Injection molding method and injection mold for resin molded products

Abstract

To enhance positional accuracy of an insert member in a resin molding.SOLUTION: A movable die 103 is provided with: a slide block 107 capable of advancing to a block advancing position projecting at a movable die side second molding surface 103b; and a positioning pin 111 having a columnar part 111a and capable of advancing to a pin advancing position projecting at the movable die side second molding surface 103b. The slide block 107 is made to advance to the block advancing position and the slide block 107 is made to abut on an insert member 15 from a retraction direction of the positioning pin 111, the positioning pin 111 is made to advance to the pin advancing position and the columnar part 111a of the positioning pin 111 is fit into a positioning hole 20 of the insert member 15, and injection of the resin into a cavity C is started in a preparation state where a fixed die 101 and the movable die 103 are clamped.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an injection molding method and an injection molding die for molding a resin molded product with an insert member inserted therein by injecting and filling a cavity formed between a first molding die, a second molding die and an insert member. [Background technology]

[0002] Patent Document 1 discloses an injection molding method for molding a resin molded product with an insert member inserted therein by injecting and filling a cavity formed between a first mold, a second mold, and an insert member. In this injection molding method, a support member is provided on the first mold so as to be able to protrude from the molding surface of the first mold, and injection of resin into the cavity is started with the insert member placed on the support member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 8-72099 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, when the injection of resin into the cavity begins, the movement of the insert member in a direction perpendicular to the protruding direction of the support member is not restricted, so the injection pressure of the resin may cause the insert member to move in a direction perpendicular to the protruding direction of the support member, which may result in a deterioration in the positional accuracy of the insert member in the resin molded product.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to improve the positional accuracy of an insert member in a resin molded product. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is characterized in that a positioning pin provided on a first molding die can be inserted into a positioning hole of an insert member.

[0007] Specifically, the first to sixth inventions are directed to an injection molding method for molding a resin molded product into which an insert member is inserted by injecting and filling a cavity formed between a first molding die and a second molding die and an insert member, and provide the following solutions.

[0008] That is, in the first invention, one of the first molding die and the second molding die is provided with a slide block which can advance and retreat between a block advance position protruding from the molding surface of the one molding die and a block retract position retracted from the block advance position in the anti-protruding direction, the first molding die is provided with a positioning pin which has a columnar portion and can advance and retreat between a pin advance position protruding from the molding surface of the first molding die and a pin retract position retracted from the pin advance position in the anti-protruding direction, and the insert member is formed with a positioning hole, and the slide block is advanced to the block advance position to contact the insert member from the advancement direction or the retraction direction of the positioning pin. the positioning pin is brought into contact with the positioning hole of the insert member, the positioning pin is advanced to the pin advanced position so that the columnar portion of the positioning pin is fitted into the positioning hole of the insert member, and in the preparatory state in which the first molding die and the second molding die are clamped, injection of resin into the cavity is started, and thereafter, before the injection of resin into the cavity is completed, the positioning pin is retracted to the pin retracted position so that the entire columnar portion of the positioning pin is released from the positioning hole of the insert member, and the slide block is retracted to the block retracted position so as to be separated from the insert member, and the resin is also filled in the space formed by the retraction of the positioning pin and the slide block.

[0009] A second invention is a method for injection molding a resin molded product according to the first invention, wherein the one molding die is the first molding die, the slide block has a pin insertion hole formed therethrough in the advancing and retreating direction of the slide block, the positioning pin is inserted into the pin insertion hole of the slide block, the slide block and the positioning pin are capable of advancing and retreating in a common advancing direction and a common retreating direction, the first molding die is further provided with a pin biasing means for biasing the positioning pin in the common retreating direction, a block biasing means for biasing the slide block in the common retreating direction, and a cam member abutting against the positioning pin and the slide block from the common retreating direction, and a first surface portion and a second surface portion located in the common retreating direction relative to the first surface portion are formed on an abutting surface of the cam member with the positioning pin and the slide block in sequence from one side in an orthogonal direction substantially orthogonal to the penetrating direction of the pin insertion hole, and a groove portion extending in the orthogonal direction is formed in the second surface portion, Between the first surface portion, the second surface portion, and a bottom surface of the groove portion, an inclined surface portion is formed which inclines in the common retreat direction toward the other of the perpendicular directions, and the cam member is slidable between a first slide position in which the first surface portion abuts against the positioning pin and the slide block, advancing the positioning pin to the pin advanced position against the biasing force of the pin biasing means, and advancing the slide block to the block advanced position against the biasing force of the block biasing means, and a second slide position in which the bottom surface of the groove abuts against the positioning pin, retracting the positioning pin to the pin retracted position, and a non-groove portion forming area of ​​the second surface portion abuts against the slide block, and retracting the slide block to the block retracted position, and in the preparatory state, the cam member is disposed at the first slide position, and the cam member is slid from the first slide position to the second slide position between the start and end of injection of resin into the cavity.

[0010] The third invention is characterized in that, in the injection molding method for a resin molded product relating to the first or second invention, a tapered portion which gradually becomes narrower in the protruding direction is formed continuously with the columnar portion at the protruding side end of the positioning pin.

