JP2005017251A - Fixture and method for measuring insulation resistance of insulated bearing - Google Patents

Fixture and method for measuring insulation resistance of insulated bearing Download PDF

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JP2005017251A
JP2005017251A JP2003186471A JP2003186471A JP2005017251A JP 2005017251 A JP2005017251 A JP 2005017251A JP 2003186471 A JP2003186471 A JP 2003186471A JP 2003186471 A JP2003186471 A JP 2003186471A JP 2005017251 A JP2005017251 A JP 2005017251A
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film
outer ring
insulation resistance
jig
bearing
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JP4369692B2 (en
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Hideji Ito
秀司 伊藤
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NTN Corp
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NTN Corp
NTN Toyo Bearing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixture and a method capable of obtaining a sufficient contact ratio between an insulating film of the outer ring of an insulated bearing and each film touching object to be brought into contact with it, and capable of measuring the insulation resistance value of the insulated bearing precisely, and to prevent the insulating film of the outer ring and the film touching objects from being worn, when the insulated bearing is fitted into the jig. <P>SOLUTION: Film touching objects 4, 5 which touch the insulating film 32a of the outer ring 32 of the insulated bearing 30, and are connected to an ohm-meter 6 are provided. These touching objects 4, 5 are made of a conductive polymer such as conductive rubber or the like. The touching objects 4, 5 are fitted to the inside surfaces of the jig body 2 and a lid member 3. The jig body 2 is in the shape of a split-into-two ring. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、鉄道車両主電動機や発電機、汎用モータ等に使用される絶縁軸受の絶縁抵抗を測定する絶縁抵抗測定治具および測定方法に関する。
【０００２】
【従来の技術】
電動機等のように、ハウジングと軸の間で大きな電位差が生じる箇所に使用される軸受では、電食を防止するために、外輪の外径面および幅面を絶縁皮膜で覆った絶縁軸受が用いられている。絶縁皮膜には樹脂やセラミックス等が用いられる。この種の絶縁軸受として、絶縁皮膜の外層に金属膜を形成したものがある。
このような金属膜を有する絶縁軸受の絶縁性能を測定する場合は、外輪最外層の金属層と外輪母材とに、抵抗計のアース側端子とライン側端子を接続することで、最外層の金属層が電極として利用でき、外輪の絶縁皮膜全域についての絶縁抵抗値が測定される。
一方、絶縁皮膜が表面に露出した絶縁軸受では、絶縁皮膜の一部に端子を接触させただけでは、絶縁皮膜の局部的な絶縁抵抗値しか測定することができない。
全体の絶縁抵抗値を測定するには、治具として、図８，図９に示すような外輪外径面に接触させるハウジング４２、および幅面に接触させる蓋部材４３を用い、その中に組み入れた状態で測定する必要がある。従来では、測定を容易に行うために、ハウジング４２を２つ割りのものとし、１８０°位置でボルトによる締め付けを行い、側面から蓋部材４３を取り付けるようにしている。抵抗計６の両端子は、ハウジング４２と外輪母材３２ｂとに接続する。このような治具を用いると、ハウジング４２への軸受単体３０の圧入や引き抜き作業が不要となり、プレス機等を用いることなく、手作業だけで絶縁抵抗値を測定できる。なお、図８（Ａ）は、図８（Ｂ）におけるＶＩＩＩ−ＶＩＩＩ矢視断面図に相当する断面図である。
【０００３】
【発明が解決しようとする課題】
絶縁皮膜が溶射加工されたセラミックスによる１層構造の絶縁軸受の場合も図８，図９のような治具が用いられることになるが、その場合、以下のような問題がある。絶縁軸受として使用する場合、絶縁被膜３２ａの表面を研磨加工によって正規寸法、粗さに仕上げているが、正規寸法、粗さに仕上げている状態であっても２つ割ハウジング４２をボルト締めする時に、ハウジング内面と絶縁被膜３２ａの接触部において微小な滑りが生じるが、ハウジング４２の金属材料に比べてセラミックス製の絶縁被膜３２ａの方が硬度が高いことから、僅かではあるがハウジング４２が摩耗する現象がみられる。この摩耗により、ハウジング４２の内径寸法が繰返し使用によって変化し、絶縁被膜３２ａとの締め代が保てなくなると、接触不良が発生し、正確な絶縁抵抗値を測定することが出来なくなる。また、摩耗粉が絶縁被膜の表面にこびり付くので、その洗浄に非常に手間取るという問題点もある。蓋部材４３の取付けにおいても、丁寧な締め付け作業をしないと、ハウジング４２の場合と同様な現象が生じる。又、上記では絶縁被膜３２ａの表面を研磨加工した時の問題点について挙げたが、実際には研磨加工前の状態でも絶縁抵抗検査を実施する場合がある。この検査は万一溶射不良などによって絶縁不良となっているものを研磨加工前に確認し、不良品を研磨加工しない様に実施するものであるが、研磨加工されていない絶縁被膜３２ａの表面は一般的に粗面であり、ハウジング４２と絶縁被膜３２ａの接触率が低くなり、精度の良い測定を行えないという問題がある。
尚、外輪の絶縁被膜３２ａが樹脂製の場合には、上記治具を用いて測定した場合に、上記の滑りが生じても、ハウジング４２と絶縁被膜３２ａの両方に摩耗が生じることは無い。これは絶縁被膜３２ａが樹脂製である為、弾性があることから微小すべりに対し、追随出来る為である。
【０００４】
この発明の目的は、軸受外輪の絶縁皮膜とこれに接触させる皮膜接触体との間の優れた接触率が得られて、絶縁軸受の絶縁抵抗値を正確に測定することのできる絶縁抵抗測定治具および絶縁抵抗測定方法を提供することである。
【０００５】
【課題を解決するための手段】
この発明の絶縁軸受の絶縁抵抗測定治具は、外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する治具であって、上記絶縁軸受の外輪の絶縁皮膜に接触して抵抗計と接続される皮膜接触体が導電性高分子からなるものとしている。上記導電性高分子は、導電性ゴム、または導電性プラスチック等である。
