JP2019123139A - Injection mold - Google Patents

Abstract

To provide an injection mold whose inclined core is hard to break and capable of increasing design freedom of a molded article.SOLUTION: An injection mold 10 molds a resin molded product having a body having a first main surface and an undercut structure formed on the first main surface. The injection mold 10 includes: a first mold 1 for molding at least an outer surface of the undercut structure; a movable core 3 for molding at least an inner surface of the undercut structure; and a second mold 2 for molding a second main surface of the body. The movable core 3 has a movable piece 31 having a projecting portion 34 for forming the inner surface of the undercut structure, and a core main portion 32 which is separate from the movable piece 31. The movable piece 31 is attached to the core main portion 32 so that a posture change in a direction in which a tip end of the projecting portion 34 approaches and separates from the first mold 1 is possible.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mold for injection molding.

  In order to mold a resin molded product having an undercut shape, for example, a mold provided with a sloped core is used (see, for example, Patent Document 1). The undercut is formed by the projection of the inclined core. If there is a gap between the sloped core and the mold body when the sloped core is at the retraction limit, the sloped core may be retracted under resin pressure during molding. Depending on the shape of the undercut portion, the thickness of the protruding portion of the inclined core becomes thin, and therefore the protruding portion is deformed by the pressure of the resin, and fatigue failure easily occurs.

  Generally, molds used for injection molding are expensive, so injection molding is often applied to resin molded products with a large production volume, and the frequency of use of the molds is high. Also, if the sloped core is broken, fragments may fall off and be sandwiched between the sloped core and the mold body to damage the mold. Therefore, since fatigue failure of the inclined core is a problem that interferes with the production of a molded product, a design having a high safety factor is required to prevent breakage of the inclined core. Considering the safety factor, it is required to form the protruding portion of the inclined core thick, which may limit the degree of freedom in the design of the molded product. For example, when manufacturing a resin molded product having a clip seat having an undercut shape, a design with a low height of the clip seat has been difficult to adopt.

Japanese Patent Application Laid-Open No. 10-264217

  An object of one aspect of the present invention is to provide an injection mold that is resistant to breakage of the inclined core and can increase design freedom of a molded article.

  One embodiment of the present invention is an injection molding die for molding a resin molded product having a main body having a first main surface and an undercut structure formed on the first main surface, the mold being at least A first mold for molding the outer surface of the undercut structure, a moving core for molding the inner surface of the undercut structure, and a second main surface opposite to the first main surface of the main body The movable core has a movable piece having a projecting portion for forming the inner surface of the undercut structure, and a core main portion which is separate from the movable piece. The movable piece is mounted on the main part of the core so as to be able to change its posture in the direction in which the tip end of the protrusion approaches and separates from the first mold; provide.

  A first forming surface for forming a first partial region of the first main surface, the movable piece being continuous with the inner surface of the undercut structure, the protruding portion projecting in a first direction with respect to the core main portion; The main core portion has a main opposing surface facing the main outer surface opposite to the first molding surface of the movable piece, and the main opposing surface has the tip of the protrusion Preferably, a part of the movable piece in a posture closest to the first mold is chamfered to be receivable.

  The movable piece is attached to the core main portion by a connecting portion connecting the main outer surface and the main opposing surface, and the position of the connecting portion in the first direction is a range of the main outer surface in the first direction. It is preferable that it is the same as the center of, or closer to the first direction than the center.

  It is preferable that the connecting portion be formed by a fixing tool inserted from the core main portion to the movable piece.

  It is preferable that the movable piece further includes a movable piece base, the main outer surface is formed on the movable piece base, and the protrusion protrudes in the first direction with respect to the movable piece base.

According to one aspect of the present invention, since the movable piece can change its posture, bending stress applied to the protrusion by the pressure of the resin can be alleviated by the change in posture of the movable piece, and breakage of the protrusion can be prevented. Since the protrusion is not easily damaged, the protrusion can be formed thin. Therefore, since there are few restrictions in the height dimension of an undercut structure part etc., the freedom of design of a resin molded product is high. Therefore, according to one aspect of the present invention, the moving core is less likely to be broken, and the design freedom of the resin molded product can be enhanced.
Further, according to one aspect of the present invention, since the movable piece is separate from the core main portion, replacement of the movable piece is easy. Therefore, it is also excellent in terms of maintainability.

