JP2004148525A - Cylindrical member, cylindrical member apparatus and mold for molding cylindrical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding a cylindrical member having a good driving performance and stable characteristics even against external force. <P>SOLUTION: A cylindrical cam frame molded by this mold has a cam channel with a relatively small flank angle on its inner peripheral part. In the mold, an eight-divided inner slide mold is applied for making it possible to mold a cam channel with a flank angle smaller than the above described flank angle. The mold has a center core 3, and four first slide cores 4A-4D and four second slide cores 5A-5D respectively arranged around the core 3. Inclined dovetail grooves 3a and 3b are provided on the center core 3 while dovetail parts 4a and 5b to be inserted into the dovetail grooves 3a and 3b are provided on the first and second slide cores. When the center core 3 is retreats during mold opening after the cam frame is molded, the first and second slide cores are driven by the dovetail grooves to slide so as to be narrowed inward to enable the mold release from the cam channel of the cam frame. <P>COPYRIGHT: (C)2004,JPO

Description

である。
【００７９】
センターコア３の軸心Ｃ０ 方向のスライド量Ｓとすると（図５）、上記移動距離Ｌ１ ，Ｌ２ は、
Ｌ１ ＝Ｓ×ｔａｎα …（３）
Ｌ２ ＝Ｓ×ｔａｎβ …（４）
である。一方、上記点Ｐ１ ，Ｐ２ ，Ｐ３ でできる三角形から、
Ｌ２ ×ｃｏｓε＝Ｌ１ ＋Ｌ２ ×ｓｉｎε×ｔａｎγ …（５）
が得られる。
【００８０】
上記式（２）〜（５）より、傾斜角度α、β、γの関係は、

となる。
【００８１】
但し、上記（６）式の通りに内スライド金型１２を製作しても、その加工誤差などにより、第１スライドコア４Ａ〜４Ｄと第２スライドコア５Ａ〜５Ｄが干渉して、型の作動に支障を来すことがある。そこで、上記干渉を確実に避けるため、経験上、次式を満足させることとする。すなわち、
β≧ｔａｎ^−１｛２^１／２×ｔａｎα／（１−ｔａｎγ）｝＋０．１° …（７）
このように傾斜角βをやや大きくとることが望ましい。
【００８２】
上記傾斜角βは、作動上からさらに大きく設定したい。しかし、あまり大きく設定すると、内スライド金型１２自体の形状が成り立たなくなってしまう。そこで、次式のように所定の制限をした状態で傾斜角βを傾斜角αやγに対して設定する。すなわち、

とすることが更に望ましい。
【００８３】
ここで、上記内スライド金型１２の上記傾斜角α，β，γの具体的な数値設定について説明する。
上記傾斜角αは、大きくし過ぎるとセンターコア３の先端、すなわち、図７における上側端部が細くなり、センターコア３の強度が不足する。また、逆に傾斜角αを小さくし過ぎた場合には、可動型のストロークの限界を超えて、センターコア移動距離Ｓ（図５）、すなわち、軸方向への移動を大きくしないと、第１スライドコア４の内側への窄み量が不足し、カム溝の型抜けができなくなる。
【００８４】
一方、傾斜角βに関しても傾斜角αと同様であって、大きくし過ぎるとセンターコア３の先端端部（図７における上側端部）が細くなってセンターコア３の強度が弱くなり、傾斜角βを小さくし過ぎると、センターコア移動距離Ｓを大きくしないと第２スライドコア５の内側への窄み量が不足し、同様にカム溝の型抜けができなくなる
また、傾斜角γは、あまり小さく設定すると第１スライドコア４Ａ〜４Ｄの幅端部がナイフエッジ状となり、破損しやすくなる。逆に傾斜角γを大きくし過ぎると、それに伴って傾斜角βも大きくする必要があり、上述した傾斜角βを大きくしたときの問題が発生する。
【００８５】
上述した事情を鑑み、実際に金型を製作し、実験した結果により、上記傾斜角α及び傾斜角γは、以下の範囲の値を採用することが望ましいことが解った。すなわち、
上記傾斜角αは、
１．０°≦α≦４．０° …（９）
望ましくは、
１．５°≦α≦２．５° …（１０）
とする。
【００８６】
また、上記傾斜角γは、
０°≦γ≦３０° …（１１）
望ましくは、
５°≦γ≦２０° …（１２）
とする。
【００８７】
一方、上記傾斜角βに関しては、上記傾斜角α，γを適用した場合、次式により求められる範囲の値を適用することが望ましい。すなわち、
β≧２^１／２×α／（１−ｔａｎγ）＋０．１° …（１３）
更に望ましくは、
２^１／２×α／（１−ｔａｎγ）＋０．１７５°≦β
≦２^１／２×α／（１−ｔａｎγ）＋１．５° …（１４）
とする。この場合、α，βともに数度という小さな値が条件である。
【００８８】
なお、上述した各設定範囲は、実際に金型製作検討して求められたものであるが、特に本実施の形態の内スライド金型１２においては、傾斜角α＝２．０°，傾斜角β＝４．５°，傾斜角γ＝１５．０°を採用している。
【００８９】
次に、本実施形態の内スライド金型１２によるカム枠２のカム溝部の型抜きについて説明する。
前記図１は、カム枠２を第１スライドコア４Ａの型抜き方向から見た断面図であるが２つの型割線２ｄに挟まれた範囲において、カム溝２ｂがアンダーカットとなっている部分はない。すなわち、上記８分割の第１，２スライドコアを有する本実施形態の内スライド金型１２によりカム枠２を成形し、離型することができる。
【００９０】
しかし、従来の技術による６分割のスライドコアを有する金型では、型割線２ｄ′の間が図１に示すようにより幅広になっている。したがって、上記型割線２ｄ′に挟まれた範囲において、カム溝２ｂの端部領域でアンダーカットとなっている。すなわち、上記従来の金型では、本実施形態のカム枠２を成形し、離型することはできない。
【００９１】
図１２は、カム枠において、フランク角θをパラメータにしたときのカム溝の対軸心の傾き（カム溝の軸心に対する傾き）Ｋと、上記フランク角θ（θ１ 、または、θ２ ）のカム溝の型抜きが可能な、すなわち、アンダーカット部分が生じないスライドコアの円弧中心角ω（ω１ 、または、ω２ ）との関係を示す線図である。
【００９２】
上記図１２によれば、たとえば、円弧中心角ω１ ，ω２ が角度６０°で対軸心の傾きＫ＝１．０５のとき、フランク角θ１，θ２が角度２０．０°以上あれば、金型から成形品を離型できることが判る。図１２に示すようにカム溝の対軸心の傾きＫが小さいほど（すなわち、カム溝が回転角に対して急峻であるほど）、また、フランク角θが小さいほど、型抜き可能なスライドコアの円弧中心角ωは、小さくなる。すなわち、型抜き可能なスライドコアの円弧幅が狭く、制限される。
【００９３】
なお、上記カム溝の対軸心の傾きＫは、カム溝の（円周距離Ｇ０ ／軸方向距離Ｚ０ ）で与えられ、上記円周距離Ｇ０ は、カム溝の最大径における円周距離とする。通常、上記傾きＫには、図１２に示す０．６５〜１．２５の範囲が採用される。このＫの値は、上述のように型抜きに大きな影響を与え、特にパーティングライン（型割線）とその近傍において重要となる。
【００９４】
上記従来の６分割スライドコア適用の金型の場合、図１２に示すスライドコアの円弧中心角ωｂがおよそ７０°〜８０°の範囲になる。したがって、カム溝の対軸心の傾きＫにもよるがフランク角θがおよそ２２．５°以上ないと型抜きが難しくなる。
【００９５】
一方、本実施形態の８分割スライドコア適用の内スライド金型１２の場合、図１２に示すスライドコアの円弧中心角ωａがおよそ５５°〜７０°の範囲になる。したがって、カム溝の対軸心の傾きＫにもよるがフランク角θがおよそ１６．５°以上で型抜きが可能となり、カム溝の形状に対する制限が少なくなる。
【００９６】
上述したカム溝の型抜き状態を踏まえて、実験的に金型によるカム枠の成形を行った結果、本実施形態の内スライド金型１２においては、カム溝の本数３、分割数８である場合、上記カム溝のフランク角θ１ ，θ２ 、および、カム溝の傾きＫは、
１６．５°≦θ１ ≦２８．０°
１６．５°≦θ２ ≦２８．０°
０．６５ ≦Ｋ≦１．２５ …（１５）
の各値が適用可能であることが解った。
【００９７】
また、フランク角θ１ ，θ２ の上限を抑えた場合、
１６．５°≦θ１ ≦２７．５°
１６．５°≦θ２ ≦２７．５°
０．７０ ≦Ｋ≦１．２５ …（１６）
の各値を適用可能であることが解った。
【００９８】
さらに、フランク角θ１ ，θ２ の上限を抑えた場合、
１６．５°≦θ１ ≦２６．５°
１６．５°≦θ２ ≦２６．５°
０．８０ ≦Ｋ≦１．２５ …（１７）
の各値を適用可能であることが解った。
【００９９】
なお、上記カム溝の本数及び金型分割数にて、カム溝数が１以上、かつ、分割数が８以上である場合に対しても上記（１５），（１６），（１７）式は、適用可能であり、さらに、上記カム枠のカム溝に換えて筒状部材の内周に設けられる雌ヘリコイドネジにも上記（１５），（１６），（１７）式は、適用可能である。
【０１００】
以上、説明したように本実施の形態の内スライド金型１２は、８分割のスライドコアで型が構成されているため、各スライドコアの円弧中心角ω１ ，ω２ を小さく設定でき、フランク角θ１ ，θ２ が小さいカム溝を形成することが可能で、強度に優れ、カムフォロアがカム溝から外れる等の不具合発生が防止できる鏡枠装置を成形することができる。
【０１０１】
また、カムフォロア１ａ，１ｂ，１ｃの３つに対して、本実施の形態の内スライド金型１２で成形されたカム枠２の型割線２ｄが８箇所存在する。したがって、前記第１実施形態の鏡枠装置１０においては、３つのカムフォロア１ａ，１ｂ，１ｃが型割線１８を同時に通過することがない。従って、鏡枠装置１０のズーム操作中に大きな駆動力を必要とせず、更には撮影画像が揺れたり、描写力が低下するという問題も生じにくくなる。
【０１０２】
さらに、副次的な効果として、カメラのズーム鏡筒に適用される筒状部材として図１３の斜視図に示すような前方側が円筒形状でカメラ本体側端部が四角筒形状の特殊な形状をした鏡枠部材２１が存在するが、その鏡枠部材の成形に本実施の形態の８分割式内スライド金型１２を適用すると、８つのスライドコアを利用するため、鏡枠部材２１の四角筒部分を含めてバランス良く成形することができる。
【０１０３】
上記第２実施形態の内スライド型１２においては、センターコア３に対して第１，２スライドコア４，５がアリ継ぎ係合されているが、この結合構造は、アリ継ぎ係合に限定されるものではなく、例えば、Ｔ溝係合など、２つの部材が摺動可能に係合できる係合手段であれば、様々な係合手段を適用することが可能である。
【０１０４】
また、第２実施形態の内スライド型１２における第２スライドコアの摺動面５ｂ、および、その面に摺接するセンターコアの摺動面３ｄは、それぞれ単一面で形成されているが、これらの面は、複数の面に分かれて形成されていてもよい。また、第１スライドコアの当接摺動面４ｂと、その面に当接するセンターコアの摺動面３ｃおよび第２スライドコアの当接面５ｇとも、複数面に分かれて形成されていてもよい。但し、この場合、傾斜角γは、最も大きい角度を示す部分を指すことになる。
【０１０５】
上記内スライド金型１２は、８分割スライドコアを適用するものであるが、上記８分割に限らず８分割以上の偶数の分割数Ｎのスライドコアをもつ内スライド金型にも同様の構造をを適用することにより同様の効果を得ることができる。この場合、分割数Ｎは、（第１のスライドコアの数ｊ）×２となり、分割角度εは、３６０°／２ｊで与えられる。
【０１０６】
そして、上記Ｎ分割内スライド金型におけるセンターコアおよび第１スライドコア，第２スライドコアの傾斜角度α、β、γは次式の関係であることが必要である。すなわち、ｊ＝Ｎ／２として、
β≧ｔａｎ^−１｛ｔａｎα／｛ｃｏｓ（３６０°／２ｊ）−ｓｉｎ（３６０°／２ｊ）×ｔａｎγ｝｝＋０．１°…（１８）
また、次式の関係であること更に望ましい。すなわち、
ｔａｎ^−１｛ｔａｎα／｛ｃｏｓ（３６０°／２ｊ）−ｓｉｎ（３６０°／２ｊ）×ｔａｎγ｝｝＋０．１７５°≦β
≦ｔａｎ^−１｛ｔａｎα／｛ｃｏｓ（３６０°／２ｊ）−ｓｉｎ（３６０°／２ｊ）×ｔａｎγ｝｝＋１．５°…（１９）
であることが望ましい。
【０１０７】
