JP2006182158A - Airbag cover molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag cover molding method capable of realizing smooth flow of a molding material during the molding and preventing generation of dents or the like to degrade the design property. <P>SOLUTION: During the molding, a molding material M is poured in a part of a breakage scheduled part 16b on the back side of an airbag cover along the direction orthogonal to the arrangement direction of the breakage scheduled part 16b, and a shape-forming recessed part 40 of a continuous side shape-giving part 37 and a recessed part 47 of a connection side shape-forming part 44 are juxtaposed to each other along the pouring direction of the molding material M to pass the molding material M. After the pouring, the connection side shape-giving part 44 is moved to form a connection groove part 24 while a shape-giving projection part 45 of the connection side shape-giving part 44 is arranged between shape-giving projecting parts 38, 38 of the connection side shape-giving part 37, and a molded airbag cover is released and manufactured. When the breakage scheduled part 16b is pressed by an airbag and broken, a thin-walled part to connect a thin-walled part 20 formed of the shape-giving projecting part 38 to the connection groove 24 is broken. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a synthetic resin airbag cover that covers a folded airbag and is pushed by an airbag when inflated to break a thinly-scheduled breakage portion to form an opening for the airbag to protrude. The present invention relates to a molding method.

  Conventionally, in an air bag cover made of synthetic resin, when the air bag is pushed, a door portion is opened to form a protruding opening, so that a thin breakage planned portion is formed around the door portion. (For example, refer to Patent Document 1). The breakage portion is configured by providing a recess along the breakage portion on the back surface side of the airbag cover, and a projection corresponding to the recess is formed on the mold surface of the mold for molding the airbag cover. Was formed.

If the protrusion protrudes into the cavity in the mold-closed state in advance, the flow of the molding material is deteriorated and molding is liable to occur. Therefore, when the molding material is injected, the protrusion is pulled. In other words, the protrusion was projected into the cavity after the injection to form a recess for the portion to be broken.
Japanese Patent Laid-Open No. 2002-234413 (pages 5-7, FIG. 1)

  However, in the conventional molding method, after the injection of the molding material, from the back side of the airbag cover to the surface side, the projection for forming the planned fracture portion is pressed, so the surface side of the airbag cover, that is, There is a possibility that indentation or the like is generated on the design surface side of the airbag cover, thereby reducing the design property.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and a method for molding an airbag cover that can be produced while smoothing the flow of the molding material at the time of molding and preventing the occurrence of indentations or the like that lower the designability. The purpose is to provide.

A method for forming an airbag cover according to the present invention covers a folded airbag and is pushed by the airbag when inflated to break a thinly-scheduled breakage portion to form an opening for projecting the airbag. A method of molding a synthetic resin airbag cover,
The part to be broken is
While formed by a recess provided on the back side of the airbag cover along the planned breakage portion,
A continuous concavo-convex portion formed by alternately and continuously providing a thin portion and a thick portion disposed on one edge side in a direction orthogonal to the disposition direction of the planned break portion in the planned break portion;
It is arranged on the other edge side in the direction orthogonal to the arrangement direction of the planned breaking part in the planned breaking part, and is arranged so as to connect adjacent thin parts of the continuous uneven part, and more thick than the thick part. A connecting portion having a thinned connecting groove;
Configured with
The mold side of the molding die at the portion of the back surface of the airbag cover that has a portion to be broken has a shaping convex portion and a shaping concave portion that can form a thin portion and a thick portion of the continuous uneven portion. It has a shaping part, a shaping projection part that can form a coupling groove part of the coupling part, and a depression part that is arranged between the shaping projection parts and has a shaping concave part and an equal height, along the part to be broken And a movable side shaping part movable,
At the time of molding, the molding material is injected along the direction perpendicular to the arrangement direction of the planned breaking portion at the portion of the planned breaking portion on the back surface side of the airbag cover, and continuous side shaping is performed along the injection direction of the molding material. The molding concave portion of the part and the concave portion of the connecting side shaping portion are arranged side by side, and the molding material is passed through,
After injection, the connecting side shaped part was moved to form the connecting groove part while arranging the shaping projections of the connecting side shaped part between the shaping convex parts of the continuous side shaped part, and then molded The air bag cover is released from the mold.

  In the method for molding an airbag cover according to the present invention, when injecting the molding material at the time of molding, the shaping concave portion of the continuous side shaping portion and the shaping at the connection side shaping portion are arranged along the injection direction of the molding material. A recess and a recess having the same height are juxtaposed. Therefore, the molding material injected at the time of molding is the portion of the continuous side shaping portion from the upstream side to the downstream side of the molding material with the site of the planned fracture portion at the site of the planned fracture portion on the back side of the airbag cover. It is possible to prevent the filling failure of the molding material from flowing smoothly through the material flow path without any interference formed by arranging the shaping concave portion and the depression portion of the coupling side shaping portion side by side. it can.

  After that, when the molding material starts to solidify, the connecting side shaped part is moved, and the connecting groove is formed while the forming projections of the connecting side shaped part are arranged between the forming convex parts of the continuous side shaped part. Then, if the molded airbag cover is released, the manufactured airbag cover can be obtained.

  And, at the time of molding of the airbag cover, at the part of the planned breaking part, the connecting side shaping part of the mold moves only along the planned breaking part to the surface side that becomes the design surface side of the airbag cover. Therefore, an indentation or the like that lowers the designability is not generated on the design surface of the airbag cover.