この構成によると、皮膜接触体が導電性高分子からなるため、皮膜接触体がその弾性変形により、絶縁皮膜の表面粗さによる凹凸に容易になじみ、凹凸に対して局部的な接触とならずに優れた接触率が得られる。そのため正確な絶縁抵抗値の測定が行える。特に、絶縁皮膜がセラミックス溶射層であり、溶射表面の状態である場合、研磨加工面と比較すれば一般的に粗面であり、皮膜接触体が金属材では接触率が低くて測定が困難があるが、このようなセラミックス溶射層からなる絶縁皮膜に対しても、導電性高分子の皮膜接触体を用いれば、高い接触率が得られて精度の良い絶縁抵抗値の測定が行える。また、皮膜接触体が弾性変形可能であるため、皮膜接触体を絶縁皮膜に押しつけるときに若干の滑りが生じたとしても、弾性変形することで摩耗が防止される。
皮膜接触体は、導電性高分子の中でも、弾性に優れた導電性ゴムが、絶縁皮膜の凹凸になじみ易いことで好ましいが、導電性プラスチックであっても、ある程度の弾性はあるため、皮膜接触体を金属材とした場合に比べて接触性が改善される。
【０００６】
この発明において、絶縁抵抗測定治具が、絶縁軸受の外輪を内周に嵌合させかつ上記外輪の片方の幅面に対向する鍔部を有する２つ割りのリング状の治具本体と、この治具本体に着脱可能に取付けられ上記外輪のもう片方の幅面に対向する蓋部材と、上記治具本体の内周面および鍔部の内面、並びに上記蓋部材の内面に設けられて上記外輪の絶縁皮膜に接触し上記抵抗計と接続される皮膜接触体とを有するものとしても良い。
この構成の場合、外輪の外径面から幅面にわたる絶縁皮膜の略全体に皮膜接触体を接触させることができて、より精度の高い測定が行える。また、治具本体が２つ割りのリング状であるため、治具への絶縁軸受の出し入れが容易である。このような２つ割りの治具本体を用いた場合に、両側の治具本体を相互に締め付けるときに、絶縁皮膜表面と治具本体の内面との間で微小滑りを生じるが、この微小滑りに対し、皮膜接触体が導電性高分子であることで、その弾性によって追随できる。そのため、治具および絶縁皮膜が共に摩耗を生じることなく、絶縁抵抗値を測定することができる。
【０００７】
この発明において、皮膜接触体が、絶縁軸受の外輪を内周に嵌合させかつ上記外輪の片方の幅面に接触する鍔部を有する２つ割りのリング状の治具本体と、この治具本体に着脱可能に取付けられ上記外輪のもう片方の幅面に接触する蓋部材とでなるものとしても良い。
この構成の場合、治具本体が皮膜接触体で構成されるため、別体の治具本体に皮膜接触体を取付けるものに比べて構成が簡単である。この構成の場合も、外輪の外径面から幅面にわたる絶縁皮膜の略全体に皮膜接触体を接触させることができて、精度の高い測定が行える。また、治具本体が２つ割りのリング状であるため、治具への絶縁軸受の出し入れが容易である。２つ割りの両側の治具本体を相互に締め付けるときに、上記と同様に絶縁皮膜表面と治具本体の内面との間で微小滑りを生じるが、この微小滑りに対し、治具本体となる皮膜接触体が導電性高分子であることで、その弾性によって追随できる。そのため、治具および絶縁皮膜が共に摩耗を生じることなく、絶縁抵抗値を測定することができる。
【０００８】
この発明において、上記皮膜接触体が、上記絶縁軸受の外輪の幅面に接触するリング状の部材であっても良い。
この構成の場合、外輪の幅面の絶縁皮膜のみに皮膜接触体を接触させて測定することになるが、皮膜接触体が弾性変形により絶縁皮膜の表面の凹凸になじんで高い接触率が得られ、また全周に渡って接触させることになるため、精度良く絶縁抵抗を測定することができる。また、リング状の皮膜接触体の単体からなる絶縁抵抗測定治具であるため、構成が非常に簡素なものとなる。
【０００９】
この発明において、上記皮膜接触体が、上記絶縁軸受の外輪の外径面に弾性的に被せられるリング状の部材であっても良い。
この構成の場合、外輪の外径面の絶縁皮膜のみに皮膜接触体を接触させて測定することになるが、皮膜接触体が弾性変形により絶縁皮膜の表面の凹凸になじんで高い接触率が得られ、また全周に渡って接触させることになるため、精度良く絶縁抵抗を測定することができる。外輪の外径面に弾性的に被せられるリング状の皮膜接触体の単体からなる絶縁抵抗測定治具であるため、この場合も、構成が非常に簡素なものとなる。
【００１０】
この発明において、上記絶縁軸受の外輪の円周方向の一部が進入可能な凹部を有する治具本体と、この治具本体の上記凹部の開口に平面的に張られて上記外輪を接触させる膜状の皮膜接触体とでなるものとしても良い。
この構成の場合、平面的に張られた皮膜接触体に外輪を押しつけることで、皮膜接触体が外輪外径面に沿って弾性変形し、その外輪外径面の絶縁皮膜に接触することになる。この場合、絶縁皮膜の円周方向の一部における絶縁抵抗の測定となるが、その一部において、皮膜接触体と絶縁皮膜との高い接触率が得られ、絶縁抵抗値を精度良く測定できる。
【００１１】
この発明の絶縁軸受の絶縁抵抗測定方法は、外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する絶縁抵抗測定方法であって、導電性高分子からなる皮膜接触体を上記絶縁軸受の外輪の絶縁皮膜に接触させ、この皮膜接触体と上記外輪の絶縁皮膜で覆われていない部分との間に抵抗計を接続して上記絶縁軸受の絶縁抵抗値を測定する方法である。
この構成によると、皮膜接触体が導電性高分子からなるため、皮膜接触体がその弾性変形により、絶縁皮膜の表面粗さによる凹凸に容易になじみ、凹凸に対して局部的な接触とならずに優れた接触率が得られる。そのため正確な絶縁抵抗値の測定が行える。また、皮膜接触体が弾性変形可能であるため、皮膜接触体を絶縁皮膜に押しつけるときに若干の滑りが生じたとしても、弾性変形にすることが摩耗が防止される。
【００１２】
【発明の実施の形態】
この発明の第１の実施形態を図１ないし図３と共に説明する。図１は絶縁抵抗測定治具の単独の状態を、図２は測定対象となる絶縁軸受を、図３は絶縁抵抗測定治具に絶縁軸受を組み込んだ状態をそれぞれ示す。図２に示すように、測定対象となる絶縁軸受３０は、外輪３２に絶縁皮膜３２ａを有するものである。この絶縁軸受３０は、内輪３１と外輪３２の間に転動自在にボールからなる複数の転動体３３を介在させた転がり軸受であって、外輪３２の外径面から両幅面にわたって１層構造の絶縁皮膜３２ａが形成されている。これにより内輪３１が嵌合する軸（図示せず）と、外輪３２を支持するハウジング（図示せず）との間が電気的に絶縁分離される。絶縁皮膜３２ａは、セラミックス製の皮膜であり、外輪３２の母材３２ｂの表面にセラミックスを溶射することによって形成される。絶縁皮膜３２ａは樹脂製であっても良い。
【００１３】
図１に示すように、この絶縁抵抗測定治具１は、治具本体２と、蓋部材３と、皮膜接触体４，５とを有する。治具本体２は、絶縁軸受３０の外輪３２を内周に嵌合させる２つ割りのリング状であって、かつ外輪３２の片方の幅面に対向する鍔部２ａを有する。蓋部材３は、治具本体２に着脱自在に取付けられ上記外輪３２のもう片方の幅面に対向するリング状の部材である。皮膜接触体４，５は、治具本体２の内周面および鍔部２ａの内面、並びに蓋部材３の内面にそれぞれ設けられ、絶縁軸受３０の外輪３２の絶縁皮膜３２ａに接触するものである。この皮膜接触体４，５と外輪３２の母材３２ｂとの間に、抵抗計６（図３）が接続される。
皮膜接触体４，５の材料は、導電性ゴムまたは導電性プラスチック等の導電性高分子であり、ここでは導電性ゴムが用いられる。皮膜接触体４，５となる導電性ゴムとしては、体積固有抵抗率１．７Ω・ｃｍ、厚さ２ｍｍのものが使用される。上記導電性ゴムは、ニトリル系、アクリル系、フッ素系、シリコン系等のゴム材料に、カーボンパウダーやカーボン繊維等の導電物質を、製造過程で混入させることで、製造される。混入させる導電物質の形状は、必ずしもパウダー状や繊維状でなくても良く、例えばゴム加硫成形後に後述する所定の硬さや体積固有抵抗率が得られれば良い。
【００１４】
