JP3292500B2 - FCD piston for internal combustion engine - Google Patents

FCD piston for internal combustion engine

Info

Publication number
JP3292500B2
JP3292500B2 JP12146692A JP12146692A JP3292500B2 JP 3292500 B2 JP3292500 B2 JP 3292500B2 JP 12146692 A JP12146692 A JP 12146692A JP 12146692 A JP12146692 A JP 12146692A JP 3292500 B2 JP3292500 B2 JP 3292500B2
Authority
JP
Japan
Prior art keywords
piston
fcd
graphite
graphite particle
internal combustion
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 - Fee Related
Application number
JP12146692A
Other languages
Japanese (ja)
Other versions
JPH05296348A (en
Inventor
健治 三原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Priority to JP12146692A priority Critical patent/JP3292500B2/en
Publication of JPH05296348A publication Critical patent/JPH05296348A/en
Application granted granted Critical
Publication of JP3292500B2 publication Critical patent/JP3292500B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Pistons, Piston Rings, And Cylinders (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は、内燃機関用FCDピス
トンに関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FCD piston for an internal combustion engine.

【0002】[0002]

【従来の技術】従来、内燃機関用ピストンは、ピストン
に要求される材料特性である、高温に耐えしかも熱伝導
が良いこと、軽量であること、熱膨張係数が小さいこ
と、耐久性、耐摩耗性が良いことなどから、主にアルミ
合金が使用されている。
2. Description of the Related Art Conventionally, pistons for internal combustion engines have required material properties required for pistons: high temperature resistance and good heat conduction, light weight, low thermal expansion coefficient, durability and wear resistance. Aluminum alloys are mainly used because of their good properties.

【0003】ところで近時、高出力化、低騒音化、低燃
費化の要求に対応するため、耐熱性にすぐれ、熱膨張が
少なくシリンダライナとピストンの隙間が小さくでき、
強度が高いためピストントップリングをピストン頭部に
近づけて組み込むことができ(ハイトップリング)、燃
焼室ムダ容積を小さくできるなどの理由により、FCD
(球状黒鉛鋳鉄)がピストン用材料として使用されつつ
ある。
In recent years, in order to meet demands for higher output, lower noise, and lower fuel consumption, heat resistance is excellent, thermal expansion is small, and the gap between the cylinder liner and the piston can be reduced.
Due to the high strength, the piston top ring can be installed close to the piston head (high top ring), and the FCD can be reduced because the combustion chamber waste volume can be reduced.
(Spheroidal graphite cast iron) is being used as a material for pistons.

【0004】[0004]

【発明が解決しようとする課題】しかしながらFCD
は、強度上げる、熱伝導度悪化る不都合があ
る。従って、かかる特性に留意したFCDピストンでな
いとの耐久性に影響する。
SUMMARY OF THE INVENTION However , FCD
Is, increasing the strength, there is a disadvantage thermal conductivity you worse. Therefore, it is not possible to use an FCD piston that takes such characteristics into account.
It intended to affect the durability of it.

【0005】[0005]

【課題を解決するための手段】上記特性に鑑み、本発明
に係わる内燃機関用FCDピストンは、材料がFCDで
ある内燃機関用ピストンにおいて、前記FCDは、黒鉛
粒径が極小径側から大径方向へと大きくなるにつれ疲労
強度がほぼリニアに極大側から小方向へと減少し、かつ
熱伝導度が悪い第1性向と、黒鉛粒径が極大径側から小
径方向へと小さくなるにつれても疲労強度が極小側で殆
ど変化せず極小であるが、熱伝導度が良い第2性向と、
前記第1、第2性向との両終端に両端を接続して前記両
性向が緩やかに変化する第3性向とを発揮するFCDで
あり、ピストン頭部1は、第2性向を発揮する範囲の
鉛粒径の黒鉛備え、かつピストンピンボス部2は、第
1性向を発揮する範囲の黒鉛粒径の黒鉛備えていた
成とした。
SUMMARY OF THE INVENTION In view of the above characteristics, the FCD piston for an internal combustion engine according to the present invention has a material of FCD.
In one piston for an internal combustion engine, the FCD is graphite.
Fatigue as the grain size increases from the extremely small diameter side to the large diameter direction
The intensity decreases almost linearly from the maximum side to the small side, and
The first tendency with poor thermal conductivity and the graphite particle size is smaller from the maximum diameter side
As the diameter decreases in the radial direction, the fatigue strength is
The second tendency, which is minimal without change, but has good thermal conductivity,
Both ends are connected to both ends of the first and second propensities.
FCD with a third tendency, where the tendency changes slowly
There, the piston head 1 is provided with a graphite black <br/> Namaritsubu径range to exert second tendency, and the piston pin boss portion 2, the
The structure was provided with graphite having a graphite particle diameter in a range exhibiting one tendency .

