JP2003025385A - Mold for injection molding and method for molding air bag door using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding to integrally mold an air bag door with an instrument pane without bringing about an underfill while holding a beauty and to provide a method for molding the air bag door using the same. SOLUTION: The mold for injection molding comprises a first mold unit 3 and a second mold unit 4 for specifying an air gap 14 for filling a resin material 15, a core 7 provided at the second mold unit 4 to form a fracture part movable to advance from or retract to the first mold unit 3, and heating means 7, 16 provided at the first unit 3 and/or the second unit 4 along the fracture part formed at the material 15 filled in the gap 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for use in integrally molding an airbag door with an instrument panel, and an airbag door molding method using the same. .

[0002]

2. Description of the Related Art In recent years, high-speed moving vehicles such as automobiles have
An airbag system is often installed for the purpose of ensuring the safety of passengers. The airbag system, when a vehicle is impacted in a collision accident,
A device for absorbing the transmission of the impact to an occupant, which is generally a sensor that detects an impact on a vehicle and determines the degree of the impact and sends an operation signal, and a required signal based on the operation signal. It is composed of a gas generator that generates gas and an airbag that inflates and deploys by the gas from the gas generator to protect an occupant.
An airbag that inflates and deploys when the airbag system is activated is normally folded and stored at a predetermined position when the airbag system is not activated. For example, a passenger airbag in an automobile airbag system is housed inside an instrument panel. Therefore, the instrument panel in which the airbag is housed has an opening for allowing the airbag to bulge toward the occupant in the event of system operation emergency, and the opening for closing the system in normal operation. An airbag cover body or an airbag door for opening the opening when the system is operated is required.

FIG. 7 is a perspective view of an instrument panel 100 provided with a resin-molded airbag door 101 as a separate body by a conventional method, and FIG. 8 is a view of the instrument panel 100 shown in FIG. It is a partial cross-section enlarged perspective view of the installation location of the airbag door 101. Figure 8
The cross-sectional shape shown in corresponds to the cross-sectional shape along the line VIII-VIII in FIG. 7.

In forming an air bag door on an instrument panel, the instrument panel 1 is conventionally used.
00 and the airbag door 101 are resin molded separately from each other, and then the airbag door 101 is attached to the instrument panel 100 so as to close the airbag opening 102. However, when the airbag door 101, which is a separate member, is attached to the instrument panel 100, the airbag door 101 and the panel body are separated from each other on the outer surface or the design surface of the instrument panel 100, as well shown in FIG. A gap or step 103 is formed at the boundary of As shown in FIG. 7, such a gap or stepped portion 103 is not preferable because it affects the external appearance configuration of the instrument panel where aesthetics are emphasized. There is also a problem that dust easily collects in such a gap or step 103. In addition, in such a conventional configuration, an air bag door molding process independent of the molding of the panel body, a mold for the same, and the like are separately required, which makes the manufacturing process of the instrument panel complicated. Was there.

For example, JP-A-11-291069, JP-A-6-143327 and JP-A-2000.
Japanese Patent Laid-Open No. 108833 discloses a technique for integrally molding an airbag door and an instrument panel in order to solve the above-mentioned problems based on separate molding of an airbag door.

Specifically, according to Japanese Patent Laid-Open No. 11-291069, after the instrument panel body is injection molded without providing an airbag opening, a predetermined position corresponding to the airbag storage position on the back surface of the panel is provided. The broken portion is formed by shaving the portion with a laser.
Here, the rupture portion is formed to rupture when the airbag system receives an inflation force when the airbag system is activated, so that a predetermined portion of the instrument panel corresponding to the airbag storage position, that is, an airbag door can be ruptured. The vulnerable part. By forming such a broken portion in the instrument panel, the airbag door defined by the broken portion is formed integrally with the instrument panel.

On the other hand, according to JP-A-6-143327 and JP-A-2000-108833, the instrument panel mold is clamped so that a desired break is formed on the back side of the instrument panel. The fractured part forming core is arranged in advance in the void defined by, and the void is filled with the resin material in this state. Then, when the instrument panel is injection-molded, the airbag door defined by the break portion is integrally molded with the instrument panel.

