Heater for airbag device

Abstract

To provide a heater for an airbag device which can also be used in an existing airbag device and suppresses an increase in manufacture cost or the like.SOLUTION: A heater for an airbag device includes a sheet-type heater body 55 disposed to cover a cabin inside surface side of an airbag cover of an airbag device. The heater body is formed of a woven fabric 56 having flexibility, and has heat dissipation means. A division planned part 58 capable of being divided when a door part is opened is disposed at a position corresponding to a rupture planned part of the airbag cover. The division planned part includes: a main slit 59 intermittently provided substantially along the rupture planned part; and sub slits 60 disposed on the sides of the main slit. The sub slits are disposed in the woven fabric so as to break warp yarns VT or weft yarns HT which constitute a portion of a coupling part 62 formed between parts of the main slit.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a heater for an airbag device that is disposed so as to cover the interior surface side of an airbag cover in an airbag device and is capable of radiating radiant heat to an occupant in the vehicle compartment. [Background technology]

[0002] Conventionally, there has been a heater for an airbag device that includes an interior panel equivalent to an airbag cover in an airbag device, a heater main body disposed on the interior surface side of the interior panel, and a skin layer that covers the heater main body (see, for example, Patent Document 1). In this conventional heater for an airbag device, the skin layer that covers the heater main body is made of woven fabric or knitted fabric. In order to smoothly break the skin layer when the interior panel is opened, the outer shape of a tear portion (a portion to be broken) provided on the interior panel as viewed from the interior panel surface side is made to be zigzag or have a shape in which concaves and convexes are alternately connected, so that when the tear portion breaks, stress is locally concentrated on the skin layer, causing the skin layer to break. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 116679 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional airbag heaters, the shape of the tear portion of the interior panel (the component equivalent to the airbag cover in a normal airbag device) was changed to make it easier to open the component (skin layer) on the heater side when the airbag inflates. Therefore, for example, it could not be easily installed in a conventional airbag device, and it was necessary to change the design of the airbag device itself (specifically, the airbag cover).

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made to solve the above-mentioned problems, and has an object to provide a heater for an airbag device that can be easily used with a conventional airbag device and that can suppress increases in manufacturing costs, etc. [Means for solving the problem]

[0006] The heater for an airbag device according to the present invention comprises an airbag that is folded and stored in a storage area; An airbag cover is arranged to cover the airbag and has a door portion that can be opened by breaking a breakable portion arranged on the periphery when the airbag is deployed and inflated; The present invention is used in an airbag device having A heater for an airbag device, which is arranged to cover an interior surface side of an airbag cover and is capable of radiating radiant heat to an occupant in the vehicle interior, The heater body is disposed so as to cover the interior surface side of the airbag cover, and is configured to generate heat and emit radiant heat. the heater body is made of a flexible woven fabric, has a heat generating means, and is configured to have a breakable portion that can be broken when the door portion is opened, at a position corresponding to the breakable portion formed on the airbag cover; The intended breaking portion includes a main slit provided intermittently so as to substantially follow the intended breaking portion, and a sub-slit disposed on at least one side of the main slit, The sub-slits are arranged so as to cut the warp or weft threads constituting the connecting portion formed between the main slits in the woven fabric.

[0007] In the heater for an airbag device of the present invention, the heater body arranged to cover the interior surface side of the airbag cover is made of a flexible woven fabric, and the heater body is formed with a planned rupture portion at a position corresponding to the planned rupture portion formed in the airbag cover, the planned rupture portion being rupturable when the door portion opens during deployment and inflation of the airbag. The planned rupture portion is configured to include a main slit provided intermittently so as to be substantially aligned with the planned rupture portion, and a sub-slit disposed on at least one side of the main slit, and the sub-slit is arranged in the woven fabric so as to cut the warp or weft threads constituting the portion of the connection portion formed between the main slits. In other words, in the heater for an airbag device of the present invention, the warp or weft threads constituting the region covering the vicinity of the planned rupture portion of the airbag cover in the heater body are previously divided by the main slit and the sub-slit constituting the planned rupture portion. Therefore, even in a configuration having a heater body made of woven fabric, when the airbag inflates (when the rupture portion ruptures), the heater body can be quickly ruptured at the location of the rupture portion, and after rupture, the heater body can be moved together with the door portion that opens, allowing the airbag to inflate without hindrance. In the heater for an airbag device of the present invention, the woven fabric constituting the heater body is provided with a main slit and a sub slit, which enables the door portion of the airbag cover and the heater body to be quickly opened, so there is no need to change the design of the rupture portion provided in the airbag cover, and the heater can be easily used in conventional airbag devices.

