JP7488725B2 - Insulated Rolling Bearing - Google Patents

Insulated Rolling Bearing Download PDF

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JP7488725B2
JP7488725B2 JP2020142802A JP2020142802A JP7488725B2 JP 7488725 B2 JP7488725 B2 JP 7488725B2 JP 2020142802 A JP2020142802 A JP 2020142802A JP 2020142802 A JP2020142802 A JP 2020142802A JP 7488725 B2 JP7488725 B2 JP 7488725B2
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insulating
resin
inner ring
rolling bearing
peripheral surface
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JP2022038349A (en
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章央 松本
裕 田中
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NTN Corp
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NTN Corp
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Priority to CN202180050675.5A priority patent/CN115885113A/en
Priority to PCT/JP2021/031148 priority patent/WO2022045190A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
    • F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
    • F16C35/07—Fixing them on the shaft or housing with interposition of an element

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)
  • Mounting Of Bearings Or Others (AREA)

Description

本発明は、絶縁転がり軸受に関する。 The present invention relates to an insulating rolling bearing.

例えば、電動モータの回転軸や冷媒圧縮機の回転軸などのように電流が流れる可能性のある回転軸を絶縁して支持する絶縁転がり軸受が知られている。絶縁転がり軸受を用いることで、転がり軸受の内輪、外輪の両軌道面と転動体の転動面に電食が発生することを防止できる。 For example, insulating rolling bearings are known that insulate and support rotating shafts through which current may flow, such as the rotating shafts of electric motors and refrigerant compressors. The use of insulating rolling bearings can prevent electrolytic corrosion from occurring on the raceway surfaces of both the inner and outer rings of the rolling bearing and on the rolling surfaces of the rolling elements.

例えば、特許文献１記載の冷媒圧縮機では、クランク軸における駆動部よりも反圧縮機構部側の副軸部を回転支持する副軸受とクランク軸との間に樹脂材料で構成された樹脂製スリーブが設けられている。これにより、導電性グリースが充填された転がり軸受を使用することなく、安価な構造で、電食による軸受損傷を抑制して冷媒圧縮機の信頼性向上を図っている。 For example, in the refrigerant compressor described in Patent Document 1, a resin sleeve made of a resin material is provided between the crankshaft and a secondary bearing that supports the rotation of the secondary shaft portion of the crankshaft that is on the opposite side of the compression mechanism portion from the drive portion. This allows for an inexpensive structure without using rolling bearings filled with conductive grease, suppressing bearing damage caused by electrolytic corrosion and improving the reliability of the refrigerant compressor.

特開２０１８－４０２６１号公報JP 2018-40261 A

上記特許文献１記載の冷媒圧縮機では、樹脂製スリーブが、圧入などの手段で内輪の内周面に嵌め込まれている。しかしながら、加熱と冷却が繰り返される実機での使用条件では、樹脂製スリーブがクランク軸に抱き着くことや、樹脂製スリーブが内輪から抜けることが懸念される。また、同様の樹脂製スリーブを、外輪の外周面に嵌め込んで絶縁性を図ることが考えられるが、樹脂製スリーブが外輪に抱き着くことや、樹脂製スリーブがハウジングから抜けることが懸念される。 In the refrigerant compressor described in Patent Document 1, a plastic sleeve is fitted to the inner peripheral surface of the inner ring by means of press fitting or the like. However, under operating conditions in an actual machine where heating and cooling are repeated, there is concern that the plastic sleeve may cling to the crankshaft or come off the inner ring. It is also possible to fit a similar plastic sleeve onto the outer peripheral surface of the outer ring to improve insulation, but there is concern that the plastic sleeve may cling to the outer ring or come off the housing.

本発明は上記事情に鑑みてなされたものであり、電食を防止するとともに、軸などへの抱き着きや、内輪などからの脱落を防止できる絶縁転がり軸受を提供することを目的とする。 The present invention was made in consideration of the above circumstances, and aims to provide an insulated rolling bearing that can prevent electrolytic corrosion and can prevent the bearing from clinging to a shaft or falling off an inner ring.

本発明の絶縁転がり軸受は、鋼材からなる内輪および外輪と、この内・外輪間に介在する複数の転動体と、上記内輪の内周面または上記外輪の外周面に嵌合された略円筒状の絶縁ブッシュとを備えた絶縁転がり軸受であって、上記絶縁ブッシュは、外径側に樹脂組成物からなる絶縁部と、内径側に金属部とを有することを特徴とする。 The insulated rolling bearing of the present invention is an insulated rolling bearing comprising an inner ring and an outer ring made of steel, a plurality of rolling elements interposed between the inner and outer rings, and a substantially cylindrical insulating bush fitted to the inner peripheral surface of the inner ring or the outer peripheral surface of the outer ring, the insulating bush having an insulating part made of a resin composition on the outer diameter side and a metal part on the inner diameter side.

上記絶縁部と上記金属部が別体で構成されていることを特徴とする。また、上記金属部は、周方向の一部に合い口が形成された割ブッシュであり、上記絶縁部は、上記割ブッシュの合い口を外径側から覆う円筒部材であることを特徴とする。 The insulating part and the metal part are configured as separate bodies. The metal part is a split bushing with a joint formed in a portion of the circumferential direction, and the insulating part is a cylindrical member that covers the joint of the split bushing from the outer diameter side.

上記絶縁部の外周面は、軸方向の一方側から他方側に向かって拡径するテーパ形状であることを特徴とする。 The outer peripheral surface of the insulating part is characterized by a tapered shape that expands in diameter from one side to the other side in the axial direction.

上記絶縁部の上記樹脂組成物のベース樹脂が、ポリフェニレンサルファイド（ＰＰＳ）樹脂、ポリエーテルケトン（ＰＥＫ）系樹脂、テトラフルオロエチレン－パーフルオロアルキルビニルエーテル共重合体（ＰＦＡ）樹脂、テトラフルオロエチレン－ヘキサフルオロプロピレン共重合体（ＦＥＰ）樹脂、またはテトラフルオロエチレン－エチレン共重合体（ＥＴＦＥ）樹脂であることを特徴とする。 The base resin of the resin composition of the insulating part is polyphenylene sulfide (PPS) resin, polyether ketone (PEK) resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, or tetrafluoroethylene-ethylene copolymer (ETFE) resin.

上記金属部が機械構造用炭素鋼またはステンレス鋼であることを特徴とする。 The metal part is made of mechanical structural carbon steel or stainless steel.

