JP2013113370A - Support shaft for rotary member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a support member 4a which can reduce material cost and can shorted a working time while securing durability.SOLUTION: The support shaft 4a is formed of alloyed steel which contains 0.50-0.58 mass% of C, 0.1-0.4 mass% of Si, 0.5-1.0 mass% of Mn and 0.1-0.4 mass% of Cr and has an oxygen content of 15 ppm or smaller. Furthermore, over a range in both axial-direction sides wider than a plurality of rows of inner ring raceways 11 and in a portion of the support shaft 4a excluding both axial-direction ends, a hardened layer 22 is formed over the full circumference by induction hardening. Moreover, the hardened layer 22 is formed over the range from an outer circumferential surface of the support shaft 4a to an axial center.

Description

本発明は、自動車、一般産業機械、工作機械等に組み込まれる回転部材を、ラジアルニードル軸受を介して回転自在に支持する為の回転部材用支持軸の改良に関する。   The present invention relates to an improvement of a support shaft for a rotary member for rotatably supporting a rotary member incorporated in an automobile, a general industrial machine, a machine tool, or the like via a radial needle bearing.

自動車用自動変速機を構成する遊星歯車装置が従来から、例えば特許文献１、２等、多くの刊行物に記載されて、広く知られている。この従来から知られた遊星歯車装置は、例えば図５〜６に示す様に、外周面に歯１ａを形成した太陽歯車１と、この太陽歯車１と同心に配置され、内周面に歯２ａを形成したリング歯車２との間に、複数個（一般的には３〜４個）の遊星歯車３、３を、円周方向に関して等間隔に配置している。そして、これら複数個の遊星歯車３、３の外周面に形成した歯３ａを、前記両歯１ａ、２ａに噛合させている。   2. Description of the Related Art Conventionally, planetary gear devices constituting an automatic transmission for automobiles have been widely known as described in many publications such as Patent Documents 1 and 2, for example. As shown in FIGS. 5 to 6, for example, this conventionally known planetary gear device includes a sun gear 1 having teeth 1 a formed on the outer peripheral surface thereof, a concentric arrangement with the sun gear 1, and teeth 2 a on the inner peripheral surface thereof. A plurality (generally 3 to 4) of planetary gears 3 and 3 are arranged at equal intervals in the circumferential direction between the ring gear 2 and the ring gear 2. The teeth 3a formed on the outer peripheral surfaces of the plurality of planetary gears 3 and 3 are meshed with the teeth 1a and 2a.

前記複数個の遊星歯車３、３は、それぞれ支持軸４、４の周囲に、それぞれ複数本のニードル５、５を介して、回転自在に支持されている。これら各支持軸４の軸方向両端部のうち、一方の端部（図６の右端部）は、前記太陽歯車１を中心として回転自在なキャリア６に対し、他方の端部（図６の左端部）は、円輪状に形成された連結板７に対し、それぞれ支持固定している。この為に、前記キャリア６及び前記連結板７のうちの互いに整合する部分に１対の通孔８ａ、８ｂを形成している。そして、前記支持軸４の軸方向両端部を、これら各通孔８ａ、８ｂに内嵌した状態で、この支持軸４の軸方向両端部外周縁部を径方向外方にかしめ拡げ、当該部分にかしめ部９、９を形成する。これにより、前記支持軸４を、前記キャリア６と前記連結板７との間に掛け渡す状態で支持固定している。   The plurality of planetary gears 3 and 3 are rotatably supported around the support shafts 4 and 4 via a plurality of needles 5 and 5, respectively. Of the both ends in the axial direction of each of the support shafts 4, one end (the right end in FIG. 6) is the other end (the left end in FIG. 6) with respect to the carrier 6 that is rotatable around the sun gear 1. Are supported and fixed to the connecting plate 7 formed in an annular shape. For this purpose, a pair of through-holes 8a and 8b are formed in portions of the carrier 6 and the connecting plate 7 that are aligned with each other. Then, with both axial ends of the support shaft 4 fitted in the through holes 8a and 8b, the outer peripheral edges of the axial ends of the support shaft 4 are squeezed radially outward, and the portions The caulking portions 9 and 9 are formed. Thereby, the support shaft 4 is supported and fixed in a state of being spanned between the carrier 6 and the connecting plate 7.

又、前記支持軸４の中間部外周面で、前記キャリア６と前記連結板７との間部分には、複列の内輪軌道１０、１０を形成している。一方、前記遊星歯車３の内周面には、複列の外輪軌道１１、１１を形成している。そして、これら内輪軌道１０、１０と外輪軌道１１、１１との間部分に、それぞれ前記各ニードル５、５から成る複列のラジアルニードル軸受１２を設けて、前記遊星歯車３を、前記支持軸４の中間部周囲で、前記キャリア６と前記連結板７との間部分に、回転自在に支持している。   Double row inner ring raceways 10 and 10 are formed on the outer peripheral surface of the intermediate portion of the support shaft 4 between the carrier 6 and the connecting plate 7. On the other hand, double-row outer ring raceways 11 and 11 are formed on the inner peripheral surface of the planetary gear 3. A double-row radial needle bearing 12 comprising the needles 5 and 5 is provided between the inner ring raceways 10 and 10 and the outer ring raceways 11 and 11, respectively. Around the intermediate portion of the carrier 6 and rotatably supported by the portion between the carrier 6 and the connecting plate 7.

又、図示の例では、前記太陽歯車１を円筒状に形成し、前記キャリア６を、断面Ｌ字形で全体を円輪状に形成している。そして、図６に示す様に、このキャリア６の内周縁部に形成した円筒部１３を、回転軸１４の外周面にスプライン係合させている。前記太陽歯車１は、この回転軸１４の周囲に、この回転軸１４に対する相対回転を自在に支持している。又、前記リング歯車２は、前記各部材１、６、１４の周囲に、これら各部材１、６、１４に対する相対回転自在に支持している。   In the illustrated example, the sun gear 1 is formed in a cylindrical shape, and the carrier 6 is formed in an annular shape with an L-shaped cross section. As shown in FIG. 6, the cylindrical portion 13 formed on the inner peripheral edge of the carrier 6 is spline-engaged with the outer peripheral surface of the rotating shaft 14. The sun gear 1 freely supports relative rotation with respect to the rotating shaft 14 around the rotating shaft 14. The ring gear 2 is supported around the members 1, 6 and 14 so as to be rotatable relative to the members 1, 6 and 14.

上述の様な遊星歯車３及び支持軸４等を含んで構成する遊星歯車装置は、例えば、前記回転軸１４を駆動軸又は従動軸とし、前記太陽歯車１又は前記リング歯車２の中心を従動軸又は駆動軸に結合する。そして、何れの歯車１、２、３を回転自在とし、何れの歯車１、２、３を回転不能とするかを切り換える事により、前記駆動軸と従動軸との間の変速並びに回転方向の変換を行う。この様な遊星歯車装置自体の構成及び作用は、従来から周知であり、本発明の要旨とも関係しないから、全体構造の図示並びに詳しい説明は省略する。   In the planetary gear device configured to include the planetary gear 3 and the support shaft 4 as described above, for example, the rotary shaft 14 is a drive shaft or a driven shaft, and the center of the sun gear 1 or the ring gear 2 is a driven shaft. Or it couple | bonds with a drive shaft. Then, by switching which gears 1, 2, and 3 are rotatable and which gears 1, 2, and 3 are non-rotatable, the shift between the drive shaft and the driven shaft and the conversion of the rotation direction are switched. I do. Since the configuration and operation of such a planetary gear device itself are conventionally well known and are not related to the gist of the present invention, illustration and detailed description of the entire structure are omitted.

ところで、近年、自動車用自動変速機の使用条件が厳しくなるに従って、遊星歯車装置に組み込む支持軸に対し、耐久性に関する要求が高まっている。この為、支持軸を、ＳＵＪ２等の高炭素クロム軸受鋼｛ＪＩＳ Ｇ ４８０５、Ｃ（炭素）の含有量：０．９５〜１．１０質量％｝を初めとする高炭素鋼｛本明細書中で「高炭素鋼」とは、Ｃの含有量が０．６質量％以上の炭素鋼を言い、同じく「中炭素鋼」とは、Ｃの含有量が０．６質量％未満（且つ０．２５質量％より高い）の炭素鋼を言う。｝から造る事が考えられている。又、この様な高炭素鋼製の支持軸に、浸炭窒化処理や高周波焼き入れ処理を施す事も、例えば特許文献３等に記載され、従来から知られている。この様に、高炭素鋼の様な高炭素濃度の材料から支持軸を造れば、この支持軸の硬度として高い値が得られ易くなる。又、浸炭窒化処理や高周波焼き入れ処理を施せば、軌道面となる部分にのみ硬化層を形成する事ができて、その他の部分（軸方向両端部）には硬化層を形成せずに済む。この為、軌道面の転がり疲れ寿命を向上させて、耐久性を向上できると共に、かしめによる固定手段を採用する事も可能になる。   By the way, in recent years, as the conditions for use of an automatic transmission for automobiles become severe, demands regarding durability have been increasing for support shafts incorporated in planetary gear devices. For this reason, the support shaft is made of high carbon steel such as SUJ2 or other high carbon chrome bearing steel {JIS G 4805, C (carbon) content: 0.95 to 1.10% by mass} {in this specification The “high carbon steel” means a carbon steel having a C content of 0.6% by mass or more, and similarly, the “medium carbon steel” has a C content of less than 0.6% by mass (and less than 0.1% by mass). Carbon steel of higher than 25% by mass). } Is considered to be made from. In addition, it has been conventionally known that carbonitriding or induction hardening is performed on such a support shaft made of high carbon steel, for example, in Patent Document 3. As described above, if the support shaft is made of a material having a high carbon concentration such as high carbon steel, a high value can be easily obtained as the hardness of the support shaft. Further, if carbonitriding or induction hardening is performed, a hardened layer can be formed only on the portion that becomes the raceway surface, and it is not necessary to form a hardened layer on the other portions (both ends in the axial direction). . For this reason, the rolling fatigue life of the raceway surface can be improved, durability can be improved, and fixing means by caulking can be employed.

