JP4766009B2 - Airbag cover and manufacturing method thereof - 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 and a method for manufacturing the same.

Conventionally, in an air bag cover made of synthetic resin, when the air bag is pushed, a door portion is opened to form a protruding opening, so that a thin breakage planned portion is formed around the door portion. (For example, refer to Patent Document 1). The planned fracture portion was formed by a cutting process that cuts a slit from the back side using a cutting blade of a processing tool such as an ultrasonic cutter.
JP 2005-289254 A

  However, as in the conventional case, in the airbag cover in which the portion to be broken is formed by cutting using the cutting blade of the processing tool, the thickness of the portion to be broken is reduced so that the thickness of the portion to be broken can be strictly formed. There was room for improvement in terms of precision machining.

  The present invention solves the above-described problem, and even when the planned breakage portion of the airbag cover is formed by cutting using a cutting blade of a processing tool, the thickness dimension of the planned breakage portion is accurately determined. It is an object of the present invention to provide a processable airbag cover and a manufacturing method thereof.

An airbag cover according to the present invention covers a folded airbag, and is a thin-walled, thinly-scheduled breakage that can be formed by a linearly extending opening that can be pushed by an inflating airbag to break and project the airbag Part, made of synthetic resin formed by molding,
The planned break portion is an airbag cover configured to include a cutting edge processing portion that is formed by a cutting process for moving a cutting tool from the back side by moving the processing tool after forming and cutting the cutting tool from the back surface side,
A cutting blade storage portion that is recessed on the surface side of the airbag cover is disposed at least at a starting point of the cutting blade processing portion,
The cutting blade storage portion is configured to include an upper determination portion and a lower determination portion formed at two positions shifted in the direction along the depth direction on the side surface side on the cutting blade processing portion side,
The upper determination unit and the lower determination unit are respectively arranged at positions where the thickness and thickness of the cutting blade processing portion are within the allowable range. The cutting edge of the cutting blade at the time of the cutting process is configured to be arranged between the upper determination unit and the lower determination unit.

  In the airbag cover according to the present invention, the planned break portion is configured to include a cutting edge processing portion that is formed by cutting using a cutting blade of a processing tool, and a portion that is at least a starting point of the cutting edge processing portion. The cutting blade storage portion formed in each comprises an upper determination portion and a lower determination portion formed at two positions shifted in the direction along the depth direction on the side surface side on the cutting blade processing portion side. Yes. And this upper side determination part and the lower side determination part are the structures respectively arrange | positioned in the position used as the thin-wall dimension and the thick-wall dimension within the tolerance | permissible_range in a cutting blade process part. Therefore, during the cutting process, if the cutting edge is moved from the state where the cutting edge of the cutting edge is positioned between the upper determination part and the lower determination part, the formed airbag cover is cut. The thickness of the cutting edge processed portion can be made substantially constant within an allowable range, and the thickness dimension of the planned fracture portion can be formed with high processing accuracy.

  Therefore, in the airbag cover of the present invention, even when the planned break portion of the airbag cover is formed by cutting using the cutting blade of the processing tool, the thickness dimension of the planned break portion can be accurately processed. It becomes possible.

Specifically, the airbag cover of the present invention is configured so that, at the time of molding, the cutting blade storage portion that stores the cutting blade is recessed on the surface side at two locations that are the start point and the end point of the cutting blade processing portion, Forming,
The cutting edge processing portion is arranged between the upper determination portion and the lower determination portion disposed on the side of the cutting blade processing portion in the cutting blade storage portion, and the cutting edge of the cutting blade of the processing tool is arranged, After the cutting blade is stored in one cutting blade storage part, the cutting blade is moved to make a cut so that the thickness of the cutting edge processed part is substantially constant from the start point to the end point, and the other cutting blade storage is stored. If it forms by pulling out from a part, it can manufacture.

Further, in the airbag cover of the present invention, specifically, along the direction of travel of the cutting blade, the side surface on the cutting blade processing portion side in the cutting blade storage portion is made shallower toward the cutting blade processing portion side. As a substantially staircase with multiple steps,
It is preferable that the upper determination unit and the lower determination unit are configured by corner portions of adjacent steps.

