転がり軸受Ｂは、外輪外径面２ａ上の円周方向全域および側面２ｂの円周方向全域にわたって覆うようにリング状に絶縁層１１が形成され、外輪２の外周に圧入されている。
【００４２】
また、本実施形態においては、内輪１側に絶縁層が備えられるものとはしていないが、内輪１の内径面１ａ上の円周方向全域と片方の側面１ｂの円周方向全域を覆うようにリング状の絶縁層１１が圧入されるものとしてもよく、また図示形態とは逆に内輪１側にのみ設けるものとするも本発明の範囲内である。
【００４３】
上記絶縁層１１の角部には、ハウジングへの当該電食防止転がり軸受Ｂの挿入性が良くなるように、円周に面取り１１ａが施されている。
【００４４】
絶縁層１１は、合成樹脂、熱可塑性エラストマーあるいは合成ゴムからなるもので、特に誘電率が７以下（１ｋＨｚ）のものがよく、例えば上記表１に記載する材料で形成され、コスト的には、合成樹脂や熱可塑性エラストマーが射出成形で製造でき好適である。
【００４５】
また、絶縁層１１は薄肉のため、充填材を混入しないと破損等を起しやすいことから、通常はガラス繊維などを含有するものを使用してもよい。
【００４６】
尚、本実施形態の電食防止転がり軸受Ｂには、特にシールを一体的に形成してはいないが、図１に示したようにシールを一体的に形成するものとしてもよく、これに何等限定されず本発明の範囲内において他の形状を選択可能である。また、絶縁層１１が、外輪２の外径面２ａと、一方の側面２ｂにのみ位置するものをもって説明したが、両方の側面２ｂ，２ｂに位置するものとしてもよく、さらに図４乃至図６に示すような凸部８…、溝９，１０…を設けた凹凸状に絶縁層上面を形成することも本実施形態の一形態である。
【００４７】
図８は、上記図７に示した本発明の電食防止転がり軸受Ｂを、２個一対でファン駆動用電動モータ１２内に取り付けた状態を示す断面図である。両電食防止転がり軸受Ｂの外輪２は、それぞれモータハウジング１３の両端部に形成した保持段部１４或いは保持凹部１５の内側に、絶縁層（リング状絶縁部材）１１を介して嵌め込まれている。尚、１３ａはハウジング本体、１３ｂはハウジング前蓋、１３ｃはハウジング後蓋である。また、１６はモータ回転軸、１７はロータ、１８はステータである。
【００４８】
そして、絶縁層１１の大鰐部１１ｂを、上記保持段部１４或いは保持凹部１５の奥面に対向させた状態で固定されている。前記大鰐部１１ｂは、軸受外輪２の一側面（端面）２ｂと保持段部１４或いは保持凹部１５の奥面とに挟持されて、これら両面が当接するのを阻止する。
【００４９】
また、各絶縁層（リング状絶縁部材）１１の円筒部１１ｃは、外輪２の外径面（外周面）２ａと、保持段部１４或いは保持凹部１５の内周面との間に挟持されて、これら両周面同士が当接するのを阻止する。なお、外輪２の他方の側面（端面）２ｂは空気中にさらされた状態になっており、特に絶縁層１１で被う必要がない。
【００５０】
このように、本発明の電食防止転がり軸受をモータ中に組み込むことによって、インバータからステータ１８に印可される高周波電流に基づいてモータ回転軸１６に軸電圧が惹起されても、この回転軸１６とモータハウジング１３との間に電流が流れることを最低限に抑えることができる。
【００５１】
すなわち、上記回転軸１６を支持する電食防止転がり軸受Ｂの外輪２と、これらの外輪２を保持している部材であるモータハウジング１３との取付け個所が絶縁されているので、上記回転軸１６の電位がモータハウジング１３の電位より高くなっても、これら外輪２を組み込んでなる各電食防止転がり軸Ｂに流れる電流は最低限に抑えられる。従って、これら各電食防止転がり軸受Ｂに電食が発生する事がない。
【００５２】
【実施例】
次に、本実施形態の軸受における電食試験を所定条件の下に行い、その試験結果を表２に示す。
電食試験
試験軸受：６２０２（ＮＳ７グリース封入）
アキシャル荷重：３ｋｇｆ
印加電流：１２ｍＡ／２個
回転時間：５００ｈｒ，１０００ｈｒ，１５００ｈｒ（各１）
供試体：（１）実施例１：図１記載の転がり玉軸受
受絶縁層厚さ：0.5ｍｍ
材質：シリコンゴム ＳＮＮＳ（東洋シール（株）製）
誘電率：3.7（１ｋＨｚ）
（２）実施例２：図７記載の転がり玉軸受
絶縁層厚さ：0.5ｍｍ
材質：４０ｗｔ％ＧＦ入りＰＰＳ樹脂
フォートロン（商標）１１４０Ａ４（ポリプラスチックス（株）製）
誘電率：4.6（１ｋＨｚ）
（３）実施例３：図７記載の転がり玉軸受
絶縁層厚さ：0.5ｍｍ
材質：ポリエステルエラストマハイトレル（商標）３５４８Ｗ（東レ・デュポン（株）製）
誘電率：6.2（１ｋＨｚ）
（４）比較例１：図１記載の転がり玉軸受
絶縁層厚さ：0.5ｍｍ
材質：ニトリルゴム ＴＮＮ（東洋シール（株）製）
