JP2006250332A - Hollow power transmission shaft - Google Patents

Hollow power transmission shaft Download PDF

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JP2006250332A
JP2006250332A JP2005071533A JP2005071533A JP2006250332A JP 2006250332 A JP2006250332 A JP 2006250332A JP 2005071533 A JP2005071533 A JP 2005071533A JP 2005071533 A JP2005071533 A JP 2005071533A JP 2006250332 A JP2006250332 A JP 2006250332A
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power transmission
transmission shaft
boot
diameter portion
small diameter
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Katsuhiro Sakurai
勝弘 櫻井
Akira Nakagawa
亮 中川
Kazuhiko Yoshida
和彦 吉田
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NTN Corp
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NTN Corp
NTN Toyo Bearing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow power transmission shaft securing static strength and dynamic strength. <P>SOLUTION: A small diameter part 1b of a power transmission shaft 1 comprises: a connecting part 1d on an end part side to be connected with a joint; an axially-intermediate-part-side boot fixing part 1e to which a boot is fixed; and a minimum diameter part 1f between the connecting part 1d and the boot fixing part 1e. The power transmission shaft 1 has a hardened layer S formed by heat treatment over almost all area L in an axial direction. Almost all area L in the axial direction of the power transmission shaft 1 is subjected to quenching by high-frequency induction heating method and then the connecting part 1d and the boot fixing part 1e of the small diameter part 1b are locally subjected to tempering by the high-frequency induction heating method, so as to form the hardened layer S. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、等速自在継手等の継手に連結される中空状動力伝達シャフトに関し、例えば、自動車の動力伝達系を構成するドライブシャフト（駆動軸）やプロペラシャフト（推進軸）に適用することができる。   The present invention relates to a hollow power transmission shaft connected to a joint such as a constant velocity universal joint, and can be applied to, for example, a drive shaft (drive shaft) and a propeller shaft (propulsion shaft) constituting a power transmission system of an automobile. it can.

例えば、自動車の動力伝達系において、減速装置（ディファレンシャル）から駆動輪に動力を伝達する動力伝達シャフトは、ドライブシャフト（駆動軸）と呼ばれることがある。特に、ＦＦ車に使用されるドライブシャフトでは、前輪操舵時に大きな作動角と等速性が要求され、また、懸架装置との関係で軸方向の変位を吸収する機能が要求されるので、その一端部をダブルオフセット型等速自在継手やトリポード型等速自在継手等の摺動型等速自在継手を介して減速装置側に連結し、その他端部をバーフィールド型等速自在継手（ゼッパジョイントと呼ばれることもある。）等の固定側等速自在継手を介して駆動輪側に連結する機構が多く採用されている。   For example, in a power transmission system of an automobile, a power transmission shaft that transmits power from a speed reducer (differential) to drive wheels may be called a drive shaft (drive shaft). In particular, a drive shaft used in an FF vehicle requires a large operating angle and constant velocity during front wheel steering, and also requires a function of absorbing axial displacement in relation to the suspension system. Is connected to the reducer side through a sliding type constant velocity universal joint such as a double offset type constant velocity universal joint or a tripod type constant velocity universal joint, and the other end is connected to a barfield type constant velocity universal joint (Zepper joint). In many cases, a mechanism that is connected to the drive wheel side via a fixed-side constant velocity universal joint is employed.

上記のようなドライブシャフトとしては、従来、また現在においても、中実シャフトが多く使用されているが、自動車の軽量化、ドライブシャフトの剛性増大による機能向上、曲げ一次固有振動数のチューニング最適化による車室内の静粛性向上等の観点から、近時では、ドライブシャフトを中空シャフト化する要求が増えてきている。   As a drive shaft as described above, a solid shaft is often used in the past and now, but the weight of the car is improved, the function is improved by increasing the rigidity of the drive shaft, and the tuning of the bending primary natural frequency is optimized. Recently, there has been an increasing demand for a drive shaft to be a hollow shaft from the viewpoint of improving the quietness of the interior of the vehicle.

ドライブシャフト等に適用される中空状動力伝達シャフトとしては、例えば、下記の特許文献１に記載されたものが知られている。   As a hollow power transmission shaft applied to a drive shaft or the like, for example, one described in Patent Document 1 below is known.

