JP2005098320A - Bearing apparatus for supporting wheel - Google Patents

Bearing apparatus for supporting wheel Download PDF

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JP2005098320A
JP2005098320A JP2003330125A JP2003330125A JP2005098320A JP 2005098320 A JP2005098320 A JP 2005098320A JP 2003330125 A JP2003330125 A JP 2003330125A JP 2003330125 A JP2003330125 A JP 2003330125A JP 2005098320 A JP2005098320 A JP 2005098320A
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Prior art keywords
inner ring
hub
diameter
small
ring raceway
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Susumu Tanaka
進 田中
Yuji Miyamoto
裕司 宮本
Hideyuki Uyama
英幸 宇山
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NSK Ltd
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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
    • F16C43/00—Assembling bearings
    • F16C43/04—Assembling rolling-contact bearings
    • 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
    • F16C33/583—Details of specific parts of races
    • 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
    • F16C19/14—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load
    • F16C19/18—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls
    • F16C19/181—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact
    • F16C19/183—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact with two rows at opposite angles
    • F16C19/184—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact with two rows at opposite angles in O-arrangement
    • F16C19/186—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with angular contact with two rows at opposite angles in O-arrangement with three raceways provided integrally on parts other than race rings, e.g. third generation hubs
    • 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
    • F16C2326/00—Articles relating to transporting
    • F16C2326/01—Parts of vehicles in general
    • F16C2326/02—Wheel hubs or castors

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Support Of The Bearing (AREA)
  • Rolling Contact Bearings (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To furthermore improve the reliability of a bearing apparatus by furthermore improving the delayed fracture strength without lowering the rolling life of the bearing. <P>SOLUTION: The bearing apparatus 1 for supporting a wheel is configured such that an inner race 3 is connected and fixed to a hub 2 by pressing the inner race 3 against the stepped surface 8a of a small diameter stepped portion 8 by fixing the inner race 3 by caulking a cylindrical portion 9 so as to expand in the radially outward direction, the cylindrical portion 9 being formed so as to protrude from the inner race 3 fitted on the small diameter stepped portion 8 on the inner end side of the hub 2. The inner race 3 made of a carburized steel is treated by carburizing or carbonitriding, and then is hardened, and then is tempered by heating and holding it to 200 to 300°C. As a result, the hardness of the surface of the inner race becomes 60 to 63 HRC, and the amount of the retained austenite of the surface layer becomes 10 to 25%, and the amount of the average retained austenite becomes at most 3%, and further the hoop stress on the surface of the outside diameter portion or the small diameter portion inside the surface of the outside diameter portion is set at 300 MPa or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、例えば自動車等の車輪を懸架装置に対して回転自在に支持するための車輪支持用軸受装置に関する。   The present invention relates to a wheel support bearing device for rotatably supporting a wheel of, for example, an automobile with respect to a suspension device.

従来のこの種の車輪支持用軸受装置としては、例えば図１に示すものが知られている。この車輪支持用軸受装置１は、ハブ２、内輪３、外輪４及び複数の転動体５を備えており、ハブ２の外端部（自動車への組み付け状態で車幅方向外側の端部：図１の左端部）の外周面には、車輪を支持するための車輪取付用フランジ６が設けられている。
また、ハブ２の内端部（図１の右端部）には小径段部８が形成されており、該小径段部８に嵌め込まれた内輪３の外周面及びハブ２の軸方向の中間部外周面にはそれぞれ軌道面が形成されて複列の内輪軌道面７ａ，７ｂとされている。ハブ２の内端部側には円筒部９が前記内輪３から突出して形成されており、該円筒部９を直径方向外方に拡げて前記内輪３を加締めることにより該内輪３を前記小径段部８の段差面８ａに軸方向に押さえつけて前記ハブ２に結合固定している（例えば特許文献１参照）。 As a conventional wheel support bearing device of this type, for example, the one shown in FIG. 1 is known. The wheel support bearing device 1 includes a hub 2, an inner ring 3, an outer ring 4, and a plurality of rolling elements 5, and an outer end portion of the hub 2 (an end portion on the outer side in the vehicle width direction in an assembled state on an automobile: FIG. 1 is provided with a wheel mounting flange 6 for supporting the wheel.
Further, a small-diameter step portion 8 is formed at the inner end portion (right end portion in FIG. 1) of the hub 2, and the outer peripheral surface of the inner ring 3 fitted in the small-diameter step portion 8 and the intermediate portion in the axial direction of the hub 2. A raceway surface is formed on each outer peripheral surface to form double-row inner ring raceway surfaces 7a and 7b. A cylindrical portion 9 is formed on the inner end side of the hub 2 so as to protrude from the inner ring 3, and the inner ring 3 is tightened to the small diameter by expanding the cylindrical portion 9 outward in the diameter direction. It is pressed against the step surface 8a of the step portion 8 in the axial direction and coupled and fixed to the hub 2 (see, for example, Patent Document 1).

外輪４の内周面には前記複列の内輪軌道面７ａ，７ｂに対応する複列の外輪軌道面１０ａ，１０ｂが形成されており、また、外輪４の前記車輪取付用フランジ６から離間する側の端部には懸架装置取付用フランジ１１が設けられている。そして、複列の内輪軌道面７ａ，７ｂと複列の外輪軌道面１０ａ，１０ｂとの間にそれぞれ複数の転動体５が転動可能に配設されている。
尚、図示の例では、転動体５として玉を使用しているが、重量の嵩む車輪支持用軸受装置の場合には、転動体５としてテーパころを使用する場合もある。
上述の様な車輪支持用軸受装置１を自動車に組み付けるには、外輪４の懸架装置取付用フランジ１１を懸架装置に固定し、ハブ２の車輪取付用フランジ６に車輪を固定する。これにより、車輪を懸架装置に対して回転自在に支持することができる。
特開２００１−２４２１８８号公報 Double row outer ring raceway surfaces 10 a and 10 b corresponding to the double row inner ring raceway surfaces 7 a and 7 b are formed on the inner peripheral surface of the outer ring 4, and are spaced apart from the wheel mounting flange 6 of the outer ring 4. A suspension device mounting flange 11 is provided at the end on the side. A plurality of rolling elements 5 are arranged so as to roll between the double row inner ring raceway surfaces 7a and 7b and the double row outer ring raceway surfaces 10a and 10b.
In the illustrated example, a ball is used as the rolling element 5, but a tapered roller may be used as the rolling element 5 in the case of a heavy wheel support bearing device.
In order to assemble the wheel support bearing device 1 as described above to the automobile, the suspension device mounting flange 11 of the outer ring 4 is fixed to the suspension device, and the wheel is fixed to the wheel mounting flange 6 of the hub 2. Thereby, a wheel can be rotatably supported with respect to a suspension apparatus.
JP 2001-242188 A