本発明の絶縁転がり軸受は、内輪の内周面または外輪の外周面に嵌合された略円筒状の絶縁ブッシュを備え、該絶縁ブッシュは、外径側に樹脂組成物からなる絶縁部と、内径側に金属部とを有するので、例えば、内輪内径に嵌合する場合、内輪の内周面に接触する側に樹脂製の絶縁部が配置され、軸に接触する側に金属部が配置されることで、軸と内輪が金属接触することがなく電食を防止できる。また、樹脂製の絶縁部と軸とが接触することがないので、絶縁部の軸への抱き着きも防止できる。 The insulating rolling bearing of the present invention comprises a substantially cylindrical insulating bush fitted to the inner circumferential surface of the inner ring or the outer circumferential surface of the outer ring, and the insulating bush has an insulating part made of a resin composition on the outer diameter side and a metal part on the inner diameter side. For example, when fitted to the inner diameter of the inner ring, the resin insulating part is arranged on the side that contacts the inner circumferential surface of the inner ring, and the metal part is arranged on the side that contacts the shaft, so that there is no metallic contact between the shaft and the inner ring and electrolytic corrosion can be prevented. In addition, because there is no contact between the resin insulating part and the shaft, the insulating part can also be prevented from clinging to the shaft.

また、内輪は軸受鋼などの鋼材からなり、樹脂材料に対して線膨張係数が小さい。そのため、使用環境範囲の高温側では絶縁部は、内輪の内周面に沿う方向となる。一方、使用環境範囲の低温側では、絶縁部は縮小するおそれがあるが、内径側の金属部が内側から絶縁部を支えることで樹脂の収縮が抑えられる。これにより、加熱と冷却が繰り返される条件においても、絶縁ブッシュが内輪から脱落することを防止できる。 The inner ring is made of steel such as bearing steel, and has a smaller linear expansion coefficient than the resin material. Therefore, at the high temperature end of the operating environment range, the insulating portion is oriented along the inner peripheral surface of the inner ring. On the other hand, at the low temperature end of the operating environment range, there is a risk that the insulating portion will shrink, but the metal portion on the inner diameter side supports the insulating portion from the inside, suppressing the shrinkage of the resin. This makes it possible to prevent the insulating bush from falling off the inner ring, even under conditions where heating and cooling are repeated.

また、外輪外径に絶縁ブッシュを嵌合する場合にも、樹脂製の絶縁部と外輪とが接触することがないので、絶縁部の外輪への抱き着きを防止しつつ、電食を防止できる。また、使用環境範囲の高温側では絶縁部は、ハウジングの内周面に沿う方向となる。一方、使用環境範囲の低温側では、絶縁部は縮小するおそれがあるが、内径側の金属部が内側から絶縁部を支えることで樹脂の収縮が抑えられる。これにより、加熱と冷却が繰り返される条件においても、絶縁ブッシュがハウジングから脱落することを防止できる。 In addition, even when the insulating bushing is fitted to the outer diameter of the outer ring, there is no contact between the resin insulating part and the outer ring, so it is possible to prevent the insulating part from sticking to the outer ring and prevent electrolytic corrosion. Furthermore, on the high temperature side of the operating environment range, the insulating part is oriented along the inner circumferential surface of the housing. On the other hand, on the low temperature side of the operating environment range, there is a risk that the insulating part will shrink, but the metal part on the inner diameter side supports the insulating part from the inside, suppressing the shrinkage of the resin. This makes it possible to prevent the insulating bushing from falling off the housing, even under conditions where heating and cooling are repeated.

絶縁部と金属部が別体で構成されるので、一体に構成する場合に比べて、絶縁部と金属部の形状の自由度を向上できる。さらに、金属部は、周方向の一部に合い口が形成された割ブッシュであり、絶縁部は、金属部の合い口を外径側から覆う円環部材であるので、合い口を形成することで金属部に径方向に拡がるばね力を持たせることができ、絶縁部の縮小が好適に抑えられる。また、合い口を絶縁部で覆うことで電食を確実に防止できる。 Because the insulating part and the metal part are constructed separately, the degree of freedom in the shapes of the insulating part and the metal part can be improved compared to when they are constructed as one unit. Furthermore, the metal part is a split bushing with a joint formed in part of the circumferential direction, and the insulating part is a circular member that covers the joint of the metal part from the outer diameter side. Therefore, by forming the joint, it is possible to give the metal part a spring force that expands in the radial direction, and shrinkage of the insulating part is suitably suppressed. Furthermore, covering the joint with the insulating part reliably prevents electrolytic corrosion.

絶縁部の外周面は、軸方向の一方側から他方側に向かって拡径するテーパ状であるので、例えば内輪と絶縁部との嵌め合いの管理が容易になり、ひいては低コスト化を図ることができる。 The outer peripheral surface of the insulating part is tapered, expanding in diameter from one side in the axial direction to the other, which makes it easier to manage the fit between the inner ring and the insulating part, for example, and ultimately reduces costs.

絶縁部の樹脂組成物のベース樹脂がＰＰＳ樹脂、ＰＥＫ系樹脂、ＰＦＡ樹脂、ＦＥＰ樹脂、またはＥＴＦＥ樹脂であるので、耐熱性や耐薬品性に優れる。 The base resin of the resin composition of the insulating part is PPS resin, PEK resin, PFA resin, FEP resin, or ETFE resin, so it has excellent heat resistance and chemical resistance.

本発明の絶縁転がり軸受の拡大断面図である。FIG. 2 is an enlarged cross-sectional view of an insulating rolling bearing according to the present invention. 図１の絶縁ブッシュの分解斜視図などである。FIG. 2 is an exploded perspective view of the insulating bush of FIG. 1 . 絶縁ブッシュの他の形態を示す分解斜視図などである。11A to 11C are exploded perspective views showing other embodiments of the insulating bush. 絶縁ブッシュの他の形態を示す分解斜視図などである。11A to 11C are exploded perspective views showing other embodiments of the insulating bush. 比較例１～２の試験部材の軸方向断面図である。FIG. 2 is an axial cross-sectional view of the test members of Comparative Examples 1 and 2. 抜去力試験の概略を示す図である。FIG. 1 is a diagram showing an outline of a removal force test. 通電試験の概略を示す図である。FIG. 1 is a diagram showing an outline of an electrical test. 抜去力試験後の比較例１の写真である。1 is a photograph of Comparative Example 1 after a removal force test. 実施例および比較例の製造コストを比較したグラフである。1 is a graph comparing the manufacturing costs of an example and a comparative example. セラミックス溶射の形成箇所の製造コストを比較したグラフである。1 is a graph comparing the manufacturing costs of ceramic spray-coated areas.

