JP4582006B2 - Manufacturing method of airbag cover - Google Patents

Description

  The present invention includes a thinly-scheduled breakable portion that extends in a linear shape that covers a folded airbag and that can be pushed by an inflating airbag to break and form a projecting opening that projects the airbag. The present invention relates to a synthetic resin airbag cover formed by molding.

Conventionally, in an air bag cover made of synthetic resin, when the air bag is pushed, a door portion is opened to form a protruding opening, so that a thin breakage planned portion is formed around the door portion. (For example, refer to Patent Document 1). This rupture-scheduled part is configured with a concave groove on the back side of the injection-molded airbag cover, and it can be further processed by an optical measuring instrument so that it can be processed with increased dimensional accuracy of position and depth. The position and depth of the processing line are measured in advance, and the groove is formed by a slitting process using a cutting blade of a processing tool such as an ultrasonic cutter.
JP 2005-289254 A

  However, when the scheduled breakage portion of the airbag cover is formed by cutting, there is room for improvement in terms of eliminating variations in the position and depth of the cut. That is, if there is a large variation in the position or depth of the cut, smooth breakage of the portion to be broken at a low temperature such as −20 ° C. is hindered.

  The present invention solves the above-described problems, and an object of the present invention is to provide an airbag cover that can be manufactured while suppressing variations in the position and depth of the cut.

An airbag cover according to the present invention covers a folded airbag, and is a thin-walled rupture schedule that extends linearly so that it can be pushed by an inflating airbag to break and form a protruding opening that protrudes the airbag Part, made of synthetic resin formed by molding,
The air bag cover that is formed by making a groove-like cut by the cutting edge of the processing tool with respect to the back side of the cover material after molding,
A cutting blade storage portion formed by recessing the cutting blade of the processing tool so that the cutting blade of the processing tool can be stored is provided at positions of a start end and a terminal end of the cover material when the cut is processed.

  In the airbag cover according to the present invention, when a cut is made in the cover material to form the portion to be broken, the cutting blade of the processing tool is inserted and arranged in the cutting blade storage portion that is the starting end of the cut, and then added. If the tool is moved to reach the cutting edge storage portion at the end of the cut, it is possible to form a cut that constitutes the planned fracture portion. That is, the start end and the end of the cut are specified in advance as the cutting blade storage portion from the time of molding, and the arrangement position accuracy of the cut can be improved. In addition, even if the depth of the cut is measured in advance by measuring the cutting blade storage portion and its periphery with a measuring instrument such as an optical system, the depth of the cut can be easily adjusted, and the depth accuracy of the cut can be increased. It is possible to improve and operate the processing tool.

  Therefore, in the airbag cover according to the present invention, it is possible to manufacture the planned fracture portion while suppressing variations in the position and depth of the cut.

  And it is desirable for the cutting blade storage part to store the cutting blade of the processing tool without making a cut, and to arrange the deepest part deeper than the cut. In such a configuration, unnecessary cuts are not formed in the cutting blade storage portion, and when the planned breakage portion is broken by being pushed by the airbag, the breakage proceeds from the cutting blade storage portion to an unscheduled portion. Can be prevented.

  In addition, when the planned break portion is configured to include a T-shaped crossing portion that crosses the crossing side portion in a plan view with respect to one linear portion, the cutting blade storage portion is It is desirable to dispose at both ends of the linear portion and also at both ends of the intersecting portion so as to include the T-shaped intersection. In such a configuration, even if the crossing side portion of the planned breaking portion is pushed by the airbag and the breakage proceeds toward the straight portion, the groove is disposed at the T-shaped crossing portion. It can be stopped without exceeding the cutting blade storage portion at the position of the inner peripheral surface of the cutting blade storage portion that is recessed with a width dimension wider than the shape of the cut. That is, it is possible to prevent unnecessary fragments of the airbag cover from being scattered without unnecessarily extending the break.

