JPS6330962B2 - - Google Patents
Info
- Publication number
- JPS6330962B2 JPS6330962B2 JP58150543A JP15054383A JPS6330962B2 JP S6330962 B2 JPS6330962 B2 JP S6330962B2 JP 58150543 A JP58150543 A JP 58150543A JP 15054383 A JP15054383 A JP 15054383A JP S6330962 B2 JPS6330962 B2 JP S6330962B2
- Authority
- JP
- Japan
- Prior art keywords
- cam
- outer layer
- sintered
- inner layer
- shaft
- 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
Links
- 239000000843 powder Substances 0.000 claims description 25
- 238000005245 sintering Methods 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 14
- 239000000956 alloy Substances 0.000 claims description 8
- 238000005219 brazing Methods 0.000 claims description 8
- 239000007791 liquid phase Substances 0.000 claims description 8
- 230000008602 contraction Effects 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims 1
- 229910000881 Cu alloy Inorganic materials 0.000 claims 1
- 229910052802 copper Inorganic materials 0.000 claims 1
- 239000010949 copper Substances 0.000 claims 1
- 238000005192 partition Methods 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000005304 joining Methods 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 229910017518 Cu Zn Inorganic materials 0.000 description 1
- 229910017752 Cu-Zn Inorganic materials 0.000 description 1
- 229910002482 Cu–Ni Inorganic materials 0.000 description 1
- 229910017888 Cu—P Inorganic materials 0.000 description 1
- 229910017943 Cu—Zn Inorganic materials 0.000 description 1
- 229910007567 Zn-Ni Inorganic materials 0.000 description 1
- 229910007614 Zn—Ni Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical compound [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
Landscapes
- Valve-Gear Or Valve Arrangements (AREA)
- Powder Metallurgy (AREA)
Description
本発明は、内燃機関等のカムシヤフトにおい
て、シヤフト部とカム部とを別体とし、前記カム
部を焼結体から構成し、このカム部を前記シヤフ
ト部に嵌合固定してなるカムシヤフトに関するも
のである。
最近、内燃機関等のカムシヤフトにおいては、
耐摩耗性、耐高温性、加工性などの向上を目的と
して開発された焼結製のカムシヤフトが多用され
ている。このカムシヤフトは金属粉体を原料とす
る焼結体から構成したカム部を、例えば、クロム
モリブデン鋼により構成したシヤフト部の外周に
嵌合固定したものである。
上記構成のカムシヤフトにおけるシヤフト部に
対するカム部の固定は、(i)カム部をシヤフト部に
圧入して固定する方法、(ii)カム部をシヤフト部に
嵌合し、その嵌合接触部分をろう付けして固定す
る方法、(iii)カム部をシヤフト部に嵌合し、その嵌
合部分をかしめによつて固定する方法、(iv)機械的
にねじで固定する方法、(v)シヤフト部として鋼管
を用いる場合の固定で、シヤフト部のカム部に対
応した部分を膨出させ、この膨出部分をカム部内
周に圧接させて固定する、いわゆるバルジ加工に
より固定する方法などにより行なわれている。こ
れらの固定方法にあつては、いずれもカム部をシ
ヤフト部の外周に嵌合させることが必要であり、
そのため、嵌合前の各構成部品、特にカム部の嵌
合部の寸法精度が良好であることが要求され、そ
の結果、切削加工等の工数を要する寸法出しの工
程を必要としていた。
これに対し、焼結時に液相を生じる耐摩耗性焼
結合金材からカム部やジヤーナルを構成し、これ
によつてカム部やジヤーナルとシヤフト部とを拡
散接合によつて強固に固定させる方法も提案され
ている。しかし、この方法では、焼結に液相を生
じさせるため、焼結によるカム部やジヤーナルの
収縮量がきわめて大きくなり、しかもその収縮が
均一に起こらず、その結果、カム部やジヤーナル
のシヤフト部に対する位置決めに狂いが生じやす
かつた。さらに、焼結による収縮は、径方向ばか
りでなく軸方向においても大きく生じ不均一な収
縮となるため、カム部やジヤーナルの両端部に隙
間が発生する事を避けることができず、その結
果、接合強度も不充分になることがあり、信頼性
の点で満足できるものではなかつた。
本発明者らは、シヤフト部に対するカム部の固
定が強固で、カム部の寸法変化が少なく、工数を
かけることなく、組みつけのための位置決めを容
易、正確に行なえ、接合信頼性の高い焼結合金カ
ムシヤフトを得ることのできる製造方法を開発す
ることを目的に種々研究を重ねたところ、下記の
ような知見を得るに至つた。
すなわち、焼結前のカム部を外層と内層とに分
け、外層を耐摩耗性が高く、収縮量の大きい焼結
合金材から構成し、内層を収縮量の小さい焼結合
金材から構成し、このカム部をシヤフト部に組み
つけ、その後、焼結させれば、外層の大きな収縮
変化を内層が緩和し、寸法安定性が得られ、しか
もシヤフトとの締め代を適当な値にすることが可
能となることが判つた。さらに、上記外層の収縮
量は２％以上とし、上記内層の収縮量を２％未満
とすると、良好な接合が得られることが判明し