  Therefore, in the method of molding an airbag cover according to the present invention, the flow of the molding material at the time of molding can be smoothed, and the generation of an indentation or the like that lowers the designability can be prevented, and the airbag cover can be manufactured. it can.

  Of course, in the airbag cover manufactured in this way, after forming the connecting groove portion while arranging the forming protrusion of the connecting side forming portion between the forming convex portions of the continuous side forming portion, it is released from the mold. As a recess for forming the planned breakage portion, the thinned portion and the thick wall portion are formed alternately and continuously on one edge side of the planned breakage portion in the direction orthogonal to the disposition direction of the planned breakage portion. And a connecting groove portion disposed on the other edge side in the direction orthogonal to the disposition direction of the planned rupture portion in the planned rupture portion, and arranged to connect adjacent thin portions of the continuous concavo-convex portion. A connecting portion having an air bag, and forming a thin portion where the thin portion of the continuous concavo-convex portion and the connecting groove portion of the connecting portion are continuously connected so as to follow the portion to be broken. When the part to be ruptured is pushed by the, it is connected to the thin part of the continuous uneven part Thin thickness portion continuing the connecting groove portion of, and smoothly break, will form the projection opening of the airbag.

  Then, the shaping convex part of the continuous side shaping part and the shaping projection part of the connection side shaping part are formed so that the opposing surfaces are mutually slidable planes, and the shaping projection part is connected The shaping projections of the side shaping part are arranged between the shaping convex parts of the continuous side shaping part, and the edge side of the shaping convex part side of the continuous side shaping part is attached to the airbag cover. As a cross-sectional shape along the back surface, it is desirable to form an acute angle.

  In such a configuration, even when the molding material is hard and solid, it is formed in an acute angle shape when moving the molding protrusions of the connecting side shaping part between the shaping convex parts of the continuous side shaping part. The formed groove portion cuts into the hardened and solidified molding material and smoothly forms the shaping projections between the shaping convex portions of the continuous side shaping portion to form the connecting groove portion.

  In this case, the edge on the moving direction side formed in an acute angle shape in the shaping projection part is inclined toward the rear side in the movement direction toward the tip side of the shaping projection part, and if it is formed, it is cut during movement. It becomes possible to suppress the resistance, and it becomes easier to cut the hardened and solidified molding material, and the connecting groove portion can be formed smoothly.

The airbag cover according to the present invention covers the folded airbag, and is pushed by the airbag when inflated to break the thin portion to be broken, thereby forming an opening for the airbag to protrude. A resin airbag cover,
The part to be broken is
While formed by a recess provided on the back side of the airbag cover along the planned breakage portion,
A continuous concavo-convex portion formed by alternately and continuously providing a thin portion and a thick portion disposed on one edge side in a direction orthogonal to the disposition direction of the planned break portion in the planned break portion;
It is arranged on the other edge side in the direction orthogonal to the arrangement direction of the planned breaking part in the planned breaking part, and is arranged so as to connect adjacent thin parts of the continuous uneven part, and more thick than the thick part. A connecting portion having a thinned connecting groove;
It is characterized by comprising.

  In the airbag cover according to the present invention, the concave portion forming the planned fracture portion is disposed on one edge side in the direction orthogonal to the direction in which the planned fracture portion is disposed in the planned fracture portion. Connected between adjacent concave and convex portions, which are arranged on the other edge side in the direction orthogonal to the arrangement direction of the planned rupture portion of the planned rupture portion and the continuous concavo-convex portion formed by alternately and continuously providing And a connecting portion having a connecting groove portion arranged so as to be formed, and a thin portion where the thin portion of the continuous uneven portion and the connecting groove portion of the connecting portion are continuously connected along the planned breaking portion. Therefore, when the portion to be ruptured is pushed by the airbag, the thin portion of the continuous uneven portion and the connecting groove portion of the connecting portion are smoothly broken, so that the airbag protrudes. An opening will be formed.

  And in such an airbag cover, the continuous side shaping part which has the shaping convex part and the shaping recessed part which can shape the thin part and thick part of the above-mentioned continuous uneven part, and the connection A molding comprising a shaping projection that can form a coupling groove of the portion and a depression arranged between the shaping projections, and a coupling-side shaping portion that is movable along the planned fracture portion By using a mold, the flow of molding material at the time of injection can be improved, and it is possible to produce with good yield by suppressing the occurrence of defective products without causing indentation on the design surface. It becomes.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An airbag cover 10 manufactured in the embodiment is used for a passenger airbag device S as shown in FIGS. Further, it is made of a synthetic resin manufactured by injection molding from an olefin-based thermoplastic elastomer or the like, and is disposed in the opening 2b on the upper surface 2a side of the instrument panel (hereinafter referred to as instrument panel) 2 in front of the passenger seat.

  In the present specification, the up / down, front / rear, and left / right directions correspond to the up / down, front / rear, and left / right directions of the vehicle in a straight traveling state of the vehicle with the airbag cover 10 mounted as a reference. It is.

  The passenger airbag device S includes a folded airbag 4, an inflator 7 that supplies inflation gas to the airbag 4, a case 8 that stores and holds the airbag 4 and the inflator 7, and the airbag 4. Is provided with a retainer 5 for attaching to the case 8 and an airbag cover 10 that covers the folded airbag 4.

