JPH06122925A - Quenching method of gear - Google Patents

Quenching method of gear

Info

Publication number
JPH06122925A
JPH06122925A JP3119234A JP11923491A JPH06122925A JP H06122925 A JPH06122925 A JP H06122925A JP 3119234 A JP3119234 A JP 3119234A JP 11923491 A JP11923491 A JP 11923491A JP H06122925 A JPH06122925 A JP H06122925A
Authority
JP
Japan
Prior art keywords
cooling
gear
quenching
tooth
liquid
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.)
Granted
Application number
JP3119234A
Other languages
Japanese (ja)
Other versions
JP3230822B2 (en
Inventor
Isao Matsumoto
勲 松本
Yoshiaki Wada
義彰 和田
Shingo Ishii
薪悟 石井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DKK Co Ltd
Original Assignee
Denki Kogyo Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Denki Kogyo Co Ltd filed Critical Denki Kogyo Co Ltd
Priority to JP11923491A priority Critical patent/JP3230822B2/en
Publication of JPH06122925A publication Critical patent/JPH06122925A/en
Application granted granted Critical
Publication of JP3230822B2 publication Critical patent/JP3230822B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

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  • Heat Treatment Of Articles (AREA)

Abstract

PURPOSE:To prevent the generation of complicated internal stress at the time of quench cooling and to prevent the generation of quenching cracks and quenching strains (deformation). CONSTITUTION:In a state in which a gear 14 to be quenched is rotated round its axial center, the tooth surface 13a is uniformly heated to a required temp. After that, the rotation of this gear 13 is stopped, a coolant is sprayed on the bottom 13c of the gear 13, the coolant is flowed along the addendum 13b from the bottom 13c and quench cooling is executed.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、歯車の焼入方法に関
し、更に詳しくは、所要の焼入温度に加熱した歯車に冷
却液を噴射して歯面を焼入冷却する方法の改良に関する
ものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quenching a gear, and more particularly to an improvement in a method for quenching and cooling a tooth surface by injecting a cooling liquid into a gear heated to a required quenching temperature. Is.

【0002】[0002]

【従来の技術】歯車の焼入方法としては、通常、回転一
発(定置)焼入方法が用いられている。図8〜図10
は、この種の焼入方法を実施するために従来より用いら
れている高周波焼入装置1を示すものであって、この装
置1は、内部に冷却液通路2を有しかつ内周面に多数の
冷却液噴射孔3を有する円環状の高周波誘導加熱コイル
4と、歯車5を保持する治具6とから構成されている。
そして、高周波誘導加熱コイル4にはリード部7a,7
bを介して高周波電源8から高周波電流が供給されると
共に、高周波誘導加熱コイル4の冷却液通路2には複数
の冷却液供給パイプ9を通して冷却液が供給されるよう
になっている。
2. Description of the Related Art As a hardening method for gears, a rotating one shot (stationary) hardening method is usually used. 8 to 10
Shows an induction hardening apparatus 1 that has been conventionally used to carry out this type of hardening method. The apparatus 1 has a cooling liquid passage 2 inside and an inner peripheral surface. It is composed of an annular high-frequency induction heating coil 4 having a large number of coolant injection holes 3 and a jig 6 for holding a gear 5.
The high frequency induction heating coil 4 has lead portions 7a, 7
A high frequency current is supplied from a high frequency power source 8 via b, and a cooling liquid is supplied to the cooling liquid passage 2 of the high frequency induction heating coil 4 through a plurality of cooling liquid supply pipes 9.

【0003】なお、上述の冷却液噴射孔3は、図10に
示すように、いわゆる千鳥状に配列されている。また、
噴射孔3の直径D、噴射孔3の水平方向及び幅方向の配
列間隔L及びW、並びに噴射孔3の軸線方向と歯面5a
とのなす角度が焼入れ結果に大きな影響を及ぼすので、
これらの諸条件は、歯車5の形状、寸法及びモジュール
等に応じて決定される。
The cooling liquid injection holes 3 are arranged in a so-called zigzag pattern as shown in FIG. Also,
The diameter D of the injection hole 3, the arrangement intervals L and W of the injection hole 3 in the horizontal direction and the width direction, and the axial direction of the injection hole 3 and the tooth surface 5a.
Since the angle formed by and has a great influence on the quenching result,
These various conditions are determined according to the shape, size, module, etc. of the gear 5.

【0004】歯車5の歯面5aに焼入れを施すに際して
は、図8及び図9に示すように、歯車5を治具6上に載
置して円環状の高周波誘導加熱コイル4の中央孔4a内
に配置し、治具6と共に歯車5をその軸心を中心に回転
させる。これと同時に、電源8から高周波加波コイル4
に高周波電流を供給することにより、歯車5の歯面5a
を高周波誘導加熱する。そして、歯車5の歯面5aが所
要の焼入温度になった時点で高周波電流の供給を停止す
ると共に、冷却水通路2に冷却液を供給して噴射孔3か
ら回転状態にある前記歯面5aに向けて(歯車5の直径
方向)冷却液を噴射する。これにより、前記歯面5aの
急冷を行ない、歯面5aに焼入硬化層を形成するように
していた。
When quenching the tooth surface 5a of the gear 5, as shown in FIGS. 8 and 9, the gear 5 is placed on the jig 6 and the central hole 4a of the annular high-frequency induction heating coil 4 is placed. It is arranged inside and the gear 5 is rotated around its axis together with the jig 6. At the same time, from the power source 8 to the high frequency exciting coil 4
To the tooth surface 5a of the gear 5 by supplying a high-frequency current to
High frequency induction heating. Then, when the tooth surface 5a of the gear 5 reaches the required quenching temperature, the supply of the high frequency current is stopped and the cooling liquid is supplied to the cooling water passage 2 to rotate the tooth surface from the injection hole 3. The cooling liquid is injected toward 5a (diameter direction of gear 5). Thereby, the tooth surface 5a is rapidly cooled to form a quench-hardened layer on the tooth surface 5a.