特許文献１に記載された中空状動力伝達シャフトは、軸方向中間部が大径部に形成され、軸方向両側部がそれぞれ小径部に形成されている。小径部は、継手が連結される端部の連結部と、ブーツが固定される大径部側のブーツ固定部と、連結部とブーツ固定部との間の最小径部とを有している。特許文献１では、中空状動力伝達シャフトの軸方向のほぼ全域に亘って高周波焼入れ・焼戻し処理を行い、外周表面から内周面表面に至る肉厚全体に硬化処理を施している（同文献の段落番号００１２参照）。
特開２００２―３４９５３８号公報 The hollow power transmission shaft described in Patent Document 1 has an axial middle portion formed in a large diameter portion and both axial side portions formed in small diameter portions. The small-diameter portion has a connecting portion at an end to which the joint is connected, a boot fixing portion on the large-diameter portion side to which the boot is fixed, and a minimum diameter portion between the connecting portion and the boot fixing portion. . In Patent Document 1, induction hardening and tempering treatment is performed over almost the entire axial direction of the hollow power transmission shaft, and the entire thickness from the outer peripheral surface to the inner peripheral surface is subjected to hardening treatment (see the same document). (See paragraph 0012).
JP 2002-349538 A

一般に、この種の中空状動力伝達シャフトは、捩り疲労強度等の動的強度に対しては、動力伝達部となる軸端部の連結部が最弱部となり、静的捩り強度等の静的強度に対しては、軸径が最も小径となる最小径部が最弱部となる。従って、連結部については硬度と靭性の確保が重要であり、最小径部については硬度の確保が重要である。この点、特許文献１では、中空状動力伝達シャフトの軸方向ほぼ全域について高周波焼入れ・焼戻し処理を行なっているので、焼戻しの際に最小径部の硬度も低下してしまい、使用条件によっては静的強度が不足する場合があった。その一方で、焼戻し処理を廃止すると、連結部の靭性が低下して必要な動的強度が得られず、また、形状が複雑なブーツ固定部に焼割れ等が発生する場合もあった。   In general, this type of hollow power transmission shaft has a weakest portion at the shaft end connecting portion serving as a power transmission portion with respect to dynamic strength such as torsional fatigue strength. For strength, the smallest diameter portion with the smallest shaft diameter is the weakest portion. Therefore, it is important to secure hardness and toughness for the connecting portion, and it is important to secure hardness for the minimum diameter portion. In this regard, in Patent Document 1, since the induction hardening and tempering treatment is performed on almost the entire axial direction of the hollow power transmission shaft, the hardness of the minimum diameter portion also decreases during tempering, and depending on the use conditions, In some cases, the mechanical strength was insufficient. On the other hand, if the tempering treatment is abolished, the toughness of the connecting portion is lowered and the necessary dynamic strength cannot be obtained, and tempering cracks may occur in the boot fixing portion having a complicated shape.

本発明の課題は、静的強度と動的強度を共に確保した中空状動力伝達シャフトを提供することである。   An object of the present invention is to provide a hollow power transmission shaft that ensures both static strength and dynamic strength.

上記課題を解決するため、本発明は、軸方向中間部が大径部に形成されると共に、大径部よりも軸方向両側部がそれぞれ小径部に形成され、小径部は、継手が連結される端部の連結部と、ブーツが固定される大径部側のブーツ固定部と、連結部とブーツ固定部との間の最小径部とを有する中空状動力伝達シャフトにおいて、大径部及び小径部に焼入処理を施した後、小径部の連結部とブーツ固定部のうち、少なくとも連結部に局部的に焼戻し処理を施した構成を提供する。   In order to solve the above-mentioned problems, the present invention has an axial intermediate portion formed in a large diameter portion, and axially opposite side portions are formed in a small diameter portion with respect to the large diameter portion, and the small diameter portion is connected to a joint. A hollow power transmission shaft having a connecting portion at an end portion, a boot fixing portion on the large diameter portion side where the boot is fixed, and a minimum diameter portion between the connecting portion and the boot fixing portion. Provided is a configuration in which after the quenching process is performed on the small diameter part, at least the coupling part is locally tempered among the coupling part of the small diameter part and the boot fixing part.

