JPWO2018180824A1 - Undercut treatment mechanism, molding die and molded product - Google Patents

Abstract

Provided are an undercut processing mechanism, a molding die, and a molded product that can be easily cut out of an undercut portion while being compact and simply configured. An undercut which is attached to and used in a molding die 1 for molding a molded product P having an undercut portion P1 and which can undermold an undercut portion P1 protruding in a direction intersecting with a direction in which the molded product P is released. The processing mechanism 10 includes a holder 20 fixed or integrated with the molding die 1 and a molding portion 32 for molding the undercut portion P1 so that the molding portion 32 comes off the undercut portion P1. The sliding piece 30 slidable with respect to the holder 20 and the sliding piece 30 slidably held with respect to the holder 20 so as to be able to advance and retreat in a direction intersecting with the die-cutting direction of the molded product P. A holding piece 50 and an angular pin 12 for moving the holding piece 50 forward and backward are provided.

Description

  The present invention relates to an undercut mechanism, a molding die, and a molded product which are attached to and used in a molding die for molding a molded product having an undercut portion.

  In a molding die for molding a molded product having an undercut portion, many undercut treatment mechanisms have been developed in a form corresponding to the form of the undercut portion. As the undercut processing mechanism, for example, a mechanism called a loose core is generally used.

  Also, when molding a molded product that is difficult to mold with an undercut processing mechanism using a conventional loose core, for example, when molding a molded product in which a boss having a hollow portion protrudes in a direction that intersects with the die-cutting direction of the entire molded product, The present applicant has already proposed an undercut processing mechanism that allows a boss serving as an undercut portion to be easily die-cut (for example, see Patent Document 1).

  The undercut processing mechanism described in Patent Literature 1 includes a holder provided in a fixed mold or a movable mold of a molding die, and a molding core for molding an undercut portion. The first core and the second core have side surfaces which are inclined adjacent to each other, and the undercut portion can be die-cut by sliding in the holder along the side surfaces.

JP 2010-155381 A

  According to the undercut processing mechanism described in Patent Literature 1, it is easy to form a molded product having a shape that was difficult to form using an undercut processing mechanism using a conventional loose core, and a support rod and a guide rod are not required. Thus, it can be configured more compactly than the conventional undercut processing mechanism using a loose core.

  The present invention realizes easy and compact molding of a molded article having an undercut portion like the undercut processing mechanism described in Patent Document 1 in a configuration different from the undercut processing mechanism described in Patent Document 1. The present invention proposes a possible undercut processing mechanism, a molding die, and a molded product.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an undercut processing mechanism, a molding die, and a molded product that can be easily formed into a compact shape while easily undercutting an undercut portion.

  The present invention provides an undercut which is used by being attached to a molding die for molding a molded product having an undercut portion and which is capable of removing the undercut portion protruding in a direction intersecting with a direction in which the molded product is removed. A cut processing mechanism, comprising a holder fixed or integrally formed with the molding die, and a molding portion for molding the undercut portion, wherein the molding portion is detached from the undercut portion. A sliding piece slidable with respect to the holder, and a holding piece slidably holding the sliding piece slidable with respect to the holder in a direction intersecting with a direction in which the molded product is removed. A driving means for moving the holding piece forward and backward, wherein the holding piece moves via the driving means in conjunction with opening of the molding die, so that the molding portion is moved from the undercut portion. I'm off It is undercut processing mechanism, characterized in that the sliding piece is configured to move.

  In the undercut processing mechanism of the present invention, the driving means is an inclined member attached to the molding die so as to be inclined with respect to a direction in which the molding die is opened and closed. The member engages with the holding piece without engaging with the holder, and the holding piece advances and retreats via the inclined member in conjunction with opening and closing of the molding die. And

  Further, in the undercut processing mechanism of the present invention, the driving means is a cylinder and / or an electromagnet connected to the holding piece, and the holding piece can advance and retreat via the cylinder and / or the electromagnet. I do.

  Further, in the undercut processing mechanism of the present invention, the driving unit includes a first pressing unit and a second pressing unit, and the holding piece is moved by the action of the first pressing unit when the molding die is opened. When the mold is closed, the holding piece moves in a direction opposite to that when the mold is opened by the action of the second pressing means.

  Further, in the undercut processing mechanism of the present invention, the first pressing means is a spring, and the second pressing means is attached to the molding die, and the mold opening and clamping of the molding die are performed. It is a piece having a slope inclined with respect to the direction, and the slope is slidably engaged with the holding piece.

  Further, in the undercut processing mechanism of the present invention, the second pressing means is a forced tension piece having a claw that engages with the holding piece at a bottom portion, and the holding piece is used when the molding die is clamped. A claw is fitted in the fitting groove, and the forcible tension piece forcibly moves the holding piece when the mold is opened through the claw engaging with the fitting groove. I do.

  Further, in the undercut processing mechanism of the present invention, the molded portion has a tapered outer shape in which a distal end portion is thinner than a base end portion.

  Further, in the undercut processing mechanism of the present invention, each of the holder and the holding piece regulates a moving direction of the sliding piece when the molding die is opened in a direction in which the molding portion comes off from the undercut portion. It is characterized by having a regulation means.

  Further, in the undercut processing mechanism of the present invention, the holder is capable of partially or completely storing the sliding piece and / or the holding piece.

  Further, in the undercut processing mechanism of the present invention, the sliding piece is a molding member for molding the hollow portion or the space portion of the undercut portion so that the molded product having the hollow portion or the space portion in the undercut portion can be molded. It is characterized by having.

  The present invention is a molding die including the undercut treatment mechanism.

  The present invention is a molded product molded by the undercut treatment mechanism or the molding die.

  According to the undercut processing mechanism and the molding die of the present invention, the holding piece and the sliding piece are housed in the holder, and the driving means moves the holding piece in conjunction with the opening of the molding die, Since the sliding piece that engages with the holding piece moves so as to be disengaged from the undercut portion, the undercut portion can be easily die-cut while being compact and simple.