【0005】ところで、歯車5等の如き複雑形状を有す
る機械構造用の鋼部品に高周波焼入れを施す場合には、
焼入冷却の方法として既述のような噴射冷却方法を採用
するのが一般的である。噴射冷却のメカニズムはズブ冷
却(被焼入体を冷却液中に浸漬して行なう冷却)のメカ
ニズムと同じであって、蒸気膜段階、沸騰段階及び対流
段階を経て冷却されるが、ズブ冷却に対する噴射冷却の
特徴は、蒸気膜段階が著しく短く、かつ、蒸気膜が破れ
る温度(急冷の始まる温度)が高いことである。これ
は、高速の流体(冷却液)によって固体表面(被焼入体
の表面)に生じた気泡の膜が破られやすいため、沸騰に
よる冷却がズブ冷却の場合に比べて多くなるからであ
る。これが、噴射冷却を従来より採用している主な理由
である。
By the way, when induction hardening is applied to steel parts for machine structures having complicated shapes such as the gear 5,
As a quenching cooling method, it is general to adopt the jet cooling method as described above. The mechanism of jet cooling is the same as that of zub cooling (cooling performed by immersing a material to be quenched in a cooling liquid), and cooling is performed through a vapor film stage, a boiling stage and a convection stage. The features of injection cooling are that the vapor film stage is extremely short and the temperature at which the vapor film breaks (the temperature at which quenching begins) is high. This is because the film of bubbles generated on the solid surface (the surface of the material to be hardened) is easily broken by the high-speed fluid (cooling liquid), so that the cooling by boiling increases as compared with the case of the subcooling. This is the main reason why injection cooling has been adopted conventionally.

【0006】なお、噴射冷却を行なうに当っては、冷却
液の種類、液温、流速、流量、濃度等の諸条件に応じて
焼入後の硬さ、焼割れ、変形、歪み等に重大な影響を及
ぼすことが知られている。一般に、鋼部品の焼入冷却に
用いる冷却液としては、S曲線のノーズに相当する50
0〜600℃付近における冷却速度が大きくて鋼のマル
テンサイト変態点(MS 点)付近以下における冷却速度
が小さくなるようなものが望ましい。ところが、約30
0℃付近における冷却速度を比較すると、図11に示さ
れるように噴射冷却の方がズブ冷却の場合よりも約7倍
も大きいので、噴射冷却を行なうと焼割れや焼歪(変
形)を生じる危険性が大きくなるという問題点がある。
When performing injection cooling, the hardness after quenching, quench cracking, deformation, distortion, etc. are important depending on various conditions such as the type of cooling liquid, liquid temperature, flow velocity, flow rate, and concentration. Is known to have a significant impact. In general, the cooling liquid used for quenching and cooling steel parts is 50 which corresponds to the nose of the S curve.
0 to 600 ° C. and greater cooling rate in the vicinity of the martensite transformation point of the steel (M S point) as near as the cooling rate becomes small at less. However, about 30
Comparing the cooling rates in the vicinity of 0 ° C., as shown in FIG. 11, the injection cooling is about 7 times larger than the case of the zub cooling, so that the injection cooling causes quench cracks and strain (deformation). There is a problem that the risk becomes large.

【0007】また、噴射冷却の場合、最も重要なのは冷
却液の流量或いは圧力の調節と冷却液の種類の選定であ
る。噴射冷却水の流量が冷却曲線(冷却特性)に及ぼす
影響は、図12に示す通りである。この場合、一定配列
の噴射孔を有する同一の冷却環を使用しているので、流
量を大きくしたときは、噴射圧力も大きくなっている。
図12から明らかなように、流量調節によって冷却能を
かなり調節することができる。なお、一般に、噴射流量
ないし噴射圧力が大きくなるほど蒸気膜崩壊温度は上昇
することが知られている。
Further, in the case of injection cooling, the most important factors are adjustment of the flow rate or pressure of the cooling liquid and selection of the type of cooling liquid. The effect of the flow rate of the jet cooling water on the cooling curve (cooling characteristics) is as shown in FIG. In this case, since the same cooling ring having the fixed array of injection holes is used, when the flow rate is increased, the injection pressure is also increased.
As is apparent from FIG. 12, the cooling capacity can be considerably adjusted by adjusting the flow rate. It is generally known that the vapor film collapse temperature increases as the injection flow rate or injection pressure increases.

【0008】[0008]

【発明が解決しようとする課題】上述のように噴射冷却
はズブ冷却に比べて約300℃付近の冷却速度が約7倍
も大きいので焼割れ、焼歪の発生の危険性が大きいとい
う特質を有するのに加えて、歯車5を回転させつつ噴射
冷却することにより歯先5bと歯底5cの冷却速度が異
なってしまうという現象を生じるため(図13参照)、
単純形状部品の場合に比べて、焼割れ等の発生の危険性
がより一層増大する。
As described above, the injection cooling has a characteristic that the cooling rate at about 300 ° C. is about 7 times higher than that of the sub-cooling, so that the risk of occurrence of quench cracks and strains is high. In addition to the above, a phenomenon in which the cooling speed of the tooth tip 5b and the tooth bottom 5c is different due to the jet cooling while rotating the gear 5 occurs (see FIG. 13).
As compared with the case of a simple shaped part, the risk of occurrence of quench cracking is further increased.

