JP3752866B2 - Joining metal member joining method - Google Patents

Description

【０１００】
この表１において、ろう材コーティング方法の欄における「Ｆｒｉｃｔｉｏｎ」とは、バルブシートの表面部に拡散接合層及びろう材層を形成する際、ろう材を擦りつけることによりコーティングを行う方法のことである。一方、「超音波」とは、上記基本形態１で説明したように、超音波メッキによりろう材のコーティングを行う方法のことである。また、シート形状の欄における「薄肉」とは、図２６に示すように、バルブシートが最終形状に近い形状をして肉厚が薄いことをいう。一方、「厚肉」とは、図２７に示すように、上記基本形態と同様の形状をして肉厚が厚いことをいう。
【０１０１】
尚、バルブシートは、表２に示す各元素（Ｃｕを除く）が分散された粉末原料を焼結してなる焼結材を使用した。この表２において、数値は重量％であり、ＴＣとは、総炭素量（遊離炭素（黒鉛）とセメンタイトの炭素との合計量）のことである。そして、この各バルブシートのＣｕ割合は、後述の如くＣｕ系材料を溶浸した後の値であって、溶浸前はＣｕは全く含有されていない。
【０１０２】
【表２】

【０１０３】
また、ろう材には、９５重量％のＺｎ成分、４．９５重量％のＡｌ成分及び０．０５重量％のＭｇ成分（Ｚｎ−Ａｌ共晶合金）からなるものを使用した。
【０１０４】
さらに、各バルブシートの内部にはＣｕ系材料を溶浸し、表面にはＣｕメッキを施した。
【０１０５】
上記基本例１〜５の各バルブシートを、上記基本形態１と同様にして、接合装置により上記試験片６１に接合した。この接合時における加圧力及び電流値は、表１に示す値に設定した。尚、電流値については、加圧力の変化等によりバルブシート及び試験片６１間の接触抵抗が変化してバルブシートの埋め込み深さが変わるので、略同一埋め込み深さとなるように設定している。
【０１０６】
また、比較のために、厚肉形状でかつθ１＝３０°（０．５２ｒａｄ）のバルブシート（表面にＣｕメッキしたもの）を、加圧力及び電流値をそれぞれ２９４２０Ｎ（３０００ｋｇｆ）及び７０ｋＡとして固相拡散接合（圧接接合）した（従来例）。
【０１０７】
次に、上記基本例１〜５及び従来例のバルブシートの接合強度を測定した。すなわち、図２８に示すように、試験片６１を、バルブシート６２の接合した側が下側となるように治具台６３の上面に置き、このとき、バルブシート６２がその治具台６３に接触しないように、治具台６３の略中央部に設けた貫通孔６３ａの上側に位置させる。そして、試験片６１の貫通孔６１ａの上側から円筒状の加圧治具６４を挿入してバルブシート６２を押し、バルブシート６２が試験片６１から抜けたときの抜き荷重を測定する。この抜き荷重が接合強度に相当する。
【０１０８】
上記抜き荷重測定試験の結果を図２９に示す。この結果、基本例１と基本例２とを比較することで、超音波メッキによりバルブシートの表面部に拡散接合層及びろう材層を形成する方が、ろう材を擦りつけることによりコーティングを行う方法よりも接合強度が向上することが判る。これは、試験後のバルブシートの表面には、基本例２においては後述の如く拡散接合層が残っていたのに対し、基本例１においてはろう材層や拡散接合層の痕跡が殆ど認められなかったことから、基本例１では拡散接合層が完全に形成されていないためと推定することができる。
【０１０９】
また、基本例２と基本例３とを比較することにより、厚肉形状のバルブシートの方が薄肉形状よりも抜き荷重が大きくなることが判る。これは、基本例２のものは、バルブシートの各角部等に変形が生じていることから、変形によって接合面部に作用する実際の加圧力が低下したためと推定することができる。
【０１１０】
そして、基本例３と基本例４とを比較することにより、第１接合面部のテーパ角θ１が大きい基本例４の方が、上記基本形態１で説明したように、酸化皮膜破壊作用効果が優れていて、接合強度は大きくなることが判る。
【０１１１】
さらに、基本例４と基本例５とを比較すると、加圧力が大きい基本例５の方が接合強度は高くなることが判る。しかも、加圧力を２９４２０Ｎ（３０００ｋｇｆ）とすることで、従来例のものよりも接合強度が格段に向上することが判る。
【０１１２】
上記加圧力の影響に関してさらに詳細に調べるために、ろう材コーティング方法、シート形状及び第１接合面部のテーパ角θ１を上記基本例４，５と同じにして加圧力を９８０７Ｎ（１０００ｋｇｆ）、１４７１０Ｎ（１５００ｋｇｆ）及び２９４２０Ｎ（３０００ｋｇｆ）にそれぞれ設定してバルブシートを試験片６１に接合し、上記最初に行った抜き荷重測定試験と同様に、その抜き荷重を測定した。
【０１１３】
また、加圧力が９８０７Ｎ（１０００ｋｇｆ）のものと２９４２０Ｎ（３０００ｋｇｆ）のものとで接合後の試験片６１の硬さを測定した。この硬さの測定は、バルブシートの第１接合面部と第２接合面部との角部（図３１において接合面部からの距離＝０の点）から試験片６１の外周側に向かってバルブシートが接合された側と反対側に４５°（約０．７９ｒａｄ）傾いた方向に沿って所定の距離ごとに行った。
【０１１４】
上記抜き荷重測定試験の結果を図３０に、また硬さ測定試験の結果を図３１にそれぞれ示す。このことで、加圧力が大きいほど接合強度は高く、高加圧力の方が試験片６１の接合面部近傍の硬さが高いことが判る。これは、高加圧力の方が接触抵抗が低くて発熱量が小さい分、試験片６１の軟化が抑制されているからであり、軟化が抑えられると、塑性流動が確実に行われて酸化皮膜の破壊作用効果が高まると共に、ろう材の排出も確実に行われるためである。
【０１１５】
次いで、パルス通電の効果を調べるために、パルス通電を行うことによりバルブシートを試験片６１に接合した。このパルス通電の大電流値及び小電流値はそれぞれ７０ｋＡ及び０とした。また、大電流値パルスの通電時間は０．５秒とし、小電流値パルスの通電時間は０．１秒とした。さらに、大電流値パルス数は６パルスとした。一方、比較のために、連続通電（６０ｋＡの電流値で２秒間通電）によりバルブシートを試験片６１に接合した。尚、加圧力はどちらも２９４２０Ｎ（３０００ｋｇｆ）とした。
【０１１６】
そして、パルス通電及び連続通電により接合したものについて、各々、バルブシートの上下両端部（Ａ部）及び上下方向中央部（Ｂ部）における接合前及び接合後の硬さ、試験片６１においてバルブシートの第１接合面部と第２接合面部との角部から該試験片６１の外周側に向かってバルブシートが接合された側と反対側に４５°（約０．７９ｒａｄ）傾いた方向に沿った所定距離ごとの硬さ並びに抜き荷重を測定した。
【０１１７】
上記接合前及び接合後の硬さ測定試験の結果を図３２に示す。このことで、連続通電により接合したものは、特に上下方向中央部（Ｂ部）の硬さが接合後に非常に高くなるのに対し、パルス通電により接合したものは、徐冷により焼きが入らず、硬さが殆ど上昇していないことが判る。
【０１１８】
また、接合面部からの距離による硬さ測定試験の結果を図３３に示す。この結果、パルス通電により接合したものでは、バルブシートからの熱を受けることにより試験片６１の硬さが低くなっていることが判る。
【０１１９】
さらに、抜き荷重測定結果を図３４に示す。以上のことから、パルス通電により、バルブシート内部の徐冷を行って硬さが上昇するのを抑えつつ、試験片６１への放熱によりバルブシート及び試験片６１の温度差を低減して収縮量の差を小さくすることができ、しかも、接合強度を向上させることができる。
【０１２０】
続いて、パルス通電においてバルブシートが試験片６１にどのように埋め込まれていくかを調べるために、加圧開始からの時間に応じてその埋め込み量ｙ（図３５参照）を測定した。このとき、パルス通電の大電流値は６８ｋＡとし、小電流値は０とした。また、大電流値パルスの通電時間（Ｈ）、小電流値パルスの通電時間（Ｃ）及び大電流値パルス数（Ｎ）は可変とし、基本条件では、それぞれ０．５秒、０．１秒及び６パルスとした。そして、この基本条件に対していずれか１つのみを変えて試験を行った（変更条件については図３６参照）。
【０１２１】
上記埋め込み量測定試験の結果を図３６に示す。このことより、最初の大電流値パルスの通電により殆ど埋め込みが完了し、後の通電では埋め込みは進行していないことが判る。また、この試験の設定条件の範囲では、埋め込み量は殆ど変わらない。但し、大電流値パルスの通電時間が１秒と長い場合は、他の場合よりも最初の大電流値パルスの通電のときから埋め込み量が僅かに大きく、パルス数が９パルスと多い場合は、途中から試験片６１が軟化して埋め込みが進行することが判る。したがって、最初の大電流値パルスの通電ではバルブシートの埋め込みが行える条件に、また２回目以降の大電流値パルスの通電ではバルブシート内部の徐冷及びシリンダヘッド本体への放熱が行える条件にそれぞれ設定すればよい。
【０１２２】
次いで、バルブシートを焼結鍛造材とし、これを２９４２０Ｎ（３０００ｋｇｆ）の加圧力でパルス通電により試験片６１に接合した。このとき、パルス通電の大電流値は６０ｋＡとし、小電流値は０とした。また、大電流値パルスの通電時間、小電流値パルスの通電時間及び大電流値パルス数を、それぞれ０．５秒、０．１秒及び４パルスとした。尚、比較のために、Ｃｕ系材料で溶浸した焼結材からなるバルブシートを同様に試験片６１に接合した。但し、パルス通電の大電流値は５３ｋＡとした。そして、バルブシートが焼結鍛造材のものと溶浸した焼結材のものとについて、試験片６１においてバルブシートの第１接合面部と第２接合面部との角部から該試験片６１の外周側に向かってバルブシートが接合された側と反対側に４５°（約０．７９ｒａｄ）傾いた方向に沿った所定距離ごとの硬さを測定した。
【０１２３】
この結果を図３７に示す。このことより、溶浸した焼結材の方が試験片６１内部の硬さが低いことが判る。これは、Ｃｕ系材料の溶浸によりバルブシート内部の発熱が抑制されて接合面部において発熱が有効に行われたために、試験片６１が軟化したからである。しかし、バルブシートが焼結鍛造材であっても接合は良好に行われている。これは、鍛造によりバルブシート内部の空孔が潰されて、溶浸したのと同様の効果を有するからである。
【０１２４】
次に、上記実施形態に対応する実施例について説明すると、表３に示すように、シート材料、シート形状、上側電極及び試験片を異ならせて７種類の接合金属部材を作製した（実施例１〜３及び比較例１〜４）。この表３において、シート材料Ａ，Ｂ，Ｃ，Ｄは、表４に示すような成分のものをそれぞれ使用した。このシート材料Ａは、Ｃｕが全体に略均一に分散されたＦｅ系粉末原料を焼結したものであり、シート材料Ｂ，Ｃ，Ｄは、上記基本例と同様に、焼結材にＣｕ系材料を溶浸したものである（表４のＣｕの割合は溶浸後の値）。
【０１２５】
【表３】

【０１２６】
上記シート形状は、実施例１〜３では、図３８のようにした。つまり、第１接合面部と第２接合面部との間に第３接合面部を有する形状とし、上記実施形態と同様に、バルブシートの接合面部を２つの角部を有するように３つの傾斜面で構成している。一方、比較例１〜４では、図３９のように、第１接合面部及び第２接合面部のみを有する形状としている（上記基本形態１〜４と同じように１つの角部のみを有している）。尚、これらのバルブシートの外周部には、上記基本形態１〜４及び実施形態と異なって、本来設けるべきではない鉛直方向に沿った鉛直面を設けているが、この鉛直面までバルブシートを後述の試験片７１に埋め込んではいないので、この鉛直面の影響は無視することができる。
【０１２７】
また、表３における上側電極の欄において「従来電極」とは、図４１（ａ）に示すように、上側電極７５の電極本体７６上部に冷却水の流入口７８と流出口７９とを設けていて、電極本体７６の下端部に取り付けた電極チップ７７内に設けた冷却通路が袋小路状となっているものをいい、「改善電極」とは、図４１（ｂ）に示すように、電極本体７６上部に冷却水の流入口７８を設けると共に、電極チップ７７の側周面に冷却水の流出口７９を設けたもの（上記実施形態と同様）をいう。
【０１２８】
そして、表３において試験片面取りの欄が有りの場合には、バルブシートを図４０に示す試験片７１に接合したことを示している。この試験片７１は、上記試験片６１と同じ材料からなっていて、貫通孔７１ａの上部に面取り部７１ｂを有している。この面取り部７１ｂの鉛直方向に対する傾斜角は７０°（約１．２２ｒａｄ）であり、このことで、バルブシートの第２接合面部を試験片７１に予め面接触させた状態で通電及び加圧を行うようにしている。一方、試験片面取りの欄が無しの場合には、試験片７１の上部に面取り部７１ｂがない状態でバルブシートを接合したことを示している。
【０１２９】
上記各バルブシートは、２９４２０Ｎ（３０００ｋｇｆ）の加圧力でパルス通電により接合した。このとき、パルス通電の大電流値は５５ｋＡ（但し、試験片面取り無しのときは６０ｋＡ）とし、小電流値は０とした。また、大電流値パルスの通電時間、小電流値パルスの通電時間及び大電流値パルス数を、それぞれ０．５秒、０．１秒及び３パルスとした。
【０１３０】
ここで、上記シート材料Ａ，Ｂ，Ｃ，Ｄについての熱伝導率及び密度を測定した。この結果を表４に示す。このことより、シート材料Ａのものはシート材料Ｂ，Ｃ，Ｄに比べて密度が小さいことが判る。つまり、空孔を有している。一方、熱伝導率は、空孔の断熱作用によりシート材料Ｂ，Ｃ，Ｄの溶浸材に比べると小さくなっていることが判る。
【０１３１】
【表４】

【０１３２】
続いて、上記実施例１〜３及び比較例１〜４のバルブシートの抜き荷重を測定した。この抜き荷重測定試験の結果を図４２に示す。この結果、実施例１と比較例１とを比較することにより、バルブシートの接合面部を３つの傾斜面で構成した方が接合強度が向上していることが判る。これは、比較例１では、図４４に示すように、試験片７１の材料の流動が上側ほど第１接合面部から大きく剥離しているのに対し、実施例１では、図４３に示すように、試験片７１の材料の流れが各接合面部から剥離していないことから、酸化皮膜破壊とろう材の排出が十分になされたためと推定することができる。尚、図４３及び図４４の各顕微鏡写真の倍率は共に約２０倍である。
【０１３３】
また、実施例１と実施例２とを比較することにより、改善電極にすることで接合強度が向上することが判る。これは、改善電極により上側電極２４が確実に冷却され、このため、バルブシート３の過熱が抑えられてその接合面部が変形せず、酸化皮膜破壊とろう材の排出がより一層良好に行われたからである。
【０１３４】
さらに、実施例３のように試験片７１の面取り部７１ｂをなくすと、接合強度は比較例２〜４の溶浸材と同等以上になることが判る。この場合、面接触ではなく線接触となるためバルブシートの接合面部が少し変形するものの、加圧後直ぐに面接触となると共に、塑性流動が大きくなされるので、酸化皮膜破壊及びろう材排出が略完全になされると推定することができる。尚、この実施例３の抜き荷重測定試験後における顕微鏡写真（倍率約１０倍）を図４５に示す。このことより、試験片７１が破壊されており、接合部での強度が高いことが判る。
【０１３５】
次に、図４６に示すように、第１及び第２接合面部間に円弧状の凸面を形成したバルブシートを作製し、このバルブシートを試験片７１に面取りが無い状態で接合した。このときのバルブシートの材料は上記シート材料Ａとし、上側電極は従来電極とした。この接合後の顕微鏡写真（倍率約１０倍）を図４７に示す。このことより、凸面が完全に変形していることが判る。また、試験片７１の接合部が白くなっているのは、熱影響を受けてシリコンが消失したためと考えられる。したがって、円弧状の凸面を設けても、酸化皮膜の破壊効果は不十分であって、接合強度の向上は困難であることが判る。
【０１３６】
