JP2001163147A - Air bag module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air bag module allowing components to be miniaturized and lightened. SOLUTION: A retainer 12 mounted to a steering wheel 26 is made of thermoplastic. A horn circuit guide member 25 is disposed around a central opening 12a on a flat part of the rear plate of the retainer 12. The guide member 25 is crimped onto a trapezoidal base table 13 formed around the steering wheel 26 by substantially one circle. The base table 13 serves as a reinforcing rib of the retainer 12. The guide member 25 is metal foil such as copper foil. Several places in which the guide member 25 disperses are contact switch parts 25x contacting with a contact 44 of a horn circuit. The contact switch parts 25x is coated with abrasion resistant coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a module of an airbag device for protecting a vehicle occupant. In particular, the present invention relates to an airbag device module for a driver mounted on a steering wheel, which is a so-called floating horn (or entire horn) airbag module which also serves as a horn (alarm) switch.

[0002]

2. Description of the Related Art In order to protect occupants in the event of a vehicle collision, airbag devices for a driver, a passenger seat, a rear seat, a side, and the like are used in almost all current passenger cars. Equipped. The airbag device is generally mounted on a vehicle as a module including a bag, a retainer, an inflator, a cover, and the like. The bag is normally stored in the module in a folded state. The retainer fixes the end of the bag to the vehicle body. The inflator generates gas for inflating and deploying the bag when the vehicle collides.

[0003] Among the above various airbag devices, those for a driver are mounted on a steering wheel and deploy a bag in front of the driver. A typical steering wheel has an annular rim. A boss is located at the center of the inside of the rim. The boss is fixed to the steering shaft of the vehicle body. The rim and the boss are connected by a plurality of spokes. Of the airbag modules mounted on such a steering wheel, the one that also serves as a horn (alarm) switch is called a floating horn type (or an entire horn type).

A conventional example of a steering wheel equipped with this type of driver airbag device is disclosed in Japanese Patent Application Laid-Open No. 11-20710. The airbag module of this publication is attached to a steering wheel via a horn switch mechanism. The horn switch mechanism includes a horn plate formed in a plate shape from a conductive metal material. A coil spring is interposed between the rear side (the vehicle body side) of the horn plate and the steering wheel. An airbag module is fixed to the front side (occupant side) of the horn plate.

[0005] The horn plate can contact a fixed contact of the horn circuit. Normally (when the airbag module is not pressed), the horn plate and the fixed contact are separated by the urging force of the coil spring. By pressing the airbag module, the horn plate contacts the fixed contact and the horn sounds. In the steering wheel disclosed in this publication, the horn plate is a plate frame-shaped integral member, so that the number of parts supporting the plate is reduced, and the operational feeling of the switch is improved. However, a plate frame-shaped integral member made of a metal material has a problem that it is difficult to reduce the size and to combine components, and the weight increases.

[0006] The present invention has been made in view of the above problems, and has as its object to provide an airbag module capable of realizing miniaturization and weight reduction of components.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, an airbag module according to the present invention is an airbag module mounted on a steering wheel and also serving as a horn switch; A retainer that can be attached to the retainer in a floating manner, an airbag whose base is fixed to the retainer and folded, an inflator that is fixed to the retainer and that releases airbag deployment gas, and covers the driver side of the retainer and the folded airbag Module cover,
A horn circuit conducting member disposed substantially around the steering wheel on the steering wheel side (back side) of the retainer; and wherein the retainer (or a component attached thereto) is a non-conductive member. Wherein the horn circuit conducting member is crimped to the retainer (or a component attached thereto).

[0008] A retainer (or a component attached thereto)
Can be formed by injection molding or the like from a thermoplastic resin material, for example. The use of a resin material facilitates molding and processing, and can reduce the weight of the retainer.
As a result, the weight of the entire airbag module can be reduced. In addition, if the retainer is an injection-molded product, it can be combined with other parts, and the degree of freedom in shape design increases. Since the horn circuit conducting member is crimped to the retainer or a component attached to the retainer, component compositing is achieved. Therefore, the number of parts and the number of assembly steps can be reduced.

In the airbag module according to the present invention, the horn circuit conducting member may be made of a metal foil and may be hot-pressed to a substantially flat portion of the retainer or a member attached thereto. In this case, rather than a separate frame-shaped metal horn plate,
Overwhelmingly lightweight.

