JP3596379B2

JP3596379B2 - Resin gear and manufacturing method thereof

Info

Publication number: JP3596379B2
Application number: JP30842699A
Authority: JP
Inventors: 昭治沢井; 伸一田原
Original assignee: Shin Kobe Electric Machinery Co Ltd
Current assignee: Resonac Corp
Priority date: 1999-10-29
Filing date: 1999-10-29
Publication date: 2004-12-02
Anticipated expiration: 2019-10-29
Also published as: JP2001124183A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車部品等として適した樹脂製歯車及びその製造法に関する。
【０００２】
【従来の技術】
上記樹脂製歯車は、歯の噛み合い時の騒音発生を抑えるために、金属製歯車と噛み合う相手歯車として用いられ、耐摩耗性に優れ、高い強度が要求される。従来、樹脂製歯車として、樹脂を含浸した補強繊維基材のリング状成形体に歯を加工したものが提案されている。例えば、次のような技術である。
（１）補強繊維をフェノール樹脂粉末と共に水中に分散して抄造したシート状繊維基材を重ね巻きし、中心には空間を残したリング状の補強繊維基材とする。このリング状の補強繊維基材を厚さ方向に加熱加圧成形してリング状成形体とし、このリング状成形体の周囲に切削加工により歯を形成する（特開平１０−２８６８８８号公報）。
（２）補強繊維を束ねた糸を織って又は編んで筒状体を構成し、この筒状体を端部から軸方向に巻き上げてリング状の補強繊維基材とする。そして、リング状の補強繊維基材に樹脂を含浸して、厚さ方向に加熱加圧成形又は加圧成形してリング状成形体とし、このリング状成形体の周囲に切削加工により歯を形成する（特開平８−１５６１２４号公報）。
【０００３】
これらの技術においては、リング状の補強繊維基材の周方向のつなぎ目が目立たないか、つなぎ目が全くないので、特定の箇所で強度が低下するという問題がない。
【０００４】
【発明が解決しようとする課題】
上記（１）の技術では、シート状繊維基材を構成している補強繊維は、殆どが当該基材の面方向に向いている。従って、このシート状繊維基材を重ね巻きして構成したリング状の補強繊維基材においては、殆どの補強繊維が周方向に配向することになる。この補強繊維の配向状態は、リング状成形体にもそのままもち込まれる。リング状成形体中の補強繊維同士は周方向では交叉している部分があるものの径方向では交叉や絡み合いが極めて少なく、歯車駆動中の歯面に加わる応力を有効に受けとめる作用をしているとは言い難い面がある。
上記（２）の技術では、補強繊維を束ねた糸を織ったり編んだりするため織目や編目ができ、（１）の技術に比べて補強繊維の粗密が大きくなる。また、補強繊維を束ねた糸の内部まで樹脂が浸透しにくい。補強繊維を束ねた糸を織ったり編んだりした基材を使用しているため、歯車の強度は十分に大きいわけであるが、さらに、補強繊維に粗密がなく樹脂が補強繊維間に十分に浸透したものであることが望まれる。
また、補強繊維として芳香族ポリアミド繊維など高強度の繊維を採用した場合には、その繊維を収束した糸が歯の切削加工時に切断されずに切削面に残りやすい。
【０００５】
本発明が解決しようとする課題は、上記のようにつなぎ目の目立たないリング状補強繊維基材を用い、そのリング状成形体で歯部を構成した樹脂製歯車において、補強繊維が歯車の歯面に加わる応力を有効に受けとめられるようにすることであり、補強繊維の粗密を作らず補強繊維間に樹脂が十分に浸透した樹脂製歯車とし、長寿命の樹脂製歯車とすることである。
【０００６】
【課題を解決するための手段】
本発明に係る樹脂製歯車は、樹脂を含浸した補強繊維基材のリング状成形体により歯部を構成したものであって、上記課題を解決するために次のような構成を有する。