誘電率：11.5（１ｋＨｚ）
（５）比較例２：図７記載の転がり玉軸受
絶縁層厚さ：0.5ｍｍ
材質：フッ化ビニリデン樹脂ネオフロン（商標）ＶＤＦＶＰ−８００（ダイキン工業（株）製）
誘電率：7.7（１ｋＨｚ）
（６）比較例３：両側Ｚシールド板，絶縁層なし
試験装置：図９，図１０（概念図）
【００５３】
【表２】

【００５４】
表２に示すように、図７に示す絶縁被膜（絶縁層１１）を有する転がり軸受を図８に示すファン駆動用電動モータ１２に組込み、電食防止効果を確認した結果、絶縁被膜誘電率が７以下とすることで軸受に流れる電流値を4.0mmＡ以下と出来、1500ｈｒ回転後においても電食を防止することができる。尚、内輪１の内径面１ａ上の円周方向全域と片方の側面１ｂの円周方向全域を覆うようリング状の絶縁層１１を設けても（外輪外径面２ａ上の円周方向全域および側面２ｂの円周方向全域に覆うようにリング状に絶縁層１１が形成されたものと組合せるのも、又単独に用いることも）同様の効果がある。
【００５５】
【発明の効果】
本発明の電食防止転がり軸受によれば、本発明の電食防止転がり軸受によれば、外輪の外径面と内輪の内径面のいずれか一方又は双方及びこれら外輪、内輪の少なくとも一方の側面に合成樹脂、熱可塑性エラストマー、合成ゴムの何れかからなる絶縁層を形成したことから、この軸受をインバータ駆動されるファンモータに用いると、従来のように電気的導通性を有する特殊なグリースを使用したり塵埃が発生し易い電気的ブラシを設置することなく、軸受内外輪間を流れる電流を最低限に抑えることができ、その結果、内外輪軌道面あるいは転動体転動面の電食を防止できるという効果を奏する。
【００５６】
また、外径面に備えられる絶縁層の材質を柔軟性を有する合成樹脂、熱可塑性エラストマーあるいは合成ゴムを用いると、上記効果に加えて、更に軸受のハウジングへの挿入が容易で且つハウジング内で突っ張ってクリープ防止機能を発揮するという効果を得られる。
【図面の簡単な説明】
【図１】本発明転がり軸受の一実施形態を示す縦断側面図。
【図２】他の実施形態の一例を示す縦断側面図。
【図３】他の実施形態の一例を示す縦断側面図。
【図４】他の実施形態の一例を示す縦断側面図。
【図５】他の実施形態の一例を示す縦断側面図。
【図６】他の実施形態の一例を示す縦断側面図。
【図７】他の実施形態の一例を示す縦断側面図。
【図８】本発明の電食防止転がり軸受を組込んだ状態のモータの実施形態を示す断面図。
【図９】試験装置の概略図。
【図１０】試験装置の概略図。
【符号の説明】
１：内輪
２：外輪
２ａ：外径面
２ｂ：側面
３：転動体
４：保持器
５，１１：絶縁層
６：シール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a rolling bearing used for a fan motor whose speed is controlled by an inverter and capable of preventing electric corrosion.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a rolling bearing (hereinafter also simply referred to as a bearing) incorporated in a fan motor (hereinafter also simply referred to as a motor) is attached with an outer ring mounted on a housing and an inner ring fitted on a rotor shaft of the motor with a clearance fit or an interference fit. Needless to say, it is an interference fit, but in the case of a clearance fit, the bearings are pressed by pressing the side surfaces of the inner ring or outer ring through a spacer to increase the rigidity of the bearing and prevent vibrations. Therefore, the outer ring and the bracket, and the inner ring and the rotor shaft are electrically connected to each other.
