JP2005178451A - Method for manufacturing air bag door skin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture, by using a simple device, a skin 5 that has a fine appearance without presenting a shape of a groove part 11 to the surface side, and is reliably ruptured in the groove part 11 of the skin at inflation of an air bag in a method for manufacturing the skin 5 in which the groove part 11 is worked in the back side of the skin 5 corresponding to a rapture predetermined part 9 of a vehicle air bag door 13 while the skin 5 is remained in the surface side. <P>SOLUTION: The approximately V-shaped groove part 11 is worked in the back side of the skin 5 by a milling cutter 43 with cutting edges of a first face 45 and a second face 47 crossing at an edge angle α of ≥30° and ≤80° seen from a direction vertical to a main spindle 41. When the single angle milling cutter 43 is used, the main spindle 41 is inclined to be ≥0° and ≤the edge angle α to the back side of the skin 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an airbag door skin, in which a groove portion is processed with a cutting tool on the back surface of the skin corresponding to a planned fracture portion of a vehicle airbag door.

  Conventionally, it is generally known to equip a vehicle with an airbag device for protecting an occupant from an impact at the time of the collision. When the airbag device is mounted on the back side of the instrument panel, an airbag door that is deployed by the inflation pressure of the airbag is provided on the base material. For example, the base material is formed in a frame shape with a planned breakage portion that is weaker than other portions and breaks due to the inflation pressure of the airbag, and a hinge portion that serves as a pivot center for the opening operation of the airbag door. The airbag door is configured by a rectangular region defined by the planned portion and the hinge portion. A groove that is mechanically weak is also provided in the skin covering the base material so as to correspond to the planned fracture portion. In order not to impair the appearance of the surface of the skin, the groove is provided, for example, by using a laser cutter, a heating blade or the like so that the skin is left on the surface side on the back surface of the skin.

  However, in the manufacturing method in which the groove is formed with a laser cutter, a laser processing machine with a high equipment cost must be used, and the running cost is also expensive.

  In addition, in the manufacturing method using a heating blade, the pressure contact mark remains on the surface side during pressure welding, or the heat capacity of the blade tip is too large and deforms due to heat influence around the groove, so the appearance of the skin is poor. Become.

Therefore, there is known a technique in which a perforation cutter, an ultrasonic cutter, or the like is attached to a robot arm to form a groove in the airbag skin (for example, see Patent Document 1).
JP 2000-343486 A

  However, according to the above-described conventional method for manufacturing an airbag door skin, the groove formed by a perforation cutter or an ultrasonic cutter has a flat bottom and is not pointed toward the surface side of the skin. , Stress concentration hardly occurs at the bottom. For this reason, there is a case where the epidermis does not break at a fixed position and hinders inflation of the airbag.

  The present invention has been made in view of the above points, and the object of the present invention is to appropriately select a cutting tool for processing the groove portion on the airbag door skin so that the shape of the groove portion on the surface side is improved. An object of the present invention is to make it possible to easily manufacture a vehicular airbag door skin that does not appear and has a good appearance and breaks reliably at a scheduled breakage portion of the airbag door when the airbag is inflated with a simple device.

  In order to achieve the above object, in the present invention, the groove portion of the epidermis is processed by a milling cutter.

  Specifically, in the invention of claim 1, a method for manufacturing an airbag door skin in which a groove is formed by leaving a skin on the front surface side with a cutting tool on the back surface of the skin corresponding to a planned fracture portion of a vehicle airbag door. Is targeted.

  The cutting tool includes a milling cutter formed such that the first surface and the second surface on which cutting edges are formed intersect each other at a blade angle of 30 ° or more and 80 ° or less when viewed from a direction perpendicular to the main axis. Then, the milling cutter is rotated, and a substantially V-shaped groove portion is processed on the back surface of the skin by the cutting edges of the first surface and the second surface.

  In the invention of claim 2, the first surface of the milling cutter is orthogonal to the main axis, and the main axis is at least 0 ° with respect to the back surface of the skin and between the first surface and the second surface. The inclination angle is set so as to be less than the blade angle.

  In the invention of claim 3, the bisector of the blade angle between the first surface and the second surface of the milling cutter is orthogonal to the main axis, and the main axis is 0 ° or more with respect to the back surface of the skin. In addition, the inclination angle is set so as to be 1/2 or less of the blade angle.

  In the manufacturing method of the airbag door skin of the said invention of Claim 1, it has the cutting edge of the 1st surface and the 2nd surface which cross | intersect with the blade angle of 30 degrees or more and 80 degrees or less seeing from the direction perpendicular | vertical to a main axis | shaft. A substantially V-shaped groove was formed on the back surface of the skin by milling.

