JP2013018417A - Method of manufacturing impact absorbing steering shaft - Google Patents

Method of manufacturing impact absorbing steering shaft Download PDF

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JP2013018417A
JP2013018417A JP2011154499A JP2011154499A JP2013018417A JP 2013018417 A JP2013018417 A JP 2013018417A JP 2011154499 A JP2011154499 A JP 2011154499A JP 2011154499 A JP2011154499 A JP 2011154499A JP 2013018417 A JP2013018417 A JP 2013018417A
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shaft
tip
diameter portion
peripheral surface
small
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JP5545275B2 (en
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Hiromichi Komori
宏道 小森
Kiyoshi Sadakata
清 定方
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NSK Ltd
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NSK Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide an impact absorbing steering shaft that smoothly and relatively displaces an outer shaft and an inner shaft in an axial direction due to an impact load during a secondary collision, and to provide a manufacturing method thereof.SOLUTION: While the tip of a large-diameter part 16a of an inner shaft 13a is engaged with the tip of a small-diameter part 14 of an outer shaft 12a, an outer circumferential surface of the small-diameter part 14 is pressed radially inward to plastically deform both tips radially inward. Shafts 12a, 13a are relatively displaced in an axial direction to be close to each other. The amount of pressing radially inward the outer circumferential surface of the tip of the small-diameter part 14 is smaller in a part near the tip edge of the tip of the large-diameter part 16a than in a part near the center. In the relative displacement, seizure is prevented in a friction part between the tip edge of the large-diameter part 16a and the inner circumferential surface of the small-diameter part 14.

Description

この発明は、自動車のステアリング装置を構成する衝撃吸収式ステアリングシャフトの製造方法の改良に関する。具体的には、このステアリングシャフトを製造する際に、インナシャフトの先端縁とアウタシャフトの内周面との間にかじりが発生するのを防止して、前記ステアリングシャフトの製造コストの増大を抑えつつ、衝撃吸収性能を安定させられる製造方法を実現するものである。尚、本発明の対象となるステアリングシャフトには、ステアリングコラムの内側に支持されるものだけでなく、ステアリングコラムの前側に配置される中間シャフトも含む。   The present invention relates to an improvement in a manufacturing method of an impact absorption type steering shaft constituting an automobile steering device. Specifically, when manufacturing this steering shaft, the occurrence of galling between the inner edge of the inner shaft and the outer peripheral surface of the outer shaft is prevented, thereby suppressing an increase in the manufacturing cost of the steering shaft. On the other hand, a manufacturing method capable of stabilizing the shock absorbing performance is realized. Note that the steering shaft that is an object of the present invention includes not only a shaft supported on the inside of the steering column but also an intermediate shaft disposed on the front side of the steering column.

操舵輪（フォークリフト等の特殊車両を除き、通常は前輪）に舵角を付与する為のステアリング装置として、例えば図６に示す様な構造が、広く知られている。このステアリング装置は、車体１に支持された円筒状のステアリングコラム２の内径側にステアリングシャフト３を、回転可能に支持している。そして、このステアリングコラム２の後端開口よりも後方に突出した、前記ステアリングシャフト３の後端部分に、ステアリングホイール４を固定している。このステアリングホイール４を回転させると、この回転が、前記ステアリングシャフト３、自在継手５ａ、中間シャフト６、自在継手５ｂを介して、ステアリングギヤユニット７の入力軸８に伝達される。この入力軸８が回転すると、このステアリングギヤユニット７の両側に配置された１対のタイロッド９、９が押し引きされて左右１対の操舵輪に、前記ステアリングホイール４の操作量に応じた舵角を付与する。尚、図６に示した構造の場合、このステアリングホイール４の前後位置の調節を可能にすべく、前記ステアリングコラム２及び前記ステアリングシャフト３として、伸縮式のものを使用している。又、上述の様なステアリング装置に、電気モータ１０を補助動力源として組み込んだ電動式パワーステアリング装置も、近年普及している。   For example, a structure as shown in FIG. 6 is widely known as a steering device for giving a steering angle to a steered wheel (usually a front wheel except a special vehicle such as a forklift). In this steering device, a steering shaft 3 is rotatably supported on the inner diameter side of a cylindrical steering column 2 supported by a vehicle body 1. A steering wheel 4 is fixed to the rear end portion of the steering shaft 3 protruding rearward from the rear end opening of the steering column 2. When the steering wheel 4 is rotated, this rotation is transmitted to the input shaft 8 of the steering gear unit 7 via the steering shaft 3, the universal joint 5a, the intermediate shaft 6, and the universal joint 5b. When the input shaft 8 rotates, a pair of tie rods 9, 9 arranged on both sides of the steering gear unit 7 are pushed and pulled, and a steering wheel according to the operation amount of the steering wheel 4 is turned to a pair of left and right steering wheels. Give a corner. In the case of the structure shown in FIG. 6, telescopic type is used as the steering column 2 and the steering shaft 3 in order to enable adjustment of the front-rear position of the steering wheel 4. In addition, in recent years, an electric power steering apparatus in which the electric motor 10 is incorporated as an auxiliary power source in the steering apparatus as described above has also become widespread.

前記ステアリングコラム２及び前記ステアリングシャフト３は、衝突事故の際に、衝撃エネルギを吸収しつつ、ステアリングホイール４を前方に変位させる構造としている。即ち、衝突事故の際には、自動車が他の自動車等にぶつかる一次衝突に続いて、運転者の身体がステアリングホイール４に衝突する二次衝突が発生する。この二次衝突の際に、運転者の身体に加わる衝撃を緩和して、運転者の保護を図る為に、前記ステアリングホイール４を支持したステアリングシャフト３を車体１に対して、二次衝突に伴う前方への衝撃荷重により前方に変位可能に支持する必要がある。この為に、前記ステアリングコラム２は、二次衝突の衝撃荷重により、アウタコラム１１がこのステアリングコラム２の全長を、前記ステアリングシャフト３は、アウタシャフト１２がこのステアリングシャフト３の全長を、それぞれ縮めながら前方に変位する事で、前記ステアリングホイール４に衝突した運転者の身体に大きな衝撃が加わる事を防止する。
上述の様な伸縮式のステアリングコラムを構成するアウタコラム及びインナコラム、並びに、ステアリングシャフトを構成するアウタシャフト及びインナシャフトの前後位置は、図示の構造とは逆であっても良い。上述の様な伸縮式のステアリングシャフトを製造する為の技術として、例えば特許文献１〜２に記載の技術がある。 The steering column 2 and the steering shaft 3 are configured to displace the steering wheel 4 while absorbing impact energy in the event of a collision. That is, in the event of a collision accident, a secondary collision in which the driver's body collides with the steering wheel 4 occurs following a primary collision in which the automobile collides with another automobile or the like. In order to alleviate the impact applied to the driver's body during the secondary collision and to protect the driver, the steering shaft 3 supporting the steering wheel 4 is subjected to the secondary collision with respect to the vehicle body 1. It is necessary to support it so that it can be displaced forward by a forward impact load. For this reason, the steering column 2 is contracted by the impact load of the secondary collision, the outer column 11 is shortened by the entire length of the steering column 2, and the steering shaft 3 is contracted by the outer shaft 12 by the total length of the steering shaft 3. However, a large impact is prevented from being applied to the driver's body colliding with the steering wheel 4 by being displaced forward.
The outer column and the inner column that constitute the telescopic steering column as described above, and the front and rear positions of the outer shaft and the inner shaft that constitute the steering shaft may be opposite to the illustrated structure. As a technique for manufacturing the telescopic steering shaft as described above, there are techniques described in Patent Documents 1 and 2, for example.

図７〜１０は、このうちの特許文献１に記載されている、衝撃吸収式のステアリングシャフト及びその製造方法の従来例を示している。ステアリングシャフト３ａは、アウタシャフト１２ａとインナシャフト１３とを軸方向に相対変位可能に係合させ、二次衝突時に、軸方向に加わる衝撃荷重により全長が縮まる様に構成している。
前記アウタシャフト１２ａは、全体を円管状とし、一端部（図７〜８の左端部）に絞り加工を施す事で、この一端部に小径部１４を形成している。この小径部１４の内周面には、雌セレーション１５を形成している。又、前記インナシャフト１３も、全体を円管状とし、一端部（図７〜８の右端部）を押し拡げる事で、この一端部に大径部１６を形成している。この大径部１６の外周面には、前記雌セレーション１５と係合する雄セレーション１７を形成している。 7 to 10 show a conventional example of an impact absorbing steering shaft and a manufacturing method thereof described in Patent Document 1 among them. The steering shaft 3a is configured such that the outer shaft 12a and the inner shaft 13 are engaged with each other so as to be relatively displaceable in the axial direction, and the total length is shortened by an impact load applied in the axial direction at the time of a secondary collision.
The outer shaft 12a has a circular tube shape as a whole, and a small diameter portion 14 is formed at one end portion by drawing one end portion (left end portion in FIGS. 7 to 8). A female serration 15 is formed on the inner peripheral surface of the small diameter portion 14. The inner shaft 13 is also formed in a circular tube shape as a whole, and a large-diameter portion 16 is formed at one end by expanding one end (the right end in FIGS. 7 to 8). A male serration 17 that engages with the female serration 15 is formed on the outer peripheral surface of the large diameter portion 16.