[0003]
On the other hand, fan motors are increasingly controlled in speed via an inverter that can vary the rotational speed in order to control the air volume. In that case, motor noise due to switching can be reduced by setting the carrier frequency of the inverter high, and it has become possible to set the carrier frequency high by improving the performance of semiconductor elements and improving circuit technology. For this reason, the carrier frequency of inverters has been set higher.
[0004]
Along with this, the shaft voltage generated in the motor driven by the inverter increases, and a potential difference is generated between the rotor shaft and the housing and thus between the inner and outer rings of the bearing, so that current flows through the rolling elements in the bearing, and as a result, There is an increasing possibility of electrolytic corrosion on the raceway surface of the ring or the rolling surface of the rolling element.
[0005]
Conventionally, when a fan motor driven by an inverter has a risk of electric corrosion, the following measures are taken.
(1) When an electric brush can be installed, the electric brush is brought into contact with the rotor shaft to keep the rotor shaft and the housing at the same potential, thereby preventing current from flowing through the inner and outer rings of the bearing.
(2) Or, by enclosing grease that imparts electrical conductivity to the bearing, the inner and outer rings of the bearing are kept at an equipotential to prevent current from flowing.
(3) Alternatively, grease with high base oil viscosity is sealed in the bearing to increase the thickness of the oil film formed between the bearing outer ring and the rolling element and between the bearing inner ring and the rolling element. Insulate.
[0006]
[Problems to be solved by the invention]
However, each of these conventional electric corrosion prevention measures has the following problems.
[0007]
Regarding the installation of the electric brush, one end of the rotor shaft of the motor is housed in the housing so that there is no space for installing the electric brush, and the other end of the rotor shaft has a fan formed of an insulating material such as synthetic resin. Since it is mounted, it is often difficult to bring the electric brush into contact with the rotor shaft, and as a practical matter, it is often impossible to install the electric brush on the fan motor.
[0008]
Further, even if an electric brush can be installed, there is a problem that the abrasion powder of the brush is discharged from the fan motor and released as dust in the air. For example, if a fan motor with an electric brush is used in a clean room, it becomes a fatal defect and cannot be put to practical use.
With regard to the sealing of the grease imparted with electrical conductivity, the grease contains a good electrical conductor such as carbon particles, so the rotational noise of the bearing has to be larger than that of normal grease. In addition, the use of such expensive special grease has the disadvantage of increasing the cost of the bearing.
[0010]
Regarding the sealing of grease with a high base oil viscosity, assuming that the temperature rise is caused by an increase in bearing torque due to the viscosity of the grease, and that the current passing between the inner and outer rings of the bearing is an alternating current with a high frequency, There is a problem that current may be conducted in a gap of the oil film thickness. In addition, the oil film formation state fluctuates due to the deterioration of the enclosed grease over time or the entry of foreign matter into the grease, so there is a possibility that electrical conduction and insulation will occur alternately and electric corrosion may occur. It cannot be.
[0011]
The present invention has been made in view of such problems of the prior art, and the object of the present invention is to replace the outer diameter surface of the outer ring with a means such as installation of an electric brush or special grease filling. An anti-corrosion rolling bearing that minimizes the value of the current flowing in the bearing by forming an insulating layer so as to cover one or both of the inner diameter surfaces of the inner ring and at least one side surface of the raceway ring. The purpose is to provide.
