JP2805365B2 - Injection molded body with rib for reinforcement - Google Patents
Injection molded body with rib for reinforcementInfo
- Publication number
- JP2805365B2 JP2805365B2 JP153090A JP153090A JP2805365B2 JP 2805365 B2 JP2805365 B2 JP 2805365B2 JP 153090 A JP153090 A JP 153090A JP 153090 A JP153090 A JP 153090A JP 2805365 B2 JP2805365 B2 JP 2805365B2
- Authority
- JP
- Japan
- Prior art keywords
- molded body
- reinforcing ribs
- reinforcing rib
- rib
- injection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、例えば自動車用ホイールキャプ、インスト
ルメントパネル、インナートリム、および事務機器・家
電のハウジング等に用いられる成形体のように単数また
は複数の補強用リブを有する射出成形体に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to one or more molded articles used for, for example, wheel caps for automobiles, instrument panels, inner trims, and housings of office equipment and home appliances. And an injection-molded article having a reinforcing rib.
［従来技術］ 従来の補強用リブ付射出成形体は、第３図（ａ）に示
されるように成形体本体４から補強用リブ１が直接突出
した形状となっている。[Prior Art] A conventional injection-molded article with reinforcing ribs has a shape in which the reinforcing ribs 1 directly protrude from the molded body 4 as shown in FIG.
［発明が解決しようとする課題］ しかしながら、上記従来の補強用リブ付射出成形体に
は次のような問題が残されている。[Problems to be Solved by the Invention] However, the following problems remain in the conventional injection-molded article with a reinforcing rib.
（１）補強用リブと成形体本体４の交差部は、実質的に
肉厚状態となり、冷却固化時の熱収縮量が厚肉部に集中
する。このため第３図（ｂ）に示されるように、成形体
本体４表面に、所謂「ヒケ」と称される窪みが形成され
やすい。(1) The intersection between the reinforcing rib and the molded body 4 is substantially thick, and the heat shrinkage during cooling and solidification is concentrated on the thick part. For this reason, as shown in FIG. 3 (b), a depression called so-called “sink” is easily formed on the surface of the molded body 4.
（２）上記「ヒケ」を防止するためには、補強用リブ１
の幅を小さくしなければならず、このために次のような
ことが問題となる。(2) In order to prevent the above “sink”, a reinforcing rib 1
Must be reduced, which causes the following problems.
補強用リブ１の上端に樹脂を流動させるためには補
強用リブ１の上端の幅を1mm以上に保つことが好まし
く、そのためには補強用リブ１の抜き勾配を小さく（0.
5度程度）して、補強用リブ１の幅を確保せねばなら
ず、成形体が離型しにくい形状となる。In order to allow the resin to flow to the upper end of the reinforcing rib 1, the width of the upper end of the reinforcing rib 1 is preferably maintained at 1 mm or more.
(About 5 degrees), and the width of the reinforcing ribs 1 must be secured, so that the molded body has a shape that is difficult to release.
補強用リブ１の幅と抜き勾配が小さいため、補強用
リブ１の高さが制限されるので、高い補強効果が得にく
く、多数の補強用リブ１を設けることが必要となり、成
形時に大きな射出圧が必要となり、成形が難しくなる。Since the width and draft of the reinforcing ribs 1 are small, the height of the reinforcing ribs 1 is limited, so that it is difficult to obtain a high reinforcing effect. Pressure is required, making molding difficult.
また、多数の補強用リブ１を成形するには、成形型も
多数の入駒を組み合わせた構造の金型となり、金型の製
作工程数が多くなり高価な金型になるばかりでなく、型
の組立毎に入駒間の隙間が変わり、安定した寸法精度の
成形体が得られない。Further, in order to form a large number of reinforcing ribs 1, a molding die is also a mold having a structure in which a large number of input pieces are combined. The gap between the input pieces changes with each assembly, and a molded body with stable dimensional accuracy cannot be obtained.
［問題を解決するための手段］ 前記問題を解決するために、本発明で講じられた手段
を、本発明の一実施例に対応する第１図（ａ）〜（ｄ）
で説明すると、本発明に係る補強用リブ付射出成形体
は、補強用リブ１と成形体本体４との交差部に、補強用
リブ１より幅広で中空の台部２が一体に形成されている
ことを特徴とするものである。[Means for Solving the Problems] In order to solve the above problems, the measures taken in the present invention are replaced with FIGS. 1 (a) to 1 (d) corresponding to an embodiment of the present invention.
