JP5819150B2

JP5819150B2 - Injection mold and molded product

Info

Publication number: JP5819150B2
Application number: JP2011213017A
Authority: JP
Inventors: 孝幸藤戸
Original assignee: 盛岡セイコー工業株式会社
Priority date: 2011-09-28
Filing date: 2011-09-28
Publication date: 2015-11-18
Anticipated expiration: 2031-09-28
Also published as: JP2013071364A

Description

本発明は、射出成形用金型、及び成形品に関するものである。 The present invention relates to an injection mold and a molded product.

従来から、筒部、及び筒部における軸方向一端縁から径方向外側に向けて突設されたフランジ部を有する成形品を、射出成形により成形する方法として、例えば特許文献１に示されるような方法が知られている。
具体的に、特許文献１には、射出成形用金型において環状のキャビティの内側にディスク状のランナーが形成されるとともに、そのランナーの外縁と環状のキャビティの内縁とを全周に亘って繋ぐゲートが形成されており、さらに、ランナーに連通するスプルが雌型に形成されている。そして、このスプルからランナーに樹脂を注入すると、その樹脂が環状のゲートの全周からキャビティに流れ込み、キャビティに樹脂が充填されるようになっている。 Conventionally, as a method of molding a molded part having a cylindrical part and a flange part projecting radially outward from one axial end edge of the cylindrical part by injection molding, for example, as shown in Patent Document 1 The method is known.
Specifically, in Patent Document 1, a disk-shaped runner is formed inside an annular cavity in an injection mold, and the outer edge of the runner and the inner edge of the annular cavity are connected over the entire circumference. A gate is formed, and a sprue communicating with the runner is formed in a female shape. When resin is injected from the sprue into the runner, the resin flows into the cavity from the entire circumference of the annular gate, and the cavity is filled with the resin.

ところで、上述した筒部、及びフランジ部を有する成形品を成形する場合、フランジ部が厚かったり、筒部の軸長が長かったりすると、フランジ部の内周部分と筒部の根元部分との間でヒケが発生し易い。この場合には、筒部のうち軸方向に沿う先端側から根元側に向かうに従い内径が漸次広くなる等、先端側と根元側とで径差が発生する。
また、フランジ部が厚かったり、筒部の軸長が長かったりすると、樹脂充填の様相が悪く、樹脂材料がキャビティの全体に均一に行き渡り難くなるため、所望の形状の成形品を成形できないという問題がある。
そこで、これらの課題に対応するために、例えば、成形品全体での肉厚の均一化や、ゲート寸法の変更、成形収縮率の低い材料への変更、成形条件の変更等の対策が図られている。 By the way, when the molded part having the above-described cylinder part and flange part is formed, if the flange part is thick or the axial length of the cylinder part is long, the gap between the inner peripheral part of the flange part and the root part of the cylinder part It is easy to cause sink marks. In this case, a diameter difference occurs between the distal end side and the root side, such as the inner diameter gradually increases from the distal end side along the axial direction to the root side of the cylindrical portion.
Also, if the flange part is thick or the axial length of the cylinder part is long, the aspect of resin filling is poor, and the resin material is difficult to spread uniformly over the entire cavity, so that a molded product of a desired shape cannot be molded There is.
Therefore, in order to deal with these problems, for example, measures such as uniform thickness of the entire molded product, change of gate dimensions, change to a material having a low molding shrinkage rate, change of molding conditions, etc. are taken. ing.

特開２００８−４９７１１号公報JP 2008-49711 A

しかしながら、時計用歯車等の微小な部品を射出成形により成形する場合にあっては、製品形状が小さいため、未だ以下のような問題がある。
すなわち、上述した各種の対策のうち、例えば肉厚の均一化やゲート寸法の変更をする場合等には、自由度が小さく、所望の製品機能を有した上で、肉厚の均一化やゲート寸法の変更が難しいという問題がある。
また、上述した各種の対策のうち、例えば材料や成形条件の変更をする場合等には、変更による効果が小さく、改善が見込めないという問題がある。 However, when a minute part such as a timepiece gear is formed by injection molding, the product shape is small, and there are still the following problems.
That is, among the various measures described above, for example, when making the thickness uniform or changing the gate dimensions, etc., the degree of freedom is small and the desired product function is provided, and the thickness is made uniform and the gate is changed. There is a problem that it is difficult to change the dimensions.
In addition, among the various measures described above, for example, when changing materials and molding conditions, there is a problem that the effect of the change is small and improvement cannot be expected.

そこで本発明は、このような事情に考慮してなされたもので、製品機能を維持した上で、所望の形状に成形することが可能な射出成形用金型、及び成形品を提供することを目的とする。 Therefore, the present invention has been made in view of such circumstances, and provides an injection mold and a molded product that can be molded into a desired shape while maintaining the product function. Objective.