【0009】すなわち、従来では、冷却液噴射時に被焼
入体である歯車5は所要の回転速度をもって回転させる
ようにしているため、歯車5の直径方向に向って噴射さ
れる冷却器は、歯車5の歯先5bには良く当るものの、
歯底5cにはあまり良く当たらないのが実状である。そ
のため、歯先5b部分、歯底5c部分及びその中間の歯
側面5d部分では、加熱面の冷却速度がそれぞれ異なる
事態を生じる。具体的には、歯先5b部分が最も早く冷
却され、歯底5cに近づくにつれて冷却速度は遅くな
り、歯底5cに近づくにつれて冷却速度は遅くなり、歯
底5c部分は最も遅く冷却されることなる。この傾向は
焼入冷却時における歯車5の回転速度が早くなればなる
ほど顕著に現われる。つまり、歯車5の回転速度が大き
くなればなるほど噴射冷却水は歯先5b部分及び歯側面
5dにて弾き飛ばされる量及び遠心力にて飛散される量
が多くなるので、歯先5b部分と歯底5c部分の冷却速
度の差が大きくなるのである。
That is, in the prior art, since the gear 5 which is the object to be hardened is rotated at a required rotational speed during the injection of the cooling liquid, the cooler injected in the diametrical direction of the gear 5 is a gear. Although it often hits the tooth tip 5b of 5,
The actual condition is that it does not hit the tooth bottom 5c very well. Therefore, in the tooth tip 5b portion, the tooth bottom 5c portion, and the tooth side surface 5d portion in the middle thereof, the cooling rates of the heating surfaces are different from each other. Specifically, the tooth tip 5b is cooled earliest, the cooling rate becomes slower as it approaches the tooth root 5c, the cooling rate becomes slower as it approaches the tooth root 5c, and the tooth root 5c portion is cooled the slowest. Become. This tendency becomes more remarkable as the rotation speed of the gear 5 during quenching and cooling increases. That is, as the rotational speed of the gear 5 increases, the amount of jetted cooling water that is repelled at the tip 5b and the tooth side surface 5d and the amount that is scattered by centrifugal force increases, so that the tip 5b and the tooth 5b The difference in the cooling rate of the bottom 5c portion becomes large.

【0010】そこで、冷却速度の差をなくすためには、
冷却液の噴射方向を偏倚させて回転中の歯車5の歯底5
cに直角に当てるようにすることが考えられるが、遠心
力の存在等にて歯先5b部分よりも歯底5c部分の冷却
速度が遅くなる現象をなくすことはできないのが実状で
ある。
Therefore, in order to eliminate the difference in cooling rate,
The tooth bottom 5 of the gear 5 that is rotating by biasing the injection direction of the cooling liquid
Although it may be considered to apply it at a right angle to c, the fact that the cooling rate of the tooth bottom 5c portion becomes slower than the tooth tip 5b portion due to the presence of centrifugal force or the like cannot be eliminated.

【0011】しかして、歯先5bの冷却速度が早く、歯
底5cの冷却速度がそれよりも遅い場合には、加熱面の
不均一冷却に伴い体積変化が不均一となり、歯先5b部
分は歯先5c部分よりも早く収縮しようとする。また、
各部分の加熱表面はその内部部分よりも早く収縮しよう
とする。しかし、この収縮は遅く、冷却される部分によ
って妨げられる。かくして、急冷のための不均一冷却に
よって熱応力が発生する。
However, when the cooling rate of the tooth tip 5b is fast and the cooling rate of the tooth bottom 5c is slower than that, the volume change becomes non-uniform due to the uneven cooling of the heating surface, and the tooth tip 5b portion is Attempts to shrink faster than the tip 5c. Also,
The heated surface of each part tends to shrink faster than its inner part. However, this shrinkage is slow and is hindered by the cooled parts. Thus, non-uniform cooling for quenching causes thermal stress.

【0012】また、焼入れによる応力は、急冷による組
織変化(マルテンサイト化)、すなわち変態による変態
応力が発生する。この発生原因は、オーステナイトとそ
の分解生成物の比容積が異なること、及び変態が不均一
冷却のために異なった時期に発生することにより誘発さ
れる。この焼入れによる内部応力(熱応力及び変態応
力)が鋼の降伏点を越すと塑性変形を生じる。これが、
変形や曲りであり、内部応力が鋼の引張強さよりも大き
くなると、必然的に割れを生じる。しかし、焼入れによ
る内部応力の発生は防ぎようがないのが現状である。
As for the stress due to quenching, a structural change (martensite formation) due to rapid cooling, that is, a transformation stress due to transformation occurs. This cause is induced by the different specific volumes of austenite and its decomposition products, and the transformation occurring at different times due to non-uniform cooling. When the internal stress (thermal stress and transformation stress) due to this quenching exceeds the yield point of steel, plastic deformation occurs. This is,
It is deformation or bending, and when the internal stress becomes larger than the tensile strength of steel, inevitably cracking occurs. However, the current situation is that the generation of internal stress due to quenching cannot be prevented.

