JP3225474U - Mold for injection molding of resin molded products - Google Patents

Abstract

The present invention provides a mold using a rotary slide that can mold a resin part having a shape with a nose protruding from a side wall that stands around a top surface by injection molding in one step. A mold includes a fixed mold plate, a movable mold plate facing the fixed mold plate, a nose bridge of a nose as a parting line, and an upper surface of the movable mold plate as a slide surface. 13 (a divided SA slide 13A, a divided SB slide 13B), an inner core 15 having a protruding core 151 nested in the movable mold plate 12, and protruding from the upper surface of the movable mold plate 12, and an inner core 15 inside the inner core 15. It has a rotary slide 16 provided with a head core 160 that moves back and forth on the provided core slideway 17. The rotary slide 16 of the mold is held by the movable mold plate 12, and the head of the head core 160 moves back and forth between the inside of the side wall and the nostril forming portion related to the formation of the nostril. The nose can be formed in one step. [Selection diagram] Fig. 1

Description

  The present invention relates to a mold for injection molding of a resin molded product having an undercut, and in particular, a mold for molding a resin molded product having a nose projecting outward from a closed peripheral wall portion by using a rotary slide. About the type.

  A slide die is used for molding a resin bumper or the like of an automobile having an undercut. However, in a mold using an angular pin and a slide core, the slide core is displaced or deformed due to the resin pressure, so that the surface of the resin product is likely to have a distortion or a change in thickness. In order to solve such a problem, a mold using a rotating slide has been proposed.

  Regarding the molding of a resin bumper for an automobile, for example, Patent Document 1 discloses a slide core which forms a part of a molding die surface when a mold is closed, forms an undercut portion, and moves in a direction away from the undercut portion when the mold is opened. Wherein the slide core is formed such that a sliding surface with the mold is curved, and the slide core is a rotating slide core that rotates along the sliding surface. Has been proposed.

  Patent Document 2 discloses a mold apparatus for resin-molding a molded article having a main body portion and an undercut portion, the mold body for molding the main body portion, and the undercut portion for molding the undercut portion. A rotating core that rotates and moves away from the part to release the mold, and during molding, sandwiches between the mold body and the rotating core to restrict the movement of the rotating core, and the undercut portion of the rotating core. At the time of release from the mold, there has been proposed a mold apparatus comprising: a regulating core that moves in a direction to come out of between the mold body and the rotating core to release the regulation of the rotating core.

  Patent Document 3 proposes a mold for molding a molded product having an undercut and a curved arc shape inside. That is, a curved core pin curved in an arc shape, a support pin for transmitting power to the curved core pin, a fixed guide core for guiding the support pin, a slide core for sliding the support pin, and a power source for the slide core The curved core pin is provided with the support pin, the fixed guide core is provided with a first curved sliding surface for guiding the support pin, and the second curved slide for transmitting sliding power to the support pin. By providing a surface on the slide core, disposing the support pins so as to slide on both the first curved sliding surface and the second curved sliding surface, and reciprocating the slide core. An arc slide structure of a molding die has been proposed in which the curved core pin enters and exits a cavity forming a molded product in an arc shape. This arc slide structure does not rotate the core for forming the arc shape about the rotation axis, so that a compact mold can be configured.

JP-A-6-114893 JP 2016-120612 A JP 2009-160885 A

  As shown in Patent Literatures 1 to 3, a mold using a rotary slide core, a rotary core or an arc slide core (rotary slide) for molding a resin molded product having an undercut is compact, and has a surface with distortion and wall thickness. It is possible to mold a resin molded product having a small change in thickness. On the other hand, resin molded products have various shapes, and the forms of undercuts they have also vary. For this reason, a slide mold suitable for molding each resin molded article is used, and a mold using a rotary slide is used.

  However, it is preferable to deform the required resin molded product to an acceptable degree and design a mold utilizing the characteristics of the rotary slide as an efficient molding method of the resin molded product. For example, the jug-shaped resin part 1 shown in FIG. 5 has a shape in which a nose part 4 protrudes from a side wall part 2 standing upright surrounding a top surface part 3. Such a resin component is formed in two steps, such as first forming a rough member having no top surface portion 3 and then bonding or welding the top surface portion 3 to the formed rough member. It is preferable if such a resin part can be molded in one step.

