JPH04193689A - Vehicle body structure - Google Patents

Abstract

PURPOSE:To ensure required rigidity, while reducing a body weight, by forming with light metal the skelton members, joined each other, of a vehicle and increasing the thicknesses of the parts of the skelton members, which contribute much to the vehicle rigidity, together with mutually connecting these parts whose thickness is increased. CONSTITUTION:A center pillar 1 and a side sill 3, which are joined each other to constitute skelton members of a vehicle, are formed into an integrated body, by extruding aluminum, material, light metal. In this case, as for both center pillar 1 and side sill 3, the thicknesses of the parts which contribute much to the rigidity of the vehicle are increased. In order words, the thicknesses of both outer wall 9a and inner wall 9b lying in the width direction of the vehicle is made larger than that those of a front wall 11a and a rear wall 11b, while the thicknesses of the upper wall 10a and lower wall 10b of the side sill 3 are made larger than those of an outer wall 12a and an inner wall 12b. Next, the groove 14 of the center pillar 1 is fitted into the flange 7 of the side sill 3, while the lower end 16 of the outer wall 9a is engaged with the stepped part 3a of the side sill 3. Then, the center pillar 1 is made to abut on the upper wall 10a of the side sill 3, and both 1 and 3 are joined together by spot welding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) This invention relates to a vehicle body structure used in a monocoque structure of an automobile.

(Prior Art) The weight of current automobiles tends to gradually increase due to the increase in various equipment, and a 1000cc vehicle weighs about 1 ton. However, the ideal weight is about 670-68'Ok at 1000cC, as has been the case in the past.
g, and various improvements have been made with the aim of achieving this.

In general, the monocoque structure of an automobile consists of pressing steel plates to form various frame members and panel materials, and sequentially joining these members by spot welding or the like to construct a white body.

[Problems to be Solved by the Invention] In order to reduce the weight of such a structure, it is sufficient to reduce the thickness of the iron plate itself, or there are limits to the formation of various skeletal members.

Therefore, materials such as aluminum and resin are attracting attention, and in this case, the possible material selections are: (1) A combination of aluminum, resin, etc. and iron plate.

■ Everything is made of aluminum.

■ A combination of aluminum and resin materials.

There are three types of things that can be considered.

However, in order to achieve the ideal of weight reduction, four
It is necessary to reduce the weight by approximately 0%, and it is difficult to combine the aluminum material (2) with a steel plate.

On the other hand, in the cases of ■ and ■, it is not so difficult to achieve the ideal weight reduction, but in the case of ■, the problem is how to secure the necessary rigidity, and in the case of ■ The difficulty of ensuring rigidity becomes even greater.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle body structure that can ensure necessary rigidity while achieving sufficient weight reduction by using light metal such as aluminum.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention molds mutually connected frame members of a vehicle body from a light metal, and reduces the contribution of these frame members to the rigidity of the vehicle body. The larger parts are made thicker, and these thicker parts are used to connect them to each other.

(Function) By molding the vehicle body frame members from light metal, it is extremely easy to reduce the weight of the vehicle body.

In addition, the parts of this frame member that contribute greatly to the rigidity of the vehicle body are made thick, and the two thickened parts are connected to each other, making it easy to ensure the rigidity of the vehicle body.

(Example) This invention will be described in detail below.

FIG. 1 shows a first embodiment of the present invention, in which a center pillar 1 and a side sill 3 are used as frame members of a vehicle body that are connected to each other.
This shows that. Both the center pillar 1 and the side sills 3 are integrally formed by extrusion of aluminum, a light metal, eliminating the need for the conventional work of separately molding the inner panel and outer panel and joining them by spot welding. Manufacturing becomes extremely easy.

In addition, both the center pillar 1 and the side sills 3 have thick walls in the portions that make a large contribution to the rigidity of the vehicle body. That is, the outer wall 9a and the inner wall 9b in the vehicle width direction are formed thicker than the front wall 11a and the rear wall 11b. Also side sill 3
Here, the upper wall 10a and the lower wall 10b are referred to as the outer wall 12a in the vehicle width direction.
and is formed thicker than the inner wall 12b. Therefore, unnecessary thickness of the center pillar 1 and the side sills 3 can be eliminated, the weight can be reduced, and rigidity can be ensured.

On the other hand, the center pillar 1 is provided with a joining flange 5 on the inner wall 9b side, and a groove 14 is formed on the front and rear walls 11a and llb to allow a flange 7a projecting from the earthen wall 10a on the side sill 3 side to pass through. .