  At this time, if the blade angle is smaller than 30 °, the inclination angle of the V-shaped groove portion is increased and the width thereof is narrowed, making it difficult to process the groove portion. On the other hand, if it is larger than 80 °, the V-shaped groove portion is The inclination angle becomes smaller and the thickness in the width direction becomes lighter as a whole. Stress concentration hardly occurs at the bottom of the groove (the deepest bottom of the V-shape), and the shearing force from the deepest bottom is applied to the bottom. It becomes difficult to transmit, and the rupture line of the epidermis is not constant. Moreover, after limiting the blade angle to 30 ° or more and 80 ° or less, a groove portion is formed in a V shape at the tip of two cutting blades formed on the first surface and the second surface of the milling cutter. Therefore, stress concentration occurs at the pointed bottom, the skin can be broken at the bottom, and the airbag door can be reliably deployed, and the expansion of the airbag is not hindered. Further, the shape of the groove can be easily changed by adjusting the shape of the milling cutter and the inclination angle of the main shaft. Therefore, it is possible to easily manufacture a vehicle airbag door skin that has good appearance and that is surely broken at the bottom of the groove when the airbag is inflated with a simple device.

  According to a second aspect of the present invention, a milling machine having a first surface orthogonal to the main axis is used, and the blade between the first surface and the second surface is rotated at 0 ° or more with respect to the back surface of the main shaft to rotate the main shaft. It was made to incline so that it might become below a corner.

  In such a so-called single-angle milling machine, if the inclination angle of the main shaft is smaller than 0 °, the skin and the main shaft interfere with each other and cannot be machined. It becomes difficult to process the groove. Therefore, the groove portion can be easily processed by limiting the inclination angle of the main shaft with respect to the back surface of the skin in this way.

  In the invention of claim 3, a milling machine in which the bisector of the blade angle between the first surface and the second surface is perpendicular to the main axis is used, and the main axis for rotating the milling cutter is 0 ° or more with respect to the back surface of the skin And tilted so as to be ½ or less of the blade angle.

  Even in such a so-called equiangular milling machine, if the inclination angle of the main shaft is smaller than 0 °, the skin and the main shaft interfere with each other, and machining cannot be performed. Becomes under-shaped, making it difficult to process the groove. Therefore, the groove portion can be easily processed by limiting the inclination angle of the main shaft with respect to the back surface of the skin in this way.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the front passenger compartment side of the vehicle. The upper left side in FIG. 1 is the front side of the vehicle, that is, the windshield side, and the lower right side is the rear side, that is, the passenger seat side. An instrument panel 1 having a skin according to the first embodiment of the present invention is disposed at the front of the vehicle interior.

  As shown in FIG. 2, the instrument panel 1 includes a resin base material 3 and a skin 5 integrally bonded to the surface of the base material 3. As shown in detail in FIG. 3, on the back surface of the base material 3, for example, a fracture groove 7 having a V-shaped cross section that is recessed toward the front surface side has four rectangular sides when viewed from the surface side of the instrument panel 1. Of these, each side is formed except for the front side (left side in FIG. 2) (indicated by a broken line in FIG. 1). A thin-walled fracture portion 9 is formed on the surface side of the substrate 3 by the fracture groove 7. A groove portion 11 having a substantially V-shaped cross section is formed on the back surface of the skin 5 corresponding to the planned fracture portion 9 with a part of the skin 5 remaining on the front surface side.

  And by the fracture | rupture of the planned fracture | rupture part 9 by the action | operation of the airbag apparatus 31 mentioned later, it expand | deploys to the vehicle interior side centering on the front side part 9a (it shows with a dashed-dotted line in FIG. 1) which is one side of the front side among the four sides. A rectangular airbag door 13 is formed. The airbag door 13 is configured as a so-called seamless type in which the groove 11 of the skin 5 cannot be identified from the surface side of the instrument panel 1.

  On the back surface of the instrument panel 1, a rectangular plate-shaped reinforcing plate portion 15 integrally welded to the back surface of the airbag door 13, and the airbag bulges with the reinforcing plate portion 15 having a gap. A rectangular frame body 19 formed integrally with the back surface of the base 3 of the instrument panel 1 and a rectangular tube integrally projecting on the back surface of the frame body 19. A cylindrical portion 21 and a hinge portion 23 connecting the front end portion of the reinforcing plate portion 15 to the upper end portion of the front side portion 21a of the cylindrical portion 21 corresponding to the front side portion 9a are integrally formed by injection molding. A frame body 24 is attached.