上記従来の車輪支持用軸受装置においては、ハブ２に設けられた円筒部９を直径方向外方に拡げて前記内輪３を加締める加締め部９ａを形成する際には、円筒部９に対して直径方向外方に向く大きな荷重を付与する必要があるため、内輪３（特に、内輪３の内周面及び加締め部側端面）には、加締め部９ａからの円周方向への比較的大きな引張り応力が作用する。このため、ハブ２の材料としては、塑性加工が容易で、且つ必要部分には高周波焼入れ等により硬化層を付与することが可能な機械構造用炭素鋼（Ｓ５３Ｃ，Ｓ５５Ｃ等）が用いられ、内輪３の材料としては、加締め応力に対して十分な強度を有し、且つ十分な転がり疲労寿命を有する高炭素クロム軸受鋼（ＳＵＪ２，ＳＵＪ３等）が主として用いられている。   In the conventional wheel support bearing device, when the cylindrical portion 9 provided on the hub 2 is expanded outward in the diameter direction to form the crimped portion 9a for crimping the inner ring 3, the cylindrical portion 9 Therefore, the inner ring 3 (particularly, the inner circumferential surface of the inner ring 3 and the crimping portion side end surface) is compared with the circumferential direction from the crimped portion 9a. Large tensile stress acts. Therefore, as the material of the hub 2, carbon steel for mechanical structure (S53C, S55C, etc.) that can be easily plastically processed and can be provided with a hardened layer by induction hardening or the like is used. As the material No. 3, high carbon chromium bearing steel (SUJ2, SUJ3, etc.) having a sufficient strength against caulking stress and a sufficient rolling fatigue life is mainly used.

なお、加締め作業後においては、内輪３のクリープ防止及び寿命確保やガタの発生による異音、転動体の乗り上げ防止等の観点から、内輪３には適当なフープ応力と転動体５には適正な予圧が付与される。
ところで、一般に、高強度部材においては、荷重が負荷されてからある時間経過後に突然破壊を生じる遅れ破壊と呼ばれる現象があることが知られている。特に、引張り強度が１．２ＧＰａ以上、硬さではＨＲＣ４０以上の場合に、遅れ破壊感受性が増加するとされており、例えば、１．５〜２ＧＰａ級の高強度鋼であれば、水中１００時間での遅れ破壊強度は、１／３〜１／４にまで低下するとの報告がある（松山晋作著、遅れ破壊、図４．１、日本工業新聞社、１９８９）。 In addition, after the caulking work, appropriate hoop stress suitable for the inner ring 3 and appropriate for the rolling element 5 from the viewpoints of preventing creep of the inner ring 3 and ensuring the service life, preventing abnormal noise due to play, and preventing the rolling element from climbing up, etc. Preload is applied.
By the way, it is generally known that a high strength member has a phenomenon called delayed fracture that suddenly breaks after a certain time has elapsed since a load is applied. In particular, when the tensile strength is 1.2 GPa or more and the hardness is HRC 40 or more, the delayed fracture susceptibility increases. For example, a high strength steel of 1.5 to 2 GPa class can be used in 100 hours in water. There is a report that the delayed fracture strength decreases to 1/3 to 1/4 (Matsuyama Sakusaku, delayed fracture, FIG. 4.1, Nihon Kogyo Shimbun, 1989).

車輪支持用軸受装置は、軸受寿命の観点から、泥水やダスト等が軸受内部へ侵入しないように、駆動輪にあってはハブシールにより、従動輪においてはハブシールおよび蓋体によりシーリングされ、これらの侵入を防止するよう対策が施されているため、実際には、遅れ破壊が問題になるようなことは極めて少ないが、極度の腐食環境に曝されるような場合を考慮するとより高い信頼性が求められる。
遅れ破壊は、静的な荷重下で腐食等の影響により鋼中に水素侵入が認められる場合に生じる現象であり、静的荷重とは、この場合、内輪３に付与されたフープ応力がそれに該当する。 From the viewpoint of bearing life, the wheel support bearing device is sealed with a hub seal in the drive wheel and a hub seal and lid in the driven wheel so that muddy water and dust do not enter the bearing. In fact, there are very few cases where delayed fracture becomes a problem, but higher reliability is required in consideration of exposure to extremely corrosive environments. It is done.
Delayed fracture is a phenomenon that occurs when hydrogen intrusion is observed in steel under the influence of corrosion under static load. In this case, hoop stress applied to the inner ring 3 corresponds to static load. To do.

遅れ破壊を防止するためには、上記静的荷重を負荷しないのであれば生じることはないが、車輪支持用軸受装置の内輪３の場合には、軸受寿命の確保やガタや玉の乗り上げ防止及びクリープ防止等のため、適正な予圧とフープ応力を付与する必要があるため、構造上静的荷重をゼロにすることは困難である。
本発明はこのような技術的背景を鑑みてなされたものであり、寸法安定性を高める処理を施すとともに、内輪の加締めによるフープ応力を適正化することにより、転がり寿命を低下させることなく、遅れ破壊強度をさらに高めて信頼性のより向上を図ることができる車輪支持用軸受装置を提供することを目的とする。 In order to prevent delayed fracture, it does not occur unless the static load is applied. However, in the case of the inner ring 3 of the wheel support bearing device, it is possible to ensure the bearing life and prevent the rattling and balls from climbing. In order to prevent creep and the like, it is necessary to apply appropriate preload and hoop stress, so it is difficult to make the static load zero due to the structure.
The present invention has been made in view of such a technical background, and performs processing for improving dimensional stability, and by optimizing the hoop stress due to caulking of the inner ring, without reducing the rolling life, An object of the present invention is to provide a wheel support bearing device capable of further improving the reliability by increasing the delayed fracture strength.

