JP2009270173A - Heat treatment method for bearing ring for radial bearing - Google Patents

Heat treatment method for bearing ring for radial bearing Download PDF

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JP2009270173A
JP2009270173A JP2008123370A JP2008123370A JP2009270173A JP 2009270173 A JP2009270173 A JP 2009270173A JP 2008123370 A JP2008123370 A JP 2008123370A JP 2008123370 A JP2008123370 A JP 2008123370A JP 2009270173 A JP2009270173 A JP 2009270173A
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raceway
heating
radial bearing
inner ring
bearing
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Yuji Miyamoto
祐司 宮本
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NSK Ltd
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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
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/58—Raceways; Race rings
    • F16C33/64—Special methods of manufacture
    • 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

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)
  • General Induction Heating (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment method which can not only increase an amount of retained austenite on a surface layer part of a raceway surface, but also can inhibit the increase of an amount of retained austenite on a part except the surface layer part. <P>SOLUTION: This heat treatment method includes sequentially induction-heating an inner ring 5 by supplying a high-frequency power having a frequency with a fixed cycle to a high-frequency heating coil 9 having a first heating part 12 and a second heating part 13 which have different diameters from each other. The heat treatment method also includes: a first step of firstly, uniformly heating the whole inner ring 5 to the transformation point A1 or higher with the first heating part 12 which has a larger clearance C1 between the inner ring 5 and the first heating part; and a second step of subsequently heating only the surface layer part of a raceway 4 of the inner ring to a higher temperature with the second heating part 13 which has a smaller clearance C2 between the raceway 4 of the inner ring and the second heating part. The above problem can be solved by the above heat treatment method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

この発明は、自動車、工作機械、産業機械、その他各種一般機械の回転支持部に組み込んだ状態で使用するラジアル軸受を構成する軌道輪の熱処理方法の改良に関する。具体的には、異物混入潤滑環境下での転がり疲れ寿命の向上を図れると共に、寸法安定性に優れた軌道輪を得る為の熱処理方法（特に焼入れ処理時の加熱方法）を実現するものである。尚、本発明の熱処理方法の対象となるラジアル軸受用軌道輪は、ラジアル玉軸受を構成する軌道輪に限らず、ラジアル円筒ころ軸受、ラジアル円すいころ軸受、自動調心ころ軸受を構成する軌道輪も含む。但し、以下の説明は、最も一般的なラジアル軸受であるラジアル玉軸受を構成する軌道輪を中心に行う。   The present invention relates to an improvement in a heat treatment method for a bearing ring constituting a radial bearing used in a state of being incorporated in a rotation support portion of an automobile, a machine tool, an industrial machine, and various other general machines. Specifically, it is possible to improve the rolling fatigue life in a foreign matter-contaminated lubrication environment, and to realize a heat treatment method (particularly a heating method during quenching) for obtaining a bearing ring with excellent dimensional stability. . The bearing ring for the radial bearing to be subjected to the heat treatment method of the present invention is not limited to the bearing ring constituting the radial ball bearing, but the bearing ring constituting the radial cylindrical roller bearing, the radial tapered roller bearing, and the self-aligning roller bearing. Including. However, the following description will be focused on the bearing ring constituting the radial ball bearing which is the most general radial bearing.

自動車用の変速機等、各種回転機械装置の回転支持部に、例えば図２に示す様なラジアル玉軸受１が組み込まれている。このラジアル玉軸受１は、内周面に外輪軌道２を有する外輪３と、外周面に内輪軌道４を有する内輪５と、これら外輪軌道２と内輪軌道４との間に設けた、それぞれが転動体である玉６、６とを備える。これら各玉６、６は、円周方向等間隔に配置された状態で、保持器７により、転動自在に保持されている。この様なラジアル玉軸受１は、例えば上記外輪３をハウジングに内嵌固定すると共に、上記内輪５を回転軸に外嵌固定する事により、この回転軸を上記ハウジングに対し、回転自在に支持する。   For example, a radial ball bearing 1 as shown in FIG. 2 is incorporated in a rotation support portion of various rotary machine devices such as a transmission for an automobile. The radial ball bearing 1 includes an outer ring 3 having an outer ring raceway 2 on an inner peripheral surface, an inner ring 5 having an inner ring raceway 4 on an outer peripheral surface, and an outer ring raceway 2 and an inner ring raceway 4 provided between the outer ring raceway 2 and the inner ring raceway 4. Balls 6 and 6 which are moving objects are provided. These balls 6, 6 are held by a cage 7 so as to be able to roll while being arranged at equal intervals in the circumferential direction. Such a radial ball bearing 1 is configured such that, for example, the outer ring 3 is fitted and fixed to the housing, and the inner ring 5 is fitted and fixed to the rotating shaft, thereby rotatably supporting the rotating shaft with respect to the housing. .

この様なラジアル玉軸受１を含め、何れかの周面に軌道面を有する１対の軌道輪と複数個の転動体とを組み合わせて成るラジアル軸受の場合、長期間に亙る使用に伴って軌道面に剥離が発生し、寿命に達する事が広く知られている。特に、上記ラジアル玉軸受１を潤滑する為の潤滑油やグリース中に混入した、金属粉等の硬い異物が、転がり接触部に噛み込まれると、上記外輪軌道２又は上記内輪軌道４に早期に剥離が発生して、上記ラジアル玉軸受１の耐久性が著しく損なわれる事が知られている。   In the case of a radial bearing comprising a combination of a pair of bearing rings each having a raceway surface and a plurality of rolling elements, including such a radial ball bearing 1, the raceway will be used with long-term use. It is widely known that peeling occurs on the surface and the lifetime is reached. In particular, when hard foreign matter such as metal powder mixed in the lubricating oil or grease for lubricating the radial ball bearing 1 is caught in the rolling contact portion, the outer ring raceway 2 or the inner ring raceway 4 is quickly brought into contact. It is known that peeling occurs and the durability of the radial ball bearing 1 is significantly impaired.

この様な異物混入潤滑環境下での早期剥離を抑えて、転がり疲れ寿命を向上させる手段として、例えば特許文献１に記載される等により従来から知られている様な、軌道面の表層部に存在する残留オーステナイト量を増加させる方法がある。又、上記特許文献１には、転がり疲れ寿命を向上させる面から、軌道面の表層部の残留オーステナイト量を２０容量％以上確保する事が有効である旨が記載されている。尚、残留オーステナイトの存在により、剥離の発生を抑えて、転がり疲れ寿命の延長を図れる理由は、この残留オーステナイトが柔らかく粘りのある組織であり、上記表層部に加わる応力を緩和できる為である。   As a means for suppressing the early peeling under such a foreign matter-contaminated lubrication environment and improving the rolling fatigue life, for example, as described in Patent Document 1, the surface layer portion of the raceway surface has been conventionally known. There are ways to increase the amount of residual austenite present. Further, Patent Document 1 describes that it is effective to secure a residual austenite amount of 20 volume% or more in the surface layer portion of the raceway surface from the viewpoint of improving the rolling fatigue life. The reason why the presence of retained austenite suppresses the occurrence of peeling and extends the rolling fatigue life is that this retained austenite is a soft and sticky structure and can relieve the stress applied to the surface layer portion.

ところで、上述の様に、軌道面の表層部に存在する残留オーステナイト量を増加させる為には、例えば、浸炭処理或は浸炭窒化処理によって、表層部の炭素量或は窒素量を高めた後、焼入れ・焼戻し処理を施す方法がある。又、上記軌道輪を、ラジアル軸受の構成各部材を構成する材料として一般的な、高炭素クロム軸受鋼から造る場合には、上述の様な浸炭処理や浸炭窒化処理によらずに、焼入れ温度を高温にする事によって、表層部の残留オーステナイト量を増加させる事もできる。   By the way, as described above, in order to increase the amount of retained austenite existing in the surface layer portion of the raceway surface, for example, after increasing the carbon amount or nitrogen amount of the surface layer portion by carburizing treatment or carbonitriding treatment, There are methods of quenching and tempering. In addition, when the bearing ring is made of high carbon chrome bearing steel, which is a general material constituting each component of the radial bearing, the quenching temperature is not used regardless of the carburizing treatment or carbonitriding treatment as described above. It is possible to increase the amount of retained austenite in the surface layer portion by increasing the temperature.

ところが、従来から知られている、上述した何れの方法を採用した場合にも、残留オーステナイト量を増やす必要のある、上記軌道面の表層部以外の部分に、多くの残留オーステナイトが生成されていた。この理由は、上記何れの方法を採用した場合にも、焼入れ処理として、炉内雰囲気中での焼入れ処理が採用されており、軌道面の表層部と、それ以外の部分とで焼入れ温度に差を持たせていなかった為である。この様な理由により、軌道面の表層部以外の部分の残留オーステナイト量が増加し、軌道輪の寸法安定性を害すると言った問題を生じていた。   However, in the case where any of the above-described methods is used, a large amount of retained austenite is generated in a portion other than the surface layer portion of the raceway surface, in which the amount of retained austenite needs to be increased. . The reason for this is that any of the above methods employs a quenching treatment in the furnace atmosphere as the quenching treatment, and the difference in quenching temperature between the surface layer portion of the raceway surface and the other portions. This is because I did not have. For these reasons, the amount of retained austenite in the portion other than the surface layer portion of the raceway surface is increased, causing a problem that the dimensional stability of the raceway is impaired.