本発明の射出成形用金型は、重ね合わせた一対の型板の間に形成されたキャビティ内にゲートを介して樹脂材料が注入されることにより、筒部、及び前記筒部における軸方向一端縁から径方向外側に向けて突設されたフランジ部を有する成形品を成形するための射出成形用金型において、前記キャビティは、前記筒部を成形するための筒状の第１キャビティと、前記第１キャビティにおける軸方向一端側に連通し、前記フランジ部を成形するための環状の第２キャビティと、を有し、前記第２キャビティは、前記型板のうち、一方の型板に形成された凹部と、他方の型板における前記一方の型板との合わせ面と、で画成され、前記他方の型板の合わせ面において、内周部分には、前記凹部内に向けて突出するとともに、前記第１キャビティの全周を取り囲む突出成形部が形成されていることを特徴としている。 In the injection mold according to the present invention, a resin material is injected through a gate into a cavity formed between a pair of overlapped mold plates. In an injection mold for molding a molded product having a flange portion projecting radially outward, the cavity includes a cylindrical first cavity for molding the cylindrical portion, and the first An annular second cavity for molding the flange portion, and the second cavity is formed on one of the mold plates. The recess is defined by a mating surface of the other template with the one template, and in the mating surface of the other template, the inner peripheral portion protrudes into the recess, Of the first cavity It is characterized in that protruding molded portion surrounding the circumference.

この構成によれば、第２キャビティの内周部分、すなわち突出成形部と凹部との間隔を、第２キャビティの外周部分、すなわち他方の型板の合わせ面と凹部との間隔に比べて狭くすることができる。そのため、第２キャビティの内周部分には、突出成形部と凹部との間で成形されて、外周部分よりも薄肉とされた薄肉部が形成されることになる。
ここで、第１キャビティの全周に亘って突出成形部を形成することで、突出成形部と凹部との間隔が、第１キャビティの全周に亘って均一となる。
これにより、筒部となる第１キャビティ内とフランジ部となる第２キャビティ内の全体に樹脂材料を均一に充填でき、樹脂充填の様相を改善させることができるため、均一な収縮を促すことができる。また、樹脂材料が収縮する際に、第１キャビティと第２キャビティとの間でのヒケの発生を抑制することが可能になり、筒部の軸方向における径差を抑制できる。
その結果、成形品全体での肉厚の均一化や、ゲート寸法の変更、成形収縮率の低い材料への変更、成形条件の変更等、上述した各種の大幅な変更を伴うことなく、かつ製品機能を維持した上で、成形品を所望の形状に成形できる。 According to this configuration, the interval between the inner peripheral portion of the second cavity, that is, the protruding molded portion, and the concave portion is made narrower than the outer peripheral portion of the second cavity, that is, the interval between the mating surface of the other template and the concave portion. be able to. For this reason, a thin-walled portion that is molded between the protruding molded portion and the concave portion and is thinner than the outer peripheral portion is formed in the inner peripheral portion of the second cavity.
Here, by forming the projecting molded part over the entire circumference of the first cavity, the interval between the projecting molded part and the recess becomes uniform over the entire circumference of the first cavity.
As a result, the resin material can be uniformly filled in the entire first cavity serving as the cylinder portion and the second cavity serving as the flange portion, and the aspect of the resin filling can be improved. it can. Further, when the resin material contracts, it is possible to suppress the occurrence of sink marks between the first cavity and the second cavity, and the diameter difference in the axial direction of the cylindrical portion can be suppressed.
As a result, the product can be manufactured without the above-mentioned significant changes such as uniform thickness of the entire molded product, change of gate dimensions, change to a material with a low molding shrinkage rate, change of molding conditions, etc. The molded product can be molded into a desired shape while maintaining the function.

また、前記前記第１キャビティにおける径方向の間隔Ｄ１は、前記第２キャビティのうち前記突出成形部と前記凹部との間隔Ｄ２以上に設定されていることを特徴としている。
この構成によれば、筒部（第１キャビティ）の軸方向一端側と、フランジ部（第２キャビティ）の内周部分と、の間でのヒケを効果的に抑制できる。 Further, the radial distance D1 in the first cavity is set to be equal to or greater than the distance D2 between the protruding molded part and the recessed part in the second cavity.
According to this structure, the sink between the axial direction one end side of a cylinder part (1st cavity) and the inner peripheral part of a flange part (2nd cavity) can be suppressed effectively.

また、前記突出成形部には、前記キャビティ内に開口するゲートが形成されていることを特徴としている。
この構成によれば、突出成形部に開口するゲートを形成することで、成形後のゲート残り部が成形品の薄肉部に配置されることになる。そのため、ゲート残り部がフランジ部のから突出するのを抑えて、フランジ部の薄型化を図ることができる。 The protruding molded part is characterized in that a gate opening in the cavity is formed.
According to this configuration, by forming the gate opening in the protruding molded portion, the remaining gate portion after molding is disposed in the thin portion of the molded product. Therefore, it is possible to reduce the thickness of the flange portion by suppressing the remaining gate portion from protruding from the flange portion.

また、本発明の成形品は、上記本発明の射出成形用金型を用いて成形された成形品であって、前記フランジ部のうち、内周部分には、前記突出成形部と前記凹部との間で成形されて、外周部分よりも薄肉とされた薄肉部が形成され、前記薄肉部は、前記筒部における軸方向一端側を全周に亘って取り囲むように形成されていることを特徴としている。
この構成によれば、上記本発明の射出成形用金型を用いて成形されているため、筒部の軸方向での径差の発生を抑制して、所望の形状の成形品を提供できる。 Moreover, the molded product of the present invention is a molded product molded using the injection mold of the present invention described above, and of the flange portion, the inner peripheral portion includes the protruding molded portion and the concave portion. Forming a thin portion that is thinner than the outer peripheral portion, and the thin portion is formed so as to surround the one end side in the axial direction of the cylindrical portion over the entire circumference. It is said.
According to this structure, since it shape | molds using the injection mold of the said invention, generation | occurrence | production of the diameter difference in the axial direction of a cylinder part can be suppressed, and the molded product of a desired shape can be provided.