FIG. 2 is a cross-sectional view of the molding die 1 according to the first embodiment of the present invention when the mold is clamped. FIG. 2 is a cross-sectional view of the molding die 1 according to the first embodiment of the present invention after the mold is opened. FIG. 2 is a cross-sectional view of the molding die 1 according to the first embodiment of the present invention after the molded product P is ejected. FIG. 2 is an enlarged view of a peripheral portion of an undercut processing mechanism 10 in FIG. 1. FIG. 3 is an enlarged view of a peripheral portion of an undercut processing mechanism 10 in FIG. 2. 1 is a perspective view of an undercut processing mechanism 10 of a molding die 1 according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of an undercut processing mechanism 10 of the molding die 1 according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view of a molding die 2 according to a second embodiment of the present invention when the mold is clamped. It is sectional drawing after opening of the metal mold | die 2 for molding of 2nd Embodiment of this invention. It is sectional drawing after the protrusion operation | movement of the molded article P of the shaping | molding die 2 of 2nd Embodiment of this invention. It is the perspective view which looked at the undercut processing mechanism 11 of the metallic mold 2 of a 2nd embodiment of the present invention from the front upper part. It is the perspective view which looked at the undercut processing mechanism 11 of the metallic mold 2 of a 2nd embodiment of the present invention from the rear upper part. FIG. 7 is an exploded perspective view of an undercut processing mechanism 11 of a molding die 2 according to a second embodiment of the present invention, as viewed from the upper front. It is the disassembled perspective view which looked at the undercut processing mechanism 11 of the shaping | molding die 2 of 2nd Embodiment of this invention from upper rear. It is sectional drawing at the time of the mold clamping of the shaping | molding die 3 of 3rd Embodiment of this invention. It is sectional drawing after opening of the metal mold | die 3 for molding of 3rd Embodiment of this invention. FIG. 2 is a perspective view showing an example of a molded product that can be molded by an undercut processing mechanism and a molding die of the present invention.

  1, 2, and 3 are a cross-sectional view of the molding die 1 according to the first embodiment of the present invention at the time of mold clamping, a cross-sectional view of the molding die 1 after opening, and a molding die 1, respectively. FIG. 7 is a cross-sectional view of the molded product P after the protrusion operation. FIG. 4 is an enlarged view of a peripheral portion of the undercut processing mechanism 10 in FIG. 1, and FIG. 5 is an enlarged view of a peripheral portion of the undercut processing mechanism 10 in FIG. 6 and 7 are a perspective view of the undercut processing mechanism 10 of the molding die 1 and an exploded perspective view of the undercut processing mechanism 10 of the molding die 1 according to the first embodiment of the present invention. 1 to 6, only the holder 20 of the undercut processing mechanism 10 is shown in a sectional view. In FIGS. 1 to 3, reference numerals are partially omitted.

  The molding die 1 according to the first embodiment of the present invention includes a fixed die 100 for injecting a molding material to form an outer surface side of a molded product P (see FIG. 1), and an inner surface including an undercut portion P1 of the molded product P. It has the same configuration as a known injection mold having a movable mold 101 for molding the side, but differs from the known injection mold in that an undercut treatment mechanism 10 is provided. Note that, for convenience, the fixed mold 100 side in FIG.

  In the molding die 1 of the first embodiment, similarly to a known injection molding die, a fixed die 100 includes a fixed-side mounting plate 103, a fixed-side die plate 104, a locate ring 105, and a sprue bush 106. 101 includes a movable-side mounting plate 107, a movable-side mold plate 108, a spacer block 109, two ejector base plates 110, an ejector pin 111, a return pin 112, a spring 113, and an ejector rod 114. The ejector pin 111 moves the ejector base plate 110 relative to the movable mold plate 108 in the direction of removing the molded product P (upward in FIG. 1), so that the ejector pins 111 perform the projecting operation of the molded product P. Note that the above components are the same as known injection molding dies, and a description thereof will be omitted.

  In the molding die 1 of the first embodiment, an undercut processing mechanism 10 that enables the undercut portion P1 to be die-cut is incorporated in a movable die 101, and a holding piece of the undercut processing mechanism 10 described later is provided. An angular pin 12, which is an inclined member for moving the mold 50 forward and backward in conjunction with the mold clamping and mold opening of the molding mold 1, is inclined with respect to the mold clamping and mold opening direction of the molding mold 1 (vertical direction in FIG. 1). To be fixed to the fixed side template 104.

  The undercut processing mechanism 10 forms the undercut portion P1 at the time of molding the molded product P, and separates from the undercut portion P1 when the molding die 1 is opened. The cut portion P1 can be removed from the molding die 1.

  In the present embodiment, the undercut portion P1 is a cylindrical boss that protrudes from the inner surface side of the molded product P in a direction intersecting the die-cutting direction of the molded product P (upward in FIG. 1). In the undercut treatment mechanism, the molding die, and the molded product of the present invention, the undercut portion that can be formed and removed from the mold is not limited to the cylindrical boss as described later. Further, the material of the molded article P is not limited to a synthetic resin such as plastic, but may be a metal such as iron, copper, or aluminum.

  The undercut processing mechanism 10 includes a holder 20 embedded and fixed in the movable mold plate 108, a sliding piece 30 having a forming part 32 for forming the undercut part P1 of the molded product P, and the sliding piece 30. A holding piece 50 slidably held, and the sliding piece 30 and the holding piece 50 slide with respect to the holder 20 via the angular pin 12 in conjunction with the opening and closing of the molding die 1. The molding portion 32 of the sliding piece 30 forms the undercut portion P1 when the molding die 1 is clamped, and the molding portion 32 of the sliding piece 30 is formed when the molding die 1 is opened. Operates so as to come off the undercut portion P1.

  The holder 20 is buried in the movable mold plate 108 of the movable mold 101, partially accommodates the sliding piece 30 and the holding piece 50, and regulates the moving direction of the sliding piece 30 and the holding piece 50. The holder 20 is a U-shaped member in a plan view. The holder 20 has an oblique groove 22 as a restricting means for restricting the moving direction of the sliding piece 30 and a horizontal groove 24 as a restricting means for restricting the moving direction of the holding piece 50. On both inner surfaces facing each other.

  The inclined groove 22 is slidably fitted with a ridge 44 of the sliding piece 30 described later, and the moving direction of the sliding piece 30 is adjusted by the forming portion 32 of the sliding piece 30 when the molding die 1 is opened. The molding die 1 is provided so as to be inclined with respect to the mold opening direction so as to be restricted in a direction away from the undercut portion P1. Here, the direction in which the molded portion 32 of the sliding piece 30 is disengaged from the undercut portion P1 is defined as a sliding piece in which the molded portion 32 of the sliding piece 30 is disengaged from the undercut portion P1 without deforming or damaging the undercut portion P1. This is the direction in which the sliding piece 30 moves away from the undercut portion P1, which coincides with the central axis of the cylindrical boss (undercut portion P1) in the present embodiment.

