JP3593948B2

JP3593948B2 - Method for producing tooth-shaped forged product having tooth-shaped surface in cylindrical part

Info

Publication number: JP3593948B2
Application number: JP2000119235A
Authority: JP
Inventors: 二三雄釜崎; 巌水谷
Original assignee: Aichi Steel Corp
Current assignee: Aichi Steel Corp
Priority date: 2000-04-20
Filing date: 2000-04-20
Publication date: 2004-11-24
Anticipated expiration: 2020-04-20
Also published as: JP2001300682A

Description

【０００１】
【技術分野】
本発明は，筒状部に歯形面を有する歯形鍛造品を一体的に製造する方法に関する。
【０００２】
【従来技術】
例えば自動車部品として，図１０に示すごとく，パーキングギア部材９１とドリブンギア部材９２とを同軸上に配置したカウンタードリブンギア９が使用されている。
従来，この部品を製造するに当たっては，図９（ａ）（ｂ）に示すごとく，まず熱間鍛造にてパーキングギア部材９１とドリブンギア部材９２をそれぞれ別々に作製する。
【０００３】
次いで，図９（ｃ）（ｄ）に示すごとく，パーキングギア部材９１の外周部面に凹凸形状を有する歯形面９１５を機械加工により形成する。また，ドリブンギア部材９２の軸穴部９２４の内周面を機械加工する。
次いで，図９（ｅ）に示すごとく，ドリブンギア部材９２とパーキングギア部材９１とを圧入嵌合させると共に溶接して一体化する。
その後，図１０に示すごとく，仕上げの機械加工を行って，パーキングギア部材９１とドリブンギア部材９２とを一体的に有するカウンタードリブンギア９が得られる。
【０００４】
このように，上記カウンタードリブンギア９の場合には，円筒状のパーキングギア部材９１に予め歯形形状を機械加工により形成し，その後一体化すべきドリブンギア部材９２と接合する製造方法が採用されている。
このような製造方法は，カウンタードリブンギアに限らず，ベース部に立設した筒状部を有しその内周面あるいは外周面に歯形形状を有する部品を製造する場合に適用される。
【０００５】
【解決しようとする課題】
しかしながら，上記従来の製造方法には次の問題がある。
即ち，上記製造方法では，上記筒状部への歯形面の形成を機械加工により行う必要があり，工程が複雑である。またそのため，コスト高となる。また，筒状部とベース部との接合を圧入，溶接等により行うため，その接合部分の強化を行う必要がある。そのため，軽量化が困難である。
【０００６】
この対策として，上記ベース部と筒状部とを一体的に鍛造により製造する方法が考えられる。この場合，熱間鍛造だけでは上記歯形面の形状を精度よく仕上げることが困難であるので，熱間鍛造後に冷間鍛造を行うことが必要となる。しかし，従来においては，冷間鍛造を行っても上記歯形面の形状を精度よく仕上げることは困難であり，欠肉や座屈といった不良が発生する。また，冷間鍛造時の形状精度を向上させるために高い加工度を加えようとすると，冷間鍛造用の金型が荷重に耐えきれずに破損してしまう場合もあった。それ故，従来においては，上記筒状部に鍛造によって歯形面を精度よく形成することは不可能であった。
【０００７】
本発明は，かかる従来の問題点に鑑みてなされたもので，筒状部への歯形面の形成を，鍛造により精度よく行うことができる，筒状部に歯形面を有する歯形鍛造品の製造方法を提供しようとするものである。
【０００８】
【課題の解決手段】
請求項１の発明は，ベース部から立設された筒状部を有すると共にその外周面又は内周面に凹凸形状を有する歯形面を設けてなる歯形鍛造品を製造する方法であって，
素材を熱間鍛造することにより，上記ベース部と上記筒状部を形成すると共に，該筒状部の外周面又は内周面に凹凸形状を有する歯形面を設け，かつ，該歯形面の凸部の裏側面には，上記凸部の突出方向に向けて窪んだ窪部を設け，
その後，上記窪部を拘束しない状態で上記筒状部に冷間鍛造を加えることを特徴とする筒状部に歯形面を有する歯形鍛造品の製造方法にある。
【０００９】
本発明において最も注目すべきことは，上記熱間鍛造時において，上記窪部を有する筒状部を設け，その後，上記窪部を拘束しない状態で上記筒状部に冷間鍛造を加えることである。
上記歯形面の凸部の形状としては，矩形状，台形状，三角形状，その他，公知の種々の形状を適用できる。また，上記窪部の形状としても，種々の形状を適用できる。