上述の様な問題を解決する為には、残留オーステナイト量を多く確保する必要のある、軌道面の表層部の焼入れ温度を、他の部分に比べて高くする事が考えられる。そして、この様に、表層部のみ高温で焼入れする方法としては、従来から高周波加熱コイルを利用した焼入れ方法が知られている。例えば特許文献２〜５には、高周波加熱コイルを利用した焼入れ方法に関して、歯車を構成する各歯の表層部（極表面）のみをオーステナイト化し、歯形に沿った焼入れパターンを得る方法が記載されている。具体的には、上記特許文献２〜５に記載された各発明の場合には、予加熱と本加熱との２ステップの加熱を行う事により、上記各歯の表層部のみをＡ１（或はＡ３）変態点以上に加熱し、それ以外の部分にはＡ１変態点以下の温度勾配を得る様にしている。   In order to solve the above-described problems, it is conceivable to increase the quenching temperature of the surface layer portion of the raceway surface, which requires a large amount of retained austenite, as compared with other portions. In this way, as a method of quenching only the surface layer portion at a high temperature, a quenching method using a high-frequency heating coil has been conventionally known. For example, Patent Documents 2 to 5 describe a method for obtaining a quenching pattern along the tooth profile by austenizing only the surface layer portion (pole surface) of each tooth constituting the gear with respect to a quenching method using a high-frequency heating coil. Yes. Specifically, in the case of each invention described in Patent Documents 2 to 5, only the surface layer portion of each tooth is made A1 (or by performing two-step heating including preheating and main heating. A3) Heating is performed above the transformation point, and a temperature gradient below the A1 transformation point is obtained in the other portions.

この様に、歯車を対象として焼入れ処理を施す場合には、各歯の表層部以外の部分を、Ａ１変態点以下にする事ができる。これに対し、ラジアル軸受を構成する軌道輪を対象として焼入れ処理を施す場合には、芯部の靱性を確保する事で、この芯部の強度を十分に確保する必要がある為、軌道輪全体を、Ａ１変態点以上に、且つ、均一に加熱し、オーステナイト化する必要がある。この様な相違に基づき、上記特許文献２〜５に記載された各発明を、単に、軌道輪の焼入れ処理に適用した場合には、次の様な不都合を生じる。   In this way, when the quenching process is performed on the gear, the portion other than the surface layer portion of each tooth can be set to the A1 transformation point or less. On the other hand, when quenching treatment is performed on the bearing ring constituting the radial bearing, it is necessary to ensure the strength of the core part by ensuring the toughness of the core part. Must be heated to the A1 transformation point or more and uniformly to austenite. Based on such a difference, when the inventions described in Patent Documents 2 to 5 are simply applied to the quenching process of the race, the following inconvenience occurs.

即ち、上記特許文献２〜５に記載された各発明の方法により、軌道輪を誘導加熱する場合、この軌道輪に、高周波加熱コイル側から径方向反対側にかけて、大きな温度勾配を生じる。この様な温度勾配は、Ａ１変態点以下の温度では、軌道輪の品質に何ら影響を与える事はないが、軌道輪全体をＡ１変態点以上にまで加熱する場合には、芯部の温度がＡ１変態点を大きく超えて、この芯部の残留オーステナイト量を必要以上に増加させる原因となる。この為、やはり軌道輪の寸法安定性を害してしまう。   That is, when the raceway is induction-heated by the methods of the inventions described in Patent Documents 2 to 5, a large temperature gradient is generated in the raceway from the high-frequency heating coil side to the radially opposite side. Such a temperature gradient does not affect the quality of the raceway at temperatures below the A1 transformation point. However, when the entire raceway is heated to above the A1 transformation point, the core temperature is This greatly exceeds the A1 transformation point and causes the amount of retained austenite in the core to increase more than necessary. For this reason, the dimensional stability of the race is also impaired.

特に、浸炭処理や浸炭窒化処理によって軌道輪の表層部に形成された浸炭層や浸炭窒化層は、この軌道輪が高炭素鋼製或は中炭素鋼製であるかに拘わらず、焼入れ時の僅かな温度勾配によって、炭素の溶け込む量が変化する（残留オーステナイト量が変化する）。この為、上記特許文献２〜５に記載された各発明の方法を、軌道輪の焼入れ処理に適用した場合には、浸炭層或は浸炭窒化層のうちで軌道面の表層部以外の部分の残留オーステナイト量が、必要以上に増加する可能性がある。従って、この様な浸炭処理或は浸炭窒化処理後に行う焼入れ処理は、軌道面の表層部以外の部分に関しては、Ａ１変態点以上の温度でも、より低温で、且つ、均一に加熱し、軌道面の表層部に関しては、十分な量のオーステナイト量を確保する為に、他の部分に比べて高温で加熱する必要がある。但し、上記特許文献２〜５に記載された各発明の方法を含め、従来から知られた焼入れ方法では、この様な温度条件を満足する焼入れ処理を施す事はできない。   In particular, the carburized layer and the carbonitrided layer formed on the surface layer of the bearing ring by carburizing or carbonitriding treatment are not affected by whether the bearing ring is made of high carbon steel or medium carbon steel. A slight temperature gradient changes the amount of carbon dissolved (the amount of retained austenite changes). For this reason, when the method of each invention described in the above-mentioned patent documents 2 to 5 is applied to the quenching treatment of the raceway ring, the portion of the carburized layer or the carbonitrided layer other than the surface layer portion of the raceway surface. The amount of retained austenite may increase more than necessary. Therefore, the quenching process performed after such carburizing or carbonitriding is performed at a temperature lower than the A1 transformation point at a temperature other than the surface layer portion of the raceway surface at a lower temperature and uniformly. In order to ensure a sufficient amount of austenite, it is necessary to heat at a higher temperature than other portions. However, conventionally known quenching methods including the methods of the inventions described in Patent Documents 2 to 5 cannot perform quenching that satisfies such temperature conditions.

特開昭６４−５５４２３号公報Japanese Patent Laid-Open No. 64-55423 特開平９−２３５６２０号公報Japanese Patent Laid-Open No. 9-235620 特開平９−２４１７４９号公報JP-A-9-241749 特公平２−１４４０８号公報Japanese Patent Publication No. 2-14408 特開２００７−２７７７２８号公報JP 2007-277728 A

本発明は、上述の様な事情に鑑み、異物混入潤滑環境下での転がり疲れ寿命の向上を図れると共に、寸法安定性に優れたラジアル軸受用軌道輪を得られる熱処理方法を実現すべく発明したものである。具体的には、本発明は、軌道面の表層部の残留オーステナイト量を増加させるだけでなく、その他の部分の残留オーステナイト量の増加を抑制できる熱処理方法を実現すべく発明したものである。   In view of the circumstances as described above, the present invention has been invented to realize a heat treatment method capable of improving the rolling fatigue life in a foreign matter-mixed lubrication environment and obtaining a radial bearing race ring having excellent dimensional stability. Is. Specifically, the present invention was invented to realize a heat treatment method that can not only increase the amount of retained austenite in the surface layer portion of the raceway surface but also suppress the increase in the amount of retained austenite in other portions.

本発明のラジアル軸受用軌道輪の熱処理方法は、ラジアル軸受用軌道輪を、高周波加熱コイルにより加熱した後、冷却し、焼戻し処理を施す、熱処理方法に関する。
特に本発明のラジアル軸受用軌道輪の熱処理方法では、上記高周波加熱コイルとして、少なくとも互いに直径の異なる第一の加熱部と第二の加熱部とを有する、２ターン（巻き数）以上の高周波加熱コイルを使用する。
更に、この高周波加熱コイルは、上記ラジアル軸受用軌道輪を、上記第一の加熱部及び上記第二の加熱部の内径側或は外径側に、これら第一、第二の加熱部と同心にそれぞれ配置した状態で、このうちの第一の加熱部と上記ラジアル軸受用軌道輪とのクリアランスＣ１と、上記第二の加熱部とこのラジアル軸受用軌道輪のうちの軌道面とのクリアランスＣ２とが、Ｃ１＞Ｃ２の関係を満たすものである。 The radial bearing raceway heat treatment method of the present invention relates to a heat treatment method in which a radial bearing raceway is heated by a high-frequency heating coil and then cooled and tempered.
In particular, in the heat treatment method for radial bearing raceways of the present invention, high-frequency heating of two turns (number of turns) or more having at least a first heating section and a second heating section having different diameters as the high-frequency heating coil. Use a coil.
Further, the high-frequency heating coil is configured such that the radial bearing raceway is concentric with the first and second heating units on the inner diameter side or outer diameter side of the first heating unit and the second heating unit. The clearance C1 between the first heating portion and the radial bearing raceway, and the clearance C2 between the second heating portion and the raceway surface of the radial bearing raceway, respectively. Satisfies the relationship of C1> C2.