まず、前記補強繊維基材は、帯状のフェルトを重ね巻きして筒状にし、さらにその筒状体を軸方向に蛇腹状に折り畳んだ構成を有する。前記帯状のフェルトは、厚さ方向を向いた補強繊維が平面方向を向いた補強繊維同士を結合した構成を有するものである。
【０００７】
このような補強繊維基材はリング状であって、周方向に基材のつなぎ目が目立たないないのは勿論である。リング状の補強繊維基材には、その周方向だけでなく径方向を向いた補強繊維も多数存在することになり、このような繊維の配置状態がリング状成形体にもそのままもち込まれる。駆動中の歯車の歯面に加わる応力を径方向を向いた補強繊維により有効に受けとめることができる。そして、フェルトを構成する補強繊維同士の間も、前記径方向を向いた補強繊維で結合されているので、補強繊維を束ねた糸を織ったり編んだりした補強繊維基材を採用する場合に準じた機械強度の確保を期待できる。
帯状のフェルトを重ね巻きした上記筒状体は、重ね巻きしたフェルト層間が一体になっていない。しかし、かえってこのことが、筒状体を軸方向に圧縮して蛇腹状にきれいに折り畳む上で好都合となっている。筒状体を蛇腹状にきれいに折り畳めば補強繊維の配向は乱れない。重ね巻きしたフェルト層間が一体になっていなくとも、蛇腹状に折り畳むことによってフェルト層間で剥がれる心配もなくなる。
さらに、フェルトには、補強繊維を束ねた糸を織ったり編んだりした補強繊維基材を採用した場合に見られた樹脂の浸透不十分の問題や切削加工性が悪くなる問題は見られない。補強繊維は樹脂中に均一に分散しており粗密がないからである。従って、長寿命の樹脂製歯車とすることができる。
【０００８】
上記の樹脂製歯車は、次の工程を経て製造する。
まず、補強繊維の集積層にニードリングを施し、ニードリングにより厚さ方向に配向させた補強繊維で平面方向を向いた補強繊維同士を結合した帯状のフェルトを準備する。ニードリングにより生成しフェルト厚さ方向を向いた補強繊維は、平面方向に配向している補強繊維だけでは得られない補強繊維同士の大きな結合力を生む。次に、帯状のフェルトを重ね巻きして筒状にし、さらにその筒状体を軸方向に蛇腹状に折り畳んでリング状の補強繊維基材を形成する。蛇腹状に折り畳むことにより、重ね巻きしたフェルトの層間を一体化したのと同じ状態にすることができる。蛇腹状に折り畳む前は、フェルト層間は一体化されておらず、一体化されていないからこそ、蛇腹状に折り畳む際にフェルト層間に滑りが生じて、きれいに蛇腹状に折り畳むことができ、折り畳み後はフェルト層間を一体化したのと同じ状態にできるのである。帯状のフェルトを構成している補強繊維同士は強固に結合されているので、蛇腹状に折り畳むに際して補強繊維の配向が乱れることはない。
このリング状の補強繊維基材に樹脂を含浸し、成形金型内で加熱加圧成形又は加熱成形してリング状成形体とした後、リング状成形体の周囲に歯を加工する。
【０００９】
別の製造法では、まず、樹脂の粒子を含む補強繊維の集積層にニードリングを施して上記と同様に補強繊維同士を結合した帯状のフェルトを準備する。この帯状のフェルトを用いて、上記と同様にリング状の補強繊維基材を形成する。このリング状の補強繊維基材は、既に樹脂の粒子を含んでいるので、そのまま加熱加圧成形してリング状成形体とする。
【００１０】
【発明の実施の形態】
フェルトを構成する補強繊維には、綿や麻等の天然繊維、ポリエステル、フッ素樹脂、パラ系芳香族ポリアミド、メタ系芳香族ポリアミド等の有機繊維、ガラスやステンレス等の無機繊維を適宜採用することができる。これらの繊維は、歯車の特性を勘案して、単独で採用してもよいし複数種類を組合せて採用してもよい。
【００１１】
補強繊維の集積には、水中で抄造する湿式と気中で散布して集積する乾式のいずれの手段も採用できるが、乾式の方が廃液処理の工程を必要としないので都合がよい。補強繊維の集積体に施すニードリングは、採用する補強繊維の種類に応じて植針密度を適宜設定する。切断を起こしやすいガラス繊維や金属繊維に対しては植針密度を小さくしなければならないが、切断を起こしにくい芳香族ポリアミド繊維等に対しては植針密度を高くすることができる。植針密度の大小で、フェルトの厚さ方向を向く補強繊維の量を変えることができ、フェルトの密度と引張り強度を適宜調整する。