  The present invention uses a rotating slide that can mold a resin part having a shape with a nose protruding from a side wall that stands around a top surface part by an injection molding without a bonding or welding step. The purpose is to provide a mold.

  The mold according to the present invention is a mold for injection molding for molding a resin molded product, wherein the resin molded product has a top surface portion, a side wall portion erected around the top surface portion, and a side wall portion thereof. A nose protruding outward from the nose, and a bottom surface having an opening, the nose having a circular cross section, and a nose bridge of the nose intersects the side wall in the XY cross section. The upper end of the root of the nose, and an arc-shaped curve convex upward from the lower end of the root of the nose opposite thereto, the upper end of the root of the nose is point p1, the lower end is point p2, and the center of curvature of the bridge of the nose is the center C0. , The radius of curvature ρ1 (point p1-the length of the center C0), the radius of curvature ρ2 (point p2-the length of the center C0), the outer circle (center C0, the radius ρ1), the inner circle (center C0, the radius ρ2) ), The outer peripheral circle is provided so as to pass through the opening to the outside, the nose bridge is on the outer peripheral circle, and the nose is inside the outer peripheral circle. The mold is in a circular tube including a peripheral circle, and the mold is a fixed mold plate, a movable mold plate opposed thereto, and a nose bridge of the nose as a parting line, and slides on the upper surface of the movable mold plate. A surface slide (split SA slide, split SB slide), an inner core having a protruding core nested in the movable mold plate and projecting from the upper surface of the movable mold plate, and the nose formed by the slide. A rotating slide held by the movable mold plate, comprising a head core that moves in and out of the protruding core into and out of the nostril portion of the part and moves along a core sliding path in the inner core provided along the outer circumferential circle. In the cavity for molding the resin molded product, a bottom portion is formed by the fixed side mold plate and the inner core, a side wall portion is formed by the slide and the inner core, and a nose portion is formed by the slide and the rotary slide. Thus, it is formed. Here, in the rectangular coordinate system XYZ, a plane including the bridge of the nose, the upper end p1 of the nose root, and the lower end p2 of the nose root is defined as an XY plane.

  In the above invention, the head core of the rotary slide may be rotated by the driving means via the link.

  Further, the inner core in which the core sliding path is formed is preferably composed of a divided inner core CA and a divided inner core CB having an XY cross section as a parting surface, and is preferably provided with a space in which the link swings.

  Further, in the head core, the thickness (point p1-point p2) of the nose root portion of the nostril forming portion can be set to 0.8 or less of the inner inscribed circle radius of the side wall portion.

  Further, the mold according to the present invention is a resin having a top surface portion, a side wall portion standing upright surrounding the top surface portion, a nose portion projecting outward from the side wall portion, and a bottom portion having an opening. A mold for molding a nostril of the nose of a molded article, wherein a nose bridge of the nose is formed by a part of an upwardly projecting arc (outer circumference circle) which escapes from the opening in the XY cross section, A head that enters and exits the nostril forming portion where the nostril of the nose is formed from the internal space inside the side wall portion, and a support portion that supports the head and holds the head at a predetermined position is provided along the outer circumferential circle. A rotary slide having a head core that advances and retreats a provided core slide path, an inner core that forms the internal space and is provided with the core slide path, and a movable mold plate that holds the inner core and the rotary slide And Here, the XYZ coordinate system is a rectangular coordinate system in which the plane including the bridge of the nose, the point p1 at the upper end of the nose, and the point p2 at the lower end of the nose is an XY plane.

  In the above invention, it is preferable that the support portion of the head core has a function of preventing a rotation of the head core by a joint portion serving as a connection portion with a driving means for driving the head core.

  In the mold according to the present invention, a resin part having a shape in which a nose protrudes from a side wall that stands upright surrounding a top surface can be formed by injection molding at one time. Further, it is possible to mold a resin molded product having little distortion or a change in thickness on the surface.

