Injection molding mold and method for manufacturing injection molded product

Abstract

This disclosure provides an injection molding die capable of improving the sealing between the parting surfaces of a first die and a second die. One aspect of the invention is an injection molding die comprising: a first die and a second die supported for changing between a closed state and an open state; parting surfaces disposed on the first die and the second die, overlapping each other in the closed state; a cavity formed on one or both of the first die and the second die, recessed from the parting surface; a metal annular protrusion projecting from the parting surface of the first die and surrounding the entire circumference of the cavity, having a cross-sectional shape that narrows towards the apex; and an annular groove recessed in the parting surface of the second die and surrounding the entire circumference of the cavity, having an inner surface that abuts against the annular protrusion surface in the closed state.

Description

Technical Field

[0001] This disclosure relates to an injection molding die and a method for manufacturing an injection molded article using the injection molding die. Background Technology

[0002] Injection molding dies that are divided into a first mold and a second mold are known (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-236888 ( Figure 2 wait) Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] This disclosure discloses an injection molding die that can improve the sealing between the parting surfaces of the first and second molds.

[0008] Methods for solving problems

[0009] One aspect of the invention is an injection molding die comprising: a first mold and a second mold supported for changing to a closed state and a closed state; a parting surface disposed on the first mold and the second mold, overlapping each other in the closed state; a cavity formed on one or both of the first mold and the second mold, and recessed from the parting surface; a metal annular protrusion protruding from the parting surface of the first mold and surrounding the entire circumference of the cavity, and having a cross-sectional shape that narrows towards the apex; and an annular groove recessed in the parting surface of the second mold and surrounding the entire circumference of the cavity, and having an inner surface that abuts against the annular protrusion surface in the closed state. Attached Figure Description

[0010] Figure 1 This is a front sectional view of the injection molding die in the closed state according to the first embodiment.

[0011] Figure 2 This is a front sectional view of an injection mold in its open state.

[0012] Figure 3 This is a front sectional view of the annular protrusions and annular grooves that are in contact with each other in the mold-closed state.

[0013] Figure 4 It is a front sectional view of the annular protrusion and annular groove in the mold-open state.

[0014] Figure 5This is a front sectional view of the second mold before the annular groove is formed.

[0015] Figure 6 This is a front sectional view of an injection mold with an inner mold configured in the mold-closed state.

[0016] Figure 7 This is a front sectional view of an injection-molded product formed in an injection mold in the mold-closed state.

[0017] Figure 8 It is a frontal sectional view near the annular protrusion of the injection-molded part.

[0018] Figure 9 This is a front sectional view of the injection mold during the mold opening process.

[0019] Figure 10 A is a side sectional view of an injection-molded article formed in an injection mold in the mold-closed state. Figure 10 B is a side sectional view of the injection mold.

[0020] Figure 11 This is a front sectional view of the injection-molded product after demolding.

[0021] Figure 12 This is a front sectional view of the annular protrusions and annular grooves of an injection molding die in other embodiments.

[0022] Figure 13 This is a front sectional view of the annular protrusions and annular grooves of an injection molding die in other embodiments. Detailed Implementation

[0023] [First Implementation]

[0024] exist Figure 1 The image shows an injection molding die 100 according to a first embodiment. The injection molding die 100 includes a first die 10 and a second die 20. The first die 10 and the second die 20 are supported in a closed state that allows them to be fitted together (see reference). Figure 1 ) and the mold opening state that is separated from each other (refer to Figure 2 It should be noted that, in this embodiment, the first mold 10 and the second mold 20 overlap in the vertical direction (the first mold 10 is disposed on the lower side) and are close to and separate in the vertical direction.

[0025] The first mold 10 and the second mold 20 each have parting surfaces 11 and 21 that overlap each other in the mold-closed state, and cavities 12 and 22 are recessed from opposing portions of these parting surfaces 11 and 21. In the injection molding mold 100, in the molding space R formed by the cavities 12 and 22 in the mold-closed state, the injection-molded article 90 (see reference) Figure 11 It is injection molded.