但し、支持軸を造る為の材料として高炭素鋼を使用した場合、材料コストが嵩むと共に、加工時間が長くなると言った問題を招く。即ち、高炭素クロム軸受鋼の様な高炭素鋼は、例えばＳ５３Ｃ等の中炭素鋼に比べて、高価である為、支持軸の材料コストが嵩む事が避けられない。又、高炭素クロム軸受鋼の様な高炭素鋼から支持軸を造る場合、高周波焼き入れ処理等の有無に拘わらず、元々の（生の状態での）硬度が高い為、かしめ部を形成する為の軸方向両端部分の加工時間が長くなる。具体的には、図７に示した様に、支持軸４の軸方向両端部には、かしめ部９、９（図６参照）を形成する為のかしめ用筒部１５、１５を形成する必要があり、これら各かしめ用筒部１５、１５を形成するには、支持軸４の軸方向両端面１６、１６の中央に、円すい台形状の凹部１７、１７を形成する必要がある。但し、高炭素クロム軸受鋼の様な硬質材料を用いた場合、鍛造加工により凹部１７、１７を加工する事は困難である。この為、円すい台形状の凹部１７、１７を切削加工により加工する必要があるが、この様な切削加工を硬質材料に対して行う場合には、加工時間が特に長くなる。更に、この様にして形成したかしめ用筒部１５、１５を、径方向外方に塑性変形させる為の加工時間も長くなる。   However, when high carbon steel is used as a material for forming the support shaft, the material cost increases and the processing time is increased. That is, high carbon steel such as high carbon chrome bearing steel is more expensive than medium carbon steel such as S53C, and thus the material cost of the support shaft is inevitably increased. In addition, when the support shaft is made from high carbon steel such as high carbon chrome bearing steel, the caulking portion is formed because the original (raw) hardness is high regardless of whether or not induction hardening is performed. For this reason, the machining time at both ends in the axial direction becomes longer. Specifically, as shown in FIG. 7, it is necessary to form caulking cylinder portions 15, 15 for forming caulking portions 9, 9 (see FIG. 6) at both ends in the axial direction of the support shaft 4. In order to form these caulking tube portions 15, 15, it is necessary to form conical recesses 17, 17 at the centers of the axial end surfaces 16, 16 of the support shaft 4. However, when a hard material such as high carbon chromium bearing steel is used, it is difficult to process the recesses 17 and 17 by forging. For this reason, it is necessary to process the conical recesses 17 and 17 by cutting. However, when such cutting is performed on a hard material, the processing time is particularly long. Furthermore, the processing time for plastically deforming the caulking tube portions 15 and 15 formed in this manner radially outward is also increased.

特開平１１−２７０６６１号公報JP 11-270661 A 特開２００２−２３５８４１号公報JP 2002-235841 A 特開２００７−２１７７２５号公報JP 2007-217725 A

本発明は、上述の様な事情に鑑みて、耐久性を確保できるだけでなく、材料コストの低減を図れ、しかも加工時間を短縮できる、回転部材用支持軸を実現すべく発明したものである。   In view of the circumstances as described above, the present invention has been invented to realize a support shaft for a rotating member that not only can ensure durability, but also can reduce material costs and shorten processing time.

本発明の回転部材用支持軸は、例えばキャリア、ロッカーアーム、バルブリフタ、タペット等を構成する、互いに離隔して設けられた１対の支持壁部（キャリアと連結板の様に互いに別部材である場合も含む）の互いに整合する位置に形成された１対の通孔に、その軸方向両端部を内嵌した状態で、この軸方向両端部の外周縁部分を径方向外方にかしめ拡げる事で、前記１対の支持壁部同士の間に掛け渡された状態で支持固定される。
又、軸方向中間部周囲に、例えば遊星歯車、カムフォロア、ローラ、カムローラ等の回転部材を、ラジアルニードル軸受（転動体としてころを使用する構造、並びに、転動体が複列に配置された構造を含む）を介して、回転自在に支持する。 The support shaft for a rotating member of the present invention is a pair of support wall portions (separate members such as a carrier and a connecting plate) provided apart from each other, for example, constituting a carrier, a rocker arm, a valve lifter, a tappet and the like. The outer peripheral edge portions of both axial end portions are caulked outward in the radial direction in a state in which both axial end portions are fitted in a pair of through holes formed at positions aligned with each other. Thus, it is supported and fixed in a state of being spanned between the pair of support wall portions.
In addition, a rotating member such as a planetary gear, a cam follower, a roller, a cam roller, or the like is provided around the intermediate portion in the axial direction, a radial needle bearing (a structure that uses rollers as rolling elements, and a structure in which the rolling elements are arranged in double rows. Support) through a support.

特に本発明にあっては、前記回転部材用支持軸を、Ｃ（炭素）を０．５０〜０．５８質量％、Ｓｉ（ケイ素）を０．１〜０．４質量％、Ｍｎ（マンガン）を０．５〜１．０質量％、Ｃｒ（クロム）を０．１〜０．４質量％含有する合金鋼製としている。尚、合金鋼の残部は、Ｆｅと、Ｏと、ＳやＰ等の不可避不純物である。
又、外周面のうちで、前記ラジアルニードル軸受を構成する各ニードルの転動面が転がり接触する軌道面（単列、複列を問わない）を含み、この軌道面よりも軸方向両側に広い範囲で、且つ、軸方向両端部を除く部分に、高周波焼き入れ処理による硬化層（表面硬さがビッカース硬度で６３３Ｈｖ以上の硬化層）を全周に亙り形成している。 Particularly in the present invention, the support shaft for the rotating member is composed of C (carbon) of 0.50 to 0.58 mass%, Si (silicon) of 0.1 to 0.4 mass%, and Mn (manganese). Is made of an alloy steel containing 0.5 to 1.0 mass% and Cr (chromium) 0.1 to 0.4 mass%. The balance of the alloy steel is inevitable impurities such as Fe, O, S and P.
In addition, the outer peripheral surface includes a raceway surface (whether single row or double row) in which the rolling surface of each needle constituting the radial needle bearing is in rolling contact, and is wider on both sides in the axial direction than the raceway surface. A hardened layer (a hardened layer having a surface hardness of 633 Hv or more in terms of Vickers hardness) is formed over the entire circumference in a range and in a portion excluding both ends in the axial direction.

上述した様な本発明を実施する場合に好ましくは、例えば請求項２に記載した発明の様に、前記合金鋼中の酸素量（酸素濃度）を、１５ｐｐｍ以下（より好ましくは１２ｐｐｍ以下）とする。   Preferably, when the present invention as described above is carried out, for example, as in the invention described in claim 2, the amount of oxygen (oxygen concentration) in the alloy steel is set to 15 ppm or less (more preferably 12 ppm or less). .

又、本発明を実施する場合に好ましくは、例えば請求項３に記載した発明の様に、前記硬化層を、前記回転部材用支持軸の外周面から軸心部（中心部）に至る範囲に形成する。言い換えれば、軸心部にも、非硬化部（生のままの部分）を設けない様にする。
尚、本発明を実施する場合に、回転部材用支持軸の内部に通油孔を設ける事もできるが、この様な場合には、回転部材用支持軸の外周面から通油孔に至る範囲に硬化層を形成する。 Further, when the present invention is carried out, preferably, as in the invention described in claim 3, for example, the hardened layer is in a range from the outer peripheral surface of the rotating member support shaft to the shaft center portion (center portion). Form. In other words, no non-hardened part (raw part) is provided in the axial part.
In the case of carrying out the present invention, an oil passage hole can be provided inside the rotating member support shaft. In such a case, the range from the outer peripheral surface of the rotating member support shaft to the oil passage hole is provided. A hardened layer is formed.