治具本体２は、正面形状がＣ字状の２つの金属製の分割本体２Ａ，２Ｂからなる。各分割本体２Ａ，２Ｂの両端には、両分割本体２Ａ，２Ｂを互いにボルト締めしてリング状に連結するための取付片２ｂがそれぞれ外径側に突出して設けられている。一方の分割本体２Ａの両取付片２ｂにはボルト挿通孔７が設けられ、他方の分割本体２Ｂの両取付片２ｂには上記ボルト挿通孔７に整合するねじ孔８がそれぞれ設けられている。両分割本体２Ａ，２Ｂは、ボルト挿通孔７に挿通させたボルト１０を、対応するねじ孔８に螺合させることによりボルト締めされ、リング状の治具本体２とされる。治具本体２の鍔部２ａを有する側面とは反対側の側面の周方向の複数箇所には、上記蓋部材３をボルト締めするためのねじ孔９が設けられる。この側面にボルト締めされる蓋部材３には、上記ねじ孔９に整合する複数のボルト挿通孔（図示せず）が設けられている。これらのボルト挿通孔に挿通させたボルト１１を対応する各ねじ孔９に螺合させることにより、図１（Ａ）のように治具本体２の鍔部２ａ側とは反対側の側面に蓋部材３がボルト締めされる。なお、図１（Ａ）は、図１（Ｂ）におけるＩ−Ｉ矢視断面図に相当する断面図である。
【００１５】
治具本体２を構成する両分割本体２Ａ，２Ｂをボルト締めして、これら両分割本体２Ａ，２Ｂの合わせ面１２，１３（図１（Ｂ））が全面接触した状態で、皮膜接触体４の内径寸法Ｄ１は、この絶縁抵抗測定治具１に組み込まれる絶縁軸受３０の外輪絶縁皮膜３２ａの外径寸法より僅かに小さくなるように加工されている。また、治具本体２と蓋部材３の合わせ面１４，１５（図１（Ａ））が全面接触した状態で、治具本体２側の皮膜接触体４の鍔部２ａの内面の部分４ａと、蓋部材３側の皮膜接触体５の間の寸法Ｗは、この絶縁抵抗測定治具１に組み込まれる絶縁軸受３０の幅寸法より僅かに小さくなるように加工されている。このように加工されることにより、両分割本体２Ａ，２Ｂをボルト締めして治具本体２を構成し、さらに治具本体２に蓋部材３をボルト締めして絶縁抵抗測定治具１内に絶縁軸受１を組み込むことで、皮膜接触体４，５と外輪３２の絶縁皮膜３２ａとが所定の締め代をもって接触する。
【００１６】
図３に示すように、絶縁軸受３０を絶縁抵抗測定治具１に組み込んだ状態で、軸受外輪３２の絶縁皮膜３２ａの表面全域は、治具本体２および蓋部材３の皮膜接触体４，５に接触する。この状態で、抵抗計６のアース端子を絶縁抵抗測定治具１の外表面に、ライン端子を外輪３２の母材３２ｂにそれぞれ接続して、絶縁抵抗測定治具１と外輪３２の母材３２ｂとの間の絶縁抵抗値を計測する。
【００１７】
この実施形態の絶縁抵抗測定治具１を用いると、導電性ゴムからなる皮膜接触体４，５が絶縁軸受３０の外輪絶縁皮膜３２ａ表面に接触するので、絶縁抵抗測定治具１をボルト１０，１１で締め付けて絶縁軸受３０を組み込む際に、絶縁皮膜３２ａの表面と絶縁抵抗測定治具１の内面との間に生じる微小滑りに対して、皮膜接触体４，５がその弾性変形により絶縁皮膜３２ａの表面に良く追従して接触することができる。そのため、上記微小滑りに起因して絶縁抵抗測定治具１および絶縁皮膜３２ａが摩耗することがなく、絶縁抵抗値を正確に測定できる。特に、絶縁皮膜３２ａが溶射によるセラミックス製である場合、その表面は粗面であるが、導電性ゴムからなる皮膜接触体４，５がその弾性変形でセラミックス製絶縁皮膜３２ａの表面の凹凸部に容易に追随するので、皮膜接触体４，５と絶縁皮膜３２ａの接触率が高くなり、正確な絶縁抵抗値を測定することができる。
【００１８】
また、絶縁抵抗測定治具１は、皮膜接触体４を設けた２つ割りのリング状の治具本体２と、皮膜接触体５が設けられた蓋部材３とからなり、この絶縁抵抗測定治具１に絶縁軸受３０を組み込んだ状態で絶縁軸受３０の絶縁抵抗値を測定するので、外輪絶縁皮膜３２ａの外径面から幅面にわたる全面に接触して絶縁抵抗値を測定でき、より精度の良い測定が行える。
【００１９】
この実施形態の絶縁抵抗測定治具１の性能を確認するため、上記測定系の場合と、図８および図９に示す従来の絶縁抵抗測定治具４１を用いた測定系とで同じ絶縁軸受３０の電気的特性を比較した。その結果を、次の表１に示す。
【００２０】
【表１】

Figure 2005017251
【００２１】
表１は、上記各測定系において、絶縁抵抗測定治具１，４１の表面と外輪母材３２ｂとの間に５００Ｖの電圧を印加した場合に、絶縁軸受３０を流れる電流値（Ａ）を計測した場合の比較結果を示す。この表１の結果によると、皮膜接触体４，５を用いた実施形態の場合の方が、従来例の場合に比べて高い電流値となっている。絶縁抵抗値は、理論的には絶縁皮膜３２ａの表面積が大きくなるほど低くなることから、表１の結果は、絶縁抵抗測定治具１，４１と絶縁皮膜３２ａの実接触面積が、皮膜接触体４，５を用いたこの実施形態の場合の方が大きく、より正確に絶縁抵抗値を測定できることを示している。
【００２２】
また、この実施形態における皮膜接触体４，５自体の絶縁抵抗値への影響を確認するために、外輪の表面に絶縁皮膜を形成し、さらにその表面に金属層（導電体）を形成した別の絶縁軸受について、この実施形態の絶縁抵抗測定治具１と、図８および図９に示す従来例の絶縁抵抗測定治具４１とで絶縁抵抗値を測定する試験を行った。この試験結果では、実施形態の場合も従来例の場合も共に５０ＭΩ（５００Ｖ印加時）となっていて、皮膜接触体４，５の影響は認められなかった。なお、この試験では、軸受外輪の最外層が導電体であるため、軸受外輪と絶縁抵抗測定治具の実接触率による抵抗値への影響は殆ど無い。
【００２３】
また、この実施形態では皮膜接触体４，５となる導電性ゴムとして、体積固有抵抗率１．７Ω・ｃｍ、厚さ２ｍｍのものを使用したが、絶縁軸受に要求される抵抗値は１ＭΩ以上であるから、１．７Ω・ｃｍといった高い導電性は、皮膜接触体４，５に必ずしも必要ではない。図１において、皮膜接触体４の鍔部２ａの内面の部分４ａと絶縁皮膜３２ａの表面との接触面積をＳ１、蓋部材３の内面の皮膜接触体４と絶縁皮膜３２ａの表面との接触面積をＳ２、皮膜接触体４の治具本体２内径面の部分４ｂと絶縁皮膜３２ａの表面との接触面積をＳ３とした場合に、それぞれの接触面積での抵抗値は以下の式で表すことができる。
Ｓ１の抵抗Ｒ１＝ρ×（Ｔ／Ｓ１）
Ｓ２の抵抗Ｒ２＝ρ×（Ｔ／Ｓ２）
Ｓ３の抵抗Ｒ３＝ρ／（２×π×Ｂ）×ｌｎ（（Ｄ＋２×Ｔ）／Ｄ）
但し、
ρ：体積固有抵抗率
Ｔ：絶縁皮膜３２ａの厚さ
Ｂ：軸方向接触幅
Ｄ：絶縁皮膜３２ａと外輪母材３２ｂとの境界の直径寸法
【００２４】
軸受全体の抵抗値Ｒは、１／Ｒ＝１／Ｒ１＋１／Ｒ２＋１／Ｒ３の関係にあって、この場合の抵抗値を１ＭΩ以上に管理できれば良い。上式に皮膜接触体４，５の厚さを代入した場合、皮膜接触体４，５の抵抗値が測定誤差などの安全率を考慮した場合でも、１０ＫΩ以下になる体積固有抵抗率を有する皮膜接触体４，５であれば良い。皮膜接触体４，５の体積固有抵抗率が低ければ低い程、求めようとする絶縁抵抗測定値の誤差を小さくできることは言うまでもない。
【００２５】
また、皮膜接触体４，５はその硬度が低い程、絶縁皮膜３２ａの表面の凹凸に追随して接触し易くなるが、その硬度を必要以上に低くした場合、絶縁抵抗測定治具１をボルト締めするときの皮膜接触体４，５と絶縁皮膜３２ａとの間の締め代をそれだけ大きい側に設定しないと、皮膜接触体４，５と絶縁皮膜３２ａとが全面接触にならなくなる。逆に、皮膜接触体４，５の硬度が高すぎると、絶縁抵抗測定治具１をボルト締めするときの皮膜接触体４，５の絶縁皮膜３２ａの表面への追随性が低下したり、絶縁皮膜３２ａの表面の凹凸に対する皮膜接触体４，５の実接触率が低下したりする。これらのことから、皮膜接触体４，５の硬度は、ＨＳ５５〜ＨＳ９０程度が良く、さらにボルト締めの作業性の観点からはＨＳ７０±１０程度が好ましい。
【００２６】
図４は、この発明の他の実施形態を示す。この絶縁軸受の絶縁抵抗測定治具１Ａは、図１に示した第１の実施形態の絶縁抵抗測定治具１において、治具本体２および蓋部材３を、皮膜接触体４，５と同じ導電性高分子で構成することで、治具本体２および蓋部材３を、それ自体が皮膜接触体となるものとし、別部材の皮膜接触体４，５を省略したものである。治具の内径および内幅寸法は、第１の実施形態における皮膜接触体４，５の内径および内幅寸法とされる。その他の構成、および絶縁軸受３０の絶縁測定値を測定するときの態様は第１の実施形態の場合と同じである。
【００２７】
この実施形態の絶縁抵抗測定治具１Ａでは、これを構成する治具本体２および蓋部材３自体が導電性ゴムや導電性プラスチックなどの導電性高分子からなるので、絶縁抵抗測定治具１Ａをボルト１０，１１で締め付けて絶縁軸受３０を組み込む際に、絶縁皮膜３２ａの表面と絶縁抵抗測定治具１Ａの内面との間に生じる微小滑りに対して、絶縁抵抗測定治具１Ａの内面がその弾性変形により絶縁皮膜３２ａの表面に良く追従して接触でき、高い接触率が得られる。そのため、上記微小滑りに起因して絶縁抵抗測定治具１Ａおよび絶縁皮膜３２ａが摩耗することなく、絶縁抵抗値を正確に測定できる。また、治具本体２および蓋部材３が皮膜接触体で構成されるため、図１の実施形態のように別体の治具本体２および蓋部材３に皮膜接触体４，５を取付けるものに比べて構成が簡単である。
