JP2008286661A

JP2008286661A - Device and method for testing bearing

Info

Publication number: JP2008286661A
Application number: JP2007132472A
Authority: JP
Inventors: Takayuki Kawamura; 隆之川村; Eishin Mikami; 英信三上
Original assignee: NTN Corp; NTN Toyo Bearing Co Ltd
Current assignee: NTN Corp
Priority date: 2007-05-18
Filing date: 2007-05-18
Publication date: 2008-11-27

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for testing a bearing, capable of reproducing brittle separation caused by hydrogen brittleness, in a short time and with precision. <P>SOLUTION: A test bearing 2 and a dummy bearing 3 are mounted at an interval on a rotary axis 1 driven with a belt by a motor 5, to which a load is applied by a tension of an endless belt 7. The outer ring 2b of the test bearing 2 is fixed on the housing 4a via an outer ring supporting member 8 having low rigidity, and the outer ring 3b of the dummy bearing 3 is fixed directly on another housing 4b. The interval between contact terminals 9a, 9b mounted on each housing 4a, 4b is energized; and by making a current to flow between an inner ring 2a of the outer ring 2b via a ball 2c, hydrogen is generated forcibly by electrolysis and the like from grease enclosed in the test bearing 2, and generation of hydrogen is accelerated with increase in vibration or slipping in the test bearing 2, and thereby the brittle separation caused by hydrogen brittleness can be reproduced, in a short time and with precision. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、転がり軸受の耐久寿命を試験する軸受試験装置および軸受試験方法に関する。 The present invention relates to a bearing test apparatus and a bearing test method for testing the durability life of a rolling bearing.

転がり軸受の耐久寿命を試験する軸受試験装置としては、試験軸受の内輪を取り付ける回転軸と、試験軸受の外輪を固定するハウジングとを有し、回転軸を回転駆動する回転駆動手段と、試験軸受に荷重を負荷する荷重負荷手段とを設けたものが多く使用されている（例えば、特許文献１参照）。これらの軸受試験装置は、軸受の設計、開発、品質保証、トラブルの原因究明等に用いられている。 A bearing test apparatus for testing the endurance life of a rolling bearing includes a rotating shaft to which an inner ring of the test bearing is attached, a housing for fixing an outer ring of the test bearing, and a rotational driving means for rotationally driving the rotating shaft, and a test bearing. Many are provided with a load loading means for loading a load (see, for example, Patent Document 1). These bearing test apparatuses are used for bearing design, development, quality assurance, trouble investigation, and the like.

一方、自動車用補機であるオルタネータ等を支持する転がり軸受では、上述したような軸受試験装置で十分な耐久寿命が保証されたものであっても、早期に固定輪側の軌道面に脆性剥離が発生するものがあることが知られている。この脆性剥離の発生は、軸受に封入するグリースの種類によっても左右されることが知られている。 On the other hand, in rolling bearings that support alternators, etc., which are auxiliary equipment for automobiles, even if the bearing test equipment as described above guarantees a sufficient endurance life, brittle delamination is quickly caused on the raceway surface on the fixed ring side. Is known to occur. It is known that the occurrence of this brittle peeling depends on the type of grease enclosed in the bearing.

この脆性剥離の原因については種々の検討がなされているが、加減速を繰り返すサイクルで軸受試験後の軸受を水素分析した結果、固定輪で水素量が増加し、回転輪と転動体ではこのような水素量の増加が認められなかったことから、固定輪を形成する鋼の水素脆化によるものと推定されている（例えば、非特許文献１参照）。すなわち、転動体とのすべりによって軌道面に発生する新生面を触媒として、軸受に封入されたグリースが分解し、この分解で発生する水素が軌道面の鋼中に浸入して、水素脆化を引き起こすものと考えられている。 Various investigations have been made on the cause of this brittle peeling, but as a result of hydrogen analysis of the bearing after the bearing test in a cycle of repeated acceleration and deceleration, the amount of hydrogen increased in the fixed ring, and this was the case for the rotating wheel and rolling element. Since no significant increase in the amount of hydrogen was observed, it is presumed to be due to hydrogen embrittlement of the steel forming the stationary ring (see, for example, Non-Patent Document 1). That is, the grease encapsulated in the bearing is decomposed using the new surface generated on the raceway surface by sliding with the rolling element as a catalyst, and hydrogen generated by this decomposition penetrates into the steel of the raceway surface, causing hydrogen embrittlement. It is considered a thing.