Furthermore, in the airbag cover of the present invention, the inclined surface is inclined along the traveling direction of the cutting blade so that the side surface on the cutting blade processing portion side in the cutting blade storage portion is shallow toward the cutting blade processing portion side. Configured as
The upper determination unit and the lower determination unit may be formed of linear convex objects or concave objects that are separated from each other on the inclined surface in the traveling direction side of the cutting blade and orthogonal to the traveling direction of the cutting blade. Good.

  As described above, in the case of the cutting blade storage portion provided with the upper determination portion and the lower determination portion, the upper determination portion and the lower determination portion are at positions shifted in the direction along the traveling direction of the cutting blade. Therefore, the thickness of the cutting edge processed portion can be easily confirmed by visually observing the position of the end portion of the cutting edge processed portion from the back side after the airbag cover is manufactured.

  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 in an airbag device S for a passenger seat as shown in FIGS. It is made of a synthetic resin manufactured by injection molding from an olefin-based 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 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 an airbag 4 that is a case 8. A retainer 5 for attaching to the air bag and an air bag cover 10 covering the folded air bag 4 are provided.

  The airbag 4 has a substantially quadrangular pyramid shape with the front end side as a top portion and the rear surface side serving as a 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 window above the upper panel 2a and the instrument panel 2 when the inflation gas flows in. In order to close the space between the shield and the shield, 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.

  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, a substantially rectangular plate-shaped bottom wall portion 8a to which the inflator 7 is inserted from below and attached to the outside of the bottom wall portion 8a. And a plurality of locking claws 8c for locking the side wall 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 case 8 is attached to the case 8 by passing through the bottom wall portion 8a of the case 8 and being fixed to the nut 6.

  As shown in FIGS. 1 to 5, the airbag cover 10 has a substantially rectangular plate-like ceiling wall portion 11 disposed so as to close the opening 2 b of the instrument panel 2, and a lower side from the lower surface (back surface) side of the ceiling wall portion 11. And a side wall portion 39 having a substantially rectangular tube shape extending in the direction. The front wall 39a and the rear wall 39b in the side wall 39 are formed with a plurality of locking holes 39e for locking the peripheral edges of the locking claws 8c of the peripheral wall 8b in the case 8. The side wall 39 is a part that covers the periphery of the folded airbag 4 together with the peripheral wall 8 b of the case 8.

  The ceiling wall portion 11 is configured to include a protruding opening portion 12 disposed at a portion surrounded by the side wall portion 39 and a peripheral edge portion 37 around the opening portion 12. The peripheral edge 37 has a plurality of locking legs 37a formed on the peripheral edge 2c of the opening 2b so as to eliminate rattling when the airbag cover 10 is disposed so as to close the opening 2b of the instrument panel 2. It protrudes downward (see FIG. 2).

  As shown in FIGS. 2 to 5, the protruding opening 12 is a rectangular plate, and as shown in FIGS. 2 to 5, two doors 13 and 14 that are opened on both the front and rear sides when opened, and a fracture disposed around the doors 13 and 14. And a scheduled portion 16. The fracture | rupture scheduled part 16 is made into a substantially H shape seeing from upper direction, and the vertical bar parts 17 and 18 arrange | positioned along the front-back direction in the both right and left sides of the door parts 13 and 14, and the door part 13, 14 and a horizontal bar portion 19 disposed substantially along the left-right direction. When the planned break portion 16 is broken, the two front and rear door portions 13 and 14 are opened on both front and rear sides to form a rectangular opening 12a for protruding the airbag 4. 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 part 15 is arrange | positioned in the position of the inner surface of the front wall part 39a in the side wall part 39, and the rear wall part 39b as a site | part which connects the both ends which oppose the vertical bar parts 17 and 18 in the left-right direction.

  In the case of the embodiment, as shown in FIGS. 2 to 5, the planned fracture portion 16 is formed by providing two types of concave grooves 16 a and 16 b that are recessed from the rear surface side to the front surface side of the airbag cover 10. Specifically, the two vertical bar portions 17 and 18 are configured to be provided with a concave groove 16b formed by molding at the time of injection molding of the airbag cover 10, and the horizontal bar portion 19 is formed of the airbag cover 10. After the molding, a concave groove 16a formed by using a cutter 41 as a processing tool is provided. That is, in the case of the embodiment, the horizontal bar portion 19 in the planned fracture portion 16 is the cutting edge processing portion 20 formed by the cutting processing for cutting a slit from the back surface side by the cutting blade 43 of the cutter 41. Then, the cutting blades that are recessed on the front surface side of the airbag cover 10 are provided at the left and right ends of the horizontal bar portion 19 that is the intersection 21 of the horizontal bar portion 19 (cutting blade processing portion 20) and the vertical bar portions 17 and 18. A portion 23 is provided. Each cutting blade storage unit 23 constitutes a starting point BP and an end point LP of the cutting blade processing unit 20.

