JP4075364B2 - Cylindrical roller bearing - Google Patents

Cylindrical roller bearing Download PDF

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JP4075364B2
JP4075364B2 JP2001374494A JP2001374494A JP4075364B2 JP 4075364 B2 JP4075364 B2 JP 4075364B2 JP 2001374494 A JP2001374494 A JP 2001374494A JP 2001374494 A JP2001374494 A JP 2001374494A JP 4075364 B2 JP4075364 B2 JP 4075364B2
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cylindrical roller
crowning
roller bearing
cylindrical
raceway surface
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JP2003172360A (en
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敏弘 川口
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JTEKT Corp
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JTEKT Corp
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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
    • F16C23/00—Bearings for exclusively rotary movement adjustable for aligning or positioning
    • F16C23/06—Ball or roller bearings
    • F16C23/08—Ball or roller bearings self-adjusting
    • F16C23/088—Ball or roller bearings self-adjusting by means of crowning
    • 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
    • F16C33/34—Rollers; Needles
    • 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
    • F16C2240/00—Specified values or numerical ranges of parameters; Relations between them
    • F16C2240/40—Linear dimensions, e.g. length, radius, thickness, gap
    • F16C2240/50—Crowning, e.g. crowning height or crowning radius
    • 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
    • F16C2240/00—Specified values or numerical ranges of parameters; Relations between them
    • F16C2240/40—Linear dimensions, e.g. length, radius, thickness, gap
    • F16C2240/54—Surface roughness

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、転動体としての複数の円筒ころを有する円筒ころ軸受、特に当該軸受が支持する支持対象部品を内外輪の少なくとも一方として用いた円筒ころ軸受に関する。
【０００２】
【従来の技術及び発明が解決しようとする課題】
例えばトランスミッションのカウンターシャフトを回転自在に支持する円筒ころ軸受には、ハウジングに固定された外輪と内輪軌道面としての上記シャフト表面との間で複数の円筒ころを転動させるシャフトダイレクトタイプのものが用いられている。このような円筒ころ軸受では、一般的に、円筒ころの有効軌道部の両端部にクラウニングを形成することにより、当該両端部のシャフトとの接触部での急峻な面圧ピーク（エッジロード）を抑えている。
ところが、上記のような従来の円筒ころ軸受では、円筒ころの上記シャフト（支持対象部品）への組付状態やシャフトの加工精度などに起因して、上記接触部で潤滑不良を発生することがあった。この結果、上記両端部などの円筒ころ表面が傷付いたり、シャフトに表層剥離などの表面損傷が生じたりして早期不具合を発生するという問題があった。
【０００３】
上記のような従来の問題点に鑑み、本発明は、円筒ころ及び支持対象部品に表層剥離などの表面損傷が発生するのを抑制することができ、よって軸受及び支持対象部品の長寿命化を図ることができる円筒ころ軸受を提供することを目的とする。
【０００４】
【課題を解決するための手段】
本発明の円筒ころ軸受は、軸受用鋼からなる複数の円筒ころと、これらの円筒ころが転動する内輪軌道面及び外輪軌道面の少なくとも一方の軌道面を支持対象部品の表面により構成した円筒ころ軸受であって、
前記複数の各円筒ころの有効軌道部の端部に、クラウニングを施したクラウニング部を形成し、