本発明の絶縁転がり軸受の一形態について、図１を用いて説明する。図１に示すように、絶縁転がり軸受１は、軌道輪である内輪２および外輪３と、この内・外輪間に介在する複数の玉（転動体）４とを有する軸受本体部と、内輪２の内周面に嵌合された絶縁ブッシュ１０とを備える。玉４は、保持器５によって一定間隔に整列して保持されている。玉４周囲の軸受空間にはグリース７が充填されており、シール部材６によって軸受空間が密封されている。内輪２と外輪３と玉４は、鋼材で形成されている。なお、鋼材としては、転がり軸受などに使用されるＳＵＪ２などの軸受鋼、浸炭鋼、機械構造用炭素鋼、冷間圧延鋼、または熱間圧延鋼などが挙げられる。 One embodiment of the insulated rolling bearing of the present invention will be described with reference to FIG. 1. As shown in FIG. 1, the insulated rolling bearing 1 comprises a bearing body having an inner ring 2 and an outer ring 3 as raceways, a plurality of balls (rolling elements) 4 interposed between the inner and outer rings, and an insulating bush 10 fitted to the inner peripheral surface of the inner ring 2. The balls 4 are aligned and held at regular intervals by a cage 5. The bearing space around the balls 4 is filled with grease 7, and the bearing space is sealed by a seal member 6. The inner ring 2, the outer ring 3, and the balls 4 are made of steel. Examples of steel include bearing steels such as SUJ2 used for rolling bearings, carburized steel, carbon steel for machine construction, cold-rolled steel, and hot-rolled steel.

図１において、絶縁ブッシュ１０は、略円筒状であり、外径側に樹脂組成物からなる絶縁部８と、内径側に金属部９とを有する。絶縁転がり軸受１において、軸受本体部と絶縁ブッシュ１０は圧入嵌合により一体化されており、接着剤などにより接着されていない。絶縁転がり軸受１の軸孔にシャフトＳが挿入されることで、シャフトＳ、絶縁ブッシュ１０、および内輪２は一体となる。図１のように、絶縁部８が、シャフトＳと内輪２との間に介在することで、軸電流がシャフトＳを介して軸受本体部に流れることを遮断できる。 In FIG. 1, the insulating bush 10 is substantially cylindrical, and has an insulating portion 8 made of a resin composition on the outer diameter side, and a metal portion 9 on the inner diameter side. In the insulated rolling bearing 1, the bearing body and the insulating bush 10 are integrated by press-fitting, and are not bonded with adhesive or the like. When the shaft S is inserted into the axial hole of the insulated rolling bearing 1, the shaft S, the insulating bush 10, and the inner ring 2 become integrated. As shown in FIG. 1, the insulating portion 8 is interposed between the shaft S and the inner ring 2, so that the axial current can be prevented from flowing through the shaft S to the bearing body.

図２を参照して、絶縁ブッシュ１０について詳細に説明する。図２（ａ）は、内輪および絶縁ブッシュの分解斜視図を示す。図２（ａ）において、絶縁部８と金属部９は別体で構成されている。絶縁部８は所定の肉厚を有する円筒部材であり、後述の樹脂組成物の成形体である。金属部９は、周方向の一部に合い口９ａが形成された割ブッシュである。図２（ａ）において、合い口９ａは金属部９の軸方向に沿って形成されている。なお、合い口９ａは、軸方向に対して所定角度傾斜しつつ、軸方向の一端部から他端部にかけて形成されていてもよい。所定角度は、例えば１°～３０°であり、好ましくは１°～１０°である。 The insulating bush 10 will be described in detail with reference to FIG. 2. FIG. 2(a) shows an exploded perspective view of the inner ring and the insulating bush. In FIG. 2(a), the insulating part 8 and the metal part 9 are separate bodies. The insulating part 8 is a cylindrical member having a predetermined thickness, and is a molded body of a resin composition described below. The metal part 9 is a split bush with a joint 9a formed in a part of the circumferential direction. In FIG. 2(a), the joint 9a is formed along the axial direction of the metal part 9. The joint 9a may be formed from one end to the other end in the axial direction while being inclined at a predetermined angle with respect to the axial direction. The predetermined angle is, for example, 1° to 30°, and preferably 1° to 10°.

絶縁転がり軸受の組み立て順は、まず、内輪２の内周面２ａに、締め代を持たせて円筒部材の絶縁部８を嵌め込む。その後、絶縁部８の内周面８ａに、合い口９ａを狭めて金属部９を弾性変形させながら嵌め込むことで、絶縁ブッシュが得られる。 The assembly procedure for an insulating rolling bearing is as follows: first, the insulating part 8 of the cylindrical member is fitted onto the inner circumferential surface 2a of the inner ring 2 with a certain amount of interference. Then, the metal part 9 is fitted onto the inner circumferential surface 8a of the insulating part 8 by narrowing the gap 9a while elastically deforming it, to obtain an insulating bushing.

図２（ｂ）には、絶縁ブッシュが嵌め込まれた状態の径方向断面図を示す。金属部９は、絶縁部８を内輪２の内周面２ａに押し付ける方向に付勢するばね性を有しており、そのばね力によって絶縁部８の内周面８ａに固定されている。金属部９の合い口９ａは、径方向外側に拡がるばね力を適度に発揮させつつ、シャフトを安定して支持できるように形成されることが好ましい。例えば、合い口９ａの中心位置を基準とした±θの範囲内に、離間した２つの端部が収まるように形成される。この範囲は、金属部９において、合い口９ａの中心位置（各端部端面間の円周方向での中心位置）を円周位置で０°とし、これを基準に中心角で±θとなる範囲をいう。この±θの範囲は、±１０°の範囲が好ましく、±５°の範囲が好ましい。 Figure 2 (b) shows a radial cross-sectional view of the insulating bush fitted in place. The metal part 9 has a spring property that urges the insulating part 8 in a direction pressing it against the inner peripheral surface 2a of the inner ring 2, and is fixed to the inner peripheral surface 8a of the insulating part 8 by the spring force. The joint 9a of the metal part 9 is preferably formed so that it can stably support the shaft while exerting an appropriate spring force that spreads radially outward. For example, it is formed so that the two separated ends are within a range of ±θ based on the center position of the joint 9a. This range refers to the range of the central angle ±θ based on the center position of the joint 9a (the center position in the circumferential direction between the end faces of each end) of the metal part 9 being 0° at the circumferential position. This range of ±θ is preferably a range of ±10°, and more preferably a range of ±5°.

図２（ｂ）に示すように、絶縁部８が、金属部９の合い口９ａを外径側から覆うことで絶縁性が確保されている。使用温度環境によって、絶縁部８が膨張または収縮する可能性があるが、金属部９は径方向外側に拡がるばね性を有しており、そのばね力によって絶縁部８が内輪２の内周面２ａに押し付けられるので、絶縁部８の膨張や収縮が抑えられ、絶縁転がり軸受の内径の寸法安定性を維持できる。その結果、温度環境にかかわらず、シャフトを安定して支持できる。 As shown in FIG. 2(b), the insulating part 8 covers the joint 9a of the metal part 9 from the outer diameter side, ensuring insulation. Depending on the temperature environment in use, the insulating part 8 may expand or contract, but the metal part 9 has a springiness that expands radially outward, and this spring force presses the insulating part 8 against the inner circumferential surface 2a of the inner ring 2, suppressing expansion or contraction of the insulating part 8 and maintaining dimensional stability of the inner diameter of the insulated rolling bearing. As a result, the shaft can be stably supported regardless of the temperature environment.