[0011] A fourth invention is characterized in that, in the injection molding method for a resin molded product relating to the third invention, in the preparatory state, there is a gap between the tapered portion of the positioning pin and the molding surface of the second mold.

[0012] A fifth invention is characterized in that, in the injection molding method for a resin molded product relating to the third or fourth invention, the positioning pin causes the entire tapered portion to protrude from the molding surface of the first mold when the pin is in the retracted position.

[0013] A sixth invention is characterized in that in the injection molding method for a resin molded product according to any one of the first to fifth inventions, a recess is formed in the resin molded product, and before the resin molded product is released, the positioning pin is retracted from a position where it engages with the recess in the resin molded product to prevent the release of the resin molded product, to a non-protruding position where it does not protrude from the molding surface of the first mold, thereby enabling the resin molded product to be released.

[0014] The seventh invention is an injection molding die comprising a first molding die and a second molding die, and configured to mold a resin molded product with an insert member inserted therein by injecting and filling a cavity formed between the first molding die and the second molding die and an insert member, wherein one of the first molding die and the second molding die is provided with a slide block that can advance and retreat between a block advance position that protrudes from the molding surface of the one molding die and a block retract position that retracts in the opposite protruding direction from the block advance position, and the first molding die is provided with a positioning pin having a columnar portion and that can advance and retreat between a pin advance position that protrudes from the molding surface of the first molding die and a pin retract position that retracts in the opposite protruding direction from the pin advance position. Effect of the Invention

[0015] According to the first invention, when the injection of resin into the cavity begins, the positioning pin prevents the insert member from moving in a direction perpendicular to the advancement and retreat direction of the positioning pin due to the injection pressure of the resin, thereby improving the positional accuracy of the insert member in the resin molded product.

[0016] Furthermore, when the injection of resin into the cavity starts, the slide block is brought into contact with the insert member from the advancing or retreating direction of the positioning pin, thereby enabling the insert member to be positioned in the advancing / retracting direction of the positioning pin.

[0017] In addition, before the injection of resin into the cavity is completed, the positioning pin is retracted to remove the entire columnar portion from the positioning hole of the insert member, and the space formed by the retraction of the positioning pin is also filled with resin, so that the positioning hole of the insert member can be covered with resin.

[0018] In addition, before the injection of resin into the cavity is completed, the slide block is retracted away from the insert member and the space formed by the retraction of the slide block is also filled with resin, so that the contact point between the insert member and the slide block in the prepared state can be covered with resin.

[0019] According to the second invention, the positioning pin and the slide block are advanced and retreated by the sliding action of the cam member, so that the first molding die can be made smaller and equipment costs can be reduced, compared to when they are advanced and retreated by a hydraulic system.

[0020] According to the third invention, the positioning pin can be more easily inserted into the positioning hole of the insert member, compared to when the protruding end face of the positioning pin is a flat surface of the same size and shape as the opening of the positioning hole of the insert member.

[0021] According to the fourth aspect of the present invention, since the molding surface of the second mold is not damaged by the tapered portion of the positioning pin, it is possible to provide the molding surface of the second mold with irregularities, and to form a grain pattern on the surface of the resin molding surface by the irregularities, etc. Therefore, the degree of freedom in designing the resin molded product is increased.

[0022] According to the fifth invention, when the positioning pin is in the retracted position, no protrusions are formed at the locations of the resin molded product corresponding to the positioning pin, making it possible to reduce the amount of resin used and save on material costs, compared to when the tapered portion of the positioning pin is retracted further than the molding surface of the first mold.

[0023] According to the sixth aspect of the present invention, the position of the positioning pin at the end of injection of the resin into the cavity can be set to a position that prevents the resin molded product from being released from the mold, thereby increasing the degree of freedom in the shape of the resin molded product.

[0024] According to the seventh invention, when a positioning hole into which the columnar portion of the positioning pin is fitted is formed in the insert member, the slide block is advanced to the block advance position, the slide block is abutted against the insert member from the advancement direction or retreat direction of the positioning pin, the positioning pin is advanced to the pin advance position, and the columnar portion of the positioning pin is fitted into the positioning hole of the insert member in a preparation state, and the injection of resin into the cavity is started in this preparation state, and then, before the injection of resin into the cavity is completed, the positioning pin is retreated to the pin retreat position, so that the entire columnar portion of the positioning pin is released from the positioning hole of the insert member, and the slide block is retreated to the block retreat position, so that it is separated from the insert member, and the space formed by the retreat of the positioning pin and the slide block can also be filled with resin. Therefore, the positional accuracy of the insert member in the resin molded product can be improved. In addition, the positioning hole of the insert member and the abutment portion between the slide block in the preparation state of the insert member can be covered with resin. [Brief description of the drawings]