た。なお、この場合、カム部全体の内径部の収縮
量は、１％〜４％以内である事が好ましい。
本発明は上記知見に基づいてなされたものであ
る。すなわち、本発明は、カム部の圧粉成形体ま
たは仮焼結体を外層と内層とから構成し、外層を
焼結時に２％以上の収縮変化を生じる耐摩耗性焼
結材料から構成するとともに、内層を焼結時に２
％未満の収縮変化を生じる焼結材料から構成し、
このカム部の圧粉成形体または仮焼結体をシヤフ
ト部に組みつけ、その後、所定温度で加熱するこ
とにより、上記内外層の焼結と接合およびカム部
のその収縮によるシヤフト部への固定を同時に行
なつて焼結合金カムシヤフトを製造する方法であ
る。
以下、この発明を詳しく説明する。本発明によ
り製造されるカム部の外層は、例えば、Fe−
13Cr−1Mo−0.5Mn−0.5Nb−0.3P−2.6Cに示す
ように、比較的低い温度で液相を生じる成分を有
するとともに、焼結後高い耐摩耗性を発揮し、し
かも焼結時に２％以上の収縮変化を生じる耐摩耗
性焼結材料から構成される。
また、同カム部の内層は、例えば、Fe−3Ni−
1Cに示すように、耐摩耗性はそれ程高くはない
が、焼結時に２％未満の収縮変化を生じる焼結材
料から構成される。
第１図に示すように、上記カム部の圧粉成形体
１は、上記したように、外層２と内層３とから構
成されるが、この圧粉成形体１は、金型４の中央
部にコア・ロツド５を配置するとともに、金型４
の内周面とコア・ロツド５との間に上記外層２と
内層３との境界を形成する仕切曲板６を配置し、
この仕切曲板６と金型４の内周面との間に上記外
層２の投影形状を持つパンチを出入できるように
するとともに、上記仕切曲板６とコア・ロツド５
との間に上記内層３の投影形状を持つパンチを出
入できるようにした圧粉成形器７によつて成形す
る。上記圧粉成形器７において、仕切曲板６と金
型４の内周面との間に外層２を構成する混合粉末
を充填し、仕切曲板６とコア・ロツド５との間に
内層３を構成する混合粉末を充填した後、仕切曲
板６を取り去り、この状態で上下から圧縮するこ
とにより、第１図に示すような圧粉成形体１が形
成される。この圧粉成形体１において、外層２が
例えば、Fe−13Cr−1Mo−0.5Mn−0.5Nb−0.3P
−2.6Cから構成されるとともに、内層３が例え
ば、Fe−3Ni−1Cから構成された場合（後述、
実施例１）、最終圧縮前の外層２の見掛密度が2.8
ｇ／cm3となり、内層３の見掛密度が2.7ｇ／cm3と
なり、両粉末の見掛密度はほぼ同じ値となる。そ
して、両粉末の圧縮性（5ton／cm2の圧縮力で得ら
れる圧粉体の密度が6.2ｇ／cm3であつた）もほぼ
同じ特性であることから、5ton／cm2で最終圧縮し
た成形体の密度は、外層２、内層３ともほぼ同一
となる。また、上記構成上、圧縮成形後の外層２
と内層３の境界面では、両層の粉末同志が微小な
凹凸によつてからみ合つており、焼結時において
拡散がよりスムーズに行なわれることになり、外
層２−内層３間の接合強度がよく強く行なわれ
る。なお、第１図において、符号３ａは外層２と
内層３とをより強固に嵌合させるための凸部であ
り、３ｂ………は内層３とパイプシヤフト８（第
３図）とをより強固に嵌合させるための凸部であ
るが、上記したように接合は充分な強度で行なわ
れるので、強いて設ける必要はない。
上記のようにして構成した圧粉成形体１をその
ままか、または仮焼結した後、第３図に示すよう
な、パイプシヤフト（シヤフト部）８に嵌合す
る。この時の軸方向の位置合わせは、穴８ａに、
第４図に示すピン９を嵌め込むことより行なう。
また、ジヤーナル１０（第５図）も粉末焼結材
（例えば、Fe−3Ni−1C）で構成し、その軸方向
の位置合わせは、上記同様ピン９により行なう。
上記のようにしてカム部の圧粉成形体１または
その仮焼結体と、ジヤーナル１０をパイプシヤフ
ト８に組みつけ、1150℃で60分間、真空雰囲気中
で加熱する。この加熱により外層２と内層３とは
焼結、接合され、内層３とパイプシヤフト８とは
焼結時に生じる外層２および内層３の収縮により
強固に嵌合される。上記粉末組成の場合、外層２
は７％の収縮率を持ち、内層３は1.0％の収縮率
を持つため、外層２の収縮は、内層３により緩和
され、全体として1.8％という嵌合に適する収縮
率となる。
ここで、上記外層２と内層３との接合は、これ
らの境界面における焼結時の拡散と、外層２が内
層３より大きく収縮することにより行なわれるの
で、接合強度は、外層２と内層３の収縮率および
外層２の内径、内層３の外径の寸法に左右され、
体積比には左右されない。また、カム部（外層２
と内層３）のパイプシヤフト８への固定は、外層
２および内層３の収縮により行なわれるので、固
定強度は、外層２と内層３の収縮率および外層２
の内径、内層３の内外径の寸法に左右され、体積
比には左右されない。さらに、カム部は外層２と
内層３とが収縮することにより形成されるので、
カム部の寸法精度および位置ずれは外層２と内層
３の収縮率および外形寸法に左右され体積比には
左右されない。
このように、本発明では、収縮率の小さい内層
３が中間部分に存在し、この内層３が高い耐摩耗
性を持つ故に大きな外層２の収縮率を吸収、緩和
するクツシヨンの役目を果すため、カム部は均一
に収縮するとともに、その収縮による寸法のばら
つきも小さくなる。また、本発明では、本焼結体
に比べて寸法精度が良好な圧粉成形体または仮焼
結体を直接にパイプシヤフトに嵌合させ、その
後、本焼結するので、締め代のばらつきが小さく
なり、完成品（カムシヤフト）における寸法のば
らつきも、強度のばらつきも小さくすることがで
きる。
また、本発明において、カム部とパイプシヤフ
トとの間にろう材（例えば、Cu−20Ni）を介装
させ、その後、本焼結工程に移るようにすれば、
カム部をパイプシヤフトにカム部の収縮による固
定に加え、ろう材により接合固着することができ
るので、カム部のシヤフトへの固定をより強固に
することができる。
なお、本発明における内層の２％未満という収
縮率と、外層の２％以上という収縮率の数値限定
は、内層の収縮率を２％以上とし、外層の収縮率
を２％未満とすると、カム部とパイプシヤフトと
の間に隙間が生じたり、位置ずれが生じる等の不
都合が生じることが確認されたからである。ま
た、前述の如く、カム部全体の内径収縮量は１％
〜４％の範囲である事が好ましい。
また、上記したろう材は、その拡散によつて、
カム部とシヤフトとの接合強度をより強く、より
完全に、しかもより安定したものにする役目を果
しているものであり、その材料として、Cu−Ni
（20％）、Cu−Ｐ（8.4％）、Cu−Zn（40％）、Cu−
Sn（11％）、Cu−Ag−Zn（Ag；20％、Zn；35
％）、Cu−Ag−Zn（Ag；40％、Zn；20％）、Cu
−Fe（Fe；30％）、Cu−Zn−Ni（Ni；20％、Zn；
20％）などが考えられる。
さらに、本発明においては、外層の焼結におい
て、この外層に高い耐摩耗性を持たせるために、
かつ、嵌合接合に必要な高い収縮率を得るために
は、液相焼結を行なわせることが最も確実で簡単
な方法である。この液相焼結によつて、外層から
発生した液相が内層に到達し、内層の構成粒子と
の間に拡散接合を起こすので、内外層間の接合強
