JP2014124931A - Injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding device capable, while attempting unprecedented miniaturization, of assuredly releasing a molding from molds.SOLUTION: An injection molding device 10 of the present invention comprises: a fixed mold 11; a mobile mold 12; an injection unit 20 for injecting and feeding, on a mold fastening occasion, a molten resin in-between the fixed mold 11 and mobile mold 12; and an extrusion mechanism 40 for extruding, along the mold releasing direction, a molding molded as a result of the solidification of the molten resin injected and fed by the injection unit 20. The fixed mold 11 and mobile mold 12 are respectively a core and a cavity. The extrusion mechanism 40 is configured on the side of the core. The extrusion mechanism 40 possesses a plurality of elastic support units 42 elastically supported on the fixed mold 11. The elastic support units 42 can be mobilized, when pressed into the cavity on the mold fastening occasion, to a position where the core-side edge surface of the molding can be molded.

Description

  The present invention relates to an injection molding apparatus, and more particularly to an injection molding apparatus suitable for releasing large resin parts such as automobile bumpers.

    In general, a bumper for an automobile is integrally molded as a resin part by injection molding from the viewpoint of manufacturing cost and design flexibility. This type of molded product is very large, and has a very complicated three-dimensional shape from the viewpoint of safety and design. For this reason, usually, this type of injection molding apparatus is often provided with an extrusion pin for the purpose of reliably releasing the molded product from the molding die (see, for example, Patent Document 1). In this case, the movable mold is a core, the fixed mold is a cavity, an extrusion mechanism having an extrusion pin on the core side, and an injection unit having an injection nozzle on the cavity side are generally provided (for example, (See FIG. 4 of Patent Document 1 and paragraph 0027).

JP-A-9-201841

  As described above, in the molding die used in this type of molding apparatus, the extrusion mechanism and the injection unit are generally arranged in separate molds, but the injection unit and the extrusion mechanism are separately provided. When it is arranged in the mold, it is natural that the injection molding apparatus itself becomes very large, resulting in an increase in the occupied space. This results in a contradiction to the space saving of facilities that have been increasingly demanded in recent years, and therefore it is necessary to urgently take measures to reduce the size of the injection molding apparatus.

  Here, for example, it is conceivable that the extrusion mechanism that has been conventionally provided on the movable mold side is provided on the same mold as the injection unit, that is, on the fixed mold side. However, in this type of mold, in addition to the injection unit and the extrusion mechanism, a large number of various inevitable components including a cooling system are arranged. There is also a limit to the space in which can be installed. In addition, the larger the parts to be injection-molded, such as automobile bumpers, the larger the amount of molten resin that is required, and the larger the injection unit itself must be. As for the extrusion mechanism, when the injection molded product to be extruded is a large product such as a bumper for automobiles, a plurality of extrusion pins are required to extrude the molded product at a plurality of locations. The extrusion mechanism is inevitably enlarged. Therefore, with the current configuration, it is difficult to provide the extrusion mechanism and the injection unit in the same mold.

  In view of the above circumstances, the problem to be solved by the present invention is to provide an injection molding apparatus capable of reliably releasing a molded product from a mold while achieving downsizing as compared with the prior art.

  The solution to the above problem is achieved by the injection molding apparatus according to the present invention. That is, this molding apparatus is formed by solidifying a fixed mold, a movable mold, an injection unit for injecting and supplying molten resin between the fixed mold and the movable mold at the time of mold clamping, and a molten resin injected and supplied by the injection unit. In the injection molding apparatus provided with an extrusion mechanism for extruding the molded product in the mold release direction, the fixed mold is a core, the movable mold is a cavity, and the extrusion mechanism is disposed on the core side. It has a plurality of elastic support portions that are elastically supported by the fixed mold, and the elastic support portions can be moved to a position where the end surface on the core side of the molded product can be molded by being pushed into the cavity during mold clamping. Characterized with points.

