JPH03136948A - Cover case for air bag - Google Patents

Abstract

PURPOSE:To prevent the free end sections of reinforcing nets and any portion other than a thin walled section from being exposed to the surface of a cover case, and from being damaged respectively by connecting the free end sections of the paired reinforcing nets by means of a connecting band sewed on to the free end sections in such a way that the connection can be separated when an air bag is expanded. CONSTITUTION:Gas is quickly released from a gas generator by impact due to the collision of a vehicle and the like, the thin walled section 25 of a cover case 21 is ruptured by the expanding pressure of an air bag 10. At the time of rupture, the free end sections 35 of paired reinforcing nets 33 are connected with each other via a connecting band 36, a sewing thread 37 sewed on to one side furnished with loops 40 of the connecting band 36 will never come out of the connecting band 36, the free end section 35 of one of the reinforcing nets 33 which is sewed on to one side of the connecting band 36 thereby will never be separated from the connecting band 36. The sewing thread 37 sewed on to the other side where the loops are cut off, however will come out of the connecting band 36 with ease while being frayed, the free end section 35 of the other one of the reinforcing nets 33, which is sewed onto the other side of the connecting band 36 is thereby easily separated from the connecting band 36. Paired releasing sections 27 which are ruptured in this case, are surely separated with no interference with the rupture of the thin walled section 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a cover body for an airbag that protects occupants from impacts such as collisions in automobiles and the like.

(Prior Art) Airbag devices for protecting occupants from collisions and other shocks in automobiles and the like are disclosed in, for example, Japanese Patent Application Laid-open No.
The one shown in Publication No. 5 is known.

This airbag device covers a folded airbag with a cover body, causes gas to flow into the airbag to inflate it, and ruptures the cover body during the inflation to cause the airbag to protrude from the cover body. , which prevents the driver from colliding with the steering wheel rim or the windshield in front of the vehicle, as well as absorbing the impact in the event of a collision.

The cover body has a breaking groove on the back surface to form a thin part that breaks as the airbag inflates, and a pair of open parts on both sides of this thin part break as the airbag inflates. It opens like a hinge. Furthermore, reinforcing nets with free ends arranged on both sides of the thin wall portion are insert-molded inside the pair of open portions to prevent breakage from occurring in portions other than the thin wall portion when the cover body breaks. This also prevents the pair of openings from being broken into small pieces and scattered.

In manufacturing this cover body, a reinforcing net is inserted and molded by injecting a resin material into a molding die in which a reinforcing net is set. When setting this reinforcing net in a mold, a pair of reinforcing nets are set on both sides of the protrusions forming the thin part of the cover of the mold, and
The free ends of each reinforcing net are hooked and held by a plurality of protrusions protruding from both sides of the protruding strip of the molding die.

(Problem to be solved by the invention) Conventionally, cover bodies have been manufactured as described above, but
Since the free end portions of each reinforcing net are set by hooking them onto a plurality of protrusions protruding from the molding die, workability is poor and the free end portions of the reinforcing nets cannot be reliably set in a predetermined position. Moreover, the free end portion of the reinforcing net may come off the protrusion and become misaligned due to the injection pressure or foaming pressure of the resin material injected into the molding die during molding of the cover body.

As a result, the free end of the reinforcing net that is insert-molded inside the cover body may be misaligned, and the free end of the reinforcing net may be exposed on the surface of the cover body, or when the cover body is broken, parts other than the thin parts may be There were problems such as parts breaking.

The present invention has been made in view of these points, and it is an object of the present invention to provide a cover body for an airbag in which the free ends of a pair of reinforcing nets are reliably arranged at predetermined positions on both sides of the thin part of the cover body. This is the purpose.

[Structure of the invention]

(Means for Solving the Problems) The present invention covers an airbag 1o that is normally placed in a folded state and expands due to the inflow of gas, and a thin wall portion 25 that is torn as the airbag 10 expands. In the cover body 21 made of an elastic material, in which a pair of reinforcing nets 33 are insert-molded inside, the free end portions 35 of the pair of reinforcing nets 33 are exposed on both sides of the thin wall portion 25. are connected by a connection band 36 sewn to the free end 35 so that they can be separated when the airbag 10 is inflated.

