JPH0948301A - Interior trim material for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide interior trim material for vehicles which is not only inexpensive and excellent in productivity but also capable of absorbing stress caused by collision enough and minimizing secondarily generating stress to the at most, so that passengers are protected and secured their own body. SOLUTION: Synthetic resin grid-like ribs 2 are provided which are disposed within the interior trim material and have various heights (h) so that the root portions 21 of the ribs form an undulating grid surface, wherein the grid-like ribs 2 provide for the respective root portion 21 of the ribs 2 an uniform thickens t1 which is gradually rescued toward the tips of the ribs 2, and covering plates 3 are integrally molded at the root portion 21 of the grid-like ribs 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interior member for a vehicle, which is provided inside an interior part for a vehicle such as an armrest and a door trim to reduce a shock when a collision accident occurs and protects a passenger's body. .

[0002]

2. Description of the Related Art In recent years, vehicles such as automobiles are required to have a high degree of safety to protect passengers not only from a frontal collision but also from a side collision (hereinafter referred to as "side collision"). ing. As one of the measures, an attempt has been made to give a shock absorbing performance to an armrest, a door trim and the like on the side of the vehicle which directly hits the waist or abdomen of the occupant during a side collision. Specifically, as shown in FIG. 7, the interior member 9 is intended to be disposed between the interior trim panel 7 and the vehicle interior trim and the inner panel 7. As the interior member 9, a member made of a resin foam such as a hard urethane foam or foam beads has already been proposed (Japanese Patent Laid-Open No. Hei 4).
-293640 publication). On the other hand, the present inventor pays attention to the fact that the lattice rib can absorb the impact by buckling deformation, and introduces the lattice rib excellent in productivity as an interior member for a vehicle arranged inside a door trim or the like. I have continued to research. Such a vehicle interior member is shown in FIG. Here, the lattice-shaped rib 8 obtained by conventional injection molding has been manufactured with a constant wall thickness t ₅ at the tip of the rib even if the height of each rib is different from the design surface to be undulated. In the electric discharge machining for forming the cavities for the grid-like ribs, the electrode shape is machined, but the thickness t ₅ of the rib tip is determined, and the thickness t ₅ and the draft of the mold are made constant for each rib, and the electric discharge machining is performed. This is because the rib length was determined by adjusting the depth of. And this was easier to design.

[0003]

However, in the conventional grid-shaped ribs 8, the heights of the ribs are different due to the undulations of the design surface, so that the energy absorption amount for absorbing the impact is also changed.
Therefore, there are cases in which shock absorption becomes inconvenient. For example, referring to FIG. 8, a collision element 6 having a weight of 20 kg and a collision speed of 6 m
In the case of collision at / s, since the rib height h ₁ of the grid-like rib is sufficient in the α portion, the colliding element is absorbed by the buckling and deformation of the rib, and the colliding element has a bottom (to the inner panel). The deformation subsides (Fig. 9). However, at the β portion in FIG. 8, the rib height h ₂ is low, and since the rib height h ₂ is low, the rib base wall thickness t ₄ is also α.
Since the rib is much thinner than the wall thickness t ₃ , the rib itself is likely to be buckled and deformed, and the energy of the colliding element M cannot be absorbed and the rib bottoms out. In such a case, the impact force F (FIG. 9) that cannot be completely absorbed may be transmitted to the occupant to cause damage.

[0004] The present invention solves the above problems,
An object of the present invention is to provide a vehicle interior member that is low in cost, highly productive, sufficiently absorbs a side impact load, suppresses a secondary load as much as possible, protects an occupant's body, and can ensure safety. And

[0005]

In order to achieve the above object,
The gist of the first aspect of the present invention is to be arranged inside a vehicle interior component,
It is provided with a synthetic resin lattice-shaped rib in which the rib height is changed so that the lattice surface of the rib root portion is undulated. The lattice-shaped rib keeps the thickness of each rib root portion constant and further increases toward the tip. The vehicle interior member is characterized in that its thickness is gradually reduced. The vehicle interior member of the second invention,
The top plate is integrally formed at the root of the grid-like rib of the first invention. The vehicle interior member according to a third aspect of the present invention is characterized in that, in the first aspect or the second aspect, each rib relating to the grid-like rib is thinned with the same gradient from the rib root to the tip. To do.