適度に引張り強度を付与した帯状のフェルトを重ね巻きして筒状にし、さらにその筒状体を軸方向に蛇腹状に折り畳んだリング状の補強繊維基材を形成する。
【００１２】
リング状成形体の成形は、上記補強繊維基材に適宜の樹脂を含浸して行なう。例えば、補強繊維基材にフェノール樹脂を予め含浸乾燥しておき、これを成形金型に投入し中心には金属製ブッシュを配置して加熱加圧成形をする。別の方法では、補強繊維基材を成形金型に投入し中心には金属製ブッシュを配置して成形金型を閉じ、液状樹脂（架橋ポリアミノアミド、エポキシ樹脂、ポリイミドなど）を注入して加熱成形する。
さらに別の方法では、フェルトを準備するときに、湿式では水中で補強繊維を抄造する段階で、乾式では気中で補強繊維を散布・集積する段階でフェノール樹脂等の微粒子を混入する。このような樹脂微粒子含有フェルトを用いて形成したリング状の補強繊維基材は、成形金型に投入してそのまま加熱加圧成形することができる。
リング状の補強繊維基材一つで一つの歯車を成形してもよいし、リング状の補強繊維基材を複数個重ねて一体に成形し、歯幅の大きい歯車の製造に対処することもできる。
【００１３】
【実施例】
実施例１
パラ系アラミド繊維原綿（繊維径５〜２０μｍ，繊維長５０ｍｍ）とメタ系アラミド繊維原綿（繊維径５〜２０μｍ，繊維長５０ｍｍ）を重量比で５０／５０の割合で気中に散布して集積し、これにニードリングを施して、幅２０００ｍｍ，厚さ３ｍｍ，単位重量１５０ｇ／ｍ^２のフェルト１を準備した。図４に示すように、フェルト１は、厚さ方向を向いた補強繊維１１が平面方向を向いた補強繊維１２同士を結合した構成を有している。図１（ａ）に示すように、このフェルト１を１００ｍｍの幅に裁断し所定の軸に４回重ね巻きし、外径９０ｍｍ，内径６０ｍｍ，高さ１００ｍｍの筒状体２とする。そして、図１（ｂ）に示すように、筒状体２を予備成形型２０内で軸方向に圧縮し、蛇腹状に折り畳んで外径９０ｍｍ，内径６０ｍｍ，厚さ２０ｍｍのリング状の補強繊維基材３とする。図２は、図１（ｂ）に示した補強繊維基材３をＡ−Ａ’線で切断したところを示しており、フェルト１は蛇腹状にきれいに折り畳まれた状態になっている。
次に、図３に示すように、２個積み重ねたリング状の補強繊維基材３を、その中心に配置した金属製のブッシュ４とともに２００℃の成形金型５に投入し、型締めしてから架橋ポリアミノアミドを注入して加熱成形した。歯車の歯は、補強繊維基材３で成形されたリング状成形体の周囲に機械切削により形成し、樹脂製歯車とした。その特性を表１に示す。
【００１４】
従来例１
パラ系アラミド繊維チョップ（繊維径５〜２０μｍ，繊維長３ｍｍ）及びメタ系アラミド繊維チョップ（繊維径５〜２０μｍ，繊維長３ｍｍ）を、重量比で５０／５０の割合で水に分散し、これを連続抄造して幅９６０ｍｍ，厚さ３ｍｍ，単位重量１５０ｇ／ｍ^２のシート状成形材料とした。このシート状成形材料を１００ｍｍの幅に裁断し所定の軸に４回重ね巻きして、外径９０ｍｍ，内径６０ｍｍの筒状体とする。この筒状体を予備成形型内で軸方向に圧縮し、外径９０ｍｍ，内径６０ｍｍ，厚さ２０ｍｍのリング状の補強繊維基材とする。このシート状成形材料は、補強繊維同士の結合が弱く、重ね巻きした筒状体を軸方向に圧縮したとききれいに蛇腹状に折り畳むことができず、繊維の配向が乱れた。
上記リング状の補強繊維基材を用いて、以下実施例と同様に樹脂製歯車とした。その特性を表１に示す。
【００１５】
従来例２（図５参照）
パラ系アラミド繊維及びメタ系アラミド繊維を、重量比で５０／５０の割合で混紡した糸をニット編みして筒状体６を構成した。この筒状体６を端部から軸方向に巻き上げて、外径９０ｍｍ，内径６０ｍｍ，厚さ２０ｍｍのリング状の補強繊維基材３とする。
上記リング状の補強繊維基材を用いて、以下実施例と同様に樹脂製歯車とした。その特性を表１に示す。
【００１６】
表１に示した各特性の測定は次のようにして行なった。尚、各例の樹脂製歯車の樹脂中に占める補強繊維の含有量はいずれも同じである。
曲げ強度は、製造した樹脂製歯車の歯部三箇所から切り出した円弧状試料の曲げ強度（初期強度）を測定したものである。