この様なアウタシャフト１２ａとインナシャフト１３とを組み合わせて、図７に示す様なステアリングシャフト３ａを製造する場合には、先ず、図８に示す様に、前記雌セレーション１５と前記雄セレーション１７とを、前記小径部１４の先端部（図８の左端部）と前記大径部１６の先端部（図８の右端部）とで互いに係合させる。
そして、前記両セレーション１５、１７同士を互いに係合させた状態のまま、前記小径部１４の先端部の外周面を径方向内方に押圧する。即ち、この小径部１４の先端部及び前記大径部１６の先端部の周囲に１対の押圧片１８、１８を配置し、これら両押圧片１８、１８を互いに近づけ合う事で、前記小径部１４の先端部の外周面を強く押圧する。これら両押圧片１８、１８の内側面でこの小径部１４の先端部の外周面と当接する部分には、この外周面に当接する部分の断面形状が円弧状である、凹部１９、１９を形成している。 When the steering shaft 3a as shown in FIG. 7 is manufactured by combining such an outer shaft 12a and the inner shaft 13, first, as shown in FIG. 8, the female serration 15 and the male serration 17 Are engaged with each other at the distal end portion (left end portion in FIG. 8) of the small diameter portion 14 and the distal end portion (right end portion in FIG. 8) of the large diameter portion 16.
And the outer peripheral surface of the front-end | tip part of the said small diameter part 14 is pressed to radial direction inward with the said both serrations 15 and 17 being mutually engaged. That is, a pair of pressing pieces 18, 18 are arranged around the distal end portion of the small diameter portion 14 and the distal end portion of the large diameter portion 16, and the two small pressing portions 18, 18 are brought close to each other, whereby the small diameter portion 14 strongly presses the outer peripheral surface of the tip portion. On the inner side surfaces of these pressing pieces 18, 18 are formed recesses 19, 19 in which the cross-sectional shape of the portion contacting the outer peripheral surface is arcuate in the portion contacting the outer peripheral surface of the tip of the small diameter portion 14 doing.

図９に示す様に、これら両凹部１９、１９を前記小径部１４の先端部の外周面に軽く当接させた状態で、前記両押圧片１８、１８の端面同士の間に、厚さがｔの隙間２０、２０が形成される。この状態から、これら両押圧片１８、１８を、図示しない押圧装置により、互いに近づく方向に強く押圧する。そして、図１０に示す様に、前記両隙間２０、２０の厚さが０となるまで、前記両押圧片１８、１８同士を互いに近づけ、前記小径部１４の先端部の断面形状を、図１０に示す様な楕円形に塑性変形させる。同時に、この小径部１４の先端部に挿入された大径部１６の先端部も、前記両セレーション１５、１７を介して押圧し、この大径部１６の先端部の断面形状も、図１０に示す様な楕円形に塑性変形させる。   As shown in FIG. 9, the thickness between the end faces of the two pressing pieces 18, 18 with both the recesses 19, 19 being in light contact with the outer peripheral surface of the distal end portion of the small diameter portion 14. T gaps 20 and 20 are formed. From this state, both the pressing pieces 18, 18 are strongly pressed in a direction approaching each other by a pressing device (not shown). Then, as shown in FIG. 10, the pressing pieces 18 and 18 are brought close to each other until the thickness of the gaps 20 and 20 becomes 0, and the cross-sectional shape of the distal end portion of the small diameter portion 14 is shown in FIG. It is plastically deformed into an oval shape as shown in. At the same time, the distal end portion of the large diameter portion 16 inserted into the distal end portion of the small diameter portion 14 is also pressed through the both serrations 15 and 17, and the sectional shape of the distal end portion of the large diameter portion 16 is also shown in FIG. Plastically deform into an elliptical shape as shown.

この様にして、前記小径部１４の先端部及び前記大径部１６の先端部を径方向内方に押圧し、これら両先端部の断面形状を楕円形に塑性変形させたならば、次いで、前記アウタシャフト１２ａと前記インナシャフト１３とを互いに近づく方向に軸方向に相対変位させる。即ち、前記両押圧片１８、１８から前記アウタシャフト１２ａと前記インナシャフト１３とを取り出した後、このアウタシャフト１２ａを図８の左方に、このインナシャフト１３を同じく右方に、相手部材に対して相対変位させる。そして、図７に示す様に、前記小径部１４の先端部を前記大径部１６の基端部に圧入嵌合すると共に、この大径部１６の先端部をこの小径部１４の基端部に圧入嵌合させる。前記両押圧片１８、１８により塑性変形させられていない、この小径部１４の中間部と前記大径部１６の中間部とは互いに緩く係合させる。
尚、上述の様な衝撃吸収式ステアリングシャフトを構成するインナシャフト１３は、アウタシャフト１２ａよりも外径が小さいので、強度を確保する為、Ｓ３５Ｃ等硬度の高い炭素鋼により形成する事が多い。或いは、ＳＴＫＭ１２Ｂ等の炭素鋼鋼管により形成する事もできるが、この場合は強度を確保する為、径方向の厚さを厚くする。 In this way, if the distal end portion of the small diameter portion 14 and the distal end portion of the large diameter portion 16 are pressed radially inward, and the cross-sectional shape of both the distal end portions is plastically deformed into an elliptical shape, then, The outer shaft 12a and the inner shaft 13 are relatively displaced in the axial direction so as to approach each other. That is, after the outer shaft 12a and the inner shaft 13 are taken out from both the pressing pieces 18, 18, the outer shaft 12a is placed on the left side of FIG. The relative displacement is made. As shown in FIG. 7, the distal end portion of the small diameter portion 14 is press-fitted into the proximal end portion of the large diameter portion 16, and the distal end portion of the large diameter portion 16 is replaced with the proximal end portion of the small diameter portion 14. Press-fit into. The intermediate portion of the small diameter portion 14 and the intermediate portion of the large diameter portion 16 that are not plastically deformed by the two pressing pieces 18 and 18 are loosely engaged with each other.
Since the inner shaft 13 constituting the shock absorbing steering shaft as described above has a smaller outer diameter than the outer shaft 12a, it is often formed of carbon steel having a high hardness such as S35C in order to ensure strength. Alternatively, it can be formed of a carbon steel pipe such as STKM12B. In this case, the radial thickness is increased in order to ensure strength.