  The horizontal groove 24 is provided so that a first ridge 52 of a holding piece 50 to be described later is slidably fitted therein and regulates the moving direction of the holding piece 50 in the horizontal direction (left-right direction in FIG. 1). . Note that the moving direction of the holding piece 50 is not limited to the horizontal direction. Instead of the horizontal groove 24, an inclined groove inclined with respect to the horizontal direction may be provided in the holder 20.

  The shape of the holder 20 is not limited to a specific shape, and the sliding piece 30 and the holding piece 30 are held so that the molded portion 32 of the sliding piece 30 comes off the undercut portion P1 when the mold 1 is opened. It is only necessary that the movement direction of the piece 50 can be regulated. Further, the holder 20 may be formed by being divided into a plurality of members, or may be formed integrally with the movable mold plate 108.

  The sliding piece 30 includes a forming part 32 that forms the undercut part P1, a sliding part 36 that slides with respect to the holder 20 and the holding piece 50, and a shaft part 38 that connects the forming part 32 and the sliding part 36. And The molded portion 32, the pin 34, the sliding portion 36, and the shaft portion 38 may be integrally formed, and a part or all of them may be formed as one member so that the sliding piece 30 can be formed. May be.

  The forming part 32 is a trapezoid block, has a hollow part 42 for forming the undercut part P1 on the upper surface 40, and has a pin 34 for forming the hollow part of the undercut part P1 in the hollow part 42. In the molded portion 32, the exposed surfaces of the upper surface 40, the hollow portion 42, and the pins 34 serve as a molded surface for molding a part of the molded product P and the undercut portion P1. For this reason, the molding part 32 is formed and arranged so that no gap is formed between the upper surface 40 and the upper surface of the movable mold plate 108 during mold clamping in order to prevent molding failure of the molded product P.

  The pin 34 is a cylindrical shaped member that forms the hollow portion of the undercut portion P1. The pin 34 is arranged in the hollow portion 42 of the forming portion 32 so as to form the hollow portion of the undercut portion P1 and is fixed to the forming portion 32 via a fixing shaft member 43.

  The sliding portion 36 is a trapezoidal block, and is provided on a side surface in contact with the inner surface of the holder 20 where the oblique groove 22 is provided. The holding piece 50 has a dovetail groove 46 that slidably engages with the second projection 54.

  The shaft portion 38 has a cylindrical shape and stands upright from the lower surface of the molded portion 32. The shaft part 38 is fixed to the upper surface of the sliding part 36 by a bolt 48.

  The shapes of the molded portion 32, the pin 34, the sliding portion 36, and the shaft portion 38 are not limited to specific shapes, and may be appropriately changed according to the shape of the molded product P and the like.

  The holding piece 50 is a trapezoidal block. The holding piece 50 is provided on a side surface in contact with the inner surface of the holder 20 where the horizontal groove 24 is provided. The first protrusion 52 is slidably fitted in the horizontal groove 24, and is provided on an inclined surface. The dovetail groove 46 of the sliding piece 30 is slidably engaged with the second convex ridge 54, and has an inclined hole 56 pierced from the upper surface to the lower surface and through which the angular pin 12 is inserted.

The inclination angles θ ₁ and θ ₂ (see FIG. 4) of the inclined surface provided with the second convex strip 54 and the inclined hole 56 through which the angular pin 12 is inserted are determined by the stroke of the molding die 1 (movable die 101) and Based on the dimensions of the undercut portion P1, the molding portion 32 of the sliding piece 30 is determined to be separated from the undercut portion P1 when the mold is opened.

Note Increasing the inclination angle theta ₁ with respect to the horizontal direction of the second projections 54 (horizontal direction in FIG. 1), the amount of movement of the sliding piece 30 is increased relative to the amount of movement of the holding frame 50. Also when increasing the inclination angle theta ₂ with respect to the vertical direction of the inclined hole 56 (the vertical direction in FIG. 1), the amount of movement of the holding frame 50 with respect to the amount of movement of the movable mold 101 is increased.

  The holding piece 50 and the movable mold plate 108 are provided with through holes 58 and 120 through which bolts 48 connecting the shaft portion 38 and the sliding portion 36 of the sliding piece 30 can be inserted. Thus, after the holder 20, the sliding piece 30, and the holding piece 50 are assembled into the movable mold plate 108, the sliding portion 36 and the shaft portion 38 can be fixed by passing the bolts 48 through the insertion holes 58, 120. it can.

  Next, the operation of the molding die 1 of the first embodiment will be described. When molding the molded product P, the molding material is injected from the sprue bush 106 of the fixed mold 100 in a state where the molding die 1 is clamped, and the molded material is cured to form the molded product P (see FIGS. 1 and 4). . At the time of molding, the upper surface 40 of the molding portion 32 of the sliding piece 30 of the undercut processing mechanism 10 is flush with the upper surface of the movable mold plate 108 to contact the molded product P (molding material) to perform molding. The hollow surface 42 and the exposed surface of the pin 34 form the undercut portion P1 of the molded product P.

  After the molding of the molded product P, the mold 1 is opened. When the molding die 1 is opened, the entire movable die 101 moves downward in FIG. In conjunction with this, the holding piece 50 retreats (moves rightward in FIG. 1) along the horizontal groove 24 of the holder 20 by the action of the inclined hole 56 and the angular pin 12, and the sliding piece 30 is thereby moved. Due to the action of 46 and the second ridge 54 of the holding piece 50, it moves along the oblique groove 22 of the holder 20, whereby the molded portion 32 of the sliding piece 30 comes off the undercut portion P1 (see FIGS. 2 and 5). ).

  After the mold 1 is opened, the molded product P is ejected. During the ejecting operation of the molded product P, the ejector base plate 110 moves upward in FIG. 1, and the molded product P is ejected from the movable mold plate 108 by the ejector pins 111 (see FIG. 3).

  After taking out the molded product P, the molding die 1 is clamped again so as to form the next molded product P. During mold clamping, the entire movable mold 101 moves upward in FIG. 3, and the ejector base plate 110 moves downward in FIG. The undercut processing mechanism 10 moves the holding piece 50 forward along the horizontal groove 24 of the holder 20 by the action of the inclined hole 56 and the angular pin 12 in association with the movement of the movable mold 101 (moves to the left in FIG. 3). Accordingly, the sliding piece 30 moves along the oblique groove 22 of the holder 20 by the action of the dovetail groove 46 and the second convex ridge 54 of the holding piece 50, and the upper surface 40 of the molded portion 32 of the sliding piece 30 is moved. It is flush with the upper surface of the movable mold plate 108. When the mold clamping is completed, the molding material is injected and the next molded article P is molded.

