JPH07268481A - High-frequency hardening method of rack shaft - Google Patents
High-frequency hardening method of rack shaftInfo
- Publication number
- JPH07268481A JPH07268481A JP6059433A JP5943394A JPH07268481A JP H07268481 A JPH07268481 A JP H07268481A JP 6059433 A JP6059433 A JP 6059433A JP 5943394 A JP5943394 A JP 5943394A JP H07268481 A JPH07268481 A JP H07268481A
- Authority
- JP
- Japan
- Prior art keywords
- tooth
- rack shaft
- shaft
- hardening
- quenching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- Heat Treatment Of Articles (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は自動車等車両のステアリ
ング装置の部品として用いられるラックシャフトの高周
波焼入法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction hardening method for a rack shaft used as a part of a steering device of a vehicle such as an automobile.
【０００２】[0002]
【従来の技術】ラックシャフトは軸部の一端に、ステア
リングシャフトの先端に取り付けた斜め方向に歯すじを
持つピニオンと、歯合する平面歯切りしたラック部（歯
部）を有するシャフトである。2. Description of the Related Art A rack shaft is a shaft having, at one end of a shaft portion, a pinion having a toothed line which is attached to the tip of a steering shaft in an oblique direction, and a rack portion (tooth portion) which is meshed with a plane.
【０００３】例えば、特開昭５９−９１２４号公報には
ラックシャフトの歯面およびその背面に高周波電流を通
電すると共に、歯面およびその背面に冷却水を噴射可能
な近接導体を配置し高周波電流を通電し、ラックシャフ
トの歯面およびその背面を同時に焼入焼もどしすること
により、ラックシャフトの曲げ強度を向上させるステア
リング用ラックバーの焼入装置が開示されている。ま
た、軸部に強度を持たせるために、歯部に熱処理を施し
た後、改めて軸部に焼入れをすることがある。For example, in JP-A-59-9124, a high frequency current is applied to the tooth surface and the back surface of the rack shaft, and a proximity conductor capable of injecting cooling water is arranged on the tooth surface and the back surface of the rack shaft. There is disclosed a quenching device for a steering rack bar that improves the bending strength of the rack shaft by simultaneously quenching and tempering the tooth surface and the back surface of the rack shaft by energizing. Further, in order to give strength to the shaft, the teeth may be heat treated and then the shaft may be hardened again.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、ラック
シャフトの歯面とその背面を同時に高周波焼入焼もどし
する前記提案においては、歯面側とその背面側で焼入れ
の体積が異なるため、ラックシャフトが軸方向に対して
反ってしまうという問題点がある。また、軸部に強度を
持たせるため、別途焼入焼もどし処理を行った場合、工
程が増えるため、さらには歯部と軸部の境界部に未硬化
部分が出来る可能性がある。However, in the above-mentioned proposal in which the tooth surface and the back surface of the rack shaft are simultaneously induction hardened and tempered, since the tooth surface side and the back surface side have different quenching volumes, the rack shaft is There is a problem that it warps in the axial direction. In addition, when the quenching and tempering treatment is separately performed to give strength to the shaft portion, the number of steps is increased, and further, an uncured portion may be formed at the boundary portion between the tooth portion and the shaft portion.
【０００５】本発明はラックシャフトの焼入焼もどしに
おける前記のごとき問題点を解決すべくなされたもので
あって、焼入歪が少なく、歯曲げ疲労強度に優れ、熱処
理時間を短縮できるラックシャフトの高周波焼入法を提
供することを目的とする。The present invention has been made to solve the above problems in the quenching and tempering of a rack shaft. The rack shaft has little quenching strain, is excellent in tooth bending fatigue strength, and can shorten the heat treatment time. The purpose of the present invention is to provide an induction hardening method.