動力伝達部となる連結部には局部的に焼戻し処理を施することにより、焼入れ後の不安定な組織状態が改善され、焼割れ、置き割れ、経年変化の心配が解消されると同時に、必要な靭性が確保され、捩り疲労強度等の動的強度が確保される。さらに、ブーツ固定部に対しても局部的に焼戻し処理を施することにより、焼入れ後の不安定な組織状態が改善され、焼割れ、置き割れ、経年変化の心配が解消される。一方、最小径部は焼入れ状態のまま残されるので、必要な硬度が確保され、静的捩り強度等の静的強度が確保される。   By applying tempering treatment locally to the connecting part that becomes the power transmission part, the unstable structure after quenching is improved, and the concerns about tempering cracks, cracking, and secular change are eliminated, and it is necessary. Dynamic toughness such as torsional fatigue strength is ensured. Further, by locally tempering the boot fixing part, the unstable structure after quenching is improved, and the fear of tempering cracks, cracking, and secular change is eliminated. On the other hand, since the minimum diameter portion is left in the quenched state, necessary hardness is ensured, and static strength such as static torsional strength is ensured.

本発明の中空状動力伝達シャフトは、例えば、鋼製のパイプ素材に塑性加工を施して、軸方向中間部に大径部、軸方向両側部に小径部を有する中空状シャフト素材を成形し、この中空状シャフト素材に所要の機械加工を施して連結部やブーツ固定部等を成形した後、焼入れ処理と、連結部（及びブーツ固定部）に局部的な焼戻し処理を施すことによって製造される。   The hollow power transmission shaft of the present invention is formed, for example, by forming a hollow shaft material having a large diameter portion in the middle portion in the axial direction and a small diameter portion on both side portions in the axial direction by subjecting the steel pipe material to plastic processing. The hollow shaft material is manufactured by subjecting the hollow shaft material to required machining to form a connecting portion, a boot fixing portion, and the like, followed by quenching and local tempering processing on the connecting portion (and the boot fixing portion). .

上記の塑性加工としては、スウェージング加工やプレス加工等が採用される。前者のスウェージング加工には、ロータリースウェージングとリンクタイプスウェージングがあり、その何れも採用することができる。   As the plastic processing, swaging processing, press processing, or the like is employed. The former swaging process includes rotary swaging and link type swaging, both of which can be employed.

例えば、ロータリースウェージングは、機内の主軸に組込まれた一対又は複数対のダイスとバッカーとが回転運動を行なうと共に、外周ローラとバッカー上の突起により一定ストロークの上下運動を行なって、挿入されるパイプ素材に打撃を加えて絞り加工を行なう加工法である。   For example, in rotary swaging, a pair or a plurality of dies and a backer incorporated in a main shaft in the machine perform a rotational motion, and a vertical stroke of a fixed stroke is performed by a peripheral roller and a protrusion on the backer, and then inserted. This is a processing method in which a pipe material is blown to perform drawing.

また、プレス加工は、パイプ素材をダイスに軸方向に押し込んで絞り加工を行なう加工法である。上記の塑性加工は、パイプ素材の軸方向全域に対して行っても良いし、軸方向両側部に対してのみ部分的に行なっても良い。   The press working is a working method in which a pipe material is pressed into a die in the axial direction to perform drawing. The plastic working may be performed on the entire axial direction of the pipe material, or may be performed partially only on both sides in the axial direction.

前者の場合、塑性加工後の中空状シャフト素材は、軸方向中間部の大径部と軸方向両側部の小径部において、塑性加工に伴う加工硬化と縮径による増肉が認められる。後者の場合、塑性加工後の中空状シャフト素材は、軸方向両側部の小径部において、塑性加工に伴う加工硬化と縮径による増肉が認められるが、軸方向中間部の大径部には、これらの現象は認められない。   In the former case, the hollow shaft material after plastic working is recognized to have increased thickness due to work hardening and shrinkage due to plastic working in the large diameter portion at the axial intermediate portion and the small diameter portions at both axial side portions. In the latter case, the hollow shaft material after plastic processing is recognized to have increased thickness due to work hardening and shrinkage due to plastic processing at the small diameter parts on both sides in the axial direction. These phenomena are not recognized.