  As described above, according to the molding die 1 and the undercut processing mechanism 10 of the first embodiment, the holding piece 50 slides with respect to the holder 20 in conjunction with the opening of the molding die 1. Since the sliding piece 30 slides with respect to the holder 20 and moves so as to be disengaged from the undercut portion P1, the undercut portion P1 can be easily cut out while being compact and simple.

  Further, according to the undercut processing mechanism 10 of the first embodiment, the sliding piece 30 and the holding piece 50 can be assembled into the molding die 1 in a state of being partially accommodated in the holder 20, so that the compact structure is achieved. It is possible and easy to attach to the molding die 1. Further, for example, it is also possible to configure so that the sliding piece 30 and the holding piece 50 are completely stored in the holder 20 at the time of mold clamping.

  According to the molding die 1 and the undercut processing mechanism 10 of the first embodiment, the undercut processing mechanism 10 operates in conjunction with the opening and closing of the molding die 1 via the angular pin 12. Therefore, the undercut portion P1 can be die-cut without providing a complicated drive mechanism or the like. Further, since the angular pin 12 which is a driving means for moving the holding piece 50 forward and backward does not engage with the holder 20, the holder 20 is simplified, and the undercut processing mechanism 10 can be made compact.

  8, 9, and 10 are a cross-sectional view of the molding die 2 according to the second embodiment of the present invention at the time of clamping, a cross-sectional view of the molding die 2 after opening, and a molding die 2. FIG. 7 is a cross-sectional view of the molded product P after the protrusion operation. FIGS. 11 and 12 are a perspective view of the undercut processing mechanism 11 of the molding die 2 according to the second embodiment of the present invention as viewed from the upper front and a perspective view as viewed from the upper rear. 11 and 12, a part of the holder 20 is cut away. FIGS. 13 and 14 are an exploded perspective view of the undercut processing mechanism 11 of the molding die 2 according to the second embodiment of the present invention as viewed from the front upper side and an exploded perspective view as viewed from the rear upper side. The same components as those of the molding die 1 of the first embodiment of the present invention shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted.

  The molding die 2 according to the second embodiment of the present invention has the same basic configuration as the molding die 1 according to the first embodiment of the present invention, but the undercut processing mechanism 11 uses the undercut processing according to the first embodiment. Different from the mechanism 10. Accordingly, the configuration of the movable mold 101 is partially different, but the basic configurations of the fixed mold 100 and the movable mold 101 of the molding die 2 are the same as those of the molding die 1 of the first embodiment. Hereinafter, the undercut processing mechanism 11 of the second embodiment will be described in detail. Note that, for convenience, the fixed mold 100 side in FIG.

  The undercut processing mechanism 11 is an undercut processing mechanism that enables the undercut portion P1 to be die-cut. The undercut processing mechanism 11 is incorporated in the movable die 101, and the undercut portion P1 is formed from the inner side of the molded product P. This is the same as the undercut processing mechanism 10 of the first embodiment in that it is a cylindrical boss protruding in a direction intersecting the die-cutting direction (upward in FIG. 8).

  Further, in the undercut processing mechanism 11, the molding die 2, and the molded product P, the undercut portion P1 that can be molded and removed is not limited to the cylindrical boss, and the material of the molded product P is a synthetic resin such as plastic. However, the present invention is not limited to this, and is common to the undercut processing mechanism 10 and the molding die 1 of the first embodiment in that a metal such as iron, copper, or aluminum may be used.

  The undercut processing mechanism 11 is common in many parts to the undercut processing mechanism 10 of the first embodiment also in the configuration, but firstly, the holding piece is interlocked with the clamping and opening of the molding die. The driving means for moving forward and backward is different. Secondly, the shapes of a part of the molded product P and the molded part 32 for molding the undercut part P1 are different.

  The undercut processing mechanism 11 includes a holder 20 embedded and fixed in the movable mold plate 108, a sliding piece 31 having a forming part 32 for forming the undercut part P <b> 1 of the molded product P, and the sliding piece 31. And a holding piece 51 slidably held. Further, a spring 70 as a driving means for moving the holding piece 51 along the horizontal groove 24 of the holder 20, a forced tension piece 80, and a stopper 90 are provided.

  The holder 20 is embedded in the movable mold plate 108 of the movable mold 101 in the same manner as the holder 20 of the undercut processing mechanism 10 of the first embodiment, and the bottom of the holder 20 is attached to the bottom of the movable mold plate 108. Is supported by the movable side receiving plate 115. The holder 20 of the undercut processing mechanism 11 of the present embodiment is the same as the holder 20 of the undercut processing mechanism 10 of the first embodiment, including the basic shape, configuration, function, and the like. Like the holder 20 of the undercut processing mechanism 10 of the first embodiment, the holder 20 of the present embodiment is not limited to a specific shape, and may be formed by being divided into a plurality of members. It may be formed integrally with the template 108.

  The sliding piece 31 of the undercut processing mechanism 10 according to the first embodiment is provided with a forming part 32 that forms the undercut part P1 and a sliding part 36 that slides with respect to the holder 20 and the holding piece 51. Although common to the sliding piece 30, the sliding piece 31 does not have the shaft portion 38, and the molded portion 32 and the sliding portion 36 are integrally formed. However, the sliding piece 31 may have the shaft portion 38 similarly to the sliding piece 30, or may be configured by connecting a plurality of members.

  The forming part 32 is a trapezoid block. More specifically, the cross section of the molded portion 32 is rectangular, and the front surface 33 and the rear surface 35 which are surfaces intersecting with the horizontal grooves 24 of the holder 20 are inclined when viewed in the height direction, and head upward. And the cross-sectional area gradually decreases. By making the outer shape of the molded portion 32 thinner at the distal end as compared with the base end as described above, the slidability with the movable mold 108 can be improved, and seizure and galling can be prevented.

  The tapered structure of the outer shape of the molded portion 32 only needs to have a smaller cross-sectional area at the distal end portion than at the base end portion, and the inclined surface may be any surface. Therefore, instead of the front surface 33 and the rear surface 35, both side surfaces of the molded portion 32 may be inclined, or any one surface may be inclined, or all surfaces may be inclined surfaces.