金属部の材質は強度の面から溶製金属が好ましく、鉄系の溶製金属がより好ましい。鉄系としては、一般構造用炭素鋼（ＳＳ４００など）、機械構造用炭素鋼（Ｓ４５Ｃなど）、ステンレス鋼（ＳＵＳ３０３、ＳＵＳ３１６など）などが使用できる。また、これらの鉄系に、亜鉛、ニッケル、銅などのめっきを施してもよい。金属部の肉厚は特に限定されず、例えば０．５ｍｍ～５ｍｍであり、より好ましくは１ｍｍ～３ｍｍである。図２の割ブッシュは、所定の肉厚の金属板を曲げ加工することなどで得られる。 The material of the metal part is preferably a melt-cast metal from the viewpoint of strength, and more preferably an iron-based melt-cast metal. As the iron-based material, general structural carbon steel (SS400, etc.), mechanical structural carbon steel (S45C, etc.), stainless steel (SUS303, SUS316, etc.), etc. can be used. Furthermore, these iron-based materials may be plated with zinc, nickel, copper, etc. The thickness of the metal part is not particularly limited, and is, for example, 0.5 mm to 5 mm, and more preferably 1 mm to 3 mm. The split bush in FIG. 2 can be obtained by bending a metal plate of a specified thickness.

また、絶縁部の肉厚は特に限定されず、例えば０．５ｍｍ～５ｍｍであり、より好ましくは１ｍｍ～３ｍｍである。絶縁部の肉厚と金属部の肉厚に関して、どちらがより厚くても、もしくは同等程度の厚さでもよい。 The thickness of the insulating part is not particularly limited, and is, for example, 0.5 mm to 5 mm, and more preferably 1 mm to 3 mm. Regarding the thickness of the insulating part and the thickness of the metal part, either may be thicker, or they may be about the same thickness.

絶縁部に用いる樹脂組成物のベース樹脂としては、例えば、ＰＥＫ系樹脂、ポリアセタール（ＰＯＭ）樹脂、ＰＰＳ樹脂、射出成形可能な熱可塑性ポリイミド樹脂、ポリアミドイミド（ＰＡＩ）樹脂、ポリアミド（ＰＡ）樹脂、射出成形可能なフッ素樹脂などが挙げられる。なお、これらの樹脂は単独で使用しても、２種類以上混合したポリマーアロイとしてもよい。これらの樹脂の中でも、耐薬品性と耐熱性に優れることから、ＰＰＳ樹脂、ＰＥＫ系樹脂、ＰＦＡ樹脂、ＦＥＰ樹脂、ＥＴＦＥ樹脂が好ましい。なお、ＰＥＫ系樹脂としては、ポリエーテルエーテルケトン（ＰＥＥＫ）樹脂、ポリエーテルケトン（ＰＥＫ）樹脂、ポリエーテルケトンエーテルケトンケトン（ＰＥＫＥＫＫ）樹脂などが挙げられる。 Examples of base resins for the resin composition used in the insulating part include PEK resins, polyacetal (POM) resins, PPS resins, injection moldable thermoplastic polyimide resins, polyamideimide (PAI) resins, polyamide (PA) resins, and injection moldable fluororesins. These resins may be used alone or in combination to form a polymer alloy. Among these resins, PPS resins, PEK resins, PFA resins, FEP resins, and ETFE resins are preferred because of their excellent chemical resistance and heat resistance. Examples of PEK resins include polyetheretherketone (PEEK) resins, polyetherketone (PEK) resins, and polyetherketoneetherketoneketone (PEKEKK) resins.

また、必要に応じて上記ベース樹脂に添加剤を適宜配合できる。添加剤としては、耐クリープ性を向上できることから、例えばガラス繊維、アラミド繊維、チタン酸カリウムウィスカ、酸化チタンウィスカなどの非導電性の補強材などを配合できる。 Additives can be added to the base resin as needed. Additives that can improve creep resistance include non-conductive reinforcing materials such as glass fiber, aramid fiber, potassium titanate whiskers, and titanium oxide whiskers.

絶縁部に用いる樹脂組成物の線膨張係数は１×１０－５／℃～１０×１０－５／℃であることが好ましく、１×１０－５／℃～５×１０－５／℃であることがより好ましい。また、金属部の材質の線膨張係数との関係は特に限定されず、例えば、絶縁部の材質の線膨張係数を金属部の材質の線膨張係数よりも大きくすることが好ましい。 The linear expansion coefficient of the resin composition used for the insulating part is preferably 1×10 −5 /° C. to 10×10 −5 /° C., and more preferably 1×10 −5 /° C. to 5×10 −5 /° C. The relationship with the linear expansion coefficient of the material of the metal part is not particularly limited, and for example, it is preferable that the linear expansion coefficient of the material of the insulating part is larger than the linear expansion coefficient of the material of the metal part.

絶縁部の成形方法は、特に限定されず、圧縮成形、押出成形、射出成形などの方法を採用できる。射出成形の場合、諸原材料を溶融混練して成形用ペレットとし、これを用いて射出成形法により所定形状に成形する。 There are no particular limitations on the method for molding the insulating part, and methods such as compression molding, extrusion molding, and injection molding can be used. In the case of injection molding, the various raw materials are melted and kneaded to form molding pellets, which are then used to mold into the desired shape by injection molding.

本発明に係る絶縁ブッシュの他の形態を図３に示す。図３に示す絶縁ブッシュ１３は、図２の絶縁ブッシュ１０と比べて、絶縁部の構成が異なっている。図３（ａ）は、内輪および絶縁ブッシュの分解斜視図であり、図３（ｂ）は絶縁ブッシュの軸方向断面図である。 Another embodiment of the insulating bush according to the present invention is shown in FIG. 3. The insulating bush 13 shown in FIG. 3 has a different insulating part configuration compared to the insulating bush 10 in FIG. 2. FIG. 3(a) is an exploded perspective view of the inner ring and the insulating bush, and FIG. 3(b) is an axial cross-sectional view of the insulating bush.

