JP4092033B2 - Manufacturing method of lid for airbag device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a lid for an airbag device for manufacturing a lid that is provided so as to cover an airbag device housed inside an instrument panel and has a tear line that is broken by the pressure of the inflating airbag. Regarding the method.
[0002]
[Prior art]
When the lid that covers the airbag device housed inside the instrument panel of an automobile is injection-molded, an “H” -shaped groove is formed on the back side of the lid, or a large number of blind holes are arranged in the “H” shape. Thus, a fragile tear line is formed, and the tear line is broken by a pressure at which an airbag is inflated.
[0003]
Japanese Patent Laid-Open No. 9-39706 discloses a lid in which a base material is injection-molded in a state where the skin material is inserted into a mold, and the skin material and the base material are laminated. A structure in which a tear line is formed by a recess formed by a processing horn of an ultrasonic welder is disclosed.
[0004]
[Problems to be solved by the invention]
By the way, in the former, since the thickness of the lid becomes uneven due to the grooves and blind holes formed on the back side of the lid, flow marks and sink marks are generated on the surface side of the lid during injection molding. In order to hide it, it was necessary to perform post-treatment such as painting on the surface of the lid.
[0005]
In the latter case, not only the appearance quality deteriorates because the recessed portion of the tear line is exposed on the surface side of the lid, but also the processing time is required because the tear line needs to be processed after the lid is injection molded. In addition, there is a problem that processing costs increase.
[0006]
The present invention has been made in view of the above-described circumstances, and an object thereof is to manufacture a lid having excellent appearance quality with a small number of man-hours.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the invention described in claim 1, there is provided a tear line that is provided so as to cover the airbag device housed inside the instrument panel and is broken by the pressure of the inflating airbag. In the method of manufacturing a lid for an airbag device for manufacturing a formed lid, the lid is formed by laminating a resin skin material on the front side and a resin base material on the back side, and the resin base material is made of gold. When molding with a mold, use the mold in which a plurality of pin-shaped protrusions corresponding to the tear line are provided at intervals on the cavity surface for molding the back surface of the resin base material. in the back surface side of the resin substrate, a plurality of stepped blind hole arranged at a mutual spacing in order to constitute the tear line so as to integrally formed, the respective pin-shaped projections, the cavity surface Stand up more And diameter, method of manufacturing a lid for an air bag device characterized in that it is formed in the small diameter portion and the second stage has a erected from the front end of the large diameter portion is proposed.
[0008]
According to the above construction, when molding a resin substrate of the lid in the mold, on the back side of the resin substrate, since the integrally molded a plurality of stepped blind bore which constitutes the tear line, resin The number of processing steps can be greatly reduced as compared with the case where the tear line is processed after the base material is formed. Moreover, since the resin skin material is laminated on the surface of the resin base material, the flow marks and sink marks generated on the surface of the resin base material are covered with the resin skin material, and without any post-treatment such as painting. The appearance quality of the lid can be improved.
[0009]
According to the invention described in claim 2, in addition to the structure of claim 1, the resin base material is molded with the resin skin material inserted into the mold. A method for manufacturing a lid for a bag device is proposed.
[0010]
According to the above configuration, when a resin base material is molded with a mold, a resin skin material is inserted in the mold in advance, so that the resin base material and the resin A skin material can be laminated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.
[0012]
1 to 10 show a first embodiment of the present invention. FIG. 1 is a perspective view of a front part of a passenger compartment of an automobile. FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. FIG. 4 is an explanatory view of a skin material clamping process, FIG. 5 is an explanatory view of a skin material heating process, FIG. 6 is an explanatory view of a vacuum process, and FIG. 7 is an explanatory view of a mold clamping / injection molding process. FIG. 8, FIG. 8 is an explanatory view of the cooling / release process, FIG. 9 is an enlarged view of 9 parts in FIG. 8, and FIG. 10 is an enlarged view of 10 parts in FIG.
[0013]
As shown in FIG. 1, a driver's seat 1 and a passenger seat 2 are provided in a front part of a passenger compartment of an automobile, and a driver's seat air is placed inside a steering wheel 3 disposed in front of the driver's seat 1. A bag device Rd is provided, and a passenger seat airbag device Rp is provided inside the instrument panel 4 in front of the passenger seat 2. A lid 6 covering the passenger seat airbag device Rp is formed integrally with an instrument panel 4 made of synthetic resin.