It is a sectional view of a mold for injection molding concerning an embodiment. It is sectional drawing of the inclination core of the injection mold of FIG. It is explanatory drawing which shows the shaping | molding method using the metal mold | die for injection molding of FIG. It is explanatory drawing which shows the shaping | molding method using the metal mold | die for injection molding of FIG. It is explanatory drawing which shows the shaping | molding method using the metal mold | die for injection molding of FIG. It is the schematic of the resin molded product formed of the injection mold of FIG. It is explanatory drawing which shows the shaping | molding method using the metal mold | die for injection molding which concerns on a comparison form. It is sectional drawing of the modification of an inclination core.

  Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings. The drawings used in the following description are for describing the configuration of the embodiment of the present invention, and the sizes, thicknesses, dimensions, and the like of the illustrated parts may differ from the actual device dimensional relationships. is there.

Prior to the description of the injection molding die of the embodiment, an example of a resin molded product produced by the injection molding die will be described.
FIG. 6 is a schematic view of a resin molded product 20 which is an example of a resin molded product manufactured by the injection mold of the embodiment.
As shown in FIG. 6, the resin molded product 20 includes a plate-shaped main body 21 and a clip seat 22 (undercut structure) provided on the first major surface 21 a of the main body 21.

  The clip seat 22 is formed in a bent plate shape having a base 23 and an extension 24. The base portion 23 is formed in a plate shape projecting perpendicularly to the first major surface 21 a. The extension portion 24 is formed in a plate shape extending obliquely with respect to the base 23 from the tip (protruding end) of the base 23. The extension part 24 is parallel to the main body part 21, for example. Reference numeral 22 b denotes the outer surface of the clip seat 22 (the outer surface 23 b of the base 23 and the outer surface 24 b of the extending portion 24).

The inner surface 22a of the clip seat 22 (the inner surface 23a of the base 23 and the inner surface 24a of the extension 24) has an undercut shape, so the clip seat 22 is an undercut structure.
The "undercut structure portion" moves the first mold and the second mold away from each other when molding a resin molded product using the first mold and the second mold with the inner surfaces facing each other. It has a structure that prevents the first mold or the second mold from moving in the relevant direction when it is attempted. When the clip seat 22 of the resin molded product 20 tries to move the first mold 1 and the second mold 2 (see FIG. 3) in the direction separating from each other, the extension 24 (see FIG. 3) is inclined It has a structure that prevents the movement of the protrusion 34 (see FIG. 3) of the core 3. Therefore, the clip seat 22 is an undercut structure.
The surface of the main body 21 opposite to the first main surface 21 a is referred to as a second main surface 21 b.

[Embodiment]
Next, a mold for injection molding according to the embodiment will be described.
FIG. 1 is a cross-sectional view of an injection mold 10 according to the embodiment. FIG. 2 is a cross-sectional view of the inclined core 3.
As shown in FIG. 1 and FIG. 2, the injection mold 10 includes a first mold 1, a second mold 2, and an inclined core 3 (moving core). In the following description, the positional relationship of each member will be described with reference to FIG. The second mold 2 is located above the first mold 1. The front is the left side (the direction of arrow F) in FIG. 1, and the rear is the right side (the direction of arrow R) in FIG.

  An air gap 4 is secured between the first mold 1, the second mold 2 and the inclined core 3. The void 4 has a shape corresponding to the resin molded product 20 (see FIG. 6) to be molded. The inner surface 1 a of the first mold 1 and the inner surface 2 a of the second mold 2 face each other through the gap 4.

The inner surface 1a of the first mold 1 has a main molding surface 1b for molding a part of the first main surface 21a (see FIG. 6) of the main body portion 21 of the resin molded product 20.
In FIG. 1, the X direction is the length direction of the main molding surface 1b (left and right direction in FIG. 1). The Y direction is a direction perpendicular to the X direction in the plane along the main molding surface 1b, and is a direction perpendicular to the paper surface. The Z direction is a direction orthogonal to the X direction and the Y direction, and is the thickness direction of the air gap 4 (that is, the opposing direction of the first mold 1 and the second mold 2). The Z direction is the vertical direction.

The inner surface 1a of the first mold 1 has an outer surface forming recess 11 forming the outer surface 22b (see FIG. 6) of the clip seat 22 and a receiving recess 12 for receiving the main body portion 36 of the core main portion 32 of the inclined core 3 Is formed.
The inner surface of the outer surface forming recess 11 is a side surface 11a (front surface) which is a molding surface forming the outer surface 23b (see FIG. 6) of the base 23 and a molding surface forming the outer surface 24b (see FIG. 6) And a bottom surface 11b.