[0026] In this embodiment, the injection-molded article 90 formed by the injection molding mold 100 is a pipe (e.g., the air intake pipe of an engine in a vehicle or other vehicle), but it is not limited to this. Furthermore, the material of the injection-molded article 90 is not particularly limited; for example, it can be made of rubber or resin.

[0027] like Figure 3 and Figure 4 As shown, a metal annular protrusion 30 protrudes from the parting surface 11 of the first mold 10. The annular protrusion 30 is arranged along the cavity 12, surrounding the entire circumference of the cavity 12. Figure 2 As shown, the annular protrusion 30 has a cross-sectional shape that narrows towards its protruding tip. In this embodiment, the annular protrusion 30 is disposed at a distance K from the cavity 12. The distance K is, for example, 0.1 mm to 0.3 mm.

[0028] The parting surface 21 of the second mold 20 is recessed to form an annular groove 40. The annular groove 40 surrounds the entire circumference of the cavity 22. The annular groove 40 is positioned to overlap with the annular protrusion 30 in the mold-closed state, and the inner surface of the annular groove 40 abuts against the outer surface of the annular protrusion 30 in the mold-closed state. Thus, the parting surface 11 and the parting surface 21 are sealed.

[0029] like Figure 4 As shown, in this embodiment, the protrusion H (protrusion height) of the annular protrusion 30 is greater than the depth D of the annular groove 40, and the parting surface 11 of the first mold 10 and the parting surface 21 of the second mold 20 are arranged with a gap S between them in the mold-closed state (see reference). Figure 3 By setting a gap S, foreign objects can be repelled into the gap S when they enter the parting surfaces 11 and 21. This prevents the inner surface of the annular groove 40 from lifting off the outer surface of the annular protrusion 30 due to foreign objects in the mold-closed state. The gap S is preferably, for example, 0.05 mm to 0.2 mm. The protrusion H of the annular protrusion 30 is, for example, 0.1 mm to 0.3 mm.

[0030] like Figure 2As shown, in this embodiment, the annular protrusion 30 has a triangular cross-sectional shape. The annular protrusion 30 has a first inclined surface 31 and a second inclined surface 32 as outer surfaces that abut against the inner surface of the annular groove 40. The first inclined surface 31 faces the inner side of the annular protrusion 30 (i.e., towards the cavity 12 side) and is continuous with the parting surface 11. The first inclined surface 31 is inclined at a certain angle α relative to the parting surface 11 in such a way that the protrusion of the annular protrusion 30 gradually increases. The second inclined surface 32 faces the outer side of the annular protrusion 30 (i.e., towards the side opposite to the cavity 12) and is continuous with the parting surface 11. The second inclined surface 32 is inclined at a certain angle β relative to the parting surface 11 in such a way that the protrusion of the annular protrusion 30 gradually increases.

[0031] The slope α of the first inclined surface 31 (the slope relative to the parting surface 11) is preferably greater than or equal to the slope β of the second inclined surface 32, and more preferably greater than twice the slope β. In the example of this embodiment, the slope α is greater than the slope β, but the slope α and the slope β can also be the same (that is, the cross-sectional shape of the annular protrusion 30 can also be an equilateral triangle).

[0032] The draft angle α is preferably 45° to 70°. This allows the draft angle α to be relatively steep, preventing the raw material from passing over the annular protrusion 30 due to the injection pressure of the injection molding material. The draft angle β is preferably 20° to 60°. This allows the draft angle β to be relatively gentle, preventing the annular protrusion 30 from being flattened when the injection mold 100 is closed. Furthermore, the apex angle θ of the annular protrusion 30 (the angle formed by the first inclined surface 31 and the second inclined surface 32) is preferably 60° to 90°. With this apex angle θ, the strength to prevent the annular protrusion 30 from being flattened when the injection mold 100 is closed can be ensured, and the strength required for the stamping process described later for forming the annular groove 40 can also be ensured.