本発明者等は、車輪支持用軸受装置の内輪が加締められることによるフープ応力と遅れ破壊強度との相関について調査し、転がり寿命を確保しつつ、内輪割れに対する信頼性をさらに高めることができないかを鋭意検討した結果、本発明を完成するに至った。
即ち、上記目的を達成するために、請求項１に係る発明は、内端部に小径段部が形成されると共に軸方向の中間部外周面に内輪軌道面が形成されたハブと、前記小径段部に外嵌されると共に外周面に内輪軌道面が形成された内輪と、前記ハブの内輪軌道面及び前記内輪の内輪軌道面に対応する複列の外輪軌道面が形成された外輪と、前記ハブの内輪軌道面及び前記内輪の内輪軌道面と前記複列の外輪軌道面との間に転動自在に配設された複数の転動体と、前記ハブの内端側で前記小径段部に外嵌された前記内輪よりも突出して形成された円筒部とを備え、該円筒部を直径方向外方に拡げて前記内輪を加締めることにより該内輪を前記小径段部の段差面に押さえつけて前記ハブに結合固定した車輪支持用軸受装置において、
前記内輪が、浸炭鋼に浸炭又は浸炭窒化処理を施した後、焼入れを行ない、その後２００〜３００°Ｃに加熱保持して焼戻しを行なうことで、表面硬さがＨＲＣ６０〜６３、表面層の残留オーステナイト量が１０〜２５％、且つ平均残留オーステナイト量が３％以下とされ、更に、外径面又は該外径面の内の小径部のフープ応力が３００ＭＰａ以下に設定されていることを特徴とする。 The present inventors investigated the correlation between hoop stress and delayed fracture strength caused by caulking of the inner ring of the wheel support bearing device, and could not further improve the reliability against inner ring cracking while ensuring the rolling life. As a result of extensive studies, the present invention has been completed.
That is, in order to achieve the above object, the invention according to claim 1 includes a hub in which a small-diameter step portion is formed in an inner end portion and an inner ring raceway surface is formed in an outer circumferential surface in an axial direction, and the small-diameter portion. An inner ring that is externally fitted to the step portion and has an inner ring raceway surface formed on an outer peripheral surface; and an outer ring that has an inner ring raceway surface of the hub and a double row outer ring raceway surface corresponding to the inner ring raceway surface of the inner ring; A plurality of rolling elements arranged to roll freely between the inner ring raceway surface of the hub, the inner ring raceway surface of the inner ring and the outer ring raceway surface of the double row, and the small diameter step portion on the inner end side of the hub A cylindrical portion that protrudes from the inner ring that is externally fitted to the outer ring, and presses the inner ring against the step surface of the small-diameter step portion by expanding the cylindrical portion outward in the diameter direction and crimping the inner ring. In the wheel support bearing device coupled and fixed to the hub,
After the inner ring is subjected to carburizing or carbonitriding treatment on the carburized steel, quenching is performed, and then heating and holding is performed at 200 to 300 ° C., so that the surface hardness is HRC 60 to 63, and the surface layer remains. The austenite amount is 10 to 25%, the average retained austenite amount is 3% or less, and the hoop stress of the outer diameter surface or the small diameter portion of the outer diameter surface is set to 300 MPa or less. To do.

請求項２に係る発明は、請求項１において、前記内輪の外径面と前記加締め部側端面とのエッジ部が前記外径面側及び前記端面側でそれぞれ両方向に１．０ｍｍ以上のＲ形状となるように加工されていることを特徴とする。   According to a second aspect of the present invention, in the first aspect, an edge portion between the outer diameter surface of the inner ring and the crimped portion side end surface has an R of 1.0 mm or more in both directions on the outer diameter surface side and the end surface side, respectively. It is processed so as to have a shape.

本発明によれば、内輪に浸炭鋼を用い、且つ寸法安定性を高める処理を施すとともに、内輪のフープ応力を適正化することにより、転がり寿命を低下させることなく、遅れ破壊強度を更に高めることが可能となるため、装置全体の信頼性の更なる向上を図ることができる。   According to the present invention, carburized steel is used for the inner ring, and the dimensional stability is increased, and the hoop stress of the inner ring is optimized to further increase the delayed fracture strength without reducing the rolling life. Therefore, the reliability of the entire apparatus can be further improved.

以下、本発明の実施の形態の一例を図を参照して説明する。なお、この実施の形態の車輪支持用軸受装置は、その基本的構成が図１で説明したものと同一であるため、図１を流用して説明する。
本発明の実施の形態の一例である車輪支持用軸受装置は、図１を参照して、ハブ２の内端側で小径段部８に外嵌された内輪３よりも突出して形成された円筒部９を直径方向外方に拡げて内輪３を加締めることにより該内輪３を小径段部８の段差面８ａに押さえつけてハブ２に結合固定するようにしたもので、内輪３が、浸炭鋼に浸炭又は浸炭窒化処理を施した後、焼入れを行ない、その後２００〜３００°Ｃに加熱保持して焼戻しを行なうことで、表面硬さがＨＲＣ６０〜６３、表面層の残留オーステナイト量が１０〜２５％、且つ平均残留オーステナイト量が３％以下とされ、更に、外径面又は該外径面の内の小径部のフープ応力が３００ＭＰａ以下に設定されている。
また、内輪３の外径面と加締め部９ａ側端面とのエッジ部１２が前記外径面側及び前記端面側でそれぞれ１．０ｍｍ以上のＲ形状となるように加工されている（図２及び図３参照）。 Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. The wheel support bearing device of this embodiment has the same basic configuration as that described with reference to FIG. 1, and therefore will be described with reference to FIG.
A wheel support bearing device as an example of an embodiment of the present invention is a cylinder formed so as to protrude from an inner ring 3 that is externally fitted to a small-diameter step portion 8 on the inner end side of a hub 2 with reference to FIG. The inner ring 3 is pressed against the step surface 8a of the small-diameter step portion 8 to be fixedly coupled to the hub 2 by expanding the portion 9 outward in the diameter direction and crimping the inner ring 3. The inner ring 3 is made of carburized steel. After carburizing or carbonitriding the steel, it is quenched and then tempered by heating and holding at 200 to 300 ° C., so that the surface hardness is HRC 60 to 63 and the amount of retained austenite of the surface layer is 10 to 25 %, The average retained austenite amount is 3% or less, and the hoop stress of the outer diameter surface or the small diameter portion of the outer diameter surface is set to 300 MPa or less.
Moreover, the edge part 12 of the outer diameter surface of the inner ring 3 and the crimping part 9a side end surface is processed so as to have an R shape of 1.0 mm or more on the outer diameter surface side and the end surface side, respectively (FIG. 2). And FIG. 3).