(Function) In the present invention, since the free ends 35 of the pair of reinforcing nets 33 are connected via the connecting band 36, the free ends 35 of the pair of reinforcing nets 33 are formed when the cover body 21 is formed. In addition to being able to reliably set the free end portion 35 at a predetermined position in the mold, it is also possible to prevent the free end portion 35 from shifting due to the injection pressure or foaming pressure of the resin material injected into the mold. The free ends 35 of the pair of reinforcing nets 33 can be positioned at predetermined positions on both sides of the thin portion 25.

Furthermore, when the airbag 10 is inflated, the cover body 2
As the inflation pressure of the airbag 10 is applied to the thin wall portion 25 of the first thin wall portion 25 and the thin wall portion 25 is ruptured, the connection between the free end portions 35 of the reinforcing nets 33 of the pair is released via the connecting band 36. Furthermore, since the free ends 35 of the pair of reinforcing nets 33 are located at predetermined positions on both sides of the thin portion 25 of the cover body 21, the reinforcing net 33 is reliably broken at the thin portion 25.

(Example) Hereinafter, the configuration of an example of the present invention will be described with reference to the drawings.

FIG. 2 shows a steering wheel for an automobile, in which a boss portion 3 is provided at the center of an annular rim portion 1 with a plurality of spoke portions 2 interposed therebetween.

As shown in FIG. 1, this boss portion 3 has a metal cylindrical boss 4 that is fitted and fixed to a steering shaft (not shown), and a boss plate 5 is mounted on the top of this boss 4. Fixed by welding.

An airbag device 7 is disposed above the boss portion 3. In this airbag device 7, a base plate 8 as a fixing member is attached to the boss plate 5 via an attachment means (not shown). The periphery of the opening 11 is fixed by an annular fixing plate 12 and a plurality of fixing devices 13 such as rivets and screws, and the airbag 10 is normally arranged in a folded state.

In addition, a gas generator 1 is installed in the opening 9 of the base plate 8.
4 is disposed, and this gas generator 14 is fixed by a fixing member 13 of the base plate 8 at a flange portion 15 on the outer periphery. Note that a plurality of blowouts [ ] 16 from which gas is blown out are provided at the upper portion that fits inside the airbag IO.

A cover body 21 is fixed to the edge of the base plate 8 so as to cover the airbag 10. This cover body 21
has a cylindrical base 22 fixed to the base plate 8;
A horizontal upper surface portion 23 connected to the upper portion of the base portion 22 is integrally formed of an elastic material such as urethane foam. This cover body 21 has an upper surface portion 23.
A thin wall portion 25 is formed on the back surface of the airbag by a break groove portion 24 having a 7-shaped cross section, and this thin wall portion 25 allows the airbag to break as the airbag 1G expands, as shown in FIG. The center break line 263 and the break lines 26b on both sides thereof are formed into a substantially H-shape, and a pair of open portions 27 are formed.
is formed.

Further, a reinforcing body 31 is integrally embedded inside the cover body 21 by insert molding.

As shown in FIG. 3, this reinforcing body 31 has a frame-cylindrical belt part 32, and a pair of reinforcing nets 3 made of a net material with a relatively coarse structure are attached to each opposing side of the belt part 32.
3 are integrally connected. This pair of reinforcing nets 3
3 is sewn with a sewing thread 34 with the lower edge wrapping around the belt part 32, and the thin part 2 of the cover body 21 is
Connecting bands 3 are attached to each free end portion 35 located on both sides of 5.
6 is applied and sewn with a sewing thread 37, and the free ends 35 are connected.

This connecting band 36, as shown in FIGS. 4 and 5,
For example, a general plain weave bandage is used, but this bandage has a single weft thread 39 woven into a plurality of warp threads 38, and loops 40 of the weft thread 39 are provided on both sides to prevent the warp threads 38 from fraying. Therefore, when using the connecting band 36, the loops 40 on the negative side edge are cut so that the warp threads 38 can be easily unraveled from one side edge as shown in FIG. The configuration is such that the connection between the free ends 35 of the pair of reinforcing nets 33 is easily released when the bag 10 is inflated.

In the reinforcing body 31, as shown in FIG. 27 to the inside of the base 22, and the free ends 35 of the pair of reinforcing nets 33 are connected to the cover body 2.
Connecting bands 36 are embedded in both sides of the thin portion 25 at the center of the reinforcing net 33 and connect the free ends 35 of the pair of reinforcing nets 33 .

