JPS62263014A - Manufacture of impact energy absorbing structure - Google Patents

Abstract

PURPOSE:To simply manufacture an impact energy absorbing structure having a predetermined amount of energy absorption by a method wherein a covering is manufactured by molding an energy absorber, which is manufactured in advance, as an insert. CONSTITUTION:A energy absorber 12 is manufactured in advance by reaction injection molding and, after that, set through a mounting member 14 to a top force 19. In addition, the top force 19 and a bottom force 20 are equipped with the molding surface for the predetermined cavity allowing a covering 13 to mold when the forces are closed. Further, on the top force 19, engaging pieces 19a, each of which is same as an engaging piece 6 arranged on a boss plate 3 allowing the mounting member 14 to anchor thereon, and an anchoring piece 19b, which is same as an anchoring piece 7 arranged on the boss plate 3 missing a claw 7a, are provided. The predetermined impact energy absorbing structure is obtained by pouring molding material in the predetermined cavity made by closing a mold 18 and releasing from the mold after the mold is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing an impact energy absorbing structure disposed above a steering wheel boss portion of an automobile or the like.

<Prior Art> Conventionally, this type of impact energy absorbing structure is known from JP-A-59-230849, JP-A-60-29355, and the like.

These impact energy absorbing structures are made of rigid foam FUR
It consisted of an energy absorber made of brittle plastic such as @PS, and a cover body that covered the surface of the energy absorber with a horn switch body interposed.

The manufacturing methods for these impact energy absorbing structures include manufacturing each part in advance and assembling it using screws, etc., or manufacturing the cover body and horn switch body in advance from the perspective of reducing assembly man-hours and manufacturing costs. It was proposed that the horn switch body be placed in a predetermined position inside the cover body, and then a brittle plastic material would be injected into the cover body to integrate the energy absorber. By the way, in conventional impact energy absorbing structures of this type, the amount of energy absorbed is 1
Q: It was decided by.

Therefore, when managing the energy absorption amount of the impact energy absorbing structure, it is sufficient to measure the weight of the energy absorbing body itself.

However, in the latter manufacturing method mentioned above, the energy absorber is integrally manufactured by injection molding a brittle plastic material into the cover body, so when trying to measure the weight, it is only possible to measure the weight including the cover body. It wasn't clear.

1. Usually, the cover body is made of a soft plastic such as soft FOR-PVC or a soft foam thereof, and there is a risk that the variation in its weight will be larger than the variation in weight of a brittle plastic with a high expansion ratio. .

Therefore, even if the weight of the manufactured impact energy absorbing structure is measured, there is a risk that the variation in the weight of the cover body will be larger than the variation in the weight of the energy absorber, and the amount of energy absorbed by the impact energy absorbing structure may be controlled. It wasn't easy.

The present invention solves the above-mentioned problems, and aims to provide a method for manufacturing an impact energy absorbing structure for a steering wheel, which can be manufactured easily and the amount of energy absorbed can be easily managed. .

Means for Solving the Problems〉 The method for manufacturing an impact energy absorbing structure according to the present invention includes an energy absorbing structure made of brittle plastic and a cover covering the surface of the energy absorbing structure, which is arranged on the upper part of the steering wheel post. A method for manufacturing an impact energy absorbing structure consisting of a body and a body, in which the energy absorbing body is manufactured in advance, and a cover body is manufactured using this energy absorbing body as an insert, thereby solving the above-mentioned problems. It is something to do.

<Operations and Effects of the Invention> In the method for manufacturing an impact energy absorbing structure according to the present invention, an energy absorber is manufactured in advance, and a cover body is manufactured using this energy absorber as an insert, Since the energy absorber is prefabricated by itself, it is possible to measure the weight of the energy absorber itself, which determines the energy absorption amount of the impact energy absorbing structure, and only a predetermined weight of the energy absorber can be used as an insert. By molding the cover body, it is possible to easily manufacture an impact energy absorbing structure having a predetermined amount of energy absorption, and the energy absorption amount can be easily managed.

<Example> Embodiments of the present invention will be described below based on the drawings.

First, the impact energy absorbing structure 11 manufactured by the method of the first embodiment will be explained.

As shown in FIGS. 1 and 2, this impact energy absorbing structure 11 has a substantially square truncated pyramid shape disposed above the boss portion l of the steering wheel W, and is made of hard foam FUR-PS, etc., as in the past. The energy absorber 12 is made of a brittle plastic, and the cover body 13 is made of a soft plastic such as soft foamed PUR@PS, which covers the surface of the energy absorber 12.