  A known airbag device 31 is disposed and accommodated inside the cylindrical portion 21. The airbag device 31 includes an airbag case 33 coupled to a vehicle body member (not shown). In the airbag case 33, although not shown, an inflator for injecting high-pressure gas at the time of a vehicle collision, and the inflator And an airbag that is filled with the high-pressure gas from and is inflated from the folded state. An engagement hole 25 is formed in an intermediate portion of the tubular portion 21, and an engagement portion 35 protruding from the side surface of the airbag case 33 is inserted into the engagement hole 25. When the engaging hole 25 and the engaging portion 35 are locked during operation, the cylindrical portion 21 and the like are prevented from protruding into the vehicle compartment together with the airbag.

  Therefore, in the above embodiment, when the airbag device 31 is actuated by the collision of the vehicle and the airbag is inflated from the airbag case 33, the deployment pressure of the airbag is set to the reinforcing plate portion 15 and the reinforcing plate portion 15. Is received by the airbag door 13 of the instrument panel 1 in which the instrument panel 1 is integrally welded, and the planned break portion 9 of the instrument panel 1 is broken, and the skin 5 on the planned break portion 9 is also broken from the groove portion 11. . Then, the airbag door 13 is opened together with the reinforcing plate portion 15 around the hinge portion 23, and is partitioned by the planned breakage portion 9 and the front side portion 9 a at the trace of the airbag door 13 of the instrument panel 1 to the shooting port 17. An opening for communication is generated, and the airbag is deployed in the vehicle interior through the shooting port 17 or the opening of the instrument panel 1.

-Manufacturing method of epidermis-
Next, the manufacturing method of the skin 5 which concerns on Embodiment 1 of this invention which processes the groove part 11 to the said skin 5 is demonstrated.

  As shown in FIG. 4, first, the skin 5 is placed on a milling machine (not shown). A first surface 45 and a second surface 47, each having a cutting edge, are perpendicular to the main shaft 41 (that is, the front side of the drawing) of the main shaft (rotating shaft for rotating the milling cutter 43) 41 of the milling machine. A milling cutter 43 formed so that the blade angle α viewed from the crossing at 60 ° is attached.

  The milling cutter 43 is a so-called single-angle milling cutter whose first surface 45 is orthogonal to the main shaft 41. The main shaft 41 is set so that the inclination angle β is 30 ° with respect to the back surface of the skin 5.

  Then, while rotating the milling cutter 43 by the main shaft 41, it moves on the back surface of the skin 5 so as to correspond to the planned breaking portion 9, and the groove 11 is processed with the skin 5 remaining on the front surface side (lower side in the figure). By setting the blade angle α and the inclination angle β as described above, the groove portion 11 having a V-shaped cross section with a sharp bottom is formed.

  Further, as shown in FIG. 5, when the inclination angle β is 60 °, a groove 11 having a vertical right side wall is formed, and when the inclination angle β is 0 ° as shown in FIG. A groove 11 having a vertical left side wall is formed.

  In this way, the shape of the groove 11 can be easily changed by changing the inclination angle β of the main shaft 41.

  The blade angle α can be set to 30 ° or more and 80 ° or less (30 ° ≦ α ≦ 80 °). When the blade angle α is smaller than 30 °, the inclination angle of the V-shaped groove portion 11 is increased and the width thereof is narrowed, so that the processing of the groove portion 11 is difficult. On the other hand, when the blade angle α is larger than 80 °, the V-shaped groove portion. 11 and the thickness in the width direction becomes lighter as a whole, stress concentration hardly occurs at the bottom of the groove 11 (the deepest bottom of the V shape), and the shearing force from the deepest bottom is the bottom. The break line of the skin 5 is not constant. In addition, the groove angle 11 is V-shaped at the tip of the two cutting edges formed on the first surface 45 and the second surface 47 of the milling cutter 43 after the blade angle α is limited to 30 ° or more and 80 ° or less. Therefore, stress concentration occurs at the pointed bottom portion, and the skin can be broken at the bottom portion, so that the airbag door 13 can be reliably deployed, and the expansion of the airbag is not hindered.

  The inclination angle β can be set to 0 ° or more and a blade angle α or less (0 ≦ β ≦ α). If the inclination angle β of the main shaft 41 is smaller than 0 ° (see FIG. 6), the main shaft 41 and the skin 5 interfere with each other to make it impossible to process the groove portion 11, and the inclination angle β is equal to the blade angle α. If it is larger than the case (see FIG. 5), the bottom of the groove 11 becomes an under shape, and the processing of the groove 11 becomes difficult.

  Therefore, according to the manufacturing method of the airbag door skin according to the first embodiment, the shape of the groove portion 11 does not appear on the surface side, and the appearance is good, and the airbag 11 is reliably broken at the sharp bottom portion of the groove portion 11 when the airbag is inflated. The skin 5 of the airbag door for a vehicle to be manufactured can be easily manufactured with a simple device.