Further, in the airbag module of the present invention, several dispersed portions of the horn circuit conducting member are contact switch portions for contacting the contacts of the horn circuit, and the contact switch portions are provided with a wear-resistant coating. Is preferably applied. The wear-resistant coating can improve durability while achieving weight reduction. In addition, since the contact switch portions are present at several dispersed locations, the horn can be made conductive regardless of where the horn switch is pressed.

In the airbag module of the present invention, it is preferable that the horn circuit conducting member has a horn harness connecting electrode terminal fixing portion formed at the same time as crimping. In this case, there is an advantage that the number of production steps can be further reduced.

Hereinafter, description will be made with reference to the drawings. FIG.
FIG. 1A is a perspective view of a retainer of an airbag module according to one embodiment of the present invention as viewed from the rear side, and FIG.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 2 is an exploded perspective view of the airbag module including the retainer of FIG. 1 and the steering wheel as viewed from the near side. FIG. 3 is an exploded perspective view of the airbag module and the steering wheel as viewed from a rear side.
FIG. 4A is a cross-sectional view illustrating details of a connection portion between the airbag module and the steering wheel. In FIG. 4A, the steering wheel 26 is illustrated including an outer portion such as the spoke portion 26x. FIG. 4B is a circuit diagram showing a horn conduction circuit. FIG.
FIG. 5A is a schematic cross-sectional view for explaining the hot pressing operation of the horn conductive circuit member to the retainer, and FIG.
FIG. 6 is an enlarged view of a portion X in FIG.

As shown in FIGS. 2 and 3, etc., the airbag module 10 of this embodiment is roughly composed of the following components. (1) The retainer 12 attached to the steering wheel 26. (2) A folded airbag 14 having a base fixed to the retainer 12 (see FIG. 4A, not shown in FIGS. 2 and 3). (3) A module cover 16 that covers the front side of the retainer 12 and the airbag 14. (4) Inflator 1 for releasing airbag deployment gas
8.

In the following description, the driver side (the side viewed in FIG. 2) is described as the front side, and the vehicle body side (the side viewed in FIG. 3) is described as the back side. The center of the steering wheel 26 is called the inside, and the side far from the center of the steering wheel 26 is called the outside.

First, the module cover 16 will be described. As shown in FIGS. 2, 3, and 4 (A), the module cover 16 is attached to the front side of the retainer 12. The module cover 16 is made of a synthetic resin. The module cover 16 is provided with tear lines 16a and 16b as shown by a two-dot chain line in FIG. The module cover 16 receives the force to inflate and deploy the bag when the airbag device is operated, and
a, 16b tear open. Note that FIG.
What is indicated by 6c is a recess for fitting an emblem (not shown).

The left, right, and lower parts of the module cover 16
As best shown in FIG. 2, the spoke portions 161, 16
2, ie, a portion protruding outward from the center of the wheel. The left and right spoke portions 161 are provided symmetrically. As shown in FIG. 3, the leg piece 1 protruding to the rear side is located inside the rear side surface of the spoke portion 161 of the cover 16.
63 are formed. The leg pieces 163 partition the center part on the rear side and the side ends of the module cover 16. A leg 165 protruding to the rear side is also formed inside the rear side surface of the spoke 162 of the cover 16. Same leg piece 165
Separates the center part and the lower end part on the rear side of the module cover 16.

As shown in FIG. 3, two locking pieces 166 are provided on the left and right sides between the spokes 161 and 162 on the rear side of the module cover 16. These locking pieces 166 are arranged along the side peripheral edge of the module cover 16. Three locking pieces 166 are also provided between the left and right spokes 161 along the upper peripheral edge of the module cover 16. Each locking piece 166 is a leg piece 1
It protrudes further back than 63 or 165.
Each locking piece 166 has an opening 167 formed therein.

Next, a description will be given of the retainer 12, which is a component having the characteristic features of the present invention. As shown in FIGS. 2 to 4, the retainer 12 is a member that holds the bag 14 and the inflator 18, and is attached to the steering wheel 26 in a floating manner. In the present embodiment, the retainer 12 is made of a thermoplastic plastic (for example, ABS, PS, PC, PA, PAR, PBT, PET).
And their alloys). Plastics may or may not be fiber reinforced. The retainer 12 may be either an injection molded product or an extruded product.