  In the case of the embodiment, the cutter 41 as a processing tool includes a single-edged cutting blade 43 as an ultrasonic cutter in which the thickness of the main body 42 is 0.5 to 1.0 mm, as shown in FIGS. It is configured. The cutting blade 43 is formed to be inclined so as to protrude from the tip 43a serving as the cutting edge toward the base portion 43b toward the moving direction during cutting (the traveling direction RD of the cutting blade 43). And in the case of embodiment, the cutter 41 will form the cut | interruption which forms the ditch | groove 16a by arrange | positioning and moving the cutting blade 43 in the front side of the advancing direction RD.

  The cutting blade storage portion 23 formed at the intersecting portions 21 and 21 of the vertical bar portions 17 and 18 and the horizontal bar portion 19 is formed in advance at the time of molding. The size is set such that the cutting blade 43 can be accommodated (see FIGS. 3 to 6). In the case of the embodiment, specifically, the cutting blade storage portion 23B formed on the start point BP side and the cutting blade storage portion 23L formed on the end point LP side are side surfaces on the side away from the horizontal bar portion 19. It is comprised so that the shape of may differ. In the cutting edge storage portion 23B on the start point BP side, the side surface 24 on the side away from the horizontal bar portion 19 is configured as a flat surface along the depth direction DD of the concave portion 16a constituting the horizontal bar portion 19, and the end LP side In the cutting blade storage portion 23L, the side surface 25 on the side away from the horizontal bar portion 19 is an inclined surface that substantially follows the inclination of the cutting blade 43 in the cutter 41, and the cutting blade 43 of the cutter 41 that moves while being cut is processed. However, when the cutting edge processed portion 20 (horizontal bar portion 19) is formed and separated from the cutting edge processed portion 20, a cut is made with respect to the side surface 25 (the surface on the front side in the traveling direction RD of the cutter 41). It has a shape that does not exist. In each of the cutting blade storage portions 23B and 23L, the portions other than the side surfaces 24 and 25 have the same shape and are given the same reference numerals.

  As shown in FIGS. 4 and 5, the bottom surface 26 of each of the cutting blade storage portions 23 </ b> B and 23 </ b> L is a flat surface parallel to the traveling direction RD of the cutter 41. The front side surface 27 and the rear side surface 28 extending from the side are formed so as to expand and extend downward (see FIG. 5). Further, the processing side surface 29 on the side of the horizontal bar portion 19 (cutting blade processing portion 20) in each of the cutting blade storage portions 23B and 23L is formed so that the dent is shallow from the bottom surface 26 to the cutting blade processing portion 20 side. It is made into the substantially step shape which provided the several level | step difference along the advancing direction RD. In the case of the embodiment, each processed side surface 29 is provided with three steps 30 whose height dimension (depth dimension) is substantially equal on the bottom surface 26 side, and a portion that is on the surface side from the step 30 is subjected to cutting edge processing. It is made into the inclined surface shape which makes a dent shallow toward the part 20 side. In addition, on each processing side surface 29, an upper determination unit 31 and a lower determination unit 32 that determine the position of the tip 43a of the cutting blade 43 at the time of cutting are provided at two positions that are shifted in the direction along the depth direction DD. Is formed.