最後に、上記基本例の厚肉形状と同じバルブシート（銅溶浸したもの）に鉄側溶融反応層及びろう材層を形成する際に溶融メッキで行う場合と超音波メッキで行う場合とで抜き荷重にどのような差が生じるかを調べた。このとき、溶融メッキ及び超音波メッキを施した各バルブシートを、それぞれ２９４２０Ｎ（３０００ｋｇｆ）の加圧力でパルス通電により上記試験片６１に接合した。このパルス通電の大電流値は７０ｋＡとし、小電流値は０とした。また、大電流値パルスの通電時間、小電流値パルスの通電時間及び大電流値パルス数を、それぞれ０．５秒、０．１秒及び３パルスとした。
【０１３７】
この抜き荷重測定結果を図４８に示す。尚、参考のために固相拡散接合した場合の抜き荷重も併せて示す。この結果、超音波メッキの場合の方が溶融メッキの場合よりも接合強度が向上することが判る。但し、溶融メッキの場合でも固相拡散接合の場合よりも接合強度は向上している。
【０１３８】
そして、表５に、溶融メッキを施した直後におけるバルブシートの鉄側溶融反応層及びろう材層の化学成分と、超音波メッキを施した直後におけるバルブシートのろう材層の化学成分とを測定した結果を示す（数値は重量％）。尚、超音波メッキの場合は上述の如く鉄側溶融反応層が極めて薄いため、化学成分の測定は不可能であった。但し、線分析の結果では、鉄側溶融反応層が存在することが認められる。
【０１３９】
【表５】

【０１４０】
このことより、溶融メッキの場合には、超音波メッキの場合よりも鉄側溶融反応層がかなり厚くなると共に、鉄側溶融反応層におけるＺｎ成分の割合が少なくなって（Ｆｅ成分及びＡｌ成分の割合は多くなる）、ろう材の組成が共晶組成から大きく外れることも判る。したがって、溶融メッキの場合、ろう材層は共晶組成を維持しているものの、鉄側溶融反応層に非共晶組成のろう材が多く存在するため、ろう材を溶融させるための入熱量が多くなって試験片６１が軟化し、このことで酸化被膜の破壊効果やろう材の排出効果が不十分となって、上記測定結果のように接合強度が超音波メッキの場合よりも小さくなったと考えられる。このことより、ろう材として最初から共晶組成から大きく外れた組成のものを使用すると、ろう材層も共晶組成から大きく外れた組成となって、酸化被膜の破壊効果やろう材の排出効果が大幅に低下すると推定することができる。一方、超音波メッキの場合には、ろう材の組成を共晶組成ないしその近傍組成に維持して、酸化被膜の破壊効果やろう材の排出効果が確実に得られ、両金属部材の接合強度をより一層向上させることができる。
【０１４１】
【発明の効果】
以上説明したように、請求項１の発明では、第１の金属部材と第２の金属部材とを、該両金属部材間の加熱及び加圧により第１の金属部材を第２の金属部材側に押圧移動させることで第２の金属部材を塑性流動させながら接合する接合方法として、両金属部材の接合前に予め第１の金属部材の接合面部を、第１の金属部材の押圧方向に対して傾斜しかつ２つ以上の角部を有するように該傾斜方向に連続的に繋げられた３つ以上の傾斜面で構成しておく工程と、上記第１の金属部材における傾斜面で構成した接合面部に、該第１の金属部材及び第２の金属部材よりも融点が低くかつ第２の金属部材との共晶組成ないしその近傍組成からなるろう材と第１の金属部材との拡散層を介して上記ろう材層を形成する工程と、上記ろう材層を形成する工程後に、上記第１の金属部材と第２の金属部材とを、該両金属部材間の通電に伴う発熱による上記ろう材の融点以上の温度への加熱及び加圧により、ろう材における第２の金属部材成分の割合が多くなることでろう材が高融点化するようにろう材及び第２の金属部材の拡散層を形成しかつ溶融したろう材を両金属部材の接合面部間から排出しながら、上記両拡散層を介した液相拡散接合を行うことで、該両拡散層間の少なくとも一部に、該両拡散層同士の合金部を形成する工程とを含み、上記ろう材層を形成する工程を、ろう材浴中の第１の金属部材の表面部に超音波振動の付与によりろう材をコーティングすることで、上記ろう材と第１の金属部材との拡散層における厚さが１μｍ以下となるように第１の金属部材に上記ろう材層及び該拡散層を形成する工程としたことにより、複数の角部により第２の金属部材における材料の流れが各傾斜面から剥離するのを防止することができ、簡単な方法で両金属部材の接合強度を向上させることができる。また、第２の金属部材表面部における酸化被膜の破壊効果やろう材の排出効果が確実に得られ、接合強度のより高い接合金属部材が得られる。
【０１４２】
請求項２の発明によると、傾斜面を３つにしたことにより、低コストで第２の金属部材における材料の流れが各傾斜面から剥離するのを有効に防止することができる。
【０１４３】
請求項３の発明によると、第１の金属部材の押圧方向に対する傾斜角が最も小さい傾斜面の傾斜角を３０〜４０°に設定し、第１の金属部材の押圧方向に対する傾斜角が最も大きい傾斜面の傾斜角を６０〜７０°に設定したことにより、酸化被膜の破壊により接合強度を向上させるための最良の形態が得られる。
【０１４４】
請求項４の発明によると、第１の金属部材をＦｅ系材料とし、第２の金属部材をＡｌ系材料とし、ろう材をＺｎ系材料としたことにより、請求項１の発明における接合方法として、材料の組合せの最適化を図ることができる。
【０１４５】
請求項５の発明によると、ろう材をＺｎが９２〜９８重量％のＺｎ−Ａｌ系合金としたことにより、Ｆｅ系金属部材とＡｌ系金属部材とを接合する場合に、融点が低くて取り扱いの簡単なろう材の具体的材料が容易に得られる。
【０１４６】
請求項６の発明によると、第１の金属部材を、高電気伝導率元素であるＣｕが分散された粉末材料を焼結してなる焼結材としたことにより、第１の金属部材を所定の形状に簡単に製造することができる。また、接合を良好に行いつつ、溶浸工程を省略して製造コストを低減させることができると共に、接合後に高温下で使用する際に第１の金属部材の耐摩耗性を向上させることができる。さらに、低コストで第１の金属部材内部の抵抗値を有効に低減することができる。
【図面の簡単な説明】
【図１】 基本形態１に係る接合金属部材としてのエンジンのシリンダヘッドの要部を示す断面図である。
【図２】 バルブシート及びシリンダヘッド本体の接合状態を模式的に示す断面図である。
【図３】 バルブシートの接合前の形状を示す断面図である。
【図４】 バルブシートのシリンダヘッド本体への接合手順を示す説明図である。
【図５】 バルブシート及びシリンダヘッド本体の接合過程を模式的に示す説明図である。
【図６】 ろう材浴中のバルブシートの表面部に超音波振動の付与によりろう材をコーティングしている状態を示す説明図である。
【図７】 接合装置を示す側面図である。
【図８】 （ａ）は図７のVIII方向矢示図であり、（ｂ）は上側電極の下面図である。
【図９】 加圧及び通電の制御方法を示すタイミングチャートである。
【図１０】 加圧制御方法の他の例を示す図９相当図である。
【図１１】 Ａｌ−Ｚｎ合金の状態図である。
【図１２】 基本形態２を示す図９相当図である。
【図１３】 パルス通電によるバルブシート内部の温度変化を示すグラフである。
【図１４】 通電制御方法の他の例を示す図９相当図である。
【図１５】 バルブシート内周面部に冷却水を噴霧している状態を示す断面図である。
【図１６】 基本形態３を示す図９相当図である。
【図１７】 通電制御方法の他の例を示す図９相当図である。
【図１８】 バルブシートを縮径方向にも加圧してその熱膨張を抑えるようにしている状態を示す断面図である。
【図１９】 バルブシートの他の形状例を示す図３相当図である。
【図２０】 基本形態４に係る接合装置によりバルブシート及びシリンダヘッド本体を接合している状態を示す要部断面図である。
【図２１】 シリンダヘッド本体の接合前の形状を基本形態１〜４と異ならせた変形例を示す図４相当図である。
【図２２】 基本形態５に係る接合金属部材としてのエンジンのピストンを示す断面図である。
【図２３】 基本形態６に係る接合金属部材としてのエンジンのシリンダブロックの要部を示す断面図である。
【図２４】 本発明の実施形態においてバルブシートとシリンダヘッド本体とを接合している状態を示す要部断面図である。
【図２５】 基本例及び従来例の接合に用いた試験片を示す断面図である。
【図２６】 薄肉形状のバルブシートを示す断面図である。
【図２７】 厚肉形状のバルブシートを示す断面図である。
【図２８】 抜き荷重測定試験の要領を示す概略断面図である。
【図２９】 基本例１〜５及び従来例のバルブシートにおいて抜き荷重測定試験の結果を示すグラフである。
【図３０】 接合時加圧力と抜き荷重との関係を示すグラフである。
【図３１】 試験片の接合面部からの距離による硬さの変化を示すグラフである。
【図３２】 連続通電及びパルス通電においてバルブシートの接合前後の硬さの変化を示すグラフである。
【図３３】 連続通電及びパルス通電において試験片の接合面部からの距離による硬さの変化を示すグラフである。
【図３４】 連続通電及びパルス通電において抜き荷重測定試験の結果を示すグラフである。
【図３５】 埋め込み量測定試験における埋め込み量ｙを示す説明図である。
【図３６】 加圧開始からの時間と埋め込み量ｙとの関係を示すグラフである。
【図３７】 バルブシートが焼結鍛造材のものと溶浸した焼結材のものとにおいて試験片の接合面部からの距離による硬さの変化を示すグラフである。
【図３８】 実施例１〜３のシート形状を示す断面図である。
【図３９】 比較例１〜４のシート形状を示す断面図である。
【図４０】 実施例１，２及び比較例１〜４の接合に用いた試験片の要部断面図である。
【図４１】 （ａ）は従来電極を示し、（ｂ）は改善電極を示す。
【図４２】 実施例及び比較例のバルブシートにおいて抜き荷重測定試験の結果を示すグラフである。
【図４３】 実施例１におけるバルブシートと試験片との接合状態を示す顕微鏡写真である。
【図４４】 比較例１におけるバルブシートと試験片との接合状態を示す顕微鏡写真である。
【図４５】 実施例３の抜き荷重測定試験後の状態を示す顕微鏡写真である。
【図４６】 第１及び第２接合面部間に円弧状の凸面を有するバルブシートを示す断面図である。
【図４７】 図４６のバルブシートと試験片との接合状態を示す顕微鏡写真である。
【図４８】 バルブシートに鉄側溶融反応層及びろう材層を形成する際に溶融メッキで行う場合と超音波メッキで行う場合との抜き荷重測定の結果を示すグラフである。
【符号の説明】
１ シリンダヘッド（接合金属部材）
２ シリンダヘッド本体（第２の金属部材）
２ａ 接合面部
２ｂ ポート
３ バルブシート（第１の金属部材）
３ａ 第１接合面部（傾斜面）
３ｂ 第２接合面部（傾斜面）
３ｆ 第３接合面部（傾斜面）
５ 鉄側溶融反応層（ろう材とバルブシートとの拡散層）
６ アルミ側溶融反応層（ろう材とシリンダヘッド本体との拡散層）
７ ろう材層
１４ ろう材浴[0001]
BACKGROUND OF THE INVENTION
  The present invention belongs to a technical field related to a method of joining a joined metal member in which a first metal member and a second metal member are joined.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, various methods are known as a method for joining metal members, for example, in a case where a valve seat is joined to an opening peripheral portion of an intake and exhaust port of a cylinder head body in an engine cylinder head. .
[0003]
  As the method, for example, as disclosed in JP-A-8-1000070, the valve seat and the Al-based cylinder head main body are brazed and bonded with an Al-Zn-based brazing material and a fluoride-based flux. Has been proposed.
[0004]
  In addition, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-13481, a method is known in which metal members are joined to each other by resistance welding using contact resistance heating at the joint surface portion of both members. In this resistance welding, as shown in, for example, Japanese Patent Laid-Open No. 6-58116, heat is generated inside the sintered material by infiltrating metal into the holes of the valve seat made of the sintered material. Reducing the amount to increase the amount of heat generated at the joint surface, or forming a film on the surface of the valve seat as shown in, for example, JP-A-8-270499, and applying the film to the cylinder It has been proposed to melt when combined with the head body. Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-103070, the joint surface portion of the valve seat is preliminarily arranged in a horizontal plane perpendicular to the pressing direction (vertical direction) of the valve seat, and perpendicular to the horizontal plane (the valve seat It is composed of a vertical surface (along the pressing direction) and an inclined surface connecting the horizontal surface and the vertical surface, and the valve seat and the cylinder head body are in point contact with each other by energization and pressurization between both members. It has been proposed to join the cylinder head body while plastically deforming it by pressing and moving the valve seat toward the cylinder head body side.