【００２８】
図５は、この発明のさらに他の実施形態を示す。この絶縁軸受の絶縁抵抗測定治具１Ｂは、絶縁軸受３０の外輪３２の幅面に接触するリング状の皮膜接触体１６からなる。皮膜接触体１６の材料が導電性高分子であることは第１の実施形態の場合と同様である。
【００２９】
この絶縁抵抗測定治具１Ｂによる絶縁軸受３０の絶縁抵抗値測定では、上記皮膜接触体１６を外輪３２の幅面、つまり絶縁皮膜３２ａの一方の幅面部分３２ａｂに接触させた状態で、抵抗計６のアース端子およびライン端子を、皮膜接触体１６および外輪３２の母材３２ｂに接続して、皮膜接触体１６と外輪母材３２ｂとの間の絶縁抵抗値を測定する。
この実施形態の絶縁軸受の絶縁抵抗測定治具１Ｂによっても、皮膜接触体１６が弾性変形により外輪絶縁皮膜３２ａの幅面部分３２ａｂに良く追従して接触するので、両部材間の実接触率が高くなり、絶縁抵抗値を正確に測定できる。
【００３０】
図６は、この発明のさらに他の実施形態を示す。この絶縁軸受の絶縁抵抗測定治具１Ｃは、図６（Ａ）のように絶縁軸受３０の外輪３２の外径面に弾性的に被せられるリング状の皮膜接触体１７からなる。皮膜接触体１７の材料が導電性高分子であることは第１の実施形態の場合と同様である。
【００３１】
この絶縁抵抗測定治具１Ｃによる絶縁軸受３０の絶縁抵抗値測定では、図６（Ｂ）のように上記皮膜接触体１７を外輪３２の外径面、つまり絶縁皮膜３２ａの外径面３２ａａに被せた状態で、抵抗計６のアース端子およびライン端子を、皮膜接触状態１７および外輪３２の母材３２ｂに接続して、皮膜接触状態１７と外輪母材３２ｂの間の絶縁抵抗値を測定する。
この実施形態の絶縁軸受の絶縁抵抗測定治具１Ｃによっても、皮膜接触体１７が弾性変形により外輪絶縁皮膜３２ａの外径部分３２ａａに良く追従して接触するので、両部材間の実接触率が高くなり、絶縁抵抗値を正確に測定できる。
【００３２】
図７は、この発明のさらに他の実施形態を示す。この絶縁軸受の絶縁抵抗測定治具１Ｄは、絶縁軸受３０の外輪３２の円周方向の一部が進入可能な凹部２０ａを有する治具本体２０と、この治具本体２０の凹部２０ａの開口に平面的に張られて上記外輪３２を接触させる膜状の皮膜接触体２１とでなる。皮膜接触体２１の材料が導電性高分子であることは第１の実施形態の場合と同様である。
【００３３】
この絶縁抵抗測定治具１Ｄによる絶縁軸受３０の絶縁抵抗値測定では、上記皮膜接触体２１を絶縁軸受３０の外輪３２の円周方向の一部、つまり外輪絶縁皮膜３２ａの外径部分３２ａａの一部に接触させた状態で、抵抗計６のアース端子およびライン端子を、皮膜接触体２１および外輪３２の母材３２ｂに接続して、皮膜接触体２１と外輪母材３２ｂの間の絶縁抵抗値を測定する。
この実施形態の絶縁軸受の絶縁抵抗測定治具１Ｄによっても、皮膜接触体２１が弾性変形により外輪絶縁皮膜３２ａの外径部分３２ａａに良く追従して接触するので、両部材間の実接触率が高くなり、絶縁抵抗値を正確に測定することができる。
【００３４】
【発明の効果】
この発明の絶縁軸受の絶縁抵抗測定治具は、外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する治具であって、上記絶縁軸受の外輪の絶縁皮膜に接触して抵抗計と接続される皮膜接触体が導電性高分子からなるものとしたため、軸受外輪の絶縁皮膜とこれに接触して抵抗計と接続される皮膜接触体との優れた接触率が得られて、絶縁軸受の絶縁抵抗値を正確に測定することができる。
この発明の絶縁軸受の絶縁抵抗測定方法は、外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する絶縁抵抗測定方法であって、導電性高分子からなる皮膜接触体を上記絶縁軸受の外輪の絶縁皮膜に接触させ、この皮膜接触体と上記外輪の絶縁皮膜で覆われていない部分との間に抵抗計を接続して上記絶縁軸受の絶縁抵抗値を測定する方法としたため、軸受外輪の絶縁皮膜とこれに接触して抵抗計と接続される皮膜接触体との優れた接触率が得られて、絶縁軸受の絶縁抵抗値を正確に測定することができる。
【図面の簡単な説明】
【図１】（Ａ）はこの発明の第１の実施形態にかかる絶縁軸受の絶縁抵抗測定治具の断面図、（Ｂ）は同絶縁抵抗測定治具の蓋部材を取り除いた状態を示す正面図である。
【図２】同絶縁抵抗測定治具で測定される絶縁軸受の一例を示す要部断面図である。
【図３】同絶縁抵抗測定治具による絶縁抵抗値測定の説明図である。
【図４】この発明の他の実施形態にかかる絶縁軸受の絶縁抵抗測定治具による絶縁抵抗値測定の説明図である。
【図５】この発明のさらに他の実施形態にかかる絶縁軸受の絶縁抵抗測定治具による絶縁抵抗値測定の説明図である。
【図６】（Ａ）はこの発明のさらに他の実施形態にかかる絶縁抵抗測定治具を絶縁軸受に取付けた状態を示す正面図、（Ｂ）は同絶縁抵抗測定治具による絶縁抵抗値測定の説明図である。
【図７】この発明のさらに他の実施形態にかかる絶縁軸受の絶縁抵抗測定治具による絶縁抵抗値測定の説明図である。
【図８】（Ａ）は従来例の断面図、（Ｂ）はその従来例における蓋部材を取り除いた状態を示す正面図である。
【図９】その従来例による絶縁抵抗値測定の説明図である。
【符号の説明】
１，１Ａ〜１Ｄ…絶縁抵抗測定治具
２…治具本体
２ａ…鍔部
３…蓋部材
４，５…皮膜接触体
６…抵抗計
１６…皮膜接触体
１７…皮膜接触体
２０…治具本体
２０ａ…凹部
２１…皮膜接触体
３０…絶縁軸受
３２…外輪
３２ａ…絶縁皮膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulation resistance measuring jig and a measuring method for measuring an insulation resistance of an insulating bearing used for a railway vehicle main motor, a generator, a general-purpose motor, and the like.
[0002]
[Prior art]
For bearings used in places where a large potential difference occurs between the housing and the shaft, such as an electric motor, an insulated bearing is used in which the outer diameter surface and the width surface of the outer ring are covered with an insulating film in order to prevent electrolytic corrosion. ing. Resins and ceramics are used for the insulating film. As this type of insulating bearing, there is one in which a metal film is formed on the outer layer of an insulating film.
When measuring the insulation performance of an insulated bearing having such a metal film, connect the earth side terminal and line side terminal of the resistance meter to the metal layer of the outer ring outermost layer and the outer ring base material. A metal layer can be used as an electrode, and the insulation resistance value of the entire outer insulating film is measured.