FIG. 3 is a cross-sectional view of the injection mold according to the present invention. It is explanatory drawing which shows the cross section of the resin molded product shape | molded by the metal mold | die shown in FIG. It is explanatory drawing of the rotating slide part of the metal mold | die shown in FIG. It is explanatory drawing of the core advance / retreat part of the metal mold | die shown in FIG. FIG. 4 is an illustration of another embodiment of a nose portion that can be formed according to the present invention. It is explanatory drawing of the conventional resin molded article and its molding method.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a configuration of an injection molding die according to the present invention. The injection molding die is used for molding a resin molded product 1 having a nose 4 shown in FIG. The mold 10 has a fixed mold plate 11, a movable mold plate 12 facing the fixed mold plate 11, and a nose bridge 4a of the nose portion 4 as a parting line, and a slide 13 having an upper surface of the movable mold plate 12 as a slide surface. (Split SA slide 13A, split SB slide 13B), an inner core 15 having a projecting core 151 nested in the movable mold plate 12 and projecting from the upper surface of the movable mold plate 12, and provided inside the inner core 15. And a rotating slide 16 provided with a head core 160 that advances and retreats through the provided core sliding path 17. The rotating slide 16 is held by the movable mold plate 12.

  As shown in FIG. 2, the resin molded product 1 has a top surface portion 3, a side wall portion 2 standing upright surrounding the top surface portion 3, a nose portion 4 protruding outward from the side wall portion 2, and an opening portion. And a bottom portion 5 having 5a. Although the top surface portion 3 in this example is closed with a plate-shaped resin, it may be open.

  In the mold 10 according to the present invention, the nostril portion of the nose portion 4 to be undercut is formed using the rotating slide 16. For this reason, the nose bridge 4a of the nose part 4 is formed into an arc shape within the allowable range in design so that the head core 160 of the rotary slide 16 used for forming the nostril part comes out of the opening part 5a of the bottom part 5. In other words, at the nose portion where the nose portion 4 protrudes from the side wall portion 2, the nose portion 4 extends from the upper end of the nose root portion where the nose bridge of the nose portion 4 intersects the side wall portion 2 in the XY cross section, and from the lower end of the nose root portion opposed thereto. It is formed from an upwardly convex arc-shaped curve. Here, the upper end of the nose root is point p1, the lower end is point p2, and the XYZ coordinate system is a rectangular coordinate system in which a plane including the nose bridge 4a, points p1 and p2 is an XY plane. Then, the center of curvature of the nose bridge 4a is the center C0, the radius of curvature is ρ1 (the length of the point p1-the center C0), the radius of curvature is ρ2 (the length of the point p2-the center C0), and the outer circumference circle (the center C0, the radius ρ1) , The inner circumference circle (center C0, radius ρ2). At this time, the nose bridge 4a is on the outer circumference circle, and the nose 4 is in a circular tube including the outer circumference circle and the inner circumference circle.

  As shown in FIG. 2, the nose bridge 4a is on the outer circle 7, and the nose 4 is housed in a circular tube including the outer circle 7 and the inner circle 8. The mold according to the present invention is configured to satisfy the above requirements. That is, the bridge of the nose 4a is on the outer circumference circle passing through the opening 5a of the bottom surface 5, the nose 4 is formed of an arc passing through the point p1 at the upper end of the nose root, and the point p2 at the lower end of the nose root, and the nose 4 is the outer circumference circle. A mold using a rotating slide is configured so as to be housed in a circular tube including the inner circle 7 and the inner circle 8. In the case of this example, the valley line 4b of the nose portion 4 passing through the point p2 and facing the nose bridge 4a has a radius of curvature ρ2, but the center of curvature is different from the center C0. The cross section of the nose 4 is a tapered circular shape. With such a configuration of the nose 4, the nostrils of the nose 4 can be formed without undercuts. Then, as shown by the broken line in FIG. 2, by retracting the head core 160 of the rotary slide 16 to the inside of the side wall portion 2, it is possible to form the undercut nose in one step.