In the method for manufacturing an airbag cover according to the present invention, a thin-walled wire that covers a folded airbag and that can be formed into a projecting opening that is pushed by the inflating airbag and breaks to project the airbag. It is made of a synthetic resin formed by molding,
The method for manufacturing an airbag cover, in which the planned break portion is formed by making a groove-like cut by a cutting blade of a processing tool with respect to the back side of the cover material after molding,
A cutting blade storage portion for storing the cutting blade of the processing tool is formed in advance at the time of mold forming at the start and end positions at the time of processing the cut in the cover material,
The line to be cut by the processing tool is measured in advance, including the positions of the start and end points where the cut is made, and controlled based on the measured position data, so that the processing tool forms a cut. It is characterized by that.

  In the manufacturing method of the airbag cover according to the present invention, when measuring the line to be cut by the processing tool in advance, including the positions of the start and end of entering the cut, the start and end of entering the cut, Since it is possible to measure with reference to the part of the cutting blade storage part that is recessed from the periphery, it is easy to measure the position data of the cut, and by measuring the cutting blade storage part and its periphery, the depth of the cut The thickness can be easily adjusted, and as a result, the cuts that form the planned breakage are not affected by the displacement due to the thermal expansion of the cover material that depends on the temperature during processing or the displacement of the cover material during processing set. The airbag cover can be manufactured by improving the accuracy of the arrangement position and the depth.

  And, if a wrinkle pattern is formed in the vicinity of the part to be broken, including the periphery of the cutting blade storage part, measurement of an optical system such as a laser displacement meter is performed compared to the case where the wrinkle pattern is not formed. When measuring the planned line of the cut using the device, since it does not reflect like a mirror surface, the planned line can be easily measured with less error. If the textured irregularities are steps of several to several tens of μm, it is possible to easily manage the accuracy of the depth of the cut with an error within ± 0.1 mm.

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

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

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

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

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

  Further, the case 8 is formed in a substantially rectangular parallelepiped shape made of a sheet metal having a rectangular opening on the upper end side, and a substantially rectangular plate-like bottom wall portion 8a to which the inflator 7 is inserted from below and attached, and the bottom wall portion 8a. And a plurality of locking claws 8c for locking the side wall 33 of the airbag cover 10 are formed at the upper end of the peripheral wall 8b. . The case 8 is provided with a bracket 8d connected to the body 1 side of the vehicle at the bottom wall 8a.

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

  As shown in FIGS. 1 to 5, the airbag cover 10 has a rectangular plate-like ceiling wall portion 11 so as to close the opening 2 a of the instrument panel 2, and a substantially square extending downward from the lower surface (back surface) side of the ceiling wall portion 11. And a cylindrical side wall portion 33. A plurality of locking holes 33e are formed in the front and rear wall portions 33a and 33b of the side wall portion 33 to lock the periphery of the locking claw 8c of the case peripheral wall portion 8b. The side wall portion 33 is a portion that covers the periphery of the folded airbag 4 together with the case peripheral wall portion 8b.

  The ceiling wall portion 11 is configured to include a protruding opening portion 12 disposed at a portion surrounded by the side wall portion 33 and a peripheral edge portion 31 around it. A plurality of locking legs 31 a formed on the opening peripheral edge 2 b are provided on the peripheral edge 31 so as to eliminate rattling when the airbag cover 10 is disposed so as to close the opening 2 b of the instrument panel 2. Projected.

  The protruding opening 12 has a rectangular plate shape and is provided with a thin portion to be broken 16 extending linearly. The breakable portion 16 is formed by providing a concave groove 16a that is recessed from the back surface side to the front surface side of the airbag cover 10, and in the case of the embodiment, the intersecting side portion 19 is flat with respect to the straight portions 17 and 18. The T-shaped intersecting portions 20 that intersect in a T-shape in a visual state are arranged at two locations, and the shape in plan view is an H-shape. Therefore, when the planned breakage portion 16 is broken, the front and rear two door portions 13 and 14 with the intersecting side portion 19 in between are opened on both the front and rear sides to form a rectangular opening 12a for protruding the airbag 4. It becomes. The door 13 at the time of opening opens to the front side while turning upward, with the hinge portion 15 disposed on the front edge side as the rotation center, and the door 14 at the time of opening, with the hinge portion 15 on the rear edge side as the rotation center, It will open to the rear side while heading upward. Each hinge portion 15 is a portion connecting the opposite ends in the left-right direction of the vertical bar portions (linear portions 17 and 18) on both sides of the H-shape, on the inner side surfaces of the wall portions 33a and 33b before and after the side wall portion 33. In place.