  As described above, in the present invention, the extrusion mechanism is disposed on the core side with the fixed mold as the core, and the extrusion mechanism is configured by a plurality of elastic support portions that perform a predetermined operation in accordance with the mold clamping operation. And That is, the plurality of elastic support portions constituting the extrusion mechanism are pushed into the cavity during mold clamping, and the end surface of the molded product is formed by the elastic support portion by moving the end surface of the molded product to a position where it can be molded. Is done. When injection molding is completed and mold opening is started, the cavity that becomes the movable mold moves away from the core that is the fixed mold, so that the elastic support portion that has been pushed into the cavity is Try to return to the position before being pushed. Here, since the elastic support portion is molding the end surface of the molded product on the core side, the end surface of the molded product is pressed in the mold release direction by the elastic restoring force of the elastic support portion. With the above operation, the end face of the molded product is extruded in the mold release direction at a plurality of locations, thereby eliminating the contact state between the molded product and the core. Therefore, the molded product can be easily and reliably removed from the mold after the mold opening is completed. In this case, the end face can be molded with the clamping force, and with the elastic restoring force stored at the time of clamping, the pressing force can be applied to the molded product so that the adhesion between the molded product and the core can be eliminated. Compared with the conventional extrusion mechanism in which each individual extrusion pin needs to be driven by a driving means separate from the mold, it is possible to achieve a significant reduction in size. Moreover, since it is not necessary to penetrate the whole metal mold | die like an extrusion pin, the rigidity fall of a metal mold | die can also be prevented.

  Further, in the injection molding apparatus according to the present invention, at least a part of the plurality of elastic support portions is placed at a position where the end surface on the core side of the opening formed in the molded product can be molded by being pushed by the cavity during mold clamping. It may be arranged.

  Some large resin parts such as automobile bumpers are provided with openings such as grills and lamp mounting holes, for example. A cavity is provided on the inner periphery of the opening, and the opening In general, a mating surface (parting surface) between the cavity and the core is located on the same plane as the end surface on the core side. Therefore, paying attention to this opening, at least a part of the plurality of elastic support parts is disposed at a position where the core side end face of the opening formed in the molded product can be molded by being pushed by the cavity during mold clamping. did. As a result, at the time of mold clamping, the corresponding elastic support part is pushed in at the part constituting the inner periphery of the opening part of the cavity, so that the end surface on the core side formed around the opening part is molded by the elastic support part. can do. Further, the end surface on the core side is pressed in the mold release direction by the force with which the elastic support portion returns to the position before being pushed by the cavity along with the mold opening operation after the molding is completed. As a result, not only the edge of the molded product but also the central region can be extruded in the mold release direction by the extrusion mechanism, so that even large resin parts such as automobile bumpers can be reliably released. be able to.

  An injection molding apparatus according to the present invention is provided in a movable mold, which is engaged with an undercut portion formed at an edge of a molded product and is slidable in a direction intersecting the mold opening direction. Further, a guide unit that guides a sliding operation in a direction in which the undercut portion of the slide member is expanded in accordance with the mold opening operation may be provided.

  Thus, when an undercut part exists in a molded product, in the mold release operation | movement only of the above-mentioned extrusion mechanism, since an undercut part is forcibly extracted, the quality control of a molded product becomes difficult. Here, by providing the slide member and the guide portion configured as described above, the undercut portion is peeled off from the core when the mold is opened. Therefore, in conjunction with the extrusion operation of the molded product by the extrusion mechanism, the undercut portion is expanded with a slide member to the extent that it does not interfere with the core, so that the molded product having the undercut portion can be safely separated without forcibly removing it. Can be typed. In particular, since the undercut portion is provided at the edge of the molded product, the molded product is gradually peeled from the core starting from the edge by expanding the undercut portion. As a result, air can be drawn between the core and the molded product, and release of the molded product can be promoted, and the molded product can be more easily released from the core by the extrusion operation by the elastic support portion. . Further, since this mechanism also uses the mold clamping force and the mold opening force for the sliding force, no separate driving means is required, and this also simplifies the apparatus.

  As described above, according to the present invention, it is possible to provide an injection molding apparatus capable of reliably releasing a molded product from a mold while achieving downsizing as compared with the prior art.