度をより向上させることができる。
以上説明したように、本発明は、カム部の圧粉
成形体または仮焼結体を外層と内層とから構成
し、外層を焼結時に２％以上の収縮変化を生じる
耐摩耗性焼結材料から構成するとともに、内層を
焼結時に２％未満の収縮変化を生じる焼結材料か
ら構成し、このカム部の圧粉成形体または仮焼結
体をシヤフト部に組みつけ、その後、所定温度で
加熱することにより、上記内外層の焼結と接合お
よびカム部のその収縮によるシヤフト部への固定
を同時に行なうものなので、シヤフト部に対する
カム部の固定が強固で、カム部の寸法変化が少な
く、工数をかけることなく組みつけのための位置
決めを容易、正確に行なえ、接合信頼性の高い焼
結合金カムシヤフトを得ることができる。
なお、上記本発明の説明において、カム部の圧
粉成形体または仮焼結体を内層と外層とが一体的
に圧縮成形されたものとしたが、内層と外層とを
別々に成形し、これらをカムシヤフトの組みつけ
時に組み合わせるようにしてもよい。さらに形状
についても説明では位置合わせを設けたが、この
限りではない。
次に実施例によつて本発明をさらに詳細に説明
する。
実施例
次表の１〜４に示すような構成の外層および内
層粉末材料を用い、上記本発明の方法に基づき、
圧粉成形体をつくり、これをクロムモリブデン鋼
製のパイプシヤフトに組みつけ、上記したよう
に、1150℃で60分間、真空雰囲気中で加熱した。
なお、実施例３においては、ろう材（Cu−20Ni）
をカム部とパイプシヤフトとの間に介装させた。
また、実施例５においては、上記実施例４と同
構成材料により950℃で仮焼結した仮焼結体を構
成し、これをパイプシヤフトに組みつけるように
した。
上記実施例１〜５に対し、比較例として、同表
〜にそれぞれ示すような構成の粉末で、内外
層の収縮率が共に２％未満のカム部の圧粉成形体
と、外層の収縮率が２％未満でかつ内層の収縮率
が２％以上のカム部の圧粉成形体と、内外層の収
縮率が共に２％以上のカム部の圧粉成形体とを形
成し、後は実施例１〜４と同様の方法によりカム
シヤフトを製造した。
上記各実施例１〜５および比較例〜の接合
状態および位置ずれの外観チエツクを行なつたと
ころ、同表に示すように、比較例、では若干
の隙間が発生するとともに位置ずれが生じ、比較
例では隙間が発生したのに対し、実施例１〜５
では接合状態は良好であり、位置ずれの発生も皆
無であつた。特に、ろう材を使つた実施例３にお
ける接合は強固であつた。
The present invention relates to a camshaft for an internal combustion engine, etc., in which a shaft part and a cam part are separated, the cam part is made of a sintered body, and the cam part is fitted and fixed to the shaft part. It is. Recently, in camshafts for internal combustion engines,
Sintered camshafts, which were developed to improve wear resistance, high temperature resistance, and workability, are widely used. This camshaft has a cam portion made of a sintered body made of metal powder, which is fitted and fixed to the outer periphery of a shaft portion made of, for example, chromium molybdenum steel. In the camshaft having the above configuration, the cam part can be fixed to the shaft part by (i) press-fitting the cam part into the shaft part and fixing it; (ii) fitting the cam part into the shaft part and brazing the fitting contact part. (iii) method of fitting the cam part to the shaft part and fixing the fitted part by caulking, (iv) method of fixing mechanically with screws, (v) method of fixing the shaft part When a steel pipe is used as a cam, this is done by bulging a portion of the shaft that corresponds to the cam, and fixing by pressing this bulge against the inner circumference of the cam. There is. In all of these fixing methods, it is necessary to fit the cam part to the outer periphery of the shaft part,
Therefore, each component, especially the fitting portion of the cam portion, is required to have good dimensional accuracy before fitting, and as a result, a dimensional process such as cutting that requires many man-hours is required. On the other hand, there is a method in which the cam part and journal are constructed from a wear-resistant sintered alloy material that generates a liquid phase during sintering, and the cam part and journal are firmly fixed to the shaft part by diffusion bonding. has also been proposed. However, since this method generates a liquid phase during sintering, the amount of shrinkage of the cam part and journal due to sintering becomes extremely large, and the shrinkage does not occur