ここで、分割数Ｎが１０である場合、すなわち、１０分割の内スライド金型の例について説明すると、この１０分割内スライド金型は、１つのセンターコアと、５つの第１スライドコアと、５つの第２スライドコアからなるカム枠を成形する型である。上記第１スライドコアと第２スライドコアはセンターコアの周囲に角度３６°の間隔で交互に配置されている。その他の構成は、前記第２の実施形態の内スライド金型１２と同様とする。
【０１０８】
この１０分割内スライド金型で成形されるカム枠は、その内周に型割線が１０箇所に付いている。また、上記カム枠の内周には、前記第１の実施形態のカム枠１９と同様に、カム枠の内周には同形状のカム溝が内周上、円周方向に略１２０°毎に設けられており、そのカム溝には、移動枠に設けられたカムフォロアが摺動自在に嵌合する。
【０１０９】
上記カム枠を成形後、カム枠を金型から取り出すときは、前記第２の実施形態の内スライド金型１２と同様に第１スライドコア及び第２スライドコアは内側に窄まる。
【０１１０】
上記１０分割内スライド金型のセンターコアや第１，２スライドコアの傾斜角度α、β、γは、次式の関係であることが必要である。すなわち、
β≧ｔａｎ^−１｛ｔａｎα／（ｃｏｓ３６°−ｓｉｎ３６°×ｔａｎγ）｝＋０．１° …（２０）
であることが必要である。
【０１１１】
さらに、次式の関係を満足することが望ましい。すなわち、
ｔａｎ^−１｛ｔａｎα／（ｃｏｓ３６°−ｓｉｎ３６°×ｔａｎγ）｝＋０．１７５°≦β
≦ｔａｎ^−１｛ｔａｎα／（ｃｏｓ３６°−ｓｉｎ３６°×ｔａｎγ）｝＋１．５° …（２１）
であることが望ましい。
【０１１２】
上記１０分割内スライド金型を適用する場合、前記第２実施形態の内スライド金型１２よりも、各スライドコアの円弧中心角ωが更に小さくなり、略台形をしたカム溝断面の中心から、カム枠の中心軸へ垂直に延ばした直線とカム溝の各壁がなす角度θ１ またはθ２ を更に小さくすることが可能で、更に強度に優れるカム枠を成形することができる。
【０１１３】
また、カムフォロアピンが３つに対して、型割線が１０箇所あるため、同時に３つのカムピンが型割線を通過することが無い。従って、ズーム操作中に大きな駆動力を必要とせず、更に撮影画像が揺れたり、描写力が低下するという問題も生じにくくなる。
【０１１４】
次に、上記内スライド金型１２により成形可能なカム枠のカム溝の変形例として、図１４（Ａ），（Ｂ）の断面図に示す形状のカム溝を提案できる。
【０１１５】
図１４（Ａ）に示す変形例のカム枠２２のカム溝２２ａは、内側面が曲面により形成されるカム溝である。上記カム溝２２ａに摺動自在に嵌入される移動枠２３のカムフォロア２３ａは、上記カム溝２２ａの断面形状に合致した球面状先端部を有するカムフォロアである。
【０１１６】
また、図１４（Ｂ）に示す変形例のカム枠２４のカム溝２４ａは、溝の底部にさらなる傾斜面が設けられた形状を有している。上記カム溝２４ａに摺動自在に嵌入される移動枠２５のカムフォロア２５ａは、上記カム溝２４ａの断面形状に合致させ、面取り形状先端部を有するカムフォロアである。
【０１１７】
本変形例においては、、これらのカム溝２２ａ，２４ａも略台形形状のカム溝として扱うこととし、上記図１４（Ａ），（Ｂ）に示したカム溝２２ａ，２４ａにおけるフランク角θ１ ，θ２ は、略台形をしたカム溝断面の中心からカム枠の中心軸へ垂直に延ばした直線と、上記カム溝の側壁とがなす角度のそれぞれ最も小さくなる部分を指すこととする。そして、上述した内スライド金型におけるセンターコアやスライドコアの傾斜角α，β，γは、前述した各演算式を用いて求めることができる。
【０１１８】
次に、本発明の第３の実施形態の筒状部材装置である鏡枠装置について図１５を用いて説明する。
上記図１５は、上記鏡枠装置の鏡枠を内周側から見た展開図である。
【０１１９】
本実施形態の鏡枠装置は、カメラのズームレンズ鏡筒に適用されるものであり、主にヘリコイド枠３１と移動枠３２とを有してなる。上記ヘリコイド枠３１は、前記第２の実施形態の金型装置１１と略同様の構成の金型により成形が可能な筒状部材である。
【０１２０】
上記ヘリコイド枠３１には、内周面に２条ずつ１２０°間隔で３箇所に案内部である雌ヘリコイドネジ３１ａ，３１ｂ，３１ｃが設けられている。
【０１２１】
移動枠３２には、外周面に２条ずつ１２０°間隔で３箇所に被案内部である雄ヘリコイドネジ３２ａ，３２ｂ，３２ｃが設けられている（図１５中、破線で示される）。この移動枠３２は、上記ヘリコイド枠３１の内周に雌ヘリコイドネジ３１ａ，３１ｂ，３１ｃに雄ヘリコイドネジ３２ａ，３２ｂ，３２ｃを螺合させた状態で嵌入し、さらに、図示しない固定部により回転規制状態で支持されている。
【０１２２】
上記鏡枠装置においては、ヘリコイド枠３１が回転駆動されると、上記ヘリコイドネジを介して移動枠３２が軸方向Ｃに沿って進退移動する。
【０１２３】
上記ヘリコイド枠３１は、前記第２実施形態に示した内スライド金型１２のカム溝を形成するための凸部４ｆ，５ｆを雌ヘリコイドネジ形成用のヘリコイド凸部に代えたヘリコイド用内スライド金型により成形することができる。
【０１２４】
このヘリコイド用内スライド金型においても前記内スライド金型１２と同様にセンターコアやスライドコアの傾斜角α，β，γは、前述した各演算式を用いて求めることができる。
【０１２５】
上記ヘリコイド用内スライド金型により成形されたヘリコイド枠３１の内周面には、図１５に示すように８本の型割線３１ｄが付く。ヘリコイド枠３１を回動駆動させた場合、移動枠３２のある２条の雄ヘリコイドネジ３２ａ，３２ｂ，３２ｃの何れかがヘリコイド枠３１の型割線３１ｄ上にあっても、それ以外の雄ヘリコイドネジのうち少なくとも１条は、型割線３１ｄ上に位置しない。
【０１２６】
本実施形態の鏡枠装置によれば、ヘリコイド枠３１が前記第１実施の形態におけるカム枠２と同等に、カム溝１５のフランク角θ１ ，θ２ に相当する雌ヘリコイドネジ３２ａ，３２ｂ，３２ｃのフランク角の傾斜角が小さかったとしても成形および離型が可能で、強度に優れるズーム枠を得ることができる。また、上述したようにある２条の雄ヘリコイドネジがヘリコイド枠３２の型割線３１ｄ上にあっても、他の雄ヘリコイドネジのうち少なくとも１条は、型割線３１ｄ上に位置しないため、ズーム操作中に大きな駆動力を必要とせず、さらには撮影画像が揺れたり、描写力が低下するという問題も生じにくくなる。
次に、本発明の第４の実施形態であるの筒状部材装置である鏡枠装置について図１６を用いて説明する。
上記図１６は、上記鏡枠装置の鏡枠を内周側から見た展開図である。
【０１２７】
本実施形態の鏡枠装置は、カメラのレンズ鏡筒の一部に適用されるものであり、主に固定枠４１と回転枠４２とを有してなる。上記固定枠４１は、前記第２の実施形態の金型装置１１と略同様の構成の金型により成形が可能な筒状部材である。
【０１２８】
上記固定枠４１には、内周面に周方向に沿った１本の案内部であるガイド溝４１ｂが設けられ、さらに、上記ガイド溝４１ｂに通ずる３つの突起挿入口４１ａが設けられている。
【０１２９】
回転枠４２には、外周面に３つの被案内部である突起４２ａが設けられている（図１６中、破線で示される）。この回転枠４２は、上記突起挿入口４１ａを通して突起４２ａを固定枠４１の内周に挿入し、ガイド溝４１ｂに摺動自在に嵌入させて組み込まれ、固定枠４１に対して軸方向Ｃの移動が規制された状態で回転可能に支持される。
【０１３０】
上記固定枠４１は、前記第２実施形態に示した内スライド金型１２のカム溝を形成するための凸部４ｆ，５ｆを円周方向に沿った凸部に代えた内スライド金型により成形することができる。
【０１３１】
上記内スライド金型においても前記内スライド金型１２と同様にセンターコアやスライドコアの傾斜角α，β，γは、前述した各演算式を用いて求めることができる。この内スライド金型により成形された固定枠４１には、図１６のように８本の型割線４１ｄが付く。そのため、周方向に等間隔に配される回転枠４２の３つの突起４２ａの１つが型割線４１ｄ上に位置したとしても他の突起４２ａのうち少なくとも１つは、型割線４１ｄ上に位置しない。
【０１３２】
したがって、本実施形態の鏡枠装置によれば、鏡枠回転操作中に大きく変動するような駆動力を必要とせず、スムーズが回転状態が得られる。
【０１３３】
なお、上記固定枠４１のガイド溝４１ｂが凸状の周方向に沿ったガイド部であって、回転枠４２の突起２ａを凹状部とする鏡枠装置においても同様の効果を奏する。
【０１３４】
次に、本発明の第５の実施形態であるの筒状部材装置である鏡枠装置について図１７を用いて説明する。
上記図１７は、上記鏡枠装置の鏡枠を内周側から見た展開図である。
【０１３５】
本実施形態の鏡枠装置は、カメラのレンズ鏡筒の一部に適用されるものであり、主にカム枠４５と移動枠４６とを有してなる。
【０１３６】
上記カム枠４５は、前記第２の実施形態の金型装置１１の分割数を６分割とした金型装置により成形可能なものであり、内周に設けられる案内部のカム溝の本数が４本である枠である。すなわち、上記カム枠４５には、内周面に４本のカム溝４５ａ，４５ｂ，４５ｃ，４５ｄが円周方向に９０°毎等間隔に配置されている。
【０１３７】
上記移動枠４６には、外周面に４つの被案内部のカムフォロア４６ａ，４６ｂ，４６ｃ，４６ｄが円周方向に９０°毎等間隔に配置されている。この移動枠４６は、カム枠４５の上記各カム溝に上記各カムフォロアを摺動自在に嵌入してカム枠４５内に組み込まれる。
【０１３８】
本鏡枠装置においては、カム枠４５が回転駆動されると、移動枠４６が上記カム溝を介して軸方向Ｃに進退駆動される。
【０１３９】
上記カム枠４５を成形するには、前記第２実施形態に示した内スライド金型１２のカム溝を形成するための凸部の本数を４本とし、スライドコアの分割数を６分割とした内スライド金型を適用する。
【０１４０】
この内スライド金型においても前記内スライド金型１２と同様にセンターコアやスライドコアの傾斜角α，β，γは、前述した各演算式を用いて求めることができる。但し、スライドコアの数２ｊを６とする。
【０１４１】
上記内スライド金型により成形されたカム枠４５には、図１７のように従来の６分割内スライド金型と同様に６本の型割線４５ｄが付く。しかし、カム溝が４本、カムフォロア４６ａ，４６ｂ，４６ｃ，４６ｄが４つであり、上記金型の分割数６と整数倍の関係にないので、移動枠４６の４つのカムフォロア４６ａ，４６ｂ，４６ｃ，４６ｄの１つが型割線４５ｄ上に位置したとしても他のカムフォロア４６ａ，４６ｂ，４６ｃ，４６ｄのうち少なくとも１つは、型割線４５ｄ上に位置しない。
【０１４２】
したがって、本実施形態の鏡枠装置によれば、カム枠回転中に大きく変動するような駆動力を必要とせず、スムーズが移動枠の進退駆動状態が得られる。
【０１４３】
次に、本発明の第６の実施形態である金型装置の内スライド金型について図１８の上記内スライド金型の斜視図を用いて説明する。
図１８に示すように本実施形態の内スライド金型５１は、スライドコアガイド用のアリ部を持たない８分割スライド金型であって、センターコア５２と、センターコア５２の周囲に角度４５°間隔で交互に配される４つの第１スライドコア５３Ａ，５３Ｂ，５３Ｃ，５３Ｄおよび４つの第１スライドコア５４Ａ，５４Ｂ，５４Ｃ，５４Ｄと、軸心Ｃ０ に対し僅かに傾斜した各４本の第１，２アンギュラピン５５，５６とを有してなる。この内スライド金型５１は、図示しない可動型に組み込まれ、型締め位置と型開き位置とに駆動され、内周カム溝を有する筒状部材のカム枠を射出成形するための金型である。
【０１４４】
上記第１スライドコア５３Ａ，５３Ｂ，５３Ｃ，５３Ｄは、それぞれ同一形状を有し、上記第２スライドコア５４Ａ，５４Ｂ，５４Ｃ，５４Ｄもそれぞれ同一形状を有しているので、その中の１組の第１スライドコア５３Ａと第２スライドコア５４Ａの形状についてのみ説明する。
【０１４５】
上記第１スライドコア５３Ａは、軸心Ｃ０ を中心とする円筒面の一部であって、カム枠の内周面を形成するための円筒面５３ａと、円筒面５３ａ上に設けられ、カム枠のカム溝を形成するための凸部５３ｂと、内周側の突起５３ｆと、円筒面５３ａの両内側に設けられ、軸心Ｃ０ 方向に沿った所定の開き角を有する傾斜面の当接面５３ｇと、コア受け端部側にて軸心Ｃ０ の半径方向に延出して形成されるスライドガイド部５３ｄと、上記スライドガイド部５３ｄ上に設けられ、所定角αだけ軸心Ｃ０ 側に傾斜するアンギュラピン穴５３ｅとを有している。この第１スライドコア５３Ａは、図示しない可動型の内スライド受けに径方向に摺動自在に支持されている。
【０１４６】
上記第２スライドコア５４Ａは、軸心Ｃ０ を中心とする円筒面の一部であって、カム枠の内周面を形成するための円筒面５４ａと、円筒面５４ａ上に設けられ、カム枠のカム溝を形成するための凸部５４ｂと、内周側の突起５４ｆと、円筒面５４ａの両外側にて軸心Ｃ０ 方向に沿った所定の開き角を有する当接面５４ｇと、コア受け端部側にて軸心Ｃ０ の半径方向に延出して形成されるスライドガイド部５４ｄと、上記スライドガイド５４ｄ上に設けられ、軸心Ｃ０ に対して所定角βだけ軸心Ｃ０ 側に傾斜するアンギュラピン穴５４ｅとを有している。この第２スライドコア５４Ａは、上記図示しない可動型の内スライド受けに径方向に摺動自在に支持されている。
【０１４７】
なお、上記当接面５３ｇは、軸心Ｃ０ と直交する平面上にて、軸心Ｃ０ および第１スライドコア中心を含む平面に直交する方向となす角が傾斜角γとなる傾斜面である。また、上記当接面５４ｇは、上記第１スライドコア５３の当接面５３ｇと型締め時に密着する面であり、軸心Ｃ０ と直交する平面上にて、軸心Ｃ０ および第２スライドコア中心を含む平面に直交する方向となす角が傾斜角（γ＋４５°）となる傾斜面である。
【０１４８】
また、上記凸部５３ｂ、または、５４ｂは、第１スライドコアの円筒面５３ａと第２スライドコアの円筒面５４ａとの間を少なくとも一箇所を跨いで分断されていて、連続的に連なって形成されるものとする。