[0025] [Figure 1]FIG. 1 is an exploded perspective view of a vehicle back door having an inner panel as a resin molded product injection-molded by the injection molding method according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 13 is a perspective view of the right insert member. [Figure 4] FIG. 2 is a molding process diagram showing a preparatory state in the injection molding method according to the first embodiment of the present invention. [Diagram 5] FIG. 2 is a molding process diagram showing a state in which a resin is injected and filled into a cavity in the injection molding method according to the first embodiment of the present invention. [Figure 6] FIG. 2 is a molding process diagram showing a state immediately before an inner panel is released from a movable mold in the injection molding method according to the first embodiment of the present invention. [Figure 7] 2 is a perspective view of a pair of slide blocks, a pair of positioning pins, and a pair of cam members. FIG. [Figure 8] FIG. 10 is a view corresponding to FIG. 1 of the second embodiment. [Figure 9] FIG. 4 is a view equivalent to FIG. 2 of the second embodiment. [Figure 10] FIG. 5 is a view equivalent to FIG. 4 of the second embodiment. [Figure 11] FIG. 7 is a view equivalent to FIG. 5 of the second embodiment. [Figure 12] FIG. 11 is a perspective view of a cam member according to a second embodiment. [Figure 13] FIG. 11 is a perspective view of a plate-shaped member as a resin molded product injection-molded by an injection molding method according to a third embodiment of the present invention. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. [Figure 15] FIG. 5 is a view equivalent to FIG. 4 of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] (Embodiment 1) FIG. 1 shows a vehicle back door 1 of the vertical opening / closing type for opening and closing a door opening provided at the rear end of the body of a hatchback vehicle.

[0028] The back door 1 includes an inner panel 3 as a resin molded product located on the inside of the vehicle, an outer panel 5 made of resin located on the outside of the vehicle, and a window panel (not shown).

[0029] The inner panel 3 has a substantially plate-shaped plate portion 7 facing the outer panel 5. A substantially rectangular window opening 9 extending in the vehicle width direction is formed in the upper half of the plate portion 7. An outer peripheral wall portion 11 rising toward the outer panel 5 is provided in an annular shape around the entire circumference on the outer peripheral edge of the plate portion 7 of the inner panel 3. As shown in FIG. 2, a pair of conical recesses 10 that gradually narrow toward the opposite opening side are formed at intervals in the rising direction of the outer peripheral wall portion 11 at a location near the upper end of the inner peripheral surface of the outer peripheral wall portion 11 on both sides in the vehicle width direction and at a location approximately in the center in the up-down direction. An opening side peripheral wall portion 13 rising toward the outer panel 5 is provided in an annular shape around the entire circumference on the opening 9 side edge of the plate portion 7.

[0030] An insert member 15 made of steel, as shown in FIG. 3, is integrally inserted into both ends of the upper half of the inner panel 3 in the vehicle width direction. The insert member 15 has a plate-shaped main plate portion 17 with a plate surface facing in the plate thickness direction of the plate portion 7 of the inner panel 3. The main plate portion 17 is formed in a substantially V-shape in a plan view by a first plate portion 17a extending along the upper edge of the opening 9, a second plate portion 17b extending from an outer end of the first plate portion 17a in the vehicle width direction toward the outer side in the vehicle width direction at an inclination downward, and a third plate portion 17c extending downward from a lower end (an outer end in the vehicle width direction) of the second plate portion 17b. A protruding plate portion 19 with a plate surface facing in the vehicle width direction is provided on the outer edge of the third plate portion 17c of the main plate portion 17 in the vehicle width direction toward the outer panel 5. A pair of positioning holes 20 each having a circular cross section are formed near the upper end and the lower end of the protruding plate portion 19 at a distance from each other in the protruding direction of the protruding plate portion 19. The entirety of each insert member 15 is embedded in the inner panel 3, and the positioning holes 20 of the insert member 15 are located at positions corresponding to the recesses 10 of the plate portion 7.

[0031] 4 to 6 show a method for injection molding the inner panel 3 configured as described above, as a method for injection molding a resin molded product according to the first embodiment of the present invention.

[0032] For molding, an injection molding die 100 as shown in Figures 4 and 5 and the insert member 15 are prepared. The injection molding die 100 includes a fixed die 101 as a second molding die, and a movable die 103 as a first molding die.

[0033] The fixed mold 101 has a fixed mold first molding surface 101a which molds the surface of the plate portion 7 of the inner panel 3 on the side opposite to the outer panel 5, and a fixed mold second molding surface 101b which molds the outer peripheral surface of the outer peripheral wall portion 11. The fixed mold first molding surface 101a faces substantially vertically downward, while the fixed mold second molding surface 101b faces substantially horizontally.

[0034] The movable mold 103 has a movable mold first molding surface 103a which molds the surface of the plate portion 7 of the inner panel 3 facing the outer panel 5, a movable mold second molding surface 103b which molds the inner peripheral surface of the outer peripheral wall portion 11, and a movable mold third molding surface 103c which molds the end surface of the outer peripheral wall portion 11 (the end surface facing the outer panel 5). The movable mold first molding surface 103a and the movable mold third molding surface 103c face substantially vertically upward. On the other hand, the movable mold second molding surface 103b faces substantially horizontally.

[0035] The movable mold 103 comprises a movable mold main body 105, four slide blocks 107 (only two are shown in Figures 4 to 6), a plurality of first springs 109 as block biasing means, four positioning pins 111, a plurality of second springs 113 as pin biasing means, and four cam members 115.

[0036] The movable mold main body 105 has a main body molding surface 105a which constitutes a part of the movable mold side second molding surface 103b. Four block fitting holes 105b having a circular cross section are formed through the main body molding surface 105a.

