CN100999127A - Method for making air bag cover - Google Patents
Method for making air bag cover Download PDFInfo
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- CN100999127A CN100999127A CNA2007100002187A CN200710000218A CN100999127A CN 100999127 A CN100999127 A CN 100999127A CN A2007100002187 A CNA2007100002187 A CN A2007100002187A CN 200710000218 A CN200710000218 A CN 200710000218A CN 100999127 A CN100999127 A CN 100999127A
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- airbag cover
- moulding
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- breaking part
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Abstract
An airbag cover is manufactured by thermoplastic resin for injection moulding in the invention. A prefabricated breaking part is formed by a groove on a back side of the airbag cover. A mould (23) for forming the airbag cover comprises: split dies (24, 25) for forming a die cavity (23a); and a metal plate part (28) for forming a groove part on tail end for prefabricating the breaking part. The plate part (28) with thickness of 0.3mm to 1.5mm protrudes from the tail end to the die cavity (23a) and is fixed on the split die (25) on a root side thereof, via heat insulation materials (29A, 29B). The split die (25) is formed on a position near the groove of the back side of the airbag cover.
Description
Technical field
The present invention relates to a kind of method of making airbag cover, this airbag cover is made by synthetic resin, be suitable for covering folding air bag, and be designed to when being subjected to expanding the air bag roof pressure that launches, split, to form the outstanding opening of using of air bag at this in thin prefabricated breaking part place.
Background technology
In the conventional airbag cover of making by thermoplastic resin, around door portion, form thin prefabricated breaking part, make when lid is subjected to the air bag roof pressure, can beat door opening portion, thereby form the outstanding opening of using.By on the airbag cover rear side, groove being set, it is extended continuously along prefabricated breaking part, thereby form this prefabricated breaking part, and, in routine techniques, in passing through the process of injection moulding molding airbag cover, rear side at two branch moulds that form die cavity is divided on the mould, is provided with to have the roughly protuberance of angular cross section, with corresponding with groove, thereby form prefabricated breaking part (for example, referring to JP-A-2002-103404).
Yet, under the situation that protuberance and branch mould are become one, when the moulding airbag cover, be positioned near the die part of protuberance, make at the moulding material of attenuation with the position of formation prefabricated breaking part, than constituting the prefabricated breaking part moulding material cooling earlier at position on every side, therefore, because resin shrinkage difference, on the front surface side at prefabricated breaking part position on the airbag cover of so moulding, produce shrink mark or lustre lacking uniformity, thereby cause the risk of airbag cover appearance property deterioration.
In order to tackle this problem, a kind of configuration has also been proposed, wherein protuberance is arranged to and the unit that divides mould to separate, the feasible protuberance of when injecting forming material, withdrawing, and after the moulding material injection, protuberance is projected in the die cavity, to form prefabricated breaking part (for example, referring to JP-A-2003-326559).In protuberance,, carry out local heat, form prefabricated breaking part in this way with part to protuberance in conjunction with heater.
Yet, under the situation that adopts the employed conventional mould of moulding airbag cover, need be in protuberance built-in heater, in addition, also need to be used to make the mobile device of protuberance turnover die cavity.So the complex structure of mould causes increasing the production cost of airbag cover.
Summary of the invention
In order to solve the problem that exists in the routine techniques the present invention is proposed, and, the objective of the invention is, a kind of method of making airbag cover is provided, the increase of production cost can be avoided, and near the airbag cover that has the good appearance performance prefabricated breaking part can be manufactured on.
According to the present invention, a kind of method of making airbag cover is provided, this airbag cover is formed through injection moulding by thermoplastic resin, be configured to cover folding air bag, and be designed to when the air bag roof pressure that expanded, make airbag cover in thin prefabricated breaking part place fracture, to form the outstanding opening of using of air bag at this, wherein
Prefabricated breaking part comprises by the position that groove limited that is arranged on the airbag cover rear side, wherein,
The mould that is used for the moulding airbag cover is made up of a plurality of minutes moulds and metal plate shape part, when closure is divided mould, and the die cavity that divides mould to form the moulding airbag cover, and the metal plate shape part forms the groove position of prefabricated breaking part at its end side, and wherein,
The thickness of panel-like member is in 0.3 to 1.5mm scope, and panel-like member is outstanding to die cavity at its end side, and panel-like member is fixed on via heat-insulating material on the branch mould in its root side, this minute mould be used for being positioned on the moulding airbag cover rear side near the position the groove.