【0013】一方、従来の歯車の焼入方法における噴射
冷却においては、歯面5aの各部における冷却速度が異
なり、しかも噴射冷却液は無作為(アットランダム)に
歯面に当るため、不均一な冷却となり、冷却の各瞬間に
おける内部応力分布は複雑なものとなっていると推察さ
れる。従って、内部応力分布は全く把握できず、焼割れ
や焼歪(変形)等の防止対策は非常に難しい。
On the other hand, in the injection cooling in the conventional gear quenching method, the cooling rate at each part of the tooth surface 5a is different, and the injection cooling liquid hits the tooth surface randomly (at random), so that it is uneven. It becomes cooling, and it is assumed that the internal stress distribution at each moment of cooling is complicated. Therefore, the internal stress distribution cannot be grasped at all, and it is very difficult to prevent quenching cracks and strains (deformations).

【0014】かくして、表面焼入れプロセスで発生する
内部応力は亀裂の発生原因となるが、不均一な冷却は亀
裂の発生を助長する。従って、焼入冷却として噴射冷却
方法を採用する場合には、個々の噴射液が被焼入体の全
面に行きわたるようにして冷却の均一性を保つことが必
要である。しかし、歯車の歯面のように複雑な表面に焼
入れを施す際には、従来の焼入方法における噴射冷却で
は、歯面の均一冷却ができず、亀裂を発生するおそれが
多分になる。それにも拘わらず、従来では、均一冷却を
行なうには回転状態の下で歯車を噴射冷却するのが望ま
しいとの誤った認識に基いて焼入冷却を行っているのが
実状である。
Thus, while the internal stresses generated in the surface quenching process cause cracking, the uneven cooling promotes cracking. Therefore, when adopting the jet cooling method as the quenching cooling, it is necessary to keep the cooling uniformity by spreading the individual jetting liquids over the entire surface of the object to be quenched. However, when quenching a complex surface such as the tooth flank of a gear, injection cooling in the conventional quenching method cannot uniformly cool the tooth flank, and there is a possibility that cracks may occur. Nevertheless, in the conventional practice, quenching cooling is performed based on the false recognition that it is desirable to jet-cool a gear under a rotating state in order to perform uniform cooling.

【0015】本発明は、上述の如き実状に鑑みてなされ
たものであって、その目的は、焼入冷却時における複雑
な内部応力の発生を抑制でき、焼割れや焼歪を防止でき
るような歯車の焼入方法を提供することにある。
The present invention has been made in view of the above situation, and an object thereof is to prevent generation of complicated internal stress during quenching and cooling and to prevent quench cracking and strain. It is to provide a method of quenching a gear.

【0016】[0016]

【課題を解決するための手段】上述の目的を達成するた
めに、本発明では、焼入れを施すべき歯車をその軸心を
中心に回転させた状態で歯面を所要温度に加熱し、次い
で前記歯車の回転を停止せしめて前記歯車の各々の歯底
に冷却液をそれぞれ噴射することにより、前記冷却液を
前記歯車の歯底から歯先に沿って流して焼入冷却するよ
うにしている。
In order to achieve the above object, the present invention heats a tooth surface to a required temperature in a state in which a gear to be hardened is rotated about its axis, and then the above-mentioned By stopping the rotation of the gears and injecting the cooling liquid into the bottoms of the gears, the cooling liquids are made to flow from the bottoms of the gears along the tips of the gears for quenching and cooling.

【0017】[0017]

【実施例】以下、本発明の一実施例に付き図1〜図7を
参照して説明する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

【0018】図1〜図3は本発明に係る歯車の焼入方法
を実施するのに用いられる焼入装置10を示すものであ
って、この焼入装置10は、円環状の高周波誘導加熱コ
イル11と、このコイル11に高周波電流を供給する電
源12と、被焼入体である歯車13を保持して回転駆動
する治具14と、高周波誘導加熱コイル11に冷却液を
供給する複数本の冷却液供給パイプ15とを備えてい
る。
1 to 3 show a quenching apparatus 10 used for carrying out the method for quenching a gear according to the present invention. The quenching apparatus 10 is an annular high frequency induction heating coil. 11, a power supply 12 for supplying a high-frequency current to the coil 11, a jig 14 for holding and rotating the gear 13 which is a material to be hardened, and a plurality of coils for supplying a cooling liquid to the high-frequency induction heating coil 11. A cooling liquid supply pipe 15 is provided.

【0019】上述の高周波誘導加熱コイル11は、図1
に示すように、互いに対向する一対のリード部16a,
16bを有しており、これらのリード部16a,16b
の間には絶縁板16cが介在されている。そして、リー
ド部16a,16bを通して電源12から高周波誘導加
熱コイル11に高周波電流が供給されるように構成され
ている。
The high frequency induction heating coil 11 described above is shown in FIG.
, A pair of lead portions 16a facing each other,
16b, and these lead portions 16a, 16b
An insulating plate 16c is interposed between them. Then, a high-frequency current is supplied from the power supply 12 to the high-frequency induction heating coil 11 through the lead portions 16a and 16b.