[0012]
[Means for Solving the Problems]
The technical means made by the first invention in order to achieve the above-mentioned objects are an outer ring, an inner ring, a rolling element disposed between the outer ring and the inner ring, and an insulating layer fitted from one side to the outer side of the outer ring. The insulating layer is a ring shape in which a portion that accommodates the outer ring outer diameter surface of the bearing and a portion that forms a seal on the side surface of the bearing are integrally formed, and at least a portion that forms the seal is a core material the a, and said as the material of the insulating layer, polyester elastomer dielectric constant from 3 to 6.2 at 1 kHz, polyamide elastomer dielectric constant 3.5-5 at 1 kHz, the dielectric constant is 1 kHz This is an electrodeposition-preventing rolling bearing characterized in that at least one of silicon rubber of 3 to 5 and fluorine rubber of 2 to 3 is selected at a dielectric constant of 1 kHz .
[0013]
Further technical means second invention have none, in the first invention, as the material of the insulating layer, a polyamide-based elastomer dielectric constant 3.5-5 at 1 kHz, a dielectric constant 3 at 1 kHz This is a rolling bearing characterized in that any one of the five silicon rubbers is selected .
[0014]
Further, the technical means made by the third invention is that, in the first invention, the insulating layer is formed such that the portion on the housing insertion side of the outer ring outer diameter surface is thinly formed, or a gently upwardly inclined shape is formed. In other words, the electric corrosion-preventing rolling bearing is characterized in that the insertion property into the housing is improved by adopting a configuration in which the taper surface is provided or the circumference is chamfered.
[0015]
Further, the technical means made by the fourth invention is that, in the second invention, the insulating layer is formed such that the portion on the housing insertion side of the outer ring outer diameter surface is formed thin, or a gently upwardly inclined shape is formed. In other words, the electric corrosion-preventing rolling bearing is characterized in that the insertion property into the housing is improved by adopting a configuration in which the taper surface is provided or the circumference is chamfered.
[0016]
Further, the technical means made by the fifth invention is that, in the first invention, the core material of the insulating layer is a metal-corrosion-preventing rolling bearing characterized by being a metal.
[0017]
Further, the technical means made by the sixth invention is that in the second invention, the core material of the insulating layer is a metal-corrosion-preventing rolling bearing characterized in that it is a metal.
[0018]
Further, the technical means made by the seventh invention is the electric corrosion prevention rolling bearing according to the first invention, wherein the rolling bearing is a rolling bearing for a fan motor whose speed is controlled by an inverter. That is.
[0019]
Further, the technical means made by the eighth invention is the electric corrosion prevention rolling bearing according to the second invention, wherein the rolling bearing is a rolling bearing for a fan motor whose speed is controlled by an inverter. That is.
[0020]
Therefore, even if a shaft voltage is generated in the motor driven by the inverter, there is almost no potential difference between the inner and outer rings of the bearing. Therefore, the current value flowing between the inner and outer rings of the bearing is suppressed to a minimum, and electrolytic corrosion of the raceway surfaces of the inner and outer rings or the rolling surfaces of the rolling elements can be prevented.
[0021]
In addition, it is possible to absorb the axial expansion and contraction that occurs during operation by utilizing the elasticity of the insulating layer rubber or thermoplastic elastomer, and it is also possible to prevent the occurrence of creep by using rubber or thermoplastic elastomer having a large linear expansion. .
[0022]
The material of the insulating layer is selected in consideration of oil resistance and heat resistance. As rubber, acrylic rubber, acrylonitrile butadiene rubber (NBR), fluorine rubber, hydrogenated acrylonitrile butadiene rubber (H-NBR), thermoplastic elastomer Are selected from polyester elastomer, polyamide elastomer, and synthetic resin from polyphenylene sulfide (PPS), polyamide (PA), polybutylene terephthalate (PBT), and the like.
[0023]
Furthermore, considering the usage environment of the bearing in addition to the dielectric constant, the material must have a certain level of heat resistance and oil resistance and must be low in cost, and can be used as an insulating layer (synthetic resin, heat The dielectric constant of the plastic elastomer or the synthetic rubber is 7 or less, more preferably 5 or less at a frequency of 1 kHz.
[0024]
When the dielectric constant exceeds 7, the value of the current flowing between the inner and outer rings of the bearing becomes high and electric corrosion occurs. Also, if the current passing between the inner and outer rings of the bearing is an alternating current with a high frequency, the flowing current value will be small, but current will flow, resulting in galvanic corrosion, and the noise level due to bearing rotation. Depending on the material, there will be a large increase.
