JP4881680B2 - Injection mold and molded product with synthetic resin cage - Google Patents

Description

  The present invention relates to an injection mold for molding a molded product with a hook such as a test tube and a writing instrument and a molded product with a synthetic resin hook.

  An injection mold for molding a cylindrical molded product such as a test tube or a writing instrument is provided with a plurality of cavities in one molding mold, and the molten resin injected from a resin injection port is distributed by a hot runner. It is configured to lead to the cavity.

  This injection mold is configured so that a plurality of molded products can be simultaneously molded by one injection molding, basically, one resin injection port in the sprue portion provided in the center portion, A branch gate that branches into a plurality of branches is provided. On the other hand, the mold body is provided with a plurality of cavities, and a hot runner having an edge gate communicating with the cavities is provided. Then, the resin pressure from the resin passage of the hot runner is uniformly distributed to the edge gate that opens to the cavity forming cavity portion of the cavity via the branch gate (see, for example, Patent Document 1).

In addition, as an injection mold, it has a barrel molding cavity and a flange molding cavity at the opening end of the barrel molding cavity, a cavity for molding a molded product with a flange, and molding a hip from a hot runner An injection mold of a syringe syringe provided with an edge gate leading to the side of the cavity is known (for example, see Patent Document 2).
Japanese Patent Laid-Open No. 2005-41020 Japanese Patent No. 3396880

However, the injection mold of Patent Document 1 has a problem that a gate mark remains in the body portion of the molded product because the edge gate is opened in the body portion forming cavity portion of the cavity. In addition, since the injection gate of Patent Document 2 has an edge gate opened to the cavity forming cavity portion of the cavity, the gate mark does not remain in the body portion of the molded product, thus eliminating the problem of Patent Document 1. it can.
However, when the resin filled in the flange molding cavity is cooled, a contraction is formed between the opening hole of the edge gate, and the molten resin flows out of the edge gate into this gap, so that the molded product can be removed. There is a problem that the resin residue is generated in the part and the quality of the molded product is deteriorated.
The present invention has been made paying attention to the above circumstances, and the purpose thereof is to leave a gate mark on the flange of the molded product even if an edge gate communicating with the cavity for molding the flange of the cavity is provided. An object of the present invention is to provide an injection mold capable of improving the quality of a molded product and a molded product with a synthetic resin ridge.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a fixed mold, a movable mold capable of contacting and separating from the fixed mold, and the fixed mold and the movable mold. A body molding cavity part and a flange part molding cavity part at the opening end of the body part molding cavity part, and communicate with a cavity for molding a molded product with a collar and a resin injection port provided in the fixed mold. A hot runner having a resin passage and an edge gate provided in the hot runner for filling the cavity with molten resin, and a body portion on the flange portion of the flange-molded product. A rib forming cavity for forming a rib protruding in the axial direction of the rib is provided, a shearing wall is formed in the thickness direction of the flange portion, and an opening hole of the edge gate is provided facing the shearing wall. Injection In the metal mold.

  According to a second aspect of the present invention, the opening hole of the edge gate of the first aspect is characterized in that the resin is cut by rubbing the opening hole with a shearing wall at the time of die-cutting of the flanged molded product.

  According to the present invention, the rib forming cavity portion for forming the rib protruding in the axial direction of the trunk portion is provided in a part of the flange portion of the flanged molded product in the flange forming cavity portion so that the rib portion in the thickness direction of the flange portion is provided. By forming a shearing wall and providing an opening hole in the edge gate so as to face this shearing wall, when the molded product with a flange is punched, the resin is cut by rubbing the shearing wall and the molded product with the flange is There is no gate mark on the buttock, and the quality of the molded product can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a vertical side view of an injection mold, FIG. 2 is an enlarged vertical side view of a portion X in FIG. 1, and FIG. 3 is a perspective view of a molded product with a synthetic resin ridge. The injection mold 11 is a mold for molding a flanged molded product A. As shown in FIG. 1, a plurality of molded products A are molded simultaneously on one injection mold 11. A molding part 12 is provided.