According to the vehicle interior member of the present invention, since the thickness of each lattice rib is gradually reduced from the root to the tip, the thickness is thin when an external impact is applied. Since the buckling deformation progresses in order from the tip portion of the lattice rib, shock absorption can be performed conveniently. Even if the thickness of the rib tip portion varies depending on the rib height, the thickness of each rib root portion is constant, so that a partial bottoming phenomenon as in the conventional case does not occur. Although the initial load is somewhat increased at a place where the rib height is low, the final stage of ending the shock absorption by buckling deformation depends on the thickness of the rib root portion, so that the shock load can be absorbed almost uniformly over the whole. In addition, when the top plate is integrally formed at the base of the grid-like rib, the flow of the resin raw material at the time of molding is good and the molding becomes easy.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a vehicle interior member (hereinafter simply referred to as "interior member") according to the present invention will be described in detail with reference to the drawings. 1 is a perspective view of an automobile door as an example incorporating the interior member of the present invention, FIG. 2 is a vertical cross-sectional view of the door trim lower of FIG. 1, FIG. 3 is a partially enlarged perspective view of the interior member of FIG. 2, and FIG. Graph of generated load against deformation amount, FIG. 5 is a graph of static generated load at 50% against rib tip wall thickness, and FIG. 6 is 50% against rib root thickness.
It is a graph of the static generated load at the time of compression.

In FIG. 1, reference numeral A is an armrest provided on the inner surface of the door Z, reference numeral R is a door trim upper, and a door trim lower 6 is formed below the armrest A. The interior member 1 of the present invention is the door trim. It is installed in the lower 6. The outer shape of the interior member 1 is appropriately set according to the size and shape of the door trim lower 6. On the outer peripheral surface of the interior member 1, a plurality of projecting pieces (not shown) for fixing are integrally formed as needed. The projecting piece is fixed to a mounting portion integrally formed on the inner surface of the armrest A with a screw or the like.

However, the interior member 1 is composed of the grid-shaped ribs 2 and the top plate 3 integrally formed at the roots thereof, and as shown in FIG. 2, the thickness is about 1.5 mm to 2 mm made of synthetic resin. On one surface of the top plate, a plurality of plate-shaped bodies are respectively vertically bulged and integrally formed with grid-shaped ribs 2 intersecting each other. Top plate 3
Undulates along the shape of the door trim lower 6, and the grid-shaped ribs 2 change the rib height to form an undulating shape in which the grid surface of the rib root part undulates. The door trim lower 6 and the inner panel 7 serve as interior members. It is arranged between (FIG. 2).

The grid-shaped rib 2 is formed so that the rib thickness is gradually reduced as it goes away from the rib root portion 21 and that the rib has a desired draft. Then, the wall thickness t ₁ of each rib root portion 21, 21, ... Is constant (here, about 1.
5 mm), and the rib thickness is thinned from the rib root portion 21 toward the tip with the same gradient (FIG. 3). Since the rib wall thickness decreases from the rib root portion 21 toward the tip, buckling deformation progresses in order from the tip portion with a thin wall thickness against impact, and the structure is such that impact absorption can be performed conveniently. There is. In addition, even if the rib height h of each grid-like rib 2 changes, the wall thickness t ₁ of each rib root 21 is kept constant,
Since the rib thickness is thinned toward the tip with the same gradient, the grid-shaped ribs 2 with respect to the maximum deformation amount when an impact is applied.
The load generated in each part of is almost equalized. Therefore, even in a place where the rib height h is low, a situation in which the rib bottoms out prior to other portions does not occur.

