JPH06298030A - Storage pad for airbag and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a storage pad for airbag which is provided with a horn switch operated by pressing operation and which can prevent unintentional cleavage of the storage pad formed at the storage pad. CONSTITUTION:This storage pad 1 is provided with a top panel 3 of single layer structure or double layer structure made of an elastic material, a tialine 8 which induces or promotes cleavage of the top panel when an airbag is developed, and a mounting part 5 for mounting the storage pad to the body of an airbag device. At an area of the top panel 3 located outside lid parts 3a, 3b which rotate when the airbag is developed and a rotating shaft line 19 of lid parts 3a, 3b, a horn switch 10 is embedded along a mounting part 5. At an area of the top panel 3 equipped with the horn switch 10, reinforcing rib 9 which improved stiffness of the area is disposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage pad for an air bag and a method for manufacturing the storage pad. More specifically, the present invention relates to a top surface portion having a one-layer structure or a two-layer structure made of an elastic material. A storage pad for an airbag including a tear line that induces or promotes tearing of the top surface portion when the airbag is deployed, and a mounting portion for mounting the storage pad on the main body of the airbag device, and a method for manufacturing the storage pad. It is about.

[0002]

2. Description of the Related Art An air bag device provided in a central region of a steering wheel of a vehicle has been widely put into practical use. The airbag device is deployed between the driver and the steering wheel to protect the driver when the vehicle is subjected to an unexpected shock or sudden acceleration / deceleration, and reduces the shock that may be applied to the driver. .

Such an airbag device generally comprises a gas generator (inflator) for inflating the airbag,
An airbag stored in the device in a folded state,
And a storage pad defining an airbag storage chamber. The storage pad is generally made of a resin molded product and faces the passenger compartment and expands when the airbag is inflated (hereinafter,
A so-called tear line that induces or promotes tearing of the top surface portion due to inflation of the airbag is formed on the top surface portion.

Further, a horn switch of a horn is generally arranged in the central area of the steering wheel, and the horn switch has no choice but to interfere with the storage pad of the airbag device in terms of position or structure. As a structure of an airbag device in which a horn switch and a storage pad are integrated, a structure in which a pressure-sensitive membrane switch forming a horn switch is attached to the storage pad is disclosed in Japanese Patent Laid-Open No. 5-16756. According to the configuration disclosed in the publication, the pressure sensitive membrane switch is attached to the outermost layer of resin and covered with leather. When the driver presses the membrane switch with his / her finger, the membrane switch energizes the operating circuit of the horn (horn) to activate the horn. This membrane switch is arranged in a so-called lid portion that expands when the airbag is inflated, and is arranged in an outer region of a hinge portion or a rotation axis that constitutes a rotation center of the lid portion, and is arranged on the storage pad. It extends over a relatively wide range. In addition, the membrane switch, in order to ensure smooth rotation of the lid part,
The lid portion is intermittently connected near the hinge portion or the rotation axis.

[0005]

However, since the horn switch is generally frequently pressed with fingers, tensile stress repeatedly acts on the top surface of the storage pad. On the other hand, in the storage pad having the above-described structure, the horn switch is arranged in the lid portion and the outer region of the lid portion, straddling the rotation axis of the lid portion, and from the vicinity of the central tear line to the edge of the storage pad. It extends widely to the area. Therefore, the deformation of the lid portion is promoted by the pressing operation of the horn switch, and excessive stress is easily repeatedly applied to the thin portion forming the tear line.
Unexpected tear line breaks or breaks may occur. In particular, since the tear line extends from the central area of the storage pad, the pressing operation of the horn switch that extends widely on the storage pad causes a relatively large stress in the tear line that induces tearing of the tear line. Will end up.

Further, the above-mentioned conventional storage pad has a structure in which a horn switch is mounted in a recess formed in the surface layer of the storage pad, and a finishing treatment such as leather is inevitably applied to the passenger compartment side. Therefore, a relatively complicated horn switch mounting process and surface finishing process are required. The present invention has been made in view of the above points, and an object thereof is to include a horn switch that is operated by a pressing operation and to prevent unintended tearing of the storage pad. To provide.

It is another object of the present invention to provide a method for manufacturing an airbag storage pad, which can manufacture such an airbag storage pad in a relatively simple process and can simplify the finishing process. .

