JP4529921B2 - Injection mold - Google Patents

Description

  The present invention relates to an injection mold. More specifically, the present invention relates to an injection mold that can easily attach and replace an outer frame arranged according to the shape of the peripheral edge of a flat molded product and can form a highly accurate flat molded product. .

  Injection molded products are used in a wide range from general-purpose to precision applications such as daily necessities, automobile parts, home appliance parts, electronic parts, and optical equipment. The quality of the injection-molded product and the quality of the productivity largely depend on the quality of the mold. Production of injection molds requires advanced technology in all aspects, such as machining accuracy, quality uniformity, and productivity.

  Injection molds have a relatively long delivery time and are expensive, so the burden of amortizing the mold for injection molded products is large. In addition, if the mold is replaced every time the molded product is switched, the labor and time loss are large, and the operation rate of the injection molding machine is reduced. In particular, in the case of flat molded products such as light diffusing plates and light guide plates used in liquid crystal display devices, even if the liquid crystal display device is the same size, the peripheral portion of the flat molded product is different due to differences in the mounting method to the device. Since the shape of the so-called Mimi is different, in the injection mold, multiple types of outer frames with different shapes are prepared, and by replacing the outer frames, different shapes and dimensions can be obtained using the same mold. Attempts have been made to form flat plate molded products.

  For example, Patent Document 1 includes a core plate and an outer frame provided on four sides around the core plate, the outer frame having a configuration in which a plurality of types having different width dimensions and shapes can be exchanged, and the core An injection mold for disposing a plurality of types of flat plate inserts having different dimensions between a plate and an outer frame is disclosed. According to such an injection mold, two or more types of flat plate molded products having different effective areas can be formed by appropriately arranging flat plate inserts on the outer periphery of the core plate. Moreover, the external shape of a flat plate molded product can be changed by exchanging the outer frame with a different shape.

  Specifically, such an injection mold has a structure as shown in FIGS. 16 and 17 and is assembled by the following procedure. FIG. 16 is a cross-sectional view schematically showing a part of the configuration of a conventional injection mold. FIG. 17 is an exploded cross-sectional view schematically showing how the injection mold is assembled. Note that the injection mold shown in FIGS. 16 and 17 has a configuration in which the flat plate insert is not used.

  As shown in FIG. 16, a conventional injection mold 100 includes a mold plate 110, a core plate 120 disposed at a substantially central position of a main surface 110X (upper surface in the drawing) of the mold plate 110, and a core plate. An outer frame 130 disposed on the outer periphery of 120 (right side in the drawing) and an outer peripheral support frame 140 disposed on an outer peripheral portion of the template 110 are provided.

  A plurality of types of outer frames 130 having different shapes are prepared. The outer frame 130 is attached to the main surface 110X of the template 110 by bolts 101 extending substantially parallel to the normal line of the template 110, and a plurality of bolts 102 extending substantially parallel to the main surface 110X of the template 110. Thus, the outer peripheral portion of the core plate 120 is attached.

  The outer peripheral support frame 140 has a recess 141 that fits into a positioning member 150 (pin or key) provided on the main surface 110X of the template 110. The outer peripheral support frame 140 is attached to the main surface 110X of the template 110 with bolts 103 extending substantially parallel to the normal line of the template 110 in a state where the positioning member 150 and the recess 141 are fitted.

A procedure for assembling such an injection mold 100 will be described.
As shown in FIG. 17, first, the core plate 120 is attached to the main surface 110X of the template 110, and then the outer frame 130 is disposed adjacent to the outer periphery of the core plate 120. 110 is attached. At this time, there is almost no step between the upper surface 120X of the core plate 120 and the upper surface 130X of the cutout portion of the outer frame 130.

  Next, the outer frame 130 is pressed toward the core plate 120 by these bolts 102 while adjusting the tightening degree between the plurality of bolts 102. Next, the outer peripheral support frame 140 is disposed on the main surface 110X of the template 110 so that the concave portion 141 of the outer peripheral support frame 140 is fitted to the positioning member 150 provided on the template 110, and in this state, The outer peripheral support frame 140 is attached to the main surface 110X of the template 110 with the bolts 103.