It is sectional drawing of the injection molding apparatus which concerns on one Embodiment of this invention. It is a front view of the injection molded product shape | molded with the injection molding apparatus shown in FIG. It is sectional drawing of the injection nozzle mechanism of the injection molding apparatus shown in FIG. It is the figure which looked at the gate block which comprises the injection nozzle mechanism shown in FIG. 3 from the nozzle side. It is sectional drawing of the injection nozzle mechanism shown in FIG. It is sectional drawing of the extrusion mechanism of the injection molding apparatus shown in FIG. It is sectional drawing of the forced mold release mechanism of the injection molding apparatus shown in FIG. It is sectional drawing of the pin drawing mechanism of the injection molding apparatus shown in FIG. It is sectional drawing of the extrusion mechanism at the time of a mold opening. It is sectional drawing of the forced demolding mechanism at the time of mold opening. It is sectional drawing of the pin pull-out mechanism at the time of a mold opening. It is sectional drawing of the pin pull-out mechanism at the time of a mold opening. It is sectional drawing of the injection molding apparatus which shows the state of the molded article at the time of mold opening. It is sectional drawing of the extrusion mechanism which concerns on other embodiment of this invention.

  Hereinafter, an injection molding apparatus according to an embodiment of the present invention will be described with reference to FIGS. Here, a case where an automobile bumper is injection molded by the above injection molding apparatus will be described as an example.

  FIG. 1 is a view showing an injection molding apparatus 10 according to an embodiment of the present invention. The injection molding apparatus 10 includes a fixed mold 11, a movable mold 12, an injection space 13 formed between the fixed mold 11 and the movable mold 12 when the mold is clamped, and an injection for supplying molten resin to the injection space 13. The unit 20, the gate block 30 disposed between the injection space 13 and the injection unit 20, the extrusion mechanism 40 for extruding the molded product 1 (see FIG. 2) in the mold release direction, and the under of the molded product 1 A forced demolding mechanism 50 for forcibly demolding the cut portion 2 (see FIG. 2) and a pin pulling mechanism 60 for pulling out the pin 61 from the hole 3 of the molded product 1 are provided.

  Here, the fixed mold 11 is a core, and the movable mold 12 is a cavity, and the injection unit 20, the gate block 30, and the pushing mechanism 40 are all arranged on the fixed mold 11 side. In the present embodiment, the forcible mold release mechanism 50 and the main part of the pin pull-out mechanism 60 are also arranged on the fixed mold 11 side.

  The injection unit 20 includes an injection machine 21, a hot runner 22 for supplying the molten resin injected from the injection machine 21 to the injection space 13, and a nozzle portion 23 provided integrally or separately at the tip of the hot runner 22. And a band heater 24 disposed around the hot runner 22 and a valve pin 25 for opening and closing the nozzle portion 23 by being inserted into or removed from the inner periphery of the nozzle portion 23.

  The gate block 30 defines a part of the injection space 13 and makes contact with the nozzle portion 23 of the injection unit 20 to constitute an injection gate mechanism. Specifically, as shown in FIG. 3, the gate block 30 has a nozzle contact surface 31 that can contact the nozzle portion 23 of the injection unit 20 and a nozzle contact surface 31 that is adjacent to the injection space 13. And a gate 32 to be operated. In the present embodiment, the gate 32 has a shape corresponding to the rib 4 (broken line in FIG. 2) erected on the back surface of the molded product 1, and is disposed at one or a plurality of locations adjacent to the injection space 13. Is done. Here, as shown in FIG. 2, the shape and arrangement of the gate 32 is such that the rib 4 is erected on the back surface 1b along the character line 1c formed on the front surface 1a of the molded product 1 serving as a design surface. The installation position is set.

  Further, when viewed in relation to the nozzle portion 23, the thickness dimension of the gate 32 is smaller than the opening diameter of the nozzle portion 23 and the longitudinal dimension thereof is the outer diameter of the nozzle portion 23 as shown in FIG. Bigger than. In other words, the rib-shaped gate 32 extends in the diameter direction of the nozzle portion 23 beyond the position of the outer peripheral surface of the nozzle portion 23. Further, as shown in FIG. 5, the gate 32 has a flat shape at the contact portion with the nozzle portion 23, and the standing height from the back surface of the rib 4 gradually decreases toward the both sides in the longitudinal direction. It has a shape.