  The forming portion 32 has a hollow portion 42 for forming the undercut portion P1 on the upper surface 40, and the hollow portion 42 has a hollow portion of the undercut portion P1 similarly to the forming portion 32 of the undercut processing mechanism 10 of the first embodiment. And a molding surface for molding a part of the molded product P and the undercut portion P1. In order to prevent molding failure of the molded product P, the upper surface 40 and the movable mold are closed at the time of mold clamping. It is formed and arranged so that no gap is formed between the upper surface of the plate 108.

  The structures, functions, and effects of the pin 34 and the sliding portion 36 are the same as those of the pin 34 and the sliding portion 36 of the undercut processing mechanism 10 of the first embodiment. The shapes of the molded portion 32, the pin 34, and the sliding portion 36 are not limited to specific shapes, and may be appropriately changed according to the shape of the molded product P and the like.

  The holding piece 51 is a trapezoidal block, and has a front face provided with an inclined face 59 on which the sliding portion 36 of the sliding piece 31 is slidably engaged, and a rear face provided with an inclined face 60 on which the forcible tension piece 80 slides. ing. The holding piece 51 is provided on a side surface in contact with the inner surface of the holder 20 where the horizontal groove 24 is provided, and is provided with a first ridge 52 slidably fitted in the horizontal groove 24 and a sliding piece 31 provided on the inclined surface 59. And a second ridge 54 with which the dovetail groove 46 is slidably engaged.

The angle of inclination θ ₁ of the inclined surface 59 (see FIG. 8) is determined by the stroke of the molding die 2 (movable die 101) and the dimensions of the undercut portion P1 when the molding portion 32 of the sliding piece 31 is opened when the mold is opened. It is determined so as to deviate from the undercut portion P1. Increasing the inclination angle theta ₁ with respect to the horizontal direction of the second projections 54 (horizontal direction in FIG. 8), the amount of movement of the sliding piece 31 is increased with respect to the amount of movement of the holding frame 51. These are the same as the undercut processing mechanism 10 of the first embodiment.

  The holding piece 51 has an accommodation hole 61 for accommodating the spring 70 at a lower portion on the front surface. The accommodation hole 61 is not a through hole. The number of the housing holes 61 is provided corresponding to the number of the springs 70, the inner diameter is set slightly larger than the outer diameter of the spring 70, and the length is set shorter than the length of the spring 70.

  At the lower end of the inclined surface 60 of the holding piece 51, there is provided a fitting groove 65 into which the claw 82 of the forcible pulling piece 80 is fitted without gap. The fitting groove 65 is formed in such a manner that a projection 66 inclined at the rear end side is provided.

  The spring 70 is a first pressing means in the present embodiment, and moves the holding piece 51 so as to retreat (to the right in FIG. 9). In the present embodiment, the springs 70 are composed of two compression coil springs, but the number is not particularly limited. Further, the length, diameter, and spring characteristics of the spring 70 are not particularly limited, and a spring suitable for the undercut processing mechanism 11 may be appropriately selected and used.

  The spring 70 is housed in the housing hole 61 of the holding piece 51, and when the molding die 2 is in the clamped state, one end is pressed against the inner wall surface of the holder 20 and the other end is pressed against the bottom 62 of the housing hole 61 to be compressed. Is accommodated in the accommodation hole 61. The spring 70 extends with the opening of the molding die 2 and retreats the holding piece 51.

  The forced tension piece 80 is a block-shaped piece provided with an inclined surface 81 from the center to the lower end of the front surface, and has a claw 82 connected to the lower end of the inclined surface 81 at the bottom of the front surface. The claw 82 is provided in the full width direction, and the front surface 83 of the claw 82 has the same inclination angle as the inclined surface 81 and is provided so as to be connected to the inclined surface 81. The back surface 84 of the claw 82 is also an inclined surface parallel to the front surface 83. The claw 82 is a member for forcibly separating the molding portion 32 from the undercut portion P1 when the molding die 2 is opened.

  The forced tension piece 80 has a projection 85 provided on the upper part fitted in a fitting groove provided on the fixed side mold plate 104 so that the inclined surface 81 and the inclined surface 60 of the holding piece 51 can slide with each other. Are fixed to the bottom of the fixed-side template 104 so as to be in contact with the fixed-side template 104. Such a forced tension piece 80 serves as a locking block for the holding piece 51, as a driving means (second pressing means) for advancing the holding piece 51 back into the holder 20, and further for opening the mold 2. At times, it acts as a means for forcibly separating the molded portion 32 from the undercut portion P1.

  The claw 82 of the forcible tension piece 80 and the fitting groove 65 of the holding piece 51 are not limited to the embodiment. The claw 82 and the fitting groove 65 are fitted into the fitting groove 65 so as to engage with each other when the mold is clamped, and are forcibly held when the mold is opened by the action of the engaging claw 82 and the fitting groove 65. It is only necessary that the piece 51 can be moved backward. Note that the moving amount (retreat amount) of the holding piece 51 by the claw 82 may be any value as long as the undercut portion P1 can prevent the sliding piece 31 from biting.

  The stopper 90 is a means for regulating the retreat amount of the holding piece 51. When the holding piece 51 retreats with the opening of the mold, the retreat amount of the holding piece 51 is regulated by contact of the rear end of the holding piece 51. You.

  Next, the operation of the molding die 2 of the present embodiment will be described. When molding the molded product P, the molding material is injected from the sprue bush 106 of the fixed mold 100 in a state where the molding die 2 is clamped, and the molded material is cured to form the molded product P (see FIG. 8). At the time of molding, the upper surface 40 of the molding portion 32 of the sliding piece 31 of the undercut processing mechanism 11 is flush with the upper surface of the movable mold plate 108 to contact the molded product P (molding material) to perform molding. The hollow portion 42 and the exposed surface of the pin 34 form the undercut portion P1 of the molded product P.

  After the molding of the molded product P, the mold 2 is opened. When the molding die 2 is opened, the entire movable die 101 moves downward in FIG. In conjunction with this, the holding piece 51 is forcibly retracted (moved to the right in FIG. 8) slightly along the horizontal groove 24 of the holder 20 by the action of the claw 82 of the forcible pulling piece 80. At the same time, the holding piece 51 retreats along the horizontal groove 24 of the holder 20 by the action of the spring 70. Along with this, the sliding piece 31 moves along the oblique groove 22 of the holder 20 by the action of the dovetail groove 46 and the second ridge 54 of the holding piece 51, whereby the forming portion 32 of the sliding piece 31 is moved to the undercut portion. It deviates from P1 (see FIG. 9).