  In the case of the embodiment, the concave groove 16a of the planned fracture portion 16 is formed using the cutter 35 so as to make a cut without discharging cutting chips and chips after the airbag cover 10 is formed. Yes.

  In the case of the embodiment, as shown in FIGS. 8 and 9, the cutter 35 is an ultrasonic cutter in which the thickness of the main body 36 is 0.5 to 1.0 mm, and includes a single-edged cutting edge 37. The blade 37 is formed to be inclined so as to protrude from the tip 37a toward the base portion 37b toward the moving direction during the cutting process. And in the case of embodiment, the cutter 35 will form the cut | interruption which forms the ditch | groove 16a by arrange | positioning and moving the cutting blade 37 in the moving direction front side.

  Then, the cutting blades that are recessed on the surface side of the cover 10 are stored at both ends of the straight portions 17 and 18 in the planned break portion 16 of the airbag cover 10 and at both ends of the intersecting side portion 19 that becomes the T-shaped intersecting portion 20. A portion 21 is formed. The cutting blade storage portion 21 is formed in advance at the time of molding. As shown in FIGS. 3 to 5, the opening on the back surface side of the cover 10 is rectangular and is recessed in a triangle along the moving direction of the cutter 35. It is arranged as a recess having a cross-sectional shape. 8 and 9, when the cutting blade 37 is inserted to a position where the cut 16a can be formed so as to process the cut of the groove 16a, the cutting blade 37 Is formed in a concave shape that does not make a cut in the inner peripheral surface of the cutting blade storage portion 21. In the case of the embodiment, the cutting blade storage portion 21 is opposed to the surface (cutting blade side facing surface) 23 facing the cutting blade 37 when the cutting blade 37 is inserted and the ridge 36 a side of the cutting blade 37. The inclined surface (the ridge-side facing surface) 24 is inclined so that the length is equal along the moving direction of the cutter 35 and the bottom 22 of the recessed storage portion 21 is an apex. Is formed.

  In this embodiment, the cutting edge side facing surface 23 facing the cutting edge 37 is formed in parallel with the cutting edge 37 when inserted into the cutting edge storage section 21, but the cutting edge storage section 21. The opening angle from the ridge-side facing surface 24 may be inclined as an angle for opening a gap with the cutting edge 37 within a range in which the opening area of the opening is not excessively widened. In the case of the embodiment, the cutting blade storage portion 21 is formed such that the side wall surfaces 25 and 26 are expanded before and after the opposing surfaces 23 and 24 and extend downward (see FIG. 5).

  In the cutting blade storage portions 21 at both ends of each of the linear portions 17 and 18 and the crossing side portion 19, one becomes a start side cutting blade storage portion 21A that starts to cut, and the other has a cut cutter. It becomes the terminal side cutting blade storage part 21B which reaches | attains.

  Further, the thickness of the airbag cover 10 is set such that the thickness T0 of the peripheral portion 31 away from the side wall portion 33 of the ceiling wall portion 11 and the general portion 11a near the center of the door portions 13 and 14 is about 4 mm. The thickness of the planned fracture portion 16 including the portion 21 is set to be in the range of 0.6 to 1.5 mm, and the thickness T1 of the portion around the planned fracture portion 16 is 2 to 3 mm (in the embodiment) 2 mm), the depth D0 of the cutting blade storage portion 21 is 1.0 to 2.0 mm (1.2 mm in the embodiment), and the depth D1 of the groove 16a is 0.8 to 1.0 mm (in the embodiment). 1.0 mm). Therefore, the thickness T2 of the part of the cutting blade storage portion 21 is 0.6 to 0.8 mm (0.8 mm in the embodiment), and the thickness T3 of the part of the concave groove 16a is 0.8 to 1.0 mm (implemented). The shape is 1.0 mm).