【0006】[0006]

【作用】上記構成によれば、ピストン頭部1の熱伝導度
が他の部位よりも向上し、ピストンピンボス部2の強度
が他の部位よりも向上するため、該ピストンの耐久性が
向上する。
According to the above construction, the thermal conductivity of the piston head 1 is improved as compared with other portions, and the strength of the piston pin boss portion 2 is improved as compared with other portions, so that the durability of the piston is improved. You.

【0007】[0007]

【実施例】本発明の実施例について説明する。図1はピ
ストンの部分断面平面図である。図2はパーライト系ダ
クタイル鋳鉄の黒鉛粒径の大きさと疲労限度との関係を
示すグラフであり、横軸は黒鉛粒径の大きさ(μ)を示
し、縦軸は疲労限度(kg/mm2)を示しており、同
グラフから黒鉛粒径が小さくなると疲労限度が向上する
ことがわかる。さらに、熱伝導度は、黒鉛粒径の大きさ
と反比例しており、黒鉛粒径が大きくなると熱伝導度は
良くなる。
An embodiment of the present invention will be described. FIG. 1 is a partial sectional plan view of a piston. FIG. 2 is a graph showing the relationship between the graphite particle size and the fatigue limit of the pearlite-based ductile cast iron. The horizontal axis shows the graphite particle size (μ), and the vertical axis shows the fatigue limit (kg / mm 2). It can be seen from the graph that the smaller the graphite particle size, the higher the fatigue limit. Further, the thermal conductivity is inversely proportional to the size of the graphite particle size, and the larger the graphite particle size, the better the thermal conductivity.

【0008】本実施例は、図1のピストン頭部1は、図
2のbで示す黒鉛粒径が大きい組織とし、図1のピスト
ンピンボス部2は、図2のaで示す黒鉛粒径が小さい組
織としたものである。
In this embodiment, the piston head 1 shown in FIG. 1 has a structure having a large graphite particle size shown in FIG. 2B, and the piston pin boss portion 2 shown in FIG. 1 has a graphite particle size shown in FIG. It is a small organization.

【0009】上記実施例によれば、エンジン稼働時に燃
焼ガスによって、最も熱影響を受けるピストン頭部1は
熱伝導度を向上せしめ、最も力を受けるピストンピンボ
ス部2は強度を向上せしめる。この結果、ピストンの各
々の部位で熱伝導度をより必要とされる部位では、熱伝
導度が向上され、強度をより必要とされる部位では、強
度が向上されるため、ピストンの耐久性が向上すること
になる。尚、黒鉛粒径を大きくしたり小さくする制御
は、鋳造時の冷却条件の制御又は熱処理条件の制御でも
よく、適宜自在である。
According to the above-described embodiment, the piston head 1 which is most affected by the combustion gas during operation of the engine improves the thermal conductivity, and the piston pin boss portion 2 which receives the most force improves the strength. As a result, the thermal conductivity is improved in the parts where the thermal conductivity is more required in each part of the piston, and the strength is improved in the parts where the strength is more required, so that the durability of the piston is improved. Will be improved. The control for increasing or decreasing the graphite particle size may be control of cooling conditions during casting or control of heat treatment conditions, and may be appropriately performed.

【0010】[0010]

【発明の効果】以上説明したように、本発明に係わる内
燃機関用FCDピストンは、エンジン稼働時に燃焼ガス
によって、最も熱影響を受けるピストン頭部は、黒鉛粒
径を大きい組織にして熱伝導度を向上させ、最も力を受
けるピストンピンボス部は、黒鉛粒径を小さい組織にし
て強度を向上させたので、熱伝導度と強度がバランスよ
く配合されてピストンの耐久性を向上させることができ
る。
As described above, in the FCD piston for an internal combustion engine according to the present invention, the piston head which is most thermally affected by the combustion gas during operation of the engine has a structure in which the graphite particle size is large and the thermal conductivity is large. the improved, most piston pin boss portion for receiving a force, so improved the strength and the graphite grain diameter smaller tissue, can heat conductivity and strength improves the durability of the balance may be formulated piston
You.