[0033] like Figure 3 and Figure 4 As shown, in this embodiment, the annular groove 40 has a shape corresponding to the annular protrusion 30, and is triangular in shape. The inner surface of the annular groove 40 has a first inclined surface 41 and a second inclined surface 42 that abut against the first inclined surface 31 and the second inclined surface 32 of the annular protrusion 30 respectively in the mold-closed state. The slopes of the first inclined surface 41 and the second inclined surface 42 are the same as the slopes α and β of the annular protrusion 30, respectively.

[0034] In this embodiment, the first metal portion 10K in the first mold 10, which has an annular protrusion 30, has a higher hardness than the second metal portion 20K in the second mold 20, which has an annular groove 40. For example, the first metal portion 10K may be made of carbon steel (e.g., S55C), and the second metal portion 20K may be made of stainless steel (e.g., SUS420). Alternatively, the first metal portion 10K may be made of carbon steel (e.g., S55C), and the second metal portion 20K may be made of carbon steel with a lower hardness than the first metal portion 10K (e.g., S45C). In this embodiment, the annular protrusion 30 is integrally formed in the first mold 10, and the annular groove 40 is integrally formed in the second mold 20. The Brinell hardness or Rockwell hardness of the first mold 10 as a whole is higher than that of the second mold 20 as a whole.

[0035] In this embodiment, the annular groove 40 is an indentation formed by the annular protrusion 30 pressing against the parting surface 21 of the second mold 20. For example... Figure 5 As shown, the parting surface 21 of the second mold 20 was originally a flat surface without the annular groove 40. The annular groove 40 is formed by the injection molding mold 100 as shown in the diagram. Figure 1 The annular protrusion 30 is formed by pressing it against the second mold 20 using a stamping process, as shown. By forming the annular groove 40 through stamping, the inner surface shape of the annular groove 40 can be made to match the outer surface shape of the annular protrusion 30, allowing the inner surface of the annular groove 40 to abut against the outer surface of the annular protrusion 30. Furthermore, in this embodiment, the first metal portion 10K has a higher hardness than the second metal portion 20K, thus facilitating the formation of the annular groove 40 based on the aforementioned stamping. It should be noted that the annular groove 40 may not be formed by an indentation from the pressing of the annular protrusion 30; for example, it may be formed by cutting. In such cases, for example, the first metal portion 10K may have the same hardness or a lower hardness than the second metal portion 20K.

[0036] In this embodiment, as described above, the annular protrusion 30 is provided at a distance K (e.g., 0.1 mm to 0.2 mm) from the cavity 12, thus suppressing the burrs of the second mold 20 from protruding toward the forming space R when the annular protrusion 30 flattens the annular groove 40 during the stamping process.

[0037] In this embodiment, the injection molded article 90 is manufactured using the injection mold 100, for example, as follows. First, as... Figure 6As shown, the first mold 10 and the second mold 20 are set to the closed state. For example, an annular groove 40 is pre-formed in the second mold 20 by the above-described stamping process. In the closed state, the outer surface of the annular protrusion 30 abuts against the inner surface of the annular groove 40, and the parting surface 11 and the parting surface 21 are sealed. It should be noted that, in the example of this embodiment, the injection molded article 90 is a tube, therefore the inner mold 80 that forms its inner surface is disposed within the molding space R. For example, the inner mold 80 is as follows: Figure 10 The end of the support member 81 (e.g., a member configured to penetrate the first mold 10) is supported by a support member 81 located inside the annular protrusion 30 as shown in Figure A.