本発明に係る射出成形用金型によれば、製品機能を維持した上で、所望の形状に成形することが可能となる。
また、本発明に係る成形品によれば、筒部の軸方向での径差の発生を抑制して、所望の形状の成形品を提供できる。 The injection mold according to the present invention can be molded into a desired shape while maintaining the product function.
Moreover, according to the molded product which concerns on this invention, generation | occurrence | production of the diameter difference in the axial direction of a cylinder part can be suppressed, and the molded product of a desired shape can be provided.

本実施形態における成形品の斜視図である。It is a perspective view of the molded article in this embodiment. 図１のＡ−Ａ線に沿う断面図である。It is sectional drawing which follows the AA line of FIG. 図１のＡ−Ａ線に相当する射出成形用金型の断面図である。It is sectional drawing of the metal mold | die for injection molding corresponded to the AA line of FIG. 成形品の他の構成を示す斜視図である。It is a perspective view which shows the other structure of a molded article. 成形品の他の構成を示す斜視図である。It is a perspective view which shows the other structure of a molded article.

以下では、本発明の実施形態について添付図面を参照して説明する。
（成形品）
まず、後述する本実施形態の射出成形用金型２１で成形する成形品１について説明する。図１は成形品の斜視図であり、図２は図１のＡ−Ａ線に沿う断面図である。
図１に示すように、成形品１は、例えば機械式時計やクオーツ時計等に組み込まれる歯車であって、筒部２と、筒部２における軸方向一端縁（根元）から径方向の外側に向けて突設されたフランジ部３と、を有している。なお、筒部２及びフランジ部３は、それぞれの軸線を共通軸Ｏ上に配置させた状態で連設されている。以下、共通軸Ｏに沿った方向を単に「軸方向」、「軸方向」に直交する方向を単に「径方向」、「軸方向」周りの方向を単に「周方向」という。 Embodiments of the present invention will be described below with reference to the accompanying drawings.
(Molding)
First, the molded product 1 molded by an injection molding die 21 of the present embodiment to be described later will be described. FIG. 1 is a perspective view of a molded product, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.
As shown in FIG. 1, a molded product 1 is a gear incorporated in, for example, a mechanical timepiece, a quartz timepiece, or the like, and includes a cylindrical portion 2 and one axial edge (base) in the cylindrical portion 2 outward in the radial direction. And a flange portion 3 projecting toward it. In addition, the cylinder part 2 and the flange part 3 are connected in a state where the respective axis lines are arranged on the common axis O. Hereinafter, the direction along the common axis O is simply referred to as “axial direction”, the direction orthogonal to the “axial direction” is simply referred to as “radial direction”, and the direction around the “axial direction” is simply referred to as “circumferential direction”.

筒部２は、軸方向に沿って肉厚が一様な円筒状に形成されており、根元側の大径部５と、大径部５の軸方向他端側（先端側）に連設されて大径部５に対して縮径された小径部６と、を備えている。
フランジ部３の軸方向他端側（筒部２側）に位置する面（以下、表面７という）において、内周部分には外周部分に対して軸方向一端側に向けて窪んだ凹部８が形成されている。この凹部８は、筒部２（大径部５）の根元部を周方向の全周に亘って取り囲む環状の第１凹部１１と、第１凹部１１から径方向外側に向けて連設された第２凹部１２と、を備えている。第２凹部１２は、平面視で半円状に形成されるとともに、周方向に沿って間隔をあけて複数配列されている。したがって、フランジ部３のうち、内周部分は凹部８が形成された薄肉部１３を構成し、外周部分は薄肉部１３よりも厚い厚肉部１４を構成している。 The cylindrical portion 2 is formed in a cylindrical shape having a uniform thickness along the axial direction, and is connected to the large-diameter portion 5 on the root side and the other axial end side (tip side) of the large-diameter portion 5. And a small-diameter portion 6 that is reduced in diameter relative to the large-diameter portion 5.
On the surface (hereinafter referred to as surface 7) located on the other axial end side (cylinder portion 2 side) of the flange portion 3, the inner peripheral portion has a concave portion 8 that is recessed toward the one axial end side with respect to the outer peripheral portion. Is formed. The concave portion 8 is connected to the annular first concave portion 11 that surrounds the base portion of the cylindrical portion 2 (large-diameter portion 5) over the entire circumference in the circumferential direction, and is continuously provided from the first concave portion 11 toward the radially outer side. A second recess 12. The second recesses 12 are formed in a semicircular shape in plan view, and a plurality of second recesses 12 are arranged at intervals along the circumferential direction. Therefore, in the flange portion 3, the inner peripheral portion constitutes a thin portion 13 in which the concave portion 8 is formed, and the outer peripheral portion constitutes a thick portion 14 that is thicker than the thin portion 13.