Furthermore, the lower end 16 of the outer wall 9a of the center pillar 1 is provided to protrude downward and engage with the stepped portion 3a of the side sill 3.

Then, the center pillar 1 is attached to the earthen wall 10a of the side sill 3 by fitting the groove 14 of the center pillar 1 into the flange 7 of the side sill 3 and engaging the lower end 16 of the outer wall 9a with the step 3a of the side sill 3. Butt the joint flange 5 of the center pillar 1 to the flange 7a of the side sill 3.
The lower end 16 of the outer wall 9a of the center pillar 1 is attached to the side sill 3.
The two are joined by spot welding to the stepped portions 3a of the two. Therefore, the outer wall 9a of the center pillar 1 is connected to the earthen wall 10a of the side sill 3 via the lower end 16, and the inner wall 9b of the center pillar 1 is connected to the upper wall 10a of the side sill 3 via the flanges 5, 7, making it thicker. It has a structure in which parts are interconnected.

With this structure, when a load from the vertical direction acts on the side sill 3 as a bending load, the upper wall 10a
, also acts on the lower wall 10b as a bending load, and acts on the outer wall 12a and the inner wall 12b as a load in the direction of the road surface. Against such a load, the upper wall 10a and the lower wall 10
Since b is thick, it has sufficient strength, and
The flanges 7a and 7b function as ribs to ensure bending rigidity of the upper wall 10a and the lower wall 10b. The upper wall 10 protects the side sill 3 from collision loads from outside in the vehicle width direction.
a, the lower wall 10'b receives the load in the direction of the road surface and maintains sufficient strength. The side sills 3 ensure sufficient compression rigidity against loads in the longitudinal direction of the vehicle body, prevent the cabin from collapsing, and promote load transmission. Further, since the upper wall 10a and the lower wall 10b have high rigidity, they can sufficiently withstand the twisting of the side sill 3.

On the other hand, the center pillar 1 receives human power from the rear door attached to it. For example, when the rear door is opened, this input acts as a force that bends the center pillar 1 outward in the vehicle width direction diagonally backward, etc., but the outer wall 9a,
Since the inner wall 9b is thick, it has sufficient bending rigidity. In addition, a collision load from the outside in the vehicle width direction acts as a bending force on the center pillar 1, but even at this time, it has sufficient rigidity due to the thick outer wall 9a and inner wall 9b.

Furthermore, the center pillar 1 and the side sills 3 have sufficient rigidity against the above-mentioned loads and do not easily deform, so that the bonding strength between the two is extremely high. for example,
When a bending load is applied to the center pillar 1 from the outside in the vehicle width direction, the lower end 1
6, a force acts on the upper wall 10a of the side sill 3 to pull it upward, and a force acts on the inner wall 9b to push it, but the earth wall 10a, which is also thicker and more rigid, absorbs these loads. It securely holds the bridge, does not deform easily, and has extremely high joint rigidity.

4 to 10 show other embodiments. Components that are the same as those in the above embodiment are given the same reference numerals and redundant explanations will be omitted.

FIG. 4 shows the second embodiment. In this embodiment, when the side sill 3 is extruded, a partition portion 13 is integrally provided within the cross section to form two closed cross sections, thereby further increasing the rigidity. It is something.

FIG. 5 shows a third embodiment, in which a partition portion 18a and a diagonal partition portion 18b are provided in the side sill 3 to improve the moment of inertia and further increase the rigidity. Further, the diagonal partition portion 18 allows force to be transmitted to the thickest portion.

6 to 9 relate to a fourth embodiment, in which the lower part of the center pillar 1 is inserted into the side sill 3. That is, the upper wall 10a of the side sill 3
An opening 20 for inserting the center pillar 1 is provided in the opening 20, and the lower part of the center pillar 1 is inserted through this opening 20, and its lower end is in contact with the lower wall 10b of the side sill 3. The center pillar 1 is the upper wall 10 of the side sill 3.
For example, the entire circumference of the upper surface a and the upper surface of the stepped portion 3a is welded. Therefore, also in this embodiment, the center pillar 1 and the side sills 3 have thick outer walls 9a and 9b.
and the upper wall 10a are mutually bonded, and the bonding strength is extremely high.

10 and 11 show a fifth embodiment that is a modification of the fourth embodiment, and in this embodiment, the lower wall of the side sill 3],
Ribs 17a are each paired with Ob.

17b, and the lower part of the center pillar inserted into the side sill 3 is fitted into the ribs 17a and 17b on the thicker outer wall 9a and inner wall 9b. Therefore, the ribs 17a, 17 prevent the center pillar 1 from falling.
It is also reliably supported by the lower wall 10b via b, further improving the bonding strength.