あるいは、塑性加工として、パイプ素材の軸方向中間部を内周側から加圧して拡径させる加工法を採用することもできる。この場合、塑性加工後の中空状シャフト素材は、軸方向中間部の大径部において、塑性加工に伴う加工硬化と拡径による減肉が認められる。上記の機械加工は、例えば、小径部の端部の連結部に、継手との連結に供される歯型（スプラインやセレーション等）を転造やプレス加工等の手段によって加工するものである。この歯型は、両端部の連結部にそれぞれ形成しても良いし、一端部又は他端部の連結部にのみ形成しても良い。また、ブーツ固定部は、例えば、小径部の大径部側の外周面に旋削加工や転動加工等の手段によって加工することができる。小径部の最小径部は、平滑な外周面形状を呈し、通常は均一外径になっている。   Alternatively, as the plastic working, it is possible to employ a processing method in which the axially intermediate portion of the pipe material is pressurized from the inner peripheral side to expand the diameter. In this case, in the hollow shaft material after plastic processing, thinning due to work hardening and diameter expansion associated with plastic processing is recognized in the large diameter portion in the intermediate portion in the axial direction. In the above machining, for example, a tooth mold (spline, serration, etc.) used for connection with a joint is processed by means such as rolling or pressing at the connecting portion at the end of the small diameter portion. This tooth shape may be formed at the connecting portions at both ends, or may be formed only at the connecting portion at one end or the other end. Moreover, the boot fixing part can be machined by means such as turning or rolling on the outer peripheral surface of the small diameter part on the large diameter part side. The minimum diameter portion of the small diameter portion has a smooth outer peripheral surface shape, and usually has a uniform outer diameter.

上記のパイプ素材の材質としては、例えば、ＳＴＫＭやＳＴＡＭ等の機械構造用炭素鋼、または、それらをベースに加工性や焼入れ性等の改善のために合金元素を添加した合金鋼を用いることができる。   As the material of the above-mentioned pipe material, for example, carbon steel for mechanical structure such as STKM or STAM, or alloy steel to which an alloy element is added for improving workability, hardenability and the like based on them is used. it can.

上記の焼入れ処理の種類は特に限定されないが、パイプ素材の材質や動力伝達シャフトに要求される特性等を考慮すると、硬化層の範囲や深さを自由に選択でき、また、表面に残留圧縮応力が生成されることによる耐疲れ疲労性の改善等の点から、高周波誘導加熱方式を採用するのが好ましい。また、上記の焼戻し処理としては、局部的な焼戻し処理が可能な高周波誘導加熱方式を採用するのが好ましい。   The type of quenching treatment is not particularly limited, but considering the material of the pipe material and the characteristics required for the power transmission shaft, the range and depth of the hardened layer can be freely selected, and the residual compressive stress can be applied to the surface. It is preferable to employ a high frequency induction heating method from the viewpoint of improving fatigue fatigue resistance due to the formation of. Moreover, as said tempering process, it is preferable to employ | adopt the high frequency induction heating system in which a local tempering process is possible.

また、中空状動力伝達シャフトの材質としては、０．２〜０．４ｗｔ％の炭素を含有する鋼材を用いるのが好ましい。０．２〜０．４ｗｔ％の炭素を含有する鋼材は、焼入れを行い硬化させた後でも十分な靭性を有するため、最小径部に焼戻しを行なわず、焼入れのまま残しても、焼割れ等の心配はない。   Moreover, as a material of the hollow power transmission shaft, it is preferable to use a steel material containing 0.2 to 0.4 wt% carbon. The steel material containing 0.2 to 0.4 wt% carbon has sufficient toughness even after being hardened and hardened. There is no worry.

本発明によれば、静的強度の最弱部となる最小径部は、焼戻し処理が施されず、焼入れ状態のまま残されているので、必要な硬度が確保され、静的捩り強度等の静的強度が確保される。また、動的強度の最弱部となる連結部は、局部的に焼戻し処理が施されているので、焼入れ後の不安定な組織状態が改善され、焼割れ、置き割れ、経年変化の心配が解消されると同時に、必要な靭性が確保され、捩り疲労強度等の動的強度が確保される。さらに、ブーツ固定部に対しても局部的に焼戻し処理を施することにより、焼入れ後の不安定な組織状態が改善され、焼割れ、置き割れ、経年変化の心配が解消される。その結果、中空状動力伝達シャフトとしての強度アップと品質の安定が図られる。   According to the present invention, the minimum diameter portion which is the weakest portion of static strength is not subjected to tempering treatment and is left in the quenched state, so that necessary hardness is ensured and static torsional strength, etc. Static strength is ensured. In addition, the linking part, which is the weakest part of dynamic strength, is locally tempered, so the unstable structure after quenching is improved, and there is a risk of tempering cracks, cracks, and secular changes. At the same time, necessary toughness is ensured and dynamic strength such as torsional fatigue strength is ensured. Further, by locally tempering the boot fixing part, the unstable structure after quenching is improved, and the fear of tempering cracks, cracking, and secular change is eliminated. As a result, the strength and quality of the hollow power transmission shaft can be improved.