前記支持対象部品の軸中心に対して、前記内輪軌道面及び前記外輪軌道面の他方の軌道面の軸中心が傾いた状態で発生する油膜切れに起因する前記円筒ころ又は前記支持対象部品の表面損傷を抑制するべく、超仕上砥石によって、前記クラウニング部の表面の粗さを、当該クラウニング部を除く断面直線状の前記有効軌道部の表面の粗さと同等以上にしたことを特徴とするものである（請求項１）。
【０００５】
上記のように構成された円筒ころ軸受における円筒ころでは、上記クラウニング部の表面粗さを当該クラウニング部以外の有効軌道部の表面粗さと同等以上にすることにより、本発明の発明者は表面剥離などの表面損傷が円筒ころ及び支持対象部品に発生するのを抑制できることを見出した。
【０００６】
また、上記ころ軸受（請求項１）において、前記クラウニング部の表面の十点平均粗さを０．４μｍ以下とすることが好ましい（請求項２）。さらに好ましくは、さらに中心線平均粗さを０．０８μｍ以下とすることが好ましい。このようにクラウニング部の表面の十点平均粗さを０．４μｍ以下とすること、あるいはさらに中心線平均粗さを０．０８μｍ以下とすることによって、本発明の発明者は上記表面損傷をより効果的に抑えられることを見出した。
【０００７】
【発明の実施の形態】
以下、本発明のころ軸受の好ましい実施形態について、図面を参照しながら説明する。尚、下記の説明では、シャフトダイレクトタイプの円筒ころ軸受を構成した場合を例示して説明する。
図１は、本発明の一実施形態に係る円筒ころ軸受の断面図である。図２（ａ）は図１に示した円筒ころの要部構成を示す拡大図であり、（ｂ）は（ａ）のIIｂ線で囲んだ部分の拡大図である。尚、図２においては、軸方向（横方向）倍率に比べ径方向（縦方向）倍率を高倍率（２００倍）にしている。以下図３及び図４も同様にしている。
図１において、当該軸受は、外輪１と、内輪としてのシャフト２と、これらの内外輪間に転動自在に配列された複数の円筒ころ３とを備えている。上記外輪１は、軸受鋼や浸炭鋼等の軸受用鋼により構成されており、図示しないハウジングなどに固定されている。また、上記シャフト２は、その表面硬度ＨＲＣが５７〜６０程度の例えば浸炭鋼や炭素鋼に適宜熱処理や高周波焼入れなどで表面硬化処理されたものにより構成されている。
【０００８】
上記円筒ころ３は、例えば軸受用鋼により構成されたものであり、その硬度ＨＲＣが６０〜６７となるように耐熱処理が施されている。この円筒ころ３は、図示しない周知の保持器によって保持された状態または保持器なしの総ころ形式の状態で、油膜を介して外輪１の外輪軌道面１ａ及び内輪軌道面としてのシャフト２の外周面２ａ上を転動する。また、円筒ころ３には、その両側面３ａの間に、上記外輪軌道面１ａ及びシャフト外周面２ａに転がり接触する有効軌道部３ｂが設けられている。
【０００９】
詳細には、図２（ａ）に示すように、円筒ころ３の幅方向（図の左右方向）両端部には、所定の面取りＲ寸法にて形成され、有効軌道部３ｂと各側面３ａとに連続する面取り部３ｃが設けられている。
上記有効軌道部３ｂには、断面直線状に形成された平坦部３ｂ１と、当該有効軌道部３ｂの両端部に設けられ、エッジロードを抑制するためのクラウニング部３ｂ２とが設けられている。このクラウニング部３ｂ２は、例えば所定の曲率からなる断面円弧状のクラウニングを有効軌道部３ｂの両端部に施すことにより形成されたものであり、平坦部３ｂ１と面取り部３ｃとに連続するよう設けられている。
【００１０】
また、上記平坦部３ｂ１及びクラウニング部３ｂ２の表面は、円筒ころ３がセンターレス研削盤にスルーフィードされることにより、当該研削盤にセットされた超仕上砥石で所望の粗さに超仕上加工されている。具体的には、平坦部３ｂ１の表面は、０．４μｍ程度の十点平均粗さＲｚまたは０．０８μｍ程度の中心線平均粗さＲａに仕上げられている。また、図２（ｂ）に示すクラウニング部３ｂ２の表面は、上記研削盤にスルーフィードされる時間を長くすることにより、上記平坦部３ｂ１と同等以上の粗さ、つまり十点平均粗さＲｚが０．４μｍ以下または０．０８μｍ以下の中心線平均粗さＲａに仕上げられている。尚、平坦部３ｂ１とクラウニング部３ｂ２との接続箇所などにばり等が生じる場合は、上記超仕上加工の後にバレル加工やタンブラー加工を実施し、ばり等を除去することが好ましい。
【００１１】
ここで、本発明の発明者が実施した耐久試験について、図１〜図４及び表１を参照して説明する。
この耐久試験では、本発明相当品の試験品１〜４と従来相当品の比較品１，２とを用意して、上記平坦部３ｂ１及びクラウニング部３ｂ２の表面粗さを変化させたときの効果を確認した。上記試験品１，２は図２（ａ）に示した平坦部３ｂ１及びクラウニング部３ｂ２の十点平均粗さＲｚをそれぞれ０．４μｍ及び０．２μｍまたは中心線平均粗さＲａをそれぞれ０．０８μｍ及び０．０４μｍとしたものであり、試験品３，４は同平坦部３ｂ１及びクラウニング部３ｂ２の十点平均粗さＲｚをそれぞれ０．４μｍ及び０．４μｍまたは中心線平均粗さＲａをそれぞれ０．０８μｍ及び０．０８μｍとしたものである。また、比較品１，２は、図４（ａ）及び（ｂ）に示すように、円筒ころ４の各側面４ａに連続する、上記面取り部３ｃと同一の面取り部４ｃを当該ころの左右端部に設け、さらに面取り部４ｃの間に、十点平均粗さＲｚをそれぞれ０．４μｍ及び０．６μｍまたは中心線平均粗さＲａをそれぞれ０．０８μｍ及び０．１２μｍとした平坦部４ｂ１及びクラウニング部４ｂ２からなる有効軌道部４ｂを設けたものである。
【００１２】
また、この耐久試験では、円筒ころ３，４及びシャフト２に表面損傷が生じやすいように、シャフト２の軸中心に対して外輪１の軸中心を１０分傾かせた状態でシャフト２に円筒ころ３，４及び外輪１を組付け、かつ外輪１に１４１００Ｎ（１４３８ｋｇｆ）のラジアル荷重を与えた状態で、シャフト２を４０００ｒｐｍで連続回転させた。そして、表１に示すように、これら構成部品に表面損傷が生じるまでの運転時間を確認し、さらに累積破損確率として、１０％の製品が破損するまでのＢ10寿命時間を求めた。尚、表１において、試験数は各組合わせサドンデス試験２個組を２セットで行っている。