[0037] Each slide block 107 has a cylindrical block body 107a. The block body 107a is fitted into the block fitting hole 105b of the movable mold body 105 with its longitudinal direction facing the penetrating direction of the block fitting hole 105b. The slide block 107 can move between a block advance position where it protrudes from the movable mold side second molding surface 103b as shown in FIG. 4 and a block retreat position where it retreats in the opposite protrusion direction from the block advance position as shown in FIG. 5 and FIG. 6. A pin insertion hole 107b having a circular cross section is formed through the block body 107a of the slide block 107 in the advancing and retreating direction of the slide block 107. A ring-shaped protrusion 107c is formed on the outer peripheral surface near the opposite protrusion end of the block body 107a and faces the movable mold body 105 from the retreating direction of the slide block 107.

[0038] The first spring 109 is compressed between the movable mold main body 105 and the protruding portion 107c of the slide block 107 and biases the slide block 107 in the backward direction.

[0039] Each positioning pin 111 can be advanced and retreated to a pin advanced position where it protrudes from the movable mold side second molding surface 103b as shown in FIG. 4, a pin retreated position where it retreats in the direction opposite to the pin advanced position as shown in FIG. 5, and a non-protruding position where it retreats further from the pin retreated position as shown in FIG. 6 and does not protrude from the movable mold side second molding surface 103b. Therefore, the slide block 107 and the positioning pin 111 can be advanced and retreated in a common advanced direction and a common retreated direction. The positioning pin 111 has a columnar portion 111a having a cylindrical shape, and the columnar portion 111a is inserted into the pin insertion hole 107b with its longitudinal direction facing the insertion direction of the pin insertion hole 107b of the slide block 107. On the protruding side of the columnar portion 111a, a tapered portion 111b that gradually becomes thinner toward the protruding direction is formed continuously with the columnar portion 111a to constitute the protruding side end of the positioning pin 111. An annular protruding portion 111c is formed on the outer circumferential surface of the columnar portion 111a of the positioning pin 111 near the end on the opposite side to the protruding side, and faces the slide block 107 from the retracting direction of the positioning pin 111.

[0040] The second spring 113 is compressed between the slide block 107 and the protruding portion 111c of the positioning pin 111 and biases the positioning pin 111 in the backward direction.

[0041] 7, each cam member 115 is formed in a substantially rectangular plate shape with a plate surface facing horizontally, and one surface of the cam member 115 is brought into contact with the positioning pin 111 and the slide block 107 from the retreating direction of the positioning pin 111 and the slide block 107. On the contact surface of the cam member 115 with the positioning pin 111 and the slide block 107, a first surface portion 115a and a second surface portion 115b located in the retreating direction of the positioning pin 111 and the slide block 107 from the first surface portion 115a are formed in order from one side of the longitudinal direction of the cam member 115 (the orthogonal direction substantially perpendicular to the penetrating direction of the pin insertion hole 107b) to be spaced apart from each other. A groove portion 115c extending in the longitudinal direction of the cam member 115 (the orthogonal direction substantially perpendicular to the penetrating direction of the pin insertion hole 107b) is formed on the second surface portion 115b. Between the first surface 115a and the second surface 115b and the bottom surface of the groove 115c, a first inclined surface 115d is formed, which is inclined in the retreat direction of the positioning pin 111 and the slide block 107 toward the other side of the longitudinal direction (the orthogonal direction substantially perpendicular to the penetrating direction of the pin insertion hole 107b) of the cam member 115. In addition, on the bottom surface of the groove 115c, a third surface 115e and a fourth surface 115f located in the retreat direction of the positioning pin 111 and the slide block 107 from the third surface 115e are formed in order from one side of the longitudinal direction (the orthogonal direction substantially perpendicular to the penetrating direction of the pin insertion hole 107b) of the cam member 115, spaced apart from each other. Between the third surface portion 115e and the fourth surface portion 115f, a second inclined surface portion 115g is formed which is inclined from the third surface portion 115e toward the fourth surface portion 115f in the retracting direction of the positioning pin 111 and the slide block 107.

[0042] Each cam member 115 is slidable to a first slide position shown in FIG. 4, a second slide position shown in FIG. 5, and a third slide position shown in FIG. 6 by being driven by a driving device (not shown).

[0043] 4, the cam member 115, at the first slide position, brings the first surface portion 115a into contact with the positioning pin 111 and the slide block 107, and advances the positioning pin 111 to the pin advanced position against the biasing force of the second spring 113, and advances the slide block 107 to the block advanced position against the biasing force of the first spring 109. Also, at the second slide position, the cam member 115 brings the third surface portion 115e on the bottom surface of the groove portion 115c into contact with the positioning pin 111, and advances the positioning pin 111 to the pin retracted position, and brings the groove portion 115c non-forming region of the second surface portion 115b into contact with the slide block 107, and advances the slide block 107 to the block retracted position, as shown in FIG. Furthermore, as shown in FIG. 6, in the third slide position, the cam member 115 abuts the fourth surface portion 115f of the groove portion 115c against the positioning pin 111 while keeping the non-forming area of ​​the groove portion 115c of the second surface portion 115b abutting against the slide block 107, thereby retracting the positioning pin 111 to the non-protruding position.