  The cavity of the resin molded product 1 is formed in the mold 10 as follows. That is, the bottom part 3 is formed by the fixed side template 1 and the inner core 15, the side wall part 2 is formed by the slide 13 and the inner core 15 formed of the divided A slide 13A and the divided B slide 13B, and the nose part 4 is formed by the slide 13 and the rotary slide. , Is formed.

  The rotating slide portion of the mold 10 will be described. FIG. 3 is an explanatory view of a rotary slide, and FIG. 4 is an explanatory view of a core slideway on which a head core of the rotary slide slides. The head core 160 of the rotating slide 16 advances and retreats on a core sliding path 17 provided inside the inner core 15. The core slideway 17 opens from the inside of the protruding core 151 of the inner core 15 to a nostril forming portion 18 formed by the slide 13 related to the formation of the outer shape of the nose 4. The rotary slide 16 has a head core 160, a link 164, and a driving unit 165. The driving means 165 may use a hydraulic or pneumatic cylinder, or an angular pin & slide. The link 164 connects the head core 160 and the driving unit 165, and allows the driving unit 165 to smoothly advance and retreat the head core 160.

  The head core 160 has a head portion 161 that enters and exits the nostril forming portion 18 from the core sliding path 17 and a support portion 162 that slides on the core sliding path 17 to advance and retreat. By setting the outer shapes of the support portion 162 and the core slideway 17 to have a predetermined hook-eye size, the head portion 161 can be held at a predetermined position of the nostril forming portion 18. However, the head 161 may rotate around its axis. For this reason, it is preferable to provide a function of preventing the rotation of the head core at a joint portion serving as a connection portion of the head core 160 with the driving means. For example, as shown in a DD section of FIG. 3, a joint 162a having a square section can be provided. Accordingly, the head core 160 can smoothly slide on the core sliding path 17 without rotating around the axis. As a structure for preventing the rotation of the head core 160 around the axis, a groove may be provided in the core slideway 17 so that the joint having the protruding rib advances and retreats along the groove.

  As shown in FIG. 4, the core slide path 17 is provided along the outer circumference circle 7 and the inner circumference circle 8, and is provided so that the head 161 of the head core 160 opens to the nostril forming part 18 where the head core 160 advances and retreats. A joint slideway 17a is provided in the core slideway 17 on which the support portion 162 slides so that the head core 160 having the joint 162a can move forward and backward stably and smoothly. In order to provide the core sliding path 17 in the inner core 15, it is preferable that the inner core 15 be a two-split type of a split inner core CA and a split inner core CB whose XY cross section is a parting surface. This facilitates processing of the core slideway 17 and disposition of the rotary slide 16. In addition, a required space can be easily provided in the inner core 15 because the link 164 swings.

  The mold according to the present invention has been described above. The mold according to the present invention can be applied not only to the molding of a resin molded product having a circular nose having a tapered cross section as in the above-described mold. The cross section of the nose may have a constant shape in the longitudinal direction, or may have a shape other than a circular diameter. For example, as shown in FIG. 5, the cross section of the nose 4 has a rectangular cross section with a width b, the upper edge of the nose 4 over the width b is formed by the same arc as the nose bridge 4a, and the nose bridge 4a has a side wall. The resin molded product on the circular arc (outer peripheral line 7) passing through the opening 5a of the second part and the valley line 4b of the nose part 4 is circular can be molded by the mold according to the present invention.

  On the other hand, when the bridge of nose 4a is on the outer peripheral line 71 in FIG. 5, the outer peripheral line 71 is blocked by the side wall portion 2 and cannot pass through the opening 5a to the outside. However, when the entire nose portion 4 is large enough to be accommodated in the inner space inside the side wall portion, the head core 161 forming the nostrils of the nose portion 4 is supported by the head 161 and the head core 161 which supports the head core 161 and holds it at a predetermined position. The resin molded product having the nose portion 4 can be formed by the mold according to the present invention if the support portion 162 is constituted by the portion 162 and the support portion 162 can be pulled out along the outer circumferential circle 7. According to the mold according to the present invention, a resin molded product having a nose portion having a thickness (point p1-point p2) of the nose root portion of the nostril formation portion of 0.8 or less of the inner inscribed circle radius of the side wall portion is formed. be able to.

