Airbag system heater
A flexible woven fabric heater with slits allows seamless integration into conventional airbag systems, facilitating easy deployment and heat radiation without design changes or cost increases.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYODA GOSEI CO LTD
- Filing Date
- 2023-09-27
- Publication Date
- 2026-06-18
Smart Images
Figure 0007875469000001 
Figure 0007875469000002 
Figure 0007875469000003
Abstract
Description
Technical Field
[0001] The present invention relates to a heater for an airbag device that is disposed so as to cover the vehicle interior surface side of an airbag cover in the airbag device and can radiate radiant heat to an occupant in the vehicle interior.
Background Art
[0002] Conventionally, as a heater for an airbag device, there has been a configuration including an interior panel corresponding to an airbag cover in the airbag device, a heater body disposed on the vehicle interior surface side of the interior panel, and an outer skin layer covering the heater body (see, for example, Patent Document 1). In this conventional heater for an airbag device, the outer skin layer covering the heater body was made of a woven fabric or a knitted fabric. And, in order to smoothly break the outer skin layer when the interior panel is opened, the outer shape of the tear portion (planned break portion) provided in the interior panel as viewed from the vehicle interior surface side of the interior panel is formed in a zigzag shape or a shape in which concavities and convexities are alternately connected, so that stress is locally concentrated on the outer skin layer at the time of breakage of the tear portion to break the outer skin layer.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, in the conventional heater for an airbag device, by changing the shape of the tear portion of the interior panel (a member corresponding to the airbag cover in a normal airbag device), the member (outer skin layer) on the heater side at the time of inflation of the airbag was set to be easily opened. Therefore, for example, it was not possible to easily mount the conventional airbag device, and it was necessary to change the design of the airbag device itself (specifically, the airbag cover).
[0005] The present invention aims to solve the above-mentioned problems and provide an airbag heater that can be easily used with conventional airbag devices and can suppress increases in manufacturing costs, etc. [Means for solving the problem]
[0006] The heater for an airbag device according to the present invention includes an airbag that is folded and stored in a storage area, An airbag cover having a door portion that is positioned to cover the airbag and can be opened by rupturing a portion designated to rupture at its periphery when the airbag deploys and inflates, Used in airbag systems equipped with, A heater for an airbag system, which is positioned to cover the interior surface of the airbag cover and capable of radiating heat to the occupants inside the vehicle, The system is configured to include a sheet-like heater body positioned to cover the interior surface of the airbag cover, which is capable of generating heat and radiating heat. The heater body is formed from a flexible woven fabric and has a heating element, and is configured to have a section that is designed to be separated when the door is opened, at a position corresponding to the section that is designed to be separated when the door is opened, which is formed in the airbag cover. The section to be divided comprises a main slit provided intermittently along the section to be broken, and a sub-slit positioned to at least one side of the main slit. The sub-slits are arranged in such a way that they cut the warp or weft threads that constitute the connecting portion formed between the main slits in the woven fabric.
[0007] In the heater for the airbag device of the present invention, the heater body, which is arranged to cover the interior surface side of the airbag cover, is made of a flexible woven fabric. The heater body has a section that is designed to be separated when the door opens during the deployment and inflation of the airbag, at a position corresponding to the section that is designed to be separated in the airbag cover. The section that is designed to be separated comprises a main slit that is provided intermittently along the section that is designed to be separated, and a sub-slit that is arranged to at least one side of the main slit. The sub-slit is arranged in such a way that it cuts the warp or weft threads that constitute the connecting portion formed between the main slits in the woven fabric. In other words, in the heater for the airbag device of the present invention, the warp or weft threads that constitute the region covering the area near the section that is designed to be separated in the heater body are separated in advance by the main slits and sub-slits that constitute the section that is designed to be separated. Therefore, even with a heater body made of woven fabric, when the airbag inflates (when the intended rupture point ruptures), the heater body can be quickly separated at the intended rupture point, and after separation, it can be moved together with the opening door, allowing the airbag to inflate without hindrance. Furthermore, in the heater for airbag devices of the present invention, by providing a main slit and a sub-slit in the woven fabric constituting the heater body, the door of the airbag cover and the heater body can be quickly opened, eliminating the need to change the design of the intended rupture point on the airbag cover, and allowing it to be easily used in conventional airbag devices.
