JPH0333458A - Powder injection molded piston - Google Patents

Powder injection molded piston

Info

Publication number
JPH0333458A
JPH0333458A JP16817889A JP16817889A JPH0333458A JP H0333458 A JPH0333458 A JP H0333458A JP 16817889 A JP16817889 A JP 16817889A JP 16817889 A JP16817889 A JP 16817889A JP H0333458 A JPH0333458 A JP H0333458A
Authority
JP
Japan
Prior art keywords
alloy
skirt
piston
injection molding
constitution
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.)
Pending
Application number
JP16817889A
Other languages
Japanese (ja)
Inventor
Hideki Miyamoto
秀樹 宮本
Fujito Uotani
魚谷　不二人
Yasufumi Tsunetomi
常富　容史
Kazuhiro Shiraishi
白石　一洋
Muneyoshi Nanba
宗義 難波
Shinichi Murata
真一 村田
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.)
Mitsubishi Motors Corp
Original Assignee
Mitsubishi Motors Corp
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 Mitsubishi Motors Corp filed Critical Mitsubishi Motors Corp
Priority to JP16817889A priority Critical patent/JPH0333458A/en
Publication of JPH0333458A publication Critical patent/JPH0333458A/en
Pending legal-status Critical Current

Links

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
    • F05C2201/02—Light metals
    • F05C2201/021—Aluminium
    • 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

Abstract

PURPOSE:To raise the thermal conductivity of the piston head part and lessen the clearance at a skirt part by forming the skirt in Fe alloy constitution, and forming the lead in Al alloy constitution, both through power injection molding. CONSTITUTION:Thermoplastic resin binder, plasticizer, lubricant are added to Fe alloy powder and Al alloy powder, and they are kneaded and granulated into particles sizes 2-5mm. Then the Fe alloy particles 1a, its admixture 3a with Al alloy particles, and the Al alloy particles 2a are cast into an injection molding machine 4, the sequence named being identical to the order of injecting. The material is heated at approx. 150 deg.C, fluidified, cast into the cavity of a mold 5, and turned into three layers, i.e., a skirt 1, middle part 3, and land 2 in the sequence as named. The resultant is defatted and sintered to yield a work for piston, which is subjected to necessary processing. Thus the heat the lead 2 receives is transmitted effectively to a piston ring, which lessens the coefficient of thermal expansion of the skirt 1 to allow decreasing the clearance.

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、内燃機関特に自動車用に好適な粉末射出成
形ピストンに関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a powder injection molded piston suitable for internal combustion engines, particularly automobiles.

（従来の技術） 一般に、内燃機関のピストンは同一の材料で一体に形成
され加工されている。特に自動車用ピストンにあっては
高速運転を達成するために、軽量であること、更に頭部
における局所的過熱現象を避けるために熱伝導性の良い
ことが求められていて、組成材料と、してアルミニウム
合金が最も多く採用されている。(Prior Art) Generally, the pistons of internal combustion engines are integrally formed and machined from the same material. In particular, automobile pistons are required to be lightweight in order to achieve high-speed operation, and to have good thermal conductivity to avoid local overheating in the head. Aluminum alloys are the most commonly used.

（発明が解決しようとする課題） しかし、アルミニウム合金は鉄などに比べて熱膨張係数
が大きく、加工時寸法はガソリンエンジンにあっては、
直径で２５〜５０μｍ、ディーゼルエンジンでは５０〜
１００μ鳳のクリアランスを必要としているので、始動
直後や軽負荷時の運転中にピストン・スラップ現象が発
生したり、ブローパイガスなどの増大という不具合が生
じる問題が有り、過酷な運転条件でもピストンの焼付き
現象を回避するためにクリアランスは太き目に設定され
ているので益々上記不具合が助長される傾向にある。(Problem to be solved by the invention) However, aluminum alloy has a larger coefficient of thermal expansion than iron etc., and the dimensions when processed are not suitable for gasoline engines.
25-50μm in diameter, 50-50μm for diesel engines
Since a clearance of 100 μm is required, there are problems such as piston slap phenomenon occurring immediately after startup or during operation under light load, and problems such as an increase in blow-up gas, and piston seizure even under severe operating conditions. Since the clearance is set wide in order to avoid this phenomenon, the above-mentioned problem tends to be exacerbated.

（課題を解決するための手段） この発明は、従来技術の上記問題点を解決するためにな
されたもので、スカート部を鉄合金で、ランド部をアル
ミニウム合金で、スカート部とランド部との中間部を鉄
合金とアルミニウム合金との混合物で構成した粉末射出
成形によって得られたピストンにある。(Means for Solving the Problems) The present invention was made to solve the above-mentioned problems of the prior art.The skirt portion is made of iron alloy, the land portion is made of aluminum alloy, and the skirt portion and land portion are made of iron alloy. This piston is obtained by powder injection molding and has a middle portion made of a mixture of iron alloy and aluminum alloy.