[0008]

However, in the laser processing method described above, it is relatively difficult to finely adjust the thickness of the fractured portion formed on the instrument panel by laser irradiation, and in particular, the instrument having a single-layer structure is used. When laser processing is performed on the instrument panel, there is a possibility that the instrument panel may be penetrated by excessive laser irradiation. Moreover, if the laser processing method is adopted,
In addition to the injection molding process of the instrument panel, a complicated laser processing machine is required, resulting in a decrease in manufacturing efficiency of the instrument panel.

On the other hand, in the method of preliminarily disposing the fracture portion forming core at the time of injection of the resin material, the core has a fracture portion or a thin portion formed in the instrument panel, so that the core is smaller than other die portions. Since it is arranged so as to project into the void, it becomes an obstacle to the resin material flowing in the void. Then, it becomes difficult to supply a sufficient amount of resin to the region sandwiched between the cores or the enclosed region, that is, the airbag door forming region. As a result, there is a problem of so-called wall-thickness that a part or the whole of the airbag door integrally formed with the instrument panel becomes thinner than a desired wall thickness.

The present invention has been conceived under such circumstances, and an object thereof is to solve or reduce the above-mentioned problems, and a flesh is generated while maintaining aesthetics. It is an object of the present invention to provide an injection molding die that can be used when integrally molding a non-airbag door to an instrument panel, and an airbag door molding method using the same.

[0011]

DISCLOSURE OF THE INVENTION According to a first aspect of the present invention, an injection mold is provided. The mold is provided on the first mold body and the second mold body for defining the space filled with the resin material, and the second mold body, and is movable back and forth with respect to the first mold body. A core for forming a broken portion, and heating means provided on the first mold body and / or the second mold body along the broken portion formed in the resin material with which the void is filled. Is characterized by.

When the mold having such a structure is used, it is possible to avoid or sufficiently suppress the occurrence of wall thickness in the airbag door when the airbag door is integrally molded with the instrument panel, for example. . Specifically, in the injection molding using the mold according to the first aspect of the present invention as an instrument panel mold, in the resin material injection step, the fractured part forming core is retracted from the fractured part forming position. It is possible to inject the resin material into the void portion in the position, and then to displace the fracture portion forming core to the fracture portion forming position during or after filling the resin material into the void portion. According to this, the fracture portion forming core does not or hardly obstructs the flow of the resin material in the void portion, and a sufficient amount of the resin material is provided for the airbag door forming region defined by the fracture portion forming core in the void portion. Can be supplied. As a result, the occurrence of deficiency in the finished airbag door is avoided, and the airbag door having a desired wall thickness is integrally formed with the instrument panel.

Further, by using the mold according to the first aspect of the present invention, the airbag door can be integrally formed with the instrument panel with good appearance. When the fracture portion forming core is displaced to the fracture portion forming position during or after the filling of the resin material as in the above-mentioned injection molding, the tip of the fracture portion forming core and the The resin material sandwiched between the first mold body, that is, the resin material forming the fractured portion is in a state of being pressed more than the resin existing in other regions. When the resin material radiates heat and shrinks in the cooling step after the resin material injection step, the resin material forming the fractured part is originally compressed, so the resin material in the member thickness direction is compressed more than the resin material forming the other parts. Will shrink at a low shrink rate. By using the mold according to the first aspect of the present invention, it is possible to appropriately cope with such a difference in shrinkage speed of the resin material, and in a molded product obtained after cooling is completed, the panel body and the airbag door are The outer surface can be formed into a shape in which the outer surfaces are connected flush with each other.

Specifically, since at least one of the first and second mold bodies is provided with a heating means along the fractured portion formed in the resin material filled in the voids, the metal mold is heated. When the mold is used, the fractured portion can be heated from the time the resin material is filled until the mold is opened. When the fractured part is heated to a higher temperature than other parts by heating the fractured part in this way, in the cooling step such as cooling after taking out the molded product from the mold, regarding the fractured part, The time required to reach the final cooling and solidifying temperature is longer than that of other parts. That is, the fractured part continues to significantly shrink even after the other parts reach the final cooling and solidifying temperature and substantially stop shrinking. Therefore, even if the fracture portion has a relatively low shrinkage speed, the final shrinkage amount may be the same as that of other portions. In this way, by heating the fractured part in the mold, the fractured part where the resin material was in a relatively high compression state in the cooling after the molded product was taken out from the mold Can be contracted to the same extent as other parts. As a result, it is possible to avoid impairing the aesthetic appearance of the instrument panel when integrally forming the airbag door without causing a thickness deficiency.