  The airbag 4 has a substantially quadrangular pyramid shape with the front end side as a top portion and the rear surface side of the bottom surface as an occupant restraint portion when the inflation is completed. The airbag 4 is folded and housed on the upper surface 2 side of the instrument panel 1 in front of the passenger seat when mounted on a vehicle, and an unillustrated windshield above the instrument panel upper surface 2a and the instrument panel 2 when inflated gas flows in. In order to close the gap between the two, it protrudes upward and protrudes rearward, and the occupant restraint portion on the rear surface side protects the occupant.

  The inflator 7 includes a substantially cylindrical main body portion 7 a having a plurality of gas discharge ports 7 b and a flange portion 7 c for attaching the inflator 7 to the case 8.

  Further, the case 8 is formed in a substantially rectangular parallelepiped shape made of a sheet metal having a rectangular opening on the upper end side, and a substantially rectangular plate-like bottom wall portion 8a to which the inflator 7 is inserted from below and attached, and the bottom wall portion 8a. And a plurality of locking claws 8c for locking the side wall 28 of the airbag cover 10 are formed at the upper end of the peripheral wall 8b. . The case 8 is provided with a bracket 8d connected to the body 1 side of the vehicle at the bottom wall 8a.

  The airbag 4 and the inflator 7 include a plurality of bolts 5 a of an annular retainer 5 disposed in the airbag 4, a peripheral edge 4 b of the opening 4 a of the airbag 4, a flange portion 7 c of the inflator 7, and The nut 6 is fixed to the case 8 by passing through the case bottom wall portion 8a.

  The airbag cover 10 includes a rectangular plate-shaped ceiling wall portion 11 so as to close the opening 2a of the instrument panel 2, and a substantially rectangular tube-shaped side wall portion 28 extending downward from the lower surface (back surface) side of the ceiling wall portion 11. It is prepared for. A plurality of locking holes 28e for locking the periphery of the locking claws 8c of the case peripheral wall 8b are formed in the front and rear walls 28a and 28b of the side wall 28.

  The ceiling wall portion 11 is configured to include a projecting opening portion 12 disposed at a site surrounded by the side wall portion 28 and a peripheral edge portion 27 around the opening portion 12. A plurality of locking legs 27 a formed on the opening peripheral edge 2 b are provided on the peripheral edge 27 so as to eliminate rattling when the airbag cover 10 is disposed so as to close the opening 2 b of the instrument panel 2. Projected.

  The projecting opening 12 is formed in a rectangular plate shape, and the two front and rear doors 13 and 14 are opened on both the front and rear sides to form a projecting rectangular opening 12a. The door 13 at the time of opening opens to the front side while turning upward, with the hinge portion 15 disposed on the front edge side as the rotation center, and the door 14 at the time of opening, with the hinge portion 15 on the rear edge side as the rotation center, It will open to the rear side while heading upward. The hinge portion 15 is disposed at the position of the inner side surfaces of the wall portions 28 a and 28 b before and after the side wall portion 28.

  As shown in FIGS. 1 to 7, a planned break portion 16 that is pushed by the inflating airbag 4 and breaks is formed around the door portions 13 and 14. The planned fracture portion 16 is configured by providing two types of recesses 16a and 16b on the back surface side of the projecting opening 12, and in the case of the embodiment, in the left-right direction at an intermediate portion in the front-rear direction of the projecting opening 12. A horizontal line-shaped recess 16a that extends and four vertical line-shaped recesses 16b that extend from the left and right ends of the horizontal line-shaped recess 16a to the front and rear sides are provided, and are formed in a substantially H shape when viewed from above. ing. The vertical line-shaped concave portion 16 b is disposed at the position of the inner side surface of the left and right wall portions 28 c and 28 d of the side wall portion 28.

  Moreover, the site | part of the horizontal linear recessed part 16a is a site | part between the door parts 13 * 14, and the uniform thin part 17 made into uniform thickness is formed along the left-right direction, and is comprised.

  In each vertical line-shaped concave portion 16b, a continuous concave-convex portion 19 and a connecting portion 23 that are arranged in parallel along the direction orthogonal to the direction in which the concave portion 16b is disposed are disposed.

  The continuous concavo-convex portion 19 is one edge side in the direction orthogonal to the arrangement direction of the vertical linear recess 16b in the vertical linear recess 16b, and in the case of the embodiment, the left and right wall portions of the side wall portion 28 approaching each other. It is arranged on the 28c / 28d side. And the continuous uneven | corrugated | grooved part 19 is formed by providing the thin part 20 and the thick part 21 alternately continuously along the recessed part 16b. In the case of the embodiment, the continuous uneven portion 19 is formed by continuously providing a concave portion 19a that is recessed in an inverted V shape from the back surface side to the front surface side of the cover 10, the width dimension in the left-right direction is constant, and the front and rear It is formed as a saw blade shape in which the outer shape of the cross section along the direction is constant along the left-right direction.

  The connecting portion 23 is disposed on the other edge side of the vertical linear recess 16b in the direction perpendicular to the direction in which the vertical linear recess 16b is disposed, that is, on the center side of the projecting opening 12. The connecting portion 23 includes a connecting groove portion 24. The connecting groove portion 24 is disposed so as to connect the adjacent thin portions 20 and 20 of the continuous uneven portion 19, and has a thickness (thickness in the thickness direction of the protruding opening 12) from the thick portion 21. It is thin. In the case of the embodiment, the connecting groove portion 24 opens between the thick portion 21 of the continuous concavo-convex portion 19 with the width dimension in the left-right direction narrowed, and a linear groove-like recess portion 23a along the front-rear direction. Is formed on the back side of the protruding opening 12. Further, the connecting portion 23 is formed continuously with a triangular pyramid-shaped concave portion 23b narrowing on the surface side of the protruding opening 12 along the concave portion 16b. These concave portions 23 b are arranged such that the peripheral edge on the continuous uneven portion 19 side coincides with the peripheral edge of the concave portion 19 a of the continuous uneven portion 19. And in the case of embodiment, the groove-shaped recessed part 23a which forms the connection groove part 24 is arrange | positioned so that the bottom part (top part) 23c of the narrowing of each recessed part 23b may be connected along the front-back direction.