[0008]

In order to achieve the above-mentioned object, the present invention has a top surface part having a one-layer structure or a two-layer structure made of an elastic material and a cleaving part of the top surface part when an airbag is deployed. In a storage pad for an airbag provided with a tear line for inducing or promoting the movement and a mounting portion for mounting to a main body portion of the airbag device, a lid portion that rotates when the airbag is deployed and a rotation axis line of the lid portion A storage pad for an airbag is provided, in which a horn switch is embedded along the attachment portion in a region of the top surface portion located outside.

According to the above construction, the horn switch is embedded in the area of the top surface part which avoids the part to be cleaved and the part to be deployed or rotated, so that the lid part is not scattered or scattered when the airbag is deployed. It is possible to prevent the generation or the scattering of the horn switch itself. Also, since the horn switch is located near the mounting part with relatively high rigidity, the operation of the horn switch is directly affected by the airbag superimposed on the storage chamber and the strength of the lid part. Therefore, the stable function or operability of the horn switch is ensured.

In a preferred embodiment of the present invention, on the back surface of the area of the top surface portion in which the horn switch is embedded,
Reinforcing ribs are provided that increase the rigidity of the area. The reinforcing ribs are preferably arranged in a lattice shape along the attachment portion. By providing such reinforcing ribs, the area of the top surface portion where the horn switch is arranged has a high rigidity, and a more stable function or operability of the horn switch is secured.

More preferably, the horn switch is
It consists of a cord-type or sheet-type pressure conductive switch provided with a pressure conductive elastomer. This type of pressure conductive switch is activated or short-circuited by a relatively small compressive force, which enhances the operability of the embedded horn switch. Therefore, such a pressure conductive switch is extremely suitable as the horn switch having the above configuration. In addition, when the driver operates a relatively sensitive horn switch, the pressing force is sensuously reduced, so that the load on the thin portion forming the tear line is reduced. Thus, the horn switch composed of the pressure conductive switch is extremely effective in preventing the tear line from being unexpectedly opened. Further, since the cord-type or sheet-type pressure conductive switch is generally thin and can be processed into an arbitrary shape, it can be embedded in a desired portion of a storage pad in a desired size or range, and It can be integrally molded as an insert when molding the storage pad.

In order to achieve the above object, the present invention also provides:
A manufacturing method for manufacturing the storage pad, comprising molding a first layer of a top surface portion of the storage pad with a first thermoplastic elastomer, and positioning a horn switch at a predetermined position of the first layer. 2. A manufacturing method of an air bag storage pad, characterized in that the second layer of the top surface of the storage pad is molded with the thermoplastic elastomer of No. 2, and the horn switch is interposed between the first layer and the second layer. Provide a way.

[0013] Preferably, the thermoplastic elastomer for molding the layer located on the passenger compartment side is selected from materials having a hardness lower than that of the thermoplastic elastomer for molding the layer positioned on the side opposite to the passenger compartment. Be done. The present invention further provides a manufacturing method for manufacturing the above-mentioned storage pad, wherein a horn switch is positioned in a mold cavity of a molding die for molding the top surface portion of the storage pad by a thermoplastic elastomer, There is provided a method for manufacturing an airbag storage pad, characterized in that the top surface portion is molded with an elastomer, and the horn switch is embedded inside the top surface portion.

Preferably, the horn switch is embedded in the mold cavity so as to be embedded at a depth of 0.5 to 1.5 mm from the vehicle compartment side surface of the storage pad. According to the above manufacturing method, the horn switch can be embedded at a predetermined position in the storage pad in a relatively simple method in the step of forming the storage pad. Therefore, it is possible to eliminate or reduce the influence of the horn switch on the appearance of the storage pad, and to simplify the storage pad finishing process.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic front view of a steering wheel including an airbag storage pad according to a first embodiment of the present invention. 2 is a sectional view of the airbag storage pad taken along the line AA ′ in FIG. 1, and FIG. 3 is a front view of the storage pad showing the arrangement of horn switches in the airbag storage pad shown in FIG. It is a figure.

As shown in FIG. 1, the steering wheel W
Includes a plurality of spokes S extending inward in the radial direction from the handle portion, and an airbag device A arranged in the center of the steering wheel W. Airbag device A
Has a storage pad 1 provided with a top surface portion 3 facing the passenger compartment, and the top surface portion 3 has a tear line 8 arranged in a substantially H shape.
Are formed. The tear line 8 includes left and right tear lines 8a extending in the vertical direction and a central tear line 8b extending in the lateral direction or the vehicle width direction.