以上の様な構成を有する本発明の回転部材用支持軸によれば、耐久性を確保できるだけでなく、材料コストの低減を図れ、しかも加工時間を短縮できる。
即ち、本発明の場合には、回転部材用支持軸を造る為の材料として、Ｃ（炭素）の含有量が０．５０〜０．５８質量％である合金鋼（中炭素鋼）を使用する為、高炭素クロム軸受鋼の様な高炭素鋼を用いた場合に比べて、材料コストの低減を図れる。
又、本発明の場合、回転部材用支持軸を造る為の材料は、Ｃの含有量が低く、元々の（生の状態での）硬度が低い事に加え、軸方向両端部には高周波焼き入れ処理後も硬化層を形成しない為、かしめ部を形成する為の加工時間を短縮する事が可能になる。
具体的には、高周波焼き入れ処理を施す以前の状態で、素材全体の硬度を低く抑えられる為、軸方向両端面に、円すい台形状の凹部を、鍛造加工により形成する事が可能になり、加工時間の大幅な短縮化を図れるか、或いは、切削加工により形成する場合にも、高炭素クロム軸受鋼の様な硬質材料を用いた場合に比べて、加工時間を短縮できる。更に、この様な円すい台形状の凹部を形成する事に伴って、その周囲に形成されたかしめ用筒部は、高周波焼き入れ処理によっても硬化させない為、このかしめ用筒部を径方向外方に塑性変形させる際の加工時間も短縮できる。加えて、かしめ部に割れや亀裂等の損傷が生じる事も有効に防止する事もできる。
又、Ｃの含有量及びＳｉの含有量を、軌道面に必要となる硬さを確保できる様に適正に規制した上で、高周波焼き入れによる硬化層を形成している為、軌道面部分の表面硬さを、転がり疲れ寿命を確保するのに必要な硬さに規制できる。又、軌道面部分に、疲労強度の向上に有利となる残留圧縮応力を発生させる事もできる。従って、転がり疲れ寿命を確保できて、十分な耐久性を確保できる。
更に、本発明の場合には、Ｃ以外の成分（Ｓｉ、Ｍｎ、Ｃｒ）に関しても、それぞれの含有量を適正に規制している為、品質のばらつきを抑える事ができる。 According to the support shaft for a rotating member of the present invention having the above-described configuration, not only the durability can be ensured, but also the material cost can be reduced and the processing time can be shortened.
That is, in the case of the present invention, an alloy steel (medium carbon steel) having a C (carbon) content of 0.50 to 0.58 mass% is used as a material for producing a support shaft for a rotating member. Therefore, the material cost can be reduced as compared with the case where high carbon steel such as high carbon chromium bearing steel is used.
In addition, in the case of the present invention, the material for making the support shaft for the rotating member has a low C content and low hardness (in the raw state). Since a hardened layer is not formed after the insertion process, it is possible to shorten the processing time for forming the caulking portion.
Specifically, since the hardness of the entire material can be kept low before the induction hardening process is performed, it becomes possible to form conical recesses on both end faces in the axial direction by forging, The machining time can be significantly shortened, or the machining time can be shortened compared with the case of using a hard material such as high carbon chrome bearing steel even when formed by cutting. Furthermore, the caulking tube portion formed around the conical concave portion is not hardened by the induction hardening process, so that the caulking tube portion is radially outward. The processing time for plastic deformation can be shortened. In addition, it is possible to effectively prevent the caulking portion from being damaged such as a crack or a crack.
In addition, the content of C and the content of Si are appropriately regulated so as to ensure the hardness required for the raceway surface, and since a hardened layer is formed by induction hardening, The surface hardness can be regulated to a hardness necessary to ensure a rolling fatigue life. Further, residual compressive stress that is advantageous for improving the fatigue strength can be generated in the raceway surface portion. Therefore, a rolling fatigue life can be secured and sufficient durability can be secured.
Furthermore, in the case of the present invention, since the respective contents of components other than C (Si, Mn, Cr) are appropriately regulated, variation in quality can be suppressed.

又、請求項２に記載した発明によれば、軌道面に、剥離の起点となる酸化物系の介在物が形成されにくくなる為、転がり疲れ寿命の更なる向上を図れる。   According to the second aspect of the present invention, it is difficult to form oxide-based inclusions as starting points of separation on the raceway surface, so that the rolling fatigue life can be further improved.

更に、請求項３に記載した発明によれば、回転部材用支持軸の強度（主として曲げ強度）を十分に向上させる事が可能になる。   Furthermore, according to the invention described in claim 3, it is possible to sufficiently improve the strength (mainly bending strength) of the support shaft for the rotating member.

以下、前記回転部材用支持軸の材料である合金鋼（鋼材）の組成に就いて、含有量を上述した範囲に規制する理由と共に説明する。
［Ｃを０．５０〜０．５８質量％］
Ｃ（炭素）は、回転部材用支持軸に、転がり軸受（軌道輪である内輪）として要求される硬さを付与する作用を有する。前記合金鋼中のＣの含有量が０．５０質量％未満であると、転がり軸受として要求される硬さ（軌道面の表面硬さ）の目安となる、ビッカース硬度で６３３Ｈｖ（ロックウェル硬度５７ＨＲＣ）以上を確保できなくなる可能性がある。一方、Ｃの含有量が０．５８％を超えると、かしめ部を形成する際に亀裂や割れ等の損傷が生じたり、鍛造性や切削性を低下させる。そこで、前記合金鋼のＣの含有量を、０．５０〜０．５８質量％の範囲に規制した。
尚、軌道面の表面硬さは、各ニードルから繰り返し加わる剪断応力に耐え、転がり疲れ寿命を向上させる面からは、ビッカース硬度で６６０Ｈｖ以上とする事が好ましい。 Hereinafter, the composition of alloy steel (steel material) that is a material of the support shaft for the rotating member will be described together with the reason for restricting the content to the above-described range.
[C 0.50 to 0.58 mass%]
C (carbon) has the effect | action which provides the hardness requested | required as a rolling bearing (inner ring which is a bearing ring) to the support shaft for rotating members. When the content of C in the alloy steel is less than 0.50% by mass, the Vickers hardness is 633 Hv (Rockwell hardness 57 HRC), which is a measure of the hardness required for the rolling bearing (surface hardness of the raceway surface). ) There is a possibility that the above cannot be secured. On the other hand, when the content of C exceeds 0.58%, damage such as cracks or cracks occurs when the caulking portion is formed, and forgeability and machinability are reduced. Therefore, the C content of the alloy steel is regulated to a range of 0.50 to 0.58 mass%.
The surface hardness of the raceway surface is preferably set to 660 Hv or more in terms of Vickers hardness from the viewpoint of withstanding the shear stress repeatedly applied from each needle and improving the rolling fatigue life.

［Ｓｉを０．１〜０．４質量％］
Ｓｉ（ケイ素）は、焼き入れによる表面（軌道面）硬さを向上させると共に、軌道面の転がり疲れ寿命を向上させ、併せて、合金鋼中の酸素量を低下させる（脱酸効果を有する）。即ち、Ｓｉは、基地に固溶して、焼き入れ性を向上させると共に、焼き戻し軟化抵抗性を向上させて、軌道面に必要な硬さを与える。又、基地組織を強化し、この軌道面の転がり疲れ寿命を向上させる。又、合金鋼中の酸素と反応して酸化物を生成し、この合金鋼中の酸素量を低下させる。但し、Ｓｉの含有量が０．１質量％未満の場合には、脱酸効果が十分には得られない。これに対して、Ｓｉの含有量が０．４質量％を超えると、かしめ部を形成する際のかしめ性が低下したり、切削性を著しく低下させると共に、Ｓｉの溶け込みが不足し、巨大なＳｉＣが析出して十分な表面硬さが得られなくなる。そこで、前記合金鋼のＳｉの含有量を、０．１〜０．４質量％の範囲に規制した。尚、合金鋼のＳｉの含有量は、好ましくは０．１３〜０．３７質量％とする。 [Si 0.1-0.4% by mass]
Si (silicon) improves the surface (orbital surface) hardness by quenching, improves the rolling fatigue life of the raceway surface, and also reduces the oxygen content in the alloy steel (has a deoxidizing effect). . That is, Si dissolves in the base to improve the hardenability and improve the temper softening resistance to give the raceway the necessary hardness. It also strengthens the base structure and improves the rolling fatigue life of this raceway surface. Moreover, it reacts with oxygen in the alloy steel to produce an oxide, thereby reducing the amount of oxygen in the alloy steel. However, when the Si content is less than 0.1% by mass, the deoxidation effect cannot be sufficiently obtained. On the other hand, when the content of Si exceeds 0.4% by mass, the caulking property at the time of forming the caulking portion is reduced, the machinability is remarkably lowered, and the penetration of Si is insufficient. SiC is precipitated and sufficient surface hardness cannot be obtained. Therefore, the Si content of the alloy steel is regulated to a range of 0.1 to 0.4 mass%. The Si content of the alloy steel is preferably 0.13 to 0.37% by mass.

［Ｍｎを０．５〜１．０質量％］
Ｍｎ（マンガン）は、基地に固溶して、焼き入れ性を向上させる。但し、前記合金鋼中のＭｎの含有量が０．５質量％未満では、焼き入れ性（高周波焼き入れ性）が不足してしまい、反対に、１．０質量％を超えて含有すると、鋼中の不純物であるＳ（硫黄）やＰ（燐）と非金属介在物を形成し易くなり、強度を低下させる可能性がある。そこで、前記合金鋼のＭｎの含有量を、０．５〜１．０質量％の範囲に規制した。尚、合金鋼のＭｎの含有量は、好ましくは０．６５〜０．９５質量％とする。 [Mn 0.5 to 1.0 mass%]
Mn (manganese) dissolves in the matrix and improves hardenability. However, if the Mn content in the alloy steel is less than 0.5% by mass, the hardenability (high frequency hardenability) is insufficient, and conversely if it exceeds 1.0% by mass, the steel It becomes easy to form non-metallic inclusions with S (sulfur) and P (phosphorus) which are impurities therein, and the strength may be lowered. Therefore, the Mn content of the alloy steel is regulated to a range of 0.5 to 1.0% by mass. The Mn content in the alloy steel is preferably 0.65 to 0.95 mass%.

［Ｃｒを０．１〜０．４質量％］
Ｃｒ（クロム）は、基地に固溶して、焼き入れ性、耐食性等を向上させると共に、Ｃと結合して鋼中に硬い炭化物を形成し（炭化物球状化を促進させ）、耐摩耗性を向上させる元素である。但し、前記合金鋼中のＣｒの含有量が０．１質量％未満の場合には、前記の効果を十分には得られない。これに対して、このＣｒの添加量が０．４質量％を超えると、炭化物が粗大化して平均結晶粒が大きくなる。この為、加工性を低下させる場合があると共に、コストが嵩む原因になる。そこで、前記合金鋼中のＣｒの含有量を、０．１〜０．４質量％の範囲に規制した。尚、合金鋼のＣｒの含有量は、好ましくは０．１〜０．２５質量％とする。 [Cr 0.1-0.4 mass%]
Cr (Chromium) dissolves in the base and improves hardenability, corrosion resistance, etc., and combines with C to form hard carbides in the steel (accelerate carbide spheroidization) and improve wear resistance. It is an element to improve. However, when the content of Cr in the alloy steel is less than 0.1% by mass, the above effect cannot be obtained sufficiently. On the other hand, when the added amount of Cr exceeds 0.4% by mass, the carbide is coarsened and the average crystal grain is increased. For this reason, while workability may be reduced, it causes cost increase. Therefore, the content of Cr in the alloy steel is regulated to a range of 0.1 to 0.4% by mass. The Cr content in the alloy steel is preferably 0.1 to 0.25% by mass.