実装耐久時間は、自動車エンジンのギヤ加速テスト（回転数：６０００ｒｐｍ，油温１３０℃，歯元負荷応力２５５ＭＰａ）での耐久時間を測定した。１０個の試料の測定値の最大値と最小値を示す。
【００１７】
【表１】

【００１８】
【発明の効果】
上述のように、本発明に係る樹脂製歯車は、補強繊維の糸を織ったり編んだりしない点で従来例１と同様の補強繊維基材構成でありながら、大きな機械強度を有している。補強繊維同士が強固に結合されたフェルトを重ね巻きした筒状体を蛇腹状に折り畳んだ構成が有効に作用しており、その強度は、補強繊維の糸を編んだ補強繊維基材構成である従来例２に比べると多少劣るものの、それに匹敵するものである。そして、補強繊維の糸を織ったり編んだ場合に見られた補強繊維の粗密がなく、水分や油分が歯車表面から内部に侵入しにくいので、耐久性がさらに向上している。
【図面の簡単な説明】
【図１】本発明に係る実施例において、フェルトからリング状の補強繊維基材をを製造する工程を示す説明図である。
【図２】図１（ｂ）に示した補強繊維基材をＡ−Ａ’に沿って裁断したところを示す説明図である。
【図３】本発明に係る実施例において補強繊維基材を成形する様子を示す断面説明図である。
【図４】フェルトを構成する補強繊維の配向状態を示す概念図である。
【図５】従来例２において、樹脂製歯車を製造する工程の一部を示す説明図である。
【符号の説明】
１：フェルト
１１：厚さ方向を向いた補強繊維
１２：平面方向を向いた補強繊維
２：筒状体
３：リング状の補強繊維基材
４：ブッシュ
５：成型金型
６：筒状体
２０：予備成形型[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resin gear suitable as an automobile part or the like and a method for manufacturing the same.
[0002]
[Prior art]
The resin gear is used as a mating gear that meshes with a metal gear in order to suppress the generation of noise when the teeth mesh with each other, and is required to have excellent wear resistance and high strength. BACKGROUND ART Conventionally, as a resin gear, there has been proposed a gear formed by processing teeth into a ring-shaped molded body of a reinforcing fiber base material impregnated with a resin. For example, the following technology is used.
(1) A sheet-like fiber base material formed by dispersing reinforcing fibers in water together with a phenolic resin powder is wound in a stack, and a ring-shaped reinforcing fiber base body is left with a space in the center. This ring-shaped reinforcing fiber base material is heated and pressed in the thickness direction to form a ring-shaped molded body, and teeth are formed around the ring-shaped molded body by cutting (Japanese Patent Laid-Open No. 10-286888).