If the die is not provided with a breaking portion heating means, the resin material of the breaking portion in a relatively high compression state is heated to a high temperature state before the die is opened. I can't. Then, in the cooling step after taking out the molded product from the mold, the fractured portion and other portions have substantially the same time required to reach the final cooling and solidifying temperature. Regarding the amount of shrinkage during this period, the fractured portion having a relatively low shrinkage rate is smaller than other portions. As a result, on the design surface of the finally obtained instrument panel, the fractured part is in a state of bulging more than other parts, which spoils the aesthetic appearance of the instrument panel.

According to a second aspect of the present invention, there is provided a method of integrally forming an airbag door on an instrument panel. This molding method includes a step of bringing a first mold body and a second mold body close to each other to perform mold clamping, and a first mold body and a second mold body.
In the step of injecting the resin material into the void defined by the mold body and in the process from the injection of the resin material to the solidification of the resin material, the second mold body is provided with the first mold body. A step of displacing the breakable part forming core that can move forward and backward toward the first mold body from the retracted position to the breakable part forming position to form the breakable part, and the first mold body along the breakable part. And / or a step of heating the rupture portion by a heating means provided in the second mold body.

With this structure, the air bag door can be integrally formed on the instrument panel by using the mold according to the first aspect of the present invention. Therefore, according to the second aspect of the present invention as well, the same effect as that described above with respect to the first aspect is achieved.

The resin materials used in the injection molding according to the present invention include styrene resins, polyolefin resins,
A thermoplastic resin such as a polyphenylene ether (PPE) resin can be used. Further, from the viewpoint of reinforcing the resin molded body, the resin material may include an inorganic filler such as glass fiber, carbon fiber, calcium carbonate, talc, or mica.

In the present invention, the fractured part forming core has a desired edging shape corresponding to the airbag, and the tip thereof may be formed in a tapered shape, or may be formed in the second mold body. A flat surface substantially parallel to the void defining surface may be formed. Further, in the second aspect of the present invention, preferably, the retracted position of the core is the position where the tip of the core is on the same plane as the void defining surface of the second mold body or retracts from the void defining surface. As long as there is no deficiency in the airbag door of the finished product, it is the position retracted from the fracture formation position, and the tip of the core is located at the first mold body rather than the void defining surface. The position extending toward the core may be the retracted position of the core. When such a configuration is adopted, the length of the core extending from the void defining surface is preferably ½ or less, more preferably ⅕ or less of the thickness of the airbag door. Yes, more preferably 1/10
It is the following. When a core having a flat surface substantially parallel to the void defining surface at its tip is used, the position where the flat surface is flush with the void defining surface of the second mold is referred to as the retracted position of the core. By doing so, it is possible to properly prevent the resin material from excessively flowing into the groove portion formed in the second mold body as the sliding portion of the core.

In a preferred embodiment, the heating means is realized by a fracture forming core having a heater therein. Instead of or in addition to this, the heating means may be realized by a heating core internally provided with a heater and fitted into the first mold body. With such a configuration, it is possible to satisfactorily heat the fractured portion.

In the present invention, preferably, the first mold body is a fixed mold supported and fixed to a fixed mold mounting plate of the injection molding apparatus, and the second mold body is a movable mold mounting plate of the apparatus. It is a movable type that is supported and fixed to and is movable back and forth with respect to the fixed type. And, preferably, the fixed mold is provided with an injection hole which is open on the surface thereof and is continuous with the void, and in the resin material injection step, the resin material in a molten state prepared by an injection device is used. It is injected into the void through this injection hole.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a partial sectional view of an injection molding apparatus equipped with an injection molding die A according to the first embodiment of the present invention. FIG. 1 shows the structure of the airbag door forming region S and its vicinity. Here, the airbag door forming region S is a region corresponding to a portion defined by the fractured portion in the completed instrument panel, that is, a portion functioning as an airbag door.