JP 2004-188612 A

  However, in such an injection mold 100, the adjustment of the tightening degree between the plurality of bolts 102, which is performed when the outer frame 130 is pressed against the core plate 120, is very complicated, and the outer frame 130 is attached. Was complicated. In particular, when the adjustment of the tightening condition of these bolts 102 is insufficient, flash may occur in the flat plate molded product, and the accuracy of the flat plate molded product may be lowered. When the outer frame 130 is replaced with a different shape, the outer peripheral support frame 140 must be removed from the template 110 in order to loosen the bolts 102 extending substantially parallel to the main surface 110X of the template 110. There is also a problem that the work becomes complicated because it does not become necessary.

  An object of the present invention is to provide an injection mold capable of easily attaching and exchanging an outer frame arranged in accordance with the shape of the peripheral portion of a flat molded product and forming a highly accurate flat molded product. There is.

  In order to solve the above-described problems and achieve the object, an injection mold according to claim 1 of the present invention includes a fixed mold and a movable mold, and is an injection mold for forming a flat molded product. A mold plate, wherein the fixed mold and the movable mold each have a mold plate, and a core plate that is detachably attached to a main surface of one of the fixed mold and the movable mold; An outer frame that is disposed adjacent to the outer periphery of the core plate and is detachably attached to the main surface of the template A, an outer peripheral support frame that is detachably attached to an outer peripheral portion of the template A, and the template An insertion member that is inserted between the outer frame and the outer peripheral support frame in a state of being in contact with the outer frame and the outer peripheral support frame on the main surface side of A; By pressing to the main surface side, the reaction force from the outer peripheral support frame Characterized in that it and a pressing means for pressing the outer frame to the core plate side Te. The direction in which the insertion member is inserted may be a direction perpendicular to the main surface of the template, or a direction parallel to the main surface of the template.

  In the injection mold according to claim 2 of the present invention, the contact surface between the outer peripheral support frame and the insertion member is inclined toward the outer peripheral support frame. To do.

  In the injection mold according to claim 3 of the present invention, a contact surface between the outer frame and the insertion member is inclined toward the outer frame.

  Moreover, in the injection mold according to claim 4 of the present invention, the flat plate molded product is an optical member.

  The injection mold according to claim 5 of the present invention is characterized in that the optical member is a light diffusion plate or a light guide plate made of a thermoplastic resin.

  In the injection mold according to claim 6 of the present invention, the cavity surface of the core plate, the cavity surface of the stationary mold plate, and the cavity surface of the movable mold plate A pattern forming portion for imparting a pattern shape to the surface of the flat molded product is formed on at least one of the cavity surfaces.

  In the injection mold according to claim 7 of the present invention, the cavity surface of the core plate, the cavity surface of the fixed mold plate, the cavity surface of the movable mold plate, A pattern forming member for imparting a pattern shape to the surface of the flat plate molded article is disposed at a position corresponding to at least one of the cavity surfaces.

  According to the injection mold of the present invention, when the outer frame is attached according to the shape of the peripheral edge of the flat plate molded product, the outer frame and the outer peripheral support frame are in contact with the outer frame and the outer peripheral support frame. In order to press the outer frame toward the core plate with this insertion member by inserting the insertion member with the pressing means, adjust the tightening degree between the bolts as in the case of using conventional bolts There is no need, and the attaching operation can be performed easily.

  In addition, when replacing the outer frame, it is possible to release the pressing of the outer frame toward the core plate only by taking out the insertion member, and there is no need to remove the outer peripheral support frame as in the prior art. Exchange work can be performed easily.

  Furthermore, since the outer frame is pressed toward the core plate with the entire insertion member as compared with the case where the outer frame is pressed toward the core plate with a plurality of bolts, the outer frame can be pressed toward the core plate with a uniform force. For this reason, the clearance gap between an outer frame and a core plate can be made uniform, and, thereby, the highly accurate flat plate molded product without a flash can be formed. Further, the compressed air blown from the gap can be blown out uniformly, and the release of the flat molded product can be performed reliably.