このため、特許文献１に記載されたような従来の軸受試験装置では、上述したような脆性剥離を再現できず、この水素脆化に起因すると考えられる脆性剥離による軸受寿命の低下を評価できない問題があり、オルタネータ、テンションプーリ、アイドラプーリ、タイミングベルトプーリ、電磁クラッチ、コンプレッサ、ウォータポンプ等の自動車用補機に使用される軸受、クランクシャフト、カムシャフト等のエンジンに組み込まれる軸を支持する軸受、各種モータや工作機械の回転軸を支持する軸受等、このような脆性剥離が発生する恐れがある用途に使用される転がり軸受に対して、その設計、開発、品質保証等に有効に活用できる軸受試験装置が望まれていた。 For this reason, the conventional bearing test apparatus as described in Patent Document 1 cannot reproduce the brittle separation as described above, and cannot evaluate the decrease in bearing life due to the brittle separation considered to be caused by hydrogen embrittlement. Bearings used in alternators, tension pulleys, idler pulleys, timing belt pulleys, electromagnetic clutches, compressors, water pumps and other automotive auxiliary equipment, and bearings that support shafts such as crankshafts and camshafts It can be effectively used for the design, development, quality assurance, etc. of rolling bearings used in applications where there is a risk of brittle delamination, such as bearings that support the rotating shafts of various motors and machine tools. A bearing test device was desired.

このような要望に対して、本発明者らは、試験軸受の内輪と外輪との間に転動体を介して電流を流す通電手段を設けることにより、軸受に封入されるグリースから電気分解によって強制的に水素を発生させ、水素脆化に起因すると考えられる脆性剥離を再現可能とする軸受試験装置と軸受試験方法を先に提案している（特許文献２参照）。 In response to such a demand, the present inventors have forced electrolysis from the grease sealed in the bearing by providing a current-carrying means for passing a current through the rolling element between the inner ring and the outer ring of the test bearing. In the past, a bearing test apparatus and a bearing test method that can generate hydrogen and reproduce brittle delamination considered to be caused by hydrogen embrittlement have been proposed (see Patent Document 2).

特開平３−１２８４３０号公報（第２図）Japanese Patent Laid-Open No. 3-128430 (FIG. 2) 玉田、田中「外輪回転による脆性剥離の再現実験」（社）日本トライボロジー学会トライボロジー会議予稿集、１９９４年１０月、ｐ．７４９−７５２Tamada, Tanaka “Reproduction experiment of brittle debonding due to rotation of outer ring” Tribology Conference Proceedings of Japan Tribology Society, October 1994, p. 749-752 特開２００６−３１７２７３号公報JP 2006-317273 A

特許文献２に記載された軸受試験装置は、水素脆化に起因する脆性剥離を再現できるが、脆性剥離を短時間で再現するためには、軸受試験に流す電流を大きくする必要があるので、電食等の他の不具合によって先に軸受寿命が評価されることがあり、脆性剥離の再現試験装置として不十分な面があった。大きな電流による電食等の不具合が発生しないようにするためには、軸受試験に流す電流を小さくすればよいが、脆性剥離の再現に時間がかかる問題がある。 The bearing test apparatus described in Patent Document 2 can reproduce brittle peeling due to hydrogen embrittlement, but in order to reproduce brittle peeling in a short time, it is necessary to increase the current passed through the bearing test. The bearing life may be evaluated first due to other problems such as electrolytic corrosion, which is insufficient as a brittle peeling reproduction test apparatus. In order to prevent the occurrence of problems such as electrolytic corrosion due to a large current, the current passed through the bearing test may be reduced, but there is a problem that it takes time to reproduce brittle peeling.

そこで、本発明の課題は、水素脆化に起因する脆性剥離を短時間で的確に再現できる軸受試験装置と軸受試験方法を提供することである。 Accordingly, an object of the present invention is to provide a bearing test apparatus and a bearing test method capable of accurately reproducing brittle peeling due to hydrogen embrittlement in a short time.

上記の課題を解決するために、本発明の軸受試験装置は、内外輪および転動体が導電体で形成された試験軸受の内輪を取り付ける回転軸と、前記試験軸受の外輪を固定するハウジングとを有し、前記回転軸を回転駆動する回転駆動手段と、前記試験軸受に荷重を負荷する荷重負荷手段とを設けた軸受試験装置において、前記試験軸受の内輪と外輪との間に前記転動体を介して電流を流す通電手段を設け、前記試験軸受の外輪を剛性の低い外輪支持部材を介して前記ハウジングに固定した構成を採用した。 In order to solve the above-described problems, a bearing test apparatus according to the present invention includes a rotating shaft to which an inner ring of a test bearing in which inner and outer rings and rolling elements are formed of a conductor are attached, and a housing that fixes the outer ring of the test bearing. A bearing test apparatus provided with a rotation driving means for rotating the rotation shaft and a load loading means for applying a load to the test bearing, wherein the rolling element is disposed between an inner ring and an outer ring of the test bearing. A configuration is adopted in which an energizing means for supplying current is provided, and the outer ring of the test bearing is fixed to the housing via an outer ring support member having low rigidity.