【０００６】[0006]
【課題を解決するための手段】発明者等はラックシャフ
トに焼入歪の生ずる原因が、歯部の歯面側とその背面と
でその焼入体積のバランスを欠くことにあることに鑑
み、被処理物であるラックシャフトと高周波コイルとの
クリアランスを調整して、歯部の歯面側の焼入体積とそ
の背面側の焼入体積をほぼ同一にして見たところ、焼入
歪が著しく減少することを新たに知見して本発明を完成
した。また、ラックシャフトの歯面側の歯部から軸部に
到るまでの範囲と、背面側の歯部背面から軸部に到るま
での範囲を、同時に高周波焼入れすることにより、焼入
歪が減少すると共に熱処理時間を短縮することに成功し
て本発明を完成した。SUMMARY OF THE INVENTION The inventors of the present invention have considered that the cause of quenching distortion in a rack shaft is that the quenching volume is unbalanced between the tooth flank and the back of the tooth portion. When the clearance between the rack shaft, which is the object to be processed, and the high frequency coil was adjusted, and the quenching volume on the tooth flank side of the tooth and the quenching volume on the back side were almost the same, the quenching strain was remarkable. The present invention has been completed by newly finding that it decreases. Also, by quenching the range from the tooth surface side of the rack shaft to the shaft portion to the shaft portion and the back surface tooth portion from the back surface to the shaft portion at the same time, quenching distortion The present invention was completed by succeeding in reducing the heat treatment time as well as the heat treatment time.
【０００７】本発明の請求項１のラックシャフトの高周
波焼入法は、高周波焼入によりラックシャフトの歯部の
歯面と背面に同時に焼入層を形成し、歯面側の焼入体積
と歯面に対する背面側の焼入体積をほぼ等しくすること
を要旨とする。In the induction hardening method for a rack shaft according to claim 1 of the present invention, a hardening layer is simultaneously formed on the tooth surface and the back surface of the tooth portion of the rack shaft by induction hardening to obtain a hardening volume on the tooth surface side. The gist is to make the quenching volume on the back surface side approximately equal to the tooth surface.
【０００８】また、本発明の請求項２のラックシャフト
の高周波焼入法は、請求項１のラックシャフト焼入法に
おいて、ラックシャフトの歯面側の歯部から軸部に到る
までの範囲と、背面側の歯部背面から軸部に到るまでの
範囲を、同時に高周波焼入れすることを要旨とする。Further, the induction hardening method for the rack shaft according to claim 2 of the present invention is the range from the tooth portion on the tooth flank side of the rack shaft to the shaft portion in the rack shaft quenching method according to claim 1. And the range from the back side of the tooth portion to the shaft portion is induction hardened at the same time.
【０００９】[0009]
【作用】請求項１の発明では、ラックシャフトの歯部の
歯面と背面に同時に、かつ等しい体積の焼入層が形成さ
れるため、精度が良く焼入歪の少ないラックシャフトが
得られる。また、請求項２の発明では、従来歯部と軸部
の焼入れを別工程で行っていたため、軸部と歯部の間に
未硬化部があったが、一体に焼入れすることにより、未
硬化部分がなくなるため精度が向上し、また一回の工程
で歯面には強度を、軸部には耐摩耗性が付与できるた
め、生産性が向上する。According to the first aspect of the present invention, since the hardened layer having the same volume is formed on the tooth surface and the back surface of the tooth portion of the rack shaft at the same time, a rack shaft having high accuracy and less quenching distortion can be obtained. Further, in the invention of claim 2, since the tooth portion and the shaft portion are conventionally hardened in separate steps, there is an uncured portion between the shaft portion and the tooth portion. The precision is improved because the parts are eliminated, and the productivity is improved because strength can be imparted to the tooth surface and wear resistance can be imparted to the shaft portion in one step.
