JP3047088B2 - Machine parts having rolling elements - Google Patents
Machine parts having rolling elementsInfo
- Publication number
- JP3047088B2 JP3047088B2 JP4078888A JP7888892A JP3047088B2 JP 3047088 B2 JP3047088 B2 JP 3047088B2 JP 4078888 A JP4078888 A JP 4078888A JP 7888892 A JP7888892 A JP 7888892A JP 3047088 B2 JP3047088 B2 JP 3047088B2
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- steel
- gas
- hardened
- quenching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- 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
- F16C33/32—Balls
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- 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
- F16C33/62—Selection of substances
-
- 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
- F16C2204/00—Metallic materials; Alloys
- F16C2204/60—Ferrous alloys, e.g. steel alloys
- F16C2204/64—Medium carbon steel, i.e. carbon content from 0.4 to 0,8 wt%
-
- 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
- F16C2204/00—Metallic materials; Alloys
- F16C2204/60—Ferrous alloys, e.g. steel alloys
- F16C2204/66—High carbon steel, i.e. carbon content above 0.8 wt%, e.g. through-hardenable steel
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Rolling Contact Bearings (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Sliding-Contact Bearings (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、構成部材の材質及び熱
処理によって、寿命を改善した等速自在継手及び転がり
軸受などの機械部品に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to mechanical parts such as constant velocity universal joints and rolling bearings whose life has been improved by the material and heat treatment of constituent members.
【0002】[0002]
【従来の技術】等速自在継手の外輪や、また転がり軸受
の中でハブベアリングの軌道輪は、複雑な形状を有して
いるので、鍛造容易な中炭素含有鋼により熱間鍛造で形
成され、その転走面や摺動面は高周波焼入れ・焼戻しさ
れて形成されている。また転動体は単純形状であって、
焼入れ性よく転動寿命にすぐれた軸受鋼、特に高炭素ク
ロム軸受鋼などにより、一体焼入れ(ずぶ焼入れ)焼戻
しされて使用される。2. Description of the Related Art Outer races of constant velocity universal joints and raceways of hub bearings among rolling bearings have a complicated shape, and are formed by hot forging with a medium carbon-containing steel which is easily forged. The rolling and sliding surfaces are formed by induction hardening and tempering. The rolling element has a simple shape,
Bearing steel with good quenching properties and excellent rolling life, especially high carbon chromium bearing steel, is used after being integrally quenched (submerged quenching).
【0003】高周波焼入れ材としては、鍛造容易な構造
用炭素鋼の他に、SiとAlとを総量で0.5〜1.0
%含有させた0.6〜0.8%Cの構造用鋼が開発され
て利用され(特開平3−199340号、特開平1−1
27651号)、これらの鋼種は、材料が安価で、か
つ、鍛造が容易であるから複雑な形状の外輪の成形に適
し、また、局部的な高周波焼入れであるから熱処理中の
変形少なく、且つ内質部は靱性があり、更に高周波焼入
れ焼戻し後の硬化層が耐熱性と耐磨耗性に優れているの
で、転がり疲労寿命の長い特長を有し、外輪及び内輪に
賞用されて来た。As the induction hardening material, in addition to the structural carbon steel which is easily forged, Si and Al are added in a total amount of 0.5 to 1.0.
% Of 0.6-0.8% C structural steel has been developed and used (JP-A-3-199340, JP-A-1-1340).
No. 27651), these steel grades are inexpensive and easy to forge, so they are suitable for forming an outer ring having a complicated shape. Also, since local induction hardening is used, deformation during heat treatment is small, and The quality part has toughness, and furthermore, the hardened layer after induction hardening and tempering has excellent heat resistance and abrasion resistance. Therefore, it has a feature of long rolling fatigue life and has been awarded as the outer ring and the inner ring.
【0004】また、上記の高炭素クロム軸受鋼により形
成して、その表面に浸炭窒化処理を行い、一体焼入れ後
に焼戻しをした転がり部品が提案されており(アメリカ
特許USP3216869)、また焼入れ後の比較的高
温焼戻しにより、内質部の残留オーステナイト量を極力
低減させ、表層の浸炭層は適量のオーステナイトを残留
させて転動疲労を向上させた熱処理法が知られている
(特開昭62−218542号)。[0004] Further, there has been proposed a rolling component formed of the above-mentioned high carbon chromium bearing steel, subjected to carbonitriding treatment on its surface, and tempered after integral quenching (US Pat. No. 3,216,869). A heat treatment method has been known in which the amount of retained austenite in the internal part is reduced as much as possible by a high-temperature tempering, and a suitable amount of austenite remains in the surface carburized layer to improve rolling fatigue (Japanese Patent Laid-Open No. 62-218542). issue).