以上の説明は、後端部分にステアリングホイール４（図６参照）を固定するステアリングシャフト３に就いて行ったが、ステアリング装置の前側部分に配置される中間シャフト６も同様にして、軸方向に収縮可能に構成する場合がある。この様な収縮式の中間シャフト６は、自動車が他の自動車等にぶつかる一次衝突の際に、この一次衝突に伴う衝撃荷重よりその全長を縮める事で、前記ステアリングホイール４が運転者側に突き上げられるのを防止し、運転者の保護を図る。又、前記中間シャフト６は、運転者の操作によって前記ステアリングホイール４から前記ステアリングシャフト３に付与されるトルクに加え、補助動力源である電動モータ１０の出力トルクを伝達する。この為、上述の様な衝撃吸収式ステアリングシャフトを、前記中間シャフト６に適用する場合、前記アウタシャフト１２ａとインナシャフト１３との係合部の保持力（嵌合強度）を大きくし、耐久性を高くする必要がある。この結果、前記大径部１６の先端部外周縁と、前記小径部１４の内周面との当接圧が高くなり、上述の様な衝撃吸収式ステアリングシャフトの製造方法を実施する場合に於いて、前記アウタシャフト１２ａとインナシャフト１３とを互いに近づく方向に軸方向に相対変位させる際に、前記大径部１６の先端部外周縁でかじりが発生し易い。即ち、この相対変位の際、断面形状が楕円形であるこの大径部１６の先端部外周縁の長径部分と、断面形状が円形である前記小径部１４の内周面とが強く擦れ合って、この先端部外周縁がこの小径部１４の内周面に食い込む（かじる）。この様にして発生したかじりを放置すると、衝突事故の際のエネルギ吸収性能が不安定になる可能性がある。そこでこのエネルギ吸収性能を安定させる為に、かじりにより生じた余肉部分（むしれ部分）を切削等により除去する手間が必要になる。又、かじりの程度によっては、完成後の衝撃吸収式ステアリングシャフトを、不良品として廃棄しなければならなくなり、加工の手間の増大や歩留りの悪化により、製造コストが上昇する為、改良が望まれる。特に、前記中間シャフト６の場合、前述した様に、保持力確保の為に嵌合部の当接圧を高くする為、改良する必要性が大きい。   Although the above description has been given with respect to the steering shaft 3 that fixes the steering wheel 4 (see FIG. 6) to the rear end portion, the intermediate shaft 6 disposed in the front portion of the steering device is similarly axially arranged. It may be configured to be shrinkable. Such a contraction-type intermediate shaft 6 has the steering wheel 4 pushed up to the driver side by reducing the overall length from the impact load accompanying the primary collision at the time of the primary collision when the automobile collides with another automobile or the like. To protect the driver. The intermediate shaft 6 transmits the output torque of the electric motor 10 as an auxiliary power source in addition to the torque applied from the steering wheel 4 to the steering shaft 3 by the operation of the driver. For this reason, when the shock absorbing steering shaft as described above is applied to the intermediate shaft 6, the holding force (fitting strength) of the engaging portion between the outer shaft 12a and the inner shaft 13 is increased, and the durability is improved. Need to be high. As a result, the contact pressure between the outer peripheral edge of the distal end portion of the large diameter portion 16 and the inner peripheral surface of the small diameter portion 14 is increased, and the impact absorbing steering shaft manufacturing method as described above is performed. When the outer shaft 12a and the inner shaft 13 are relatively displaced in the axial direction in a direction approaching each other, galling is likely to occur at the outer peripheral edge of the distal end portion of the large-diameter portion 16. That is, at the time of this relative displacement, the long diameter portion of the outer peripheral edge of the distal end portion of the large diameter portion 16 having an elliptical cross-sectional shape and the inner peripheral surface of the small diameter portion 14 having a circular cross sectional shape are strongly rubbed. The outer peripheral edge of the tip portion bites into the inner peripheral surface of the small diameter portion 14. If the galling generated in this way is left unattended, the energy absorption performance in the event of a collision may become unstable. Therefore, in order to stabilize the energy absorption performance, it is necessary to remove a surplus portion (peeling portion) generated by galling by cutting or the like. Also, depending on the degree of galling, the completed shock absorbing steering shaft must be discarded as a defective product, which increases manufacturing costs due to increased processing effort and yield, and improvements are desired. . In particular, in the case of the intermediate shaft 6, as described above, there is a great need for improvement in order to increase the contact pressure of the fitting portion in order to secure the holding force.

特許第３１６８８４１号公報Japanese Patent No. 3168841 特許第３７１６５９０号公報Japanese Patent No. 3716590

本発明は、上述の様な事情に鑑み、アウタシャフトとインナシャフトとを、二次衝突時に加わる衝撃荷重に伴い、これら両シャフト同士が軸方向に相対変位可能に結合して成る衝撃吸収式ステアリングシャフトの製造方法に於いて、前記インナシャフトの先端部外周縁と前記アウタシャフトの内周面との間にかじりが発生するのを防止し、加工の手間の増大や不良品の発生を抑えつつ、エネルギ吸収性能の安定した衝撃吸収式ステアリングシャフトを得られる様にして、製造コストの上昇を抑える事ができる製造方法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 is an impact-absorbing steering system in which an outer shaft and an inner shaft are coupled to each other so as to be capable of relative displacement in the axial direction in accordance with an impact load applied during a secondary collision. In the shaft manufacturing method, it is possible to prevent the occurrence of galling between the outer peripheral edge of the inner shaft and the inner peripheral surface of the outer shaft, while suppressing an increase in processing time and generation of defective products. The invention was invented to realize a manufacturing method capable of suppressing an increase in manufacturing cost so that an impact-absorbing steering shaft having stable energy absorption performance can be obtained.

本発明の衝撃吸収式ステアリングシャフトの製造方法は、アウタシャフトの先端部と、インナシャフトの先端部とを係合させた状態で、このアウタシャフトの先端部の外周面を径方向に（径方向反対位置を互いに近付く方向に）押圧し、このアウタシャフトの先端部及び前記インナシャフトの先端部を径方向に（押圧方向が短径でこれと直角方向が長径となる、断面楕円形に）塑性変形させる。次いで、前記両シャフト同士を互いに近づく方向に軸方向に相対変位させ、前記アウタシャフトの先端部を前記インナシャフトの中間部に、このインナシャフトの先端部をこのアウタシャフトの中間部に、それぞれ圧入嵌合させ、このアウタシャフトの先端部と中間部との間部分と、前記インナシャフトの先端部と中間部との間部分とを互いに緩く係合させる。
特に、本発明の衝撃吸収式ステアリングシャフトの製造方法に於いては、前記アウタシャフトの先端部の外周面を径方向内方に押圧する量を、前記インナシャフトの先端部の先端縁寄り部分で、同じく中間寄り部分よりも少なくする。 In the manufacturing method of the shock absorbing steering shaft of the present invention, the outer peripheral surface of the outer shaft tip portion is radially (radial direction) in a state in which the outer shaft tip portion and the inner shaft tip portion are engaged. Pressing the opposite positions toward each other), the tip of the outer shaft and the tip of the inner shaft are in the radial direction (in the shape of an elliptical section with the pressing direction being the short diameter and the direction perpendicular thereto being the long diameter) Deform. Next, the shafts are relatively displaced in the axial direction so as to approach each other, and the tip of the outer shaft is press-fitted into the middle of the inner shaft, and the tip of the inner shaft is press-fitted into the middle of the outer shaft. The portion between the tip portion and the intermediate portion of the outer shaft and the portion between the tip portion and the intermediate portion of the inner shaft are loosely engaged with each other.
In particular, in the shock absorbing steering shaft manufacturing method of the present invention, the amount of pressing the outer peripheral surface of the outer shaft tip portion inward in the radial direction is determined by the portion near the tip edge of the inner shaft tip portion. , Also less than the middle part.

上述の様に構成する、本発明の衝撃吸収式ステアリングシャフトの製造方法によれば、アウタシャフトの先端縁とインナシャフトの内周面との間にかじりが発生するのを防止し、加工の手間の増大や不良品の発生を抑えつつ、優れた衝撃エネルギ吸収性能を発揮できる衝撃吸収式ステアリングシャフトを組み立てて、前記ステアリングシャフトの製造コストの上昇を抑える事ができる。この理由は、前記アウタシャフトの先端部の外周面を径方向内方に押圧する量を、前記インナシャフトの先端部の先端縁寄り部分で、同じく中間寄り部分よりも少なくしている為、このインナシャフトの先端縁と前記アウタシャフトの内周面との間でかじりが発生するのを防止できるからである。即ち、このアウタシャフトの内周面と係合する前記インナシャフトの先端部のうち、先端縁寄り部分の押圧量は少ない為、この先端縁寄り部分の断面形状が円形から楕円形に変化する程度は少ない。要するに、押圧される部分が径方向に押し潰されるのに伴い、この部分から円周方向に９０度位相がずれた部分が径方向に拡げられる量が少なくなる。この結果、この円周方向に９０度位相がずれた部分と、前記アウタシャフトの内周面との当接圧を低くできる。この為、前記両シャフト同士を互いに近づく方向に軸方向に相対変位させる際に、前記インナシャフトの先端縁部分と前記アウタシャフトの内周面との間に作用する摩擦を小さく抑える事ができて、この先端縁部分がこの内周面に食い込む事を防止でき、前記かじりの発生を防止できる。前記先端縁部分よりも中間寄り部分は十分に変形するが、この中間寄り部分と前記アウタシャフトの内周面との擦れ合い部でかじりが発生する事は少ない。この結果、かじりの発生防止と、前記両シャフトの嵌合強度の確保とを両立させられる。   According to the shock absorbing type steering shaft manufacturing method of the present invention configured as described above, it is possible to prevent the occurrence of galling between the outer edge of the outer shaft and the inner peripheral surface of the inner shaft, and to reduce the processing effort. As a result, an increase in manufacturing cost of the steering shaft can be suppressed by assembling an impact absorbing steering shaft capable of exhibiting excellent impact energy absorbing performance while suppressing an increase in the number of defects and the occurrence of defective products. This is because the amount of pressing the outer peripheral surface of the tip of the outer shaft radially inward is less at the tip edge portion of the inner shaft tip than at the middle portion. This is because galling can be prevented between the tip edge of the inner shaft and the inner peripheral surface of the outer shaft. That is, of the tip portion of the inner shaft that engages with the inner peripheral surface of the outer shaft, the amount of pressing at the tip edge portion is small, so that the cross-sectional shape of the tip edge portion changes from a circle to an ellipse. There are few. In short, as the pressed portion is crushed in the radial direction, the amount of the portion whose phase is shifted by 90 degrees in the circumferential direction from this portion is reduced in the radial direction. As a result, the contact pressure between the portion whose phase is shifted by 90 degrees in the circumferential direction and the inner peripheral surface of the outer shaft can be reduced. For this reason, when the two shafts are relatively displaced in the axial direction in a direction approaching each other, the friction acting between the tip edge portion of the inner shaft and the inner peripheral surface of the outer shaft can be reduced. The tip edge portion can be prevented from biting into the inner peripheral surface, and the occurrence of the galling can be prevented. The intermediate portion is sufficiently deformed than the tip edge portion, but the occurrence of galling at the rubbing portion between the intermediate portion and the inner peripheral surface of the outer shaft is small. As a result, it is possible to achieve both prevention of galling and securing of the fitting strength of the two shafts.