すなわち、試験軸受の内輪と外輪との間に前記転動体を介して電流を流す通電手段を設けることにより、軸受に封入されるグリースから電気分解や、電食摩耗により生じた新生面の触媒作用によって強制的に水素を発生させるとともに、試験軸受の外輪を剛性の低い外輪支持部材を介してハウジングに固定することにより、試験軸受内の振動やすべりを大きくして水素の発生を促進させ、水素脆化に起因する脆性剥離を短時間で的確に再現できるようにした。 That is, by providing a current-carrying means for passing a current through the rolling elements between the inner ring and the outer ring of the test bearing, electrolysis from the grease sealed in the bearing and catalysis of the new surface caused by electrolytic corrosion wear By forcibly generating hydrogen and fixing the outer ring of the test bearing to the housing via a low-rigidity outer ring support member, vibration and slip in the test bearing are increased to promote hydrogen generation and hydrogen embrittlement. Brittle exfoliation caused by crystallization can be accurately reproduced in a short time.

前記通電手段を、前記回転軸を前記試験軸受と離れた位置で支持し、内外輪および転動体が導電体で形成されたダミー軸受を設け、このダミー軸受の外輪を、前記試験軸受の外輪を固定したハウジングと絶縁した別のハウジングに固定して、これらの試験軸受とダミー軸受の各ハウジングおよび前記回転軸を導電体で形成し、前記外輪支持部材を介在させた前記試験軸受の外輪とハウジング間を、外輪支持部材を導電体で形成するか、または外輪とハウジング間に接触部位を設けて導通させ、前記試験軸受とダミー軸受のハウジング間に通電するものとすることにより、スリップリング等の回転体用接点を用いずに、試験軸受の外輪と内輪の間に転動体を介して容易に電流を流すことができる。 The energizing means is provided with a dummy bearing in which the rotating shaft is supported at a position away from the test bearing, and inner and outer rings and rolling elements are formed of a conductor. The outer ring of the dummy bearing is the outer ring of the test bearing. An outer ring and a housing of the test bearing in which the housing of the test bearing and the dummy bearing and the rotating shaft are formed of a conductor and the outer ring support member is interposed. The outer ring support member is formed of a conductor, or a contact portion is provided between the outer ring and the housing so as to be electrically connected, and a current is passed between the test bearing and the housing of the dummy bearing. A current can be easily passed through the rolling element between the outer ring and the inner ring of the test bearing without using the contact for the rotating body.

前記回転駆動手段を、前記回転軸と平行にモータの出力軸を配設し、前記回転軸に試験軸受の取り付け部から延長された延長部を設けて、この回転軸の延長部と前記モータの出力軸とにプーリを取り付け、これらのプーリ間に無端ベルトを張り渡して、前記回転軸をベルト駆動するものとし、前記荷重負荷手段を、前記無端ベルトの張力で前記回転軸の延長部に荷重を負荷するものとすることにより、別途の荷重負荷手段を不要とし、軸受試験装置をシンプルな構成とすることができる。 The rotation drive means is provided with an output shaft of a motor parallel to the rotation shaft, and an extension portion extended from a mounting portion of a test bearing is provided on the rotation shaft. The extension portion of the rotation shaft and the motor A pulley is attached to the output shaft, an endless belt is stretched between these pulleys, and the rotary shaft is driven by a belt. The load loading means loads the extension portion of the rotary shaft with the tension of the endless belt. Therefore, a separate load loading means is not required, and the bearing test apparatus can have a simple configuration.

前記回転駆動手段を、加減速を繰り返す回転サイクルを付与できるものとすることにより、軸受の試験条件を実機での使用状態に近いものとすることができる。 By making the rotation driving means capable of providing a rotation cycle in which acceleration and deceleration are repeated, the bearing test conditions can be made close to the state of use in an actual machine.

前記荷重負荷手段によって前記試験軸受に負荷される動等価荷重Ｐと、試験軸受の基本動定格荷重Ｃとの比Ｐ／Ｃは、脆性剥離を発生させるために０．０５以上とするのが好ましい。なお、上述した脆性剥離が発生する恐れがある用途での転がり軸受の通常の使用条件下でのＰ／Ｃは０．２以下である。 The ratio P / C between the dynamic equivalent load P applied to the test bearing by the load loading means and the basic dynamic load rating C of the test bearing is preferably 0.05 or more in order to cause brittle peeling. . In addition, P / C under the normal use conditions of the rolling bearing in the use which may generate | occur | produce the brittle peeling mentioned above is 0.2 or less.

前記剛性の低い外輪支持部材は、縦弾性係数が１０×１０^４ＭＰａ以下の材料で形成することができる。縦弾性係数が１０×１０^４ＭＰａ以下の材料としては、アルミニウム、マグネシウム等の軽金属、これらの軽金属の合金、黄銅等の金属材料や各種樹脂材料を用いることができる。 The outer ring supporting member having low rigidity can be formed of a material having a longitudinal elastic modulus of 10 × 10 ⁴ MPa or less. As a material having a longitudinal elastic modulus of 10 × 10 ⁴ MPa or less, light metals such as aluminum and magnesium, alloys of these light metals, metal materials such as brass, and various resin materials can be used.