そして、薄肉部１３において、各第２凹部１２の内側に位置する部分には、軸方向他端側に向けて突出するゲート残り部１５がそれぞれ形成されている。このゲート残り部１５における軸方向他端面は、フランジ部３の表面７に対して軸方向一端側に向けて窪んだ位置に配置されている。また、フランジ部３（厚肉部１４）の外周縁には、周方向の全周に亘って歯部１６が形成されている。これら歯部１６は、厚肉部１４よりも薄肉に形成されている。 And in the thin part 13, the gate remaining part 15 which protrudes toward the axial direction other end side is formed in the part located inside each 2nd recessed part 12, respectively. The other axial end surface of the remaining gate portion 15 is disposed at a position recessed toward the one axial end side with respect to the surface 7 of the flange portion 3. Moreover, the tooth | gear part 16 is formed in the outer periphery of the flange part 3 (thick part 14) over the perimeter of the circumferential direction. These tooth portions 16 are formed thinner than the thick portion 14.

（射出成形用金型）
次に、上述した成形品１を成形するための射出成形用金型２１について説明する。図３は、射出成形用金型の断面図であって、図１のＡ−Ａ線に相当する断面を示している。
図３に示すように、本実施形態における射出成形用金型２１は、固定側型板２２（他方の型板）と可動側型板２３（一方の型板）とを備えている。固定側型板２２及び可動側型板２３は、固定側型板２２を下に可動側型板２３を上にして上下に配置されており、これら固定側型板２２の上面（合わせ面）２４と可動側型板２３の下面（合わせ面）２５とが重ね合わされることで、両型板２２、２３の間に溶融樹脂（樹脂材料）Ｗが充填されるキャビティＣが形成される。また、図示しない昇降機構によって可動側型板２３を上下に昇降させることで、固定側型板２２と可動側型板２３とは上下方向に相対的に接近離間可能とされている。 (Injection mold)
Next, the injection mold 21 for molding the above-described molded product 1 will be described. FIG. 3 is a cross-sectional view of the injection mold, showing a cross-section corresponding to the line AA in FIG.
As shown in FIG. 3, the injection molding die 21 in the present embodiment includes a fixed-side template 22 (the other template) and a movable-side template 23 (one template). The fixed-side mold plate 22 and the movable-side mold plate 23 are arranged vertically with the fixed-side mold plate 22 facing down and the movable-side mold plate 23 facing up. And the lower surface (mating surface) 25 of the movable side mold plate 23 are overlapped to form a cavity C filled with a molten resin (resin material) W between both the mold plates 22 and 23. Further, the fixed side mold plate 22 and the movable side mold plate 23 can be relatively approached and separated in the vertical direction by moving the movable side mold plate 23 up and down by an elevating mechanism (not shown).

キャビティＣは、上述した成形品１を成形するための空間であり、成形品１のうち、筒部２を成形するための筒状の第１キャビティ３１と、第１キャビティ３１の上端部に連通し、フランジ部３を成形するための環状の第２キャビティ３２と、を有している。なお、各キャビティ３１，３２の軸線は、上述した共通軸Ｏ上に配置されており、共通軸Ｏに沿う可動側型板２３側（一端側）が上側、固定側型板２２側（他端側）が下側となっている。 The cavity C is a space for molding the molded product 1 described above, and communicates with the cylindrical first cavity 31 for molding the cylindrical portion 2 and the upper end of the first cavity 31 in the molded product 1. And an annular second cavity 32 for molding the flange portion 3. The axes of the cavities 31 and 32 are arranged on the common axis O described above, and the movable side mold plate 23 side (one end side) along the common axis O is the upper side, and the fixed side mold plate 22 side (the other end). Side) is on the bottom.

第１キャビティ３１は、固定側型板２２の上面２４に形成された固定側凹部３３と、固定側凹部３３の内側に配設されたピン部材３４と、で画成されている。
固定側凹部３３は、上下方向を軸方向とする円柱状に形成され、上方から下方に向かうに従い多段（２段）に縮径されている。 The first cavity 31 is defined by a fixed-side recess 33 formed on the upper surface 24 of the fixed-side template 22 and a pin member 34 disposed inside the fixed-side recess 33.
The fixed-side concave portion 33 is formed in a columnar shape having the vertical direction as an axial direction, and is reduced in diameter in multiple steps (two steps) from the upper side to the lower side.

ピン部材３４は、固定側凹部３３と同軸上に配置された円柱状とされ、上方から下方に向かうに従い多段（２段）に縮径されている。そして、ピン部材３４は、根元側（上端部）が可動側型板２３に固定され、先端側がキャビティＣ内を下方に向けて延在している。そして、ピン部材３４の先端面（下端面）は、固定側凹部３３の底壁３５に突き当たっている。すなわち、ピン部材３４は、キャビティＣにおける径方向中央部を上下方向に貫通するように配置されている。 The pin member 34 has a cylindrical shape arranged coaxially with the fixed-side concave portion 33 and is reduced in diameter to multiple stages (two stages) from the upper side to the lower side. The pin member 34 has a base side (upper end portion) fixed to the movable side mold plate 23 and a tip end side extending downward in the cavity C. The front end surface (lower end surface) of the pin member 34 abuts against the bottom wall 35 of the fixed side recess 33. That is, the pin member 34 is disposed so as to penetrate the radial center portion of the cavity C in the vertical direction.