  As shown in FIG. 8, a molding die 30 used when the airbag cover 10 is manufactured by injection molding is opened and closed along the vertical direction of the airbag cover 10 to be molded (at the time of actual molding, the horizontal direction It is configured to include two split molds 31 and 32 that open and close along. The split mold 31 includes a mold surface 31 a that molds the front side of the airbag cover 10, and the split mold 32 includes a mold surface 32 a that molds the back side of the airbag cover 10. Further, the split mold 32 includes a main body portion 33 having a mold surface 33a for molding the back surface side of the ceiling wall portion 11 and the side wall portion 28 in portions other than the planned fracture portion 16, and first, second, third and fourth cores 34, 36, 43, and 49.

  As shown in FIGS. 9 to 12, the first core 34 is a part of the horizontal linear recess 16 a of the planned fracture portion 16, i.e., the uniform thin-walled portion 17. Along the uniform thin portion 17 to be molded, it is embedded and fixed in the main body portion 33. The amount of protrusion of the first core 34 from the main body 33 toward the cavity 30a corresponds to the depth of the recess 16a, and the end surface 34a of the first core 34 and the mold surface 31a of the split mold 31 In the meantime, the uniform thin portion 17 is formed.

  8-12, the 2nd core 36 shape | molds the continuous uneven part 19 in the vertical linear recessed part 16b of the fracture | rupture planned part 16, and shape | molds the front end surface side as a substantially rectangular plate shape. Along the continuous concavo-convex portion 19, it is embedded and fixed in the main body portion 33. The continuous side shaping portion 37 that forms the thin portion 20 and the thick portion 21 of the continuous uneven portion 19 between the tip end side protruding from the main body portion 33 toward the cavity 30 a and the mold surface 31 a of the split die 31. It is said. The continuous side shaping portion 37 is formed by alternately forming a shaping convex portion 38 that molds the concave portion 19a on the thin portion 20 side of the continuous concave and convex portion 19 and a shaping concave portion 40 that molds the thick portion 21 side. Configured.

  In the continuous side shaping portion 37 of the embodiment, a shaping convex portion 39 having a half shape of the other shaping convex portion 38 is formed at the terminal on the first core 34 side, and the first middle portion 34 is formed. It is in contact with the child 34.

  As shown in FIGS. 8 to 12, the third core 43 is for forming the connecting portion 23 in the vertical line-shaped concave portion 16 b of the planned breaking portion 16, and is formed in a substantially rectangular plate shape on the tip surface side. It arrange | positions along the connection part 23, and is hold | maintained at the split mold 32 side so that a movement is possible. The movement direction of the third core 43 moves in the direction away from the first core 34 along the arrangement direction of the recess 16b (the front-rear direction in the embodiment) after the molding material M is injected. And the front end side which protrudes from the main-body part 33 of the 3rd core 43 to the cavity 30a side is used as the connection side shaping part 44 which shape | molds the connection part 23 between the mold surfaces 31a of the split mold 31. FIG. The connection side shaping portion 44 includes a shaping projection 45 that can form the coupling groove 24 and a recess 47 that is disposed between the shaping projections 45 and has the same height as the shaping recess 40. Configured.

  In the case of the embodiment, the shaping protrusion 45 has a triangular pyramid shape corresponding to the recess 23 b of the connecting portion 23. The shaping projection 45 and the shaping convex portion 38 of the continuous side shaping portion 37 are formed so that the opposing surfaces 45a and 38a are flat surfaces that can slide on each other.

  In particular, the opposing surfaces 45a and 38a of the embodiment have the same shape (substantially equilateral triangular shape in the embodiment). In the embodiment, the pitch of the shaping protrusions 45 is set to be equal to the pitch of the shaping projections 38 along the front-rear direction, and the opening of the recess 47 along the left-right direction is set. The shape is the same as the opening shape along the left-right direction of the shaping recess 40 (substantially equilateral triangle in the embodiment).

  Further, the shaping protrusion 45 moves from the state before the movement of the third core 43 so as to move the shaping protrusion 45 between the shaping protrusions 38 of the continuous side shaping part 37. That is, on the side away from the first core 34 and the edge 45b side on the shaping convex portion 38 side of the continuous side shaping portion 37 as a cross-sectional shape along the back surface of the airbag cover 10, in an acute angle shape, It is formed. Furthermore, the edge 45d side is formed so as to incline toward the rear side in the moving direction as it goes toward the tip side.

  In the case of the embodiment, the shaping protrusion 45 has a triangular pyramid shape, and gradually decreases the thickness dimension along the direction from the base portion side to the distal end side toward the continuous side shaping portion 37 side. Is formed.

  By the way, in the shaping projection part 45 of the embodiment, the other edge 45d excluding both edges 45b and 45c of the facing surface 45a is formed in a triangular pyramid shape that is arranged on the center side in the left-right direction of the protruding opening 12. The cross section is an isosceles triangle (regular triangle) (see FIG. 11).