[0008] Therefore, the heater for airbag systems of the present invention can be easily used in conventional airbag systems, and increases in manufacturing costs and other factors 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 means of generating heat, or a woven fabric formed by weaving carbon nanotubes themselves.
[0010] Furthermore, the woven fabric constituting the heater body can be arranged in a bias configuration, such that the warp and weft threads are inclined relative to the intended rupture point of the airbag cover.
[0011] When the woven fabric constituting the heater body is arranged in a bias shape, it is preferable to place sub-slits on both sides of the main slit, with one sub-slit cutting one of the warp or weft threads constituting the connecting part, and the other sub-slit cutting the other of the warp or weft threads constituting the connecting part. [Brief explanation of the drawing]
[0012] [Figure 1] This is a schematic longitudinal cross-sectional view in the front-rear direction of a vehicle showing the usage state of a knee protection airbag device using a heater, which is one embodiment of the present invention. [Figure 2] Figure 1 is a schematic enlarged longitudinal cross-sectional view of the knee protection airbag device in the vehicle's longitudinal direction. [Figure 3] Figure 1 is a schematic cross-sectional view of the knee protection airbag system in the vehicle's left-right direction. [Figure 4] Figure 1 is a schematic front view from the rear of the vehicle, showing the knee protection airbag system in use. [Figure 5] This is a schematic cross-sectional view of the heater according to the embodiment. [Figure 6] This is a schematic rear view (viewed from the back side) showing the heater body and electrode section in the heater of the embodiment. [Figure 7] This is a partially enlarged plan view showing the portion of the base material in the heater body of the embodiment that is intended to be divided. [Figure 8] This is a partially enlarged schematic cross-sectional view of the heater body of the embodiment. [Figure 9] Figure 1 is a schematic enlarged longitudinal cross-sectional view in the vehicle's longitudinal direction, showing the knee protection airbag device with the airbag fully inflated. [Figure 10] This is a partially enlarged plan view of the substrate constituting the heater body, which is another embodiment. [Modes for carrying out the invention]
[0013] Hereinafter, an embodiment of the present invention will be described based on the drawings. In the embodiment, as an example, a heater H for an airbag device (hereinafter simply referred to as "heater") used in a knee protection airbag device (hereinafter simply referred to as "airbag device") M will be described. As shown in FIG. 1, the airbag device M is disposed in a region below the steering column 8 on the front side of the vehicle of the driver D so as to be able to protect the knees K (KL, KR) of the occupant (driver D) seated on the seat (in the case of the embodiment, the driver's seat). In the embodiment, the up-down, left-right, and front-back directions are the same as the up-down, left-right, and front-back directions of the vehicle when the airbag device M is mounted on the vehicle, unless otherwise specified.
[0014] As shown in FIGS. 2 and 3, the airbag device M includes a folded airbag 30, an inflater 10 that supplies inflation gas to the airbag 30, a case 20 as a storage part for storing the folded airbag 30 and the inflater 10, a retainer 15 for holding the inflater 10 and attaching the inflater 10 and the airbag 30 to the case 20, an airbag cover 35 that covers the folded airbag 30, and a heater H disposed so as to cover the vehicle interior surface side (rear surface side) of the airbag cover 35.
[0015] As shown in FIGS. 2 and 3, the inflater 10 has a substantially cylindrical shape with its axial direction substantially along the left-right direction. In the case of the embodiment, a gas discharge part 10a having a number of gas discharge ports (reference numerals omitted) capable of discharging inflation gas is disposed on the left end side. A connector 11 to which a lead wire 12 for inputting an operation signal extending from a control device (not shown) is connected is connected to the right end side of the inflater 10.