【0020】また、円環状の高周波誘導加熱コイル11
は、図1及び図2示す如く、その内部が中空の箱形の断
面形状に成形されており、その中空部分が冷却液通路1
7となされている。そして、高周波誘導加熱コイル11
は外周壁11aよりも内周壁11bの方が肉厚に構成さ
れており、肉厚状の内周壁11bには多数の冷却液噴射
孔18が設けられている。なお、これらの噴射孔18
は、図3に明示するように、コイル幅方向及び内周方向
に沿って縦横にそれぞれ所定間隔A及びBで一列に配置
されている。さらに、コイル11の周方向における噴射
孔18の間隔Bは、被焼入体である歯車13の歯部のピ
ッチP(図1参照)に応じて設定されており、後述の如
く、歯車13の歯底13cにコイル幅方向の列の噴射孔
18が配応配置されるようになっている。
The annular high frequency induction heating coil 11
As shown in FIG. 1 and FIG. 2, the inside thereof is formed into a hollow box-shaped cross-sectional shape, and the hollow portion has a cooling liquid passage 1
It is said to be 7. And the high frequency induction heating coil 11
The inner peripheral wall 11b is thicker than the outer peripheral wall 11a, and a large number of cooling liquid injection holes 18 are provided in the thick inner peripheral wall 11b. In addition, these injection holes 18
As shown in FIG. 3, they are arranged in a row at predetermined intervals A and B along the coil width direction and the inner circumferential direction at predetermined intervals A and B, respectively. Further, the interval B of the injection holes 18 in the circumferential direction of the coil 11 is set according to the pitch P (see FIG. 1) of the tooth portion of the gear 13 that is the object to be hardened, and as described later, The injection holes 18 in the coil width direction are arranged correspondingly on the tooth bottom 13c.

【0021】また、高周波誘導加熱コイル11の外周壁
11aの複数箇所には冷却液供給パイプ15が接続さ
れ、これらのパイプ15を通して高周波誘導加熱コイル
11の通路17に冷却液が供給されて噴射孔18から歯
車13の歯底13cに対してほぼ直角状に噴射されるよ
うになっている。
Further, cooling liquid supply pipes 15 are connected to a plurality of locations on the outer peripheral wall 11a of the high frequency induction heating coil 11, and the cooling liquid is supplied to the passages 17 of the high frequency induction heating coil 11 through these pipes 15 to inject holes. It is configured to be sprayed from 18 at a substantially right angle to the tooth bottom 13 c of the gear 13.

【0022】そして、高周波誘導加熱コイル11と同心
状に治具14が配置され、この治具14上に歯車13が
載置された状態で、その軸心を中心に回転駆動されるよ
うに構成されている。
A jig 14 is arranged concentrically with the high frequency induction heating coil 11, and a gear 13 is placed on the jig 14 so that the jig 14 is rotationally driven about its axis. Has been done.

【0023】次に、上述の焼入装置10を用いて歯車1
3の歯面13aを焼入れする際の動作に付き説明する。
まず、被焼入体である歯車13を治具14上に載置し、
治具14を移動させることによって歯車13を高周波誘
導加熱コイル11の中心部に同軸状に配置する。しかる
後に、治具14を回転駆動することによって歯車13を
その軸心を中心に回転させると共に、高周波誘導加熱コ
イル11に電源12から高周波電流を供給して歯車13
の歯面13aを高周波誘導加熱する。そして、回転状態
での均一加熱によって歯面13aが所要の焼入温度に達
した時点で、高周波誘導加熱への通電を停止する。これ
と同時に、治具13の回転を急停止して歯車13を静止
状態にすると共に、図外の位置決め機構の作用にて歯車
13の各歯底13cに高周波誘導加熱コイル11の噴射
孔18を対応させた状態にする。すなわち、歯車13の
各々の歯底13cに高周波誘導加熱コイル11の幅方向
に一列状の配列された複数(例えば3つ)の噴射孔18
をそれぞれ対応配置せしめた状態で歯車13を回転停止
せしめて静止させる。
Next, the gear 1 is manufactured by using the quenching apparatus 10 described above.
The operation when quenching the tooth flank 13a of No. 3 will be described.
First, the gear 13 which is the material to be hardened is placed on the jig 14,
By moving the jig 14, the gear 13 is coaxially arranged at the center of the high frequency induction heating coil 11. After that, the gear 13 is rotated about its axis by rotationally driving the jig 14, and a high-frequency current is supplied from the power supply 12 to the high-frequency induction heating coil 11 to cause the gear 13 to rotate.
The tooth surface 13a of is heated by high frequency induction. Then, when the tooth surface 13a reaches the required quenching temperature by the uniform heating in the rotating state, the energization to the high frequency induction heating is stopped. At the same time, the rotation of the jig 13 is suddenly stopped to bring the gear 13 into a stationary state, and an injection hole 18 of the high frequency induction heating coil 11 is formed in each tooth bottom 13c of the gear 13 by the action of a positioning mechanism (not shown). Make them correspond. That is, a plurality of (eg, three) injection holes 18 arranged in a row in the width direction of the high-frequency induction heating coil 11 are provided on the tooth bottoms 13 c of the gears 13.
The gears 13 are stopped and stopped while the gears 13 are arranged in correspondence with each other.

【0024】次いで、冷却液を供給パイプ15及び通路
17に次順供給し、噴射孔18から所要の圧力、流量、
液温の冷却液を歯車13の歯底13cに向けて噴射させ
る。そして、所要の冷却条件により所要時間に亘り冷却
した後に、初期の冷却条件と異なる冷却条件、すなわち
冷却能の小さい条件により冷却することにより、焼入作
業を終了する。
Next, the cooling liquid is sequentially supplied to the supply pipe 15 and the passage 17, and the required pressure and flow rate are supplied from the injection holes 18.
The cooling liquid having the liquid temperature is jetted toward the tooth bottom 13c of the gear 13. Then, after cooling for a required time under the required cooling condition, the quenching work is completed by cooling under a cooling condition different from the initial cooling condition, that is, a condition having a small cooling capacity.