【０１４９】
上記センターコア５２は、軸心Ｃ０ に沿ったテーパ形状となっており、その端部は、可動型のセンターコア受け部（図示せず）に固定されている。センターコア５２には、型締め状態では、第１，２スライドコア５３Ａ，５４Ａ等の突起５３ｆ，５４ｆが当接している。型開き時に第１，２スライドコア５３Ａ，５４Ａ等の突起５３ｆ，５４ｆが内側方向に移動してくるが、上記センターコア５２は、軸心Ｃ０ 方向への移動により上記突起５３ｆ，５４ｆと軸心Ｃ０ 方向に摺接する。
【０１５０】
上記第１アンギュラピン５５は、上端側が傾斜角αだけ軸心Ｃ０ 側に傾斜した状態で可動型のセンターコア受け部（図示せず）に固定されている。そして、第１スライドコア５３Ａ等のアンギュラピン穴５３ｅに摺動自在に嵌入している。
【０１５１】
上記第２アンギュラピン５６は、上端側が傾斜角βだけ軸心Ｃ０ 側に傾斜した状態で可動型のセンターコア受け部（図示せず）に固定されている。そして、第２スライドコア５４Ａ等のアンギュラピン穴５４ｅに摺動自在に嵌入している。
【０１５２】
上記第１，２アンギュラピン５５，５６は、型開き時に上記センターコア５２とともにセンターコア受け部側に後退するので、上記アンギュラピン穴５３ｅ，５４ｅを介して第１，２スライドコア５３Ａ，５４Ａが軸心側に向けて窄まるようにスライド移動してゆく。
【０１５３】
上述した構成を有する内スライド金型５１を適用した金型装置においては、型締め状態では、上記第１スライドコア５３Ａ等の当接面５３ｇの内側に上記第２スライドコア５４Ａ等の当接面５４ｇが密着して当接している。
【０１５４】
樹脂注入射出後の型開き時にセンターコア５２がセンターコア受け方向に所定量移動すると、傾斜している第１，２アンギュラピン５５，５６にガイドされて第１，２スライドコア５３Ａ，５４Ａ等が内側に所定量だけスライド移動して窄まった状態となる。上記第１，２スライドコア５３Ａ，５４Ａ等の移動によって第１，２スライドコアの凸部５３ｂ，５４ｂが成形されたカム枠のカム溝から離れ、上記カム枠が型抜き可能となる。
【０１５５】
なお、上記内スライド金型５１により成形されたカム枠には、やはり８本の型割線が残るがそれらの線は、この実施形態においては、互いに平行な線である。
【０１５６】
上述したように金型装置５１の型開きにより、第１スライドコア５３Ａ等と第２スライドコア５４Ａ等を互いに軸心Ｃ０ に向けてカム枠２が取り出し可能な状態となるように少なくともカム溝の深さ分は、窄ませる必要がある。そのとき、第１スライドコア５３Ａ等の当接面５３ｇとその内側にある第２スライドコア５４Ａ等の当接面５４ｇが干渉しないように、第１スライドコア５３Ａ等のスライド量よりも第２スライドコア５４Ａ等のスライド量を所定量多くとる。このスライド量は、上記アンギュラピンの傾斜角α，βやスライドコアの当接面の傾斜角γなどにより決定される。
【０１５７】
本実施形態の内スライド金型５１における上記傾斜角α，β、および、傾斜角γは、前記第２の実施形態の８分割内スライド金型１２の場合と同様に前記演算式（７），（８）等を適用して求めることができる。
【０１５８】
本実施形態に内スライド金型５１によると、前記第２実施形態の内スライド金型１２の場合と同様の効果を得ることができる。すなわち、上記内スライド金型５１で成形されたカム枠は、カム溝のフランク角θ１ ，θ２ が小さく、カムフォロアがはずれにくい強度的に優れたものである。また、上記カム枠には、３つのカムフォロアに対して、型割線は、８箇所であるため、同時に３つのカムフォロアが型割線を通過することが無い。従って、カム枠操作中に大きな駆動力を必要としない。上記カム枠がカメラの鏡枠に適用された場合、撮影画像が揺れたり、描写力が低下するという問題も生じにくくなる。
【０１５９】
また、本実施形態の内スライド金型５１の場合、アリ溝構造を採用する必要がないので金型製作が容易になり、金型の製作コスト低減や製作期間の短縮等が実現できる。
【０１６０】
以上、説明した各実施形態に示したカム枠やヘリコイド枠等の筒状部材を成形するための成形手段は、上記実施形態に限定されるものではなく、プラスチック射出成形のほか、金属粉末射出成形、金属ダイカスト、セラミック成形等、その他、様々な成形材料による成形手段に適用することが可能である。
【０１６１】
また、上述した各実施形態に示したカム枠やヘリコイド枠等の筒状部材では溝部の一方のフランク角θ１ と他方のフランク角θ２ とは、等しいとしたが、これに限らずフランク角θ１ とθ２ とが異なる角度をもつ溝部、または、凸部を有する筒状部材の成形にも適用可能である。更に、単一の筒状部材にカム溝、ヘリコイドネジ、横溝などが２つまたは３つ複合して設けられている場合にも、本発明による金型による成形は可能である。
【０１６２】
また、上記各実施形態の金型で成形された筒状部材の型割線は、カム枠やヘリコイド枠の一方の端から他方の端まで付いてたが、このような筒状部材に限定するものではなく、たとえば、型割線が筒状部材の端面まで達していないような場合にも本発明による金型は、適用可能である。
【０１６３】
また、上記各実施形態の金型で成形された筒状部材のカム溝や横溝（周方向溝）は、筒状部材の内周面に対して凹んでいるものであったが、本発明による筒状部材は、これに限定するわけではなく、凸形状のカムや周方向凸部を有する筒状部材にも適用可能である。
【０１６４】
さらに、上記各実施形態やその変形例における筒状部材は、カメラのレンズ鏡筒を例に挙げたが、本発明の要旨は、上記カメラのレンズ鏡筒以外、例えば、口紅の容器、瓶等のキャップ、その他、成形アンダーカットのある様々な機構部品の成形にも適用可能である。
【０１６５】
また、上記各実施形態における金型を構成する部材は、その材質を鉄鋼やアルミニウム合金などの金属に限定するものでなく、例えば、セラミック，樹脂，樹脂と金属粉末の複合材、その他の材質を用いることができる。
【０１６６】
【発明の効果】
本発明の１つによれば、嵌合部の少なくとも１箇所は型割線上に位置しない。そのため、がたつきが小さく、また、カメラに適用された場合、撮影している画像の揺れのた発生や描写力の低下を抑えることができる筒状部材、または、筒状部材装置を提供することができる。
【０１６７】
本発明の他の１つによれば、形成されたカム溝またはヘリコイドネジ等のフランク角が小さく、外力による嵌合部の外れが発生しにくく、強度の強い筒状部材、または、筒状部材装置を提供することができる。
【０１６８】
本発明のさらに他の１つによれば、嵌合部の少なくとも１箇所は型割線上に位置しない。そのため、がたつきが小さい筒状部材を成形可能な金型を提供することができる。
【０１６９】
本発明のまたさらに他の１つによれば、形成されたカム溝またはヘリコイドネジ等のフランク角が小さく、外力による嵌合部の外れが発生しにくい筒状部材を成形することが可能な金型を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態の鏡枠装置の縦断面図である。
【図２】上記図１の鏡枠装置のカム枠のカム溝の溝直角断面図である。
【図３】上記図１の鏡枠装置を内周側から見た展開図である。
【図４】上記第２の実施形態の金型装置の型締め状態での縦断面図である。
【図５】上記図４の金型装置の型開き状態での縦断面図である。
【図６】上記図４の金型装置の内スライド金型を軸方向から見た平面図である。
【図７】図６のＡ−Ａ断面図である。
【図８】上記図４の金型装置の第１，２スライドコアの斜視図であって、図８（Ａ）は、第２のスライドコアの斜視図で、図８（Ｂ）は、第１のスライドコアの斜視図である。
【図９】上記図４の金型装置の内スライド金型のセンターコアの斜視図である。
【図１０】上記図４の金型装置の相隣る第１，２のスライドコアの移動状態を軸方向から見た図であって、型締め状態の位置と、型開き状態のスライド位置とを示す。
【図１１】上記図１０のスライドコアの部分拡大図である。
【図１２】上記図４の金型装置、または、従来の金型装置で成形されるカム枠において、フランク角θをパラメータにしたときのカム溝の対軸心の傾きＫと、上記フランク角θのカム溝の型抜きが可能なスライドコアの円弧中心角ωとの関係を示す線図である。なお、ωａは、ｊ＝４のとき、可能な範囲、ωｂは、ｊ＝３のとき、可能な範囲である。
【図１３】上記図４の金型装置により成形される他の例の筒状部材の斜視図である。
【図１４】上記図４の金型装置により成形可能なカム枠のカム溝と、該カム溝に嵌入するカムフォロアの変形例を示す断面図であり、図１４（Ａ）は、上記変形例の１つを示し、図１４（Ｂ）は、上記変形例の他の１つを示す。
【図１５】本発明の第３の実施形態の筒状部材装置である鏡枠装置を内周側から見た展開図である。
【図１６】本発明の第４の実施形態の筒状部材装置である鏡枠装置を内周側から見た展開図である。
【図１７】本発明の第５の実施形態の筒状部材装置である鏡枠装置を内周側から見た展開図である。
【図１８】本発明の第６の実施形態の金型装置の内スライド金型の斜視図である。
【図１９】従来の鏡枠装置の斜視図である。
【図２０】上記図１９の従来の鏡枠装置の内周面の展開図である。
【図２１】上記図１９の従来の鏡枠装置のカム枠に設けられるカム溝とカムフォロアの拡大断面図である。
【符号の説明】
１，３２，４５…移動枠（第２の筒状部材）
１ａ，１ｂ，１ｃ…カムフォロア（被案内部）
２，４５…カム枠（第１の筒状部材，筒状部材）
２ａ，２ｂ，２ｃ…カム溝（案内部）
２ｄ，３１ｄ，４１ｄ，４５ｄ…型割線
３，５２…センターコア
４Ａ，４Ｂ，４Ｃ，４Ｄ，５３Ａ，５３Ｂ，５３Ｃ，５３Ｄ…第１のスライドコア
４ｂ…摺動当接面（傾斜面）
４ｆ，５ｆ，５３ｂ，５４ｂ…凸部
５Ａ，５Ｂ，５Ｃ，５Ｄ，５４Ａ，５４Ｂ，５４Ｃ，５４Ｄ…第２のスライドコア
３１ …ヘリコイド枠（第１の筒状部材，筒状部材）
３１ａ，３１ｂ，３１ｃ…雌ヘリコイドネジ（案内部）
３２ …移動枠（第２の筒状部材，筒状部材）
３２ａ，３２ｂ，３２ｃ…雄ヘリコイド（被案内部）
４１ …固定枠（筒状部材）
４１ｂ…ガイド溝（円周方向溝）
４２ …回転枠（筒状部材）
４２ａ…突起（凸部）
５３ｇ…当接面（傾斜面）
α …傾斜角（角度）
β …傾斜角（角度）
γ …傾斜角
Ｃ０ …センターコア軸心
θ１ ，θ２ …フランク角
Ｋ …カム溝の筒部材の軸方向に対する傾き[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tubular member, a tubular member device incorporating the tubular member, and a mold for molding the tubular member.
[0002]
[Prior art]
As a conventional cylindrical member device, for example, a cylindrical member which is applied to a zoom lens barrel of a camera, has an undercut portion such as a cam groove or a screw on an inner surface, and is formed by a mold. There is a mirror frame device to which is applied.
[0003]
As an example of the above-described conventional lens frame device, a structure of the lens frame device shown in a perspective view (shown in partial cross section) of FIG. 19 and a development view seen from the inner periphery of FIG. 20 will be described. The lens frame device includes a rotatably driven cam frame 101 and a movable frame 102 that can move forward and backward. A cam groove 101a having the same shape is formed on the inner peripheral surface of the cam frame 101 in the circumferential direction. Three are provided at intervals of °. On the outer periphery of the moving frame 102, three cam pins 102a are fixedly provided at 120 ° intervals in the circumferential direction. A cam pin 102a is slidably fitted in each cam groove 101a, and the movable frame 102 is driven forward and backward along the axial direction (optical axis) C in FIG. 19 by rotating the cam frame 101. You. Here, a description of a mechanism for moving the moving frame 102 straight will be omitted.