The housing recess 12 is formed at the rear of the outer surface forming recess 11. The inner surface of the housing recess 12 includes a bottom surface 12a facing the bottom surface 36d of the main body portion 36, a front side surface 12b facing the front side surface 36b of the main body portion 36, and a rear side surface 12c facing the rear side surface 36c of the main body portion 36. Have.
The bottom surface 12 a of the housing recess 12 is formed with an insertion hole 13 through which the extension portion 37 is inserted.

As shown in FIG. 2, the inclined core 3 includes a movable piece 31, a core main portion 32, and a fixture 50.
The movable piece 31 is separate from the core main portion 32. The movable piece 31 includes a movable piece base 33 and a protrusion 34.
The movable piece base 33 is formed in a rectangular shape. The main outer surface 33 b which is the bottom surface of the movable piece base 33 is, for example, parallel to the upper surface 31 a of the movable piece 31 (the upper surface 33 a of the movable piece base 33 and the upper surface 34 a of the projecting portion 34). The main outer surface 33 b is formed with an insertion hole 35 into which the shaft 52 of the fixing tool 50 is inserted.
33 c is a front side surface of the movable piece base 33. 33 d is a rear side surface of the movable piece base 33.

The upper surface 31 a of the movable piece 31 is a first molding surface forming a first partial region 25 (a region connected to the inner surface 22 a) (see FIG. 6) of the first major surface 21 a of the resin molded product 20.
In FIG. 2, the movable piece 31 has a basic posture in which the upper surface 31 a is not inclined to the upper surface 36 a of the core main portion 32. Therefore, the upper surface 31a is along the XY plane. The basic posture is a posture in which the tip 34c of the protrusion 34 is most distant from the first mold 1 (see FIG. 1). In the basic posture, the rear side surface 33d is along the YZ plane.

  The projecting portion 34 projects forward (first direction) from the front side surface 33 c of the movable piece base 33 in the basic posture. The projecting direction of the projecting portion 34 is a direction (for example, a direction orthogonal to the Z direction) intersecting with the opposing direction (Z direction) of the first mold 1 and the second mold 2. The protrusion 34 may have a plate shape whose thickness direction is the Z direction in the basic posture.

  The front end surface 34 d of the protrusion 34 is a molding surface that forms the inner surface 23 a (see FIG. 6) of the base 23. The bottom surface 34 b of the protrusion 34 is a molding surface that forms the inner surface 24 a (see FIG. 6) of the extension 24. The protrusion 34 may be shaped so as to gradually decrease in thickness toward the tip 34 c.

The core main portion 32 includes a main body portion 36 and an extension portion 37.
The main body portion 36 is formed in a block shape. The upper surface 36a of the main body portion 36 is along the XY plane. An accommodation recess 38 for accommodating the movable piece base 33 of the movable piece 31 is formed at the front of the upper surface 36a.
The inner surface of the housing recess 38 has a main opposing surface 38 a facing the main outer surface 33 b of the movable piece base 33 and a rear side 38 b facing the rear side surface 33 d of the movable piece base 33.

The main opposing surface 38a has a main portion 38c along the XY plane, and a chamfered portion 38d inclined with respect to the main portion 38c. The main outer surface 33b of the movable piece 31 in the basic posture may abut on the main portion 38c.
The chamfered portion 38d is inclined downward from the front edge 38e of the main portion 38c (ie, in a direction away from the XY plane extending the main portion 38c as it goes forward). The chamfered portion 38 d can receive the lower portion of the movable piece base 33 in the most inclined posture.

  The rear side surface 38 b is preferably a flat surface inclined with respect to the YZ plane. The rear side surface 38b is inclined so as to gradually recede from the upper edge to the lower edge. Therefore, the gap between the rear side surface 33 d of the movable piece 31 in the basic posture and the rear side surface 38 b is larger toward the lower side.

The bottom surface 36 d of the main body 36 is formed with a recess 36 e in which the head 51 of the fixture 50 is accommodated. An insertion hole 40 into which the shaft 52 of the fixture 50 is inserted is formed on the top surface of the recess 36 e. The insertion hole 40 is a through hole reaching the main opposing surface 38a (specifically, the main portion 38c). The opening of the insertion hole 40 in the main opposing surface 38a is formed to reach the front edge 38e of the main portion 38c. The inner diameter of the insertion hole 40 is preferably larger than the outer diameter of the shaft 52.
The extension 37 extends obliquely downward from the bottom surface 36 d of the main body 36. The extension 37 is inclined to advance downward.