次に、本発明の数値等の臨界的意義について説明する。
［内輪３が、浸炭鋼に浸炭又は浸炭窒化処理を施した後、焼入れを行ない、その後２００〜３００°Ｃに加熱保持して焼戻しを行なうことで、表面硬さがＨＲＣ６０〜６３、表面層の残留オーステナイト量が１０〜２５％、且つ平均残留オーステナイト量が３％以下とされ、更に、外径面又は該外径面の内の小径部のフープ応力が３００ＭＰａ以下に設定されている］
ハブ２の小径段部８に内輪３を外嵌固定した後、内輪３よりも突出した部分に形成した円筒部９を直径方向外方に加締め広げることで加締め部９ａを形成するが、加締め部９ａの形成作業に伴なって、直径方向外方に向く大きな荷重を付与する必要がある。 Next, the critical significance of the numerical values of the present invention will be described.
[After the inner ring 3 is carburized or carbonitrided to the carburized steel, it is quenched and then tempered by heating and holding at 200 to 300 ° C., so that the surface hardness is HRC 60 to 63, The retained austenite amount is 10 to 25%, the average retained austenite amount is 3% or less, and the hoop stress of the outer diameter surface or the small diameter portion of the outer diameter surface is set to 300 MPa or less.
After the inner ring 3 is fitted and fixed to the small-diameter step portion 8 of the hub 2, the cylindrical portion 9 formed at a portion protruding from the inner ring 3 is caulked and spread outward in the diametrical direction, thereby forming the caulking portion 9 a. Along with the forming operation of the crimped portion 9a, it is necessary to apply a large load directed outward in the diameter direction.

そのため、内輪３、特に、内輪３の内周面及び加締め部９ａ側端面には、加締め部９ａからの円周方向への比較的大きな引張り応力が作用する。また、加締め荷重を除荷した後は、軸受寿命の確保あるいはガタ、転動体５の乗り上げ等を防止するための適当な予圧と内輪３のクリープ防止を目的とした適正なフープ応力として内輪３に付与される。
転動体５に付与される予圧が不十分であると、軸受寿命が低下したり、ガタ、乗り上げ等を生じやすくなる。また、この予圧が大きすぎても、軸受寿命の低下又は焼付きの原因となる場合がある。そのため一般には、負すきまとなるように、所望の予圧が予め付与される。 Therefore, relatively large tensile stress in the circumferential direction from the caulking portion 9a acts on the inner ring 3, particularly the inner circumferential surface of the inner ring 3 and the end surface on the caulking portion 9a side. In addition, after the caulking load is removed, the inner ring 3 has an appropriate preload for securing the bearing life or preventing backlash and rolling of the rolling element 5, and an appropriate hoop stress for preventing the inner ring 3 from creeping. To be granted.
If the preload applied to the rolling elements 5 is insufficient, the bearing life will be reduced, and play and riding will be likely to occur. Moreover, even if this preload is too large, it may cause a decrease in bearing life or seizure. Therefore, in general, a desired preload is applied in advance so as to provide a negative clearance.

また、内輪３は、ハブ２の小径段部８との嵌め合い及び加締め加工によって適正なフープ応力が付与される。このフープ応力が不十分であると、耐クリープ性が低下し、予圧抜けによるガタが生じやすくなることが懸念される。反面、このフープ応力が大きすぎても、先に述べたように、腐食環境に曝された場合に、内輪３が遅れ破壊を引き起こすことが懸念される。そこで、内輪３には、浸炭鋼を用い、浸炭あるいは浸炭窒化処理後、焼入れ、焼戻しを行う。
具体的には、炭素濃度が０．１〜０．５重量％のクロム鋼やクロムモリブデン鋼等の浸炭鋼を用いる。また、ミクロ偏析帯あるいは粒界に不純物元素が偏析すると、遅れ破壊感受性を増すため、特にＳ及びＰについては、共に０．０２重量％以下とすることが好ましい。
浸炭或いは浸炭窒化処理は、例えば８４０〜９５０°Ｃで、所望の硬化層深さが得られるように数時間処理を行ない、その後、８２０〜８６０°Ｃで焼入れを行うことで実施する。 The inner ring 3 is given an appropriate hoop stress by fitting with the small-diameter step portion 8 of the hub 2 and by caulking. If the hoop stress is insufficient, there is a concern that creep resistance is lowered and play due to preload loss is likely to occur. On the other hand, even if this hoop stress is too large, as described above, there is a concern that the inner ring 3 may cause delayed fracture when exposed to a corrosive environment. Therefore, carburized steel is used for the inner ring 3, and after carburizing or carbonitriding, quenching and tempering are performed.
Specifically, carburized steel such as chromium steel or chromium molybdenum steel having a carbon concentration of 0.1 to 0.5% by weight is used. Further, when the impurity element segregates in the microsegregation zone or the grain boundary, the delayed fracture susceptibility is increased, so that both S and P are preferably 0.02% by weight or less.
Carburization or carbonitriding is performed by performing a treatment for several hours so that a desired hardened layer depth is obtained, for example, at 840 to 950 ° C., and then performing quenching at 820 to 860 ° C.