[0016] As shown in FIGS. 2 and 3, the retainer 15 that holds the inflator 10 includes a substantially cylindrical holding portion 16 that covers the outer peripheral side of the inflator 10, and two bolts 17, 17 that project so as to be substantially orthogonal to the axial direction of the holding portion 16. In the airbag device M of the embodiment, the inflator 10 is housed in the holding portion 16 of the retainer 15 disposed in the airbag 30. When the airbag 30 is housed in the case, the bolts 17 of the retainer 15 are projected from the bottom wall portion 21 of the case 20, and the inflator 10 and the airbag 30 are attached to the case 20 by fastening a nut 18 to the bolts 17.
[0017] The case 20 as the housing portion is made of sheet metal. As shown in FIGS. 2 and 3, it has a substantially rectangular tube-shaped bottom wall portion 21 disposed on the front side of the vehicle, and a substantially rectangular tube-shaped peripheral wall portion 22 extending rearward from the periphery of the bottom wall portion 21. The rear end side of the peripheral wall portion 22 has a substantially box shape with a projecting opening 20a through which the airbag 30 can project. In the case of the embodiment, the case 20 is formed wide in the left-right direction. In the peripheral wall portion 22, locking claw portions 22c for locking the attachment piece portions 44U and 44D of the airbag cover 35, which will be described later, are provided on the rear end sides of the upper side wall 22a and the lower side wall 22b that face each other vertically. Although detailed illustration is omitted, a plurality of the locking claw portions 22c are formed along the left-right direction. Also, although detailed illustration is omitted, attachment brackets 24 and 25 for attaching the case 20 to the body 1 side are disposed on both the left and right end sides of the upper side wall 22a and the lower side wall 22b in the case 20, as shown in FIG. 4. The attachment bracket 24 provided on the upper side wall 22a side is connected to brackets 4 and 4 extending from the instrument panel reinforcement on the body 1 side, as shown in FIG. 4. The attachment bracket 25 provided on the lower side wall 22b side is connected to brackets 5 and 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 a bag-shaped structure made from a flexible woven fabric consisting of polyamide yarn, polyester yarn, etc. When fully inflated, it takes the shape of a roughly rectangular plate as shown by the dashed lines in Figures 1 and 4, and is configured to protect the left and right knees K (KL, KR) of the driver D.
[0019] The airbag cover 35 is positioned to cover the rear side of the airbag 30, which is folded and stored inside the case 20. Specifically, it is configured to cover the rear side of the case 20. The airbag cover 35 is made of a thermoplastic elastomer such as a polyolefin. In this embodiment, as shown in Figure 4, it is positioned below the steering column 8 when viewed from the rear of the vehicle, and is located on the lower panel 9b side of the instrument panel (hereinafter abbreviated as "instrument panel") 9, which is composed of an upper panel 9a and a lower panel 9b. Also, as shown in Figure 1, the airbag cover 35 is positioned in front of the knees K of the driver D seated in the driver's seat. In this embodiment, the airbag cover 35 includes a door mounting portion 36 located near the protruding opening 20a of the case 20, and a peripheral edge portion 47 extending around the door mounting portion 36.
[0020] The door mounting section 36 comprises two door sections 37U and 37D arranged side by side, one above the other, to cover the protruding opening 20a of the case 20; a breakable section 39 and a hinge section 42 arranged around the door sections 37U and 37D; and mounting pieces 44U and 44D extending forward from the upper end of the upper door section 37U and the lower end of the lower door section 37D, respectively. The two door sections 37U and 37D cover the rear side of the protruding opening 20a of the vehicle and are configured to open to both the upper and lower sides when opened. The breakable section 39 arranged around the door sections 37U and 37D is roughly H-shaped when viewed from the rear side of the vehicle (see Figure 4). The planned rupture section 39 is formed by recessing the door mounting section 36 from the back side (vehicle front side). In this embodiment, as shown in Figures 2 and 3, the door mounting section 36 is recessed in a roughly V-shape in cross-section. The planned rupture section 39 is constructed by continuously arranging such recesses along its entire length. To describe the planned rupture section 39 in detail, it comprises a horizontal bar section 39a arranged in a roughly straight line along the left-right direction between the door sections 37U and 37D, and two vertical bar sections 39b, 39b arranged on the left and right sides of the upper and lower door sections 37U and 37D, extending vertically from the horizontal bar section 39a. Each vertical bar section 39b is roughly straight along the vertical direction, roughly perpendicular to the horizontal bar section 39a (see Figure 4). As shown in Figure 2, the hinge portion 42 is located at the upper end of the upper door portion 37U and at the lower end of the lower door portion 37D. Each door portion 37U and 37D opens using this hinge portion 42 as the center of rotation when opened. The mounting pieces 44U and 44D are located adjacent to each other on the outer circumference of the upper wall 22a and lower wall 22b of the case 20, respectively, and are positioned to protrude toward the front of the vehicle. They are equipped with a locking hole 44a for engaging the locking claw portion 22c formed in the case 20.