[0025]
Specifically, materials shown in Table 1 below are suitable. In particular, those having a low dielectric constant are optimal in terms of insulation effect, and the lower the better, the better.
[0026]
[Table 1]

[0027]
The insulating layer material is not limited to the above examples, and other materials can be selected within the scope of the present invention. Moreover, you may mix | blend various additives, such as various fillers and antioxidants, such as reinforcements, such as glass fiber and potassium titanate whisker, with the material of an insulating layer. At this time, it is conceivable that the dielectric constant slightly changes by adding a filler or an additive. Therefore, it is necessary to add the dielectric constant within a range where the dielectric constant does not exceed 7.
[0028]
It is also within the scope of the present invention to form the insulating layer integrally with the bearing seal. By forming the insulating layer integrally with the seal, the cost can be reduced. When the insulating layer is formed integrally with the seal, a flexible thermoplastic elastomer and a synthetic rubber are preferable in order to effectively exert the function as the seal, such as leakage of grease incorporated in the bearing. Among them, a thermoplastic elastomer or synthetic rubber is preferable. In order to maintain a stable shape as a seal, it may be integrated with a metal / synthetic resin core material. Furthermore, the insulating layer can improve the insertion property into the housing by adopting any one of the following configurations (1) to (3).
(1) The thickness on the housing insertion side of the insulating layer portion provided on the outer ring outer diameter surface is formed thin. (2) A gently upwardly inclined tapered surface is provided. (3) Chamfer the circumference. In addition, the insulating layer can also absorb changes in the axial direction due to thermal expansion by adopting the following configuration (1) or (2).
(1) Protrusions are provided on the insulating layer. (2) Grooves are provided in the circumferential direction on the insulating layer.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an electric corrosion prevention rolling bearing according to the present invention will be described with reference to the drawings. The drawing shows an embodiment in the case of a ball bearing, but a roller bearing is also within the scope of the present invention.
[0030]
In FIG. 1, A is an electric corrosion prevention rolling bearing of this embodiment, 1 is an inner ring, 2 is an outer ring, 3 is a rolling element, 4 is a cage, and 5 is an insulating layer.
[0031]
In this embodiment, the insulating layer 5 is a type in which a seal is integrally formed. That is, the insulating layer 5 is formed in the entire circumferential direction on the outer ring outer diameter surface 2a and in the entire circumferential direction of the side surface 2b, and is further extended from the insulating layer portion 5b located on the side surface 2b side to seal 6 Is a ring formed integrally.
[0032]
The insulating layer 5 is made of a synthetic resin, a thermoplastic elastomer, or a synthetic rubber. Specific examples include those listed in Table 1 above, and a dielectric constant of 7 (1 kHz) or less is preferable. The materials listed in Table 1 are merely examples, and are not particularly limited and are arbitrary.
[0033]
The seal 6 includes a flexible portion 6a integrally formed of a synthetic resin, a thermoplastic elastomer, or a synthetic rubber, which is the same material as the insulating layer 5, and a core material 6b made of a metal or a synthetic resin. The structure of the seal 6 in the present embodiment is also only one embodiment, and is not limited to this, and can be modified within the scope of the present invention, such as a structure having no other shape or core material. For example, the seal 6 shown in FIG. 1 is a non-contact type, but may be a contact type. In the present embodiment, a shield plate 7 is mounted on the opposite side of the seal 6 integrated with the insulating layer 5.
[0034]
In this embodiment, since the thickness of the housing insertion side 5c of the insulating layer portion 5a provided on the outer ring outer diameter surface 2a is formed thin, insertion into the housing is improved. In the present embodiment, the insertion property is further improved because the tapered surface 5d having a gentle upward slope is provided.
[0035]
In the present embodiment, the insulating layer 5 is provided only on the outer ring 2 side. However, the insulating layer 5 may be provided on the inner ring 1 side, and may be provided on both the outer ring 2 and the inner ring 1. .
[0036]
When the insulating layer 5 is integrated with the seal 6 as in the present embodiment, the cost of the seal + α can be reduced as compared with a separate structure.
[0037]
Other embodiments of the insulating layer 5 that integrally form the seal 6 include the forms shown in FIGS. 2 to 6.