焼戻しは、２００〜３００°Ｃに加熱保持することで行ない、硬さあるいはミクロ組織を適正化し、転がり寿命、遅れ破壊強度を確保しつつ、寸法安定性を高める。
２００〜３００°Ｃに加熱保持するのは、特に、心部の残留オーステナイトを分解消失させて、寸法安定性を高めるのと、表面層に残存する残留オーステナイトの熱安定性を高めるためであり、好ましくは、２００〜２４０°Ｃとする。また、オーステナイトは、応力状態ではマルテンサイトに変態する場合があり、この場合、かえって遅れ破壊感受性を高めるが、焼戻し過程で分解されると、ベイナイトに類似した組織を呈し、遅れ破壊強度をより高める作用がある。 Tempering is performed by heating and holding at 200 to 300 ° C., and the hardness or microstructure is optimized to increase the dimensional stability while ensuring the rolling life and delayed fracture strength.
The reason for heating and holding at 200 to 300 ° C. is to improve the thermal stability of the retained austenite remaining in the surface layer, in particular, by decomposing and disappearing the retained austenite at the core and enhancing the dimensional stability. Preferably, the temperature is 200 to 240 ° C. In addition, austenite may be transformed into martensite in the stress state. In this case, it increases delayed fracture susceptibility, but when decomposed in the tempering process, it exhibits a structure similar to bainite and further increases delayed fracture strength. There is an effect.

具体的には、転がり寿命との両立化いう観点から、表面硬さをＨＲＣ６０〜６３、表面層の残留オーステナイト量を１０〜２５％、寸法安定性の観点から、平均残留オーステナイト量を３％以下とする。
ここでの平均残留オーステナイト量は、表面から心部に至るまでの残留オーステナイト量分布を測定し、これを肉厚で平均化した値を意味する。
上記構成によれは、オーステナイトが分解した際の内輪３の変形や寸法膨張が抑制されるため、経時的なフープ応力の減少を抑制できて、ガタや乗り上げ等の発生が生じ難くなる。言い換えれば、内輪３の寸法変化による経時的なフープ応力の減少が抑えられるのであるから、初期に付与するフープ応力の低減が図れる。
また、マルテンサイトの焼戻しによる歪み低減と残留オーステナイトのベイナイト化等によって遅れ破壊感受性を低減でき、しかも、表面硬さ及び表面残留オーステナイト量が軸受鋼と遜色ない程度に確保されているため、軸受寿命が低下することがない。 Specifically, from the viewpoint of making the rolling life compatible, the surface hardness is HRC 60 to 63, the residual austenite amount of the surface layer is 10 to 25%, and the average residual austenite amount is 3% or less from the viewpoint of dimensional stability. And
Here, the average retained austenite amount means a value obtained by measuring the retained austenite amount distribution from the surface to the core and averaging the distribution with the thickness.
According to the above configuration, since deformation and dimensional expansion of the inner ring 3 when austenite is decomposed are suppressed, it is possible to suppress a decrease in hoop stress over time, and it is difficult for looseness and riding-up to occur. In other words, since the decrease in the hoop stress over time due to the dimensional change of the inner ring 3 can be suppressed, the hoop stress applied initially can be reduced.
In addition, it is possible to reduce delayed fracture susceptibility by reducing strain due to martensite tempering and bainite of retained austenite, and the surface hardness and surface retained austenite amount are ensured to be comparable to bearing steel, so bearing life Will not drop.

更に、浸炭または浸炭窒化処埋によって、その表面層には、高い圧縮残留応力を付与できるため、高フープ応力下でも十分な転がり寿命と高い内輪割れ強度を有することが可能となる。好ましくは、表面下５０〜１００μｍ深さにおいて、１５０ＭＰａ以上の圧縮残留応力を付与する。
内輪３の最大フープ応力は、外径面あるいは該外径面の内の小径部において３００ＭＰａ以下とする。これより大きいと、転がり寿命が低下したり、著しい腐食環境下に曝された場合には、水素脆性による内輪割れが生じる懸念がある。本発明においては、耐クリープ性の観点から、好ましくは１５０ＭＰａ以上、２５０ＭＰａ以下とする。 Furthermore, since carburizing or carbonitriding treatment can impart a high compressive residual stress to the surface layer, it is possible to have a sufficient rolling life and high inner ring cracking strength even under high hoop stress. Preferably, compressive residual stress of 150 MPa or more is applied at a depth of 50 to 100 μm below the surface.
The maximum hoop stress of the inner ring 3 is set to 300 MPa or less at the outer diameter surface or the small diameter portion of the outer diameter surface. If it is larger than this range, there is a concern that the rolling life is reduced or the inner ring cracks due to hydrogen embrittlement when exposed to a severe corrosive environment. In the present invention, from the viewpoint of creep resistance, it is preferably 150 MPa or more and 250 MPa or less.

［内輪３の外径面と加締め部９ａ側端面とのエッジ部１２が前記外径面側及び前記端面側でそれぞれ１．０ｍｍ以上のＲ形状となるように加工］
ハブ２の小径段部８に内輪３を外嵌固定した後、内輪３よりも突出した部分に形成した円筒部９を直径方向外方に加締め広げることで加締め部９ａを形成するが、加締め部９ａの形成作業に伴なって、直径方向外方に向く大きな荷重を付与する必要がある。そのため、内輪３、特に、内輪３の内周面及び加締め部側端面には、加締め部９ａからの円周方向への比較的大きな引張り応力が作用する。また、この引張り応力は、加締め荷重を除荷した後は、軸受寿命あるいはガタ、転動体５の乗り上げ等を防止するための適当な予圧と内輪のクリープ防止を目的とした適正なフープ応力として内輪３に付与される。 [Processing so that the edge portion 12 between the outer diameter surface of the inner ring 3 and the end surface on the caulking portion 9a side has an R shape of 1.0 mm or more on each of the outer diameter surface side and the end surface side]
After the inner ring 3 is fitted and fixed to the small-diameter step portion 8 of the hub 2, the cylindrical portion 9 formed at a portion protruding from the inner ring 3 is caulked and spread outward in the diametrical direction, thereby forming the caulking portion 9 a. Along with the forming operation of the crimped portion 9a, it is necessary to apply a large load directed outward in the diameter direction. Therefore, relatively large tensile stress in the circumferential direction from the caulking portion 9 a acts on the inner ring 3, particularly the inner circumferential surface of the inner ring 3 and the end surface on the caulking portion side. In addition, after removing the caulking load, this tensile stress is an appropriate preload for preventing bearing life or play, rolling of the rolling element 5, etc., and an appropriate hoop stress for the purpose of preventing creep of the inner ring. It is given to the inner ring 3.