  The upper side determination unit 31 and the lower side determination unit 32 are, at a position where the thickness of the cutting edge processing unit 20 formed at the time of cutting is set to a thin dimension within an allowable range, and a position where the thickness is set to a thick dimension, Each is arranged. In the case of the embodiment, as shown in FIGS. 6 and 8, the corner portion 30ua of the step 30U located on the bottom surface 26 side (upper surface side when mounted on a vehicle) is the upper determination unit 31 and is arranged adjacent to the step 30U. The corner 30da of the step 30D to be made is the lower determination unit 32. The upper determination part 31 is a boundary part where the thickness of the cutting edge processing part 20 becomes thin, and is formed when the tip 43a of the cutting edge 43 is located on the bottom surface 26 side (upper surface side) from the upper determination part 31. The thickness of the cutting edge processed portion 20 is a thin wall outside the allowable range. The lower determination unit 32 is a boundary portion where the thickness of the cutting blade processing unit 20 is thick, and the cutting blade formed when the tip 43a of the cutting blade 43 is positioned on the lower surface side of the lower determination unit 32. The thickness of the processed portion 20 is outside the allowable range. In the case of the embodiment, the upper determination unit 31 and the lower determination unit 32 are configured by corner portions 30ua and 30da of stepped steps 30U and 30D arranged adjacent to each other. The lower determination unit 32 is not only disposed at a position shifted in the direction along the depth direction DD, but also disposed at a position shifted in the direction along the traveling direction RD (left-right direction) of the cutter 41. Has been. During the cutting process, the cutter 41 positions the cutting edge (tip) 43a of the cutting blade 43 stored in the cutting blade storage portion 23B between the upper determination portion 31 and the lower determination portion 32. Then, the cutting edge 43 is advanced along the traveling direction RD, and a cut is made in the portion of the cutting edge processing portion 20 to form the cutting edge processing portion 20 (concave groove 16a).

  In the case of the embodiment, as shown in FIGS. 3 to 5, the meat of the general part 11 a near the center of the peripheral part 37 and the door parts 13, 14 apart from the side wall part 39 in the ceiling wall part 11 of the airbag cover 10. The thickness T0 is set to about 5.0 mm. The thickness T1 of the site around the planned fracture portion 16 is set to 3.0 to 5.0 mm (3.8 mm in the case of the embodiment), and the depth D0 of the cutting blade storage portions 23B and 23L is 0.5. It is set to ˜3.0 mm (2.5 mm in the case of the embodiment). In the embodiment, the thickness T0 of the general portion 11a is set to be larger than the thickness T1 of the portion around the planned fracture portion 16, but of course the thicknesses T1 and T2 so that T0 ≦ T1. May be set. Further, the depth D1 of the groove 16a is set to 0.5 to 3.5 mm (2.0 mm in the embodiment), and the depth D2 of the groove 16b is 0.5 to 3.5 mm (in the case of the embodiment). 2.8 mm). The thickness T2 of the cutting blade storage portions 23B and 23L is set to 0.5 to 2.5 mm (1.3 mm in the embodiment). The thickness T4 of the concave groove 16b is set to 0.5 to 2.5 mm (1.0 mm in the embodiment). Further, the width W1 of the concave groove 16b is set to 3 to 15 mm (5 mm in the embodiment).

  In the embodiment, the separation distance along the depth direction DD between the upper determination section 31 and the lower determination section 32 (distance along the depth direction DD between the corner portions 30ua and 30da) DL1 (see FIG. 6) Is set to 0.2 mm. In the embodiment, the cutter 41 is configured such that the cutting edge (tip) 43a of the cutting blade 43 stored in the cutting blade storage portion 23B is positioned between the upper determination unit 31 and the lower determination unit 32. Then, a cut is made in the portion of the cutting edge processed portion 20 to form the cutting edge processed portion 20 (concave groove 16a). Specifically, in the case of the embodiment, the thickness T3 of the cutting edge processed portion 20 is set within a range of 1.7 to 1.9 mm. Further, the depth D1 of the concave groove 16a is set to 1.9 to 2.1 mm (see FIG. 4).

