JP2007161062A - Airbag door and its forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve smooth rupture of a rupture schedule line without spoiling an outer appearance of a base material by forming a groove. <P>SOLUTION: An airbag door AD constituted of two pieces of door panels 16, 16 provided on the base material 12 constituting an instrument panel has the central groove 34 making the central rupture schedule line 32 on a boundary line on both of the door panels 16, 16. This central groove 34 is constituted of a first groove part 38 set in required first groove width W1 and making the open end side of the central groove 34 and a second groove part 40 set in second groove width W2 narrower than the first groove part 38 and making the bottom part side of the central groove 34. Additionally, step parts 36, 36 formed on a boundary portion of the first groove part 38 and the second groove part 40 are formed so as to project inward from a line connecting a surface part 33 of the base material 12 corresponding to a center in the cross direction of the central groove 34 on the central rupture schedule line 32 and open ends 34a, 34a of the central groove 34 to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an airbag door having a groove that forms a center fracture planned line in a boundary line between two door panels provided on a base material constituting an interior member for a vehicle, and a method for forming the airbag door.

  A vehicle such as a passenger car is equipped with an airbag device for protecting passengers. Among these, an airbag device for a passenger seat is, for example, a vehicle interior assembled in front of a passenger compartment as shown in FIG. It is equipped in a state where it is stored inside the instrument panel 10 as a member. For this reason, the base panel 12 constituting the instrument panel 10 is integrally formed with door panels 16 and 16 of an airbag door 14 that is opened and displaced toward the passenger compartment at a portion corresponding to an airbag device (not shown). Yes. These door panels 16 and 16 always constitute the design surface as a part of the base material 12, and when the airbag device is actuated to receive the pressing force of the inflating airbag 50, the base material 12 When the door 12 is broken at a door breaking planned line 20 formed in advance and formed at the time of molding 12, it is separated from the base material 12 and is allowed to open (see FIG. 8 or FIG. 9). ). It is important that the door panels 16 and 16 do not prevent smooth deployment of the airbag, which takes about 1/100 second from the start of inflation to the completion of inflation.

Here, in the case of the double-opening type air bag door 14, the planned door break line 20 provided on the outer edge of each door panel 16, 16 is at least the central break planned line 22 provided along the boundary line in both door panels 16, 16. And side end fracture lines 24 and 24 provided along the side edge edges 16b and 16b facing each other of the door panels 16 and 16, respectively (see FIG. 8A). Further, in the airbag door 14 in which the door panels 16 and 16 are completely separated from the base material 12 and opened, the door doors 16 and 16 are connected to the end portions of the both-side end planned break lines 24 and 24 and Parallel base end fracture lines 26 are additionally formed. Both door panels 16 and 16 are supported on the back side by a backup member 28 connected to the airbag device, and when the airbag device is operated, the rear door panel 16 opens to the passenger seat side and the front door panel. 16 opens to the front glass side. In addition, the technique regarding such an airbag door is disclosed by patent document 1, for example.
JP 2001-315605 A

  By the way, when the airbag device is activated and the airbag 50 starts to be inflated and the door panels 16 and 16 are pushed upward, the central fracture planned line 22 of the planned door fracture line 20 and other planned fracture lines 24, 26 is broken, and the door panels 16 and 16 are opened and displaced about the hinge portion 28a of the backup member 28 supporting the base end edges 16c and 16c of the door panels 16 and 16, respectively. At this time, in the initial stage before the central fracture line 22 breaks, the front edges (open ends of the grooves) 16a and 16a of the door panels 16 and 16 facing each other with the groove 18 constituting the central fracture line 22 interposed therebetween. However, they may come into contact with the door panels 16 and 16 being pushed up (see FIG. 9B). When the leading edges 16a and 16a come into contact with each other in this way, the center fracture planned line 22 is prevented from being broken, and there is a disadvantage that a large amount of energy is required for the opening displacement of the door panels 16 and 16.