[0038] like Figure 7 and Figure 10 As shown in Figure A, the raw material is injected into the molding space R for injection molding, resulting in an injection molded part 90. At this time, under the action of injection pressure, the raw material flows from the molding space R into the gap S between the parting surfaces 11 and 21. However, because the annular protrusion 30 abuts against the annular groove 40, the gap between the parting surfaces 11 and 21 is sealed, thus the raw material is blocked by the annular protrusion 30 (see Figure A). Figure 8 It should be noted that the raw material flowing from the molding space R into the parting surfaces 11 and 21 and reaching the annular protrusion 30 solidifies, forming the inner flash (Japanese: バリ) B.

[0039] Next, the injection molding mold 100 is opened (refer to...). Figure 9 and Figure 10 B), obtained Figure 11 The injection-molded article 90 is shown. The injection-molded article 90 is lifted from the first mold 10 by the support member 81 and extracted from the end of the inner mold 80 that is not supported by the support member 81. It should be noted that the inner flash B can also be removed after mold opening as needed. Additionally, for example, if the injection-molded article 90 is cylindrical, such as a tube, both ends can be appropriately cut off.

[0040] In this embodiment, when the injection molding mold 100 is in the closed state, the annular protrusion 30 of the first mold 10 abuts against the annular groove 40 of the second mold 20, thus sealing the parting surfaces 11 and 21 of the first mold 10 and the second mold 20. This prevents the formation of flash due to raw material flowing into the parting surfaces 11 and 21 on the outer side of the annular protrusion 30 and the annular groove 40 (i.e., the side opposite to the cavity 12) during injection molding.

[0041] In this structure, where the second mold 20 has a flat parting surface 21 instead of an annular groove 40, the first mold 10 and the second mold 20 can be sealed together when the annular protrusion 30 of the first mold 10 abuts against the second mold 20 in the closed state. However, in this case, there is a problem: when there is a weak abutment in the sealed part, the raw material can easily flow out from there, and the flash becomes larger.

[0042] In contrast, in the injection molding mold 100 of this embodiment, an annular groove 40 is formed in the second mold 20, and the outer surface of the annular protrusion 30 abuts against the inner surface of the annular groove 40, sealing the parting surfaces 11 and 21. This strengthens the seal between the parting surfaces 11 and 21, and compared to the aforementioned line-sealed structure, it suppresses the generation of flash on the outer sides of the annular protrusion 30 and the annular groove 40. Furthermore, since the first inclined surface 31 of the annular protrusion 30 facing the cavity 12 is more upright than the second inclined surface 32 facing the opposite side (for example, since the slope α is 45°~70°), it can easily block raw material flowing in from the molding space R. Additionally, since the annular protrusion 30 is embedded in the annular groove 40, lateral displacement of the second mold 20 relative to the first mold 10 can be suppressed.

[0043] [Other Implementation Methods]

[0044] In the above embodiment, the annular protrusion 30 has a triangular cross-sectional shape, and the annular groove 40 has a triangular groove shape. However, the annular protrusion 30 is not limited to this as long as it has a cross-sectional shape that narrows towards the apex. For example, it could also be as follows: Figure 12 As shown, the annular protrusion 30 has a dome-shaped cross-section, and the annular groove 40 has a circular groove shape. The outer surface of the annular protrusion 30 and the inner surface of the annular groove 40 abut against each other with curved surfaces. Alternatively, the annular protrusion 30 may also have a trapezoidal cross-section shape with a first inclined surface 31 and a second inclined surface 32. In this case, the annular groove 40 may also have a trapezoidal cross-section shape that abuts against the surface of the annular protrusion 30.

[0045] In the above embodiment, the annular protrusion 30 is integrally formed on the first mold 10, but it can also be a first metal part 10K including the annular protrusion 30 mounted on the parting surface 11 of the first mold 10 (see reference). Figure 13 In this case, the portion of the first mold 10 other than the first metal portion 10K may have the same hardness as the second metal portion 20K of the second mold 20, or a lower hardness compared to the second metal portion 20K of the second mold 20. Alternatively, the second metal portion 20K, including the annular groove 40, may be mounted on the parting surface 21 of the second mold 20. In this case, the portion of the second mold 20 other than the second metal portion 20K may have the same hardness as the first metal portion 10K of the first mold 10, or a higher hardness compared to the first metal portion 10K of the first mold 10.

