JPH0524346B2 - - Google Patents
Info
- Publication number
- JPH0524346B2 JPH0524346B2 JP1273213A JP27321389A JPH0524346B2 JP H0524346 B2 JPH0524346 B2 JP H0524346B2 JP 1273213 A JP1273213 A JP 1273213A JP 27321389 A JP27321389 A JP 27321389A JP H0524346 B2 JPH0524346 B2 JP H0524346B2
- Authority
- JP
- Japan
- Prior art keywords
- ceramic
- piston
- metal member
- crown
- metal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000919 ceramic Substances 0.000 claims description 139
- 229910052751 metal Inorganic materials 0.000 claims description 123
- 239000002184 metal Substances 0.000 claims description 123
- 229910001141 Ductile iron Inorganic materials 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 4
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 description 7
- 230000006378 damage Effects 0.000 description 6
- 239000002131 composite material Substances 0.000 description 5
- 238000005304 joining Methods 0.000 description 5
- 229910052581 Si3N4 Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000003754 machining Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 2
- 238000005219 brazing Methods 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000001272 pressureless sintering Methods 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- -1 aluminum chromium molybdenum Chemical compound 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical compound [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000007586 pull-out test Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 229910002076 stabilized zirconia Inorganic materials 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2201/00—Metals
- F05C2201/04—Heavy metals
- F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
- F05C2201/0448—Steel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2251/00—Material properties
- F05C2251/04—Thermal properties
- F05C2251/042—Expansivity
Landscapes
- Pistons, Piston Rings, And Cylinders (AREA)
Description
本発明はセラミツクスクラウンをピストン頭部
に機械的手段により結合したセラミツクスクラウ
ンピストンとその製造方法に関するものである。
ジルコニア、窒化けい素、炭化けい素等のセラ
ミツクスは機械的強度、耐熱性、耐摩耗性にすぐ
れているため、ガスタービンエンジン部品、エン
ジン部品等の高温構造材料あるいは耐摩耗材料と
して注目されている。しかし、セラミツクスは一
般に硬くて、脆いため金属材料に比較して成形加
工性が劣る。また、靭性に乏しいため衝撃力に対
する抵抗が弱い。このため、セラミツクス材料の
みでエンジン部品のような機械部品を形成するこ
とは難かしく、一般には金属製部材とセラミツク
ス製部材とを結合した複合構造体としての形で用
いられる。
エンジン部品として使用されるセラミツクスク
ラウンピストンの一部を構成する金属製部材とセ
ラミツクス製部材の機械的結合構造としては焼ば
め構造（冷しばめ構造も含む）が知られている。
このようなセラミツクスクラウンピストンの結合
構造の例としては、例えば金属製ピストン本体と
セラミツクス製ピストンクラウンからなる断熱エ
ンジン用ピストンの結合構造として、セラミツク
ス製ピストンクラウンの周囲に金属製リングを焼
ばめし、その金属製リングの周囲にピストン本体
を鋳造した構造（特開昭56−122659号公報）があ
る。しかし焼ばめ構造（冷しばめも含む）にはつ
ぎのような欠点がある。
(1) 結合部材の加工に高精度が必要である。すな
わち、焼ばめ構造は結合部材の一方を加熱ない
しは冷却して、両部材間に嵌合可能な寸法差を
生ぜしめ、その寸法差を利用して両部材を嵌合
してなるものであるから、両部材の加工精度に
よつて、焼ばめ温度での寸法差および焼ばめ後
の締め代が決まる。加工精度が悪い場合には、
焼ばめ温度での寸法差の変動や締め代の変動が
大きくなり、安定した焼ばめができないばかり
か焼ばめ部の結合力も一定しなくなる。
(2) 寸法の小さな部品の結合ができない。すなわ
ち、焼ばめ温度での焼ばめ部材の熱膨張量は部
材寸法に比例する。小さい寸法の部材について
嵌合可能な寸法差を生ぜしめるためには、焼ば
め温度を高くしなければならない。焼ばめ温度
が高くなると、金属製部材の金属組織の変化、
相変態、軟化が生じたり、あるいはセラミツク
ス製部材との温度差が大きくなりすぎてセラミ
ツクス製部材に熱衝撃破壊が生ずるので好まし
くない。このため焼ばめ可能な寸法に制約があ
る。
本発明の特徴とする所は次の通りである。
第１発明
セラミツクス製部材がピストンクラウンの一
部、金属製部材がピストン本体の一部であつて、
前記金属製部材の中心に設けられた凹部又は貫通