Then, when manufacturing the cover body 21, since the free ends 35 of the pair of reinforcing nets 33 of the reinforcing body 31 are connected via the connecting band 36, the reinforcing body 31 is The free ends 35 of the pair of reinforcing nets 33 can be easily attached to predetermined positions simply by setting them in the molding die.

Furthermore, when injecting the resin material into the molding die in which the reinforcing body 31 is set, since the free ends 35 of the -° pair of reinforcing nets 33 are connected via the connecting band 36, the resin material is injected into the molding die. The position of the free end portion 35 can be prevented from shifting due to the injection pressure and foaming pressure of the resin material.

Therefore, in the cover body 21 manufactured in this manner, the free end portions 35 of the reinforcing net 33 are reliably embedded in predetermined positions on both sides of the thin portion 25.

In the airbag device 7, gas is rapidly released from the gas generator 14 into the airbag 10 due to an impact such as a car collision, so the airbag IO rapidly inflates. During the expansion, the thin part 25 of the cover body 21 is broken by the expansion pressure. At this time, the cover body 21 is broken at the top surface 23 from the center break line 261 and both side break lines 26b,
The pair of opening parts 27 rotate upward like a hinge, and the airbag 10 deploys toward the driver, preventing the driver from colliding with the rim part 1 of the steering wheel or the glass in front of the driver, and preventing a collision. Absorbs the shock caused by

When the cover body 21 breaks, a pair of reinforcing nets 33
The free ends 35 of the connecting belt 36 are connected to each other via the connecting band 36, and the sewing thread 37 sewn on one side of the connecting band 36 having the loop 40 does not come off from the connecting band 36, and the connecting band 3
Free end 3 of one reinforcing net 33 sewn on one side of 6
5 and the connecting band 36 do not separate, but the sewing thread 37 sewn on the other side where the loop 40 is cut easily frays and comes off from the connecting band 36 as shown in FIG. The other reinforcing net 33 sewn on the other side
The free end portion 35 and the connecting band 36 are easily separated, and the thin portion 25
There is no problem with the breakage, and the pair of open portions 27 broken at the thin portion 25 are reliably separated.

Furthermore, as described above, the free end portions 3 of the pair of reinforcing nets 33
5 are embedded in predetermined positions on both sides of the thin wall portion 25 of the cover body 21, it is possible to reliably prevent breakage from occurring at locations other than the thin wall portion 25, and also to reliably prevent fragments from scattering when the cover body 21 breaks. be able to.

Note that when the airbag 10 is inflated, the pair of reinforcing nets 33
In the above embodiment, in order to easily release the connection between the free ends 35 of the bandage, the loop 4 on one side of the bandage is
However, the strength of the connecting band 36 itself may be weak, so that the connecting band 36 itself is broken when the thin part 25 of the cover body 21 is broken. The sewing thread 37 to be sewn onto the free ends 35 of the pair of reinforcing nets 33 is made of a weak thread such as cotton thread, and when the thin part 25 of the cover body 21 breaks, the sewing thread 3
7 may be cut so that the connecting band 36 and the free end portion 35 of the reinforcing net 33 are separated.

〔Effect of the invention〕

According to the present invention, the free ends of the pair of reinforcing nets are connected by the connection band sewn to the free ends so that they can be separated when the airbag is inflated. The free ends of the pair of reinforcing nets can be reliably arranged, and the free ends of the reinforcing nets can be reliably prevented from being exposed on the surface of the cover body or from being broken in areas other than the thin parts. can.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the airbag cover body of the present invention, Fig. 2 is a plan view of the steering wheel, Fig. 3 is a perspective view of the reinforcing body, and Figs. 4 and 5 are connections. It is a perspective view of a band. IO...Air bag, 21...Cover body, 25--Thin wall portion, 33--Reinforcement net, 35--Free end portion, 36--Connection band. Invented on October 24, 1989 Invented by Yoshitaka Ishiguro

Claims (1)

[Claims] (1) It covers an airbag that is normally placed in a folded state and inflates when gas flows in, and has a thin part that ruptures as the airbag expands, and has free ends on both sides of the thin part. In a cover body made of an elastic material in which a pair of reinforcing nets are insert-molded inside, the airbag is inflated by a connection band sewn to the free ends of the pair of reinforcing nets. An airbag cover body characterized in that the airbag cover body is connected so as to be releasable at times.