以下、本発明の実施形態を図面に従って説明する。   Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１は、中空状の動力伝達シャフト１と、動力伝達シャフト１の一端部に連結された摺動型等速自在継手２と、動力伝達シャフト１の他端部に連結された固定型等速自在継手３とを備えた自動車の動力伝達機構を示している。この実施形態の動力伝達機構において、摺動型等速自在継手２は減速装置（ディファレンシャル）に連結され、固定型等速自在継手３は駆動輪側に連結される。動力伝達シャフト１の一端部は摺動型等速自在継手２のトリポード部材２ａにスプライン連結され、摺動型等速自在継手２の外輪２ｂの端部外周と動力伝達シャフト１の外周にブーツ２ｃがそれぞれ固定されている。   FIG. 1 shows a hollow power transmission shaft 1, a sliding type constant velocity universal joint 2 connected to one end of the power transmission shaft 1, and a fixed type constant speed connected to the other end of the power transmission shaft 1. The power transmission mechanism of the motor vehicle provided with the universal joint 3 is shown. In the power transmission mechanism of this embodiment, the sliding type constant velocity universal joint 2 is connected to a reduction gear (differential), and the fixed type constant velocity universal joint 3 is connected to the drive wheel side. One end of the power transmission shaft 1 is splined to a tripod member 2a of the sliding type constant velocity universal joint 2, and a boot 2c is provided on the outer periphery of the outer ring 2b of the sliding type constant velocity universal joint 2 and the outer periphery of the power transmission shaft 1. Are fixed respectively.

また、動力伝達シャフト１の他端部は固定型等速自在継手３の内輪３ａにスプライン連結され、固定型等速自在継手３の外輪３ｂの端部外周と動力伝達シャフト１の外周にブーツ３ｃがそれぞれ固定されている。尚、同図には、摺動型等速自在継手２としてトリポード型等速自在継手が例示され、固定型等速自在継手３としてバーフィールド型等速自在継手が例示されているが、他の型式の等速自在継手が用いられる場合もある。   The other end of the power transmission shaft 1 is splined to the inner ring 3 a of the fixed type constant velocity universal joint 3, and a boot 3 c is provided on the outer circumference of the outer ring 3 b of the fixed type constant velocity universal joint 3 and the outer circumference of the power transmission shaft 1. Are fixed respectively. In the drawing, a tripod type constant velocity universal joint is illustrated as the sliding type constant velocity universal joint 2, and a barfield type constant velocity universal joint is illustrated as the fixed type constant velocity universal joint 3. Some types of constant velocity universal joints may be used.

図２は、動力伝達シャフト（ドライブシャフト）１を示している。この動力伝達シャフト１は、軸方向の全域に亘って中空状をなし、軸方向中間部に大径部１ａ、大径部１ａよりも軸方向両側部にそれぞれ小径部１ｂを有している。大径部１ａと小径部１ｂとは、軸端側に向かって漸次縮径したテーパ部１ｃを介して連続している。   FIG. 2 shows a power transmission shaft (drive shaft) 1. The power transmission shaft 1 is hollow over the entire region in the axial direction, and has a large-diameter portion 1a at an axial intermediate portion and small-diameter portions 1b at both axial sides of the large-diameter portion 1a. The large-diameter portion 1a and the small-diameter portion 1b are continuous via a tapered portion 1c that is gradually reduced in diameter toward the shaft end side.