【0005】[0005]
【発明が解決しようとする課題】一般に、高周波焼入れ
材を軸受の軌道輪や等速自在継手の外包部材に使用した
場合は、これら外包部材の寿命は、高炭素クロム軸受鋼
一体焼入れのボール転動体の寿命より短かった。しかる
に、上述のような寿命の長い高周波焼入れ材の外包部材
外輪が出現するに伴い、また、自動車用の軸受や等速自
在継手に小型化・軽量化が要求されるに伴い、転走面等
の高面圧下での使用条件で、相対的に軸受鋼による一体
焼入れ転動体の疲労寿命に不満を生じることとなった。In general, when an induction hardened material is used for a bearing race of a bearing or an outer casing member of a constant velocity universal joint, the life of these outer casing members is increased by the ball rolling of a high carbon chromium bearing steel integral hardening. It was shorter than the life of the moving object. However, as the outer ring of the outer casing member of the induction hardened material having a long service life as described above has appeared, and as the size and weight of automobile bearings and constant velocity universal joints have been required to be reduced, rolling surfaces and the like have been required. Under the conditions of use under high surface pressure, the fatigue life of the integrally quenched rolling element made of the bearing steel was relatively dissatisfied.
【0006】高面圧下での使用条件では、転動体の疲労
寿命は、高周波焼入れ材の焼入れ硬化した転走面又は摺
動面の磨耗によって発生する磨耗粉によって、転動体の
表面が剥離して生じるのである。転動体の剥離は、特
に、等速自在継手のように、転動体と外輪等の摺動面に
転がり運動とともにすべり運動が関与する場合に大き
い。[0006] Under the conditions of use under high surface pressure, the fatigue life of the rolling element is determined by the fact that the surface of the rolling element is peeled off by wear powder generated by wear of the quenched and hardened rolling surface or sliding surface of the induction hardened material. It will happen. Peeling of the rolling element is particularly large when a sliding motion is involved together with the rolling motion on the sliding surface of the rolling element and the outer ring, such as a constant velocity universal joint.
【0007】また、外包部材に上記の高炭素鋼の浸炭窒
化処理品を使用するのは、複雑な形状に鍛造するのが困
難であって、切削加工に頼らざるを得ず、量産性に欠
け、製造コストが高価となり、実用的ではなかった。Further, the use of the above carbonitrided high carbon steel product for the outer casing member is difficult because it is difficult to forge into a complicated shape, so that it has to rely on cutting work, and lacks mass productivity. However, the manufacturing cost is high and it is not practical.
【0008】本発明は以上の問題を解決すべく、内輪、
特に外輪の長寿命化に対応した転動体の剥離による寿命
限界を改善して、寿命が長く信頼性が高い、且つ量産性
に優れた軸伝動部材や軸受などの機械部品を提供しよう
とするものである。[0008] The present invention solves the above problems by providing an inner ring,
In particular, it is intended to provide a mechanical component such as a shaft transmission member or bearing that has a long life, is highly reliable, and is excellent in mass productivity by improving the life limit due to the separation of rolling elements corresponding to a longer life of the outer ring. It is.
【0009】[0009]
【課題を解決するための手段】本発明の機械部品は、内
面に転走面若しくは摺動面を具備した外包部材と、外面
に転走面若しくは摺動面を具備した内包部材と、当該外
包部材と内包部材との転走面若しくは摺動面の間に介装
された転動体と、から成るものであるが、当該外包部材
の当該転走面若しくは摺動面に高周波焼入れによる硬化
層を有する構造用中炭素高周波焼入れ用鋼により形成さ
れ、当該転動体は、その外周表面に浸炭窒化された表層
部を有して、且つ焼入れ焼戻しされた高炭素クロム軸受
鋼によって形成されたことを特徴とするものである。こ
のような機械部品には、等速自在継手や転がり軸受があ
る。According to the present invention, there is provided a mechanical part comprising an outer member having a rolling surface or a sliding surface on an inner surface, an inner member having a rolling surface or a sliding surface on an outer surface, and the outer member. A rolling element interposed between the rolling surface or the sliding surface of the member and the inner member, and a hardened layer formed by induction hardening on the rolling surface or the sliding surface of the outer member. The rolling element is formed of high-carbon chromium bearing steel having a carbonitrided surface layer on the outer peripheral surface thereof and having been hardened and tempered. It is assumed that. Such mechanical parts include constant velocity universal joints and rolling bearings.
【0010】また、本発明は、当該転動体の表層部が、
窒素ガス若しくはNXガスと炭化水素ガスとアンモニア
ガスとの混合ガス中の浸炭窒化による硬化表層部である
上記の機械部品が包含される。更に、上記外包部材の構
造用中炭素高周波焼入れ用鋼は、Cを0.45〜0.8
5%含有する炭素鋼、例えば、S53C鋼の他に、少な
くとも、Cを0.50〜0.70%と、Siを単独で若
しくはAlを単独で、又はSi及びAlの総量を0.5
〜1.0%とを含有して成る鋼が含まれる。更に、Mn
とCrをそれぞれ1.5%以下含有されていても良い。Further, according to the present invention, the surface portion of the rolling element is preferably
The above mechanical parts which are hardened by carbonitriding in a mixed gas of nitrogen gas or NX gas, hydrocarbon gas and ammonia gas are included. Further, the structural medium carbon induction hardening steel of the outer casing member has a C of 0.45 to 0.8.
In addition to carbon steel containing 5%, for example, S53C steel, at least 0.50 to 0.70% of C, Si alone or Al alone, or a total amount of Si and Al of 0.5%
鋼 1.0%. Further, Mn
And Cr each in an amount of 1.5% or less.