  Hereinafter, an injection mold according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an injection mold 1 according to the present embodiment. As shown in FIG. 1, an injection mold 1 is for forming a flat plate molded product made of a thermoplastic resin. The injection mold 1 is attached to either the fixed mold 10 or the movable mold 20 between the fixed mold 10, the movable mold 20 that can move forward and backward with respect to the fixed mold 10, and the fixed mold 10 and the movable mold 20. The middle plate 30 is provided.

  The fixed mold 10 includes a fixed mold plate 11, a stripper plate 12, and a mounting plate 13 for attaching the fixed mold plate 11 and the stripper plate 12 to a fixed die plate (not shown) of an injection molding machine. . The stripper plate 12 and the mounting plate 13 are formed with a sprue 12A for injecting a thermoplastic resin. The fixed template 11 is formed with a runner 11A and a gate 11B that communicate with the sprue 12A. The fixed mold plate 11 is configured to be movable forward and backward with respect to the stripper plate 12 and the mounting plate 13. The stripper plate 12 is configured to advance and retract with respect to the mounting plate 13. The movable mold 20 includes a movable mold plate 21 and an attachment plate 22 for attaching the movable mold plate 21 to a movable die plate (not shown) of the injection molding machine.

  FIG. 2 is a schematic perspective view showing the middle plate 30 attached to the fixed mold plate 11, and FIG. 3 is a partial cross-sectional view thereof. As shown in FIGS. 2 and 3, the middle plate 30 includes a core plate 31 detachably attached to a substantially central position of a main surface (upper surface in the drawing) 11 </ b> X of the fixed mold plate 11, and an outer periphery of the core plate 31. Four outer frames 32 arranged adjacent to each other, an outer peripheral support block 33 as an outer peripheral support frame that is detachably attached to an outer peripheral portion of the fixed mold 11 on the main surface 11X side, and a main surface of the fixed mold 11 On the 11X side, a locking block 34 as an insertion member inserted between the outer frame 32 and the outer peripheral support block 33 is provided.

  As shown in FIG. 3, the outer frame 32 has a shape in which a part of a rectangular vertex is cut out in a rectangular shape, and a bolt that extends substantially parallel to the normal line of the fixed template 11 from the upper surface 32 </ b> X side. By 4a, it attaches to the main surface 11X side of the fixed template 11 so that attachment or detachment is possible. At this time, the upper surface 32Y (that is, the surface that is one step lower than the upper surface 32A) of the cutout portion of the outer frame 32 is substantially flush with the upper surface 31X of the core plate.

The outer peripheral support block 33 is formed in a trapezoidal cross section.
FIG. 4 is an exploded cross-sectional view showing the locking block 34 and the outer peripheral support block 33. As shown in FIGS. 3 and 4, in the outer periphery support block 33, the outer surface 33 </ b> A that is a surface on the outer periphery side (right side in FIG. 4) is a surface substantially perpendicular to the main surface 11 </ b> X of the fixed template 11. The inner side surface 33B, which is the surface on the side of the locking block 34 located on the side opposite to the outer side surface 33A, is a slope inclined at an angle θ degree with respect to the outer side surface 33A.

  Further, as shown in FIG. 3, a positioning recess 33 </ b> C is formed on the lower surface 33 </ b> Y of the outer peripheral support block 33. On the other hand, a convex positioning member 35 projecting upward in FIG. 3 is provided on the outer peripheral side of the main surface 11X of the fixed mold plate 11. The outer peripheral support block 33 is positioned and arranged with respect to the fixed mold plate 11 by fitting the concave portion 33 </ b> C to the positioning member 35.

  The outer peripheral support block 33 thus positioned is detachably attached to the main surface 11X of the fixed mold plate 11 from the upper surface 33X side by a bolt 6a extending substantially parallel to the outer surface 33A. At this time, the upper surface 33 </ b> X of the outer peripheral support block 33 is substantially at the same height as the upper surface 32 </ b> X of the outer frame 32.