  Therefore, it is conceivable to form the groove 18 constituting the center fracture planned line 22 with such a width that the front end edges 16a and 16a facing each other when the door panels 16 and 16 are opened are not interfered with each other. However, both door panels 16 and 16 are required to be appropriately configured as a part of the base material 12 before the operation of the airbag device (see FIG. 9A), and the width of the groove 18 is set wide. This is disadvantageous in that the instrument panel 10 is likely to be deformed due to a heat history at the time of groove formation, insufficient strength, or the like.

  In the case of forming the groove 18 described above, (1) in the molding process of the base material 12, the groove 18 is formed simultaneously with the molding of the base material 12 by the projecting piece projecting forward and backward into the cavity defined in the molding die. And (2) a laser processing method, etc. are employed. Among these methods, the method (1) has an adverse effect such as fluctuations in the curing rate due to the flow of the resin material in the cavity being hindered by the enlarged protrusion, and the pattern is formed on the surface side of the molded substrate 12. There was a problem that caused the appearance to deteriorate, such as being raised. In the method (2), since the grooves 18 are formed by laser processing, it is difficult to form the grooves 18 having a relatively wide width due to restrictions on processing equipment.

  That is, the present invention has been proposed in order to suitably solve these problems inherent in the airbag door according to the prior art, and without breaking the appearance of the base material due to the formation of grooves, It is an object of the present invention to provide an airbag door that realizes a smooth break of a planned line.

In order to overcome the above-mentioned problems and achieve the intended purpose, an airbag door according to claim 1 of the present application is
In an airbag door having a groove that forms a planned center fracture line in a boundary line of two door panels provided on a base material that constitutes a vehicle interior member,
The groove is configured such that the width of the bottom portion is set narrower than the separation width of the open end, and the surface of the base material corresponding to the center in the width direction of the groove on the center fracture planned line is located in the middle of the side wall surface. And a step portion protruding inward from a line connecting the portion and the open end of the groove.
According to the first aspect of the present invention, since the groove constituting the central fracture line is set to have a width at the bottom that is narrower than the separation width of the open end, adverse effects on the appearance due to the formation of the groove are avoided. obtain. Further, since the step portion is provided opposite to the side wall surface of the groove, the door portions formed by the side wall surface of the groove do not contact the open ends of the groove when the door panels are opened and displaced. By appropriately controlling the interference between the leading edges of the two, it is possible to smoothly break the central fracture line.

According to a second aspect of the present invention, in the airbag door according to the first aspect, the groove is set to a required width, and has a first groove portion that forms an open end side of the groove, and a narrower width than the first groove portion. And the step portion formed at the boundary portion between the first groove portion and the second groove portion is from the middle of the base material in the thickness direction. It is provided in a portion biased toward the bottom side of the groove.
According to the invention which concerns on Claim 2, by providing the step part in the site | part biased to the bottom part side of the groove | channel from the intermediate | middle of the thickness direction in a base material, in the case of the open displacement of both door panels, between the front-end edges of a door panel further By appropriately controlling the interference, the central fracture line can be smoothly broken.

In order to overcome the above-mentioned problems and achieve the intended object, a method for forming an airbag door according to claim 3 of the present application is as follows.
A method for forming an airbag door having a groove forming a central fracture line in a boundary line of two door panels provided on a base material constituting a vehicle interior member,
A rotary cutting tool is cut from one surface of the base material to a depth of half or more of the thickness of the base material, and the rotary cutting tool is moved along the boundary line to form a first groove portion having a required width. ,
A rotary cutting tool is cut to a required depth from the bottom surface of the first groove portion, and the rotary cutting tool is moved along the extending line of the first groove portion, whereby the second groove portion having a narrower width than the first groove portion. Form the
On the side wall surface of the groove, which is a boundary portion between the first groove portion and the second groove portion, a surface portion of the base material corresponding to the center in the width direction of the groove on the center fracture planned line and an open end of the groove A step portion protruding inward from the connected line is provided.
According to the invention of claim 3, when forming the groove, it is possible to avoid an adverse effect on the appearance,
When opening both door panels, the stepped portions are brought into contact with each other, thereby appropriately controlling the interference between the edge edges of the door panel formed by the side wall surfaces of the grooves, so that the groove that can smoothly break the central fracture line can be easily obtained. Can be formed.