[0008] Therefore, the heater for an airbag device of the present invention can be easily used in a conventional airbag device, and an increase in manufacturing costs, etc. can be suppressed.

[0009] Specific examples of the heater body include a structure in which a woven fabric is used as a base material and carbon nanotubes are supported on this base material as a heat generating means, and a woven fabric formed by weaving carbon nanotubes themselves.

[0010] In addition, the woven fabric constituting the heater body may be, for example, arranged in a bias manner so that the warp threads and the weft threads are inclined with respect to the intended rupture portion of the airbag cover.

[0011] When the woven fabric constituting the heater body is arranged in a bias pattern, it is preferable to arrange the sub-slits on both sides of the main slit, with one of them cutting one of the warp or weft threads constituting the connecting portion and the other cutting the other of the warp or weft threads constituting the connecting portion. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic longitudinal sectional view in the front-rear direction of a vehicle showing a state in which a knee-protecting airbag device using a heater according to an embodiment of the present invention is used. [Diagram 2] 2 is a schematic enlarged longitudinal sectional view of the knee-protection airbag device of FIG. 1 taken in the vehicle front-rear direction. [Diagram 3] 2 is a schematic cross-sectional view of the knee-protection airbag device of FIG. 1 taken in the left-right direction of the vehicle. [Figure 4] 2 is a schematic front view of the knee-protection airbag device of FIG. 1 when used, seen from the rear of the vehicle. FIG. [Diagram 5] 1 is a schematic cross-sectional view of a heater according to an embodiment. [Figure 6] 2 is a schematic rear view (viewed from the rear surface side) showing a heater main body and an electrode portion in the heater according to the embodiment. FIG. [Figure 7] FIG. 4 is a partially enlarged plan view showing a portion of a substrate in a heater body according to the embodiment, the portion being to be divided. [Figure 8] FIG. 2 is a partially enlarged schematic cross-sectional view of a heater body according to the embodiment. [Figure 9] 2 is a schematic enlarged longitudinal sectional view in the vehicle front-rear direction, showing a state in which the airbag has completed inflation in the knee-protection airbag device of FIG. 1. FIG. [Figure 10] FIG. 11 is a partially enlarged plan view of a base material constituting a heater body according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below with reference to the drawings. In the embodiment, an airbag device heater (hereinafter simply abbreviated as "heater") H used in a knee protection airbag device (hereinafter simply abbreviated as "airbag device") M will be taken as an example and described. As shown in FIG. 1, the airbag device M is disposed in an area below a steering column 8 on the vehicle front side of a driver D so as to be capable of protecting the knees K (KL, KR) of an occupant (driver D) seated in a seat (in the embodiment, the driver's seat). In the embodiment, the up-down, left-right, and front-rear directions correspond to the up-down, left-right, and front-rear directions of a vehicle when the airbag device M is mounted on the vehicle, unless otherwise specified.

[0014] As shown in Figures 2 and 3, the airbag device M comprises a folded airbag 30, an inflator 10 that supplies inflation gas to the airbag 30, a case 20 as a storage area for storing the folded airbag 30 and the inflator 10, a retainer 15 for holding the inflator 10 and attaching the inflator 10 and the airbag 30 to the case 20, an airbag cover 35 that covers the folded airbag 30, and a heater H arranged to cover the interior surface side (rear side) of the airbag cover 35.

[0015] 2 and 3, the inflator 10 is generally cylindrical with its axial direction generally aligned in the left-right direction, and in this embodiment, a gas discharge section 10a having a number of gas discharge ports (reference numbers omitted) capable of discharging inflation gas is disposed on the left end side. A connector 11 is connected to the right end side of the inflator 10, to which a lead wire 12 for inputting an activation signal extending from a control device (not shown) is connected.

[0016] 2 and 3, the retainer 15 that holds the inflator 10 includes a substantially cylindrical holding portion 16 that covers the outer periphery of the inflator 10, and two bolts 17, 17 that protrude substantially perpendicular to the axial direction of the holding portion 16. In the airbag device M of the embodiment, when the inflator 10 is housed in the holding portion 16 of the retainer 15 that is disposed in the airbag 30 and the airbag 30 is housed in the case, the bolt 17 of the retainer 15 is caused to protrude from the bottom wall portion 21 of the case 20, and a nut 18 is fastened to the bolt 17, thereby attaching the inflator 10 and the airbag 30 to the case 20.