[0044] Then, the movable die 103 is lowered to open the injection molding die 100, and the cam member 115 is placed at the first slide position, whereby the slide block 107 is advanced to the block advanced position against the biasing force of the first spring 109, and the positioning pin 111 is advanced to the pin advanced position against the biasing force of the second spring 113. In this state, as shown in FIG. 4, the positioning pin 111 is inserted into the positioning hole 20 of the insert member 15, whereby the columnar portion 111a of the positioning pin 111 is fitted into the positioning hole 20 of the insert member 15, and the protruding side end face of the block main body portion 107a of the slide block 107 is brought into contact with the protruding plate portion 19 around the positioning hole 20 of the insert member 15 from the retreating direction of the positioning pin 111. This allows the insert member 15 to be positioned relative to the movable die 103 in the advancing / retracting direction of the positioning pin 111 and in the direction perpendicular to the protruding direction of the positioning pin 111. In this case, since the protruding end of the positioning pin 111 has a tapered portion 111b which gradually becomes narrower in the protruding direction, the positioning pin 111 can be easily inserted into the positioning hole 20 of the insert member 15 compared to when the protruding end face of the positioning pin 111 is made into a flat surface of the same size and shape as the opening of the positioning hole 20 of the insert member 15.

[0045] Next, in a state where the insert member 15 is positioned relative to the movable die 103 as described above, the movable die 103 is raised and the injection molding die 100 is clamped, so that a cavity C is formed between the fixed die 101 and the movable die 103 and the insert member 15, as shown in FIG. 4. In this preparation state, the tip of the positioning pin 111, i.e., the tapered portion 111b, and the fixed die side second molding surface 101b of the fixed die 101 are spaced apart by a distance D. Then, in this preparation state, the injection of the resin R into the cavity C is started. At this time, with the columnar portion 111a of the positioning pin 111 fitted into the positioning hole 20 of the insert member 15, the insert member 15 is restricted from moving in a direction perpendicular to the protruding direction of the positioning pin 111, so that the positional accuracy of the insert member 15 in the inner panel 3 can be improved.

[0046] Thereafter, the cam member 115 is slid toward the second slide position by the driving device until the injection of the resin R into the cavity C is completed. As a result, the positioning pin 111 and the slide block 107 gradually retract while being in sliding contact with the first inclined surface portion 115d of the cam member 115. When the cam member 115 is slid to the second slide position, the positioning pin 111 retracts to the pin retracted position, and the slide block 107 retracts to the block retracted position. At the pin retracted position, the positioning pin 111 causes the entire columnar portion 111a to be released from the positioning hole 20 of the insert member 15, and causes the entire tapered portion 111b to protrude from the movable-mold-side second molding surface 103b of the movable mold 103. Furthermore, with the slide block 107 retracted to the block retracted position, the slide block 107 is separated from the insert member 15, and the protruding end face of the block main body portion 107a of the slide block 107 is flush with the main body molding surface 105a of the movable mold main body portion 105. The timing for sliding the cam member 115 to the second slide position is the timing at which the resin R has been injected into the cavity C to such an extent that the insert member 15 does not move in a direction perpendicular to the protruding direction of the positioning pin 111 even when the columnar portion 111a of the positioning pin 111 is released from the positioning hole 20 of the insert member 15, and the insert member 15 does not move in the retracting direction of the positioning pin 111 even when the slide block 107 is separated from the insert member 15. Then, by continuing to inject resin R into cavity C, resin R is injected to fill the entire cavity C, including space S1 formed by the retraction of positioning pin 111 and space S2 formed by the retraction of slide block 107, and the injection of resin R into cavity C is completed.

[0047] In this way, the resin R is also filled into the space S1 formed by the retreat of the positioning pin 111, so that the portion of the inner panel 3 corresponding to the positioning pin 111 can be made thicker even when the protruding end of the positioning pin 111 approaches the fixed-mold-side second molding surface 101b of the fixed mold 101 in the preparation state. This makes it possible to prevent the inner panel 3 from having sink marks, uneven gloss, and holes due to the portion of the inner panel 3 corresponding to the positioning pin 111 being too thin.

[0048] In addition, the positioning pin 111 is retracted to remove the entire columnar portion 111a from the positioning hole 20 of the insert member 15, and the space S1 formed by the retraction of the positioning pin 111 is also filled with resin R, so that the positioning hole 20 of the insert member 15 can be covered with resin R.

[0049] In addition, by retracting the slide block 107, it is separated from the insert member 15, and the space S2 formed by the retraction of the slide block 107 is also filled with resin R2, so that the contact point between the insert member 15 and the slide block 107 in the preparatory state can be covered with resin R.

[0050] Furthermore, compared to when the tapered portion 111b of the positioning pin 111 is retracted further than the second molding surface 103b on the movable mold side of the movable mold 103 in the retracted position, no protrusions are formed by the resin R filled in the space S1, and the amount of resin R used can be reduced, thereby keeping material costs down.

[0051] In this manner, with the positioning pin 111 retracted to the pin retracted position and the slide block 107 retracted to the block retracted position, the resin R hardens and the inner panel 3 with the insert member 15 inserted therein is molded. At this time, the tapered portion 111b of the positioning pin 111 engages with the recess 10 of the inner panel 3, thereby preventing the inner panel 3 from being released from the mold. In other words, the recess 10 of the inner panel 3 forms an undercut portion that cannot be removed from the movable mold 103.