As shown in FIG. 2, the storage pad 1 is an injection-molded product having a two-layer structure composed of an upper elastic body layer 4 forming the top surface portion 3 and a lower elastic body layer 5 including a mounting portion 5. Two
It is molded by injection molding by the color molding method. Top part 3
On the back of the V-shaped or U-shaped that locally thins the top surface portion 3.
-Shaped grooves are formed in the area between the left and right mounting portions 5, and the grooves are
A tear line 8a that induces or promotes the cleavage of the top surface portion 3 is configured. A central tear line 8b which cooperates with the tear line 8a to induce or promote the cleavage of the top surface portion 3 is also constituted by a similar groove, and both ends of the tear line 8b are connected to the tear line 8a. Further, the mounting portion 5 is connected to an airbag holding member (not shown). The airbag holding member supports an inflator (not shown) and forms an airbag storage chamber behind the top surface portion 3.
It should be understood that in FIG. 2, the structure of each part is simplified and shown in a form slightly different from the dimensional ratio and detailed structure in the actual design.

As shown in FIG. 2, the horn switch 10 is
It is interposed between the upper elastic body layer 4 and the lower elastic body layer 5.
The horn switch 10 is composed of a pressure conductive switch. The pressure conductive switch is preferably composed of a cord type pressure conductive switch (FIG. 5) or a sheet type pressure conductive switch (FIG. 6) provided with a conductive elastomer.

FIG. 5 shows a cord type pressure conductive switch 12.
FIG. 3 is a partially cutaway perspective view showing a horn switch 10 composed of (hereinafter, referred to as a cord switch 12). The cord switch 12 has a first plain weave wire electrode 14 and a second plain weave wire electrode 16 arranged in an outer layer of elastic silicone rubber.
A plate-like pressure conductive rubber 18 made of silicon rubber containing metal fine particles is interposed between the second plain weave wire electrodes 14 and 16. When the cord switch 12 receives a compressive force, the variable resistance pressing conductive rubber 18 rapidly changes its characteristics from an insulating state to a conducting state due to compressive deformation, and the first and second plain weave wire electrodes 14, 16 Electrically short circuit.

As another suitable horn switch 10, as shown in FIG. 6, a sheet type pressure conductive switch 20 having an insulating sheet can be preferably used. FIG. 6 is a vertical cross-sectional view of the sheet-type pressure conductive switch 20 (hereinafter referred to as the sheet switch 20). The sheet switch 20 includes a frame 22 on the left and right, a first electrode plate 25 and a second electrode plate 27 of a resin film arranged between the frames 22, and an interposition between the first and second electrode plates 25, 27. Insulation sheet 2
And 8 in general. First and second electrode plates 25, 27
Each of the electrodes 24, 2 is formed by vapor-depositing an aluminum foil on the side facing the insulating sheet 28 and is etched into a predetermined shape.
6 is formed. Further, the insulating sheet 28 has an opening 29 formed in a predetermined portion. The sheet switch 20 configured as described above receives the compressive force, and when the first and second electrode plates 25 and 27 come close to each other, the electrodes 24 and 26 are
Contact via the opening 29 and short-circuit. In addition, in FIG. 6, the first and second electrode plates 25 and 27 are shown in FIG.
The part drawn out of the drawing is shown. Further, one of the electrode plates 25 and 27 of the resin film may be replaced with a flick plate.

As shown in FIG. 3, the horn switch 10
Is arranged outside the left and right tear lines 8a extending in the vertical direction substantially in parallel with the tear lines 8a and substantially parallel to the tear line 8b extending in the horizontal direction along the edge of the top surface portion 3. To be done. The upper and lower horn switches 10 arranged substantially parallel to the tear line 8b have upper and lower lid portions 3 formed by tearing the tear lines 8a and 8b.
It is arranged outside of each rotation axis 19 of a and 3b.