[0017] The case 20 as the storage portion is made of sheet metal, and has a bottom wall portion 21 of a substantially rectangular tubular shape arranged on the vehicle front side, and a peripheral wall portion 22 of a substantially rectangular tubular shape extending rearward from the periphery of the bottom wall portion 21, and is substantially box-shaped with a protrusion opening 20a through which the airbag 30 can protrude at the rear end side of the peripheral wall portion 22, as shown in Figs. 2 and 3. In the case of the embodiment, the case 20 is formed to be wide in the left and right directions, and the peripheral wall portion 22 has locking claw portions 22c at the rear end sides of the upper wall 22a and the lower wall 22b opposed to each other in the vertical direction for locking mounting pieces 44U, 44D of the airbag cover 35, which will be described later. Although detailed illustration is omitted, the locking claw portions 22c are formed in a plurality of pieces along the left and right direction. Although detailed illustration is omitted, mounting brackets 24, 25 for mounting the case 20 to the body 1 are disposed on both left and right ends of the upper wall 22a and the lower wall 22b of the case 20 as shown in Fig. 4. The mounting bracket 24 provided on the upper wall 22a side is connected to brackets 4, 4 extending from the instrument panel reinforcement on the body 1 side as shown in Fig. 4. The mounting bracket 25 provided on the lower wall 22b side is connected to brackets 5, 6 extending from a center brace or a front body pillar (not shown) on the body 1 side as shown in Fig. 4.

[0018] The airbag 30 is bag-shaped and made of flexible woven fabric made of polyamide yarn, polyester yarn, etc., and is configured so that when fully inflated, it has a roughly rectangular plate-like shape, as shown by the dotted line in Figures 1 and 4, and is capable of protecting the left and right knees K (KL, KR) of the driver D.

[0019] The airbag cover 35 is disposed so as to cover the vehicle rear side of the airbag 30 folded and stored in the case 20, and is specifically configured to be able to cover the vehicle rear side of the case 20. The airbag cover 35 is formed of a thermoplastic elastomer such as a polyolefin-based elastomer, and in the case of the embodiment, as shown in FIG. 4, is disposed at a position below the steering column 8 as viewed from the vehicle rear side, on the side of the lower panel 9b of the instrument panel (hereinafter abbreviated as "instrument panel") 9 composed of an upper panel 9a and a lower panel 9b. In addition, as shown in FIG. 1, the airbag cover 35 is disposed at a position in front of the knees K of the driver D seated in the driver's seat. In the case of the embodiment, the airbag cover 35 includes a door arrangement portion 36 disposed near the projection opening 20a of the case 20, and a peripheral portion 47 extending around the door arrangement portion 36.

[0020] The door installation portion 36 includes two door portions 37U, 37D arranged side by side at the top and bottom so as to cover the protrusion opening 20a of the case 20, a breakable portion 39 and a hinge portion 42 arranged around the door portions 37U, 37D, and mounting pieces 44U, 44D extending forward from the upper end side of the upper door portion 37U and the lower end side of the lower door portion 37D, respectively. The two door portions 37U, 37D cover the vehicle rear side of the protrusion opening 20a and are configured to open to both the top and bottom when opened. The breakable portion 39 arranged around the door portions 37U, 37D is substantially H-shaped when viewed from the vehicle rear side (see FIG. 4). The breakable portion 39 is formed by recessing the door installation portion 36 from the back side (the vehicle front side), and in the case of the embodiment, as shown in Figs. 2 and 3, the door installation portion 36 is recessed into a substantially V-shaped cross section. The breakable portion 39 is configured by continuously arranging such recesses over the entire length. To explain the breakable portion 39 in detail, it includes a horizontal bar portion 39a arranged in a straight line substantially along the left-right direction between the door portions 37U and 37D, and two vertical bar portions 39b, 39b arranged on the left and right sides of the upper and lower door portions 37U and 37D so as to extend vertically from the horizontal bar portion 39a. Each vertical bar portion 39b is linearly shaped substantially along the vertical direction so as to be substantially perpendicular to the horizontal bar portion 39a (see Fig. 4). 2, the hinge portion 42 is disposed on the upper end side of the upper door portion 37U and the lower end side of the lower door portion 37D. Each door portion 37U, 37D opens with the hinge portion 42 as a rotation center when opening. The mounting piece portions 44U, 44D are disposed adjacent to the outer periphery sides of the upper wall 22a and the lower wall 22b of the case 20, respectively, so as to protrude toward the front side of the vehicle, and include locking hole portions 44a for locking the locking claw portions 22c formed in the case 20.