図３（ａ）において、絶縁部１１と金属部１２は別体で構成されている。金属部１２は、周方向の一部に離間した合い口１２ａが形成された割ブッシュであり、図２（ａ）の金属部９と同様の構成である。一方、絶縁部１１は、図３（ｂ）に示すように、内周面１１ａが軸方向と平行な円筒面であり、外周面１１ｂが軸方向の一方側から他方側に向かって拡径するテーパ面である。絶縁部１１の肉厚は、軸方向の一方側から他方側に向かって厚くなっており、軸方向の各端部が肉厚の最薄部と最厚部になる。最薄部と最厚部の肉厚差は、例えば０．５ｍｍ～２ｍｍである。なお、この形態において、絶縁部１１の肉厚の方が金属部１２の肉厚よりも厚いこと、つまり絶縁部１１の最薄部の肉厚が金属部１２の肉厚よりも厚いことが好ましい。 3(a), the insulating part 11 and the metal part 12 are configured as separate bodies. The metal part 12 is a split bushing in which a gap 12a is formed in a part of the circumferential direction, and has the same configuration as the metal part 9 in FIG. 2(a). On the other hand, as shown in FIG. 3(b), the insulating part 11 has an inner peripheral surface 11a that is a cylindrical surface parallel to the axial direction, and an outer peripheral surface 11b that is a tapered surface that expands in diameter from one side to the other side in the axial direction. The thickness of the insulating part 11 increases from one side to the other side in the axial direction, and each end in the axial direction becomes the thinnest part and the thickest part of the thickness. The difference in thickness between the thinnest part and the thickest part is, for example, 0.5 mm to 2 mm. In this embodiment, it is preferable that the thickness of the insulating part 11 is thicker than the thickness of the metal part 12, that is, the thickness of the thinnest part of the insulating part 11 is thicker than the thickness of the metal part 12.

絶縁転がり軸受の組み立て順は、まず、内輪２の内周面２ａに、略円筒部材の絶縁部１１を嵌め込む。この際、絶縁部１１の外周面１１ｂがテーパ状になっていると、寸法の相互差があっても内輪２に嵌め込むことができる。そのため、図２の構成に比べて、内輪２の内径と絶縁部１１の外径の締め代の管理を容易にできる。その後は、絶縁部１１の内周面１１ａに金属部１２を弾性変形させながら嵌め込むことで、絶縁ブッシュが得られる。 The assembly sequence for an insulating rolling bearing is as follows: first, the insulating part 11, which is a substantially cylindrical member, is fitted onto the inner circumferential surface 2a of the inner ring 2. At this time, if the outer circumferential surface 11b of the insulating part 11 is tapered, it can be fitted into the inner ring 2 even if there is a difference in dimensions. Therefore, compared to the configuration in Figure 2, it is easier to manage the interference between the inner diameter of the inner ring 2 and the outer diameter of the insulating part 11. After that, the insulating bushing is obtained by fitting the metal part 12 onto the inner circumferential surface 11a of the insulating part 11 while elastically deforming it.

絶縁ブッシュの更に他の形態を図４に示す。図４は、内輪および絶縁ブッシュの分解斜視図である。図４に示すように、絶縁ブッシュ１６は、円筒状の金属部１５の外周面にセラミックス溶射被膜からなる絶縁部１４が形成されたブッシュである。 Yet another form of insulating bush is shown in Figure 4. Figure 4 is an exploded perspective view of the inner ring and insulating bush. As shown in Figure 4, the insulating bush 16 is a bush in which an insulating part 14 made of a ceramic spray coating is formed on the outer circumferential surface of a cylindrical metal part 15.

セラミックスのベース材料としては、アルミナ、マグネシア、ジルコニア、チタニアなどの金属酸化物、窒化ケイ素、炭化珪素、またはこれらの混合物などが用いられる。溶射材の組成は、例えばアルミナの含有量９５．０～９８．５質量％とし、他の金属酸化物の含有量１．５～５．０質量％としてもよく、また、アルミナの含有量９７．０質量％以上、ジルコニアなどの金属酸化物の含有量１．５～２．５質量％とすれば、絶縁性と共に強度と靱性を向上させることができる。 The base material for ceramics may be metal oxides such as alumina, magnesia, zirconia, titania, silicon nitride, silicon carbide, or a mixture of these. The composition of the thermal spray material may, for example, contain 95.0 to 98.5 mass% alumina and 1.5 to 5.0 mass% other metal oxides. Also, if the alumina content is 97.0 mass% or more and the content of metal oxides such as zirconia is 1.5 to 2.5 mass%, it is possible to improve the strength and toughness as well as the insulation properties.

溶射法としては、大気中で行われる大気圧プラズマ溶射などの周知のプラズマ溶射法を採用できる。また、粉末式フレーム溶射法、高速ガス炎溶射法などの周知の溶射法を採用することもできる。 As a thermal spraying method, well-known plasma spraying methods such as atmospheric plasma spraying performed in the atmosphere can be used. Also, well-known thermal spraying methods such as powder flame spraying and high-velocity gas flame spraying can be used.

セラミックス溶射被膜の厚みは、３０μｍ～３００μｍが好ましい。３０μｍ未満であると、十分な絶縁性が得られないおそれがあり、３００μｍを超えると、製造コストが高くなる傾向がある。 The thickness of the ceramic spray coating is preferably 30 μm to 300 μm. If it is less than 30 μm, sufficient insulation may not be obtained, and if it exceeds 300 μm, the manufacturing costs tend to be high.

図４に示す形態の絶縁ブッシュを備える絶縁転がり軸受は、内輪２の内周面２ａに、セラミックス溶射被膜を外周面に有する金属部１５を締め代を持たせて嵌めたものである。締め代は、内輪２の材質とセラミックスの線膨張係数の差を鑑みて設定される。一般的に、内輪は軸受鋼が採用されるが、セラミックスに対して線膨張係数が高い。したがって、締め代は、使用環境範囲の高温側で内輪が膨張しても、金属部の外周面との締め代がなくならない値に設定される。一方、使用環境範囲の低温側では、内輪２は縮小するため、金属部１５に張り付く方向となる。そのため、熱衝撃試験を行った場合であっても絶縁ブッシュ１６が内輪２から脱落することを防止できる。また、この構成の場合、金属部１５の内周面に特殊な表面処理をする必要がなく、樹脂を射出成形する必要もない。また、金属部１５の外周面にセラミックスを溶射するので、内周面に溶射する場合に比べて低コスト化を図ることができる。さらに、シャフトが内輪と金属接触することがないので、絶縁性が保たれ、電食を防止する効果がある。 In the insulating rolling bearing having the insulating bush shown in FIG. 4, the metal part 15 having a ceramic spray coating on its outer peripheral surface is fitted to the inner peripheral surface 2a of the inner ring 2 with a clamping margin. The clamping margin is set in consideration of the difference in the linear expansion coefficient between the material of the inner ring 2 and the ceramics. Generally, the inner ring is made of bearing steel, which has a higher linear expansion coefficient than ceramics. Therefore, the clamping margin is set to a value that does not eliminate the clamping margin with the outer peripheral surface of the metal part even if the inner ring expands on the high temperature side of the operating environment range. On the other hand, on the low temperature side of the operating environment range, the inner ring 2 shrinks and is in the direction of sticking to the metal part 15. Therefore, even when a thermal shock test is performed, the insulating bush 16 can be prevented from falling off the inner ring 2. In addition, in this configuration, there is no need to perform a special surface treatment on the inner peripheral surface of the metal part 15, and there is no need to injection mold resin. In addition, since ceramics are sprayed on the outer peripheral surface of the metal part 15, it is possible to reduce costs compared to spraying on the inner peripheral surface. Furthermore, since there is no metallic contact between the shaft and the inner ring, insulation is maintained, which helps prevent electrolytic corrosion.