[0021] The peripheral edge 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 on the vehicle than the door portions 37U and 37D. It supports the portions of the lower panel 9b that are located on both the left and right sides of the door portions 37U and 37D, so that the rearward surfaces of the door portions 37U and 37D and the lower panel 9b are substantially flush with each other (see Figure 3).
[0022] The heater H, which is positioned to cover the interior surface (rear side) of the airbag cover 35, is capable of radiating heat to the occupants inside the vehicle (in this embodiment, the driver D seated in the driver's seat) when activated. In this embodiment, as shown in Figures 2 and 3, the heater H is positioned to cover almost the entire rear side of the door mounting portion 36 of the airbag cover 35. The heater H is made of a flexible sheet, and in this embodiment, its overall thickness is set to approximately 20 μm to 2 mm.
[0023] As shown in the schematic cross-section of Figure 5, the heater H comprises a heater body 55 formed in a sheet shape, an electrode portion 50 arranged around the heater body 55, a heat insulating layer 51 arranged on the front side (airbag cover 35 side) when mounted in the vehicle, and a coating layer 70 arranged on the rear side (driver D side) when mounted in 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 between them. In this embodiment, the external shape of the heater H is made to be substantially the same as the external 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. In detail, it is a substantially rectangular plate shape that is wide on the left and right sides.
[0024] In this embodiment, the electrode portion 50 is made of a strip-shaped metal foil (specifically, copper foil in this embodiment). In this embodiment, the electrode portion 50 is continuously arranged over substantially the entire area on both the left and right sides of the heater H (heater body 55), from the upper end to the lower end (see Figure 6). In this embodiment, as shown in Figure 5, the electrode portion 50 is arranged so as to overlap the airbag cover 35 side surface (back surface 55d side) on the upper edge 55a side and the lower edge 55b side of the heater body 55. In Figure 5, a step difference equal to the thickness of the electrode portion 50 is depicted, but in reality, the electrode portion 50 is thin and such a step difference hardly occurs. Each electrode portion 50 is positioned above or below the door portions 37U and 37D when mounted in the vehicle (in a position that does not overlap with the planned break portion 39). Each electrode section 50 is electrically connected to a control device (not shown) via a lead wire 50a (see Figure 6) that extends from one end. When current is applied, the electrode section 50 generates heat itself, and at the same time, the carbon nanotubes, which will be described later and are provided in the heater body 55 as a heating means, also generate heat.
[0025] The heat-insulating layer 51 is designed to efficiently radiate heat to the driver D side by reflecting the heat generated when the electrode section 50 is energized, while suppressing its propagation to the airbag cover 35 side. In this embodiment, although detailed illustrations are omitted, the heat-insulating layer 51 is formed from a nonwoven fabric with aluminum foil (metal foil) deposited on one side, and is positioned so that the aluminum foil is on the heater body 55 side. As shown in Figure 5, this heat-insulating layer 51 is arranged to cover almost the entire front side (airbag cover 35 side) of the heater body 55 and the electrode section 50. The material used to form the heat-insulating layer 51 is not limited to this embodiment. As the heat-insulating layer, materials such as glass fiber, silica fiber, fluorocarbon fiber, BASHFIBER®, or urethane foam can be used as a base material, with metal foil deposited on it.