本発明の実施の形態の第１例を示す、図８と同様の図。The figure similar to FIG. 8 which shows the 1st example of embodiment of this invention. 同じく、図１のＸ部拡大図。Similarly, the X section enlarged view of FIG. 本発明の実施の形態の第２例を示す、図１と同様の図。The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. 同じく第３例を示す、図１と同様の図。The figure similar to FIG. 1 which shows the 3rd example similarly. 同じく第４例を示す、図２と同様の図。The figure similar to FIG. 2 which shows the 4th example similarly. 従来から知られているステアリング装置の１例を、一部を切断した状態で示す側面図。The side view which shows one example of the steering device conventionally known in the state which cut | disconnected a part. 本発明の製造方法の対象となる衝撃吸収式ステアリングシャフトの、従来構造の１例を示す断面図。Sectional drawing which shows an example of the conventional structure of the shock absorption type steering shaft used as the object of the manufacturing method of this invention. 従来構造の製造時に、インナシャフトの先端部とアウタシャフトの先端部とを係合させた状態を示す断面図。Sectional drawing which shows the state which engaged the front-end | tip part of the inner shaft, and the front-end | tip part of the outer shaft at the time of manufacture of a conventional structure. 図８のＹ−Ｙ断面図。YY sectional drawing of FIG. １対の押圧片により、前記両先端部を径方向内方に塑性変形した状態で示す、図９と同様の図。FIG. 10 is a view similar to FIG. 9, showing a state where both the tip portions are plastically deformed radially inward by a pair of pressing pieces.

［実施の形態の第１例］
図１〜２は、全ての請求項に対応する、本発明の実施の形態の第１例を示している。尚、本例を含めて、本発明の衝撃吸収式ステアリングシャフトの製造方法の特徴は、インナシャフト１３ａの先端縁と、アウタシャフト１２ａの内周面との間でかじりが発生するのを防止し、加工の手間の増大や不良品の発生を抑えつつ、優れた衝撃エネルギ吸収性能を発揮できる衝撃吸収式ステアリングシャフトを組み立てて、製造コストの上昇を抑える点にある。その他の部分の構成及び作用は、前述の図７〜１０に示した従来の製造方法を含め、従来から知られている衝撃吸収式ステアリングシャフトの製造方法と同様であるから、同等部分に関する図示並びに説明は、省略若しくは簡略にし、以下、本例の特徴部分を中心に説明する。 [First example of embodiment]
1-2 show a first example of an embodiment of the invention corresponding to all claims. In addition, including the present example, the features of the shock absorbing steering shaft manufacturing method of the present invention prevent galling between the tip edge of the inner shaft 13a and the inner peripheral surface of the outer shaft 12a. In addition, an impact absorbing type steering shaft capable of exhibiting excellent impact energy absorbing performance can be assembled while suppressing an increase in processing time and generation of defective products, thereby suppressing an increase in manufacturing cost. Since the configuration and operation of the other parts are the same as those of the conventionally known shock absorbing type steering shaft manufacturing method including the conventional manufacturing method shown in FIGS. The description will be omitted or simplified, and the following description will focus on the features of this example.

本例の場合、先ず、図１に示す様に、前記インナシャフト１３ａの後端部に形成した大径部１６ａの先端部を、前記アウタシャフト１２ａの前端部に形成した小径部１４の先端部に係合させる。上述の様な大径部１６ａは、前述した従来構造の場合と同様に、円管状の前記インナシャフト１３ａの後端部を押し拡げる事により形成する。若しくはこのインナシャフト１３ａの前端部外周面に切削加工を施す事により形成しても良い。或いは、このインナシャフト１３ａを前記アウタシャフト１２ａの内径側に挿通可能であれば、前記大径部１６ａを設けず、前記インナシャフト１３ａの外径を軸方向全長に亙って同じとする事もできる。但し、この場合は、完成後のステアリングシャフト３ａ（図７参照）の収縮荷重が過大になるのを防止すべく、前記インナシャフト１３ａの外周面に軸方向全長に亙って雄セレーション１７を形成する。
又、前記小径部１４は、前述した従来構造の場合と同様に円管状である前記アウタシャフト１２ａの前端部に絞り加工を施す事により、若しくは後端部内周面に切削加工を施す事により形成する。或いは、前記インナシャフト１３ａを前記アウタシャフト１２ａの内径側に挿通可能であれば、前記小径部１４を設けず、このアウタシャフト１２ａの内径を軸方向全長に亙って同じとする事もできる。但し、この場合は、前記ステアリングシャフト３ａの収縮荷重が過大になるのを防止すべく、前記アウタシャフト１２ａの内周面に軸方向全長に亙って前記雄セレーション１７と係合する、雌セレーション１５を形成する。
図１〜２に示した本例の構造の場合、前記インナシャフト１３ａの後端部を押し拡げる事により前記大径部１６ａを、前記アウタシャフト１２ａの前端部に絞り加工を施す事により前記小径部１４を、それぞれ設けている。 In the case of this example, first, as shown in FIG. 1, the distal end portion of the small diameter portion 14 formed at the front end portion of the outer shaft 12a is replaced with the distal end portion of the large diameter portion 16a formed at the rear end portion of the inner shaft 13a. Engage with. The large-diameter portion 16a as described above is formed by expanding the rear end portion of the circular inner shaft 13a as in the case of the conventional structure described above. Alternatively, it may be formed by cutting the outer peripheral surface of the front end portion of the inner shaft 13a. Alternatively, if the inner shaft 13a can be inserted into the inner diameter side of the outer shaft 12a, the outer diameter of the inner shaft 13a may be the same over the entire axial length without providing the large diameter portion 16a. it can. However, in this case, male serrations 17 are formed on the outer peripheral surface of the inner shaft 13a over the entire length in the axial direction in order to prevent an excessive contraction load of the completed steering shaft 3a (see FIG. 7). To do.
The small-diameter portion 14 is formed by drawing the front end portion of the outer shaft 12a, which is tubular like the conventional structure, or by cutting the inner peripheral surface of the rear end portion. To do. Alternatively, if the inner shaft 13a can be inserted into the inner diameter side of the outer shaft 12a, the inner diameter of the outer shaft 12a can be made the same over the entire length in the axial direction without providing the small diameter portion 14. However, in this case, in order to prevent an excessive contraction load of the steering shaft 3a, a female serration that engages with the male serration 17 over the entire length in the axial direction on the inner peripheral surface of the outer shaft 12a. 15 is formed.
In the case of the structure of this example shown in FIGS. 1 and 2, the large-diameter portion 16a is formed by expanding the rear end portion of the inner shaft 13a, and the small-diameter portion is formed by drawing the front end portion of the outer shaft 12a. Each part 14 is provided.