  Further, the width W1 on the bottom 22 side between the side wall surfaces 25 and 26 before and after the cutting blade storage portion 21 is 2 to 3 mm (2 mm in the embodiment), and the length L1 of the cutting blade storage portion 21 is also 2 to 3 mm. (3 mm in the embodiment). The dimensions of the width W1 and the length L1 are set in consideration of the dimension in which the cover material 9 to be set by cutting is set with a positional deviation with respect to the set base J, as will be described later. Has been.

  Furthermore, the thickness B of the side wall 33 is set to 2 to 3 mm (2 mm in the embodiment). In addition, in the vicinity of the side wall portion 33 of the ceiling wall portion 11, the thin portion 28 in the vicinity of the linear portions 17, 18 on the door portion 13, 14 side and the outer peripheral side of the side wall portion 33 are located on the side wall portion 33 side. A thin wall portion 29 for gradually reducing the wall thickness, and the thin wall portions 28 and 29 are provided on the side wall portion so that sink marks and gloss unevenness do not occur on the surface side of the ceiling wall portion 11 at the side wall portion 33. It is arranged so as to approximate the wall thickness B of 33.

  Furthermore, a wrinkle pattern 30 is formed in the peripheral areas of the linear portions 17 and 18 and the crossing side portion 19 of the embodiment. In the embodiment, the texture pattern 30 is a fine uneven skin texture pattern of several μm to several tens of μm.

  A description will be given of a cutting process in which a concave groove (cut) 16a for forming the planned fracture portion 16 is formed in the cover material 9 immediately after the airbag cover 10 is molded. A processing apparatus 34 used for this processing is shown in FIG. The cutter 35 is connected to an ultrasonic transmitter (not shown) to hold the cutter 35 so that the cutter 35 can be operated, a laser displacement meter 40 as a measuring instrument for measuring the planned lines 9a and 9b to be processed, and a laser displacement meter. Based on 40 measurement data, it comprises a control device 41 for controlling the drive of the holding arm 39 while operating the ultrasonic transmitter, and a set base 42 for setting the injection-molded cover material 9. Yes. The holding arm 39 is configured to hold the cutter 35 so as to be capable of three-axis movement in the XYZ-axis direction, which is parallel movement along the set table 42 and vertical movement perpendicular to the set table 42. Further, the laser displacement meter 40 is held by the holding arm 39 and measures the depth and arrangement position of the bottom 22 of each cutting blade storage portion 21 as a position reference between the start end and the end of the cut 16a. The height (step) of the peripheral edge of the storage portion 21 and the height along the planned processing lines 9a and 9b are measured. The set table 42 has a shape facing the surface side of the cover material 9 and a suction device (not shown) for adsorbing the set table 42 to the set table 42 side so as not to shift the cover material 9 during processing. The planned line 9a is a line for processing the intersecting side portion 19, and the planned line 9b is a line for processing the linear portions 17 and 18.

  As shown in FIGS. 6 and 7, when the processing device 34 is operated, the cover material 9 after molding is set on the set base 42. First, the cutting edge storage portion of the start end side of the intersecting side portion 19 and the linear portions 17 and 18 is set. The laser displacement meter 40 is moved while measuring the position and step (height) from the bottom 22 of 21A to the bottom 22 of the end-side cutting blade storage 21B through the scheduled processing lines 9a and 9b. . It should be noted that the holding arm 39 that moves at the time of measurement by the laser displacement meter 40 at this time, even if the cover material 9 set on the set base 42 is set in a position-shifted state in advance, The dimension of the length L1 is set in consideration of the positional deviation, and the laser displacement meter 40 is projected from the bottom 22 of the start edge side cutting blade storage part 21A to the machining line 9a. Through 9b, the laser displacement meter 40 is moved so that accurate measurement data can be taken until it reaches the bottom 22 of the end-side cutting blade storage portion 21B.