（作　　用） 粉末射出成形によってスカート部は鉄合金の組成で、ラ
ンド部はアルミニウム合金の組成となるので、ピストン
頭部の受ける燃焼熱は熱伝導性の高いアルミニウム合金
によって効率良くピストンリングへ伝えられ、スカート
部は熱膨張係数の小さい鉄合金によって小さいクリアラ
ンスが得られるようになっている。(Function) Due to powder injection molding, the skirt part has an iron alloy composition and the land part has an aluminum alloy composition, so the combustion heat received by the piston head is efficiently transferred to the piston rings by the highly thermally conductive aluminum alloy. The skirt portion is made of an iron alloy with a small coefficient of thermal expansion, so that a small clearance can be obtained.

（実施例） 以下、図示の実施例により詳細に説明する。(Example) Hereinafter, a detailed explanation will be given with reference to illustrated embodiments.

第１図は射出成形機のピストンを示していて、符号１，
２及び３はそれぞれスカート部、ランド部およびこれら
両者の中間部を表わしている。そして、スカート部ｌは
鉄合金、ランド部２はアルミニウム合金、中間部３は鉄
合金およびアルミニウム合金の混合物からなっている。Figure 1 shows the pistons of an injection molding machine, with numbers 1,
2 and 3 represent a skirt portion, a land portion, and an intermediate portion between the two, respectively. The skirt portion 1 is made of an iron alloy, the land portion 2 is made of an aluminum alloy, and the intermediate portion 3 is made of a mixture of an iron alloy and an aluminum alloy.

ランド部２と中間部３との境界または中間部３とスカー
ト部１との境界はピストンの設計により異なるが、中間
部３はオイルリング溝の位置とピストン・ピン・ボスの
上縁の位置とを含む領域と考えれば良い。The boundary between the land portion 2 and the intermediate portion 3 or the boundary between the intermediate portion 3 and the skirt portion 1 differs depending on the design of the piston, but the intermediate portion 3 is located at the position of the oil ring groove and the upper edge of the piston pin boss. You can think of it as an area that includes.

かかるピストンを成形するために粉末射出成形法が用い
られる。すなわち、先ず８〜１０μｍの粒径の鉄合金粉
末およびアルミニウム合金粉末に、熱可塑性樹脂のバイ
ンダ、可塑剤、滑材を４０〜４５　ｖｏ１％添加し、混
練して粒径２〜５　ｍ／ｍに造粒しておき、約１５０℃
に過熱した射出成形機に投入する。Powder injection molding methods are used to mold such pistons. That is, first, 40 to 45 vol% of a thermoplastic resin binder, plasticizer, and lubricant are added to iron alloy powder and aluminum alloy powder with a particle size of 8 to 10 μm, and the mixture is kneaded to obtain a particle size of 2 to 5 m/m. Granulate at about 150℃
into a superheated injection molding machine.

第２図によく示すように、粉末射出成形機４内には射出
順に鉄台金粒１ａ、鉄合金粒とアルミニウム合金粒との
混合物３ａ及びアルミニウム合金粒２ａが投入される。As clearly shown in FIG. 2, iron base metal grains 1a, a mixture of iron alloy grains and aluminum alloy grains 3a, and aluminum alloy grains 2a are charged into the powder injection molding machine 4 in the order of injection.

これら三者の金属粉末の投入量はピストンの大きさ、形
状等によって決定されるべきものである。そして、１５
０℃で上記金属粉末は良好な流動状態を呈し、成形型５
内のキャビティに注入され、スカート部１．中間部３お
よびランド部２の順にて鉄合金、混合金属およびアルミ
ニウム合金の三層が得られる０次に、成形型より取り出
し不活性ガス中で４００〜６００℃に過熱して脱脂後焼
結すればピストン素材が完成する。以後従来の加工技術
が施されてピストン完成品ができ上がる。The amount of these three metal powders to be added should be determined depending on the size, shape, etc. of the piston. And 15
At 0°C, the metal powder exhibits a good fluidity, and the mold 5
It is injected into the cavity inside the skirt part 1. Three layers of iron alloy, mixed metal and aluminum alloy are obtained in the order of intermediate part 3 and land part 2.Next, it is taken out from the mold and heated to 400 to 600°C in an inert gas, degreased and sintered. Then the piston material is completed. Thereafter, conventional processing techniques are applied to complete the piston.