[0005]
  Further, for example, as disclosed in Japanese Patent Laid-Open No. 8-200238, the valve seat and the cylinder head main body are fixed without forming a melt reaction layer while forming a plastic deformation layer on the joint surface portion of the cylinder head main body. It has been proposed to perform phase diffusion bonding (pressure welding). Further, in this publication, the joint surface portion of the valve seat is configured in advance by two inclined surfaces having different inclination angles with respect to the pressing direction of the valve seat, and a convex surface formed in an arc shape between the two inclined surfaces. It has been shown to keep.
[0006]
[Problems to be solved by the invention]
  By the way, when it is going to join the 1st metal member and the 2nd metal member by heating and pressurization between these metal members like the above-mentioned joining method by resistance welding and the solid phase diffusion joining method, As in the proposed examples (Japanese Patent Laid-Open Nos. 7-103070 and 8-200238), the second metal member is plastically flowed by pressing and moving the first metal member to the second metal member side. It is desirable to join them. That is, by doing in this way, the oxide film formed in the joint surface part of both metal members can be destroyed effectively, and the improvement of the joint strength of both metal members can be anticipated.
[0007]
  However, when the vertical surface along the pressing direction of the first metal member is formed in the joint surface portion of the first metal member as in the above-mentioned JP-A-7-103070, the second metal member In the portion corresponding to this vertical plane, the force for pressing the first metal member against the second metal member does not act, so the destruction action of the oxide film and the discharge action of the unreacted brazing material do not function effectively, The joint strength at this portion will be low.
[0008]
  Further, as described in Japanese Patent Laid-Open No. 8-200238, the joint surface portion of the first metal member is divided into two inclined surfaces having different inclination angles with respect to the pressing direction of the first metal member and an arc-shaped convex surface. Although the material of the second metal member can be made to flow along the two inclined surfaces from the convex surface, the second metal member is particularly inclined with respect to the pressing direction of the first metal member. In the portion corresponding to the inclined surface with the smaller angle, the material flow gradually peels off from the inclined surface as the material flows away from the convex surface. Is insufficient, and there is a problem that sufficient bonding strength cannot be obtained. This is the same even when a corner is formed by directly connecting two inclined surfaces instead of an arcuate convex surface.
[0009]
  The present invention has been made in view of such a point, and an object of the present invention is to join the first metal member and the second metal member while plastically flowing the second metal member as described above. In this case, by devising the shape of the joint surface portion of the first metal member, the material of the second metal member flows surely along the joint surface portion of the first metal member, so that both metal members The purpose is to improve the bonding strength.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, according to the present invention, the joining surface portion of the first metal member is previously inclined so as to be inclined with respect to the pressing direction of the first metal member and have two or more corner portions. It is composed of three or more inclined surfaces continuously connected in the inclined direction, and the joining surface portion has a melting point lower than that of the first metal member and the second metal member, and the second metal member. The brazing filler metal layer is formed through a diffusion layer of the brazing filler metal and the first metal member having the eutectic composition in the vicinity thereof or a composition in the vicinity thereof (on the surface portion of the first metal member in the brazing filler metal bath). By coating the brazing material by applying sonic vibration, the brazing material layer and the diffusion layer are applied to the first metal member so that the thickness of the diffusion layer between the brazing material and the first metal member is 1 μm or less. Forming) the first metal member and the second metal member, the both metal members OfDue to heat generated by energizationThe brazing material and the second metal member are heated so that the brazing material has a high melting point by increasing the proportion of the second metallic member component in the brazing material by heating and pressurizing to a temperature higher than the melting point of the brazing material. Liquid phase diffusion bonding is performed via both diffusion layers while forming a diffusion layer and discharging the molten brazing material from between the joint surfaces of both metal members.Thus, an alloy part between the two diffusion layers is formed at least in a part between the two diffusion layers.I did it.
[0011]
  Specifically, in the first aspect of the invention, the first metal member and the second metal member are moved to the second metal member side by heating and pressurizing between the two metal members. A joining method for joining the second metal member while causing the second metal member to plastically flow by being pressed and moved is an object.
[0012]
  Then, before joining the two metal members, the joining surface portion of the first metal member is inclined in advance with respect to the pressing direction of the first metal member and has two or more corners in the inclination direction. A step of forming three or more inclined surfaces connected together, and a bonding surface portion formed by the inclined surfaces of the first metal member, and having a melting point higher than that of the first metal member and the second metal member. Forming the brazing filler metal layer through a diffusion layer of the brazing filler metal having a low eutectic composition with the second metal member or a composition near the second metal member and the first metal member, and forming the brazing filler metal layer After the step of performing, the first metal member and the second metal member are placed between the metal members.Due to heat generated by energizationThe brazing material and the second metal member are heated so that the brazing material has a high melting point by increasing the proportion of the second metallic member component in the brazing material by heating and pressurizing to a temperature higher than the melting point of the brazing material. Liquid phase diffusion bonding is performed via both diffusion layers while forming a diffusion layer and discharging the molten brazing material from between the joint surfaces of both metal members.Thus, an alloy part between the two diffusion layers is formed at least in a part between the two diffusion layers.A step of forming the brazing filler metal layer by coating the brazing filler metal by applying ultrasonic vibration to the surface portion of the first metal member in the brazing filler metal bath. In this step, the brazing filler metal layer and the diffusion layer are formed on the first metal member so that the thickness of the diffusion layer with the metal member is 1 μm or less.
[0013]
  This makes it difficult for the material flow in the second metal member to peel off from the inclined surfaces due to the plurality of corners, and the oxide film is effectively destroyed at any portion between the first and second metal members. Thus, the first metal member and the second metal member are securely joined. As a result, the joining strength of both metal members can be improved by a simple method.
[0014]
  Moreover, since the brazing material is discharged and the first metal member and the second metal member are subjected to liquid phase diffusion bonding with both diffusion layers interposed therebetween, the oxide film, dirt, etc. on the surface of the second metal member are removed. While being discharged together with the brazing material, both diffusion layers are directly joined without interposing the brazing material layer. In general, the melting point of the brazing material is low and the heat resistance of the joint portion is low. In the present invention, however, the ratio of the brazing material component is increased by the alloying of the brazing material and the second metal member. Since it changes, the melting point of the bonding layer can be increased. For this reason, the intensity | strength and heat resistance more than the used brazing material can be provided. Thus, in the liquid phase diffusion bonding method having advantages not found in the past, it is necessary to reliably destroy the oxide film and discharge the brazing material. However, in the present invention, the plastic flow can be performed satisfactorily to break the oxide film, and the oxide film and the molten brazing material can be discharged. Therefore, the joining strength of both metal members can be improved reliably.
[0015]
  Moreover, by setting the thickness of the diffusion layer to 1 μm or less, it is possible to suppress the diffusion of the brazing material and the first metal member, and the proportion of the first metal member in the diffusion layer increases. It is possible to prevent the composition of the brazing material from greatly deviating from the eutectic composition. In addition, it is possible to prevent the amount of the brazing material deviating from the eutectic composition from increasing. For this reason, the composition of the brazing material can be maintained at the eutectic composition or in the vicinity thereof. As a result, the amount of heat input for melting the brazing material can be kept low, and the first or second metal member can be prevented from being softened and deformed. Therefore, the destruction effect of the oxide film and the discharge effect of the brazing material can be reliably obtained, and the joint strength between the two metal members can be further improved.
[0016]
  Furthermore, the brazing material layer is coated on the surface portion of the first metal member in the brazing material bath by applying ultrasonic vibration, thereby forming the brazing material layer and the diffusion layer on the first metal member. Since the oxide film or plating layer on the surface portion of the first metal member is destroyed by the cavitation action caused by, the method is more reliable than the method using mechanical friction in which the brazing material is rubbed against the surface portion of the first metal member. The brazing filler metal can be diffused to the first metal member side. Further, in the hot dipping method in which only the immersion is performed in the brazing material bath, it takes a long time to reliably form the brazing material layer and the diffusion layer on the first metal member, and the thickness of the diffusion layer is reduced to 1 μm or less. In contrast, in the present invention, the brazing material layer and the diffusion layer can be reliably formed in a short time, and a diffusion layer having a thickness of 1 μm or less can be easily and reliably realized. it can. Furthermore, the post-process for flux removal like the case of brazing using a flux is unnecessary. Therefore, a joining metal member with higher joining strength can be obtained by a simple method.
[0017]
  Furthermore, since heating to a temperature equal to or higher than the melting point of the brazing material is performed by heat generated by energization between the first and second metal members, it can be easily heated by resistance heat generation between the two metal members. The material can be melted easily and reliably. Therefore, a simple specific heating method can be easily obtained.
[0018]
  In the invention of claim 2, in the invention of claim 1, there are three inclined surfaces.
[0019]
  According to the present invention, the processing for forming the joint surface portion of the first metal member (processing of the mold when manufacturing by sintering or the like) is the easiest, and the processing cost can be reduced. On the other hand, it is possible to effectively prevent the flow of the material in the second metal member from being separated from each inclined surface only by forming two corners on the joint surface portion.
[0020]
  In the invention of claim 3, in the invention of claim 2, the inclination angle of the inclined surface having the smallest inclination angle with respect to the pressing direction of the first metal member is set to 30 to 40 °, and the pressing of the first metal member The inclination angle of the inclined surface having the largest inclination angle with respect to the direction is set to 60 to 70 °.
[0021]
  That is, when the inclination angle of the inclined surface having the smallest inclination angle is smaller than 30 ° (about 0.52 rad), the destruction effect of the oxide film is lowered, whereas when larger than 40 ° (about 0.70 rad), Since it becomes difficult to cause the second metal member to plastically flow and the first metal member becomes too large in a direction perpendicular to the pressing direction, it is 30 to 40 ° (about 0.52 to 0.70 rad). It is set. In addition, if the inclination angle of the inclined surface with the largest inclination angle is smaller than 60 ° (about 1.05 rad), it becomes difficult to set the inclination angle of the inclined surface with the smallest inclination angle in the above range, If the angle is larger than 70 ° (about 1.22 rad), it is difficult to cause the second metal member to plastically flow, so the angle is set to 60 to 70 ° (about 1.05 to 1.22 rad). Therefore, the best mode for improving the bonding strength by breaking the oxide film can be obtained.
[0022]
  In the invention of claim 4, in the invention of claim 1, the first metal member is made of Fe-based material, the second metal member is made of Al-based material, and the brazing material is made of Zn-based material. And
[0023]
  By doing so, the Zn-based brazing material easily forms the Fe-based first metal member and the Fe—Zn diffusion layer, and the Al-based second metal member and the Al—Zn diffusion layer, respectively. . Moreover, since it is joining via both diffusion layers, it can prevent effectively that the brittle intermetallic compound called Fe-Al is produced | generated. Therefore, the optimum combination of materials for the joining method in the invention of claim 1 can be obtained.
[0024]
  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the brazing material is made of a Zn-Al alloy having a Zn content of 92 to 98% by weight.
[0025]
  As a result, the brazing filler metal can be melted at 400 ° C. or lower, the Fe-based first metal member can be prevented from being deformed, and the Al-based second metal member can be melted or softened. Can be reliably prevented. Therefore, when joining an Fe-based metal member and an Al-based metal member, a specific material of a brazing material having a low melting point and easy handling can be easily obtained.
[0026]
  Claim6In the invention of claim 1,5In any one of the inventions, the first metal member is a sintered material obtained by sintering a powder material in which Cu, which is a high electrical conductivity element, is dispersed.
[0027]
  This makes it possible to easily manufacture the first metal member into a predetermined shape. Also, unlike the infiltrated material infiltrated with Cu or the like, vacancies are present as they are inside the first metal member, but since the high electrical conductivity elements are dispersed and sintered in advance. The resistance value inside the first metal member can be kept as low as that of the infiltrant. For this reason, even if the first metal member has pores inside, it is possible to suppress the internal heat generation at the time of energization and to achieve good bonding as with the infiltrant. On the other hand, since the thermal conductivity is smaller than the infiltrant due to the heat insulating action of the pores, in the case of a valve seat or the like in which the first metal member is used at a high temperature, the heat shrinkage is moderately suppressed during its use. An oxide film is formed. Therefore, while performing bonding well, the infiltration step can be omitted and the manufacturing cost can be reduced, and the wear resistance of the first metal member can be improved when used at a high temperature after bonding. . Here, the “high electrical conductivity element” means an electrical resistivity of 3 × 10.^-8An element of Ω · m or less. Furthermore, since the high electrical conductivity element is Cu, the resistance value inside the first metal member can be effectively reduced while keeping the cost low.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the basic form about the joining metal member used as the application object of this invention and the joining method of this member is demonstrated first, and after that, embodiment of this invention is demonstrated centering on a different point from the basic form.
[0029]
  (Basic form 1)
  FIG. 1 shows a main part of an engine cylinder head 1 as a joining metal member according to the basic form 1, and this cylinder head 1 has four intake and exhaust ports in a cylinder head body 2 as a second metal member. The substantially ring-shaped valve seats 3, 3,... (First metal member) are joined to the peripheral edges of the openings 2b, 2b,. The peripheral edge portions of the ports 2b are arranged in a substantially square shape when viewed from the lower side of the cylinder head 1, and the peripheral edge portions of the openings are joint surface portions 2a with the valve seats 3.
[0030]
  The inner peripheral surface portion of each of the valve seats 3 is a valve contact surface portion 3c, and is formed in a tapered shape whose diameter decreases upward along the shape of the valve upper surface. Further, the outer peripheral surface portion of each valve seat 3 is a first joint surface portion 3a with the cylinder head main body 2, and is surrounded by the joint surface portion 2a of the cylinder head main body 2 and formed in a tapered shape like the inner peripheral surface. ing. Furthermore, the upper surface portion of each valve seat 3 is a second joint surface portion 3b with the cylinder head body 2, and is inclined upward toward the inner peripheral side.
[0031]
  Each valve seat 3 is a sintered material made of an Fe-based material, and a Cu-based material as a high electrical conductivity material is infiltrated therein. As schematically shown in FIG. 2, Zn-Al eutectic alloy (about 95 wt% Zn component and the first and second joint surface portions 3 a and 3 b of each valve seat 3 with the cylinder head body 2 are formed. An iron-side molten reaction layer 5, which is a diffusion layer between the brazing filler metal and the valve seat 3, which is composed of about 5 wt% of an Al component (a eutectic composition with a material component of the cylinder head body 2 described later), is formed. . That is, the iron-side molten reaction layer 5 is made of Fe—Zn formed by diffusing the Zn component of the brazing material to the valve seat 3 side.