[0021] The peripheral portion 47 is configured in a stepped shape on both the left and right sides of the door mounting portion 36 so as to be located one step further forward in the vehicle than the door portions 37U, 37D, and is configured to support the portions of the lower panel 9b located on both the left and right sides of the door portions 37U, 37D so as to make the vehicle rearward surfaces of the door portions 37U, 37D and the lower panel 9b approximately flush (see Figure 3).

[0022] The heater H, which is disposed so as to cover the interior surface side (rear side) of the airbag cover 35, is capable of radiating radiant heat to an occupant in the vehicle interior (in the case of the embodiment, the driver D seated in the driver's seat) when activated. In the case of the embodiment, the heater H is disposed so as to cover substantially the entire rear side of the door installation portion 36 in the airbag cover 35, as shown in Figs. 2 and 3. The heater H is entirely in the form of a flexible sheet, and in the case of the embodiment, the overall thickness is set to about 20 µm to 2 mm.

[0023] 5, the heater H includes a heater body 55 formed in a sheet shape, an electrode portion 50 disposed around the heater body 55, a heat insulating layer 51 disposed on the front side (airbag cover 35 side) when mounted on the vehicle, and a coating layer 70 disposed on the rear side (driver D side) when mounted on the vehicle. The heater body 55 and the electrode portion 50 are integrated with the heat insulating layer 51 by interposing an adhesive layer 52 therebetween. In the case of the embodiment, the heater H has an outer shape that is substantially the same as the outer shape of the door mounting portion 36 of the airbag cover 35 when viewed from the rear side of the vehicle, and is shaped to be able to cover substantially the entire rear side of the door mounting portion 36, and more specifically, is shaped like a substantially rectangular plate that is wide on both sides.

[0024] In the embodiment, the electrode portion 50 is made of a metal foil (specifically, copper foil in the embodiment) formed in a band shape. In the embodiment, the electrode portion 50 is continuously disposed over substantially the entire area on the left and right sides at the upper end side and the lower end side of the heater H (heater body 55) (see FIG. 6). In the embodiment, as shown in FIG. 5, the electrode portion 50 is disposed so as to overlap the surface (back surface 55d side) of the airbag cover 35 at the upper edge 55a side and the lower edge 55b side of the heater body 55. Note that, in FIG. 5, a step is shown as being generated by the thickness of the electrode portion 50, but in reality, the electrode portion 50 is thin and such a step is hardly generated. Each electrode portion 50 is disposed at a position above or below the door portions 37U and 37D (at a position not overlapping the breakable portion 39) when mounted on the vehicle. Each electrode unit 50 is electrically connected to a control device (not shown) via a lead wire 50a (see FIG. 6) extending from one end of the electrode unit 50. When energized, the electrode unit 50 generates heat itself and also energizes carbon nanotubes (described later) as heat generating means provided in the heater body 55, thereby generating heat.

[0025] The heat insulating layer 51 is for reflecting heat generated when the electrode unit 50 is energized while suppressing the heat from being transmitted to the airbag cover 35 side, and for efficiently radiating the heat to the driver D side. In the case of the embodiment, the heat insulating layer 51 is formed from a nonwoven fabric having aluminum foil (metal foil) vapor-deposited on one side, and is arranged so that the aluminum foil is positioned on the heater main body 55 side, although detailed illustration is omitted. As shown in FIG. 5, the heat insulating layer 51 is arranged so as to cover almost the entire vehicle front side (airbag cover 35 side) of the heater main body 55 and the electrode unit 50. The material for forming the heat insulating layer 51 is not limited to the embodiment. As the heat insulating layer, a material in which metal foil is vapor-deposited on a base material such as glass fiber, silica fiber, fluorine fiber, BASHFIBER (registered trademark) or other fiber or urethane foam can also be used.