前記剛性の低い外輪支持部材は、中空の材料で形成することもできる。 The outer ring supporting member having low rigidity can be formed of a hollow material.

また、本発明の軸受試験方法は、内外輪および転動体が導電体で形成された試験軸受の内輪を回転軸に取り付け、前記試験軸受の外輪をハウジングに固定して、前記試験軸受に荷重を負荷しながら、前記回転軸を回転駆動する軸受試験方法において、前記試験軸受の外輪を剛性の低い外輪支持部材を介して前記ハウジングに固定し、前記試験軸受の内輪と外輪との間に前記転動体を介して電流を流しながら、前記回転軸を回転駆動する方法を採用することにより、軸受に封入されるグリースから電気分解や、電食摩耗により生じた新生面の触媒作用によって強制的に水素を発生させるとともに、試験軸受内の振動やすべりを大きくして水素の発生を促進させ、水素脆化に起因する脆性剥離を短時間で的確に再現できるようにした。 In the bearing test method of the present invention, an inner ring of a test bearing in which inner and outer rings and rolling elements are formed of a conductor are attached to a rotating shaft, the outer ring of the test bearing is fixed to a housing, and a load is applied to the test bearing. In the bearing test method in which the rotating shaft is rotationally driven while being loaded, the outer ring of the test bearing is fixed to the housing via an outer ring support member having low rigidity, and the rolling is performed between the inner ring and the outer ring of the test bearing. By adopting a method in which the rotating shaft is driven to rotate while passing an electric current through the moving body, hydrogen is forced to be generated from the grease sealed in the bearing by electrolysis or catalysis of the new surface caused by electrolytic corrosion. In addition to increasing the vibration and slip in the test bearing, the generation of hydrogen was promoted, so that brittle delamination caused by hydrogen embrittlement could be accurately reproduced in a short time.

本発明の軸受試験装置は、試験軸受の内輪と外輪との間に転動体を介して電流を流す通電手段を設け、試験軸受の外輪を剛性の低い外輪支持部材を介してハウジングに固定することにより、軸受に封入されるグリースから電気分解や、電食摩耗により生じた新生面の触媒作用によって強制的に水素を発生させるとともに、試験軸受内の振動やすべりを大きくして水素の発生を促進させるようにしたので、水素脆化に起因する脆性剥離を短時間で的確に再現でき、このような脆性剥離が発生する恐れのある用途に使用される転がり軸受の設計、開発、品質保証等に有効に活用することができる。 In the bearing test apparatus of the present invention, an energizing means for passing a current through a rolling element is provided between an inner ring and an outer ring of a test bearing, and the outer ring of the test bearing is fixed to a housing via an outer ring support member having low rigidity. To forcibly generate hydrogen from the grease sealed in the bearing by electrolysis or catalysis of the new surface caused by electrolytic corrosion, and increase the vibration and slip in the test bearing to promote hydrogen generation As a result, brittle delamination caused by hydrogen embrittlement can be accurately reproduced in a short time, and it is effective for the design, development, quality assurance, etc. of rolling bearings used in applications where such brittle delamination may occur. It can be used for.

前記通電手段を、回転軸を試験軸受と離れた位置で支持し、内外輪および転動体が導電体で形成されたダミー軸受を設け、このダミー軸受の外輪を、試験軸受の外輪を固定したハウジングと絶縁した別のハウジングに固定して、これらの試験軸受とダミー軸受の各ハウジングおよび回転軸を導電体で形成し、外輪支持部材を介在させた試験軸受の外輪とハウジング間を、外輪支持部材を導電体で形成するか、または外輪とハウジング間に接触部位を設けて導通させ、試験軸受とダミー軸受のハウジング間に通電するものとすることにより、スリップリング等の回転体用接点を用いずに、試験軸受の外輪と内輪の間に転動体を介して容易に電流を流すことができる。 A housing in which the current-carrying means is supported at a position where the rotating shaft is separated from the test bearing, a dummy bearing in which inner and outer rings and rolling elements are formed of a conductor is provided, and the outer ring of the dummy bearing is fixed to the outer ring of the test bearing The outer ring support member is fixed between the outer ring and the housing of the test bearing with the outer ring support member interposed therebetween. By using a conductive material, or by providing a contact portion between the outer ring and the housing so as to conduct electricity, and energizing the housing between the test bearing and the dummy bearing, without using a contact for a rotating body such as a slip ring. In addition, a current can be easily passed between the outer ring and the inner ring of the test bearing via the rolling element.