  After the molding die 2 is opened, the molded product P is ejected. During the ejecting operation of the molded product P, the ejector base plate 110 moves upward in FIG. 8, and the molded product P is ejected from the movable mold plate 108 by the ejector pins 111 (see FIG. 10).

  After taking out the molded product P, the molding die 2 is clamped again so as to form the next molded product P. During mold clamping, the entire movable mold 101 moves upward in FIG. 10, and the ejector base plate 110 moves downward in FIG. The undercut processing mechanism 11 moves the holding piece 51 forward (moves leftward in FIG. 10) along the horizontal groove 24 of the holder 20 by the action of the forcible pulling piece 80 in conjunction with the movement of the movable die 101. As a result, the slide piece 31 moves along the oblique groove 22 of the holder 20 by the action of the dovetail groove 46 and the second ridge 54 of the holding piece 51, and the upper surface 40 of the molding portion 32 of the slide piece 31 is moved. It is flush with the upper surface of the plate 108. When the mold clamping is completed, the molding material is injected and the next molded article P is molded.

  As described above, according to the molding die 2 and the undercut processing mechanism 11 of the present embodiment, the holding piece 51 slides with respect to the holder 20 in conjunction with the opening of the molding die 2. Since the sliding piece 31 slides with respect to the holder 20 and moves so as to be disengaged from the undercut portion P1, the undercut portion P1 can be easily die-cut while being compact and simple.

  Further, according to the undercut processing mechanism 11 of the present embodiment, the sliding piece 31 and the holding piece 51 can be assembled into the molding die 2 in a state of being partially accommodated in the holder 20, so that the structure can be made compact. In addition, mounting to the molding die 2 is easy. Further, for example, it is also possible to configure so that the sliding piece 31 and the holding piece 51 are completely stored in the holder 20 at the time of mold clamping.

  Further, according to the molding die 2 and the undercut processing mechanism 11 of the second embodiment, the undercut processing mechanism is interlocked with the opening and closing of the molding die 2 via the spring 70 and the forced tension piece 80. 11, the undercut portion P1 can be die-cut without providing a complicated drive mechanism or the like.

  In the case of a molding die that uses a spring as a drive source for moving the holding piece, when the molded part of the sliding piece is in close contact with the undercut portion P1 and the spring cannot retract the holding piece even when the mold is opened. There is. In particular, in the case where the undercut portion P1 is a cylindrical boss protruding from the inner surface side of the molded product P in a direction intersecting with the direction in which the molded product P is removed as in the molded product P shown in the present embodiment. Since the contact area between the formed portion and the undercut portion P1 is large, the formed portion is less likely to bite into the undercut portion P1 and come off. If the undercut portion P1 does not come off in conjunction with the mold opening, the molded product P may be damaged.

  On the other hand, in the undercut processing mechanism 11 of the second embodiment, the claw 82 of the forcible tension piece 80 engaging with the projection 66 of the fitting groove 65 of the holding piece 51 holds the claw 82 when the mold 2 is opened. Since the piece 51 is forcibly retracted, the sliding piece 31 moves so as to come off the undercut portion P1. As a result, biting of the molded portion 32 to the undercut portion P1 is eliminated, so that the undercut portion P1 is removed by the force of the spring 70, and the molded product P can be collected without being damaged.

  When it is difficult for the undercut portion P1 to bite into the molded portion 32 due to the shape of the molded product P or the like, a piece obtained by removing the claw 82 from the forced tension piece 80 can be used. The piece having no claw 82 functions as a locking block, and also as a second pressing means for advancing the holding piece 51 back into the holder 20.

  Further, in the undercut processing mechanism 11 of the second embodiment, the slidability with the movable mold 108 is improved because the forming portion 32 of the sliding piece 31 is tapered upward, so that seizure and galling are prevented. Can be prevented. It is preferable that the forming part 32 of the sliding piece 30 according to the first and third embodiments to be described later is tapered similarly to the forming part 32 of the sliding piece 31 according to the second embodiment.

  FIG. 15 is a cross-sectional view of the molding die 3 of the third embodiment of the present invention at the time of mold clamping, and FIG. 16 is a cross-sectional view of the molding die 3 of the third embodiment of the present invention after the mold is opened. is there. The same components as those of the molding die 1 of the first embodiment of the present invention shown in FIGS. 1 to 7 and the molding die 2 of the second embodiment of the present invention shown in FIGS. 8 to 14 have the same reference numerals. And the description is omitted.

  The molding die 3 according to the third embodiment of the present invention has the same basic configuration as the molding die 1 according to the first embodiment of the present invention, but the undercut processing mechanism 15 uses the undercut processing according to the first embodiment. Different from the mechanism 10. The basic configurations of the fixed die 100 and the movable die 101 of the molding die 3 are the same as those of the molding die 2 of the second embodiment. Hereinafter, the undercut processing mechanism 15 of the third embodiment will be described in detail. For convenience, the description will be made with the fixed mold 100 side in FIG.

  The undercut processing mechanism 15 is an undercut processing mechanism that enables the undercut portion P1 to be die-cut. The undercut processing mechanism 15 is incorporated in the movable die 101. 15 is common to the undercut processing mechanism 10 of the first embodiment and the undercut processing mechanism 11 of the second embodiment in that I do.

  In the undercut processing mechanism 15, the molding die 3, and the molded product P, the undercut portion P1 that can be molded and removed is not limited to a cylindrical boss, and the molded product P is made of synthetic resin such as plastic. However, the present invention is not limited to this, and may be common to the undercut processing mechanism 10 of the first embodiment, the undercut processing mechanism 11 of the second embodiment, and the molding dies 1 and 2 in that a metal such as iron, copper, or aluminum may be used.

  The undercut processing mechanism 15 is common in many parts to the undercut processing mechanism 10 of the first embodiment also in terms of configuration, but a drive for moving the holding piece forward and backward in conjunction with the closing and opening of the molding die. The means are different.

  The undercut processing mechanism 15 includes a holder 20 embedded and fixed in the movable mold plate 108, a sliding piece 30 having a forming part 32 for forming the undercut part P <b> 1 of the molded product P, and the sliding piece 30. And a holding piece 50 slidably held. Further, a cylinder 72 is provided as driving means for moving the holding piece 50 along the horizontal groove 24 of the holder 20. The configurations of the holder 20, the sliding piece 30, and the holding piece 50 are the same as those of the holder 20, the sliding piece 30, and the holding piece 50 of the undercut processing mechanism 10 of the first embodiment, and a description thereof will be omitted.