なお、絶縁性能を持たすために、内輪の内周面に直接セラミックスを溶射する方法も考えられるが、内周面に溶射可能な溶射材のサイズや形状は、溶射方法の兼ね合いで制限されてしまうため、コストが高くなる傾向がある。 It is also possible to spray ceramics directly onto the inner surface of the inner ring to provide insulation, but the size and shape of the material that can be sprayed onto the inner surface is limited by the spraying method, which tends to increase costs.

本発明の絶縁転がり軸受の構成は、上記図１～図４の構成に限らない、例えば、図１では玉軸受を示したが、本発明の絶縁転がり軸受は、円すいころ軸受、円筒ころ軸受、自動調心ころ軸受、針状ころ軸受、スラスト円筒ころ軸受、スラスト円すいころ軸受、スラスト針状ころ軸受、スラスト自動調心ころ軸受などにも適用できる。 The configuration of the insulating rolling bearing of the present invention is not limited to the configuration shown in Figures 1 to 4 above. For example, while a ball bearing is shown in Figure 1, the insulating rolling bearing of the present invention can also be applied to tapered roller bearings, cylindrical roller bearings, spherical roller bearings, needle roller bearings, thrust cylindrical roller bearings, thrust tapered roller bearings, thrust needle roller bearings, and thrust spherical roller bearings.

上記図１～図４の絶縁転がり軸受は、内輪の内周面に絶縁ブッシュを嵌合した構成としたが、これに限らない。例えば、外輪の外周面に、絶縁ブッシュ１０（図２参照）や、絶縁ブッシュ１３（図３参照）、絶縁ブッシュ１６（図４参照）などを嵌合して得られる軸受としてもよい。取り付け状態において、絶縁ブッシュの金属部は外輪の外周面に接触するように嵌合され、絶縁ブッシュの絶縁部はハウジングの内周面に接触するように嵌合される。この場合においても、絶縁部の外輪への抱き着きや、絶縁部の縮小に伴うハウジングからの脱落を防止できる。 The insulating rolling bearings in Figures 1 to 4 above are configured with an insulating bush fitted to the inner peripheral surface of the inner ring, but this is not limited to the configuration. For example, a bearing may be obtained by fitting an insulating bush 10 (see Figure 2), insulating bush 13 (see Figure 3), insulating bush 16 (see Figure 4), etc. to the outer peripheral surface of the outer ring. In the mounted state, the metal part of the insulating bush is fitted so as to contact the outer peripheral surface of the outer ring, and the insulating part of the insulating bush is fitted so as to contact the inner peripheral surface of the housing. Even in this case, it is possible to prevent the insulating part from clinging to the outer ring or from falling off the housing due to shrinkage of the insulating part.

また、図２および図３の構成では、絶縁部と金属部を別体で構成したが、金属部の外周面に樹脂組成物をインサート成形したり、樹脂塗料を各種の塗布方法によって塗布するなどして、樹脂成形体や樹脂塗膜を金属部と一体に構成してもよい。なおこの場合も、金属部を割ブッシュにすることが好ましい。また、絶縁部と金属部との間に他の層を介在させてもよい。 In the configurations of Figures 2 and 3, the insulating part and the metal part are constructed as separate bodies, but the resin molded body or the resin coating may be integrally constructed with the metal part by insert molding a resin composition on the outer peripheral surface of the metal part or by applying a resin paint by various application methods. In this case, it is also preferable to make the metal part a split bush. Also, another layer may be interposed between the insulating part and the metal part.

本発明の絶縁転がり軸受は、例えば、冷媒圧縮機の電動機に使用される電食防止軸受や、電動モータの電食防止軸受に使用される。また、後述の実施例で示すように、－３０℃～１６０℃の熱衝撃試験においても十分な抜去力を有することから、低温条件から高温条件まで幅広い温度域で使用される電食防止軸受に特に適している。例えば、０℃以下および１００℃以上の両温度域で使用される電食防止軸受に適用される。 The insulating rolling bearing of the present invention is used, for example, as an electrolytic corrosion prevention bearing used in the electric motor of a refrigerant compressor, or as an electrolytic corrosion prevention bearing for an electric motor. As shown in the examples below, the bearing has sufficient removal force even in thermal shock tests at -30°C to 160°C, and is therefore particularly suitable for electrolytic corrosion prevention bearings used in a wide range of temperatures from low to high. For example, the bearing is applied to electrolytic corrosion prevention bearings used in both temperature ranges below 0°C and above 100°C.

実施例１
ＰＥＥＫ樹脂を射出成形して、円筒部材を得た。この円筒部材をＳＵＪ２製の内輪の内周面に嵌合して、さらに、その円筒部材の内周面にＳＵＳ３０４製の割ブッシュを嵌合して、図２に示す形態の試験用部材を得た。 Example 1
A cylindrical member was obtained by injection molding of PEEK resin. This cylindrical member was fitted to the inner peripheral surface of an inner ring made of SUJ2, and further, a split bush made of SUS304 was fitted to the inner peripheral surface of the cylindrical member, thereby obtaining a test member having the configuration shown in FIG.

実施例２
ＰＥＥＫ樹脂を射出成形して、外周面がテーパ状の円筒部材を得た。この円筒部材をＳＵＪ２製の内輪の内周面に嵌合し、さらに、その円筒部材の内周面にＳＵＳ３０４製の割ブッシュを嵌合して、図３に示す形態の試験部材を得た。 Example 2
A cylindrical member with a tapered outer circumferential surface was obtained by injection molding of PEEK resin. This cylindrical member was fitted to the inner circumferential surface of an inner ring made of SUJ2, and a split bush made of SUS304 was further fitted to the inner circumferential surface of the cylindrical member to obtain a test member having the configuration shown in FIG.

実施例３
オーステナイト系ステンレス鋼製の円筒部材の外周面に大気プラズマ溶射を行ない、セラミックス溶射被膜を有する絶縁ブッシュを得た。溶射材には、アルミナを使用した。 Example 3
The outer peripheral surface of a cylindrical member made of austenitic stainless steel was subjected to atmospheric plasma spraying to obtain an insulating bushing having a ceramic sprayed coating. Alumina was used as the spray material.