小径部１ｂは、等速自在継手（２、３）との連結に供される端部側の連結部１ｄと、ブーツ（２ｃ、３ｃ）が固定される軸方向中間部側のブーツ固定部１ｅと、連結部１ｄとブーツ固定部１ｅとの間の最小径部１ｆとを有している。   The small-diameter portion 1b includes an end-side connection portion 1d used for connection with the constant velocity universal joints (2, 3), and an axial intermediate portion-side boot fixing portion 1e to which the boots (2c, 3c) are fixed. And a minimum diameter portion 1f between the connecting portion 1d and the boot fixing portion 1e.

連結部１ｄには、等速自在継手（２、３）にスプライン連結されるスプライン１ｄ１と、等速自在継手（２、３）に対する軸方向抜け止め用の止め輪を装着するための止め輪溝１ｄ２が加工されている。   A retaining ring groove for attaching a spline 1d1 splined to the constant velocity universal joints (2, 3) and a retaining ring for axially retaining the constant velocity universal joints (2, 3) to the coupling portion 1d. 1d2 is processed.

ブーツ固定部１ｅには、ブーツ（２ｃ、３ｃ）の小径端部の内周を嵌合するためのブーツ固定溝１ｅ１が加工されている。   The boot fixing portion 1e is processed with a boot fixing groove 1e1 for fitting the inner periphery of the small diameter end portion of the boot (2c, 3c).

この実施形態において、最小径部１ｆは、内径及び外径が軸方向にほぼ一定であり、軸方向にほぼ均一な形状を有している。   In this embodiment, the minimum diameter portion 1f has an inner diameter and an outer diameter that are substantially constant in the axial direction and has a substantially uniform shape in the axial direction.

この動力伝達シャフト１は、軸方向のほぼ全域Ｌに亘って、熱処理による硬化層Ｓを有している。軸方向域Ｌにおいて、硬化層Ｓは、外周表面１ｇから所定深さｈ０の領域に形成され、硬化層Ｓから内周表面１ｉに至る領域は焼入れ処理により硬化していない未硬化層Ｓ０になっている。尚、外周表面１ｇから内周表面１ｉに至る全肉厚領域に硬化層Ｓが形成されるようにしても良い。   The power transmission shaft 1 has a hardened layer S formed by heat treatment over substantially the entire region L in the axial direction. In the axial region L, the hardened layer S is formed in a region having a predetermined depth h0 from the outer peripheral surface 1g, and a region from the hardened layer S to the inner peripheral surface 1i becomes an uncured layer S0 that has not been hardened by the quenching process. ing. The hardened layer S may be formed in the entire thickness region from the outer peripheral surface 1g to the inner peripheral surface 1i.

この実施形態において、硬化層Ｓは、動力伝達シャフト１の軸方向のほぼ全域Ｌに亘って高周波誘導加熱による焼入れを行い、その後、小径部１ｂの連結部１ｄとブーツ固定部１ｅに高周波誘導加熱による局部的な焼戻しを行なって形成したものである。図２において、硬化層Ｓのうち、焼戻しが行なわれた領域をＳＢ（図２で××線を付して示している）で表している。   In this embodiment, the hardened layer S is quenched by high-frequency induction heating over almost the entire region L in the axial direction of the power transmission shaft 1, and then the high-frequency induction heating is applied to the connecting portion 1d of the small diameter portion 1b and the boot fixing portion 1e. It was formed by performing local tempering. In FIG. 2, the tempered region of the hardened layer S is represented by SB (shown with an xx line in FIG. 2).

上記構成の動力伝達シャフト１は、例えば、つぎのような態様で製造することができる。まず、機械構造用炭素鋼管（ＳＴＫＭ）等のパイプ素材に軸方向全域に亘ってロータリースウェージング加工を施して、軸方向中間部に大径部１ａ、軸方向両側部に小径部１ｂを有する中空状シャフト素材１'を成形する。   The power transmission shaft 1 having the above configuration can be manufactured, for example, in the following manner. First, a rotary swaging process is applied to a pipe material such as a carbon steel pipe for machine structure (STKM) over the entire axial direction, and a hollow having a large-diameter portion 1a at an axial middle portion and small-diameter portions 1b at both axial sides. The shaft material 1 ′ is formed.