[0026] The heater body 55 has a heat generating means and is formed of a flexible woven fabric. In the embodiment, the heater body 55 is configured such that the woven fabric is used as the base material 56, and the base material 56 carries carbon nanotubes as the heat generating means. The heater body 55 has an outer shape that is substantially the same as the outer shape of the heater H, that is, the heater body 55 has a shape that is substantially the same as the outer shape of the door mounting portion 36 of the airbag cover 35 when viewed from the rear side of the vehicle, and is capable of covering the entire rear side of the door mounting portion 36. That is, the heater body 55 (base material 56) has an outer shape that is substantially rectangular and wide on the left and right sides, as shown in FIG. 6.

[0027] In the embodiment, the base material 56 is a woven fabric made of raw yarns made of polyamide yarns or polyester yarns woven by plain weaving. More specifically, as shown in FIG. 7, the base material 56 is a fabric cut into a predetermined shape with the threads (warp yarns VT and weft yarns HT) of the woven fabric aligned in the bias direction (intersecting at an angle of 45°). That is, the base material 56 is arranged in a bias shape so that the warp yarns VT and weft yarns HT are inclined with respect to a to-be-separated portion 58 described later. As shown in FIG. 6, the base material 56 is formed with a to-be-separated portion 58 that can be separated when the door portions 37U and 37D are opened, at a position corresponding to the to-be-broken portion 39 formed in the door arrangement portion 36 of the airbag cover 35. That is, the to-be-separated portion 58 is formed in a flattened, approximately H-shape in a state in which the base material 56 is spread out flat so as to correspond to the to-be-broken portion 39. Specifically, the section to be torn 58 includes a horizontal bar portion 58a arranged corresponding to the horizontal bar portion 39a of the section to be torn 39, and a vertical bar portion 58b arranged corresponding to the vertical bar portion 39b of the section to be torn 39. The horizontal bar portion 58a is formed at a position that is approximately aligned with the horizontal bar portion 39a of the section to be torn 39 in the front-rear direction when the section is mounted on the vehicle (see FIG. 2), and is formed in a straight line that is approximately aligned with the left-right direction so as to extend over the entire length of the horizontal bar portion 39a. The vertical bar portion 58b is formed at a position that is approximately aligned with the vertical bar portion 39b of the section to be torn 39 in the front-rear direction when the section is mounted on the vehicle (see FIG. 3), and is formed in a straight line that is approximately aligned with the up-down direction so as to extend up-down from the horizontal bar portion 58a. This vertical bar portion 58b is also formed over the entire length of the vertical bar portion 39b.

[0028] As shown in FIG. 6, the section to be divided 58 includes main slits 59 provided intermittently so as to be substantially aligned with the section to be broken 39, and sub-slits 60 arranged on at least one side of the main slits 59. In the base material 56 of the embodiment, the sub-slits 60 are arranged on both sides of the main slits 59. In the embodiment, three main slits 59 are arranged in parallel in the horizontal bar portion 58a, and two are arranged in parallel in each of the vertical bar portions 58b. The sub-slits 60 are formed at positions on both the upper and lower sides of the main slit 59 in the region of the horizontal bar portion 58a, and are formed at positions on both the left and right sides of the main slit 59 in the region of the vertical bar portion 58b. The sub-slits 60 are arranged in the base material 56 so as to cut the warp yarns VT or weft yarns HT constituting the portion of the connecting portion 62 formed between the main slits 59, 59.