[0026] The heater body 55 has a heating element and is formed from a flexible woven fabric. In this embodiment, the heater body 55 is constructed by using a woven fabric as a base material 56 and supporting carbon nanotubes as a heating element on this base material 56. The external shape of the heater body 55 is substantially the same as the external shape of the heater H, that is, substantially the same as the external 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 the entire rear side of the door mounting portion 36. In other words, the external shape of the heater body 55 (base material 56) is substantially rectangular with a wide width from left to right, as shown in Figure 6.
[0027] In this embodiment, the base material 56 is a woven fabric made by plain weaving yarns consisting of polyamide yarn or polyester yarn. More specifically, as shown in Figure 7, the base material 56 is made by cutting the woven fabric into a predetermined shape with the threads (warp VT and weft HT) aligned in the bias direction (intersecting at a 45° angle). That is, the base material 56 is arranged bias-wise so that the warp VT and weft HT are inclined with respect to the division section 58, which will be described later. As shown in Figure 6, the base material 56 has a division section 58 that can be divided when the door sections 37U and 37D are opened, at a position corresponding to the division section 39 formed in the door arrangement section 36 of the airbag cover 35. That is, the division section 58 is formed in a flat, approximately H-shape when the base material 56 is laid flat, so as to correspond to the division section 39. Specifically, the planned separation section 58 comprises a horizontal bar section 58a positioned to correspond to the horizontal bar section 39a of the planned fracture section 39, and a vertical bar section 58b positioned to correspond to the vertical bar section 39b of the planned fracture section 39. The horizontal bar section 58a is formed at a position that substantially coincides with the horizontal bar section 39a of the planned fracture section 39 in the front-to-back direction when mounted on a vehicle (see Figure 2), and is formed in a straight line that substantially follows the left-to-right direction, extending along the entire length of the horizontal bar section 39a. The vertical bar section 58b is formed at a position that substantially coincides with the vertical bar section 39b of the planned fracture section 39 in the front-to-back direction when mounted on a vehicle (see Figure 3), and is formed in a straight line that substantially follows the up-to-down direction, extending vertically from the horizontal bar section 58a. This vertical bar section 58b is also formed along the entire length of the vertical bar section 39b.
[0028] Furthermore, as shown in Figure 6, the planned division section 58 includes main slits 59 provided intermittently along the planned break section 39, and sub-slits 60 arranged to at least one side of the main slits 59. In the base material 56 of this embodiment, the sub-slits 60 are arranged on both sides of the main slits 59. In this embodiment, three main slits 59 are arranged side by side in the horizontal bar section 58a, and two main slits 59 are arranged side by side in each vertical bar section 58b. In the region of the horizontal bar section 58a, the sub-slits 60 are formed on both the upper and lower sides of the main slits 59, and in the region of the vertical bar section 58b, they are formed on both the left and right sides of the main slits 59. These sub-slits 60 are arranged in the base material 56 in such a way that they cut the warp threads VT or weft threads HT that constitute the connecting section 62 formed between the main slits 59, 59.