そして、本発明の熱処理方法では、この様な構成を有する高周波加熱コイルを用いて、次の第一工程と、第二工程との２ステップで加熱を施す。
先ず、第一工程として、上記ラジアル軸受用軌道輪を、上記第一の加熱部の内径側或は外径側に、この第一の加熱部と同心に配置する。そして、このラジアル軸受用軌道輪を、上記高周波加熱コイルに所定の周波数を有する高周波電力を供給して誘導加熱する。
次いで、第二工程として、上記ラジアル軸受用軌道輪を、上記第二の加熱部の内径側或は外径側に（ラジアル軸受用軌道輪が内輪である場合には内径側に、同じく外輪である場合には外径側に）、上記第二の加熱部と同心に配置する。そして、上記ラジル軸受用軌道輪を、上記第一工程で上記高周波加熱コイルに供給した高周波電力と同一周波数の高周波電力をこの高周波加熱コイルに供給して誘導加熱する。 And in the heat processing method of this invention, it heats in 2 steps, the following 1st process and 2nd process, using the high frequency heating coil which has such a structure.
First, as a first step, the radial bearing race is arranged concentrically with the first heating section on the inner diameter side or outer diameter side of the first heating section. The radial bearing race is induction-heated by supplying high-frequency power having a predetermined frequency to the high-frequency heating coil.
Next, as a second step, the radial bearing raceway is placed on the inner diameter side or the outer diameter side of the second heating section (if the radial bearing raceway is an inner ring, In some cases (on the outer diameter side), it is arranged concentrically with the second heating section. And the high frequency electric power of the same frequency as the high frequency electric power supplied to the said high frequency heating coil at the said 1st process is supplied to this high frequency heating coil, and the said lasil bearing race is induction-heated.

上述した請求項１に記載した発明を実施する場合に好ましくは、例えば請求項２に記載した発明の様に、上記第一の加熱部と上記ラジアル軸受用軌道輪との間に、非磁性材製の変形矯正型を配置し、このラジアル軸受用軌道輪の形状を矯正しながら、このラジアル軸受用軌道輪を加熱する。   When the invention described in claim 1 described above is carried out, preferably, as in the invention described in claim 2, for example, a nonmagnetic material is provided between the first heating portion and the radial bearing raceway. A radial deformation bearing ring is heated while correcting the shape of the radial bearing raceway.

更に本発明を実施する場合に好ましくは、例えば請求項３に記載した発明の様に、軌道面の表層部の残留オーステナイト量を２０〜５０容量％とし、軌道輪全体の平均残留オーステナイト量を１０容量％以下とする。   Further, when carrying out the present invention, preferably, for example, as in the invention described in claim 3, the amount of retained austenite in the surface layer portion of the raceway surface is set to 20 to 50% by volume, and the average amount of retained austenite of the entire raceway is set to 10%. Less than volume%.

尚、本発明を実施する場合に、第二工程後に行う冷却処理に関しては、その冷却方法は特に限定されないが、例えば液体又は高圧ガスを用いた噴射冷却による冷却方法が、好ましく採用できる。
又、本発明を実施する場合に、第一の加熱部によりラジアル軸受用軌道輪を均一に加熱し、第二の加熱部により軌道面の表層部のみを高温で加熱する面からは、クリアランスＣ１とクリアランスＣ２とを、Ｃ１＝（３〜５）×Ｃ２の関係を満たす様に規制する事が好ましい。 In carrying out the present invention, the cooling method performed after the second step is not particularly limited, but for example, a cooling method by jet cooling using liquid or high-pressure gas can be preferably employed.
Further, when the present invention is carried out, the clearance C1 from the surface where the radial ring is uniformly heated by the first heating unit and only the surface layer portion of the raceway surface is heated by the second heating unit. And the clearance C2 are preferably regulated so as to satisfy the relationship of C1 = (3-5) × C2.

尚、本発明の熱処理方法の対象となるラジアル軸受用軌道輪は、誘導加熱を行う為に、少なくとも磁性材製である必要がある。特に、本発明では、軌道面の表層部に十分な量の残留オーステナイト量を確保する面から、磁性材製の軌道輪のうちでも、浸炭処理或は浸炭窒化処理によって表層部に浸炭層或は浸炭窒化層が形成された軌道輪、或は、ＪＩＳ Ｇ ４８０５に規定される高炭素クロム軸受鋼（例えばＳＵＪ２、ＳＵＪ３）製の軌道輪等を対象とする。   In addition, the radial bearing ring used as the object of the heat treatment method of the present invention needs to be made of at least a magnetic material in order to perform induction heating. In particular, in the present invention, from the aspect of securing a sufficient amount of retained austenite in the surface layer portion of the raceway surface, even in the raceway ring made of magnetic material, the carburized layer or the surface layer portion by carburizing treatment or carbonitriding treatment. A bearing ring in which a carbonitriding layer is formed or a bearing ring made of a high carbon chromium bearing steel (for example, SUJ2, SUJ3) defined in JIS G 4805 is used.

上述した様な本発明のラジアル軸受用軌道輪の熱処理方法によれば、異物混入潤滑環境下での転がり疲れ寿命の延長を図れると共に、寸法安定性に優れたラジアル軸受用軌道輪を得られる。この理由は、次の通りである。
先ず、第一工程で、第一の加熱部とラジアル軸受用軌道輪との間のクリアランス（Ｃ１）を大きく設定した状態で誘導加熱する為、このラジアル軸受用軌道輪に温度勾配が生じにくい状態で、このラジアル軸受用軌道輪の温度を上昇させる事ができる。即ち、誘導加熱を行う際に、このラジアル軸受用軌道輪中に生じる渦電流の密度は、高周波加熱コイル（加熱部）からの距離が大きくなる程、指数関数的に低くなる。この為、上記クリアランスを大きく設定する事で、上記ラジアル軸受用軌道輪中の温度勾配を小さくできる。従って、本発明の場合には、ラジアル軸受用軌道輪を構成する鋼材の種類、軌道輪の肉厚等を考慮して、高周波電力の出力、周波数、加熱時間等を適宜設定する事で、上記ラジアル軸受用軌道輪全体を、Ａ１変態点以上に、且つ、均一に加熱する事ができる。 According to the above-described heat treatment method for a radial bearing raceway according to the present invention, it is possible to obtain a radial bearing raceway with excellent dimensional stability while extending the rolling fatigue life under a foreign matter-mixed lubrication environment. The reason for this is as follows.
First, in the first step, since the induction heating is performed with a large clearance (C1) between the first heating section and the radial bearing raceway, a temperature gradient is hardly generated in the radial bearing raceway. Thus, the temperature of the radial bearing race can be increased. That is, when performing induction heating, the density of eddy current generated in the radial bearing raceway decreases exponentially as the distance from the high-frequency heating coil (heating unit) increases. For this reason, the temperature gradient in the radial bearing race can be reduced by setting the clearance large. Therefore, in the case of the present invention, considering the type of steel material constituting the bearing ring for radial bearing, the thickness of the bearing ring, etc., by appropriately setting the output of the high frequency power, the frequency, the heating time, etc. The entire bearing ring for radial bearing can be heated uniformly above the A1 transformation point.

又、第二工程では、第二の加熱部と上記ラジアル軸受用軌道輪のうちの軌道面との間のクリアランス（Ｃ２）を小さく設定した状態で誘導加熱する為、上述した第一工程の場合とは反対に、上記ラジアル軸受用軌道輪中での温度勾配が大きくなる。この為、上記軌道面の表層部のみを高温で加熱する事ができる。従って、本発明の場合には、ラジアル軸受用軌道輪を構成する鋼材の種類、残留オーステナイト量を増加させようとする表層部の深さ等を考慮して、高周波電力の出力、周波数、加熱時間等を適宜設定する事で、上記軌道面の表層部以外の部分の温度がＡ１変態点を大幅に越えて上昇しない様に、この表層部以外の部分の温度上昇を抑えた状態で、この軌道面の表層部の温度のみを、十分な量の残留オーステナイトを確保する為に必要な温度にまで上昇させる事ができる。   In the second step, the induction heating is performed in a state where the clearance (C2) between the second heating portion and the raceway surface of the radial bearing raceway is set to be small. On the contrary, the temperature gradient in the radial bearing race is increased. For this reason, only the surface layer portion of the raceway surface can be heated at a high temperature. Accordingly, in the case of the present invention, the output of the high frequency power, the frequency, and the heating time are taken into consideration in consideration of the type of steel material constituting the bearing ring for the radial bearing, the depth of the surface layer portion to increase the retained austenite amount, etc. By appropriately setting, etc., the orbital surface of the orbital surface other than the surface layer does not rise significantly beyond the A1 transformation point. Only the surface temperature of the surface can be raised to the temperature required to ensure a sufficient amount of retained austenite.

この結果、本発明の場合には、軌道面の表層部の残留オーステナイト量を増加させる事ができるだけでなく、芯部を含む、軌道面の表層部以外の部分の残留オーステナイト量の増加を抑制する事ができる。更に、本発明の場合には、第一工程によって、軌道輪全体の組織をオーステナイト化する事ができる為、軌道輪の芯部の靱性を確保する事ができて、この芯部の強度を十分に確保できる。
この様な本発明の熱処理が施された軌道輪は、軌道面の表層部の残留オーステナイト量が十分に多くなる為、異物混入潤滑環境下に於いても、この軌道面に早期剥離が発生する事を防止できて、転がり疲れ寿命の延長を図れる。更に、芯部を含む、上記軌道面の表層部以外の部分の残留オーステナイト量が少ないままの状態になる為、寸法安定性に優れたものとなる。 As a result, in the case of the present invention, not only can the amount of retained austenite in the surface layer portion of the raceway surface be increased, but also the increase in the amount of retained austenite in portions other than the surface layer portion of the raceway surface including the core portion is suppressed. I can do things. Furthermore, in the case of the present invention, the structure of the entire race can be austenitized by the first step, so that the toughness of the core of the race can be ensured, and the strength of the core is sufficient. Can be secured.
In such a heat-treated race ring of the present invention, the amount of retained austenite on the surface portion of the raceway surface is sufficiently increased, so that even in a lubrication environment with foreign matter, early separation occurs on this raceway surface. You can prevent things and extend the rolling fatigue life. Furthermore, since the amount of retained austenite in the portion other than the surface layer portion of the raceway surface including the core portion remains small, the dimensional stability is excellent.