［酸素量（酸素濃度）を１５ｐｐｍ以下とした理由］
合金鋼中の酸素量が高くなると、焼き入れされた軌道面に剥離の起点となる酸化物系の介在部が形成される為、転がり疲れ寿命が低下する。この為、転がり疲れ寿命の向上を図る為に、前記合金鋼中の酸素量を低くする事が好ましい。そこで、この酸素量の上限値を１５ｐｐｍとした。耐久性の更なる向上を図る面からは、酸素量の上限値は１２ｐｐｍとする事が望ましい。 [Reason for setting oxygen amount (oxygen concentration) to 15 ppm or less]
When the amount of oxygen in the alloy steel becomes high, an oxide-based intervening portion that becomes a starting point of peeling is formed on the hardened raceway surface, so that the rolling fatigue life is lowered. For this reason, in order to improve the rolling fatigue life, it is preferable to reduce the amount of oxygen in the alloy steel. Therefore, the upper limit value of the oxygen amount is set to 15 ppm. From the viewpoint of further improving the durability, the upper limit value of the oxygen amount is desirably 12 ppm.

［Ｐ、Ｓの好ましい含有量］
Ｐ（燐）は、不可避的に鋼中に混入する有害不純物元素であり、転がり疲れ寿命及び靱性を低下させる元素である為、含有量は少ない程好ましいが、含有量を０とする事は、コストを抑える面から非現実的である。但し、含有量が０．０３質量％を超えると、強度低下等の不利益が無視できなくなる。そこで、Ｐの含有量の上限値は、好ましくは０．０３質量％以下とする。
Ｓ（硫黄）は、被削性を向上させる元素であるが、Ｍｎと結合して、非金属介在物であるＭｎＳとなり、割れの起点になり易くなったり、或いは、Ｔｉ（チタン）と結合して、転がり疲れ寿命を低下させる硫化系介在物を形成する。この為、Ｓの含有量の上限値は、好ましくは０．０３質量％以下とする。 [Preferable content of P and S]
P (phosphorus) is a harmful impurity element inevitably mixed in the steel, and is an element that lowers the rolling fatigue life and toughness. Therefore, the smaller the content, the more preferable. It is unrealistic in terms of cost reduction. However, when the content exceeds 0.03% by mass, disadvantages such as strength reduction cannot be ignored. Therefore, the upper limit value of the P content is preferably 0.03% by mass or less.
S (sulfur) is an element that improves machinability. However, it combines with Mn to become MnS, which is a non-metallic inclusion, and easily becomes a starting point of cracking, or combines with Ti (titanium). Thus, sulfide inclusions that reduce the rolling fatigue life are formed. For this reason, the upper limit of the S content is preferably 0.03% by mass or less.

本発明の対象となる回転部材用支持軸を組み込んだ遊星歯車装置を、この回転部材用支持軸の軸方向両端部にかしめ部を形成する以前の状態で示す断面図。Sectional drawing which shows the planetary gear apparatus incorporating the support shaft for rotation members used as the object of this invention in the state before forming a crimp part in the axial direction both ends of this support shaft for rotation members. かしめ部を形成した以後の状態を示す、図１のＡ部に相当する拡大断面図。The expanded sectional view equivalent to the A section of Drawing 1 showing the state after forming a caulking part. 軸方向両端面の凹部を省略した状態で示す、回転部材用支持軸の略断面図。The schematic sectional drawing of the support shaft for rotation members shown in the state which abbreviate | omitted the recessed part of the axial direction both end surfaces. 本発明の効果を確認する為に行った耐久寿命試験の実施状況を示す模式図。The schematic diagram which shows the implementation condition of the durable life test done in order to confirm the effect of this invention. 従来構造の遊星歯車装置の１例を示す略側面図。The schematic side view which shows an example of the planetary gear apparatus of a conventional structure. 図５のＢ−Ｂ断面図。BB sectional drawing of FIG. 同じく支持軸のみを取り出して示す断面図。Sectional drawing which takes out and shows only a support shaft similarly.

図１〜３は、本発明の実施の形態の１例を示している。本発明の特徴は、例えば遊星歯車をキャリアに対して、ラジアルニードル軸受を介して回転自在に支持する為に使用する回転部材用支持軸に関して、材料となる合金鋼の組成、並びに、高周波焼き入れ処理により形成する硬化層の範囲等を工夫する事で、耐久性を確保しつつ、材料コストの低減を図ると共に、加工時間の短縮化を図った点にある。図面に表れる構造に就いては、硬化層の形成範囲を除いて、従来から知られている支持軸と基本的には同じである為、共通する部分の説明は省略する。   1 to 3 show an example of an embodiment of the present invention. The features of the present invention include, for example, the composition of alloy steel as a material and induction hardening for a support shaft for a rotating member used to rotatably support a planetary gear with respect to a carrier via a radial needle bearing. By devising the range of the hardened layer formed by the treatment, the material cost is reduced and the processing time is shortened while ensuring the durability. The structure shown in the drawing is basically the same as a conventionally known support shaft except for the formation range of the hardened layer, and thus description of common parts is omitted.

支持軸４ａの周囲に、ラジアルニードル軸受１２を介して、遊星歯車３を回転自在に支持する為に、この支持軸４ａを、キャリア６ａを構成する１対の支持壁部１８、１８同士の間に掛け渡す状態で支持固定している。この為に、前記支持軸４ａの軸方向両端面１６ａ、１６ａの中央に、円すい台形状の凹部１７ａ、１７ａを形成し、その周囲（支持軸４ａの軸方向両端部外周縁部）に、かしめ用筒部１５ａ、１５ａを形成している。一方、前記各支持壁部１８、１８には、互いに整合する位置に１対の通孔８ｃ、８ｃを形成しており、これら各支持壁部１８、１８の外側面のうちで、これら各通孔８ｃ、８ｃの開口縁部には、外側面側に向かう程内径寸法が大きくなる方向に傾斜した面取り部１９、１９を形成している。   In order to rotatably support the planetary gear 3 around the support shaft 4a via the radial needle bearing 12, the support shaft 4a is provided between a pair of support wall portions 18 and 18 constituting the carrier 6a. It is supported and fixed in a state where it is passed over. For this purpose, conical recesses 17a and 17a are formed in the center of the axial end surfaces 16a and 16a of the support shaft 4a, and caulked around the periphery (outer peripheral edges of the axial ends of the support shaft 4a). Tube portions 15a, 15a are formed. On the other hand, a pair of through-holes 8c, 8c are formed in the support wall portions 18, 18 at positions aligned with each other. Chamfered portions 19 and 19 are formed at the opening edge portions of the holes 8c and 8c. The chamfered portions 19 and 19 are inclined in a direction in which the inner diameter dimension increases toward the outer surface side.

そして、図２に示した様に、前記各かしめ用筒部１５ａを、径方向外方にかしめ拡げ（塑性変形させて）、これら各かしめ用筒部１５ａの外周面を前記各面取り部１９の内周面に向けて押し付ける事で、当該部分にかしめ部９を形成する。これにより、前記支持軸４ａを、前記キャリア６ａを構成する１対の支持壁部１８、１８同士の間に掛け渡す状態で支持固定する。   Then, as shown in FIG. 2, the caulking cylinder portions 15 a are caulked and expanded (plastically deformed) radially outward, and the outer peripheral surfaces of the caulking cylinder portions 15 a are formed on the chamfered portions 19. By pressing toward the inner peripheral surface, the caulking portion 9 is formed in the portion. Thus, the support shaft 4a is supported and fixed in a state of being spanned between a pair of support wall portions 18 and 18 constituting the carrier 6a.

又、本例の場合、これら各支持壁部１８、１８のうち、互いに対向する内側面２３、２３が、各ニードル５、５や、前記遊星歯車３の軸方向端面との擦れ合いにより摩耗するのを防止する為に、前記支持軸４ａの周囲で、前記各支持壁部１８、１８の内側面２３、２３と前記遊星歯車３の軸方向端面との間部分に、円輪状のワッシャ２０、２０を設けている。又、複列に配置された前記各ニードル５、５のスキュー防止を図る為、両列のニードル５、５同士の間に、円環状のスペーサ２１を配置し、これら各ニードル５、５の軸方向端面を案内する様にしている。この様なスペーサ２１としては、鋼製或いは合成樹脂製で、削り出し加工や打ち抜き成型（プレス加工）等により形成されたもの使用できる。   In the case of this example, of these support wall portions 18, 18, the inner side surfaces 23, 23 facing each other are worn by rubbing with the needles 5, 5 and the axial end surface of the planetary gear 3. In order to prevent this, an annular washer 20 is provided around the support shaft 4a between the inner side surfaces 23, 23 of the support wall portions 18, 18 and the end surface in the axial direction of the planetary gear 3. 20 is provided. Further, in order to prevent skew of the needles 5 and 5 arranged in a double row, an annular spacer 21 is arranged between the needles 5 and 5 in both rows, and the shafts of the needles 5 and 5 are arranged. The direction end face is guided. As such a spacer 21, it is possible to use one made of steel or synthetic resin and formed by machining or punching (pressing).

上述の様にして前記キャリア６ａに支持固定される本例の支持軸４ａは、従来構造の様に高炭素鋼を材料とするものではなく、中炭素鋼であるＳ５３Ｃ（ＪＩＳ Ｇ ４０５１）をベースとする、Ｃ（炭素）を０．５０〜０．５８質量％、Ｓｉ（ケイ素）を０．１〜０．４質量％、Ｍｎ（マンガン）を０．５〜１．０質量％、Ｃｒ（クロム）を０．１〜０．４質量％、Ｐ（燐）を０．０３質量％以下、Ｓ（硫黄）を０．０３質量％以下、それぞれ含有し、酸素量（酸素濃度）を１５ｐｐｍ（好ましくは１２ｐｐｍ）以下に規制した合金鋼製としている。   The support shaft 4a of this example supported and fixed to the carrier 6a as described above is not made of high-carbon steel as in the conventional structure, but is based on S53C (JIS G 4051), which is a medium-carbon steel. C (carbon) is 0.50 to 0.58 mass%, Si (silicon) is 0.1 to 0.4 mass%, Mn (manganese) is 0.5 to 1.0 mass%, Cr ( Chromium) is 0.1 to 0.4 mass%, P (phosphorus) is 0.03 mass% or less, S (sulfur) is 0.03 mass% or less, and the oxygen amount (oxygen concentration) is 15 ppm (oxygen concentration). It is preferably made of alloy steel regulated to 12 ppm or less.