【００１０】
次に，本発明の作用につき説明する。
本発明においては，まず，上記素材を熱間鍛造して上記ベース部と筒状部とを一体的に設けると共に，該筒状部に上記歯形面を設ける。このとき，上記のごとく，該歯形面の凸部の裏側面には，上記凸部の突出方向に向けて窪んだ窪部を設ける。この窪部の形成により，その後の冷間鍛造において非常に精度の高い加工をを行うことができる。
【００１１】
即ち，上記冷間鍛造においては，熱間鍛造によって形成した上記歯形面の窪部を拘束しない状態で加工する。より具体的には，冷間鍛造に用いる金型の歯形面の裏面に対するキャビティは，上記窪部に当接しないように設計しておく。これにより，上記歯形面を冷間鍛造する際に，過剰の荷重が付与された場合においても，それが上記窪部において開放される。そのため，従来のような金型の破損を心配することなく，上記歯形面に十分に高い荷重を加えることができる。それ故，上記歯形面の凸部及び凹部は，高い荷重によってキャビティ形状に沿った所望の形状に成形され，荷重の過剰分は上記窪部を増肉させる現象によって開放される。
【００１２】
従って，この製造方法を用いれば，歯形面を有する筒状部とベース部との一体成形を容易に行うことができ，しかも，歯形面の形状を非常に高い精度で形成することができる。そのため，従来行っていた歯形面形成のための機械加工は不要となり工程合理化及びコストダウンを図ることができる。
【００１３】
次に，請求項２の発明のように，上記窪部は断面形状が円弧状であることが好ましい。この場合には，窪部の表面を円弧状の滑らかな形状とすることにより，鍛造による形成を容易にすることができると共に，応力集中等を回避することができる。
【００１４】
また，請求項３の発明のように，上記冷間鍛造においては，上記筒状部に対するキャビティの軸方向の深さをＤ，冷間鍛造前の上記筒状部の高さをＨとしたとき，Ｄ＜Ｈであり，かつ，（Ｈ−Ｄ）／Ｈ≧０．１であることが好ましい。Ｄ＜Ｈとすることにより上記筒状部に軸方向の荷重を容易に付与することができる。そして，上式（Ｈ−Ｄ）／Ｈを０．１以上となるように加工度を高めた場合には，特に歯形面の形状精度を向上させることができ，この場合においても上記窪部を設けた場合の効果を有効に発揮して金型を破損することなくスムーズな成形を行うことができる。
【００１５】
また，請求項４の発明のように，上記筒状部の軸方向の高さをＡ，上記筒状部の先端における上記凹部の厚みをＢとした場合，Ｂ／Ａ≦０．３の関係が成り立つ場合において，特に有効である。即ち，上記Ｂ／Ａ＞０．３の場合には，冷間鍛造時の座屈や欠肉現象が起こりにくいが，Ｂ／Ａ≦０．３の場合には，これらの不良が発生しやすい傾向にある。この場合においても，上記窪部を設けることによって，冷間鍛造時の上記不具合を容易に回避することができる。
【００１６】
また，請求項５の発明のように，上記歯形鍛造品は，円盤状の上記ベース部と，該ベース部の中央部分に配設され内面に軸穴を設けた軸穴部と，該軸穴部とリング状の溝を介して配設された上記筒状部としてのパーキングギア部とを一体的に有し，かつ，該パーキングギア部の外周面に凹凸形状を有する歯形面を設けてなるカウンタードリブンギア用鍛造品とすることができる。この場合には，軽量で，低コストのカウンタードリブンギア用鍛造品を製造することができる。
【００１７】
【発明の実施の形態】
実施形態例１
本発明の実施形態例にかかる筒状部に歯形面を有する歯形鍛造品の製造方法につき，図１〜図４を用いて説明する。
図１に示すごとく，本例において製造する歯形鍛造品１は，円盤状のベース部１０と，該ベース部１０の中央部分に配設され内面に軸穴１１０を設けた軸穴部１１と，該軸穴部１１とリング状溝１２を介して配設された筒状部２としてのパーキングギア部とを一体的に有する。そしてパーキングギア部２の外周面に凹凸形状を有する歯形面２０を設けてなるカウンタードリブンギア用鍛造品である。また，本例における筒状部２は，後述する図４（ａ）に示すごとく，軸方向の高さをＡ，筒状部２の先端における凹部の厚みをＢとした場合，Ｂ／Ａ≦０．３の関係にあり，比較的欠肉等の欠陥が生じやすいものである。
【００１８】
このカウンタードリブンギア用鍛造品を製造するに当たっては，まず，図１（ａ）に示すごとく，素材に複数回の熱間鍛造を施すことにより，熱鍛中間材１０１を作製する。即ち，熱間鍛造により，上記ベース部１０と筒状部（パーキングギア部）２を形成すると共に，筒状部２の外周面に凹凸形状を有する歯形面２０を設ける。このとき，歯形面２０の凸部２１の裏側面２５には，上記凸部２１の突出方向に向けて窪んだ窪部３を設ける。
【００１９】
次に，図１（ｂ）に示すごとく，冷間鍛造を施して，カウンタードリブンギア用鍛造品１を得る。