For example, in FIG. 4, the thickness t of the rib base portion 21 is
Rib height h is 40 mm, 60 mm, and 80 m, respectively, with ₁ as 1.5 mm and the draft angle as constant as 0.25 degrees.
The test value which prepared the test piece made into m, and investigated the produced | generated load characteristic with respect to the deformation amount at the time of applying an impact load is shown. here,
The test piece is a grid-like rib 2 (sample size 120 mm × 120 mm) having a rib pitch of 30 mm × 30 mm, and the top plate 3 has a thickness of 2.5 mm. As the impact load, a collision speed of 6 m / s and a collision element having a weight of 20 kg are collided. Fig. 4 shows that the rib height is 40 mm, although the rib height is a little too low and tends to bottom when the rib height is 40 mm.
At 60 mm and 80 mm, the ribs 21 have the same wall thickness t ₁ so that the load generated in the latter half (C
Part) is almost the same. In the figure, the higher the rib height h is 40 mm, 60 mm, and 80 mm, the smaller the initial generated load is because the rib tip wall thickness t ₂ becomes smaller as the rib height h increases, and This is because the energy absorption of is smoothly progressed.

Further, FIG. 5 shows that the rib base portion 21 has a wall thickness t ₁
(Here, t ₁ = 1.5 mm) is kept constant, and an experimental value obtained by examining the static load generated at 50% compression with respect to the rib tip wall thickness when the rib draft is 0.25 ° is shown. FIG.
In the experimental condition, the test sample is entirely compressed at a compression speed of 50 mm / min. The graph of FIG. 5 shows that if the thickness of the rib base portion 21 is constant, the generated load does not change much even if the rib tip thickness t ₂ changes. Since the rib draft is the same, when the rib tip wall thickness t ₂ is 0.8 mm, the rib height h is naturally higher than when the rib tip wall thickness t is 1.2 mm. 8
In the vicinity of mm, the initial load can be absorbed a little more than the others.

Thus, by keeping the thickness t ₁ of the rib base portion 21 constant, it is possible to eliminate partial bottoming of the interior member 1 and effectively absorb energy. The preferable range of the wall thickness t ₁ is ₁ mm to 3 mm, more preferably ₁ mm to 2 mm. FIG. 6 shows the rib root portion 21.
The graph showing the static load generated at the time of 50% compression with respect to the wall thickness t ₁ of the above is supported. The experimental condition of FIG. 6 is that the test sample was subjected to full compression at a compression speed of 50 mm / min. It has been confirmed by experiments that if the thickness of the rib base portion 21 exceeds 3 mm, it becomes difficult to keep the generated load low. The height h of the grid-shaped rib 2 can be selected as appropriate, but various experiments have shown that the height h is 4
Significant results have been obtained for shock absorption in the range of 0 mm to 120 mm. When the height h of the grid-shaped rib 2 is 40 mm, a bottoming tendency appears as can be seen from FIG.

By the way, in the above-mentioned experiment of FIG. 5, the lattice-shaped ribs 2 having the same vertical and horizontal directions and square openings are used, and two types of rib pitches of 32.5 mm and 30 mm are examined. As is clear from FIG. 5, the lattice ribs 2 having a rib pitch of 30 mm have a larger energy absorption amount as the lattice ribs 2 become denser. A preferable rib pitch of the grid-shaped rib 2 is 20 m.
It is m to 180 mm. When the rib pitch is larger than 180 mm, the space ratio of the grid-like ribs 2 is high and the shock absorbing ability is deteriorated. On the contrary, when the rib pitch is smaller than 20 mm, the grid-like ribs 2 are too dense and the load generated at the time of side collision is small from the initial stage. This is because it becomes large and it becomes difficult to commercialize it by injection molding. In view of easiness of manufacturing the product, 20 mm to 60 mm is a further suitable range in order to maintain a high impact absorbing ability. In the present embodiment, the grid-like ribs 2 having a rib pitch with square openings are used, but the grid-like ribs 2 with rectangular or even polygonal openings (for example, honeycomb-shaped ribs) can be used.