  Next, the manufacturing method of the airbag cover 10 of embodiment is described. First, using a predetermined injection molding die, the cover material 9 in which the concave grooves 16b of the vertical bar portions 17 and 18 are formed and the concave grooves 16a are not formed is molded. And this cover raw material 9 is taken out from a shaping | molding die, and as shown to FIGS. 6-8, it arrange | positions to the set stand J of the cutter apparatus C in which the cutter 41 was arrange | positioned. The set table J is provided with a suction device (not shown) that sucks the cover material 9 at the side of the set table J so as not to shift the cover material 9 during processing. Further, as shown in FIG. 7, the cutter apparatus C holds the cutter 41 so that the cutter 41 can be moved in parallel along the set base J and can be moved in three directions in the X, Y, and Z directions in the vertical direction perpendicular to the set base J. And a control circuit 49 for controlling the operation of the holding mechanism 48. Further, the cutter device C includes cameras 51B and 51L configured by a CCD camera or the like that detects the position of the tip (blade edge) 43a of the cutting blade 43 in the cutter 41 at the start point BP and the end point LP, and the control circuit 49 includes a camera. And a lamp 52 that blinks when an abnormal position of the tip 43a of the cutting edge 43 is detected by 51B and 51L (see FIG. 7). Note that, in the case of the embodiment, the cutter 41 moves with a constant trajectory with respect to the set table J so that the distance of the tip 43a of the cutting edge 43 from the set table J is constant during the cutting process. Specifically, the control circuit 49 is configured so that the airbag cover 10 appropriately set on the set base J can move horizontally from the start point BP to the end point LP to make a break. Thus, teaching is performed in advance.

  In the embodiment, first, the cutting blade 43 of the cutter 41 is directed toward the traveling direction side with respect to the cover material 9 that is substantially uniformly adsorbed to the set table J using a suction device (not shown). The state is stored in the cutting blade storage part 23B on the start point BP side. At this time, the cutting blade 43 is inserted and stopped to the cutting depth D1 so that the tip (cutting edge) 43a is disposed between the upper determination unit 31 and the lower determination unit 32 in the depth direction DD. (See A in FIG. 8). Next, as shown in FIGS. 7B and 7C, the cutting edge 43 of the cutter 41 is moved to the vertical bar 18 side so that the depth position of the tip (cutting edge) 43a is substantially constant from the start point BP to the end point LP. The cutting edge processed portion 20 is formed by moving the cutting edge. If the groove 16a is formed by making a cut (cut) in the entire area of the cutting edge processing portion 20, the cutting edge 43 of the cutter 41 after the cutting is cut on the end LP side as shown in FIG. 8C. It reaches the blade storage portion 23L. Then, if the cutting blade 43 of the cutter 41 is removed from the cutting blade storage portion 23L, the cutting blade processing portion 20 (concave groove 16a) can be formed. During the cutting process, the control circuit 49 causes the tip 43a of the cutting blade 43 to be below the lower determination unit 32 (upper during processing) or above the upper determination unit 31 (lower during processing) by the cameras 51B and 51L. When the position is detected, the lamp 52 blinks, and the operator is made to detect the abnormality. Such a defect is often caused by a positional shift when the cover material 9 is set on the setting table J.

  In the airbag cover 10 of the embodiment, in the cutting blade storage portion 23L on the end point LP side, the side surface 25 on the side away from the cutting blade processing portion 20 (horizontal bar portion 19) is inclined of the cutting blade 43 in the cutter 41. When the cutting edge 43 of the cutter 41 that moves while being cut is formed as a slanted surface substantially along the horizontal axis portion 19 and is separated from the cutting edge processed portion 20, the side surface 25 (cutter traveling direction) It is configured in a shape so as not to make a cut with respect to the front side surface. Therefore, it is possible to prevent the cutting edge 43 of the cutter 41 from coming into contact with the side surface 25 of the cutting blade storage portion 23 </ b> L so as to make a cut and making a cut into the side surface 25.

  And if the cutting edge process part 20 is formed, manufacture of the airbag cover 10 will be completed and the airbag cover 10 will be removed from the set stand J 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 8 using the bolts 5a and nuts 6, and assembled with the airbag assembly. Is formed. The airbag assembly 10 is covered with the airbag cover 10, and the engagement claw 8 c of the case 8 is engaged with the peripheral edge of the engagement hole 39 e provided in the side wall portion 39 of the airbag cover 10. Stop. Thereafter, the airbag assembly with the airbag cover 10 already assembled is inserted in advance from the opening 2b of the instrument panel 2 mounted on the vehicle, and each locking leg 37a is locked to the peripheral edge 2c of the opening 2b. The bracket 8d of the case 8 is fastened to the body 1 side. Then, if a lead wire (not shown) for inputting a predetermined actuation signal extending from the airbag actuation circuit is connected to the inflator 7, the airbag device S can be mounted on the vehicle.