  The locking block 34 is formed in a wedge shape (inverted trapezoidal shape) in cross section. Accordingly, the contact surface between the outer periphery support block 33 and the locking block 34 is inclined from the surface substantially perpendicular to the main surface of the fixed mold plate 11 to the outer periphery support block 33 side (outside) in FIG. .

  As shown in FIGS. 3 and 4, in the rocking block 34, the outer side surface 34 </ b> A that is the surface on the outer peripheral support block 33 side is substantially parallel to the inner side surface 33 </ b> B that is the inclined surface of the outer peripheral support block 33. The inner side surface 34B, which is the surface on the outer frame 33 side, is a vertical surface that is substantially perpendicular to the main surface 11X of the fixed mold plate 11, similarly to the outer surface 32 A of the outer frame 32. .

  Here, the angle θ between the outer side surface 34A of the locking block 34 and the inner side surface 33B of the outer peripheral support block 33 is preferably in the range of 5 to 30 degrees, more preferably 10 to 20 degrees, and further preferably 13 to 17 degrees. By setting the angle θ within these ranges, the outer frame 32 can be efficiently pressed against the core plate 31.

  As shown in FIG. 3, when the locking block 34 is inserted between the outer frame 32 and the outer peripheral support block 33, the outer side surface 34 </ b> A of the locking block 34 abuts on the inner side surface 33 </ b> B of the outer peripheral support block 33, The inner side surface 34B of the block 34 is in contact with the outer side surface 32A of the outer frame 32.

  The locking block 34 is pressed from the upper surface 34X side to the main surface 11X side of the fixed mold plate 11 by a bolt 5a as a pressing means extending substantially parallel to the other bolts 4a and 6a. Removably attached to.

  The middle plate 30 is assembled as follows. FIG. 5 is an exploded cross-sectional view showing a state in which the middle plate is exploded in FIG. 3. As shown in FIG. 5, first, the core plate 31 is attached to the main surface 11 </ b> X of the fixed mold plate 11. Next, the outer peripheral support block 33 is positioned by fitting the concave portion 33 </ b> C of the outer peripheral support block 33 to the positioning member 35 provided on the main surface 11 </ b> X of the fixed mold plate 11. In this state, the outer peripheral support block 33 is attached to the main surface 11X of the fixed mold plate 11 with the bolt 6a.

  The Rockwell hardness (HRC: JIS Z2245-2005 C scale) of the locking block 34 is preferably 100% to 20% compared to the hardness of the material of the outer frame 32 and / or the outer peripheral support block 33, More preferably, it is 80% to 30%. If the Rockwell hardness of the locking block 34 is greater than 100%, the outer frame 32 or the like may be damaged and the accuracy may be reduced. If it is less than 20%, the function as the locking block 34 becomes insufficient and the durability is increased. May be inferior.

  Further, the surface roughness of the outer surface 34A that is a contact surface with the outer peripheral support block 33 and the inner surface 34B that is the contact surface with the outer frame 32 in the locking block 34 is the arithmetic average roughness ( Ra) is preferably 0.02 μm (mirror surface) to 200 μm, and more preferably 0.1 to 100 μm. When the arithmetic average roughness of the abutting surface is less than 0.02 μm, the frictional force between the abutting surfaces is increased, and it may be difficult to remove the locking block 34. On the other hand, when the arithmetic average roughness of the contact surface is larger than 200 μm, the positional accuracy between the members may be lowered, and the durability is lowered.

  In general, grease or the like is used between the members for easy removal. However, if the molded product is an optical member, it may become a defective product if the molded product adheres to the molded product. Can not. Instead, the surface roughness of each member is controlled as described above.

  Next, the outer frame 32 is disposed adjacent to the outer periphery of the core plate 31, and the outer frame 32 is attached to the main surface 11 </ b> X of the fixed template 11 with the bolt 4 a. At this time, no step is generated between the upper surface 31X of the core plate 31 and the upper surface 32Y of the cutout portion of the outer frame 32.