In the method for manufacturing airbag cover according to the present invention, owing to adopt such configuration, wherein, form the panel-like member of prefabricated breaking part groove, be fixed on via heat-insulating material on the branch mould in its root side, when the moulding airbag cover, make panel-like member not be subject to divide the mould Temperature Influence on every side, thereby avoid panel-like member to be cooled, thereby and flow between the moulding material in the die cavity and produce the temperature difference.In addition, in the present invention, owing to be configured to panel-like member thinner, make its thickness in 0.3 to 1.5mm scope, and panel-like member is configured to be fixed on the branch mould with such state, make heat-insulating material place between mould and the panel-like member, like this, in case panel-like member contacts with the moulding material that flows to die cavity, easily lingeringly the panel-like member heating is not reached the temperature roughly the same with moulding material, can remain the temperature of temperature that constitutes near the moulding material of the part groove position and the moulding material that constitutes other positions roughly the same.Thus, the moulding material that can avoid constituting the prefabricated breaking part position solidifies early than the moulding material that constitutes other positions, make the former solidify with constituting the former latter's at position curing on every side, thereby can avoid following problem, promptly, owing to produce the resin difference in shrinkage near the front surface position that is positioned on the airbag cover of so moulding the prefabricated breaking part, and cause the generation of shrink mark or lustre lacking uniformity.
Just, in the present invention, only by thin panel-like member (formation prefabricated breaking part) being fixed on the branch mould via heat-insulating material, produce shrink mark or lustre lacking uniformity causes the appearance property deterioration with regard to reducing because of prefabricated breaking part position on the airbag cover of moulding, and the mobile device that does not need the mobile protuberance that adopts in the routine techniques, and be combined in heater in the protuberance, thereby, the mould production cost can be reduced.
Therefore, in the method for manufacturing airbag cover according to the present invention, can make the airbag cover that can reduce production costs, and near the part of this airbag cover prefabricated breaking part shows good design performance.Certainly, make in the method for airbag cover in the present invention, make the panel-like member thickness that forms groove in 0.3 to 1.5mm scope, and, because the rapid attenuation in groove position of prefabricated breaking part on this feasible airbag cover that produces, so, when air bag is expanded, be easy to generate stress and concentrate, thereby, guarantee the smooth and easy fracture of prefabricated breaking part.
In addition, in the manufacture method of this airbag cover, airbag cover preferably is configured to have a portion, and this one can cover the outstanding opening of using, and, can open by the air bag roof pressure,
Prefabricated breaking part preferably includes the cross part that intersects with the groove position, makes groove position and cross part be arranged to the mode on every side around door portion,
Mould preferably has such cast gate, and moulding material is expelled in the die cavity from this cast gate, and the moulding material stream that flows in die cavity when making moulding is advanced along the direction that is provided with of panel-like member, and
Preferably cross part is formed on on the formed in mould moulded products by post processing.
In the manufacture method of airbag cover of configuration as mentioned above, when injecting forming material, improved near moulding material flowing panel-like member, even the position of prefabricated breaking part is thinner, also moulding airbag cover easily and can moulding not bad.
In addition, in the manufacture method of this airbag cover, airbag cover is comprised under the situation of sidewall, at near the position that is arranged on the airbag cover rear side prefabricated breaking part groove, this sidewall is arranged to extend along the groove position of prefabricated breaking part, so that sidewall covers the side of folded airbag with the housing that holds folded airbag therein, and, heat-insulating material is set to produce difference on level height, make the position that is positioned on sidewall one side in the heat-insulating material deeper be projected into die cavity than the position that is positioned on its opposite side, by means of at the side-prominent heat-insulating material of sidewall one, can firmly support panel-like member, and on the panel-like member opposite side of giving prominence to less heat-insulating material side, increase the area that exposes of the relative moulding material of panel-like member, and moulding material flows under the situation of die cavity when the moulding airbag cover, can heat panel-like member quickly.
Description of drawings
Fig. 1 illustrates the shaft side figure of user mode therapeutic method to keep the adverse qi flowing downward operculum, and this airbag cover adopts and makes according to the manufacture method of one embodiment of the present invention;
Fig. 2 uses the cutaway view of the airbag apparatus of present embodiment airbag cover, for Fig. 1 in the corresponding cutaway view in position of II-II line;
Fig. 3 illustrates near the partial enlarged drawing the portion of going out, and is the being seen airbag cover view from the airbag cover bottom side;
Fig. 4 is the cutaway view of the airbag cover of present embodiment, and is corresponding with the position of IV-IV line among Fig. 3;
Fig. 5 is the cutaway view of the airbag cover of present embodiment, and is corresponding with the position of V-V line among Fig. 3;
Fig. 6 is the cutaway view of the airbag cover of present embodiment, and is corresponding with the position of VI-VI line among Fig. 3;
Fig. 7 is the local longitudinal sectional view of mould under user mode that diagram is used for moulding present embodiment airbag cover;
Fig. 8 is the plane of the panel-like member that uses in the mould of present embodiment;
Fig. 9 (Fig. 9 A, Fig. 9 B) is a schematic diagram, the prefabricated breaking part forming processes of carrying out when being shown in the airbag cover of making present embodiment;
Figure 10 is the upward view of the airbag cover of present embodiment;
Figure 11 (Figure 11 A to Figure 11 D) is the plane that diagram is used for the modification of the panel-like member that the mould of airbag cover of moulding present embodiment uses;
Figure 12 A and Figure 12 B are schematic diagrames, the airbag cover that diagram is made with the manufacture method of another example of the present invention.