【００１３】
【表１】

Figure 0004075364
【００１４】
表１に示すように、上記Ｂ10寿命時間は、試験品１，２が一番長く、ついで試験品３，４及び比較品１，２の順番となった。
また、図３（ａ）及び（ｂ）に示すように、例えば試験品１，２では、円筒ころ３の表面はほとんど傷付いておらず、シャフト２の外周面２ａにわずかに内部起点剥離が生じていた。この内部起点剥離は、シャフト２に対して外輪１及び円筒ころ３を傾かせた状態で組付けたことによるものと考察され、実製品では転がり疲労による早期不具合とならないものである。
一方、比較品１，２では、上記試験品１，２に比べて、短い時間で油膜切れなどの潤滑不良が発生し、図４（ｄ）に示すように、シャフト２の外周面２ａには、試験品１，２に対し、表層剥離が発生していた。また、図４（ｃ）に示すように、クラウニング部４ｂ２、さらには平坦部４ｂ１の表面にも無数の傷が生じていた。
【００１５】
以上のように、本実施形態の円筒ころ軸受では、平坦部３ｂ１とこれの両端に連続するクラウニング部３ｂ２とからなる有効軌道部３ｂにおいて、クラウニング部３ｂ２の表面粗さを、当該クラウニング部３ｂ２以外の有効軌道部３ｂ（すなわち、平坦部３ｂ１）の表面粗さと同等以上に仕上げることにより、表面剥離などの表面損傷がころ及び支持対象部品に発生するのを抑制できることが確認された。また、上記試験品３，４と比較品１，２との試験結果から明らかなように、クラウニング部３ｂ２の十点平均粗さＲｚを０．４μｍ以下または中心線平均粗さＲａを０．０８μｍ以下とすることにより、上記表面損傷をより効果的に抑制できることが確認された。
【００１６】
尚、上記の説明では、シャフトダイレクトタイプの円筒ころ軸受に適用した場合について説明したが、本発明はクラウニング部３ｂ２の表面の粗さを、当該クラウニング部３ｂ２を除く有効軌道部３ｂの表面の粗さと同等以上にしたものであれば何等限定されない。また、円筒ころが転動する内輪軌道面及び外輪軌道面の少なくとも一方の軌道面を支持対象部品の表面により構成した円筒ころ軸受に適用することができる。例えばローラ圧延機において、外輪軌道面としてのロールの内周面に、円筒ころを直接的に転動させる円筒ころ軸受に適用することができる。
【００１７】
また、上記の説明では、円筒ころ３の有効軌道部３ｂの両端部にクラウニング部３ｂ２を形成した場合について説明したが、片方の端部のみにクラウニング部を形成したころにも適用することができる。
また、上記の説明では、所定の曲率からなる断面円弧状のクラウニングを施したクラウニング部３ｂ２について説明したが、クラウニングの形状は上記断面円弧状に限定されない。
【００１８】
【発明の効果】
以上のように構成された本発明は以下の効果を奏する。
請求項１の円筒ころ軸受によれば、表面剥離などの表面損傷が円筒ころ及び支持対象部品に発生するのを抑制できるので、円筒ころ及び支持対象部品の耐久性を向上させ、当該軸受及び支持対象部品の長寿命化を図ることができる。
【００１９】
請求項２の円筒ころ軸受によれば、上記表面損傷をより効果的に抑えることができるので、円筒ころ及び支持対象部品の耐久性をさらに向上させて、当該軸受及び支持対象部品の寿命もさらに延ばすことができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る円筒ころ軸受の断面図である。
【図２】（ａ）は図１に示した円筒ころの要部構成を示す拡大図であり、（ｂ）は（ａ）のIIｂ線で囲んだ部分の拡大図である。
【図３】図１に示した円筒ころ軸受の耐久試験の結果を示す図であり、（ａ）は耐久試験後における円筒ころ表面の状態を示す図であり、（ｄ）は耐久試験後におけるシャフト表面の状態を示す図である。
【図４】上記耐久試験における比較品の試験結果を示す図であり、（ａ）は耐久試験前における比較品の円筒ころ表面の状態を示す図であり、（ｂ）は（ａ）のIVｂ線で囲んだ部分の拡大図であり、（ｃ）は耐久試験後における同円筒ころ表面の状態を示す図であり、（ｄ）は耐久試験後におけるシャフト表面の状態を示す図である。
【符号の説明】
１ 外輪
１ａ 外輪軌道面
２ シャフト（内輪としての支持対象部品）
２ａ 外周面（内輪軌道面）
３ 円筒ころ
３ｂ 有効軌道部
３ｂ２ クラウニング部[0001]
BACKGROUND OF THE INVENTION
The present invention, rolling plurality of cylindrical roller bearing with cylindrical rollers as the moving object, in particular, cylindrical roller bearing using as at least one of the inner outer ring support target component to which the bearing support.
[0002]
[Prior art and problems to be solved by the invention]
For example, a cylindrical roller bearing that rotatably supports a countershaft of a transmission includes a shaft direct type that rolls a plurality of cylindrical rollers between an outer ring fixed to a housing and the shaft surface as an inner ring raceway surface. It is used. In such a cylindrical roller bearing, generally, by forming a crowning at both ends of the effective raceway portion of the cylindrical roller, a steep surface pressure peak (edge load) at the contact portion with the shaft at both ends is obtained. It is suppressed.