  Next, the locking block 34 is inserted between the outer frame 32 and the outer periphery support block 33, the inner surface 34B of the locking block and the outer surface 32A of the outer frame 32 are brought into contact, and the outer surface 34A of the locking block and the outer periphery The inner side surface 33B of the support block 33 is brought into contact. In this state, the locking block 34 is pressed toward the main surface 11X side of the fixed template 11 by tightening the bolt 5a. As described above, when the bolt 5a is tightened and the locking block 34 is pressed, the surfaces 34A and 33B and the surfaces 34B and 32A come into contact with each other, and the locking block 34 moves to the fixed mold plate 11 side. At this time, the locking block 33 presses the outer frame 32 toward the core plate 31 due to a reaction caused by the inner side 34 </ b> A of the locking block 34 pressing the outer side 33 </ b> B of the outer peripheral support block 33. In this state, the locking block 34 is attached to the main surface 11X side of the fixed template 11.

  In this way, the locking block 34 presses the outer frame 32 toward the core plate 31, but the outer side surface 34 </ b> A of the locking block 34 presses the inner side surface 33 </ b> B of the outer peripheral support block 33. The outer frame 32 can be pressed to the core plate 31 side with a uniform force along the longitudinal direction of 32. For this reason, the clearance gap between the core plate 31 and the outer frame 32 can be made uniform, and it can suppress that a flash etc. arise in a flat plate molded product.

  Incidentally, as shown in FIG. 6, a notch 32 </ b> P is formed on the inner side surface 32 </ b> B that is the surface on the core plate 31 side of the outer frame 32. Further, an air blowing port 32S is provided adjacent to the notch 32P, and guides compressed air, which is release air for releasing the molded flat plate product from the core plate 31, to the notch 32P. Since the compressed air is blown out uniformly at the notch 32P, it is very easy to release and take out the molded flat molded product.

  Further, the upper surface 32X of the outer frame 32 is formed with a groove 32U for discharging a gaseous pyrolyzate that can be generated from the molten resin when forming a flat molded product. Thereby, it can prevent that a bubble etc. arise in a flat plate molded product, and can raise the precision of a molded product.

  By the way, as shown in FIGS. 7-10, in order to prevent the position shift of the core plate 31 and the fixed mold plate 11, the key 36 can be used as a positioning member. When such a key 36 is arranged, the key 36 is later moved when either the core plate 31 or the fixed mold plate 11 is heated and expanded or cooled and contracted. It is preferable to have a structure capable of escaping thermal expansion and contraction so that distortion or the like does not occur in the other member that expands or contracts. As such a structure, for example, as shown in FIGS. 7 and 8, a key 36 is disposed in a groove 11 </ b> C formed at one central portion of the fixed mold 11, and the core plate 31 is supported at this single point. It can be.

  Further, for example, as shown in FIGS. 9 and 10, the positioning member is composed of a key 36 and a key 37, and the key 36 is disposed in the groove 11C at one central portion of the fixed mold plate 11. One direction from this central portion is arranged. Alternatively, the rectangular key 37 may be disposed in the groove 11D formed in the radiating portion at a line symmetrical position extending in the other direction opposite to the one direction. In other words, a groove 11 </ b> D having a size larger than that of the key 37 and extending in parallel with the one and other directions can be formed between the fixed mold plate 11 and the core plate 31. Therefore, since the dimension of the groove 11D is longer than the dimension of the radiating part key 37 in the longitudinal direction of the fixed mold plate 11, even if either the core plate 31 or the fixed mold plate 11 expands or contracts, Thermal expansion and contraction can be released, and distortion and the like can be prevented.

  Next, the case where the outer frame 32 is removed will be described. For example, flat plate molded products such as a light diffusion plate and a light guide plate used in a liquid crystal display device differ in the shape of the peripheral portion of the flat plate molded product, that is, the so-called “mimi” due to the difference in the mounting method to the device. For example, as shown in FIGS. 11 to 13, the shape of the peripheral edge portion is different in the flat plate molded products 24 a to 24 c. For such flat plate molded products 24a to 24c, by using the same core plate 31 and replacing the outer frame 32 according to the shape of the peripheral portion, the flat plate molded products 24a to 24c having different Mimi shapes are obtained. Can be molded.