孔に、セラミツクス製ピストンクラウンの中央に
設けられた凸部を圧入てなるセラミツクスピスト
ンクラウン・金属製部材結合体を金属ピストンの
頂部に結合したセラミツクスクラウンピストンに
おいて、前記結合体を構成する金属製部材の凹部
先端面とセラミツクス製ピストンクラウンの凸部
底面の間に、室温において下記の関係
（隙間の大きさ）＞（圧入部を構成する金属と
セラミツクスとの熱膨脹係数の差）×（圧入
距離）×（最高使用温度）
を満足する大きさの隙間が設けられていることを
特徴とするセラミツクスクラウンピストン。
第２発明
セラミツクス製部材がピストンクラウンの一
部、金属製部材がピストン本体の一部であつて、
前記金属製部材の中心に設けられた凹部又は貫通
孔に、セラミツクス製ピストンクラウンの中央に
設けられた凸部を圧入してなるセラミツクスクラ
ウン・金属製部材結合体を金属製ピストンの頂部
に結合するセラミツクスクラウンピストンの製造
法において、セラミツクス製部材に設けた凸部の
直径を金属製部材に設ける凹部の内径より0.5％
〜５％大きくするとともに、該凹部に対し凸部を
金属製部材の焼なまし温度以下の温度で圧入し、
該金属製部材の凹部先端面とセラミツクス製ピス
トンクラウンの凸部底面の間に、室温において下
記の関係
（隙間の大きさ）＞（圧入部を構成する金属と
セラミツクスとの熱膨脹係数の差）×（圧入
距離）×（最高使用温度）
を満足する大きさの隙間を設けることを特徴とす
るセラミツクスクラウンピストンの製造法。
ここでいう圧入とは、セラミツクス製部材に設
けた凸部を、その凸部直径より小径の金属製部材
に設けた凹部に荷重をかけて強制的に押し込んで
結合することである。
本発明のセラミツクスクラウンピストンではピ
ストン本体の一部を構成する金属製部材に設けら
れた凹部に、その凹部より大きな直径に加工され
たセラミツクス製ピストンクラウン上の凸部が強
制的に押込まれている。この場合に、セラミツク
ス製ピストンクラウン上の凸部と金属製部材の凹
部の寸法差が金属製部材の塑性変形および弾性変
形によつて吸収されるように金属製部材の凹部の
形状、寸法、肉厚などを決定するので、圧入部の
凹部と凸部の仕上げ寸法公差は厳しくする必要は
ない。
圧入時のセラミツクス製部材の凸部と金属製部
材の凹部の寸法差は凸部直径が凹部内径より0.5
％〜５％大きくするのが好ましく、金属製部材の
変形量や圧入に要する荷重を小さくするため0.5
％〜１％大きくするのがとくに好ましい。この寸
法差が0.5％以下では圧入部の結合力が不足し、
使用中に結合部が抜けるので好ましくない。寸法
差が５％以上になると圧入に必要な荷重が大きく
なりすぎて、圧入時にセラミツクス製部材の凸部
が折損するので好ましくない。
圧入は室温で行つてもよいし、金属製部材を加
熱するか、あるいは金属製部材とセラミツクス製
部材の両方を加熱して行つてもよい。加熱する場
合の温度は金属製部材の焼なまし温度以下の温度
である必要がある。圧入温度が金属製部材の焼な
まし温度以上の温度の場合は、圧入によつて金属
製部材の凹部に発生した内部応力と歪が緩和さ
れ、圧入部の結合力が減少するので好ましくな
い。
本発明のセラミツクスクラウンピストンでは金
属製部材上の凹部へのセラミツクス製部材上の凸
部の圧入により金属製部材の凹部内径が増加す
る。このため、金属製部材としては、焼なまし処
理済の材料を使用するのが望ましい。硬化処理し
た金属製部材を使用する場合には金属製部材の凹
部内径が変形できる寸法、形状にする必要があ
る。
図面により本発明をさらに詳しく説明する。
第１図は本発明のセラミツクスクラウンピスト
ンの一具体例の構造の断面図を示したものであ
る。
第２図は第１図のセラミツクスクラウンピスト
ンのセラミツクス製クラウン上の凸部とピストン
本体の一部を構成する金属製部材上の凹部との結
合部の説明図を示したものである。
第１図は一端にフランジ部を有する金属製部材
２に設けられた貫通孔３に、この貫通孔より大径
のセラミツクスクラウン１の凸部４を該凸部の底
面と金属製部材上のフランジ端部面との間に所定
の大きさの隙間を残して圧入により一体的に結合
したのち、この金属製部材２の胴部外周にネジ２
Ａを設けたセラミツクス製クラウン・金属製部材
結合体を、ピストン本体１９の頂部に設けられた
この結合体をはめ込み可能な一部貫通孔からなる
空所にはめ込んで、該貫通孔に設けたネジ１９Ａ
と前記結合体の金属製部材２の胴部外周に設けた
ネジ２Ａで固定したところのピストンクラウンが
セラミツクスよりなり、ピストン本体が金属から
なる断熱エンジン用ピストンである。第３図のピ
ストンの組立に際しては、セラミツクス製ピスト
ンクラウンの下面とピストン本体に設けられた空
所の上面との間にも隙間を設けて、ピストン本体
の熱膨脹によりセラミツクス製ピストンクラウン
の破損を防止することが必要である。
第２図は第１図のセラミツクス製クラウン・金
属製部材結合体の結合部の詳細を説明する断面図
である。本発明では、セラミツクスクラウンピス
トンの使用温度において、セラミツクス製クラウ
ン１の凸部４の底面７と金属製部材上の凹部３の
端面６との間に隙間５を存在させる。上記隙間は
セラミツクス製部材上の凸部底面と金属製部材上
の凹部端面の間にスペーサーを介在させた圧入あ
るいは圧入を圧入部の最高使用温度以上の温度で
行うことなどにより得られる。両部材の圧入を容
易にするため、セラミツクス製部材上の凸部先端
と、金属製部材の凹部入口にはテーパーをつけ
る。
なお、第２図はセラミツクス製クラウン１の凸
部４が、胴部の一端に胴部直径より大径のフラン
ジ部９を有する円筒状金属製部材２の凹部３に圧
入された構造の一例が示されている。このフラン
ジ９は、金属製部材２の胴部外周に設けたネジ２
Ａと第１図記載のピストン本体１９の頂部に設け
た貫通孔のネジ１９Ａとを締めつけて、セラミツ
クス製クラウン１とピストン本体１９を一体的に
結合する場合に、ネジの締めつけによつて生ずる
軸力や金属製部材２の胴部の熱膨脹とこの胴部上
に組込まれたピストン本体の熱膨脹差による応力
がセラミツクス製クラウン１に作用するのを防
ぎ、セラミツクス製クラウン１の破損を防止す
る。また、第１図の如き形状のピストンの組立に
際しては、このフランジ部がはめ込まれる部分の
深さをフランジ部の厚さより小さくすることで、
セラミツクス製ピストンクラウンの下面とピスト
ン本体に設けられた空所の上面との間に、隙間を
設けることができる。
即ち、圧入による結合構造においては、金属が
セラミツクスを締めつける面圧は第３図に示すと
おり圧入部の両端が高い。このような結合のセラ
ミツクスクラウンピストンは運転中ピストンクラ
ウン側の方が温度が高くなるのでＢ部よりＡ部の
方が高温となる。また、金属はセラミツクスより
熱膨脹係数が大きいことから、径方向での金属と
セラミツクスの熱膨脹差は低温であるＢ部よりも
高温であるＡ部の方が大となる。その結果、Ｂ部
よりもＡ部の締め代が大きく減少し、面圧はＡ部
よりＢ部の方が高くなり、セラミツクスと金属の
熱膨脹係数の差による金属の伸びはＢが支点とな