[0038]
FIG. 2 shows an embodiment in which the seal 6 is integrally formed of the same material as the insulating layer 5 without providing a core material. FIG. 3 shows that insulating layers 5a, 5b, 5b are continuously formed on the entire outer ring outer diameter surface 2a and both side surfaces 2b, 2b, and insulating layer portions 5b, 5b provided on the respective side surfaces 2b, 2b. The seals 6 and 6 are integrally extended. With this configuration, the seals 6 and 6 on both sides are provided at the same time without providing a separate seal.
[0039]
FIG. 4 shows a structure in which the upper surface of the insulating layer 5 is formed in an uneven shape by providing convex portions 8 on the insulating layer 5 provided on the outer ring outer diameter surface 2a. FIG. 5 shows the outer ring outer diameter surface 2a. Grooves 9 are provided in the circumferential direction of the insulating layer 5 provided in FIG. 6 and FIG. 6 is provided with grooves 10 in the axial direction of the insulating layer 5 provided in the outer ring outer diameter surface 2a. By providing the convex portions 8... Or the grooves 9... 10 on the outer diameter surface in this way, the contact area with the housing is reduced, so that it becomes easier to deform and the axial change (shrinkage) due to thermal expansion. Can be absorbed.
[0040]
FIG. 7 shows another embodiment of the present invention in which the insulating layer is formed separately from the seal. In the figure, 7 indicates a seal (shield plate).
[0041]
In the electrolytic corrosion-preventing rolling bearing B of the present embodiment, an insulating layer 11 is formed in a ring shape so as to cover the entire circumferential direction on the outer ring outer diameter surface 2 a and the entire circumferential direction of the side surface 2 b, and the outer ring 2 has an outer periphery. It is press-fitted.
[0042]
In the present embodiment, an insulating layer is not provided on the inner ring 1 side, but covers the entire circumferential direction on the inner diameter surface 1a of the inner ring 1 and the entire circumferential direction of one side surface 1b. A ring-shaped insulating layer 11 may be press-fitted into the inner ring 1 and provided only on the inner ring 1 side, contrary to the illustrated embodiment, within the scope of the present invention.
[0043]
The corner portion of the insulating layer 11 is chamfered 11a on the circumference so that the electric corrosion prevention rolling bearing B can be inserted into the housing.
[0044]
The insulating layer 11 is made of a synthetic resin, a thermoplastic elastomer or a synthetic rubber, and particularly preferably has a dielectric constant of 7 or less (1 kHz). For example, the insulating layer 11 is made of the material shown in Table 1 above, and in terms of cost, Synthetic resins and thermoplastic elastomers are suitable because they can be manufactured by injection molding.
[0045]
In addition, since the insulating layer 11 is thin, it can easily be damaged unless a filler is mixed therein. Therefore, a material containing glass fiber or the like may be used.
[0046]
In addition, although the seal | sticker is not specifically formed in the electric corrosion prevention rolling bearing B of this embodiment in particular, it is good also as what forms a seal | sticker integrally as shown in FIG. Without limitation, other shapes can be selected within the scope of the present invention. In addition, the insulating layer 11 is described as being located only on the outer diameter surface 2a of the outer ring 2 and one of the side surfaces 2b. However, the insulating layer 11 may be located on both side surfaces 2b and 2b, and FIGS. It is also an embodiment of the present embodiment that the upper surface of the insulating layer is formed in a concavo-convex shape provided with convex portions 8..., Grooves 9, 10.
[0047]
FIG. 8 is a cross-sectional view showing a state in which the electric corrosion prevention rolling bearing B of the present invention shown in FIG. The outer ring 2 of the electric corrosion-preventing rolling bearing B is fitted into the holding step 14 or holding recess 15 formed at both ends of the motor housing 13 via an insulating layer (ring-shaped insulating member) 11. . Reference numeral 13a denotes a housing body, 13b denotes a housing front lid, and 13c denotes a housing rear lid. Reference numeral 16 denotes a motor rotation shaft, 17 denotes a rotor, and 18 denotes a stator.