  In order to replace the outer frame 32, in FIG. 3, first, the locking block 34 is removed from the fixed template 11 by loosening the bolt 5a. At this time, since the pressing from the locking block 34 to the outer frame 32 is released, the bolt 4a can be easily loosened. For this reason, the outer frame 32 can be easily removed from the fixed mold 11 without removing the outer peripheral support block 33 from the fixed mold 11 by simply loosening the bolt 4 a. Therefore, in the injection mold 1 of the present embodiment, the outer frame 32 can be removed simply by removing the locking block 34. Therefore, the outer frame 32 can be easily replaced, and the operation is simplified.

  Next, a procedure for forming a flat plate molded product using the injection mold 1 will be described. 14 and 15 are schematic views for explaining an operation of forming a flat plate molded product using an injection mold. As shown in FIG. 1, first, in a state in which the fixed mold 10 and the movable mold 20 are closed, a molten thermoplastic resin is injected from above the mounting plate 13, and is passed through the sprue 12A, the runner 11A, and the gate 11B. Fill the cavity with molten resin.

  Next, after the molten resin is cooled and solidified, as shown in FIG. 14, the movable mold 20 is moved backward to open the space between the movable mold plate 21 and the middle plate 30 to expose the flat plate molded product X. . Next, as shown in FIG. 15, the movable mold plate 21 is further retracted to open the space between the fixed mold plate 11 and the stripper plate 12, and the thermoplastic resin in the pinpoint gate portion is cut.

  Further, compressed air as mold release air is blown out from the notch 32P of the outer frame 32 shown in FIG. 6, and the flat plate molded product X is released from the middle plate 30 and taken out. Finally, portions corresponding to the sprue 12A, the runner 11A, and the gate 11B are taken out by a robot or the like, and then the movable mold 20 and the fixed mold 10 are closed to complete one cycle of injection molding. A flat plate molded product can be obtained as described above.

  In addition, when shifting to the manufacture of a flat plate product having a different shape or size of the peripheral portion, after removing the outer frame 32 used in the above-described procedure, the peripheral shape of the flat plate product is converted in the above-described procedure. Replace with the corresponding outer frame 32.

  There is no particular limitation on the flat plate molded product formed using the injection mold of the present invention, but it can be suitably applied to a flat plate molded product that requires strict flatness on the surface. A member is preferred. Examples of the optical member include a light diffusing plate, a light guide plate, a reflecting plate, a lighting curtain, a Fresnel lens, and a lenticular lens. The material of the optical member is preferably a thermoplastic resin, and a thermoplastic resin containing a light diffusing agent. Can also be used. The thermoplastic resin is not particularly limited. For example, methacrylic resin, polycarbonate, polystyrene, acrylonitrile-styrene copolymer resin, methyl methacrylate-styrene copolymer resin, resin having an alicyclic structure, aromatic vinyl Examples thereof include a copolymer of a monomer based on an alkyl (meth) acrylate having a lower alkyl group, and polyethersulfone.

  Among these, a resin having an alicyclic structure and a copolymer of an aromatic vinyl monomer and a (meth) acrylate alkyl monomer having a lower alkyl group can be suitably used. A resin having a cyclic structure can be particularly preferably used. Resin with alicyclic structure has good flowability of molten resin, so it can fill mold cavity with pinpoint gate and has extremely low hygroscopicity, so it has excellent dimensional stability, flat plate molding Since the product does not warp and the specific gravity is small, the flat plate molded product can be reduced in weight. In addition, (meth) acrylic acid is methacrylic acid and acrylic acid.

In addition, this invention is not limited to the said embodiment.
For example, the injection mold 1 is constituted by three plates of the fixed mold plate 11, the movable mold plate 21, and the middle plate 30, but the middle plate is attached to either the fixed mold plate 11 or the movable mold plate 21. It is good also as a structure which consists of 2 plates provided with 30.