However, in the conventional cylindrical roller bearing as described above, poor lubrication may occur at the contact portion due to the assembled state of the cylindrical roller to the shaft (part to be supported) or the processing accuracy of the shaft. there were. As a result, there has been a problem that the cylindrical roller surfaces such as the above-mentioned both ends are damaged, or surface damage such as surface peeling occurs on the shaft, thereby causing an early failure.
[0003]
In view of the conventional problems as described above, the present invention can suppress the occurrence of surface damage such as surface peeling on the cylindrical roller and the support target component, thereby extending the life of the bearing and the support target component. An object of the present invention is to provide a cylindrical roller bearing that can be realized.
[0004]
[Means for Solving the Problems]
Cylindrical roller bearing of the present invention includes a plurality of cylindrical rollers made of bearing steel, cylindrical these cylindrical rollers are constituted by the inner ring raceway surface and at least one of the raceway surface support target part of the surface of the outer ring raceway surface for rolling A roller bearing,
At the end of the effective track portion of each of the plurality of cylindrical rollers, a crowning portion that is crowned is formed ,
The surface of the cylindrical roller or the part to be supported due to the oil film breakage occurring when the axis center of the other raceway surface of the inner ring raceway surface and the outer ring raceway surface is inclined with respect to the axis center of the part to be supported. In order to suppress damage, the surface roughness of the crowning portion is made equal to or greater than the roughness of the surface of the effective track portion having a linear cross section excluding the crowning portion by a super finishing grindstone. (Claim 1).
[0005]
In the cylindrical rollers in the configuration is a cylindrical roller bearing as described above, the surface roughness of the crowning portion by more than equal to the surface roughness of the effective track portion other than the crowning portion, the inventor of the present invention is surface peeling It has been found that surface damage such as the above can be suppressed from occurring in the cylindrical roller and the parts to be supported.