uniformly, resulting in the shrinkage of the cam part and shaft part of the journal. Misalignment was likely to occur in positioning. Furthermore, the shrinkage due to sintering occurs not only in the radial direction but also in the axial direction, resulting in non-uniform shrinkage, so it is impossible to avoid the formation of gaps at both ends of the cam part and journal. The bonding strength may also be insufficient, and the reliability is not satisfactory. The inventors of the present invention have developed a sintering system that has a strong fixation of the cam part to the shaft part, small dimensional changes in the cam part, easy and accurate positioning for assembly without requiring any man-hours, and a highly reliable joint. As a result of various research aimed at developing a manufacturing method capable of producing a bonded metal camshaft, the following findings were obtained. That is, the cam part before sintering is divided into an outer layer and an inner layer, the outer layer is made of a sintered alloy material with high wear resistance and a large amount of shrinkage, and the inner layer is made of a sintered alloy material with a small amount of shrinkage. If this cam part is assembled to the shaft part and then sintered, the inner layer will absorb the large shrinkage change of the outer layer, providing dimensional stability and making it possible to set the interference with the shaft to an appropriate value. It turned out to be possible. Furthermore, it has been found that good bonding can be obtained when the amount of shrinkage of the outer layer is 2% or more and the amount of shrinkage of the inner layer is less than 2%. In this case, the amount of contraction of the inner diameter portion of the entire cam portion is preferably within 1% to 4%. The present invention has been made based on the above findings. That is, in the present invention, the powder compact or temporary sintered body of the cam part is composed of an outer layer and an inner layer, and the outer layer is composed of a wear-resistant sintered material that undergoes a shrinkage change of 2% or more during sintering. , 2 when sintering the inner layer
Constructed from a sintered material that produces a shrinkage change of less than %,
The powder compact or temporary sintered body of the cam part is assembled to the shaft part, and then heated at a predetermined temperature to sinter and bond the inner and outer layers, and the cam part is fixed to the shaft part by shrinking. This is a method of manufacturing a sintered alloy camshaft by simultaneously performing the following steps. This invention will be explained in detail below. The outer layer of the cam part manufactured according to the present invention is, for example, Fe-
As shown in 13Cr−1Mo−0.5Mn−0.5Nb−0.3P−2.6C, it has components that form a liquid phase at relatively low temperatures, exhibits high wear resistance after sintering, and Constructed from a wear-resistant sintered material that exhibits a shrinkage change of more than %. In addition, the inner layer of the cam part is, for example, Fe-3Ni-