そして、第１キャビティ３１のうち、固定側凹部３３の周壁部３６は、上側が上述した筒部２における大径部５の外周面を、下側が小径部６の外周面を成形し、底壁３５は筒部２における先端面をそれぞれ成形する。また、ピン部材３４は、上側が筒部２における大径部５の内周面を、下側が小径部６の内周面をそれぞれ成形する。 Of the first cavity 31, the peripheral wall portion 36 of the fixed-side concave portion 33 forms the outer peripheral surface of the large diameter portion 5 in the cylindrical portion 2 described above on the upper side and the outer peripheral surface of the small diameter portion 6 on the lower side. 35 respectively shape | molds the front end surface in the cylinder part 2. As shown in FIG. Further, the pin member 34 forms the inner peripheral surface of the large diameter portion 5 in the cylindrical portion 2 on the upper side and the inner peripheral surface of the small diameter portion 6 on the lower side.

第２キャビティ３２は、可動側型板２３の下面２５に形成された可動側凹部４１と、固定側型板２２の上面２４と、上述したピン部材３４と、で画成されている。
可動側凹部４１は、上下方向に沿う深さが固定側凹部３３よりも浅く、かつ、内径が固定側凹部３３よりも大きい円盤状に形成されており、固定側凹部３３と同軸上に配置されている。また、可動側凹部４１の周壁部４２のうち、上側には上述したフランジ部３の歯部１６を成形するための歯部成形部４３が形成されている。 The second cavity 32 is defined by a movable recess 41 formed on the lower surface 25 of the movable mold 23, the upper surface 24 of the fixed mold 22 and the pin member 34 described above.
The movable concave portion 41 is formed in a disk shape whose depth along the vertical direction is shallower than that of the fixed concave portion 33 and whose inner diameter is larger than that of the fixed concave portion 33, and is arranged coaxially with the fixed concave portion 33. ing. In addition, a tooth portion forming portion 43 for forming the tooth portion 16 of the flange portion 3 described above is formed on the upper side of the peripheral wall portion 42 of the movable side recessed portion 41.

固定側型板２２の上面２４は、上述した可動側凹部４１の頂壁４４と平行な平坦面であり、頂壁４４との間に上述したフランジ部３の厚み分の間隔を有している。また、固定側型板２２の上面２４のうち、可動側凹部４１の外周に相当する部分には、可動側凹部４１内を臨むように上方に向けて突出する環状突部４５が形成されている。環状突部４５の外周面は、可動側凹部４１における周壁部４２の下側に摺接している。そして、環状突部４５の上端面と可動側凹部４１の頂壁４４との間は、上述した歯部１６の厚み分の間隔を有している。 The upper surface 24 of the fixed-side template 22 is a flat surface parallel to the top wall 44 of the movable recess 41 described above, and has an interval corresponding to the thickness of the flange portion 3 described above between the top wall 44. . In addition, an annular protrusion 45 that protrudes upward so as to face the inside of the movable side recess 41 is formed on a portion of the upper surface 24 of the fixed side template 22 corresponding to the outer periphery of the movable side recess 41. . The outer peripheral surface of the annular protrusion 45 is in sliding contact with the lower side of the peripheral wall portion 42 in the movable side recess 41. The gap between the upper end surface of the annular protrusion 45 and the top wall 44 of the movable side recess 41 is equal to the thickness of the tooth portion 16 described above.

ここで、固定側型板２２の上面２４の内周部分、すなわち固定側凹部３３の周囲に相当する部分には、可動側凹部４１内を臨むように上方へ向けて突出する突出成形部５１が形成されている。この突出成形部５１は、上述したフランジ部３のうち凹部８内に入り込む部分であり、固定側凹部３３の全周を取り囲む環状の第１突出部５２と、第１突出部５２から径方向の外側に向けて連設された第２突出部５３と、を有している。突出成形部５１の上端面と可動側凹部４１の頂壁４４との間は、上述した薄肉部１３の厚み分の間隔を有している。 Here, on the inner peripheral portion of the upper surface 24 of the fixed-side template 22, that is, the portion corresponding to the periphery of the fixed-side concave portion 33, a protruding molding portion 51 that protrudes upward so as to face the movable-side concave portion 41. Is formed. The protruding molded portion 51 is a portion that enters the recess 8 in the flange portion 3 described above, and has an annular first protruding portion 52 that surrounds the entire circumference of the fixed-side recessed portion 33, and a radial direction from the first protruding portion 52. And a second projecting portion 53 provided continuously toward the outside. Between the upper end surface of the protruding molded part 51 and the top wall 44 of the movable side recessed part 41, there is an interval corresponding to the thickness of the thin part 13 described above.