[0032]
  On the other hand, the cylinder head body 2 is made of an Al-based material, and an aluminum side melting reaction that is a diffusion layer between the brazing material and the cylinder head body 2 is formed on the joint surface portion 2a of the cylinder head body 2 with each valve seat 3. Layer 6 is formed. That is, the aluminum-side molten reaction layer 6 is made of Al—Zn formed by the liquid phase diffusion of the Zn component of the brazing material to the cylinder head body 2 in a molten state. The melting point of the brazing material is lower than that of each valve seat 3 and the cylinder head body 2.
[0033]
  The valve seats 3 and the cylinder head body 2 are liquid-phase diffusion bonded via the iron-side molten reaction layer 5 and the aluminum-side molten reaction layer 6. The thickness of the iron-side molten reaction layer 5 is Is set to 1 μm or less. The total thickness of the iron-side molten reaction layer 5 and the aluminum-side molten reaction layer 6 is preferably about 0.3 to 1.0 μm. In addition, an alloy part between the two molten reaction layers 5 and 6 is formed in at least a part (actually almost all parts) between the iron side molten reaction layer 5 and the aluminum side molten reaction layer 6. . The composition of the alloy part is Al: 5 to 10%, Zn: about 10%, Fe: the balance, and the composition of both the molten reaction layers 5 and 6 and the alloy part is gently inclined over the whole. ing.
[0034]
  A method of manufacturing the cylinder head 1 by joining the valve seats 3 to the peripheral edge portions (joint surface portions 2a) of the ports 2b of the cylinder head body 2 in the cylinder head 1 having the above-described configuration will be described. In the process, the top and bottom of the cylinder head body 2 and the valve seat 3 are reversed).
[0035]
  First, the valve seat 3 is produced by sintering powder of Fe-based material. At this time, as shown in FIG. 3, the valve seat 3 is formed on the inner peripheral side and the upper side (lower side in FIG. 1) so as to withstand the applied pressure when the valve seat 3 and the cylinder head body 2 are joined. It is formed to be thick. That is, at this stage, the valve contact surface portion 3c is not formed, but the inner peripheral surface is formed to extend straight upward and the upper surface is formed to be substantially horizontal. Further, the taper angle (θ1 in FIG. 3) of the first joint surface portion 3a with the cylinder head main body 2 is 30 ° (about 0.52 rad), and the inclination angle (θ2 in FIG. 3) of the second joint surface portion 3b is 20. Each is formed at ° (about 0.35 rad).
[0036]
  Then, a ring having substantially the same diameter as that of the valve seat 3 is prepared by sintering the powder of the Cu-based material, and then this ring is placed on the upper surface of the sintered valve seat 3 and placed in a heating furnace. By melting, a Cu-based material is infiltrated into the valve seat 3. Thereafter, a Cu plating layer (about 2 μm) is applied to the entire surface portion including the first and second joint surface portions 3a and 3b of the valve seat 3 from the viewpoint of preventing oxide film formation.
[0037]
  Subsequently, as schematically shown in FIG. 5A, a brazing filler metal layer 7 is formed on the first and second joint surface portions 3 a and 3 b of the valve seat 3 via the iron-side molten reaction layer 5. At this time, the thickness of the iron-side molten reaction layer 5 is set to 1 μm or less on the valve seat 3. In order to form the iron-side molten reaction layer 5 and the brazing material layer 7 on the valve seat 3 in this way, the brazing material is coated on the surface portion of the valve seat 3 in the brazing material bath by applying ultrasonic vibration (ultrasonic plating). ) That is, as shown in FIG. 6, one end of the diaphragm 11 is attached to the ultrasonic oscillator 12, and the valve seat 3 is placed on the upper surface of the other end of the diaphragm 11. Immerse in the brazing filler metal bath 14. In this state, when ultrasonic vibration is applied to the valve seat 3 from the ultrasonic oscillator 12 through the diaphragm 11, a Cu plating layer or a slight amount of Cu is formed on the surface portion of the valve seat 3 by cavitation action by ultrasonic waves. The oxide film is destroyed, the Zn component of the brazing material is diffused to the valve seat 3 side, and an iron-side molten reaction layer 5 made of Fe—Zn is formed, and the brazing material is formed on the surface side of the iron-side molten reaction layer 5. Layer 7 is formed. As a result, the iron-side molten reaction layer 5 can be formed more reliably and more easily than a method using mechanical friction in which the brazing material is rubbed against the surface portion of the valve seat 3 (friction soldering method). Here, as the ultrasonic plating conditions, for example, the brazing material bath temperature may be set to 400 ° C., the ultrasonic output to 400 W, and the ultrasonic vibration application time to 20 seconds. The iron-side molten reaction layer 5 and the brazing filler metal layer 7 can be formed by a hot dipping method in which the valve seat 3 is simply immersed in the brazing filler metal bath 14 by using a means for destroying an oxide film such as flux. The thickness of the iron-side molten reaction layer 5 can be reduced to 1 μm or less more easily and reliably by ultrasonic plating.
[0038]
  Next, the valve seat 3 is joined to the peripheral edge portion of the port 2b opening of the cylinder head body 2, that is, the joint surface portion 2a with the valve seat 3, which has been prepared by casting or the like in advance. At this time, the joining surface portion 2a of the cylinder head body 2 is different from the shape at the time of completion of joining (the same shape as the first and second joining surface portions 3a and 3b of the valve seat 3) as shown in FIG. 45 ° (about 0.79 rad).
[0039]
  And in order to join the valve seat 3 to the joining surface part 2a of the cylinder head body 2, as shown in FIG. 7, it is performed using a joining apparatus 20 obtained by improving a commercially available projection welding machine. The joining device 20 has a substantially U-shaped support body 21, and the upper and lower horizontal parts 21 a and 21 b of the support body 21 are cantilevered only by a vertical part 21 c on one side, and are vertically The side opposite to the portion 21c is open. A pressure cylinder 22 is provided below the upper horizontal portion 21 a of the support body 21, and the pressure cylinder 22 is attached to the cylinder rod 23 of the pressure cylinder 22 below and the same as the cylinder rod 23. A substantially cylindrical Cu upper electrode 24 that can move up and down on the axis is provided. On the other hand, on the upper side of the lower horizontal portion 21b, a Cu lower electrode 25 is provided in a state of facing the upper electrode 24 via a moving table 27, and a cylinder is formed on the inclined upper surface of the lower electrode 25. The head body 2 can be mounted such that the joint surface portion 2a is on the upper side of the cylinder head body 2. The horizontal position with respect to the lower horizontal portion 21b of the movable table 27 and the inclination of the upper surface of the lower electrode 25 can be adjusted, and the central axis of the joint surface portion 2a for joining the valve seat 3 becomes the vertical direction and the upper side. Adjustment is made so as to substantially coincide with the central axis of the electrode 24.
[0040]
  The upper and lower electrodes 24 and 25 are respectively connected to a welding power source 26 housed in the vertical portion 21c of the support body 21, and the valve seat 3 is attached to the joint surface portion 2a of the cylinder head body 2 on the upper surface of the lower electrode 25. When the upper electrode 24 is brought into contact with the upper surface portion of the valve seat 3 in the loaded state and the valve seat 3 and the cylinder head body 2 are pressurized by the pressurizing cylinder 22 and the welding power source 26 is turned on, the current is supplied to the valve seat 3. To the cylinder head body 2. Then, on the lower surface portion of the upper electrode 24 that contacts the upper surface portion of the valve seat 3, as shown in enlarged views in FIGS. 8 (a) and 8 (b), the side opposite to the vertical portion 21c of the support body 21 (support body). A cutout portion 28 as a non-energized portion is formed on the opening side of 21.
[0041]
  The cylinder head body 2 is placed on the upper surface of the lower electrode 25 of the joining device 20, and the horizontal position and lower position of the moving base 26 are arranged so that the central axis of the joining surface portion 2 a for joining the valve seat 3 substantially coincides with the upper electrode 24. After adjusting the inclination of the upper surface of the side electrode 24, the valve seat 3 is placed on the joint surface portion 2a. At this time, as shown in FIG. 4A, only the corners of the first and second joint surface portions 3a and 3b of the valve seat 3 are in contact with the joint surface portion 2a of the cylinder head body 2 (line contact is made). Is in the state).
[0042]
  Next, the upper electrode 24 is moved downward by the operation of the pressurizing cylinder 22 and brought into contact with the upper surface of the valve seat 3. From this state, pressurization of the valve seat 3 and the cylinder head body 2 is started. This applied pressure is desirably about 29420 N (3000 kgf). Then, as shown in FIG. 9, while maintaining this applied pressure, after about 1.5 seconds from the start of pressurization, the welding power source 26 is turned on, and the resistance heat generated by energization between the valve seat 3 and the cylinder head body 2 Thus, the brazing material layer 7 is heated to a temperature equal to or higher than the melting point of the brazing material to melt the brazing material. This current value is desirably about 70 kA.
[0043]
  At this time, since the brazing material is composed of a eutectic composition of about 95 wt% Zn component and about 5 wt% Al component, its melting point is very low as about 380 ° C. as shown in FIG. Soon it reaches the eutectic line and melts all at once. On the other hand, as shown in FIG. 4 (b), the valve portion 3 causes the corner portion between the first joint surface portion 3 a and the second joint surface portion 3 b to plastically flow the joint surface portion 2 a of the cylinder head body 2 as shown in FIG. The sheet 3 is embedded in the cylinder head body 2. As a result, the oxide film on the joint surface portion 2a of the cylinder head body 2 is broken, and the Zn component of the molten brazing material is liquid phase diffused to the cylinder head body 2 side, so that the aluminum side molten reaction layer 6 made of Al-Zn is formed. It forms (refer FIG.5 (b)). As a result of this diffusion, the brazing filler metal decreases in the proportion of the Zn component (increases the proportion of the Al component). As shown in FIG. 5C, the brazing material is pressed between the first and second joint surface portions 3a and 3b of the valve seat 3 and the joint surface portion 2a of the cylinder head body 2 together with the oxide film and dirt. Discharged. For this reason, the iron-side molten reaction layer 5 and the aluminum-side molten reaction layer 6 are directly joined without using the brazing material layer 7, and diffusion is further promoted between the two molten reaction layers 5 and 6. And it can prevent effectively that the brittle intermetallic compound called Fe-Al produces | generates through both the fusion | melting reaction layers 5 and 6. FIG. In addition, an alloy portion between the two molten reaction layers 5 and 6 is formed in almost all the portion between the iron side molten reaction layer 5 and the aluminum side molten reaction layer 6.
[0044]
  Therefore, the valve seat 3 and the cylinder head main body 2 are liquid-phase diffusion bonded through the iron-side molten reaction layer 5 and the aluminum-side molten reaction layer 6 in a short time, and the amount of heat input for melting the brazing material is minimized. Just do it. In addition, since the iron-side molten reaction layer 5 and the brazing material layer 7 are formed on the valve seat 3 by ultrasonic plating so that the thickness of the iron-side molten reaction layer 5 is 1 μm or less, the iron-side molten reaction layer 5 can prevent the composition of the brazing material from being greatly deviated from the eutectic composition or its neighboring composition, and the brazing material deviating from the eutectic composition or its neighboring composition as described above. Can be prevented. For this reason, the composition of the brazing material can be maintained as a eutectic composition or a composition in the vicinity thereof. As a result, since the joining can be performed with a small amount of heat input, deformation of the valve seat 3 and softening of the cylinder head body 2 can be suppressed, and the effect of destroying the oxide film and the effect of discharging the brazing material can be effectively enhanced. it can. Therefore, the coupling strength between the valve seat 3 and the cylinder head body 2 can be made extremely high. Further, since the brazing material diffuses to the cylinder head main body 2 side, the melting point of the brazing material is increased to about 500 ° C. or higher, so that it has heat resistance equal to or higher than the melting point of the brazing material used after joining. Become.
[0045]
  Furthermore, since the Cu-based material having a high electrical conductivity is infiltrated into the valve seat 3, the pores inside the sintered material are filled with the Cu-based material, and a part of the applied pressure is caused by the above-described pores. It is not used for crushing, and all of the applied pressure is directly used to plastically flow the joint surface portion 2a of the cylinder head body 2 and discharge the brazing material. Heat generation can be suppressed and the brazing material can be effectively melted.
[0046]
  Further, the upper and lower horizontal portions 21a and 21b of the support body 21 are cantilevered, and due to the bending of the upper and lower horizontal portions 21a and 21b, the pressurizing force is lowered on the opening side of the support body 21, and the joint surface portions 2a and 3a are correspondingly reduced. , 3b, the contact resistance of the portion corresponding to the opening side of the support body 21 is high, so the amount of heat generated on the opening side becomes excessive, the cylinder head body 2 melts locally, and a gap with the valve seat 3 is generated. Sometimes. In order to prevent this, as described above, the notch 28 may be formed on the opening side of the support body 21 in the lower surface of the upper electrode 24. In this case, the current value is small in the portion corresponding to the opening side of the support body 21 of the valve seat 3 and the cylinder head body 2. For this reason, the opening side of the support body 21 in the cylinder head body 2 does not melt locally and a gap is not formed between the valve head 3 and the valve head 3. Further, since the central axes of the cylinder rod 23 and the upper electrode 24 of the pressurizing cylinder 22 are coincident with each other, the difference in the applied pressure in the entire upper electrode 24 and the horizontality of the upper electrode 24 are compared with the apparatus in which they do not coincide. The change in the directional position can be reduced, the degree of notch of the notch 28 can be reduced, and the misalignment of the valve seat 3 with respect to the joint surface 2a of the cylinder head body 2 can be prevented. In addition, local melting of the cylinder head body 2 can be prevented by attaching an insulating member to the lower surface portion of the upper electrode 24 instead of providing the notch portion 28.
[0047]
  Subsequently, when the energization is stopped by turning off the welding power source 26 after 1.5 to 2.5 seconds from the start of energization, the valve seat 3 is completely embedded in the joint surface portion 2 a of the cylinder head body 2. (See FIG. 4 (c)). At this time, pressurization is continued without stopping. That is, the pressure is maintained until the aluminum-side molten reaction layer 6 is completely solidified and cooled, and the separation at the joint surfaces 2a, 3a, and 3b due to the difference in thermal expansion coefficient between the valve seat 3 and the cylinder head body 2 occurs. Prevent cracking.
[0048]
  In addition, as shown in FIG. 10, it is more desirable to reduce the applied pressure substantially simultaneously with the stop of energization. That is, since there is a high possibility that cracking will occur at each joint surface portion 2a, 3a, 3b by pressurization immediately after solidification when the deformability becomes small with a large applied pressure, the pressure is reduced to a level that can follow contraction deformation, It is possible to reliably prevent cracks at the joint surfaces 2a, 3a, 3b after solidification by pressurization.