そして、この小径部１４の先端部の外周面を１対の押圧片１８ａ、１８ａにより径方向内方に押圧し、前述した従来の製造方法の１例を示す図９→図１０の場合と同様に、ステアリングシャフト３ａ（図７参照）の中心軸に直交する仮想平面に関する断面形状が楕円形となる様に、前記小径部１４の先端部の外周面を径方向内方に押圧する。この時、前記両押圧片１８ａ、１８ａを押圧する押圧力を調整しても良い。即ち、これら両押圧片１８ａ、１８ａの端面同士の間の隙間２０、２０（図９参照）の厚さを、前記両先端部を押圧した状態で正の値とし（隙間２０、２０を残し）、これら両先端部の押圧量を調整する事もできる。又、前記両押圧片１８ａ、１８ａの内側面で前記小径部１４の先端部の外周面と当接する部分の形状は、前述した図９〜１０に示す様な断面が円弧状の凹部１９、１９に限らず、前記小径部１４の先端部の外周面の径方向反対位置を、互いに近づく方向に押圧できれば、平面や断面形状がＶ字形の面等とする事もできる。更に、断面円弧状とする場合でも、前記小径部１４の先端部外周面の曲率半径との大小関係は何れでも良い。何れにしても、本例の場合、前記両押圧片１８ａ、１８ａの軸方向両端縁に、断面形状が部分円弧状（Ｒ状）の面取り部２１ａ、２１ｂを設けている。これら両面取り部２１ａ、２１ｂは、前記大径部１６ａの先端縁側（図１〜２の右側）の面取り部２１ａの断面形状の曲率半径ｒ１を、前記小径部１４の先端縁側（図１〜２の左側）の面取り部２１ｂの断面形状の曲率半径ｒ２よりも大きく（ｒ１＞ｒ２）している。即ち、前記両先端部を径方向内方に押圧する量は、前記両押圧片１８ａ、１８ａの軸方向中間部で最も多く、前記小径部１４の先端縁寄り部分（図１〜２の左側）、前記大径部１６ａの先端縁寄り部分（図１〜２の右側）の順に少なくしている。前記両部１４、１６ａの先端部を径方向内方に押圧したならば、次いで、前記アウタシャフト１２ａと前記インナシャフト１３ａとを軸方向に相対変位させる。そして、前述の図７に示す様に、前記小径部１４の先端部を前記大径部１６ａの基端部に、この大径部１６ａの先端部にこの小径部１４の基端部を、それぞれ圧入嵌合させる。又、これら小径部１４の中間部と大径部１６ａの中間部とは、互いに緩く嵌合させる。 And the outer peripheral surface of the front-end | tip part of this small diameter part 14 is pressed radially inward by a pair of press pieces 18a and 18a, and it is the same as that of the case of FIG. 9-> 10 which shows an example of the conventional manufacturing method mentioned above. Further, the outer peripheral surface of the distal end portion of the small-diameter portion 14 is pressed radially inward so that the cross-sectional shape related to the virtual plane orthogonal to the central axis of the steering shaft 3a (see FIG. 7) is elliptical. At this time, the pressing force for pressing both the pressing pieces 18a, 18a may be adjusted. That is, the thicknesses of the gaps 20 and 20 (see FIG. 9) between the end faces of both the pressing pieces 18a and 18a are set to positive values in the state where both the tip portions are pressed (leaving the gaps 20 and 20). The pressing amount of both the tip portions can also be adjusted. The shape of the portion of the inner surface of the pressing pieces 18a, 18a that contacts the outer peripheral surface of the tip of the small-diameter portion 14 is a concave portion 19, 19 having a circular cross section as shown in FIGS. Not limited to this, as long as the radially opposite positions of the outer peripheral surface of the distal end portion of the small-diameter portion 14 can be pressed toward each other, the plane or the cross-sectional shape can be a V-shaped surface or the like. Furthermore, even when the cross-sectional arc shape is used, the magnitude relationship with the radius of curvature of the outer peripheral surface of the distal end portion of the small diameter portion 14 may be any. In any case, in the case of this example, chamfered portions 21a and 21b having a partially arcuate (R-shaped) cross-sectional shape are provided at both axial end edges of the pressing pieces 18a and 18a. These double-sided chamfer 21a, 21b, the curvature radius r 1 of the cross-sectional shape of the chamfered portion 21a at the tip edge of the large diameter portion 16a (right side in FIG. 1-2), the tip edge (Figure 1 of the small diameter portion 14 is larger (r 1> r 2) than the radius of curvature r 2 of the cross-sectional shape of the chamfered portion 21b of the second left). That is, the amount of pressing both the tip portions inward in the radial direction is the largest in the axial middle portion of the pressing pieces 18a, 18a, and the portion near the tip edge of the small diameter portion 14 (left side in FIGS. 1 and 2). , The portion closer to the tip edge of the large diameter portion 16a (the right side in FIGS. 1 and 2) is reduced in order. If the tip portions of both the portions 14 and 16a are pressed radially inward, then the outer shaft 12a and the inner shaft 13a are relatively displaced in the axial direction. Then, as shown in FIG. 7 described above, the distal end portion of the small diameter portion 14 is disposed at the proximal end portion of the large diameter portion 16a, and the proximal end portion of the small diameter portion 14 is disposed at the distal end portion of the large diameter portion 16a. Press fit. Further, the intermediate portion of the small diameter portion 14 and the intermediate portion of the large diameter portion 16a are loosely fitted to each other.

尚、本例の場合には、円管状のインナシャフト１３ａの先端部内周縁に、断面形状が部分円弧状（Ｒ状）の面取り部２２を設けている。この面取り部２２の基端部（小径側端部）は、前記両押圧片１８ａ、１８ａにより、前記両シャフト１２ａ、１３ａ同士を押圧する際に、これら両押圧片１８ａ、１８ａの軸方向中間部（これら両押圧片１８ａ、１８ａの厚さ範囲内）のうち、前記両面取り部２１ａ、２１ｂを形成した軸方向両端縁を除いた部分の径方向内方に位置させている。   In the case of this example, a chamfered portion 22 having a partially arcuate (R-shaped) cross-sectional shape is provided on the inner peripheral edge of the tip of the circular inner shaft 13a. The base end portion (small-diameter side end portion) of the chamfered portion 22 is an intermediate portion in the axial direction between the pressing pieces 18a and 18a when the pressing pieces 18a and 18a press the shafts 12a and 13a. Of the two pressing pieces 18a and 18a, within the thickness range, the two-sided chamfered portions 21a and 21b are positioned radially inward of the portion excluding both end edges in the axial direction.