り、金属部材の端部６がセラミツクス部材の底部
７を押しつけることにより破損することを見出し
た。破損する箇所はセラミツクス部材の凸部４の
根本部又は底面側に位置する圧入部のいずれかで
ある。
そのため、隙間５の大きさは次の関係を満足す
る大きさであればよい。
（隙間５の大きさ）＞（圧入部を構成する金属
部材とセラミツクス部材の熱膨脹係数差）
×（圧入距離）×（最高使用温度）
なお、上記圧入距離は第３図のＢ点から金属部
材の端部６までの距離を意味する。
圧入による結合は、焼きばめあるいはロウ付け
にくらべると金属部材の軸方向での伸びが大き
い。
なぜならば、荷重を加え強制的に圧入した時、
金属製凹部内表面の円周方向の加工痕がセラミツ
クス凸部により、ならされ軸方向の摩擦係数が低
下するのに対し、焼きばめでは凹部内表面の加工
痕がそのまま残り軸方向の摩擦係数も低下しない
からと考えられる。
又、ロウ付けにおいては、温度差が生じても伸
びの支点がＢとはならないためである。
本発明のセラミツクスクラウンピストンのセラ
ミツクス製クラウン・金属製部材結合部を構成す
る金属とセラミツクスの熱膨脹係数は等しいこと
が望ましい。しかし、一般には金属の熱膨脹係数
の方がセラミツクスの熱膨脹係数より大きい。し
たがつて、室温でセラミツクス製部材の凸部４の
底面７と金属製部材の凹部３の端面６の間に隙間
が存在しない場合には、圧入部の温度が上昇する
と、金属製部材とセラミツクス製部材の熱膨脹差
のためセラミツクス部材が破損する。この問題
は、本発明のセラミツクスクラウンピストンの隙
間５を設けるこで解決される。
本発明では、この隙間の間に、弾性体あるいは
圧入後の仕上げ加工により生じたばりなどセラミ
ツクス製部材と金属製部材の熱膨脹差による応力
で実質的に変形可能な物体が存在する場合も隙間
が存在するものと見なす。
本発明のセラミツクスクラウンピストンを構成
するセラミツクス材料は窒化珪素、炭化けい素、
部分安定化ジルコニア等から本発明のセラミツク
スクラウンピストンの使用目的に応じて選択すれ
ばよい。
実施例 １
常圧焼結法で作製した窒化珪素丸棒から半径
1.5mmのＲで滑らかにつながつている直径3.1mm、
長さ20mmの凸部を有するセラミツクス製部材を作
製した。この凸部先端にはさらに長さ2.0mmのテ
ーパー部が設けられている。また、焼なましたク
ロムモリブデン鋼（JIS−SCM 435）丸棒の一端
に内径3.0mm、深さ25mmの凹部と残りの一端にネ
ジ部を設けた胴径直径５mmの金属製部材を作製し
た。この凹部入口には、セラミツクス製部材の凸
部の圧入を容易にするため、深さ2.5mmのテーパ
ーが設けてある。この金属製部材の凹部にセラミ
ツクス製部材の凸部を20℃で圧入し、金属製部材
凹部先端とセラミツクス製部材凸部底面の隙間
（第４図のＣ）が0.2mm、圧入距離19.8mm（結合体
Ａ）と隙間が０mm、圧入距離20mm（結合体Ｂ）で
ある第４図に示す形状の金属・セラミツクス結合
体を作製した。この金属・セラミツクス結合体を
加熱炉に入れて300℃まで昇温したところ結合体
Ａには何ら異常は認められなかつた。しかし、結
合体Ｂは昇温途中の200℃でセラミツクス製部材
のＲ部から破損した。
この結果から、第２図のセラミツクス製クラウ
ンと金属製部材の結合体の場合もセラミツクス製
クラウン１の凸部４の底面７と金属製部材上の凹
部３の端面６との間に隙間５が存在しなければ、
使用温度への昇温途中でセラミツクス製クラウン
１から凹部４へつながるＲ部で破損することが容
易に予測できる。
実施例 ２
常圧焼結法で作製した窒化珪素丸棒から半径
1.5mmのＲで滑らかにつながり第１表に示す大き
さの直径とその直径部の長さが20mmの凸部を有す
るセラミツクス製部材を作製した。また、焼なま
したアルミニウムクロムモリブデン鋼（JIS−
SACM 645）丸棒の一端に入口部のテーパー深
さ2.5mm、第１表に示す直径、全長30mmからなる
凹部、残りの一端にネジを設けた金属製部材を作
製した。この金属製部材の凹部にセラミツクス製
部材の凸部を第１表に示す条件で圧入して第４図
に示す形状の金属・セラミツクス結合体を作製し
た。この金属・セラミツクス結合体を第５図に示
すような治具を用い、第５図に図示の部分を加熱
炉に入れて、第１表に示す温度に加熱し、上下方
向に引抜いて結合部の引抜に要する荷重を測定し
た。得られた結果を第１表に示した。
No.１とNo.２はセラミツクス製部材が第４図Ｒ部
で破損したので、結合部の引抜に要する荷重（結
合力）がセラミツクス製部材のＲ部の破断荷重以
上であることは明らかである。
The present invention relates to a ceramic crown piston in which a ceramic crown is mechanically connected to a piston head, and a method for manufacturing the same. Ceramics such as zirconia, silicon nitride, and silicon carbide have excellent mechanical strength, heat resistance, and wear resistance, so they are attracting attention as high-temperature structural materials or wear-resistant materials for gas turbine engine parts, engine parts, etc. . However, since ceramics are generally hard and brittle, their moldability is inferior to that of metal materials. In addition, since it has poor toughness, it has low resistance to impact forces. For this reason, it is difficult to form mechanical parts such as engine parts only from ceramic materials, and they are generally used in the form of a composite structure in which metal members and ceramic members are combined. A shrink fit structure (including a cold fit structure) is known as a mechanical connection structure between a metal member and a ceramic member that constitute a part of a ceramic crown piston used as an engine component.