  As shown in FIG. 6, the push-out mechanism 40 has a plurality of elastic support portions 42 that are elastically supported by the fixed mold 11 via elastic members 41 such as springs. The elastic support portion 42 has a mold contact surface 43 that contacts the movable mold 12 as a cavity, and a molding surface 44 that molds the end surface 1d of the molded product 1 (see FIG. 9). By being pushed into the movable mold 12, the end surface 1d of the molded product 1 can be moved to a position where it can be molded (position shown in FIG. 6). In this state, the elastic support portion 42 receives an urging force (elastic restoring force) in the mold opening direction from the elastic member 41 with respect to the mold opening direction. A guide surface 15 (for example, a tapered surface as shown in the figure) for guiding the outer surface of the elastic support portion 42 in the mold opening direction is formed in the accommodation hole 14 of the fixed mold 11 that accommodates the elastic support portion 42. At this time, the elastic support portion 42 can be moved in the mold opening direction while maintaining a contact state with the end surface 1d of the molded product 1. At this time, the rigidity (elastic coefficient) of the elastic member 41 is such that the elastic support portion 42 can move the end surface 1d to a position where the end surface 1d can be formed by pressing the cavity (movable mold 12) accompanying the mold clamping operation. The size is set to be smaller than the size, and the size is set to a size that can partially eliminate the close contact state of the molded product 1 with the fixed die 11 that is the core with the elastic restoring force stored at the time of clamping. Is preferred.

  In the present embodiment, at least a part of the plurality of elastic support portions 42 is such as the grill portion 5 or the lamp mounting hole 6 (FIG. 2) formed in the molded product 1 by being pushed by the movable die 12 at the time of clamping. The end surface 1d formed around the opening is disposed at a position where it can be molded. In this illustrated example, the shape and size are set so that one elastic support portion 42 (molding surface 44) can extrude the entire end face 1d of one opening. In addition, when arrange | positioning in the grill part 5, it is hard to release from other places (it is hard to peel off from the fixed mold | type 11). You may make it arrange | position the elastic support part 42 in the intersection part of the grating | lattice part in the grill part 5 so that extrusion is possible.

  As shown in FIG. 7, the forcible mold release mechanism 50 is folded inward at both ends of the undercut portion 2 formed at the edge of the molded product 1, here, the both ends of the bumper in the width direction (left-right direction in FIG. 2). The undercut portion 2 (FIG. 10) having a shape is forcibly expanded toward the outer side in the width direction so that the undercut portion 2 is removed. The forced mold release mechanism 50 is provided in the movable mold 12 that is engaged with the undercut portion 2 and is slidable in a direction intersecting the mold opening direction, and the slide member 51 is provided in accordance with the mold opening operation. And a guide portion 52 that guides a sliding operation in a direction in which the undercut portion 2 is expanded.

  In this embodiment, the slide member 51 includes a first connecting member 54 and a second connecting member 55 that are connected to each other via a connecting portion 53, and the undercut portion 2 is formed on the first connecting member 54. After the molding, an engaging portion 56 that engages with the undercut portion 2 in the sliding direction is formed. Moreover, the 1st connection member 54 is elastically supported by the fixed mold | type 11, and is receiving the urging | biasing force of the direction which expands the undercut part 2 after shaping | molding to the width direction outer side at the time of mold clamping. The guide portion 52 includes a protruding portion 57 that protrudes from the movable die 12 in a direction inclined with respect to the mold clamping direction, and a fitted portion 58 that is provided on the second connecting member 55 and into which the protruding portion 57 is fitted. Composed. Therefore, by moving the movable mold 12 in the mold clamping direction with the protruding portion 57 fitted to the fitted portion 58, the fitted portion 58 fitted to the protruding portion 57, and thus the fitted portion. The second connecting member 55 provided with 58 moves toward the inner side in the width direction, and the movable die 12 moves in the mold opening direction, so that the second connecting member 55 moves toward the outer side in the width direction. Yes. Further, when the forced mold release mechanism 50 adopts the structure shown in FIG. 8, the sliding amount of the second connecting member 55 is slightly absorbed by the connecting portion 53, so that the movable mold 12 is slightly opened from the molded product 1 in the mold opening direction. After the separation, the expanding operation of the undercut portion 2 toward the outer side in the width direction is started.

