JP2001080361A - Back door structure for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a back door structure over a wide range so as to omit a conventional lean reinforcement by using a tailored blank material formed by connecting a thick upper part and a thin lower part together as a component of the back door. SOLUTION: A hatchback type back door opening/closing a cargo room opening arranged in the back part of an automobile is formed by connecting an inner panel and an outer panel 4 constituting the inside face on the interior side and the outside face together in the closed cross section shape. In this case, the inner panel 4 is constructed of a tailored blank material 4' formed by connecting a relatively thick upper part 4a and a thin lower part 4b together. The height Hw of a back door wind shield 6 and an interval hw between the boundary line L between the upper and lower side parts 4a, 4b and the upper side part of the back door wind shield 6 are set so as to satisfy the following relationship: hw<=Hw/2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a back door structure for an automobile.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show a conventional back door 20 provided at the rear of an automobile. As shown in FIGS. 7 and 8, the back door 20 is formed by connecting a door inner panel 21 forming an inner surface on the vehicle interior side and a door outer panel 22 forming an outer surface on the vehicle exterior side into a closed sectional shape. It is an automobile part, and an opening 23 for a back door window is provided in an upper part. The door inner panel 21 and the door outer panel 22 are press-formed products formed by pressing a steel plate having a uniform thickness.
Then, as shown in FIG.
The back door hinges 24a and 24b that rotatably support the back door 20 are attached to the left and right sides (upper left and right corners) of the upper end edge of the top door 1.

In order to partially reinforce a predetermined portion of the back door 20, that is, a mounting portion of the back door hinges 24a, 24b, reinforcements 25a, 25b are provided between the door inner panel 21 and the door outer panel 22.
Are attached (see FIG. 8). In addition, reinforcement 25a to a back door hinge attachment part,
The attachment of the reinforcement 25b is usually performed by means of welding.
The back door 20 against the load at the time of opening and closing the back door at b
Has been reinforced.

[0004]

However, in the above-described conventional back door structure, if the reinforcements 25a and 25b are not plates having a certain thickness or more, the reinforcements 25a and 25b are welded. In reality, it cannot be attached to the back door 20. For this reason, even if it is more effective to reinforce a wide area with a thin plate material, effective reinforcement must be performed only by using reinforcements 25a and 25b having a certain thickness or more. There was something I could not do.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a sheet material having an appropriate thickness so that reinforcement can be performed over a wide range, and a lean material which has been conventionally used can be provided. It is an object of the present invention to provide a back door structure of a vehicle that can omit a force.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, according to the present invention, there is provided a tailored joint comprising an upper portion having a relatively large thickness and a lower portion having a relatively small thickness. A blank material is provided as a constituent member of the back door. Further, in the present invention, the position of the boundary between the upper part and the lower part is set at a height corresponding to the arrangement area of the back door wind shield, and the height of the back door wind shield is set to H _W. and then, when the distance between the upper side portion of the position of the boundary line the back door windshield and h _W, is set such that h _W ≦ H _W / 2. In the present invention, the tailored blank material constitutes a door inner panel of a back door.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an automobile 1 having a back door structure according to an embodiment of the present invention. As shown in FIG. 1, an opening 2 for a luggage compartment is provided at the rear of the automobile 1, and the opening 2 is opened and closed by a flip-up (rotating) back door 3. . The back door 3 has an upper end attached to a vehicle body via a back door hinge (not shown), and is supported so as to be rotatable up and down around the back door hinge.

The above-described back door 3 is a member formed by connecting a back door inner panel 4 constituting an inner surface on the vehicle interior side and a back door outer panel 5 constituting an outer surface on the outside of the vehicle in a closed sectional shape. FIG. 2 shows a back door inner panel 4 used in the present embodiment. The back door inner panel 4 has a relatively thick upper portion 4a and a relatively thin lower portion 4a. As shown in FIG. 3, the portion 4b is made of a tailored blank material 4 'which is brought into contact with the portion 4b and joined (butt-welded) to each other by laser or the like. In this case, the upper part 4
thickness of a is t _1, the thickness of the lower portion 4b are selected respectively to t _2, are set such that t _1> t _2.

In the present embodiment, the upper portion 4a having a relatively large thickness and the lower portion 4 having a relatively small thickness are provided.
The boundary line L with b (see FIG. 2) is set as follows. That is, the position of the boundary line L between the upper part 4a and the lower part 4b of the back door inner panel 4 is set at a height corresponding to the area where the back door windshield 6 is provided. Furthermore, backdoor windshield 6
Is defined as H _W, and the distance between the position of the boundary line L and the upper side 6a of the back door windshield 6 is defined as h _W (see FIG. 2), so that h _W ≦ H _W / 2. It is set as follows.

Thus, the back door windshield 6
By making the plate thickness of the region α above the half height portion relatively thicker than the region β below it, the door panel 3 is reinforced by the tailored blank material 4 ′. I have.

A comparative experiment was conducted to confirm the reinforcing effect when the tailored blank material 4 'was used as the back door inner panel 4, and the following results were obtained. At the time of the experiment, the combination of the back door inner panel 21 (see FIG. 4A) and the back door outer panel (not shown), which are conventionally used, having a uniform plate thickness, is used as a conventional reinforcement 25.
a, 25b, a conventional backdoor 20 (see FIG. 8), a backdoor inner panel 4 (see FIG. 4 (b)) composed of a tailored blank 4 ', and a backdoor outer panel having a uniform plate thickness. The back door 3 according to the present embodiment (without using a reinforcement as in the related art) was prepared, and the weight of each was measured.