Further, the fixed mold plate 11 may be a hot runner provided with a heating mechanism therein or a cold runner not provided with a heating mechanism.
Further, a pattern forming member for forming a predetermined pattern shape on the surface of the flat plate molded product, for example, a thin plate stamper on which a pattern is formed, is either a cavity surface of the movable mold plate 21 or a cavity surface of the fixed mold plate 11. You may arrange | position in the position corresponded to this surface. The pattern forming member may be disposed on the cavity surface of the core plate 31. In addition, a pattern forming portion for forming a predetermined pattern shape may be directly formed on any one of the cavity surface of the movable mold plate 21 and the cavity surface of the fixed mold plate 11. Further, the pattern forming portion may be directly formed on the cavity surface of the core plate 31. By arranging such a pattern forming member or providing a pattern forming portion, a desired pattern shape can be formed on the surface of the molded product simultaneously with the molding of the flat molded product. Compared with this, man-hours can be reduced.

  Here, the pattern shape is, for example, a concavo-convex shape that diffuses and emits incident light by being formed on the surface of the light diffusion plate when the flat molded product is a light diffusion plate. That is. As a specific shape of the pattern shape, for example, an uneven shape such as a polygonal cross section or a semicircular cross section and a plurality of linear portions extending in a linear shape can be used. Examples of the polygon include a triangle and a quadrangle. In addition to the semicircle, the semicircular shape includes a semi-elliptical shape, a shape having a curved portion in part, and the like. In addition, the pattern shape may be an uneven shape such as a polygonal pyramid (triangular pyramid, quadrangular pyramid, etc.) or hemispherical (a shape having a curved surface in part such as a hemisphere, a semi-elliptical sphere, or a normal surface) Can do. In addition, although the case where these uneven | corrugated shape was formed in the surface of a light diffusing plate was demonstrated, you may form the said uneven | corrugated shape in the surface of other flat plate molded articles other than a light diffusing plate.

  In the embodiment described above, the locking block 34 is pressed to the fixed mold plate 11 side by tightening the bolt 5a. However, the locking block 34 may be pressed by other pressing means such as a hydraulic pressure or a spring. Further, the vertical cross-sectional shape of the locking block 34 is not limited to the above-mentioned cross-sectional wedge shape, and may be other shapes as long as the outer frame 32 can be pressed against the core plate 31 side. Moreover, it does not specifically limit to the shape and dimension of the notch part 32P mentioned above, What is necessary is just to be able to blow off compressed air uniformly.

  Further, in the above-described embodiment, the case where the contact surface between the outer peripheral support block 33 and the locking block 34 is inclined toward the outer peripheral support block 33 side has been described, but the contact surface between the outer frame 32 and the locking block 34 is described. May be inclined to the outer frame 32 side. Furthermore, the contact surface between the outer periphery support block 33 and the locking block 34 may be inclined toward the outer periphery support block 33 side, and at the same time, the contact surface between the outer frame 32 and the locking block 34 may be inclined toward the outer frame 32 side. . In these cases, the inclination angle of the contact surface between the outer frame 32 and the locking block 34 can be in the same preferred range as the angle of the contact surface between the outer peripheral support block 33 and the locking block 34. Specifically, the inclination angle is preferably in the range of 5 to 30 degrees, more preferably 10 to 20 degrees, and further preferably 13 to 17 degrees. Further, on the contact surface between the outer frame 32 and the locking block 34, the hardness, surface roughness, etc. of the outer side surface 32 </ b> A of the outer frame 32 and the inner side surface 34 </ b> B of the locking block 34 are The same preferred range as the hardness and surface roughness of the contact surface. As described above, when the outer frame 32 and the locking block 34 in which the contact surfaces of the outer frame 32 and the locking block 34 are inclined toward the outer frame 32 are used, the locking block 34 is By pressing toward the main surface side of the fixed mold plate 11, the outer frame 32 can be pressed toward the core plate 31 by the reaction force from the outer peripheral support block 33.