[0052] Thereafter, the movable mold 103 is lowered to open the mold, and the cam member 115 is slid from the second slide position to the third slide position as shown in Fig. 6, thereby further retracting the positioning pin 111 to a non-protruding position where it does not protrude from the movable-mold-side second molding surface 103b of the movable mold 103, thereby enabling the inner panel 3 to be released. Then, in this state, the inner panel 3 is removed upward from the movable mold 103 (in the direction shown by the arrow X in Fig. 6).

[0053] In this way, the positioning pin 111 is retracted to a non-protruding position before the inner panel 3 is released, so that the position of the positioning pin 111 at the end of injection of the resin R into the cavity C can be set to a position that prevents the inner panel 3 from being released, thereby increasing the freedom of shape of the inner panel 3.

[0054] Therefore, according to the first embodiment, the positioning pin 111 and the slide block 107 are advanced and retreated by the sliding action of the cam member 115, so that the movable mold 103 can be made smaller and equipment costs can be reduced compared to the case where they are advanced and retreated by a hydraulic system.

[0055] Also, since the tapered portion 111b of the positioning pin 111 does not come into contact with the fixed-mold-side second molding surface 101b of the fixed mold 101 in the preparation state and the fixed-mold-side second molding surface 101b of the fixed mold 101 is not damaged by the tapered portion 111b of the positioning pin 111, it is possible to provide irregularities on the fixed-mold-side second molding surface 101b and use the irregularities to form a grain pattern on the surface of the inner panel 3 (the surface opposite the outer panel 5). This increases the degree of freedom in designing the inner panel 3.

[0056] (Embodiment 2) Fig. 8 is a view corresponding to Fig. 1 of embodiment 2. In the inner panel 3 injection molded by the injection molding method according to embodiment 2, four recesses 10 are formed at each end in the vehicle width direction of the upper half of the plate portion 7 at intervals in the direction along the outer circumferential edge of the plate portion 7, as also shown in Fig. 9.

[0057] Further, no protruding plate portion 19 is formed on the insert member 15. An outer peripheral side wall portion 21 is provided on the outer peripheral edge of the main plate portion 17 of the insert member 15 and protrudes toward the outer panel 5, and an inner peripheral side wall portion 23 is provided on the inner peripheral edge of the main plate portion 17 and protrudes toward the outer panel 5. Four positioning holes 20 are formed in each insert member 15 and spaced apart from each other in the extension direction of the main plate portion 17.

[0058] 10, in the injection molding die 100 used in the injection molding method according to the second embodiment, the body part molding surface 105a of the movable mold body part 105 constitutes a part of the movable mold side first molding surface 103a. Each slide block 107 can advance and retreat between a block advance position where the block body part 107a is protruded at the movable mold side first molding surface 103a, and a block retreat position where the block advance position is retreated in the counter-protruding direction as shown in FIG.

[0059] In addition, each positioning pin 111 can be advanced or retreated between a pin advanced position where it protrudes from the first molding surface 103a on the movable mold side as shown in Figure 10, and a pin retracted position where it retracts in the opposite protruding direction from the pin advanced position as shown in Figure 11.

[0060] 12, the fourth surface portion 115f and the second inclined surface portion 115g are not formed on the cam member 115. The cam member 115 is slidable to a first slide position shown in FIG 10 and a second slide position shown in FIG 11.

[0061] In this embodiment 2, when the positioning pin 111 is positioned in the pin retracted position, the tapered portion 111b of the positioning pin 111 does not hinder the release of the inner panel 3, so the positioning pin 111 is not retracted to a non-protruding position where it does not protrude from the first molding surface 103a on the movable mold side of the movable mold 103 before the inner panel 3 is released.

[0062] The rest of the injection molding die 100 and injection molding method for the inner panel 3 are similar to those in the first embodiment, so the same components are given the same reference numerals and detailed description thereof will be omitted.

[0063] (Embodiment 3) 13 and 14 show a plate-shaped member 25 as a rectangular plate-shaped resin molded product injection molded by the injection molding method according to the third embodiment of the present invention. The front surface of this plate-shaped member 25 (the lower surface in Figs. 13 and 14) is formed flat. Meanwhile, a quadrangular pyramid-shaped recess 10 that gradually narrows toward the opposite side is formed in the center of the back surface of the plate-shaped member 25.

[0064] An insert member 15 made of iron and shaped like a rectangular plate is integrally inserted into the plate-like member 25. A positioning hole 20 having a square (rectangular) cross section is formed penetrating the center of the insert member 15.

[0065] FIG. 15 shows a preparation state in an injection molding method for a resin molded product according to the third embodiment of the present invention.

[0066] The fixed mold 101 has a fixed mold side surface molding surface 101c which molds the surface of the plate-like member 25, and a fixed mold side end surface molding surface 101d which molds approximately half of the surface side of the outer peripheral end surface of the plate-like member 25. The fixed mold side surface molding surface 101c faces approximately vertically downward, while the fixed mold side end surface molding surface 101d faces approximately horizontally.