  Furthermore, in the case of the embodiment, the gate 30b for injecting the molding material M into the cavity 30a of the mold 30 is the side extended in the left-right direction in the arrangement direction of the horizontal linear recess 16a of the planned fracture portion 16, in the embodiment It is arranged on the left side (see FIGS. 3 and 4). Therefore, if the molding material M is injected from the gate 30b at this position, in the case of the embodiment, the molding material M is substantially along the left-right direction orthogonal to the arrangement direction of the vertical line-shaped recess 16b of the planned fracture portion 16. It will flow from the left side to the right side.

  Also, in the third core 43, similarly to the second core 36, a shaping protrusion 46 having a half shape of the other shaping protrusion 45 is formed on the terminal on the first core 34 side. The first core 34 is in contact with the first core 34. The reason why the convex portion 39 and the protruding portion 46, which are half the shape of the other protruding portion 38 and the protruding portion 45, are brought into contact with the first core 34 at the terminal on the first core 34 side is the horizontal linear concave portion. This is because the thickness in the vicinity of the connecting portion between 16a and the vertical line-shaped recess 16b is connected in a thin state, and is smoothly broken.

  The fourth core 49 is disposed on the end portion side of each third core 43 away from the first core 34 and has one shaping protrusion having a shape substantially the same as the shaping protrusion 45. 50 is arranged on the tip side. The fourth core 49 is a part that molds the end part of the vertical linear recess 16b that is separated from the horizontal linear recess 16a in the planned fracture part 16, and is a recess 47 of the third core 43 when the mold is closed. The shaping projection 50 is configured to project from an end face 51 that is arranged flush. Then, when the third core 43 is separated from the first core 34 after the injection of the molding material M, the fourth core 49 has a continuous edge 45b inclined toward the rear side in the moving direction of the shaping projection 45. In other words, in order to be able to form the connecting groove portion 24 for connecting the thin portions 20 and 20 of the concavo-convex portion 19 by cutting the portion of the thick portion 21, in other words, the shaping projection 45 moves by one pitch. In order to be able to secure a distance, it is arranged so that it can be pulled away from the split mold 31.

  In the airbag cover 10 according to the embodiment, the vicinity of the end of the vertical line-shaped recess 16b in the protruding opening 12 away from the horizontal line-shaped recess 16a is gradually increased in thickness so that the breaking at the time of breakage is greater than or equal to a predetermined value. The shaping protrusion 45 of the third core 43 and the shaping projection 38 of the second core 36 are provided so that the shape can be secured. On the end side away from the first core 34, the height is gradually lowered, and the protrusion 50 of the fourth core 49 has the lowest height.

  When the third core 43 moves away from the first core 34 after the injection of the molding material M, the shaping protrusion 45 close to the shaping protrusion 50 is aligned with the height of the protrusion 50 before drawing. In this way, the third core 43 is moved slightly away from the split mold 31 side.

  When manufacturing the airbag cover 10 using the molding die 30, first, the height positions of the end surface 51 and the recess 47 are made to coincide with the height position of the shaping recess 40, and the molding material M is injected. The third and fourth cores 43 and 49 are split by arranging the shaping concave portion 40 of the continuous side shaping portion 37 and the hollow portion 47 of the connection side shaping portion 44 along the left-right direction as the direction. 32. At this time, in the embodiment, the shaping protrusions 38 and 39 and the shaping projections 45 and 46 have the same shape along the left-right direction, so that they overlap each other, and the shaping Both the recess 40 and the recess 47 have the same opening shape along the left-right direction, and substantially equilateral triangular openings that coincide with each other are formed along the left-right direction.

  Then, in this state, the mold is closed, and the molding material M is injected into the cavity 30a from the gate 30b. When the molding material M is completely filled and the molding material M starts to solidify, AB in FIG. 12A and 12B, each fourth core 49 is pulled out away from the mold surface 31a of the split mold 31. Then, as shown in FIGS. 10A and 10B and FIGS. 12C and 12D, each third core 43 is moved by one pitch of the shaping protrusion 45 so as to be away from the first core 34. Then, the mold may be opened to release the molded airbag cover 10.

  When the air bag device S is mounted on a vehicle, the air bag 4 and the inflator 7 that are stored and folded by the retainer 5 are stored and held in the case 6 by using bolts 5a and nuts 6. The airbag assembly 10 is covered with the airbag cover 10, and the peripheral edge of the locking hole 28 e is locked to each locking claw 8 c, and then the airbag assembly with the airbag cover 10 already assembled is mounted. Then, it is inserted through the opening 2b of the instrument panel 2 mounted on the vehicle in advance, and each locking leg 27a is locked to the opening peripheral edge 2c, and the bracket 8d of the case 6 is fastened to the body 1 side. The airbag device S can be mounted on the vehicle by connecting a lead wire for inputting a predetermined actuation signal extending from the airbag actuation circuit to the inflator 7.

  When the airbag device S is operated, if the inflation gas from the inflator 7 flows into the airbag 4 and the airbag 4 is inflated, the airbag 4 abruptly pushes the protruding opening 12 and thus breaks. The planned portion 16 is broken so that the door portions 13 and 14 of the airbag cover 10 are opened to the front and rear sides, and the opening 12a formed to open can be used to protect a passenger seated in the passenger seat. It will protrude.