On the other hand, in an insulating bearing having an insulating film exposed on the surface, only a local insulation resistance value of the insulating film can be measured only by bringing a terminal into contact with a part of the insulating film.
In order to measure the entire insulation resistance value, a housing 42 that is in contact with the outer ring outer diameter surface and a lid member 43 that is in contact with the width surface as shown in FIGS. 8 and 9 were used as jigs. It is necessary to measure in the state. Conventionally, in order to perform measurement easily, the housing 42 is divided into two parts, tightened with bolts at a 180 ° position, and the lid member 43 is attached from the side surface. Both terminals of the ohmmeter 6 are connected to the housing 42 and the outer ring base material 32b. When such a jig is used, it is not necessary to press-fit or pull out the bearing unit 30 from the housing 42, and the insulation resistance value can be measured only by hand without using a press machine or the like. 8A is a cross-sectional view corresponding to the cross-sectional view taken along the line VIII-VIII in FIG. 8B.
[0003]
[Problems to be solved by the invention]
In the case of an insulating bearing having a one-layer structure made of ceramics with an insulating coating sprayed, jigs as shown in FIGS. 8 and 9 are used. However, in this case, there are the following problems. When used as an insulating bearing, the surface of the insulating coating 32a is finished to a normal size and roughness by polishing, but the split housing 42 is bolted even if it is finished to a normal size and roughness. Occasionally, a slight slip occurs at the contact portion between the inner surface of the housing and the insulating coating 32a. However, since the insulating coating 32a made of ceramic has higher hardness than the metal material of the housing 42, the housing 42 is slightly worn. The phenomenon to be seen is seen. Due to this wear, the inner diameter of the housing 42 changes with repeated use, and if the tightening allowance with the insulating coating 32a cannot be maintained, contact failure occurs and an accurate insulation resistance value cannot be measured. In addition, since the wear powder sticks to the surface of the insulating coating, there is a problem that it takes a lot of time for cleaning. Even when the lid member 43 is attached, the same phenomenon as in the case of the housing 42 occurs unless a careful tightening operation is performed. In the above description, problems have been described when the surface of the insulating coating 32a is polished. In practice, however, an insulation resistance test may be performed even before the polishing process. This inspection should be carried out so as to confirm that the insulation is defective due to defective spraying or the like before polishing, and not to polish the defective product, but the surface of the insulation coating 32a that has not been polished is In general, the surface is rough, and the contact rate between the housing 42 and the insulating coating 32a is low, and there is a problem that accurate measurement cannot be performed.
When the outer ring insulating coating 32a is made of resin, both the housing 42 and the insulating coating 32a are not worn even when the above slip occurs when measured using the jig. This is because the insulating coating 32a is made of resin and therefore has elasticity so that it can follow a minute slip.
[0004]
An object of the present invention is to provide an insulation resistance measuring process capable of accurately measuring the insulation resistance value of an insulated bearing by obtaining an excellent contact ratio between the insulation film of the bearing outer ring and the film contact body in contact with the insulation film. And providing an insulation resistance measuring method.
[0005]
[Means for Solving the Problems]
An insulation resistance measuring jig for an insulated bearing according to the present invention is a jig for measuring an insulation resistance value of an insulated bearing having an insulating film on an outer ring, and is connected to an ohmmeter in contact with the insulating film of the outer ring of the insulating bearing. The film contact body to be formed is made of a conductive polymer. The conductive polymer is conductive rubber, conductive plastic, or the like.
According to this configuration, since the film contact body is made of a conductive polymer, the film contact body easily adapts to unevenness due to the surface roughness of the insulating film due to its elastic deformation, and does not make local contact with the unevenness. Excellent contact rate can be obtained. Therefore, an accurate insulation resistance value can be measured. In particular, when the insulating coating is a ceramic sprayed layer and is in the state of the sprayed surface, it is generally rough compared to the polished surface, and the coating contact body has a low contact rate and is difficult to measure with a metal material. However, even with an insulating film composed of such a ceramic sprayed layer, if a coating contact body made of a conductive polymer is used, a high contact ratio can be obtained and an accurate insulation resistance value can be measured. Further, since the film contact body can be elastically deformed, even if a slight slip occurs when the film contact body is pressed against the insulating film, wear is prevented by elastic deformation.
As the film contact body, among conductive polymers, a conductive rubber excellent in elasticity is preferable because it easily conforms to the unevenness of the insulating film, but even a conductive plastic has a certain degree of elasticity. Compared with the case where the body is made of a metal material, the contact property is improved.
[0006]
In this invention, an insulation resistance measuring jig includes a ring-shaped jig body divided into two parts having a flange that fits the outer ring of an insulating bearing on the inner periphery and faces one width surface of the outer ring, and the jig. A lid member that is detachably attached to the tool body and faces the other width surface of the outer ring, an inner surface of the jig body, an inner surface of the flange, and an inner surface of the lid member to insulate the outer ring It is good also as what has a film contact body which contacts a film and is connected with the above-mentioned resistance meter.
In the case of this configuration, the film contact body can be brought into contact with substantially the entire insulating film extending from the outer diameter surface to the width surface of the outer ring, and more accurate measurement can be performed. Moreover, since the jig body is in the form of a ring split into two, it is easy to put in and out the insulated bearing to and from the jig. When such a split jig body is used, when the jig bodies on both sides are fastened to each other, a slight slip occurs between the insulating film surface and the inner surface of the jig body. On the other hand, since the film contact body is a conductive polymer, it can be followed by its elasticity. Therefore, the insulation resistance value can be measured without causing wear on both the jig and the insulating film.
[0007]
In this invention, the film contact body has a split ring-shaped jig body having a flange portion that fits the outer ring of the insulating bearing on the inner periphery and contacts one of the width surfaces of the outer ring, and the jig body. It is good also as what consists of a cover member attached to the other ring surface so that attachment or detachment is possible, and contacting the other width surface of the said outer ring | wheel.
In the case of this configuration, since the jig body is composed of a film contact body, the structure is simpler than that in which the film contact body is attached to a separate jig body. Also in this configuration, the film contact body can be brought into contact with substantially the entire insulating film extending from the outer diameter surface to the width surface of the outer ring, so that highly accurate measurement can be performed. Moreover, since the jig body is in the form of a ring split into two, it is easy to put in and out the insulated bearing to and from the jig. When the jig bodies on both sides divided into two are fastened to each other, a minute slip occurs between the insulating film surface and the inner surface of the jig body in the same manner as described above. Since the film contact body is a conductive polymer, it can be followed by its elasticity. Therefore, the insulation resistance value can be measured without causing wear on both the jig and the insulating film.
[0008]
In this invention, the said film contact body may be a ring-shaped member which contacts the width | variety surface of the outer ring | wheel of the said insulated bearing.
In this configuration, the film contact body is measured by contacting only the insulating film on the width surface of the outer ring, but the film contact body becomes familiar with the irregularities on the surface of the insulating film due to elastic deformation, and a high contact rate is obtained. Further, since the contact is made over the entire circumference, the insulation resistance can be measured with high accuracy. Moreover, since it is an insulation resistance measuring jig formed of a single ring-shaped film contact body, the configuration becomes very simple.
[0009]
In the present invention, the film contact body may be a ring-shaped member that elastically covers the outer diameter surface of the outer ring of the insulated bearing.
In this configuration, the film contact body is measured only by contacting the insulating film on the outer diameter surface of the outer ring, but the film contact body becomes familiar with the irregularities on the surface of the insulating film due to elastic deformation, and a high contact rate is obtained. In addition, since the contact is made over the entire circumference, the insulation resistance can be measured with high accuracy. Since this is an insulation resistance measuring jig consisting of a single ring-shaped film contact body that is elastically covered on the outer diameter surface of the outer ring, the configuration is very simple in this case as well.
[0010]
In this invention, a jig main body having a recess into which a part of the outer ring of the insulating bearing can enter in a circumferential direction, and a film that is stretched in a plane to the opening of the recess of the jig main body and makes contact with the outer ring It is good also as what consists of a film-like film contact body.
In this configuration, the outer ring is pressed against the planarly contacted film contact body, whereby the film contact body is elastically deformed along the outer ring outer diameter surface and comes into contact with the insulating film on the outer ring outer diameter surface. . In this case, the insulation resistance is measured in a part of the insulating film in the circumferential direction, and in that part, a high contact rate between the film contact body and the insulating film can be obtained, and the insulation resistance value can be measured with high accuracy.