An example of such a joining structure of a ceramic crown piston is, for example, a joining structure of a piston for an insulated engine consisting of a metal piston body and a ceramic piston crown, in which a metal ring is shrink-fitted around the ceramic piston crown. There is a structure (Japanese Unexamined Patent Publication No. 122659/1983) in which the piston body is cast around the metal ring. However, shrink fit structures (including cold fit) have the following drawbacks. (1) High precision is required for processing the joining parts. In other words, the shrink-fit structure heats or cools one of the joining members to create a dimensional difference between the two members that allows them to fit together, and then uses that dimensional difference to fit the two members together. Therefore, the dimensional difference at the shrink fit temperature and the interference after shrink fit are determined by the processing accuracy of both members. If machining accuracy is poor,
Fluctuations in the dimensional difference and fluctuations in interference at the shrink fit temperature become large, making it impossible to perform a stable shrink fit, and also making the bonding force of the shrink fit part inconsistent. (2) Parts with small dimensions cannot be joined. That is, the amount of thermal expansion of the shrink-fit member at the shrink-fit temperature is proportional to the member dimensions. In order to create a fitable dimensional difference for small sized parts, the shrink fit temperature must be increased. As the shrink fit temperature increases, changes in the metal structure of the metal member,
This is not preferable because phase transformation or softening may occur, or the temperature difference with the ceramic member may become too large, resulting in thermal shock destruction of the ceramic member. For this reason, there are restrictions on the dimensions that can be shrink-fitted. The features of the present invention are as follows. First invention The ceramic member is a part of the piston crown, the metal member is a part of the piston body,
A ceramic piston crown/metal member assembly is bonded to the top of a metal piston, in which a protrusion provided at the center of a ceramic piston crown is press-fitted into a recess or through hole provided at the center of the metal member. In the crowned piston, the following relationship exists at room temperature between the top surface of the concave part of the metal member constituting the above-mentioned joint and the bottom surface of the convex part of the ceramic piston crown. A ceramic crown piston characterized by having a gap of a size that satisfies the following: (difference in coefficient of thermal expansion with ceramic) x (press-fit distance) x (maximum operating temperature). Second invention The ceramic member is a part of the piston crown, the metal member is a part of the piston body,
A ceramic crown/metal member assembly is joined to the top of the metal piston by press-fitting a protrusion provided at the center of the ceramic piston crown into a recess or through hole provided at the center of the metal member. In the manufacturing method of ceramic crown pistons, the diameter of the convex part provided on the ceramic member is 0.5% of the inner diameter of the recessed part provided on the metal member.
~5% larger, and a convex part is press-fitted into the concave part at a temperature below the annealing temperature of the metal member,
The following relationship exists at room temperature between the tip of the concave part of the metal member and the bottom of the convex part of the ceramic piston crown (size of gap) > (difference in coefficient of thermal expansion between the metal and ceramics constituting the press-fit part) x A method of manufacturing a ceramic crown piston characterized by providing a gap of a size that satisfies (press-fit distance) x (maximum operating temperature). Press-fitting here means that a protrusion provided on a ceramic member is forcibly pushed into a recess provided in a metal member having a smaller diameter than the diameter of the protrusion, thereby joining the protrusion to the ceramic member. In the ceramic crown piston of the present invention, a convex portion on the ceramic piston crown that is machined to have a larger diameter than the concave portion is forcibly pushed into a concave portion provided in a metal member that constitutes a part of the piston body. . In this case, the shape, size, and thickness of the recess of the metal member must be adjusted so that the difference in size between the convex part on the ceramic piston crown and the recess of the metal member is absorbed by the plastic deformation and elastic deformation of the metal member. Since the thickness etc. are determined, it is not necessary to have strict finishing tolerances for the concave and convex portions of the press-fit portion. The dimensional difference between the convex part of the ceramic part and the concave part of the metal part during press-fitting is such that the diameter of the convex part is 0.5% larger than the inner diameter of the concave part.
It is preferable to increase it by 5% to 0.5% in order to reduce the amount of deformation of the metal member and the load required for press-fitting.
It is particularly preferable to increase it by 1% to 1%. If this dimensional difference is less than 0.5%, the bonding force of the press-fit part will be insufficient,
This is not preferable because the joint may come off during use. If the dimensional difference is 5% or more, the load required for press-fitting becomes too large and the convex portion of the ceramic member may break during press-fitting, which is not preferable. Press-fitting may be performed at room temperature, or may be performed by heating the metal member or by heating both the metal member and the ceramic member. The temperature when heating needs to be below the annealing temperature of the metal member. If the press-fitting temperature is higher than the annealing temperature of the metal member, it is not preferable because the internal stress and strain generated in the recessed part of the metal member due to press-fitting will be alleviated, and the bonding force of the press-fitted part will be reduced. In the ceramic crown piston of the present invention, the inner diameter of the recess of the metal member is increased by press-fitting the protrusion on the ceramic member into the recess on the metal member. For this reason, it is desirable to use an annealed material as the metal member. When using a hardened metal member, it is necessary that the inner diameter of the recessed part of the metal member be of a size and shape that can be deformed. The present invention will be explained in more detail with reference to the drawings. FIG. 1 shows a sectional view of the structure of a specific example of the ceramic crown piston of the present invention. FIG. 2 is an explanatory view of the connection portion between the convex portion on the ceramic crown of the ceramic crown piston shown in FIG. 1 and the concave portion on the metal member constituting a part of the piston body. FIG. 1 shows a through hole 3 provided in a metal member 2 having a flange at one end, and a convex portion 4 of a ceramic crown 1 having a larger diameter than the through hole between the bottom surface of the convex portion and the flange on the metal member. After being integrally joined by press fitting with a gap of a predetermined size left between the end face and the end surface, a screw 2 is attached to the outer periphery of the body of this metal member 2.