  Here, regarding the timing at which the undercut portion 2 is forcibly demolded by the forcible demolding mechanism 50 (pushing outward in the width direction to a predetermined amount), in the present embodiment, the molded product 1 body is fixed by the extrusion mechanism 40. 11 is set so as to start forced demolding of the undercut portion 2 in synchronism with the timing at which separation from 11 starts. Moreover, as the final stage, the time when the extrusion operation of the molded article 1 main body by the extrusion mechanism 40 is completed coincides with the time when the forced removal operation of the undercut portion 2 by the forced removal mechanism 50 is completed.

  The pin pulling mechanism 60 projects the molded product 1 in the injection space 13 and causes the molded product 1 to be pinned by projecting a pin 61 that can be moved into and out of the injection space 13 during mold clamping. This is a mechanism for forming the hole 3 corresponding to 61. More specifically, the pin pulling mechanism 60 is elastically supported by the fixed mold 11 and slides in the mold opening direction in accordance with the mold opening operation, and is elastically supported by the first slide section 62 and the first slide. Along with the sliding operation of the part 62 in the mold opening direction, the second slide part 63 that moves the pin 61 in the direction of pulling out from the hole 3 and the movable mold 12 are provided. And a regulating portion 64 that regulates the sliding operation in the mold opening direction. The pin 61 is provided at the tip (end on the injection space 13 side) of the second slide part 63. In this embodiment, the hole 3 of the collar part standing from the lower end part (lower side of FIG. 2) of the molded product 1 to the back surface 1b side (in the case of an automobile bumper, a hole for fixing the fender liner with a clip or the like). A pin pulling mechanism 60 is provided as a mechanism for pulling out a pin for forming the pin.

  In this embodiment, the restricting portion 64 is configured by an urging block that is elastically supported with respect to the movable mold 12 and is urged toward the mold clamping direction. As shown in FIG. Then, it comes into contact with the fixed mold 11 in the same plane as the movable mold 12. The contact surface may be a parting surface. Here, the urging force in the mold clamping direction of the urging block as the restricting portion 64 is set to be larger than the urging force in the mold opening direction received by the first slide portion 62 at the start of the mold opening operation. Thus, after the mold opening operation is started, the sliding operation of the first slide portion 62 in the mold opening direction can be restricted. Further, the accommodating portion 16 of each slide portion 62, 63 provided in the fixed mold 11 is in contact with the second slide portion 63 in the mold opening direction of the second slide portion 63 and the direction of pulling out from the hole 3. A guide surface 17 (tapered surface) for guiding the movement is formed. Thereby, the urging force of the restricting portion 64 decreases with the movement of the movable die 12 (mold opening operation), and from the point when the urging force of the first slide portion 62 becomes lower than the second slide portion 63, It is possible to slide on the guide surface 17.

  In this embodiment, after the time when the undercut part 2 of the molded product 1 is pushed and expanded to a position where it does not interfere with the fixed mold 11 in the mold opening direction by the forced mold release mechanism 50, the sliding operation of both slide parts 62 and 63 is performed. Thus, the magnitude of the urging force of the restricting portion 64 and the urging force of the first slide portion 62 are set.

  Hereinafter, an example of an injection molding method using the injection molding apparatus 10 having the above configuration will be described mainly based on FIGS.