As shown in 1C, it is composed of a sintered material that does not have very high wear resistance but exhibits a shrinkage change of less than 2% upon sintering. As shown in FIG. 1, the powder compact 1 of the cam portion is composed of the outer layer 2 and the inner layer 3 as described above, and the powder compact 1 is formed at the center of the mold 4. At the same time, place the core rod 5 in the mold 4.
A partition curved plate 6 forming a boundary between the outer layer 2 and the inner layer 3 is disposed between the inner peripheral surface of the core rod 5 and the core rod 5,
A punch having the projected shape of the outer layer 2 can be moved in and out between the partition curved plate 6 and the inner circumferential surface of the mold 4, and the partition curved plate 6 and the core rod 5 can be moved in and out.
A powder compacting machine 7 is used between which a punch having the projected shape of the inner layer 3 can be moved in and out. In the compacting machine 7, a mixed powder constituting the outer layer 2 is filled between the partition curved plate 6 and the inner peripheral surface of the mold 4, and an inner layer 3 is filled between the partition curved plate 6 and the core rod 5. After filling the mixed powder constituting the powder, the partition curved plate 6 is removed, and the powder compact 1 as shown in FIG. 1 is formed by compressing from above and below in this state. In this powder compact 1, the outer layer 2 is, for example, Fe-13Cr-1Mo-0.5Mn-0.5Nb-0.3P
-2.6C, and the inner layer 3 is made of, for example, Fe-3Ni-1C (described later,
Example 1), the apparent density of the outer layer 2 before final compression is 2.8
g/cm 3 , the apparent density of the inner layer 3 is 2.7 g/cm 3 , and the apparent densities of both powders are approximately the same value. Since the compressibility of both powders was almost the same (the density of the green compact obtained with a compression force of 5 ton/cm 2 was 6.2 g/cm 3 ), the final compression was carried out at 5 ton/cm 2. The density of the molded body is almost the same for both the outer layer 2 and the inner layer 3. In addition, due to the above structure, the outer layer 2 after compression molding
At the interface between the outer layer 2 and the inner layer 3, the powders of both layers are intertwined with each other due to minute irregularities, which allows for smoother diffusion during sintering, increasing the bonding strength between the outer layer 2 and the inner layer 3. It is done well and strongly. In FIG. 1, reference numeral 3a is a convex portion for more firmly fitting the outer layer 2 and inner layer 3, and 3b is a convex portion for more firmly fitting the inner layer 3 and the pipe shaft 8 (see FIG. 3). Although this is a convex portion for fitting, there is no need to forcibly provide it because the joining is performed with sufficient strength as described above. The powder compact 1 constructed as described above is fitted into a pipe shaft (shaft portion) 8 as shown in FIG. 3, either as is or after being pre-sintered. At this time, the alignment in the axial direction is as follows:
This is done by fitting the pin 9 shown in FIG.