A central opening 12a is opened at substantially the center of the retainer 12. In this central opening 12a,
The front part of the inflator 18 is fitted. Around the central opening 12a of the retainer 12, four small holes 12b
Is open. The ring 24 and the bolt 20 for fixing the inflator 18 are inserted into the small hole 12b.

As shown in FIG. 2 or FIG. 4A, support plates 121 and 122 are provided on the front side of the retainer 12.
Are formed so as to protrude forward. Each of the support plates 121 and 122 opposes the outer surface of the leg portion 163 or 165 of the cover 16 when the module cover 16 is assembled into the retainer 12. The left and right support plates 121 are reinforced by rib-shaped support pieces 123.

The retainer 12 has a module cover 16.
An engagement port 126 is provided at a position corresponding to each of the locking pieces 166. Each engagement opening 126 is an opening which is cut out in a rectangular shape, and each engagement piece 1 of the module cover 16 is formed.
66. In each engagement opening 126, the engagement protrusion 12 is provided.
7 are provided. The engagement protrusion 127 is provided in the engagement opening 1.
26 protrudes from the edge near the outer peripheral edge toward the inside of the opening. The locking projection 127 engages with the opening 167 of the locking piece 166 of the module cover 16.

As shown in FIGS. 1 and 3, a horn circuit conducting member 25 is provided around the central opening 12a on the flat surface on the back surface of the retainer 12. Conductive member 2
5 is crimped on a trapezoidal base 13 which is formed so as to make substantially one round around the steering wheel 26. The base 13 also functions as a reinforcing rib of the retainer 12. The conductive member 25 is a metal foil such as copper. The horn circuit conducting members 25 are dispersed at several points, and the contact switch portions 25 contact the contacts 44 (see FIG. 4B) of the horn circuit.
x. In the contact switch section 25x, the base 13 is raised higher than other portions. The contact switch unit 25x includes tin / lead, tin, nickel,
A wear-resistant coating is applied by surface plating of silver, gold, or the like. The wear-resistant coating improves durability (wear strength) or electrical contact characteristics.

The pressing of the horn circuit conducting member 25 to the flat surface on the back surface of the retainer 12 is generally called "IVONDI".
NG "(see, for example," Nikkei Mechanical ", 1999.2, no.533 for details of" IVONDING "). According to this method, a conductive circuit pattern is formed on a thermoplastic resin.
Horn circuit conducting member 2 (made of thermoplastic)
5 (made of metal foil such as copper). This method has advantages that it is non-polluting because no chemical solution is used and no exhaust gas or wastewater is generated, or it is relatively low in capital investment and low in running cost, so that it is low in cost.

An outline of the crimping operation will be described with reference to FIG. In this method, a stamping die 70 is used as shown in FIG. The stamping die 70 is made of steel, and has a desired convex pattern 71 formed by an engraving machine. In the case of the present embodiment, a stamping die having a pattern 71 that makes a round around the steering wheel 26 is used. The stamping die 70 is heated to a predetermined temperature before the pressure bonding operation (for example, about 220 ° C. when the retainer 12 is PBT (polybutylene terephthalate)).

At the time of the crimping operation, reference numeral 7 in FIG.
A thermoplastic resin material α (retainer 12) to be processed is placed on the stage indicated by 5, and a metal foil β (a horn circuit conducting member 25) is placed on the thermoplastic resin material α. When the heated stamping die 70 is pressed against the metal foil β and pressed, the pattern 71 pushes the metal foil β off and the thermoplastic resin material α is heated and softened. At this time, the metal foil β is added to the softened thermoplastic resin material α.
As a result, the hot-pressed portion Y is formed. Finally, the excess metal foil is manually or automatically peeled off.

Horn circuit conducting member 25 to retainer 12
At the same time as the formation of the hot crimping portion Y, the electrode terminal fixing portion X for horn harness connection is formed. This simultaneous step can further reduce the number of working steps. In order to form the electrode terminal fixing portion X, as shown in FIG.
The pattern 73 having 2 is formed. When the stamping die 70 is pressed as described above, a hole γ having a T-shaped cross section is formed in the retainer 12, as shown in FIG. A metal foil β is pressed on the peripheral surface.

As described above, since the horn circuit conducting member 25 is crimped to the retainer 12, the components can be combined, the number of components and the number of assembling steps can be reduced, and the degree of freedom of components can be improved.