前記機械構造用炭素鋼管としては、Ｃが０．２０ｗｔ％以上で０．４ｗｔ％以下、Ｓｉが０．０５ｗｔ％以上で０．３５ｗｔ％以下、Ｍｎが１．０ｗｔ％以上で２．０ｗｔ％以下、Ａｌが０．０５ｗｔ％以下、Ｓが０．０１ｗｔ％以下で含有し、残部がＦｅおよび不可避不純物を有する鋼材により形成されているものが望ましい。   As the carbon steel pipe for mechanical structure, C is 0.20 wt% or more and 0.4 wt% or less, Si is 0.05 wt% or more and 0.35 wt% or less, and Mn is 1.0 wt% or more and 2.0 wt% or less. It is desirable that Al is contained at 0.05 wt% or less, S is contained at 0.01 wt% or less, and the balance is formed of a steel material having Fe and inevitable impurities.

このようにして成形された中空状シャフト素材１'には、軸方向全域に亘って、ロータリースウェージング加工による加工硬化と縮径による増肉が認められる。そして、この中空状シャフト素材１'の小径部１ｂの端部に転造加工やプレス加工等によってスプライン１ｄ１を成形して連結部１ｄを形成すると共に、連結部１ｄに転造加工や切削加工等によって止め輪溝１ｄ２を形成する。また、ブーツ固定部１ｅとなる部位に転造加工や切削加工等によってブーツ固定溝１ｅ１を形成する。   In the hollow shaft material 1 ′ thus formed, work hardening by rotary swaging and thickening due to reduced diameter are recognized over the entire axial direction. Then, the spline 1d1 is formed by rolling or pressing at the end of the small diameter portion 1b of the hollow shaft material 1 ′ to form the connecting portion 1d, and the connecting portion 1d is subjected to rolling or cutting. Thus, the retaining ring groove 1d2 is formed. Further, a boot fixing groove 1e1 is formed by rolling or cutting at a portion to be the boot fixing portion 1e.

その後、図３に示すように、中空状シャフト素材１'の外周表面１ｇの側に、例えば移動式の高周波誘導加熱コイル４を外装し、高周波誘導加熱コイル４に所定周波数の高周波電流を通じつつ、これを軸方向に移動させて、外周表面１ｇの側から軸方向域Ｌに対して高周波焼入れを行なう。この高周波焼入れは、定置式焼入れ方式であってもよい。その際、比較的厚肉の小径部１ｂに対しては、高周波誘導加熱コイル４に通じる高周波電流の周波数を相対的に低くし、比較手薄肉の大径部１ａに対しては、高周波誘導加熱コイル４に通じる高周波電流の周波数を相対的に高くして、焼入率を変更してもよい。
そして、上記の高周波焼入れが終了した後、図３と同様の移動式の高周波誘導加熱コイル４を用いて、連結部１ｄとブーツ固定部１ｅに対して局部的な焼戻しを行なう。 After that, as shown in FIG. 3, for example, a mobile high-frequency induction heating coil 4 is sheathed on the outer peripheral surface 1 g side of the hollow shaft material 1 ′, and a high-frequency current having a predetermined frequency is passed through the high-frequency induction heating coil 4. This is moved in the axial direction, and induction hardening is performed on the axial region L from the outer peripheral surface 1g side. This induction hardening may be a stationary quenching method. At that time, the frequency of the high-frequency current leading to the high-frequency induction heating coil 4 is relatively lowered for the relatively thick small-diameter portion 1b, and the high-frequency induction heating is performed for the comparatively thin large-diameter portion 1a. The quenching rate may be changed by relatively increasing the frequency of the high-frequency current leading to the coil 4.
And after said induction hardening is complete | finished, local tempering is performed with respect to the connection part 1d and the boot fixing | fixed part 1e using the moving high frequency induction heating coil 4 similar to FIG.