In the injection molded article with a reinforcing rib according to the present invention, a hollow base 2 wider and hollower than the reinforcing rib 1 is integrally formed at the intersection of the reinforcing rib 1 and the molded body 4. It is characterized by having.
［作用］ 本発明には、以下のような作用がある。[Operation] The present invention has the following operation.
成形体本体４と補強用リブ１の交差部に中空の台部２
を設けて、厚肉となる成形体本体４と補強用リブ１との
交差部の樹脂厚を薄くしたことにより、冷却固化時の樹
脂の熱収縮量の集中を防ぐとともに、中空部３を成形す
る中空部成形流体が樹脂をキャビティ５の面に押圧しな
がら、樹脂を冷却固化させるため、ヒケを容易に防止す
ることができる。At the intersection of the molded body 4 and the reinforcing rib 1, a hollow base 2
The thickness of the resin at the intersection of the thick molded body 4 and the reinforcing rib 1 is reduced to prevent concentration of heat shrinkage of the resin during cooling and solidification, and to form the hollow portion 3. Since the resin is cooled and solidified while the resin is pressed against the surface of the cavity 5, sink marks can be easily prevented.
台部２の幅は補強用リブ１より広いため、中空部３に
よる強度の低下が生じないことと、ヒケが発生しなくな
ることにより、補強用リブ１の形状制限を取り除くこと
ができるため、多数の小型の補強用リブ１を成形体本体
４に設ける代わりに、少数の大型の補強用リブ１で大き
な補強効果を得ることができる。Since the width of the base portion 2 is wider than the reinforcing ribs 1, the strength is not reduced by the hollow portions 3, and since the sink is not generated, the shape limitation of the reinforcing ribs 1 can be removed. Instead of providing the small reinforcing ribs 1 on the molded body 4, a large reinforcing effect can be obtained with a small number of large reinforcing ribs 1.
また、大型の補強用リブ１を設けることができるの
で、補強用リブ１の厚さと抜き勾配を十分に取ることが
できるため、射出成形時の溶融樹脂の流動に要する射出
圧が低くて済み、型内樹脂圧が低下するので、成形体の
離型も容易になる。In addition, since the large reinforcing ribs 1 can be provided, the thickness and draft angle of the reinforcing ribs 1 can be sufficiently taken, so that the injection pressure required for the flow of the molten resin during injection molding can be reduced. Since the resin pressure in the mold is reduced, the molded article is easily released from the mold.
更に、補強用リブの１の強度・剛性向上にともない、
少数の補強用リブ１で同等以上の強度・剛性向上効果が
得られるため、型の構造がシンプルになり、製作及び組
立て工数が減り、型の組立時におきる寸法のばらつきが
生じなくなる。Furthermore, with the improvement of the strength and rigidity of the reinforcing rib 1,
Since a small number of reinforcing ribs 1 can achieve the same or higher strength / rigidity improvement effect, the structure of the mold is simplified, the number of manufacturing and assembling steps is reduced, and the dimensional variation that occurs when assembling the mold does not occur.
［実施例］ 第１図（ａ）〜（ｄ）を用いて、本発明の補強用リブ
付射出成形体を説明する。Example An injection-molded article with a reinforcing rib of the present invention will be described with reference to FIGS. 1 (a) to 1 (d).
本発明の補強用リブ付射出成形体は、成形体本体４に
補強用リブ１が成形されており、当該補強用リブ１と成
形体本体４の交差部に中空部３を有する台部２が設けら
れている一体構造の射出成形体である。In the injection-molded article with reinforcing ribs of the present invention, a reinforcing rib 1 is formed on a molded body 4, and a base 2 having a hollow portion 3 at an intersection of the reinforcing rib 1 and the molded body 4 is formed. It is an injection-molded body of an integral structure provided.