[0006]
In the roller bearing (Claim 1), it is preferable that the ten-point average roughness of the surface of the crowning portion is 0.4 μm or less (Claim 2). More preferably, the center line average roughness is preferably 0.08 μm or less. Thus, by setting the ten-point average roughness of the surface of the crowning portion to 0.4 μm or less, or further setting the center line average roughness to 0.08 μm or less, the inventors of the present invention can further reduce the surface damage. It was found that it can be effectively suppressed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the roller bearing of the present invention will be described with reference to the drawings. In the following description, a case where a shaft direct type cylindrical roller bearing is configured will be described as an example.
FIG. 1 is a sectional view of a cylindrical roller bearing according to an embodiment of the present invention. FIG. 2A is an enlarged view showing a configuration of a main part of the cylindrical roller shown in FIG. 1, and FIG. 2B is an enlarged view of a portion surrounded by line IIb in FIG. In FIG. 2, the radial (longitudinal) magnification is set to a high magnification (200 times) compared to the axial (lateral) magnification. The same applies to FIGS. 3 and 4 below.
In FIG. 1, the bearing includes an outer ring 1, a shaft 2 as an inner ring, and a plurality of cylindrical rollers 3 arranged so as to be able to roll between the inner and outer rings. The outer ring 1 is made of bearing steel such as bearing steel or carburized steel, and is fixed to a housing or the like (not shown). The shaft 2 is made of, for example, carburized steel or carbon steel having a surface hardness HRC of about 57 to 60, which is appropriately hardened by heat treatment or induction hardening.
[0008]
The cylindrical roller 3 is made of, for example, bearing steel and is heat-treated so that its hardness HRC is 60 to 67. The cylindrical roller 3 is held by a well-known cage (not shown) or in a full roller type without a cage, and the outer circumference of the outer ring raceway surface 1a of the outer ring 1 and the outer circumference of the shaft 2 as the inner ring raceway surface through an oil film. Roll on the surface 2a. Further, the cylindrical roller 3 is provided with an effective raceway portion 3b which is in rolling contact with the outer ring raceway surface 1a and the shaft outer peripheral surface 2a between both side surfaces 3a.
[0009]
Specifically, as shown in FIG. 2A, the cylindrical roller 3 is formed at both ends in the width direction (left-right direction in the figure) with a predetermined chamfered R dimension, and the effective track portion 3b and each side surface 3a. A chamfered portion 3c is provided continuously.
The effective track portion 3b is provided with a flat portion 3b1 formed in a straight section and a crowning portion 3b2 provided at both ends of the effective track portion 3b for suppressing edge loading. The crowning portion 3b2 is formed by applying, for example, a cross-sectional arc-shaped crowning having a predetermined curvature to both ends of the effective track portion 3b, and is provided so as to be continuous with the flat portion 3b1 and the chamfered portion 3c. ing.
[0010]
Further, the surfaces of the flat portion 3b1 and the crowning portion 3b2 are superfinished to a desired roughness with a superfinishing grindstone set on the grinder by the cylindrical rollers 3 being fed through to the centerless grinder. ing. Specifically, the surface of the flat portion 3b1 is finished to have a ten-point average roughness Rz of about 0.4 μm or a center line average roughness Ra of about 0.08 μm. Further, the surface of the crowning portion 3b2 shown in FIG. 2 (b) has a roughness equal to or higher than that of the flat portion 3b1, that is, a ten-point average roughness Rz, by increasing the time of through-feeding to the grinding machine. The center line average roughness Ra is 0.4 μm or less or 0.08 μm or less. In addition, when a burr | flash etc. arise in the connection location etc. of the flat part 3b1 and the crowning part 3b2, it is preferable to perform a barrel process or a tumbler process after the said super finishing process, and to remove a burr | flash etc.
[0011]
Here, the durability test conducted by the inventor of the present invention will be described with reference to FIGS.