[0029] Taking the main slit 59 and sub-slit 60 formed in the region of the horizontal bar 58a as an example, to explain in detail, both the main slit 59 and sub-slit 60 are formed in the base material 56 by creating a straight cut that is roughly aligned in the left-right direction. The base material 56 (woven fabric) that constitutes the heater body 55 is configured so that the threads are aligned in the bias direction (the warp and weft threads are inclined at 45° with respect to the main slit 59 and sub-slit 60). In the region of the main slit 59, both the warp thread VT and the weft thread HT are cut. As shown in Figure 7, the sub-slits 60 are formed at four locations slightly above and below the main slits 59, and inward to the left and right of the end of the main slit 59C located on the central side, so as to correspond to the two connecting parts 62 formed between the three main slits 59 arranged in the region of the horizontal bar 58a. These sub-slits 60 are formed so as to be symmetrical in all directions, up, down, left, and right, with respect to the center of the main slit 59C located on the central side. Each sub-slit 60 is positioned to cut the warp threads VT or weft threads HT that constitute the connecting portion 62 formed between the main slits 59, 59 (the region between the ends of the main slits 59, 59 in the base material 56). Specifically, each sub-slit 60 is formed at an angle of 45° above and 45° below the connecting portion 62 so as to be able to cut the warp threads VT or weft threads HT (which are inclined at 45° with respect to the main slits 59) that constitute the connecting portion 62, and the length dimension L of each is set to be approximately the same as the width dimension h1 of the connecting portion 62 (slightly larger than the width dimension h1 of the connecting portion 62) (see Figure 7). Furthermore, the sub-slit 60U(60) positioned above the connecting portion 62 cuts one of the warp threads VT or weft threads HT (specifically, the warp threads VT) that constitute the portion of the connecting portion 62, and the sub-slit 60D(60) positioned below the connecting portion 62 cuts the other of the warp threads VT or weft threads HT (specifically, the weft threads HT) that constitute the portion of the connecting portion 62.In other words, in the base material 56 (heater body 55) of the embodiment, the area of the horizontal bar portion 58a constituting the section to be divided 58 has the warp threads VT and weft threads HT pre-cut over substantially the entire length of the horizontal bar portion 58a by the main slit 59 and sub-slits 60U, 60D. Although a detailed explanation is omitted, the sub-slits 60 are similarly configured in the areas of the two vertical bar portions 58b constituting the section to be divided 58, and in these areas of the two vertical bar portions 58b as well, the warp threads VT and weft threads HT are pre-cut over substantially the entire length of the section to be divided 58.
[0030] In the heater body 55 of this embodiment, the carbon nanotubes, which serve as the heat-generating means, are supported on the substrate 56 by thermal transfer. Specifically, in this embodiment, the carbon nanotubes are supported on the substrate 56 by thermal transfer of a dispersion solution, in which short fibers of carbon nanotubes are dispersed in a solvent consisting of a cellulose-based solvent or a urethane-based solvent, onto a predetermined thermal transfer sheet, and then onto the surface of the substrate 56 (the side facing the driver D) (see Figure 8). Specifically, in this embodiment, a dispersion solution containing approximately 5-6% by weight of carbon nanotubes is used to form the coating layer 65 on the surface of the substrate 66. Note that the method of supporting the carbon nanotubes on the substrate 56 is not limited to the formation of the coating layer 65 by thermal transfer. For example, carbon nanotubes dispersed in a solvent may be applied to the substrate using a predetermined coating method as appropriate, and then dried to support them on the substrate. In the heater body 55 of this embodiment, the division portion 58 is formed on the substrate 56 after the carbon nanotubes are supported (after the formation of the coating layer 65). In this embodiment, carbon nanotubes are used as the heat-generating means, but the heat-generating means is not limited to carbon nanotubes. Examples of heat-generating means include graphene, carbon fibers (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) because they are easy to support and relatively inexpensive to manufacture.
[0031] The coating layer 70 is provided across the entire surface of the heater body 55 so as to cover the occupant-side surface (surface 55c) of the heater body 55 (see Figure 5), and is made of an insulating material. In this embodiment, the coating layer 70 is made of a urethane-based paint. Also, in this embodiment, the coating layer 70 is colored black for aesthetic reasons.
[0032] In this embodiment, the heater H is attached to the rear side (interior surface) of the door mounting portion 36 of the airbag cover 35 by providing an appropriate adhesive layer (not shown) on the back surface (airbag cover 35 side) of the heat insulation layer 51, and is mounted in the vehicle together with the airbag device M. When mounted in 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 installed in the vehicle, an activation signal is input to the inflator 10 via the lead wire 12, and inflation gas is discharged from the gas discharge port 10a of the inflator 10 and flows into the airbag 30. The door portions 37U and 37D of the airbag cover 35 are pressed by the airbag 30, which is inflating as the inflation gas flows into it, and the door portions 37U and 37D of the airbag cover 35 open up and down around the hinge portions 42 and 42 as the pivot point, while rupturing the surrounding pre-rupture portions 39. At this time, the heater body 55 of the heater H is also divided at the pre-rupture portion 58 formed on the base material 56 and moves together with the door portions 37U and 37D. The airbag 30 then protrudes from the protruding opening 20a of the case 20 toward the rear of the vehicle and completes inflation as shown by the dashed lines in Figures 2 and 3 and in Figure 9.