【0025】以上の如き本発明に係る焼入方法によれ
ば、次のような利点がある。すなわち、均一加熱した歯
車13を静止させて、従来では最も冷却が不完全(冷却
速度が遅い)とされる歯底13c部分に向って冷却液を
噴射すると、冷却液は歯底13c部分から歯側面13d
をつたわって歯先13b部分に流れ、この歯先13b部
分が最後に冷却される。しかし、歯底13cから歯先1
3bに向って質量は徐々に小さくなるため、歯底13c
に噴射される冷却液の圧力、流量、液温を調整すること
により、歯面13a全体を均一な冷却速度で冷却するこ
とは容易に可能である。その理由は、歯車13が静止さ
れ、冷却液の噴射箇所が定められているので、冷却液の
流れがアットランダムでなくしかも流れる方向の把握が
できるからである。これにより、歯面13a全体を均一
に、或いは所定の冷却速度の変化をもって冷却すること
ができ、変形を最小限に抑えることができ、寸法精度の
高い焼入処理が可能となる。
The quenching method according to the present invention as described above has the following advantages. That is, when the uniformly heated gear 13 is stopped and the cooling liquid is sprayed toward the tooth bottom 13c portion where cooling is incomplete (the cooling rate is slow) in the related art, the cooling fluid is fed from the tooth bottom 13c portion. Side surface 13d
Flow to the tooth tip 13b portion, and this tooth tip 13b portion is finally cooled. However, from the tooth bottom 13c to the tooth tip 1
Since the mass gradually decreases toward 3b, the tooth bottom 13c
It is possible to easily cool the entire tooth surface 13a at a uniform cooling rate by adjusting the pressure, the flow rate, and the liquid temperature of the cooling liquid injected into the. The reason is that since the gear 13 is stationary and the injection position of the cooling liquid is determined, the flow of the cooling liquid is not at random and the flowing direction can be grasped. As a result, the entire tooth surface 13a can be cooled uniformly or with a predetermined change in cooling rate, deformation can be minimized, and quenching processing with high dimensional accuracy can be performed.

【0026】また、所要圧力、流量の冷却条件により所
要時間急冷した後に、この冷却条件で常温まで冷し切ら
ずに、より緩やかな冷却条件に切り換えて冷却すること
により、変形及び焼割れの発生を防止できる。
Further, after rapid cooling for a required time under the cooling conditions of required pressure and flow rate, deformation and quench cracking occur by switching to a more gradual cooling condition without cooling down to normal temperature under this cooling condition. Can be prevented.

【0027】このような作用効果を確認するために、以
下に示す条件で実験を行なった。
In order to confirm such an effect, an experiment was conducted under the following conditions.

【0028】具体例 1.歯車の種類:平歯車 2.材質:S−53C 3.外径(歯先円直径):87mm 4.ピッチ円直径:84mm 5.歯幅:10mm 6.歯数:56 7.モジュール:1.5焼入条件 (1)予熱(高周波誘導加熱コイル) (a)周波数:3kHz (b)出力:170kW (c)加熱時間:2.8秒 (d)歯車の回転数:250r.p.m. (2)本加熱(高周波誘導加熱コイル) (a)周波数:400kHz (b)入力:200kW (c)加熱時間:0.15秒 (d)歯車の回転数:250r.p.m. (3)冷却 (A)第1冷却条件 (a)冷却液:ユーコンクエンチャント(10%) (b)液温:30℃ (c)流量:60 l/min (d)圧力:4kg/cm2 (e)冷却時間:2秒 (B)第2冷却条件 (a)冷却液:ユーコンクエンチャント(10%) (b)液温:30℃ (c)流量:30 l/min (d)圧力:3kg/cm2 (e)冷却時間:6秒 Concrete Example 1. Gear type: Spur gear 2. Material: S-53C 3. Outer diameter (diameter of tip circle): 87 mm 4. Pitch circle diameter: 84 mm 5. Tooth width: 10 mm 6. Number of teeth: 56 7. Module: 1.5 Quenching condition (1) Preheating (high frequency induction heating coil) (a) Frequency: 3 kHz (b) Output: 170 kW (c) Heating time: 2.8 seconds (d) Gear rotation speed: 250 r. p. m. (2) Main heating (high frequency induction heating coil) (a) Frequency: 400 kHz (b) Input: 200 kW (c) Heating time: 0.15 seconds (d) Gear rotation speed: 250 r. p. m. (3) Cooling (A) First cooling condition (a) Coolant: Yukon quenchant (10%) (b) Liquid temperature: 30 ° C (c) Flow rate: 60 l / min (d) Pressure: 4 kg / cm 2 (E) Cooling time: 2 seconds (B) Second cooling condition (a) Coolant: Yukon quenchant (10%) (b) Liquid temperature: 30 ° C (c) Flow rate: 30 l / min (d) Pressure: 3 kg / cm 2 (e) Cooling time: 6 seconds

【0029】上記の条件下で焼入処理された歯車の各部
の冷却速度並びに断面硬度を測定したところ、図4〜図
7に示す如き結果を得た。図4に示す測定結果から、歯
底13cが歯先13bよりも早く冷却されていることが
確認された。また、図5〜図7に示す測定結果から、歯
面13aの表面には硬度800(Hv)以上の充分な硬
度の硬化層が得られると共に、歯車の各部における表面
硬度がほぼ均一となっていることが確認された。
When the cooling rate and the cross-section hardness of each part of the gear that had been subjected to the quenching treatment under the above conditions were measured, the results shown in FIGS. 4 to 7 were obtained. From the measurement results shown in FIG. 4, it was confirmed that the tooth bottom 13c was cooled earlier than the tooth tip 13b. Further, from the measurement results shown in FIGS. 5 to 7, a hardened layer having a hardness of 800 (Hv) or more is obtained on the surface of the tooth surface 13a, and the surface hardness of each portion of the gear is substantially uniform. Was confirmed.