  In the method of molding the airbag cover 10 according to the embodiment, when the molding material M at the time of molding is injected, the injection direction of the molding material M as shown in FIG. 8B, FIG. 9A, and FIG. And the shaping recess 40 of the continuous side shaping portion 37 of the second core 36 in the molding die 30 and the shaping depression 40 and the height of the connection side shaping portion 44 of the third core 43 along the left-right direction. A recess 47 having the same height is juxtaposed. Therefore, the molding material M to be injected is continuously applied from the upstream side to the downstream side of the molding material M with the site of the planned fracture portion 16b at the site of the planned fracture portion 16b on the back surface side of the airbag cover 10. It flows smoothly through the material flow path R in a state where there is no interference formed by arranging the shaping concave portion 40 of the shape portion 37 and the recess portion 47 of the connection side shaping portion 44 side by side. The opening of the material flow path R is an opening in the region from the inner peripheral surface of the shaping recess 40 or the recess 47 to the mold surface 31 a of the split mold 31, and the shaping projection 38 adjacent to the shaping recess 40. Is larger than the gap between the top portion 38b and the split mold surface 31a, and the number of the flow paths R is plural (many). Therefore, the molding material M flows smoothly so as to straddle the vertical line-shaped recess 16b of the planned fracture portion 16 so as to straddle the orthogonal direction, and the filling failure of the molding material M in the cavity 30a can be prevented. .

  Since the plate-like first core 34 is disposed on the end surface 34a side along the injection direction of the molding material M at the site of the horizontal linear recess 16a of the planned fracture portion 16, the molding material M is It will flow along the core 34 to the downstream side without hindrance.

  Thereafter, when the molding material M starts to solidify, the fourth cores 49 are pulled away from the split mold 31 as shown in FIGS. 9A and 12B, and then, as shown in FIGS. 12, the connecting side shaping portion 44 of each third core 43 is moved away from the first core 34, and each shaping projection 45 of the connection side shaping portion 44 is moved. 46 is moved so as to pass between the shaping convex portions 38 and 38 of the continuous side shaping portion 37 and between the convex portions 38 and 39 to form the connecting groove portion 24, and then the molded airbag cover 10. If the mold is released, the manufactured airbag cover 10 can be obtained.

  In the embodiment, when the airbag cover 10 is molded, the connecting-side shaped portion 44 of the molding die 30 moves only along the vertical line-shaped recess 16b at the portion of the vertical line-shaped recess 16b. Since it does not move to the surface side that is the design surface side of the cover 10, an indentation or the like that lowers the design property is not generated on the design surface of the airbag cover 10.

  Therefore, in the method of forming the airbag cover 10 according to the embodiment, the flow of the molding material M at the time of molding can be made smooth, and the occurrence of indentation or the like that deteriorates the design is prevented, and the airbag cover 10 is manufactured. can do.

  And in the airbag cover 10 manufactured by embodiment, it is arrange | positioned as the recessed part 16b which forms the fracture | rupture planned part 16 in one edge side of the orthogonal | vertical direction with the arrangement | positioning direction of the vertical linear recessed part 16b in the vertical linear recessed part 16b. In addition, the continuous uneven portion 19 formed by alternately and continuously providing the thin portions 20 and the thick portions 21, and the other edge side in the direction perpendicular to the arrangement direction of the vertical linear recess 16b in the vertical linear recess 16b And a connecting portion 23 having a connecting groove portion 24 arranged so as to connect adjacent thin-walled portions 20 and 20 of the continuous concave-convex portion 19. Since the thin wall portion 20 of the continuous concave-convex portion 19 and the connecting groove portion 24 of the connecting portion 23 form a continuous thin portion so as to follow, the vertical line-shaped concave portion 16b is broken by being pushed by the airbag 4. At the time, the thin portion 2 of the continuous uneven portion 19 Walled portion communicating with the connecting groove portion 24 of the connecting portion 23 and is then smoothly break, will form the projection opening 12a of the airbag 4.

  In addition, in the site | part of the horizontal linear recessed part 16a of the planned fracture | rupture part 16, the thin part 17 of uniform thickness is formed, and it will fracture | rupture smoothly.

  And in such an airbag cover 10, the continuous side shaping | molding which has the shaping | molding convex part 38 and the shaping recessed part 40 which can shape | mold the thin part 20 and the thick part 21 of the above-mentioned continuous uneven | corrugated | grooved part 19 is possible. It has the shape 37 which can form the part 37, the connection groove part 24 of the connection part 23, and the hollow part 47 arrange | positioned between the shaping protrusions 45, and it can move along the vertical linear recessed part 16b. If the molding die 30 provided with the connecting side shaping portion 44 is used, the flow of the molding material M at the time of pouring can be improved, and a defective product is generated without causing indentation or the like on the design surface. Thus, it is possible to manufacture with good yield.

  In particular, in the airbag cover 10 manufactured in the embodiment, the connecting groove portion 24 arranged so as to connect the thin portions 20 and 20 of the continuous uneven portion 19 has a thin portion 20 as shown in FIGS. The concave portion 19b is arranged so as to connect the minimum thickness portion 20a at the bottom portion 19b of the concave portion 19a, and further provided with a concave portion 23b having a narrow groove-shaped opening width as cut by a cutter, thereby providing a vertical linear concave portion 16b. Since the rupture line at the time of rupture is formed in a straight line along the connecting groove portion 24, the portion of the vertical line-shaped recess 16b can be broken more smoothly. It becomes.