  The cylinder 72 is a cylinder including a cylinder tube 73 and a piston rod 74 connected to a piston housed in the cylinder tube 73, and is incorporated in the movable die 101 so that the holding piece 50 can advance and retreat. The distal end portion 75 of the piston rod is connected to the rear surface 55 of the holding piece 50, and the supply and discharge of the driving medium to and from the cylinder 72 causes the piston rod 74 to expand and contract, so that the holding piece 50 advances and retreats. The amount of expansion and contraction (stroke) of the piston rod 74 may be any as long as the holding piece 50 can be retracted so that the undercut can be removed, and a known reciprocating hydraulic cylinder or the like can be used as the cylinder 72.

  The operation of the molding die 3 according to the third embodiment of the present invention will be described. The undercut processing mechanism 15 operates in conjunction with the opening of the molding die 3 to remove the undercut, similarly to the undercut processing mechanism of the other embodiments. Specifically, the driving medium is supplied to and discharged from the cylinder 72 so that the piston rod 74 retreats in conjunction with the opening of the molding die 3. As a result, the holding piece 50 retreats along the horizontal groove 24 of the holder 20, and the sliding piece 30 moves along the oblique groove 22 of the holder 20 by the action of the dovetail groove 46 and the second ridge 54 of the holding piece 50. As a result, the molded portion 32 of the sliding piece 30 comes off the undercut portion P1 (see FIG. 16).

  When the mold 3 is closed, the undercut mechanism 15 is driven relative to the cylinder 72 so that the piston rod 74 moves forward (projects) in conjunction with the closing of the mold 3. The medium is supplied and ejected. As a result, the holding piece 50 moves forward (moves to the left in FIG. 16) along the horizontal groove 24 of the holder 20, and accordingly, the sliding piece 30 acts on the dovetail groove 46 and the second convex strip 54 of the holding piece 50. As a result, the sliding piece 30 moves along the oblique groove 22, and the upper surface 40 of the molded portion 32 of the sliding piece 30 is flush with the upper surface of the movable mold plate 108.

  In the molding die 3 of the third embodiment, the cylinder 72 is used as a driving means for moving the holding piece 50 of the undercut processing mechanism 15 forward and backward, but an electromagnet is used instead of the cylinder 72 to move the holding piece 50 forward and backward. You may do so. Further, the cylinder 72 and the electromagnet may be used in combination.

  The advance and retreat of the holding piece 50 using the electromagnet is not particularly limited, but can be performed, for example, in the following manner. A magnet is attached to the rear surface 55 of the holding piece 50, and the electromagnet is placed on a stopper 90 located at a position where the holding piece 50 is retracted. The polarity is switched by switching the direction of energization to the electromagnet, the holding piece 50 is retracted by attracting the magnet and the electromagnet, and conversely, the holding piece 50 is advanced by repelling the magnet and the electromagnet. The timing of energizing the electromagnet and switching of the energizing direction are performed in conjunction with the opening and closing of the molding die 3 as in the case of the cylinder 72. The magnet and the electromagnet may be arranged on the front side of the holding piece 50.

  As described above, according to the molding die 3 and the undercut processing mechanism 15 of the third embodiment, the holding piece 50 slides with respect to the holder 20 in conjunction with the opening of the molding die 3. Since the sliding piece 30 slides with respect to the holder 20 and moves so as to be disengaged from the undercut portion P1, the undercut portion P1 can be easily cut out while being compact and simple.

  Further, according to the undercut processing mechanism 15 of the third embodiment, the sliding piece 30 and the holding piece 50 can be assembled into the molding die 3 in a state of being partially accommodated in the holder 20, so that the compact structure is achieved. It is possible and easy to attach to the molding die 3. Further, for example, it is also possible to configure so that the sliding piece 30 and the holding piece 50 are completely stored in the holder 20 at the time of mold clamping.

  In the undercut processing mechanism 15 of the third embodiment, a large driving force can be obtained because the cylinder 72 is used for driving the holding piece 50. In the undercut mechanism 15 of the third embodiment, if an electromagnet is used instead of the cylinder 72, the undercut mechanism 15 can be made more compact.

  In the undercut processing mechanism 15 of the third embodiment described above, the cylinder 72, which is a driving means for moving the holding piece 50 forward and backward, operates in conjunction with the mold opening and the mold clamping. The cylinder 72 and the electromagnet employed in the cut processing mechanism 15 can basically operate independently. Therefore, the holding piece 50 can be moved forward and backward by an arbitrary stroke amount at an arbitrary timing during and after the mold opening.

  As described above, the undercut processing mechanism, the molding die, and the molded product of the present invention have been described using the molding dies 1, 2, and 3 of the first to third embodiments. The molding die and the molded product are not limited to the above embodiment, and can be used in a modified form without changing the gist. For example, the restricting means between the holder 20 and the sliding pieces 30 and 31 may be dovetail grooves and ridges. In this case, the holder 20 has dovetail grooves and the sliding pieces 30 and 31 have ridges. Alternatively, the holder 20 may be provided with a ridge, and the slide pieces 30, 31 may be provided with dovetail grooves. The same applies to the means for regulating the holder 20 and the holding pieces 50 and 51. Similarly, the regulating means between the sliding pieces 30 and 31 and the holding pieces 50 and 51 may be provided with ridges on the sliding pieces 30 and 31 and dovetail grooves on the holding pieces 50 and 51.

  Further, in the undercut processing mechanism of the present invention, the oblique groove 22 and the convex ridge 44, the horizontal groove 24 and the first convex ridge 52, and the dovetail groove 46 and the second convex ridge 54, which are fitted or engaged with each other, are formed by a fitting portion. Alternatively, the cross-sectional shape of the engaging portion is not limited to the rectangular shape shown in the drawing, and the fitting portion or the cross-sectional shape of the engaging portion may be circular, triangular, or the like. Further, in the undercut processing mechanism of the present invention, the respective restricting means of the holder 20, the sliding pieces 30, 31 and the holding pieces 50, 51 are not limited to those in the above-described embodiment. May be used.

  In the molding die 2 of the second embodiment, a compression coil spring is used as the spring 70 and is arranged on the front side of the holding piece 51. However, a tension spring may be used as the spring 70. When a tension spring is used as the spring 70, an accommodation hole for accommodating the spring 70 is provided on the rear surface side of the holding piece 51, and the spring 70 is disposed so as to bridge the bottom of the accommodation hole and the stopper 90. Good.