材質ＳＴＫＭ−１５相当材で、最小径部１ｆの外形寸法φ２４ｍｍ、肉厚６ｍｍのパイプ材を用いて高周波誘導加熱焼入にて全硬化させた場合の硬度と、その後焼戻しを行った場合の硬度を測定した。その硬度分布を図４に示す。図４に示す結果から、焼入れのみの行なったパイプ材では表面硬度がＨＲＣ５８程度であったのに対して、焼戻しを行なったパイプ材では表面硬度がＨＲＣ５５程度となり、焼戻しにより表面硬度がＨＲＣで約３ポイント低下することが確認された。そして、両パイプ材について静的捩り強度を測定したところ、図５に示すように、焼戻しを行なったパイプ材の静的捩り強度を１００として、焼入れのみの行なったパイプ材では静的捩り強度が１０７となり、高い静的捩り強度が得られることが分かった。   Hardness when fully cured by high-frequency induction heating and quenching using a pipe material with an outer diameter of φ24 mm and a wall thickness of 6 mm with a minimum diameter portion 1f of material STKM-15 equivalent and hardness after tempering Was measured. The hardness distribution is shown in FIG. From the results shown in FIG. 4, the pipe material subjected only to quenching had a surface hardness of about HRC58, whereas the pipe material subjected to tempering had a surface hardness of about HRC55, and the surface hardness by tempering was about HRC. It was confirmed that it was reduced by 3 points. And when static torsional strength was measured about both pipe materials, as shown in FIG. 5, the static torsional strength of the pipe material which tempered only was made into 100, and static torsional strength of the pipe material which only tempered was shown. It was found that a high static torsional strength was obtained.

自動車の動力伝達機構を示す一部切欠け断面図である。It is a partially cutaway sectional view showing a power transmission mechanism of an automobile. 実施形態に係る動力伝達シャフトを示す一部断面図である。It is a partial sectional view showing a power transmission shaft concerning an embodiment. 中空状シャフト素材を示す断面図である。It is sectional drawing which shows a hollow shaft raw material. 硬度分布を示すグラフである。It is a graph which shows hardness distribution. 静捩り強度を示すグラフである。It is a graph which shows static torsion strength.

符号の説明Explanation of symbols

１ 動力伝達シャフト
１ａ 大径部
１ｂ 小径部
１ｆ 平滑部
１ｉ 内周表面
１ｇ 外周表面
Ｓ 硬化層
Ｓ０ 未硬化層
ＳＢ 焼戻し層 DESCRIPTION OF SYMBOLS 1 Power transmission shaft 1a Large diameter part 1b Small diameter part 1f Smoothing part 1i Inner peripheral surface 1g Outer peripheral surface S Hardened layer S0 Unhardened layer SB Tempered layer

Claims (2)

軸方向中間部が大径部に形成されると共に、該大径部よりも軸方向両側部がそれぞれ小径部に形成され、該小径部は、継手が連結される端部の連結部と、ブーツが固定される大径部側のブーツ固定部と、前記連結部とブーツ固定部との間の最小径部とを有する中空状動力伝達シャフトにおいて、
前記大径部及び小径部に焼入処理を施した後、前記小径部の連結部とブーツ固定部のうち、少なくとも前記連結部に局部的に焼戻し処理を施したことを特徴とする中空状動力伝達シャフト。 An axial intermediate portion is formed as a large diameter portion, and both axial side portions are formed as small diameter portions from the large diameter portion, and the small diameter portion includes an end connecting portion to which a joint is connected and a boot. In a hollow power transmission shaft having a boot fixing part on the large diameter part side to which is fixed, and a minimum diameter part between the connecting part and the boot fixing part,
A hollow power characterized in that after the quenching process is performed on the large diameter part and the small diameter part, at least the coupling part is locally tempered among the coupling part of the small diameter part and the boot fixing part. Transmission shaft. ０．２〜０．４ｗｔ％の炭素を含有する鋼材で形成されていることを特徴とする請求項１に記載の中空状動力伝達シャフト。   2. The hollow power transmission shaft according to claim 1, wherein the hollow power transmission shaft is formed of a steel material containing 0.2 to 0.4 wt% of carbon.
JP2005071533A 2005-03-14 2005-03-14 Hollow power transmission shaft Withdrawn JP2006250332A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106640932A (en) * 2016-12-21 2017-05-10 中国燃气涡轮研究院 Welded hollow variable-diameter central transmission rod
CN112638689A (en) * 2019-02-27 2021-04-09 日立安斯泰莫株式会社 Pipe body for transmission shaft and transmission shaft

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106640932A (en) * 2016-12-21 2017-05-10 中国燃气涡轮研究院 Welded hollow variable-diameter central transmission rod
CN112638689A (en) * 2019-02-27 2021-04-09 日立安斯泰莫株式会社 Pipe body for transmission shaft and transmission shaft
CN112638689B (en) * 2019-02-27 2024-03-19 日立安斯泰莫株式会社 Tube for a drive shaft and drive shaft

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