[0014]
As is clear from FIGS. 2 and 3, support walls 7... Extend downward from the back surface of the instrument panel 4 so as to surround the outer periphery of the lid 6. The passenger-side airbag device Rp includes an inflator 8 that generates high-pressure gas by combustion of propellant, a container-like lower retainer 9 having an open upper surface that accommodates the inflator 8, and the lower retainer 9 that supports the lid 6. 7. The upper retainer 12 fixed to the lower retainer 9 and the support wall 7 with bolts 10, 11, and the like, and the support wall 7 of the lid 6 in a folded state are housed inside the lid 6. And an airbag 13 fixed to the upper opening of the lower retainer 9 with the bolts 11. The lower retainer 9 is supported by a frame (not shown) disposed inside the instrument panel 4.
[0015]
On the back surface of the lid 6, an “H” type tear line 6 ₁ and two hinge lines 6 ₂ and 6 ₂ parallel to each other are formed (see FIG. 3). Tear line ₆₁ is composed of a number of blind holes 14 ... set of which is recessed in the rear surface (the surface of the opposing surfaces in the vehicle compartment opposite side) of the lid 6, also the hinge line 6 _2, 6 ₂ of the lid 6 It is comprised from the groove | channels 15 and 15 recessed in the back surface. Since the blind holes 14 ... and the hinge line 6 _2, 6 ₂ of the groove 15, 15 of the tear line ₆₁ is formed on the rear surface of the lid 6, from the surface side of the lid 6 is impossible visually.
[0016]
Thus, when an acceleration sensor (not shown) detects an acceleration of a predetermined value or more during a car collision, the inflator 8 of the passenger airbag device Rp ignites to generate high pressure gas, and the supply of the high pressure gas is received. The airbag 13 is inflated. When the pressure of the air bag 13 is inflated acts on the rear surface of the lid 6, a number of blind holes 14 ... tear line ₆₁ became fragile due to the formation of ruptures, hinge line becomes thin by the formation of grooves 15, 15 6 _2, the central portion of the lid 6 6 ₂ mainly has pushed open the cabin side, the airbag 13 therefrom which is formed in the opening is deployed into the passenger compartment.
[0017]
Next, a method for manufacturing the instrument panel 4 integrally provided with the lid 6 will be described with reference to FIGS.
[0018]
As shown in FIG. 4, a mold 16 for injection molding the instrument panel 4 includes a fixed mold 17 and a movable mold 18, and the movable mold 18 can be moved toward and away from the fixed mold 17. is there. The fixed mold 17 is provided with a runner 17 ₂ and a gate 17 ₃ connected to the cavity surface 17 ₁ . Further, the movable mold 18 is formed with a plurality of vacuum holes 18 _2, which are continuous with the cavity surface 18 ₁ .
[0019]
First, a skin material 19 made of a synthetic resin sheet (for example, thermoplastic polyolefin TPO) constituting the skin on the surface side of the instrument panel 4 is faced to the cavity surface 18 ₁ of the movable mold 18 opened. It fixes with the clamp member which is not shown (refer FIG. 4). Subsequently, the heater 21 is lowered to heat the skin material 19 fixed to the movable mold 18 with a clamp member (see FIG. 5). Subsequently, the vacuum hole 18 ₂ ... Of the movable mold 18 is evacuated to suck the skin material 19 that has been heated and softened by the heater 21 and is brought into close contact with the cavity surface 18 ₁ (see FIG. 6).
[0020]
When the skin material 19 is vacuum formed as described above, the heater 21 is retreated upward, the movable mold 18 is moved in a direction approaching the fixed mold 17, and the mold 16 is clamped and then fixed. The base material 22 of the instrument panel 4 is injection-molded by injecting molten synthetic resin (for example, thermoplastic polyethylene TPE) into the cavity through the runner 17 _{2 of the} mold 17 and the gate 17 ₃ (see FIG. 7). At this time, since the vacuum-formed skin material 19 is inserted into the cavity surface 18 ₁ of the movable mold 18, the injection-molded base material 22 and the vacuum-formed skin material 19 are laminated. Integrated. Subsequently, after the mold 16 is cooled, the movable mold 18 is moved away from the fixed mold 17 to open the mold, and the instrument panel 4 is removed from the fixed mold 17 to complete one cycle of molding. (See FIG. 8).
[0021]
As is apparent from FIGS. 8 to 10, when the base material 22 of the instrument panel 4 is injection-molded, the two protrusions 17 ₄ and 17 ₄ projecting from the cavity surface 17 ₁ of the fixed mold 17 Two grooves 15 and 15 corresponding to the two hinge lines 6 ₂ and 6 ₂ of the lid 6 are formed. Also the cavity surface 17 ₁ of the stationary mold 17 are pin-like projections 17 ₅ ... are protruded to form a large number of blind holes 14 ... which constitute the tear lines 6 ₁ "H" type. Blind holes 14 which are formed by pin-like projections 17 _5, from the back side of the base member 22 is formed in two stages and a large diameter portion and a small diameter portion, the small diameter portion tip of the skin material 19 It has reached the back side.