[0011]
An insulation resistance measuring method for an insulated bearing according to the present invention is an insulation resistance measuring method for measuring an insulation resistance value of an insulated bearing having an insulation film on an outer ring, wherein a film contact made of a conductive polymer is used as the outer ring of the insulation bearing. This is a method of measuring the insulation resistance value of the insulated bearing by contacting the insulation film and connecting a resistance meter between the film contact body and the portion of the outer ring not covered with the insulation film.
According to this configuration, since the film contact body is made of a conductive polymer, the film contact body easily adapts to unevenness due to the surface roughness of the insulating film due to its elastic deformation, and does not make local contact with the unevenness. Excellent contact rate can be obtained. Therefore, an accurate insulation resistance value can be measured. In addition, since the film contact body can be elastically deformed, even if a slight slip occurs when the film contact body is pressed against the insulating film, the elastic deformation prevents wear.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. 1 shows an independent state of the insulation resistance measurement jig, FIG. 2 shows an insulation bearing to be measured, and FIG. 3 shows a state in which the insulation bearing is incorporated in the insulation resistance measurement jig. As shown in FIG. 2, the insulating bearing 30 to be measured has an insulating film 32 a on the outer ring 32. This insulating bearing 30 is a rolling bearing in which a plurality of rolling elements 33 made of balls are interposed between an inner ring 31 and an outer ring 32, and has a single layer structure from the outer diameter surface of the outer ring 32 to both width surfaces. An insulating film 32a is formed. As a result, a shaft (not shown) into which the inner ring 31 is fitted and a housing (not shown) that supports the outer ring 32 are electrically insulated and separated. The insulating film 32 a is a ceramic film, and is formed by spraying ceramics on the surface of the base material 32 b of the outer ring 32. The insulating film 32a may be made of resin.
[0013]
As shown in FIG. 1, the insulation resistance measuring jig 1 includes a jig body 2, a lid member 3, and film contact bodies 4 and 5. The jig body 2 has a ring-shaped ring shape that fits the outer ring 32 of the insulating bearing 30 on the inner circumference, and has a flange 2 a that faces one of the width surfaces of the outer ring 32. The lid member 3 is a ring-shaped member that is detachably attached to the jig body 2 and faces the other width surface of the outer ring 32. The film contact bodies 4 and 5 are provided on the inner peripheral surface of the jig body 2, the inner surface of the flange portion 2 a, and the inner surface of the lid member 3, respectively, and come into contact with the insulating film 32 a of the outer ring 32 of the insulating bearing 30. . An ohmmeter 6 (FIG. 3) is connected between the film contact bodies 4, 5 and the base material 32 b of the outer ring 32.
The material of the film contact bodies 4 and 5 is a conductive polymer such as conductive rubber or conductive plastic, and here, conductive rubber is used. As the conductive rubber to be the film contact bodies 4 and 5, a rubber having a volume resistivity of 1.7 Ω · cm and a thickness of 2 mm is used. The conductive rubber is manufactured by mixing a conductive material such as carbon powder or carbon fiber into a nitrile-based, acrylic-based, fluorine-based, or silicon-based rubber material in the manufacturing process. The shape of the conductive material to be mixed does not necessarily have to be powdery or fibrous. For example, it is sufficient if predetermined hardness and volume resistivity described later are obtained after rubber vulcanization molding.
[0014]
The jig body 2 is composed of two metal divided bodies 2A and 2B having a C-shaped front shape. At both ends of each of the divided main bodies 2A and 2B, mounting pieces 2b for connecting the divided main bodies 2A and 2B to each other by bolting and projecting to the outer diameter side are provided. Bolt insertion holes 7 are provided in both attachment pieces 2b of one divided main body 2A, and screw holes 8 that are aligned with the bolt insertion holes 7 are provided in both attachment pieces 2b of the other divided main body 2B. Both the split main bodies 2A and 2B are bolted by screwing the bolts 10 inserted through the bolt insertion holes 7 into the corresponding screw holes 8 to form the ring-shaped jig main body 2. Screw holes 9 for bolting the lid member 3 are provided at a plurality of locations on the side surface opposite to the side surface having the flange portion 2a of the jig body 2. The lid member 3 that is bolted to the side surface is provided with a plurality of bolt insertion holes (not shown) aligned with the screw holes 9. By screwing the bolts 11 inserted through these bolt insertion holes into the corresponding screw holes 9, a lid is placed on the side opposite to the flange 2a side of the jig body 2 as shown in FIG. The member 3 is bolted. 1A is a cross-sectional view corresponding to the cross-sectional view taken along the arrow I-I in FIG.
[0015]
Both the split main bodies 2A and 2B constituting the jig main body 2 are bolted so that the mating surfaces 12 and 13 (FIG. 1B) of the split main bodies 2A and 2B are in full contact with each other, and the film contact body 4 The inner diameter dimension D1 is processed to be slightly smaller than the outer diameter dimension of the outer ring insulating film 32a of the insulating bearing 30 incorporated in the insulation resistance measuring jig 1. In addition, in a state where the mating surfaces 14 and 15 (FIG. 1A) of the jig body 2 and the lid member 3 are in contact with each other, the inner surface portion 4a of the flange portion 2a of the film contact body 4 on the jig body 2 side The dimension W between the film contact bodies 5 on the lid member 3 side is processed so as to be slightly smaller than the width dimension of the insulating bearing 30 incorporated in the insulation resistance measuring jig 1. By being processed in this way, both the split main bodies 2A and 2B are bolted to form the jig main body 2, and the lid member 3 is bolted to the jig main body 2 to be placed in the insulation resistance measuring jig 1. By incorporating the insulating bearing 1, the coating contact bodies 4, 5 and the insulating coating 32 a of the outer ring 32 come into contact with each other with a predetermined allowance.
[0016]
As shown in FIG. 3, in the state in which the insulating bearing 30 is incorporated in the insulation resistance measuring jig 1, the entire surface of the insulating film 32 a of the bearing outer ring 32 is coated with the film contacts 4 and 5 of the jig body 2 and the lid member 3. To touch. In this state, the ground terminal of the resistance meter 6 is connected to the outer surface of the insulation resistance measuring jig 1, and the line terminal is connected to the base material 32b of the outer ring 32, so that the insulation resistance measuring jig 1 and the base material 32b of the outer ring 32 are connected. Measure the insulation resistance value between.
[0017]
When the insulation resistance measuring jig 1 of this embodiment is used, the film contact bodies 4 and 5 made of conductive rubber contact the surface of the outer ring insulating film 32a of the insulating bearing 30. When the insulating bearing 30 is assembled by tightening at 11, the coating contacts 4, 5 are elastically deformed by the coating contacts 4, 5 against the minute slip generated between the surface of the insulating coating 32 a and the inner surface of the insulation resistance measuring jig 1. It can follow the surface of 32a well and can contact. Therefore, the insulation resistance measurement jig 1 and the insulation film 32a are not worn due to the minute slip, and the insulation resistance value can be measured accurately. In particular, when the insulating film 32a is made of ceramics by thermal spraying, the surface thereof is rough, but the film contact bodies 4 and 5 made of conductive rubber are formed on the uneven portions on the surface of the ceramic insulating film 32a by elastic deformation. Since it follows easily, the contact rate of the film contact bodies 4 and 5 and the insulating film 32a becomes high, and an accurate insulation resistance value can be measured.
[0018]
The insulation resistance measuring jig 1 includes a split ring-shaped jig body 2 provided with a film contact body 4 and a lid member 3 provided with a film contact body 5. Since the insulation resistance value of the insulation bearing 30 is measured in a state where the insulation bearing 30 is incorporated in the tool 1, the insulation resistance value can be measured by contacting the entire surface from the outer diameter surface to the width surface of the outer ring insulation film 32a, and the accuracy is improved. Measurement is possible.
[0019]
In order to confirm the performance of the insulation resistance measuring jig 1 of this embodiment, the same insulation bearing 30 is used in the case of the above measurement system and the measurement system using the conventional insulation resistance measurement jig 41 shown in FIGS. The electrical characteristics of were compared. The results are shown in Table 1 below.