前記回転駆動手段を、回転軸と平行にモータで回転駆動される駆動軸を設け、回転軸に試験軸受の取り付け部から延長された延長部を設けて、この回転軸の延長部と駆動軸とにプーリを取り付け、これらのプーリ間に無端ベルトを張り渡して、回転軸をベルト駆動するものとし、荷重負荷手段を、無端ベルトの張力で回転軸の延長部に荷重を負荷するものとすることにより、別途の荷重負荷手段を不要とし、軸受試験装置をシンプルな構成とすることができる。 The rotation drive means is provided with a drive shaft that is rotated by a motor in parallel with the rotation shaft, and an extension portion that is extended from the mounting portion of the test bearing is provided on the rotation shaft. A pulley is attached to the belt, an endless belt is stretched between these pulleys, the rotating shaft is driven by the belt, and the load is applied to the extension of the rotating shaft by the tension of the endless belt. This eliminates the need for a separate load loading means, and allows the bearing test apparatus to have a simple configuration.

また、本発明の軸受試験方法は、試験軸受の外輪を剛性の低い外輪支持部材を介してハウジングに固定し、試験軸受の内輪と外輪との間に転動体を介して電流を流しながら、回転軸を回転駆動する方法を採用することにより、軸受に封入されるグリースから電気分解や、電食摩耗により生じた新生面の触媒作用によって強制的に水素を発生させるとともに、試験軸受内の振動やすべりを大きくして水素の発生を促進させるようにしたので、水素脆化に起因する脆性剥離を短時間で的確に再現でき、このような脆性剥離の発生する恐れがある用途に使用される転がり軸受の設計、開発、品質保証等に有効に活用することができる。 In the bearing test method of the present invention, the outer ring of the test bearing is fixed to the housing via the outer ring support member having low rigidity, and the current is passed through the rolling element between the inner ring and the outer ring of the test bearing. By adopting a method of rotating the shaft, hydrogen is forcibly generated from the grease enclosed in the bearing by electrolysis or catalysis of the new surface caused by electrolytic corrosion, and vibration and slip in the test bearing are also generated. Rolling bearings used for applications where brittle delamination due to hydrogen embrittlement can be accurately reproduced in a short time and there is a risk of such brittle delamination. Can be effectively used for design, development, quality assurance, etc.

以下、図面に基づき、本発明の実施形態を説明する。図１は、第１の実施形態を示す。この軸受試験装置は、回転軸１が試験軸受２とダミー軸受３とで互いに絶縁された別々のハウジング４ａ、４ｂに支持され、試験軸受２の取り付け部から延長された回転軸１の延長部１ａと、回転軸１と平行に配設されたモータ５の出力軸５ａとに、それぞれプーリ６ａ、６ｂが取り付けられて、これらのプーリ６ａ、６ｂ間に無端ベルト７が張り渡されており、回転軸１がベルト駆動されるとともに、回転軸１の延長部１ａを介して、無端ベルト７の張力で試験軸受２にラジアル荷重が負荷されるようになっている。なお、回転軸１と出力軸５ａとの間にプーリを取り付けた中間軸を設け、この中間軸を介して回転軸１をベルト駆動するようにしてもよい。この場合は、中間軸の位置を調節することにより、中間軸と回転軸１の延長部１ａに張り渡される無端ベルト７の張力を変化させることができる。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment. In this bearing test apparatus, the rotating shaft 1 is supported by separate housings 4 a and 4 b that are insulated from each other by the test bearing 2 and the dummy bearing 3, and the extending portion 1 a of the rotating shaft 1 extended from the mounting portion of the test bearing 2. Pulleys 6a and 6b are respectively attached to an output shaft 5a of a motor 5 arranged in parallel with the rotary shaft 1, and an endless belt 7 is stretched between the pulleys 6a and 6b, The shaft 1 is driven by a belt, and a radial load is applied to the test bearing 2 by the tension of the endless belt 7 via the extension 1 a of the rotating shaft 1. An intermediate shaft with a pulley attached may be provided between the rotary shaft 1 and the output shaft 5a, and the rotary shaft 1 may be belt-driven via this intermediate shaft. In this case, by adjusting the position of the intermediate shaft, the tension of the endless belt 7 stretched between the intermediate shaft and the extended portion 1a of the rotary shaft 1 can be changed.

前記試験軸受２とダミー軸受３の各内輪２ａ、３ａ、外輪２ｂ、３ｂおよび転動体としてのボール２ｃ、３ｃは、いずれも導電体である鋼で形成され、各内輪２ａ、３ａが互いに間隔を開けて回転軸１に取り付けられており、試験軸受２の外輪２ｂは、縦弾性係数が１０×１０^４ＭＰａ以下の材料で形成された剛性の低い環状の外輪支持部材８を介してハウジング４ａに固定され、ダミー軸受３の外輪３ｂは直接ハウジング４ｂに固定されている。図示は省略するが、試験軸受２とダミー軸受３にはグリースが封入されている。 The inner rings 2a and 3a, the outer rings 2b and 3b of the test bearing 2 and the dummy bearing 3 and the balls 2c and 3c as rolling elements are all formed of steel as a conductor, and the inner rings 2a and 3a are spaced from each other. The outer ring 2b of the test bearing 2 is opened and attached to the rotary shaft 1, and the outer ring 2b of the test bearing 2 is attached to the housing 4a via a low-rigidity annular outer ring support member 8 formed of a material having a longitudinal elastic modulus of 10 × 10 ⁴ MPa or less. The outer ring 3b of the dummy bearing 3 is fixed directly to the housing 4b. Although illustration is omitted, grease is sealed in the test bearing 2 and the dummy bearing 3.