The ceramic crown/metal member assembly provided with A is fitted into a hollow formed by a partially through hole provided at the top of the piston body 19 into which this assembly can be fitted, and a screw provided in the through hole is inserted. 19A
This is a piston for an adiabatic engine in which the piston crown, which is fixed with a screw 2A provided on the outer periphery of the body of the metal member 2 of the above-mentioned combined body, is made of ceramics, and the piston body is made of metal. When assembling the piston shown in Figure 3, a gap is also provided between the lower surface of the ceramic piston crown and the upper surface of the cavity provided in the piston body to prevent damage to the ceramic piston crown due to thermal expansion of the piston body. It is necessary to. FIG. 2 is a sectional view illustrating details of the joint portion of the ceramic crown/metal member assembly shown in FIG. 1. FIG. In the present invention, at the operating temperature of the ceramic crown piston, a gap 5 is created between the bottom surface 7 of the convex portion 4 of the ceramic crown 1 and the end surface 6 of the concave portion 3 on the metal member. The above-mentioned gap can be obtained by press-fitting a spacer between the bottom surface of a convex portion on a ceramic member and an end surface of a concave portion on a metal member, or by performing press-fitting at a temperature higher than the maximum operating temperature of the press-fit portion. In order to facilitate press-fitting of both members, the tip of the protrusion on the ceramic member and the entrance of the recess on the metal member are tapered. FIG. 2 shows an example of a structure in which the convex portion 4 of the ceramic crown 1 is press-fitted into the recess 3 of a cylindrical metal member 2 which has a flange portion 9 having a diameter larger than the diameter of the body at one end of the body. It is shown. This flange 9 is a screw 2 provided on the outer periphery of the body of the metal member 2.
When the ceramic crown 1 and the piston body 19 are integrally connected by tightening A and the screw 19A of the through hole provided at the top of the piston body 19 shown in FIG. This prevents force and stress due to the difference in thermal expansion between the body of the metal member 2 and the piston body assembled on the body from acting on the ceramic crown 1, thereby preventing damage to the ceramic crown 1. Furthermore, when assembling a piston having the shape shown in Fig. 1, by making the depth of the part into which the flange part is fitted smaller than the thickness of the flange part,
A gap can be provided between the lower surface of the ceramic piston crown and the upper surface of the cavity provided in the piston body. That is, in a bonding structure by press-fitting, the surface pressure at which the metal tightens the ceramic is high at both ends of the press-fitting part, as shown in FIG. In a ceramic crown piston connected in this way, the temperature on the piston crown side is higher during operation, so the temperature in the A part is higher than in the B part. Furthermore, since metal has a larger coefficient of thermal expansion than ceramics, the difference in thermal expansion between metal and ceramics in the radial direction is greater in section A, which is at a high temperature, than in section B, which is at a low temperature. As a result, the interference in part A is greatly reduced than in part B, the surface pressure is higher in part B than in part A, and the elongation of the metal due to the difference in the coefficient of thermal expansion between ceramics and metal is at B, and the metal It has been found that the end 6 of the part can be damaged by pressing against the bottom 7 of the ceramic part. The location where the damage occurs is either the root portion of the convex portion 4 of the ceramic member or the press-fit portion located on the bottom surface side. Therefore, the size of the gap 5 may be any size that satisfies the following relationship. (Size of gap 5) > (difference in coefficient of thermal expansion between metal member and ceramic member that constitute the press-fit part)
× (Press-fitting distance) × (Maximum operating temperature) The above-mentioned press-fitting distance means the distance from point B in FIG. 3 to the end 6 of the metal member. When joining by press fitting, the elongation of the metal members in the axial direction is greater than when using shrink fitting or brazing. This is because when force is applied and press-fitted,
The machining marks on the inner surface of the metal recess in the circumferential direction are evened out by the ceramic convex part, reducing the friction coefficient in the axial direction, whereas in shrink fitting, the machining marks on the inner surface of the recess remain as they are and the coefficient of friction in the axial direction decreases. This is thought to be because it does not decrease. Further, in brazing, the fulcrum of elongation does not become B even if a temperature difference occurs. It is desirable that the coefficient of thermal expansion of the metal constituting the ceramic crown/metal member joint portion of the ceramic crown piston of the present invention and the ceramic be equal. However, the coefficient of thermal expansion of metals is generally larger than that of ceramics. Therefore, if there is no gap between the bottom surface 7 of the protrusion 4 of the ceramic member and the end surface 6 of the recess 3 of the metal member at room temperature, when the temperature of the press-fitted part increases, the metal member and the ceramic Ceramic parts break due to differential thermal expansion of the manufactured parts. This problem is solved by providing the gap 5 in the ceramic crown piston of the invention. In the present invention, the gap can be maintained even when there is an elastic body or an object that can be substantially deformed due to the stress caused by the difference in thermal expansion between the ceramic member and the metal member, such as a burr caused by finishing processing after press-fitting, between the gap. Consider it to exist. The ceramic materials constituting the ceramic crown piston of the present invention include silicon nitride, silicon carbide,
The material may be selected from partially stabilized zirconia and the like depending on the intended use of the ceramic crown piston of the present invention. Example 1 Radius from silicon nitride round bar manufactured by pressureless sintering method
3.1mm in diameter smoothly connected with 1.5mm radius,
A ceramic member having a convex portion with a length of 20 mm was manufactured. A tapered portion with a length of 2.0 mm is further provided at the tip of this convex portion. In addition, a metal member with a body diameter of 5 mm was prepared by providing a recess with an inner diameter of 3.0 mm and a depth of 25 mm at one end of an annealed chromium molybdenum steel (JIS-SCM 435) round bar, and a threaded portion at the other end. . A taper with a depth of 2.5 mm is provided at the entrance of this recess to facilitate press-fitting of the protrusion of the ceramic member. The convex part of the ceramic member was press-fitted into the concave part of this metal member at 20°C, and the gap between the tip of the concave part of the metal member and the bottom of the convex part of the ceramic member (C in Fig. 4) was 0.2 mm, and the press-fit distance was 19.8 mm ( A metal/ceramic bonded body having the shape shown in FIG. 4 was prepared with a gap of 0 mm and a press-fit distance of 20 mm (bond body B) from bonded body A). When this metal/ceramics composite was placed in a heating furnace and heated to 300°C, no abnormalities were observed in composite A. However, the bonded body B broke at the R portion of the ceramic member at 200° C. during the temperature rise. From this result, it can be seen that in the case of the combined body of the ceramic crown and the metal member shown in FIG. If it doesn't exist,
It can be easily predicted that damage will occur at the R portion connecting the ceramic crown 1 to the recess 4 during heating to the operating temperature. Example 2 Radius from silicon nitride round bar manufactured by pressureless sintering method
A ceramic member was produced which had a convex part connected smoothly with a radius of 1.5 mm, the diameter shown in Table 1, and the length of the diameter portion of the convex part of 20 mm. In addition, annealed aluminum chromium molybdenum steel (JIS-
SACM 645) A metal member was fabricated with a concave portion having a taper depth of 2.5 mm at the entrance, a diameter shown in Table 1, and a total length of 30 mm at one end of a round bar, and a screw at the other end. The protrusions of the ceramic member were press-fitted into the recesses of the metal member under the conditions shown in Table 1 to produce a metal-ceramic composite having the shape shown in FIG. 4. Using a jig as shown in Fig. 5, this metal/ceramic bonded body is placed in a heating furnace with the parts shown in Fig. 5 heated to the temperature shown in Table 1, and then pulled out in the vertical direction to form the joint. The load required for pulling out was measured. The results obtained are shown in Table 1. In No. 1 and No. 2, the ceramic members were damaged at the R section in Figure 4, so it is clear that the load (bonding force) required to pull out the joint is greater than the breaking load at the R section of the ceramic member. be.