The injection molding die A is fixed to a fixed die 3 which is fixedly supported by a fixed die mounting plate 1 of an injection molding apparatus, and a movable die mounting plate 2 which can move back and forth with respect to the fixed die mounting plate 1. The movable mold 4 supported is provided. The stationary die 3 is provided with a stationary core 5 at a position corresponding to the airbag door forming region S. The fixed core 5 is fitted into the fixed mold 3 such that the exposed surface thereof is flush with the void defining surface 3a of the fixed mold 3, and the fixed core 5 has a heater and a temperature sensor (both not shown in the drawing) inside thereof. ) Is provided. The movable die 4 is provided with an airbag door forming mechanism 6 at a position corresponding to the airbag door forming region S.

The airbag door forming mechanism 6 has a core 7 having a peripheral shape corresponding to a desired breaking portion, a core support plate 8 for fixedly supporting the core 7, and a vertical movement of the support plate 8. Hydraulic cylinder 9 of. In order to dispose the airbag door forming mechanism 6, the movable mold 4 has
The core through groove 10, the support plate accommodating chamber 11, and the cylinder accommodating chamber 12 are provided.

The core 7 is provided with a heater 7a and a temperature sensor (not shown) inside thereof, and is configured so that the resin material 15 can be heated via the tip portion thereof during the molding process. The heater 7a can be composed of, for example, a heating wire or a cartridge heater.

The hydraulic cylinder 9 is fixed in the cylinder accommodating chamber 12 of the fixed die 4 and has a piston rod 9a which can extend and contract. The piston rod 9 a is connected to the support plate 8 in the support plate housing chamber 11. The support plate 8 moves up and down in the support plate housing chamber 11 by the expansion and contraction of the piston rod 9a. The core 7 supported and fixed to the support plate 8 is
When it moves up and down together with the support plate 8, it is slidable in the core through groove 10 that is opened corresponding to the shape of the core 7. The core 7 is supported by the hydraulic cylinder 9 on the support plate 8
Is positioned through. In the cross-sectional view of FIG. 1, three cores 7 are apparently shown, but these are connected outside the drawing to form an integral core 7. Also, core 7
In order to prevent the movement direction of the support plate 8 from inclining from the piston expansion / contraction direction, a guide post 13 penetrating the support plate 8 in a direction parallel to the piston expansion / contraction direction is fixed to the support plate storage chamber 11. There is.

The injection molding die A shown in FIG. 1 has an arrangement of a mold clamping step in a series of steps for integrally molding an airbag on an instrument panel. In the mold clamping step, the movable mold 4 is integrated with the movable mold mounting plate 2 to approach the fixed mold 3, and is fitted to the fixed mold 3 at a predetermined position (not shown). In a state where the movable die 4 is fitted to the fixed die 3, that is, a mold clamping state, a void portion 14 as a space filled with resin is formed between the two dies. In this embodiment,
The width W of the airbag door forming region S in the void portion 14 is set to 1 to 5 mm. In the mold clamping process, the core 7 is positioned at the retracted position by the hydraulic cylinder 9,
It is in a standby state. In the present embodiment, the retracted position refers to a position where the upper end of the core 7 is retracted from the gap defining surface 4a of the movable die 4.

FIG. 2 shows a resin material injection step which is performed subsequent to the mold clamping step. In this step, the resin material 15 in a molten state is filled in the void portion 14 formed in the mold clamping step. Specifically, the resin material 15 melted by a resin injection device (not shown) is ejected from the injection device through an injection hole (not shown) formed in the fixed mold 3 so as to communicate with the cavity 14, Is injected into the void portion 14 under the pressure of. At this time,
The core 7 is kept waiting in the above retracted position. Therefore, when the resin material 15 passes through the air bag door forming area S in the void portion 14, the tip portion of the core 7 does not hinder the flow of the resin material 15, and the air bag door forming area S is sufficiently large. The resin material 15 is supplied. At this time,
The core 7 is temperature-controlled in the range of 40 to 100 ° C. by the functions of the heater 7 a and the temperature sensor incorporated therein. Further, the fixed core 5 is temperature-controlled in the range of 40 to 100 ° C. by the functions of the built-in heater and the temperature sensor, and heats the molten resin passing through or filling the airbag door forming region S. There is. By such heating, it is possible to appropriately prevent the resin material 15 from solidifying before the next fracture portion forming step.