  Then, after the measurement, the control device 41 that has been input the measurement data from the laser displacement meter 40 moves the holding arm 39 while operating the ultrasonic transmitter to operate the cutting process of the cutter 35. At that time, when the crossing side portion 19 is processed, as shown in FIGS. 8A and 8B, the cutting edge 37 of the cutter 35 is directed to the straight portion 18 side, and the leading end of the straight portion 17 is formed. The cutting edge 37 of the cutter 35 is moved toward the T-shaped intersection 20 on the linear portion 18 side to stop by being inserted into the side cutting blade storage portion 21A to the cutting depth D1 and stopped. Form. If the groove 16a is formed by making a cut (cut) in the entire area of the intersecting side portion 19, the cutting edge 37 of the cut cutter 35 reaches the end side cutting edge storage portion 21B of the T-shaped intersecting portion 20. To do. At that time, the cutting blade storage portion 21B is disposed at a position facing the cutting edge 37 side of the cutter 35 in the direction from the crossing side portion 19 toward the linear portion 18 when the cutting blade 37 side is separated from the crossing side portion 19. It is formed in a shape that allows the cutting edge 37 to be accommodated in a state in which there is no cut with respect to the facing surface 23 of the portion 21B. Therefore, the cutting edge 37 of the cutter 35 does not come into contact with the surface 23 facing the intersecting side portion 19 on the inner peripheral surface of the cutting blade storage portion 21B so as to make a cut, and makes a cut (cut) in the facing surface 23. This can be prevented. Of course, in the embodiment, the cutting edge 37 is not cut also in the ridge-side facing surface 24 in the direction from the intersecting side portion 19 to the linear portion 17 in the starting end side cutting blade storage portion 21A.

  Similarly, in the linear portions 17 and 18, as shown in FIGS. 9A and 9B, the cutting blade 37 of the cutter 35 is inserted into the starting edge side cutting blade storage portion 21A to the cutting depth D1 and stopped. Then, the cutting edge 37 of the cutter 35 is made to reach the end-side cutting edge storage portion 21B to form the concave groove 16a. At this time, in each of the cutting blade storage portions 21A and 21B, the cutting blade 37 of the cutter 35 does not come into contact with the inner peripheral surfaces 23 and 24 of the cutting blade storage portions 21A and 21B so as to make unnecessary cuts.

  And if the fracture | rupture scheduled part 16 which consists of the concave groove 16a is formed, manufacture of the airbag cover 10 will be completed and the airbag cover 10 will be removed from the set stand 42 so that the airbag apparatus S may be assembled. The assembly of the airbag device S is performed by storing and holding the airbag 4 and the inflator 7 that have been stored and folded in advance in the case 6 using the bolts 5a and nuts 6, and the airbag assembly is assembled. Form it. Then, the airbag assembly 10 is covered with the airbag cover 10, the peripheral edges of the locking holes 28 e are locked to the locking claws 8 c, and then the airbag cover 10 is assembled. Is inserted in advance through the opening 2b of the instrument panel 2 mounted on the vehicle, and the locking legs 31a are locked to the opening peripheral edge 2c, and the bracket 8d of the case 6 is fastened to the body 1 side. The airbag device S can be mounted on the vehicle by connecting a lead wire for inputting a predetermined actuation signal extending from the airbag actuation circuit to the inflator 7.

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

  In the airbag cover 10 of the embodiment, as described above, the start and end of the cut 16a are specified in advance as the cutting blade storage portions 21A and 21B from the time of molding, and the arrangement position of the cut 16a. Accuracy can be improved. Further, as the depth D1 of the cut 16a, the cutting blade storage portions 21A and 21B and the peripheral edges thereof are measured in advance by the laser displacement meter 40, and the depth D1 of the cut 16a can be easily adjusted. The cutter 35 can be operated with improved dimensional accuracy of the depth D1.

  Therefore, in the airbag cover 10 of the embodiment, it is possible to manufacture the planned fracture portion 16 while suppressing variations in the position and depth of the cut 16a, and the fracture planned portion 16 can be accurately and smoothly broken even at low temperatures. Can be made.

  Further, in the case of the embodiment, each of the cutting blade storage portions 21 can store the cutting blade 37 of the cutter 35 without making unnecessary cuts, and the deepest bottom portion 22 is disposed deeper than the cut 16a. ing. Therefore, at the time of the cutting process, unnecessary cuts are not formed in the cutting blade storage portion 21, and when the planned breakage portion 16 is broken by being pushed by the airbag 4, the breakage occurs from the cutting blade storage portion 21 to an unplanned part. It can be prevented from progressing.