【0011】[0011]
【作用】外包部材は、中炭素の高周波焼入れ鋼で形成さ
れ、その転動・摺動面が高周波焼入れ後の焼戻しをされ
ているから、未焼入れの内質部が耐衝撃特性の良いほぼ
軟質とされているの対して、転動面等の焼入れ硬化した
表層部には高周波焼入れの際の変態に伴う圧縮応力が残
留しているから、表層部における亀裂の大きな剥離への
進展が遅く、疲労寿命が長い。[Function] The outer casing member is made of medium-carbon induction hardened steel and its rolling and sliding surfaces are tempered after induction hardening, so that the unhardened inner part is almost soft with good impact resistance. On the other hand, the compressive stress accompanying the transformation during induction hardening remains in the quenched and hardened surface layer such as the rolling surface, so the progression to large peeling of cracks in the surface layer is slow, Long fatigue life.
【0012】特に、当該中炭素高周波焼入れ用鋼がSi
を単独で、若しくはAlを単独で又はSiとAlとを総
和で0.5〜1.0%、Cを0.50〜0.70%含有
する鋼であるときは、AlとSiの耐焼戻し抵抗を利用
して、焼戻し硬度を低下させずに、焼戻し温度を高くし
て残留オーステナイトを15%以下の適量に調整して、
耐磨耗性と共に転がり疲労寿命が向上する。In particular, the medium-carbon induction hardening steel is made of Si.
Steel alone, or Al alone or a steel containing 0.5 to 1.0% in total of Si and Al and 0.50 to 0.70% of C, tempering resistance of Al and Si Utilizing the resistance, without lowering the tempering hardness, the tempering temperature is raised and the residual austenite is adjusted to an appropriate amount of 15% or less,
Rolling fatigue life is improved with abrasion resistance.
【0013】他方、転動体の高炭素クロム軸受鋼は、浸
炭窒化焼入れすると、転動体表層部の炭素・窒素濃化層
のMs点が低下して、オーステナイト化後の焼入れ過程
で、浸炭窒化表層部のマルテンサイト変態が内部よりも
遅れるので、変態後の表層部に圧縮応力が発生し、残留
オーステナイト量が増加し、且つ表層部のマトリックス
の硬度が上昇して、耐磨耗性と疲労強度が向上する。On the other hand, when carbonitriding and quenching and quenching and quenching and quenching and quenching and quenching the high carbon chromium bearing steel of the rolling element, the Ms point of the carbon / nitrogen-enriched layer of the rolling element surface decreases, and during the quenching process after austenitization, the carbonitrided Since the martensitic transformation of the part is slower than the inside, compressive stress is generated in the surface part after transformation, the amount of retained austenite increases, and the hardness of the matrix in the surface part increases, resulting in wear resistance and fatigue strength. Is improved.
【0014】浸炭窒化焼入れされた転動体が、外輪又は
内輪の転走面の磨耗により発生する磨耗粉のかみ込みに
対して、転動体表面の剥離が遅延して、寿命が長くなる
ので、転がり軸受全体として、あるいは自在継手全体と
しての寿命が長くなり、長寿命に伴う信頼性が向上す
る。The carbonized and quenched and quenched rolling element delays the exfoliation of the rolling element surface due to the ingress of abrasion powder generated by abrasion of the rolling surface of the outer ring or the inner ring, resulting in a longer life. The life of the bearing as a whole or the universal joint as a whole is lengthened, and the reliability associated with the long life is improved.
【0015】当該転動体の表層部は、窒素ガス若しくは
NXガスと炭化水素ガスとアンモニアガスとの混合ガス
中の浸炭窒化による場合、浸窒量が大きく、焼入れによ
る硬化が大きいので、耐磨耗性と疲労強度が向上する。
又、従来の浸炭用RXガスに窒化剤アンモニアガスを混
合した雰囲気には水素ガスを多量に含有するが、NXガ
スを基礎とするから、転動体の使用過程での水素脆性の
懸念が少なくなる。When the surface layer of the rolling element is formed by carbonitriding in a mixed gas of nitrogen gas or NX gas, hydrocarbon gas and ammonia gas, the amount of nitriding is large, and the hardening due to quenching is large, so that the abrasion resistance is high. Strength and fatigue strength are improved.
Also, the atmosphere in which the nitriding agent ammonia gas is mixed with the conventional carburizing RX gas contains a large amount of hydrogen gas, but since it is based on NX gas, there is less concern about hydrogen embrittlement in the process of using the rolling elements. .
【0016】[0016]
【実施例】本発明の実施例を、まず、図面に基づき、説
明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described first with reference to the drawings.
【0017】図1(A)は、一例として、自動車に使用
される車軸用軸受の断面図を示しているが、外包部材で
ある軸受外輪7には、外側に一体にフランジ5が取着さ
れており、フランジ5には、フランジ固定用ボルトが挿
通固定されるボルト孔51が設けられている。外輪7の
内面には、転動体であるボール8,8が転走する転走面
6、6を有する転走溝が2列周設されている。FIG. 1A is a cross-sectional view of an axle bearing used in an automobile as an example. A flange 5 is integrally attached to the outer periphery of a bearing outer ring 7 which is an outer member. The flange 5 is provided with a bolt hole 51 through which a flange fixing bolt is inserted and fixed. On the inner surface of the outer ring 7, two rows of rolling grooves having rolling surfaces 6, 6 on which balls 8, 8 as rolling elements roll, are provided.