[0022]
As described above, the substrate 22 of the instrument panel 4 in injection molding in a mold 16 to form the tear line ₆₁ by the projections 17 ₅ ... provided in the mold 16 on the back surface of the base material 22 since, it is possible to significantly reduce the number of processing steps by eliminating the need to process the tear lines 6 ₁ after molding of the substrate 22. Further, even if a flow mark or sink mark is generated on the surface side of the base material 22, the outer appearance of the lid 6 is obtained without covering the flow mark or sink mark with the skin material 19 laminated on the surface and performing post-treatment such as painting. Quality can be improved. And since the base material 22 and the skin material 19 are laminated | stacked by insert molding, it becomes unnecessary to perform the lamination | stacking operation | work of the base material 22 and the skin material 19, and a process man-hour is reduced.
[0023]
As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0024]
For example, in the first embodiment shown in FIG. 9, the tip of the blind hole 14 reaches the back surface of the skin material 19, but the tip of the blind hole 14 is connected to the back surface of the skin material 19 as in the second embodiment shown in FIG. In this way, it is possible to reliably prevent the influence of the blind hole 14 from reaching the surface side of the skin material 19.
[0025]
In the embodiment, the lid 6 is formed integrally with the instrument panel 4, but the lid 6 may be formed of a member separate from the instrument panel 4.
[0026]
It is also possible to low-pressure molding the base member 22 of the re head 6 instead of injection molding.
[0027]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the resin base material of the lid is molded with a mold, it corresponds to the tear line on the cavity surface for molding the back surface of the resin base material. by using the mold obtained by projecting mutually spaced multiple pin-like projection which, forming a rear surface side of the resin substrate, a plurality of stepped blind bore which constitutes the tear line together As a result, the number of processing steps can be greatly reduced as compared with the case where the tear line is processed after the resin base material is molded. Moreover, since the resin skin material on the surface side of the resin base material is laminated, the flow marks and sink marks generated on the surface of the resin base material are covered with the resin skin material, and without any post-treatment such as painting. The appearance quality of the lid can be improved.
[0028]
According to the invention described in claim 2, when a resin base material is molded with a mold, a resin skin material is inserted into the mold in advance, so that no special laminating operation is performed. A resin base material and a resin skin material can be laminated.
[Brief description of the drawings]
1 is a perspective view of a front part of a passenger compartment of an automobile. FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1. FIG. 3 is an exploded perspective view of a lid and an airbag device. [Fig. 5] Explanatory drawing of skin heating process [Fig. 6] Explanatory drawing of vacuum process [Fig. 7] Explanatory drawing of mold clamping / injection molding process [Fig. FIG. 10 is an enlarged view of part 9 of FIG. 8. FIG. 11 is an enlarged view of part 10 of FIG. 8. FIG. 11 is a diagram corresponding to FIG.
4 Instrument panel 6 Lid 6 ₁ Tier line 13 Air bag
14 blind holes 16 molds
17 ₅ protrusions 19 skin material (resin skin material)
22 Base material (resin base material)
Rp Airbag device for passenger seat (airbag device)

Claims (2)

A lid (6) provided with a tear line (6 ₁ ) that is provided so as to cover the airbag device (Rp) housed inside the instrument panel (4) and is broken by the pressure of the inflating airbag (13) In the manufacturing method of the lid for the airbag device for manufacturing the
The lid (6) is formed by laminating a resin skin material (19) on the front surface side and a resin base material (22) on the back surface side,
When the resin base material (22) is molded with the mold (16), the rear surface of the resin base material (22) is formed on the cavity line ( 17 ₁ ) on the tear line (6 ₁ ). by using the corresponding plurality of pin-like projection (17 ₅₎ to each other at intervals projected by said mold to (16), on the back side of the resin substrate (22), said tear line ( 6 ₁ ) so as to form a plurality of stepped blind holes (14) that are arranged at a distance from each other to form one piece ,
Each of the pin-shaped protrusions (17 ₅ ) has a large diameter portion that stands up from the cavity surface (17 ₁ ) and a small diameter portion that stands up from the tip of the large diameter portion. A manufacturing method of a lid for an air bag device.   2. The manufacturing of a lid for an airbag device according to claim 1, wherein the resin base material (22) is molded in a state in which a resin skin material (19) is inserted into the mold (16). Method.

Images