[0004]
The cam frame 101 is provided with a cam groove 101a along the inner peripheral surface thereof as shown in a sectional view of a cam groove in FIG. 21 (a sectional view taken along the line QQ in FIG. 20). It is molded by an injection mold having the following. As the injection mold to be applied, for example, the one described in Patent Document 1 can be applied.
[0005]
The mold for injection molding described in Patent Document 1 has a center core and a slide core divided into six as a core side molding part. The slide core is a six-divided slide core including three first slide cores and three second slide cores alternately arranged around the center core. Guide means (ant, dovetail) for guiding and sliding along the mold opening direction is provided between the center core and the first slide core and between the center core and the second slide core. An injection molding die in which the guide means is provided at substantially the center of each sliding surface of the first slide core and the second slide core and engaged therewith.
[0006]
When the cam frame 101 is formed by the injection mold, the cam groove 101a has a substantially trapezoidal cross section so that the cam groove 101a can be removed from the mold (FIG. 21). A side surface angle (flank angle) formed by a straight line extending perpendicularly from the center to the center axis of the cam frame 101 is a slope having θ1 and θ2. On the other hand, the cam pin 102a slidably fitted into the cam groove 101a has a substantially truncated cone shape. In addition, as shown in FIG. 20, on the inner peripheral surface of the formed cam frame 101, there are six parting lines 101d of the slide cores constituting the mold at six places.
[0007]
In addition, Patent Documents 2, 3, and 4 also propose a mold for injection molding to which the above-described 6,8-divided slide core is applied.
[0008]
[Patent Document 1]
Patent Literature 1 is Japanese Patent Laid-Open Publication No. 2001-170976.
[0009]
[Patent Document 2]
Patent Document 2 is Japanese Patent Laid-Open Publication No. 2000-254947.
[0010]
[Patent Document 3]
Patent Literature 3 is Japanese Patent Laid-Open Publication No. 2000-289062.
[0011]
[Patent Document 4]
Patent Literature 2 is Japanese Patent Laid-Open Publication No. Hei 241886.
[0012]
[Problems to be solved by the invention]
However, in the cam frame 101 formed by the injection molding die to which the six-divided slide core described in Patent Document 1 is applied, the side angles θ1 and θ2 of the cam groove 101a must be set large, and the moving frame 102 When an excessive external force is applied to the cam groove 102, there is a possibility that a problem that the cam pin 102a is easily detached from the cam groove 101a may occur.
[0013]
Further, since the cross section of the cam groove 101a of the cam frame 101 is substantially trapezoidal, if the inner peripheral dimension of the cam frame 101 is deviated from a predetermined value or the roundness of the inner periphery is poor, the apparent cam groove This is the same state as the state where the width of 101a is relatively widened or narrowed. Therefore, when the side angles θ1 and θ2 of the cam groove 101a are large, there is a problem that the positioning accuracy of the moving frame 102 is likely to be deteriorated.
[0014]
From the above, it can be said that it is desirable to minimize the side surface angles θ1 and θ2 of the cam groove 101a of the cam frame 101 from the viewpoint of the product function as the cam frame.
[0015]
Further, minute burrs and steps are generated on the parting line 101d generated by molding. When the moving frame 102 is driven forward and backward by the zoom operation, the cam pin 102a passes through the parting line 101d of the cam groove 101a. In the mold to which the six-part slide core described in Patent Document 1 is applied, assuming that three cam grooves 101a are arranged at equal intervals, three cam pins 102a are used as the cams at the site where the parting line 101d exists. It passes through the groove 101a at the same time. At that time, there is a possibility that a large driving force is required for the zoom operation, or an image captured by the camera is shaken due to rattling, and various problems such as a reduction in depiction power are caused. Even when applied to a cylindrical member other than optical equipment such as a camera, a large driving force is required for operation, which may cause problems in forward / backward driving and the above-mentioned rattling may impair luxury. There was also nature.
[0016]
The present invention has been made in order to solve the above-described problems, and has a good driving performance and a cylindrical member having stable characteristics against external force, or the cylindrical member is applied. It is another object to provide a cylindrical member device that performs the above-described operation, and to provide a mold for molding the cylindrical member.
[0017]
[Means for Solving the Problems]
The cylindrical member according to claim 1 of the present invention is a cylindrical member formed by a mold, wherein N molds are disposed on an inner peripheral surface of the cylindrical member along the axial direction of the cylindrical member in the circumferential direction. It has a parting line and M guide parts each arranged at least in one of the parting lines in the circumferential direction thereof, and N is 8 or more and M is 3 or more.
[0018]
The cylindrical member according to claim 2 of the present invention is a cylindrical member having a guide portion, wherein the guide portion is the cam groove or a female helicoid screw, and one flank angle of the flank surface is θ1 and the other is flank angle. Let the flank angle of θ2 be θ2 and the inclination of the cam groove or female helicoid screw with respect to the axial direction of the cylindrical member be K,
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25
And the guide portion.
[0019]
The cylindrical member according to claim 3 of the present invention is a cylindrical member having a guide portion, wherein the guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is θ1, and the other is a flank angle of θ1. Assuming that the flank angle is θ2 and the inclination of the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 27.5 ° or 16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
And the guide portion.
[0020]
The tubular member according to claim 4 of the present invention is a tubular member having a guide portion, wherein the guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is θ1, and the other is a flank angle. Assuming that the flank angle is θ2 and the inclination of the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 26.5 ° or 16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
And the guide portion.
[0021]
The cylindrical member according to claim 5 of the present invention is a cylindrical member formed by a mold, wherein N molds are disposed on an inner peripheral surface of the cylindrical member in a circumferential direction along an axial direction of the cylindrical member. Having a score line and at least one or more guides,
N ≧ 8
It is.
[0022]
The cylindrical member according to claim 6 of the present invention is the cylindrical member according to claim 5, wherein the guide portion is a cam groove or a female helicoid screw, and one of the flank surfaces has a flank angle of θ1 and the other has a flank angle of θ1. Assuming that the flank angle is θ2 and the inclination of the cam groove with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25,
And the guide portion.
[0023]
The cylindrical member according to claim 7 of the present invention is the cylindrical member according to claim 5, wherein the guide portion is a cam groove or a female helicoid screw, and one of the flank surfaces has a flank angle of θ1 and the other has a flank angle of θ1. Assuming that the flank angle is θ2 and the inclination of the cam groove with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 27.5 ° or 16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
And the guide portion.
[0024]
The cylindrical member according to claim 8 of the present invention is the cylindrical member according to claim 5, wherein the guide portion is a cam groove or a female helicoid screw, and one of the flank surfaces has a flank angle of θ1 and the other has a flank angle of θ1. When the flank angle is θ2 and the inclination of the cam groove with respect to a line orthogonal to the longitudinal direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 26.5 ° or 16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
And the guide portion.
[0025]
The tubular member device according to claim 9 of the present invention is a tubular member device having a tubular member, wherein N pieces are formed by a mold, and are arranged on the inner peripheral surface along the axial direction in the circumferential direction. And a first tubular member having at least one of them and straddling at least one of the parting lines, and having M guide portions arranged in a circumferential direction of the first tubular member. And a second cylindrical member having a guided portion which is equally spaced in the circumferential direction of the outer peripheral surface and which is fitted and slidably contacted with each of the guide portions, wherein N is 8 As described above, M is 3 or more.
[0026]
The cylindrical member device according to a tenth aspect of the present invention is the cylindrical member device according to the ninth aspect, wherein the guide portion is any one of a cam groove, a female helicoid screw, a circumferential groove, and a circumferential rib. The guided part is any one of a cam fore, a male helicoid screw, a circumferential projection, and a circumferential groove so as to correspond to the guide part.
[0027]
The cylindrical member device according to claim 11 of the present invention is the cylindrical member device according to claim 9, wherein N is 8 and M is 3.
[0028]
According to a twelfth aspect of the present invention, in the cylindrical member apparatus according to the ninth aspect, the guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is set to θ1. When the other flank angle is θ2 and the inclination of the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25
And the guide portion.
[0029]
According to a thirteenth aspect of the present invention, in the cylindrical member device according to the ninth aspect, the guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is set to θ1. When the other flank angle is θ2 and the inclination of the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 27.5 ° or 16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
And the guide portion.
[0030]
According to a fourteenth aspect of the present invention, in the cylindrical member device according to the ninth aspect, the guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is θ1 and the other is a flank angle. Assuming that the flank angle is θ2 and the inclination of the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member is K,
16.5 ° ≦ θ1 ≦ 26.5 ° or 16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
And the guide portion.
[0031]
In the mold according to the fifteenth aspect of the present invention, the inner peripheral surface has an even number of parting lines arranged in the circumferential direction along the axial direction, and a guide portion (cam groove) straddling at least one of the parting lines. A mold for molding a cylindrical member having a center core and a center core, the center core being relatively movable in the direction of an angle α with respect to the axis center of the center core and in the radial direction thereof; J first slide cores spaced apart from each other along the circumferential direction of the outer periphery of the core, and relatively moved in the direction of an angle β with respect to the axis center of the center core and in the radial direction with respect to the axis center The same number of second slide cores as the first slide cores are arranged between the first slide cores along the outer periphery of the center core, and the second slide cores are closed when the mold is closed. A first slide core and the second slide core And the inclined surface which separates the first slide core and the second slide core when the mold is opened, in a plane orthogonal to the center axis of the center core. And a contact surface that intersects a line perpendicular to the center line of the first slide core, which intersects the center axis of the center core, at an inclination angle γ, and the angle α, β, γ, j Relationship
β ≧ tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.1 °
And,
j ≧ 4
It is.
[0032]
The mold according to claim 16 of the present invention is the mold according to claim 15, wherein the relationship between the angles α, β, and γ is:
tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.175 ° ≦ β ≦ tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 1.5 °
It is.
[0033]
The mold according to claim 17 of the present invention is the mold according to claim 15, wherein the angle α is
1.0 ° ≦ α ≦ 4.0 °
It is.
[0034]
The mold according to claim 18 of the present invention is the mold according to claim 15, wherein the angle α is
1.5 ° ≦ α ≦ 2.5 °
It is.
[0035]
The mold according to claim 19 of the present invention is the mold according to claim 15, wherein the angle γ is:
0 ° ≦ γ ≦ 30 °
It is.
[0036]
The mold according to claim 20 of the present invention is the mold according to claim 15, wherein the angle γ is:
5 ° ≦ γ ≦ 20 °
It is.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a lens barrel device as a tubular member device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a cam groove of a cam frame, which is a tubular member constituting the lens frame device, taken at right angles to the groove. FIG. 3 is a development view when the lens barrel device is viewed from the inner peripheral side.
[0038]
The lens frame device 10 of the present embodiment is, for example, a lens frame device applicable to a lens barrel of a camera, and mainly includes a moving frame 1 that is a first cylindrical member and a second cylindrical member. And a certain cam frame 2.
[0039]
The moving frame 1 has three guided portions, that is, cam followers 1a, 1b, and 1c arranged at equal intervals (120 ° intervals) in a circumferential direction on an outer peripheral portion thereof. To be able to go back and forth.
[0040]
The cam frame 2 has cam grooves 2a, 2b, and 2c, which are three guide portions arranged at regular intervals (120 ° intervals) in the circumferential direction along the inner circumference. The cam grooves 2a, 2b, 2c have trapezoidal cross sections having flank angles (inclination angles formed by both groove wall surfaces on a cross section perpendicular to the groove) θ1, θ2 as shown in FIG. The cam followers 1a, 1b, 1c are slidably fitted. The flank angles θ1 and θ2 are set to smaller angles that make it difficult for the cam follower to come out when an external force acts on the cam follower during the forward / backward movement. In the case of the present embodiment, the flank angles θ1 and θ2 are both 23 °.
[0041]
The inclination K of the cam groove in the axial direction is the inclination of the tangent line of the cam groove center line with respect to the axis C0 of the tangent of the cam groove, as shown in FIG. It is given by a value obtained by dividing by the length component Z0 of the tangent line segment in the axial direction C,
K = G0 / Z0 (1)
And
[0042]
The cam frame 2 is a member that is injection-molded by a mold device 11 (FIG. 4) according to a second embodiment of the present invention, which will be described later. This is an inner slide-type mold having first slide cores 4A to 4D and second slide cores 5A to 5D (FIGS. 6 and 7) divided into eight (the number of divisions 2j = 8). As described above, molding by the eight-part mold reduces the arc central angle ω1 or ω2 (FIG. 6), which is the central angle of the arc formed by one slide core, and the flank of the cam groove as described above. Even if the angle is smaller, the member can be die-cut. The value of j indicates the number of each of the first slide core and the second slide core, and in the case of the present embodiment, j = 4.
[0043]
Eight parting lines (parting lines) 2d, which are portions where the first slide core and the second slide core are joined, remain on the inner periphery of the cam frame 2 as a molded member (FIG. 3). Each cam groove is arranged so as to straddle at least one of the parting lines. The number of the parting lines is not an integral multiple of the three cam grooves. Therefore, even if three equally spaced cam grooves 2a, 2b, 2c intersect the eight parting lines 2d, the cam followers 1a that fit into the cam grooves 2a, 2b, 2c during rotation of the cam frame 2. , 1b, 1c do not simultaneously affect the parting line 2d.
[0044]
In the case where the mold is formed using a mold to which a six-part slide core is applied as in a conventional mold, six mold parting lines 2d 'remain. When the three cam grooves 2a, 2b, and 2c are arranged at equal intervals, the number of the parting lines 6 is an integral multiple of the number of the cam grooves 3. Therefore, the cam followers 1a, 1b, and 1c simultaneously relate to the parting line. there is a possibility. Furthermore, since the center angle of the arc formed by one slide core is widened, the cam groove having the smaller flank angle as described above cannot be die-cut at and near the parting line.