【0018】内包部材である内輪2は、それぞれ一端に
拡径部21に上記ボール8が転走する転走面1を有する
一対の内輪2a,2bから成り、その他端面が互いに突
接されて、且つ、転走面1,1がボール8,8に摺接し
て、外輪7の中空部内に装入されて、外輪7内に回転自
在に保持されている。The inner ring 2, which is an inner member, comprises a pair of inner rings 2a and 2b having a rolling surface 1 on one end of which the ball 8 rolls on an enlarged diameter portion 21. The other end surfaces are in abutting contact with each other. In addition, the rolling surfaces 1, 1 are in sliding contact with the balls 8, 8, are inserted into the hollow portion of the outer ring 7, and are rotatably held in the outer ring 7.
【0019】外輪7は、構造用炭素鋼S53CやAl又
はSiを添加した0.50〜0.70%C鋼により、熱
間鍛造により一体に成形され、内周面の転走面6,6と
その周辺部にのみ、高周波焼入れとその後の焼戻しによ
る硬化層61が形成されている。また、内輪2は、比較
的円筒状に近い形状であるから、高炭素クロム軸受鋼S
UJ2鋼から形成され、一体焼入れ(ずぶ焼入れ)後の
焼戻しがされている。ボール8は、SUJ2鋼で形成さ
れ、ガス浸炭窒化処理して後一体焼入れ(ずぶ焼入れ)
・焼戻しが施されている。The outer race 7 is integrally formed by hot forging from structural carbon steel S53C or 0.50 to 0.70% C steel to which Al or Si is added, and the rolling surfaces 6 and 6 on the inner peripheral surface are formed. A hardened layer 61 formed by induction hardening and subsequent tempering is formed only in and its peripheral portion. Further, since the inner ring 2 has a relatively cylindrical shape, the high carbon chromium bearing steel S
It is formed from UJ2 steel and tempered after integral quenching (soothe quenching). The ball 8 is formed of SUJ2 steel, is subjected to gas carbonitriding, and is then integrally quenched.
・ Tempered.
【0020】図1(B)は、固定型ボールジョイントの
実施例で、外包部材である外輪7はマウス部7aの内周
面に転走面6を有する数条の転走溝が軸方向に沿って半
径方向に湾曲するように刻設され、マウス部7aの端部
に一体に突設された軸のステム部7bには外周にセレー
ション71が転造されている。外輪7は、構造用炭素鋼
S53CやAl又はSiを添加した0.50〜0.70
%C鋼により、熱間鍛造により一体に成形され、マウス
部7aの内周面は、転走面6を含めて、高周波焼入れと
その後の焼戻しによる硬化層61が形成されている。FIG. 1B shows an embodiment of a fixed type ball joint. An outer ring 7 as an outer wrapping member has several rolling grooves having a rolling surface 6 on an inner peripheral surface of a mouth portion 7a in an axial direction. A serration 71 is formed on the outer periphery of a stem 7b of a shaft which is engraved so as to be curved in the radial direction along the end of the mouth 7a. The outer ring 7 is made of structural carbon steel S53C or 0.50 to 0.70 to which Al or Si is added.
The mouth portion 7a is integrally formed with a hardened layer 61 by induction hardening and subsequent tempering, including the rolling surface 6, on the inner peripheral surface of the mouth portion 7a.
【0021】外輪7のマウス部7a内に、外周に転走溝
に嵌まる転動体のボール8を介して保持された内包部材
の内輪2は、浸炭焼入れ後の焼戻しがされたSCr41
5鋼から形成されて、少なくとも転走溝内の転走面1が
硬化されている。当該ボール8は、ガス浸炭窒化処理し
て後焼入れ焼戻しが施されたSUJ2鋼で形成されてい
る。The inner ring 2 of the inner member, which is held in the mouth portion 7a of the outer ring 7 via the ball 8 of the rolling element which fits into the rolling groove on the outer periphery, is made of the tempered SCr41 after carburizing and quenching.
5 and at least the rolling surface 1 in the rolling groove is hardened. The ball 8 is made of SUJ2 steel that has been subjected to gas carbonitriding and post-quenching and tempering.
【0022】次に、このような外包部材を形成する高周
波焼入れ用鋼の寿命試験を示す。高周波焼入れ用鋼とし
ては、炭素鋼S53Cと、Si添加炭素鋼(NKJ6
5、組成0.65%C、0.80%Si、1.10%M
n、0.015%P、0.010%S、0.030%A
l、0.20%Cr)であって精密研摩代を残して、円
筒状に施削加工し、常用の外周面の高周波焼入れと焼戻
しを行い、直径12mm、長さ22mmの円筒試片に仕
上げた。Next, a life test of the steel for induction hardening forming such an outer casing member will be described. As the steel for induction hardening, carbon steel S53C and Si-added carbon steel (NKJ6
5. Composition 0.65% C, 0.80% Si, 1.10% M
n, 0.015% P, 0.010% S, 0.030% A
l, 0.20% Cr), leaving a precise polishing allowance, and machined into a cylindrical shape, and induction hardening and tempering of the usual outer peripheral surface to finish into a cylindrical specimen 12 mm in diameter and 22 mm in length Was.