補強用リブ１の抜き勾配は１度以上が好ましく、補強
用リブ１の幅は成形体本体４の厚さの0.7倍以上にする
ことができる。補強用リブ１の幅を広く取ることができ
るので、補強用リブ１の高さを高くすることができ、よ
り強固な補強が可能となる。また、その数は第１図
（ａ），（ｂ）に示すように単数であっても良いし、第
１図（ｃ），（ｄ）に示すように、複数であっても良
い。The draft of the reinforcing rib 1 is preferably 1 degree or more, and the width of the reinforcing rib 1 can be 0.7 times or more the thickness of the molded body 4. Since the width of the reinforcing ribs 1 can be made wider, the height of the reinforcing ribs 1 can be increased, and stronger reinforcement can be achieved. Further, the number may be singular as shown in FIGS. 1 (a) and 1 (b), or may be plural as shown in FIGS. 1 (c) and 1 (d).
台部２は、半円形あるいは台形の中空部３を有してい
る部分であり、その形状は半円あるいは台形である。ま
た、台部２の厚さｄは、成形体本体４の厚さの1.5〜４
倍、台部２の幅ｗは、成形体本体４の厚さの２〜８倍で
あることが好ましい。半円形の場合もほぼ同様の範囲が
好ましい。The base portion 2 is a portion having a semicircular or trapezoidal hollow portion 3, and has a semicircular or trapezoidal shape. The thickness d of the base 2 is 1.5 to 4 times the thickness of the molded body 4.
The width w of the base 2 is preferably 2 to 8 times the thickness of the molded body 4. In the case of a semicircle, substantially the same range is preferable.
中空部３の容積率は、中空部３を含む中空型物の全体
積において中空部３の容積が占める割合を言い、使用す
る樹脂の比容積変化によって変るが、５〜15％である。
このとき、容積率が下限以下では有効な中空部３の形成
が難しくなり、上限を越えると中空部３を形成する前に
充填される樹脂の流れが乱れ、均一な樹脂の充填が難し
くなる。The volume ratio of the hollow portion 3 refers to a ratio occupied by the volume of the hollow portion 3 in the entire volume of the hollow mold including the hollow portion 3 and varies from 5 to 15% depending on the specific volume change of the resin used.
At this time, if the volume ratio is lower than the lower limit, it is difficult to form an effective hollow portion 3. If the volume ratio exceeds the upper limit, the flow of the resin to be filled before forming the hollow portion 3 is disturbed, and it is difficult to uniformly fill the resin.
更に、第２図に補強用リブ付射出成形体の一成形例を
示す。Further, FIG. 2 shows an example of molding of an injection molded article with a reinforcing rib.
キャビティ５内の所望の位置に、キャビティ５内への
溶融樹脂注入位置から補助室７方向へ延在させて補強用
リブ成形のための溝である溝部６を成形する。A groove 6 is formed at a desired position in the cavity 5 so as to extend from the molten resin injection position into the cavity 5 toward the auxiliary chamber 7 to form a groove for forming a reinforcing rib.
キャビティ５内への溶融樹脂の注入時もしくは注入後
に中空部成形流体を圧入したとき、溝部６の溶融樹脂は
補助室７へ流出し、溝部６に沿って中空部３を成形する
ことができる。When the hollow resin is injected into the cavity 5 or after injection of the molten resin into the cavity 5, the molten resin in the groove 6 flows out to the auxiliary chamber 7, and the hollow 3 can be formed along the groove 6.
上記のようにして中空部３を成形した後は、中空部成
形流体の圧力を維持したままキャビティ５内の溶融樹脂
を冷却固化させ、その後中空部３内の中空部成形流体を
排出してから型を開いて成形体を取り出す。After molding the hollow portion 3 as described above, the molten resin in the cavity 5 is cooled and solidified while maintaining the pressure of the hollow portion forming fluid, and then the hollow portion forming fluid in the hollow portion 3 is discharged. Open the mold and remove the compact.
キャビティ５内の溝部６の数を変えることによって、
必要な数の補強用リブ１を得ることができる。By changing the number of grooves 6 in the cavity 5,
The required number of reinforcing ribs 1 can be obtained.
［発明の効果］ 本発明の補強用リブ付射出成形体は、以上説明した通
りのものであり、次の効果を奏するものである。[Effects of the Invention] The injection-molded article with reinforcing ribs of the present invention is as described above, and has the following effects.
成形体本体と補強用リブの交差部に中空部を設けるこ
とによりヒケを防止することができるため、表面外観に
優れた薄肉の補強用リブ付射出成形体を得ることができ
る。By providing a hollow portion at the intersection of the molded body and the reinforcing rib, sink marks can be prevented, so that a thin-walled injection molded product with a reinforcing rib having excellent surface appearance can be obtained.