[0045]
In the lens frame device 10, the movable frame 1 is supported by a rotation member being restricted by a fixed member (not shown). When the cam frame 2 is driven to rotate, the cam grooves 2a, 2b, 2c cause the cam followers 1a, 1c to move. It is driven forward and backward (for example, zoom drive) along the axial direction C via 1b and 1c.
[0046]
According to the lens frame device 10 of the present embodiment, since the cam frame 2 is formed by the mold of the slide core divided into eight, the flank angles θ1 and θ2 of the cam grooves 2a, 2b and 2c can be further reduced. Therefore, when an external force acts on the cam follower, the cam frame 2 does not easily come off, and has excellent strength against the external force. Further, since eight parting lines are provided for the three cam grooves, the cam followers can be prevented from being simultaneously positioned on the parting line, so that the moving frame 1 can be smoothly advanced and retracted. .
[0047]
The same effect can be obtained by using a female helicoid screw and a male helicoid screw in place of the cam groove as the guide portion and the cam follower as the guided portion. Furthermore, a similar effect can be obtained by applying a frame that rotates with respect to the cam frame 2 instead of the moving frame 1, and in this case, the cam groove is replaced with a groove along the circumferential direction, and the cam follower is circular. Replaced by ribs along the circumferential direction. Further, the number of the cam grooves may be three or more as described later, and the same effect can be obtained even if the number of mold divisions 2j is eight or more. However, it is necessary that the number of divisions is not an integer multiple of the number of cam grooves.
[0048]
Next, a mold apparatus according to a second embodiment of the present invention will be described with reference to FIGS.
FIG. 4 is a longitudinal sectional view of the mold apparatus according to the second embodiment in a mold-clamped state (a state in which the mold is closed). FIG. 5 is a longitudinal sectional view of the mold apparatus in a mold open state (a state in which the mold is opened). FIG. 6 is a plan view of the inner slide die (slide insert) of the die device as viewed from the axial direction. FIG. 7 is a sectional view taken along line AA of FIG. FIGS. 8A and 8B are perspective views of two slide cores of the inner slide mold. FIG. 9 is a perspective view of a center core of the inner slide mold.
[0049]
As shown in FIGS. 4 and 5, the mold apparatus 11 of the present embodiment includes a fixed mold 6 and a movable mold 7, and a mold for molding the cam frame 2 of the first embodiment. Device.
[0050]
The fixed die 6 has a fixed-side insert, an outer slide core driving angular pin (not shown), and a backup plate.
[0051]
The movable die 7 includes a center core receiver 7A, a slide core receiver 7B, a movable insert 7C, an outer slide core 7D, and an inner slide mold 12.
[0052]
The inner slide die 12 has one center core 3 having an axis C0, four first slide cores 4A, 4B, 4C, 4D and four second slide cores 5A, 5B, 5C, 5D. It becomes. The first slide cores 4A, 4B, 4C, and 4D and the four second slide cores 5A, 5B, 5C, and 5D are alternately arranged around the center core 3 at an interval of 45 ° and each have an axis C0. Are arranged so as to be slidable in the radial direction and in the axial direction.
[0053]
The first slide cores 4A, 4B, 4C, 4D have the same shape, and the second slide cores 5A, 5B, 5C, 5D also have the same shape. Only the shape of the first slide core 4A and the second slide core 5A of the set will be described.
[0054]
The first slide core 4A is a dovetail portion 4a inclined by an inclination angle α with respect to the axis C0 of the center core, and a part of a cylindrical surface centered on the axis C0. A cylindrical surface 4e for forming a surface, a convex portion 4f provided on the cylindrical surface 4e for forming a cam groove of a cam frame, and an inclined surface disposed on both sides thereof along the dovetail portion 4a. It has a sliding contact surface 4b, which is a surface, and a slide guide portion 4d formed to extend in the radial direction of the axis C0 on the core receiving end side.
[0055]
The sliding contact surface 4b is a surface that slides on the center core 3 and abuts on the second slide core 5A. The first sliding contact surface 4b of the sliding contact surface 4b passes through the axis C0 and the dovetail portion 4a. The inclination angle on a cross section parallel to a plane including the slide core center line (C0-A cross section, see FIG. 11) is equal to the angle α. The angle formed by the sliding contact surface 4b with respect to a straight line perpendicular to the C0-A cross section in a cross section orthogonal to the axis C0, that is, the inclination angle is defined as an angle γ.
[0056]
Further, the angle of the cylindrical surface 4e in the circumferential direction with respect to the axis C0 of the fixed nested end surface has an arc center angle ω1, and in the example of the present embodiment, the arc center angle ω1 is 60 °. However, it may be set appropriately within the range of 55 ° ≦ ω1 ≦ 70 °. Further, the central angle of the arc becomes narrower as it goes down toward the core receiving side in the direction of the axis C0 because of the inclination angle α.
[0057]
The second slide core 5A has a dovetail portion 5a extending in a direction inclined by an inclination angle β larger than the inclination angle α with respect to the axis C0 of the center core, and a cylindrical surface around the axis C0. A cylindrical surface 5e for forming the inner peripheral surface of the cam frame 2, a convex portion 5f provided on the cylindrical surface 5e for forming a cam groove of the cam frame, and a cylindrical surface 5e. A contact surface 5g provided on both sides, a sliding surface 5b arranged at a predetermined opening angle on both sides of the dovetail portion along the dovetail portion 5a, and a shaft on the core receiving end. And a slide guide portion 5d formed to extend in the radial direction of the center C0.
[0058]
The sliding surface 5b is a surface that is in sliding contact with the center core 3 in the direction of the axis C0, and is a surface (C0) of the sliding surface 5b that includes the center line of the second slide core passing through the axis C0 and the dovetail portion 5a. −A ′ cross section, see FIG. 11) is equal to the above angle β.
[0059]
The contact surface 5g contacts the inside of the sliding contact surface 4b of the first slide core 4A, and is a surface that can be in close contact with the contact surface 5g. The contact surface 5g has a cross section orthogonal to the axis C0. Is an angle (γ + 45 °) with respect to the direction perpendicular to the cross section C0-A ′.
[0060]
An arc center angle ω2 with respect to the axis C0 of the end face portion of the fixed nest side of the cylindrical surface 5e is defined as an arc center angle ω2. The arc center angle ω2 is given by (90 ° −ω1).
[0061]
In the present embodiment, the projections 4f and 5f of the first and second slide cores straddle at least one portion between the circumferential surfaces 4e and 5e of the first and second slide cores.
[0062]
The center core 3 is inclined by the inclination angles α and β with respect to the axis C0, and is provided with four dovetail grooves 3a and 3b alternately arranged at eight divided positions on the outer periphery and the dovetail grooves 3a and 3b. The sliding core has sliding surfaces 3c and 3d which abut on and slide on the sliding contact surface 4b or the sliding surface 5b of the slide core, respectively. The end of the center core 3 is fixed to and supported by the center core receiver 7A. The sliding surface 3c is arranged along the dovetail groove 3a and has an opening angle (180 ° -2γ) on a cross section perpendicular to the axis C0. The sliding surface 3d is disposed along the dovetail groove 3b, and has a predetermined opening angle that allows sliding contact with the sliding surface 5b on a cross section perpendicular to the axis C0.
[0063]
In the inner slide mold 12, the dovetail grooves 3a and 3b of the center core 3 having different inclination angles α and β with respect to the axis C0, and the first and second slide cores having the same inclination angles α and β. The dovetail portions 4a and 5a of 4A and 5A engage with each other in a dovetail manner.
[0064]
In the mold clamping state of the mold apparatus 11, that is, in a state in which the mold is closed, the contact surface 5g of the second slide core 5A is provided inside the slide contact surface 4b of the first slide core 4A. They are in close contact. When the center core 3 moves toward the center core receiver 7A relative to the first and second slide cores 4A and 5A when the mold is opened, the first and second slide cores 4A and 5A are moved out of the axis C0. Move so that it contracts toward one side. The moving amount is set to be larger in the second slide core 5A than in the first slide core 4A. Therefore, interference between the sliding contact surface 4b of the first slide core 4A and the contact surface 5g of the second slide core 5A is prevented. The cut surface 5c of the second slide core 5A is a portion provided so that when it is narrowed, the slide surface 5b does not interfere with the dovetail portion 4a of the first slide core 4A.
[0065]
Next, the operation of molding the cam frame 2 by the mold apparatus 11 having the above-described configuration will be described.
[0066]
When the cam frame 2 is formed, the fixed mold 6 and the movable mold 7 of the mold apparatus 11 are clamped as shown in FIG. In the clamped state, the center core 3 is completely inserted into the first and second slide cores 4 and 5, and the first and second slide cores 4 and 5 are movable movable inserts 7C. Is pressed down. In this state, one cylindrical column is formed by the cylindrical surfaces 4e and 5e of the first and second slide cores 4 and 5, and a cylindrical portion of the cam frame 2 is formed between the cylindrical surface and the inner peripheral surface of the outer slide core 7D. Further, the sliding contact surface 4b of the first slide core 4 and the contact surface 5g of the second slide core 5 come into close contact with each other.
[0067]
The resin is injected and injected from the gate portion 8 of the fixed-side insert under the mold-clamped state to form the cam frame 2.
[0068]
Then, after the outer slide core 7D is slid in the direction orthogonal to the axis C0, the movable die 7 is moved in the direction of the axis C0 to open the mold opening Pa, and the outer slide core 7D slides by the action of the angular pin. I do. Further, the center core receiver 7A is moved in the direction of the axis C0 to open the mold opening portion Pb to bring the mold open state (FIG. 5). By the movement of the center core receiver 7A, the first and second slide cores 4, 5 are moved inwardly via the dovetail grooves 3a, 3b of the center core 3.
[0069]
The cam grooves 2a, 2b, 2c of the cam frame 2 molded in the above-mentioned mold open state are disengaged from the projections 4f, 5f of the first and second slide cores, and the cam frame 2 is released and can be taken out.
[0070]
On the inner peripheral surface of the formed cam frame 2, eight parting lines (parting line traces, parting lines) 2 d are slightly inclined with respect to the substantially axial direction C as shown in a developed view of FIG. 3. Attached in state. The parting line 2d is a trace of a mold-matching line portion between each of the sliding contact surfaces 4b of the first slide cores 4A to 4D and each of the contact surfaces 5g of the second slide cores 5A to 5D in close contact with each other. is there. However, the part where the parting line 2d cuts the cam grooves 2a, 2b, 2c is an uneven line obtained by diagonally cutting the cam groove.
[0071]
Further, in the present embodiment, a region between right and left in the drawing in a region sandwiched by the parting line 2d in FIG. 3 is formed by the first slide core 4, and is sandwiched by the parting line 2d in FIG. In the drawing, a region that extends leftward in the drawing is formed by the second slide core 5.
[0072]
As described above, by opening the mold apparatus 11, the first slide cores 4A to 4D and the second slide cores 5A to 5D are at least set so that the cam frame 2 can be taken out with the cam frame 2 being able to be taken out toward the axis C0. It is necessary to reduce the depth of the groove. At this time, the sliding amount of the first slide cores 4A to 4D is adjusted so that the sliding contact surface 4b of the first slide cores 4A to 4D does not interfere with the contact surface 5g of the second slide cores 5A to 5D inside. The slide amount of the second slide cores 5A to 5D is increased by a predetermined amount. The sliding amount is determined by the inclination angles α and β of the center core or the dovetail groove of the slide core, the inclination angle γ of the sliding contact surface of the slide core, and the like.
[0073]
A method of determining the inclination angles α and β of the dovetail groove and the inclination angle γ of the sliding contact surface will be described with reference to FIGS.
FIG. 10 is a view of the moving state of the adjacent first and second slide cores when the mold is opened, as viewed from the axial direction, and shows a position in a mold clamped state and a slide position in the mold open state. FIG. 11 is a partially enlarged view of the slide core of FIG.
[0074]
The movement state of the other first and second slide cores 4B to 4D and 5B to 5D is the same as the movement state of the first and second slide cores 4A and 5A shown in FIG. Therefore, only the movement state of the first and second slide cores 4A and 5A will be described below.
[0075]
As shown in FIG. 10, when in the mold clamping state, the outer peripheral surfaces 4e, 5e of the first slide core 4A and the second slide core 5A are located along a predetermined cylindrical surface. When the center core 3 retreats to the mold open state, the first slide core 4A and the second slide core 5A slide by a predetermined amount in the direction D1 or the direction D2, respectively (shown by a two-dot line in FIG. 10). ).
[0076]
Now, in the mold clamping state, one point on the contact portion of the sliding contact surface 4b of the first slide core 4A is P1, and one point on the contact portion of the contact surface 5g of the second slide core 5A is P1. Let it be point P2. In the mold open state, the point P1 of the sliding contact surface 4b moves in a direction parallel to D1 (a line connecting the axis C0 and the center A of the first slide core) to reach the moving point P3. On the other hand, a point P2 of the contact surface 5g is moved in a direction parallel to D2 (a line connecting the axis C0 and the center A 'of the second slide core) to a point P3 which is the same point as the above-mentioned moving point. Prevent interference by reaching. However, in setting the actual movement amount, it is necessary to consider a dimensional error of the mold as described later. Therefore, on the point P3, a predetermined gap is left between the sliding contact surface 4b of the first slide core 4A and the contact surface 5g of the second slide core 5A by design, so that the above-described inclination angles are set. I do.
[0077]
The conditions of the dovetail groove inclination angles α and β for moving the points P1 and P2 on the first and second slide cores to the position of the movement point P3 and the inclination angle γ of the sliding contact surface are calculated as follows. Obtained from the formula.
[0078]
That is, as shown in FIG. 11, the amount of movement of the first slide core 4 in the direction D1 is defined as the movement distance L1 between the points P1 and P3, and the amount of movement of the second slide core 4 in the direction D2 is defined as the movement of the points P2 and P3. It is assumed that the distance is L2. When the number of divisions is N, the number of divisions N is 2j, where j is the number of the first and second slide cores, and the mold division angle ε (angle P1−P3−P2) is N in this embodiment. = 8, ie, j = 4,

It is.