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

【図1】ピストンの部分断面平面図である。FIG. 1 is a partial cross-sectional plan view of a piston.

【図2】パーライト系ダクタイル鋳鉄の黒鉛粒径の大き
さと疲労限度との関係を示すグラフである。
FIG. 2 is a graph showing the relationship between the graphite particle size of pearlitic ductile cast iron and the fatigue limit.

【符号の説明】[Explanation of symbols]

1 ピストン頭部 2 ピストンピンボス部 1 Piston head 2 Piston pin boss

フロントページの続き (56)参考文献 特開 平1−131374(JP,A) 特開 昭62−118161(JP,A) 特開 平1−56852(JP,A) 特開 昭55−153838(JP,A) 特開 昭64−74360(JP,A) 特開 平3−33458(JP,A) 実開 昭63−93442(JP,U) 実開 昭63−28957(JP,U) 実開 平3−87848(JP,U) (58)調査した分野(Int.Cl.7,DB名) F16J 1/01 F02F 3/00 Continuation of front page (56) References JP-A-1-131374 (JP, A) JP-A-62-118161 (JP, A) JP-A-1-56852 (JP, A) JP-A-55-153838 (JP) , A) JP-A-64-74360 (JP, A) JP-A-3-33458 (JP, A) JP-A-63-93442 (JP, U) JP-A-63-28957 (JP, U) 3-87848 (JP, U) (58) Field surveyed (Int. Cl. 7 , DB name) F16J 1/01 F02F 3/00

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 材料がFCDである内燃機関用ピストン
において、前記FCDは、 黒鉛粒径が極小径側から大径方向へと大きくなるにつれ
疲労強度がほぼリニアに極大側から小方向へと減少し、
かつ熱伝導度が悪い第1性向(a)と、 黒鉛粒径が極大径側から小径方向へと小さくなるにつれ
ても疲労強度が極小側で殆ど変化せず極小であるが、熱
伝導度が良い第2性向(b)と、 前記第1、第2性向(a)(b)との両終端に両端を接続して
前記両性向(a)(b)が緩やかに変化する第3性向とを発揮
するFCDであり、 ピストン頭部1は、第2性向(b)を発揮する範囲の黒鉛
粒径の黒鉛備え、かつピストンピンボス部2は、第1
性向(a)を発揮する範囲の黒鉛粒径の黒鉛備えている
ことを特徴とする内燃機関用FCDピストン。
1. A piston for an internal combustion engine in which the material is FCD, wherein the FCD increases in size as the graphite particle size increases from the extremely small diameter side to the large diameter direction.
Fatigue strength decreases almost linearly from the maximum side to the small direction,
With the first tendency (a) and poor thermal conductivity, as the graphite particle diameter decreases from the maximum diameter side to the small diameter direction,
Even though the fatigue strength is minimal with little change on the minimal side,
Both ends are connected to both ends of the second tendency (b) having good conductivity and the first and second tendencies (a) and (b).
Demonstrates the third propensity in which both propensities (a) and (b) change slowly
The piston head 1 is provided with graphite having a graphite particle diameter in a range exhibiting the second tendency (b) , and the piston pin boss portion 2 is provided with a first pin .
FCD piston for an internal combustion engine according to claim <br/> that it comprises a range of graphite of the graphite particle size exhibit propensity (a).
JP12146692A 1992-04-15 1992-04-15 FCD piston for internal combustion engine Expired - Fee Related JP3292500B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12146692A JP3292500B2 (en) 1992-04-15 1992-04-15 FCD piston for internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12146692A JP3292500B2 (en) 1992-04-15 1992-04-15 FCD piston for internal combustion engine

Publications (2)

Publication Number Publication Date
JPH05296348A JPH05296348A (en) 1993-11-09
JP3292500B2 true JP3292500B2 (en) 2002-06-17

Family

ID=14811846

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12146692A Expired - Fee Related JP3292500B2 (en) 1992-04-15 1992-04-15 FCD piston for internal combustion engine

Country Status (1)

Country Link
JP (1) JP3292500B2 (en)

Also Published As

Publication number Publication date
JPH05296348A (en) 1993-11-09

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