  When the airbag device S is activated, 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. The breakable portion 16 is broken and the door portions 13 and 14 of the airbag cover 10 are opened on both the front and rear sides, and the opening 12a formed by opening is greatly protruded so as to protect the passenger seated on the passenger seat. Will be.

  In the airbag cover 10 of the embodiment, the planned break portion 16 includes the cutting edge processing portion 20 formed by cutting using the cutting edge 43 of the cutter 41 as a processing tool. The cutting blade storage portion 23B formed at the site serving as the starting point BP of the blade processing portion 20 is formed at two positions shifted in the direction along the depth direction DD on the processing side surface 29 side serving as the cutting blade processing portion 20 side. The upper determination unit 31 and the lower determination unit 32 are provided. The upper side determination unit 31 and the lower side determination unit 32 are disposed at positions where the thickness and thickness of the cutting edge processing unit 20 are within the allowable range. Therefore, as shown in FIG. 8, the tip (blade edge) 43a of the cutting blade 43 is interposed between the upper determination portion 31 and the lower determination portion 32 in the cutting blade storage portion 23B on the start point BP side during the cutting process. If the cutting edge 43 is moved along the traveling direction RD from the state where the position is positioned, and the cover material 9 of the molded airbag cover is cut, the groove 16a in the planned fracture portion 16 has a depth. D1 can be formed substantially constant. That is, the cutting edge processed portion 20 can be formed with the wall thickness being substantially constant within an allowable range.

  Therefore, in the airbag cover 10 of the embodiment, even when the planned fracture portion 16 of the airbag cover 10 is formed by cutting using the cutting blade 43 of the cutter 41, the thickness dimension of the planned fracture portion 16 is accurate. It can be processed well.

  Further, in the airbag cover 10 of the embodiment, the cutting blade 43 advances so that the processing side surface 29 on the cutting blade processing portion 20 side in the cutting blade storage portions 23B and 23L is shallow toward the cutting blade processing portion 20 side. As a substantially stepped shape having a plurality of steps 30U and 30D along the direction RD, the upper determination unit 31 and the lower determination unit 32 are configured by the corners 30da and 30ua of the adjacent steps 30U and 30D. . That is, in the airbag cover 10 of the embodiment, the upper determination unit 31 and the lower determination unit 32 are not only in the direction along the depth direction DD but also in the direction along the traveling direction RD (left-right direction) of the cutter 41. Also in FIG. Therefore, even if it does not detect with the cameras 51B and 51L, after manufacturing the airbag cover 10, the operator himself / herself looks at the position of the edge part of the cutting blade processing part 20 from the back surface side, so that the meat of the cutting blade processing part 20 is obtained. The thickness can be easily confirmed. Specifically, in the airbag cover 10 of the embodiment, when viewed from the back side, if the cutting edge processing portion 20 is formed from the corner portion 30da to the entire step 30D, the cutting edge processing portion 20 is It is formed to an appropriate thickness within the allowable range (see FIG. 3). Of course, if such points are not taken into account, a processing side surface on which the upper determination unit and the lower determination unit are arranged is formed along the depth direction, and the upper determination unit and the lower determination unit are formed in the depth direction. It may be arranged so as to be shifted only along.

  Further, as the airbag cover, as in the airbag cover 10A shown in FIGS. 9 and 10, the processing side surface 29A on the cutting edge processing portion 20A side of the cutting blade storage portions 23BA and 23LA is directed toward the cutting edge processing portion 20A to make the dent shallow. As described above, the cutting blade 43 is configured as an inclined surface that is inclined along the traveling direction RD, and the upper determination portion 31A and the lower determination portion 32A are formed on the inclined surface (working side surface) 29A. It is also possible to use a plurality of protrusions 46U and 46D that are separated from each other in the traveling direction RD side and project from the linear processing side surface 29A orthogonal to the traveling direction RD of the cutting edge 43. As shown in FIGS. 9 and 10, these protrusions 46U and 46D are formed at positions on the processed side surface 29A on the bottom surface 26A side. Also in the airbag cover 10A, the upper determination part 31A is a boundary part where the thickness of the cutting edge processing part 20A is thin, and the lower determination part 32A is that the thickness of the cutting edge processing part 20A is thick. This is the boundary part. The separation distance DL2 between the upper determination unit 31A and the lower determination unit 32B along the depth direction DD is set to 0.2 mm.