【0023】比較例として、高炭素クロム軸受鋼SUJ
2鋼を一体焼入れ、焼戻しして、同様の円筒試片に仕上
げた。As a comparative example, a high carbon chromium bearing steel SUJ
The two steels were integrally quenched and tempered to obtain a similar cylindrical specimen.
【0024】次に、この円筒試片を用いて、円筒型転動
疲労寿命試験機(エヌティエヌ(株)製)を用いて、ヘ
ルツ最大接触応力600kgf/mm2 の荷重下で回転
速度23120rpmにより寿命試験を行った。その結
果を表1に示す。Next, using the cylindrical specimen, a cylindrical rolling contact fatigue life tester (manufactured by NTN Corporation) was used at a rotational speed of 23,120 rpm under a load of Hertz maximum contact stress of 600 kgf / mm 2. The test was performed. Table 1 shows the results.
【0025】[0025]
【表1】 [Table 1]
【0026】表1の結果より、NKJ65の高周波焼入
れ品がSUJ2の一体焼入れ品よりすぐれた寿命を表し
ているのが判る。From the results shown in Table 1, it can be seen that the induction hardened product of NKJ65 has a better life than the integrally hardened product of SUJ2.
【0027】次に、上述の車軸用軸受を想定して、外輪
に中炭素鋼(S53Cと上記組成のNKJ65)の高周
波焼入れ品を、内輪に高炭素クロム軸受鋼SUJ2鋼の
焼入れ焼戻し品を、また転動体として高炭素クロム軸受
鋼のボールの浸炭窒化焼入れ品を使用して、軸受の転が
り寿命試験を行った。Next, assuming the above-described axle bearing, an induction hardened product of medium carbon steel (S53C and NKJ65 of the above composition) is used for the outer ring, and a quenched and tempered product of high carbon chromium bearing steel SUJ2 steel is used for the inner ring. A rolling life test of the bearing was performed using a carbonitrided and quenched product of a high carbon chromium bearing steel ball as a rolling element.
【0028】ボールの浸炭窒化は、光輝焼入れ炉によ
り、光輝焼入れ用のRXガスを容積比で100部に対し
て、プロパンガス1部とアンモニアガス10部を加えた
雰囲気中で850℃×1.5h加熱した後、油中焼入れ
をした。焼戻しは170℃×2hで行った。The carbonitriding of the balls is carried out by a bright quenching furnace in an atmosphere in which 1 part of propane gas and 10 parts of ammonia gas are added to 100 parts by volume of a bright quenching RX gas and 100 parts by volume of ammonia gas. After heating for 5 h, it was quenched in oil. Tempering was performed at 170 ° C. × 2 hours.
【0029】比較例として、外輪に高炭素クロム鋼SU
J2の焼入れ及びボールに同じくSUJ2鋼の焼入れを
したものの寿命試練を行った。その結果を表2に示し
た。As a comparative example, a high carbon chromium steel SU was used for the outer ring.
The life test was performed on the quenched J2 and the quenched SUJ2 steel in the ball. The results are shown in Table 2.
【0030】寿命試験条件は、試験軸受6206、軸受
荷重700kgf、回転数2000rpm、潤滑はター
ビン56油の循環給油であった。The life test conditions were as follows: test bearing 6206, bearing load 700 kgf, rotation speed 2000 rpm, lubrication was circulation oil supply of turbine 56 oil.
【0031】[0031]
【表2】 [Table 2]
【0032】表2から、寿命試験により破損した軸受に
おいて、ボール自体に表面剥離を有する頻度は、中炭素
鋼の外輪と、高炭素クロム鋼の一体焼入れのボールとの
従来の組み合わせよりも、高炭素クロム鋼の浸炭窒化焼
入れのボールとの組み合わせの方が小さくなっており、
外輪・ボールとも一体焼入れをした場合と同程度であっ
て、しかも寿命は延びていることが判る。From Table 2, it can be seen that the frequency of surface peeling of the ball itself in bearings damaged by the life test is higher than that of the conventional combination of a medium carbon steel outer ring and a high carbon chromium steel integrally hardened ball. The combination with carbon nitrocarburized and quenched balls of carbon chrome steel is smaller,
It can be seen that the outer ring and the ball are almost the same as those obtained by quenching together, and the life is extended.
【0033】外輪を中炭素鋼の高周波焼入れ品とし、転
動体のボールを高炭素クロム鋼SUJ2の浸炭窒化焼入
れ品とした等速自在継手の実施例を次に示す。An embodiment of a constant velocity universal joint in which the outer race is made of induction hardened medium carbon steel and the rolling element ball is made of carbonitrided and quenched high carbon chromium steel SUJ2 will be described below.