[0067] The movable mold 103 has a movable mold-side back surface molding surface 103d which molds the back surface of the plate-like member 25, and a movable mold-side end surface molding surface 103e which molds approximately half of the back surface area of ​​the outer peripheral end surface of the plate-like member 25. The movable mold-side back surface molding surface 103d faces approximately vertically upward. On the other hand, the movable mold-side end surface molding surface 103e faces approximately horizontally.

[0068] In this embodiment 3, the body part molding surface 105a of the movable mold body part 105 constitutes a part of the movable mold side back surface molding surface 103d. The movable mold 103 is provided with only one slide block 107, which can advance and retreat between a block advance position where the block body part 107a protrudes on the movable mold side back surface molding surface 103d and a block retreat position where the slide block 107 retreats in the opposite protruding direction from the block advance position, as shown in Fig. 15.

[0069] In addition, the movable mold 103 is also provided with only one positioning pin 111, which can be advanced and retreated between a pin advanced position where it protrudes from the first molding surface 103a of the movable mold side and a pin retracted position where it retracts in the opposite protruding direction from the pin advanced position as shown in Figure 15.

[0070] The columnar portion 111a of the positioning pin 111 is formed in a quadrangular column shape, and the tapered portion 111b is formed in a quadrangular pyramid shape. The pin insertion hole 107b of the slide block 107 is also formed in a rectangular cross section.

[0071] Further, the movable mold 103 is provided with only one cam member 115 .

[0072] The rest of the injection molding die 100 and the injection molding method for the plate-like member 25 are similar to those in the second embodiment, so the same components are given the same reference numerals and detailed description thereof will be omitted.

[0073] Therefore, according to the third embodiment, since the positioning hole 20 of the insert member 15 has a rectangular cross section and the columnar portion 111a of the positioning pin 111 has a quadrangular column shape, the positioning pin 111 restricts the rotation of the insert member 15 around the positioning pin 111 in the preparation state. Therefore, the positional accuracy of the insert member 15 in the inner panel 3 can be improved.

[0074] In the above first and second embodiments, the insert member 15 is made of iron, but it may be made of other metals such as aluminum or brass.

[0075] In the above-mentioned first and second embodiments, the columnar portion 111a of the positioning pin 111 is cylindrical and the tapered portion 111b is conical, but the columnar portion 111a may be rectangular columnar and the tapered portion 111b may be rectangular pyramid. In the above-mentioned first to third embodiments, the cross section of the columnar portion 111a may be a shape other than a circle or a square.

[0076] In addition, in the above-mentioned embodiments 1 to 3, the tapered portion 111b of the positioning pin 111 may have a shape other than a cone. For example, the tapered portion 111b of the positioning pin 111 may have a truncated cone shape such as a circular truncated cone or a pyramid, or may have a curved shape that gradually narrows toward the tip.

[0077] In addition, in the above-mentioned first to third embodiments, the positioning hole 20 of the insert member 15 has a circular or rectangular cross section, but may have other shapes as long as the shape allows the columnar portion 111a of the positioning pin 111 to fit therewith.

[0078] Furthermore, in the above-mentioned first to third embodiments, the positioning hole 20 of the insert member 15 is a through hole, but it may be a hole with a bottom.

[0079] Furthermore, in the above-mentioned first to third embodiments, the slide block 107 is provided on the movable mold 103, but it may be provided on the fixed mold 101.

[0080] In addition, in the above-mentioned first to third embodiments, the positioning pin 111 is provided on the movable mold 103, but it may be provided on the fixed mold 101.

[0081] In addition, in the above-mentioned first to third embodiments, the slide block 107 is brought into contact with the insert member 15 in the preparation state from the retreating direction of the positioning pin 111, but it may be brought into contact from the advancing direction. [Industrial Applicability]

[0082] The present invention is useful as an injection molding method and an injection molding die for molding a resin molded product into which an insert member is inserted by injecting and filling a cavity formed between a first molding die, a second molding die, and an insert member. [Explanation of symbols]

[0083] 3 Inner panel (plastic molded product) 10 Recess 15 Insert material 20 Positioning hole 25 Plate-shaped components (plastic molded products) 100 Injection mould 101 Fixed mold (second mold) 101b Fixed mold side second molding surface 101c Molded surface for fixed mold side surface 103 Movable mold (1st mold) 103a First molding surface on movable mold side 103b Second molding surface on movable mold side 103d Molding surface for side and back side of movable mold 107 Slide Block 107b Pin insertion hole 109 First spring (block biasing means) 111 Locating pin 111a Columnar part 111b Tapered section 113 Second spring (pin biasing means) 115 Cam member 115a First side 115b Second side part 115c Groove 115d 1st slope section C Cavity D interval S1,S2 space