遅れ破壊は、静的な荷重下で腐食等の影響により鋼中に水素侵入が認められる場合に生じる現象であり、腐食が問題となるケースでは、このフープ応力が静的荷重に該当することとなる。
引張応力は、本来、加締め部９ａ近傍の内径側が最も大きい値となるが、内径側はハブ２の加締め部９ａで保護されるため、外部環境から腐食等の影響を受けにくく、遅れ破壊の起点とはなりにくい。最も遅れ破壊起点となり易いのは、応力が集中しやすい内輪３の外径面及び加締め部９ａ側端面のエッジ部１２である。特に、小外径部を有する内輪３においては、フープ応力の大きさから、小外径面１３と加締め部９ａ側端面のエッジ部１２が起点となりやすい。エッジ部１２は、焼入れ時の冷却速度が最も大きいため、マルテンサイト変態時に引張りの変態応力が残存しやすいことも起点がエッジ部１２に集中する理由の一つと考えられる。 Delayed fracture is a phenomenon that occurs when hydrogen intrusion is observed in steel under the influence of corrosion under static load. In cases where corrosion is a problem, this hoop stress is considered to be a static load. Become.
The tensile stress is originally the largest value on the inner diameter side in the vicinity of the caulking portion 9a. However, since the inner diameter side is protected by the caulking portion 9a of the hub 2, it is hardly affected by corrosion or the like from the external environment, and is delayed. It is hard to be the starting point of The most likely delayed fracture starting point is the outer diameter surface of the inner ring 3 where stress is likely to concentrate and the edge portion 12 on the end surface on the side of the crimped portion 9a. In particular, in the inner ring 3 having a small outer diameter portion, the small outer diameter surface 13 and the edge portion 12 of the end surface on the side of the crimped portion 9a are likely to start from the magnitude of the hoop stress. Since the edge portion 12 has the highest cooling rate at the time of quenching, it is considered that one of the reasons that the starting point concentrates on the edge portion 12 is that tensile transformation stress tends to remain during martensitic transformation.

そこで、図２及び図３に示すように、この内輪３の加締め部９ａ側の小外径面１３を含む外径面と加締め部９ａ側端面とのエッジ部１２を、前記小外径面１３を含む外径面側（図２のＸ方向）及び前記端面側（図２のＹ方向）で両方向にそれぞれ１．０ｍｍ以上（好ましくは、外径面側で１．５ｍｍ以上、端面側で１．０ｍｍ以上）のＲ形状となるように加工することにより、変態応力あるいは加締め加工により付与されたエッジ部１２への引張応力の集中を軽減でき、遅れ破壊強度を高めることが可能となる。   Therefore, as shown in FIGS. 2 and 3, the edge portion 12 between the outer diameter surface including the small outer diameter surface 13 of the inner ring 3 on the caulking portion 9a side and the end surface on the caulking portion 9a side, 1.0 mm or more in both directions on the outer diameter surface side (X direction in FIG. 2) including the surface 13 and the end surface side (Y direction in FIG. 2) (preferably 1.5 mm or more on the outer diameter surface side, end surface side) By processing to have a round shape of 1.0 mm or more), it is possible to reduce the concentration of tensile stress on the edge portion 12 applied by transformation stress or caulking, and to increase delayed fracture strength Become.

種々のエッジ部形状を有する内輪に対して種々の条件下で加締め加工を行なった従動輪支持用軸受装置（基本的構造は図１と同様）を用いて転がり寿命試験及び遅れ破壊強度試験を行った。なお、内輪には、φ２６ｍｍの小外径面を有する段付き内輪を用いた。小外径面及び加締め部側端面とのエッジ部は、０．５Ｒの場合に、次に述べる遅れ破壊強度試験において、割れ発生確率が高くなる傾向が認められたため、小外径面側Ｘを１．５ｍｍ、加締め部端面側Ｙを１．０ｍｍとし、Ｒ状に加工したものを使用した。
表１に、評価に用いた内輪の材料成分及び熱処理条件を示した。表中には、表面硬さ、５０〜１００μｍ深さにおける表面残留オーステナイト量、平均残留オーステナイト量も併記した。
また、表１記載の各内輪を用いて、前記内輪にフープ応力を任意に変えながら種々の条件下で加締め加工行なった。なお、フープ応力は、小外径面円周方向に歪みゲージを貼り付け応力値（σ＝Ｅ・ε）を求めた。 Rolling life test and delayed fracture strength test using a bearing device for supporting a driven wheel (basic structure is the same as that shown in Fig. 1) that has been swaged under various conditions on an inner ring having various edge shapes. went. As the inner ring, a stepped inner ring having a small outer diameter surface of φ26 mm was used. In the case of 0.5R, the edge portion between the small outer diameter surface and the crimped portion side end surface has a tendency to increase the probability of occurrence of cracks in the delayed fracture strength test described below. Was 1.5 mm, the crimped portion end face side Y was 1.0 mm, and processed into an R shape.
Table 1 shows the inner ring material components and heat treatment conditions used in the evaluation. In the table, the surface hardness, the amount of surface retained austenite at a depth of 50 to 100 μm, and the amount of average retained austenite are also shown.
In addition, each inner ring shown in Table 1 was subjected to crimping under various conditions while arbitrarily changing the hoop stress on the inner ring. For the hoop stress, a strain gauge was attached in the circumferential direction of the small outer diameter surface, and the stress value (σ = E · ε) was obtained.