【0034】転動体は、直径16.669mmの鋼球
で、光輝焼入れ炉を利用して、搬送ガスとしてRXガス
とNXガスを選び、常温1気圧下容積比で、この搬送ガ
スに100部に対して浸炭剤としてのブタンガス1部と
窒化剤としてアンモニアガス10部を混合した雰囲気中
で850℃×2hの浸炭窒化処理を行い油冷後、170
℃×2hで焼戻しを行った。The rolling element is a steel ball having a diameter of 16.669 mm. A bright quenching furnace is used to select RX gas and NX gas as carrier gases. On the other hand, in an atmosphere in which 1 part of butane gas as a carburizing agent and 10 parts of ammonia gas as a nitriding agent are mixed, a carbonitriding treatment at 850 ° C. × 2 hours is performed, and after oil cooling, 170
Tempering was performed at 2 ° C. × 2 hours.
【0035】図2は、浸炭窒化焼入れ後焼戻しの処理を
した鋼球断面における表面から内質部に亘ってマイクロ
ヴィカース硬度試験機により測定した硬度分布曲線を示
している。浸炭窒化処理を行えば、表層が内質部より若
干硬化するが、NXガスを基礎とした雰囲気の処理の方
(図中a曲線)が、RXガスのものより(図中b曲
線)、表層部の硬度が高く、ロックウェルC硬度に換算
してHRC1〜2程度上昇する。FIG. 2 shows a hardness distribution curve measured from a surface to an inner part of a steel ball cross-section subjected to a carbonitriding quenching and quenching followed by a tempering treatment using a micro Vickers hardness tester. When the carbonitriding treatment is performed, the surface layer is slightly hardened from the inner part, but the treatment in the atmosphere based on the NX gas (curve a in the figure) is better than that in the RX gas (curve b in the figure). The hardness of the portion is high, and it increases by about HRC 1 to 2 in terms of Rockwell C hardness.
【0036】図3は、当該熱処理の鋼球の断面の表面近
傍の顕微鏡写真であるが、NXガスを基礎とした雰囲気
で浸炭窒化した鋼球の表層に微細な炭化物が認められる
(同図(A))。この微細な炭化物が耐磨耗性の向上に
寄与していると考えられる。FIG. 3 is a micrograph of the vicinity of the surface of the cross section of the steel ball in the heat treatment. Fine carbides are recognized on the surface layer of the carbon ball nitrided in an atmosphere based on NX gas (FIG. A)). It is considered that this fine carbide contributes to the improvement of wear resistance.
【0037】図4は、図2に示したような低温焼戻しの
後、さらに500℃1hの高温焼戻しを行った鋼球の硬
度分布を示している。この高温焼戻しによって、内質部
はHv500以下に軟化するが、表層部は、なおHv6
00以上の硬度を有しており、このことは使用中の摩擦
による転走面の発熱があっても軟化し難いことを示しし
ているが、この表層の硬さは表面より浸透した窒素によ
り硬化しているものである。さらに、図4において、N
Xガスを基礎にして浸炭窒化処理した鋼球の表面の硬化
層の硬さ(図中a曲線)がRXガスを基礎にして浸炭窒
化処理した鋼球の硬さ(図中b曲線)より大きく、この
硬度差は表層部の窒素量の差に起因するものと考えられ
る。FIG. 4 shows the hardness distribution of steel balls which were subjected to high-temperature tempering at 500 ° C. for 1 hour after low-temperature tempering as shown in FIG. By this high-temperature tempering, the inner part is softened to Hv500 or less, but the surface layer is still Hv6.
It has a hardness of 00 or more, which indicates that it is difficult to soften even if the rolling surface generates heat due to friction during use, but the hardness of this surface layer is due to nitrogen permeating from the surface. It is hardened. Further, in FIG.
The hardness of the hardened layer on the surface of the steel ball carbonitrided on the basis of X gas (curve a in the figure) is greater than the hardness of the carbon ball carbonitrided on the basis of RX gas (curve b in the figure) This difference in hardness is considered to be caused by the difference in the amount of nitrogen in the surface layer.
【0038】次に、等速自在継手の寿命試験を行った。
継手は図1(B)に示したような固定型ボールジョイン
トであって、外輪は、S53C鋼及び上記NKJ65鋼
の鍛造品をマウス部内周面に高周波加熱焼入れしたもの
である。内輪は従来と同じく、SCr415鋼の浸炭焼
入れ品である。Next, a life test of the constant velocity universal joint was performed.
The joint is a fixed type ball joint as shown in FIG. 1 (B), and the outer ring is a forged product of S53C steel and the above-mentioned NKJ65 steel, which is induction hardened on the inner peripheral surface of the mouth part. The inner ring is a carburized and quenched product of SCr415 steel as before.
【0039】転動体としてのボールは、SUJ2鋼の浸
炭窒化焼入れ処理を行ったもので、浸炭窒化の際の炉内
雰囲気ガスは上述の実施例に示したように、搬送ガスに
RXガスを利用したものと、NXガスを使用したものと
があり、いずれもプロパンガスとアンモニアガスを混合
して形成したもので、熱処理条件は上記実施例と同じで
ある。また比較例は、従来のSUJ2鋼の一体焼入れ品
のボールを利用したボールジョイントである。The balls as the rolling elements are obtained by subjecting a SUJ2 steel to carbonitriding and quenching. The atmosphere gas in the furnace at the time of carbonitriding uses RX gas as a carrier gas as described in the above embodiment. There are two types, one using NX gas and one using NX gas. Both of them are formed by mixing propane gas and ammonia gas, and the heat treatment conditions are the same as in the above embodiment. The comparative example is a ball joint using a ball of a conventional SUJ2 steel integrally hardened product.