  Further, in the case of the embodiment, the planned fracture portion 16 includes a T-shaped intersection portion 20 that intersects the one of the linear portions 17 and 18 with the intersection-side portion 19 in a T shape in a plan view. Even if it is made, each cutting blade accommodating part 21 is arrange | positioned at the both ends of the linear site | parts 17 and 18, and is arrange | positioned also at the both ends of the cross | intersection side part 19, and includes the T-shaped intersection part 20. It is arranged. Therefore, even if the crossing side portion 19 of the planned break portion 16 is pushed by the airbag 4 and the breakage proceeds toward the straight portions 17 and 18, the portion is arranged at the T-shaped crossing portion 20. At the position of the cutting blade storage portion 21 formed of a recess having a width that is wider than the cut line 16a, the opposed surfaces 23 and 24 facing each other in the breaking progress direction face each other and stop without exceeding the cutting blade storage portion 21. Can be made. That is, it is possible to prevent unnecessary fragments of the airbag cover 10 from being scattered without unnecessarily extending the breakage.

  And in the manufacturing method of the airbag cover 10 of embodiment, when measuring the line 9a * 9b which will make the cut 16 by the cutter 35 including the position of the start end and the end which put the cut 16a beforehand, the cut 16a Since it is possible to measure the start end and the end of the cutting edge with reference to the bottom 22 of the cutting blade storage portions 21A and 21B recessed from the periphery, the position data of the cut 16a can be easily measured, and the cutting blade storage portion 21 and the peripheral edge thereof can be easily adjusted for the depth D1 of the cut 16a. As a result, the displacement of the cover material 9 due to the thermal expansion depending on the processing temperature and the processing set of the cover material 9 The air bag cover is improved by improving the accuracy of the arrangement position and depth of the cut 16a that forms the planned breaking portion 16 without being affected by the positional displacement at the time. 0 can be produced.

  In the embodiment, the texture pattern 30 is formed in the vicinity of the planned fracture portion 16 including the peripheral edge of the cutting blade storage portion 21, and the laser displacement meter is compared with the case where the texture pattern is not formed. When measuring the planned lines 9a and 9b of the cut line 16a using an optical measuring instrument such as 40 or a camera, it does not reflect like a mirror surface, so the planned lines 9a and 9b can be easily reduced in error. It can be measured. The unevenness of the embossed pattern 30 has a level difference of several to several tens of μm, and the accuracy control of the depth D1 of the cut 16a within an error of ± 0.1 mm can be easily performed.

  In the embodiment, the concave shape of the cutting blade storage portion 21 is an isosceles triangle in cross section along the moving direction of the cutter 35. However, as in the airbag cover 10A shown in FIGS. It is recessed in a right triangle shape along the moving direction of the cutter 35, such as a cutting blade storage 51 having a trapezoidal shape along the moving direction and a flat bottom at the bottom, or an airbag cover 10B shown in FIGS. It is good also as the cutting blade accommodating part 61. FIG. These cutting blade storage portions 51 and 61 also have a rectangular opening on the back side of the cover 10A and 10B, and insert the cutting blade 37 to a position where the cut 16a can be formed to process the cut of the groove 16a. In this case, the cutting edge 37 is formed in a concave shape that does not make a cut in the inner peripheral surface of the cutting edge storage portion 21. That is, each of the cutting blade storage portions 51 and 61 is configured to include the start end / end side cutting blade storage portions 51A, 51B, 61A, and 61B disposed at the positions of the start end and the end of the cut 16a. A surface (cutting blade facing surface) 23 facing the cutting blade 37 when the blade 37 is inserted and a surface (peaking facing surface) 24 facing the peak 36a side of the cutting blade 37 make a cut. Thus, it arrange | positions so that the cutting blade 37 may not be contacted.

  In the embodiment, an example of the H-shaped case in which two T-shaped intersecting portions 20 are arranged as the planned fracture portion 16 is shown, but the planned fracture portion that does not include one linear portion 17. The present invention can also be applied to an airbag cover provided with 16.

  Further, the linear portions 17 and 18 and the intersecting side portions disposed so as to intersect the linear portions 17 and 18 do not have to be linear throughout.