This energy absorber 12 has a substantially rectangular truncated pyramid shape, and when attaching the steering shaft S, oak) N, or the energy absorbing structure ll itself to the boss plate 3, which will be described later. Recesses 12a@12b and 12c are provided so as not to interfere with the engaging piece 6 and the locking piece 7 of the boss plate 3 used for this purpose.

The cover body 13 has a box-like shape that covers the area other than the bottom surface of the energy absorber 12, and has a mounting member 14 embedded in the lower end surface thereof, which is used when attaching the impact energy absorbing structure 11 to the boss plate 3. As shown in FIG. 5, is a substantially rectangular ring-shaped body made of hard plastic such as PA/ABS-PP, and extends upward from each of the four sides of the base 14a and is embedded in the cover body 13. It is equipped with similar hook pieces 14b and 14c. The hook piece 14b projects perpendicularly from the base 14a, and the hook piece 14c projects so that its tip is inclined inward. The hook pieces 14c are mutually deformable so as to spring elastically open outward, and when the cover body 13 is molded, they sandwich the bottom periphery of the energy absorber 12 and attach the energy absorber 12 via the mounting member 14.
It is formed so that it can be set in a mold.

Further, on the lower surface of the base 14a of the mounting member 14.

Two protruding pieces 14d that protrude inwardly are formed on one of the two sides on which the hook piece 14b is formed, and a U-shaped locking part 14e is formed on the other side along that side.

Then, the projecting pieces 14d engage with the retaining pieces 6, which are riveted at predetermined positions on the top surface of the boss plate 3, and the locking parts 14e are also riveted at predetermined positions, as shown in FIG. By sliding the mounting member 14 together with the impact energy absorbing structure 11 from the right side in FIG. It is configured to be attached to 1. Note that a claw 7a for preventing removal is cut and raised in the locking piece 7 of the boss plate 3 to prevent the impact energy absorbing structure 11 from coming off after installation.

Further, 2 is a boss, 5 is a lower cover, and the steering wheel W to which this impact energy absorbing structure 11 is attached has a horn button B that operates the horn not in the impact energy absorbing structure 11 but in the spoke portion 4. There is.

Next, manufacturing of this impact energy absorbing structure 11 will be described.

First, the energy absorber 12 is formed by reaction injection molding (R
(IM molding) and have a predetermined weight prepared.

Then, attach the bottom periphery of the energy absorber 12 to the hook piece 14c.
14c to attach the energy absorber 12 to the mounting member 1.
4, and then, as shown in Fig. 3, the upper and lower molds 1
The mounting member 1 is attached to the upper mold 19 of the mold 18 consisting of 9 and 20.
The energy absorber 12 is set via 4. In addition,
The upper and lower molds 19 and 20 mold the cover body 13 (R
It is equipped with a predetermined mold surface for a cavity that allows for molding (injection molding). The upper mold 19 also includes an engaging piece 6 arranged on the boss plate 3 that can lock the mounting member 14, and an engaging piece 19a similar to the locking piece 7 that does not have a claw 7a. A piece 19b is formed. therefore,
Similarly, when the mounting member 14 is locked to the boss plate 3,
Mounting member 1 holding energy absorber 12 on upper mold 19
4 can be locked.

Thereafter, as shown in FIG. 4, the mold 18 is closed,
By injecting a molding material into a predetermined cavity, molding, and releasing the mold after opening the mold, a predetermined impact energy absorbing structure 1 can be obtained.
1 can be obtained.

Then, by locking the attachment member 14 to the boss plate 3, the impact energy absorbing structure 11 can be attached to the boss portion 1 of the steering wheel W and used.

Therefore, in this way, the impact energy absorbing structure 11
When manufacturing the energy absorber 12, it can be manufactured using only the energy absorber 12 of a predetermined weight as an insert, so it can be easily manufactured and the energy absorber 12 can be manufactured in advance.
has a predetermined energy absorption amount, and the energy absorption amount of the impact energy absorption structure 11 can be easily managed.
An example will be explained.

As shown in FIGS. 6 and 7, the impact energy absorbing structure 21 manufactured by the method of the second embodiment has an insert 26 and a holder 27 between the upper surface of the energy absorber 22 and the cover body 23. The energy absorber 22, on which the horn switch body 31 is disposed, is made of the same material as the energy absorber 12 of the first embodiment, has an approximately truncated quadrangular pyramidal external shape, and has a steering shaft S in the center. (or oak) without interfering with N, and the horn switch body 3
It is provided with a through hole 22a through which one lead wire 34Φ35 is inserted. The energy absorber 22 also has an engagement piece 6 provided on the boss plate 3 at a predetermined position on the bottom surface thereof.
and recesses 22b and 22c that do not interfere with the locking piece 7, and recesses 22d and 22et that allow a locking piece 29a of an upper die 29, which will be described later, to lock a protrusion 26a on the inner circumference of the insert 26 when molding the cover body 23. - Prepared.