Further, the journal 10 (FIG. 5) is also made of a powder sintered material (for example, Fe-3Ni-1C), and its axial alignment is performed by the pin 9 as described above. As described above, the powder compact 1 of the cam portion or its temporary sintered body and the journal 10 are assembled on the pipe shaft 8 and heated at 1150° C. for 60 minutes in a vacuum atmosphere. By this heating, the outer layer 2 and the inner layer 3 are sintered and joined, and the inner layer 3 and the pipe shaft 8 are firmly fitted together due to the shrinkage of the outer layer 2 and the inner layer 3 that occurs during sintering. In the case of the above powder composition, the outer layer 2
has a shrinkage rate of 7%, and the inner layer 3 has a shrinkage rate of 1.0%, so the shrinkage of the outer layer 2 is alleviated by the inner layer 3, resulting in an overall shrinkage rate of 1.8% suitable for fitting. Here, the bonding between the outer layer 2 and the inner layer 3 is achieved by diffusion during sintering at their interface and by the outer layer 2 contracting more than the inner layer 3, so the bonding strength is depends on the shrinkage rate and the dimensions of the inner diameter of the outer layer 2 and the outer diameter of the inner layer 3,
It is not affected by volume ratio. In addition, the cam part (outer layer 2
and inner layer 3) are fixed to the pipe shaft 8 by shrinking the outer layer 2 and inner layer 3, so the fixing strength depends on the shrinkage rate of outer layer 2 and inner layer 3 and the outer layer 2.
It depends on the inner diameter of the inner layer 3 and the inner and outer diameters of the inner layer 3, but is not affected by the volume ratio. Furthermore, since the cam portion is formed by contraction of the outer layer 2 and the inner layer 3,
The dimensional accuracy and positional deviation of the cam portion depend on the shrinkage rate and external dimensions of the outer layer 2 and inner layer 3, and are not affected by the volume ratio. In this way, in the present invention, the inner layer 3 with a small shrinkage rate is present in the middle part, and since this inner layer 3 has high abrasion resistance, it plays the role of a cushion that absorbs and alleviates the large shrinkage rate of the outer layer 2. The cam portion contracts uniformly, and variations in dimensions due to the contraction are reduced. In addition, in the present invention, a powder compact or a temporary sintered body, which has better dimensional accuracy than the actual sintered body, is directly fitted onto the pipe shaft and then subjected to final sintering, so that variations in tightness are reduced. This makes it possible to reduce dimensional variations and strength variations in the finished product (camshaft). Furthermore, in the present invention, if a brazing material (for example, Cu-20Ni) is interposed between the cam part and the pipe shaft, and then the main sintering process is performed,
In addition to being fixed to the pipe shaft by contraction of the cam part, the cam part can be bonded and fixed to the pipe shaft using a brazing material, so that the cam part can be more firmly fixed to the shaft. In addition, in the present invention, the numerical limitation of the shrinkage rate of the inner layer to less than 2% and the shrinkage rate of the outer layer to 2% or more means that if the shrinkage rate of the inner layer is 2% or more and the shrinkage rate of the outer layer is less than 2%, the cam This is because it has been confirmed that problems such as a gap or misalignment occur between the pipe shaft and the pipe shaft. In addition, as mentioned above, the inner diameter contraction amount of the entire cam part is 1%.
The range is preferably 4%. In addition, the above-mentioned brazing filler metal, due to its diffusion,
It plays the role of making the bonding strength between the cam part and the shaft stronger, more complete, and more stable, and Cu-Ni is used as the material for this purpose.