【0030】さらに、本例の方法によって焼入処理した
歯車13の歯面13a、及び、歯車を回転させながら噴
射冷却する従来の方法により焼入処理した歯車の歯面の
表面の残留応力を測定したところ表1に示す結果を得
た。なお、表1における測定箇所(a),(b),
(c),(d)は90°の角度間隔を順次隔てた箇所に
ある歯面(歯底又は歯先)である。
Further, the residual stress on the tooth surface 13a of the gear 13 hardened by the method of this example and on the tooth surface of the gear hardened by the conventional method of jet cooling while rotating the gear is measured. Then, the results shown in Table 1 were obtained. The measurement points (a), (b) in Table 1
(C) and (d) are tooth surfaces (tooth roots or tooth tips) that are sequentially spaced at 90 ° angular intervals.

【0031】[0031]

【表1】 [Table 1]

【0032】表1から明らかなように、本例の方法によ
って、得られた歯車13の歯底13cにおける残留応力
は従来方法によるものに比べて充分に大きな値の圧縮応
力であり、従って疲労強度の強い歯車13であることが
確認された。
As is apparent from Table 1, the residual stress at the tooth bottom 13c of the gear 13 obtained by the method of this example is a compressive stress of a sufficiently large value as compared with that by the conventional method, and therefore the fatigue strength. It was confirmed that the gear 13 had a strong strength.

【0033】また、本例によれば、焼割れや変形が殆ん
どない寸法精度の高い歯車が得られた。
Further, according to this example, a gear having high dimensional accuracy with almost no quench cracking or deformation was obtained.

【0034】以上、本発明の一実施例に付き述べたが、
本発明は、既述の実施例に限定されるものではなく、本
発明の技術的思想に基いて各種の変形及び変更が可能で
ある。例えば、本発明は平歯車に限らずヘリカルギヤ等
の各種の歯車の焼入方法に適用可能である。なお、この
場合には、噴射孔18の配列は各歯車の歯底に合せて設
定すればよい。また、高周波誘導加熱コイル11の他に
既述の如き冷却液噴射孔を有する冷却環を配置するよう
にしてもよい。さらに、加熱手段としては、高周波誘導
加熱コイルに限らず、加熱炉を用いるようにしてもよ
い。
The above is a description of one embodiment of the present invention.
The present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention. For example, the present invention is applicable not only to spur gears but also to quenching methods for various gears such as helical gears. In this case, the arrangement of the injection holes 18 may be set according to the tooth bottom of each gear. In addition to the high frequency induction heating coil 11, a cooling ring having a cooling liquid injection hole as described above may be arranged. Further, the heating means is not limited to the high frequency induction heating coil, but a heating furnace may be used.

【0035】[0035]

【発明の効果】以上の如く、本発明は、歯車の歯面を所
要温度に加熱した後に歯車の回転を停止せしめ、静止状
態の歯車の歯底に冷却液を噴射して歯先側に流すように
したものであるから、質量が最も大きく最も冷却されに
くい歯底の冷却が促進されると共に、質量が最も小さ
く、最も冷却されやすい歯先の冷却が抑制されることと
なる結果、歯車の歯面の均一冷却が可能となる。また、
歯車は静止状態の下で冷却液が噴射されるので、冷却液
の噴射箇所はアットランダムでなく歯底に確実に当てる
ことができ、冷却液の飛散等を生じることなく歯面に沿
って流れ渡るので、歯面に複雑な残留応力が生じること
がなく、焼割れや変形の発生を防止できる。さらに、冷
却液の噴射圧力、流量、液温等の条件を調節することに
より、歯面の各部分における冷却速度を任意に調整でき
るため、均一な或いは一様に変化する理想的な焼入硬化
層パターンを得ることができる。
As described above, according to the present invention, after the tooth surface of the gear is heated to the required temperature, the rotation of the gear is stopped, and the cooling liquid is jetted to the tooth bottom of the gear in the stationary state to flow to the tooth tip side. Therefore, the cooling of the tooth bottom, which has the largest mass and is the most difficult to cool, is promoted, and the cooling of the tooth tip, which has the smallest mass and is most easily cooled, is suppressed. Uniform cooling of the tooth surface is possible. Also,
Coolant is sprayed on the gear under stationary condition, so the sprayed spot of coolant can be applied to the bottom of the tooth without being random, and the coolant flows along the tooth surface without scattering. Since it crosses over, complicated residual stress does not occur on the tooth surface, and it is possible to prevent the occurrence of quenching cracks and deformation. Furthermore, by adjusting the conditions such as the injection pressure, flow rate, and liquid temperature of the cooling liquid, the cooling rate at each part of the tooth surface can be adjusted arbitrarily, so ideal quench hardening that is uniform or changes uniformly. A layer pattern can be obtained.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明に係る歯車の焼入方法を実施するための
焼入装置の平面図である。
FIG. 1 is a plan view of a quenching device for carrying out a gear quenching method according to the present invention.

【図2】前記焼入装置の断面図である。FIG. 2 is a cross-sectional view of the quenching device.

【図3】高周波誘導加熱装置の要部断面図である。FIG. 3 is a cross-sectional view of a main part of a high frequency induction heating device.

【図4】本発明の方法を実施した場合の歯車の歯底及び
歯先の冷却速度を示すグラフである。
FIG. 4 is a graph showing cooling rates of tooth bottoms and tips of gears when the method of the present invention is carried out.