In order to overcome the above-mentioned problems and achieve an intended purpose, an air bag door forming method according to claim 4 of the present application includes:
A method for forming an airbag door having a groove forming a central fracture line in a boundary line of two door panels provided on a base material constituting a vehicle interior member,
By cutting a rotary cutting tool from one surface of the base material to the depth of the groove, and moving the rotary cutting tool along the boundary line, a second groove portion having a narrow width is formed,
A rotary cutting tool is cut from one surface of the base material to a depth that is shallower than the depth of the groove and more than half of the thickness of the base material, and the rotary cutting tool is moved along the extension line of the second groove portion. By forming the first groove portion having a width wider than the second groove portion,
On the side wall surface of the groove, which is a boundary portion between the first groove portion and the second groove portion, a surface portion of the base material corresponding to the center in the width direction of the groove on the center fracture planned line and an open end of the groove A step portion protruding inward from the connected line is provided.
According to the invention of claim 4, when forming the groove, it is possible to avoid an adverse effect on the appearance,
When opening both door panels, the stepped portions are brought into contact with each other, thereby appropriately controlling the interference between the edge edges of the door panel formed by the side wall surfaces of the grooves, so that the groove that can smoothly break the central fracture line can be easily obtained. Can be formed.

  According to the airbag door of the present invention, it is possible to achieve a smooth break of the planned break line without impairing the appearance of the base material by forming the groove.

  Next, a preferred embodiment of the airbag door according to the present invention will be described below with reference to the accompanying drawings. For convenience of explanation, the same components as those of the airbag door shown in FIG. 7 are denoted by the same reference numerals and detailed description thereof is omitted.

  FIG. 1 is an explanatory view showing an airbag door AD according to an embodiment provided on an instrument panel 10 which is an interior member for a vehicle. The airbag door AD of the embodiment is a base material integrated type that is integrally formed with the base material 12 and always constitutes a part of the base material 12, and includes two door panels 16 provided on the base material 12. , 16 double door type. Further, the back side of the periphery of the opening edge 12a opened in the base 12 when the door panel 16, 16 and the door panel 16, 16 are opened by the backup member 52 including the cylindrical body 52A, the door support member 52B, and the hinge 52C. Has come to support. The airbag door AD breaks from the base material 12 at the door break planned line 30 when the above-described airbag device is actuated and receives the pressing force of the airbag 50, so that each door panel 16, 16 is The base end edge (end portion on the hinge side) 26 is configured to open upward and downward in the drawing around the hinge portion 52C connected through the door support member 52B (see FIG. 1 or FIG. 2). ). In the base material 12, the grooves 18 and 34 constituting the door break planned line 30 are provided so as to open on the back surface side of the base material 12, and the door break planned line 30 is formed from the cabin side which is the design surface (front surface). It cannot be identified.

  The base material 12 is a relatively hard injection-molded member made of a synthetic resin material in which a reinforcing agent is added to, for example, polypropylene (PP) or AS, and has a shape corresponding to the design shape of the instrument panel 10. The door panels 16 and 16 are formed at the same time as part of the substrate 12 when it is formed. The outer contour lines of the door panels 16 and 16 constituting the airbag door AD extend from the front edge 16a side of the door panels 16 and 16 to the side edge 16b side, and extend to the front edge 16a. A substantially sun-shaped door break planned line 30 extending along the parallel base end edge 16c is formed. The door break planned line 30 is formed by cutting the grooves 18 and 34 along the external contour line of the door panel 16 by using a processing device having a rotary cutting tool such as an end mill in a post-process after forming the base material 12. It is a fragile part obtained by doing.