The specific embodiment
Below, embodiments of the present invention are described with reference to the accompanying drawings.As shown in Figure 1 and Figure 2, the airbag cover 10 of Zhi Zaoing in the present embodiment, be used for being seated at the passenger of front passenger seat (front passenger's seat) or the airbag apparatus S that the occupant uses, (comprise thermoplastic resin by synthetic resin, such as olefin-based thermoplastic elastomer) by the injection moulding manufacturing, and be set in place in the opening 2b of the instrument board upside 2a in front occupant seat the place ahead.
It should be noted that, be installed on the motor vehicle by design based on airbag cover 10, " vertical " of Shi Yonging, " vertically " and " laterally " in this manual, consistent with motor vehicle " vertical ", " vertically " and " laterally " of motor vehicle of keeping straight under the state to overtake.
In addition, the airbag apparatus S that is used for the front stall occupant comprises: folding air bag 4; Aerator 7 is used for providing expanding gas to air bag 4; Housing 8 holds and keeps air bag 4 and aerator 7; Retainer 5 is used for air bag 4 is installed in the appropriate location of housing 8; And airbag cover 10 covers folding air bag 4.
When complete expansion, 4 one-tenth in air bag is quadrangular pyramid shape roughly, and wherein the front of air bag constitutes the top of taper, and constitutes the rear surface side at the bottom of the air bag of conical lower portion, constitutes occupant's restriction portion.In the time of on being installed in motor vehicle; in order to take in; this air bag 4 is folding to the upside 2a of the instrument board 2 that is positioned at front occupant seat front side; and when expanding gas flows to wherein; air bag 4 projects upwards; with the upside 2a that covers at instrument board 2 be arranged on the space that limits between the windshield above the instrument board 2, outstanding backward simultaneously, in order to the protection front stall occupant of occupant's restriction portion who is used on the face side thereafter.
In addition, aerator 7 comprises: roughly columned main part 7a has a plurality of gas outlet 7b; And flange part 7c, via flange part 7c aerator 7 is installed on the housing 8.
In addition, housing 8 forms roughly cuboid, and distolateral thereon have a rectangular aperture, and form by tabular bottom wall portion 8a of essentially rectangular and surrounding wall portion 8b, aerator 7 passes bottom wall portion 8a being installed on bottom wall portion 8a from the below, and surrounding wall portion 8b extends upward from bottom wall portion 8a outer peripheral edges.Form a plurality of lock pawl 8c in the upper end of surrounding wall portion 8b, be used to lock the side wall portion 20 of airbag cover 10.Place, bottom wall portion 8a position is provided with support 8d on housing 8, to be connected with the vehicle body 1 of motor vehicle.
In addition, with being arranged on a plurality of bolt 5a of the annular retainer 5 in the air bag 4, pass the periphery 4b of air bag 4 split shed 4a, the flange part 7c and the 8a of shell bottom wall portion of aerator 7, with corresponding nut 6 that it is fastening, thereby, air bag 4 and aerator 7 are installed on the housing 8.
Give prominence to and form rectangular plate shape with peristome 12, and constitute such position: by making former and later two ones, door portion 13 and door portion 14 open forward and backward respectively, are formed for the rectangular aperture 12a that air bag 4 is given prominence to.When being opened, to be arranged in the outstanding articulated section, front side 15 of peristome 12 front edge sides of using as center of rotation, door portion 13 is to front opening when upwards rotating around articulated section, front side 15, simultaneously, when being opened, to be arranged in the outstanding articulated section 15 of using peristome 12 trailing edge sides as center of rotation, door portion 14 opens backward when upwards rotating around rear side articulated section 15.Above-mentioned articulated section 15 is arranged among the front wall portion 20a and the position on the rear wall parts 20b inner surface of side wall portion 20.