  First, as shown in FIG. 1, the molten resin is supplied to the injection space 13 by the injection unit 20 in a state where the movable mold 12 is brought close to the fixed mold 11 and the mold is clamped. At this time, as shown in FIG. 3, the molten resin is injected and supplied into the injection space 13 through a rib-shaped gate 32 provided in the gate block 30 that contacts the nozzle portion 23 of the injection unit 20. . Thereby, the injection space 13 and the gate 32 are filled with the molten resin. Then, the melted resin is solidified by fitting the valve pin 25 to the nozzle part 23 and cooling the filled molten resin in a state in which the nozzle part 23 is closed. For example, the molded product 1 having the shape shown in FIG. (Automobile bumper) is formed. At this time, since the molten resin filled in the gate 32 having a rib shape continuously with the main body of the molded product 1 is also integrally molded, the rib 4 is formed on the back surface 1b of the molded product 1 as shown in FIG. Are integrally molded in a standing state. In addition, a flange-like undercut portion 2 is integrally formed with the molded product 1 at the edges (here, both ends in the width direction) of the molded product 1 (FIGS. 2 and 7). A hole 3 penetrating the collar portion in the vertical direction is formed integrally with the molded product 1 by a pin 61 projecting into the injection space 13 in the collar portion erected on the back surface 1b side from the lower end portion of FIG. 2, FIG. 8).

  After the injection molding of the molded product 1 is completed in this way, a mold opening operation for separating the movable mold 12 from the fixed mold 11 is started, and the molded product 1 is taken out. Here, the fixed mold 11 is provided with a plurality of elastic support portions 42 as the extrusion mechanism 40 of the molded product 1. As the mold opening operation starts, the movable mold 12 moves away from the elastic support portion 42, so that the elastic energy stored in the elastic member 41 during mold clamping is released, and the mold opening direction is increased. The force is applied to the elastic support portion 42 as a force. As a result, as the mold opening operation proceeds, the end surface 1d of the molded product 1 against which the elastic support portion 42 abuts is pressed in the mold opening direction, and the molded product 1 is released from the fixed mold 11 as shown in FIG. Extrude in the direction. When the entire movable mold 12 moves, the plurality of elastic support portions 42 start to extrude the end surface 1d of the molded product 1 corresponding to the same. Thereby, the adhesion state of the molded product 1 to the fixed mold 11 is eliminated, and the molded product 1 is pushed out from the fixed mold 11 to a position separated by a predetermined amount in the mold opening direction.

  Further, in the forced mold release mechanism 50, with the start of the mold opening operation, the restraint by the movable mold 12 is released, and the interaction between the projecting portion 57 forming the guide portion 52 and the fitted portion 58, The second connecting member 55 starts moving outward in the width direction. Thereby, the 1st connection member 55 connected via the 2nd connection member 55 via the connection part 53 starts the movement to the width direction outer side, and the engaging part 56 of the 1st connection member 55 faces the width direction outer side. Is energized. Accordingly, as the mold opening operation proceeds, as shown in FIG. 10, the undercut portion 2 of the molded product 1 that engages with the engaging portion 56 in the width direction receives an urging force to the outside in the width direction. , It is pushed out to the outside with partial deformation. This expansion operation is continued until the undercut portion 2 reaches a position where it does not interfere with the fixed mold 11 in the mold opening direction. Therefore, as described above, by extruding the molded product 1 main body in the mold release direction by the extrusion mechanism 40, the entire molded product 1 is extruded in the mold release direction without the undercut portion 2 being caught by the fixed mold 11. .

  Further, in the pin pulling mechanism 60, the restraint state by the movable mold 12 is released with the start of the mold opening operation, so the first slide portion 62 elastically supported by the fixed mold 11 starts moving in the mold opening direction. However, the first slide portion 62 is still in contact with the restricting portion 64 provided on the movable mold 12 and is in a state of receiving an urging force (regulating force) in the mold clamping direction from the restricting portion 64. . Therefore, as shown in FIG. 11, even when the mold opening operation has progressed to some extent, the first slide part 62 is held at the position during mold clamping (molding) and is supported by the first slide part 62. The area around the hole 3 of the molded product 1 in a state of being fitted with the slide portion 63 and the pin 61 and the pin 61 is held at the position at the time of molding.