Figure 2005098320
Figure 2005098320

次に、加締め加工を行なった各軸受装置に対して、以下の条件で、遅れ破壊強度試験を行った。また、内輪の耐クリープ性については、内輪単体で１５０°Ｃに５００時間保持し、内輪内径の膨張量を測定して得られる寸法変化率により評価した。なお、転がり寿命については、６２０６深溝玉軸受を別途製作し、以下の条件で評価した。この場合のフープ応力は、シャフト径を適当なものに変えることで設定し、残留すきまは、０〜６μｍ程度とした。なお、フープ応力値は、上記同様、歪みゲージを内輪肩部円周方向に貼り付けることで求めた。
（転がり寿命試験）
回転速度：３９００ｍｉｎ-1
荷重 ：１３８２０Ｎ
軸受温度：６５°Ｃ
試験時間：１０００ｈｒ Next, a delayed fracture strength test was performed on each bearing device subjected to the caulking process under the following conditions. Further, the creep resistance of the inner ring was evaluated based on the dimensional change rate obtained by holding the inner ring alone at 150 ° C. for 500 hours and measuring the expansion amount of the inner ring inner diameter. For the rolling life, a 6206 deep groove ball bearing was separately manufactured and evaluated under the following conditions. The hoop stress in this case was set by changing the shaft diameter to an appropriate one, and the residual clearance was about 0 to 6 μm. In addition, the hoop stress value was calculated | required by sticking a strain gauge in the inner ring | wheel shoulder part circumferential direction like the above.
(Rolling life test)
Rotational speed: 3900 min -1
Load: 13820N
Bearing temperature: 65 ° C
Test time: 1000hr

（遅れ破壊強度試験）
本軸受装置には、通常、ハブシール及び蓋体が装着され、軸受内部へ水や泥水が浸入しないような構造となっているが、今回は、これらをすべて装着しないで、且つグリース等も封入しない状態で水道水に浸漬した。
その結果、今回評価した全ての軸受装置において、水道水２００時間浸漬した場合においても内輪は割損しなかった。そこで、以下の条件で同様の浸漬試験を実施した。なお、本試験条件は、プレストレスコンクリートに用いられる鋼線、鋼棒（以下、ＰＣ鋼と称する）の水素による遅れ破壊を評価する標準試験と同一であって、実際の環境を再現するものではないが、重要な一因子である水素脆性を評価できる有効な手法である。
試験溶液：２０％チオシアン酸アンモニウム水溶液（ＮＨ4 ＣＮＳ）
試験条件
温度 ：５０°Ｃ±１°Ｃ
試験時間：２００時間打ち切り
表２に上記試験結果を示す。 (Delayed fracture strength test)
This bearing device is usually equipped with a hub seal and lid so that water and muddy water do not enter inside the bearing. However, this time, all of them are not installed and grease is not sealed. It was immersed in tap water in the state.
As a result, in all the bearing devices evaluated this time, the inner ring did not break even when immersed in tap water for 200 hours. Therefore, a similar immersion test was performed under the following conditions. This test condition is the same as the standard test for evaluating delayed fracture due to hydrogen of steel wires and steel bars (hereinafter referred to as PC steel) used for prestressed concrete, and does not reproduce the actual environment. Although it is not, it is an effective method that can evaluate hydrogen embrittlement, which is an important factor.
Test solution: 20% ammonium thiocyanate aqueous solution (NH 4 CNS)
Test condition temperature: 50 ° C ± 1 ° C
Test time: 200 hours censored Table 2 shows the test results.

Figure 2005098320
Figure 2005098320

実施例１〜１０が本発明例であり、比較例１〜５が本発明例に対する比較例である。実施例１〜１０の本発明例においては、浸炭または浸炭窒化処理後に、焼入れを行ない、その後、寸法安定性を高める焼戻し処理を施しているため、転がり寿命が十分確保でき、且つ比較例に対して寸法変化が少ないため、耐クリープ性に優れる。また、上記に述べた理由により遅れ破壊強度（割れ寿命）においても優れている。
比較例１は、従来ＳＵＪ２の例であるが、遅れ破壊強度及び耐クリープ性の点で本発明例よりも劣っている。また、比較例２はＳＵＪ２の残留オーステナイトを焼戻しにより分解消失させた場合の例であるが、硬さが低下したことによりやや寿命が低下した。
比較例３、４は、通常の浸炭処理を施した場合の例であるが、残留オーステナイト量が多く、寸法安定性が劣る他、遅れ破壊強度においても本発明例よりも劣っている。 Examples 1 to 10 are examples of the present invention, and Comparative Examples 1 to 5 are comparative examples for the examples of the present invention. In Examples 1 to 10 of the present invention, after carburizing or carbonitriding, quenching is performed, and then tempering is performed to improve dimensional stability, so that a sufficient rolling life can be secured, and for the comparative example Excellent crease resistance due to small dimensional change. Moreover, it is excellent also in delayed fracture strength (crack life) for the reasons described above.
Comparative Example 1 is an example of conventional SUJ2, but is inferior to the inventive example in terms of delayed fracture strength and creep resistance. Moreover, although the comparative example 2 is an example when the residual austenite of SUJ2 is decomposed and lost by tempering, the life is slightly reduced due to the decrease in hardness.
Comparative Examples 3 and 4 are examples in the case where normal carburizing treatment is performed, but the amount of retained austenite is large, the dimensional stability is inferior, and the delayed fracture strength is also inferior to that of the present invention.

比較例５は、フープ応力が４００ＭＰａと高く、寿命、遅れ破壊強度共に低下した。 図４にフープ応力と転がり寿命との関係を、図５にフープ応力と割れ寿命（遅れ破壊強度）との関係をそれぞれ示す。各図中●は本発明例を示し、○は比較例を示している。各図から判るように、いずれの場合も本発明例の方が優れていることが確認できる。また、フープ応力が３００ＭＰａを超えると寿命低下の傾向が確認されるため、好ましいフープ応力は３００ＭＰａ以下とするのが良い。本発明例においては、内輪の膨張による寸法変化がなく、内輪膨張に起因した経時的な耐クリープ性の低下がないため、フープ応力をさらに低減することが可能であり、より好ましくは２５０ＭＰａ以下とする。   In Comparative Example 5, the hoop stress was as high as 400 MPa, and both the life and delayed fracture strength were reduced. FIG. 4 shows the relationship between hoop stress and rolling life, and FIG. 5 shows the relationship between hoop stress and crack life (delayed fracture strength). In each figure, ● represents an example of the present invention, and ○ represents a comparative example. As can be seen from each figure, it can be confirmed that the present invention is superior in any case. Moreover, since the tendency for a life fall will be confirmed when hoop stress exceeds 300 Mpa, it is good that a preferable hoop stress shall be 300 Mpa or less. In the example of the present invention, there is no dimensional change due to the expansion of the inner ring, and there is no decrease in creep resistance over time due to the expansion of the inner ring, so that the hoop stress can be further reduced, and more preferably 250 MPa or less. To do.