【００１０】[0010]
【実施例】本発明の実施例を従来例と対比して説明し、
本発明の効果を明らかにする。図４〜図６に示す高周波
焼入装置を用い、上高周波コイル３と下高周波コイル４
との間に、材質Ｓ４５Ｃで作成したラックシャフト１を
配置した。その際、図４〜図６に示すように、歯部１ａ
における歯面と上高周波コイル３の凸部３ｂとの間イお
よび背面と下高周波コイル４の凸部４ｂとの間隙ロは、
軸部１ｂと上下の高周波コイル３および４との間隙ハお
よびニより狭くなり、かつ歯部１ａにおける歯面側と背
面側の焼入体積を等しくするため、歯面側の間隙イより
も背面側の間隙ロの方を狭くした。EXAMPLES Examples of the present invention will be described in comparison with conventional examples,
The effect of the present invention will be clarified. Using the induction hardening apparatus shown in FIGS. 4 to 6, an upper high frequency coil 3 and a lower high frequency coil 4 are used.
The rack shaft 1 made of the material S45C was arranged between the two. At that time, as shown in FIG. 4 to FIG.
The gap between the tooth surface and the convex portion 3b of the upper high-frequency coil 3 and the gap between the rear surface and the convex portion 4b of the lower high-frequency coil 4 are:
The gap between the shaft portion 1b and the upper and lower high-frequency coils 3 and 4 is narrower than the gaps c and d, and the hardened volume on the tooth surface side and the back surface side of the tooth portion 1a are equalized. The gap B on the side was narrowed.
【００１１】次いで、高周波コイルに通電し、周波数４
０ｋＨｚで電力２５０ｋｗで加熱時間５秒加熱し、所要
の温度（９５０℃）に到達後直ちに焼入液を上下の高周
波コイル３および４の冷却水噴射孔２から噴射し、冷却
し焼入層２を形成した。次いで、同じ設備の電力を２５
ｋｗで加熱時間１０秒間加熱し、焼入層２の焼戻しを行
いラックシャフトの熱処理を完了した。Next, the high-frequency coil is energized and the frequency 4
After heating at 0 kHz and 250 kw for 5 seconds, the quenching liquid is injected from the cooling water injection holes 2 of the upper and lower high frequency coils 3 and 4 immediately after reaching the required temperature (950 ° C.), and the quenching layer 2 is cooled. Was formed. Then, power of the same equipment is 25
The quenching layer 2 was tempered by heating at kW for a heating time of 10 seconds to complete the heat treatment of the rack shaft.
【００１２】続いて、本実施例で高周波焼入焼戻しした
ラックシャフトと、従来のラックシャフトと高周波コイ
ルの間隙を上下とも等しくして熱処理したラックシャフ
トについて、焼入歪、歯曲げ疲労強度および全熱処理加
工時間について比較した。なお、焼入歪については、ラ
ックシャフトの両端をＶブロックで受けて、中央部の焼
入歪をダイヤルゲージで測定した。また、歯曲げ疲労強
度については、刻設された複数枚のラック歯のうち４枚
の歯を残してラックシャフトの両方から挟むようにセッ
トして、任意の荷重を繰り返し負荷し破壊するまでの回
数で評価した。Then, the induction hardening and tempering rack shaft in this example and the conventional rack shaft heat-treated with the gap between the rack shaft and the induction coil being equal to each other at the upper and lower sides, the hardening strain, the tooth bending fatigue strength and the total strength. The heat treatment time was compared. Regarding the quenching strain, both ends of the rack shaft were received by V blocks, and the quenching strain at the center was measured with a dial gauge. Regarding the tooth bending fatigue strength, it was set so that it was sandwiched from both rack shafts, leaving four teeth out of a plurality of engraved rack teeth, until it was repeatedly loaded with an arbitrary load and destroyed. It was evaluated by the number of times.