In this endurance test, the effects of changing the surface roughness of the flat portion 3b1 and the crowning portion 3b2 by preparing test products 1 to 4 of the present invention and comparative products 1 and 2 of the conventional equivalent are prepared. It was confirmed. The test products 1 and 2 have the 10-point average roughness Rz of the flat portion 3b1 and the crowning portion 3b2 shown in FIG. 2A of 0.4 μm and 0.2 μm, respectively, or the center line average roughness Ra of 0.08 μm, respectively. The specimens 3 and 4 have a 10-point average roughness Rz of 0.4 μm and 0.4 μm or a center line average roughness Ra of 0 and 0, respectively, for the flat portion 3b1 and the crowning portion 3b2. 0.08 μm and 0.08 μm. In addition, as shown in FIGS. 4A and 4B, the comparative products 1 and 2 have chamfered portions 4c that are continuous with the side surfaces 4a of the cylindrical rollers 4 and that are the same as the chamfered portions 3c. Further, between the chamfered portion 4c, a flat portion 4b1 and a crowning having a ten-point average roughness Rz of 0.4 μm and 0.6 μm, respectively, or a center line average roughness Ra of 0.08 μm and 0.12 μm, respectively. An effective track portion 4b composed of the portion 4b2 is provided.
[0012]
Further, in this durability test, the cylindrical roller is attached to the shaft 2 in a state where the axial center of the outer ring 1 is inclined by 10 minutes with respect to the axial center of the shaft 2 so that surface damage is likely to occur on the cylindrical rollers 3 and 4 and the shaft 2. 3 and 4 and the outer ring 1 were assembled, and the shaft 2 was continuously rotated at 4000 rpm with a radial load of 14100 N (1438 kgf) applied to the outer ring 1. Then, as shown in Table 1, the operation time until surface damage occurred in these components was confirmed, and the B 10 life time until 10% of the product was damaged was obtained as the cumulative failure probability. In Table 1, the number of tests is two sets of each pair of sudden death tests.
[0013]
[Table 1]
Figure 0004075364
[0014]
As shown in Table 1, the B 10 life time, the specimens 1 and 2 longest, followed by a sequence of test article 3, 4 and comparative products 1 and 2.
Further, as shown in FIGS. 3A and 3B, for example, in the test products 1 and 2, the surface of the cylindrical roller 3 is hardly damaged, and the internal origin peeling is slightly caused on the outer peripheral surface 2 a of the shaft 2. It was happening. This internal origin peeling is considered to be caused by the outer ring 1 and the cylindrical roller 3 being assembled with the shaft 2 tilted with respect to the shaft 2, and the actual product does not cause an early failure due to rolling fatigue.
On the other hand, in comparison products 1 and 2, a lubrication failure such as oil film breakage occurred in a short time compared to the above-described test products 1 and 2, and as shown in FIG. The surface layer peeling occurred on the test products 1 and 2. Further, as shown in FIG. 4C, countless scratches were also generated on the surfaces of the crowning portion 4b2 and further the flat portion 4b1.
[0015]
As described above, in the cylindrical roller bearing of the present embodiment, the surface roughness of the crowning portion 3b2 in the effective raceway portion 3b including the flat portion 3b1 and the crowning portion 3b2 continuous at both ends thereof is set to a value other than the crowning portion 3b2. It was confirmed that surface damage such as surface peeling can be prevented from occurring in the roller and the part to be supported by finishing the effective track portion 3b (ie, the flat portion 3b1) with a surface roughness equal to or greater than the surface roughness. Further, as is clear from the test results of the test products 3 and 4 and the comparative products 1 and 2, the ten-point average roughness Rz of the crowning portion 3b2 is 0.4 μm or less or the center line average roughness Ra is 0.08 μm. It was confirmed that the surface damage can be more effectively suppressed by the following.
[0016]
In the above description, the case where the present invention is applied to a shaft direct type cylindrical roller bearing has been described. As long as it is equivalent to or better than that, there is no limitation . Also, cylindrical rollers may be applied to the inner ring raceway surface and the cylindrical roller bearing constructed in accordance with the supported target part of the surface of at least one of the raceway surface of the outer ring raceway surface for rolling. For example, in the roller mill, the inner peripheral surface of the roll as the outer ring raceway surface, the cylindrical rollers can be directly applied to the cylindrical roller bearing for rolling.
[0017]
In the above description, the case where the crowning portion 3b2 is formed at both ends of the effective raceway portion 3b of the cylindrical roller 3 has been described. .
In the above description, the crowning portion 3b2 having a cross-sectional arc-shaped crowning having a predetermined curvature has been described. However, the shape of the crowning is not limited to the above-described arc-shaped cross-section.
[0018]
【The invention's effect】
The present invention configured as described above has the following effects.