又、前記支持軸４ａのうち、各図に斜格子模様を付した範囲に、高周波焼き入れ処理による硬化層２２を形成している。具体的には、前記支持軸４ａの外周面のうち、前記各ニードル５、５の転動面が転がり接触する軌道面（両列の内輪軌道１０、１０）を含み、この軌道面よりも軸方向両側に広い範囲に、前記硬化層２２を全周に亙り形成している。但し、前記支持軸４ａの軸方向両端部（少なくともかしめ用筒部１５ａを含む部分）には前記硬化層２２を形成せず、軸方向両端部を生の状態（焼き入れ硬化していない状態）としている。この硬化層２２と生の部分との境界位置は、前記各支持壁部１８、１８の内側面２３、２３と、前記各面取り部１９、１９の内周縁部２４、２４との間部分（図２中のＸの範囲）に規制している。更に、本例の場合には、前記支持軸４ａの軸方向中間部に於ける前記硬化層２２の深さを、前記支持軸４ａの半径以上とする事で、この硬化層２２を、前記支持軸４ａの外周面（表層部分）だけでなく、この外周面から軸心部に至る範囲に形成している。即ち、高炭素クロム軸受鋼の様な硬質材料製の支持軸４の場合には、前記図７に斜格子模様で示した様に、硬化層を表層部にのみ形成し、軸心部には非硬化部を設けていたのに対し、本例の場合には、前記支持軸４ａの軸心部にも、非硬化部（生のままの部分）を設けていない。又、この支持軸４ａの軸方向両端寄り部分（硬化層２２の軸方向両端部）に於ける硬化層２２の深さは、軸方向端部側に向かう程浅くなる様にしている。   Further, a hardened layer 22 is formed by induction hardening in a range of the support shaft 4a in which each diagram is provided with a diagonal lattice pattern. Specifically, the outer peripheral surface of the support shaft 4a includes a raceway surface (both rows of inner ring raceways 10 and 10) in which the rolling surfaces of the needles 5 and 5 are in rolling contact with each other. The hardened layer 22 is formed over the entire circumference in a wide range on both sides in the direction. However, the hardened layer 22 is not formed on both end portions in the axial direction of the support shaft 4a (at least the portion including the caulking tube portion 15a), and both end portions in the axial direction are in a raw state (not quenched and hardened). It is said. The boundary position between the hardened layer 22 and the raw portion is a portion between the inner side surfaces 23 and 23 of the support wall portions 18 and 18 and the inner peripheral edge portions 24 and 24 of the chamfered portions 19 and 19 (see FIG. (Range of X in 2). Furthermore, in the case of this example, by setting the depth of the hardened layer 22 at the intermediate portion in the axial direction of the support shaft 4a to be equal to or greater than the radius of the support shaft 4a, the hardened layer 22 is supported by the support shaft 4a. Not only the outer peripheral surface (surface layer portion) of the shaft 4a but also the range from this outer peripheral surface to the shaft center portion. That is, in the case of the support shaft 4 made of a hard material such as a high carbon chrome bearing steel, a hardened layer is formed only on the surface layer portion as shown in the oblique lattice pattern in FIG. In contrast to the provision of the non-hardened portion, in the case of this example, the non-hardened portion (raw portion) is not provided also in the axial center portion of the support shaft 4a. In addition, the depth of the hardened layer 22 in the portions near both ends in the axial direction of the support shaft 4a (both ends in the axial direction of the hardened layer 22) is made shallower toward the end in the axial direction.

この様な硬化層２２は、前記支持軸４ａを構成する円柱状の素材の軸方向中間部周囲に、高周波加熱コイルを配置し、この高周波加熱コイルに高周波電源から高周波電力を供給する事により形成する。この場合、表層部にのみ硬化層を形成する場合に比べて、高周波加熱コイルを流れる高周波電流の周波数を低く設定する事で、前記支持軸４ａの軸心部にまで焼きを入れる。又、高周波焼き入れ後は、焼き戻し（低温焼き戻し）を施す。   Such a hardened layer 22 is formed by arranging a high-frequency heating coil around the middle portion in the axial direction of the cylindrical material constituting the support shaft 4a, and supplying high-frequency power from a high-frequency power source to the high-frequency heating coil. To do. In this case, as compared with the case where the hardened layer is formed only on the surface layer portion, the frequency of the high-frequency current flowing through the high-frequency heating coil is set to be low so that the shaft center portion of the support shaft 4a is baked. Further, after induction hardening, tempering (low temperature tempering) is performed.

以上の様な構成を有する本例の支持軸４ａによれば、耐久性を確保できるだけでなく、材料コストの低減を図れ、しかも加工時間を短縮できる。
即ち、本例の場合には、前記支持軸４ａを造る為の材料として、Ｃ（炭素）の含有量が０．５０〜０．５８質量％である合金鋼（中炭素鋼）を使用している為、高炭素クロム軸受鋼の様な高炭素鋼を材料として用いる従来構造の場合に比べて、材料コストの低減を図れる。 According to the support shaft 4a of the present example having the above-described configuration, it is possible not only to ensure durability but also to reduce the material cost and to shorten the processing time.
That is, in the case of this example, an alloy steel (medium carbon steel) having a C (carbon) content of 0.50 to 0.58 mass% is used as a material for producing the support shaft 4a. Therefore, the material cost can be reduced as compared with the conventional structure using high carbon steel such as high carbon chromium bearing steel.

又、前記支持軸４ａを構成する合金鋼は、Ｃの含有量が低く（高炭素クロム軸受鋼のＣ含有量は０．９５〜１．１０質量％であるのに対し、本例の合金鋼では０．５０〜０．５８質量％）、元々の（生の状態での）硬度が低い事に加え、軸方向両端部には高周波焼き入れ処理後も前記硬化層２２を形成しない。この為、前記各かしめ部９を形成する為の加工時間を短縮する事が可能になる。具体的には、高周波焼き入れ処理を施す以前の状態で、素材全体の硬度を十分に抑えられる為、軸方向両端面の中央に、円すい台形状の凹部１７ａ、１７ａを、鍛造加工（熱間鍛造加工或いは冷間鍛造加工）により形成する事が可能になる。この為、前記各凹部１７ａ、１７ａを切削加工により形成する場合に比べて、大幅な加工時間の短縮を図れる。又、切削加工により形成する場合にも、高炭素クロム軸受鋼の様な硬質材料を用いた場合に比べて、加工時間を短縮できる。更に、ボール盤等を使用した切削加工により、素材の内部に通油孔（例えば軸方向孔及び径方向孔）を形成する場合にも、高炭素クロム軸受鋼の様な硬質材料を用いた場合に比べて、やはり加工時間を短縮できる。   Further, the alloy steel constituting the support shaft 4a has a low C content (the C content of the high carbon chromium bearing steel is 0.95 to 1.10% by mass, whereas the alloy steel of this example) Then, in addition to the low hardness (in the raw state), the hardened layer 22 is not formed at both ends in the axial direction even after induction hardening. For this reason, it becomes possible to shorten the processing time for forming each said caulking part 9. Specifically, in order to sufficiently suppress the hardness of the entire material before the induction hardening process, a conical recess 17a, 17a is formed in the center of both axial end faces by forging (hot Forging or cold forging). For this reason, compared with the case where each said recessed part 17a, 17a is formed by cutting, the processing time can be shortened significantly. Also, when forming by cutting, the processing time can be shortened compared to the case of using a hard material such as high carbon chromium bearing steel. Furthermore, when oil-permeable holes (for example, axial holes and radial holes) are formed inside the material by cutting using a drilling machine, etc., when a hard material such as high carbon chromium bearing steel is used. Compared to this, the processing time can be shortened.

更に、上述の様な円すい台形状の凹部１７ａ、１７ａを形成する事に伴って、その周囲に形成されたかしめ用筒部１５ａ、１５ａは、高周波焼き入れ処理によっても硬化させない（生のままの状態である）為、これら各かしめ用筒部１５ａ、１５ａを径方向外方に塑性変形させる際の加工時間も短縮できる。即ち、これら各かしめ用筒部１５ａ、１５ａを塑性変形させるには、これら各かしめ用筒部１５ａ、１５ａの先端部に、図示しないかしめパンチを押し付ける等して行うが、本例の場合には、これら各かしめ用筒部１５ａ、１５ａの硬度を低く抑えられる為、これら各かしめ用筒部１５ａ、１５ａを、小さな押し付け力で塑性変形させる事が可能になり、加工時間を短縮できる。加えて、形成されるかしめ部９に割れや亀裂等の損傷が生じる事も防止できる。   Further, as the conical recesses 17a and 17a are formed as described above, the caulking cylinder portions 15a and 15a formed around the concave portions 17a and 17a are not hardened even by the induction hardening process (raw Therefore, the processing time for plastically deforming these caulking tube portions 15a, 15a radially outward can also be shortened. That is, in order to plastically deform these caulking cylinder portions 15a, 15a, it is performed by pressing a caulking punch (not shown) on the tip of each caulking cylinder portion 15a, 15a. Since the hardness of these caulking cylinder portions 15a and 15a can be kept low, it becomes possible to plastically deform these caulking cylinder portions 15a and 15a with a small pressing force, and the processing time can be shortened. In addition, it is possible to prevent damage such as cracks and cracks from occurring in the caulking portion 9 formed.