（発明の効果） この発明は１以上のように、ランド部がアルミニウム合
金からなり、スカート部が鉄合金かななっているので、
ピストン頭部の受ける熱は高い熱伝導性により直ちにピ
ストンリングへ伝えられ、スカート部は熱膨張係数が小
さいため僅かなりリアランスでシリンダ面を摺動・往復
することができ、ピストン・スランプ、ブローパイガス
などの減少という効果を発揮するとともに、射出成形法
によって形成されるので、ヒケ、巣などが発生せず歩留
まりがよいという効果をも有するものである。(Effects of the Invention) As described in item 1 or above, the land portion is made of an aluminum alloy and the skirt portion is made of an iron alloy.
The heat received by the piston head is immediately transferred to the piston ring due to its high thermal conductivity, and the skirt part has a small coefficient of thermal expansion, so it can slide and reciprocate on the cylinder surface with very little clearance. In addition, since it is formed by injection molding, there are no sink marks, cavities, etc., and the yield is high.

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

第１図はこの発明による射出成形機のピストンを示す側
面図、第２図は粉末射出成形を説明するための概念図で
ある。 ■・・・スカート部、１ａ・・・鉄合金粒、２・・・ラ
ンド部、２ａ・・・アルミニウム合金粒、３・・・中間
部、３ａ・・・鉄合金粒とアルミニウム合金粒との混合
物、４・・・粉末射出成形機、５・・・成形型。FIG. 1 is a side view showing a piston of an injection molding machine according to the present invention, and FIG. 2 is a conceptual diagram for explaining powder injection molding. ■... Skirt part, 1a... Iron alloy grains, 2... Land part, 2a... Aluminum alloy grains, 3... Intermediate part, 3a... Between iron alloy grains and aluminum alloy grains Mixture, 4... Powder injection molding machine, 5... Molding mold.

Claims (1)

【特許請求の範囲】[Claims] 鉄合金粉末およびアルミニウム合金粉末を射出成形する
ことにより、スカート部を鉄合金で、ランド部をアルミ
ニウム合金で、スカート部とランド部との中間部を鉄合
金とアルミニウム合金との混合物で構成したことを特徴
とする粉末射出成形ピストン。By injection molding iron alloy powder and aluminum alloy powder, the skirt part is made of iron alloy, the land part is made of aluminum alloy, and the intermediate part between the skirt part and land part is made of a mixture of iron alloy and aluminum alloy. A powder injection molded piston featuring:
JP16817889A 1989-06-29 1989-06-29 Powder injection molded piston Pending JPH0333458A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16817889A JPH0333458A (en) 1989-06-29 1989-06-29 Powder injection molded piston

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16817889A JPH0333458A (en) 1989-06-29 1989-06-29 Powder injection molded piston

Publications (1)

Publication Number Publication Date
JPH0333458A true JPH0333458A (en) 1991-02-13

Family

ID=15863236

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16817889A Pending JPH0333458A (en) 1989-06-29 1989-06-29 Powder injection molded piston

Country Status (1)

Country Link
JP (1) JPH0333458A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001330149A (en) * 2000-03-31 2001-11-30 Sauer Danfoss Inc Closed cavity hydraulic piston and method of making it
JP2002268563A (en) * 2001-03-06 2002-09-20 Ohtsu Tire & Rubber Co Ltd :The Illuminator
GB2398797A (en) * 2000-03-09 2004-09-01 Smith International Composite material
US7211218B2 (en) 2000-03-09 2007-05-01 Smith International, Inc. Polycrystalline diamond carbide composites
CN113996789A (en) * 2021-09-24 2022-02-01 河南中原吉凯恩气缸套有限公司 Manufacturing method of metal injection molding steel piston

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2398797A (en) * 2000-03-09 2004-09-01 Smith International Composite material
GB2398797B (en) * 2000-03-09 2004-10-13 Smith International Polycrystalline diamond carbide composites
US7211218B2 (en) 2000-03-09 2007-05-01 Smith International, Inc. Polycrystalline diamond carbide composites
US7647992B2 (en) 2000-03-09 2010-01-19 Smith International, Inc. Polycrystalline diamond carbide composites
JP2001330149A (en) * 2000-03-31 2001-11-30 Sauer Danfoss Inc Closed cavity hydraulic piston and method of making it
JP2002268563A (en) * 2001-03-06 2002-09-20 Ohtsu Tire & Rubber Co Ltd :The Illuminator
CN113996789A (en) * 2021-09-24 2022-02-01 河南中原吉凯恩气缸套有限公司 Manufacturing method of metal injection molding steel piston
CN113996789B (en) * 2021-09-24 2023-08-18 河南中原吉凯恩气缸套有限公司 Manufacturing method of metal injection molding steel piston

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