[0079]
Assuming that the sliding amount S of the center core 3 in the direction of the axis C0 (FIG. 5), the moving distances L1 and L2 are:
L1 = S × tanα (3)
L2 = S × tanβ (4)
It is. On the other hand, from the triangle formed by the points P1, P2 and P3,
L2 × cosε = L1 + L2 × sinε × tanγ (5)
Is obtained.
[0080]
From the above equations (2) to (5), the relationship between the inclination angles α, β, and γ is:

It becomes.
[0081]
However, even if the inner slide mold 12 is manufactured as in the above equation (6), the first slide cores 4A to 4D and the second slide cores 5A to 5D interfere with each other due to a processing error or the like, and the mold operates. May cause problems. Therefore, in order to surely avoid the above-mentioned interference, the following expression is satisfied from experience. That is,
β ≧ tan ^-1 $ 2 ^1/2 × tanα / (1-tanγ)｝ + 0.1 ° (7)
Thus, it is desirable to set the inclination angle β to be slightly large.
[0082]
It is desired to set the inclination angle β to be larger from the operation. However, if it is set too large, the shape of the inner slide mold 12 itself will not be established. Therefore, the inclination angle β is set with respect to the inclination angles α and γ with a predetermined restriction as in the following equation. That is,

More desirably.
[0083]
Here, specific numerical settings of the inclination angles α, β, γ of the inner slide mold 12 will be described.
If the inclination angle α is too large, the tip of the center core 3, that is, the upper end in FIG. 7 becomes thin, and the strength of the center core 3 becomes insufficient. On the other hand, if the inclination angle α is too small, the center core movement distance S (FIG. 5), that is, the movement in the axial direction is not increased beyond the limit of the stroke of the movable die. The amount of indentation inside the slide core 4 is insufficient, and the cam groove cannot be removed from the mold.
[0084]
On the other hand, the inclination angle β is the same as the inclination angle α. If the inclination angle β is too large, the tip end (upper end in FIG. 7) of the center core 3 becomes thinner, and the strength of the center core 3 becomes weaker. If β is too small, the amount of inward squeezing of the second slide core 5 becomes insufficient unless the center core moving distance S is increased, and similarly, the cam groove cannot be removed from the mold.
If the inclination angle γ is set too small, the width end portions of the first slide cores 4A to 4D become knife-edge-shaped and are easily broken. Conversely, if the inclination angle γ is too large, the inclination angle β also needs to be increased, which causes a problem when the inclination angle β is increased.
[0085]
In view of the circumstances described above, it was found from the results of an actual production of a mold and an experiment that it is desirable that the inclination angles α and γ adopt values in the following ranges. That is,
The inclination angle α is
1.0 ° ≦ α ≦ 4.0 ° (9)
Preferably,
1.5 ° ≦ α ≦ 2.5 ° (10)
And
[0086]
The inclination angle γ is
0 ° ≦ γ ≦ 30 ° (11)
Preferably,
5 ° ≦ γ ≦ 20 ° (12)
And
[0087]
On the other hand, as for the above-mentioned inclination angle β, when the above-mentioned inclination angles α and γ are applied, it is desirable to apply a value in a range obtained by the following equation. That is,
β ≧ 2 ^1/2 × α / (1-tanγ) + 0.1 ° (13)
More preferably,
2 ^1/2 × α / (1-tanγ) + 0.175 ° ≦ β
≦ 2 ^1/2 × α / (1-tanγ) + 1.5 ° (14)
And In this case, both α and β are small values of several degrees.
[0088]
The above-described setting ranges are obtained by actually studying the manufacture of the mold. In particular, in the inner slide mold 12 of the present embodiment, the inclination angle α = 2.0 °, the inclination angle β = 4.5 ° and the inclination angle γ = 15.0 ° are employed.
[0089]
Next, the removal of the cam groove of the cam frame 2 by the inner slide die 12 of the present embodiment will be described.
FIG. 1 is a cross-sectional view of the cam frame 2 as viewed from the direction in which the first slide core 4A is removed. In the range between the two parting lines 2d, the portions where the cam grooves 2b are undercut are not shown. Absent. That is, the cam frame 2 can be molded and released from the inner slide die 12 of the present embodiment having the eight divided first and second slide cores.
[0090]
However, in the mold having the six-part slide core according to the conventional technique, the space between the parting lines 2d 'is wider as shown in FIG. Therefore, in a range sandwiched by the parting line 2d ', an undercut is formed in an end region of the cam groove 2b. That is, with the above-mentioned conventional mold, the cam frame 2 of the present embodiment cannot be formed and released.
[0091]
FIG. 12 shows the inclination of the cam groove with respect to the axis (inclination with respect to the axis of the cam groove) K when the flank angle θ is used as a parameter, and the cam of the flank angle θ (θ 1 or θ 2). FIG. 7 is a diagram showing a relationship with a circular arc center angle ω (ω1 or ω2) of a slide core in which a groove can be removed, that is, an undercut portion does not occur.
[0092]
According to FIG. 12, for example, when the arc center angles ω1, ω2 are 60 ° and the inclination of the anti-axial center K = 1.05, if the flank angles θ1, θ2 are 20.0 ° or more, the die This shows that the molded article can be released from the mold. As shown in FIG. 12, the smaller the inclination K of the cam groove with respect to the axial center (ie, the steeper the cam groove is with respect to the rotation angle), and the smaller the flank angle θ, the more the slide core that can be die-cut. Becomes smaller. That is, the arc width of the slide core that can be removed is narrow and limited.
[0093]
The inclination K of the cam groove with respect to the axial center is given by (circumferential distance G0 / axial distance Z0) of the cam groove, and the circumferential distance G0 is a circumferential distance at the maximum diameter of the cam groove. . Usually, the range of 0.65 to 1.25 shown in FIG. As described above, the value of K has a great influence on the die cutting, and is particularly important in the parting line (parting line) and its vicinity.
[0094]
In the case of the above-described mold to which the conventional six-piece slide core is applied, the arc center angle ωb of the slide core shown in FIG. 12 is in a range of about 70 ° to 80 °. Therefore, although it depends on the inclination K of the center axis of the cam groove, if the flank angle θ is not more than about 22.5 °, it becomes difficult to remove the mold.
[0095]
On the other hand, in the case of the inner slide mold 12 to which the eight-part slide core is applied in the present embodiment, the arc center angle ωa of the slide core shown in FIG. 12 is in a range of approximately 55 ° to 70 °. Therefore, although it depends on the inclination K of the center axis of the cam groove, the flank angle θ is about 16.5 ° or more, the die can be removed, and the shape of the cam groove is less restricted.
[0096]
The cam frame was experimentally molded by a mold based on the above-described cam groove removal state. As a result, the inner slide mold 12 of the present embodiment has three cam grooves and eight divisions. In this case, the flank angles θ1 and θ2 of the cam groove and the inclination K of the cam groove are as follows.
16.5 ° ≦ θ1 ≦ 28.0 °
16.5 ° ≦ θ2 ≦ 28.0 °
0.65 ≦ K ≦ 1.25 (15)
Was found to be applicable.
[0097]
When the upper limits of the flank angles θ1 and θ2 are suppressed,
16.5 ° ≦ θ1 ≦ 27.5 °
16.5 ° ≦ θ2 ≦ 27.5 °
0.70 ≦ K ≦ 1.25 (16)
Was found to be applicable.
[0098]
Further, when the upper limits of the flank angles θ1 and θ2 are suppressed,
16.5 ° ≦ θ1 ≦ 26.5 °
16.5 ° ≦ θ2 ≦ 26.5 °
0.80 ≦ K ≦ 1.25 (17)
Was found to be applicable.
[0099]
Note that the above formulas (15), (16), and (17) also apply to the case where the number of cam grooves is one or more and the number of divisions is eight or more in terms of the number of the cam grooves and the number of mold dies. Further, the above formulas (15), (16), and (17) are also applicable to a female helicoid screw provided on the inner periphery of the tubular member instead of the cam groove of the cam frame. .
[0100]
As described above, since the inner slide mold 12 of the present embodiment is formed by an eight-part slide core, the arc center angles ω1 and ω2 of each slide core can be set small, and the flank angle θ1 , Θ2 can be formed, and a lens frame device which is excellent in strength and can prevent problems such as the cam follower from coming off the cam groove can be formed.
[0101]
Also, for three of the cam followers 1a, 1b, and 1c, there are eight parting lines 2d of the cam frame 2 formed by the inner slide die 12 of the present embodiment. Therefore, in the lens barrel device 10 of the first embodiment, the three cam followers 1a, 1b, 1c do not pass through the parting line 18 at the same time. Therefore, a large driving force is not required during the zoom operation of the lens frame device 10, and furthermore, the problem that the photographed image fluctuates and the descriptive power decreases is less likely to occur.
[0102]
Further, as a secondary effect, as a cylindrical member applied to the zoom lens barrel of the camera, a special shape having a cylindrical shape on the front side and a square cylindrical shape on the camera body side end as shown in the perspective view of FIG. There is a lens frame member 21 that has been formed. However, if the eight-segment inner slide die 12 of the present embodiment is applied to molding of the lens frame member, a square cylinder of the lens frame member 21 is used because eight slide cores are used. It is possible to form a well-balanced part.
[0103]
In the inner slide mold 12 of the second embodiment, the first and second slide cores 4 and 5 are dovetailedly engaged with the center core 3, but this coupling structure is limited to dovetailed engagement. For example, various engaging means such as T-groove engagement can be used as long as the two members can be slidably engaged with each other.
[0104]
Further, the sliding surface 5b of the second slide core and the sliding surface 3d of the center core slidingly contacting the surface in the inner slide die 12 of the second embodiment are formed as single surfaces, respectively. The surface may be divided into a plurality of surfaces. Further, the contact slide surface 4b of the first slide core, the slide surface 3c of the center core and the contact surface 5g of the second slide core that are in contact with the contact slide surface 4b may be formed as a plurality of separate surfaces. . However, in this case, the inclination angle γ indicates a portion indicating the largest angle.
[0105]
Although the inner slide mold 12 employs an eight-segment slide core, the same structure can be applied to an inner slide mold having an even number N of slide cores not limited to the above-described eight-segment division. A similar effect can be obtained by applying. In this case, the division number N is (the number j of the first slide cores) × 2, and the division angle ε is given by 360 ° / 2j.
[0106]
The inclination angles α, β, and γ of the center core, the first slide core, and the second slide core in the N-divided inner slide die need to satisfy the following relationship. That is, assuming that j = N / 2,
β ≧ tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.1 ° (18)
It is more desirable that the following relationship be satisfied. That is,
tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.175 ° ≦ β
≤tan ^-1 {Tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 1.5 ° (19)
It is desirable that
[0107]
Here, a case where the number of divisions N is 10, that is, an example of an inner slide mold of 10 divisions will be described. This inner slide mold of 10 divisions has one center core, five first slide cores, This is a mold for forming a cam frame composed of five second slide cores. The first slide cores and the second slide cores are alternately arranged around the center core at an interval of 36 °. Other configurations are the same as those of the inner slide mold 12 of the second embodiment.
[0108]
The cam frame formed by this 10-piece inner slide mold has ten parting lines on its inner periphery. In the inner periphery of the cam frame, similarly to the cam frame 19 of the first embodiment, a cam groove of the same shape is formed on the inner periphery of the cam frame at approximately 120 ° in the circumferential direction. A cam follower provided on the moving frame is slidably fitted in the cam groove.
[0109]
When the cam frame is taken out of the mold after the molding of the cam frame, the first slide core and the second slide core are narrowed inward similarly to the inner slide mold 12 of the second embodiment.
[0110]
The inclination angles α, β, and γ of the center core and the first and second slide cores of the above-described ten-segment inner slide die need to satisfy the following relationship. That is,
β ≧ tan ^-1 {Tan α / (cos 36 ° −sin 36 ° × tan γ)} + 0.1 ° (20)
It is necessary to be.
[0111]
Further, it is desirable to satisfy the following relationship. That is,
tan ^-1 {Tan α / (cos 36 ° −sin 36 ° × tan γ)} + 0.175 ° ≦ β
≤tan ^-1 {Tan α / (cos 36 ° −sin 36 ° × tan γ)} + 1.5 ° (21)
It is desirable that
[0112]
When the above-described ten-part inner slide mold is applied, the arc center angle ω of each slide core is further smaller than that of the inner slide mold 12 of the second embodiment, and from the center of the substantially trapezoidal cam groove cross section, The angle θ1 or θ2 between the straight line extending perpendicularly to the center axis of the cam frame and each wall of the cam groove can be further reduced, and a cam frame having more excellent strength can be formed.
[0113]
Further, since there are ten parting lines for three cam follower pins, three cam pins do not pass through the parting line at the same time. Therefore, a large driving force is not required during the zoom operation, and the problems that the captured image is shaken and the descriptive power is reduced are less likely to occur.
[0114]
Next, as a modified example of the cam groove of the cam frame that can be formed by the inner slide mold 12, a cam groove having a shape shown in the sectional views of FIGS. 14A and 14B can be proposed.
[0115]
The cam groove 22a of the cam frame 22 of the modified example shown in FIG. 14A is a cam groove whose inner surface is formed by a curved surface. The cam follower 23a of the moving frame 23 which is slidably fitted in the cam groove 22a is a cam follower having a spherical tip portion that matches the cross-sectional shape of the cam groove 22a.
[0116]
Further, the cam groove 24a of the cam frame 24 of the modified example shown in FIG. 14B has a shape in which a further inclined surface is provided at the bottom of the groove. The cam follower 25a of the moving frame 25 which is slidably fitted into the cam groove 24a is a cam follower having a chamfered tip portion that matches the cross-sectional shape of the cam groove 24a.