In addition, to shown in Figure 6, form prefabricated breaking part 16 as Fig. 1, when air bag 4 expanded, prefabricated breaking part 16 was suitable for rupturing because of the roof pressure of air bag 4.By groove being set continuously in outstanding rear side with peristome 12, form this prefabricated breaking part 16, and, under the situation of present embodiment, this prefabricated breaking part 16 is provided with: two groove position 16b, 16b,, be arranged as with on the left and right sides both end sides of peristome 12 outstanding with the linear fashion longitudinal extension; And cross part 16a, with the linear fashion horizontal expansion, connecting, when the top is watched, groove position 16b, 16b and cross part 16a are arranged as in groove position 16b, 16b longitudinal middle part position, form roughly H shape.Groove position 16b, 16b are set in place near the left wall 20c of portion of side wall portion 20 and the right wall 20d of portion inner surface the position.Under the situation of present embodiment, can after airbag cover 10 moulding,,, form cross part 16a with the cutter cutting along the boundary position between door portion 13, the door portion 14.
Extremely shown in Figure 6 as Fig. 4, each one 13,14 is changed on thickness gradually, its mode is, along whole peripheries (arranging articulated section 15 and prefabricated breaking part 16) in perimembranous, reduce towards all edge thickness, make to be positioned near the side wall portion 20 outstanding thickness t 4 (referring to Fig. 4, Fig. 5) with peristome 12 positions, roughly the same with the thickness t 2 (referring to Fig. 4, Fig. 5) of side wall portion 20.Be positioned near the prefabricated breaking part 16 groove position 16b outstanding with peristome 12 positions, make the position between groove position 16b and side wall portion 20 thinner than the position of door portion 13,14 sides, on level height, to form difference, make the position between groove position 16b and the side wall portion 20 have minimum thickness, take this, make the thickness t 4 of corresponding site roughly the same with the thickness t 2 of side wall portion 20.In addition, to shown in Figure 6, along the position of side wall portion 20 peripheries, the thickness of circumference 18 changes gradually in circumference 18 as Fig. 4, make it to side wall portion 20 side attenuates, make that near the thickness t 3 (referring to Fig. 4, Fig. 5) at side wall portion 20 positions is roughly the same with the thickness t 2 of side wall portion 20.Adopt this configuration, avoiding the deterioration of airbag cover 10 appearance properties, this deterioration be because, during injection moulding airbag cover 10 moulding material shrink variant, thereby near the airbag cover 10 front surface sides that are positioned at the side wall portion 20 generation shrink mark etc.
In the airbag cover 10 of present embodiment, the thickness t 1 at door portion 13,14 and circumference 18 thicker positions is set in 3.0 to 4.0mm scopes, and the thickness t 2 of side wall portion 20 (front side wall portion 20a, rear side wall portion 20b, the 20c of left side wall portion and right side wall portions 20d) is set in 2.0 to 3.0mm scopes.In addition, be positioned near the thickness t 3 at circumference 18 positions the side wall portion 20 and thickness t 4 (being positioned near the thickness at door portion 13,14 positions the side wall portion 20) and be set in 2.0 to 3.0mm scopes.Make the groove position 16b of prefabricated breaking part 16 form thickness in the following manner and gradually change, make at the otch at longitudinal middle part place the deeplyest, and shoal to the rear and front end side of groove position 16b.Just, top wall portion 11 is configured to, in the thickness minimum of the surplus part of institute at place, its longitudinal center position, simultaneously, to its rear and front end side thickness increase.Under the situation of present embodiment, groove position 16b is configured to, and for the thickness t 5 (referring to Fig. 5) of 11 surplus parts of top wall portion, at place, longitudinal center position, t5 is in 0.8 to 1.2mm scope, and in the rear and front end side, t5 is in 1.5 to 2.0mm scopes.In addition, the cross part 16a of prefabricated breaking part 16 forms thickness and gradually changes in the following manner, makes at the otch at lateral middle place the deeplyest, and shoals to its left and right sides both end sides.Just, top wall portion 11 is configured to, the thickness of surplus part in lateral middle position minimum, increase to its left and right sides both end sides thickness simultaneously.Under the situation of present embodiment, cross part 16a forms the thickness t 6 (referring to Fig. 4) of 11 surplus parts of top wall portion in 0.8 to 1.4mm scope.
Using mould 23 during according to present embodiment airbag cover 10 by the injection moulding manufacturing, as shown in Figure 7, this mould 23 is made up of two branch moulds 24,25 and panel-like member 28, divide mould 24,25 to open and close (when the moulding implemented according to present embodiment along the vertical direction of institute's moulding airbag cover 10, in fact divide mould to open and close in the horizontal direction), panel-like member 28 forms the groove position 16b of prefabricated breaking part 16.The die face 24a that divides mould 24 to comprise moulding airbag cover 10 front surface sides, and, divide mould 25 to comprise the die face 25a of moulding airbag cover 10 rear side.In addition, divide mould 25 to be configured to, suitably separated by the core (not shown).