The top plate 3 is formed integrally with the root portion 21 of the grid-shaped rib 2. The top plate 3 is integrated with the grid ribs 2 mainly for improving the flow of the resin raw material during injection molding and for facilitating the molding of the interior member 1. The thickness of the top plate 3 is preferably about 2 mm. Yes (Preferable range: 1.5
mm-3.0 mm). If the wall thickness of the top plate 3 is less than 1.5 mm, it becomes difficult for the resin to spread around the thin ribs, and deformation during mold release tends to occur. On the other hand, when the thickness of the top plate 3 exceeds 3.0 mm, the rigidity is increased, but since the weight is blindly increased, the thickness of the top plate 3 is appropriately selected according to the product.

A thermoplastic resin such as polypropylene, olefin elastomer, polyethylene resin or ABS resin is used as a molding material for the interior member 1 which forms the top plate 3 and the grid-like ribs 2.

The interior member 1 of the above-mentioned configuration thus configured
Is the grid-shaped rib 2 in which the rib height h is changed and the grid surface of the rib root part is undulated. Even if there is some difference in the distribution of the initial generated load, the generated load at the final stage of the deformation amount Since the impact load is received as a whole in the same manner, the energy absorption works effectively. It is possible to eliminate the problems due to the partial bottoming that has been seen in the past and to suppress the secondary load as much as possible. By integrally molding the top plate 3 at the root of the grid-shaped ribs 2, injection molding can be performed at low cost and with high productivity, as compared with a conventional hard urethane foam or the like. Further, the ribs of the grid-like rib 2 are thinned in thickness from the rib root portion 21 toward the tip end with the same gradient. Therefore, if the initial generated load range is exceeded, the interior member 1 is the same in each portion. It becomes a shape and becomes an interior member having a good energy absorption balance.

In the present invention, the present invention is not limited to those shown in the above embodiments, but can be variously changed within the scope of the present invention depending on the purpose and application. Not only the armrest shown in this embodiment, but also the door trim, dashboard, console box, glove box, knee protector, and other interior parts 1 for vehicle interior parts can be used. In the present invention, the interior member 1 may be molded as a single body, but may be integrally molded with the interior product as a part of a vehicle interior product. In that case, the shape of each part, the constituent material, and the like can be appropriately selected according to the function, application, required strength, and the like.

[0019]

As described above, the interior member for a vehicle of the present invention has a quality-improving structure by suppressing secondary load against side impact load as much as possible and further reducing cost as an injection molded product. Excellent effect in terms of cost.

[Brief description of drawings]

FIG. 1 is a perspective view of an automobile door as an example that incorporates a vehicle interior member of the present invention.

FIG. 2 is a vertical cross-sectional view of the door trim lower shown in FIG.

3 is a partially enlarged perspective view of the vehicle interior member of FIG.

FIG. 4 is a graph of generated load against deformation amount.

FIG. 5 is a graph of statically generated load at 50% compression with respect to rib tip wall thickness.

FIG. 6 is a graph of statically generated load at 50% compression with respect to the wall thickness of the rib root portion.

FIG. 7 is a vertical cross-sectional view of a prior art automobile door, II of FIG.
-Corresponds to the line II arrow view.

FIG. 8 is a vertical sectional view of a conventional door trim lower.

FIG. 9 is a graph showing the relationship between the amount of deformation and the generated load.

[Explanation of symbols]

1 Vehicle Interior Member 2 Lattice Rib 21 Rib Root 3 Top Plate t ₁ Rib Root Thickness

Claims (3)

[Claims] 1. A grid rib (2) made of synthetic resin, which is disposed inside an interior part for a vehicle, and which has a rib surface which is undulated by changing the rib height. The vehicle interior member is characterized in that the thickness of each rib root portion is made constant, and further, the thickness is gradually reduced toward the tip. 2. The vehicle interior member according to claim 1, wherein a top plate (3) is integrally formed at a root of the lattice rib. 3. The vehicle interior member according to claim 1 or 2, wherein each rib of the grid-like ribs has a thickness that is thinned from the root of the rib toward the tip at the same gradient.