[0117]
In this modification, these cam grooves 22a, 24a are also treated as substantially trapezoidal cam grooves, and the flank angles θ1, θ2 in the cam grooves 22a, 24a shown in FIGS. Indicates a portion where the angle between the straight line extending perpendicularly from the center of the substantially trapezoidal cam groove cross section to the center axis of the cam frame and the side wall of the cam groove becomes the smallest. Then, the inclination angles α, β, and γ of the center core and the slide core in the inner slide die described above can be obtained by using the above-described arithmetic expressions.
[0118]
Next, a lens barrel device which is a cylindrical member device according to a third embodiment of the present invention will be described with reference to FIG.
FIG. 15 is a developed view of the lens frame of the lens frame device as viewed from the inner peripheral side.
[0119]
The lens barrel device according to the present embodiment is applied to a zoom lens barrel of a camera, and mainly includes a helicoid frame 31 and a moving frame 32. The helicoid frame 31 is a cylindrical member that can be formed by a mold having substantially the same configuration as the mold device 11 of the second embodiment.
[0120]
The helicoid frame 31 is provided with female helicoid screws 31a, 31b, 31c, which are guide portions, at three locations on the inner peripheral surface at intervals of 120 ° at two intervals.
[0121]
The movable frame 32 is provided with male helicoid screws 32a, 32b, and 32c, which are guided portions, at three locations on the outer peripheral surface at intervals of 120 ° at two intervals (indicated by broken lines in FIG. 15). The moving frame 32 is fitted into the inner periphery of the helicoid frame 31 in a state where the male helicoid screws 32a, 32b, and 32c are screwed into the female helicoid screws 31a, 31b, and 31c. Supported in state.
[0122]
In the lens frame device, when the helicoid frame 31 is driven to rotate, the moving frame 32 moves forward and backward along the axial direction C via the helicoid screw.
[0123]
The helicoid frame 31 has a helicoid inner slide metal in which the convex portions 4f and 5f for forming the cam grooves of the inner slide die 12 shown in the second embodiment are replaced with helicoid convex portions for forming female helicoid screws. It can be molded by a mold.
[0124]
Also in this inner slide mold for helicoid, the inclination angles α, β, and γ of the center core and the slide core can be obtained using the above-described arithmetic expressions, similarly to the inner slide mold 12.
[0125]
As shown in FIG. 15, eight parting lines 31d are formed on the inner peripheral surface of the helicoid frame 31 formed by the inner slide die for helicoid. When the helicoid frame 31 is rotationally driven, even if one of the two male helicoid screws 32a, 32b, 32c having the moving frame 32 is on the parting line 31d of the helicoid frame 31, the other male helicoid screws are not used. At least one of them is not located on the parting line 31d.
[0126]
According to the lens frame device of the present embodiment, the helicoid frame 31 has female helicoid screws 32a, 32b, and 32c corresponding to the flank angles θ1 and θ2 of the cam groove 15, similarly to the cam frame 2 in the first embodiment. Even if the flank angle is small, molding and release can be performed, and a zoom frame having excellent strength can be obtained. Further, even if the two male helicoid screws are on the parting line 31d of the helicoid frame 32 as described above, at least one of the other male helicoid screws is not located on the parting line 31d. A large driving force is not required in the inside, and furthermore, the problems that the photographed image fluctuates and the drawing power is reduced are less likely to occur.
Next, a lens barrel device as a cylindrical member device according to a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 16 is a development view of the lens frame of the lens frame device as viewed from the inner peripheral side.
[0127]
The lens barrel device of the present embodiment is applied to a part of a lens barrel of a camera, and mainly has a fixed frame 41 and a rotating frame 42. The fixed frame 41 is a cylindrical member that can be formed by a mold having substantially the same configuration as the mold device 11 of the second embodiment.
[0128]
The fixed frame 41 is provided with a guide groove 41b, which is a single guide portion along the circumferential direction, on the inner peripheral surface, and is further provided with three protrusion insertion ports 41a communicating with the guide groove 41b.
[0129]
The rotating frame 42 is provided with three projections 42a, which are guided portions, on the outer peripheral surface (indicated by broken lines in FIG. 16). The rotating frame 42 is inserted into the inner periphery of the fixed frame 41 by inserting the projection 42a through the projection insertion opening 41a, and is slidably fitted into the guide groove 41b. The rotating frame 42 is moved in the axial direction C with respect to the fixed frame 41. Is rotatably supported in a regulated state.
[0130]
The fixed frame 41 is formed by an inner slide die in which the convex portions 4f and 5f for forming the cam groove of the inner slide die 12 shown in the second embodiment are replaced with convex portions along the circumferential direction. can do.
[0131]
In the above inner slide die, similarly to the inner slide die 12, the inclination angles α, β, γ of the center core and the slide core can be obtained by using the above-mentioned respective arithmetic expressions. The fixed frame 41 formed by the inner slide die is provided with eight parting lines 41d as shown in FIG. Therefore, even if one of the three projections 42a of the rotating frame 42 arranged at equal intervals in the circumferential direction is located on the parting line 41d, at least one of the other projections 42a is not located on the parting line 41d.
[0132]
Therefore, according to the lens barrel device of the present embodiment, a smooth rotating state can be obtained without the need for a driving force that fluctuates greatly during the lens barrel rotating operation.
[0133]
The same effect can be obtained in a lens frame device in which the guide groove 41b of the fixed frame 41 is a guide portion along the convex circumferential direction and the projection 2a of the rotating frame 42 is a concave portion.
[0134]
Next, a lens barrel device which is a cylindrical member device according to a fifth embodiment of the present invention will be described with reference to FIG.
FIG. 17 is a development view of the lens frame of the lens frame device as viewed from the inner peripheral side.
[0135]
The lens barrel device according to the present embodiment is applied to a part of a lens barrel of a camera, and mainly includes a cam frame 45 and a moving frame 46.
[0136]
The cam frame 45 can be molded by a mold device in which the number of divisions of the mold device 11 of the second embodiment is six, and the number of cam grooves of a guide portion provided on the inner periphery is four. This is a frame that is a book. That is, in the cam frame 45, four cam grooves 45a, 45b, 45c, 45d are arranged on the inner peripheral surface at regular intervals of 90 ° in the circumferential direction.
[0137]
In the moving frame 46, four guided portions of cam followers 46a, 46b, 46c and 46d are arranged on the outer peripheral surface at regular intervals of 90 ° in the circumferential direction. The moving frame 46 is incorporated into the cam frame 45 by slidably fitting the cam followers into the cam grooves of the cam frame 45.
[0138]
In the present mirror frame device, when the cam frame 45 is rotationally driven, the moving frame 46 is driven forward and backward in the axial direction C via the cam groove.
[0139]
In order to form the cam frame 45, the number of projections for forming the cam grooves of the inner slide mold 12 shown in the second embodiment was set to four, and the number of divisions of the slide core was set to six. Apply inner slide mold.
[0140]
In this inner slide die, similarly to the inner slide die 12, the inclination angles α, β, γ of the center core and the slide core can be obtained by using the above-mentioned arithmetic expressions. However, the number 2j of the slide cores is set to 6.
[0141]
The cam frame 45 formed by the inner slide die is provided with six parting lines 45d as in the conventional six-part inner slide die as shown in FIG. However, since there are four cam grooves and four cam followers 46a, 46b, 46c, and 46d, which are not an integer multiple of the number of divisions of the die 6, the four cam followers 46a, 46b, and 46c of the moving frame 46 are provided. , 46d are located on the parting line 45d, but at least one of the other cam followers 46a, 46b, 46c, 46d is not located on the parting line 45d.
[0142]
Therefore, according to the lens frame device of the present embodiment, a driving force that greatly fluctuates during rotation of the cam frame is not required, and a smooth moving state of the moving frame can be obtained.
[0143]
Next, an inner slide die of a die apparatus according to a sixth embodiment of the present invention will be described with reference to the perspective view of the inner slide die shown in FIG.
As shown in FIG. 18, the inner slide mold 51 of this embodiment is an eight-part slide mold having no slide core guide dovetail, and includes a center core 52 and a 45 ° angle around the center core 52. Four first slide cores 53A, 53B, 53C, 53D and four first slide cores 54A, 54B, 54C, 54D alternately arranged at intervals, and four first slide cores each slightly inclined with respect to the axis C0. 1 and 2 angular pins 55 and 56. The inner slide mold 51 is incorporated into a movable mold (not shown), is driven to a mold clamping position and a mold opening position, and is a mold for injection molding a cam frame of a cylindrical member having an inner peripheral cam groove. .
[0144]
The first slide cores 53A, 53B, 53C, 53D have the same shape, and the second slide cores 54A, 54B, 54C, 54D also have the same shape. Only the shapes of the first slide core 53A and the second slide core 54A will be described.
[0145]
The first slide core 53A is a part of a cylindrical surface centered on the axis C0, the cylindrical surface 53a for forming the inner peripheral surface of the cam frame, and the first slide core 53A is provided on the cylindrical surface 53a. A convex surface 53b for forming the cam groove, an inner peripheral side projection 53f, and an abutting surface of an inclined surface provided on both inner sides of the cylindrical surface 53a and having a predetermined opening angle along the axis C0 direction. 53g, a slide guide 53d extending in the radial direction of the axis C0 on the core receiving end side, and provided on the slide guide 53d, and inclined toward the axis C0 by a predetermined angle α. It has an angular pin hole 53e. The first slide core 53A is slidably supported in a radial direction by a movable inner slide receiver (not shown).
[0146]
The second slide core 54A is a part of a cylindrical surface centered on the axis C0, the cylindrical surface 54a for forming the inner peripheral surface of the cam frame, and the second slide core 54A is provided on the cylindrical surface 54a. A convex portion 54b for forming the cam groove, an inner peripheral side projection 54f, a contact surface 54g having a predetermined opening angle along the axis C0 on both outer sides of the cylindrical surface 54a, and a core receiving portion. A slide guide portion 54d formed on the end side to extend in the radial direction of the axis C0, and provided on the slide guide 54d, and inclined toward the axis C0 by a predetermined angle β with respect to the axis C0. It has an angular pin hole 54e. The second slide core 54A is slidably supported in a radial direction by a movable inner slide receiver (not shown).
[0147]
The contact surface 53g is an inclined surface having an inclination angle γ on a plane perpendicular to the axis C0 and a direction perpendicular to a plane including the axis C0 and the center of the first slide core. The contact surface 54g is a surface that is in close contact with the contact surface 53g of the first slide core 53 at the time of mold clamping, and is located on a plane orthogonal to the axis C0 and the center of the second slide core 53. Is an inclined surface that forms an angle of inclination (γ + 45 °) with the direction orthogonal to the plane including
[0148]
Further, the convex portion 53b or 54b is separated from the cylindrical surface 53a of the first slide core and the cylindrical surface 54a of the second slide core by straddling at least one place, and is formed continuously. Shall be
[0149]
The center core 52 has a tapered shape along the axis C0, and its end is fixed to a movable center core receiving portion (not shown). The projections 53f and 54f of the first and second slide cores 53A and 54A are in contact with the center core 52 in the mold clamping state. When the mold is opened, the projections 53f, 54f of the first and second slide cores 53A, 54A and the like move inward, but the center core 52 moves with the projections 53f, 54f in the direction of the axis C0. Slide in C0 direction.
[0150]
The first angular pin 55 is fixed to a movable center core receiving portion (not shown) with its upper end inclined toward the axis C0 by an inclination angle α. And it is slidably fitted in the angular pin hole 53e of the first slide core 53A and the like.
[0151]
The second angular pin 56 is fixed to a movable center core receiving portion (not shown) with the upper end inclined toward the axis C0 by an inclination angle β. It is slidably fitted in an angular pin hole 54e of the second slide core 54A or the like.
[0152]
Since the first and second angular pins 55 and 56 are retracted toward the center core receiving portion together with the center core 52 when the mold is opened, the first and second slide cores 53A and 54A are connected via the angular pin holes 53e and 54e. It slides so as to contract toward the axis side.
[0153]
In the mold apparatus to which the inner slide mold 51 having the above-described configuration is applied, in the mold clamping state, the contact surface such as the second slide core 54A is provided inside the contact surface 53g such as the first slide core 53A. 54 g are in close contact with each other.
[0154]
When the center core 52 moves by a predetermined amount in the center core receiving direction at the time of opening the mold after resin injection and injection, the first and second slide cores 53A and 54A are guided by the inclined first and second angular pins 55 and 56. It slides inward by a predetermined amount and becomes narrowed. By the movement of the first and second slide cores 53A, 54A, etc., the projections 53b, 54b of the first and second slide cores are separated from the cam grooves of the formed cam frame, and the cam frame can be die-cut.
[0155]
The cam frame formed by the inner slide die 51 also has eight parting lines, but these lines are parallel to each other in this embodiment.
[0156]
As described above, by opening the mold device 51, at least the cam groove is formed so that the first slide core 53A and the like and the second slide core 54A and the like can be taken out with the cam frame 2 being able to be taken out toward the axis C0. It is necessary to reduce the depth. At this time, the second slide is smaller than the slide amount of the first slide core 53A or the like so that the contact surface 53g of the first slide core 53A or the like does not interfere with the contact surface 54g of the second slide core 54A or the like inside. The slide amount of the core 54A and the like is increased by a predetermined amount. The sliding amount is determined by the inclination angles α and β of the angular pins and the inclination angle γ of the contact surface of the slide core.
[0157]
The inclination angles α and β and the inclination angle γ of the inner slide die 51 of the present embodiment are calculated in the same manner as in the case of the eight-part inner slide die 12 of the second embodiment. It can be obtained by applying (8) and the like.