この冷間鍛造工程においては，上記窪部を拘束しない状態で上記筒状部に冷間鍛造を施す。具体的には，図２に示すごとく，冷間鍛造用の金型７として，外周側面７１は上記歯形面２０に対応してこれを成形する形状を有し，一方，内周側面７２はスムーズな円周形状を有するものを用いる。なお，本例では，筒状部２に対するキャビティの軸方向の深さをＤ（図示略），冷間鍛造前の上記筒状部２の高さをＨ（図１（ａ））としたとき，Ｄ＜Ｈであり，かつ，（Ｈ−Ｄ）／Ｈ＝０．１となるように金型７を設計した。
【００２０】
このような金型７を用いることにより，筒状部２の歯形面２０は金型７の外周側面７１に密着し，一方，筒状部２の裏側面２５と金型７１の内周側面７２とは，上記窪部３との間に空間７５を有した状態で冷間鍛造がなされる。その結果図１（ｂ）に示すごとく，上記カウンタードリブンギア用鍛造品１が得られる。
【００２１】
その後，図３に示すごとく，このカウンタードリブンギア用鍛造品１は，軸穴１１０およびベース部１０の外周面に機械加工が加えられ，製品のカウンタードリブンギア１００とされる。
【００２２】
次に，本例の作用効果につき説明する。
本例においては，上記のごとく，熱間鍛造により，上記ベース部１０と筒状部２とを一体的に設けると共に，筒状部２に歯形面２０を設ける。このとき，上記のごとく，歯形面２０の凸部２１の裏側面２５には，凸部２１の突出方向に向けて窪んだ窪部３を設ける。そして，上記冷間鍛造工程においては，熱間鍛造によって形成した歯形面２０の窪部３を拘束しない状態で加工する。
【００２３】
具体的には，図２に示すごとく，上述した金型７を用いて冷間鍛造を行う。これにより，筒状部２における歯形面２０は凸部２１，凹部２２共に金型７の外周側面７１に拘束される一方，裏側面２５においては窪部３と金型７の内周側面７２との間に間隙を維持した状態で冷間鍛造がなされる。
【００２４】
そのため，歯形面２０を冷間鍛造する際に，過剰の荷重が付与された場合においても，それが窪部３において開放される。そのため，従来のような金型の破損を心配することなく，上記（Ｈ−Ｄ）／Ｈ＝０．１となるような加工を加えることができ，歯形面２０に十分に高い荷重を加えることができる。
それ故，上記歯形面２０の凸部２１及び凹部２２は，高い荷重によって欠肉等を起こすことなくキャビティ形状に沿った所望の形状に成形され，荷重の過剰分は上記窪部を増肉させる現象によって開放される。
【００２５】
従って，この製造方法を用いれば，歯形面２０を有する筒状部２とベース部１０との一体成形を容易に行うことができ，しかも，歯形面２０の形状を非常に高い精度で形成することができる。そのため，従来行っていた歯形面形成のための機械加工は不要となり工程合理化及びカウンタードリブンギア用鍛造品１のコストダウンを図ることができる。
【００２６】
さらに，本例のカウンタードリブンギア用鍛造品１を用いれば，従来の２部品を接合して作製する場合よりも，大幅に軽量化が可能である。図４（ａ）に，本例のカウンタードリブンギア用鍛造品１を用いて作製したカウンタードリブンギア１００の断面形状を示す。一方，図４（ｂ）には，従来例に示したカウンタードリブンギア９の断面形状を示す。
【００２７】
両図の比較から明らかなように，本例のカウンタードリブンギア１００は，接合部の補強を考慮する必要がないので，軸穴部１１とパーキングギア部２との間のリング状の溝１２の部分を，従来と比べて大きくすることができ，これにより大幅な軽量化を図ることができる。
【００２８】
実施形態例２
本例は，実施形態例１と同様の製造方法を，カウンタードリブンギア用鍛造品以外の歯形鍛造品に適用した例である。
本例の歯形鍛造品１は，図５に示すごとく，中央に貫通穴５１を有する円盤状のベース部１０から立設された筒状部２を有すると共にその外周面に凹凸形状を有する歯形面２０を設けてなる歯形鍛造品である。そして，歯形面の凸２１部の裏側面２５には，上記凸部２１の突出方向に向けて窪んだ窪部３を設けてある。
【００２９】
本例の歯形鍛造品１を製造するにあたっても，実施形態例１と同様に，上記窪部３を熱間鍛造工程において形成し，その後の冷間鍛造工程において窪部３を拘束しない状態で筒状部２に冷間鍛造を加える。これにより，実施形態例１と同様に非常に優れた作用効果を得ることができる。
【００３０】
実施形態例３
本例も，実施形態例１と同様の製造方法を，カウンタードリブンギア用鍛造品以外の歯形鍛造品に適用した例である。
本例の歯形鍛造品１は，図６に示すごとく，実施形態例２の場合とベース部１０における中央部分５２の形状を変えた点が異なる歯形鍛造品である。そして，本例においても，歯形面の凸２１部の裏側面２５には，上記凸部２１の突出方向に向けて窪んだ窪部３を設けてある。
【００３１】