[0020]
[Table 1]
Figure 2005017251
[0021]
Table 1 shows the current value (A) flowing through the insulating bearing 30 when a voltage of 500 V is applied between the surface of the insulation resistance measuring jigs 1 and 41 and the outer ring base material 32b in each measurement system. The comparison result is shown. According to the results of Table 1, the current value in the embodiment using the film contact bodies 4 and 5 is higher than that in the conventional example. Since the insulation resistance value theoretically decreases as the surface area of the insulation film 32a increases, the results in Table 1 show that the actual contact area between the insulation resistance measuring jigs 1 and 41 and the insulation film 32a is the film contact body 4 , 5 is larger in this embodiment, indicating that the insulation resistance value can be measured more accurately.
[0022]
In addition, in order to confirm the influence on the insulation resistance value of the film contact bodies 4 and 5 themselves in this embodiment, an insulating film is formed on the surface of the outer ring, and a metal layer (conductor) is further formed on the surface. The insulation resistance measurement jig 1 of this embodiment and the insulation resistance measurement jig 41 of the conventional example shown in FIGS. 8 and 9 were subjected to a test for measuring the insulation resistance value. In this test result, both the embodiment and the conventional example were 50 MΩ (when 500 V was applied), and the influence of the coating contact bodies 4 and 5 was not recognized. In this test, since the outermost layer of the bearing outer ring is a conductor, there is almost no influence on the resistance value due to the actual contact ratio between the bearing outer ring and the insulation resistance measuring jig.
[0023]
In this embodiment, the conductive rubber used as the coating contact bodies 4 and 5 is one having a volume resistivity of 1.7 Ω · cm and a thickness of 2 mm, but the resistance value required for the insulated bearing is 1 MΩ or more. Therefore, high conductivity such as 1.7 Ω · cm is not necessarily required for the coating contact bodies 4 and 5. In FIG. 1, the contact area between the inner surface portion 4a of the flange 2a of the film contact body 4 and the surface of the insulating film 32a is S1, and the contact area between the film contact body 4 on the inner surface of the lid member 3 and the surface of the insulating film 32a. Where S3 is the contact area between the portion 4b of the inner surface of the jig body 2 of the film contact body 4 and the surface of the insulating film 32a, the resistance value at each contact area can be expressed by the following equation. it can.
S1 resistance R1 = ρ × (T / S1)
S2 resistance R2 = ρ × (T / S2)
S3 resistance R3 = ρ / (2 × π × B) × ln ((D + 2 × T) / D)
However,
ρ: Volume resistivity
T: thickness of the insulating film 32a
B: Axial contact width
D: Diameter dimension of the boundary between the insulating coating 32a and the outer ring base material 32b
[0024]
The resistance value R of the entire bearing has a relationship of 1 / R = 1 / R1 + 1 / R2 + 1 / R3, and the resistance value in this case may be managed to be 1 MΩ or more. When the thickness of the film contact bodies 4 and 5 is substituted into the above equation, the film having a volume resistivity of 10 KΩ or less even when the resistance value of the film contact bodies 4 and 5 takes into account the safety factor such as measurement error The contact bodies 4 and 5 may be used. It goes without saying that the lower the volume resistivity of the film contact bodies 4 and 5, the smaller the error of the measured insulation resistance value to be obtained.
[0025]
In addition, the lower the hardness of the film contact bodies 4 and 5, the easier it is to follow the surface irregularities of the insulating film 32a, but when the hardness is made lower than necessary, the insulation resistance measuring jig 1 is bolted. Unless the tightening allowance between the film contact bodies 4 and 5 and the insulating film 32a when tightening is set to the larger side, the film contact bodies 4 and 5 and the insulating film 32a will not be in full contact. On the other hand, if the hardness of the film contact bodies 4 and 5 is too high, the followability of the film contact bodies 4 and 5 to the surface of the insulating film 32a when bolting the insulation resistance measuring jig 1 is reduced, or the insulation is reduced. The actual contact rate of the film contact bodies 4 and 5 with respect to the irregularities on the surface of the film 32a may decrease. From these facts, the hardness of the film contact bodies 4 and 5 is preferably about HS55 to HS90, and more preferably about HS70 ± 10 from the viewpoint of bolting workability.
[0026]
FIG. 4 shows another embodiment of the present invention. The insulation resistance measuring jig 1A of the insulated bearing is the same as the film contact bodies 4 and 5 in the jig body 2 and the lid member 3 in the insulation resistance measuring jig 1 of the first embodiment shown in FIG. By using the conductive polymer, the jig body 2 and the lid member 3 are themselves film contact bodies, and the separate film contact bodies 4 and 5 are omitted. The inner diameter and inner width dimension of the jig are the inner diameter and inner width dimension of the film contact bodies 4 and 5 in the first embodiment. Other configurations and aspects when measuring the insulation measurement value of the insulating bearing 30 are the same as those in the case of the first embodiment.
[0027]
In the insulation resistance measuring jig 1A of this embodiment, since the jig body 2 and the lid member 3 constituting the same are made of a conductive polymer such as conductive rubber or conductive plastic, the insulation resistance measuring jig 1A is When the insulating bearing 30 is assembled by tightening with the bolts 10 and 11, the inner surface of the insulation resistance measuring jig 1A is against the minute slip generated between the surface of the insulating film 32a and the inner surface of the insulation resistance measuring jig 1A. Due to the elastic deformation, the surface of the insulating film 32a can be well tracked and contacted, and a high contact rate can be obtained. Therefore, the insulation resistance value can be accurately measured without the insulation resistance measuring jig 1A and the insulation film 32a being worn due to the minute slip. In addition, since the jig body 2 and the lid member 3 are formed of a film contact body, the film contact bodies 4 and 5 are attached to the separate jig body 2 and the lid member 3 as in the embodiment of FIG. The configuration is simpler than that.
[0028]
FIG. 5 shows still another embodiment of the present invention. The insulation resistance measuring jig 1 </ b> B of the insulated bearing includes a ring-shaped film contact body 16 that contacts the width surface of the outer ring 32 of the insulated bearing 30. The material of the film contact body 16 is a conductive polymer as in the case of the first embodiment.
[0029]
In the measurement of the insulation resistance value of the insulation bearing 30 by the insulation resistance measurement jig 1B, the resistance meter 6 is in a state where the film contact body 16 is in contact with the width surface of the outer ring 32, that is, one width surface portion 32ab of the insulation film 32a. The ground terminal and the line terminal are connected to the film contact 16 and the base material 32b of the outer ring 32, and the insulation resistance value between the film contact 16 and the outer ring base material 32b is measured.
Also with the insulation resistance measuring jig 1B of the insulated bearing of this embodiment, the film contact body 16 follows the width surface portion 32ab of the outer ring insulating film 32a well by elastic deformation, so that the actual contact ratio between both members is high. Thus, the insulation resistance value can be measured accurately.
[0030]
FIG. 6 shows still another embodiment of the present invention. As shown in FIG. 6A, the insulation resistance measuring jig 1C of the insulated bearing is composed of a ring-shaped film contact body 17 that is elastically placed on the outer diameter surface of the outer ring 32 of the insulated bearing 30. The material of the film contact body 17 is a conductive polymer as in the case of the first embodiment.
[0031]
In the measurement of the insulation resistance value of the insulation bearing 30 using the insulation resistance measurement jig 1C, as shown in FIG. 6B, the film contact body 17 is put on the outer diameter surface of the outer ring 32, that is, the outer diameter surface 32aa of the insulation film 32a. In this state, the ground terminal and line terminal of the resistance meter 6 are connected to the film contact state 17 and the base material 32b of the outer ring 32, and the insulation resistance value between the film contact state 17 and the outer ring base material 32b is measured.
Also with the insulation resistance measuring jig 1C of the insulated bearing of this embodiment, the film contact body 17 follows the outer diameter portion 32aa of the outer ring insulating film 32a well by elastic deformation, so that the actual contact ratio between the two members is high. The insulation resistance value can be accurately measured.
[0032]
FIG. 7 shows still another embodiment of the present invention. The insulation resistance measuring jig 1D of the insulated bearing has a jig body 20 having a recess 20a into which a part of the outer ring 32 of the insulated bearing 30 can enter and an opening of the recess 20a of the jig body 20. A film-like film contact body 21 which is stretched in a plane and contacts the outer ring 32 is formed. The material of the film contact 21 is a conductive polymer as in the case of the first embodiment.