  Also in such an airbag cover 10A, the cutting edge storage portion 23BA formed at the site that is the starting point BP of the cutting edge processing portion 20A is in the depth direction DD on the processing side surface 29A side that is the cutting edge processing portion 20A side. The upper determination unit 31A and the lower determination unit 32A are formed at two positions shifted in the direction along the upper and lower determination units 32A. The upper determination unit 31 and the lower determination unit 32 are allowable in the cutting edge processing unit 20. They are arranged at positions where the thickness and thickness of the wall within the range are obtained. Therefore, during the cutting process, the cutting blade 43 is moved along the traveling direction RD from the state in which the tip (blade edge) 43a of the cutting blade 43 is positioned between the upper determination unit 31A and the lower determination unit 32A. Then, if the cover material 9A of the molded airbag cover is cut, the cutting edge processed portion 20A in the planned fracture portion 16A can be formed within an allowable range with a substantially constant thickness (FIG. 10). Also in the airbag cover 10A having the above-described configuration, the upper determination unit 31A and the lower determination unit 32A are disposed at positions shifted in the direction along the traveling direction RD (left-right direction) of the cutter 41. Therefore, even if it is not detected by the camera, the thickness of the cutting edge processing portion 20A can be determined by visually checking the position of the end portion of the cutting edge processing portion 20A from the back side after manufacturing the airbag cover 10A. Can be easily confirmed. Specifically, in the airbag cover 10A having the above-described configuration, when the end portion of the cutting edge processing portion 20A is disposed between the projecting portions 46U and 46D when viewed from the back surface side, the cutting edge processing portion 20A. Is formed to an appropriate thickness within an allowable range (see the parentheses in FIG. 9).

  In the case of the embodiment, the inclination angles θ1 and θ2 (see FIGS. 6 and 9) with respect to the horizontal direction of the processed side surfaces 29 and 29A (the traveling direction RD of the cutting edge 43) are 30 to 60 ° (desirably 40 to 50 °). It is preferable to set. If the inclination angle is less than 30 °, when the airbag cover 10 and 10A after manufacture is viewed from the back side, it is difficult to visually check the positions of the end portions of the formed cutting blade processed portions 20 and 20A. This is because if the inclination angle exceeds 60 °, the thin-walled region becomes wider and the appearance may be deteriorated. In the case of the embodiment, specifically, the inclination angles θ1 and θ2 are set to 45 °.

  9 and 10, the upper determination unit 31A and the lower determination unit 32A are formed with a plurality of linear protrusions 46U and 46D protruding from the inclined surface (processed side surface) 29A. The lower determination unit is not limited to this, and the upper determination unit and the lower determination unit may be configured from a plurality of linear grooves formed to be recessed from the inclined surface.

  In the embodiment, the cutter device C is configured such that the tip 43a of the cutting edge 43 in the cutter 41 draws a constant locus, and the control circuit 49 causes the upper determination unit 31 and the lower determination unit 32 by the cameras 51B and 51L. The position of the tip 43a of the cutting edge 43 of the cutter 41 is detected inside, but the cutter device is not limited to this. For example, as a cutter device, the control circuit can detect the position of the upper determination unit and the lower determination unit in the vicinity of the start point and the end point of the cover material adsorbed to the set table by the camera, and the tip of the cutting blade Use a configuration that moves the cutter and removes the cutting blade from the cutting edge storage part on the end point side so that it is positioned between the upper determination part and the lower determination part in the cutting edge storage part on the starting point side May be. If the cutter device having such a configuration is used, even if the cover material is set in a state of being displaced with respect to the set base, the error due to the displacement can be absorbed. It can be formed properly.

  Further, in the embodiment, the straight horizontal bar portion 19 arranged along the left-right direction, which is a part of the substantially H-shaped fracture planned portion 16, is constituted by the cutting edge processed portion 20. The shape of the planned portion is not limited to this, and if the blade tip storage portion is arranged on the start point side and the end point side, the entire break planned portion is cut from the back side by the cutting edge of the processing tool. You may form by the cutting process to insert.