[0048]
And the large collar part 11b of the insulating layer 11 is being fixed in the state which was made to oppose the back surface of the said holding | maintenance step part 14 or the holding | maintenance recessed part 15. FIG. The large flange portion 11b is sandwiched between one side surface (end surface) 2b of the bearing outer ring 2 and the rear surface of the holding step portion 14 or the holding recess portion 15, and prevents these both surfaces from coming into contact with each other.
[0049]
The cylindrical portion 11 c of each insulating layer (ring-shaped insulating member) 11 is sandwiched between the outer diameter surface (outer peripheral surface) 2 a of the outer ring 2 and the inner peripheral surface of the holding step portion 14 or the holding recess 15. The two peripheral surfaces are prevented from coming into contact with each other. The other side surface (end surface) 2b of the outer ring 2 is exposed to the air and does not need to be covered with the insulating layer 11 in particular.
[0050]
Thus, by incorporating the electric corrosion prevention rolling bearing of the present invention in the motor, even if an axial voltage is induced in the motor rotating shaft 16 based on the high frequency current applied from the inverter to the stator 18, the rotating shaft 16. Current between the motor housing 13 and the motor housing 13 can be minimized.
[0051]
That is, the outer shaft 2 of the electric corrosion-preventing rolling bearing B that supports the rotating shaft 16 and the motor housing 13 that is a member that holds the outer ring 2 are insulated from each other. Is higher than the potential of the motor housing 13, the current flowing through each of the electric corrosion prevention rolling shafts B incorporating these outer rings 2 is kept to a minimum. Therefore, no electrolytic corrosion occurs in each of these electrolytic corrosion preventing rolling bearings B.
[0052]
【Example】
Next, an electrolytic corrosion test on the bearing of this embodiment was performed under predetermined conditions, and the test results are shown in Table 2.
Electric corrosion test test bearing: 6202 (with NS7 grease)
Axial load: 3kgf
Applied current: 12 mA / 2 pieces Rotation time: 500 hr, 1000 hr, 1500 hr (each 1)
Specimen: (1) Example 1: Rolling ball bearing receiving insulating layer thickness shown in FIG. 1 Thickness: 0.5 mm
Material: Silicon rubber SNNS (manufactured by Toyo Seal Co., Ltd.)
Dielectric constant: 3.7 (1 kHz)
(2) Example 2: Rolling ball bearing insulating layer thickness shown in FIG. 7 Thickness: 0.5 mm
Material: 40 wt% GF-containing PPS resin Fortron (trademark) 1140A4 (manufactured by Polyplastics Co., Ltd.)
Dielectric constant: 4.6 (1 kHz)
(3) Example 3: Rolling ball bearing insulating layer thickness shown in FIG. 7: 0.5 mm
Material: Polyester Elastomer Hytrel (trademark) 3548W (manufactured by Toray DuPont)
Dielectric constant: 6.2 (1 kHz)
(4) Comparative Example 1: Rolling ball bearing insulating layer thickness shown in FIG. 1: 0.5 mm
Material: Nitrile rubber TNN (Toyo Seal Co., Ltd.)
Dielectric constant: 11.5 (1 kHz)
(5) Comparative Example 2: Rolling ball bearing insulating layer thickness shown in FIG. 7: 0.5 mm
Material: Vinylidene fluoride resin NEOFLON (trademark) VDFVP-800 (manufactured by Daikin Industries, Ltd.)
Dielectric constant: 7.7 (1 kHz)
(6) Comparative Example 3: Both-side Z shield plate, test device without insulation layer: FIGS. 9 and 10 (conceptual diagram)
[0053]
[Table 2]

[0054]
As shown in Table 2, the rolling bearing having the insulating film (insulating layer 11) shown in FIG. 7 was incorporated in the electric motor 12 for driving the fan shown in FIG. By setting it to 7 or less, the value of the current flowing through the bearing can be 4.0 mmA or less, and electrolytic corrosion can be prevented even after 1500 hours of rotation. Even if the ring-shaped insulating layer 11 is provided so as to cover the entire circumferential direction on the inner diameter surface 1a of the inner ring 1 and the entire circumferential direction on one side surface 1b (the entire circumferential direction on the outer ring outer diameter surface 2a and The same effect can be obtained by combining with the ring-shaped insulating layer 11 so as to cover the entire circumferential direction of the side surface 2b or by using it alone.