[0033]
In the measurement of the insulation resistance value of the insulation bearing 30 by the insulation resistance measurement jig 1D, the film contact body 21 is part of the circumferential direction of the outer ring 32 of the insulation bearing 30, that is, one of the outer diameter portions 32aa of the outer ring insulation film 32a. The ground terminal and the line terminal of the ohmmeter 6 are connected to the base material 32b of the film contact body 21 and the outer ring 32 in a state of being in contact with the portion, and the insulation resistance value between the film contact body 21 and the outer ring base material 32b Measure.
Even with the insulation resistance measuring jig 1D of the insulated bearing of this embodiment, the film contact body 21 follows the outer diameter portion 32aa of the outer ring insulating film 32a well by elastic deformation, so that the actual contact ratio between the two members is high. The insulation resistance value can be accurately measured.
[0034]
【The invention's effect】
An insulation resistance measuring jig for an insulated bearing according to the present invention is a jig for measuring an insulation resistance value of an insulated bearing having an insulating film on an outer ring, and is connected to an ohmmeter in contact with the insulating film of the outer ring of the insulating bearing. The film contact body to be formed is made of a conductive polymer, so that an excellent contact rate between the insulating film of the bearing outer ring and the film contact body that is in contact with the film and connected to the resistance meter is obtained. The insulation resistance value can be accurately measured.
An insulation resistance measuring method for an insulated bearing according to the present invention is an insulation resistance measuring method for measuring an insulation resistance value of an insulated bearing having an insulation film on an outer ring, wherein a film contact made of a conductive polymer is used as the outer ring of the insulation bearing. In this method, the resistance of the outer bearing is measured by connecting a resistance meter between the outer surface of the outer ring and the portion of the outer ring not covered with the insulating film. An excellent contact rate between the insulating film and the film contact body that is in contact with the insulating film and is connected to the resistance meter is obtained, and the insulation resistance value of the insulating bearing can be accurately measured.
[Brief description of the drawings]
1A is a cross-sectional view of an insulation resistance measuring jig for an insulated bearing according to a first embodiment of the present invention, and FIG. 1B is a front view showing a state where a lid member of the insulation resistance measuring jig is removed. FIG.
FIG. 2 is a cross-sectional view of an essential part showing an example of an insulated bearing measured by the insulation resistance measuring jig.
FIG. 3 is an explanatory diagram of insulation resistance value measurement by the insulation resistance measurement jig.
FIG. 4 is an explanatory view of insulation resistance value measurement by an insulation resistance measurement jig of an insulated bearing according to another embodiment of the present invention.
FIG. 5 is an explanatory diagram of insulation resistance value measurement by an insulation resistance measurement jig of an insulated bearing according to still another embodiment of the present invention.
6A is a front view showing a state in which an insulation resistance measurement jig according to still another embodiment of the present invention is attached to an insulation bearing, and FIG. 6B is an insulation resistance value measurement using the insulation resistance measurement jig. It is explanatory drawing of.
FIG. 7 is an explanatory diagram of insulation resistance value measurement by an insulation resistance measurement jig of an insulated bearing according to still another embodiment of the present invention.
8A is a cross-sectional view of a conventional example, and FIG. 8B is a front view showing a state in which the lid member in the conventional example is removed.
FIG. 9 is an explanatory view of insulation resistance value measurement according to the conventional example.
[Explanation of symbols]
1, 1A-1D ... Insulation resistance measurement jig
2 ... Jig body
2a ... Buttocks
3 ... Lid member
4, 5 ... Film contact
6 ... Resistance meter
16 ... Film contact
17 ... Film contact
20 ... Jig body
20a ... recess
21 ... Film contact
30 ... Insulated bearing
32 ... Outer ring
32a ... Insulating film

Claims (8)

外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する治具であって、上記絶縁軸受の外輪の絶縁皮膜に接触して抵抗計と接続される皮膜接触体が導電性高分子からなる絶縁軸受の絶縁抵抗測定治具。A jig for measuring an insulation resistance value of an insulating bearing having an insulating film on an outer ring, wherein the film contact body that is in contact with the insulating film of the outer ring of the insulating bearing and is connected to the resistance meter is made of a conductive polymer. Jig for measuring insulation resistance of bearings. 請求項１において、上記導電性高分子が導電性ゴムである絶縁軸受の絶縁抵抗測定治具。The insulation resistance measuring jig for an insulated bearing according to claim 1, wherein the conductive polymer is a conductive rubber. 請求項１または請求項２において、絶縁軸受の外輪を内周に嵌合させかつ上記外輪の片方の幅面に対向する鍔部を有する２つ割りのリング状の治具本体と、この治具本体に着脱可能に取付けられ上記外輪のもう片方の幅面に対向する蓋部材と、上記治具本体の内周面および鍔部の内面、並びに上記蓋部材の内面に設けられて上記外輪の絶縁皮膜に接触し上記抵抗計と接続される皮膜接触体とを有する絶縁軸受の絶縁抵抗測定治具。3. A split ring-shaped jig body having a flange that fits the outer ring of the insulating bearing on the inner periphery and faces one of the width surfaces of the outer ring, and the jig body A lid member that is detachably attached to the other width surface of the outer ring, an inner peripheral surface of the jig main body, an inner surface of the flange portion, and an inner surface of the lid member, and is provided on the insulating film of the outer ring. An insulation resistance measuring jig of an insulating bearing having a film contact body that contacts and is connected to the ohmmeter. 請求項１または請求項２において、皮膜接触体が、絶縁軸受の外輪を内周に嵌合させかつ上記外輪の片方の幅面に接触する鍔部を有する２つ割りのリング状の治具本体と、この治具本体に着脱可能に取付けられ上記外輪のもう片方の幅面に接触する蓋部材とでなる絶縁軸受の絶縁抵抗測定治具。The ring-shaped jig main body having a split ring structure according to claim 1 or 2, wherein the film contact body has a flange that fits the outer ring of the insulating bearing to the inner periphery and contacts one of the width surfaces of the outer ring. An insulation resistance measurement jig for an insulation bearing, which is detachably attached to the jig body and a lid member that contacts the other width surface of the outer ring. 請求項１または請求項２において、上記皮膜接触体が、上記絶縁軸受の外輪の幅面に接触するリング状の部材である絶縁軸受の絶縁抵抗測定治具。The insulation resistance measuring jig for an insulated bearing according to claim 1 or 2, wherein the film contact body is a ring-shaped member that contacts a width surface of the outer ring of the insulated bearing. 請求項１または請求項２において、上記皮膜接触体が、上記絶縁軸受の外輪の外径面に弾性的に被せられるリング状の部材である絶縁軸受の絶縁抵抗測定治具。The insulation resistance measuring jig for an insulated bearing according to claim 1 or 2, wherein the film contact body is a ring-shaped member that is elastically covered on an outer diameter surface of an outer ring of the insulated bearing. 請求項１または請求項２において、上記絶縁軸受の外輪の円周方向の一部が進入可能な凹部を有する治具本体と、この治具本体の上記凹部の開口に平面的に張られて上記外輪を接触させる膜状の皮膜接触体とでなる絶縁軸受の絶縁抵抗測定治具。3. The jig main body having a recess into which a part of the outer ring of the insulating bearing can be entered, and a planar extension of the opening of the recess of the jig main body. An insulation resistance measuring jig for an insulated bearing comprising a film-like film contact body for contacting an outer ring. 外輪に絶縁皮膜を有する絶縁軸受の絶縁抵抗値を測定する絶縁抵抗測定方法であって、導電性高分子からなる皮膜接触体を上記絶縁軸受の外輪の絶縁皮膜に接触させ、この皮膜接触体と上記外輪の絶縁皮膜で覆われていない部分との間に抵抗計を接続して上記絶縁軸受の絶縁抵抗値を測定する絶縁軸受の絶縁抵抗測定方法。An insulation resistance measurement method for measuring an insulation resistance value of an insulation bearing having an insulation film on an outer ring, wherein a film contact body made of a conductive polymer is brought into contact with the insulation film of the outer ring of the insulation bearing, and the film contact body and An insulation resistance measurement method for an insulated bearing, wherein an ohmmeter is connected between the outer ring and a portion not covered with an insulation film to measure an insulation resistance value of the insulated bearing.
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