尚、本発明の場合には、上記第一、第二の加熱部と上記ラジアル軸受用軌道輪とのクリアランスＣ１、Ｃ２を、Ｃ１＞Ｃ２の関係に規制する事で、高周波加熱コイルに供給する高周波電力の周波数の大きさを、第一工程と第二工程との場合で同じにできる為、高周波加熱装置の構造及び制御を簡易にする事もできる。仮に、上記第一の加熱部と上記第二の加熱部との直径を同じとしたり、上記第一工程と上記第二工程とを単一の加熱部を用いて行う場合には、軌道輪全体を均一に加熱する為の周波数を数ｋＨｚ以下とし、軌道面の表層部のみを加熱する為の周波数を数百ｋＨｚとする必要があり、高周波加熱装置の構造及び制御が非常に煩雑になる。   In the case of the present invention, the clearances C1 and C2 between the first and second heating sections and the radial bearing raceway are restricted to a relationship of C1> C2 to be supplied to the high-frequency heating coil. Since the magnitude of the frequency of the high-frequency power can be made the same in the first step and the second step, the structure and control of the high-frequency heating device can be simplified. If the diameters of the first heating unit and the second heating unit are the same, or if the first step and the second step are performed using a single heating unit, the entire bearing ring It is necessary to set the frequency for heating the surface uniformly to several kHz or less and the frequency for heating only the surface layer portion of the raceway surface to several hundred kHz, which makes the structure and control of the high-frequency heating device very complicated.

又、前述した請求項２に記載した発明によれば、変形矯正型とラジアル軸受用軌道輪とを接触させる事で、このラジアル軸受用軌道輪の表面のうちで、他の部分に比べて温度上昇し易い、第一の加熱部側の周面の表面温度を、熱伝達により低下させる事ができる。この為、ラジアル軸受用軌道輪の温度勾配を十分に小さくする事ができて、このラジアル軸受用軌道輪の温度をより均一に上昇させる事ができる。更に、このラジアル軸受用軌道輪が熱処理変形する事を有効に防止する事もできる。   Further, according to the invention described in claim 2 described above, the deformation correction mold and the radial bearing raceway are brought into contact with each other, so that the temperature of the surface of the radial bearing raceway is higher than that of other portions. The surface temperature of the peripheral surface on the first heating unit side, which is likely to rise, can be reduced by heat transfer. For this reason, the temperature gradient of the bearing ring for radial bearing can be made sufficiently small, and the temperature of the bearing ring for radial bearing can be increased more uniformly. Furthermore, the radial bearing race can be effectively prevented from being deformed by heat treatment.

又、前述した請求項３に記載した発明の様に、軌道面の表層部の残留オーステナイト量を２０〜５０容量％確保すれば、異物混入潤滑環境下に於いても、早期剥離を防止できて、転がり疲れ寿命の延長を図れる。又、軌道輪全体の平均残留オーステナイト量を１０容量％以下と少なく抑えれば、軌道輪の寸法安定性を確保できる。これらの効果を得る為に、残留オーステナイト量を上記範囲に規制した理由は、次の通りである。
尚、残留オーステナイト量は、ラジアル軸受用軌道輪を構成する鋼材の種類、焼入れ温度（第一、第二の加熱部による加熱温度）、焼戻し温度、浸炭処理或は浸炭窒化処理の有無及びその処理条件等を変える事で、適宜設定する事ができる。 Further, as in the invention described in claim 3 described above, if the retained austenite amount of the surface layer portion of the raceway surface is secured in an amount of 20 to 50% by volume, early peeling can be prevented even in a foreign matter-mixed lubricating environment. Can extend the rolling fatigue life. Further, if the average retained austenite amount of the entire bearing ring is suppressed to 10% by volume or less, the dimensional stability of the bearing ring can be ensured. In order to obtain these effects, the reason why the amount of retained austenite is regulated within the above range is as follows.
The amount of retained austenite is the type of steel material constituting the bearing ring for the radial bearing, the quenching temperature (heating temperature by the first and second heating parts), the tempering temperature, the presence or absence of carburizing treatment or carbonitriding treatment, and its treatment. It can be set as appropriate by changing the conditions.

［軌道面の表層部の残留オーステナイト量を２０〜５０容量％］
前述した様に、残留オーステナイトは、柔らかく粘りのある組織である。そして、軌道輪を構成する鋼中で、軌道面の表層部に存在すると、繰り返し応力を受けた際のエネルギをマルテンサイト変態に利用する為、上記表層部に加わる応力を緩和できる。この為、早期剥離を防止して、転がり疲れ寿命の延長を図れる。但し、残留オーステナイトがマルテンサイトに変態（分解）する過程で、僅かとは言え体積が膨張するので、残留オーステナイト量が多過ぎると、寸法安定性が損なわれる。 [Residual austenite amount in the surface layer of the raceway surface is 20 to 50% by volume]
As described above, retained austenite is a soft and sticky structure. And if it exists in the surface layer part of a raceway surface in steel which comprises a bearing ring, since the energy at the time of receiving a repeated stress will be utilized for a martensitic transformation, the stress added to the said surface layer part can be relieved. For this reason, early peeling can be prevented and the rolling fatigue life can be extended. However, in the process of transformation (decomposition) of retained austenite to martensite, the volume expands although it is slight, and if the amount of retained austenite is too large, dimensional stability is impaired.

上記作用により、異物混入潤滑環境下で、転がり疲れ寿命の延長を十分に図る為には、軌道面の表層部の残留オーステナイト量を少なくとも２０容量％以上とする必要がある。更に、摩耗粉等の、厳しい異物混入が想定され、高い疲労強度が必要とされる場合に、好ましくは、上記軌道面の表層部の残留オーステナイト量を２５容量％以上確保する。但し、この表層部の残留オーステナイト量が５０容量％を超えると、上記軌道面の硬さが過度に低下して、材料強度が不足するだけでなく、表層部のみとは言え、残留オーステナイトの分解に伴う、寸法変化（膨張）が無視できなくなる。そこで、上記表層部の残留オーステナイト量の上限値を５０容量％とした。但し、後述する平均残留オーステナイト量を十分に低くできない場合には、寸法安定性を確保すべく、上記表層部の残留オーステナイト量の上限値は３５容量％とする。   Due to the above action, in order to sufficiently extend the rolling fatigue life under a foreign matter mixed lubrication environment, the amount of retained austenite in the surface layer portion of the raceway surface needs to be at least 20% by volume or more. Further, when severe foreign matter such as wear powder is expected to be mixed and high fatigue strength is required, the amount of retained austenite in the surface layer portion of the raceway surface is preferably secured by 25% by volume or more. However, if the amount of retained austenite in the surface layer exceeds 50% by volume, the hardness of the raceway surface is excessively lowered and the material strength is insufficient. The dimensional change (expansion) accompanying this cannot be ignored. Therefore, the upper limit of the amount of retained austenite in the surface layer portion was set to 50% by volume. However, when the average retained austenite amount described later cannot be sufficiently reduced, the upper limit value of the retained austenite amount in the surface layer portion is set to 35% by volume in order to ensure dimensional stability.

［軌道輪全体の平均残留オーステナイト量を１０容量％以下］
軌道輪全体としての残留オーステナイト量を少なく抑える程、この軌道輪全体としての寸法及び形状の変化を少なくできる。但し、上記表層部の残留オーステナイト量は、上述した様な理由により２０〜５０容量％確保する。この様に、表層部の残留オーステナイト量を或る程度確保する事を考えれば、寸法安定性を確保する為には、軌道輪全体の平均オーステナイト量は１０容量％以下とする必要がある。更に、寸法安定性を長期間に亙り確保する必要がある場合に、好ましくは、上記平均残留オーステナイト量は６容量％以下とする。 [The average retained austenite amount of the entire race is less than 10% by volume]
The smaller the amount of retained austenite for the entire bearing ring, the smaller the change in size and shape of the entire bearing ring. However, the amount of retained austenite in the surface layer portion is ensured by 20 to 50% by volume for the reason described above. In this way, in view of securing a certain amount of retained austenite in the surface layer portion, in order to ensure dimensional stability, the average austenite amount of the entire raceway needs to be 10% by volume or less. Furthermore, when it is necessary to ensure dimensional stability over a long period of time, the average retained austenite amount is preferably 6% by volume or less.

図１は、本発明の実施の形態の１例を示している。尚、本発明のラジアル軸受用軌道輪の熱処理方法の特徴は、軌道面の表層部の残留オーステナイト量を増加させるだけでなく、その他の部分の残留オーステナイト量の増加を抑える為の加熱方法にある。以下、ＪＩＳ Ｇ ４８０５に規定される高炭素クロム軸受鋼製の内輪５を対象に、本例の熱処理方法を施す場合に就いて説明する。   FIG. 1 shows an example of an embodiment of the present invention. The feature of the heat treatment method for the radial bearing raceway ring according to the present invention is not only to increase the amount of retained austenite in the surface layer portion of the raceway surface but also to a heating method for suppressing increase in the amount of retained austenite in other portions. . Hereinafter, the case where the heat treatment method of this example is applied to the inner ring 5 made of high carbon chromium bearing steel defined in JIS G 4805 will be described.