【図5】本発明の方法により得られた歯車の歯先の断面
硬度分布を示すグラフである。
FIG. 5 is a graph showing the cross-sectional hardness distribution of the addendum of the gear obtained by the method of the present invention.

【図6】本発明の方法により得られた歯車の歯側面の断
面硬度分布を示すグラフである。
FIG. 6 is a graph showing the cross-sectional hardness distribution on the tooth flanks of the gear obtained by the method of the present invention.

【図7】本発明の方法により得られた歯車の歯側面と歯
底との境界箇所(R部)の断面硬度分布を示すグラフで
ある。
FIG. 7 is a graph showing a cross-sectional hardness distribution at the boundary portion (R portion) between the tooth flank and the tooth bottom of the gear obtained by the method of the present invention.

【図8】従来の歯車の焼入方法を実施するための焼入装
置の平面図である。
FIG. 8 is a plan view of a quenching device for carrying out a conventional gear quenching method.

【図9】前記焼入装置の断面図である。FIG. 9 is a cross-sectional view of the quenching device.

【図10】高周波誘導加熱コイルの要部断面図である。FIG. 10 is a cross-sectional view of a main part of a high frequency induction heating coil.

【図11】噴射冷却及びズブ冷却による冷却速度をそれ
ぞれ示すグラフである。
FIG. 11 is a graph showing cooling rates by jet cooling and zub cooling, respectively.

【図12】噴射における流量と冷却曲線との関係を示す
グラフである。
FIG. 12 is a graph showing a relationship between a flow rate in injection and a cooling curve.

【図13】従来の方法によって焼入冷却する場合の歯車
の歯底及び歯先の冷却速度を示すグラフである。
FIG. 13 is a graph showing the cooling rates of the tooth bottoms and tips of gears when quenching and cooling by a conventional method.

【符号の説明】[Explanation of symbols]

10 高周波焼入装置 11 高周波誘導加熱コイル 13 歯車 13a 歯面 13b 歯先 13c 歯底 13d 歯側面 14 治具 15 冷却液供給パイプ 17 冷却液通路 18 冷却液噴射孔 10 induction hardening apparatus 11 induction heating coil 13 gear 13a tooth surface 13b tooth tip 13c tooth bottom 13d tooth side surface 14 jig 15 cooling fluid supply pipe 17 cooling fluid passage 18 cooling fluid injection hole

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】 焼入れを施すべき歯車をその軸心を中心
に回転させた状態で歯面を所要温度に加熱し、次いで前
記歯車の回転を停止せしめて前記歯車の各々の歯底に冷
却液をそれぞれ噴射することにより、前記冷却液を前記
歯車の歯底から歯先に沿って流して焼入冷却するように
したことを特徴とする歯車の焼入方法。
1. A gear to be quenched is heated to a required temperature in a state in which the gear is rotated about its axis, and then rotation of the gear is stopped so that a cooling liquid is applied to the bottom of each tooth of the gear. A quenching method for gears, characterized in that the cooling liquid is caused to flow from the bottom of the gears along the tips of the gears for quenching and cooling.
【請求項2】 前記歯車の歯底に噴射される冷却液の噴
射圧力、流量及び液温を調節することによって、歯底部
分及び歯先部分の冷却速度を調整しつつ焼入冷却するよ
うにしたことを特徴とする請求項1に記載の歯車の焼入
方法。
2. The quenching cooling is performed while adjusting the cooling speed of the tooth bottom portion and the tooth tip portion by adjusting the injection pressure, the flow rate and the liquid temperature of the cooling fluid injected to the tooth bottom of the gear. The method for quenching a gear according to claim 1, wherein:
【請求項3】 前記冷却液の噴射圧力、流量、液温及び
冷却時間等の冷却条件を2工程以上に変えながら前記歯
車の歯面の冷却速度を調整しつつ焼入冷却するようにし
たことを特徴とする請求項1に記載の歯車の焼入方法。
3. Quenching cooling while adjusting the cooling speed of the tooth flanks of the gear while changing the cooling conditions such as the injection pressure of the cooling liquid, the flow rate, the liquid temperature, and the cooling time in two or more steps. The method for quenching a gear according to claim 1, wherein:
JP11923491A 1991-04-23 1991-04-23 Gear quenching method Expired - Fee Related JP3230822B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11923491A JP3230822B2 (en) 1991-04-23 1991-04-23 Gear quenching method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11923491A JP3230822B2 (en) 1991-04-23 1991-04-23 Gear quenching method

Publications (2)

Publication Number Publication Date
JPH06122925A true JPH06122925A (en) 1994-05-06
JP3230822B2 JP3230822B2 (en) 2001-11-19

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013532233A (en) * 2010-07-02 2013-08-15 アクティエボラゲット・エスコーエッフ Machine component and surface hardening method
CN106755827A (en) * 2016-12-25 2017-05-31 重庆润跃机械有限公司 Gear quenching anti-splash device
CN113293265A (en) * 2021-05-31 2021-08-24 湖州金鼎精密科技有限公司 Quenching device for duplicate gear

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013532233A (en) * 2010-07-02 2013-08-15 アクティエボラゲット・エスコーエッフ Machine component and surface hardening method
CN106755827A (en) * 2016-12-25 2017-05-31 重庆润跃机械有限公司 Gear quenching anti-splash device
CN113293265A (en) * 2021-05-31 2021-08-24 湖州金鼎精密科技有限公司 Quenching device for duplicate gear

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