Panel-like member 28 is made for and the parts that divide mould 25 to separate, and is made such as high nickel steel by metal.By following mode panel-like member 28 is fixed on the branch mould 25 in its root 28b side, makes its terminal 28a side be projected into the die cavity 23a from minute mould 25.Under the situation of present embodiment, as shown in Figure 8, panel-like member 28 forms plate shaped, the distolateral linearity that forms of this plate shaped elder generation, and roughly along continuous straight runs extends.In addition, the gauge t7 (referring to Fig. 7) of panel-like member 28 is set in 0.3 to 1.5mm scope (0.4 to 0.7mm scope ideally).Under the situation of present embodiment, the gauge t7 of panel-like member 28 is set at 0.5mm.
The root 28b side of panel-like member 28 is kept by plate shape heat-insulating material 29A, 29B, and, via heat-insulating material 29A, 29B panel-like member 28 is fixed on the branch mould 25.Under the situation of present embodiment, heat-insulating material 29A, 29B are made by phenolic resins etc., and the two all is set at the gauge t8 (referring to Fig. 7) with 1mm level.Should be noted that under the situation of present embodiment,, also can use heat-insulating material as heat-insulating material 29A, 29B with different-thickness size although heat-insulating material 29A, 29B use the heat-insulating material that gauge t8 is set in same thickness.In addition, heat-insulating material 29A, 29B are set to keep betwixt panel-like member 28, simultaneously, between the level height of heat-insulating material 29A, 29B or projecting degree, difference is set in such a way, makes the heat-insulating material 29A that is arranged in side wall portion 20 sides deeper be projected into die cavity 23a than the heat-insulating material 29B that is positioned at a portion 13,14 sides.Under the situation of present embodiment, 29A is arranged as with heat-insulating material, deeper is projected among the die cavity 23a than heat-insulating material 29B with the degree of 1mm.
In addition, although in the present embodiment, because of having high strength and excellent toughness, high nickel steel forms panel-like member 28 with high nickel steel, but because panel-like member 28 is made thinlyyer, and its state that is clipped in the middle is fixed on the branch mould 25 with heat-insulating material 29A, 29B, so, easily panel-like member 28 is heated to the roughly the same temperature of moulding material M that contacts with panel-like member 28, and on temperature, does not allow to be subject to divide the influence of mould 25 on every side.In addition, during the injection moulding to applying near the panel-like member 28 under the situation of impact, the heat-insulating material 29A around the panel-like member 28, the effect that 29B plays padded coaming, thereby, can avoid excessive impact to be applied on the panel-like member 28.Thus, can make panel-like member 28 by such material, the pyroconductivity that this material has is roughly more than or equal to the pyroconductivity (0.18cal/cms ℃) of iron, and has 200 (H
B) level or higher hardness, so panel-like member can be formed by metal material such as steel (comprising, for example frame for movement carbon steel, chrome-molybdenum steel, pre-hardened steel etc.).
Under the situation of present embodiment, at circumference 18 positions (referring to Fig. 2, Figure 10) that are arranged in side wall portion 20 20c of left and right sides wall portion, 20d (groove position 16b, the 16b of prefabricated breaking part 16) front cast gate 23b is set, moulding material M is expelled to the die cavity 23a from cast gate 23b.Because this configuration, when when being arranged in the cast gate 23b injecting forming material M of these positions, under the situation of present embodiment, as shown in figure 10, so the moulding material M of injection along roughly vertically (promptly along the groove position 16b of prefabricated breaking part 16 extend vertically) side flow backward from the front side of mould 23.Just, moulding material M flows along the direction (along the direction of panel-like member 28) that intersects with approximate right angle and mould shown in Figure 7 23 cross sections.
The airbag cover 10 of present embodiment can be by following step moulding: close die 23, moulding material M is injected into die cavity 23a from cast gate 23b, finish filling with moulding material M to die cavity 23a, moulding material M is solidified in mould 23, open mould 23, and from the mould of opening like this 23, take off the moulding section of airbag cover 10.Afterwards, as shown in Figure 9, use ultrasonic wave cutter C to form the cross part 16a of prefabricated breaking part 16, make airbag cover 10.Should be noted that as the machining tool that is used to form cross part 16a, except ultrasonic wave cutter C, can also use laser cutting tool, cold chisel etc., in addition, also can use the thin rod shape slotting cutter to form cross part 16a.