[0049]
  Thereafter, the pressurization is stopped after about 1.5 seconds from the stop of energization, whereby the joining of the valve seat 3 and the cylinder head body 2 is completed. Subsequently, the same operation is repeated in the same cylinder head body 2 to join the valve seats 3 to the remaining three joining surface portions 2a, 2a,.
[0050]
  Finally, the valve contact surface portion 3c is formed by cutting the inner peripheral surface portion, the upper surface portion, and the like of each valve seat 3 and finished in a predetermined shape. As a result, the cylinder head 1 in which each valve seat 3 is joined to the peripheral edge of each port 2b opening of the cylinder head body 2 is completed.
[0051]
  Therefore, in the basic mode 1, the valve seat 3 and the cylinder head body 2 are joined by liquid phase diffusion bonding via the iron-side molten reaction layer 5 and the aluminum-side molten reaction layer 6 by heat generation and pressurization accompanying energization. Therefore, the cylinder head 1 having high bonding strength and heat resistance higher than that of the used brazing material can be obtained in a short time. Moreover, since it is only necessary to set the pressure and the current value so that the brazing material can be melted and discharged, the range of conditions under which high bonding strength can be obtained is wide. In addition, since the valve seat 3 can be made much smaller than the joining method by shrink fitting, the interval between the two ports 2b, 2b can be narrowed or the throat diameter can be increased. Further, the heat conductivity in the vicinity of the valve can be improved without generating a heat insulating layer, and the cooling water passage provided between the ports 2b and 2b can be brought closer to the valve seat side. The temperature in the vicinity can be effectively reduced. Furthermore, even if a glow plug or an injector is disposed between the ports 2b and 2b, a sufficient thickness can be ensured therebetween. Therefore, engine performance, reliability, and design freedom can be improved.
[0052]
  In the basic mode 1, each valve seat 3 is manufactured by sintering and Cu-based material is infiltrated therein. However, if the density inside each valve seat 3 is secured to some extent, it is not always necessary. There is no need to infiltrate. Moreover, since each valve seat 3 is made of a sintered forged material obtained by performing forging after sintering, voids inside the valve seat 3 can be eliminated in the same manner as infiltration. Material can be discharged effectively.
[0053]
  (Basic form 2)
  FIG. 12 shows the basic form 2, and the control method of energization at the time of joining the valve seat 3 and the cylinder head body 2 is different from the basic form 1.
[0054]
  That is, in this basic form, current is not continuously supplied at a constant current value, but pulse energization consisting of repetition of large and small current values is employed. The current value on the larger side of the pulse energization is constant at about 70 kA, and the current value on the smaller side is set to zero. The energization time of the large current value pulse is 0.25 to 1 second, and the energization time of the small current value pulse (the time during which no current is passed) is about 0.1 to 0.5 second. Furthermore, the number of large current value pulses is desirably 3 to 9 pulses (4 pulses in FIG. 12). The time from the start of pressurization to the start of energization of the first large current value pulse and the time from the stop of energization of the last large current value pulse to the stop of pressurization are 1.5 seconds as in the basic mode 1.
[0055]
  FIG. 13 shows a temperature change of the valve seat 3 when such pulse energization is performed. That is, since the heat capacity of the valve seat 3 made of an Fe-based material is considerably small, the temperature rise due to resistance heat generation of the valve seat 3 is severe, and in particular, the heat radiation to the upper electrode 24 and the cylinder head main body 2 is at the center in the vertical direction. It is difficult to dissipate heat compared to the upper and lower ends, and the contact resistance between the valve seat 3 and the cylinder head body 2 is high when the first large current pulse is energized. The temperature at the center is equal to or higher than the A1 transformation point when the energization of the first large current pulse is stopped. At this stage, since the valve seat 3 is almost completely embedded in the cylinder head body 2, it is possible to completely stop energization. However, the valve seat 3 starts from a temperature above the A1 transformation point. Since it is cooled rapidly, the vertical center part is burned and the hardness is increased.
[0056]
  Therefore, the second large current pulse is energized when the temperature drops slightly. At this time, unlike the first energization of the large current value pulse, the contact resistance is reduced by metallurgical bonding, the resistance heat generation is reduced, and heat dissipation is also performed. The valve seat 3 hardly rises in hardness because it is gradually cooled by repeating this process without increasing.
[0057]
  Therefore, in the basic mode 2, since the temperature of the central portion in the vertical direction of the valve seat 3 is gradually lowered by pulse energization, the hardness of the valve seat 3 does not increase greatly, and the inner peripheral surface portion is It is possible to prevent deterioration of workability when cutting. Further, it is possible to effectively suppress the valve from being easily worn due to the valve contact surface portion 3c becoming too hard.
[0058]
  In the basic mode 2, the large current value of pulse energization is constant and the small current value is 0. However, the present invention is not limited to this. For example, as shown in FIG. The small current value may be set to an intermediate value between the large current value and 0 without setting the small current value to 0 as shown in FIG. Further, as shown in FIG. 14 (c), after energizing a small current value pulse (0 in FIG. 14 (c)) following energization of the first large current value pulse, the current value is proportional to time. The energization may be switched to a continuous energization to decrease, and any energization control may be performed after the energization stop of the first large current value pulse as long as the valve seat 3 can be gradually cooled.
[0059]
  Further, in order to improve heat radiation to the upper electrode 24 of the valve seat 3, it is desirable to cool the water through the upper electrode 24. Further, as shown in FIG. 15, a cylindrical protrusion 31 is provided below the upper electrode 24 so as to face the inner peripheral surface portion of the valve seat 3, and the outer peripheral portion of the protrusion 31 is substantially equidistant in the circumferential direction. The cooling water in the upper electrode 24 may be sprayed on the inner peripheral surface portion of the valve seat 3 from a plurality of nozzles 32, 32,. As a result, the central part in the vertical direction of the valve seat 3 can be effectively cooled, and the valve seat 3 can be prevented from being overheated beyond the A1 transformation point.
[0060]
  (Basic form 3)
  FIG. 16 shows a basic form 3 in which a method for controlling energization at the time of joining the valve seat 3 and the cylinder head body 2 is different from the basic forms 1 and 2 described above.
[0061]
  That is, in this basic form, the joining device 20 has a limit switch (not shown) as seat position detecting means for detecting the position of the valve seat 3 in the height direction, and the valve seat 3 is attached to the cylinder head body 2. The limit switch is configured to be operated at a joint position where it is almost completely embedded. When the limit switch is operated after energization is started, the current is switched to a constant current value smaller than the initial current value (about 70 kA) at the time of energization. Then, the energization stop after switching is performed in time, and is stopped in 1.5 to 5 seconds from the start of energization of the initial current value.
[0062]
  The behavior in the case where the energization control is performed such that the valve seat 3 is switched to a small current value while the valve seat 3 is almost completely embedded in the cylinder head body 2 will be described.
[0063]
  First, at the start of energization, as described in the basic mode 2, the temperature of the valve seat 3 is significantly higher than that of the cylinder head body 2 made of an Al-based material, so that the coefficient of thermal expansion (linear expansion coefficient) is the cylinder head. Despite being smaller than the main body 2, the amount of thermal expansion is large. For this reason, when the energization is completely stopped in a state where the valve seat 3 is almost completely embedded in the cylinder head main body 2, the contraction amount of the valve seat 3 is larger than that of the cylinder head main body 2. Stress is generated.
[0064]
  Therefore, when energization is performed by switching to a current value smaller than the initial current value, the temperature of the valve seat 3 gradually decreases as in the basic mode 2. On the other hand, since the temperature of the cylinder head body 2 rises due to heat from the valve seat 3, the temperature difference between the valve seat 3 and the cylinder head body 2 becomes small. If energization is stopped in this state, the difference in shrinkage is reduced, and the thermal stress generated in the valve seat 3 can be reduced.
[0065]
  Therefore, in the basic mode 3, since the valve seat 3 is almost completely embedded in the cylinder head body 2 and switched to a current value smaller than the initial current value, the heat capacity of the valve seat 3 and the cylinder head body 2 is changed. And the difference of the thermal expansion amount (shrinkage amount) resulting from the difference of a thermal expansion coefficient can be made small. Therefore, it is possible to reduce the tensile thermal stress generated in the valve seat 3 and prevent vertical cracks from occurring on the inner peripheral surface portion.
[0066]
  In the basic mode 3, the current value after switching by the operation of the limit switch is constant. However, the present invention is not limited to this. For example, as shown in FIG. As shown in FIG. 17 (b), as shown in FIG. 17B, after the limit switch is operated, a large current value is applied as a pulse current smaller than the initial current value. Also good. Furthermore, even if it is the same energization control method as the said basic form 2, the same effect can be obtained.
[0067]
  Moreover, in the said basic form 3, although the position of the height direction of the valve seat 3 was detected with the limit switch and the electric current value was switched, position detection means, such as an optical sensor, may be used and a position is detected. Instead, the timing for switching the current value by time may be controlled. In this case, it is desirable to switch the current value within 0.25 to 1 second (more desirably 0.25 to 0.5 second) from the start of energization. During this time, the valve seat 3 is almost completely attached to the cylinder head body 2. It will be switched in the embedded state.
[0068]
  Furthermore, it is desirable to preheat the cylinder head body 2 to about 200 ° C. before joining the valve seat 3 to the cylinder head body 2. In this way, the temperature difference is further reduced, and the thermal stress can be kept low. As a result, the occurrence of vertical cracks in the valve seat 3 can be reliably prevented, and switching of the current value after the operation of the limit switch can be made unnecessary. In order to preheat the cylinder head body 2 in this way, the joining device 20 may be used. In other words, the upper and lower electrodes 24 and 25 of the joining device 20 are replaced with carbon ones, and the cylinder head body 2 is sandwiched between the electrodes 24 and 25 to perform preheating by turning on the welding power source. . At this time, since both the electrodes 24 and 25 are made of carbon, self-heating is large and the cylinder head body 2 can be preheated efficiently. In this way, inline compatibility is possible.
[0069]
  As shown in FIG. 18, an upper surface taper portion 3 d whose height increases toward the inner peripheral surface is provided at the upper portion of the valve seat 3, while the upper surface taper of the valve seat 3 is provided at the lower portion of the upper electrode 24. A conical concave portion 34 in which the portion 3 d is substantially fitted may be formed, and the upper surface tapered portion 3 d of the valve seat 3 may be pressurized in a state of being substantially fitted in the concave portion 34 of the upper electrode 24. That is, if pressure is applied in this way, pressure is also applied in the direction of diameter reduction of the valve seat 3, so that even if the temperature of the valve seat 3 rises, its expansion can be prevented. Even if the temperature difference is large, the difference in shrinkage is small. Therefore, even in this case, it is possible to prevent vertical cracks from occurring in the valve seat 3.
[0070]
  Further, as shown in FIG. 19, it is desirable to form chamfered portions 3e and 3e at corners of the inner peripheral surface portion, the upper surface portion, and the lower surface portion in order to alleviate stress concentration on the inner peripheral surface side of the valve seat 3. .
[0071]
  Moreover, since the inner peripheral surface side of the valve seat 3 is finally a scraped portion, only the scraped portion can be sintered as an inexpensive material.
[0072]
  (Basic form 4)
  FIG. 20 shows a main part of the bonding apparatus 20 according to the basic form 4 (note that the same parts as those in FIG. 7 are not described in detail, and only different points are described), and the energization path is the basic form 1 described above. It is different from ~ 3.
[0073]
  That is, in this basic form, the joining device 20 has the lower electrode 25 as in the basic forms 1 to 3, but the lower electrode 25 is not connected to the welding power source 26, and the valve seat 3 and It is used only to pressurize the cylinder head body 2. The upper electrode 24 is composed of two first and second electrodes 24a and 24b, and the first electrode 24a is the same as in the first to third embodiments. On the other hand, the second electrode 24b can be moved up and down independently by another pressure cylinder similar to the pressure cylinder 22 that moves the first electrode 24a up and down. The second electrode 24b is made of carbon, unlike the first electrode 24a, and both the electrodes 24a and 24b are connected to a welding power source 26, respectively.
[0074]
  The first and second electrodes 24 a and 24 b are in contact with the upper surfaces of the unjoined valve seat 3 to be newly joined and the previously joined valve seat 3 joined in the same cylinder head body 2, respectively. When the welding power source 26 is turned on, the current flows through the first electrode 24a, the non-joined valve seat 3, the cylinder head body 2, the pre-joined valve seat 3 and the second electrode 24b in order, and returns to the welding power source 26. ing. Thus, the already-joined valve seat 3 serves as a return-side energization path when the unjoined valve seat 3 is joined.
[0075]
  Therefore, in the basic mode 4, when the unjoined valve seat 3 is joined, the resistance heat generation amount is small on the side of the joined joint valve seat 3, and the internal temperature of the joined joint valve seat 3 rises like the unjoined valve seat 3. However, since the second electrode 24b made of carbon self-heats, even if the pre-bonded valve seat 3 is baked and the hardness is increased as described in the basic mode 2, Tempering can be performed. Moreover, tempering of the joined valve seat 3 can be performed without increasing the number of processes in-line. Therefore, it is possible to effectively suppress the thermal effect of an increase in the hardness of the valve seat 3 at the time of joining.
[0076]
  In the basic mode 4, the second electrode 24b is made of carbon. However, since this is a material having the largest self-heating value, the second electrode 24b is used when the temperature of the joined valve seat 3 becomes too high. 24b may be made of, for example, iron or brass, and can be effectively tempered.
[0077]
  Moreover, in the said basic forms 1-4, although the joint surface part 2a of the cylinder head main body 2 was made into the taper shape of 45 degrees (about 0.79 rad) before joining, you may make it eliminate this taper. In this case, as shown in FIG. 21A, the valve seat 3 is held in advance on the upper electrode 24. That is, a protrusion 33 whose outer diameter slightly decreases downward is formed at the lower part of the upper electrode 24, and the inner peripheral surface of the valve seat 3 is slightly tightly fitted to the outer peripheral surface of the protrusion 33. Fit with. Next, as in the basic forms 1 to 4, the upper electrode 24 is moved downward to join the valve seat 3 and the cylinder head body 2 by energization and pressurization (see FIG. 21B). At this time, the valve seat 3 is embedded in the cylinder head body 2 while the cylinder head body 2 is plastically flowed by the first joint surface portion 3 a and the second joint surface portion 3 b of the valve seat 3. When the joining is completed in this way, the valve seat 3 is completely embedded in the cylinder head body 2 as shown in FIG. 21C, and the joining surface portion 2a is formed in the cylinder head body 2. When the upper electrode 24 is raised, the protruding portion 33 is easily detached from the inner peripheral surface of the valve seat 3. Thus, even if the tapered joining surface portion 2a is not formed on the cylinder head body 2 in advance, the joining state between the cylinder head body 2 and the valve seat 3 is almost the same as the basic forms 1 to 4 described above. Further, by holding the valve seat 3 on the protrusion 33 of the upper electrode 24 in advance, it is possible to accurately position the valve seat 3 with respect to the cylinder head body 2 and to perform machining on the cylinder head body 2. Since it can be omitted, the productivity can be improved as compared with the case where the valve seat 3 is supplied and positioned and joined on the tapered joining surface portion 2a of the cylinder head body 2.