上述の様に構成する本発明の衝撃吸収式ステアリングシャフトの製造方法によれば、前記インナシャフト１３ａの大径部１６ａの先端縁と前記アウタシャフト１２ａの小径部１４の内周面との間にかじりが発生するのを防止し、ステアリングシャフトの製造コストの上昇を抑えつつ、優れた衝撃エネルギ吸収性能を発揮できる衝撃吸収式ステアリングシャフトを組み立てる事ができる。この理由は、前記両押圧片１８ａ、１８ａの軸方向両端縁のうち、前記大径部１６ａの先端縁側（図１〜２の右側）に面取り部２１ａを設ける事で、前記両シャフト１２ａ、１３ａを径方向内方に押圧する際に、このアウタシャフト１２ａの内周面に形成した雌セレーション１５と、前記インナシャフト１３ａの外周面に形成した雄セレーション１７とを介し押圧される、前記大径部１６ａの先端部のうち、この大径部１６ａの先端縁寄り部分の押圧量を少なくしているからである。この押圧量を少なくしているので、この大径部１６ａの先端縁寄り部分のうち、前記小径部１４の先端部の外周面で前記両押圧片１８ａ、１８ａの凹部１９、１９（図９〜１０参照）により押圧される部分の径方向内方に位置する部分から円周方向に９０度位相がずれた部分の変形量（これら両径方向内方に位置する部分が径方向に押し潰されるのに伴い、径方向に拡げられる量）が少ない。この様に、前記９０度位相がずれた部分の変形量を少なく抑えている為、前記アウタシャフト１２ａと前記インナシャフト１３ａとを互いに近づく方向に軸方向に相対変位させる際に、前記大径部１６ａの先端部外周縁と前記小径部１４の内周面とが強く擦れ合う事がない。即ち、管状のアウタシャフト１２ａの内周面と係合する前記大径部１６ａの先端部の先端縁寄り部分のうち、前記円周方向に９０度位相がずれた部分の変形量は少なくなっており、前記大径部１６ａの先端縁部分と前記小径部１４の内周面との当接圧は低い。勿論、押圧された部分にスプリングバックにより生じる当接圧にしても、低く抑えられる。この為、前記両シャフト１２ａ、１３ａ同士を相対変位させる際に、前記大径部１６ａの先端縁部分と前記小径部１４の内周面との間に作用する摩擦力を小さく抑える事ができる。そして、この先端縁部分がこの内周面に食い込む事を防止でき、この内周面にかじりによる余肉部（むしれ）が発生するのを防止できる。   According to the manufacturing method of the shock absorbing steering shaft of the present invention configured as described above, between the leading edge of the large diameter portion 16a of the inner shaft 13a and the inner peripheral surface of the small diameter portion 14 of the outer shaft 12a. It is possible to assemble an impact-absorbing steering shaft that can exhibit excellent impact energy absorption performance while preventing galling and suppressing an increase in the manufacturing cost of the steering shaft. The reason for this is that by providing a chamfered portion 21a on the tip edge side (the right side in FIGS. 1 and 2) of the large-diameter portion 16a in both axial ends of the pressing pieces 18a and 18a, the shafts 12a and 13a are provided. Is pressed through the female serration 15 formed on the inner peripheral surface of the outer shaft 12a and the male serration 17 formed on the outer peripheral surface of the inner shaft 13a. This is because the pressing amount of the portion near the tip edge of the large diameter portion 16a is reduced in the tip portion of the portion 16a. Since the pressing amount is reduced, the concave portions 19 and 19 of the pressing pieces 18a and 18a on the outer peripheral surface of the distal end portion of the small diameter portion 14 in the portion near the distal end edge of the large diameter portion 16a (FIG. 9 to FIG. 9). 10), the amount of deformation of the portion whose phase is shifted by 90 degrees in the circumferential direction from the portion positioned radially inward of the portion pressed by the portion (the portions positioned inward in both the radial directions are crushed in the radial direction). (The amount that can be expanded in the radial direction) is small. As described above, since the amount of deformation of the portion where the phase is shifted by 90 degrees is suppressed, when the outer shaft 12a and the inner shaft 13a are relatively displaced in the axial direction toward each other, the large diameter portion The outer peripheral edge of the distal end portion of 16a and the inner peripheral surface of the small diameter portion 14 are not rubbed strongly. That is, the deformation amount of the portion near the tip edge of the tip portion of the large diameter portion 16a that engages with the inner peripheral surface of the tubular outer shaft 12a is reduced by 90 degrees in the circumferential direction. The contact pressure between the tip edge portion of the large diameter portion 16a and the inner peripheral surface of the small diameter portion 14 is low. Of course, even the contact pressure generated by the springback at the pressed portion can be kept low. For this reason, when the shafts 12a and 13a are relatively displaced, the frictional force acting between the tip edge portion of the large-diameter portion 16a and the inner peripheral surface of the small-diameter portion 14 can be reduced. And it can prevent that this front-end edge part bites into this internal peripheral surface, and can prevent that the surplus part (slipping) by a galling generate | occur | produces on this internal peripheral surface.

又、前記両押圧片１８ａ、１８ａの軸方向両端縁のうち、前記小径部１４の先端縁側（図１〜２の左側）に面取り部２１ｂを設ける事で、前記両シャフト１２ａ、１３ａを径方向内方に押圧する際に、前記小径部１４の先端部の先端縁寄り部分のうち、前記両凹部１９、１９により押圧される部分の押圧量を少なくしている。この為、これら両凹部１９、１９により押圧される部分が径方向内方に塑性変形される量（押し潰される量）を少なくしている。この結果、前記両シャフト１２ａ、１３ａ同士を互いに近づく方向に軸方向に相対変位させても、前記小径部１４の先端部内周縁と前記大径部１６ａの外周面とが強く擦れ合う事がない。即ち、前記インナシャフト１３ａの外周面と係合する前記小径部１４の先端部の先端縁部分のうち、前記両凹部１９、１９により押圧される部分の変形量は少なくなっており、前記小径部１４の先端縁部分と前記大径部１６ａの外周面との当接圧は低い。この為、前記両シャフト１２ａ、１３ａ同士を相対変位させる際に、前記小径部１４の先端縁部分と前記大径部１６ａの外周面との間に作用する摩擦を小さく抑える事ができる。そして、前記先端縁部分がこの外周面に食い込む事を防止でき、この外周面にかじりによる余肉部（むしれ）が発生するのを防止できる。前記両押圧片１８ａ、１８ａのうちで、前記各面取り部２１ａ、２１ｂ同士の間部分は、前記両シャフト１２ａ、１３ａの先端部同士の嵌合部を十分に強く押圧し、当該部分を十分に変形させて、嵌合部の面圧を十分に高くする。但し、この部分の面圧が高くなっても、前記両シャフト１２ａ、１３ａ同士を相対変位させる際に、かじりが発生する事はない。一方、前記面圧を高くする事で、前記両シャフト１２ａ、１３ａの嵌合強度を大きくして、完成後のエネルギ吸収式ステアリングシャフトの捩り剛性並びに曲げ剛性を十分に高くできる。   Further, by providing a chamfered portion 21b on the tip edge side (left side in FIGS. 1 and 2) of the small-diameter portion 14 in both axial ends of the pressing pieces 18a and 18a, the shafts 12a and 13a are radially arranged. When pressing inward, the pressing amount of the portion pressed by the both concave portions 19 and 19 in the portion near the tip edge of the tip portion of the small diameter portion 14 is reduced. For this reason, the amount of plastic deformation of the portions pressed by the concave portions 19 and 19 radially inward (amount of being crushed) is reduced. As a result, even if the shafts 12a and 13a are relatively displaced in the axial direction so as to approach each other, the inner peripheral edge of the distal end portion of the small diameter portion 14 and the outer peripheral surface of the large diameter portion 16a do not rub against each other. That is, of the tip edge portion of the tip portion of the small diameter portion 14 that engages with the outer peripheral surface of the inner shaft 13a, the amount of deformation of the portion pressed by the concave portions 19 and 19 is small, and the small diameter portion The contact pressure between the tip end edge portion 14 and the outer peripheral surface of the large diameter portion 16a is low. For this reason, when the shafts 12a and 13a are relatively displaced, the friction acting between the tip edge portion of the small diameter portion 14 and the outer peripheral surface of the large diameter portion 16a can be suppressed. And it can prevent that the said front-end | tip edge part bites into this outer peripheral surface, and can prevent that the surplus part (slipping) by a galling generate | occur | produces on this outer peripheral surface. Of the two pressing pieces 18a and 18a, the portion between the chamfered portions 21a and 21b sufficiently presses the fitting portion between the tip portions of the shafts 12a and 13a sufficiently, The surface pressure of the fitting portion is sufficiently increased by deforming. However, even if the surface pressure at this portion increases, no galling occurs when the shafts 12a and 13a are relatively displaced. On the other hand, by increasing the surface pressure, the fitting strength between the shafts 12a and 13a can be increased, and the torsional rigidity and bending rigidity of the completed energy absorbing steering shaft can be sufficiently increased.

又、本例の場合には、前記両面取り部２１ａ、２１ｂのうち、前記大径部１６ａの先端縁寄り部分に対応する面取り部２１ａの断面形状の曲率半径ｒ１を、前記小径部１４の先端縁寄り部分に対応する面取り部２１ｂの断面形状の曲率半径ｒ２よりも大きくしている。そして、前記大径部１６ａの先端縁寄り部分の押圧量を、前記小径部１４の先端縁寄り部分の押圧量よりも少なくしている。この様な構成により、前記大径部１６ａの先端縁部分と前記小径部１４の内周面との間に作用する摩擦力を、前記小径部１４の先端縁部分と前記大径部１６ａの外周面との間に作用する摩擦力よりも十分に小さくして、前記小径部１４の内周面部分でのかじり防止を有効に図れる。 Further, in the case of this example, the double-sided chamfer 21a, of the 21b, the curvature radius r 1 of the cross-sectional shape of the chamfered portion 21a corresponding to the leading edge portion close to the large diameter portion 16a, of the smaller-diameter portion 14 It is larger than the radius of curvature r 2 of the cross-sectional shape of the chamfered portion 21b corresponding to the leading edge portion close. The pressing amount of the portion near the leading edge of the large diameter portion 16a is made smaller than the pressing amount of the portion near the leading edge of the small diameter portion 14. With such a configuration, the frictional force acting between the tip edge portion of the large diameter portion 16a and the inner peripheral surface of the small diameter portion 14 is reduced to the outer periphery of the tip edge portion of the small diameter portion 14 and the large diameter portion 16a. It is possible to effectively prevent galling at the inner peripheral surface portion of the small-diameter portion 14 by sufficiently reducing the frictional force acting on the surface.