この場合にも，実施形態例１と同様に，上記窪部３を熱間鍛造工程において形成し，その後の冷間鍛造工程において窪部３を拘束しない状態で筒状部２に冷間鍛造を加える。これにより，実施形態例１と同様に非常に優れた作用効果を得ることができる。
【００３２】
実施形態例４
本例も，実施形態例１と同様の製造方法を，カウンタードリブンギア用鍛造品以外の歯形鍛造品に適用した例である。
本例の歯形鍛造品１は，図７に示すごとく，中央に貫通穴５１を有する円盤状のベース部１０から立設された筒状部２を有すると共にその外周面に凹凸形状を有する歯形面２０を設けてなり，さらにベース部１０の上下に円筒状の軸部１７，１８を一体的に配設した歯形鍛造品である。そして，歯形面の凸２１部の裏側面２５には，上記凸部２１の突出方向に向けて窪んだ窪部３を設けてある。
【００３３】
本例の歯形鍛造品１を製造するにあたっても，実施形態例１と同様に，上記窪部３を熱間鍛造工程において形成し，その後の冷間鍛造工程において窪部３を拘束しない状態で筒状部２に冷間鍛造を加える。これにより，実施形態例１と同様に非常に優れた作用効果を得ることができる。
【００３４】
実施形態例５
本例は，実施形態例１と同様の製造方法を，カウンタードリブンギア用鍛造品以外の歯形鍛造品に適用した例である。
本例の歯形鍛造品１は，図８に示すごとく，中央に貫通穴５１を有する円盤状のベース部１０から立設された筒状部２を有すると共にその内周面に凹凸形状を有する歯形面２０を設けてなる歯形鍛造品である。そして，歯形面の凸２１部の裏側面（外側面）２５には，上記凸部２１の突出方向に向けて窪んだ窪部３を設けてある。即ち，本例の歯形鍛造品１は，実施形態例１〜４と異なり，歯形面２を筒状部２の内面に設け，窪部３を外面に設けた。
【００３５】
本例の歯形鍛造品１を製造するにあたっても，実施形態例１と同様に，上記窪部３を熱間鍛造工程において形成し，その後の冷間鍛造工程において窪部３を拘束しない状態で筒状部２に冷間鍛造を加える。このとき，金型形状は，実施形態例１における金型７の内外の状態を逆にしたような形状のものを用いる。これにより，実施形態例１と同様に非常に優れた作用効果を得ることができる。
【００３６】
【発明の効果】
上述のごとく，本発明によれば，筒状部への歯形面の形成を，鍛造により精度よく行うことができる，筒状部に歯形面を有する歯形鍛造品の製造方法を提供することができる。
【図面の簡単な説明】
【図１】実施形態例１における，（ａ）熱間鍛造後，（ｂ）冷間鍛造後の，歯形鍛造品を示す斜視図。
【図２】実施形態例１における，冷間鍛造時の金型と筒状部との関係を示す説明図。
【図３】実施形態例１における，カウンタードリブンギアを示す斜視図。
【図４】実施形態例１における，（ａ）本例のカウンタードリブンギア，（ｂ）従来例のカウンタードリブンギア，の断面図。
【図５】実施形態例２における，歯形鍛造品を示す斜視図。
【図６】実施形態例３における，歯形鍛造品を示す斜視図。
【図７】実施形態例４における，歯形鍛造品を示す斜視図。
【図８】実施形態例５における，歯形鍛造品を示す一部切り欠き断面斜視図。
【図９】従来例における，カウンタードリブンギアの製造工程を示す説明図。
【図１０】従来例における，カウンタードリブンギアの斜視図。
【符号の説明】
１．．．歯形鍛造品（カウンタードリブンギア用鍛造品），
１０．．．ベース部，
１１．．．軸穴部，
１２．．．リング状溝，
２．．．筒状部，
２０．．．歯形面，
２１．．．凸部，
２２．．．凹部，
２５．．．裏側面，
３．．．窪部，[0001]
【Technical field】
The present invention relates to a method for integrally manufacturing a tooth-shaped forging having a tooth-shaped surface in a cylindrical portion.
[0002]
[Prior art]
For example, as shown in FIG. 10, a counter driven gear 9 in which a parking gear member 91 and a driven gear member 92 are coaxially arranged is used as an automobile part.
Conventionally, in manufacturing this part, first, as shown in FIGS. 9A and 9B, a parking gear member 91 and a driven gear member 92 are separately manufactured by hot forging.