[0046] In the above embodiments, the first mold 10 and the second mold 20 may also be made of metals with the same hardness, and the hardness of the first metal part 10K may be increased by quenching the first metal part 10K.

[0047] In the above embodiments, the cavity can be formed in both the first mold 10 and the second mold 20, or it can be formed in only one of them.

[0048] In the above embodiment, the first mold 10 with annular protrusions 30 is disposed on the lower side, and the second mold 20 with annular grooves 40 is disposed on the upper side, but it can also be an inverted structure. In the above embodiment, the mold opening direction of the first mold 10 and the second mold 20 is the vertical direction, but the mold opening direction can also be the horizontal direction.

[0049] In the above embodiment, the cylindrical molding space R of the cylindrical resin molded article 90, such as the molding tube, is arranged in a horizontal direction, but it can also be arranged in a vertical direction (the opposing direction of the first mold 10 and the second mold 20). In this case, for example, the annular protrusion 30 and the annular groove 40 are provided along the outer periphery of the cylindrical cavity. Furthermore, the annular protrusion 30 and the annular groove 40 can also be provided along the inner periphery of the cylindrical cavity.

[0050] In the above embodiments, the first mold 10 and the second mold 20 are provided with annular protrusions 30 and annular grooves 40 surrounding the entire circumference of the cavities 12 and 22. However, it is also possible to provide metal protrusions and grooves that abut against each other in the mold-closed state along a portion of the circumference of the cavities 12 and 22. In this case, for example, a resin sealing member that seals the parting surfaces 11 and 21 can also be provided in the remaining portion of the circumference of the cavities 12 and 22.

[0051] <Postscript>

[0052] Hereinafter, effects and explanations will be provided for the feature groups extracted from the above embodiments, as needed.

[0053] For example, the following feature group of this disclosure relates to "injection molding die and method for manufacturing injection molded article using the injection molding die", which can be considered to be directed to "injection molding die known to be divided into a first mold and a second mold (for example, see Japanese Patent Application Publication No. 2003-236888)". Figure 2 The background technology, such as “etc.”, is used to conceive of a feature group with the subject matter of “disclosing an injection molding die that can improve the sealing between the parting surfaces of the first and second dies”. In addition, there has been a continuous pursuit of new injection molding dies, new injection molded products, and new manufacturing methods for injection molded products.

[0054] [Feature 1]

[0055] An injection molding die, wherein,

[0056] The injection molding die has the following features:

[0057] The first mold and the second mold are supported so as to be able to change to a closed state and a closed state;

[0058] The parting surfaces are disposed on the first mold and the second mold, and overlap each other in the mold-closed state;

[0059] A cavity is formed in one or both of the first mold and the second mold, and is recessed from the parting surface;

[0060] A metal annular protrusion, projecting from the parting surface of the first mold and surrounding the entire circumference of the cavity, having a cross-sectional shape that narrows towards the apex; and

[0061] An annular groove is recessed into the parting surface of the second mold and surrounds the entire circumference of the cavity, and has an inner surface that abuts against the annular protrusion in the mold-closed state.

[0062] [Feature 2]

[0063] According to feature 1, the injection molding die, wherein,

[0064] The first metal part with the annular protrusion in the first mold has a higher hardness than the second metal part with the annular groove in the second mold.

[0065] [Feature 3]

[0066] According to feature 1 or 2, the injection molding die, wherein,

[0067] The height of the annular protrusion is greater than the depth of the annular groove.

[0068] [Feature 4]

[0069] The injection molding die according to any one of features 1 to 3, wherein,

[0070] The annular protrusion has a first inclined surface that is continuous with the parting surface toward the inner side of the annular protrusion and a second inclined surface that is continuous with the parting surface toward the outer side of the annular protrusion, serving as an outer surface that abuts against the inner surface of the annular groove.