The cover body 23 has a thin wall portion 23b on the top surface along its periphery.
is formed, and a portion surrounded by the thin wall portion 23b serves as a pressing portion 23a when the horn is activated, and is made of the same material as the cover body 13 of the first embodiment and has approximately the same shape.

The insert 26 is made of hard plastic such as FA-PP-ABS, covers the four sides of the energy absorber 22, and also covers the upper surface with the horn switch body 31 and the holder 2.
It has a box shape that is spaced apart upward by a height of 7 and covered, and a protrusion 26a is formed on the inner circumference of the lower end over the entire circumference. In addition, the thin wall portion 23 of the cover body 23 is attached to the back surface of the earthen wall of the insert 26.
A V-shaped groove 26c is formed in the lower awn of b, and this V-shaped groove 26c is broken after forming the cover body 23, which will be described later.
The part surrounded by 6c is configured to be movable downward as a pressing operation part 26b.

The holder 27 is a FAφPP@A similar to the insert 26.
A space made of hard plastic such as BS, whose shape is brought into contact with the entire upper surface of the energy absorber 22 and also with the back surface of the inner circumferential side φ upper wall of the insert 26 to enable normal operation of the horn switch body 31. It is configured so that it can be formed.

The horn switch body 31 is inserted into the push actuation section 26 of the insert.
A movable contact member 32 made of a leaf spring that comes into contact with the b1 surface
and the fixed side contact member 3 arranged at the bottom of the holder 27.
3, these contact members 32 and 33 are fixed to the holder 27 with an insulating sheet 37 and a rivet 36, and are provided with contacts 32a*33a corresponding to predetermined positions. Further, a lead wire 34 is connected to the movable contact member 32, a lead wire 35 is connected to the fixed contact member 3.3, and the lead wires 34 and 35 are electrically connected to the positive electrode or negative electrode side of the horn operating circuit, respectively. It is configured to

In this impact energy absorbing structure 21, a mounting member 24 made of sheet metal and having a substantially rectangular ring shape as shown in FIG. It is configured to be installed on. By the way.

This mounting member 24 has a base 24a with a mounting hole 24b, and similarly to the mounting member 14 of the first embodiment, the mounting member 24 has an engaging piece 6 riveted to the boss plate 3 and a locking piece provided with a claw 7a. A protruding piece 24C and a locking portion 24d corresponding to No. 7 are provided to protrude from the base 24a.

Next, manufacturing of the impact energy absorbing structure 21 according to the second embodiment will be explained.

First, as in the first embodiment, the energy absorber 22
are manufactured by RIM molding and prepared in a predetermined weight.

Then, the horn switch body 31 and the holder 27 are housed in the insert 26, and the energy absorber 22 is also housed therein. Note that when storing the energy absorber 22, the insert 26 must be slightly expanded due to the protrusion 26a formed on the insert 26, but if it is difficult to store the energy absorber 22, Alternatively, a slit may be formed at a predetermined portion around the insert 26 to allow the insert 26 to be easily expanded, or the energy absorber 22 may be separated and stored in sections.

7, as shown in FIG. 8, the energy absorber 22 together with the horn switch body 31 is set in the upper mold 29 of the mold 28 consisting of upper and lower molds 29 and 30 via the insert 26. The upper and lower molds 29 and 30 are provided with a predetermined mold surface for molding so that the cover body 23 can be molded (RIM molding - injection molding), and the upper mold 29 has an insert 2
A hook piece 29a capable of undercutting and fixing the protrusion 26a of 6 is formed at a predetermined position, and the insert 26 holds the energy absorber 22 through this hook piece 29a, and the upper mold 2
It will be set to 9.

Thereafter, as shown in FIG. 9, the mold 28 is closed,
Molding material is injected into a predetermined cavity to form the mold, and the mold is released after opening.

After releasing the mold, the V-shaped groove 26c of the insert 26
1. As shown in FIGS. 10 and 11, the pressure m 23 a of the cover body 31 is pressed to break the V-shaped groove 26c. Further, the mounting member 24 is fixed to the insert 26 with a screw 25.

Thereafter, by connecting the lead wires 34 to 35 to predetermined locations and locking the mounting member 24 to the boss plate 3, the ms energy absorbing structure 21 can be attached to the boss portion 1 of the steering wheel W and used. .

Therefore, in this way, the impact energy absorbing structure 21
When manufacturing the energy absorber 22, the cover body 23 is molded using the energy absorber 22, the horn switch body 31, etc. as inserts, as in the first embodiment. Since the weight of the impact energy absorbing structure 21 can be measured, the amount of energy absorbed by the impact energy absorbing structure 21 can be easily managed.