又、本例の場合には、Ｃ（炭素）の含有量を低く抑えるだけでなく、Ｓｉ（ケイ素）の含有量もその上限値を０．４質量％と低く抑えている為、この面からも、かしめ性が低下する事を防止できる。この為、前記各かしめ部９に、割れや亀裂等の損傷が生じる事を有効に防止できる。   In the case of this example, not only the content of C (carbon) is kept low, but also the content of Si (silicon) is kept at a lower limit of 0.4% by mass. However, it can prevent that caulking property falls. For this reason, it is possible to effectively prevent the caulking portions 9 from being damaged such as cracks or cracks.

又、前記支持軸４ａには、Ｃの含有量及びＳｉの含有量を軌道面に必要となる硬さを確保できる様に適正に規制した（Ｃの含有量の下限値を０．５０質量％とし、Ｓｉの含有量の上限値を０．４質量％とした）上で、高周波焼き入れによる硬化層２２を形成している為、軌道面部分（内輪軌道１０、１０）の表面硬さを、転がり疲れ寿命を確保するのに必要な硬さの目安となる、ビッカース硬度で６３３Ｈｖ（ロックウェル硬度で５７ＨＲＣ）以上に規制できる。又、軌道面部分に、疲労強度の向上に有利となる残留圧縮応力を発生させる事もできる。従って、転がり疲れ寿命を確保できて、耐久性を確保できる。   In addition, the support shaft 4a was appropriately regulated so that the hardness required for the raceway surface was secured for the C content and the Si content (the lower limit value of the C content was 0.50% by mass). Since the hardened layer 22 is formed by induction hardening on the upper limit of the Si content, the surface hardness of the raceway surface portions (inner ring raceways 10 and 10) is set. The Vickers hardness can be regulated to 633 Hv (Rockwell hardness 57 HRC) or more, which is a measure of the hardness necessary to ensure the rolling fatigue life. Further, residual compressive stress that is advantageous for improving the fatigue strength can be generated in the raceway surface portion. Therefore, a rolling fatigue life can be secured and durability can be secured.

又、前記支持軸４ａを構成する合金鋼中の酸素量を１５ｐｐｍ以下（より好ましくは１２ｐｐｍ以下）に規制している為、焼き入れされた軌道面（内輪軌道１０、１０）に、剥離の起点となる酸化物系の介在物が形成されにくくなる。この為、転がり疲れ寿命の更なる向上を図れる。この結果、高炭素クロム軸受鋼を材料として用いた場合と同等の、転がり疲れ寿命を確保する事が可能になる。   Further, since the amount of oxygen in the alloy steel constituting the support shaft 4a is regulated to 15 ppm or less (more preferably 12 ppm or less), the starting point of peeling on the hardened raceway surfaces (inner ring raceways 10 and 10). It becomes difficult to form oxide inclusions. For this reason, the rolling fatigue life can be further improved. As a result, it is possible to ensure a rolling fatigue life equivalent to the case where high carbon chromium bearing steel is used as a material.

又、本例の場合には、前記硬化層２２と生の部分との境界位置を、前記各支持壁部１８、１８の内側面２３、２３よりも外側（外側面側）に位置させている。この為、前記遊星歯車３から前記支持軸４ａに加わるラジアル荷重に起因して、この支持軸４ａのうちで、前記各支持孔８ｃ、８ｃに内嵌された部分と内嵌されていない部分との境界に過大な応力が加わった場合にも、当該部分が損傷する事を有効に防止できる。   In the case of this example, the boundary position between the hardened layer 22 and the raw part is located outside (outer surface side) of the inner side surfaces 23 and 23 of the support wall portions 18 and 18. . For this reason, due to the radial load applied from the planetary gear 3 to the support shaft 4a, portions of the support shaft 4a that are fitted in the support holes 8c and 8c and portions that are not fitted in the support shaft 4a. Even when an excessive stress is applied to the boundary, the portion can be effectively prevented from being damaged.

又、前記硬化層２２を前記支持軸４ａの軸心部にまで形成している為、この支持軸４ａの強度（主として曲げ強度）を十分に向上させる事が可能になる。又、軸方向中間部分の残留オーステナイト量が、軸方向両端部分の残留オーステナイト量に比べて多くなり、軸方向中央部分の外周面が凸となる様に僅かに（緩やかに）膨出する為、軌道面にエッジロードが発生する事を防止する面からも有利になる（クラウニング効果が得られる）。   Further, since the hardened layer 22 is formed up to the axial center of the support shaft 4a, the strength (mainly bending strength) of the support shaft 4a can be sufficiently improved. In addition, the amount of retained austenite in the axial middle portion is larger than the amount of retained austenite at both axial end portions, and the outer peripheral surface of the axial central portion bulges slightly (slowly) so that it protrudes. It is also advantageous in terms of preventing the occurrence of edge loading on the raceway surface (a crowning effect can be obtained).

更に、本例の場合には、Ｃ（炭素）以外の成分（Ｓｉ、Ｍｎ、Ｃｒ）に関しても、それぞれの含有量を適正に規制している為、品質のばらつきを抑える事ができる。例えばＳＫ８５（ＪＩＳ Ｇ ４４０１、Ｃの含有量が０．８０〜０．９０質量％の高炭素鋼）と比較しても、熱処理品質を安定させる事ができて、従来構造の場合と同等の耐久性を確保できる。   Furthermore, in the case of this example, since the respective contents of components (Si, Mn, Cr) other than C (carbon) are appropriately regulated, variation in quality can be suppressed. For example, even compared with SK85 (JIS G 4401, high carbon steel with a C content of 0.80 to 0.90 mass%), the heat treatment quality can be stabilized and the durability equivalent to that of the conventional structure can be obtained. Can be secured.

尚、上述した実施の形態の１例では、遊星歯車をキャリアに対して回転自在に支持する為に用いる支持軸に、本発明を適用した場合に就いて説明したが、本発明の回転部材用支持軸は、この様な用途に限定されるものではない。例えば、エンジンの動弁機構用のカムフォロアをロッカーアームに対して回転自在に支持する為に用いる支持軸の他、エンジンの動弁機構用のローラをバルブリフタに対して回転自在に支持する為の支持軸、更には、エンジン燃料噴射ポンプ用のカムローラをプランジャの端部に連結されたタペットに対して回転自在に支持する為の支持軸に対しても、本発明は適用可能である。   In the example of the above-described embodiment, the case where the present invention is applied to the support shaft used for rotatably supporting the planetary gear with respect to the carrier has been described. The support shaft is not limited to such an application. For example, in addition to the support shaft used to rotatably support the cam follower for the valve mechanism of the engine with respect to the rocker arm, the support for rotatably supporting the roller for the valve mechanism of the engine with respect to the valve lifter The present invention can also be applied to a shaft, and further to a support shaft for rotatably supporting a cam roller for an engine fuel injection pump with respect to a tappet connected to an end of a plunger.

次に、本発明の効果を確認する為に行った２種類の試験に就いて説明する。
第１の試験は、次の表１に示した１２種類（実施例１〜６並びに比較例１〜６）の合金鋼により、外径が１２ｍｍ、長さが５０ｍｍで、それぞれの軸方向両端部に前記図１に示した様な形状を有するかしめ用筒部を設けた支持軸を５本ずつ造り、かしめ用筒部を径方向外方に塑性変形させた際の損傷の発生の有無を検証した。又、本試験では、何れの試料に就いても、かしめ用筒部を生のまま塑性変形させた。又、この場合のかしめ用筒部のビッカース硬度は、２００〜３５０Ｈｖであった。又、かしめ用筒部に負荷する荷重（かしめ荷重）は、何れの場合も２５ｋＮとした。 Next, two types of tests conducted to confirm the effect of the present invention will be described.
The first test was performed using 12 kinds of alloy steels shown in the following Table 1 (Examples 1 to 6 and Comparative Examples 1 to 6), each having an outer diameter of 12 mm and a length of 50 mm. 5 each of the support shafts provided with the caulking cylinder portion having the shape as shown in FIG. 1, and verifying whether or not damage has occurred when the caulking cylinder portion is plastically deformed radially outward. did. Further, in this test, the caulking tube portion was plastically deformed with respect to any sample. In this case, the caulking tube portion had a Vickers hardness of 200 to 350 Hv. Moreover, the load (caulking load) applied to the caulking cylinder portion was 25 kN in any case.

［表１］

[Table 1]

試験の結果を、前記表１の右側部分（右から第２列目）に示した様に、本発明の実施品である、実施例１〜６の支持軸には、５本全ての試料（支持軸）に関して、亀裂や割れは認められなかった。これは、Ｃ及びＳｉの含有量を、軌道面に必要となる表面硬さを得られる範囲で、十分に低く抑えた事により、割れ特性が向上した事によるものと考えられる。   As shown in the right part (second column from the right) of Table 1, the test results are shown in the support shafts of Examples 1 to 6, which are products of the present invention. Regarding the support shaft), no cracks or cracks were observed. This is considered to be because the cracking characteristics were improved by suppressing the C and Si contents sufficiently low within the range in which the surface hardness required for the raceway surface was obtained.