  The mold according to the present invention can efficiently form an undercut portion using a rotary slide, such as a resin molded product having a nose protruding from a closed side wall. Such a resin molded product is not limited to a product such as a jug or a watering can shown in FIG. 1, but may be a part for horticulture, general industry, or automobile.

1 Resin molding
2 Bottom part
3 Side wall
4 Nose
5 Top panel
5a opening
7, 71 Arc including nose bridge
10 Mold
11 Fixed side template
12 Movable mold plate
13 slides
131 split A slide
132 split B slide
15 Inner core
151 protruding core
16 rotating slides
160 head core
161 head
162 Support
162a Joint
164 links
165 drive
17 Core slideway
17a Joint slideway
18 Nostril formation

Claims (6)

A mold for injection molding for molding a resin molded product,
The resin molded product has a top surface portion, a side wall portion standing upright surrounding the top surface portion, a nose portion protruding outward from the side wall portion, and a bottom portion having an opening,
The nose has a circular cross-section, and in the XY cross-section, an arc-shaped convex upward from the upper end of the nose root where the nose bridge intersects with the side wall and the lower end of the nose root facing the nose. Formed from the curve of
The upper end of the root of the nose is point p1, the lower end is point p2, the center of curvature of the bridge of the nose is center C0, the radius of curvature is ρ1 (the length of point p1-center C0), and the radius of curvature is ρ2 (point p2-center C0). Length), outer circle (center C0, radius ρ1), inner circle (center C0, radius ρ2)
The outer peripheral circle is provided so as to escape from the opening, the nose bridge is on the outer peripheral circle, and the nose is in a circular tube including the outer peripheral circle and the inner peripheral circle,
The mold includes a fixed mold plate, a movable mold plate facing the fixed mold plate, and a nose bridge of the nose as a parting line, and a slide having a top surface of the movable mold plate as a slide surface (divided SA slide, A split SB slide), an inner core having a protruding core nested in the movable mold plate and protruding from the upper surface of the movable mold plate, and the protruding core formed in the nostril portion of the nose formed by the slide. Rotating slide held on the movable mold plate, comprising a head core that moves in and out, and advances and retreats a core sliding path in the inner core provided along the outer circumferential circle,
A mold having a cavity for molding the resin molded article, wherein a bottom surface is formed by the fixed mold plate and the inner core, a side wall is formed by the slide and the inner core, and a nose is formed by the slide and the rotary slide.
Here, the XYZ coordinate system is a rectangular coordinate system in which the plane including the bridge of the nose, the points p1 and p2 is the XY plane.   The mold according to claim 1, wherein the head core of the rotary slide is rotated by a driving unit via a link.   The inner core on which the core sliding path is formed is composed of a divided inner core CA and a divided inner core CB having an XY cross section as a parting surface, and a space for swinging the link is provided. Item 3. The mold according to Item 2.   The mold according to claim 1 or 2, wherein the head core has a thickness (point p1-point p2) of a nose root portion of the nostril forming portion which is 0.8 or less of an inner inscribed circle radius of the side wall portion. Forming the nostrils of the nose of a resin molded product having a top surface, a side wall standing upright surrounding the top surface, a nose protruding outward from the side wall, and a bottom having an opening. Mold
The nasal bridge of the nose is formed by a part of an upwardly projecting circular arc (circumferential circle) that goes out of the opening in the XY cross section, and the nasal cavity forming part where the nares of the nose are formed has the side wall part inside. A head sliding in and out of the internal space, a supporting portion for supporting the head and holding the head at a predetermined position, and a rotary slide having a head core that advances and retreats along a core sliding path provided along the outer circumferential circle; A mold comprising: an inner core that forms the internal space and is provided with the core sliding path; and a movable mold plate that holds the inner core and the rotary slide.
Here, the XYZ coordinate system is a rectangular coordinate system in which the plane including the bridge of the nose, the point p1 at the upper end of the nose, and the point p2 at the lower end of the nose is an XY plane.   6. The mold according to claim 5, wherein the support portion of the head core has a function of preventing a rotation of the head core by a joint portion serving as a connection portion with driving means for driving the head core.

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