  Moreover, in embodiment, the shaping | molding convex part 38 of the continuous side shaping part 37 and the shaping | molding protrusion part 45 of the connection side shaping part 44 make the opposing surfaces 38a and 45a mutually flat surfaces which can be slidably contacted. The shaping projection 45 is formed on the moving direction side where the shaping projection 45 of the connection side shaping portion 44 is arranged between the shaping projections 39 of the continuous side shaping portion 37, and the continuous side shaping. The edge 45b side on the shaping convex portion 39 side of the shape portion 37 is formed in an acute angle shape (60 ° in the embodiment) as a cross-sectional shape along the back surface of the airbag cover 10.

  Therefore, even when the molding material M is hardened and solidified during the movement in which the shaping projection 45 of the connection side shaping portion 44 is disposed between the shaping convex portions 38 of the continuous side shaping portion 37, an acute angle is obtained. The edge 45b side formed in the shape bites into the hardened and solidified molding material while cutting and smoothly arranging the shaping projection 45 between the shaping convex portions 38, 38 of the continuous side shaping portion 37, The connecting groove portion 24 can be formed.

  From such a viewpoint, molding may be performed using molding dies 30A and 30B as shown in FIGS.

  The forming die 30A shown in FIG. 13 is formed such that the continuous side shaping portion 37A of the second core 36A protrudes from the flat bottom surface of the shaping concave portion 40 with the substantially square columnar shaping convex portions 38 and 39. ing. Further, the connecting side shaping portion 44A of the third core 43A is formed by projecting a substantially triangular prism shaped shaping projection portion 45A from the bottom surface of the hollow portion 47 flush with the bottom surface of the shaping recess 40. ing. The cross-sectional shape of the shaping protrusion 45A is a right isosceles triangle, and the angle of the edge 45b on the moving direction side is an acute angle of about 45 °.

  Further, in the molding die 30B shown in FIG. 14, the continuous side shaping portion 37B of the second core 36B is formed by projecting a substantially square columnar shaping convex portion 38 from the flat bottom surface of the shaping concave portion 40. ing. Further, the connecting side shaping portion 44B of the third core 43B is formed by projecting a substantially triangular prism shaped shaping projection 45B from the bottom surface of the recessed portion 47 flush with the bottom surface of the shaping recess 40. ing. The cross-sectional shape of the shaping protrusion 45B is a right triangle, and the angle of the edge 45b on the moving direction side is an acute angle of about 60 °.

  In these molding dies 30A and 30B, the shaping projections 45A and 45B of the connection side shaping portions 44A and 44B are arranged between the shaping convex portions 38 and 38 of the continuous side shaping portions 37A and 37B. Even when the molding material M is hardened and solidified at the time of movement, the edge 45b side formed in an acute angle bites into the hardened and solidified molding material and smoothly forms the continuous side shaping portions 37A and 37B. The connecting groove portion 24 can be formed while arranging the shaping protrusions 45A and 45B between the convex portions 38 and 38.

  Of course, as long as the connecting groove can be formed in a state where the molding material is hard and not solidified, it may be configured as a molding die 30C shown in FIG. In this mold 30C, the continuous side shaping portion 37C of the second core 36C is formed by projecting the substantially quadrangular prism shaped shaping convex portions 38, 39 from the flat bottom surface of the shaping concave portion 40. Further, the connecting side shaping portion 44C of the third core 43C is formed by projecting a substantially square columnar shaped projection 45C from the bottom surface of the recess 47 that is flush with the bottom surface of the shaping recess 40. The angle of the edge 45b on the moving direction side of the shaping protrusion 45C is approximately 90 °.

  Note that members 49A, 49B, and 49C shown in FIGS. 13, 14, and 15 are fourth cores that are pulled out when the connecting side shaped portions 44A, 44B, and 44C are moved.

  Moreover, in the case of embodiment, the edge 45b of the moving direction side formed in the acute angle shape in the shaping projection part 45 is inclined and formed in the movement direction side toward the front end side of the shaping projection part 45. Therefore, it becomes easier to cut the hardened and solidified molding material M at the time of movement, and the connecting groove portion 24 can be formed smoothly.

  In addition, in the case where the edge 45b on the shaping convex portion 38 side and the moving direction front side in the shaping projection portion 45 is not inclined toward the moving direction rear side toward the tip side, for example, a hollow portion 47 as shown in FIG. In the case of forming the edge 45b of the shaping projection 45C in an upright state, the movement of the shaping projection 45C by one pitch is not necessary at the time of the step C before the step D in FIG. The molded airbag cover may be released. In this case, the connecting groove portion 24 can be formed so that the shaping protrusion 45C arranged in the step C in FIG. 15 connects the thin portions 20 and 20 formed by the shaping projection 38. is there.

  Furthermore, in the shaping convex part of the continuous side shaping part of the molding die and the shaping projection part of the connecting side shaping part, the tip side of the shaping convex part and the shaping protrusion arranged on the upstream side of the molding material In order to go to the downstream side of the molding material, it may be inclined or an arc surface. For example, in the shaping convex part 38 on the upstream side of the molding material M shown in FIG. 15, an arc surface 38b is formed on the upstream edge of the tip.

  In the embodiment, the airbag cover 10 having the instrument panel 2 used in the passenger seat airbag device S as a separate body has been described. However, the present invention may be applied to an airbag cover integrally formed with the instrument panel. Furthermore, the present invention may be applied to an airbag cover such as an airbag device provided for another driver's seat or on the side surface of the seat.