The fixture 50 includes a head 51 and a shaft 52 extending from the head 51. The fastener 50 is, for example, a screw fastener in which a screw is formed on the outer peripheral surface of the shaft 52. The shaft portion 52 is inserted into the insertion hole 40 of the core main portion 32, inserted into the insertion hole 35 of the movable piece 31, and screwed to the screw on the inner surface of the insertion hole 35. Thus, the movable piece 31 is attached to the core main portion 32 via the fixing tool 50.
53 is an annular elastic member (for example, a spring washer). The elastic member 53 is disposed between the head 51 and the recess 36e. The resilient member 53 is interposed between the head portion 51 and the recess 36e, so that the fixing tool 50 can be slightly moved up and down, so that the posture change of the movable piece 31 becomes easy.

  In the shaft portion 52, a portion connecting the main facing surface 38a and the main outer surface 33b is referred to as a "connection portion 41". The movable piece 31 is attached to the core main portion 32 by the connecting portion 41. Since the connecting portion 41 is formed by the shaft portion 52 of the fixing tool 50, the movable piece 31 is stably supported by the core main portion 32.

  Since the inner diameter of the insertion hole 40 is slightly larger than the outer diameter of the shaft 52, the shaft 52 can be slightly tilted. Therefore, the movable piece 31 can slightly change its posture in the direction in which it is inclined with the connecting portion 41 as a fulcrum.

  The posture of the movable piece 31 shown by the solid line in FIG. 2 is the basic posture, and the posture is such that the tip 34 c of the protrusion 34 is most distant from the first mold 1 (see FIG. 1). The posture of the movable piece 31 indicated by a virtual line is a posture (the most inclined posture) in which the tip 34 c of the protrusion 34 is closest to the first mold 1. In the most inclined posture, the upper surface 31 a of the movable piece 31 is inclined with respect to the upper surface 36 a of the main body portion 36. That is, the upper surface 31a of the movable piece 31 inclines so as to gradually descend toward the tip 34c. The movable piece 31 can switch between a basic posture shown by a solid line and a most inclined posture shown by a virtual line.

  The longitudinal position (X direction position) of the center 41a (the center in the cross section along the main outer surface 33b) of the connecting portion 41 is the same as the longitudinal position of the center 39 of the range of the main outer surface 33b in the front to back direction It is preferable to be closer to the front than the direction position. As a result, the movable piece 31 can be easily tilted, and a large fluctuation range of the posture of the movable piece 31 can be secured.

  As shown in FIG. 1, the inner surface 2 a of the second mold 2 is a main molding surface for molding the second main surface 21 b (see FIG. 6) of the main body 21 of the resin molded product 20.

Next, a molding method using the injection molding die 10 will be described with reference to FIGS. 3 to 5.
As shown in FIG. 3, the molten resin 60 is introduced into the void portion 4 of the injection molding die 10. The resin 60 is filled in the void 4. A portion of the resin 60 is filled between the outer surface forming recess 11 and the protrusion 34. As the resin 60, for example, polyolefin resin, polystyrene resin, ABS resin, polycarbonate resin, polyamide resin, etc. can be used.

  When the pressure of the resin 60 is increased for holding pressure, a large downward pressing force is applied to the core main portion 32 of the inclined core 3. On the other hand, since the lower surface side of the protrusion 34 is also filled with the resin 60, the downward pressing force does not become so large. Thus, a difference occurs in the pressing force applied to the core main portion 32 and the projecting portion 34, and bending stress may act on the inclined core 3 due to the difference.

  Next, the resin 60 is cured by cooling or the like. The resin 60 may be cooled using a refrigerant such as water or air, or may be allowed to cool. When the pressure of the resin 60 decreases due to cooling, the pressing force applied to the core main portion 32 decreases. The solidified resin 60 becomes a resin molded product 20 (see FIG. 6). The resin 60 between the main molding surface 1 b and the inner surface 2 a is the main body 21. The resin 60 between the outer surface forming recess 11 and the protrusion 34 serves as the clip seat 22.