(2) A tubular body is formed by weaving or knitting a yarn obtained by bundling reinforcing fibers, and the tubular body is rolled up in an axial direction from an end to form a ring-shaped reinforcing fiber base material. Then, a resin is impregnated into the ring-shaped reinforcing fiber base material, and heated and pressed or pressed in the thickness direction to form a ring-shaped body, and teeth are formed around the ring-shaped body by cutting. (JP-A-8-156124).
[0003]
In these techniques, the circumferential seam of the ring-shaped reinforcing fiber base material is inconspicuous or has no seam, so there is no problem that the strength is reduced at a specific location.
[0004]
[Problems to be solved by the invention]
In the technique (1), most of the reinforcing fibers constituting the sheet-like fiber base are oriented in the plane direction of the base. Therefore, in the ring-shaped reinforcing fiber substrate formed by laminating the sheet-like fiber substrates, most of the reinforcing fibers are oriented in the circumferential direction. The orientation state of the reinforcing fiber is directly applied to the ring-shaped molded body. Although the reinforcing fibers in the ring-shaped molded body have crossing parts in the circumferential direction, there is very little crossing or entanglement in the radial direction, and it has an effect of effectively receiving the stress applied to the tooth surface during gear driving. Is hard to say.
In the technique (2), a weave or stitch is formed by weaving or knitting a yarn obtained by bundling reinforcing fibers, and the density of the reinforcing fibers becomes larger than that in the technique (1). In addition, the resin hardly penetrates into the inside of the yarn in which the reinforcing fibers are bundled. The strength of the gears is large enough because the base material is made of woven or knitted yarn that bundles reinforcing fibers, but the reinforcing fibers are not dense and dense, and the resin penetrates sufficiently between the reinforcing fibers. It is hoped that it is done.
When a high-strength fiber such as an aromatic polyamide fiber is used as the reinforcing fiber, a thread converging the fiber is likely to remain on the cutting surface without being cut at the time of cutting the teeth.
[0005]
The problem to be solved by the present invention is to use a ring-shaped reinforcing fiber base material with inconspicuous joints as described above, and in a resin gear having a tooth portion formed by the ring-shaped molded product, the reinforcing fibers are formed on the tooth surface of the gear. In order to effectively receive the stress applied to the resin gears, the resin gears are formed such that the resin is sufficiently penetrated between the reinforcing fibers without making the reinforcing fibers dense and dense, and the resin gears have a long life.
[0006]
[Means for Solving the Problems]
The resin gear according to the present invention has a tooth portion formed of a ring-shaped molded body of a reinforcing fiber base material impregnated with a resin, and has the following configuration in order to solve the above problem.
First, the reinforcing fiber base material has a configuration in which a belt-like felt is overlapped and wound into a tubular shape, and the tubular body is folded in a bellows shape in the axial direction. The belt-like felt has a configuration in which reinforcing fibers oriented in the thickness direction are combined with reinforcing fibers oriented in the planar direction.
[0007]
Such a reinforcing fiber substrate has a ring shape, and it is a matter of course that the joint of the substrates is not conspicuous in the circumferential direction. In the ring-shaped reinforcing fiber base material, a large number of reinforcing fibers not only in the circumferential direction but also in the radial direction are present, and the arrangement state of such fibers is directly applied to the ring-shaped molded body. The stress applied to the tooth surface of the driven gear can be effectively received by the reinforcing fibers oriented in the radial direction. Since the reinforcing fibers constituting the felt are also connected by the reinforcing fibers oriented in the radial direction, the reinforcing fibers are woven or knitted with a bundle of reinforcing fibers. It can be expected to secure the mechanical strength.