比較例１
ＰＥＥＫ樹脂を射出成形して、絶縁部単体からなる絶縁ブッシュを得た。この絶縁ブッシュをＳＵＪ２製の内輪の内周面に嵌合して、図５（ａ）に示す形態の試験部材を得た。 Comparative Example 1
An insulating bushing consisting of a single insulating portion was obtained by injection molding of PEEK resin. This insulating bushing was fitted onto the inner peripheral surface of an inner ring made of SUJ2 to obtain a test member having the configuration shown in FIG. 5(a).

比較例２
ＳＵＳ３０４製の円筒部材の内周面にアマルファ処理を施して微細凹凸形状を形成した後、その内周面にＰＰＳ樹脂をインサート成形して、射出成形層を有する絶縁ブッシュを得た。この絶縁ブッシュをＳＵＪ２製の内輪の内周面に嵌合して、図５（ｂ）に示す形態の試験部材を得た。 Comparative Example 2
The inner peripheral surface of a cylindrical member made of SUS304 was subjected to an amalgamation process to form a fine uneven shape, and then PPS resin was insert-molded onto the inner peripheral surface to obtain an insulating bushing having an injection-molded layer. This insulating bushing was fitted onto the inner peripheral surface of an inner ring made of SUJ2 to obtain a test member having the configuration shown in Figure 5(b).

実施例１～３および比較例１～２に用いた部品の材質の線膨張係数を表１に示す。 The linear expansion coefficients of the materials used in Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

Figure 0007488725000001
Figure 0007488725000001

＜抜去力試験＞
各試験部材の軸孔にＳ４５製の軸を挿入したものを恒温槽に入れ、熱衝撃を繰り返し加えた。熱衝撃は、１６０℃、３０分の高温条件と、－３０℃、３０分の低温条件を１セットとして２００サイクル行った。２００サイクル後に軸を抜き、その試験部材に対して、以下の条件で抜去力試験を行った。
測定器 ：オートグラフ
測定速度：５ｍｍ／ｓｅｃ
判定基準：２００Ｎ以上 <Removal force test>
Each test member was inserted with a shaft made of S45 in the shaft hole and placed in a thermostatic chamber, where it was repeatedly subjected to thermal shock. The thermal shock was performed for 200 cycles, with one set consisting of a high-temperature condition of 160°C for 30 minutes and a low-temperature condition of -30°C for 30 minutes. After 200 cycles, the shaft was removed, and the test member was subjected to a removal force test under the following conditions.
Measuring instrument: Autograph Measuring speed: 5 mm/sec
Judgment criteria: 200N or more

抜去力試験の概略を図６に示す。図６に示すように、受け治具１８の上に、熱衝撃を加えた後の試験部材１７を置き、その試験部材１７の内輪１７ａの内周面に嵌合された絶縁ブッシュ１７ｂの端面に押し治具１９を当てた。押し治具１９に対して矢印の向きに荷重をかけ、絶縁ブッシュ１７ｂが受け治具１８に抜けきるまでの荷重のピークを測定した。荷重が２００Ｎ以上を合格として、試験数に対する合格数を表１に示す。 The outline of the removal force test is shown in Figure 6. As shown in Figure 6, the test member 17 after the thermal shock was applied was placed on the receiving jig 18, and a pressing jig 19 was applied to the end face of the insulating bush 17b fitted to the inner peripheral surface of the inner ring 17a of the test member 17. A load was applied to the pressing jig 19 in the direction of the arrow, and the peak load was measured until the insulating bush 17b was completely removed from the receiving jig 18. A load of 200N or more was considered a pass, and the number of passes for each test is shown in Table 1.

＜通電試験＞
通電試験の概略を図７に示す。図７に示すように、試験部材１７に鉄製のシャフトＳを挿入し、そのシャフトＳと試験部材１７の内輪１７ａの外周面とに絶縁抵抗測定器２０の各端子を当てて、以下の条件で絶縁抵抗値を測定した。各試験例において、３サンプルずつ測定を行い、その平均値を表１に示す。
印加電圧：ＤＣ５００Ｖ
温度 ：１５～２５℃（室温）
湿度 ：４０～６０％ <Electrical test>
An outline of the electrical current test is shown in Fig. 7. As shown in Fig. 7, an iron shaft S was inserted into the test member 17, and the terminals of an insulation resistance tester 20 were placed against the shaft S and the outer circumferential surface of the inner ring 17a of the test member 17, and the insulation resistance value was measured under the following conditions. For each test example, three samples were measured, and the average value is shown in Table 1.
Applied voltage: DC 500V
Temperature: 15-25°C (room temperature)
Humidity: 40-60%

Figure 0007488725000002
Figure 0007488725000002

表２に示すように、実施例１～３および比較例２は、全ての試験数において合格した上、抜去力１０００Ｎ以上を示し、熱衝撃試験後でも十分な抜去力を有していた。また、実施例１～３および比較例２は、軸への抱き着きも見られなかった。ただし、比較例２の場合、高温時には外径側の金属部の形状拘束を受け、体積膨張が内径側へ逃げる結果、内径寸法が小さくなる可能性が考えられる。これに対して、実施例１～３は、絶縁部が内輪と金属部に挟まれ、かつ、金属部によって内輪に押し付けられる方向に付勢されているので、温度変化に伴う絶縁部の体積変化を抑制でき、内径の寸法安定性に一層優れると考えられる。 As shown in Table 2, Examples 1 to 3 and Comparative Example 2 passed all tests, and showed a removal force of 1000 N or more, which was sufficient even after the thermal shock test. Furthermore, Examples 1 to 3 and Comparative Example 2 did not show any adhesion to the shaft. However, in the case of Comparative Example 2, at high temperatures, the shape of the metal part on the outer diameter side is restricted, and volume expansion escapes to the inner diameter side, which may result in a smaller inner diameter dimension. In contrast, in Examples 1 to 3, the insulating part is sandwiched between the inner ring and the metal part, and is biased by the metal part in a direction pressed against the inner ring, so that volume change of the insulating part due to temperature change can be suppressed, and the dimensional stability of the inner diameter is thought to be even better.

一方、比較例１は、熱衝撃試験後において、全ての試験数で絶縁ブッシュが軸に抱き着いたため、絶縁ブッシュと軸が内輪から一緒に抜ける結果となった（図８参照）。試験数５つのうち合格数は１つであり、残りの不合格数４つのうち３つは、絶縁ブッシュの縮小によって内輪と絶縁ブッシュとの締め代がなくなり、絶縁ブッシュと軸が内輪から自重で抜ける結果となった。さらに、図８に示すように、絶縁ブッシュに割れも確認された。 On the other hand, in Comparative Example 1, after the thermal shock test, the insulating bush clung to the shaft in all tests, resulting in the insulating bush and shaft coming out of the inner ring together (see Figure 8). Of the five tests, one passed, and of the remaining four failed tests, three were due to the insulating bush shrinking, eliminating the clamping margin between the inner ring and the insulating bush, causing the insulating bush and shaft to come out of the inner ring under their own weight. Furthermore, cracks were confirmed in the insulating bush, as shown in Figure 8.