【0040】固定型ボールジョイントの寿命試験は、作
動角6°、負荷トルク21kgf−m、回転数1700
rpmの条件下で行った。The life test of the fixed type ball joint was performed at an operating angle of 6 °, a load torque of 21 kgfm, and a rotation speed of 1700.
This was performed under the condition of rpm.
【0041】試験結果を表3に示したが、同じく外輪に
高周波焼入れ品を使用した場合に、浸炭窒化焼入れされ
たボールが、従来の一体焼入れのボールに対して、継手
の寿命改善に有効である。また浸炭窒化焼入れ雰囲気が
RXガスを基礎とするものより、NXガスを基礎とする
浸炭窒化処理品が、転がり寿命に優れていることが判
る。The test results are shown in Table 3. When the induction hardened product is used for the outer ring, the carbonitrided and quenched ball is more effective in improving the life of the joint than the conventional integrally quenched ball. is there. In addition, it can be seen that the carbonitrided article based on the NX gas has a better rolling life than that based on the RX gas in the carbonitriding and quenching atmosphere.
【0042】[0042]
【表3】 [Table 3]
【0043】本実施例では、浸炭窒化性ガスとして、N
Xガスを基礎とする混合ガスを示したが、これに代え
て、窒素ガスに炭化水素ガスとアンモニアガスとを混合
したガスであってもよい。In this embodiment, N 2 is used as the carbonitriding gas.
Although the mixed gas based on the X gas is shown, a gas obtained by mixing a hydrocarbon gas and an ammonia gas with a nitrogen gas may be used instead.
【0044】[0044]
【発明の効果】本発明の転がり軸受及び等速継手を含む
機械部品は、外包部材が中炭素焼入れ用鋼で形成されて
成形性に富むので、複雑な形状の外包部材とすることが
できる。転走面・摺動面を含む内面を当該中炭素鋼の高
周波焼入れ硬化層とするので、転動体の転走・摺動に対
しての耐磨耗性において転動体よりやや劣るが耐剥離強
度においてすぐれている。他方、転動体は、高炭素クロ
ム鋼で形成され、その外周面には浸炭窒化焼入れによる
硬化表層を有しているから、一体焼入れ硬化体よりも耐
磨耗性と転動疲労にすぐれており、従って上記継手又は
軸受の全体として、疲労寿命が長くなる。According to the mechanical parts including the rolling bearing and the constant velocity joint of the present invention, since the outer casing member is formed of medium carbon hardening steel and has high formability, the outer casing member can have a complicated shape. Since the inner surface including the rolling surface and sliding surface is made of the induction hardened hardened layer of the medium carbon steel, the abrasion resistance of the rolling element against rolling and sliding is slightly inferior to that of the rolling element, but the peeling strength is low. Excellent in On the other hand, the rolling element is made of high carbon chromium steel and has a hardened surface layer by carbonitriding and quenching on its outer peripheral surface, so that it has better abrasion resistance and rolling fatigue than the integrally hardened and hardened body. Therefore, the fatigue life of the joint or the bearing as a whole is prolonged.
【0045】外包部材は、複雑形状であっても成形性及
び高周波加熱による熱処理を容易にすることができ、ま
た単純形状の転動体は、浸炭窒化処理に適しており、内
包部材に適当な材質を選択すれば、軸受又は継手の軽量
化が容易であり、成形・熱処理のコスト高を招くことな
く、量産化に適している。The outer casing member can be easily formed and heat-treated by high-frequency heating even if it has a complicated shape. The rolling element having a simple shape is suitable for carbonitriding treatment, By selecting, it is easy to reduce the weight of the bearing or the joint, and it is suitable for mass production without increasing the cost of molding and heat treatment.
【0046】また、転動体の浸炭窒化処理の雰囲気ガス
に、NXガス又は窒素ガスを搬送ガスとし、浸炭性の炭
化水素及び窒化性のアンモニアガスを混合することによ
って、転動体表面の耐磨耗性、転がり疲労寿命を改善す
ることができる。Further, the NX gas or the nitrogen gas is used as a carrier gas and the carburizing hydrocarbon and the nitriding ammonia gas are mixed with the atmosphere gas of the carbonitriding treatment of the rolling elements to thereby prevent wear of the surface of the rolling elements. Properties and rolling fatigue life can be improved.
【図1】自動車に使用される車軸用軸受(A)と固定型
ボールジョイント(B)の断面図。FIG. 1 is a cross-sectional view of an axle bearing (A) and a fixed ball joint (B) used in an automobile.
【図2】浸炭窒化焼入れした後焼戻しを行った鋼球の断
面における表層部のヴイッカース硬度分布を示す図。FIG. 2 is a view showing a Vickers hardness distribution of a surface portion in a cross section of a steel ball which has been tempered after carbonitriding and quenching.
【図3】浸炭窒化焼入れした後焼戻しを行った鋼球の断
面における金属組織の顕微鏡写真(A,B)(倍率;4
00、腐食液;ピクリン酸アルコール液)FIG. 3 is a micrograph (A, B) of a metal structure in a cross section of a steel ball which has been tempered after carbonitriding and quenching (magnification: 4).