  The injection mold 11 will be described. The injection mold 11 includes a fixed mold 13 and a movable mold 14 and is divided by a dividing surface 15. The fixed mold 13 is provided with a hot runner 16 communicating with a resin injection port (not shown), and the molten resin injected from the resin injection port is branched and guided to a plurality of molding parts 12.

  A resin passage 17 is provided in the axial center portion of the hot runner 16, and a heater 18 is wound around the outer periphery of the resin passage 17. An edge gate 19 is provided at the lower end of the hot runner 16, that is, at the downstream side of the resin passage 17. The edge gate 19 is made of, for example, a heat conductive alloy such as Be-Cu, and has a cylindrical portion 19b having a resin passage 19a communicating with the resin passage 17, and a widening portion 19c having a widening end provided integrally with the cylindrical portion 19b. have. The widened portion 19c is provided with a plurality of branch gates 20a and 20b corresponding to the number of the molded portions 12, which are bifurcated left and right in the present embodiment. On the downstream side of these branch gates 20a and 20b, opening holes 21a and 21b that are opened on the left and right side surfaces of the edge gate 19 are provided. A resin heat insulating layer 19 c is provided around the edge gate 19.

  The cylindrical portion 19b of the edge gate 19 thus configured is inserted into a mounting hole 22 drilled along the axis at the lower end portion of the hot runner 16, and the upper end surface of the cylindrical portion 19b is the bottom surface 22a of the mounting hole 22. Abut. A mounting hole 23 is formed in the lower end portion on the axis of the edge gate 19, and a receiving piece 24 made of a material having heat resistance such as ceramic and having a small thermal expansion coefficient is fixed to the mounting hole 23. ing. The receiving piece 24 is in contact with a gate pad 25 provided on the movable mold 14. And even if the resin pressure is applied to the edge gate 19, the edge gate 19 is prevented from lowering in the drawing.

  Next, the molding part 12 will be described. The cavity 26 for molding the flanged molded product A is composed of a trunk part molding cavity part 27 and a collar part molding cavity part 28. The body molding cavity 27 and the collar molding cavity 28 are a cavity outer cylinder 29 provided in the fixed mold 13 and a cavity provided in the movable mold 14 and inserted into the cavity outer cylinder 29. It is comprised by the clearance gap between the inner cylinder parts 30. FIG.

Further, as shown in FIG. 2, a rib A3 protruding in the axial direction of the body part A2 is formed on a part of the collar part A1 of the molded product A with a collar on a part of the outer peripheral part of the collar molding cavity part 28. A rib forming cavity portion 28a is provided. Then, a high shearing wall A4 is formed in the thickness direction of the flange portion A1 of the flanged molded product A, and the opening hole 21a (21b) of the edge gate 19 is opposed to the shearing wall A4. The molten resin injected from the opening hole 21a (21b) is filled into the flange forming cavity 28 from a location corresponding to the shearing wall A4.
Furthermore, a pipe 32 is concentrically provided in the axial direction in the inner cavity 30a of the inner cylinder portion 30 with a gap 31 on the outer peripheral surface. The inside of the pipe 32 is provided with a cooling water forward path 33, and the gap portion 31 is provided with a cooling water backward path 34 that communicates with the cooling water forward path 33 at the tip of the pipe 32. The cooling water forward path 33 communicates with a discharge side of a cooling water supply source (not shown), and the cooling water return path 34 constitutes a cooling water circulation path communicating with a suction side of the cooling water supply source. And the molten resin with which the cavity 26 was filled is cooled uniformly from the inside.

  A spiral cooling water channel (not shown) is provided over the entire length of the outer peripheral portion of the cavity outer cylinder portion 29 to uniformly cool the molten resin filled in the cavity 26 from the outside.

  Further, a hemispherical portion 35 is provided at the distal end portion of the body portion forming cavity portion 27. A block 36 that is fixed to the fixed mold 13 is provided on the distal end side of the body portion forming cavity portion 27. The block 36 is provided with a recessed portion 37 that forms a hemispherical portion 35.

  Next, the operation of the injection mold configured as described above will be described.