Then, when the airbag cover 10 of moulding like this is installed on the motor vehicle as the parts of airbag apparatus S, airbag cover 10 is placed on above the air bag component, in air bag component, utilize bolt 5a and nut 6, to hold the folded airbag 4 of retainer 5 and aerator 7 and hold and remain on appropriate position in the housing 8, and lock pawl 8c is locked on the periphery of lock hole 20e.Afterwards, will assemble the air bag component of airbag cover 10, the opening 2b from the instrument board 2 injects in the instrument board 2 that is installed in advance on the motor vehicle, and, locking pillar 18a is locked on the opening periphery 2c, the support 8d of housing 8 is fastened on vehicle body 1 side.In addition, when air bag circuits for triggering extension lead-in wire is connected to aerator 7, airbag apparatus S is installed on the motor vehicle, by this lead-in wire input predetermined trigger signal.
When trigger gas bag apparatus S; expanding gas from aerator 7 flows in the air bag 4; make its expansion then; the air bag 4 fierce roof pressures that expand are outstanding with peristome 12; thereby make prefabricated breaking part 16 fractures, and the door portion 13,14 of airbag cover 10 is opened respectively forwards, backwards, it is outstanding largely outstanding with opening 12a to make that air bag 4 can form when door portion opens like this; expand to finish it, thereby protection is seated at the occupant of front occupant seat.
In addition, making according to present embodiment in the method for airbag cover 10, because form the panel-like member 28 of prefabricated breaking part 16 groove position 16b, be fixed on the branch mould 25 via heat-insulating material 29A, 29B in root 28b side, so when moulding airbag cover 10, panel-like member 28 is difficult to be subjected to the Temperature Influence that panel-like member 28 divides mould 25 on every side, thereby, just can avoid on temperature, producing difference between moulding material M in the die cavity 23a and the panel-like member 28 self and causing panel-like member 28 coolings owing to flowing to.In addition, in the present embodiment, because panel-like member 28 is set at gauge t7 in 0.3 to 1.5mm scope (ideally, from 0.4 to 0.7mm scope), and make it via heat-insulating material 29A, 29B is fixed on the branch mould 25, so, under panel-like member 28 and situation that moulding material M in flowing to die cavity 23a contacts, easily panel-like member 28 is heated to the roughly the same temperature of moulding material M without any delay, to guarantee the avoiding panel-like member temperature sharply to change, thereby, can be with the temperature maintenance of temperature that constitutes near the moulding material M the groove position 16b and the moulding material M that constitutes airbag cover 10 other positions for roughly the same each other.Thus, avoid constituting the moulding material of groove position 16b than the more Zao curing of moulding material of forming other positions of airbag cover, and it can be solidified with the moulding material that constitutes airbag cover peripheral part, thereby, just can avoid because resin shrinkage difference, cause in the airbag cover 10 of so moulding, being positioned near the front surface side its prefabricated breaking part 16 inhomogeneous on generation shrink mark or the gloss.
Just, in the present embodiment, only be fixed on the branch mould 25 via heat-insulating material 29A, 29B by the panel-like member 28 that will form prefabricated breaking part 16, the airbag cover prefabricated breaking part 16 (groove position 16b) that just can reduce in moulding is located to cause airbag cover appearance property deterioration owing to producing shrink mark or lustre lacking uniformity, therefore, do not need to be used for the mobile device of mobile protuberance in the routine techniques and to be combined in the heater of protuberance, and can reduce the mould production cost.
Therefore, in method, can reduce the input of production cost according to the manufacturing airbag cover 10 of present embodiment, and, can be manufactured near the airbag cover 10 that presents the good appearance performance prefabricated breaking part.Certainly, in method according to the manufacturing airbag cover 10 of present embodiment, panel-like member 28 forms the side slat shape position 16b that respectively has groove shapes, this panel-like member 28 has 0.3 to 1.5mm thickness, so that the rapid attenuation of side slat shape position 16b of prefabricated breaking part 16, so, stress is concentrated easily taken place, to guarantee the smooth and easy fracture of prefabricated breaking part 16.
In addition, in the present embodiment, moulding material M is injected into the die cavity 23a from cast gate 23b, cast gate 23b is arranged in such a way in the position that is arranged in 16b front, prefabricated breaking part 16 groove position, make moulding material M flow among the die cavity 23a along the direction that is provided with of panel-like member 28, when moulding airbag cover 10, integral way shaping groove position 16b, and, after airbag cover 10 moulding, form cross part 16a by post processing, the mode that this cross part 16a intersects with the injection direction with moulding material M is arranged in the prefabricated breaking part 16.Thus, when injecting forming material M, improved near moulding material M flowing panel-like member 28, even it is thinner to form the position of groove position 16b, also moulding airbag cover easily 10, and forming defect can not occur.Certainly,, utilize the mode of wherein intersecting that the mould of panel-like member is set, also can make airbag cover with injection direction with moulding material unless consider this point.In addition, although in the present embodiment, cast gate 23b (moulding material M is expelled among the die cavity 23a thus) is arranged in the position of left and right sides side wall portion 20c, 20d (the groove position 16b) front of side wall portion 20, but, the position of cast gate 23b is not to be limited in above-mentioned position, therefore, cast gate 23b can be arranged in left and right sides side wall portion 20c, 20d (groove position 16b) back location, perhaps, can adopt following configuration, wherein only near the position the transverse center of leading edge that is positioned at airbag cover or trailing edge side is provided with single cast gate.