[0029] Taking the main slits 59 and the sub-slits 60 formed in the region of the horizontal bar portion 58a as an example, the main slits 59 and the sub-slits 60 are both formed in the base material 56 so as to form linear cuts that are approximately along the left-right direction. The base material 56 (woven fabric) constituting the heater body 55 is configured so that the threads are aligned in the bias direction (so that the warp and weft are inclined at 45° with respect to the main slits 59 and the sub-slits 60). In the region of the main slits 59, both the warp yarns VT and the weft yarns HT are cut. As shown in FIG. 7, the sub-slits 60 are formed at four locations slightly away from the main slits 59 in the vertical direction and located inwardly and laterally from the end of the main slit 59C arranged on the central side, so as to correspond to two connecting portions 62 formed between the three main slits 59 arranged in the region of the horizontal bar portion 58a. The sub-slits 60 are formed so as to be symmetrical in the vertical and horizontal directions with respect to the center of the main slit 59C arranged on the central side. Each sub-slit 60 is disposed so as to cut the warp yarn VT or weft yarn HT constituting the connecting portion 62 formed between the main slits 59 (the region between the ends of the main slits 59 in the base material 56). Specifically, each sub-slit 60 is formed obliquely 45° above and 45° below the connecting portion 62 so as to be able to cut the warp yarn VT or weft yarn HT (inclined at 45° with respect to the main slit 59) constituting the connecting portion 62, and each sub-slit 60 has a length dimension L set to be substantially equal to the width dimension h1 of the connecting portion 62 (slightly larger than the width dimension h1 of the connecting portion 62) (see FIG. 7). The sub-slit 60U (60) located above the connecting portion 62 cuts one of the warp thread VT or weft thread HT that constitutes the connecting portion 62 (specifically, the warp thread VT), and the sub-slit 60D (60) located below the connecting portion 62 cuts the other of the warp thread VT or weft thread HT that constitutes the connecting portion 62 (specifically, the weft thread HT).That is, in the base material 56 (heater body 55) of the embodiment, in the region of the horizontal bar portion 58a constituting the section to be cut 58, both the warp threads VT and the weft threads HT are pre-cut by the main slit 59 and the sub-slits 60U, 60D over substantially the entire length of the horizontal bar portion 58a. Although detailed explanation is omitted, in the region of the two vertical bar portions 58b constituting the section to be cut 58, the sub-slits 60 are similarly configured, and in the region of these two vertical bar portions 58b, both the warp threads VT and the weft threads HT are pre-cut by the main slits 59 and the sub-slits 60. That is, in the base material 56 (heater body 55) of the embodiment, the warp threads VT and the weft threads HT constituting the base material 56 are pre-cut over substantially the entire region of the section to be cut 58.

[0030] In the heater body 55 of the embodiment, the carbon nanotubes as the heat generating means are configured to be supported on the substrate 56 by thermal transfer. Specifically, in the case of the embodiment, the carbon nanotubes are supported on the substrate 56 by printing a dispersion solution in which short fibers are dispersed in a solvent made of a cellulose-based solvent or a urethane-based solvent on a predetermined thermal transfer sheet, and then thermally transferring the dispersion solution onto the surface (the surface on the driver D side) of the substrate 56 to form the coating layer 65 (see FIG. 8). Specifically, in the embodiment, the coating layer 65 is formed on the surface of the substrate 66 using a dispersion solution containing about 5 to 6% by weight of carbon nanotubes. Note that the method of supporting the carbon nanotubes on the substrate 56 is not limited to forming the coating layer 65 by thermal transfer. For example, the carbon nanotubes dispersed in a solvent may be applied to the substrate by a suitable predetermined application method, and then dried to be supported on the substrate. In the heater body 55 of the embodiment, the to-be-cut portion 58 is formed on the substrate 56 after the carbon nanotubes are supported (after the coating layer 65 is formed). In the embodiment, carbon nanotubes are used as the heat generating means, but the heat generating means is not limited to carbon nanotubes. Examples of the heat generating means include graphene, carbon fiber (carbon), and ink containing silver particles (silver nano ink). It is preferable to use carbon nanotubes as the heat generating means by supporting them on a substrate (woven fabric), since they can be easily used and relatively inexpensively manufactured.

[0031] The coating layer 70 is disposed over the entire surface of the heater body 55 so as to cover the surface (surface 55c) facing the occupant of the heater body 55 (see FIG. 5), and is made of an insulating material. In this embodiment, the coating layer 70 is made of a urethane paint. In this embodiment, the coating layer 70 is colored black in consideration of design.

[0032] The heater H of the embodiment is attached to the rear surface (airbag cover 35 side) of the heat insulating layer 51 by providing an appropriate adhesive layer (not shown) so as to cover the rear surface (inner surface of the vehicle cabin) of the door installation portion 36 of the airbag cover 35, and is then mounted on the vehicle together with the airbag device M. When mounted on the vehicle, the electrode portion 50 of the heater H is electrically connected to a control device (not shown) via a lead wire 50a.

[0033] After the airbag device M is mounted on the vehicle, when an activation signal is input to the inflator 10 via the lead wire 12, the inflation gas is discharged from the gas discharge portion 10a of the inflator 10 and flows into the airbag 30. The door portions 37U, 37D of the airbag cover 35 are pressed by the airbag 30, which is inflated by the inflation gas flowing therein, and the door portions 37U, 37D are opened up and down around the hinge portions 42, 42 as the center of rotation while breaking the surrounding breakable portion 39. At this time, the heater body 55 of the heater H is also broken at the breakable portion 58 formed on the base material 56, and moves together with the door portions 37U, 37D. The airbag 30 then protrudes from the protrusion opening 20a of the case 20 toward the rear of the vehicle, completing the inflation as shown by the two-dot chain lines in Figs. 2 and 3 and Fig. 9.