これに対し、比較例１（ＳＫ８５製）及び比較例２（ＳＵＪ２製）の支持軸は、Ｃの含有量が高い（本発明の上限値である０．５８質量％を大幅に超えている）事から、かしめ用筒部の硬度（特に表層部の硬度）が高くなり、かしめ加工性が悪化したと考えられ、５本の試料中、４本（比較例１）又は５本（比較例２）の試料で、割れが発生した。
又、比較例３の支持軸は、Ｓｉの含有量が０．６質量％と高い為、かしめ用筒部の変形抵抗が大きくなったと考えられ、５本の試料中、１本の試料で亀裂が発生した。
又、比較例４の支持軸は、Ｃの含有量が僅かに高い（本発明の上限値である０．５８質量％を僅かに超えている）為、かしめ用筒部の硬度（特に表層部の硬度）が高くなり、かしめ加工性が悪化したと考えられ、５本の試料中、１本の試料で亀裂が発生した。
一方、比較例５、６の支持軸は、Ｃの含有量が本発明の下限値を下回っており、Ｓｉの含有量も本発明の範囲に含まれている為、かしめ用筒部の硬度が低くなったと考えられ、５本全ての試料に関して、亀裂や割れは認められなかった。
上述の様なかしめ割れ試験（第１の試験）の結果から明らかな通り、本発明の様に、Ｃ及びＳｉの含有量を、軌道面の表面硬さを確保できる範囲で低く抑える事により、かしめ性が低下する事を防止できて、かしめ部に割れや亀裂等の損傷が生じる事を有効に防止できる。 In contrast, the support shafts of Comparative Example 1 (manufactured by SK85) and Comparative Example 2 (manufactured by SUJ2) have a high C content (which greatly exceeds the upper limit of 0.58% by mass of the present invention). From the above, it is considered that the hardness of the caulking cylinder portion (particularly the hardness of the surface layer portion) was increased, and the caulking workability was considered to be deteriorated, among 4 samples, 4 (Comparative Example 1) or 5 (Comparative Example 2). ) Cracks occurred in the sample.
Further, the support shaft of Comparative Example 3 is considered to have increased deformation resistance of the caulking cylinder part because of the high Si content of 0.6% by mass. There has occurred.
Further, since the support shaft of Comparative Example 4 has a slightly high C content (slightly exceeding the upper limit of 0.58% by mass of the present invention), the hardness of the caulking tube portion (particularly the surface layer portion) It was considered that the caulking workability deteriorated, and cracks occurred in one of the five samples.
On the other hand, in the support shafts of Comparative Examples 5 and 6, the C content is below the lower limit of the present invention, and the Si content is also included in the scope of the present invention. It was considered that the crack was lowered, and no cracks or cracks were observed for all five samples.
As is clear from the results of the caulking crack test (first test) as described above, as in the present invention, by suppressing the content of C and Si as low as possible to ensure the surface hardness of the raceway surface, It can prevent that caulking property falls, and can prevent effectively that damage, such as a crack and a crack, arises in a caulking part.

第２の試験は、次の表２に示した１２種類（実施例１〜６並びに比較例１〜６）の合金鋼により、外径が１２ｍｍ、長さが５０ｍｍの支持軸を３本ずつ造り、図４に示す様な、試験装置２５を用いて、軌道面（内輪軌道）の耐久性寿命を求めた。又、図４に示した様に、本試験では、各種試料である支持軸４ａ（４）の内部に、潤滑油を送り込む為の通油孔として機能する軸方向孔２６及び径方向孔２７を形成した。これに伴い、軸方向孔２６が設けられている軸方向片半部（図４の左半部）には、前記各支持軸４ａ（４）の外周面から軸方向孔２６に至る範囲に硬化層２２を形成した（図示は省略）。   In the second test, three support shafts each having an outer diameter of 12 mm and a length of 50 mm are made of 12 kinds of alloy steels shown in Table 2 (Examples 1 to 6 and Comparative Examples 1 to 6). The durability life of the raceway surface (inner ring raceway) was determined using a test apparatus 25 as shown in FIG. Further, as shown in FIG. 4, in this test, an axial hole 26 and a radial hole 27 functioning as oil passage holes for feeding the lubricating oil into the support shaft 4a (4), which are various samples, are formed. Formed. Accordingly, the half of the axial direction (the left half of FIG. 4) provided with the axial hole 26 is cured to the range from the outer peripheral surface of each support shaft 4a (4) to the axial hole 26. Layer 22 was formed (not shown).

［表２］

[Table 2]

前記試験装置２５は、１対の支持部材（治具）２８ａ、２８ｂと、回転部材に相当する円筒状の外輪２９と、複数個のニードル５、５から成るラジアルニードル軸受１２と、温度測定器３０とを備えるもので、このうちの支持部材２８ａ、２８ｂの互いに対向する内側面には、前記各支持軸４ａ（４）の軸方向端部を支持する為の支持凹部３１、３１が形成されている。又、１対の支持部材２８ａ、２８ｂのうち、一方の支持部材２８ａの内部には、潤滑油を送り込む為の油孔３２が形成されており、他方の支持部材２８ｂの内部には、前記温度測定器３０の検出部を挿通させる為の挿通孔３３が形成されている。   The test device 25 includes a pair of support members (jigs) 28a and 28b, a cylindrical outer ring 29 corresponding to a rotating member, a radial needle bearing 12 including a plurality of needles 5 and 5, and a temperature measuring device. 30 are formed on the inner surfaces of the support members 28a and 28b opposite to each other, and support recesses 31 and 31 for supporting the axial ends of the support shafts 4a (4) are formed. ing. Of the pair of support members 28a and 28b, one support member 28a is provided with an oil hole 32 for feeding lubricating oil, and the other support member 28b has the above temperature. An insertion hole 33 for inserting the detection unit of the measuring device 30 is formed.

そして、前記各支持軸４ａ（４）の軸方向両端部を、前記各支持凹部３１、３１に内嵌固定する事により、これら各支持軸４ａ（４）を前記各支持部材２８ａ、２８ｂに支持固定する。この状態で、一方の支持部材２８ａに形成された油孔３２と、前記各支持軸４ａ（４）に形成された軸方向孔２６及び径方向孔２７とを連通させる。又、これら各支持軸４ａ（４）の軸方向方向中間部周囲に、前記ラジアルニードル軸受１２を介して、前記外輪２９を回転自在に支持する。更に、他方の支持部材２８ｂに形成された挿通孔３３内に、前記温度測定器３０の検出部を挿通させて、この検出部を前記各支持軸４ａ（４）の軸方向端面｛円すい台形状の凹部１７ａ（１７）の底面｝に当接させる。試験時には、これら各支持軸４ａ（４）を固定した状態のまま、前記各孔３２、２６、２７を通じて潤滑油を供給しつつ、前記外輪２９を、ラジアル荷重を負荷しながら回転させる。そして、軌道面に剥離が生じる迄の時間を寿命として評価した。   Then, both end portions in the axial direction of the support shafts 4a (4) are fitted and fixed to the support recesses 31 and 31, respectively, so that the support shafts 4a (4) are supported by the support members 28a and 28b. Fix it. In this state, the oil hole 32 formed in one of the support members 28a and the axial hole 26 and the radial hole 27 formed in each of the support shafts 4a (4) are communicated. Further, the outer ring 29 is rotatably supported through the radial needle bearing 12 around the intermediate portion in the axial direction of each of the support shafts 4a (4). Further, the detection part of the temperature measuring device 30 is inserted into the insertion hole 33 formed in the other support member 28b, and this detection part is connected to the axial end face {conical trapezoidal shape of each support shaft 4a (4). Are brought into contact with the bottom surface of the recess 17a (17). At the time of the test, the outer ring 29 is rotated while applying a radial load while supplying the lubricating oil through the holes 32, 26, 27 while the support shafts 4a (4) are fixed. Then, the time until peeling occurred on the raceway surface was evaluated as the lifetime.

上述した様な耐久寿命試験の試験条件は、以下の通りである。
ラジアル荷重（動等価ラジアル荷重Ｐ／基本動定格荷重Ｃｒ） ： ０．３
外輪２９の回転速度 ： １００００ｍｉｎ^−１
試験温度 ： １２０℃
潤滑油の送り込み量 ： １００ｃｃ／ｍｉｎ
試験終了の条件 ： 計算寿命である９２ｈｒの２倍（１８４ｈｒ）に達するか、軌道面に剥離が認められた時点で終了
使用したニードル５、５の寸法 ： 外径２．５ｍｍ、長さ９．８ｍｍ
軌道面の表面粗さ（算術平均粗さ） ： ０．１５μｍＲａ
熱処理条件 ： 全ての試料（実施例及び比較例）に関して、同じ熱処理条件（温度、時間及び範囲）にて高周波焼き入れ処理を施した。 The test conditions of the durability life test as described above are as follows.
Radial load (dynamic equivalent radial load P / basic dynamic load rating Cr): 0.3
Rotational speed of outer ring 29: 10000 min ⁻¹
Test temperature: 120 ° C
Lubricating oil feed rate: 100cc / min
Conditions for the end of the test: When the calculated life reached twice twice (184 hours) (184 hours) or when the surface of the raceway was peeled off, the dimensions of the needles 5 and 5 used: an outer diameter of 2.5 mm and a length of 9. 8mm
Surface roughness of the raceway surface (arithmetic mean roughness): 0.15 μmRa
Heat treatment conditions: All samples (Examples and Comparative Examples) were subjected to induction hardening treatment under the same heat treatment conditions (temperature, time and range).

以上の様にして行った試験の結果を、前記表２の右側部分（右から第２列目）に示した様に、本発明の実施品のうち、実施例１に関しては、軌道面の表面硬さがビッカース硬度で６３３Ｈｖであり、合金鋼中の酸素量が１５ｐｐｍに抑えられている為、軌道面に剥離が発生するまでの時間が１７０ｈｒ（Ｌ１０＝１７０ｈｒ）となった。この為、比較例１、３〜６と比較して寿命は２倍以上となり、十分な耐久性を確保できる事が確認された。
又、実施例２〜６に関しては、軌道面の表面硬さがビッカース硬度で６６０〜８５０Ｈｖと十分に硬く、又、合金鋼中の酸素量が１２ｐｐｍ以下に抑えられている為、計算寿命９２ｈｒの２倍（１８４ｈｒ）に達しても、軌道面に剥離は発生しなかった。この為、比較例１、３〜６と比較して、顕著に耐久性が向上している事が確認された。 As shown in the right part (second column from the right) of Table 2 above, the results of the tests performed as described above are as follows. Since the hardness was 633 Hv in terms of Vickers hardness and the oxygen content in the alloy steel was suppressed to 15 ppm, the time until separation occurred on the raceway surface was 170 hr (L10 = 170 hr). For this reason, compared with the comparative examples 1 and 3-6, the lifetime became 2 times or more, and it was confirmed that sufficient durability can be ensured.
In addition, regarding Examples 2 to 6, the surface hardness of the raceway surface is sufficiently hard at 660 to 850 Hv in terms of Vickers hardness, and the oxygen content in the alloy steel is suppressed to 12 ppm or less, so that the calculated lifetime is 92 hours. Even when it reached twice (184 hours), no peeling occurred on the raceway surface. For this reason, it was confirmed that the durability was remarkably improved as compared with Comparative Examples 1 and 3-6.