  As shown in FIGS. 4 and 5, the second mold 2 and the inclined core 3 are moved together with the resin molded product 20 in a direction away from the first mold 1. At this time, since the inclined core 3 is retracted according to the inclination of the extension 37, the projection 34 is pulled out of the clip seat 22. Thus, a resin molded product 20 shown in FIG. 6 is obtained.

  In the injection molding die 10, the movable piece 31 can change its posture. Therefore, the bending stress applied to the protrusion 34 by the pressure of the resin 60 can be alleviated by the change in the posture of the movable piece 31. For example, as shown in FIG. 2, even when a downward bending stress is applied to the projecting portion 34 of the movable piece 31, the projection is performed by changing the posture so that the movable piece 31 is inclined as shown by a virtual line. The bending stress acting on the portion 34 is reduced. Therefore, damage to the protrusion 34 can be prevented.

In the injection molding die 10, since the protrusion 34 is not easily damaged, the protrusion 34 can be formed thin. Therefore, the clip seat 22 (see FIG. 6) having a low height can be formed. Thus, since there are few restrictions in the height dimension of the clip seat 22, etc., the freedom degree of the design of the resin molded product 20 is high.
Therefore, in the injection molding die 10, the inclined core 3 is not easily damaged, and the design freedom of the resin molded product 20 can be enhanced.
Further, in the injection molding die 10, since the movable piece 31 is separate from the core main portion 32, replacement of the movable piece 31 is easy. Therefore, the injection mold 10 is excellent also in terms of maintainability.

  In the injection molding die 10, since the chamfered portion 38d for receiving a part of the movable piece 31 in the most inclined posture is formed on the main opposing surface 38a, the fluctuation range of the posture of the movable piece 31 can be secured large. Therefore, the bending stress applied to the projecting portion 34 by the pressure of the resin 60 can be alleviated by the change in posture of the movable piece 31, and the damage of the projecting portion 34 can be prevented.

  The movable piece 31 is provided with a movable piece base 33 and a projection 34 projecting from the movable piece base 33. Even when the movable piece 31 is formed in a thin plate shape, the movable piece base 33 can be designed to give sufficient mechanical strength as a block shape. Therefore, by adopting a structure in which the movable piece base 33 is attached to the core main portion 32, the durability of the movable piece 31 can be enhanced.

In order to clarify the function and effect of the injection molding die 10, a molding method in the case of using the injection molding die of the comparative embodiment will be described.
FIGS. 7A to 7D are explanatory views showing a molding method using the injection mold 110 according to the comparative embodiment.
As shown in FIG. 7A, the injection mold 110 is implemented in that the inclined core 103 is an integral structure having a core main portion 132 and a projecting portion 134 protruding from the core main portion 132. It differs from the injection molding die 10 (see FIG. 1) in the form.

  As shown in FIG. 7B, the void portion 104 of the injection mold 110 is filled with the melted resin 60. A portion of the resin 60 is also filled between the outer surface forming recess 11 and the protrusion 134.

  As shown in FIG. 7C, when the pressure of the resin 60 is increased for holding pressure, a large downward pressing force (see the arrow) is applied to the core main portion 132 of the inclined core 103. As a result, the core main portion 132 may be slightly displaced downward. On the other hand, since the lower surface side of the protrusion 134 is also filled with the resin 60, the downward pressing force does not become so large. Furthermore, since the resin 60 exists above the protrusion 134, it is also difficult for the protrusion 134 to tilt as the core main portion 132 is tilted. Therefore, the protrusion 134 hardly displaces. Thus, bending stress may act on the inclined core 103 due to the difference in pressing force applied to the core main portion 132 and the projecting portion 134.

  As shown in FIG. 7D, when the pressure of the resin 60 is reduced by cooling, the force applied to the core main portion 132 is reduced. The downward displacement of the core main portion 132 is recovered. Also in this case, bending stress may act on the inclined core 103.

  As described above, in the injection molding die 110, bending stress can act on the inclined core 103 (particularly, the projecting portion 134) due to the difference in pressing force applied to the core main portion 132 and the projecting portion 134. There is sex. When the injection mold 110 is used repeatedly, the bending stress acts on the protrusion 134 multiple times. Therefore, damage due to metal fatigue is likely to occur in the protrusion 134.