FIG. 12 shows a method for achieving both vehicle body rigidity and weight reduction by thickening portions of the frame members that have a large contribution to vehicle body rigidity.

This method must be able to ensure the required rigidity and achieve sufficient weight reduction.

The range in which weight reduction and rigidity should be considered is determined as the entire vehicle body or a portion thereof, such as the joint between the center pillar and the side sill. The parts that exist within this defined area consist of a plurality of plate parts, such as the outer side of the vehicle body, the inner side, the front side, and the rear side. Therefore, there are many plate thicknesses in this range that must be considered, and the plate thicknesses can be determined, for example, by tl.
+t2...t. shall be. In order to replace steel plates with aluminum materials for each part, first the thickness of all plates is increased by 1.4 times in order to equalize the out-of-plane rigidity of each frame member (
Step Sl).

This value was calculated from the fact that the Young's modulus of iron and aluminum and the bending rigidity of the member are proportional to the cube of the plate thickness.

Next, in step S2, select parts that have a large contribution to the stiffness in the range considered, and group t, α-
α. Double it. Then, a plate thickness having a small contribution to stiffness is selected as group t. This group t is the group t
It may be the one that remains after choosing 1, or it may be one that is further selected from among the rest. Let this tl be β-β0 times. After changing each plate thickness in this way, the required stiffness S=S (tl, 2, -t-) in the considered range is calculated, and in step S4 this calculated stiffness S is calculated as required. Rigidity S. If it is determined that the weight is larger than WsmW, the process proceeds to step S5 and the weight of the range under consideration
(t, + t2+...1.) and target weight W. If it is smaller, end the step.

If the stiffness S is smaller than the target stiffness So in step S4, α is replaced with α8 in step S6, and the steps are repeated in the same manner.

Further, in step S5, the weight W or the target weight W is determined.

If it is larger than , β is replaced with βK in step S7, and the same steps are repeated. The step ends when both rigidity and weight reduction are achieved in this way. Therefore, it is possible to increase the rigidity by increasing the thickness of some of the car body frame members, such as the center pillar, or by increasing the thickness of the entire plate of a specific frame member within the entire car body.
The thicknesses of the center pillar 1 and side sills 3, which can achieve both weight reduction and rigidity by making other parts thinner, are also determined using this method.

[Effects of the Invention] As is clear from the above, according to the configuration of this invention, the frame members of the vehicle body can be molded from light metal, and the molding is extremely easy by extrusion molding or the like. In addition, it is extremely easy to change the thickness of parts of the plate, and by making the parts of the frame that contribute more to the rigidity of the car body thicker and connecting them to each other at these thicker parts, the strength of the joint can be improved. It is also easy to reduce the weight.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the main parts of the first embodiment of this invention;
Figure 3 is a perspective view of the entire vehicle body, Figure 4 is a sectional view of the second embodiment, Figure 5 is a sectional view of the third embodiment, and Figure 6 is the fourth embodiment. 7 is a sectional view of the same, FIG. 8 is a sectional view of the side sill, FIG. 9 is a sectional view of the center pillar, FIG. 10 is a perspective view of the fifth embodiment, and FIG. 11 is a sectional view of the same. is a sectional view of the same, and FIG. 12 is a flowchart showing a method of determining plate thickness. 1... Center pillar (skeletal member of the car body) 3... Side sill (skeletal member of the car body) 9a... Outer wall (part that contributes to the car body rigidity) 9b... Inner wall (part that makes a large contribution to the car body rigidity) (Large portion) 10a...Top wall (part that makes a large contribution to vehicle body rigidity) 10b...Bottom wall (part that makes a large contribution to vehicle body rigidity) Agent: Patent attorney Hidekazu Miyoshi Figure 2, Figure 3, Figure 1... - Center wing (skeletal member of the car body) 3... - Side door (skeletal member of the car body) 9a... Outer wall (portion that makes a large contribution to the rigidity of the car body) 9b... Inside! ! (Part that makes a large contribution to the car body rigidity) 10g - Upper wall (a part that makes a large contribution to the car body rigidity) 10b - Lower wall (a part that makes a large contribution to the car body rigidity) Fig. 1 Fig. 5 Fig. 8

Claims (1)

[Claims] A car body structure characterized in that frame members of a car body that are connected to each other are formed of light metal, parts of the frame members that have a large contribution to the rigidity of the car body are made thick, and the parts are connected to each other at the thickened parts.