In addition, in the present embodiment, because will be positioned at the heat-insulating material 29A of side wall portion 20 sides is arranged as, make himself and be positioned at a portion 13, between the heat-insulating material 29B of door portion 14 sides level height or outstanding on produce difference, make heat-insulating material 29A deeper be projected among the die cavity 23a than heat-insulating material 29B, can firmly support panel-like member 28 by the heat-insulating material 29A that gives prominence in side wall portion 20 sides, and give prominence to the area that exposes that increases by 28 couples of moulding material M of panel-like member on the less opposition side at heat-insulating material 29B, thereby when moulding airbag cover 10, when flowing among the die cavity 23a, can heat panel-like member 28 quickly as section bar material M.In addition, because near the thickness at side wall portion 20 positions that are provided with prefabricated breaking part 16 groove position 16b is reduced, and this position is to form in the recessed mode of its rear side, make the thickness at this position and the consistency of thickness of side wall portion 20, and the thickness of side wall portion 20 forms De Bimen portion 13, door portion 14 usually and circumference 18 is thin, to improve the appearance property of manufacturing airbag cover 10, utilize recessed position, can arrange heat-insulating material 29A and without any problem in the mode that is projected into die cavity 23a.
In addition, although in the present embodiment, panel-like member 28 adopts terminal 28a side to form roughly rectilinear panel-like member, but the shape of this panel-like member is not limited thereto, so, for example, shown in Figure 11 A to Figure 11 D, can use following panel-like member, as: panel-like member 28A, its terminal 28a side forms the shape with zigzag projection; Panel-like member 28B, its terminal 28a side forms interval mode pointed shape is set; Panel-like member 28C, its terminal 28a side forms the shape with gear teeth stripping and slicing; Perhaps, panel-like member 28D, its terminal 28a side forms the shape with continuous semicircular arc.It should be noted that, be provided with under the situation of panel-like member 28A to 28D of concaveconvex shape using in its terminal 28a side, outstanding position with the groove position 16b that forms prefabricated breaking part 16 from minute mould 25, the employed concaveconvex shape position that is positioned at terminal 28a side, with all the other positions that are positioned at root 28b side, its length preferably is set in 1: 1 to 2: 1 scope than L1: L2 (referring to Figure 11 A).
It should be noted that, although preamble is that present invention is described for example with airbag cover 10, this airbag cover 10 has two door portions 13 arranging in the parallel longitudinal mode, door portion 14 and becomes the roughly prefabricated breaking part 16 of H shape in door portion 13, door portion 14 arranged around, but the shape of the door portion of airbag cover is not limited thereto, so, for example, the present invention can be applied to such airbag cover, the door portion that it had, has only single door portion, around this one, be furnished with horizontal or inverted U-shaped prefabricated breaking part.In addition, the present invention can be applied to this airbag cover, and it does not arrange a portion, and has only the single straight line prefabricated breaking part of arranging along predetermined position.
In addition, when forming cross part 16a, use under the situation of the ultrasonic wave cutter C as shown in the enforcement mode with monocline cutoff edge, shown in Figure 12 A and Figure 12 B, for airbag cover 10A, near the processing terminal 16aa of the cross part 16a that is arranged in formation like this position, can be in the side-prominent mode of the 20d of wall portion to the right, form blade edge point accommodation section 16c continuously with groove position 16b, blade edge point accommodation section 16c holds the taper of the knife edge of the ultrasonic wave cutter C that is used to form cross part 16a.Accommodation section 16c is configured to this blade edge point, when forming the terminal 16aa of cross part 16a, the taper that can hold the knife edge of ultrasonic wave cutter C, and, if adopt the configuration that this blade edge point accommodation section 16c wherein is set, when forming the terminal 16aa of cross part 16a, can avoid forming the otch of unnecessary cross grooves position 16b.As a result, when air bag 4 expands expansion, because the fracture of cross part 16a is no more than groove position 16b, so, formed prefabricated breaking part 16 is ruptured in smooth and easy mode.Should be noted that when forming airbag cover 10A, to form this blade edge point accommodation section 16c, perhaps, can after airbag cover 10A moulding, form blade edge point accommodation section 16c by using slotting cutter to carry out post processing with injection moulding.