  The door break planned line 30 includes a central fracture planned line 32 extending continuously along a boundary line in both door panels 16 and a side end planned break line extending along the side edges 16b, 16b of the door panel 16. 24 and 24, and the base end fracture | rupture planned line 26 each extended along the base end edge 16c of each door panel 16 is comprised. That is, the central fracture planned line 32 and the proximal fracture planned lines 26, 26 extend in a direction perpendicular to the opening direction of the substantially rectangular door panels 16, 16, and the side fracture planned lines 24, 24 are respectively It extends along the opening direction of the door panel 16.

  As shown in FIG. 2, the central groove (groove) 34 constituting the central planned fracture line 32 opens to the airbag side of the base material 12, and the groove bottom (from the separation width of the open ends 34 a, 34 a of the groove 34 ( The width on the side of the bottom of the groove is narrow. That is, the center fracture planned line 32 is provided on the substrate 12 with a width corresponding to the width of the center groove 34 on the groove bottom side. Further, the central groove 34 is provided with stepped portions 36 and 36 projecting toward the opposite side wall surfaces (inward) at midway portions on the side wall surfaces forming the leading edges 16a and 16a of the door panels 16 and 16, respectively. The step portions 36, 36 are inward from the line connecting the surface portion 33 of the base material 12 corresponding to the center in the width direction of the central groove 34 in the central fracture planned line 32 and the open ends 34 a, 34 a of the central groove 34. And are configured to come into contact with each other when the door panels 16 and 16 are opened. As described above, the central groove 34 is located on the open end side with the stepped portions 36, 36 interposed therebetween, and is relatively wider than the first groove portion 38 and the groove bottom portion side. It is comprised from the 2nd groove part 40 set narrowly. And the step part 36 which connects the 1st groove part 38 and the 2nd groove part 40 is provided in the position biased to the groove bottom part side from the middle of the thickness direction in the base material 12. FIG. That is, the central groove 34 constituting the central fracture line 32 is not set so that the width of the central groove 34 is wide throughout the thickness direction, but only the open end side of the central groove 34 is set wide. In addition, by setting the groove bottom side to be narrow, the door panels 16 and 16 are appropriately configured as a part of the base material 12 before the operation of the airbag device.

  The central groove 34 of the embodiment is a two-step square mark, and both side wall surfaces of the first groove portion 38 and the second groove portion 40 are connected in a stepped manner at the step portion 36. That is, the first groove portion 38 is formed with the same width (first groove width) W1 from the open end 34a to the step portion 36 constituting the bottom surface thereof, and the second groove portion 40 is formed from the step portion 36 to the bottom surface thereof. They are formed with the same width (second groove width) W2. In addition, the bottom surface of the first groove portion 38 and the bottom surface of the second groove portion 40 (the bottom surface of the central groove 34) are formed substantially parallel to the extending surface of the base material 12 and flat, and the residual thickness inspection of the base material 12 is performed. Simplification is achieved. Further, the second groove portion 40 is opened along the extending line of the first groove portion 38 at the center portion in the width direction on the bottom surface of the first groove portion 38, and the side wall surface constituting the central groove 34 has the central groove 34. It has a symmetrical shape on both sides. The first groove width W1 of the first groove portion 38 is set, for example, in the range of 1.0 mm to 5.0 mm, while the second groove width W2 of the second groove portion 40 is narrower than the first groove width W1. It is set in the range of 0.5 mm to 2.5 mm.

  The central groove 34 has a groove depth such that, for the base material 12 having a thickness T of, for example, 2.5 mm to 3.5 mm, the central fracture line 32 remains with a remaining thickness of 0.3 mm to 1.0 mm. F is set, and the depth (first depth) F1 of the first groove portion 38 is set to be not less than half of the thickness T of the base material. The depth (second depth) F2 of the second groove portion 40 from the bottom surface of the first groove portion 38 to the bottom surface of the second groove portion 40 is equal to the remaining thickness (T-F1) and the first depth F1. Set from relationship. Here, the dimension from the open end of the central groove 34 to the step part 36 is the same as the first depth F1 of the first groove part 38.