  Then, the mold opening operation further proceeds. For example, after the time when the undercut portion 2 of the molded product 1 is expanded to a position where it does not interfere with the fixed die 11, the biasing force of the restricting portion 64 is applied to the first slide portion 62. By being below the force, as shown in FIG. 12, the first slide portion 62 starts a sliding operation in the mold opening direction. Accordingly, the second slide portion 63 elastically supported by the first slide portion 62 starts to slide in the mold opening direction while being pressed against the tapered guide surface 17 formed in the accommodating portion 16 of the fixed mold 11. Therefore, the second slide part 63 also starts to move in a direction away from the molded product 1 outward in the width direction. Therefore, as the mold opening operation further proceeds, the pin 61 provided on the second slide portion 63 moves outward in the width direction, and the pin 61 is pulled out from the hole 3. Therefore, as described above, by extruding the molded product 1 main body in the mold release direction by the extrusion mechanism 40, the entire molded product 1 is extruded in the mold release direction without the pin 61 being caught by the molded product 1. In the present embodiment, a protruding portion is formed on the outer side in the width direction from the surface 1a side of the flange portion formed at the lower end portion of the molded product 1, and the protruding portion is engaged with the first slide portion 62 in the mold opening direction. Since they are aligned (see FIG. 12), the molded product 1 is pushed out in the mold opening direction as the first slide portion 62 slides. Therefore, the burden on the pin 61 is reduced as compared with the case where the hole 3 of the molded product 1 is pushed out in the mold opening direction only by the pin 61.

  As a result of the above action, the entire molded product 1 is in a state where the contact state or engagement state with the fixed mold 11 of the entire molded product 1 including the undercut portion 2 and the hole 3 is eliminated, as shown in FIG. A predetermined amount is pushed in the mold release direction. Therefore, from this state, for example, a transfer means such as a material handling tool is inserted between the fixed mold 11 and the movable mold 12 and the molded product 1 is held, whereby the molded product 1 is taken out from the injection molding apparatus 10. Thereby, the mold release operation of the molded product 1 is completed.

  As described above, in the injection molding apparatus 10 according to the present invention, the extrusion mechanism 40 is disposed on the core side with the fixed mold 11 as a core, and the extrusion mechanism 40 is operated in a predetermined manner along with the mold clamping and mold opening operations. It comprised with the some elastic support part 42 which performs. That is, the plurality of elastic support portions 42 constituting the extrusion mechanism 40 are pushed into the movable mold 12 as a cavity at the time of mold clamping, thereby moving the end surface 1d on the core side of the molded product 1 to a position where it can be molded, The end surface 1 d of the molded product 1 is molded by the molding surface 44. Then, when injection molding is completed and mold opening is started, the cavity that becomes the movable mold 12 moves away from the core with respect to the core that is the fixed mold 11, so the elastic support portion 42 that has been pushed into the cavity is The end face 1d of the molded product 1 is pressed in the mold opening direction with the elastic restoring force stored in the elastic member 41 during mold clamping. As described above, the contact state between the back surface 1b of the molded product 1 and the fixed mold 11 is eliminated at a plurality of locations, and the entire molded product 1 can be extruded in the mold release direction by the amount of movement of the elastic support portion 42. Therefore, it can be easily and reliably removed from between the molds. In this way, the end face 1d can be molded with the clamping force, and a pressing force that can eliminate the close contact state between the molded product 1 and the core (fixed die 11) is molded with the elastic restoring force stored at the time of clamping. Since it can be applied to the product 1, the size can be greatly reduced as compared with a conventional extrusion mechanism in which each extrusion pin needs to be driven by a driving means separate from the mold. Moreover, since it is not necessary to penetrate the whole metal mold | die like an extrusion pin, the rigidity fall of a metal mold | die can also be prevented.

  In the present embodiment, in addition to the extrusion mechanism 40 having the above-described configuration, the forced demolding mechanism 50 having the slide member 51 and the guide portion 52 is provided. Therefore, the undercut portion 2 is formed as a molded product when the mold is opened. The molded product 1 having the undercut portion 2 can be safely released without being forcibly removed by pushing it outward in the width direction. In particular, since the undercut portion 2 is provided at the edge of the molded product 1, the molded product 1 is gradually peeled off from the core starting from the edge by pushing and expanding the undercut portion 2. Go. As a result, air can be drawn between the core and the molded product 1 to prompt release of the molded product 1, so that the molded product 1 can be more easily released from the core by the extrusion operation by the elastic support portion 42. be able to.