Further, after the cover body 23 is formed, the fragile V-shaped groove 26c of the insert 26 is broken so that the horn switch body 31 can be operated, and when the cover body 23 is formed before being broken, the insert 26, the holder 27, or the energy absorber Since the horn switch body 31 is completely sealed by the 22nd year upper mold 29, when the cover body 23 is molded.

The molding material of the cover body 23 does not enter the horn switch body 31, and the horn switch body 31 after molding
This prevents problems such as malfunction of the horn switch due to molding material entering.

In addition, a V-shaped groove 26c is formed in the insert 26 as a configuration in which the horn switch body 31 can be sealed during molding of the cover body 23, and the fragile portion of the insert 26 can be broken after molding to make the horn switch body 31 operable. Others, 13th
Hole 2, such as insert 260 as shown in FIG.
61 are continuously formed, and a thin film 262 which closes the upper part of these small holes 261 and withstands the pressure during molding of the cover body 23 is formed.
The insert 360 as shown in FIGS.
As shown in FIG. 2, the pressing actuating portion 361 is separated in advance at the lower position of the thin wall portion 23b of the cover body 23, and the pressing actuating portion 361 is adhered with an adhesive force that can withstand the pressure during molding the cover body 23. The adhesive portion may be broken after the body 23 is formed.

Also, the horn switch body 31 used in this second embodiment
In the above, a switch using a leaf spring is shown, but of course, this switch body can also be made of rubber, coil springs, etc., as shown in FIG.
A horn switch main body 41 with a biasing means 44 interposed to separate the two, or a horn with a conductive rubber (piezoelectric type) 54 interposed between contact members 52 and 53 as shown in FIG. It may be the switch body 51.

Furthermore, the impact energy absorbing structure 21 manufactured in the second example has the impact energy absorbing structure 21 manufactured in the first example because the cover body 23 is molded with the insert 26 arranged around the entire inner circumference thereof. Cover body 23 compared to structure body 11
The occurrence of sink marks on the outer surface is suppressed, and the product can be manufactured with a good appearance.

Furthermore, in the impact energy absorbing structure 21 manufactured in the second embodiment, the insert 26 is attached (=1 member 24 is fixed with a screw 25, and the boss portion l is attached via the attachment member 24.
Of course, the protruding piece 24C or the locking part 24d of the mounting member 24 may be provided on the insert 26 itself, or the insert 2 may be attached directly from the side surface of the boss plate 3.
6 may be attached by screwing, or the insert 26 may be configured to have locking legs that can be attached under the boss plate 3.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the usage mode of the impact energy absorbing structure manufactured in the first embodiment of the present invention, and shows the I-I section in FIG. Top view of the steering wheel using the 3rd
The figure is a cross-sectional view showing the same example when set in a mold, Figure 4 is a cross-sectional view showing the same example when molding, and Figure 5 shows the mounting member and boss plate used in the same example. Perspective view, No. 6
The figure is a sectional view of how the impact energy absorbing structure manufactured in the second example is used, and shows the ■-vt portion in Figure 7, and Figure 7 is a steering wheel using the impact energy absorbing structure according to the same example. Fig. 8 is a cross-sectional view showing the same example when it is set in a mold, Fig. 9 is a cross-sectional view showing the same example when molding, and Fig. 1θ shows the insert and the like used in the same example. FIG. 11 is a partial sectional view of the holder after molding, FIG. 12 is a sectional view of the insert used in the same example when it is broken, and FIG. 13 is an insert showing another example. and a partial perspective view of the holder, FIG. 14 is a partial cross-sectional view after turning and molding, FIG. 15 is a cross-sectional view showing the state at breakage when turning, and FIG. 16 is a portion of the insert and holder showing still another example. A perspective view, FIG. 17 is a partial cross-sectional view after the folding is formed, FIG. 18 is a cross-sectional view showing when the fold is broken, and FIG.
The figure is a perspective view showing the mounting member used in the same example.
The figure is a sectional view showing another example of the horn switch body used in the same embodiment, and FIG. 21 is a sectional view showing still another example of the horn switch body. l...Boss section. 11.21...Impact energy absorption structure, 12-2
2...Energy, -absorber. 13.23...Cover body, W...Steering wheel. Patent application Toyoda Gosei Co., Ltd. 1; 2; Nini Patent Attorney Ii 1) Akio: 11-So

Claims (1)

[Claims] A method for manufacturing an impact energy absorbing structure disposed above a steering wheel boss portion and comprising an energy absorber made of brittle plastic and a cover body covering the surface of the energy absorber, the method comprising manufacturing the energy absorber in advance. 1. A method for manufacturing an impact energy absorbing structure, comprising: forming the cover body using the energy absorbing body as an insert;