第２突出部５３は、平面視で半円状に形成されるとともに、周方向に沿って間隔をあけて複数配列されている。また、突出成形部５１のうち、各第２突出部５３に相当する部分には、キャビティＣ内に開口するゲート開口５５を有するピンゲート５６がそれぞれ形成されている。各ピンゲート５６は、固定側型板２２を上下方向に沿って貫通しており、上方から下方に向かうに従い漸次拡径されている。そして、ピンゲート５６のゲート開口５５は、可動側凹部４１における頂壁４４の内周部分と上下方向で対向している。 The second projecting portions 53 are formed in a semicircular shape in plan view, and a plurality of second projecting portions 53 are arranged at intervals along the circumferential direction. In addition, pin gates 56 each having a gate opening 55 that opens into the cavity C are formed in portions corresponding to the respective second protrusions 53 in the protrusion molding portion 51. Each pin gate 56 penetrates the fixed side mold plate 22 in the vertical direction, and the diameter is gradually increased from the upper side to the lower side. The gate opening 55 of the pin gate 56 opposes the inner peripheral portion of the top wall 44 in the movable side recess 41 in the vertical direction.

そして、第２キャビティ３２のうち、固定側型板２２の上面２４がフランジ部３の表面７を、可動側凹部４１の周壁部４２（歯部成形部４３）がフランジ部３の歯部１６を、可動側凹部４１の頂壁４４がフランジ部３の軸方向一端側（筒部２とは反対側）に位置する面（以下、裏面９（図１参照）という）を、それぞれ成形する。そして、本実施形態では、突出成形部５１と可動側凹部４１の頂壁４４との間で、フランジ部３の薄肉部１３を成形する。 Of the second cavities 32, the upper surface 24 of the fixed-side mold plate 22 is the surface 7 of the flange portion 3, and the peripheral wall portion 42 (tooth portion molding portion 43) of the movable-side recess 41 is the tooth portion 16 of the flange portion 3. The surface (hereinafter referred to as back surface 9 (see FIG. 1)) where the top wall 44 of the movable-side recess 41 is located on one axial end side (the opposite side to the tube portion 2) of the flange portion 3 is formed. And in this embodiment, the thin part 13 of the flange part 3 is shape | molded between the protrusion shaping | molding part 51 and the top wall 44 of the movable side recessed part 41. FIG.

なお、固定側凹部３３の上端部において、周壁部３６とピン部材３４との径方向に沿う間隔Ｄ１（筒部２における基端部の径方向に沿う厚さ）は、突出成形部５１の上端面と可動側凹部４１の頂壁４４との上下方向に沿う間隔Ｄ２（薄肉部１３の厚さ）と等しく設定されていることが好ましい（Ｄ１＝Ｄ２）。本実施形態では製品形状の制約上、周壁部３６とピン部材３４との径方向に沿う間隔Ｄ１は、突出成形部５１の上端面と可動側凹部４１の頂壁４４との上下方向に沿う間隔Ｄ２以上になっている（Ｄ１≧Ｄ２）。 Note that, in the upper end portion of the fixed-side concave portion 33, the distance D <b> 1 along the radial direction between the peripheral wall portion 36 and the pin member 34 (the thickness along the radial direction of the base end portion in the cylindrical portion 2) is the top of the protruding molding portion 51. It is preferable that the distance D2 (the thickness of the thin portion 13) along the vertical direction between the end surface and the top wall 44 of the movable-side concave portion 41 is set to be equal (D1 = D2). In the present embodiment, the distance D1 along the radial direction between the peripheral wall portion 36 and the pin member 34 is the distance along the vertical direction between the upper end surface of the protruding molded portion 51 and the top wall 44 of the movable-side concave portion 41 due to product shape constraints. D2 or more (D1 ≧ D2).

（射出成形方法）
次に、上述した射出成形用金型２１を用いて成形品１を製造する方法について説明する。
はじめに、図示しない昇降機構によって可動側型板２３を下降させ、可動側型板２３の下面２５を固定側型板２２の上面２４に当接させ、射出成形用金型２１を閉じておく。続いて、図示しない射出装置によって溶融樹脂Ｗを各ピンゲート５６内に注入する。ピンゲート５６内に注入された溶融樹脂Ｗは、各ゲート開口５５を通じてキャビティＣ（第２キャビティ３２）内に注入される。すると、キャビティＣ内に注入された溶融樹脂Ｗは、各ゲート開口５５から径方向の全域に行き渡り、第２キャビティ３２内の全体に充填されるとともに、第１キャビティ３１の上端部から第１キャビティ３１内に流入し、第１キャビティ３１内の全体に充填される。
なお、キャビティＣ内の気体（エア）は、溶融樹脂Ｗの注入に伴って図示しないガス抜き溝を通って射出成形用金型２１の外部に排出される。 (Injection molding method)
Next, a method for manufacturing the molded product 1 using the above-described injection mold 21 will be described.
First, the movable side mold plate 23 is lowered by an elevating mechanism (not shown), the lower surface 25 of the movable side mold plate 23 is brought into contact with the upper surface 24 of the fixed side mold plate 22, and the injection mold 21 is closed. Subsequently, molten resin W is injected into each pin gate 56 by an injection device (not shown). The molten resin W injected into the pin gate 56 is injected into the cavity C (second cavity 32) through each gate opening 55. Then, the molten resin W injected into the cavity C reaches the entire radial direction from each gate opening 55 and fills the entire inside of the second cavity 32, and from the upper end of the first cavity 31 to the first cavity. 31 flows into the interior of the first cavity 31 and is filled.
The gas (air) in the cavity C is discharged to the outside of the injection mold 21 through a gas vent groove (not shown) as the molten resin W is injected.