[0034] In the heater H of the embodiment, the heater main body 55 arranged to cover the interior surface side of the airbag cover 35 (specifically, the door installation portion 36) is formed from a flexible woven fabric (base material 56), and the heater main body 55 is formed with a torn portion 58 that can be torn when the door portions 37U, 37D are opened during deployment and inflation of the airbag 30, at a position corresponding to the torn portion 39 formed in the door installation portion 36 of the airbag cover 35. The torn portion 58 is configured to include main slits 59 that are provided intermittently so as to be approximately aligned with the torn portion 39 (specifically, the horizontal bar portion 39a and the vertical bar portion 39b that constitute the torn portion 39), and sub-slits 60 that are arranged on at least one side of the main slits 59, and the sub-slits 60 are arranged so as to cut the warp yarns VT or weft yarns HT that constitute the portions of the connecting portions 62 formed between the main slits 59 in the woven fabric (base material 56). That is, in the heater H of the embodiment, in the base material 56 constituting the heater body 55, the warp yarns VT or weft yarns HT constituting the region covering the vicinity of the planned rupture portion 39 of the airbag cover 35 are previously divided by the main slits 59 and the sub-slits 60 constituting the planned rupture portion 58. Therefore, even in a configuration having the heater body 55 made of woven fabric, when the airbag 30 inflates (when the planned rupture portion 39 breaks), the heater body 55 can be quickly divided at the site of the planned rupture portion 58, and after being divided, it can be moved together with the door portions 37U, 37D that open (see FIG. 9), so that the airbag 30 can be inflated without hindrance. In the heater H of the embodiment, by providing a main slit 59 and a sub slit 60 in the woven fabric (base material 56) constituting the heater body 55, it is possible to quickly open the door portions 37U, 37D of the airbag cover 35 and the heater body 55. Therefore, there is no need to change the design of the intended rupture portion 39 provided in the airbag cover 35, and the heater H can be easily used with conventional airbag devices.

[0035] Therefore, the heater H of the embodiment can be easily used in conventional airbag devices, and increases in manufacturing costs, etc. can be suppressed.

[0036] In the heater H of the embodiment, the heater body 55 is formed by using a woven fabric as the base material 56 and carrying carbon nanotubes as heat generating means on this base material 56. Therefore, it can be manufactured relatively cheaply and easily. In particular, in the embodiment, the carbon nanotubes are carried on the base material 56 by thermal transfer, so that it is easy to manufacture. Of course, the heater body is not limited to the embodiment, and it can also be formed from a woven fabric in which carbon nanotubes as heat generating means are themselves woven.

[0037] In the heater H of the embodiment, the base material 56 constituting the heater body 55 is made of a woven fabric cut into a predetermined shape with the threads (warp threads VT and weft threads HT) aligned in the bias direction (crossing at an angle of 45°). That is, the base material 56 is arranged in a bias manner so that the warp threads VT and weft threads HT are inclined with respect to a to-be-separated portion 58 described below. Therefore, in the heater H of the embodiment, since the heater body 55 is easily stretched vertically or horizontally, it is easier to fit the heater body 55 to the surface of the airbag cover 35 and can be mounted with good design by minimizing the generation of wrinkles, etc., compared to a case where a base material is used that is cut with the warp threads VT aligned approximately vertically. Furthermore, in the heater H of the embodiment, the sub-slits 60 in the section to be cut 58 are arranged on both sides of the main slit 59, and one of them is configured to cut one of the warp threads VT or weft threads HT constituting the connecting portion 62, and the other is configured to cut the other of the warp threads VT or weft threads HT constituting the connecting portion 62. That is, in the heater H of the embodiment, the main slit 59 and the sub-slits 60 are configured to cut both the warp threads VT and weft threads HT in advance, and the warp threads VT and weft threads HT constituting the base material 56 are cut in advance over substantially the entire area of ​​the section to be cut 58. Therefore, even in the configuration using the base material 56 cut in the bias direction, the heater main body 55 can be quickly and stably cut at the section to be cut 58 when the airbag 30 is inflated (when the section to be cut 39 is broken). Furthermore, even if the warp threads VT and weft threads HT constituting the base material 56 are cut in advance over substantially the entire area of ​​the intended separation portion 58, the warp threads VT and weft threads HT are cut by the main slit 59 and the sub-slits 60 arranged to the sides of the main slit 59, so that such cut areas are not noticeable when the product is mounted on a vehicle, and the design when mounted on a vehicle is also good.