FIG. 3 shows a fractured part forming step performed after the void portion 14 is filled with the resin material 15. In this step, the hydraulic cylinder 9 extends and drives the piston rod 9a to advance the support plate 8 and the core 7 supported and fixed to the support plate 8 from the retracted position to the fracture portion formation position. Here, the breaking portion forming position means that the tip end portion of the core 7 is pushed into the void portion 14 already filled with the resin material 15 to break the thin wall which is a boundary between the main body of the instrument panel and the airbag door. It means the position where a part is formed. The upper end of the core 7 and the fixed core 5 at the breaking portion forming position
The distance between and is, for example, 0.1 to 1.5 mm.

After the core 7 is displaced to the breaking portion forming position, the fixed core 5 stops the heating operation which has been continued until then. Then, for 1 to 20 seconds after the completion of the filling of the resin material, the core 7 is made to stand by at the breaking portion forming position until the molten resin material 15 is solidified to the extent that it does not lose its shape, and the resin material 15 filled in the void portion 14 is filled. Keep the pressure. At this time, core 7
In the temperature range of 40 to 100 ° C., the resin material forming the fractured portion is heated to maintain the fractured portion at a higher temperature than other portions. The pressure holding time may be set in advance in the device so that the device automatically moves to the next step after the time has elapsed, or the temperature provided in the fixed core 5 or the core 7 A device (not shown) may be used to detect the temperature of the resin material 15 filled in the voids 14 and automatically move to the next step when the temperature of the resin material 15 drops to a predetermined temperature. Good.

In this embodiment, the resin material 15 is used as the void portion 1.
The fractured part forming step is started after the resin material 15 has been completely filled into the space 4, but even before the complete filling, if the resin material 15 has passed through the air bag door forming region S in the void portion 14. The core 7 may be pressed into the resin material 15 in the void portion 14. Even if the fractured portion forming step is performed at such a timing, the resin material 15 has already been sufficiently supplied to the airbag door forming region S, so that the molded airbag door is free from wall thickness. In addition, the resin material 15
Can flow into the voids 14 other than the region S by bypassing the core 7 displaced to the fractured portion forming position, so that the problem of wall thinning can be avoided in other regions of the instrument panel.

FIG. 4 shows a core retreating step which is performed subsequent to the pressure holding step of the above-mentioned fracture portion forming step. In this step, the hydraulic cylinder 9 drives the piston rod 9a in a shortened manner to retract the support plate 8 and the core 7 supported and fixed to the support plate 8 from the break portion forming position to the retracted position. After this step, while making the core 7 stand by at the retracted position,
The movable die mounting plate 2 is driven to separate the movable die 4 from the fixed die 3 and open the die. Then, the molded instrument panel is taken out and subjected to a cooling step, that is, cooling. However, in the present invention, the core retreating step may be performed after the mold is opened and the instrument panel is taken out.

At the start of cooling in the cooling process, the core 7
The rupture part formed by the core 7 serves as a heating means.
Due to the heating up to that point, it is at a higher temperature than other parts. As the cooling progresses, the molded body continues to shrink as a whole. Regarding the degree of progress of contraction in the member thickness direction, the fractured portion where the constituent resin material has already been compressed in the member thickness direction in the fractured portion forming step is slower than the other portions.
In the cooling process, the temperature was originally relatively low,
The part that is not the fractured portion reaches the final cooling and solidifying temperature before the fractured portion, and the shrinkage is substantially stopped. Even after that,
The fractured part, which was originally relatively high in temperature, continues to cool and shrinks. When the fractured part reaches the final cooling and solidifying temperature and the shrinkage is substantially stopped, the amount of shrinkage of the fractured part becomes approximately the same as the amount of shrinkage of other parts.