本例の熱処理方法には、図１に示す様な高周波加熱装置８を使用する。この高周波加熱装置８は、高周波加熱コイル９と、この高周波加熱コイル９に高周波電力を供給する為の高周波電源（高周波発振器）１０と、上記内輪５を所定位置に支持固定する為のワーク支持装置１１とから構成される。尚、このワーク支持装置１１は、セラミック等の非磁性材製で、昇降手段を備える。又、上記高周波加熱コイル９のインピーダンスが低い場合には、この高周波加熱コイル９と上記高周波電源１０との間に高周波変流器を介在させる事もできる。   In the heat treatment method of this example, a high-frequency heating device 8 as shown in FIG. 1 is used. The high-frequency heating device 8 includes a high-frequency heating coil 9, a high-frequency power source (high-frequency oscillator) 10 for supplying high-frequency power to the high-frequency heating coil 9, and a work support device for supporting and fixing the inner ring 5 at a predetermined position. 11. The work support device 11 is made of a non-magnetic material such as ceramic and includes lifting means. When the impedance of the high frequency heating coil 9 is low, a high frequency current transformer can be interposed between the high frequency heating coil 9 and the high frequency power source 10.

上記高周波加熱コイル９は、２ターン（巻き数）以上で、互いに直径の異なる第一の加熱部１２と第二の加熱部１３とを備える。又、これら第一、第二の加熱部１２、１３は、上記高周波加熱コイル９の軸方向（図１の上下方向）に、少なくとも上記内輪５の軸方向寸法L5 の１／２以上の大きさの隙間を設けて配置されている。 The high-frequency heating coil 9 includes a first heating unit 12 and a second heating unit 13 having two or more turns (number of turns) and different diameters. The first and second heating sections 12 and 13 are at least 1/2 or more of the axial dimension L 5 of the inner ring 5 in the axial direction of the high-frequency heating coil 9 (vertical direction in FIG. 1). It is arranged with a gap.

又、上記図１の（Ａ）及び（Ｂ）に示す様に、上記内輪５を、上記第一の加熱部１２及び上記第二の加熱部１３の内径側に、これら第一、第二の加熱部１２、１３と同心にそれぞれ配置した状態で、このうちの第一の加熱部１２と上記内輪５の外周面（最外周面）とのクリアランスＣ１と、上記第二の加熱部１３とこの内輪５の外周面に形成された内輪軌道４とのクリアランスＣ２とを、Ｃ１＞Ｃ２｛図示の例ではＣ１＝５×Ｃ２｝の関係を満たす様に規制している。尚、これらクリアランスＣ１、Ｃ２の具体的な大きさは、高周波加熱コイル９に供給する高周波電力の出力、周波数等に応じて決定するが、例えば外径が１２０mm、肉厚が４mm程度の軌道輪の場合で、Ｃ１を６〜１０mm程度、Ｃ２を２mm程度とする事ができる。又、本例の場合には、上記第一の加熱部１２の軸方向寸法Ｌ12を、上記内輪５の軸方向寸法L5 と同じとし（L12＝L5 ）、上記第二の加熱部１３の軸方向寸法L13を、上記内輪軌道４の幅寸法L4 と同じとしている（L13＝L4 ）。 Further, as shown in FIGS. 1A and 1B, the inner ring 5 is placed on the inner diameter side of the first heating unit 12 and the second heating unit 13 so that the first and second A clearance C1 between the first heating unit 12 and the outer circumferential surface (outermost circumferential surface) of the inner ring 5, the second heating unit 13 and the second heating unit 13 in a state of being arranged concentrically with the heating units 12 and 13, respectively. The clearance C2 with the inner ring raceway 4 formed on the outer peripheral surface of the inner ring 5 is regulated so as to satisfy the relationship C1> C2 {C1 = 5 × C2} in the illustrated example. The specific sizes of the clearances C1 and C2 are determined according to the output, frequency, etc. of the high frequency power supplied to the high frequency heating coil 9. For example, the races having an outer diameter of 120 mm and a wall thickness of about 4 mm. In this case, C1 can be about 6 to 10 mm, and C2 can be about 2 mm. In this example, the axial dimension L 12 of the first heating unit 12 is the same as the axial dimension L 5 of the inner ring 5 (L 12 = L 5 ), and the second heating unit 13 the axial dimension L 13 of, and equal to the width L 4 of the inner ring raceway 4 (L 13 = L 4) .

そして、本例の場合には、この様な構成を有する高周波加熱コイル９を用いて、上記内輪５に、次の第一工程と、第二工程との２ステップの加熱（焼入れ処理の加熱工程）を施す。
先ず、第一工程として、図１の（Ａ）に示す様に、上記内輪５を上記ワーク支持装置１１上に載置する事により、この内輪５を、上記第一の加熱部１２の内径側に、この第一の加熱部１２と同心に配置する。これにより、この内輪５の外周面を、全幅に亙り、この第一の加熱部１２に対向させる。尚、この状態で、これら第一の加熱部１２と内輪５の外周面との間には、全周に亙り、上記クリアランスＣ１が存在する。 In the case of this example, using the high-frequency heating coil 9 having such a configuration, the inner ring 5 is heated in two steps of the following first process and second process (heating process of quenching process). ).
First, as shown in FIG. 1A, as the first step, the inner ring 5 is placed on the work support device 11 so that the inner ring 5 is placed on the inner diameter side of the first heating unit 12. Furthermore, it arrange | positions concentrically with this 1st heating part 12. FIG. As a result, the outer peripheral surface of the inner ring 5 extends over the entire width and faces the first heating unit 12. In this state, the clearance C1 exists between the first heating unit 12 and the outer circumferential surface of the inner ring 5 over the entire circumference.

次いで、上記第一の加熱部１２の内周面と上記内輪５の外周面との間に、円筒状の変形矯正型１４を上方から挿入する。この変形矯正型１４は、窒化珪素セラミック等の非磁性、且つ、絶縁材製で、その外径寸法Ｄ14は上記第一の加熱部１２の内径寸法ｄ12よりも小さく（Ｄ14＜ｄ12）、その内径寸法ｄ14は上記内輪５の外径寸法Ｄ5 と同じかこれよりも僅かに大きい（ｄ14≧Ｄ5 ）。従って、上記変形矯正型１４を、上記第一の加熱部１２と上記内輪５との間に挿入した状態で、この変形矯正型１４の内周面は、この内輪５の外周面にほぼ全周に亙り接触する。尚、この内輪５を上記ワーク支持装置１１上に載置する以前に、上記変形矯正型１４をこの内輪５に外嵌しておく事もできる。 Next, a cylindrical deformation correction die 14 is inserted from above between the inner peripheral surface of the first heating unit 12 and the outer peripheral surface of the inner ring 5. The deformation correcting die 14 is made of a non-magnetic and insulating material such as silicon nitride ceramic, and its outer diameter D 14 is smaller than the inner diameter d 12 of the first heating unit 12 (D 14 <d 12 ), The inner diameter d 14 is equal to or slightly larger than the outer diameter D 5 of the inner ring 5 (d 14 ≧ D 5 ). Therefore, in a state where the deformation correction mold 14 is inserted between the first heating unit 12 and the inner ring 5, the inner peripheral surface of the deformation correction mold 14 is almost entirely around the outer peripheral surface of the inner ring 5. Touch to touch. Note that the deformation correction die 14 can be externally fitted to the inner ring 5 before the inner ring 5 is placed on the work support device 11.

この様な変形矯正型１４を、上記第一の加熱部１２と上記内輪５との間に挿入した後は、前記高周波加熱コイル９に、前記高周波電源１０から所定の周波数の高周波電力を供給する。これにより、上記第一の加熱部１２の周囲に交番電力を発生させて、上記内輪５を誘導加熱する。尚、高周波電力の周波数の大きさは、電流の浸透深さ（加熱範囲）に影響（反比例）する為、本例の場合には、この周波数の大きさを、後述する第二工程で、内輪軌道４の表層部のみを高温に加熱するのに必要な大きさ（数百ｋＨｚ）に設定している。   After such a deformation correction die 14 is inserted between the first heating unit 12 and the inner ring 5, high-frequency power of a predetermined frequency is supplied from the high-frequency power source 10 to the high-frequency heating coil 9. . Thereby, alternating power is generated around the first heating unit 12 to inductively heat the inner ring 5. In addition, since the magnitude of the frequency of the high frequency power affects (inversely proportional) the penetration depth (heating range) of the current, in the case of this example, the magnitude of this frequency is determined in the second step described later. The size (several hundred kHz) necessary for heating only the surface layer portion of the track 4 to a high temperature is set.

この様な第一工程では、上記第一の加熱部１２と上記内輪５との間のクリアランスＣ１（＝５×Ｃ２）が大きい為、この内輪５に温度勾配が生じにくい状態で、この内輪５の温度を上昇させる事ができる。即ち、誘導加熱を行う際に、この内輪５中に生じる渦電流の密度は、上記高周波加熱コイル９（第一の加熱部１２）からの距離が大きくなる程、指数関数的に低くなる。この為、上記クリアランスＣ１を大きく設定する事で、上記内輪５に生じる温度勾配は小さくなる。   In such a first process, since the clearance C1 (= 5 × C2) between the first heating unit 12 and the inner ring 5 is large, the inner ring 5 is in a state in which a temperature gradient hardly occurs in the inner ring 5. The temperature can be increased. That is, when performing induction heating, the density of eddy current generated in the inner ring 5 decreases exponentially as the distance from the high-frequency heating coil 9 (first heating unit 12) increases. For this reason, the temperature gradient generated in the inner ring 5 is reduced by setting the clearance C1 large.