前記回転軸１と各ハウジング４ａ、４ｂも導電体である鋼で形成され、各ハウジング４ａ、４ｂには、それぞれ電源（図示省略）のプラスとマイナスに接続される接点端子９ａ、９ｂが取り付けられており、これらの接点端子９ａ、９ｂを電源に接続することにより、ハウジング４ａから試験軸受２の外輪２ｂ、ボール２ｃ、内輪２ａ、回転軸１、ダミー軸受３の内輪３ａ、ボール３ｃ、外輪３ｂを順に介してハウジング４ｂへ電流が流れるようになっている。なお、試験軸受２の外輪２ｂとハウジング４ａ間は、外輪２ｂの内側端面がハウジング４ａの段差面と接触することにより導通されており、外輪支持部材８をアルミニウム等の導電体で形成した場合は、外輪支持部材８を介して外輪２ｂとハウジング４ａ間を導通することもできる。したがって、試験軸受２に封入されたグリースから電気分解によって強制的に水素を発生させるとともに、剛性の低い外輪支持部材を介してハウジングに固定した試験軸受内の振動やすべりを大きくして水素の発生を促進させ、水素脆化に起因する脆性剥離を短時間で的確に再現することができる。 The rotating shaft 1 and the housings 4a and 4b are also formed of steel as a conductor, and contact terminals 9a and 9b are attached to the housings 4a and 4b. By connecting these contact terminals 9a, 9b to a power source, the outer ring 2b, the ball 2c, the inner ring 2a, the rotating shaft 1, the inner ring 3a, the ball 3c, and the outer ring 3b of the dummy bearing 3 are connected to the test bearing 2 from the housing 4a. The current flows to the housing 4b through the steps. The outer ring 2b of the test bearing 2 and the housing 4a are electrically connected by the inner end surface of the outer ring 2b coming into contact with the stepped surface of the housing 4a, and the outer ring support member 8 is made of a conductor such as aluminum. The outer ring 2b and the housing 4a can be electrically connected via the outer ring support member 8. Therefore, hydrogen is forcibly generated by electrolysis from the grease sealed in the test bearing 2, and hydrogen is generated by increasing vibration and slip in the test bearing fixed to the housing via the outer ring support member having low rigidity. And brittle peeling due to hydrogen embrittlement can be accurately reproduced in a short time.

上述した軸受試験装置を用いて、接点端子９ａ、９ｂ間に通電し、回転軸１を図２に示すような、加減速を繰り返す回転サイクルで駆動する軸受寿命試験を行った。実施例としては、外輪支持部材８をアルミニウムで形成した場合（実施例１）と、外輪支持部材８をフェノール樹脂で形成した場合（実施例２）とについて試験を行い、比較例として、試験軸受２の外輪２ｂを直接ハウジング４ａに固定した場合の試験を行った。また、参考例として、比較例と同じ条件で、接点端子９ａ、９ｂ間に通電しない場合の試験も行った。試験軸受のサンプル数は、実施例、比較例および参考例とも２個ずつとし、軸受寿命は回転軸１の駆動トルクの変化で判定した２個の試験軸受２の平均寿命で評価した。試験条件は以下の通りである。
・試験軸受：呼び番号６２０３の深溝玉軸受（外径４０ｍｍ、内径１７ｍｍ、幅１２ｍｍ）
・グリース：ウレア系グリース（基油：合成炭化水素油）
・負荷荷重：２４０ｋｇｆ（Ｐ／Ｃ＝０．２４）
・通電条件：端子間電圧２Ｖ、電流０．５Ａ（参考例は除く）
・試験時間：３００時間で打ち切り Using the bearing test apparatus described above, a bearing life test was conducted in which a current was applied between the contact terminals 9a and 9b and the rotating shaft 1 was driven in a rotational cycle in which acceleration and deceleration were repeated as shown in FIG. As an example, a test was performed when the outer ring support member 8 was formed of aluminum (Example 1) and when the outer ring support member 8 was formed of a phenol resin (Example 2). The test was conducted when the outer ring 2b of 2 was fixed directly to the housing 4a. Further, as a reference example, a test was conducted in the case where no current was supplied between the contact terminals 9a and 9b under the same conditions as in the comparative example. The number of samples of the test bearing was two for each of the example, the comparative example, and the reference example, and the bearing life was evaluated based on the average life of the two test bearings 2 determined by the change in the driving torque of the rotating shaft 1. The test conditions are as follows.
Test bearing: Nominal deep groove ball bearing 6203 (outer diameter 40 mm, inner diameter 17 mm, width 12 mm)
・ Grease: Urea grease (Base oil: Synthetic hydrocarbon oil)
・ Load: 240kgf (P / C = 0.24)
・ Energizing conditions: Voltage between terminals 2V, current 0.5A (excluding reference examples)
・ Test time: Censored in 300 hours