  In the airbag door AD of the embodiment, the expected door break line 30 is preferably formed by milling using an end mill (rotary cutting tool) 60 as shown in FIG. Here, in particular, the central groove 34 constituting the central fracture planned line 32 is formed with the first groove portion 38 first, and the second groove portion 40 is formed at the bottom of the first groove portion 38 later. First, the end mill 60 equipped with the first cutting blade 60a having a flat front end surface and capable of cutting square marks having the first groove width W1 is started to cut corresponding to one end portion of the center fracture planned line 32. At a point, it cuts in from the one surface of the base material 12 by the 1st depth F1 (refer Fig.3 (a)). From this point, the cutting proceeds so as to reach the cutting end point corresponding to the other end portion of the center fracture planned line 32, and the first groove portion 38 having the first groove width W1 is formed at the first depth F1 (FIG. 3 (b)).

  Next, the first cutting blade 60a in the end mill 60 is replaced with a second cutting blade 60b having a flat tip surface and capable of cutting square marks having the second groove width W2. Then, at the cutting start point or the cutting end point (cutting start point in the embodiment), a cut is made at the second depth F2 from the bottom surface to the center in the width direction of the bottom surface of the first groove portion 38 (FIG. 3C). reference). From here, the cutting is advanced to reach the cutting end point or the cutting start point (cutting end point in the embodiment), and the second groove portion 40 having the first groove width W2 is formed at the second depth F2 ( As shown in FIG. 3D, the step-like central groove 34 is processed. In this way, by forming the central groove 34 by the end mill 60, the groove widths on the open end side and the groove bottom side are different, and the process of providing the step portions 36, 36 at the boundary portion can be easily performed. In addition, since the width of the surface side of the base material 12 in the central groove 34 is set to be narrow, thermal history and the like are suppressed, and the appearance is deteriorated due to deformation of the instrument panel 10 due to this. Absent. Then, the first groove 38 is formed first, and the second groove 40 is formed at the bottom of the first groove 38 later, so that the second is inferior in strength and durability compared to the thick first cutting blade 60a. The burden on the cutting blade 60b can be reduced.

  In the airbag door AD of such an embodiment, when the airbag device is activated, the groove bottom of the central groove 34 connecting the door panels 16 and 16 is pressed by the airbag 50 at the initial stage. It bends and deforms around the surface portion 33 of the base material 12 corresponding to the middle portion of the groove bottom portion, that is, the center in the width direction of the most weakened central groove 34 in the center fracture planned line 32. Accordingly, the side wall surfaces of the central groove 34 (the leading edges 16a and 16a of the door panels 16 and 16) are displaced in directions close to each other about the center fracture planned line 32. Therefore, the step portions 36 and 36 come into contact with each other before the open ends 34a and 34a of the central groove 34 come into contact with each other. Moreover, in the central groove 34, the step portions 36, 36 are located closer to the bent portion than the open ends 34a, 34a, so that the allowable displacement angle of each door panel 16 until it abuts each other can be increased. The timing at which 16a and 16a interfere with each other can be delayed.

  When the stepped portions 36 and 36 come into contact with each other, like a “lever” having both the stepped portions 36 and 36 as fulcrums and the surface portion 33 of the base material 12 at the central fracture line 32 that is a bent portion. A force acts to break the central fracture line 32. That is, since the contact point of the step portions 36 and 36 serving as the fulcrum is in a position close to the central fracture planned line 32 serving as the action point, a force can be effectively applied to break the central fracture planned line 32. And the energy required for breakage can be minimized. As described above, in the initial opening stage of the door panels 16 and 16, the timing at which the front edges 16a and 16a interfere with each other is delayed, and when the step portions 36 and 36 come into contact with each other, Since the force effectively acts so as to break the planned break line 32, the central planned break line 32 is smoothly broken as the airbag 50 is deployed. Next, along with the opening displacement of each door panel 16, the side end break planned lines 24, 24 along the panel opening direction are broken, and the base end break planned line 26 is also broken to open the door panels 16, 16. The airbag 50 is smoothly deployed.