加えて、本例の場合には、誘導加熱によっては温度上昇する事のない、非磁性、且つ、絶縁材製の変形矯正型１４の内周面を、上記内輪５の外周面にほぼ全周に亙り接触させている。この為、他の部分に比べて温度上昇し易い、上記内輪５の外周面の表面温度を、熱伝達により低下させる事ができる。この為、この内輪５の温度勾配を十分に小さくする事ができて、この内輪５の温度をより均一に上昇させる事ができる。   In addition, in the case of the present example, the inner peripheral surface of the non-magnetic and insulating deformation correcting die 14 that does not increase in temperature due to induction heating is almost entirely around the outer peripheral surface of the inner ring 5. In contact with For this reason, the surface temperature of the outer peripheral surface of the inner ring 5, which is likely to increase in temperature compared with other portions, can be reduced by heat transfer. For this reason, the temperature gradient of the inner ring 5 can be made sufficiently small, and the temperature of the inner ring 5 can be increased more uniformly.

従って、本例の場合には、上記内輪５の肉厚等を考慮して、上記高周波加熱コイル９（第一の加熱部１２）に供給する高周波電力の出力、加熱時間等を適宜設定する事で、上記内輪５全体を、Ａ１変態点以上に、且つ、均一に加熱する事ができる。尚、本例の場合には、図示しない複数の温度センサにより、上記内輪５の温度が、Ａ１変態点以上に、且つ、均一に上昇した事が検知された後、前記高周波電源１０からの高周波電力の供給を停止する。又、本例の場合には、上記内輪５の周囲に上記変形矯正型１４を配置した状態で、この内輪５をＡ１変態点以上に加熱する為、この内輪５に、円周方向に関する不均一な膨張に基づく変形が生じる事を有効に防止できる。   Therefore, in the case of this example, the output of the high-frequency power supplied to the high-frequency heating coil 9 (first heating unit 12), the heating time, etc. are appropriately set in consideration of the thickness of the inner ring 5 and the like. Thus, the entire inner ring 5 can be heated more uniformly than the A1 transformation point. In the case of this example, after it is detected by a plurality of temperature sensors (not shown) that the temperature of the inner ring 5 has risen above the A1 transformation point and uniformly, the high frequency from the high frequency power source 10 is detected. Stop supplying power. In the case of this example, in order to heat the inner ring 5 to the A1 transformation point or more with the deformation correcting die 14 disposed around the inner ring 5, the inner ring 5 is not uniform in the circumferential direction. It is possible to effectively prevent deformation based on proper expansion.

上述の様な第一工程により、上記内輪５の温度をＡ１変態点以上にまで均一に上昇させた後は、第二工程として、この内輪５を前記第二の加熱部１３により加熱する。この為に本例の場合には、図１の（Ａ）から（Ｂ）に示す状態まで、前記ワーク支持装置１１を下降させて、上記変形矯正型１４の内側から上記内輪５を抜き出す。この際必要に応じてこの内輪を、図示しないプッシャにより下方に押す。そして、この内輪５を、上記第二の加熱部１３の内径側に、この第二の加熱部１３と同心に配置する。この状態で、前記内輪軌道４が、全幅に亙り、この第二の加熱部１３に対向し、これら内輪軌道４と第二の加熱部１３との間には、全周に亙り、前記クリアランスＣ２が存在する。   After the temperature of the inner ring 5 is uniformly raised to the A1 transformation point or higher by the first step as described above, the inner ring 5 is heated by the second heating unit 13 as a second step. For this reason, in the case of this example, the work support device 11 is lowered from the state shown in FIGS. 1A to 1B and the inner ring 5 is extracted from the inside of the deformation correcting die 14. At this time, if necessary, the inner ring is pushed downward by a pusher (not shown). The inner ring 5 is arranged on the inner diameter side of the second heating unit 13 concentrically with the second heating unit 13. In this state, the inner ring raceway 4 extends over the entire width, opposes the second heating unit 13, and between the inner ring raceway 4 and the second heating unit 13, extends over the entire circumference, and the clearance C2 Exists.

この様にして、上記内輪軌道４を上記第二の加熱部１３に対向させた後は、上記高周波電源１０から前記高周波加熱コイル９（第二の加熱部１３）に、前述した第一工程で、この高周波加熱コイル９に供給した高周波電力と同一周波数の高周波電力を供給する。即ち、高周波電力の供給を再開する。これにより、上記第一の加熱部１２の場合と同様に、上記第二の加熱部１３の周囲に交番電力を発生させて、上記内輪５を誘導加熱する。   In this way, after the inner ring raceway 4 is opposed to the second heating unit 13, the high frequency power source 10 transfers the high frequency heating coil 9 (second heating unit 13) to the first step described above. The high frequency power having the same frequency as the high frequency power supplied to the high frequency heating coil 9 is supplied. That is, the supply of high frequency power is resumed. As a result, as in the case of the first heating unit 12, alternating power is generated around the second heating unit 13 to inductively heat the inner ring 5.

この様な本例の第二工程では、上記第二の加熱部１３と上記内輪軌道４との間のクリアランスＣ２（＝１／５×Ｃ１）が小さい為、上述した第一工程の場合とは反対に、上記内輪５に生じる温度勾配は大きくなる。この為、上記内輪軌道４の表層部のみを高温で加熱する事ができる。従って、本例の場合には、残留オーステナイト量を増加させようとする表層部の深さ等を考慮して、上記高周波加熱コイル９に供給する高周波電力の出力（投入電力）、加熱時間等を適宜設定する事で、上記内輪軌道４の表層部（例えば表面から１００μｍの範囲）以外の部分の温度を、前述した第一工程で上昇した、Ａ１変態点を少しだけ越えた程度に抑えた状態で、この表層部の温度のみを、十分な量の残留オーステナイトを確保する為に必要な温度（例えば９００℃以上）にまで上昇させる事ができる。
そして、図示しない複数のセンサにより、上記内輪軌道４の表層部の温度が、Ａ１変態点を十分に超える温度にまで達した事が検知されたならば、上記高周波電源１０からの高周波電力の供給を停止する。 In such a second step of this example, the clearance C2 (= 1/5 × C1) between the second heating unit 13 and the inner ring raceway 4 is small. On the contrary, the temperature gradient generated in the inner ring 5 increases. For this reason, only the surface layer portion of the inner ring raceway 4 can be heated at a high temperature. Therefore, in the case of this example, considering the depth of the surface layer portion to increase the amount of retained austenite, etc., the output (input power) of the high frequency power supplied to the high frequency heating coil 9, the heating time, etc. By appropriately setting, the temperature of the portion other than the surface layer portion of the inner ring raceway 4 (for example, a range of 100 μm from the surface) is suppressed to a level slightly exceeding the A1 transformation point raised in the first step described above. Thus, only the temperature of the surface layer portion can be raised to a temperature (for example, 900 ° C. or higher) necessary for securing a sufficient amount of retained austenite.
If it is detected by a plurality of sensors (not shown) that the temperature of the surface layer portion of the inner ring raceway 4 has reached a temperature sufficiently exceeding the A1 transformation point, the supply of high-frequency power from the high-frequency power source 10 is performed. To stop.

上述の様な第二工程を終えた後は、前記ワーク支持装置１１を更に下降させる等して、上記内輪５を上記第二の加熱部１３の内側から取り出す。そして、この内輪５を、液体又は高圧ガスを用いた噴射冷却により急速冷却し、焼入れする。尚、この場合に、前記変形矯正型１４を上記内輪５に外嵌した状態で冷却する事もできる。この様に、この変形矯正型１４を外嵌して冷却作業を行えば、冷却時の変形を有効に防止する事ができる。そして、この様な冷却作業が済んだ後は、例えば１５０〜２００℃で焼戻し処理を施す。尚、この焼戻し処理は、前記第一の加熱部１２を利用して行う事もできる。   After finishing the second step as described above, the inner ring 5 is taken out from the inside of the second heating unit 13 by further lowering the work support device 11. And this inner ring | wheel 5 is rapidly cooled by the injection cooling using a liquid or high pressure gas, and it hardens. In this case, the deformation correction die 14 can be cooled in a state of being fitted on the inner ring 5. In this way, if the deformation correction mold 14 is externally fitted and the cooling operation is performed, deformation during cooling can be effectively prevented. And after such a cooling operation is completed, a tempering process is performed, for example at 150-200 degreeC. In addition, this tempering process can also be performed using said 1st heating part 12. FIG.