(Embodiment 2)
FIG. 7 shows Embodiment 2 of the present invention, which differs from Embodiment 1 in that the shape of the milling cutter 43 is different. In the present embodiment, the same portions as those in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 7 shows a so-called equiangular milling cutter 43 in which the blade angle α between the first surface 45 and the second surface 47 is 60 ° and the bisector 48 of the blade angle α is orthogonal to the main axis 41. In this figure, the main shaft 41 is inclined with respect to the back surface of the skin 5 so that the inclination angle β is 0 °.

  In this equiangular milling machine 43, the inclination angle β of the main shaft 41 with respect to the back surface of the skin 5 is 0 ° shown in FIG. 7 to 30 ° shown in FIG. 8, that is, ½ or less of the blade angle α (0 ≦ β ≦ 1 / 2α). Can be set to If the inclination angle β of the main shaft 41 is smaller than 0 ° (see FIG. 7), the main shaft 41 and the skin 5 interfere with each other to make it impossible to process the groove portion 11, and the inclination angle β is set to the blade angle α. If it is larger than 1/2 (see FIG. 8), the bottom of the groove 11 becomes an under shape, making it difficult to process the groove 11. By limiting in this way, the same effects as those of the first embodiment can be obtained.

(Other embodiments)
The present invention may be configured as follows for each of the above embodiments.

  In each said embodiment, although the instrument panel 1 was comprised with the base material 3 and the skin 5, you may provide a foaming layer between these base materials 3 and the skin 5. FIG.

  Although the shape of the milling cutter 43 is a single-angle milling cutter in the first embodiment and is an equiangular milling cutter in the second embodiment, the shape of the milling cutter 43 is not limited to these. The point is that the milling cutter 43 has a first surface and a second surface on which cutting edges are formed, respectively, and a blade angle α of 30 ° ≦ α ≦ 80 ° may be selected.

  In each of the above embodiments, the airbag door 13 is provided on the instrument panel 1, but the present invention is not limited to this, and the airbag door may be attached to a steering wheel (handle) of a vehicle other than the instrument panel 1, for example. May be provided.

  As described above, the present invention is useful for a method for manufacturing a skin in which a groove is formed on the back surface of the skin corresponding to a planned fracture portion of a vehicle airbag door.

It is a perspective view which shows the vehicle interior front part of the front passenger seat in the vehicle which concerns on Embodiment 1 of this invention. It is the II-II line expanded sectional view of FIG. It is the A section expanded sectional view of FIG. It is an expanded sectional view which shows a mode that a skin is processed with the manufacturing method of the airbag door skin which concerns on Embodiment 1. FIG. FIG. 5 is a view corresponding to FIG. 4 when the inclination angle β of the main shaft is 60 °. FIG. 5 is a view corresponding to FIG. 4 when the inclination angle β of the main shaft is 0 °. It is an expanded sectional view which shows a mode that a skin is processed with the manufacturing method of the airbag door skin which concerns on Embodiment 2. FIG. FIG. 8 is a view corresponding to FIG. 7 when the inclination angle β of the main shaft is 30 °.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Base material 5 Skin 7 Breaking groove 9 Breaking part 11 Groove part 13 Airbag door 41 Main axis 43 Milling 45 First surface 47 Second surface

Claims (3)

A method for manufacturing an airbag door skin, in which a groove is formed by leaving a skin on the surface side by using a cutting tool on the back surface of the skin corresponding to a planned fracture portion of a vehicle airbag door,
The cutting tool includes a milling cutter formed such that the first surface and the second surface on which cutting edges are formed intersect each other at a blade angle of 30 ° or more and 80 ° or less when viewed from a direction perpendicular to the main axis. Become
A method of manufacturing an airbag door skin, wherein the milling machine is rotated, and a substantially V-shaped groove is formed on the back surface of the skin by the cutting edges of the first surface and the second surface. In the manufacturing method of the airbag door skin of Claim 1,
The first surface of the milling cutter is orthogonal to the main axis;
The airbag is characterized in that an inclination angle is set so that the main shaft has an angle of 0 ° or more with respect to the back surface of the skin and not more than the blade angle between the first surface and the second surface. Manufacturing method of door skin. In the manufacturing method of the airbag door skin of Claim 1,
The bisector of the blade angle between the first surface and the second surface of the milling cutter is perpendicular to the main axis;
The manufacturing method of an airbag door skin, wherein the inclination angle is set so that the main shaft is 0 ° or more and 1/2 or less of the blade angle with respect to the back surface of the skin.

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