FIG. 4 is a back view schematically showing the structure of the back surface of the storage pad 1. The storage pad 1 is provided with lattice-shaped reinforcing ribs 9 on the back surface of the area where the horn switch 10 is embedded. The reinforcing ribs 9 are integrally formed with the lower elastic layer 6, and for example, continuous protrusions having a thickness of 1 mm or more that form a square or rectangular lattice of 20 mm square or less are formed on the back surface of the storage pad 1. The reinforcing ribs 9 formed in this manner increase the rigidity of the portion of the storage pad 1 in which the horn switch 10 is embedded, efficiently disperse the reaction force of the compressive force acting on the horn switch 10, and Reduce the amount of deformation. The form or pattern of the reinforcing ribs 9 is not limited to the above square lattice or rectangular lattice,
It may be formed in an array of various shapes or patterns, such as a triangle or a polygon, or a linear shape, a circular shape, a curved shape, or an irregular shape.

FIGS. 7 and 8 are sectional views of the air bag storage pads according to the second and third embodiments of the present invention. In each drawing, the same reference numerals are attached to the parts or portions that are equivalent or equivalent to the parts or portions in the above-described first embodiment. In the storage pad 1 shown in FIG. 7, the top surface portion 3 is provided with a two-layer structure composed of an upper elastic body layer 4 and a lower elastic body layer 6 over the entire top surface portion 3, and a tear line (in FIG. 8a only is shown) is formed in the central portion 7 of the lower elastic layer 6. Horn switch 10 consisting of a pressure conductive switch
Is inserted between the upper elastic body layer 4 and the lower elastic body layer 5 as in the first embodiment. Also, the horn switch 10
Are embedded at substantially the same positions as those shown in FIGS. 3 and 4. That is, as shown in FIGS. 3 and 4, the horn switch 10 is arranged in an area outside the left and right tear lines 8a, and is substantially parallel to the laterally extending tear lines 8b, and the edge portion of the top surface portion 3 is substantially parallel to the tear line 8b. Are arranged along the lid part 3
It is located in the outer region of each rotation axis 19 of a and 3b. As shown in FIG. 4, the storage pad 1 is also provided with lattice-shaped reinforcing ribs 9 in the region where the horn switch 10 is located, so that the rigidity of the support region of the horn switch 10 is increased.

The storage pad 1 shown in FIG. 8 is an injection-molded product having a one-layer structure, and the tear line (only the tear line 8a is shown in FIG. 8) constitutes the top surface portion 3. It is formed on the back surface of the elastic layer 4. The horn switch 10 is embedded in the elastic layer 4 by insert molding. It is arranged at substantially the same position as that shown in FIGS. That is, the horn switch 10 is shown in FIG.
And, as shown in FIG. 4, the outer area of the tear line 8a,
It is arranged in an area outside the rotation axis 19 along the edge of the top surface portion 3. As shown in FIG. 4, the storage pad 1 further includes a grid-like reinforcing rib 9 in the area where the horn switch 10 is arranged.

According to the storage pad 1 of each of the above-described embodiments, when the area of the top surface portion 3 where the horn switch 10 is located is pressed with fingers, the horn switch 10 receives a compressive force and short-circuits, and the horn (horn ) Energize the operating circuit to activate the horn. The area where the horn switch 10 is inserted or embedded is located outside the area where the tear lines 8a and 8b are arranged, so that the pressing force of the finger is applied to the tear lines 8a and 8b.
b does not act directly, and therefore tear lines 8a, 8b
Unintentional cleavage or breakage of is prevented. Further, since the horn switch 10 is arranged in the outer region of the rotation axis 19, the lid portions 3a and 3b when the airbag is deployed.
Smooth rotation is secured.

Further, the area of the top surface portion 3 where the horn switch 10 is located is provided with a reinforcing rib 9 on the back surface and has a relatively high rigidity. Therefore, a sufficient reaction force against the compression force of the horn switch 10 can be obtained, the deformation of the storage pad 1 against the pressing force of fingers can be suppressed, and the tear lines 8a and 8b can be reliably prevented from being unexpectedly opened or broken.

The present inventor manufactured the air bag storage pads according to the first and second embodiments as follows. After injection molding the lower elastic body layer 5 including the mounting portion 5 and the reinforcing rib 9 with the first thermoplastic elastomer of a predetermined material,
The pressure conductive switch is positioned at a predetermined position of the lower elastic layer 5, and then the upper elastic layer 4 is formed by using a thermoplastic elastomer having a hardness lower than that of the thermoplastic elastomer of the lower elastic layer 5. Injection molded. Thus, the pressure conductive switch is integrally molded with the lower elastic layer 5 and the upper elastic layer 4 interposed therebetween, that is, the horn switch 10 is embedded inside the surface layer (upper elastic layer 4). Storage pad 1 was obtained.