The module cover 16 and the retainer 1
2 is assembled in a so-called snap-on manner. That is, each locking piece 166 of the module cover 16 is inserted into the corresponding engagement opening 126 of the retainer 12. The locking piece 166 enters the engagement opening 126 while flexing inward due to elasticity, and after being inserted sufficiently deeply, returns to its original shape again due to elasticity. At this time, the opening 167 of the locking piece 166 is engaged with the locking projection 127
And the module cover 16 is assembled to the retainer 12.

Next, the bag 14, the ring 24 and the inflator 18 will be described. As shown in FIG. 4A, the bag 14 has a bag shape and the module cover 16
It is folded and housed in the central part on the back side. The ring 24 shown in FIG. 2, FIG. 3 and FIG. 4 (A) is a frame member made of steel or the like, and is for fixing the base end of the bag 14. The inner periphery of the ring 24 is located at the center opening 1 of the retainer 12.
2a. Bolts 20 are planted at four corners of the ring 24.

The inflator 18 shown in FIG. 2, FIG. 3 and FIG. 4 (A) generates gas for expanding the bag 14. A gas ejection port 18a is formed on a front side surface of the inflator 18. Gas is released into the bag 14 from the jet port 18a. This inflator 1
8 is provided with a body flange 18b. The flange 18b projects outward from the side surface of the inflator 18 and has a square outer periphery.
Small holes 18c are formed at four corners of the flange 18b.

The bag 14, ring 24 and inflator 18 are attached to the retainer 12 as follows. As shown in FIG. 4A, the inflator 18
Is mounted on the back side of the retainer 12. The front part of the inflator 18 is located at the center opening 12 a of the retainer 12.
And protrudes from the front of the retainer 12.
On the near side of the retainer 12, the ring 24 is assembled by inserting the bolt 20 into the small hole 12 b of the retainer 12. Between the ring 24 and the retainer 12,
The base end (opening end) of the bag 14 is sandwiched.
The bolt 20 is inserted into the small hole 12b of the retainer 12 and the small hole 18c of the inflator 18, and projects to the back.
A nut 22 is screwed into the bolt 20 from the back side, and the ring 24, the open end of the bag 14, and the inflator 18 are integrally attached to the retainer 12.

The airbag module 10 having the above-described structure is snap-on to the steering wheel 26 of the vehicle body structure by the retainer 12 and the locking device 30 (FIG. 4A) provided on the steering wheel 26. Installed.

The steering wheel 26 is shown in FIGS.
As shown in FIG. 4A, the main body 26a is made of an aluminum casting or the like and has a horizontally long plate shape. This body 26
A hole 26b is formed at a center position on the near side of a.
A steering wheel shaft (not shown) is fitted and fixed in the hole 26b. The steering wheel 26 is provided with pin support portions 26x and 26y to which the pins 32 of the locking device 30 are attached. Pin support 26x
Are provided so as to protrude at both left and right ends of the steering wheel 26. The pin support 26y is provided below the steering wheel 26 via a forked connecting member 26z. The ends of the support portions 26x and 26y are formed in a claw shape. With this claw-shaped end, the locked retainer 12 can be pressed from the outside.

The locking device between the airbag module 10 and the steering wheel 26 is shown in FIGS.
As shown in FIG. 1A, a pin 32 attached to the steering wheel 26 and a locking window 31 provided in the retainer 12 are provided. The pin 32 is fixed to a surface 26p of the pin support portions 26x and 26y of the steering wheel 26. A spring 36 is arranged on the outer periphery of the pin 36. The locking window 31 forms a pin insertion hole 12h through which the pin 32 can be inserted and fixed. The locking window 31 includes a cover 40.
Covered with. The pin 32 and the locking window 31 are, for example, disclosed in Japanese Patent Application No. 11-334572 or Japanese Patent Application
The structure disclosed in JP-A-348647 can be used.

Next, the configuration of the horn conduction circuit will be described with reference to FIG. As shown in FIG. 4A, a horn contact 44 is provided on the front side of the steering wheel 26.
Is provided. When the airbag module 10 is mounted on the steering wheel 26, the horn contact 44 is used for the contact switch 2 of the horn circuit conducting member 25.
5x (see FIGS. 1 and 3).

The horn conduction circuit includes a relay R as shown in FIG. The contact switch 25x of the horn circuit insertion member 25 is connected to one end of the relay R. On the other hand, a horn contact 44 of the steering wheel 26 is connected to the other end of the relay R via a power supply and a vehicle body ground circuit. This relay R is also connected to a circuit including a horn H and a power supply. When the contact switch section 25x and the horn contact 44 come into contact, the relay R is activated, the circuit of the horn H is closed, a voltage is applied to the horn H, and the horn H sounds.