上記軸受寿命試験の結果を表１に示す。比較例では軸受寿命が３７時間であったのに対して、試験軸受を剛性の低い外輪支持部材を介してハウジングに固定した実施例１および実施例２では、いずれも軸受寿命が比較例のものの半分以下となった。なお、試験軸受に電流を流さない参考例では軸受寿命が試験時間の３００時間を超えた。また、各実施例と比較例の試験軸受を試験後に分解して目視観察した結果、いずれも固定輪である外輪の軌道面に脆性剥離が発生していることが確認された。以上の試験結果より、本発明に係る軸受試験装置および軸受試験方法は、水素脆化に起因する脆性剥離を短時間で的確に再現できることを確認できた。 The results of the bearing life test are shown in Table 1. In the comparative example, the bearing life was 37 hours, whereas in Examples 1 and 2 in which the test bearing was fixed to the housing via the outer ring support member having low rigidity, the bearing life was that of the comparative example. Less than half. In the reference example in which no current was supplied to the test bearing, the bearing life exceeded the test time of 300 hours. Moreover, as a result of disassembling and visually observing the test bearings of the examples and comparative examples after the test, it was confirmed that brittle delamination occurred on the raceway surface of the outer ring which is a fixed ring. From the above test results, it was confirmed that the bearing test apparatus and the bearing test method according to the present invention can accurately reproduce the brittle peeling due to hydrogen embrittlement in a short time.

図３は、第２の実施形態を示す。この軸受試験装置は、前記環状の外輪支持部材８が鋼で形成され、中空とされて剛性の低いものとなっている点が異なる。その他の部分は、第１の実施形態のものと同じである。 FIG. 3 shows a second embodiment. This bearing test apparatus is different in that the annular outer ring support member 8 is made of steel and is hollow and has low rigidity. Other parts are the same as those of the first embodiment.

上述した実施形態では、試験軸受を深溝玉軸受とし、試験軸受にラジアル荷重を負荷したが、本発明に係る軸受試験装置および軸受試験方法は、ころ軸受等の他の転がり軸受を試験軸受とすることもでき、これらの試験軸受にはスラスト荷重も負荷することができる。 In the embodiment described above, the test bearing is a deep groove ball bearing and a radial load is applied to the test bearing. However, the bearing test apparatus and the bearing test method according to the present invention use other rolling bearings such as roller bearings as test bearings. These test bearings can also be loaded with thrust loads.

第１の実施形態の軸受試験装置を示す縦断面図1 is a longitudinal sectional view showing a bearing test apparatus according to a first embodiment. 図１の軸受試験装置を用いた軸受寿命試験における回転軸の回転サイクルを示すグラフA graph showing a rotation cycle of a rotating shaft in a bearing life test using the bearing test apparatus of FIG. 第２の実施形態の軸受試験装置を示す縦断面図A longitudinal sectional view showing a bearing test apparatus according to a second embodiment

符号の説明Explanation of symbols

１回転軸
１ａ延長部
２試験軸受
３ダミー軸受
２ａ、３ａ内輪
２ｂ、３ｂ外輪
２ｃ、３ｃボール
４ａ、４ｂハウジング
５モータ
５ａ出力軸
６ａ、６ｂプーリ
７無端ベルト
８外輪支持部材
９ａ、９ｂ接点端子 DESCRIPTION OF SYMBOLS 1 Rotating shaft 1a Extension part 2 Test bearing 3 Dummy bearing 2a, 3a Inner ring 2b, 3b Outer ring 2c, 3c Ball 4a, 4b Housing 5 Motor 5a Output shaft 6a, 6b Pulley 7 Endless belt 8 Outer ring support member 9a, 9b Contact terminal

Claims

内外輪および転動体が導電体で形成された試験軸受の内輪を取り付ける回転軸と、前記試験軸受の外輪を固定するハウジングとを有し、前記回転軸を回転駆動する回転駆動手段と、前記試験軸受に荷重を負荷する荷重負荷手段とを設けた軸受試験装置において、前記試験軸受の内輪と外輪との間に前記転動体を介して電流を流す通電手段を設け、前記試験軸受の外輪を剛性の低い外輪支持部材を介して前記ハウジングに固定したことを特徴とする軸受試験装置。 A rotating shaft for mounting an inner ring of a test bearing in which inner and outer rings and rolling elements are made of a conductor; a housing for fixing the outer ring of the test bearing; and a rotation driving means for rotating the rotating shaft, and the test In a bearing test apparatus provided with a load loading means for applying a load to the bearing, an energization means for passing a current through the rolling elements is provided between the inner ring and the outer ring of the test bearing, and the outer ring of the test bearing is rigid. A bearing test apparatus, wherein the bearing test apparatus is fixed to the housing via a low outer ring support member.