  When molten resin is injected from a resin injection port (not shown) into the injection mold 11 from the injection molding machine, the molten resin is guided to the resin passage 17 of the hot runner 16. The molten resin in the resin passage 17 is led from the hot runner 16 to the branch gates 20a and 20b through the resin passage 19a of the edge gate 19, and the resin heat insulating layer 19b provided around the edge gate 19 and the opening holes 21a, The cavity 26 is filled through 21b. That is, when the molten resin is filled into the cavity 26 from the branch gates 20a and 20b through the opening holes 21a and 21b, a part of the semi-molten resin in the resin heat insulating layer 19c is combined with the injected molten resin. The cavity 26 is filled with the molten resin, and the molten resin is filled in the order of the collar part molding cavity part 28 to the body part molding cavity part 27 and the hemispherical part 35.

  At this time, the edge gate 19 is pressed downward by the pressure of the molten resin, but the receiving piece 24 fixed to the edge gate 19 is in contact with the receiving base 25 provided in the movable mold 14. 19 can be prevented from falling.

  Further, since the cooling water passage is provided so as to surround the outside of the cavity 26, the molten resin filled in the cavity 26 is uniformly cooled from the outside. Inside the cavity 26, a cooling water circulation path is formed in which the cooling water flowing from the cooling water supply source flows through the cooling water forward path 33, is folded at the tip of the pipe 32, and flows to the cooling water return path 34. The molten resin filled in the inside is uniformly cooled also from the inside.

  Therefore, the resin in the cavity 26 is cooled and solidified in a short time. After the resin is cooled and solidified, when the movable mold 14 is retracted with respect to the fixed mold 13, the fixed mold 13 and the movable mold 14 are divided by the dividing surface 15, and the hooked molding following the shape of the cavity 26 is formed. Product A is obtained.

At this time, a rib forming cavity portion 28a for forming a rib A3 protruding in the axial direction of the body portion A2 is provided on a part of the flange portion A1 of the flanged molded product A on the outer peripheral portion of the flange portion forming cavity portion 28, A high shearing wall A4 is formed in the thickness direction of the flange portion A1 of the molded product A with the flange. Therefore, the shearing wall A4 of the flange portion A1 of the flanged molded product A is rubbed with the opening holes 21a and 21b during die cutting to cut the resin. Therefore, as shown in FIG. 3, the gate mark does not remain in the flange portion A1 of the flanged molded product A, and the quality of the synthetic resin flanged molded product can be improved. That is, the opening holes 21a and 21b slide and rub against the shearing wall A4 of the flanged molded product A during die cutting. Since the resin is cut at the portion of the wall A4, the resin of the flange portion A1 of the flanged molded product A does not remain, and a high-quality molded product can be obtained.
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal side view of an injection mold showing a first embodiment of the present invention. The vertical side view which expanded the X section of FIG. 1 which showed the same embodiment. The perspective view of the molded product with a hook which shows the same embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Injection mold, 13 ... Fixed mold, 14 ... Movable mold, 15 ... Dividing surface, 16 ... Hot runner, 17 ... Resin passage, 19 ... Edge gate, 21a, 21b ... Opening hole, 26 ... Cavity, 27 ... barrel forming cavity, 28 ... collar molding cavity, 28a ... rib molding cavity, A ... molded product with flange, A1 ... collar, A2 ... trunk, A3 ... rib, A4 ... shearing wall

Claims (2)

A fixed mold, a movable mold that can be brought into and out of contact with the fixed mold, a body molding cavity provided between the fixed mold and the movable mold, and an opening end of the body molding cavity. A cavity for forming a molded product with a flange having a flange molding cavity, a hot runner having a resin passage communicating with a resin inlet provided in the fixed mold, and a molten resin provided in the hot runner An edge gate filling the cavity,
A rib forming cavity part for forming a rib projecting in the axial direction of the body part is provided in a part of the collar part of the flanged molded product in the collar part molding cavity part, and a shearing wall is provided in the thickness direction of the collar part. An injection mold having an opening hole for the edge gate formed and opposed to the shearing wall.   2. The injection mold according to claim 1, wherein the opening hole of the edge gate is cut by resin by rubbing the opening hole with a shearing wall at the time of die-cutting of the molded product with a flange.

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