【表】
第１表から明らかなように、本発明の金属・セ
ラミツクス結合体は300℃においても大きな結合
力を有している。
これに対して、本発明の範囲外のものを示した
比較例では、金属製部材の凹部にセラミツクス製
部材の凸部が圧入不可能であつたり、圧入が可能
でも結合力の弱いものしか得られない。比較例No.
101〜No.103はそれぞれ金属製部材の硬さ、金属製
部材上の凹部外壁の厚さ、セラミツクス製部材上
の凸部寸法と金属製部材上の凹部寸法の差がいず
れも本発明の範囲より大きいため、圧入時にセラ
ミツクス製部材の凸部が破損したものである。
また、比較例No.104はセラミツクス製部材の凸
部寸法と金属製部材の凹部寸法の差が本発明の範
囲より小さい場合の例であるが、この場合には結
合力が弱くて低い荷重で結合部が抜けたものであ
る。
なお、セラミツクス製部材上の凸部寸法と金属
製部材上の凹部寸法が第１表記載の寸法比を保つ
た状態で大きくなつた場合には、結合部の引抜き
に要する荷重が寸法増加の割合に応じて増加する
のみでその他の傾向は本実施例の結果に従う。
実施例 ３
5.2％のY2O3を含む部分安定化ジルコニアセラ
ミツクスで、板面中央に直径15mm、長さ15mmの凸
部４を有する直径69mm、厚さ３mmのピストンクラ
ウン１を作製した。また、球状黒鉛鋳鉄で外径35
mmのフランジ部９、直径25mmの胴部、内径14.8
mm、全長20mmの凹部３を有する金属製部材２を作
製した。この金属製部材のフランジ部上面６とピ
ストンクラウンの凸部４の底面７の間に厚さ
50μmのニツケル箔を介在させて凹部３にピスト
ンクラウンの凸部４を500℃で圧入したのち室温
に冷却後ニツケル箔を除去し、金属製部材のフラ
ンジ部上面６とピストンクラウンの凸部４の底面
７の間に約80μmの隙間５を有するセラミツクス
製ピストンクラウンと金属製部材の結合体を作製
した。
一方、直径70mmの球状黒鉛鋳鉄製ピストンのピ
ストンクラウンの一部にこのセラミツクスピスト
ンクラウン・金属製部材結合体をはめ込み可能な
一部貫通孔からなる空所を設けた。ついで、この
貫通孔の内表面と前記結合体の金属製部材胴部上
にそれぞれネジ部１９Ａと２Ａを設け、これらの
ネジ部を介して第１図に示す形状のピストンクラ
ウンの一部が部分安定化ジルコニアセラミツク
ス、ピストン本体が球状黒鉛鋳鉄である断熱エン
ジン用ピストンを作製した。このピストンは直径
70mm、ストローク75mm、回転数2200rpmのデイー
ゼルエンジンで10時間運転しても何ら異常は認め
られなかつた。
なお、比較のため、ピストンクラウンの凸部４
を金属製部材の凹部３に室温で圧入して、金属製
部材のフランジ部上面６とピストンクラウンの凸
部４の底面７の間に隙間の存在しないセラミツク
スピストンクラウンと金属製部材の結合体を作製
した。この結合体を使用して第１図に示す形状の
ピストンクラウンの一部が部分安定化ジルコニア
セラミツクス、ピストン本体が球状黒鉛鋳鉄であ
る断熱エンジン用ピストンを作製した。このピス
トンを加熱炉中で500℃まで昇温したところピス
トンクラウンの凸部４で破損した。
以上述べたことから明らかなとおり、本発明の
セラミツクスクラウンピストンはセラミツクス製
部材に設けた凸部をその凸部直径より小径の金属
製部材に設けた凹部に、荷重をかけて強制的に押
し込むとともに、本発明のセラミツクスクラウン
ピストンとの結合体の使用温度において、セラミ
ツクス製部材上の凸部底面と金属製部材上の凹部
端面との間に隙間が存在するように嵌合するもの
であるから、セラミツクス製部材と金属製部材の
加工精度は焼ばめの場合のような高精度を必要と
せず、結合体の寸法上の制約もない。さらにま
た、圧入部のセラミツクスと金属の熱膨脹係数の
差による破損も防止できる。
また、金属製ピストンのピストンクラウンに、
本発明のセラミツクスピストンクラウンと金属製
部材の結合体のはめ込み可能な空所を設け、この
空所内に設けたネジと、本発明のセラミツクスピ
ストンクラウンと金属製部材の結合体の金属製部
材の胴部に設けたネジとを固定したピストンクラ
ウンの一部がセラミツクス、ピストン本体が金属
からなる断熱エンジン用ピストンは高温の燃焼ガ
スにさらされるピストンクラウンを断熱性の高い
セラミツクスとすることができるので、容易に断
熱効果の高いピストンを作ることもできる。
このように、本発明のセラミツクスピストンク
ラウンと金属製部材の結合体よりなるセラミツク
スクラウンピストンはセラミツクスの耐熱性、断
熱性、高温強度ならびに耐摩耗性を生かして優れ
たピストンとすることができる。[Table] As is clear from Table 1, the metal-ceramic composite of the present invention has a large bonding strength even at 300°C. On the other hand, in comparative examples outside the scope of the present invention, it is impossible to press the protrusion of the ceramic member into the recess of the metal member, or even if press-fit is possible, only a weak bonding force is obtained. I can't. Comparative example No.