It is a perspective view which shows the use condition of the airbag cover manufactured with the shaping | molding method of one Embodiment of this invention. It is sectional drawing of the airbag apparatus in which the airbag cover of the embodiment is used, and respond | corresponds to the II-II site | part of FIG. It is sectional drawing of the airbag apparatus in which the airbag cover of the embodiment is used, and respond | corresponds to the III-III site | part of FIG. It is a partial bottom view of the airbag cover of the embodiment. It is sectional drawing of the airbag cover of the embodiment, and respond | corresponds to the VV site | part of FIG. It is sectional drawing of the airbag cover of the embodiment, and respond | corresponds to the VI-VI site | part of FIG. It is sectional drawing of the airbag cover of the embodiment, and respond | corresponds to the VIIA-VIIA site | part of FIG. 4, and the VIIB-VIIB site | part, respectively. It is a fragmentary longitudinal cross-section which shows the use condition of the shaping | molding die of the airbag cover of the embodiment. It is a fragmentary perspective view explaining the operation state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the embodiment. It is a fragmentary perspective view explaining the action | operation state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the embodiment, and shows the state after FIG. It is a fragmentary perspective view of the core which comprises the continuous side shaping part and the connection side shaping part in the shaping | molding die of the embodiment. It is a top view explaining the operation state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the embodiment. It is a top view explaining the operation state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the modification of embodiment. It is a top view explaining the operating state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the other modification of embodiment. It is a top view explaining the operation state of the continuous side shaping part and the connection side shaping part in the shaping | molding die of the further another modification of embodiment.

Explanation of symbols

4 ... Airbag,
10 ... Airbag cover,
12a ... projecting opening,
16b (scheduled break portion) vertical linear recess,
19 ... continuous uneven part,
20 ... Thin part,
21 ... Thick part,
23 ... connecting part,
24 ... connecting groove,
30 / 30A / 30B / 30C ... mold,
30b ... Gate,
37, 37A, 37B, 37C ... Continuous side shaping part,
38.39 ... Shaping convex part,
38a, 45a ... opposite surface,
40 ... shaped recess,
44, 44A, 44B, 44C ... Connection side shaped part,
45 · 45A · 45B · 45C · 46 · 50 ... shaping protrusion,
45b ...
47 ... depression,
M: Molding material.

Claims (4)

A method of forming a synthetic resin airbag cover that covers a folded airbag and is pushed by the airbag when inflated to break a thinly-scheduled breakage portion to form a protruding opening of the airbag. There,
The portion to be broken is
While being formed by a recess provided on the back side of the airbag cover along the planned break portion,
A continuous concavo-convex portion formed by alternately and continuously providing thin-walled portions and thick-walled portions disposed on one edge side in the direction perpendicular to the disposition direction of the planned breakage portion in the planned breakage portion;
The thick portion is disposed on the other edge side in the direction orthogonal to the disposition direction of the planned break portion in the planned break portion, and is disposed so as to connect adjacent thin portions of the continuous uneven portion. A connecting portion having a connecting groove portion having a thinner thickness;
Configured with
The mold surface of the molding die at the site of the planned fracture portion on the back surface side of the airbag cover had a shaping convex portion and a shaping concave portion capable of molding the thin portion and the thick portion of the continuous uneven portion. A continuous side shaping portion, a shaping projection that can form a coupling groove of the coupling portion, and a depression that is disposed between the shaping projections and has the same height as the shaping recess, A connection side shaping portion movable along the planned breaking portion,
At the time of molding, at the part of the planned break portion on the back side of the airbag cover, the molding material is injected along the direction orthogonal to the arrangement direction of the planned break portion, and the continuous along the injection direction of the molding material. The molding material is allowed to pass through by arranging the shaping concave portion of the side shaping portion and the hollow portion of the connecting side shaping portion side by side,
After the injection, the connecting side shaping portion is moved to form the connecting groove portion while the shaping projection portion of the connecting side shaping portion is arranged between the shaping convex portions of the continuous side shaping portion, A method for forming an airbag cover, comprising releasing the molded airbag cover. The shaping convex part of the continuous side shaping part and the shaping projection part of the coupling side shaping part are formed as opposed planes that can slide against each other,
The shaping protrusion is on the moving direction side where the shaping protrusion of the coupling-side shaping part is arranged between the shaping convex parts of the continuous-side shaping part, and shaping of the continuous-side shaping part 2. The method of forming an airbag cover according to claim 1, wherein the edge side on the convex portion side is formed in an acute angle as a cross-sectional shape along the back surface of the airbag cover.   The edge on the movement direction side formed in an acute angle shape in the shaping protrusion is inclined toward the rear side in the movement direction toward the tip side of the shaping protrusion, and is formed. A method for forming an airbag cover as described in 1. above. A synthetic resin airbag cover that covers the folded airbag and is pushed by the airbag when inflated to rupture the thinly-scheduled breakage portion to form a protruding opening of the airbag,
The portion to be broken is
While being formed by a recess provided on the back side of the airbag cover along the planned break portion,
A continuous concavo-convex portion formed by alternately and continuously providing thin-walled portions and thick-walled portions disposed on one edge side in the direction perpendicular to the disposition direction of the planned breakage portion in the planned breakage portion;
The thick portion is disposed on the other edge side in the direction orthogonal to the disposition direction of the planned break portion in the planned break portion, and is disposed so as to connect adjacent thin portions of the continuous uneven portion. A connecting portion having a connecting groove portion having a thinner thickness;
An air bag cover comprising:

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