(20%), Cu-P (8.4%), Cu-Zn (40%), Cu-
Sn (11%), Cu-Ag-Zn (Ag; 20%, Zn; 35
%), Cu−Ag−Zn (Ag; 40%, Zn; 20%), Cu
−Fe (Fe; 30%), Cu−Zn−Ni (Ni; 20%, Zn;
20%). Furthermore, in the present invention, in sintering the outer layer, in order to give this outer layer high wear resistance,
In addition, in order to obtain the high shrinkage rate necessary for fitting and joining, liquid phase sintering is the most reliable and simplest method. By this liquid phase sintering, the liquid phase generated from the outer layer reaches the inner layer and causes diffusion bonding with the constituent particles of the inner layer, so that the bonding strength between the inner and outer layers can be further improved. As explained above, the present invention consists of a powder compact or a temporary sintered body of the cam part consisting of an outer layer and an inner layer, and the outer layer is made of a wear-resistant sintered material that undergoes a shrinkage change of 2% or more during sintering. The inner layer is made of a sintered material that undergoes a shrinkage change of less than 2% during sintering, and the compacted or temporarily sintered body of the cam part is assembled to the shaft part, and then heated at a predetermined temperature. By heating, the inner and outer layers are sintered and bonded, and the cam part is fixed to the shaft part by contraction, so the cam part is firmly fixed to the shaft part, and there is little dimensional change in the cam part. It is possible to obtain a sintered alloy camshaft that allows easy and accurate positioning for assembly without requiring any man-hours and has high bonding reliability. In the above description of the present invention, the compacted body or temporary sintered body of the cam part was assumed to be one in which the inner layer and the outer layer were integrally compression-molded, but the inner layer and the outer layer were molded separately, and these may be combined when assembling the camshaft. Furthermore, although positioning is provided in the description regarding the shape, this is not limited to this. Next, the present invention will be explained in more detail with reference to Examples. Example Using the outer layer and inner layer powder materials having the configurations shown in Tables 1 to 4 below, based on the method of the present invention,
A powder compact was produced, assembled onto a chrome-molybdenum steel pipe shaft, and heated in a vacuum atmosphere at 1150°C for 60 minutes as described above.
In addition, in Example 3, the brazing material (Cu-20Ni)
was interposed between the cam part and the pipe shaft. Further, in Example 5, a pre-sintered body was constructed by pre-sintering at 950° C. using the same constituent materials as in Example 4, and this was assembled into a pipe shaft. In contrast to Examples 1 to 5 above, as a comparative example, a powder compact of a cam part with a shrinkage rate of both the inner and outer layers of less than 2% and a shrinkage rate of the outer layer were prepared using powders having the compositions shown in the same table. A compacted body of the cam part in which the shrinkage rate of the inner layer is less than 2% and a shrinkage rate of 2% or more in the inner layer, and a compacted body of the cam part in which the shrinkage rate of the inner and outer layers are both 2% or more are formed, and the rest is carried out. Camshafts were manufactured in the same manner as in Examples 1-4. When we checked the appearance of the joint states and positional deviations of each of Examples 1 to 5 and Comparative Examples ~, we found that, as shown in the table, slight gaps and positional deviations occurred in the Comparative Examples. In contrast to the example in which a gap occurred, Examples 1 to 5
The bonding condition was good, and no misalignment occurred. In particular, the bonding in Example 3 using the brazing material was strong.
【表】【table】
第１図ないし第５図は、本発明を説明するため
のもので、第１図はカム部の圧粉成形体の斜視
図、第２図は圧粉成形器の斜視図、第３図はパイ
プシヤフトの斜視図、第４図は位置決め用のピン
の斜視図、第５図はジヤーナルの斜視図である。
１……カム部の圧粉成形体、２……外層、３…
…内層、４……金型、５……コア・ロツド、６…
…仕切曲板、８……パイプシヤフト（シヤフト
部）、９……ピン、１０……ジヤーナル。
Figures 1 to 5 are for explaining the present invention. Figure 1 is a perspective view of the compacted product of the cam portion, Figure 2 is a perspective view of the compacting machine, and Figure 3 is a perspective view of the compacted product of the cam part. FIG. 4 is a perspective view of the pipe shaft, FIG. 4 is a perspective view of the positioning pin, and FIG. 5 is a perspective view of the journal. 1...Powder compact of cam part, 2...Outer layer, 3...
...Inner layer, 4...Mold, 5...Core rod, 6...
...Partition curved plate, 8...Pipe shaft (shaft part), 9...Pin, 10...Journal.