[0078]
  Further, in the above basic forms 1 to 4, the brazing material is a Zn-Al eutectic alloy (eutectic composition) with 95% by weight of Zn, but the eutectic composition or its vicinity composition (for example, Zn is 92 to 98% by weight). In this case, if the Zn ratio is 92 to 98% by weight, the melting point of the brazing material can be 400 ° C. or less, and the deformation of the valve seat 3 or the cylinder The melting or softening of the head body 2 can be reliably prevented, and the joint strength between the valve seat 3 and the cylinder head body 2 can be effectively improved.
[0079]
  (Basic form 5)
  FIG. 22 shows a piston 41 of a diesel engine as a bonded metal member according to the basic form 5, and this piston 41 is a piston main body 42 (second metal member) made of an Al-based material, similar to the basic form 1 described above. A wear-resistant ring 43 (first metal member) made of an Fe-based material is formed on the upper outer periphery of the piston body, and an Fe-based (for example, austenitic stainless steel or the like) is formed on the lip portion in the combustion chamber 42a provided at the upper center of the piston body 42 ) Reinforcing members 44 (first metal members) are joined to each other.
[0080]
  That is, conventionally, the piston main body 42 is cast by casting the wear-resistant ring 43. However, even if the piston main body 42 is subjected to T6 heat treatment to improve its strength, the wear-resistant ring 43 is cast in the state where the wear-resistant ring 43 is cast. Since a brittle intermetallic compound of -Al is generated, it is impossible to perform T6 heat treatment. However, in this basic form, the piston main body 42 is subjected to T6 heat treatment in advance, and the wear-resistant ring 43 can be joined to the piston main body 42. Further, even if the T6 heat treatment is performed after the wear-resistant ring 43 is joined to the piston main body 42, the heat resistance is good and Fe-Al is hardly generated, so there is no problem. For this reason, both the wear resistance and strength of the piston 41 can be improved.
[0081]
  On the other hand, the wall portion in the combustion chamber 42a of the piston main body 42 has a problem that cracks are particularly likely to occur at the corners. However, in this basic form, since the reinforcing member 44 is joined to the lip portion in the combustion chamber 42a, it is possible to prevent cracks from occurring in the wall portion in the combustion chamber 42a.
[0082]
  (Basic form 6)
  FIG. 23 shows the main part of the cylinder block 51 of the engine as a joining metal member according to the basic form 6, and this cylinder block 51 is similar to the basic form 1 in that the cylinder block main body 52 (the first block made of an Al-based material). The rib member 53 (first metal member) made of Fe-based material is joined to the upper portion of the water jacket 52a of the second metal member. Reference numeral 54 denotes a cast iron liner fitted into the inner peripheral surface of the cylinder.
[0083]
  That is, conventionally, in order to improve the rigidity of the cylinder block 51, a rib core is integrally formed on the upper portion of the water jacket portion using a sand core when the cylinder block main body 52 is cast. There is a problem that the cycle time during casting becomes long and the productivity is poor. However, in this basic form, the rib member 53 can be joined to the upper portion of the water jacket 52a of the cylinder block main body 52 in a short time while facilitating the casting of the cylinder block main body 52, thereby improving the rigidity of the cylinder block. Can do. For this reason, deformation of the liner 54 on the cylinder inner peripheral surface portion can be prevented, and engine performance such as LOC and NVH can be improved. Further, it can be applied to a linerless cylinder block.
[0084]
  (Embodiment)
  Here, an embodiment of the present invention will be described with reference to FIG. In this embodiment, a case where the cylinder head body 2 and the valve seat 3 are joined as in the basic forms 1 to 4 will be described. However, as in the basic forms 5 and 6, the piston main body 42 and the wear-resistant ring 43 are used. The present invention can be similarly applied to the case where the cylinder block body 52 and the rib member 53 are joined.
[0085]
  In this embodiment, first, the shape of the valve seat 3 is different from the basic form. That is, the third joint surface portion 3 f is formed between the first joint surface portion 3 a and the second joint surface portion 3 b of the valve seat 3, so that the joint surface portion of the valve seat 3 is in the pressing direction of the valve seat 3. And three inclined surfaces (first to third joint surface portions 3a, 3b, 3f) continuously connected in the inclination direction so as to have two or more corners. . The inclination angle (corresponding to θ1 in FIG. 3) of the first joint surface portion 3a having the smallest inclination angle (positioned on the uppermost side) with respect to the pressing direction (vertical direction) of the valve seat 3 is 30 °, which is the same as that of the basic form 1. (About 0.52 rad), corresponding to the inclination angle (90 ° −θ2 (see FIG. 3)) of the second joint surface portion 3b having the largest inclination angle with respect to the pressing direction of the valve seat 3 (located at the lowest side). ) Is set to the same 70 ° (about 1.22 rad) as in the basic mode 1, and the inclination angle of the third joint surface portion 3f is set to 45 °. The tilt angle (θ1) of the first joint surface portion 3a is 30 to 40 ° (about 0.52 to 0.70 rad), and the tilt angle (90 ° −θ2) of the second joint surface portion 3b is 60 to 70 °. (About 1.05 to 1.22 rad) may be set. That is, when the inclination angle of the first joint surface portion 3a is smaller than 30 ° (about 0.52 rad), the destruction effect of the oxide film is reduced. On the other hand, when the inclination angle is larger than 40 ° (about 0.70 rad), the cylinder head It becomes difficult to embed the valve seat 3 in the cylinder head body 2 by plastic flow of the joint surface portion 2a of the main body 2, and the outer diameter of the valve seat 3 becomes too large to narrow the interval between the two ports 2b and 2b. Therefore, the angle is set to 30 to 40 ° (about 0.52 to 0.70 rad). On the other hand, if the inclination angle of the second joint surface portion 3b is smaller than 60 ° (about 1.05 rad), it becomes difficult to set the inclination angle of the first joint surface portion 3a within the above range, but 70 ° (about about If it is larger than 1.22 rad), it is difficult to embed the valve seat 3 in the Linder head body 2, so the angle is set to 60 to 70 ° (about 1.05 to 1.22 rad). The first to third joint surface portions 3a, 3b, 3f of the valve seat are formed before the brazing material is coated on the surface portion of the valve seat 3 (which may be cut after sintering or sintered). Sometimes formed).
[0086]
  Secondly, the difference from the basic form is the material of the valve seat 3. That is, the valve seat 3 is a sintered material obtained by sintering an Fe-based powder raw material in which Cu as a high electrical conductivity element is dispersed substantially uniformly throughout, and has an internal structure as in the above basic form. The Cu-based material is joined to the pores without infiltration.
[0087]
  Thirdly, the difference from the basic form is the taper angle of the joint surface portion 2a before joining the valve seat 3 in the cylinder head body 2, and is not 45 ° (about 0.79 rad), but the second joint surface portion of the valve seat 3. It is set to 20 ° (about 0.35 rad) which is the same as the taper angle θ1 of 3b. That is, in the basic forms 1 to 4, the valve seat 3 and the cylinder head main body 2 are preliminarily brought into line contact with each other by energization and pressurization to be in surface contact from the middle of the joining. The second joining surface portion 3b and the joining surface portion 2a of the cylinder head body 2 are energized and pressurized while being in surface contact with each other. In addition, the surface contact here means a contact area of 40 to 200 mm.² (Desirably 40-100mm² ).
[0088]
  Fourth, the configuration of the upper electrode 24 is different. The upper electrode 24 includes an electrode body 35 and a substantially cylindrical electrode tip 36 attached to the tip of the electrode body 35 by screwing. Inside the electrode tip 36, a cooling passage 37 for flowing cooling water (cooling medium) for cooling the inside of the upper electrode 24 is formed so as to extend in the vertical direction. An upper end portion of the cooling passage 37 is connected to a lower end portion of a cooling passage (not shown) provided in the electrode body 35 so as to extend in the vertical direction. The upper end portion of the cooling passage of the electrode body 35 is connected to the cooling water. An inflow port is provided. On the other hand, at the lower end of the cooling passage 37 of the electrode tip 36, a cooling water outlet 37 a that opens to the side peripheral surface of the electrode tip 36 is provided. That is, an inlet of the cooling water is provided on the side opposite to the contact portion of the upper electrode 24 with the valve seat 3, and an outlet 37 a of the cooling water is provided on the side of the contact portion with the valve seat 3. Then, the cooling water is allowed to flow in one direction from the outlet 37a to energize while cooling the upper electrode 24 (particularly the electrode tip 36 that is at a high temperature). A discharge pipe 38 for discharging the cooling water is connected to the outlet 37a by screwing.
[0089]
  Therefore, in the above-described embodiment, the three inclined surfaces continuously connected in the inclined direction so that the joint surface portion of the valve seat 3 is inclined with respect to the pressing direction of the valve seat 3 and has two corners ( 1) to 3rd joining surface portions 3a, 3b, 3f), when the valve seat 3 is pressed and the cylinder head body 2 is plastically flowed, the material of the cylinder head body 2 is changed to each joining surface portion 3a. , 3b, 3f and flows along the joint surface portions 3a, 3b, 3f without peeling off. For this reason, in any part between the valve seat 3 and the cylinder head main body 2, the destruction of the oxide film and the discharge of the brazing material are reliably performed, and the bonding strength can be improved.
[0090]
  Further, the material of the valve seat 3 is a sintered material obtained by sintering an Fe-based powder raw material in which Cu as a high electrical conductivity element is dispersed, and the Cu-based material is not infiltrated into the vacancies therein. Since the bonding is performed, the resistance value of the valve seat 3 can be suppressed to be almost as low as that infiltrated with a Cu-based material by Cu dispersed in advance even if there are holes. For this reason, it is possible to suppress the internal heat generation at the time of energization and to perform the bonding satisfactorily as in the basic mode. On the other hand, since the thermal conductivity is smaller than that of the infiltrated due to the heat insulating action of the holes, the heat sink of the valve seat 3 is moderately suppressed during the operation of the engine, and an oxide film is formed. The wear resistance of can be improved.
[0091]
  And since the said valve seat 3 has low heat conductivity as mentioned above, when electricity supply and pressurization are carried out in the state which made the line contact previously like the said basic form, each joining surface part 2a, 3a, 3b in the initial stage of electricity supply will be carried out. , 3f becomes considerably large, and the valve seat 3 is easily overheated. Moreover, since the strength is relatively small due to the presence of the holes, the first to third joint surface portions 3a, 3b, 3f of the valve seat 3 are easily deformed. For this reason, there is a possibility that the plastic flow at the joint surface portion 2a of the cylinder head body 2 is not sufficiently performed and the effect of destroying the oxide film cannot be sufficiently obtained. However, in this embodiment, since the second joining surface portion 3b of the valve seat 3 and the joining surface portion 2a of the cylinder head body 2 are preliminarily brought into surface contact with each other, the energization and pressurization are performed. The amount of heat generated at 3a, 3b, and 3f can be set to an appropriate value to prevent overheating. Therefore, it is possible to prevent the valve seat 3 from being hardened even if it is rapidly cooled with the stop of energization, and to prevent deformation of the first to third joint surface portions 3a, 3b, 3f of the valve seat 3. Thus, bonding can be performed more satisfactorily.
[0092]
  Further, an inlet of the cooling water is provided on the opposite side of the upper electrode 24 to the contact portion with the valve seat 3, and an outlet 37 a of the cooling water is provided on the contact portion side with the valve seat 3. Since the upper electrode 24 is cooled by flowing cooling water in one direction from the outlet 37a to the outlet 37a, there is no need for a space for reciprocating the cooling water in the vertical direction as in the prior art, and the electrode tip 36 of the upper electrode 24 is used. Even if the diameter is small, a sufficient amount of cooling water can flow smoothly without stagnation. Therefore, the upper electrode 24 can be reliably cooled by a simple method, and softening of the upper electrode 24 can be suppressed and the life can be improved. Moreover, the overheating of the valve seat 3 can be suppressed, the deformation of the first to third joint surface portions 3a, 3b, 3f can be prevented, and the joint strength can be improved.
[0093]
  In the above embodiment, the joint surface portion of the valve seat 3 is configured by three inclined surfaces (first to third joint surface portions 3a, 3b, 3f), but four or more so as to have three or more corner portions. You may make it comprise in this inclined surface.
[0094]
  Moreover, in the said embodiment, although Cu was disperse | distributed to the powder raw material before sintering, high electrical conductivity elements are not restricted to Cu, Ag and electrical resistivity whose electrical conductivity is higher than Cu are 3x. 10^-8An element of Ω · m or less may be dispersed in the powder raw material and sintered. In this case, the thermal conductivity of the element is desirably 2 J / cm · s · K or more.
[0095]
  Further, in the above embodiment, the energization and pressurization are performed in a state where the second joint surface portion 3b of the valve seat 3 and the joint surface portion 2a of the cylinder head body 2 are in surface contact in advance. The first joint surface 3a or the third joint surface 3f and the joint surface 2a of the cylinder head body 2 may be brought into surface contact. Further, it may be arranged to make line contact as in the basic form described above, and as described as a note at the end of the basic form 4 so as to eliminate the taper before joining at the joining surface portion 2a of the cylinder head body 2. (In this case, it is a line contact).
[0096]
【Example】
  Next, specific examples will be described. However, a basic example corresponding to the basic mode will be described first, and then an example corresponding to the embodiment will be described.
[0097]
  First, as shown in FIG. 25, as a second metal member, a test piece 61 was cast with an Al alloy casting (AC4D defined in JIS standard H5202). And this test piece 61 was subjected to T6 heat treatment.
[0098]
  Subsequently, as shown in Table 1, five types of Fe-based valve seats were produced by changing the brazing material coating method, the sheet shape, and the taper angle θ1 of the first joint surface (basic examples 1 to 5).