When the back door is opened, reaction forces F ₁ and F ₂ from a pair of right and left balancers 7 disposed at the rear of the vehicle body as shown in FIG.
(See FIG. 5) is applied as a load to these back doors 3 and 20, respectively.
20 were measured. At this time, the back doors 3 and 20 are changed from the basic state shown by the dashed line in FIG.

When the weight ratio and the deformation amount ratio were calculated from the above measurement results, the results shown in Table 1 below were obtained. In addition, the numerical value described in Table 1 is a numerical value when the case of the conventional backdoor reinforced by reinforcement is set to the reference value of 100.

[0015]

[Table 1]

As is apparent from Table 1, the case of the conventional backdoor 20 reinforced by the reinforcement 25a, 25b as in the conventional case and the case of the backdoor 3 reinforced by the tailored blank material 4 ' And
It was confirmed that the latter was reduced in both weight and deformation.

As described above, in the back door 3 of the present embodiment, the back door 3 is reinforced by using the tailored blank material 4 'as the back door inner panel 4 instead of using the reinforcements 25a and 25b. I do it. More specifically, by using the tailored blank material 4 ′, the thickness of the back door portion above the half height portion of the back door windshield 6 is made relatively thick, and the back door portion below it Is relatively thin, so that the back door hinge mounting portion (upper portion) of the back door 3 is reinforced. Therefore, the back door 3 of the present embodiment
According to the prior art, the reinforcement 25a,
The use of the tailored blank material 4 ′ makes it possible to adopt a reinforcing structure that could not be performed with the back door 20 using 25b, that is, a reinforcing structure in which a wide area is reinforced with a relatively thin plate thickness. It becomes possible. Along with this, it is possible to easily provide reinforcement over a wide range with the tailored blank material 4 'having an appropriate thickness.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment.
Various modifications and changes are possible based on the technical concept of the present invention. For example, in the above-described embodiment, the back door inner panel 4 is made of the tailored blank material 4 ′. However, the back door outer panel 5 can be made of the tailored blank material. Both the panel 4 and the back door outer panel 5 may be made of a tailored blank material.

[0019]

According to the first aspect of the present invention, there is provided a back door comprising a tailored blank material formed by joining an upper portion having a relatively large thickness and a lower portion having a relatively small thickness. Since it is used as a member, it is possible to reinforce the upper portion (backdoor hinge attachment portion) of the tailored blank material with an appropriate plate thickness over a wide range without using reinforcement. .
In addition, since the conventionally used reinforcement can be omitted, the operation of mounting the reinforcement can be omitted, and the number of parts and the number of working steps can be reduced.

According to a second aspect of the present invention, the position of the boundary between the upper part and the lower part of the tailored blank is set at a height corresponding to the area where the back door windshield is provided. If the height of the back door windshield is H _W and the distance between the position of the boundary line and the upper side of the back door wind shield is h _W , h
_Since it is set so that _W ≦ H _W / 2, the thickness of the portion above the half height portion of the back door windshield is made relatively thicker than the portion below it. The back door can be reinforced by adjusting the height position h _W appropriately according to the thickness of the upper part and the lower part of the tailored blank material. It is possible to provide a reinforcing structure that can be applied over a wide range and that requires relatively light weight.

According to the third aspect of the present invention, since the door inner panel of the back door is formed by the tailored blank material, the upper portion of the door inner panel to which the back door hinge is attached is attached to the door inner panel itself. Thus, it is possible to sufficiently secure the holding strength of the back door hinge at the back door hinge attachment portion of the door inner panel without using reinforcement as a separate member. Further, it is possible to reduce the weight of the door-back door as compared with a back using the reinforcement.

[Brief description of the drawings]

FIG. 1 is a perspective view of an automobile having a back door structure according to an embodiment of the present invention.

FIG. 2 is a perspective view of a back door inner panel made of a tailored blank material.

FIG. 3 is a perspective view showing an abutting portion of the tailored blank material and showing a butt portion between an upper portion and a lower portion of the back door inner panel.

FIG. 4A is a perspective view of a back door inner panel used in a conventional back door structure, and FIG. 4B is a perspective view of a back door inner panel used in a back door structure according to the present invention.

FIG. 5 is a perspective view showing a direction in which a load acts on the back door inner panel when a reaction force from a balancer acts on the back door as a load.

FIG. 6 is a side view showing a deformed state of the back door when a load is applied to the back door.

FIG. 7 is a cutaway perspective view of a conventional back door.

FIG. 8 is an exploded perspective view of a conventional back door.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automobile 3 Back door 4 Back door inner panel 4a Upper part 4b Lower part 4 'Tailored blank material 5 Back door outer panel 6 Back door windshield L Boundary line P Contact point (butting point)

Claims (3)

[Claims] 1. An automobile comprising a tailored blank member formed by joining a relatively thick upper portion and a relatively thin lower portion to each other as a constituent member of a back door. Back door structure. 2. A position of a boundary line between the upper part and the lower part is set at a height position corresponding to an area where a back door windshield is provided, and the height of the back door wind shield is H _W. The distance between the boundary line and the upper side of the back door windshield is defined as h _W , so that h _W ≦ H _W / 2. Car back door structure. 3. The back door inner panel is made of the tailored blank material.
Or a back door structure for an automobile according to 2.