【００１３】焼入歪については、図１に示したように、
従来品が１．０〜３．０ｍｍであったのに対して、本実
施例は０．３〜０．７ｍｍであって、本発明法によれば
焼入歪が著しく減少することが判明した。また、歯曲げ
疲労強度については、図２に示したように、従来品は
０．９×１０7 回でラックシャフトが破壊したのに対し
て、本発明の実施例では１．６×１０7 回と著しく向上
した。軸部までの熱処理時間を含めた全熱処理加工時間
については、図３に示したように、従来品の時間を１．
０とした場合、本発明の実施例の時間は０．５と処理時
間が半減しており、著しく生産性が向上することが確認
された。Regarding quenching strain, as shown in FIG.
In contrast to the conventional product having a thickness of 1.0 to 3.0 mm, this embodiment has a thickness of 0.3 to 0.7 mm, and it has been found that the quenching strain is significantly reduced according to the method of the present invention. . Regarding the tooth bending fatigue strength, as shown in FIG. 2, the rack shaft broke at 0.9 × 10 7 times in the conventional product, whereas it was 1.6 × 10 7 in the example of the present invention. The number has improved significantly. As for the total heat treatment processing time including the heat treatment time up to the shaft portion, as shown in FIG.
When it was set to 0, the processing time of the example of the present invention was 0.5, which was half the processing time, and it was confirmed that the productivity was remarkably improved.
【００１４】なお、本実施例で用いた高周波コイルを用
いて、ラックシャフトを前述の加熱条件で加熱後、別の
ステーションに移動させて、ラックシャフトを回転させ
ずに拘束させながら冷却し、焼入を行うことにより、ラ
ックシャフトの焼入歪がより小さくなり、高精度のラッ
クシャフトが得られる。The high frequency coil used in this embodiment was used to heat the rack shaft under the above-mentioned heating conditions, move it to another station, cool it while restraining it without rotating it, and burn it. By performing the quenching, the quenching distortion of the rack shaft becomes smaller, and a highly accurate rack shaft can be obtained.
【００１５】[0015]
【発明の効果】本発明のラックシャフトの高周波焼入法
は以上詳述したように、高周波焼入によりラックシャフ
トの歯部の歯面と背面に同時に焼入層を形成し、歯面側
の焼入体積と歯面に対する背面側の焼入体積をほぼ等し
くすると共に、ラックシャフトの歯面側の歯部から軸部
に到るまでの範囲と、背面側の歯部背面から軸部に到る
までの範囲を、同時に高周波焼入れするものであって、
ラックシャフトの歯部の歯面と背面に同時に、かつ等し
い体積の焼入層が形成されるため、精度が良く焼入歪の
少なく、歯元まで焼入れが可能なので耐久性にすぐれた
ラックシャフトが得られる。また、一体に焼入れするこ
とにより、歯部と軸部の境界の未硬化部分がなくなるた
め精度が向上し、また一回の工程で歯面には強度を、軸
部には耐摩耗性が付与できるため、生産性が向上する。As described above in detail, the induction hardening method for the rack shaft of the present invention forms a hardening layer on the tooth surface and the back surface of the tooth portion of the rack shaft by induction hardening at the same time. The volume of quenching and the volume of quenching on the back side relative to the tooth surface are made approximately equal, and the range from the tooth portion on the tooth surface side of the rack shaft to the shaft portion and from the tooth surface on the rear surface side to the shaft portion are reached. Induction hardening at the same time,
Since a hardened layer of the same volume is formed on the tooth surface and back surface of the rack shaft teeth at the same time, the rack shaft is highly accurate and has less quenching distortion and can be hardened to the root of the rack shaft. can get. In addition, by integrally quenching, the uncured portion at the boundary between the tooth part and the shaft part is eliminated, so accuracy is improved, and in one process, the tooth surface is given strength and the shaft part is given wear resistance. Therefore, productivity is improved.
【図１】本発明の実施例と従来例の焼入歪を示す図であ
る。FIG. 1 is a diagram showing quenching strains of an example of the present invention and a conventional example.
【図２】本発明の実施例と従来例の歯曲げ疲労強度を示
す図である。FIG. 2 is a diagram showing tooth bending fatigue strength of an example of the present invention and a conventional example.