[0003]
Next, as shown in FIGS. 9C and 9D, a tooth profile surface 915 having an uneven shape is formed on the outer peripheral surface of the parking gear member 91 by machining. Also, the inner peripheral surface of the shaft hole 924 of the driven gear member 92 is machined.
Next, as shown in FIG. 9E, the driven gear member 92 and the parking gear member 91 are press-fitted and welded to be integrated.
Thereafter, as shown in FIG. 10, finishing machining is performed to obtain the counter driven gear 9 having the parking gear member 91 and the driven gear member 92 integrally.
[0004]
As described above, in the case of the counter driven gear 9, a manufacturing method is adopted in which the tooth shape is formed in advance on the cylindrical parking gear member 91 by machining, and then the gear is joined to the driven gear member 92 to be integrated. .
Such a manufacturing method is not limited to the counter driven gear, but is applied to the case of manufacturing a part having a cylindrical part erected on a base part and having a tooth shape on an inner peripheral surface or an outer peripheral surface thereof.
[0005]
[Problem to be solved]
However, the conventional manufacturing method has the following problems.
That is, in the manufacturing method, it is necessary to form the tooth surface on the cylindrical portion by machining, and the process is complicated. Therefore, the cost increases. Further, since the joining between the cylindrical portion and the base portion is performed by press-fitting, welding, or the like, it is necessary to strengthen the joining portion. Therefore, it is difficult to reduce the weight.
[0006]
As a countermeasure, a method of integrally manufacturing the base portion and the cylindrical portion by forging can be considered. In this case, since it is difficult to finish the shape of the tooth profile with high accuracy only by hot forging, it is necessary to perform cold forging after hot forging. However, conventionally, even if cold forging is performed, it is difficult to accurately finish the shape of the tooth profile surface, and defects such as underfill and buckling occur. In addition, when a high working ratio is applied to improve the shape accuracy at the time of cold forging, the die for cold forging may not be able to withstand the load and may be damaged. Therefore, conventionally, it has not been possible to accurately form a tooth profile on the cylindrical portion by forging.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is capable of forming a tooth profile on a cylindrical portion with high accuracy by forging. It seeks to provide a way.
[0008]
[Means for solving the problem]
The invention according to claim 1 is a method for manufacturing a tooth profile forging having a cylindrical portion erected from a base portion and having a tooth profile surface having an uneven shape on an outer peripheral surface or an inner peripheral surface thereof,
The base portion and the cylindrical portion are formed by hot forging the material, and the outer peripheral surface or the inner peripheral surface of the cylindrical portion is provided with a toothed surface having irregularities, and the convexity of the toothed surface is provided. On the back side of the part, a concave part is provided that is depressed in the projecting direction of the convex part.
Thereafter, cold forging is applied to the cylindrical portion without restraining the concave portion. The method for manufacturing a tooth-shaped forged product having a tooth-shaped surface in the cylindrical portion is provided.
[0009]
The most remarkable point in the present invention is that, at the time of the hot forging, a cylindrical portion having the concave portion is provided, and then the cylindrical portion is subjected to cold forging without restraining the concave portion. is there.
As the shape of the convex portion of the tooth profile, various known shapes such as a rectangular shape, a trapezoidal shape, a triangular shape, and the like can be applied. Various shapes can be applied to the shape of the recess.
[0010]
Next, the operation of the present invention will be described.
In the present invention, first, the base material and the cylindrical portion are integrally provided by hot forging the material, and the tooth surface is provided on the cylindrical portion. At this time, as described above, on the rear side surface of the convex portion of the tooth profile surface, a concave portion that is concave toward the projecting direction of the convex portion is provided. Due to the formation of the depressions, extremely high-precision processing can be performed in the subsequent cold forging.
[0011]
That is, in the cold forging, the processing is performed in such a manner that the concave portion of the tooth profile surface formed by the hot forging is not restrained. More specifically, the cavity with respect to the back surface of the tooth profile of the mold used for cold forging is designed so as not to come into contact with the recess. Thus, even when an excessive load is applied during cold forging of the tooth profile surface, it is released in the recess. Therefore, a sufficiently high load can be applied to the tooth profile surface without worrying about breakage of the mold as in the related art. Therefore, the convex and concave portions of the tooth profile are formed into a desired shape along the cavity shape by a high load, and the excess load is released by the phenomenon of increasing the thickness of the concave portion.
[0012]
Therefore, if this manufacturing method is used, the cylindrical portion having the tooth surface and the base portion can be easily formed integrally, and the shape of the tooth surface can be formed with extremely high precision. For this reason, the conventional machining for forming the tooth profile is unnecessary, and the process can be streamlined and the cost can be reduced.
[0013]
Next, as in the second aspect of the present invention, it is preferable that the concave portion has an arc-shaped cross section. In this case, by forming the surface of the concave portion into an arc-shaped smooth shape, the formation by forging can be facilitated, and stress concentration and the like can be avoided.