In the above-mentioned tubular body in which the belt-shaped felt is overlapped and wound, the overlapped felt layers are not integrated. However, this is rather convenient for compressing the cylindrical body in the axial direction and folding it neatly in a bellows shape. If the tubular body is folded neatly in a bellows shape, the orientation of the reinforcing fibers is not disturbed. Even if the wrapped felt layers are not integrated, there is no fear of peeling between the felt layers by folding in a bellows shape.
Further, the felt does not have the problem of insufficient resin penetration or the problem of poor machinability, which is observed when a reinforcing fiber base material obtained by weaving or knitting a yarn obtained by bundling reinforcing fibers is used. This is because the reinforcing fibers are uniformly dispersed in the resin and have no density. Therefore, a resin gear having a long life can be obtained.
[0008]
The above-mentioned resin gear is manufactured through the following steps.
First, a needling is applied to the accumulation layer of the reinforcing fibers, and a belt-like felt in which the reinforcing fibers oriented in the plane direction are joined by the reinforcing fibers oriented in the thickness direction by the needling is prepared. The reinforcing fibers generated by needling and oriented in the direction of the thickness of the felt generate a large bonding force between the reinforcing fibers that cannot be obtained only by the reinforcing fibers oriented in the planar direction. Next, a belt-shaped felt is wound up into a tubular shape, and the tubular body is folded in a bellows shape in the axial direction to form a ring-shaped reinforcing fiber base material. By folding in a bellows shape, the layers of the wrapped felt can be brought into the same state as integrated. Before folding in a bellows shape, the felt layers are not integrated, and because they are not integrated, slippage occurs between the felt layers when folded in a bellows shape, so that it can be folded cleanly in a bellows shape, and after folding Can be in the same state as the integrated felt layers. Since the reinforcing fibers constituting the belt-like felt are strongly bonded to each other, the orientation of the reinforcing fibers is not disturbed when folded in a bellows shape.
The ring-shaped reinforcing fiber base material is impregnated with a resin, and is heated and pressed or heated and molded in a molding die to form a ring-shaped molded body, and then teeth are processed around the ring-shaped molded body.
[0009]
In another manufacturing method, first, a band-like felt in which reinforcing fibers are bonded to each other is prepared by performing needling on an integrated layer of reinforcing fibers containing resin particles in the same manner as described above. Using this belt-like felt, a ring-shaped reinforcing fiber base is formed in the same manner as described above. Since this ring-shaped reinforcing fiber base already contains resin particles, it is heated and pressed to form a ring-shaped formed body.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Natural fibers such as cotton and hemp, organic fibers such as polyester, fluororesin, para-aromatic polyamide and meta-aromatic polyamide, and inorganic fibers such as glass and stainless steel should be appropriately used as the reinforcing fibers constituting the felt. Can be. These fibers may be employed alone or in combination of plural types in consideration of the characteristics of the gear.
[0011]
In order to accumulate the reinforcing fibers, either a wet method of paper-making in water or a dry method of spraying and accumulating in the air can be adopted, but the dry method is more convenient because a waste liquid treatment step is not required. Needling applied to the aggregate of reinforcing fibers appropriately sets the needle placement density according to the type of reinforcing fibers to be employed. Needle densities must be reduced for glass fibers or metal fibers that are prone to cutting, but can be increased for aromatic polyamide fibers or the like that are not prone to cutting. The amount of the reinforcing fiber oriented in the thickness direction of the felt can be changed depending on the size of the needle implantation density, and the density and the tensile strength of the felt are appropriately adjusted.
A belt-like felt having an appropriate tensile strength is overlapped and wound into a tubular shape, and the tubular body is folded in a bellows shape in the axial direction to form a ring-shaped reinforcing fiber base material.
[0012]
The molding of the ring-shaped molded article is performed by impregnating the reinforcing fiber base material with an appropriate resin. For example, a phenol resin is impregnated and dried in advance on a reinforcing fiber base material, and the phenol resin is put into a molding die. In another method, a reinforcing fiber base is put into a molding die, a metal bush is placed at the center, the molding die is closed, and a liquid resin (crosslinked polyaminoamide, epoxy resin, polyimide, etc.) is injected and heated. Mold.