  Furthermore, in the embodiment, the ultrasonic cutter 41 is exemplified as a processing tool having a cutting blade for performing a cutting process. However, the cutting blade processing unit 20 is formed by using a normal cold cutter, a thin rod-shaped end mill, or the like. It may be formed. However, if a cutter that can cut and form the concave groove 16a without generating chips or chips can be used, the cutting edge processed portion 20 that is likely to cause stress concentration at the time of breakage can be formed, and chips and the like can be formed. Processing is also unnecessary, which is preferable.

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

It is a perspective view which shows the use condition of the airbag cover which is 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 embodiment and corresponds to a VV portion in FIG. 3. In the airbag cover of an embodiment, it is a partial expanded sectional view showing the part of a cutting blade storage part. It is the schematic which shows the cutter apparatus which cuts into the airbag cover of embodiment. It is a figure explaining the cutting process of the airbag cover of embodiment. In the airbag cover of a modification, it is a partial expanded sectional view and a partial expanded bottom view showing a part of a cutting blade storage part. It is a figure explaining the cutting process of the airbag cover of a modification.

Explanation of symbols

4 ... Airbag,
10, 10A ... airbag cover,
12a ... projecting opening,
16 ... planned to break,
16a ... concave groove,
20, 20A ... cutting edge processing part,
23B, 23L, 23BA, 23LA ... cutting blade storage part,
29, 29A ... processing side surface,
30U, 30D ... steps,
30ua, 30da ... edge,
31, 31A ... Upper determination unit,
32, 32A ... lower determination unit,
41 ... Cutter (processing tool),
43 ... Cutting blade,
43a ... tip (blade edge),
46U, 46D ... Convex part.

Claims (4)

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 air bag cover having a configuration in which the portion to be broken includes a cutting edge processing portion that is formed by moving a processing tool and forming a cut from the back side with the cutting edge of the processing tool after molding. ,
A cutting blade storage portion that is recessed on the front surface side of the airbag cover is disposed at least at a starting point of the cutting blade processing portion,
The cutting blade storage portion is configured to include an upper determination portion and a lower determination portion formed at two positions shifted in the direction along the depth direction on the side surface side on the cutting blade processing portion side,
The upper determination unit and the lower determination unit are respectively disposed at positions where the thickness and thickness of the cutting edge processing unit are within the allowable range, and An airbag cover configured so that a cutting edge of the cutting blade at the time of cutting of the blade processing portion can be disposed between the upper determination portion and the lower determination portion. The side surface of the cutting blade storage portion on the side of the cutting blade processing portion has a substantially stepped shape with a plurality of steps along the traveling direction of the cutting blade so that the dent is shallow toward the cutting blade processing portion side. And
The airbag cover according to claim 1, wherein the upper determination unit and the lower determination unit are configured by corner portions of the adjacent steps. The side surface on the cutting edge processing portion side in the cutting blade storage portion is configured as an inclined surface that is inclined along the traveling direction of the cutting blade so as to make the dent shallow toward the cutting edge processing portion side,
On the inclined surface, the upper determination unit and the lower determination unit are separated from each other on the traveling direction side of the cutting blade, and from a linear protrusion or a concave groove that is orthogonal to the traveling direction of the cutting blade, The airbag cover according to claim 1, wherein the airbag cover is configured. 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 having a configuration in which the portion to be broken includes a portion formed by a cutting process of moving a cutting tool from the back surface side by moving a processing tool after forming and cutting a cutting edge of the processing tool. ,
A cutting blade storage portion for storing the cutting blade when forming a cutting edge processing portion formed by cutting at the portion to be broken in the airbag cover is a starting point and an end point of the cutting blade processing portion 2 In place, it is formed so as to be recessed on the surface side,
Each of the cutting blade storage portions is formed at two positions shifted in the direction along the depth direction on the side surface side of the cutting blade processing portion, and has a thin thickness within an allowable range in the cutting blade processing portion. It is configured to include an upper determination unit and a lower determination unit that are disposed at the position where the dimension and the thick dimension are provided,
The cutting edge processing section stores the cutting edge in one of the cutting edge storage sections such that the cutting edge of the cutting edge of the processing tool is disposed between the upper determination section and the lower determination section. After that, the cutting blade is moved and cut so that the thickness of the cutting edge processed portion is substantially constant from the start point to the end point, and then formed by removing from the other cutting blade storage portion. A method for manufacturing an airbag cover, characterized in that:

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