In particular, in this embodiment, since the mold clamping force or the mold opening force is used as the driving force in all of the extrusion mechanism 40, the forced mold release mechanism 50, and the pin pulling mechanism 60, separate driving is performed at the time of mold release. There is no need for any means, which makes it possible to further simplify and miniaturize the injection molding apparatus 10.

  As mentioned above, although one Embodiment of this invention was described, this invention can also take a structure other than the above in the range which does not deviate from the meaning.

  For example, in the above embodiment, the case where the entire end surface 1d formed around one opening is formed by one elastic support portion 42 and is configured to be extrudable (FIG. 9) is illustrated. It is not restricted to this form. For example, as shown in FIG. 14, it is also possible to form a part of the end face 1d formed around one opening with two or more elastic support portions 42 so as to be extrudable. Thus, if the opening can be pushed out in the mold release direction by pressing a part of the end face 1d with the elastic support portion 42, it is not always necessary to push out the entire end face 1d. In this way, it is not necessary to design the molding surface 44 of the elastic support portion 42 in accordance with the shape of the opening. In other words, it is possible to use the elastic support portion 42 having the same shape regardless of the extruded portion, thereby reducing the production cost.

  Moreover, although the said embodiment illustrated the case where the some elastic support part 42 which comprises the extrusion mechanism 40 was installed in the location corresponding to the opening part of the molded article 1, such as the grill part 5 and the lamp attachment hole 6, of course. As long as the movable mold 12 serving as the cavity can be brought into contact, the elastic support portion 42 can be installed at other locations, for example, at the edges (upper and lower ends, both ends in the width direction) of the molded product 1. Or it is also possible to install the elastic support part 42 of the said structure in both an opening part and an edge part.

  Moreover, although the case where the bumper for motor vehicles was shape | molded as the molded article 1 was illustrated in the above description, of course, this invention is applicable also to the injection molding of other molded articles. That is, it can be applied to various resin parts such as interior parts such as an instrument panel as well as outer plate parts such as a bumper. Of course, the present invention can be applied not only to large parts but also to small parts.

DESCRIPTION OF SYMBOLS 1 Molded product 1a Front surface 1b Back surface 1c Character line 1d End surface 2 Undercut part 3 Hole 4 Rib 5 Grill part 6 Lamp mounting hole 10 Injection molding apparatus 11 Fixed mold 12 Movable mold 13 Injection space 20 Injection unit 22 Hot runner 23 Nozzle part 30 Gate block 32 Gate 40 Extrusion mechanism 41 Elastic member 42 Elastic support portion 44 Molding surface 50 Forced mold release mechanism 51 Slide member 52 Guide portion 53 Connection portion 54, 55 Connection member 56 Engagement portion 60 Pin pulling mechanism 61 Pins 62, 63 Slide Part 64 Regulatory Department

Claims (3)

A fixed mold, a movable mold, an injection unit for injecting and supplying molten resin between the fixed mold and the movable mold at the time of mold clamping, and molding formed by solidification of the molten resin injected and supplied by the injection unit In an injection molding apparatus equipped with an extrusion mechanism for extruding a product in the mold release direction,
The fixed mold is a core, the movable mold is a cavity, and the extrusion mechanism is disposed on the core side.
The extrusion mechanism has a plurality of elastic support portions that are elastically supported by the fixed mold, and the elastic support portions are pushed into the cavities at the time of mold clamping so that the end surface on the core side of the molded product is An injection molding apparatus characterized by being movable to a moldable position.   2. At least a part of the plurality of elastic support portions is disposed at a position where an end surface on the core side of an opening formed in the molded product can be molded by being pushed by the cavity during mold clamping. The injection molding apparatus described in 1. A slide member that engages with an undercut portion formed at an edge of the molded product and is slidable in a direction intersecting with the mold opening direction;
The injection molding apparatus according to claim 1, further comprising a guide portion provided in the movable mold and guiding a slide operation in a direction in which the undercut portion of the slide member is expanded in accordance with a mold opening operation.

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