In still another method, when preparing a felt, fine particles such as phenolic resin are mixed in the wet process at the stage of forming reinforcing fibers in water, and in the dry process at the stage of spraying and accumulating the reinforcing fibers in the air. The ring-shaped reinforcing fiber base material formed using such a resin fine particle-containing felt can be charged into a molding die and directly heated and pressed.
One gear may be formed from one ring-shaped reinforcing fiber base material, or a plurality of ring-shaped reinforcing fiber base materials may be integrally molded to cope with the manufacture of a gear having a large tooth width. it can.
[0013]
【Example】
Example 1
Para-aramid fiber raw cotton (fiber diameter 5 to 20 μm, fiber length 50 mm) and meta-aramid fiber raw cotton (fiber diameter 5 to 20 μm, fiber length 50 mm) are dispersed in the air at a weight ratio of 50/50 and accumulated. This was subjected to needling to prepare a felt 1 having a width of 2000 mm, a thickness of 3 mm, and a unit weight of 150 g / m ² . As shown in FIG. 4, the felt 1 has a configuration in which reinforcing fibers 11 oriented in a thickness direction are connected to reinforcing fibers 12 oriented in a plane direction. As shown in FIG. 1 (a), the felt 1 is cut into a width of 100 mm and wound around a predetermined shaft four times to form a cylindrical body 2 having an outer diameter of 90 mm, an inner diameter of 60 mm and a height of 100 mm. Then, as shown in FIG. 1 (b), the cylindrical body 2 is compressed in the axial direction in the preforming mold 20 and folded in a bellows shape to form a ring-shaped reinforcing fiber having an outer diameter of 90 mm, an inner diameter of 60 mm and a thickness of 20 mm. The substrate 3 is used. FIG. 2 shows a state where the reinforcing fiber base material 3 shown in FIG. 1 (b) is cut along the line AA ′, and the felt 1 is in a state of being neatly folded in a bellows shape.
Next, as shown in FIG. 3, the ring-shaped reinforcing fiber base material 3 stacked together is put into a molding die 5 at 200 ° C. together with a metal bush 4 arranged at the center thereof, and the mold is clamped. Was injected with a cross-linked polyaminoamide and molded by heating. The gear teeth were formed by mechanical cutting around a ring-shaped molded body formed of the reinforcing fiber base material 3 to obtain a resin gear. The characteristics are shown in Table 1.
[0014]
Conventional example 1
A para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm) and a meta-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm) are dispersed in water at a weight ratio of 50/50. Was continuously formed into a sheet-shaped molding material having a width of 960 mm, a thickness of 3 mm, and a unit weight of 150 g / m ² . This sheet-shaped molding material is cut into a width of 100 mm and wound up four times around a predetermined shaft to form a cylindrical body having an outer diameter of 90 mm and an inner diameter of 60 mm. This cylindrical body is axially compressed in a preforming mold to form a ring-shaped reinforcing fiber base material having an outer diameter of 90 mm, an inner diameter of 60 mm, and a thickness of 20 mm. In this sheet-shaped molding material, the bonding between the reinforcing fibers was weak, and when the lap-wrapped tubular body was compressed in the axial direction, it could not be neatly folded in a bellows shape, and the orientation of the fibers was disordered.
Using the ring-shaped reinforcing fiber base material, a resin gear was formed in the same manner as in the following examples. The characteristics are shown in Table 1.
[0015]
Conventional example 2 (see FIG. 5)
A yarn obtained by blending para-aramid fibers and meta-aramid fibers at a weight ratio of 50/50 was knit-knitted to form a tubular body 6. The cylindrical body 6 is wound up in the axial direction from the end to form a ring-shaped reinforcing fiber base material 3 having an outer diameter of 90 mm, an inner diameter of 60 mm, and a thickness of 20 mm.
Using the ring-shaped reinforcing fiber base material, a resin gear was formed in the same manner as in the following examples. The characteristics are shown in Table 1.