[0038] If the above points are not taken into consideration, a base material 56A cut so that the warp threads VT run in the vertical direction and the weft threads HT run in the horizontal direction, as shown in FIG. 10, may be used. When using such a base material 56A, the sub-slit 60A may be disposed only on one side of the main slit 59A (only the upper side in FIG. 10) so as to cut one of the warp threads VT that constitute the connecting portion 62A.

[0039] In the embodiment, a knee protection airbag device disposed in front of the driver's seat is taken as an example of an airbag device using the heater H, but the airbag device in which the heater of the present invention can be mounted is not limited to the embodiment. Of course, the heater of the present invention can also be used in a knee protection airbag device disposed in front of the passenger seat, and can also be used in, for example, an airbag device for a steering wheel mounted on a steering wheel. When used in an airbag device for a steering wheel, the heater is disposed so as to cover the front side of an airbag cover (pad) on the steering wheel. [Explanation of symbols]

[0040] 8...steering column, 10...inflator, 20...case, 30...airbag, 35...airbag cover, 36...door mounting section, 37U, 37D...door section, 39...proposed rupture section, 55...heater body, 56...base material, 58...proposed separation section, 59...main slit, 60...sub slit, 62...connection section, VT...warp thread, HT...weft thread, D...driver (occupant), M...knee protection airbag device (airbag device), H...heater.

Claims

1. an airbag that is folded and stored in a storage area; an airbag cover that is disposed to cover the airbag and has a door portion that can be opened by breaking a breakable portion disposed on a periphery of the airbag when the airbag is deployed and inflated; The present invention is used in an airbag device having A heater for an airbag device, the heater being disposed so as to cover a surface side of the airbag cover in a vehicle interior and capable of radiating radiant heat to an occupant in the vehicle interior, The airbag cover is configured to cover a surface side of the airbag cover in the passenger compartment, and the airbag cover is configured to include a sheet-shaped heater body that generates heat and emits radiant heat. the heater body is formed of a flexible woven fabric, has a heat generating means, and is configured to have a breakable portion that can be broken when the door portion is opened, at a position corresponding to the breakable portion formed on the airbag cover; The intended breaking portion includes a main slit that is intermittently provided so as to substantially follow the intended breaking portion, and a sub-slit that is disposed on at least one side of the main slit, The heater for an airbag device, wherein the sub-slit is arranged so as to cut warp or weft threads constituting a connecting portion formed between the main slits in the woven fabric.

2. 2. The heater for an airbag device according to claim 1, wherein the heater body is constructed by using the woven fabric as a base material and supporting carbon nanotubes as the heat generating means on the base material.

3. 2. The heater for an airbag device according to claim 1, wherein the heater body is made of a woven fabric formed by weaving carbon nanotubes as the heat generating means.

4. 4. The heater for an airbag device according to claim 1, wherein the woven fabric is arranged in a bias manner such that the warp threads and the weft threads are inclined with respect to the intended separation portion.

5. The heater for an airbag device according to claim 4, characterized in that the sub-slits are arranged on both sides of the main slit, one of which cuts one of the warp threads or the weft threads that constitute the connecting portion, and the other of which cuts the other of the warp threads or the weft threads that constitute the connecting portion.

6. An airbag device comprising: an airbag; a storage portion for storing the airbag in a folded state; an airbag cover for covering the folded airbag; and a heater disposed to cover an interior surface side of the airbag cover, The heater is configured to include a sheet-shaped heater main body that is arranged to cover the interior surface side of the airbag cover and is capable of generating heat and radiating radiant heat, The airbag cover is configured to include a door portion that can be opened by breaking a breakable portion that is arranged on a periphery of the airbag when the airbag is deployed and inflated, the heater body is formed of a flexible woven fabric, has a heat generating means, and is configured to have a breakable portion at a position corresponding to the breakable portion formed in the airbag cover, the breakable portion being breakable when the door portion is opened; The intended breaking portion includes a main slit that is intermittently provided so as to substantially follow the intended breaking portion, and a sub-slit that is disposed on at least one side of the main slit, The airbag device is characterized in that the sub-slits are arranged in such a manner as to cut warp or weft threads constituting a connecting portion formed between the main slits in the woven fabric.

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