When the airbag module 10 is mounted on the steering wheel 26, the contact switch portion 25x of the horn circuit insertion member 25 crimped to the retainer 12
And the horn contact 44 of the steering wheel 26
The positional relationship is such that contact is possible as shown in FIG. The figure shows a state in which the module cover 16 is not pressed (a state in which the horn is not sounded), and the contact switch section 25x and the horn switch contact section 44 are separated. Therefore, the horn H of the horn conduction circuit shown in FIG.
No voltage is applied to, and the horn H does not sound.

In this state, when the module cover 16 is pushed in the direction F (rearward direction) in FIG. 4A, a force is applied to the retainer 12 from the edge of the locking piece 163 of the module cover 16. At this time, the spring 36 contracts, and the retainer 12 moves toward the steering wheel 26 (backward direction).
Then, the contact switch unit 25x and the horn contact 44 come into contact, a voltage is applied to the horn H via the relay R, and the horn H sounds.

Since the contact switch portions 25x are provided at several dispersed locations on the hoop 25, the horn H can be sounded regardless of where the module cover 16 is pressed. Further, since the contact switch portion 25x is provided with a wear-resistant coating, durability (wear strength) or electric contact characteristics are improved. Therefore, the contact with the horn contact 44 is performed stably.

[0040]

As is apparent from the above description, according to the present invention, there is obtained an effect that the components of the floating horn type airbag module can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 (A) is a perspective view of a retainer of an airbag module according to one embodiment of the present invention as viewed from a back side;
FIG. 1B is a cross-sectional view taken along line AA of FIG.

FIG. 2 is an exploded perspective view of the airbag module including the retainer of FIG. 1 and a steering wheel as viewed from the near side.

FIG. 3 is an exploded perspective view of the airbag module and a steering wheel as viewed from a rear side.

FIG. 4A is a cross-sectional view showing details of a connecting portion between an airbag module and a steering wheel, and FIG. 4B is a circuit diagram showing a horn conduction circuit.

FIG. 5 (A) is a schematic cross-sectional view for explaining a hot pressing operation of a horn conductive circuit member to a retainer.
FIG. 5B is an enlarged view of a portion X in FIG. 5A.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Airbag module 12 Retainer 12h Pin insertion hole 13 Base 14 Airbag 16 Module cover 16a, 16b
Tear line 18 Inflator 18a Gas outlet 18b Body flange 20 Bolt 24 Ring 25 Horn circuit conducting member 25x Contact switch 26 Steering wheel 26a Main body 26b Hole 26x, 26y Pin support 30 Locking device 31 Locking window 32 Pin 36 Spring 40 Cover 44 Horn contact 70 Stamping die 71, 73 Pattern 72 Projection 75 Stage α Thermoplastic resin material β Metal foil γ hole X Electrode terminal fixing portion Y Hot crimping portion 121, 122 Support plate 126 Engagement hole 127 Engagement protrusion 161, 162 Spoke part 163, 165
Leg piece 166 Locking piece 167 Opening R Relay H Horn

Claims (4)

[Claims] 1. An airbag module mounted on a steering wheel and also serving as a horn switch; a retainer mounted on the steering wheel in a floating manner; an airbag having a base fixed to the retainer and folded; In addition, an inflator that releases airbag deployment gas, a module cover that covers the driver side of the retainer and the folded airbag, and a steering wheel side (rear side) of the retainer
A horn circuit conducting member disposed substantially around the steering wheel; and the retainer (or a component attached thereto).
Is made of a non-conductive member, and the horn circuit conducting member is crimped to the retainer (or a component attached thereto). 2. The airbag according to claim 1, wherein the horn circuit conducting member is made of metal foil, and is hot-pressed to a substantially flat portion of the retainer (or a member attached to the retainer). module. 3. The horn circuit conducting member according to claim 1, wherein the horn circuit conductive member has a plurality of dispersed contact points that are in contact with the contacts of the horn circuit, and the contact switch portions are provided with a wear-resistant coating. The airbag module according to claim 2, wherein 4. The airbag module according to claim 2, wherein an electrode terminal fixing portion for connecting a horn harness is formed on the horn circuit conducting member at the same time as crimping.