前記通電手段が、前記回転軸を前記試験軸受と離れた位置で支持し、内外輪および転動体が導電体で形成されたダミー軸受を設け、このダミー軸受の外輪を、前記試験軸受の外輪を固定したハウジングと絶縁した別のハウジングに固定して、これらの試験軸受とダミー軸受の各ハウジングおよび前記回転軸を導電体で形成し、前記外輪支持部材を介在させた前記試験軸受の外輪とハウジング間を、外輪支持部材を導電体で形成するか、または外輪とハウジング間に接触部位を設けて導通させ、前記試験軸受とダミー軸受のハウジング間に通電するものである請求項１に記載の軸受試験装置。 The energizing means supports the rotating shaft at a position away from the test bearing, and provides a dummy bearing in which inner and outer rings and rolling elements are formed of a conductor. The outer ring of the dummy bearing is used as the outer ring of the test bearing. An outer ring and a housing of the test bearing in which the housing of the test bearing and the dummy bearing and the rotating shaft are formed of a conductor and the outer ring support member is interposed. The bearing according to claim 1, wherein the outer ring support member is formed of a conductor, or a contact portion is provided between the outer ring and the housing so as to conduct electricity and the test bearing and the dummy bearing housing are energized. Test equipment.

前記回転駆動手段が、前記回転軸と平行にモータの出力軸を配設し、前記回転軸に試験軸受の取り付け部から延長された延長部を設けて、この回転軸の延長部と前記モータの出力軸とにプーリを取り付け、これらのプーリ間に無端ベルトを張り渡して、前記回転軸をベルト駆動するものであり、前記荷重負荷手段が、前記無端ベルトの張力で前記回転軸の延長部に荷重を負荷するものである請求項１または２に記載の軸受試験装置。 The rotation drive means arranges an output shaft of the motor in parallel with the rotation shaft, and provides an extension portion extended from the mounting portion of the test bearing on the rotation shaft, and the extension portion of the rotation shaft and the motor A pulley is attached to the output shaft, an endless belt is stretched between these pulleys, and the rotary shaft is driven by the belt, and the load-loading means is attached to the extension portion of the rotary shaft by the tension of the endless belt. The bearing test apparatus according to claim 1, wherein a load is applied.

前記回転駆動手段が、加減速を繰り返す回転サイクルを付与できるものである請求項１乃至３のいずれかに記載の軸受試験装置。 The bearing test apparatus according to any one of claims 1 to 3, wherein the rotation driving means can apply a rotation cycle that repeats acceleration and deceleration.

前記荷重負荷手段によって前記試験軸受に負荷される動等価荷重Ｐと、試験軸受の基本動定格荷重Ｃとの比Ｐ／Ｃを０．０５以上とした請求項１乃至４のいずれかに記載の軸受試験装置。 The ratio P / C between the dynamic equivalent load P loaded on the test bearing by the load loading means and the basic dynamic load rating C of the test bearing is set to 0.05 or more. Bearing test equipment.

前記剛性の低い外輪支持部材を、縦弾性係数が１０×１０^４ＭＰａ以下の材料で形成した請求項１乃至５のいずれかに記載の軸受試験装置。 The bearing test apparatus according to claim 1, wherein the outer ring supporting member having low rigidity is formed of a material having a longitudinal elastic modulus of 10 × 10 ⁴ MPa or less.

前記剛性の低い外輪支持部材を、中空の材料で形成した請求項１乃至６のいずれかに記載の軸受試験装置。 The bearing test apparatus according to claim 1, wherein the outer ring supporting member having low rigidity is formed of a hollow material.

内外輪および転動体が導電体で形成された試験軸受の内輪を回転軸に取り付け、前記試験軸受の外輪をハウジングに固定して、前記試験軸受に荷重を負荷しながら、前記回転軸を回転駆動する軸受試験方法において、前記試験軸受の外輪を剛性の低い外輪支持部材を介して前記ハウジングに固定し、前記試験軸受の内輪と外輪との間に前記転動体を介して電流を流しながら、前記回転軸を回転駆動するようにしたことを特徴とする軸受試験方法。 An inner ring of a test bearing in which inner and outer rings and rolling elements are formed of a conductor are attached to a rotating shaft, the outer ring of the test bearing is fixed to a housing, and the rotating shaft is driven to rotate while applying a load to the test bearing. In the bearing test method, the outer ring of the test bearing is fixed to the housing via an outer ring support member having low rigidity, and an electric current is passed between the inner ring and the outer ring of the test bearing via the rolling element, A bearing test method characterized in that a rotary shaft is driven to rotate.