101 to No. 103, the hardness of the metal member, the thickness of the outer wall of the recess on the metal member, and the difference between the dimension of the convex part on the ceramic member and the dimension of the recess on the metal member are all within the scope of the present invention. Because it was larger, the convex part of the ceramic member was damaged during press-fitting. Comparative Example No. 104 is an example in which the difference between the convex dimension of the ceramic member and the concave dimension of the metal member is smaller than the scope of the present invention, but in this case, the bonding force is weak and a low load is required. The joint has come loose. In addition, if the dimensions of the convex part on the ceramic member and the dimension of the concave part on the metal member increase while maintaining the dimensional ratio listed in Table 1, the load required to pull out the joint will increase at the rate of increase in dimension. The other trends follow the results of this example. Example 3 A piston crown 1 having a diameter of 69 mm and a thickness of 3 mm and having a convex portion 4 of 15 mm in diameter and 15 mm in length at the center of the plate surface was manufactured using partially stabilized zirconia ceramics containing 5.2% Y 2 O 3 . In addition, it is made of spheroidal graphite cast iron with an outer diameter of 35 mm.
mm flange part 9, body diameter 25 mm, inner diameter 14.8
A metal member 2 having a recess 3 with a total length of 20 mm and a total length of 20 mm was produced. The thickness between the upper surface 6 of the flange portion of this metal member and the bottom surface 7 of the convex portion 4 of the piston crown
The convex part 4 of the piston crown was press-fitted into the concave part 3 at 500°C with a 50 μm nickel foil interposed therebetween, and after cooling to room temperature, the nickel foil was removed, and the upper surface 6 of the flange part of the metal member and the convex part 4 of the piston crown were pressed. A combined body of a ceramic piston crown and a metal member having a gap 5 of about 80 μm between the bottom surface 7 was produced. On the other hand, in a part of the piston crown of a spheroidal graphite cast iron piston with a diameter of 70 mm, a cavity consisting of a partially through hole into which this ceramic piston crown/metal member assembly could be fitted was provided. Next, threaded portions 19A and 2A are provided on the inner surface of the through hole and on the body of the metal member of the combined body, respectively, and a portion of the piston crown having the shape shown in FIG. 1 is partially inserted through these threaded portions. We fabricated a piston for an insulated engine made of stabilized zirconia ceramics and a piston body made of spheroidal graphite cast iron. This piston has a diameter
No abnormalities were observed even after 10 hours of operation with a diesel engine with a 70 mm diameter, 75 mm stroke, and 2200 rpm. For comparison, the convex portion 4 of the piston crown
is press-fitted into the recess 3 of the metal member at room temperature to form a combined body of the ceramic piston crown and the metal member in which there is no gap between the upper surface 6 of the flange portion of the metal member and the bottom surface 7 of the convex portion 4 of the piston crown. Created. Using this combined body, a piston for an adiabatic engine having the shape shown in FIG. 1 was manufactured, in which a portion of the piston crown was made of partially stabilized zirconia ceramics and the piston body was made of spheroidal graphite cast iron. When this piston was heated to 500° C. in a heating furnace, it broke at the convex portion 4 of the piston crown. As is clear from the above, the ceramic crown piston of the present invention forcibly pushes a convex portion provided on a ceramic member into a concave portion provided on a metal member having a smaller diameter than the convex portion diameter. , because at the operating temperature of the combined body with the ceramic crown piston of the present invention, there is a gap between the bottom surface of the convex part on the ceramic member and the end face of the concave part on the metal member, The machining accuracy of the ceramic member and the metal member does not require high accuracy as in the case of shrink fitting, and there are no restrictions on the dimensions of the combined body. Furthermore, damage caused by the difference in coefficient of thermal expansion between the ceramic and metal of the press-fitted part can be prevented. In addition, on the piston crown of the metal piston,
A cavity is provided into which the combination of the ceramic piston crown and the metal member of the present invention can be fitted, and a screw provided in the cavity and the body of the metal member of the combination of the ceramic piston crown and the metal member of the present invention are provided. In the case of an insulated engine piston, where the piston crown, which is fixed to the screw provided in the piston, is made of ceramics and the piston body is made of metal, the piston crown, which is exposed to high-temperature combustion gas, can be made of highly insulating ceramics. It is also possible to easily make pistons with high heat insulation effects. As described above, the ceramic crown piston of the present invention, which is a combination of a ceramic piston crown and a metal member, can be made into an excellent piston by taking advantage of the heat resistance, heat insulation, high temperature strength, and wear resistance of ceramics.
第１図は本発明のセラミツクスクラウンピスト
ンの一具体例の構造の断面図を示す説明図、第２
図は第１図のセラミツクスクラウンピストンのセ
ラミツク製クラウン上の凸部とピストン本体に一
部を構成する金属製部材上の凹部との結合部の説
明図、第３図は、本発明のセラミツクスクラウン
ピストンの圧入部の一具体例の構造の断面図およ
び圧入部の面圧を示す説明図。第４図は本発明の
セラミツクスクラウンピストンの一部を構成する
セラミツクスピストン・金属製部材結合部の圧入
条件を決定するための試験用結合部の説明図、第
５図は、上記試験用結合体の引抜試験法を示す説
明図である。
１…セラミツクス製部材、２…金属製部材、２
Ａ…金属製部材胴部のネジ、３…金属製部材の凹
部又は貫通孔、４…セラミツクス部材の凸部、５
…凹部端面と凸部底面の隙間、６…凹部の端面、
７…凸部底面、９…フランジ部、１９…金属製ピ
ストン本体、１９Ａ…ピストン本体貫通孔内面の
ネジ、３１…プルロツド、３２…引抜用ツカミ
具。
FIG. 1 is an explanatory diagram showing a cross-sectional view of the structure of a specific example of the ceramic crown piston of the present invention, and FIG.