これに対し、比較例１（ＳＫ８５製：本試験では酸素量が管理されていないものを使用）及び比較例４に関しては、合金鋼中の酸素量がそれぞれ３４ｐｐｍ、３５ｐｐｍと高い（本発明の上限値である１５ｐｐｍを大幅に超えている）事から、軌道面に剥離の起点となる酸化物系の介在部が早期に形成されたと考えられ、寿命は計算寿命（９２ｈｒ）以下の８５ｈｒ、８０ｈｒとなった。
又、比較例２に関しては、ＳＵＪ２（高炭素クロム軸受鋼２種）製であり、軌道面の表面硬さがビッカース硬度で８５０Ｈｖで、酸素量も９ｐｐｍと低い事から、計算寿命である９２ｈｒの２倍（１８４ｈｒ）に達しても、軌道面に剥離は発生しなかった。但し、前述した第１の試験（かしめ割れ試験）で明らかになった様に、支持軸をＳＵＪ２製とした場合には、Ｃの含有量が多くなり過ぎる事から、かしめ加工性が悪化する。
又、比較例３、５、６に関しては、合金鋼中の酸素量は、本発明の範囲に含まれている（１５ｐｐｍである）ものの、比較例３にあっては、Ｓｉの含有量が本発明の上限値を超えており、比較例５、６にあっては、Ｃの含有量が本発明の下限値を下回っている。この為、比較例３の場合には、Ｓｉの含有量が高い事で、高周波焼き入れ処理の際に、Ｓｉの溶け込みが不足し、巨大なＳｉＣが析出した為、軌道面の表面硬さがビッカース硬度で６００Ｈｖと低くなり、転がり軸受として要求される硬さが得られていない。又、比較例５、６の場合には、Ｃの含有量が十分でない事から、軌道面の表面硬さがビッカース硬度で５８０Ｈｖ、５５０Ｈｖと低くなり、やはり十分な硬さが得られていない。この結果、引用例３、５、６の場合には、それぞれ８３ｈｒ、６５ｈｒ、５９ｈｒにて軌道面に剥離が発生し、何れの場合にも計算寿命よりも短寿命となった。
上述の様な耐久寿命試験（第２の試験）の結果から明らかな通り、本発明の様に、Ｃの含有量の下限値及びＳｉの上限値を適正に規制して、軌道面に必要となる表面硬さを確保する（ビッカース硬度で６３３Ｈｖ以上とする）と共に、酸素量を１５ｐｐｍ以下に抑える事によって、転がり疲れ寿命を確保できて、耐久性を十分に確保できる。 On the other hand, as for Comparative Example 1 (manufactured by SK85: use of which oxygen amount is not controlled in this test) and Comparative Example 4, the oxygen amount in the alloy steel is as high as 34 ppm and 35 ppm, respectively (the upper limit of the present invention). It is considered that the oxide-based intervening portion that becomes the starting point of separation was formed early on the raceway surface, and the lifetime was 85 hr and 80 hr below the calculated lifetime (92 hr). became.
Further, as for Comparative Example 2, it is made of SUJ2 (high carbon chromium bearing steel type 2), the surface hardness of the raceway surface is 850 Hv in Vickers hardness, and the oxygen content is as low as 9 ppm. Even when it reached twice (184 hours), no peeling occurred on the raceway surface. However, as is apparent from the first test (caulking crack test) described above, when the support shaft is made of SUJ2, the caustic processability deteriorates because the C content is excessive.
For Comparative Examples 3, 5, and 6, the oxygen content in the alloy steel is included in the scope of the present invention (15 ppm), but in Comparative Example 3, the Si content is The upper limit of the invention is exceeded, and in Comparative Examples 5 and 6, the C content is lower than the lower limit of the invention. For this reason, in the case of the comparative example 3, since the Si content is high, during the induction hardening process, the Si does not dissolve sufficiently, and a huge amount of SiC is precipitated. Vickers hardness is as low as 600 Hv, and the hardness required for rolling bearings is not obtained. In Comparative Examples 5 and 6, since the C content is not sufficient, the surface hardness of the raceway surface is as low as 580 Hv and 550 Hv in Vickers hardness, and sufficient hardness is not obtained. As a result, in Reference Examples 3, 5, and 6, separation occurred on the raceway surface at 83 hr, 65 hr, and 59 hr, respectively, and in each case, the lifetime was shorter than the calculated lifetime.
As is clear from the results of the endurance life test (second test) as described above, the lower limit value of the C content and the upper limit value of Si are appropriately regulated as in the present invention, and it is necessary for the raceway surface. In addition to ensuring the surface hardness (Vickers hardness is 633 Hv or more) and suppressing the oxygen amount to 15 ppm or less, it is possible to ensure a rolling fatigue life and sufficiently ensure durability.

１ 太陽歯車
１ａ 歯
２ リング歯車
２ａ 歯
３ 遊星歯車
３ａ 歯
４、４ａ 支持軸
５ ニードル
６、６ａ キャリア
７ 連結板
８ａ〜８ｃ 通孔
９ かしめ部
１０ 内輪軌道
１１ 外輪軌道
１２ ラジアルニードル軸受
１３ 円筒部
１４ 回転軸
１５、１５ａ かしめ用筒部
１６、１６ａ 軸方向端面
１７、１７ａ 凹部
１８ 支持壁部
１９ 面取り部
２０ ワッシャ
２１ スペーサ
２２ 硬化層
２３ 内側面
２４ 内周縁部
２５ 試験装置
２６ 軸方向孔
２７ 径方向孔
２８ａ、２８ｂ 支持部材
２９ 外輪
３０ 温度測定器
３１ 支持凹部
３２ 油孔
３３ 挿通孔 DESCRIPTION OF SYMBOLS 1 Sun gear 1a Tooth 2 Ring gear 2a Tooth 3 Planetary gear 3a Tooth 4, 4a Support shaft 5 Needle 6, 6a Carrier 7 Connection board 8a-8c Through-hole 9 Caulking part 10 Inner ring track 11 Outer ring track 12 Radial needle bearing 13 Cylindrical part DESCRIPTION OF SYMBOLS 14 Rotating shaft 15, 15a Caulking cylinder part 16, 16a Axial end face 17, 17a Recess 18 Support wall part 19 Chamfering part 20 Washer 21 Spacer 22 Hardened layer 23 Inner side face 24 Inner peripheral edge part 25 Test apparatus 26 Axial hole 27 Diameter Direction hole 28a, 28b Support member 29 Outer ring 30 Temperature measuring device 31 Support recess 32 Oil hole 33 Insertion hole

Claims (3)

互いに離隔して設けられた１対の支持壁部の互いに整合する位置に形成された１対の通孔にその軸方向両端部を内嵌した状態で、この軸方向両端部の外周縁部分を径方向外方にかしめ拡げる事で、前記１対の支持壁部同士の間に掛け渡された状態で支持固定され、軸方向中間部周囲に回転部材をラジアルニードル軸受を介して回転自在に支持する回転部材用支持軸に於いて、
Ｃを０．５０〜０．５８質量％、Ｓｉを０．１〜０．４質量％、Ｍｎを０．５〜１．０質量％、Ｃｒを０．１〜０．４質量％含有する合金鋼製で、
外周面のうちで、前記ラジアルニードル軸受を構成する各ニードルの転動面が転がり接触する軌道面を含みこの軌道面よりも軸方向両側に広い範囲で、且つ、軸方向両端部を除く部分に、高周波焼き入れ処理による硬化層が全周に亙り形成されている
事を特徴とする回転部材用支持軸。 In the state where both ends in the axial direction are fitted in a pair of through-holes formed at positions aligned with each other in a pair of support wall portions provided apart from each other, the outer peripheral edge portions of the both ends in the axial direction are By caulking outward in the radial direction, the support wall is supported and fixed in a state of being spanned between the pair of support wall portions, and the rotating member is rotatably supported around the intermediate portion in the axial direction via a radial needle bearing. In the support shaft for the rotating member
Alloy containing C of 0.50 to 0.58 mass%, Si of 0.1 to 0.4 mass%, Mn of 0.5 to 1.0 mass%, and Cr of 0.1 to 0.4 mass% Made of steel,
The outer peripheral surface includes a raceway surface on which the rolling surface of each of the needles constituting the radial needle bearing is in rolling contact with a range that is wider on both sides in the axial direction than the raceway surface, and a portion excluding both end portions in the axial direction. A support shaft for a rotating member, characterized in that a hardened layer formed by induction hardening is formed over the entire circumference. 酸素量が１５ｐｐｍ以下である、請求項１に記載した回転部材用支持軸。   The support shaft for a rotating member according to claim 1, wherein the oxygen amount is 15 ppm or less. 硬化層が回転部材用支持軸の外周面から軸心部に至る範囲に形成されている、請求項１〜２のうちの何れか１項に記載した回転部材用支持軸。   The rotating member support shaft according to claim 1, wherein the hardened layer is formed in a range from the outer peripheral surface of the rotating member support shaft to the shaft center portion.

Images