(Example of change)
(1) In the embodiment, the first groove portion is formed first, and the second groove portion is formed at the bottom of the first groove portion later. However, the second groove portion is formed first, and the first groove portion is formed later. May be. That is, as shown in FIG. 4 (a), an end mill (rotary cutting tool) 60 equipped with a second cutting blade 60b having a flat tip surface and capable of cutting a square mark having a second groove width W2 is provided. Cut from the outer surface (one surface) of the substrate 12 to a depth F of the central groove (groove) 34. In this state, by moving the end mill 60 along the boundary line between the door panels 16 and 16, the second groove portion 40 having a relatively narrow second groove width (width) W2 is formed. Then, the second cutting blade 60b of the end mill 60 is replaced with a first cutting blade 60a having a flat tip surface and capable of cutting square marks having the second groove width W2, and the first cutting blade 60a. Is cut from the outer surface of the substrate 12 to a first depth (depth) F1 which is shallower than the depth F of the central groove 34 and more than half of the thickness T of the substrate 12 (see FIG. 4B). . In this state, the end mill 60 is moved along the extending line of the second groove portion 40 to form the first groove portion 38 having the first groove width (width) W1 wider than the second groove portion 40, so that A central groove 34 having stepped portions 36 and 36 can be formed at the boundary portion between the first groove portion 38 and the second groove portion 40 on the wall surface. As in the first embodiment, the stepped portions 36 and 36 are formed by the surface portion 33 of the base material 12 corresponding to the center in the width direction of the central groove 34 in the central fracture planned line 32 and the open ends 34 a and 34 a of the central groove 34. It protrudes inward from the line connecting.
(2) In the embodiment, the opposing side wall surfaces of the first groove portion and the second groove portion constituting the central groove are both formed in parallel, but the groove width increases as one or both of these side wall surfaces go to the open end side. You may comprise so that it may expand. FIG. 5 is a cross-sectional view showing the central fracture line 32 in the airbag door AD1 according to the modified example. In the central groove 34 constituting the central fracture line 32, the second groove portion 40 is the same as in the embodiment. The first groove portion 38 is formed such that the groove width increases as the first groove portion 38 extends from the step portion 36 toward the open ends 34a, 34a, and the side wall surface is inclined. FIG. 6 is a cross-sectional view showing a central fracture line 32 in the airbag door AD2 according to another modification. In the central groove 34 constituting the central fracture line 32, the first groove 38 is a stepped part. The groove width widens from 36, 36 toward the open ends 34a, 34a, and the second groove portion 40 expands from the bottom surface toward the step portions 36, 36, and the side wall surfaces of both groove portions 38, 40 are inclined. To be formed.
(3) In the example and the modified example, when the first groove portion and the second groove portion constituting the central groove are formed, the cutting blades matched to the first groove width and the second groove width of the first groove portion are used. The first groove width or the second groove portion may be formed by reciprocating a cutting blade that forms a width smaller than the first groove width and the second groove width a required number of times.

It is explanatory drawing which showed the double-opening type airbag door which concerns on the Example provided in the instrument panel. It is AA sectional drawing of FIG. 1, Comprising: (a) shows the condition before the action | operation of an airbag apparatus, (b) shows the initial stage in which the door panel is pushed up by the airbag, (c ) Indicates the situation where the fracture occurred at the center fracture line. It is a state figure which shows an example of the formation method of the airbag door of an Example for every step. It is a state figure which shows another example of the formation method of the airbag door of an Example for every step. It is sectional drawing which shows the center fracture line of the airbag door which concerns on the example of a change. It is sectional drawing which shows the center fracture line of the airbag door which concerns on another modification. It is explanatory drawing which showed the conventional double opening type airbag door implemented in the instrument panel. In the conventional airbag door, (a) shows the situation of the door panel immediately after the start of the operation of the airbag device, (b) shows the situation where the fracture starts at the center fracture planned line, (c) shows the door panel It is the schematic which shows the condition open | released. It is sectional drawing which shows the center fracture plan line in the conventional airbag door, Comprising: (a) shows the condition before the operation | movement of an airbag apparatus, (b) is the condition of the door panel immediately after the operation start of an airbag apparatus. Indicates.