The inventor of the present invention also manufactured the air bag storage pad according to the third embodiment as follows. The storage pad 1 including the mounting portion 5 and the reinforcing rib 9 was injection-molded using a mold capable of insert molding using a thermoplastic elastomer of a predetermined material. In the process of injection molding work, the pressure conductive switch was placed in the mold in the mold opening process or the mold clamping process, and the resin was injected into the mold cavity in the injection process.
Here, the pressurizing conductive switch is positioned in the mold cavity and insert-molded so that it can be embedded at a predetermined depth from the surface of the top surface portion 3, for example, at a depth of 1 mm from the surface. . Thus, the airbag storage pad 1 having a one-layer structure in which the horn switch 10 composed of the pressure conductive switch was embedded was obtained.

The storage pad 1 thus formed not only has a good appearance without being subjected to an excessive finishing treatment, but also has a lid portion from the storage pad 1 when the top surface portion 3 is torn by the expansion of the airbag. Does not cause scattering or dissipation of 3a and 3b. Moreover, the horn switch function of the storage pad 1 can prevent unintentional tearing or tearing of the tear lines 8a and 8b as described above, can ensure smooth rotation of the lid portions 3a and 3b, and can be reinforced. The ribs 9 can obtain a sufficient reaction force against the compression force of the horn switch 10.

[0030]

According to the structure of the present invention as set forth in claims 1 and 2, the horn switch which is actuated by the pressing operation is provided, and the storage of the air bag which can prevent the unintentional tearing of the storage pad. It becomes possible to provide a pad. According to the configuration of the present invention as set forth in claims 3 and 4, such an airbag storage pad can be manufactured by a relatively simple process, and the finishing process can be simplified. It becomes possible to provide a method.

[Brief description of drawings]

FIG. 1 is a schematic front view of a steering wheel including an airbag storage pad according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the airbag storage pad taken along the line AA ′ in FIG.

FIG. 3 is a front view of a storage pad showing an arrangement of horn switches in the storage pad for an airbag.

4 is a back view schematically showing the structure of the back surface of the storage pad shown in FIG.

FIG. 5 is a partially cutaway perspective view showing a horn switch composed of a cord-type pressure conductive switch.

FIG. 6 is a vertical sectional view of a sheet-type pressure conductive switch.

FIG. 7 is a sectional view of an airbag storage pad according to a second embodiment of the present invention.

FIG. 8 is a sectional view of an airbag storage pad according to a third embodiment of the present invention.

[Explanation of symbols]

 W Steering wheel S Spoke A Airbag device 1 Storage pad 3 Top surface part 4, 6 Elastic body layer 5 Mounting part 10 Horn switch 12 Cord type pressure conductive switch 20 Sheet type pressure conductive switch

Claims (4)

[Claims] 1. A top surface portion of a one-layer structure or a two-layer structure made of an elastic material, a tear line for inducing or promoting tearing of the top surface portion when the airbag is deployed, and for attaching to a main body portion of an airbag device. An air bag storage pad including a mounting portion of the horn, and a horn that extends along the mounting portion in a region of the lid portion that rotates when the airbag is deployed and the top surface portion that is located outside a rotation axis of the lid portion. Storage pad for airbag, which has a switch embedded. 2. The airbag storage pad according to claim 1, wherein a reinforcing rib for enhancing rigidity of the region is provided on the back surface of the region of the top surface portion in which the horn switch is embedded. 3. A manufacturing method for manufacturing the storage pad according to claim 1 or 2, wherein the first layer of the top surface portion of the storage pad is molded with a first thermoplastic elastomer. The horn switch is positioned at a predetermined position of the layer, the second layer of the top surface portion of the storage pad is molded by the second thermoplastic elastomer, and the horn switch is interposed between the first layer and the second layer. A method of manufacturing a storage pad for an airbag, which is characterized in that. 4. A manufacturing method for manufacturing the storage pad according to claim 1 or 2, wherein a horn is formed in a mold cavity of a mold for molding the top surface portion of the storage pad with a thermoplastic elastomer. A method for manufacturing an air bag storage pad, comprising positioning a switch, molding the top surface portion with a thermoplastic elastomer, and burying the horn switch inside the top surface portion.