更に、本例の場合、円管状のインナシャフト１３ａの大径部１６ａの先端部内周縁にＲ状の面取り部２２を設け、この大径部１６ａの先端部の径方向の厚さを、先端縁に向かう程薄くしている（剛性を低くしている）。この為、前記ステアリングシャフトを製造すべく、前記アウタシャフト１２ａと前記インナシャフト１３ａとを互いに近づく方向に軸方向に相対変位させる際に、前記大径部１６ａの先端縁と前記小径部１４の内周面とが強く擦れ合う事を、より効果的に防止できる。即ち、この大径部１６ａの先端縁部分の径方向に関する剛性は、この部分の厚さが薄い分だけ低くなっており、この先端縁部分と前記小径部１４の内周面との当接圧を更に低くできる。この為、前記両シャフト１２ａ、１３ａ同士を相対変位させる際に、前記大径部１６ａの先端縁部分と前記小径部１４の内周面との間に作用する摩擦を更に小さく抑える事ができる。この結果、前記先端縁部分がこの内周面に食い込む事をより効果的に防止でき、この内周面にかじりによる余肉部（むしれ）が発生するのをより確実に防止して、ステアリングシャフトの製造コストの上昇を更に抑える事ができる。尚、前記両シャフト１２ａ、１３ａ同士を径方向内方に押圧する際に、前記面取り部２２の基端部（小径側端部）を、前記両押圧片１８ａ、１８ａの軸方向中間部（これら両押圧片１８ａ、１８ａの厚さ範囲内）のうち、前記両面取り部２１ａ、２１ｂを形成した軸方向両端縁を除いた部分の径方向内方に位置させている。この為、前記大径部１６ａの先端縁で径方向の厚さが薄くなっている部分を径方向内方に押圧する力を適切に制御（中間寄り部分よりも大きくなる事を防止）できる。この結果、前記大径部１６ａと前記小径部１４との係合部の保持力を確保し、しかも、前記大径部１６ａの先端縁と小径部１４の内周面との擦れ合い部でかじりが生じる事を、より安定して防止できる。   Further, in the case of this example, an R-shaped chamfered portion 22 is provided on the inner peripheral edge of the distal end portion of the large-diameter portion 16a of the circular inner shaft 13a, and the radial thickness of the distal end portion of the large-diameter portion 16a is set to The thinner it is, the lower the rigidity. For this reason, when the outer shaft 12a and the inner shaft 13a are relatively displaced in the axial direction so as to approach each other in order to manufacture the steering shaft, the leading edge of the large diameter portion 16a and the inner diameter of the small diameter portion 14 It is possible to more effectively prevent the peripheral surface from rubbing strongly. That is, the rigidity in the radial direction of the tip edge portion of the large diameter portion 16a is reduced by the thickness of this portion, and the contact pressure between the tip edge portion and the inner peripheral surface of the small diameter portion 14 is reduced. Can be further reduced. For this reason, when the shafts 12a and 13a are relatively displaced, the friction acting between the tip edge portion of the large diameter portion 16a and the inner peripheral surface of the small diameter portion 14 can be further reduced. As a result, it is possible to more effectively prevent the leading edge portion from biting into the inner peripheral surface, and it is possible to more reliably prevent a surplus portion due to galling on the inner peripheral surface. An increase in the manufacturing cost of the shaft can be further suppressed. When the shafts 12a and 13a are pressed inward in the radial direction, the base end portion (small-diameter side end portion) of the chamfered portion 22 is connected to the axially intermediate portion of the pressing pieces 18a and 18a (these portions). Among the pressing pieces 18a and 18a), the pressing portions 18a and 18a are positioned inward in the radial direction of the portion excluding both end edges in the axial direction where the double-sided portions 21a and 21b are formed. For this reason, it is possible to appropriately control the force that presses the radially thin portion of the distal end edge of the large diameter portion 16a in the radial direction (prevents becoming larger than the intermediate portion). As a result, the holding force of the engaging portion between the large diameter portion 16a and the small diameter portion 14 is ensured, and the edge of the large diameter portion 16a and the inner peripheral surface of the small diameter portion 14 are galvanized. Can be prevented more stably.

［実施の形態の第２例］
図３も、全ての請求項に対応する、本発明の実施の形態の第２例を示している。本例の場合には、インナシャフト１３ｂの大径部１６ｂの先端部（図３の右端部）に凹孔２３を設け、この凹孔２３の内周面のうち、この大径部１６ｂの先端縁寄り部分に、母線形状が直線状の（部分円すい凹面状の）面取り部２２ａを設けている。この面取り部２２ａの基端部（小径側端部）は、１対の押圧片１８ａ、１８ａによりアウタシャフト１２ａとインナシャフト１３ｂとを押圧する際に、これら両押圧片１８ａ、１８ａの軸方向中間部の径方向内方に位置させる。
その他の部分の構成及び作用は、上述した実施の形態の第１例と同様であるから、同等部分には同一符号を付して、重複する説明は省略する。 [Second Example of Embodiment]
FIG. 3 also shows a second example of an embodiment of the invention corresponding to all claims. In the case of this example, a concave hole 23 is provided at the distal end portion (the right end portion in FIG. 3) of the large diameter portion 16b of the inner shaft 13b, and the distal end of the large diameter portion 16b is formed on the inner peripheral surface of the concave hole 23. A chamfered portion 22a having a straight line shape (partially conical concave shape) is provided near the edge. When the outer shaft 12a and the inner shaft 13b are pressed by the pair of pressing pieces 18a and 18a, the base end portion (small diameter side end portion) of the chamfered portion 22a is an axially intermediate portion between the pressing pieces 18a and 18a. Positioned radially inward of the part.
Since the configuration and operation of the other parts are the same as those of the first example of the embodiment described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

［実施の形態の第３例］
図４も、全ての請求項に対応する、本発明の実施の形態の第３例を示している。本例の場合には、１対の押圧片１８ｂ、１８ｂの押圧面を、面取り部２１ｂを設けた小径部１４の先端側端縁（図４の左側）を除いて、大径部１６の先端縁に向かう程、互いに離れる方向に傾斜させた、傾斜面部２４、２４としている。この構成により、アウタシャフト１２ａの先端部とインナシャフト１３の先端部とを嵌合させた状態でこれら両先端部を塑性変形させた後、これら両シャフト１２ａ、１３同士を近付ける際に、前記大径部１６の先端縁と前記小径部１４の内周面との擦れ合い部にかじりが発生する事を、より効果的に防止できる。
その他の部分の構成及び作用は、前述した実施の形態の第１例と同様であるから、同等部分には同一符号を付して、重複する説明は省略する。 [Third example of embodiment]
FIG. 4 also shows a third example of an embodiment of the invention corresponding to all claims. In the case of this example, the pressing surfaces of the pair of pressing pieces 18b, 18b are arranged at the tip of the large-diameter portion 16 except for the end edge (left side in FIG. 4) of the small-diameter portion 14 provided with the chamfered portion 21b. It is set as the inclined surface parts 24 and 24 inclined to the direction which leaves | separates mutually, so that it goes to an edge. With this configuration, after the tip portions of the outer shaft 12a and the tip portion of the inner shaft 13 are fitted with each other, the tip portions are plastically deformed, and then when the shafts 12a and 13 are brought close to each other, It is possible to more effectively prevent the occurrence of galling in the rubbing portion between the tip edge of the diameter portion 16 and the inner peripheral surface of the small diameter portion 14.
Since the configuration and operation of the other parts are the same as those in the first example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

［実施の形態の第４例］
図５も、全ての請求項に対応する、本発明の実施の形態の第４例を示している。本例の場合には、１対の押圧片１８ｃの押圧面を、小径部１４の先端側（図５の左側）から順に、面取り部２１ｂ、部分円筒面部２５、傾斜面部２４ａとしている。この様な本例によれば、前記両押圧片１８ｃの押圧面に、それぞれ部分円筒面部２５を設けている為、前記小径部１４の内周面の雌セレーション１５と、大径部１６の外周面の雄セレーション１７とが強く摩擦係合している部分の軸方向長さを、或る程度確保できる。この結果、前記大径部１６と前記小径部１４との係合部に於ける保持力を、前述した実施の形態の第３例の場合と比較して、安定させる事ができる。
その他の部分の構成及び作用は、前述した実施の形態の第１例と同様であるから、同等部分には同一符号を付して、重複する説明は省略する。 [Fourth Example of Embodiment]
FIG. 5 also shows a fourth example of an embodiment of the present invention corresponding to all claims. In the case of this example, the pressing surfaces of the pair of pressing pieces 18c are a chamfered portion 21b, a partial cylindrical surface portion 25, and an inclined surface portion 24a in order from the distal end side (left side in FIG. 5) of the small diameter portion 14. According to this example, since the partial cylindrical surface portions 25 are provided on the pressing surfaces of the pressing pieces 18c, the female serration 15 on the inner peripheral surface of the small diameter portion 14 and the outer periphery of the large diameter portion 16 are provided. It is possible to secure a certain length in the axial direction of the portion in which the male serration 17 of the surface is in strong frictional engagement. As a result, the holding force at the engaging portion between the large diameter portion 16 and the small diameter portion 14 can be stabilized as compared with the third example of the embodiment described above.
Since the configuration and operation of the other parts are the same as those in the first example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