また、補強用リブの強度、剛性向上にともない、成形
体本体に設けられる補強用リブの数を減らすことができ
るため、型の構造が簡単になり、安定した寸法制度の成
形体を得ることができる。In addition, as the strength and rigidity of the reinforcing ribs are improved, the number of reinforcing ribs provided on the molded body can be reduced, so that the structure of the mold is simplified, and a molded body having a stable dimensional accuracy can be obtained. it can.
また、補強用リブの厚さと抜き勾配を十分にとること
ができるため、射出成形時の流動性が向上し、離型が容
易になるため、作業能率が向上し、生産性が向上する。In addition, since the thickness and draft of the reinforcing rib can be sufficiently set, the fluidity during injection molding is improved, and the mold release is facilitated, so that work efficiency is improved and productivity is improved.
第１図（ａ）〜（ｄ）は、補強用リブ付射出成形体、第
２図は、成形例、第３図（ａ），（ｂ）は、従来の補強
用リブ付成形体を示す。 １……補強用リブ、２……台部 ３……中空部、４……成形体本体 ５……キャビティ、６……溝部 ７……補助室1 (a) to 1 (d) show an injection molded article with a rib for reinforcement, FIG. 2 shows a molding example, and FIGS. 3 (a) and 3 (b) show a conventional molded article with a rib for reinforcement. . DESCRIPTION OF SYMBOLS 1 ... Reinforcing rib 2 ... Base part 3 ... Hollow part 4 ... Molded body 5 ... Cavity 6 ... Groove part 7 ... Auxiliary chamber
フロントページの続き (56)参考文献 特開 昭47−5841（ＪＰ，Ａ) 特開 昭54−111557（ＪＰ，Ａ) 特開 昭55−77522（ＪＰ，Ａ) 特開 昭56−60214（ＪＰ，Ａ) 特開 昭60−8022（ＪＰ，Ａ) 特開 昭63−268611（ＪＰ，Ａ) 特公 昭43−3996（ＪＰ，Ｂ１) 特公 昭49−2302（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.6，ＤＢ名) B29C 45/00 - 45/84 B29L 22:00Continuation of the front page (56) References JP-A-47-5842 (JP, A) JP-A-54-111557 (JP, A) JP-A-55-77522 (JP, A) JP-A-56-60214 (JP) JP-A-60-8022 (JP, A) JP-A-63-268611 (JP, A) JP-B-43-3996 (JP, B1) JP-B-49-2302 (JP, B1) (58) Field surveyed (Int.Cl. 6 , DB name) B29C 45/00-45/84 B29L 22:00
Claims (1)
強用リブより幅広で中空の台部が一体に形成されている
ことを特徴とする補強用リブ付射出成形体。1. An injection-molded article with reinforcing ribs, wherein a hollow base part wider than the reinforcing ribs is integrally formed at the intersection of the reinforcing ribs and the molded body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP153090A JP2805365B2 (en) | 1990-01-10 | 1990-01-10 | Injection molded body with rib for reinforcement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP153090A JP2805365B2 (en) | 1990-01-10 | 1990-01-10 | Injection molded body with rib for reinforcement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03207617A JPH03207617A (en) | 1991-09-10 |
| JP2805365B2 true JP2805365B2 (en) | 1998-09-30 |
Family
ID=11504076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP153090A Expired - Lifetime JP2805365B2 (en) | 1990-01-10 | 1990-01-10 | Injection molded body with rib for reinforcement |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2805365B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2574354Y2 (en) * | 1991-10-09 | 1998-06-11 | マツダ株式会社 | Projection structure of injection molded product |
| JP5764529B2 (en) * | 2012-06-25 | 2015-08-19 | 日立オートモティブシステムズ株式会社 | Pressure sensor device |
| SE1250876A1 (en) * | 2012-07-18 | 2014-01-19 | Scania Cv Ab | Panel Wholesale |
| US9987779B2 (en) | 2015-06-18 | 2018-06-05 | Ford Global Technologies, Llc | Integral locator pin for a plastic component |
-
1990
- 1990-01-10 JP JP153090A patent/JP2805365B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03207617A (en) | 1991-09-10 |
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