  The molding die 2 of the second embodiment uses a spring 70 as a driving means (first pressing means) for slidingly moving the holding piece 51, but instead of the spring 70, a hydraulic cylinder or an electromagnet which operates only in one direction May be used. Such a driving means such as a hydraulic cylinder or an electromagnet that operates only in one direction may be arranged not only on the front side of the holding piece 51 but also on the rear side.

  Further, the molded product that can be molded in the molding die of the present invention is not limited to a molded product whose undercut portion is a cylindrical boss. FIGS. 17A and 17B are perspective views showing an example of a molded product that can be molded by the undercut processing mechanism and the molding die of the present invention. The undercut processing mechanism of the molding die according to the present invention is particularly suitable for the direction of die removal of the molded product P as in the undercut portions P1, P2, and P3 shown in the first to third embodiments and FIG. It has a hollow or space formed by a molding member such as a pin 34, which cannot be removed with a conventional loose core that moves in a direction perpendicular to and crosses, and an undercut portion projects in a longitudinal sectional view. The present invention can be suitably used for forming and cutting an undercut portion having a plurality of protrusions arranged in a direction parallel to a surface.

  Further, in the molding die of the present invention, it is possible to provide a plurality of undercut processing mechanisms. That is, according to the undercut processing mechanism and the molding die of the present invention, it is possible to mold and remove a molded article having an undercut portion such as a plurality of cylindrical bosses. When the direction of projection of each undercut portion, that is, the direction in which the die can be removed is different, in each undercut processing mechanism, the corresponding undercut portion can be die-cut so that the holder, the sliding piece, and the inclined groove of the holding piece can be removed. The horizontal groove, the dovetail groove, the ridge and the like, the restricting means such as the holding piece, the driving means of the holding piece and the inclination angle of the inclined hole of the holding piece, or the shape of the holding piece and the forced tension piece may be appropriately set.

  In the undercut processing mechanism and the molding die of the present invention, R and C chamfers may be applied to corners and side edges of each component.

  Further, the material of each component used in the undercut processing mechanism and the molding die of the present invention is not limited to a specific material, and is used for a known undercut processing mechanism and a known molding die. The same material as the material of the member may be appropriately used. However, it is preferable to use a material having good slidability or a material subjected to surface treatment having good slidability for the sliding surface of each component. Each sliding surface is not limited to a surface contact, but may be a line contact or a point contact.

  Further, the undercut processing mechanism of the present invention is applicable to a molding die that opens and closes horizontally, vertically, or in other directions.

  Further, the undercut treatment mechanism and the molding die of the present invention can be suitably used for a mold die such as a die casting die, a mold press molding die, and the like, in addition to the injection molding die.

  As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will easily see various changes and modifications within the obvious scope in view of the present specification. Accordingly, such changes and modifications are to be construed as being within the scope of the invention as defined by the appended claims.

1, 2, 3 Molding molds 10, 11, 15 Undercut treatment mechanism 12 Angular pin 20 Holder 22 Slanting groove 24 Horizontal groove 30, 31 Sliding piece 32 Molding part 33 Front surface 34 Pin 35 Rear surface 36 Sliding part 44 Convex Line 46 Dovetail groove 50, 51 Holding piece 52 First convex part 54 Second convex part 59, 60 Inclined surface 61 Receiving hole 65 Fitting groove 66 Projection 70 Spring 72 Cylinder 80 Forced tension piece 81 Inclined surface 82 Claw P Molded product P1 , P2, P3 Undercut

Claims (12)

An undercut processing mechanism that is used by being attached to a molding die for molding a molded product having an undercut portion, and that allows the undercut portion protruding in a direction intersecting with the direction of demolding the molded product to be die-cuttable. So,
A holder fixed or integrally formed with the molding die,
A sliding piece that has a forming part for forming the undercut part, and is slidable with respect to the holder so that the forming part is separated from the undercut part.
A holding piece that slidably holds the sliding piece, which is capable of moving forward and backward in a direction intersecting with the direction of removing the molded product from the holder,
Driving means for moving the holding piece forward and backward,
With
The sliding piece is configured to move so that the forming part is disengaged from the undercut part by moving the holding piece via the driving means in conjunction with opening of the molding die. An undercut processing mechanism. The driving means is an inclined member attached to the molding die so as to be inclined with respect to the mold opening and mold clamping directions of the molding die,
The inclined member is engaged with the holding piece without engaging with the holder,
The undercut processing mechanism according to claim 1, wherein the holding piece moves forward and backward through the inclined member in conjunction with opening and closing of the molding die. The driving means is a cylinder and / or an electromagnet connected to the holding piece,
The undercut processing mechanism according to claim 1, wherein the holding piece can move forward and backward through the cylinder and / or the electromagnet. The driving unit includes a first pressing unit and a second pressing unit,
When the mold is opened, the holding piece moves by the action of the first pressing means,
2. The undercut processing mechanism according to claim 1, wherein the holding piece moves in a direction opposite to the direction when the mold is opened by the action of the second pressing means when the molding die is clamped. The first pressing means is a spring,
The second pressing means has an inclined surface which is attached to the molding die and which is inclined with respect to a mold opening and a mold clamping direction of the molding die. The undercut processing mechanism according to claim 4, wherein the piece is a piece that is slidably engaged with the undercut. The second pressing means is a forcible pulling piece having a claw on the bottom that engages with the holding piece,
The holding piece has a fitting groove into which the claw is fitted when the molding die is clamped,
6. The undercut process according to claim 5, wherein the forcible tension piece forcibly moves the holding piece at the time of opening the molding die through a claw engaging with the fitting groove. mechanism.   The undercut processing mechanism according to any one of claims 1 to 6, wherein the shaping portion has a tapered outer shape with a tip end portion narrower than a base end portion.   The holder and the holding piece each include a regulating unit that regulates a moving direction of the sliding piece when the mold for molding is opened in a direction in which the molding part comes off from the undercut part. Item 8. The undercut processing mechanism according to any one of items 1 to 7.   The undercut processing mechanism according to any one of claims 1 to 8, wherein the holder can partially or completely accommodate the sliding piece and / or the holding piece.   The slide piece is provided with a molding member for molding a hollow portion or a space portion of the undercut portion so that the molded product having a hollow portion or a space portion in the undercut portion can be formed. Item 10. The undercut processing mechanism according to any one of Items 1 to 9.   A molding die comprising the undercut processing mechanism according to any one of claims 1 to 10.   A molded article molded by the undercut treatment mechanism according to any one of claims 1 to 10, or a molding die according to claim 11.

Images