  As described above, the injection mold according to the present invention can quickly replace the outer frame with a simplified operation when replacing the outer frame according to the shape of the peripheral edge of the flat plate molded product. Therefore, it is useful for an injection mold for molding flat plate molded products having different peripheral edge shapes. In particular, it is suitable for molding flat molded products such as a light diffusing plate, a light guide plate, and a reflecting plate that require strict flatness.

It is the schematic which shows the metal mold | die for injection molding by embodiment of this invention. It is a schematic perspective view which shows the principal part of the injection mold by embodiment of this invention. It is a fragmentary sectional view which shows the principal part of the metal mold | die for injection molding by embodiment of this invention. It is a general | schematic fragmentary sectional view which shows a locking block and an outer periphery support block. It is a disassembled sectional view which shows the principal part of the injection mold by embodiment of this invention. It is a schematic perspective view which shows an outer frame. It is a schematic plan view which shows a stationary template. It is a schematic sectional drawing which shows a fixed mold plate and a core plate. It is a schematic plan view which shows a stationary template. It is a schematic sectional drawing which shows a fixed mold plate and a core plate. It is a top view which shows a flat plate molded product. It is a top view which shows a flat plate molded product. It is a top view which shows a flat plate molded product. It is the schematic explaining operation which shape | molds a flat plate molded product using the metal mold | die for injection molding. It is the schematic explaining operation which shape | molds a flat plate molded product using the metal mold | die for injection molding. It is a fragmentary sectional view which shows the principal part of the conventional injection mold. It is an exploded sectional view showing the principal part of the conventional injection mold.

Explanation of symbols

1 Injection Mold 4a Bolt 5a Bolt 6a Bolt 10 Fixed Mold 11 Fixed Mold Plate 11A Runner 11B Gate 11C Groove 11D Groove 11X Main Surface 12 Stripper Plate 12A Sprue 13 Mounting Plate 20 Movable Mold 21 Movable Mold Plate 22 Mounting Plate 30 Middle Plate 31 Core plate 31X Upper surface 32 Outer frame 32A Outer side surface 32B Inner side surface 32P Notch 32S Air outlet 32U Groove 32X Upper surface 32Y Upper surface 33 Outer peripheral support block 33A Outer side surface 33B Inner side surface 33C Recessed portion 33X Upper surface 33Y Lower surface 34 Locking block 34A Inner surface 35 Positioning member 36 Key 37 Key X Flat plate molded product

Claims (7)

A mold for injection molding for forming a flat molded product, comprising a fixed mold and a movable mold,
The fixed mold and the movable mold each have a template,
A core plate that is detachably attached to a main surface of the template A of either the fixed mold or the movable mold;
An outer frame disposed adjacent to the outer periphery of the core plate and detachably attached to the main surface of the template A;
An outer peripheral support frame detachably attached to an outer peripheral portion of the template A;
On the main surface side of the template A, an insertion member inserted between the outer frame and the outer peripheral support frame in a state in contact with the outer frame and the outer peripheral support frame;
A pressing means for pressing the outer frame toward the core plate by a reaction force from the outer peripheral support frame by pressing the insertion member toward the main surface of the template A;
An injection mold characterized by comprising:   The injection mold according to claim 1, wherein a contact surface between the outer peripheral support frame and the insertion member is inclined toward the outer peripheral support frame.   The injection mold according to claim 1 or 2, wherein a contact surface between the outer frame and the insertion member is inclined toward the outer frame.   The injection mold according to any one of claims 1 to 3, wherein the flat plate molded article is an optical member.   The injection mold according to claim 4, wherein the optical member is a light diffusion plate or a light guide plate made of a thermoplastic resin.   A pattern shape is imparted to the surface of the flat plate molded product on at least one of the cavity surface of the core plate, the cavity surface of the fixed mold plate, and the cavity surface of the movable mold plate. 6. A mold for injection molding according to any one of claims 1 to 5, wherein a pattern forming portion is formed.   A pattern is formed on the surface of the flat plate molded product at a position corresponding to at least one of the cavity surface of the core plate, the cavity surface of the fixed mold plate, and the cavity surface of the movable mold plate. The mold for injection molding according to any one of claims 1 to 6, wherein a pattern forming member for imparting a shape is disposed.

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