そして、充填した溶融樹脂Ｗが固化した後、固定側型板２２と可動側型板２３とを相対的に離間させる離型を行う。つまり、可動側型板２３を図示しない昇降機構によって上昇させ、可動側型板２３を固定側型板２２から離間させる。その後、例えば図示しないエジェクターピンによる突き出し等によって、成形品１を可動側型板２３から取り外すことで、図１，２に示す成形品１を得ることができる。 Then, after the filled molten resin W is solidified, a mold release for relatively separating the fixed side mold plate 22 and the movable side mold plate 23 is performed. That is, the movable side mold plate 23 is raised by an elevating mechanism (not shown), and the movable side mold plate 23 is separated from the fixed side mold plate 22. Thereafter, the molded product 1 shown in FIGS. 1 and 2 can be obtained by removing the molded product 1 from the movable side mold plate 23 by, for example, ejecting by an ejector pin (not shown).

なお、上述した射出成形用金型２１で成形された成形品１には、図１，２に示すように、フランジ部３において筒部２を全周に亘って取り囲む凹部８が形成されるとともに、凹部８のうち第２凹部１２の内側に位置する部分には、ゲート残り部１５が形成されることとなる。 In addition, as shown in FIGS. 1 and 2, the molded product 1 molded with the above-described injection molding die 21 is provided with a recess 8 that surrounds the entire cylindrical portion 2 in the flange portion 3. The remaining gate portion 15 is formed in a portion of the recess 8 located inside the second recess 12.

このように、本実施形態では、固定側型板２２の上面２４のうち内周部分に、可動側凹部４１内に向けて突出するとともに、第１キャビティ３１の全周を取り囲む突出成形部５１を形成する構成とした。
この構成によれば、第１キャビティ３１の全周に亘って突出成形部５１を形成することで、突出成形部５１と可動側凹部４１との間隔が、第１キャビティ３１の全周に亘って均一となる。
これにより、第１キャビティ３１内と第２キャビティ３２内の全体に溶融樹脂Ｗを均一に充填でき、樹脂充填の様相を改善させることができるため、均一な収縮を促すことができる。また、溶融樹脂Ｗが収縮する際に、第１キャビティ３１と第２キャビティ３２との間でのヒケの発生を抑制することが可能になり、筒部２の軸方向における径差を抑制できる。
したがって、成形品全体での肉厚の均一化や、ゲート寸法の変更、成形収縮率の低い材料への変更、成形条件の変更等、上述した各種の大幅な変更を伴うことなく、かつ製品機能を維持した上で、成形品１を所望の形状に成形できる。この場合、突出成形部５１を形成する簡素な構成のため、時計用歯車等の微小な部品であっても、比較的容易に高精度な成形品１を成形できる。 Thus, in the present embodiment, the protruding molding portion 51 that protrudes toward the inside of the movable-side recess 41 on the inner peripheral portion of the upper surface 24 of the fixed-side template 22 and surrounds the entire circumference of the first cavity 31 is provided. It was set as the structure to form.
According to this configuration, by forming the protruding molded portion 51 over the entire circumference of the first cavity 31, the interval between the protruding molded portion 51 and the movable-side recess 41 extends over the entire circumference of the first cavity 31. It becomes uniform.
Thereby, the molten resin W can be uniformly filled in the first cavity 31 and the entire second cavity 32, and the aspect of resin filling can be improved, so that uniform shrinkage can be promoted. Further, when the molten resin W contracts, it is possible to suppress the occurrence of sink marks between the first cavity 31 and the second cavity 32, and the diameter difference in the axial direction of the cylindrical portion 2 can be suppressed.
Therefore, the product functions without the above-mentioned significant changes such as uniform thickness of the entire molded product, change of gate dimensions, change to a material with low molding shrinkage ratio, change of molding conditions, etc. In addition, the molded product 1 can be molded into a desired shape. In this case, because of the simple configuration for forming the protruding molding portion 51, even a minute part such as a timepiece gear can mold the molded article 1 with high accuracy relatively easily.

しかも、本実施形態では、固定側凹部３３の上端部において、周壁部３６とピン部材３４との径方向に沿う間隔Ｄ１が、突出成形部５１の上端面と可動側凹部４１の頂壁４４との上下方向に沿う間隔Ｄ２以上に設定されているため、第１キャビティ３１と第２キャビティ３２との間でのヒケを効果的に抑制できる。
また、本実施形態では、突出成形部５１にゲート開口５５を形成することで、ゲート残り部１５が成形品１の第２凹部１２内（薄肉部１３上）に配置されることになる。そのため、ゲート残り部１５がフランジ部３の表面７から突出することがなく、フランジ部３の薄型化を図ることができる。 Moreover, in this embodiment, the distance D1 along the radial direction between the peripheral wall portion 36 and the pin member 34 at the upper end portion of the fixed-side recess portion 33 is such that the upper end surface of the projecting molding portion 51 and the top wall 44 of the movable-side recess portion 41. Therefore, the sink between the first cavity 31 and the second cavity 32 can be effectively suppressed.
In the present embodiment, the gate opening 55 is formed in the protruding molded part 51, so that the remaining gate part 15 is arranged in the second recess 12 (on the thin part 13) of the molded product 1. Therefore, the gate remaining portion 15 does not protrude from the surface 7 of the flange portion 3, and the flange portion 3 can be thinned.