[0055]
【The invention's effect】
According to the electric corrosion-preventing rolling bearing of the present invention, according to the electric corrosion-preventing rolling bearing of the present invention, either or both of the outer diameter surface of the outer ring and the inner diameter surface of the inner ring, and at least one side surface of the outer ring and the inner ring. Since an insulating layer made of synthetic resin, thermoplastic elastomer, or synthetic rubber is formed on this bearing, when this bearing is used for a fan motor driven by an inverter, a special grease having electrical conductivity as in the past is used. The current flowing between the inner and outer rings of the bearing can be kept to a minimum without using electric brushes that tend to generate dust, and as a result, the electric corrosion of the inner and outer ring raceways or rolling element rolling surfaces can be reduced. There is an effect that it can be prevented.
[0056]
In addition to the above effects, the use of a flexible synthetic resin, thermoplastic elastomer or synthetic rubber as the material of the insulating layer provided on the outer diameter surface makes it easier to insert the bearing into the housing and It is possible to obtain an effect of exerting an anti-creep function by stretching.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing an embodiment of a rolling bearing of the present invention.
FIG. 2 is a longitudinal side view showing an example of another embodiment.
FIG. 3 is a longitudinal side view showing an example of another embodiment.
FIG. 4 is a longitudinal side view showing an example of another embodiment.
FIG. 5 is a longitudinal side view showing an example of another embodiment.
FIG. 6 is a longitudinal side view showing an example of another embodiment.
FIG. 7 is a longitudinal side view showing an example of another embodiment.
FIG. 8 is a cross-sectional view showing an embodiment of a motor in which the electric corrosion prevention rolling bearing of the present invention is incorporated.
FIG. 9 is a schematic view of a test apparatus.
FIG. 10 is a schematic view of a test apparatus.
[Explanation of symbols]
1: Inner ring 2: Outer ring 2a: Outer diameter surface 2b: Side surface 3: Rolling element 4: Cage 5, 11: Insulating layer 6: Seal

Claims (8)

Outer ring and inner ring,
A rolling element disposed between the outer ring and the inner ring;
Consists of an insulating layer fitted from one side to the outside of the outer ring,
The insulating layer includes a portion that accommodates the outer ring outer diameter surface of the bearing;
In the ring shape in which the part that forms the seal on the side of the bearing is configured integrally,
At least a portion forming the seal has a core material,
And,
Wherein the material of the insulating layer, polyester elastomer dielectric constant from 3 to 6.2 at 1 kHz, polyamide elastomer dielectric constant 3.5-5 at 1 kHz, 1 kHz at 3-5 silicon dielectric constant An electric corrosion-preventing rolling bearing characterized in that any one of rubber and fluororubber having a dielectric constant of 1 to 3 at a frequency of 1 kHz is selected . As the material of the insulating layer, to claim 1, characterized in that the dielectric constant of polyamide elastomer of 3.5-5 at 1 kHz, any of silicone rubber dielectric 3-5 at 1 kHz is selected The described electric corrosion-proof rolling bearing. The insulating layer has a configuration in which the thickness on the housing insertion side of the portion that accommodates the outer surface of the outer ring is formed thin, a tapered surface having a gently upward slope is provided, or the circumference is chamfered. 2. The electrolytic corrosion-preventing rolling bearing according to claim 1, wherein the electric corrosion prevention rolling bearing is improved by being adopted. The insulating layer has a configuration in which the thickness on the housing insertion side of the portion that accommodates the outer surface of the outer ring is formed thin, a tapered surface having a gently upward slope is provided, or the circumference is chamfered. The electrolytic corrosion-preventing rolling bearing according to claim 2, wherein the electric corrosion prevention rolling bearing is improved by adopting it. 2. The electrolytic corrosion-preventing rolling bearing according to claim 1, wherein the core material of the insulating layer is a metal. 3. The electrolytic corrosion-preventing rolling bearing according to claim 2, wherein the core material of the insulating layer is a metal. The rolling corrosion prevention bearing according to claim 1, wherein the rolling bearing is a rolling bearing for a fan motor whose speed is controlled by an inverter. The rolling corrosion bearing according to claim 2, wherein the rolling bearing is a rolling bearing for a fan motor whose speed is controlled by an inverter.

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