[0099]
[Table 1]

[0100]
  In Table 1, “Friction” in the column of the brazing material coating method is a method of coating by rubbing the brazing material when forming the diffusion bonding layer and the brazing material layer on the surface portion of the valve seat. is there. On the other hand, “ultrasonic” is a method of coating a brazing material by ultrasonic plating as described in the basic mode 1 above. Further, “thin wall” in the column of the sheet shape means that the valve seat has a shape close to the final shape and is thin as shown in FIG. On the other hand, “thick” means that, as shown in FIG. 27, it has the same shape as the above basic form and is thick.
[0101]
  In addition, the valve seat used the sintered material formed by sintering the powder raw material in which each element shown in Table 2 (except Cu) was disperse | distributed. In Table 2, the numerical value is% by weight, and TC is the total amount of carbon (total amount of free carbon (graphite) and cementite carbon). The Cu ratio of each valve seat is a value after infiltrating a Cu-based material as described later, and Cu is not contained at all before infiltration.
[0102]
[Table 2]

[0103]
  The brazing material used was composed of 95 wt% Zn component, 4.95 wt% Al component and 0.05 wt% Mg component (Zn-Al eutectic alloy).
[0104]
  Further, a Cu-based material was infiltrated inside each valve seat, and the surface was plated with Cu.
[0105]
  Each valve seat of the basic examples 1 to 5 was joined to the test piece 61 by a joining device in the same manner as in the basic form 1. The applied pressure and current value during the joining were set to the values shown in Table 1. The current value is set to be substantially the same embedding depth because the contact resistance between the valve seat and the test piece 61 changes due to a change in the applied pressure and the like, and the embedding depth of the valve seat changes.
[0106]
  For comparison, a thick-walled valve seat with θ1 = 30 ° (0.52 rad) (Cu plated on the surface) is applied to a solid phase with a pressure and current values of 29420 N (3000 kgf) and 70 kA, respectively. Diffusion bonding (pressure welding) was performed (conventional example).
[0107]
  Next, the bonding strength of the valve seats of the basic examples 1 to 5 and the conventional example was measured. That is, as shown in FIG. 28, the test piece 61 is placed on the upper surface of the jig base 63 so that the joined side of the valve seat 62 is on the lower side. At this time, the valve seat 62 contacts the jig base 63. In order to prevent this, the jig base 63 is positioned above the through hole 63a provided at the substantially central portion. Then, a cylindrical pressure jig 64 is inserted from the upper side of the through hole 61 a of the test piece 61 and the valve seat 62 is pushed, and a pulling load when the valve seat 62 is pulled out from the test piece 61 is measured. This pull-out load corresponds to the bonding strength.
[0108]
  FIG. 29 shows the results of the above-described punch load measurement test. As a result, by comparing the basic example 1 and the basic example 2, the diffusion bonding layer and the brazing material layer are formed on the surface portion of the valve seat by ultrasonic plating, and the coating is performed by rubbing the brazing material. It can be seen that the bonding strength is improved as compared with the method. In the basic example 2, the diffusion bonding layer remained on the surface of the valve seat after the test as described later, whereas in the basic example 1, almost no trace of the brazing filler metal layer and the diffusion bonding layer was observed. Therefore, it can be estimated that the diffusion bonding layer is not completely formed in the basic example 1.
[0109]
  Moreover, by comparing the basic example 2 and the basic example 3, it can be seen that the valve load of the thick-walled valve seat is larger than that of the thin-walled valve. This can be presumed to be due to the fact that, in the basic example 2, each corner and the like of the valve seat is deformed, so that the actual applied pressure acting on the joint surface portion is reduced due to the deformation.
[0110]
  Then, by comparing the basic example 3 and the basic example 4, the basic example 4 having a larger taper angle θ1 of the first joint surface portion is superior in the effect of destroying the oxide film as described in the basic form 1. It can be seen that the bonding strength increases.
[0111]
  Furthermore, when the basic example 4 and the basic example 5 are compared, it can be seen that the bonding strength is higher in the basic example 5 having a larger applied pressure. In addition, it can be seen that by setting the applied pressure to 29420 N (3000 kgf), the bonding strength is significantly improved as compared with the conventional example.
[0112]
  In order to investigate the influence of the applied pressure in more detail, the applied pressure is set to 9807 N (1000 kgf), 14710 N (with the brazing material coating method, the sheet shape, and the taper angle θ1 of the first joint surface portion the same as in the basic examples 4 and 5 above. The valve seat was set to 1500 kgf) and 29420 N (3000 kgf), respectively, and the valve seat was joined to the test piece 61, and the punching load was measured in the same manner as the punching load measurement test performed first.
[0113]
  Moreover, the hardness of the test piece 61 after joining was measured with a pressure of 9807 N (1000 kgf) and 29420 N (3000 kgf). The measurement of the hardness is performed by measuring the valve seat from the corner portion (the distance from the joint surface portion = 0 in FIG. 31) between the first joint surface portion and the second joint surface portion of the valve seat toward the outer peripheral side of the test piece 61. The measurement was performed at predetermined distances along a direction inclined 45 ° (about 0.79 rad) to the side opposite to the bonded side.
[0114]
  FIG. 30 shows the results of the above-described punching load measurement test, and FIG. 31 shows the results of the hardness measurement test. Thus, it can be seen that the greater the applied pressure, the higher the bonding strength, and the higher applied pressure has a higher hardness in the vicinity of the bonded surface portion of the test piece 61. This is because the higher the applied pressure, the lower the contact resistance and the smaller the amount of heat generated, the softening of the test piece 61 is suppressed. When the softening is suppressed, the plastic flow is reliably performed and the oxide film This is because the destructive action effect is increased and the brazing material is also reliably discharged.
[0115]
  Subsequently, in order to investigate the effect of pulse energization, the valve seat was joined to the test piece 61 by performing pulse energization. The large current value and small current value of this pulse energization were 70 kA and 0, respectively. The energization time of the large current value pulse was 0.5 seconds, and the energization time of the small current value pulse was 0.1 seconds. Further, the number of large current value pulses was six. On the other hand, for comparison, the valve seat was joined to the test piece 61 by continuous energization (energization for 2 seconds at a current value of 60 kA). The applied pressure was 29420 N (3000 kgf) in both cases.
[0116]
  And about what was joined by pulse energization and continuous energization, respectively, the hardness before and after joining in the up-and-down both ends (A part) and the up-and-down direction center part (B part), valve seat in test piece 61 Along the direction inclined 45 ° (about 0.79 rad) from the corner of the first joint surface portion and the second joint surface portion toward the outer peripheral side of the test piece 61 on the side opposite to the side where the valve seat is joined. The hardness for each predetermined distance and the punching load were measured.
[0117]
  The result of the hardness measurement test before and after joining is shown in FIG. For this reason, the hardness at the center part (B part) in the vertical direction becomes very high after joining, especially for those joined by continuous energization, whereas those joined by pulse energization are not quenched by slow cooling. It can be seen that the hardness has hardly increased.
[0118]
  Moreover, the result of the hardness measurement test by the distance from a joint surface part is shown in FIG. As a result, it can be seen that in the case of joining by pulse energization, the hardness of the test piece 61 is lowered by receiving heat from the valve seat.
[0119]
  Furthermore, the results of measuring the punch load are shown in FIG. From the above, the amount of contraction is reduced by reducing the temperature difference between the valve seat and the test piece 61 by radiating heat to the test piece 61 while suppressing the increase in hardness by performing slow cooling inside the valve seat by pulse energization. Difference can be reduced, and the bonding strength can be improved.
[0120]
  Subsequently, in order to investigate how the valve seat is embedded in the test piece 61 in pulse energization, the amount of embedding y (see FIG. 35) was measured according to the time from the start of pressurization. At this time, the large current value of pulse energization was 68 kA, and the small current value was zero. Also, the energizing time (H) of the large current pulse, the energizing time (C) of the small current pulse, and the number of large current pulses (N) are variable. Under basic conditions, 0.5 sec and 0.1 sec, respectively. And 6 pulses. Then, the test was performed by changing only one of the basic conditions (see FIG. 36 for the changing conditions).
[0121]
  FIG. 36 shows the result of the embedding amount measurement test. From this, it can be seen that the embedding is almost completed by the energization of the first large current value pulse, and the embedding is not progressing by the energization later. Also, the amount of embedding remains almost unchanged within the range of the test setting conditions. However, when the energization time of the large current value pulse is as long as 1 second, the embedding amount is slightly larger than when the first large current value pulse is energized than in the other cases, and when the number of pulses is as large as 9 pulses, It can be seen that the test piece 61 softens from the middle and the embedding proceeds. Therefore, the condition that the valve seat can be embedded in the first energization of the first large current value pulse, and the condition that the cooling inside the valve seat and the heat radiation to the cylinder head body can be performed in the energization of the second and subsequent large current value pulses, respectively. You only have to set it.
[0122]
  Next, the valve seat was used as a sintered forged material, and this was joined to the test piece 61 by pulse energization with a pressure of 29420 N (3000 kgf). At this time, the large current value of pulse energization was 60 kA, and the small current value was zero. The energizing time of the large current value pulse, the energizing time of the small current value pulse, and the number of large current value pulses were 0.5 seconds, 0.1 seconds, and 4 pulses, respectively. For comparison, a valve seat made of a sintered material infiltrated with a Cu-based material was joined to the test piece 61 in the same manner. However, the large current value of pulse energization was 53 kA. And about the thing of the sintered forged material and the infiltrated sintered material of the valve seat, the outer periphery of the test piece 61 from the corners of the first joint surface portion and the second joint surface portion of the valve seat in the test piece 61 The hardness for each predetermined distance along the direction inclined 45 ° (about 0.79 rad) toward the side opposite to the side where the valve seat was joined was measured.
[0123]
  The result is shown in FIG. From this, it can be seen that the infiltrated sintered material has lower hardness inside the test piece 61. This is because the test piece 61 is softened because the heat generation inside the valve seat is suppressed by the infiltration of the Cu-based material and the heat generation is effectively performed at the joint surface portion. However, even if the valve seat is a sintered forged material, the bonding is performed well. This is because the holes inside the valve seat are crushed by forging and have the same effect as infiltration.
[0124]
  Next, examples corresponding to the above-described embodiment will be described. As shown in Table 3, seven types of bonded metal members were produced by changing the sheet material, the sheet shape, the upper electrode, and the test piece (Example 1). To 3 and Comparative Examples 1 to 4). In Table 3, the sheet materials A, B, C, and D have the components shown in Table 4, respectively. This sheet material A is obtained by sintering an Fe-based powder raw material in which Cu is dispersed substantially uniformly throughout, and the sheet materials B, C, and D are formed of a Cu-based sintered material as in the above basic example. The material was infiltrated (Cu ratio in Table 4 is the value after infiltration).
[0125]
[Table 3]

[0126]
  The sheet shape was as shown in FIG. 38 in Examples 1 to 3. That is, it has a shape having the third joint surface portion between the first joint surface portion and the second joint surface portion, and the joint surface portion of the valve seat is formed by three inclined surfaces so as to have two corner portions, as in the above embodiment. It is composed. On the other hand, in Comparative Examples 1-4, it is set as the shape which has only a 1st joint surface part and a 2nd joint surface part as FIG. 39 (it has only one corner | angular part like the said basic forms 1-4). ) Unlike the basic forms 1 to 4 and the embodiment described above, a vertical surface along the vertical direction that should not be originally provided is provided on the outer peripheral portion of these valve seats. Since it is not embedded in the test piece 71 described later, the influence of this vertical plane can be ignored.
[0127]
  In the column of the upper electrode in Table 3, “conventional electrode” means that an inlet 78 and an outlet 79 for cooling water are provided above the electrode body 76 of the upper electrode 75 as shown in FIG. The cooling passage provided in the electrode tip 77 attached to the lower end portion of the electrode body 76 is a bag path, and the “improvement electrode” is an electrode body as shown in FIG. The cooling water inlet 78 is provided at the upper portion 76, and the cooling water outlet 79 is provided on the side peripheral surface of the electrode tip 77 (similar to the above embodiment).
[0128]
  In Table 3, when the column for chamfering the test piece is present, it indicates that the valve seat is joined to the test piece 71 shown in FIG. The test piece 71 is made of the same material as the test piece 61, and has a chamfered portion 71b at the upper portion of the through hole 71a. The angle of inclination of the chamfered portion 71b with respect to the vertical direction is 70 ° (about 1.22 rad). With this, energization and pressurization are performed in a state where the second joint surface portion of the valve seat is in surface contact with the test piece 71 in advance. Like to do. On the other hand, when there is no column for the chamfer of the test piece, it indicates that the valve seat is joined without the chamfered portion 71b above the test piece 71.
[0129]
  The valve seats were joined by pulse energization with a pressure of 29420 N (3000 kgf). At this time, the large current value of pulse energization was 55 kA (however, 60 kA when there was no test piece chamfering), and the small current value was zero. The energizing time of the large current value pulse, the energizing time of the small current value pulse, and the number of large current value pulses were 0.5 seconds, 0.1 seconds, and 3 pulses, respectively.
[0130]
  Here, the thermal conductivity and density of the sheet materials A, B, C, and D were measured. The results are shown in Table 4. From this, it can be seen that the sheet material A has a lower density than the sheet materials B, C, and D. That is, it has holes. On the other hand, it can be seen that the thermal conductivity is smaller than the infiltrant of the sheet materials B, C, and D due to the heat insulating action of the holes.
[0131]
[Table 4]

[0132]
  Subsequently, the pulling load of the valve seats of Examples 1 to 3 and Comparative Examples 1 to 4 was measured. FIG. 42 shows the result of this punching load measurement test. As a result, by comparing Example 1 and Comparative Example 1, it can be seen that the joint strength is improved when the joint surface portion of the valve seat is composed of three inclined surfaces. In Comparative Example 1, as shown in FIG. 44, the flow of the material of the test piece 71 is largely separated from the first joint surface portion toward the upper side, whereas in Example 1, as shown in FIG. Since the material flow of the test piece 71 is not peeled from each joint surface portion, it can be estimated that the oxide film was destroyed and the brazing material was sufficiently discharged. Note that the magnifications of the micrographs in FIGS. 43 and 44 are both about 20 times.
[0133]
  Moreover, by comparing Example 1 and Example 2, it can be seen that the bonding strength is improved by using an improved electrode. This is because the upper electrode 24 is reliably cooled by the improvement electrode, so that the overheating of the valve seat 3 is suppressed, the joint surface portion is not deformed, and the oxide film breakage and the brazing material discharge are performed more satisfactorily. This is because the.