[0034] In the heater H of this embodiment, the heater body 55, which is arranged to cover the interior surface side of the airbag cover 35 (specifically the door mounting portion 36), is made of a flexible woven fabric (base material 56). The heater body 55 has a section 58 that is designed to be separated when the door portions 37U and 37D open during the deployment and inflation of the airbag 30, at a position corresponding to the section 39 that is designed to be separated when the door portions 37U and 37D open. The section 58 is configured to include a main slit 59 that is provided intermittently along the section 39 (more specifically, the horizontal bar portion 39a and vertical bar portion 39b that constitute the section 39), and a sub-slit 60 that is arranged to at least one side of the main slit 59. The sub-slit 60 is arranged in the woven fabric (base material 56) in such a way that it cuts the warp threads VT or weft threads HT that constitute the connecting portion 62 formed between the main slits 59. In other words, in the heater H of the embodiment, the warp threads VT or weft threads HT that constitute the area covering the vicinity of the planned rupture portion 39 of the airbag cover 35 in the base material 56 constituting the heater body 55 are pre-divided by the main slit 59 and sub-slit 60 that constitute the planned division portion 58. Therefore, even with a heater body 55 made of woven fabric, when the airbag 30 inflates (when the planned rupture portion 39 ruptures), the heater body 55 can be quickly divided at the planned division portion 58, and after division, it can be moved together with the opening door portions 37U and 37D (see Figure 9), so that the airbag 30 can be inflated without any problems. Furthermore, in the heater H of this embodiment, a main slit 59 and a sub-slit 60 are provided in the woven fabric (base material 56) that constitutes the heater body 55, enabling rapid opening of the door portions 37U and 37D of the airbag cover 35 and the heater body 55. Therefore, it is not necessary to change the design of the planned rupture portion 39 provided in the airbag cover 35, and it can be easily used in conventional airbag devices.
[0035] Therefore, the heater H of this embodiment can be easily used in conventional airbag devices, and increases in manufacturing costs and other factors can be suppressed.
[0036] In the heater H of this embodiment, the heater body 55 is constructed by using a woven fabric as a base material 56 and supporting carbon nanotubes, which serve as a heat-generating means, on this base material 56. Therefore, it can be manufactured relatively inexpensively and easily. In particular, in this embodiment, since the carbon nanotubes are supported on the base material 56 by thermal transfer, manufacturing is easy. Of course, the heater body is not limited to this embodiment, and can also be formed from a woven fabric in which the carbon nanotubes themselves, which serve as a heat-generating means, are woven.
[0037] Furthermore, in the heater H of this embodiment, the base material 56 constituting the heater body 55 is made by cutting a woven fabric into a predetermined shape with the threads (warp threads VT and weft threads HT) aligned in the bias direction (intersecting at a 45° angle). That is, the base material 56 is arranged in a bias shape with respect to the division section 58, which will be described later, with respect to the warp threads VT and weft threads HT. Therefore, in the heater H of this embodiment, the heater body 55 is easy to stretch vertically or horizontally, and compared to the case where the base material is made by cutting with the warp threads VT aligned in the vertical direction, it is easier to conform to the surface of the airbag cover 35, minimizing the occurrence of wrinkles and allowing for installation with good design. Furthermore, in the heater H of this embodiment, the sub-slits 60 in the section to be divided 58 are positioned 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 that constitute the connecting section 62, while the other is configured to cut the other of the warp threads VT or weft threads HT that constitute the connecting section 62. In other words, in the heater H of this embodiment, the warp threads VT and weft threads HT are both pre-cut by the main slit 59 and the sub-slits 60, and the warp threads VT and weft threads HT that constitute the base material 56 are pre-cut over substantially the entire area of the section to be divided 58. Therefore, even if a base material 56 cut in the bias direction is used, the heater body 55 can be quickly and stably divided at the section to be divided 58 when the airbag 30 inflates (when the section to be ruptured 39 ruptures). Furthermore, even if the warp threads VT and weft threads HT constituting the base material 56 are pre-cut over almost the entire area of the section to be divided 58, the warp threads VT and weft threads HT are cut by the main slit 59 and the sub-slit 60 located to the side of the main slit 59. As a result, when mounted on a vehicle, these cut sections are not conspicuous, and the design is also good when mounted on a vehicle.