以上の様な本例の熱処理方法によれば、上記内輪５全体を、Ａ１変態点以上に、且つ、均一に（Ａ１変態点を大きく越えない程度に）加熱する事ができると共に、この内輪５のうちの内輪軌道４の表層部のみを、他の部分に比べて高温で加熱する事ができる。従って、本例の場合には、この内輪軌道４の表層部の残留オーステナイト量を２０〜５０容量％にまで増加させる事ができるだけでなく、芯部を含む、上記内輪軌道４の表層部以外の部分の残留オーステナイト量の増加を抑えて、上記内輪５全体の平均残留オーステナイト量を１０容量％以下に抑える事ができる。更に、本例の場合には、前述した第一工程によって、上記内輪５全体の組織をオーステナイト化する事ができる為、この内輪５の芯部の靱性を確保する事ができて、この芯部の強度を十分に確保できる。   According to the heat treatment method of the present example as described above, the entire inner ring 5 can be heated to a temperature equal to or higher than the A1 transformation point (so as not to greatly exceed the A1 transformation point). Of these, only the surface layer portion of the inner ring raceway 4 can be heated at a higher temperature than other portions. Therefore, in the case of this example, not only the amount of retained austenite in the surface layer portion of the inner ring raceway 4 can be increased to 20 to 50% by volume, but also the portion other than the surface layer portion of the inner ring raceway 4 including the core portion. The increase in the amount of retained austenite in the portion can be suppressed, and the average amount of retained austenite in the entire inner ring 5 can be suppressed to 10% by volume or less. Further, in the case of this example, the entire structure of the inner ring 5 can be austenitized by the first step described above, so that the toughness of the core part of the inner ring 5 can be ensured. Sufficient strength can be secured.

そして、この様な本例の熱処理方法を施した内輪５は、内輪軌道４の表層部の残留オーステナイト量が十分に多くなる為、異物混入潤滑環境下に於いても、この内輪軌道４に早期剥離が発生する事を防止できて、転がり疲れ寿命の延長を図れる。更に、芯部を含む、上記内輪軌道４の表層部以外の部分の残留オーステナイト量を過度に多くせずに済む為、寸法安定性に優れたものとなる。   The inner ring 5 subjected to such a heat treatment method of this example has a sufficiently large amount of retained austenite in the surface layer portion of the inner ring raceway 4, so even in a lubrication environment containing foreign matter, It is possible to prevent peeling and to extend the rolling fatigue life. Furthermore, since it is not necessary to excessively increase the amount of retained austenite in the portion other than the surface layer portion of the inner ring raceway 4 including the core portion, the dimensional stability is excellent.

尚、本例の熱処理方法を実施する場合に、高周波加熱コイル９を構成する第一の加熱部１２に関しては、必ずしも内輪５の外径側に配置する必要はなく、この内輪５の内径側に配置する事もできる。但し、第二の加熱部１３に関しては、内輪軌道４に対向させる必要上、上記内輪５の外径側に必ず配置する。又、外輪３（図２参照）を対象として本例の熱処理方法を施す場合には、上述した内輪５の場合と同様の理由で、少なくとも第二の加熱部１３に関しては、上記外輪３の内径側に配置する必要があるが、第一の加熱部１２に関しては、この外輪３の外径側或は内径側の何れに配置しても良い。   When the heat treatment method of this example is carried out, the first heating part 12 constituting the high-frequency heating coil 9 is not necessarily arranged on the outer diameter side of the inner ring 5. It can also be arranged. However, the second heating unit 13 is necessarily arranged on the outer diameter side of the inner ring 5 because it is necessary to face the inner ring raceway 4. Further, when the heat treatment method of this example is applied to the outer ring 3 (see FIG. 2), at least the inner diameter of the outer ring 3 with respect to the second heating unit 13 for the same reason as the case of the inner ring 5 described above. The first heating unit 12 may be disposed on either the outer diameter side or the inner diameter side of the outer ring 3.

又、浸炭処理或は浸炭窒化処理によって、表層部に浸炭層或は浸炭窒化層が形成された内輪５（或は外輪３）を対象に本例の熱処理方法を施す場合にも、使用する高周波加熱コイル９等の各装置の構成、及び、基本的な工程の流れに就いては、上述した実施の形態の１例の場合と同様である。但し、浸炭層或は浸炭窒化層のうちで、軌道面の表層部以外の部分の残留オーステナイト量の増加を抑える面からは、第一工程での加熱温度を、Ａ１変態点以上でも、より低温（例えば７５０〜８００℃程度）に規制する。   The high frequency used also when the heat treatment method of this example is applied to the inner ring 5 (or the outer ring 3) in which the carburized layer or the carbonitrided layer is formed on the surface layer by carburizing or carbonitriding. About the structure of each apparatus, such as the heating coil 9, and the flow of a basic process, it is the same as that of the case of one example of embodiment mentioned above. However, from the aspect of suppressing the increase in the amount of retained austenite in the carburized layer or carbonitrided layer other than the surface layer portion of the raceway surface, the heating temperature in the first step is lower than the A1 transformation point. (For example, about 750 to 800 ° C.).

更に、上述した実施の形態の１例では、上記内輪５として、外周面に１つの内輪軌道４を有するものを対象に熱処理を施す場合に就いて説明したが、本発明は、この様な、単列ラジアル軸受用の軌道輪のみを対象にするものではない。即ち、本発明は、２以上の軌道面を有するラジアル軸受用軌道輪を対象に行う事もできる。この場合には、軌道面の数と同じ数だけ、第二の加熱部を有する高周波加熱コイルを使用する。   Furthermore, in the example of the above-described embodiment, the case where the inner ring 5 is subjected to heat treatment for the one having the inner ring raceway 4 on the outer peripheral surface has been described. It is not intended only for races for single row radial bearings. That is, the present invention can also be performed on a radial bearing race ring having two or more raceway surfaces. In this case, the same number of high-frequency heating coils having the second heating unit as the number of raceway surfaces are used.

本発明の効果を確認する為に行った実験に就いて、以下、説明する。この実験では、先ず、ＪＩＳ Ｇ ４８０５に規定される高炭素クロム軸受鋼（ＳＵＪ２）と、ＪＩＳ Ｇ ４０５１に規定される機械構造用炭素鋼鋼材（Ｓ４５Ｃ）との２種類の鋼材から、ラジアル玉軸受用外輪（外径１２０mm、径方向厚さ４．０mm、軸方向幅１５mm）を合計９個作成した。そして、ＳＵＪ２製のラジアル玉軸受用外輪（６個）のうち、２個のラジアル玉軸受用外輪には、浸炭窒化処理を施した。又、Ｓ４５Ｃ製のラジアル玉軸受用外輪（３個）に就いては、総てに浸炭窒化処理を施した。そして、これらＳＵＪ２製のラジアル玉軸受用外輪（浸炭窒化処理ナシ４個、浸炭窒化処理アリ２個）と、Ｓ４５Ｃ製のラジアル玉軸受用外輪（総てに浸炭窒化処理アリ）との合計９個のラジアル玉軸受用外輪を試料として、表１に記載した条件で熱処理を施し、軌道面の表層部に存在する残留オーステナイト量と、軌道輪全体の平均残留オーステナイト量とに及ぼす影響を評価した。   An experiment conducted for confirming the effect of the present invention will be described below. In this experiment, first, a radial ball bearing is produced from two types of steel materials, a high carbon chromium bearing steel (SUJ2) defined in JIS G 4805 and a carbon steel material for mechanical structure (S45C) defined in JIS G 4051. A total of nine outer rings (outer diameter 120 mm, radial thickness 4.0 mm, axial width 15 mm) were prepared. Of the radial ball bearing outer rings (six) made of SUJ2, two radial ball bearing outer rings were carbonitrided. Further, all the S45C radial ball bearing outer rings (three) were carbonitrided. A total of nine of these SUJ2 radial ball bearing outer rings (4 carbonitriding pears, 2 carbonitriding ants) and S45C radial ball bearing outer rings (all carbonitriding ants) Using the outer ring for a radial ball bearing as a sample, heat treatment was performed under the conditions shown in Table 1, and the effect on the amount of retained austenite existing in the surface layer portion of the raceway surface and the average amount of retained austenite of the entire raceway ring was evaluated.

尚、残留オーステナイト量の測定は、上記表１に記載した条件の熱処理を施した後、冷却し、１８０℃×２ｈｒの焼戻し処理を施した後に行った。具体的には、軌道面の表層部の残留オーステナイト量はＸ線回折法により測定し、平均残留オーステナイト量は、上記各試料の円周方向の一部を直径方向に切断した後、軌道面から深さ方向（直径方向外方）に１０等配した各点に存在する残留オーステナイト量を求め、これらを平均する事により求めた。尚、上記表１中、本発明の技術的範囲から外れる数値等に就いてはアンダーラインを付した。   The amount of retained austenite was measured after heat treatment under the conditions described in Table 1 above, followed by cooling and tempering at 180 ° C. × 2 hr. Specifically, the amount of retained austenite in the surface layer portion of the raceway surface is measured by an X-ray diffraction method, and the average amount of retained austenite is measured from the raceway surface after cutting a part in the circumferential direction of each sample in the diameter direction. The amount of retained austenite present at each of the 10 points equally distributed in the depth direction (outward in the diameter direction) was determined and averaged. In Table 1, numerical values that deviate from the technical scope of the present invention are underlined.

Figure 2009270173
Figure 2009270173

実験結果を表す表１から明らかな通り、クリアランスＣ１及びＣ２を、Ｃ１＞Ｃ２の関係を満たす様に規制した、実施例１〜６の場合には、軌道面の表層部の残留オーステナイト量を、転がり疲れ寿命の延長を十分に図れる値である、２５容量％以上に増やす事ができる事が確認できた。しかも、この場合に、軌道輪全体の平均残留オーステナイト量を、寸法安定性を十分に確保できる値である、１０容量％以下に抑えられる事も確認できた。   As is clear from Table 1 showing the experimental results, the clearances C1 and C2 were regulated so as to satisfy the relationship of C1> C2, and in the case of Examples 1 to 6, the amount of retained austenite in the surface layer portion of the raceway surface was It was confirmed that the rolling fatigue life can be increased to 25% by volume or more, which is a value that can sufficiently extend the rolling fatigue life. In addition, in this case, it was also confirmed that the average retained austenite amount of the entire race was suppressed to 10% by volume or less, which is a value that can sufficiently secure dimensional stability.