(Modification)
Next, a modification of the inclined core 3 shown in FIG. 2 will be described.
In the inclined core 3 shown in FIG. 2, the main opposing surface 38a of the core main portion 32 has the main portion 38c and the chamfered portion 38d which is inclined with respect to the main portion 38c, but as shown in FIG. May be formed not on the main opposing surface of the core main portion but on the main outer surface of the movable piece.

FIG. 8 is a cross-sectional view of an inclined core 203 which is a modification of the inclined core 3. The same components as those of the inclined core 3 shown in FIG.
The entire main opposing surface 238 a of the accommodation recess 238 of the core main portion 232 is along the XY plane.
The main outer surface 233b which is the bottom surface of the movable piece base 233 of the movable piece 231 has a main portion 233e along the XY plane in the basic posture and a chamfered portion 233f inclined with respect to the main portion 233e.

  In the basic posture, the chamfered portion 233 f is inclined so as to rise from the front edge 233 g of the main portion 233 e toward the front (that is, in a direction away from the XY plane extending the main portion 233 e toward the front) . Since the movable piece base 233 has the chamfered portion 233f, the main opposing surface 238a does not hinder the tilting. Therefore, the fluctuation range of the posture of the movable piece 231 can be secured large. Therefore, in the inclined core 203, as in the case of the inclined core 3 shown in FIG. 2, the bending stress applied to the protrusion 34 at the time of molding can be alleviated by the posture change of the movable piece 231, and the damage of the protrusion 34 can be prevented.

The technical scope of the present invention is not limited to the above-described embodiments, and includes the above-described embodiments with various changes added thereto, without departing from the spirit of the present invention. That is, the configurations and the like described in the above-described embodiment are merely examples, and can be appropriately changed.
For example, the first mold 1 shown in FIG. 1 has a molding surface for molding the outer surface 22 b of the clip seat 22 (undercut structure) and a part of the first main surface 21 a of the main body 21. The mold 1 may have a molding surface for molding at least the outer surface of the undercut structure. The inclined core 3 (moving core) shown in FIG. 1 has a forming surface for forming the inner surface 22a of the clip seat 22 (undercut structure) and a part of the first main surface 21a of the main body 21 The core may have a molding surface for molding at least the inner surface of the undercut structure.

1 ... 1st type 2 ... 2nd type 3 ... inclined core (moving core)
DESCRIPTION OF SYMBOLS 10 ... Injection mold 20 ... Resin molded article 21 ... Main-body part 21a ... 1st main surface 21b ... 2nd main surface 22 ... Clip seat (undercut structure part)
22a: inner surface 22b: outer surface 25: first partial region 31, 131: movable piece 31a: upper surface (first molding surface)
32, 132: core main portion 33, 233: movable piece base 33b, 233b: main outer surface 34: protruding portion 34c: tip 38a, 238a: main opposing surface 38d: chamfered portion 39: central portion 41: connecting portion 50: fixing member F ... Forward (first direction)

Claims (5)

An injection molding die for molding a resin molded product having a main body having a first main surface and an undercut structure formed on the first main surface,
A first mold for molding at least the outer surface of the undercut structure;
A moving core forming at least the inner surface of the undercut structure;
And a second mold for molding a second main surface which is a surface opposite to the first main surface of the main body portion,
The movable core includes a movable piece having a protrusion for forming the inner surface of the undercut structure, and a core main portion which is separate from the movable piece.
The movable mold is attached to the core main portion so as to allow posture change in a direction in which the tip end of the protrusion approaches and separates from the first mold. The protrusion protrudes in a first direction with respect to the core main portion,
The movable piece has a first molding surface for molding a first partial region continuous with the inner surface of the undercut structure in the first main surface,
The core main portion has a main facing surface facing the main outer surface which is a surface opposite to the first molding surface of the movable piece,
The injection molding die according to claim 1, wherein the main opposing surface is chamfered so as to receive a part of the movable piece in a posture in which the tip end of the protrusion is closest to the first mold. The movable piece is attached to the core main portion at a connection portion connecting the main outer surface and the main opposing surface.
The injection molding mold according to claim 2, wherein the position of the connecting portion in the first direction is the same as the center of the range in the first direction of the main outer surface, or is closer to the first direction from the center. .   The injection molding mold according to claim 3, wherein the connecting portion is formed by a fixing tool inserted from the core main portion to the movable piece. The movable piece further comprises a movable piece base,
The main outer surface is formed on the movable piece base,
The injection mold according to any one of claims 2 to 4, wherein the projection protrudes in the first direction with respect to the movable piece base.

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