Claims

1. An injection molding method for molding a resin molded product (3, 25) into which an insert member (15) is inserted by injecting and filling a resin (R) into a cavity (C) formed between a first molding die (103) and a second molding die (101) and an insert member (15), comprising: One of the first molding die (103) and the second molding die (101) is provided with a slide block (107) that can move between a block advance position where the slide block protrudes from a molding surface (103a, 103b, 103d) of the one of the molding dies (103) and a block retract position where the slide block retracts in a direction opposite to the block advance position; The first mold (103) is provided with a positioning pin (111) having a columnar portion (111a) and capable of moving between a pin advanced position where the pin advanced position protrudes from a molding surface (103a, 103b, 103d) of the first mold (103) and a pin retracted position where the pin advanced position retracts in a direction opposite to the protruding direction, The insert member (15) is formed with a positioning hole (20), the slide block (107) is advanced to the block advanced position, the slide block (107) is brought into contact with the insert member (15) from the advancing or retracting direction of the positioning pin (111), the positioning pin (111) is advanced to the pin advanced position, the columnar portion (111a) of the positioning pin (111) is fitted into the positioning hole (20) of the insert member (15), and in the preparatory state in which the first molding die (103) and the second molding die (101) are clamped, injection of resin (R) into the cavity (C) is started; Thereafter, before the injection of resin (R) into the cavity (C) is completed, the positioning pin (111) is retracted to the pin retracted position to remove the entire columnar portion (111a) of the positioning pin (111) from the positioning hole (20) of the insert member (15), and the slide block (107) is retracted to the block retracted position to separate it from the insert member (15), and the resin (R) is also filled into the spaces (S1, S2) formed by the retraction of the positioning pin and the slide block (107).

2. The method for injection molding a resin molded product according to claim 1, The one mold is the first mold (103), A pin insertion hole (107b) is formed through the slide block (107) in the forward and backward direction of the slide block (107), The positioning pin (111) is inserted into the pin insertion hole (107b) of the slide block (107), The slide block (107) and the positioning pin (111) can advance and retreat in a common forward direction and a common backward direction, The first mold (103) is further provided with a pin biasing means (113) for biasing the positioning pin (111) in the common backward direction, a block biasing means (109) for biasing the slide block (107) in the common backward direction, and a cam member (115) for contacting the positioning pin (111) and the slide block (107) from the common backward direction, A first surface portion (115a) and a second surface portion (115b) positioned in the common retreat direction from the first surface portion (115a) of the cam member (115) are formed on a contact surface between the positioning pin (111) and the slide block (107) in order from one side in an orthogonal direction substantially perpendicular to the penetration direction of the pin insertion hole (107b) to be spaced apart from each other, and a groove portion (115c) extending in the orthogonal direction is formed on the second surface portion (115b), and an inclined surface portion (115d) inclined in the common retreat direction toward the other side of the orthogonal direction is formed between the first surface portion (115a) and the second surface portion (115b) and a bottom surface of the groove portion (115c); the cam member (115) is slidable between a first slide position at which the first surface portion (115a) is brought into contact with the positioning pin (111) and the slide block (107), causing the positioning pin (111) to advance to the pin advanced position against the biasing force (113) of the pin biasing means, and causing the slide block (107) to advance to the block advanced position against the biasing force of the block biasing means (109); and a second slide position at which the bottom surface of the groove portion (115c) is brought into contact with the positioning pin (111), causing the positioning pin (111) to retract to the pin retracted position, and a region of the second surface portion (115b) where the groove portion (115c) is not formed is brought into contact with the slide block (107), causing the slide block (107) to retract to the block retracted position, In the preparation state, the cam member (115) is disposed at the first slide position, a cam member (115) being slid from the first slide position to the second slide position between the start and end of injection of resin (R) into the cavity (C).

3. The method for injection molding a resin molded product according to claim 1 or 2, a tapered portion (111b) that gradually narrows in the protruding direction is formed at the protruding end of the positioning pin (111) and is continuous with the columnar portion (111a).

4. The method for injection molding a resin molded product according to claim 3, a tapered portion (111b) of the positioning pin (111) and a molding surface (101a, 101b, 101c) of the second mold (101) are spaced apart by a distance (D) in the preparation state.

5. The method for injection molding a resin molded product according to claim 3 or 4, a tapered portion (111b) of the positioning pin (111) protruding entirely from the molding surface (103a, 103b, 103d) of the first mold (103) when the positioning pin (111) is in the retracted position;

6. The method for injection molding a resin molded product according to any one of claims 1 to 5, A recess (10) is formed in the resin molded product (3), a recess (10) of the resin molded product (3) that engages with the recess (10) of the resin molded product (3) to prevent the resin molded product (3) from being released, to a non-protruding position where the positioning pin (111) does not protrude from the molding surface (103a, 103b, 103d) of the first mold (103) before the resin molded product (3) is released, thereby enabling the resin molded product (3) to be released.

7. An injection molding die includes a first molding die (103) and a second molding die (101), and molds a resin molded product (3, 25) into which the insert member (15) is inserted by injecting and filling a resin (R) into a cavity (C) formed between the first molding die (103) and the second molding die (101) and an insert member (15), One of the first molding die (103) and the second molding die (101) is provided with a slide block (107) that can move between a block advance position where the slide block protrudes from a molding surface (103a, 103b, 103d) of the one of the molding dies (103) and a block retract position where the slide block retracts in a direction opposite to the block advance position; The injection molding die is characterized in that the first mold (103) is provided with a positioning pin (111) having a columnar portion (111a) and capable of advancing and retreating between a pin advance position where the pin protrudes from the molding surface of the first mold (103) and a pin retract position where the pin retracts in the opposite direction from the pin advance position.

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