【図３】本発明の実施例と従来例の全熱処理加工時間を
示す図である。FIG. 3 is a diagram showing a total heat treatment processing time of an example of the present invention and a conventional example.
【図４】本発明の実施に用いられた高周波焼入装置の側
断面図である。FIG. 4 is a side sectional view of an induction hardening apparatus used for carrying out the present invention.
【図５】図４にＡ−Ａ線における断面図である。5 is a cross-sectional view taken along the line AA in FIG.
【図６】図４にＢ−Ｂ線における断面図である。6 is a cross-sectional view taken along the line BB in FIG.
１ ラックシャフト １ａ ラックシャフトの歯部 １ｂ ラックシャフトの軸部 ２ 焼入層 ３ 上高周波コイル ３ａ 上高周波コイルのスプリンクラ ３ｂ 上高周波コイルの凸部 ４ 下高周波コイル ４ａ 下高周波コイルスプリンクラ ４ｂ 下高周波コイルの凸部 1 Rack Shaft 1a Rack Shaft Teeth 1b Rack Shaft Shaft 2 Hardened Layer 3 Upper High Frequency Coil 3a Upper High Frequency Coil Sprinkler 3b Upper High Frequency Coil Convex 4 Lower High Frequency Coil 4a Lower High Frequency Coil Sprinkler 4b Lower High Frequency Coil Convex
Claims (2)
の歯面と背面に同時に焼入層を形成し、歯面側の焼入体
積と歯面に対する背面側の焼入体積をほぼ等しくするこ
とを特徴とするラックシャフトの高周波焼入法。1. A quenching layer is simultaneously formed on a tooth surface and a back surface of a tooth portion of a rack shaft by induction hardening, so that a quenching volume on the tooth surface side and a quenching volume on the back surface side with respect to the tooth surface are substantially equalized. Induction hardening method for rack shafts.
に到るまでの範囲と、背面側の歯部背面から軸部に到る
までの範囲を、同時に高周波焼入れすることを特徴とす
る請求項１に記載のラックシャフトの高周波焼入法。2. The induction hardening is performed simultaneously on a range from a tooth portion on a tooth surface side of a rack shaft to a shaft portion and a range from a back surface of a tooth portion on a back surface side to a shaft portion. The induction hardening method for a rack shaft according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6059433A JPH07268481A (en) | 1994-03-29 | 1994-03-29 | High-frequency hardening method of rack shaft |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6059433A JPH07268481A (en) | 1994-03-29 | 1994-03-29 | High-frequency hardening method of rack shaft |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07268481A true JPH07268481A (en) | 1995-10-17 |
Family
ID=13113142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6059433A Pending JPH07268481A (en) | 1994-03-29 | 1994-03-29 | High-frequency hardening method of rack shaft |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07268481A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6502473B1 (en) * | 1999-10-01 | 2003-01-07 | Toyota Jidosha Kabushiki Kaisha | Rack bar and manufacturing method thereof |
| JP2010522276A (en) * | 2007-03-28 | 2010-07-01 | イーエフディー・インダクション・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング | Inductor for induction hardening of rod-shaped metal rack |
| JP2014133929A (en) * | 2013-01-11 | 2014-07-24 | Miyaden Co Ltd | High-frequency induction hardening apparatus for rack bar |
-
1994
- 1994-03-29 JP JP6059433A patent/JPH07268481A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6502473B1 (en) * | 1999-10-01 | 2003-01-07 | Toyota Jidosha Kabushiki Kaisha | Rack bar and manufacturing method thereof |
| JP2010522276A (en) * | 2007-03-28 | 2010-07-01 | イーエフディー・インダクション・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング | Inductor for induction hardening of rod-shaped metal rack |
| JP2014133929A (en) * | 2013-01-11 | 2014-07-24 | Miyaden Co Ltd | High-frequency induction hardening apparatus for rack bar |
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