Claims (1)
固定した焼結合金カムシヤフトを製造する方法に
おいて、 前記カム部の圧粉成形体または仮焼結体を外周
にカム面を持つ外層と前記シヤフト部に嵌着する
内層とから構成し、 前記外層を焼結時に２％以上の収縮変化を生じ
る耐摩耗性焼結材料から構成するとともに、前記
内層を焼結時に２％未満の収縮変化を生じる焼結
材料から構成し、 前記カム部の圧粉成形体または仮焼結体を前記
シヤフト部に組みつけ、その後、所定温度で加熱
することにより、前記内外層の焼結と接合および
前記カム部のその収縮によるシヤフト部への固定
を同時に行なうことを特徴とする焼結合金カムシ
ヤフトの製造方法。 ２ カム部をシヤフト部に組みつける時にこれら
カム部とシヤフト部との間に銅または銅合金から
なるろう材を介装させ、所定温度で加熱すること
により、前記カム部を前記シヤフト部に前記カム
部の収縮による固定に加え、前記ろう材により接
合固着することを特徴とする特許請求の範囲第１
項に記載の焼結合金カムシヤフトの製造方法。 ３ カム部をシヤフト部に組みつけた後の加熱に
おいて、外層を構成する耐摩耗性焼結材料に液相
が生じ、この液相により、少なくとも内層と外層
を接合固着することを特徴とする特許請求の範囲
第１項または第２項に記載の焼結合金カムシヤフ
トの製造方法。[Scope of Claims] 1. A method for manufacturing a sintered alloy camshaft in which a cam part made of a sintered material is fitted and fixed on the outer periphery of the shaft part, comprising: applying a powder compact or a temporary sintered body of the cam part to the outer periphery It is composed of an outer layer having a cam surface and an inner layer that fits into the shaft part, the outer layer is made of a wear-resistant sintered material that undergoes a shrinkage change of 2% or more during sintering, and the inner layer is made of a wear-resistant sintered material that undergoes a shrinkage change of 2% or more during sintering. It is made of a sintered material that exhibits a shrinkage change of less than 2%, and the compacted powder body or temporary sintered body of the cam part is assembled to the shaft part, and then heated at a predetermined temperature, thereby forming the inner and outer layers. A method for manufacturing a sintered alloy camshaft, characterized in that sintering, bonding, and fixing the cam portion to the shaft portion by shrinking the cam portion are performed simultaneously. 2. When assembling the cam portion to the shaft portion, a brazing material made of copper or copper alloy is interposed between the cam portion and the shaft portion and heated at a predetermined temperature, thereby attaching the cam portion to the shaft portion. Claim 1, characterized in that in addition to fixation by contraction of the cam part, bonding and fixation is performed by the brazing material.
A method for manufacturing a sintered alloy camshaft as described in 2. 3. A patent characterized in that a liquid phase is generated in the wear-resistant sintered material constituting the outer layer during heating after the cam part is assembled to the shaft part, and this liquid phase bonds and fixes at least the inner layer and the outer layer. A method for manufacturing a sintered metal camshaft according to claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15054383A JPS6043405A (en) | 1983-08-18 | 1983-08-18 | Production of cam shaft consisting of sintered alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15054383A JPS6043405A (en) | 1983-08-18 | 1983-08-18 | Production of cam shaft consisting of sintered alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6043405A JPS6043405A (en) | 1985-03-08 |
| JPS6330962B2 true JPS6330962B2 (en) | 1988-06-21 |
Family
ID=15499164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15054383A Granted JPS6043405A (en) | 1983-08-18 | 1983-08-18 | Production of cam shaft consisting of sintered alloy |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6043405A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104708006A (en) * | 2013-12-11 | 2015-06-17 | 北京有色金属研究总院 | Powder metallurgy compound cam and manufacturing method thereof |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0610286B2 (en) * | 1988-03-17 | 1994-02-09 | 日本ピストンリング株式会社 | Camshaft manufacturing method |
| US8510942B2 (en) * | 2008-10-08 | 2013-08-20 | GM Global Technology Operations LLC | Camshaft lobe and method of making same |
| US8951466B2 (en) * | 2009-01-26 | 2015-02-10 | GM Global Technology Operations LLC | Method of making component shapes having non-round exterior shapes |
| CN103032120B (en) * | 2011-09-29 | 2015-08-26 | 北京有色金属研究总院 | A kind of powder metallurgy multiple mounted cam sheet |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5841211A (en) * | 1981-09-04 | 1983-03-10 | Nippon Piston Ring Co Ltd | Cam shaft |
-
1983
- 1983-08-18 JP JP15054383A patent/JPS6043405A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5841211A (en) * | 1981-09-04 | 1983-03-10 | Nippon Piston Ring Co Ltd | Cam shaft |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104708006A (en) * | 2013-12-11 | 2015-06-17 | 北京有色金属研究总院 | Powder metallurgy compound cam and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6043405A (en) | 1985-03-08 |
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