FIG. 5 shows the airbag door 2 integrally formed with the instrument panel 20 by the series of steps described above.
It is a partial cross-sectional perspective view of FIG. Instrument panel 2
By forming a groove on the back surface side of 0, the fractured portions 22a, 2 having a contour shape as shown by a broken line and thinner than other portions
2b is formed. The fractured portions 22 a are formed by the cores 7 that are apparently present at both ends in FIGS. 1 to 4, and define the airbag door 21. On the other hand, the broken portion 22b is formed by the core 7 apparently located at the center in FIGS.
Cross 1.

Since the airbag door 21 is formed integrally with the instrument panel 20, the panel 20
There is no gap between the panel body and the airbag door 21 in terms of design. In addition, the airbag door 21
Has a sufficient thickness substantially corresponding to the void portion 14 at the time of injection molding, and an unduly thin portion in the member thickness is not formed. Therefore, when a pressing force is applied from the airbag which is inflated and deployed during system operation, the airbag door 21 is favorably disengaged from the instrument panel 20 due to the breakage of the breakage portion 22a and the breakage portion 22b.
It is possible to split well by breaking. If the groove depth is adjusted so that the fractured portion 22b is weaker than the fractured portion 22a, the fractured portion 22b is more likely to be fractured earlier when the airbag is inflated, and therefore, the vicinity of the center of the airbag opening is reduced. Swelling from the is secured. Fracture part 22a, 22b
Is not bulging on the outer surface or design surface (upper surface in the drawing) of the instrument panel 20, and on the design surface side,
The panel body and the airbag door 21 are connected in a flush manner. Therefore, the appearance configuration of the instrument panel 20 is not affected or restricted by the presence of the airbag door 21, and the aesthetic appearance of the instrument panel 20 is maintained.

In the present embodiment, the fractured portion 22 forming a rectangular shape.
Although the rectangular airbag door 21 is formed by forming a, a circular or other polygonal airbag door can be formed by appropriately changing the contour shape of the breakage portion 22a.

FIG. 6 is a partial sectional view of an injection molding apparatus equipped with an injection molding die B according to the second embodiment of the present invention. The injection molding die B includes a fixed core 5 ', which is different from that of the injection molding die A in the fixed die 3. In this fixed core 5 ', the void defining surface 5'a has a void defining surface 3a.
It is fitted into the fixed mold 3 so as to be flush with the inside, and a heater and a temperature sensor (both not shown) are arranged inside the fixed mold 3. Further, the fixed core 5'is provided with a fractured portion heating core 16. The fractured portion heating core 16 is fitted into the fixed core 5 ′ such that the exposed surface thereof is flush with the void defining surface 5′a, and the heater 16a and the temperature sensor are provided therein. (Not shown) is provided. The heater 16a is controlled independently of the heater of the fixed core 5 '. Other configurations are the same as those described above regarding the injection molding die A.

The injection molding die B shown in FIG. 6 has a mold clamping step in a series of steps for integrally molding an airbag on an instrument panel. In the mold clamping step, as described above with respect to the injection molding die A,
The movable die 4 is integrated with the movable die mounting plate 2 and approaches the fixed die 3 to form a void portion 14. The core 7 is positioned at the retracted position by the hydraulic cylinder 9,
It is in a standby state. Other configurations and operations are similar to those described above regarding the injection molding die A.

A series of steps after the mold clamping step are performed in substantially the same manner as described above for the injection molding die A with reference to FIGS. 2 to 4, but in the resin material injection step and the fracture portion forming step. The breaking core heating core 16 additionally functions. Specifically, when the resin material 15 passes through the air bag door forming region S in the void portion 14, the fracture portion heating core 16 heats the resin material 15 together with the fixed core 5 ′ at 40 to 100 ° C. There is. This appropriately prevents the resin material 15 from solidifying before the next fractured part forming step. At this time, the core 7 has a built-in heater 7a.
The temperature is controlled within the range of 40 to 100 ° C. by the function of the temperature sensor.