[0071] The slope of the first inclined plane is greater than or equal to the slope of the second inclined plane.

[0072] [Feature 5]

[0073] According to feature 4, the injection molding die, wherein,

[0074] The slope of the first inclined plane is twice as large as the slope of the second inclined plane.

[0075] [Feature 6]

[0076] The injection molding die according to any one of features 1 to 3, wherein,

[0077] The annular protrusion has a dome-shaped cross-section.

[0078] The annular groove is circular.

[0079] The outer surface of the annular protrusion abuts against the inner surface of the annular groove with a curved surface.

[0080] [Feature 7]

[0081] The injection molding die according to any one of features 1 to 6, wherein,

[0082] The annular groove is an indentation formed by the annular protrusion pressing against the parting surface of the second mold.

[0083] [Feature 8]

[0084] A method for manufacturing an injection-molded article, wherein,

[0085] Injection molded articles are manufactured using any one of features 1 to 5.

[0086] Based on the above features, the sealing performance between the parting surfaces of the first mold and the second mold can be improved.

[0087] It should be noted that specific examples of the technology included in the patented technical solution are disclosed in this specification and drawings, but the technology described in the patented technical solution is not limited to these specific examples. It also includes solutions obtained by various modifications and alterations to the specific examples, as well as solutions obtained by taking a part of the specific examples out separately.

[0088] Explanation of reference numerals in the attached figures

[0089] 10 First mold

[0090] 10K First Metal Division

[0091] 11 Parting Surface

[0092] Type 12 cavity

[0093] 20 Second mold

[0094] 20K Second Metal Section

[0095] 21 parting surface

[0096] 22-type cavity

[0097] 30 ring-shaped protrusions

[0098] 31 First inclined plane

[0099] 32 second slope

[0100] 40 Annular groove

[0101] 41 First inclined plane

[0102] 42 Second slope

[0103] 80 internal mold

[0104] 90 Injection Molded Products

[0105] 100 Injection Molding Mold

[0106] B Inner Flanged Edge

[0107] D Depth

[0108] H protrusion amount

[0109] K interval

[0110] R molding space

[0111] S gap

[0112] α slope

[0113] β slope

[0114] θ is the vertex angle.

Claims

1. An injection molding die, wherein, The injection molding die has the following features: The first mold and the second mold are supported so as to be able to change to a closed state and a closed state; The parting surfaces are disposed on the first mold and the second mold, and overlap each other in the mold-closed state; A cavity is formed in one or both of the first mold and the second mold, and is recessed from the parting surface; A metal annular protrusion protrudes from the parting surface of the first mold and surrounds the entire circumference of the cavity, and has a cross-sectional shape that narrows towards the top. as well as An annular groove is recessed into the parting surface of the second mold and surrounds the entire circumference of the cavity, and has an inner surface that abuts against the annular protrusion in the mold-closed state.

2. The injection molding die according to claim 1, wherein, The first metal part with the annular protrusion in the first mold has a higher hardness than the second metal part with the annular groove in the second mold.

3. The injection molding die according to claim 1 or 2, wherein, The height of the annular protrusion is greater than the depth of the annular groove.

4. The injection mold according to any one of claims 1 to 3, wherein, The annular protrusion has a first inclined surface that is continuous with the parting surface toward the inner side of the annular protrusion and a second inclined surface that is continuous with the parting surface toward the outer side of the annular protrusion, serving as an outer surface that abuts against the inner surface of the annular groove. The slope of the first inclined plane is greater than or equal to the slope of the second inclined plane.

5. The injection mold according to any one of claims 1 to 3, wherein, The annular protrusion has a dome-shaped cross-section. The annular groove is circular. The outer surface of the annular protrusion abuts against the inner surface of the annular groove with a curved surface.

6. A method for manufacturing an injection-molded article, wherein, Injection molded articles are manufactured using the injection molding mold as described in any one of claims 1 to 5.

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