The figure is an explanatory view of the joint between the convex part on the ceramic crown of the ceramic crown piston shown in Fig. 1 and the concave part on the metal member that constitutes a part of the piston body, and Fig. 3 shows the ceramic crown of the present invention. FIG. 2 is a cross-sectional view of a structure of a specific example of a press-fitting portion of a piston, and an explanatory diagram showing surface pressure of the press-fitting portion. FIG. 4 is an explanatory diagram of a test joint for determining the press-fitting conditions of the ceramic piston/metal member joint that constitutes a part of the ceramic crown piston of the present invention, and FIG. FIG. 2 is an explanatory diagram showing a pullout test method. 1...Ceramics member, 2...Metal member, 2
A... Screw on the body of the metal member, 3... Recess or through hole in the metal member, 4... Convex part in the ceramic member, 5
...Gap between the end face of the concave part and the bottom face of the convex part, 6...The end face of the concave part,
7... Bottom surface of the convex portion, 9... Flange portion, 19... Metal piston body, 19A... Screw on the inner surface of the piston body through hole, 31... Pull rod, 32... Pulling hook.
Claims (1)
部、金属製部材がピストン本体の一部であつて、
前記金属製部材の中心に設けられた凹部又は貫通
孔に、セラミツクス製ピストンクラウンの中央に
設けられた凸部を圧入してなるセラミツクスピス
トンクラウン・金属製部材結合体を金属ピストン
の頂部に結合したセラミツクスクラウンピストン
において、前記結合体を構成する金属製部材の凹
部先端面とセラミツクス製ピストンクラウンの凸
部底面の間に、室温において下記の関係 （隙間の大きさ）＞（圧入部を構成する金属と
セラミツクスとの熱膨脹係数の差）×（圧入
距離）×（最高使用温度） を満足する大きさの隙間が設けられていることを
特徴とするセラミツクスクラウンピストン。 ２ 金属製部材の凹部側端部の一部に金属製部材
胴部直径より大径のフランジ部が形成されている
ことを特徴とする特許請求の範囲第１項記載のセ
ラミツクスクラウンピストン。 ３ セラミツクス製部材が部分安定化ジルコニ
ア、金属製部材が球状黒鉛鋳鉄であることを特徴
とする特許請求の範囲第１項記載のセラミツクス
クラウンピストン。 ４ セラミツクス製部材がピストンクラウンの一
部、金属製部材がピストン本体の一部であつて、
前記金属製部材の中心に設けられた凹部又は貫通
孔に、セラミツクス製ピストンクラウンの中央に
設けられた凸部を圧入してなるセラミツクスクラ
ウン・金属製部材結合体を金属製ピストンの頂部
に結合するセラミツクスクラウンピストンの製造
法において、セラミツクス製部材に設けた凸部の
直径を金属製部材に設ける凹部の内径より0.5％
〜５％大きくするとともに、該凹部に対し凸部を
金属製部材の焼なまし温度以下の温度で圧入し、
該金属製部材の凹部先端面とセラミツクス製ピス
トンクラウンの凸部底面の間に、室温において下
記の関係 （隙間の大きさ）＞（圧入部を構成する金属と
セラミツクスとの熱膨脹係数の差）×（圧入
距離）×（最高使用温度） を満足する大きさの隙間を設けることを特徴とす
るセラミツクスクラウンピストンの製造法。[Claims] 1. The ceramic member is part of the piston crown, the metal member is part of the piston body,
A ceramic piston crown/metal member assembly is joined to the top of the metal piston by press-fitting a protrusion provided at the center of the ceramic piston crown into a recess or through hole provided at the center of the metal member. In a ceramic crown piston, the following relationship exists at room temperature between the tip of the concave part of the metal member constituting the combined body and the bottom face of the convex part of the ceramic piston crown. A ceramic crown piston characterized by having a gap of a size that satisfies the following: (difference in coefficient of thermal expansion between 2. The ceramic crown piston according to claim 1, wherein a flange portion having a diameter larger than the diameter of the body of the metal member is formed at a part of the end of the metal member on the side of the recess. 3. The ceramic crown piston according to claim 1, wherein the ceramic member is partially stabilized zirconia and the metal member is spheroidal graphite cast iron. 4 The ceramic member is part of the piston crown, the metal member is part of the piston body,
A ceramic crown/metal member assembly is joined to the top of the metal piston by press-fitting a protrusion provided at the center of the ceramic piston crown into a recess or through hole provided at the center of the metal member. In the manufacturing method of ceramic crown pistons, the diameter of the convex part provided on the ceramic member is 0.5% of the inner diameter of the recessed part provided on the metal member.
~5% larger, and a convex part is press-fitted into the concave part at a temperature below the annealing temperature of the metal member,
The following relationship exists at room temperature between the tip of the concave part of the metal member and the bottom of the convex part of the ceramic piston crown (size of gap) > (difference in coefficient of thermal expansion between the metal and ceramics constituting the press-fit part) x A method of manufacturing a ceramic crown piston characterized by providing a gap of a size that satisfies (press-fit distance) x (maximum operating temperature).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27321389A JPH02211359A (en) | 1989-10-20 | 1989-10-20 | Ceramics crown piston and manufacture thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27321389A JPH02211359A (en) | 1989-10-20 | 1989-10-20 | Ceramics crown piston and manufacture thereof |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58158070A Division JPS6050204A (en) | 1983-08-31 | 1983-08-31 | Metal-ceramics bonded body and its manufacturing process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02211359A JPH02211359A (en) | 1990-08-22 |
| JPH0524346B2 true JPH0524346B2 (en) | 1993-04-07 |
Family
ID=17524677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27321389A Granted JPH02211359A (en) | 1989-10-20 | 1989-10-20 | Ceramics crown piston and manufacture thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02211359A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6018621A (en) * | 1983-07-11 | 1985-01-30 | Ishikawajima Harima Heavy Ind Co Ltd | Flexible shaft coupling device |
-
1989
- 1989-10-20 JP JP27321389A patent/JPH02211359A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6018621A (en) * | 1983-07-11 | 1985-01-30 | Ishikawajima Harima Heavy Ind Co Ltd | Flexible shaft coupling device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02211359A (en) | 1990-08-22 |
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