[0134]
  Furthermore, it can be seen that when the chamfered portion 71b of the test piece 71 is eliminated as in the third embodiment, the bonding strength is equal to or higher than that of the infiltrant of Comparative Examples 2 to 4. In this case, the contact surface portion of the valve seat is slightly deformed because it is a line contact instead of a surface contact, but the surface contact occurs immediately after pressurization and the plastic flow is increased. It can be estimated that it will be done completely. A micrograph (magnification of about 10 times) after the punching load measurement test of Example 3 is shown in FIG. From this, it can be seen that the test piece 71 is broken and the strength at the joint is high.
[0135]
  Next, as shown in FIG. 46, a valve seat in which an arcuate convex surface was formed between the first and second joining surface portions was produced, and this valve seat was joined to the test piece 71 without chamfering. At this time, the material of the valve seat was the seat material A, and the upper electrode was a conventional electrode. A micrograph (magnification approximately 10 times) after this joining is shown in FIG. From this, it can be seen that the convex surface is completely deformed. Moreover, it is considered that the bonding portion of the test piece 71 is white because silicon is lost due to thermal influence. Therefore, it can be seen that even if the arc-shaped convex surface is provided, the destruction effect of the oxide film is insufficient and it is difficult to improve the bonding strength.
[0136]
  Finally, when forming the iron side molten reaction layer and brazing material layer on the same valve seat (copper infiltrated) as in the basic example above, by hot dipping and by ultrasonic plating The difference in the punching load was investigated. At this time, each valve seat subjected to hot dipping and ultrasonic plating was joined to the test piece 61 by pulse energization with a pressure of 29420 N (3000 kgf). The large current value of this pulse energization was 70 kA, and the small current value was 0. The energizing time of the large current value pulse, the energizing time of the small current value pulse, and the number of large current value pulses were 0.5 seconds, 0.1 seconds, and 3 pulses, respectively.
[0137]
  FIG. 48 shows the result of measuring the punching load. For reference, the drawing load when solid phase diffusion bonding is performed is also shown. As a result, it is understood that the bonding strength is improved in the case of ultrasonic plating than in the case of hot dipping. However, the bonding strength is improved even in the case of hot dipping than in the case of solid phase diffusion bonding.
[0138]
  Table 5 shows the chemical components of the iron-side molten reaction layer and brazing material layer of the valve seat immediately after the hot-dip plating and the chemical component of the brazing material layer of the valve seat just after the ultrasonic plating. (Numerical value is% by weight). In the case of ultrasonic plating, since the iron-side molten reaction layer is extremely thin as described above, it is impossible to measure chemical components. However, the result of the line analysis shows that an iron-side molten reaction layer exists.
[0139]
[Table 5]

[0140]
  Thus, in the case of hot dip plating, the iron side molten reaction layer is considerably thicker than in the case of ultrasonic plating, and the proportion of Zn component in the iron side molten reaction layer is reduced (Fe component and Al component). It can also be seen that the composition of the brazing material deviates significantly from the eutectic composition. Therefore, in the case of hot dipping, although the brazing filler metal layer maintains the eutectic composition, there are many non-eutectic brazing filler metals in the iron-side molten reaction layer, so the amount of heat input for melting the brazing filler metal is low. The test piece 61 softened and this caused the oxide film destruction effect and brazing material discharge effect to be insufficient, and the joint strength was smaller than in the case of ultrasonic plating as in the above measurement results. Conceivable. Therefore, if a brazing material with a composition that deviates significantly from the eutectic composition from the beginning is used, the brazing material layer also deviates greatly from the eutectic composition, resulting in an oxide film destruction effect and brazing material discharge effect. Can be estimated to drop significantly. On the other hand, in the case of ultrasonic plating, the composition of the brazing material is maintained at the eutectic composition or in the vicinity thereof, so that the destruction effect of the oxide film and the discharging effect of the brazing material can be surely obtained. Can be further improved.
[0141]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the first metal member and the second metal member are placed on the second metal member side by heating and pressing between the two metal members. As a joining method in which the second metal member is joined while being plastically flowed by pressing and moving the first metal member in advance with respect to the pressing direction of the first metal member. And the step of forming three or more inclined surfaces continuously connected in the inclination direction so as to have two or more corners, and the inclined surface of the first metal member. A diffusion layer of a brazing material having a melting point lower than that of the first metal member and the second metal member and having a eutectic composition with the second metal member or a composition in the vicinity thereof and the first metal member are formed on the joint surface portion. A step of forming the brazing filler metal layer through the step, and a process for forming the brazing filler metal layer. Later, the said first metallic member and second metallic member, between the both metal membersDue to heat generated by energizationThe brazing material and the second metal member are heated so that the brazing material has a high melting point by increasing the proportion of the second metallic member component in the brazing material by heating and pressurizing to a temperature higher than the melting point of the brazing material. Liquid phase diffusion bonding is performed via both diffusion layers while forming a diffusion layer and discharging the molten brazing material from between the joint surfaces of both metal members.Thus, an alloy part between the two diffusion layers is formed at least in a part between the two diffusion layers.And forming the brazing filler metal layer by coating the brazing filler metal with the brazing filler metal by applying ultrasonic vibration to the surface portion of the first metal member in the brazing filler metal bath. By forming the brazing filler metal layer and the diffusion layer on the first metal member so that the thickness of the diffusion layer with the metal member is 1 μm or less, the plurality of corner portions in the second metal member It is possible to prevent the material flow from being separated from the inclined surfaces, and the joining strength between the two metal members can be improved by a simple method. Moreover, the destruction effect of the oxide film in the surface part of the second metal member and the discharge effect of the brazing material are surely obtained, and the joining metal member having higher joining strength is obtained.
[0142]
  According to the invention of claim 2, by providing three inclined surfaces, it is possible to effectively prevent the material flow in the second metal member from being separated from each inclined surface at low cost.
[0143]
  According to the invention of claim 3, the inclination angle of the inclined surface with the smallest inclination angle with respect to the pressing direction of the first metal member is set to 30 to 40 °, and the inclination angle with respect to the pressing direction of the first metal member is the largest. By setting the inclination angle of the inclined surface to 60 to 70 °, the best mode for improving the bonding strength by breaking the oxide film can be obtained.
[0144]
  According to the invention of claim 4, the first metal member is made of Fe-based material, the second metal member is made of Al-based material, and the brazing material is made of Zn-based material. It is possible to optimize the combination of materials.
[0145]
  According to the invention of claim 5, when the brazing material is a Zn-Al alloy having 92 to 98 wt% of Zn, when the Fe metal member and the Al metal member are joined, the melting point is low and the brazing material is handled. A specific material of a simple brazing material can be easily obtained.
[0146]
  Claim6According to the invention, the first metal member is formed into a predetermined shape by forming the first metal member into a predetermined shape by sintering a powder material in which Cu, which is a high electrical conductivity element, is dispersed. Easy to manufacture. Moreover, while performing joining favorably, the infiltration step can be omitted to reduce the manufacturing cost, and the wear resistance of the first metal member can be improved when used at a high temperature after joining. . Furthermore, the resistance value inside the first metal member can be effectively reduced at low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an engine cylinder head as a bonded metal member according to a basic embodiment 1;
FIG. 2 is a cross-sectional view schematically showing a joined state of a valve seat and a cylinder head body.
FIG. 3 is a cross-sectional view showing a shape of the valve seat before joining.
FIG. 4 is an explanatory view showing a procedure for joining a valve seat to a cylinder head body.
FIG. 5 is an explanatory view schematically showing a joining process of a valve seat and a cylinder head main body.
FIG. 6 is an explanatory view showing a state where a brazing material is coated on the surface portion of the valve seat in the brazing material bath by applying ultrasonic vibration.
FIG. 7 is a side view showing the joining device.
8A is a view taken in the direction of arrow VIII in FIG. 7, and FIG. 8B is a bottom view of the upper electrode.
FIG. 9 is a timing chart showing a method for controlling pressurization and energization.
FIG. 10 is a view corresponding to FIG. 9, illustrating another example of the pressurization control method.
FIG. 11 is a phase diagram of an Al—Zn alloy.
FIG. 12 is a view corresponding to FIG.
FIG. 13 is a graph showing a temperature change inside the valve seat due to pulse energization.
FIG. 14 is a view corresponding to FIG. 9, illustrating another example of the energization control method.
FIG. 15 is a cross-sectional view showing a state in which cooling water is sprayed on the inner peripheral surface portion of the valve seat.
FIG. 16 is a diagram corresponding to FIG.
FIG. 17 is a view corresponding to FIG. 9 and showing another example of the energization control method.
FIG. 18 is a cross-sectional view showing a state in which the valve seat is also pressed in the diameter reducing direction to suppress its thermal expansion.
FIG. 19 is a view corresponding to FIG. 3 showing another example of the shape of the valve seat.
20 is a cross-sectional view of the main part showing a state in which the valve seat and the cylinder head main body are joined by the joining device according to basic form 4. FIG.
FIG. 21 is a view corresponding to FIG. 4 showing a modification in which the shape before joining of the cylinder head main body is different from the basic forms 1 to 4;
22 is a cross-sectional view showing a piston of an engine as a bonded metal member according to basic form 5. FIG.
FIG. 23 is a cross-sectional view showing a main part of an engine cylinder block as a bonded metal member according to basic form 6;
FIG. 24 is a cross-sectional view of a principal part showing a state in which the valve seat and the cylinder head body are joined in the embodiment of the present invention.
FIG. 25 is a cross-sectional view showing a test piece used for joining in a basic example and a conventional example.
FIG. 26 is a sectional view showing a thin valve seat.
FIG. 27 is a cross-sectional view showing a thick valve seat.
FIG. 28 is a schematic cross-sectional view showing the outline of a punch load measurement test.
FIG. 29 is a graph showing results of a punching load measurement test in the valve seats of basic examples 1 to 5 and a conventional example.
FIG. 30 is a graph showing the relationship between the applied pressure during bonding and the extraction load.
FIG. 31 is a graph showing a change in hardness according to a distance from a joint surface portion of a test piece.
FIG. 32 is a graph showing changes in hardness before and after joining of the valve seat in continuous energization and pulse energization.
FIG. 33 is a graph showing a change in hardness according to a distance from a joint surface portion of a test piece in continuous energization and pulse energization.
FIG. 34 is a graph showing the results of a punching load measurement test in continuous energization and pulse energization.
FIG. 35 is an explanatory diagram showing an embedding amount y in an embedding amount measurement test.
FIG. 36 is a graph showing the relationship between the time from the start of pressurization and the embedding amount y.
FIG. 37 is a graph showing a change in hardness depending on a distance from a joint surface portion of a test piece when a valve seat is a sintered forged material and an infiltrated sintered material.
FIG. 38 is a cross-sectional view showing sheet shapes of Examples 1 to 3.
FIG. 39 is a cross-sectional view showing sheet shapes of Comparative Examples 1 to 4.
40 is a cross-sectional view of a principal part of a test piece used for joining Examples 1 and 2 and Comparative Examples 1 to 4. FIG.
41A shows a conventional electrode, and FIG. 41B shows an improved electrode.
FIG. 42 is a graph showing the results of a punching load measurement test in the valve seats of Examples and Comparative Examples.
43 is a photomicrograph showing the joined state between the valve seat and the test piece in Example 1. FIG.
44 is a photomicrograph showing the joined state between the valve seat and the test piece in Comparative Example 1. FIG.
45 is a photomicrograph showing the state after the punching load measurement test of Example 3. FIG.
FIG. 46 is a cross-sectional view showing a valve seat having an arcuate convex surface between the first and second joint surfaces.
47 is a photomicrograph showing a joined state between the valve seat and the test piece of FIG. 46. FIG.
FIG. 48 is a graph showing the results of measuring the punching load when performing hot-dip plating and when performing ultrasonic plating when forming the iron-side molten reaction layer and the brazing filler metal layer on the valve seat.
[Explanation of symbols]
  1 Cylinder head (joining metal member)
  2 Cylinder head body (second metal member)
  2a Joint surface
  2b port
  3 Valve seat (first metal member)
  3a First joint surface (inclined surface)
  3b Second joint surface (inclined surface)
  3f Third joint surface (inclined surface)
  5 Iron-side molten reaction layer (diffusion layer of brazing material and valve seat)
  6 Aluminum side molten reaction layer (diffusion layer of brazing material and cylinder head body)
  7 Brazing material layer
  14 Brazing bath

Claims (6)

The first metal member and the second metal member are plastically moved by pressing and moving the first metal member toward the second metal member by heating and pressurizing between the two metal members. A joining method for joining while flowing,
Prior to joining the two metal members, the joining surface portion of the first metal member is inclined in advance with respect to the pressing direction of the first metal member and continuously in the inclined direction so as to have two or more corner portions. A process comprising three or more inclined surfaces connected to each other;
The joining surface portion constituted by the inclined surface in the first metal member has a melting point lower than that of the first metal member and the second metal member and has a eutectic composition with the second metal member or a composition in the vicinity thereof. Forming the brazing material layer via a diffusion layer of the brazing material and the first metal member;
After the step of forming the brazing material layer, the first metal member and the second metal member are heated and pressurized to a temperature equal to or higher than the melting point of the brazing material due to heat generated by energization between the two metal members. Thus, the brazing material and the diffusion layer of the second metal member are formed so that the melting point of the brazing material is increased by increasing the proportion of the second metal member component in the brazing material, and the molten brazing material is used as both metal members. Forming an alloy part between the two diffusion layers in at least a part of the two diffusion layers by performing liquid phase diffusion bonding through the two diffusion layers while discharging from between the bonding surface portions of the two diffusion layers. ,
In the step of forming the brazing filler metal layer, the brazing filler metal is coated on the surface portion of the first metal member in the brazing filler metal bath by applying ultrasonic vibration, so that the brazing filler metal and the first metal member are diffused. A bonding metal member joining method, comprising: forming the brazing filler metal layer and the diffusion layer on the first metal member so that the thickness of the layer is 1 μm or less. In the joining method of the joining metal member according to claim 1,
There are three inclined surfaces, and a joining method for joining metal members. In the joining method of the joining metal member according to claim 2,
The inclination angle of the inclined surface having the smallest inclination angle with respect to the pressing direction of the first metal member is set to 30 to 40 °,
A joining method for joining metal members, wherein an inclination angle of an inclined surface having the largest inclination angle with respect to a pressing direction of the first metal member is set to 60 to 70 °. In the joining method of the joining metal member according to claim 1,
The first metal member is made of an Fe-based material,
The second metal member is made of an Al-based material,
The brazing material is made of a Zn-based material. In the joining method of the joining metal member according to claim 4,
The brazing material is made of a Zn-Al-based alloy having a Zn content of 92 to 98% by weight. In the joining method of the joining metal member according to any one of claims 1 to 5,
The first metal member is a sintered material formed by sintering a powder material in which Cu, which is a high electrical conductivity element, is dispersed .

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