[0158]
According to the inner slide die 51 of the present embodiment, the same effect as that of the inner slide die 12 of the second embodiment can be obtained. That is, the cam frame formed by the inner slide mold 51 has small flank angles θ1 and θ2 of the cam grooves, and has excellent strength in which the cam follower is hard to be detached. In addition, since the cam frame has eight parting lines for three cam followers, three cam followers do not pass through the parting lines at the same time. Therefore, a large driving force is not required during the operation of the cam frame. When the cam frame is applied to a mirror frame of a camera, problems such as shaking of a photographed image and a reduction in descriptive power are less likely to occur.
[0159]
In addition, in the case of the inner slide mold 51 of the present embodiment, it is not necessary to adopt the dovetail groove structure, so that the mold can be easily manufactured, and the manufacturing cost of the mold can be reduced, the manufacturing period can be shortened, and the like.
[0160]
As described above, the molding means for molding the cylindrical member such as the cam frame and the helicoid frame shown in each of the embodiments described above is not limited to the above embodiment, and may be a metal powder injection molding in addition to the plastic injection molding. It can be applied to molding means using various molding materials, such as metal die casting, ceramic molding and the like.
[0161]
Further, in the cylindrical members such as the cam frame and the helicoid frame shown in each of the above-described embodiments, one flank angle θ1 and the other flank angle θ2 of the groove are assumed to be equal, but the present invention is not limited to this. It is also applicable to the molding of a cylindrical member having a groove or a projection having an angle different from θ2. Further, even when two or three cam grooves, helicoid screws, lateral grooves, and the like are provided in a single cylindrical member in combination, molding by the mold according to the present invention is possible.
[0162]
In addition, although the parting line of the cylindrical member molded by the mold of each of the above embodiments is provided from one end to the other end of the cam frame or the helicoid frame, the present invention is limited to such a cylindrical member. Instead, for example, the mold according to the present invention can be applied to a case where the parting line does not reach the end surface of the tubular member.
[0163]
Further, the cam groove and the lateral groove (circumferential groove) of the cylindrical member formed by the mold of each of the above embodiments are recessed with respect to the inner peripheral surface of the cylindrical member. The tubular member is not limited to this, and can be applied to a tubular cam having a convex cam or a circumferential convex portion.
[0164]
Furthermore, although the cylindrical member in each of the above-described embodiments and the modifications thereof has been described by taking the lens barrel of the camera as an example, the gist of the present invention is that, other than the lens barrel of the camera, for example, a lipstick container, a bottle, and the like It is also applicable to the molding of various caps and other mechanical parts having a molding undercut.
[0165]
The members constituting the mold in each of the above embodiments are not limited to materials such as metals such as steel and aluminum alloys. For example, ceramics, resins, composites of resin and metal powder, and other materials may be used. Can be used.
[0166]
【The invention's effect】
According to one aspect of the present invention, at least one portion of the fitting portion is not located on the parting line. Therefore, there is provided a tubular member or a tubular member device which has a small rattling and which can suppress occurrence of shaking of an image being taken and a decrease in depiction power when applied to a camera. be able to.
[0167]
According to another aspect of the present invention, a flank angle of a formed cam groove or a helicoid screw is small, a detachment of a fitting portion due to an external force hardly occurs, and a strong cylindrical member or a cylindrical member. An apparatus can be provided.
[0168]
According to yet another aspect of the present invention, at least one portion of the fitting portion is not located on the parting line. Therefore, it is possible to provide a mold capable of forming a cylindrical member having small rattling.
[0169]
According to still another aspect of the present invention, there is provided a metal member capable of forming a cylindrical member having a small flank angle such as a formed cam groove or a helicoid screw and in which a fitting portion is not easily detached by an external force. Types can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a lens barrel device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the cam frame of the lens frame device of FIG.
FIG. 3 is a developed view of the lens barrel device of FIG. 1 as viewed from an inner peripheral side.
FIG. 4 is a longitudinal sectional view of the mold apparatus according to the second embodiment in a mold-clamped state.
FIG. 5 is a longitudinal sectional view of the mold apparatus of FIG. 4 in a mold open state.
FIG. 6 is a plan view of the inner slide mold of the mold apparatus of FIG. 4 as viewed from the axial direction.
FIG. 7 is a sectional view taken along the line AA of FIG. 6;
8 is a perspective view of the first and second slide cores of the mold apparatus of FIG. 4, wherein FIG. 8 (A) is a perspective view of a second slide core, and FIG. FIG. 2 is a perspective view of a first slide core.
FIG. 9 is a perspective view of a center core of an inner slide mold of the mold apparatus of FIG. 4;
10 is a view of the moving state of the first and second slide cores adjacent to each other in the mold apparatus of FIG. 4 as viewed from the axial direction, and shows a position in a mold clamped state and a slide position in a mold open state. Is shown.
FIG. 11 is a partially enlarged view of the slide core of FIG. 10;
FIG. 12 shows a cam frame formed by the mold apparatus of FIG. 4 or a conventional mold apparatus, the inclination K of a cam groove with respect to the axis when the flank angle θ is used as a parameter, and the flank angle. FIG. 9 is a diagram showing a relationship between θ and an arc center angle ω of a slide core from which a cam groove can be removed. Note that ωa is a possible range when j = 4, and ωb is a possible range when j = 3.
FIG. 13 is a perspective view of another example of a cylindrical member formed by the mold apparatus of FIG. 4;
14 is a sectional view showing a modified example of a cam groove of a cam frame that can be formed by the mold apparatus of FIG. 4 and a cam follower fitted into the cam groove. FIG. 14A is a sectional view of the modified example. One of them is shown, and FIG. 14B shows another one of the modified examples.
FIG. 15 is a developed view of a lens barrel device, which is a cylindrical member device according to a third embodiment of the present invention, viewed from the inner peripheral side.
FIG. 16 is a developed view of a lens barrel device, which is a cylindrical member device according to a fourth embodiment of the present invention, viewed from an inner peripheral side.
FIG. 17 is a development view of a lens barrel device, which is a cylindrical member device according to a fifth embodiment of the present invention, viewed from an inner peripheral side.
FIG. 18 is a perspective view of an inner slide mold of a mold apparatus according to a sixth embodiment of the present invention.
FIG. 19 is a perspective view of a conventional lens frame device.
FIG. 20 is a developed view of the inner peripheral surface of the conventional lens barrel device of FIG. 19;
FIG. 21 is an enlarged sectional view of a cam groove and a cam follower provided in a cam frame of the conventional lens barrel device of FIG. 19;
[Explanation of symbols]
1, 32, 45 ... moving frame (second cylindrical member)
1a, 1b, 1c ... cam follower (guided part)
2, 45 ... cam frame (first tubular member, tubular member)
2a, 2b, 2c ... cam groove (guide portion)
2d, 31d, 41d, 45d ... parting line
3,52 ... Center core
4A, 4B, 4C, 4D, 53A, 53B, 53C, 53D: first slide core
4b: sliding contact surface (inclined surface)
4f, 5f, 53b, 54b ... convex part
5A, 5B, 5C, 5D, 54A, 54B, 54C, 54D ... second slide core
31 ... helicoid frame (first cylindrical member, cylindrical member)
31a, 31b, 31c ... female helicoid screw (guide part)
32... Moving frame (second cylindrical member, cylindrical member)
32a, 32b, 32c: Male helicoid (guided part)
41 ... fixed frame (tubular member)
41b: guide groove (circumferential groove)
42 ... rotating frame (tubular member)
42a: Projection (convex portion)
53g ... contact surface (inclined surface)
α… inclination angle (angle)
β… Inclination angle (angle)
γ ... tilt angle
C0… Center core axis
θ1, θ2 ... Frank angle
K: inclination of the cam groove with respect to the axial direction of the cylindrical member

Claims (20)

In a cylindrical member formed by a mold,
On the inner peripheral surface, N number of parting lines arranged in the circumferential direction along the axial direction of the cylindrical member,
M guide parts each arranged at least in one of the parting lines in the circumferential direction thereof,
Has,
N ≧ 8 and M ≧ 3
A cylindrical member characterized by the following. In a cylindrical member having a guide portion,
The guide portion is the cam groove or the female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle being θ2, and the cam groove or the female helicoid screw having an axial direction of the cylindrical member. Let K be the slope of
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25,
A cylindrical member including the guide portion described above. In a cylindrical member having a guide portion,
The guide portion is a cam groove or female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle of θ2, and the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member. If the slope is K,
16.5 ° ≦ θ1 ≦ 27.5 ° or 16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
A cylindrical member including the guide portion described above. In a cylindrical member having a guide portion,
The guide portion is a cam groove or female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle of θ2, and the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member. If the slope is K,
16.5 ° ≦ θ1 ≦ 26.5 ° or 16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
A cylindrical member including the guide portion described above. In a cylindrical member formed by a mold,
On the inner peripheral surface, there are N number of parting lines arranged in the circumferential direction along the axial direction of the cylindrical member, and at least one or more guide portions,
N ≧ 8
A cylindrical member characterized by the following. The guide portion is a cam groove or a female helicoid screw, and one of the flank surfaces has a flank angle of θ1, the other flank angle of θ2, and the guide portion has a cam groove inclined with respect to the axial direction of the cylindrical member. Is K,
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25,
6. The tubular member according to claim 5, wherein said guide portion is included. The guide portion is a cam groove or a female helicoid screw, and one of the flank surfaces has a flank angle of θ1, the other flank angle of θ2, and the guide portion has a cam groove inclined with respect to the axial direction of the cylindrical member. Is K,
16.5 ° ≦ θ1 ≦ 27.5 ° or 16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
6. The tubular member according to claim 5, wherein said guide portion is included. The guide portion is a cam groove or a female helicoid screw, and one flank angle of the flank surface is θ1, the other flank angle is θ2, and the guide portion is orthogonal to the cam groove in the longitudinal direction of the cylindrical member. Assuming that the inclination with respect to the line is K, 16.5 ° ≦ θ1 ≦ 26.5 ° or 16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
6. The tubular member according to claim 5, wherein said guide portion is included. In a tubular member device having a tubular member,
The mold is formed by a mold, and on the inner circumferential surface, N number of parting lines arranged in the circumferential direction along the axial direction, and M parts each straddling at least one of the parting lines and arranged in the circumferential direction. A first cylindrical member having a plurality of guide portions;
A second cylindrical member having a guided portion that is equally spaced in the circumferential direction of the outer peripheral surface and that is fitted into each of the guide portions and slidably in contact with the first cylindrical member so as to move within the inner circumference of the first cylindrical member; When,
Has,
N ≧ 8 and M ≧ 3
A tubular member device characterized by the following. The guide portion is any one of a cam groove, a female helicoid screw, a circumferential groove, and a circumferential rib. The cylindrical member device according to claim 9, wherein the cylindrical member device is one of a circumferential convex portion and a circumferential groove. The cylindrical member device according to claim 9, wherein the number of N is eight, and the number of M is three. The guide portion is a cam groove or female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle of θ2, and the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member. If the slope is K,
16.5 ° ≦ θ1 ≦ 28.0 ° or 16.5 ° ≦ θ2 ≦ 28.0 °
And
0.65 ≦ K ≦ 1.25
The cylindrical member device according to claim 9, wherein the guide portion is included. The guide portion is a cam groove or female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle of θ2, and the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member. If the slope is K,
16.5 ° ≦ θ1 ≦ 27.5 °
16.5 ° ≦ θ2 ≦ 27.5 °
And
0.70 ≦ K ≦ 1.25
The tubular portion device according to claim 9, wherein the guide portion is included. The guide portion is a cam groove or female helicoid screw, one of the flank surfaces having a flank angle of θ1 and the other flank angle of θ2, and the cam groove or the female helicoid screw with respect to the axial direction of the cylindrical member. If the slope is K,
16.5 ° ≦ θ1 ≦ 26.5 °
16.5 ° ≦ θ2 ≦ 26.5 °
And
0.80 ≦ K ≦ 1.25
The cylindrical member device according to claim 9, wherein the guide portion is included. For molding a cylindrical member having, on an inner peripheral surface, an even number of parting lines arranged in the circumferential direction along the axial direction, and a guide portion (cam groove) straddling at least one of the parting lines. Mold
Center core,
The j first first cores which are relatively movable in the axial direction and the radial direction in the direction of the angle α with respect to the axis center of the center core and are spaced apart from each other along the circumferential direction of the outer periphery of the center core. Slide core,
The first core, which is relatively movable in the axial direction and its radial direction in the direction of an angle β with respect to the axis center of the center core, is arranged between the first slide cores along the outer periphery of the center core. A second number of slide cores equal to the number of slide cores;
When the mold is closed, the first slide core and the second slide core are brought into contact with each other, and when the mold is opened, the first slide core and the second slide core are brought into contact with each other. An inclined surface for separating the slide core from the slide core, and in a plane orthogonal to the center core central axis, at an inclination angle γ with respect to a line orthogonal to the first slide core center line that intersects the center core central axis. Intersecting abutment surfaces,
And the relationship between the angles α, β, γ, and j is
β ≧ tan ⁻¹ {tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.1 °
And,
j ≧ 4
A mold characterized in that: The relationship between the angles α, β, γ is
tan ^-1 {tanα / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 0.175 ° ≦ β
≦ tan ^-1 {tan α / {cos (360 ° / 2j) −sin (360 ° / 2j) × tanγ} + 1.5 °
The mold according to claim 15, wherein: The angle α is
1.0 ° ≦ α ≦ 4.0 °
The mold according to claim 15, wherein: The angle α is
1.5 ° ≦ α ≦ 2.5 °
The mold according to claim 15, wherein: The angle γ is
0 ° ≦ γ ≦ 30 °
The mold according to claim 15, wherein: The angle γ is
5 ° ≦ γ ≦ 20 °
The mold according to claim 15, wherein:

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