00, corrosive liquid; picric acid alcohol liquid)
【図4】浸炭窒化焼入れ低温焼戻して、更に500℃1
hの高温焼戻しをした鋼球の断面における表層部のヴイ
ッカース硬度分布を示す図。FIG. 4 Carbonitriding and quenching and low-temperature tempering, followed by 500 ° C. 1
The figure which shows the Vickers hardness distribution of the surface layer part in the cross section of the steel ball which carried out the high temperature tempering of h.
1 内包部材の転走面 2 内包部材 4 保持器 5 フランジ 6 外装部材の転走面 61 高周波焼入れ硬化層 7 外装部材 8 ボール REFERENCE SIGNS LIST 1 Rolling surface of inner member 2 Inner member 4 Cage 5 Flange 6 Rolling surface of outer member 61 Induction hardened layer 7 Outer member 8 Ball
フロントページの続き (58)調査した分野(Int.Cl.7,DB名) F16C 33/32 F16C 33/62 C23C 8/32 F16D 3/20 904 Continuation of the front page (58) Field surveyed (Int. Cl. 7 , DB name) F16C 33/32 F16C 33/62 C23C 8/32 F16D 3/20 904
Claims (4)
外包部材と、外面に転走面若しくは摺動面を具備した内
包部材と、当該外包部材と内包部材との転走面若しくは
摺動面の間に介装された転動体と、から成る機械部品に
おいて当該外包部材は、当該転走面若しくは摺動面に高
周波焼入れによる硬化層を有する構造用中炭素高周波焼
入れ用鋼により形成され、 当該転動体は、その外周表面に浸炭窒化された表層部を
有して、且つ焼入れ焼戻しされた高炭素クロム軸受鋼に
よって形成されたことを特徴とする機械部品。1. An outer member having a rolling surface or a sliding surface on an inner surface, an inner member having a rolling surface or a sliding surface on an outer surface, and a rolling surface or a sliding surface between the outer member and the inner member. In a mechanical part comprising a rolling element interposed between the running surfaces, the outer casing member is formed of structural medium carbon induction hardened steel having a hardened layer formed by induction hardening on the rolling surface or the sliding surface. A mechanical component, wherein the rolling element has a carbonitrided surface layer on the outer peripheral surface thereof and is formed of quenched and tempered high carbon chromium bearing steel.
はNXガスと炭化水素ガスとアンモニアガスとの混合ガ
ス中の浸炭窒化による硬化表層部である請求項1記載の
機械部品。2. The mechanical part according to claim 1, wherein the surface layer of the rolling element is a surface layer hardened by carbonitriding in a mixed gas of nitrogen gas or NX gas, hydrocarbon gas and ammonia gas.
がり軸受である請求項1記載の機械部品。3. The mechanical component according to claim 1, wherein the mechanical component is a constant velocity universal joint or a rolling bearing.
れ用鋼が、少なくとも、Cを0.50〜0.70%と、
Siを単独で若しくはAlを単独で又はSi及びAlの
総量を0.5〜1.0%と、を含有して成る鋼である請
求項1記載の機械部品。4. The structural medium carbon induction hardening steel of the outer casing member has at least C of 0.50 to 0.70%,
The mechanical part according to claim 1, wherein the steel is a steel containing Si alone, Al alone, or a total amount of 0.5 to 1.0% of Si and Al.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4078888A JP3047088B2 (en) | 1992-02-28 | 1992-02-28 | Machine parts having rolling elements |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4078888A JP3047088B2 (en) | 1992-02-28 | 1992-02-28 | Machine parts having rolling elements |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH05240253A JPH05240253A (en) | 1993-09-17 |
JP3047088B2 true JP3047088B2 (en) | 2000-05-29 |
Family
ID=13674353
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JP4078888A Expired - Lifetime JP3047088B2 (en) | 1992-02-28 | 1992-02-28 | Machine parts having rolling elements |
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JP4529214B2 (en) * | 2000-01-20 | 2010-08-25 | 株式会社ジェイテクト | Thrust roller bearing |
JP2002213137A (en) * | 2001-01-22 | 2002-07-31 | Tashiko:Kk | Hanger roller unit |
US7685717B2 (en) | 2002-05-14 | 2010-03-30 | Jtekt Corporation | Method for manufacturing a bearing raceway member |
CA2636103C (en) | 2006-01-18 | 2014-06-10 | Smith & Nephew, Inc. | Applications of diffusion hardening techniques |
JP2010014473A (en) * | 2008-07-02 | 2010-01-21 | Ntn Corp | Detection method of detecting temporal change generated when contact fatigue damage is generated |
JP2010014474A (en) * | 2008-07-02 | 2010-01-21 | Ntn Corp | Detection method for detecting state of occurrence of contact fatigue damage on fixed type constant velocity universal joint |
JP5679543B2 (en) * | 2010-03-29 | 2015-03-04 | Ntn株式会社 | Bearing parts and bearings |
JP6026915B2 (en) | 2013-02-13 | 2016-11-16 | Ntn株式会社 | Inspection method for bearing parts and rolling bearings |
-
1992
- 1992-02-28 JP JP4078888A patent/JP3047088B2/en not_active Expired - Lifetime
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