In addition, although in the present embodiment, described this airbag cover 10, it forms as the parts that separate with instrument board 2, and as the part of front stall occupant airbag apparatus S, the present invention also can be applied to the airbag cover with the moulding of instrument board integral way.In addition, the present invention can be applied to be the airbag cover operator's seat setting or that be arranged on the airbag apparatus of seat side.
Claims (3)
1. method of making airbag cover, this airbag cover is formed through injection moulding by thermoplastic resin, be configured to cover folding air bag, and be designed to when the described air bag roof pressure that expanded, make described airbag cover in thin prefabricated breaking part place fracture, to form the outstanding opening of using of described air bag at this
Wherein, described prefabricated breaking part comprises by the position that groove limited that is arranged on the described airbag cover rear side,
Wherein, the mould that is used for the described airbag cover of moulding is made up of a plurality of minutes moulds and metal plate shape part, when described minute mould of closure, described minute mould is formed for the die cavity of the described airbag cover of moulding, and described metal plate shape part forms the groove position of described prefabricated breaking part at its end side, and
Wherein, the thickness of described panel-like member is 0.3mm to 1.5mm, described panel-like member is outstanding to described die cavity at its described end side, and, described panel-like member is fixed on via heat-insulating material on the branch mould in its root side, this minute mould be used for being positioned on the described airbag cover rear side of moulding near the position the described groove.
2. the manufacture method of airbag cover according to claim 1, wherein said airbag cover is constructed with a portion, and this one can cover the described outstanding opening of using, and, can open by described air bag roof pressure,
Wherein, the cross part that described prefabricated breaking part comprises and intersect at described groove position makes described groove position and described cross part be arranged to around described door portion,
Wherein, described mould has cast gate, and moulding material is expelled in the described die cavity from described cast gate, and the moulding material stream that flows in described die cavity when making moulding is advanced along the direction that is provided with of described panel-like member, and
Wherein, by post processing, on described formed in mould moulding section, form described cross part.
3. according to the manufacture method of claim 1 or the described airbag cover of claim 2, wherein, described airbag cover comprises sidewall, near the groove that is arranged in described prefabricated breaking part on the described airbag cover rear side position, described sidewall is arranged to extend along the groove position of described prefabricated breaking part, so that described sidewall covers the side of described folded airbag with the housing that holds described folded airbag therein, and
Wherein, described heat-insulating material is set to be provided with the height plane difference, makes the position that is positioned at described sidewall one side in the described heat-insulating material deeper be projected into described die cavity than the position that is positioned at its opposite side.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006003910A JP4677904B2 (en) | 2006-01-11 | 2006-01-11 | Manufacturing method of airbag cover |
| JP2006003910 | 2006-01-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN100999127A true CN100999127A (en) | 2007-07-18 |
| CN100534756C CN100534756C (en) | 2009-09-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2007100002187A Active CN100534756C (en) | 2006-01-11 | 2007-01-11 | Method for making air bag cover |
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| Country | Link |
|---|---|
| JP (1) | JP4677904B2 (en) |
| CN (1) | CN100534756C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103038103A (en) * | 2011-07-19 | 2013-04-10 | 丰田自动车株式会社 | Airbag device for front passenger seat |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5050731B2 (en) * | 2007-08-23 | 2012-10-17 | トヨタ紡織株式会社 | Groove formation method |
| JP7488515B2 (en) | 2021-07-12 | 2024-05-22 | 豊田合成株式会社 | Airbag cover |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1076555A (en) * | 1996-09-05 | 1998-03-24 | Tohoku Munekata Kk | Method for injection molding of plastic molded article with partly thin part and mold used for injection molding |
| JP3708825B2 (en) * | 2001-01-15 | 2005-10-19 | 西川化成株式会社 | Airbag door molding method |
| JP2005075140A (en) * | 2003-08-29 | 2005-03-24 | Inoac Corp | Predetermined breaking part in airbag door and its molding method |
| JP2005153259A (en) * | 2003-11-25 | 2005-06-16 | Toyota Auto Body Co Ltd | Method and apparatus for forming matter made of synthetic resin having bottomed groove |
-
2006
- 2006-01-11 JP JP2006003910A patent/JP4677904B2/en active Active
-
2007
- 2007-01-11 CN CNB2007100002187A patent/CN100534756C/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103038103A (en) * | 2011-07-19 | 2013-04-10 | 丰田自动车株式会社 | Airbag device for front passenger seat |
| CN103038103B (en) * | 2011-07-19 | 2014-01-08 | 丰田自动车株式会社 | Airbag device for front passenger seat |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100534756C (en) | 2009-09-02 |
| JP4677904B2 (en) | 2011-04-27 |
| JP2007185797A (en) | 2007-07-26 |
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