  Furthermore, in the embodiment, the ultrasonic cutter 35 is exemplified as a processing tool having a cutting blade for cutting, but the cut 16a may be formed using a normal cold cutter, a thin rod-shaped end mill, or the like. . However, if a cutter that can cut and form the concave groove 16a without generating chips or chips can be used, the cut 16a that is likely to cause stress concentration at the time of breakage can be formed, and processing of chips and the like is unnecessary. It is preferable. When the groove 16a is formed by cutting with an end mill or the like, the width of the opening is such that an unnecessary cut when the rotating cutting blade such as an end mill is stored in the cutting blade storage portion. It is desirable that the dimension without providing the thickness is about 0.3 to 1.5 mm.

  Further, in the embodiment, the airbag covers 10, 10 A, and 10 B that are separate from the instrument panel 2 used in the passenger seat airbag apparatus S have been described. However, the present invention is applied to an airbag cover that is integrally molded with the instrument panel. In addition, the present invention may be applied to an airbag cover such as an airbag device provided for another driver's seat or on the side of the seat.

It is a perspective view which shows the use condition of the airbag cover of one Embodiment of this invention. It is sectional drawing of the airbag apparatus in which the airbag cover of embodiment is used, and respond | corresponds to the II-II site | part of FIG. It is a partial bottom view of the airbag cover of an embodiment, and shows the neighborhood of a planned breakage part. FIG. 4 is a partially omitted vertical cross-sectional view of the airbag cover of the embodiment, corresponding to the IV-IV part in FIG. 3. FIG. 4 is a partially omitted vertical cross-sectional view of the airbag cover of the first embodiment and corresponds to a VV portion in FIG. 3. It is a figure explaining the measurement state of the planned line which processes the intersection side part of the airbag cover of an embodiment. It is a figure explaining the measurement state of the planned line which processes the linear site | part of the airbag cover of embodiment. It is a figure explaining the state which cuts the intersection side site | part of the airbag cover of embodiment. It is a figure explaining the state which cuts and processes the linear part of the airbag cover of embodiment. It is a fragmentary bottom view of the airbag cover of the modification of an embodiment, and shows the neighborhood of a fracture part. It is a figure explaining the cutting process of the airbag cover shown in FIG. It is a fragmentary bottom view of the airbag cover of the other modification of an embodiment, and shows the neighborhood of a fracture part. It is a figure explaining the cutting process of the airbag cover shown in FIG.

Explanation of symbols

4 ... Airbag,
9 ... cover material,
9a, 9b ... Scheduled line,
10 · 10A · 10B… Airbag cover,
12a ... projecting opening,
16 ... planned to break,
16a ... (cut / cut) concave groove,
18 ... linear part,
19 ... intersection part,
20 ... T-shaped intersection,
21, 51, 61 ... Cutting blade storage,
21A, 51A, 61A ... Start side cutting edge storage,
21B / 51B / 61B ... Terminal blade storage part,
30 ... wrinkle pattern,
35 ... (Processing tool) Cutter,
37 ... Cutting edge.

Claims (3)

Die-molding comprising a thinly-scheduled breakable portion that extends in a linear shape that covers a folded airbag and that can be pushed by the inflating airbag to break and form a projecting opening that projects the airbag Made of synthetic resin formed by
The method of manufacturing an airbag cover, wherein the planned break portion is formed by making a groove-like cut by a cutting blade of a processing tool with respect to the back side of the cover material after molding,
A cutting blade storage portion for storing the cutting blade of the processing tool is formed in advance at the time of mold forming at the position of the start end and the end of the cut in the cover material,
The line to be cut by the processing tool is measured in advance including the positions of the start end and the end of the cut and controlled based on the measured position data, and the processing tool is controlled by the cutting line. The manufacturing method of the airbag cover characterized by forming. The method for manufacturing an airbag cover according to claim 1 , wherein a crease pattern is formed in a vicinity of the portion to be broken including a peripheral edge of the cutting blade storage portion. The method for manufacturing an airbag cover according to claim 1 or 2, wherein the molding for forming the cover material is injection molding.

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