Next, in the step of forming the fractured portion, the core 7
Is displaced to the breaking portion forming position, and the fixed core 5 stops the heating operation that has been continuing until then, but at this time, the breaking portion heating core 16 is in the temperature range of 40 to 100 ° C., It is adjusted to the same temperature as the core 7. However, in the present invention, the fractured part heating core 16 may be adjusted to a temperature different from that of the core 7 as long as it is in the temperature range of 40 to 100 ° C. As a result, it becomes possible to satisfactorily heat the fractured part before opening the mold. The specific configuration of the subsequent steps is the same as when the injection molding die A is used.

Even when the injection molding die B is used, a panel design surface similar to that shown in FIG.
The airbag can be integrally molded with the instrument panel. That is, it is possible to maintain the aesthetic appearance of the instrument panel in terms of design.

The embodiment of the present invention has been described above by taking the airbag door of the passenger airbag as an example.
The present invention can also be applied to the airbag door of a steering airbag.

[0044]

According to the present invention, when the airbag door is integrally formed with the instrument panel,
It is possible to form an airbag door that does not have a wall deficiency. Further, according to the present invention, the breakage portion that defines the airbag door can be formed so as to be flush with other portions of the instrument panel design surface, and the appearance of the instrument panel design surface is impaired by the formation of the breakage portion. It is possible to eliminate or suppress the occurrence of this.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an injection molding device equipped with an injection molding die according to a first embodiment of the present invention.

FIG. 2 shows a resin material injection step in the airbag door molding method according to the present invention.

FIG. 3 shows a fracture portion forming step in the airbag door molding method according to the present invention.

FIG. 4 shows a core retreating step in the airbag door molding method according to the present invention.

FIG. 5 is a partial cross-sectional perspective view of an airbag door integrally molded with an instrument panel according to the present invention.

FIG. 6 is a partial cross-sectional view of an injection molding die according to a second embodiment of the present invention.

FIG. 7 is a perspective view of an instrument panel provided with an airbag door formed as a separate body by a conventional method.

FIG. 8 is a partial cross-sectional perspective view of an airbag door installation location in the instrument panel shown in FIG.

[Explanation of symbols]

A, B injection mold S Airbag door forming area 3 fixed type 4 movable 3a, 4a Void defining surface 5 fixed core 6 Fracture part formation mechanism 7 core 10 Core through groove 14 Void 15 Resin material 16 Fracture part heating core 20,100 Instrument panel 21,101 Airbag door 22a, 22b Fracture part

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29L 31:30 B29L 31:30 (72) Inventor Shinya Takemura 2-1-1 Taoyuan, Ikeda-shi, Osaka Daihatsu Industrial Co., Ltd. (72) Inventor Kazuto Ishida 2-1-1 Taoyuan, Ikeda-shi, Osaka Daihatsu Industrial Co., Ltd. F-term (reference) 3D044 BA07 BC07 BC13 BD04 3D054 AA14 BB09 4F202 AH25 CA11 CB01 CK06 CK35 CK54 CK84 CN01 CN18

Claims (4)

[Claims] 1. A first mold body and a second mold body for defining a void filled with a resin material, and a second mold body, which is provided on the second mold body and moves back and forth with respect to the first mold body. A movable fractured part forming core, and a heating means provided on the first mold body and / or the second mold body along the fractured part formed in the resin material with which the void is filled. An injection-molding die, comprising: 2. The injection-molding die according to claim 1, wherein the heating means is realized by the fracture-forming core having a heater therein. 3. The heating means is provided with a heater inside the first heating means.
It is realized by the heating core fitted in the mold of
The mold for injection molding according to claim 1 or 2. 4. A method of integrally forming an airbag door on an instrument panel, comprising a step of bringing a first mold body and a second mold body close to each other to perform mold clamping, and the first mold body. And a step of injecting a resin material into a space defined by the second mold body, and a step of injecting the resin material to solidifying the resin material, the resin material being provided in the second mold body. A step of displacing a rupture portion forming core that can move forward and backward with respect to the first mold body toward the first mold body from a retracted position to a rupture portion formation position to form a rupture portion; Heating the rupture portion by a heating means provided on the first mold body and / or the second mold body along a portion. Method.