これに対して、比較例１の場合には、本発明の第一工程に相当する、第一の加熱部による加熱は行っているが、第二工程に相当する、第二の加熱部による加熱を行っていない。この為、軌道面の表層部に十分な量の残留オーステナイトが得られていない。   On the other hand, in the case of the comparative example 1, although the heating by the 1st heating part equivalent to the 1st process of this invention is performed, the heating by the 2nd heating part equivalent to a 2nd process is performed. Not done. For this reason, a sufficient amount of retained austenite is not obtained in the surface layer portion of the raceway surface.

又、比較例２の場合には、実施例１〜６の場合に比べて、クリアランスＣ１が小さく、このクリアランスＣ１をクリアランスＣ２と同じ大きさに設定している為、第一の加熱部による加熱によって、ラジアル玉軸受用外輪に温度勾配が生じ、芯部の残留オーステナイト量が必要以上に多くなったと考えられる。この為、軌道輪全体の平均残留オーステナイト量が、実施例１〜６の場合に比べて増加している。   In the case of the comparative example 2, the clearance C1 is smaller than that in the case of the first to sixth embodiments, and the clearance C1 is set to the same size as the clearance C2. Therefore, the heating by the first heating unit is performed. As a result, a temperature gradient was generated in the outer ring for the radial ball bearing, and the amount of retained austenite in the core portion was considered to have increased more than necessary. For this reason, the average retained austenite amount of the entire race is increased as compared with the cases of Examples 1-6.

更に、比較例３の場合には、本発明の第一、第二工程による熱処理ではなく、炉内雰囲気中で焼入れ処理を施している為、軌道面の表層部だけでなく、芯部を含む、軌道輪全体の残留オーステナイト量が増加したと考えられる。この為、やはり軌道輪全体の平均残留オーステナイト量が、上述した実施例１〜６の場合に比べて増加している。   Furthermore, in the case of Comparative Example 3, since the quenching treatment is performed in the furnace atmosphere, not the heat treatment in the first and second steps of the present invention, not only the surface layer portion of the raceway surface but also the core portion is included. It is considered that the amount of retained austenite of the entire race was increased. For this reason, the average retained austenite amount of the entire race is also increased as compared with the cases of Examples 1 to 6 described above.

本発明の実施の形態の１例を示す概略構成図。1 is a schematic configuration diagram illustrating an example of an embodiment of the present invention. 本発明の熱処理方法の対象となる軌道輪を組み込んだラジアル軸受の１例を示す断面図。Sectional drawing which shows an example of the radial bearing which incorporated the bearing ring used as the object of the heat processing method of this invention.

符号の説明Explanation of symbols

１ ラジアル玉軸受
２ 外輪軌道
３ 外輪
４ 内輪軌道
５ 内輪
６ 玉
７ 保持器
８ 高周波加熱装置
９ 高周波加熱コイル
１０ 高周波電源
１１ ワーク支持装置
１２ 第一の加熱部
１３ 第二の加熱部
１４ 変形矯正型 DESCRIPTION OF SYMBOLS 1 Radial ball bearing 2 Outer ring raceway 3 Outer ring 4 Inner ring raceway 5 Inner ring 6 Ball 7 Cage 8 High frequency heating device 9 High frequency heating coil 10 High frequency power supply 11 Work support device 12 First heating unit 13 Second heating unit 14 Deformation correction type

Claims (3)

ラジアル軸受用軌道輪を高周波加熱コイルにより加熱した後、冷却し、焼戻し処理を施す、ラジアル軸受用軌道輪の熱処理方法であって、上記高周波加熱コイルが、少なくとも互いに直径の異なる第一の加熱部と第二の加熱部とを有する、２ターン以上の高周波加熱コイルであって、上記ラジアル軸受用軌道輪を、上記第一の加熱部及び上記第二の加熱部の内径側或は外径側にこれら第一、第二の加熱部と同心にそれぞれ配置した状態で、このうちの第一の加熱部と上記ラジアル軸受用軌道輪とのクリアランスＣ１と、上記第二の加熱部とこのラジアル軸受用軌道輪のうちの軌道面とのクリアランスＣ２とが、Ｃ１＞Ｃ２の関係を満たすものであり、このラジアル軸受用軌道輪を、上記第一の加熱部の内径側或は外径側にこの第一の加熱部と同心に配置した後、このラジアル軸受用軌道輪を、上記高周波加熱コイルに所定の周波数を有する高周波電力を供給して加熱する第一工程と、上記ラジアル軸受用軌道輪を、上記第二の加熱部の内径側或は外径側にこの第二の加熱部と同心に配置した後、このラジアル軸受用軌道輪を、上記第一工程で上記高周波加熱コイルに供給した高周波電力と同一周波数の高周波電力をこの高周波加熱コイルに供給して加熱する第二工程とを備える事を特徴とするラジアル軸受用軌道輪の熱処理方法。   A radial bearing race ring heat treatment method in which a radial bearing race ring is heated by a high-frequency heating coil, then cooled and tempered, wherein the high-frequency heating coil is at least a first heating section having a diameter different from each other. A high-frequency heating coil having two or more turns, wherein the radial bearing race is connected to an inner diameter side or an outer diameter side of the first heating section and the second heating section. Are arranged concentrically with the first and second heating sections, respectively, and the clearance C1 between the first heating section and the radial bearing raceway, the second heating section and the radial bearing. Clearance C2 with the raceway surface of the bearing ring satisfies the relationship of C1> C2, and this radial bearing raceway is connected to the inner diameter side or the outer diameter side of the first heating section. With the first heating section After the arrangement in the center, the radial bearing race is heated by supplying high frequency power having a predetermined frequency to the high frequency heating coil, and the radial bearing race is heated by the second heating. After being arranged concentrically with the second heating part on the inner diameter side or outer diameter side of the part, the radial bearing race is connected to the high frequency power having the same frequency as the high frequency power supplied to the high frequency heating coil in the first step. A heat treatment method for a bearing ring for a radial bearing, comprising: a second step of supplying electric power to the high-frequency heating coil to heat it. 第一の加熱部とラジアル軸受用軌道輪との間に非磁性材製の変形矯正型を配置し、このラジアル軸受用軌道輪の形状を矯正しつつ、このラジアル軸受用軌道輪を加熱する、請求項１に記載したラジアル軸受用軌道輪の熱処理方法。   A non-magnetic deformation correction mold is disposed between the first heating unit and the radial bearing raceway, and the radial bearing raceway is heated while correcting the shape of the radial bearing raceway. The heat processing method of the bearing ring for radial bearings described in Claim 1. 軌道面の表層部の残留オーステナイト量を２０〜５０容量％とし、軌道輪全体の平均残留オーステナイト量を１０容量％以下とする、請求項１〜２のうちの何れか１項に記載したラジアル軸受用軌道輪の熱処理方法。   The radial bearing according to any one of claims 1 to 2, wherein a retained austenite amount of a surface layer portion of the raceway surface is set to 20 to 50% by volume, and an average retained austenite amount of the entire raceway is set to 10% by volume or less. Heat treatment method for bearing rings.
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JP2011256977A (en) * 2010-06-11 2011-12-22 Ntn Corp Deep groove ball bearing
JP2012149304A (en) * 2011-01-19 2012-08-09 Nsk Ltd Heat treatment method of track member
JP2014238153A (en) * 2013-06-10 2014-12-18 Ntn株式会社 Taper roller bearing
CN113597036A (en) * 2021-07-30 2021-11-02 重庆长安新能源汽车科技有限公司 Low-cost uniform heating device for motor heat jacket
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CN114196819A (en) * 2021-10-27 2022-03-18 内蒙古工业大学 Bearing ring heat treatment deformation control method

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011256977A (en) * 2010-06-11 2011-12-22 Ntn Corp Deep groove ball bearing
JP2012149304A (en) * 2011-01-19 2012-08-09 Nsk Ltd Heat treatment method of track member
JP2014238153A (en) * 2013-06-10 2014-12-18 Ntn株式会社 Taper roller bearing
CN105283684A (en) * 2013-06-10 2016-01-27 Ntn株式会社 Tapered roller bearing
US9816557B2 (en) 2013-06-10 2017-11-14 Ntn Corporation Tapered roller bearing
CN113597036A (en) * 2021-07-30 2021-11-02 重庆长安新能源汽车科技有限公司 Low-cost uniform heating device for motor heat jacket
CN113597035A (en) * 2021-07-30 2021-11-02 重庆长安新能源汽车科技有限公司 Efficient uniform heating device for motor heat jacket
CN113597036B (en) * 2021-07-30 2023-05-23 重庆长安新能源汽车科技有限公司 Low-cost uniform heating device for motor hot jacket
CN113597035B (en) * 2021-07-30 2023-05-26 重庆长安新能源汽车科技有限公司 Efficient uniform heating device for motor hot jacket
CN114196819A (en) * 2021-10-27 2022-03-18 内蒙古工业大学 Bearing ring heat treatment deformation control method
CN114196819B (en) * 2021-10-27 2023-08-08 内蒙古工业大学 Bearing ring heat treatment deformation control method

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