[0014]
In the cold forging, the depth of the cavity relative to the cylindrical portion in the axial direction is D, and the height of the cylindrical portion before cold forging is H. , D <H, and (HD) /H≧0.1. By setting D <H, a load in the axial direction can be easily applied to the cylindrical portion. When the degree of processing is increased so that the above equation (HD) / H is 0.1 or more, the accuracy of the shape of the tooth profile can be particularly improved. The effect in the case where it is provided is effectively exhibited, and smooth molding can be performed without damaging the mold.
[0015]
When the height of the cylindrical portion in the axial direction is A and the thickness of the concave portion at the tip of the cylindrical portion is B, the relationship of B / A ≦ 0.3 is satisfied. This is particularly effective when is satisfied. That is, when B / A> 0.3, buckling and underfill phenomenon during cold forging hardly occur, but when B / A ≦ 0.3, these defects are likely to occur. There is a tendency. Also in this case, by providing the concave portion, the above-described problem at the time of cold forging can be easily avoided.
[0016]
According to a fifth aspect of the present invention, there is provided the tooth-shaped forged product, wherein the disk-shaped base portion, a shaft hole portion provided at a central portion of the base portion and having a shaft hole formed on an inner surface thereof, and And a parking gear portion as the cylindrical portion provided through a ring-shaped groove. The parking gear portion has a toothed surface having an uneven shape on the outer peripheral surface thereof. It can be a forged product for a counter driven gear. In this case, a lightweight, low-cost forged product for a counter driven gear can be manufactured.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
A method of manufacturing a tooth-shaped forged product having a tooth-shaped surface in a cylindrical portion according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a tooth-shaped forged product 1 manufactured in the present embodiment includes a disc-shaped base portion 10, a shaft hole portion 11 provided at a central portion of the base portion 10 and having a shaft hole 110 provided on an inner surface thereof, The shaft hole portion 11 and a parking gear portion as a cylindrical portion 2 provided via a ring-shaped groove 12 are integrally provided. A forged product for a counter driven gear in which the outer peripheral surface of the parking gear portion 2 is provided with a toothed surface 20 having an uneven shape. Further, as shown in FIG. 4 (a) to be described later, when the height in the axial direction is A and the thickness of the concave portion at the tip of the cylindrical portion 2 is B, as shown in FIG. There is a relationship of 0.3, and defects such as underfill are relatively likely to occur.
[0018]
In manufacturing this counter-driven gear forged product, first, as shown in FIG. 1A, a hot forging intermediate material 101 is produced by subjecting a material to hot forging a plurality of times. That is, the base portion 10 and the cylindrical portion (parking gear portion) 2 are formed by hot forging, and the tooth surface 20 having an uneven shape is provided on the outer peripheral surface of the cylindrical portion 2. At this time, on the back side surface 25 of the convex portion 21 of the tooth profile surface 20, a concave portion 3 concaved in the direction in which the convex portion 21 protrudes is provided.
[0019]
Next, as shown in FIG. 1B, cold forging is performed to obtain a forged product 1 for a counter driven gear.
In the cold forging step, the cylindrical portion is subjected to cold forging without restraining the concave portion. Specifically, as shown in FIG. 2, as a mold 7 for cold forging, an outer peripheral side surface 71 has a shape corresponding to the above-mentioned tooth profile surface 20, while an inner peripheral side surface 72 has a smooth shape. Those having an appropriate circumferential shape are used. In this example, when the axial depth of the cavity with respect to the cylindrical portion 2 is D (not shown), and the height of the cylindrical portion 2 before cold forging is H (FIG. 1A). , D <H, and the mold 7 was designed such that (HD) /H=0.1.
[0020]
By using such a mold 7, the toothed surface 20 of the cylindrical portion 2 is in close contact with the outer peripheral side surface 71 of the mold 7, while the back side surface 25 of the cylindrical portion 2 and the inner peripheral side surface 72 of the mold 71. Means that cold forging is performed in a state where a space 75 is provided between the hollow portion 3 and the hollow portion 3. As a result, as shown in FIG. 1B, the forged product 1 for the counter driven gear is obtained.
[0021]
Thereafter, as shown in FIG. 3, in the forged product 1 for a counter driven gear, the shaft hole 110 and the outer peripheral surface of the base portion 10 are subjected to machining to form a counter driven gear 100 of the product.
[0022]
Next, the operation and effect of this embodiment will be described.
In this example, as described above, the base portion 10 and the cylindrical portion 2 are integrally provided by hot forging, and the tooth surface 20 is provided on the cylindrical portion 2. At this time, as described above, the concave portion 3 that is concave toward the projecting direction of the convex portion 21 is provided on the rear side surface 25 of the convex portion 21 of the tooth profile surface 20. And in the said cold forging process, it processes in the state which does not restrict the recessed part 3 of the tooth profile surface 20 formed by the hot forging.