Explanation of symbols

10 instrument panels (vehicle interior parts), 12 base materials, 16 door panels,
32 Central fracture line, 33 Surface, 34 Central groove (groove), 34a Open end,
36 steps, 38 first groove, 40 second groove, 60 end mill (rotary cutting tool),
F1 first depth (depth), F2 second depth (depth), T thickness, W1 first groove width (required width),
W2 Second groove width (narrow width)

Claims (4)

An air bag having a groove (34) forming a central fracture line (32) in a boundary line of two door panels (16, 16) provided on a base material (12) constituting a vehicle interior member (10) At the door
The groove (34) is set so that the bottom width is narrower than the separation width of the open ends (34a, 34a), and the groove in the center fracture planned line (32) is located in the middle of the side wall surface ( Step part (36) projecting inward from the line connecting the surface part (33) of the base material (12) corresponding to the center in the width direction of 34) and the open end (34a, 34a) of the groove (34). , 36).   The groove (34) is set to a required width (W1), and includes a first groove portion (38) forming an open end side of the groove (34) and a narrower width (W2) than the first groove portion (38). And the step portion formed at the boundary portion between the first groove portion (38) and the second groove portion (40), the second groove portion (40) forming the bottom side of the groove (34). 2. The airbag door according to claim 1, wherein (36,36) is provided at a portion biased toward the bottom of the groove (34) from the middle in the thickness direction of the base material (12). An air bag having a groove (34) forming a central fracture line (32) in a boundary line of two door panels (16, 16) provided on a base material (12) constituting a vehicle interior member (10) A method of forming a door,
A rotary cutting tool (60) is cut from one surface of the base material (12) to a depth (F1) of more than half of the thickness (T) of the base material (12), and the rotary cutting tool (60) is cut into the boundary. By moving along the line, the first groove (38) of the required width (W1) is formed,
The rotary cutting tool (60) is cut to the required depth (F2) from the bottom surface of the first groove (38), and the rotary cutting tool (60) is moved along the extending line of the first groove (38). By doing so, a second groove (40) having a narrower width (W2) than the first groove (38) is formed,
Corresponds to the center of the groove (34) in the width direction of the central fracture line (32) on the side wall surface of the groove (34), which is the boundary between the first groove (38) and the second groove (40). Steps (36, 36) projecting inward from the line connecting the surface portion (33) of the base material (12) and the open ends (34a, 34a) of the groove (34) are provided. A method for forming an air bag door. An air bag having a groove (34) forming a central fracture line (32) in a boundary line of two door panels (16, 16) provided on a base material (12) constituting a vehicle interior member (10) A method of forming a door,
By cutting the rotary cutting tool (60) from one surface of the base material (12) to the depth (F) of the groove (34) and moving the rotary cutting tool (60) along the boundary line, Forming a second groove (40) with a wide width (W2),
A rotary cutting tool (from one surface of the base material (12) to a depth (F1) shallower than the depth (F) of the groove (34) and more than half the thickness (T) of the base material (12) ( 60), and the rotary cutting tool (60) is moved along the extending line of the second groove (40), so that the first groove (W1) wider than the second groove (40) ( 38)
Corresponds to the center of the groove (34) in the width direction of the central fracture line (32) on the side wall surface of the groove (34), which is the boundary between the first groove (38) and the second groove (40). Steps (36, 36) projecting inward from the line connecting the surface portion (33) of the base material (12) and the open ends (34a, 34a) of the groove (34) are provided. A method for forming an air bag door.

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