[0016]
The measurement of each characteristic shown in Table 1 was performed as follows. The content of the reinforcing fibers in the resin of the resin gears of each example is the same.
The bending strength is obtained by measuring the bending strength (initial strength) of an arc-shaped sample cut from three tooth portions of the manufactured resin gear.
The mounting durability time was measured by a gear acceleration test of an automobile engine (rotation speed: 6000 rpm, oil temperature 130 ° C., tooth root load stress 255 MPa). The maximum and minimum values of the measured values of ten samples are shown.
[0017]
[Table 1]

[0018]
【The invention's effect】
As described above, the resin gear according to the present invention has the same mechanical strength as the conventional reinforcing fiber base in that the reinforcing fiber yarn is not woven or knitted, but has high mechanical strength. A configuration in which a tubular body formed by overlapping and winding a felt in which reinforcing fibers are firmly bonded to each other is folded in a bellows shape is effectively acting, and the strength is a reinforcing fiber base structure in which reinforcing fiber yarns are knitted. Although slightly inferior to Conventional Example 2, it is comparable. In addition, the durability of the reinforcing fibers is further improved because there is no coarse or dense reinforcing fibers as seen when weaving or knitting the reinforcing fibers, and it is difficult for moisture and oil to enter the inside from the gear surface.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a step of manufacturing a ring-shaped reinforcing fiber base material from felt in an example according to the present invention.
FIG. 2 is an explanatory view showing a state where the reinforcing fiber base material shown in FIG. 1 (b) is cut along AA ′.
FIG. 3 is an explanatory sectional view showing a state in which a reinforcing fiber base material is molded in an example according to the present invention.
FIG. 4 is a conceptual diagram illustrating an orientation state of reinforcing fibers constituting a felt.
FIG. 5 is an explanatory view showing a part of a process of manufacturing a resin gear in Conventional Example 2.
[Explanation of symbols]
1: Felt 11: Reinforcement fiber oriented in the thickness direction 12: Reinforcement fiber oriented in the plane direction 2: Cylindrical body 3: Ring-shaped reinforcement fiber base material 4: Bush 5: Mold 6: Cylindrical body 20 ： Preforming mold

Claims

In a resin gear having a tooth portion formed by a ring-shaped molded body of a reinforcing fiber base material impregnated with a resin,
The reinforcing fiber base material has a configuration in which a belt-shaped felt is overlapped and wound into a tubular shape, and the tubular body is further folded in a bellows shape in the axial direction,
A resin gear, wherein the belt-like felt has a configuration in which reinforcing fibers oriented in a thickness direction are connected between reinforcing fibers oriented in a plane direction.

A method for manufacturing a resin gear, comprising the following steps (1) to (4):
(1) a step of performing needling on an accumulation layer of reinforcing fibers, and preparing a belt-like felt in which reinforcing fibers oriented in a planar direction are bonded by reinforcing fibers oriented in the thickness direction by needling;
(2) forming a ring-shaped reinforcing fiber base material by laminating and winding the belt-like felt into a cylindrical shape, and further folding the cylindrical body in a bellows-like manner in the axial direction;
(3) a step of impregnating the ring-shaped reinforcing fiber base material with a resin, and performing heat-pressure molding or heat molding in a molding die to form a ring-shaped molded body;
(4) A step of processing teeth around the ring-shaped molded body.

A method for manufacturing a resin gear, comprising the following steps (1) to (4):
(1) Needling is performed on an accumulation layer of reinforcing fibers containing resin fine particles, and a belt-like felt in which reinforcing fibers oriented in a plane direction are joined by reinforcing fibers oriented in the thickness direction by needling is prepared. Process,
(2) forming a ring-shaped reinforcing fiber base material by laminating and winding the belt-like felt into a cylindrical shape, and further folding the cylindrical body in a bellows-like manner in the axial direction;
(3) a step of preparing a ring-shaped molded body by heat-pressing or heat-forming the ring-shaped reinforcing fiber base in a molding die;
(4) A step of processing teeth around the ring-shaped molded body.