[0023]
Specifically, as shown in FIG. 2, cold forging is performed using the above-described mold 7. As a result, the tooth surface 20 of the cylindrical portion 2 is constrained by the outer peripheral side surface 71 of the mold 7 together with the convex portion 21 and the concave portion 22, while the concave portion 3 and the inner peripheral side surface 72 of the mold 7 Cold forging is performed while maintaining a gap between the two.
[0024]
Therefore, even when an excessive load is applied when the tooth profile surface 20 is cold forged, it is released in the concave portion 3. Therefore, it is possible to apply the above-mentioned processing to satisfy (HD) /H=0.1 without worrying about the damage of the mold, and to apply a sufficiently high load to the tooth profile surface 20. Can be.
Therefore, the convex portion 21 and the concave portion 22 of the tooth profile surface 20 are formed into a desired shape along the cavity shape without causing underfill or the like due to a high load, and the excess load increases the thickness of the concave portion. It is released by the phenomenon.
[0025]
Therefore, if this manufacturing method is used, the cylindrical part 2 having the tooth surface 20 and the base part 10 can be easily formed integrally, and the shape of the tooth surface 20 can be formed with extremely high precision. Can be. This eliminates the need for conventional machining for forming the tooth profile, thereby streamlining the process and reducing the cost of the counter-driven gear forging 1.
[0026]
Furthermore, the use of the counter-driven gear forged product 1 of the present example can significantly reduce the weight compared to the case where the conventional two parts are manufactured by joining. FIG. 4A shows a cross-sectional shape of a counter-driven gear 100 manufactured using the counter-driven gear forging 1 of the present example. On the other hand, FIG. 4B shows a cross-sectional shape of the counter driven gear 9 shown in the conventional example.
[0027]
As is apparent from the comparison between the two figures, the counter driven gear 100 of the present embodiment does not need to consider the reinforcement of the joint, so that the ring-shaped groove 12 between the shaft hole 11 and the parking gear 2 is not required. The portion can be made larger than in the prior art, thereby achieving a significant reduction in weight.
[0028]
Embodiment 2
This example is an example in which the same manufacturing method as that of the first embodiment is applied to a tooth profile forged product other than the counter-driven gear forged product.
As shown in FIG. 5, the tooth profile forged product 1 of this embodiment has a cylindrical portion 2 erected from a disk-shaped base portion 10 having a through hole 51 at the center and a tooth profile surface having an uneven shape on its outer peripheral surface. 20 is a tooth profile forged product. On the back side surface 25 of the convex portion 21 of the tooth profile surface, a concave portion 3 that is concave toward the projecting direction of the convex portion 21 is provided.
[0029]
In manufacturing the tooth profile forged product 1 of the present example, similarly to the first embodiment, the above-mentioned concave portion 3 is formed in a hot forging process, and the cylindrical portion is formed in a state where the concave portion 3 is not restrained in a subsequent cold forging process. Cold forging is applied to the shape 2. As a result, as in the case of the first embodiment, very excellent operational effects can be obtained.
[0030]
Embodiment 3
This example is also an example in which the same manufacturing method as that of the first embodiment is applied to a tooth-shaped forged product other than the counter-driven gear forged product.
As shown in FIG. 6, the tooth profile forged product 1 of this example is a tooth profile forged product that differs from the case of the second embodiment in that the shape of the central portion 52 of the base portion 10 is changed. Also in this example, a concave portion 3 that is concave toward the projecting direction of the convex portion 21 is provided on the rear side surface 25 of the convex portion 21 of the tooth profile.
[0031]
Also in this case, similarly to the first embodiment, the concave portion 3 is formed in a hot forging process, and in the subsequent cold forging process, cold forging is performed on the cylindrical portion 2 without restraining the concave portion 3. Add. As a result, as in the case of the first embodiment, very excellent operational effects can be obtained.
[0032]
Embodiment 4
This example is also an example in which the same manufacturing method as that of the first embodiment is applied to a tooth-shaped forged product other than the counter-driven gear forged product.
As shown in FIG. 7, the tooth profile forged product 1 of this example has a cylindrical portion 2 erected from a disk-shaped base portion 10 having a through hole 51 at the center and a tooth profile surface having an uneven shape on its outer peripheral surface. 20 is a tooth-shaped forged product in which cylindrical shaft portions 17 and 18 are integrally disposed above and below the base portion 10. On the back side surface 25 of the convex portion 21 of the tooth profile surface, a concave portion 3 that is concave toward the projecting direction of the convex portion 21 is provided.
[0033]
In manufacturing the tooth profile forged product 1 of the present example, similarly to the first embodiment, the above-mentioned concave portion 3 is formed in a hot forging process, and the cylindrical portion is formed in a state where the concave portion 3 is not restrained in a subsequent cold forging process. Cold forging is applied to the shape 2. As a result, as in the case of the first embodiment, very excellent operational effects can be obtained.