１ 車体
２ ステアリングコラム
３、３ａ ステアリングシャフト
４ ステアリングホイール
５ａ、５ｂ 自在継手
６ 中間シャフト
７ ステアリングギヤユニット
８ 入力軸
９ タイロッド
１０ 電動モータ
１１ アウタコラム
１２、１２ａ アウタシャフト
１３、１３ａ〜１３ｂ インナシャフト
１４ 小径部
１５ 雌セレーション
１６、１６ａ〜１６ｂ 大径部
１７ 雄セレーション
１８、１８ａ〜１８ｃ 押圧片
１９ 凹部
２０ 隙間
２１ａ、２１ｂ 面取り部
２２、２２ａ 面取り部
２３ 凹孔
２４、２４ａ 傾斜面部
２５ 部分円筒面部 DESCRIPTION OF SYMBOLS 1 Car body 2 Steering column 3, 3a Steering shaft 4 Steering wheel 5a, 5b Universal joint 6 Intermediate shaft 7 Steering gear unit 8 Input shaft 9 Tie rod 10 Electric motor 11 Outer column 12, 12a Outer shaft 13, 13a-13b Inner shaft 14 Small diameter Part 15 Female serration 16, 16a to 16b Large diameter part 17 Male serration 18, 18a to 18c Pressing piece 19 Recess 20 Crevice 21a, 21b Chamfered part 22, 22a Chamfered part 23 Recessed hole 24, 24a Inclined surface part 25 Partial cylindrical surface part

Claims (3)

少なくとも先端縁から中間部に掛けての部分の内周面に雌セレーションを形成した管状のアウタシャフトと、少なくとも先端縁から中間部に掛けての部分の外周面にこの雌セレーションと係合する雄セレーションを形成したインナシャフトとを、前記アウタシャフトの先端部とこのインナシャフトの先端部とを係合させた状態で、このアウタシャフトの外周面を径方向内方に押圧する事により、このアウタシャフトの先端部及び前記インナシャフトの先端部を径方向に塑性変形させた後、このアウタシャフトとこのインナシャフトとを互いに近づく方向に軸方向に相対変位させて、このアウタシャフトの先端部をこのインナシャフトの中間部に圧入嵌合すると共に、このインナシャフトの先端部を前記アウタシャフトの中間部に圧入嵌合させ、このアウタシャフトの先端部と中間部との間部分と、前記インナシャフトの先端部と中間部との間部分とを互いに緩く係合させる衝撃吸収式ステアリングシャフトの製造方法に於いて、前記アウタシャフトの先端部の外周面を径方向内方に押圧する量を、前記インナシャフトの先端部の先端縁寄り部分で、同じく中間部寄り部分よりも少なくする事を特徴とする衝撃吸収式ステアリングシャフトの製造方法。   A tubular outer shaft in which female serrations are formed on the inner peripheral surface of at least a portion extending from the leading edge to the intermediate portion, and a male that engages with the female serrations on the outer peripheral surface of at least the portion extending from the leading edge to the intermediate portion. By pressing the outer peripheral surface of the outer shaft radially inward in a state where the tip of the outer shaft and the tip of the inner shaft are engaged with the inner shaft on which the serration is formed, After plastically deforming the distal end of the shaft and the distal end of the inner shaft in the radial direction, the outer shaft and the inner shaft are relatively displaced in the axial direction so as to approach each other, and the distal end of the outer shaft is The inner shaft is press-fitted to the middle part, and the inner shaft tip is press-fitted to the outer shaft middle part. In the method of manufacturing an impact-absorbing steering shaft in which the portion between the front end portion and the intermediate portion of the outer shaft and the portion between the front end portion and the intermediate portion of the inner shaft are loosely engaged with each other, The shock absorbing steering shaft is characterized in that the amount of pressing the outer peripheral surface of the tip portion radially inward is less at the portion near the tip edge of the tip portion of the inner shaft than at the portion near the middle portion. Production method. 前記アウタシャフトは、一端部に少なくとも内径を小さくした小径部を設け、この小径部の内周面に雌セレーションを形成しているものであり、前記インナシャフトは、一端部に少なくとも外径を大きくした大径部を設け、この大径部の外周面に前記雌セレーションと係合する雄セレーションを形成しているものであり、前記小径部の先端部と前記大径部の先端部とを係合させた状態で、この小径部の外周面を径方向内方に押圧する事により、この小径部の先端部及び前記大径部の先端部を径方向に塑性変形させる際に、この小径部の先端部の外周面を径方向内方に押圧する量を、前記大径部の先端部の先端縁寄り部分で、同じく中間部寄り部分よりも少なくし、その後、前記アウタシャフトと前記インナシャフトとを互いに近づく方向に軸方向に相対変位させて、前記小径部の先端部を前記大径部の基端部に圧入嵌合すると共に、この大径部の先端部をこの小径部の基端部に圧入嵌合させ、これら小径部の中間部と大径部の中間部とを互いに緩く係合させる、請求項１に記載の衝撃吸収式ステアリングシャフトの製造方法。   The outer shaft is provided with a small-diameter portion having at least a small inner diameter at one end portion, and a female serration is formed on the inner peripheral surface of the small-diameter portion. The inner shaft has at least a large outer diameter at one end portion. And a male serration that engages with the female serration is formed on the outer peripheral surface of the large diameter portion, and the distal end portion of the small diameter portion and the distal end portion of the large diameter portion are engaged with each other. When the outer peripheral surface of the small-diameter portion is pressed radially inward in the combined state, the small-diameter portion is deformed when the tip of the small-diameter portion and the tip of the large-diameter portion are plastically deformed in the radial direction. The amount of pressing the outer peripheral surface of the tip portion inward in the radial direction is made smaller at the portion near the tip edge of the tip portion of the large diameter portion than at the portion near the middle portion, and then the outer shaft and the inner shaft Axis in the direction of approaching each other Relative displacement in the direction, and press-fitting the distal end portion of the small diameter portion to the proximal end portion of the large diameter portion, and press-fitting the distal end portion of the large diameter portion to the proximal end portion of the small diameter portion, The method of manufacturing an impact-absorbing steering shaft according to claim 1, wherein the intermediate portion of the small diameter portion and the intermediate portion of the large diameter portion are loosely engaged with each other. 前記アウタシャフトの先端部の外周面を径方向内方に押圧する量を、前記インナシャフトの先端縁に向かう程少なくする、請求項１〜２のうちの何れか１項に記載の衝撃吸収式ステアリングシャフトの製造方法。   The shock absorption type according to any one of claims 1 to 2, wherein an amount of pressing an outer peripheral surface of a front end portion of the outer shaft radially inward is decreased toward a front end edge of the inner shaft. A method for manufacturing a steering shaft.
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RU2553068C2 (en) * 2013-06-19 2015-06-10 Федеральное государственное казенное военное образовательное учреждение высшего профессионального образования "Военно-космическая академия имени А.Ф. Можайского" Министерства обороны Российской Федерации Method of transmitting information using noiseless coding

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001030920A (en) * 1999-03-04 2001-02-06 Nsk Ltd Shock absorbing steering shaft and manufacture thereof
JP3168841B2 (en) * 1994-09-22 2001-05-21 日本精工株式会社 Manufacturing method of shock absorbing steering shaft
JP2003205844A (en) * 2002-01-11 2003-07-22 Nsk Ltd Shock absorbing type steering shaft

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3168841B2 (en) * 1994-09-22 2001-05-21 日本精工株式会社 Manufacturing method of shock absorbing steering shaft
JP2001030920A (en) * 1999-03-04 2001-02-06 Nsk Ltd Shock absorbing steering shaft and manufacture thereof
JP2003205844A (en) * 2002-01-11 2003-07-22 Nsk Ltd Shock absorbing type steering shaft

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3219430A1 (en) 2016-03-15 2017-09-20 Omron Corporation Laser machining system and machining control method

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