車輪支持用軸受装置の一例を示す一部を破断した図である。It is the figure which fractured | ruptured a part which shows an example of the bearing apparatus for wheel support. エッジ部の拡大図である。It is an enlarged view of an edge part. （ａ）はエッジ部のＲ形状の一例を示す断面図、（ｂ）はエッジ部のＲ形状の他の例を示す断面図である。(A) is sectional drawing which shows an example of R shape of an edge part, (b) is sectional drawing which shows the other example of R shape of an edge part. フープ応力と転がり寿命との関係を示すグラフ図である。It is a graph which shows the relationship between hoop stress and rolling life. フープ応力と割れ寿命との関係を示すグラフ図である。It is a graph which shows the relationship between hoop stress and a crack life.

符号の説明Explanation of symbols

２ ハブ
３ 内輪
４ 外輪
５ 転動体
７ａ 内輪軌道面
７ｂ 内輪軌道面
８ 小径段部
８ａ 段差面
９ 円筒部
９ａ 加締め部
１０ａ 外輪軌道面
１０ｂ 外輪軌道面 2 Hub 3 Inner ring 4 Outer ring 5 Rolling element 7a Inner ring raceway surface 7b Inner ring raceway surface 8 Small-diameter stepped portion 8a Stepped surface 9 Cylindrical portion 9a Caulking portion 10a Outer ring raceway surface 10b Outer ring raceway surface

Claims (2)

内端部に小径段部が形成されると共に軸方向の中間部外周面に内輪軌道面が形成されたハブと、前記小径段部に外嵌されると共に外周面に内輪軌道面が形成された内輪と、前記ハブの内輪軌道面及び前記内輪の内輪軌道面に対応する複列の外輪軌道面が形成された外輪と、前記ハブの内輪軌道面及び前記内輪の内輪軌道面と前記複列の外輪軌道面との間に転動自在に配設された複数の転動体と、前記ハブの内端側で前記小径段部に外嵌された前記内輪よりも突出して形成された円筒部とを備え、該円筒部を直径方向外方に拡げて前記内輪を加締めることにより該内輪を前記小径段部の段差面に押さえつけて前記ハブに結合固定した車輪支持用軸受装置において、
前記内輪が、浸炭鋼に浸炭又は浸炭窒化処理を施した後、焼入れを行ない、その後２００〜３００°Ｃに加熱保持して焼戻しを行なうことで、表面硬さがＨＲＣ６０〜６３、表面層の残留オーステナイト量が１０〜２５％、且つ平均残留オーステナイト量が３％以下とされ、更に、外径面又は該外径面の内の小径部のフープ応力が３００ＭＰａ以下に設定されていることを特徴とする車輪支持用軸受装置。 A hub in which a small-diameter step portion is formed at the inner end and an inner ring raceway surface is formed on the outer peripheral surface in the axial direction, and an inner ring raceway surface is formed on the outer peripheral surface while being fitted around the small-diameter step portion. An inner ring, an outer ring formed with a double row outer ring raceway surface corresponding to the inner ring raceway surface of the hub and the inner ring raceway surface of the inner ring, an inner ring raceway surface of the hub, an inner ring raceway surface of the inner ring, and the double row A plurality of rolling elements that are rotatably arranged between the outer ring raceway surface and a cylindrical portion that is formed on the inner end side of the hub so as to protrude from the inner ring that is externally fitted to the small-diameter stepped portion; A wheel support bearing device in which the cylindrical portion is expanded outward in the diameter direction and the inner ring is crimped to press the inner ring against the step surface of the small-diameter stepped portion and coupled and fixed to the hub.
After the inner ring is subjected to carburizing or carbonitriding treatment on the carburized steel, quenching is performed, and then heating and holding is performed at 200 to 300 ° C., so that the surface hardness is HRC 60 to 63, and the surface layer remains. The austenite amount is 10 to 25%, the average retained austenite amount is 3% or less, and the hoop stress of the outer diameter surface or the small diameter portion of the outer diameter surface is set to 300 MPa or less. Wheel support bearing device. 前記内輪の外径面と前記加締め部側端面とのエッジ部が前記外径面側及び前記端面側でそれぞれ両方向に１．０ｍｍ以上のＲ形状となるように加工されていることを特徴とする請求項１に記載した車輪支持用軸受装置。   The edge portion between the outer diameter surface of the inner ring and the crimping portion side end surface is processed so as to have an R shape of 1.0 mm or more in both directions on the outer diameter surface side and the end surface side, respectively. The wheel support bearing device according to claim 1.
JP2003330125A 2003-09-22 2003-09-22 Bearing apparatus for supporting wheel Pending JP2005098320A (en)

Priority Applications (1)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007024148A (en) * 2005-07-14 2007-02-01 Ntn Corp Wheel bearing device
JP2007239965A (en) * 2006-03-13 2007-09-20 Ntn Corp Bearing device for wheel
JP2013155842A (en) * 2012-01-31 2013-08-15 Jtekt Corp Mounting structure of inner ring of bearing, and bearing device for wheel
JP2015030871A (en) * 2013-08-01 2015-02-16 日本電信電話株式会社 Steel material processing method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007024148A (en) * 2005-07-14 2007-02-01 Ntn Corp Wheel bearing device
JP4632305B2 (en) * 2005-07-14 2011-02-16 Ｎｔｎ株式会社 Wheel bearing device
JP2007239965A (en) * 2006-03-13 2007-09-20 Ntn Corp Bearing device for wheel
JP2013155842A (en) * 2012-01-31 2013-08-15 Jtekt Corp Mounting structure of inner ring of bearing, and bearing device for wheel
JP2015030871A (en) * 2013-08-01 2015-02-16 日本電信電話株式会社 Steel material processing method

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