[0034]
Embodiment 5
This example is an example in which the same manufacturing method as that of the first embodiment is applied to a tooth profile forged product other than the counter-driven gear forged product.
As shown in FIG. 8, the tooth profile forged product 1 of this example has a cylindrical portion 2 erected from a disk-shaped base portion 10 having a through hole 51 at the center and a concave / convex shape on its inner peripheral surface. This is a tooth-shaped forged product provided with a surface 20. On the back side surface (outer surface) 25 of the convex portion 21 of the tooth profile surface, a concave portion 3 that is concave toward the projecting direction of the convex portion 21 is provided. That is, unlike the first to fourth embodiments, the tooth-shaped forged product 1 of this example has the tooth-shaped surface 2 provided on the inner surface of the cylindrical portion 2 and the concave portion 3 provided on the outer surface.
[0035]
In manufacturing the tooth profile forged product 1 of the present example, similarly to the first embodiment, the above-mentioned concave portion 3 is formed in a hot forging process, and the cylindrical portion is formed in a state where the concave portion 3 is not restrained in a subsequent cold forging process. Cold forging is applied to the shape 2. At this time, the shape of the mold is such that the inside and outside states of the mold 7 in the first embodiment are reversed. As a result, as in the case of the first embodiment, very excellent operational effects can be obtained.
[0036]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method for manufacturing a tooth-shaped forged product having a tooth-shaped surface in a cylindrical portion, which can accurately form a tooth-shaped surface in a cylindrical portion by forging. .
[Brief description of the drawings]
FIG. 1 is a perspective view showing a tooth forged product after (a) hot forging and (b) cold forging according to the first embodiment.
FIG. 2 is an explanatory diagram showing a relationship between a mold and a cylindrical portion during cold forging in the first embodiment.
FIG. 3 is a perspective view showing a counter driven gear according to the first embodiment.
FIG. 4 is a cross-sectional view of (a) a counter driven gear of the present example and (b) a counter driven gear of a conventional example in the first embodiment.
FIG. 5 is a perspective view showing a tooth-shaped forged product in a second embodiment.
FIG. 6 is a perspective view showing a tooth-shaped forged product according to a third embodiment.
FIG. 7 is a perspective view showing a tooth-shaped forged product according to a fourth embodiment.
FIG. 8 is a partially cutaway perspective view showing a tooth-shaped forged product in a fifth embodiment.
FIG. 9 is an explanatory view showing a counter-driven gear manufacturing process in a conventional example.
FIG. 10 is a perspective view of a counter driven gear in a conventional example.
[Explanation of symbols]
1. . . Tooth profile forged products (forged products for counter driven gear),
10. . . Base,
11. . . Shaft hole,
12. . . Ring-shaped groove,
2. . . Tubular part,
20. . . Tooth profile,
21. . . Convex part,
22. . . Recess,
25. . . Back side,
3. . . Hollow,

Claims

A method for manufacturing a tooth-shaped forging having a cylindrical portion erected from a base portion and having a tooth profile surface having an uneven shape on an outer peripheral surface or an inner peripheral surface thereof,
The base portion and the cylindrical portion are formed by hot forging the material, and the outer peripheral surface or the inner peripheral surface of the cylindrical portion is provided with a toothed surface having irregularities, and the convexity of the toothed surface is provided. On the back side of the part, a concave part is provided that is depressed in the projecting direction of the convex part.
Thereafter, cold forging is performed on the cylindrical portion without restraining the concave portion. A method for manufacturing a tooth profile forged product having a tooth profile on the cylindrical portion.

2. The method according to claim 1, wherein the recess has an arc-shaped cross section.

3. The cold forging according to claim 1, wherein in the cold forging, D is an axial depth of the cavity with respect to the cylindrical portion, and H is a height of the cylindrical portion before cold forging. And (HD) /H≧0.1, the method for producing a tooth-shaped forged product having a tooth-shaped surface in a cylindrical portion.

In any one of claims 1 to 3, when the axial height of the cylindrical portion is A and the thickness of the concave portion at the tip of the cylindrical portion is B, B / A ≦ 0.3. A method for producing a tooth-shaped forged product having a tooth-shaped surface in a cylindrical portion, wherein a relationship is established.

5. The toothed forged product according to claim 1, wherein the tooth-shaped forged product has a disk-shaped base portion, a shaft hole portion provided at a central portion of the base portion and having a shaft hole formed on an inner surface thereof, and A parking gear portion as the cylindrical portion provided integrally with the hole portion and the cylindrical portion provided through the ring-shaped groove, and a tooth profile surface having an uneven shape is provided on an outer peripheral surface of the parking gear portion. A method for producing a tooth-shaped forged product having a tooth-shaped surface in a cylindrical portion, characterized by being a forged product for a counter driven gear.