以上、本発明の技術範囲は上述した実施の形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。
例えば、上述した実施形態では、フランジ部３の外周縁に歯部１６を有する成形品１に本発明を適用した場合について説明したが、これに限らず、図４に示すように、筒部２及びフランジ部３を有していれば、種々の形状に採用することができる。
また、上述した実施形態では、フランジ部３の表面７側に凹部８を形成する構成について説明したが、これに限らず、図５に示すように、フランジ部３の裏面９側に凹部８を形成する構成にしても構わない。 As described above, the technical scope of the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the present invention is applied to the molded product 1 having the tooth portion 16 on the outer peripheral edge of the flange portion 3 has been described. However, the present invention is not limited thereto, and as shown in FIG. And if it has the flange part 3, it can employ | adopt as a various shape.
In the above-described embodiment, the configuration in which the concave portion 8 is formed on the surface 7 side of the flange portion 3 has been described. However, the present invention is not limited thereto, and the concave portion 8 is provided on the back surface 9 side of the flange portion 3 as shown in FIG. You may make it the structure to form.

また、上述した実施形態では、突出成形部５１の各第２突出部５３にゲート開口５５を形成した場合について説明したが、これに限らず、ゲート開口５５の位置や数量は適宜変更が可能である。
また、上述した実施形態では、一方の型板を可動側型板２３、他方の型板を固定側型板２２として説明したが、これとは逆に、一方の型板を固定側型板、他方の型板を可動側型板としても構わない。 In the above-described embodiment, the case where the gate openings 55 are formed in the respective second protrusions 53 of the protrusion molding part 51 has been described. However, the present invention is not limited to this, and the position and quantity of the gate openings 55 can be changed as appropriate. is there.
In the above-described embodiment, one mold plate is described as the movable mold plate 23 and the other mold plate is the fixed mold plate 22. On the contrary, one mold plate is fixed as the fixed mold plate, The other template may be a movable template.

さらに、上述した実施形態では、ピンゲート５６を用いて溶融樹脂Ｗを注入する構成について説明したが、これに限らず、サイドゲートやディスクゲート等を用いても構わない。特に、ディスクゲートを採用することで、溶融樹脂Ｗが周方向の全周から一様に充填されるため、キャビティＣ内の全体に確実に溶融樹脂Ｗを充填できる。
また、上述した実施形態では、時計用の歯車を成形する場合について説明したが、これに限らず、種々の部品を成形することが可能である。 Further, in the above-described embodiment, the configuration in which the molten resin W is injected using the pin gate 56 is described. However, the configuration is not limited thereto, and a side gate, a disk gate, or the like may be used. In particular, by adopting a disk gate, the molten resin W is uniformly filled from the entire circumference in the circumferential direction, so that the entire inside of the cavity C can be reliably filled with the molten resin W.
In the above-described embodiment, the case of forming a timepiece gear has been described. However, the present invention is not limited to this, and various parts can be formed.

１…成形品２…筒部３…フランジ部３１…第１キャビティ３２…第２キャビティ２２…固定側型板（他方の型板）２３…可動側型板（一方の型板）２４…上面（合わせ面）４１…可動側凹部（凹部）５６…ピンゲート（ゲート） DESCRIPTION OF SYMBOLS 1 ... Molded product 2 ... Cylindrical part 3 ... Flange part 31 ... 1st cavity 32 ... 2nd cavity 22 ... Fixed side template (the other template) 23 ... Movable side template (one template) 24 ... Upper surface ( 41) Movable side recess (recess) 56 ... Pin gate (gate)

Claims

A resin material is injected through a gate into a cavity formed between a pair of overlapped templates so that the cylindrical portion and one axial end edge of the cylindrical portion protrude radially outward. In an injection mold for molding a molded product having a flange portion,
The cavity includes a cylindrical first cavity for molding the cylindrical portion,
An annular second cavity that communicates with one end side in the axial direction of the first cavity and molds the flange portion;
The second cavity is defined by a recess formed in one of the template plates and a mating surface of the other template with the one template plate,
On the mating surface of the other template, an inner peripheral portion is formed with a protruding molded portion that protrudes into the recess and surrounds the entire circumference of the first cavity ,
An annular protrusion is formed on the outer periphery of the recess of the second cavity so as to protrude upward so as to face the interior of the recess, so that the outer peripheral edge of the flange portion extends over the entire circumference. , injection mold, characterized in Rukoto thin tooth portion is formed than the outer peripheral portion.

2. The injection molding gold according to claim 1, wherein a radial distance D <b> 1 in the first cavity is set to be equal to or greater than a distance D <b> 2 between the protruding molded part and the recessed part in the second cavity. Type.

The injection molding die according to claim 1 or 2, wherein a gate opening in the cavity is formed in the protruding molding part.

A molded product molded using the injection mold according to claim 1,
Of the flange portion, an inner peripheral portion is formed between the protruding molded portion and the concave portion, and a thin portion formed thinner than the outer peripheral portion is formed,
The thin-walled portion is formed so as to surround one end side in the axial direction of the cylindrical portion over the entire circumference ,
A molded product characterized in that the outer peripheral edge of the flange part is provided with a tooth part formed thinner than the outer peripheral part over the entire circumference in the circumferential direction .