[0038] If the above points are not taken into consideration, as shown in Figure 10, a base material 56A may be used that has been cut so that the warp threads VT are aligned vertically and the weft threads HT are aligned horizontally. When using such a base material 56A, the sub-slit 60A should be placed only on one side of the main slit 59A (only the top side in Figure 10) so as to cut one of the warp threads VT that constitute the connecting portion 62A.
[0039] In the embodiments, a knee protection airbag system located in front of the driver's seat is used as an example of an airbag system using heater H, but the airbag system on which the heater of the present invention can be installed is not limited to these embodiments. Of course, the heater of the present invention can also be used in a knee protection airbag system located in front of the passenger seat, and can also be used, for example, in a steering wheel airbag system mounted on the steering wheel. When used in a steering wheel airbag system, the heater will be arranged to cover the surface side of the 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...Section intended to break, 55...Heater body, 56...Base material, 58...Section intended to break, 59...Main slit, 60...Sub-slit, 62...Connecting section, VT...Warp thread, HT...Weft thread, D...Driver (occupant), M...Knee protection airbag device (airbag device), H...Heater.
Claims
1. The airbag folds up and is stored in the storage compartment, An airbag cover having a door portion that is positioned to cover the airbag and can be opened by rupturing a portion designated to rupture on its periphery when the airbag is deployed and inflated, Used in airbag systems equipped with, A heater for an airbag system, which is disposed to cover the interior surface side of the airbag cover and capable of radiating heat to the occupants in the interior of the vehicle, The configuration includes a sheet-like heater body positioned to cover the interior surface side of the airbag cover, which is capable of generating heat and radiating heat. The heater body is formed from a flexible woven fabric and has a heating means, and is configured to have a planned separation portion that can be separated when the door is opened, at a position corresponding to the planned rupture portion formed in the airbag cover. The portion to be divided comprises a main slit provided intermittently along the portion to be broken, and a sub-slit positioned to at least one side of the main slit. A heater for an airbag device, characterized in that the sub-slits are arranged in such a way as to cut the warp or weft threads that constitute the connecting portion formed between the main slits in the woven fabric.
2. The heater for an airbag device according to claim 1, characterized in that the heater body is constructed using the woven fabric as a base material, with carbon nanotubes as the heat-generating means supported on the base material.
3. The heater for an airbag device according to claim 1, characterized in that the heater body is made of a woven fabric formed by weaving together carbon nanotubes as the heat-generating means.
4. The heater for an airbag device according to any one of claims 1 to 3, characterized in that the woven fabric is arranged in a bias shape such that the warp threads and weft threads are inclined with respect to the portion to be divided.
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, and one of them is configured to cut one of the warp threads or weft threads constituting the connecting portion, and the other is configured to cut the other of the warp threads or weft threads constituting the connecting portion.
6. An airbag system comprising an airbag, a storage compartment for folding and storing the airbag, an airbag cover that covers the folded airbag, and a heater disposed to cover the interior surface side of the airbag cover, The heater is configured to include a sheet-like heater body that is positioned 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 rupturing a portion designated to rupture on its periphery when the airbag is deployed and inflated. The heater body is formed from a flexible woven fabric and has a heating means, and is configured to have a planned separation portion that can be separated when the door is opened, at a position corresponding to the planned rupture portion formed in the airbag cover. The portion to be divided comprises a main slit provided intermittently along the portion to be broken, and a sub-slit positioned to at least one side of the main slit. An airbag device characterized in that the sub-slits are arranged in the woven fabric in such a way as to cut the warp or weft threads that constitute the connecting portion formed between the main slits.