Cylindrical roller bearing according to claim 1, it is possible to prevent the surface damage such as surface flaking occurs rollers and support target part cylinder, to improve the durability of the cylindrical roller and the support target part, said bearing and support The life of the target part can be extended.
[0019]
According to the cylindrical roller bearing of claim 2, since the surface damage can be more effectively suppressed, the durability of the cylindrical roller and the support target component is further improved, and the life of the bearing and the support target component is further increased. Can be extended.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cylindrical roller bearing according to an embodiment of the present invention.
2A is an enlarged view showing a configuration of a main part of the cylindrical roller shown in FIG. 1, and FIG. 2B is an enlarged view of a portion surrounded by line IIb in FIG.
3 is a diagram showing the results of a durability test of the cylindrical roller bearing shown in FIG. 1, (a) is a diagram showing the state of the cylindrical roller surface after the durability test, and (d) is a diagram after the durability test. It is a figure which shows the state of a shaft surface.
4A and 4B are diagrams showing test results of comparative products in the durability test, wherein FIG. 4A is a diagram showing a state of a cylindrical roller surface of a comparative product before the durability test, and FIG. 4B is a diagram showing IVb of FIG. It is an enlarged view of the part enclosed with the line, (c) is a figure which shows the state of the cylindrical roller surface after an endurance test, (d) is a figure which shows the state of the shaft surface after an endurance test.
[Explanation of symbols]
1 Outer ring 1a Outer ring raceway surface 2 Shaft (supported part as inner ring)
2a Outer peripheral surface (inner ring raceway surface)
3 Cylindrical roller 3b Effective track part 3b2 Crowning part

Claims (2)

軸受用鋼からなる複数の円筒ころと、これらの円筒ころが転動する内輪軌道面及び外輪軌道面の少なくとも一方の軌道面を支持対象部品の表面により構成した円筒ころ軸受であって、
前記複数の各円筒ころの有効軌道部の端部に、クラウニングを施したクラウニング部を形成し、
前記支持対象部品の軸中心に対して、前記内輪軌道面及び前記外輪軌道面の他方の軌道面の軸中心が傾いた状態で発生する油膜切れに起因する前記円筒ころ又は前記支持対象部品の表面損傷を抑制するべく、超仕上砥石によって、前記クラウニング部の表面の粗さを、当該クラウニング部を除く断面直線状の前記有効軌道部の表面の粗さと同等以上にしたことを特徴とする円筒ころ軸受。A plurality of cylindrical rollers made of bearing steel, a inner ring raceway surface and the cylindrical roller bearing constructed in accordance with the surface of the supporting object component at least one of the raceway surface of the outer ring raceway surface in which these cylindrical rollers roll,
At the end of the effective track portion of each of the plurality of cylindrical rollers, a crowning portion that is crowned is formed ,
The surface of the cylindrical roller or the part to be supported due to the oil film breakage occurring when the axis center of the other raceway surface of the inner ring raceway surface and the outer ring raceway surface is inclined with respect to the axis center of the part to be supported. In order to suppress damage, a cylindrical roller characterized in that the roughness of the surface of the crowning portion is equal to or greater than the roughness of the surface of the effective track portion having a linear cross section excluding the crowning portion by a superfinishing grindstone. bearing. 前記クラウニング部の表面の十点平均粗さを０．４μｍ以下としたことを特徴とする請求項１記載の円筒ころ軸受。The cylindrical roller bearing according to claim 1, wherein a ten-point average roughness of the surface of the crowning portion is 0.4 μm or less.
JP2001374494A 2001-12-07 2001-12-07 Cylindrical roller bearing Expired - Fee Related JP4075364B2 (en)

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WO2024161875A1 (en) * 2023-01-30 2024-08-08 Ntn株式会社 Rolling bearing

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JP2005106234A (en) * 2003-10-01 2005-04-21 Ntn Corp Conical roller bearing and method for working conical roller bearing
JP2007155021A (en) * 2005-12-06 2007-06-21 Nsk Ltd Roller bearing
JP6517105B2 (en) * 2015-07-21 2019-05-22 Ntn株式会社 Superfinishing method of roller bearing rolling surface

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Publication number Priority date Publication date Assignee Title
WO2024161875A1 (en) * 2023-01-30 2024-08-08 Ntn株式会社 Rolling bearing

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