通電試験では、いずれの例も、シャフトが内輪の内周面と金属接触することがなく、絶縁性が示された。 In the electrical current test, the shaft did not come into metallic contact with the inner surface of the inner ring in any of the examples, demonstrating insulation.

続いて、比較例２の絶縁ブッシュの製造コストを１とした場合における、他の絶縁ブッシュの製造コストを数値化した。結果を図９に示す。 Next, the manufacturing costs of the other insulating bushes were quantified, assuming that the manufacturing cost of the insulating bush in Comparative Example 2 was 1. The results are shown in Figure 9.

図９に示すように、比較例２の絶縁ブッシュは、特殊な表面処理が必要であり、また射出成形であるため、他に比べて、コスト増になった。一方、実施例１および実施例２の絶縁ブッシュは、金属部と絶縁部が、割ブッシュと樹脂製の円筒部材で構成され、特殊な表面処理や射出成形を必要としないため、製造コストを大幅に低減できる。特に、実施例２は、樹脂製の円筒部材の外周面がテーパ形状であり、寸法の相互差があっても内輪に嵌め込むことができるため、製造コストをより低減できる。また、実施例３の絶縁ブッシュは、セラミックスの溶射が必要であるものの、外周面に溶射しているため、内周面に溶射する場合に比べて、製造コストを低減できる。例えば、セラミックス溶射において、内周面に溶射した場合の製造コストを１とすると、外周面に溶射した場合の製造コストは０．４程度となる（図１０参照）。 As shown in FIG. 9, the insulating bushing of Comparative Example 2 requires special surface treatment and is injection molded, so the cost is higher than the others. On the other hand, the insulating bushings of Examples 1 and 2 have metal parts and insulating parts that are composed of a split bushing and a resin cylindrical member, and do not require special surface treatment or injection molding, so the manufacturing cost can be significantly reduced. In particular, in Example 2, the outer surface of the resin cylindrical member is tapered, and it can be fitted into the inner ring even if there is a difference in dimensions, so the manufacturing cost can be further reduced. In addition, although the insulating bushing of Example 3 requires ceramic spraying, since it is sprayed on the outer surface, the manufacturing cost can be reduced compared to when it is sprayed on the inner surface. For example, in ceramic spraying, if the manufacturing cost when spraying on the inner surface is 1, the manufacturing cost when spraying on the outer surface is about 0.4 (see FIG. 10).

以上のように、本発明の絶縁転がり軸受は、幅広い温度域においても軸への抱き着きや内輪からの脱落を防止でき、寸法安定性を維持できるため、軸を安定して支持することができる。また、絶縁転がり軸受の低コスト化も図ることができる。 As described above, the insulated rolling bearing of the present invention can prevent the bearing from clinging to the shaft or falling off the inner ring even over a wide temperature range, and can maintain dimensional stability, so it can stably support the shaft. It can also reduce the cost of the insulated rolling bearing.

本発明の絶縁転がり軸受は、電食を防止するとともに、軸などへの抱き着きや、内輪などからの脱落を防止できるので、電動モータの軸や冷媒圧縮機の軸を支持する電食防止軸受として広く利用することができる。 The insulating rolling bearing of the present invention prevents electrolytic corrosion and also prevents the bearing from clinging to shafts and falling off inner rings, so it can be widely used as an electrolytic corrosion prevention bearing to support the shafts of electric motors and refrigerant compressors.

１ 絶縁転がり軸受
２ 内輪
３ 外輪
４ 玉
５ 保持器
６ シール部材
７ グリース
８ 絶縁部
９ 金属部
１０ 絶縁ブッシュ
１１ 絶縁部
１２ 金属部
１３ 絶縁ブッシュ
１４ 絶縁部
１５ 金属部
１６ 絶縁ブッシュ
１７ 試験部材
１８ 受け治具
１９ 押し治具
２０ 絶縁抵抗測定器
Ｓ シャフト REFERENCE SIGNS LIST 1 Insulated rolling bearing 2 Inner ring 3 Outer ring 4 Balls 5 Cage 6 Sealing member 7 Grease 8 Insulating part 9 Metal part 10 Insulating bush 11 Insulating part 12 Metal part 13 Insulating bush 14 Insulating part 15 Metal part 16 Insulating bush 17 Test member 18 Receiving jig 19 Pressing jig 20 Insulation resistance measuring instrument S Shaft

Claims (3)

鋼材からなる内輪および外輪と、この内・外輪間に介在する複数の転動体と、前記内輪の内周面または前記外輪の外周面に嵌合された略円筒状の絶縁ブッシュとを備えた絶縁転がり軸受であって、
前記絶縁ブッシュは、外径側に樹脂組成物からなる絶縁部と、内径側に金属部とを有し、前記絶縁部と前記金属部が別体で構成されており、
前記金属部は、周方向の一部に合い口が形成された割ブッシュであり、前記絶縁部は、前記割ブッシュの合い口を外径側から覆う円筒部材であり、前記絶縁部の外周面は、軸方向の一方側から他方側に向かって拡径するテーパ形状であることを特徴とする絶縁転がり軸受。 An insulating rolling bearing comprising an inner ring and an outer ring made of steel, a plurality of rolling elements interposed between the inner and outer rings, and a substantially cylindrical insulating bush fitted onto an inner peripheral surface of the inner ring or an outer peripheral surface of the outer ring,
the insulating bushing has an insulating portion made of a resin composition on an outer diameter side and a metal portion on an inner diameter side, the insulating portion and the metal portion being configured as separate bodies;
the metal part is a split bushing having a joint formed in part of a circumferential direction, the insulating part is a cylindrical member covering the joint of the split bushing from an outer diameter side, and the outer circumferential surface of the insulating part has a tapered shape that expands in diameter from one side to the other side in the axial direction . 前記絶縁部の前記樹脂組成物のベース樹脂が、ポリフェニレンサルファイド樹脂、ポリエーテルケトン系樹脂、テトラフルオロエチレン－パーフルオロアルキルビニルエーテル共重合体樹脂、テトラフルオロエチレン－ヘキサフルオロプロピレン共重合体樹脂、またはテトラフルオロエチレン－エチレン共重合体樹脂であることを特徴とする請求項１記載の絶縁転がり軸受。 The insulating rolling bearing according to claim 1, characterized in that the base resin of the resin composition of the insulating part is polyphenylene sulfide resin, polyether ketone resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, or tetrafluoroethylene-ethylene copolymer resin. 前記金属部が機械構造用炭素鋼またはステンレス鋼であることを特徴とする請求項１または請求項２記載の絶縁転がり軸受。 3. The insulating rolling bearing according to claim 1, wherein the metal portion is made of carbon steel or stainless steel for mechanical construction.
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