JP2003011845A - Body construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a body construction provided with an underfloor structure part capable of reinforcing coupling rigidity of a fastening part between member and a body cross member without causing weight or cost increase. SOLUTION: The body construction is provided with the underfloor structure body having body cross members 6 plurally mounted on a chassis frame 3 of a ladder structure extended in a vehicular fore and aft direction X with intervals in the vehicular fore and aft direction X and an under floor structure part 8 with cross sectionally hat shaped members 9 mutually coupling longitudinal body cross members 6. It is characterized by that a length (a) of a hat shaped cross section flange part 902 of a member 9 is gradually reduced as it approaches a fastening part J in a neighborhood E of the fastening part J between the member 9 and the body cross member 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body structure in which an underfloor structure portion is connected to a chassis frame having a ladder structure, and in particular, a plurality of body cross members mounted on the chassis frame in the vehicle front-rear direction. Relates to a vehicle body structure in which a plurality of members are connected to each other to maintain the rigidity of an underfloor structure portion.

[0002]

2. Description of the Related Art As a vehicle body structure of a minibus, a truck, or the like, a chassis frame having a ladder structure extending in the vehicle front-rear direction is used to ensure the rigidity of the entire vehicle body. In a vehicle body structure employing this chassis frame, an axle side is attached to a lower portion of the chassis frame via a suspension, and a body side structure such as a cab, a cabin and a luggage box is attached to an upper portion thereof. For example, the body of the microbus has a cabin-like shape, and the underfloor structure portion of the body is mounted on the chassis frame and a plurality of body cross members arranged at a plurality of intervals in the vehicle front-rear direction,
It is composed of a plurality of straight members that connect the front and rear body cross members to each other, and a floor member that is placed and joined on the entire members.

Such an underfloor structure portion of the body strengthens the lower rigidity of the body, and receives a load of occupants and loads, a seat load from a plurality of seats for passengers attached to the floor surface, and the like. It is necessary to secure sufficient rigidity for various loads applied to the. Normally, FIG. 8 (a)
As shown in Figure 1, a body cross member 1 with an inverted hat cross section
A member 120 having a hat-shaped cross section is abutted against the web portion 110 of No. 00, and a floor material (not shown) is joined thereto to form an underfloor structure portion of the body. Here, the member 1 is attached to the flange 130 of the body cross member 100.
The end of the upward facing wall 140 of 20 is welded and the member 120
End flange 150 is welded to the web portion 110 of the body cross member 100 at a plurality of welding points W1.

By the way, the underfloor structure shown in FIG. 8 (a) vibrates up and down under the influence of various loads such as seat load and road surface reaction force while the vehicle is running. In particular, in the body cross members 100 arranged in parallel along the vehicle front-rear direction X, the front and rear body cross members 100 tend to mutually undergo torsional displacement (see symbols F1 and F2 in FIG. 1). As described above, when the front and rear body cross members 100 are twisted and displaced F1 and F2, resulting in a difference in height position, a large load is applied to the fastening portion J1 with the straight member 120 connecting the front and rear members. Therefore, the necessity of strengthening the joint rigidity of the fastening portion J1 increases.

In this case, the end flange 1 of the member 120
50 is welded to the web portion 110 of the body cross member 100 at least at two upper and lower welding points W1, and the larger the distance L1 between these welding points W1 is, the stronger the joint rigidity of this portion is, so that the end flange It is desirable that the height dimension of 150 is large. However, the end flange 15
A height dimension of 0 is usually formed to approximate the height dimension of the web portion of the member. Therefore, simply increasing the height of the end flange 150 and the height of the web of the member results in an increase in weight and an increase in mounting space, which is not preferable.

Therefore, in order to increase the distance between the upper and lower two points in the welded portion between the end flange of the member and the web portion of the body cross member, as shown in FIG.
The end portion of the web portion 160 of 20b is connected to the central portion 16 of the height H0.
It is formed as the amplification section 160-2 having a height H1 larger than that of 0-1 or as shown in FIG.
End flange 150c with relatively large height H2 at the end
It has been proposed that the auxiliary brackets 170 with the above are overlapped and integrally joined, and that the auxiliary brackets 150c are welded to the web portion (see 110 of FIG. 8A) of a body cross member (not shown).

[0007]

However, when the amplifying portion 160-2 having the height H1 shown in FIG. 8B is provided, the central portion 160-1 of the member has a hat-shaped cross section having the flange 121. Despite this, the amplification section 160-2 has a downward U-shaped cross section because there is no flange 121, so that there is a relief cutout 180 at the boundary, and the cross-sectional shape suddenly changes and the cutout 180 becomes It exists as a portion where stress concentration is likely to occur. Further, when the auxiliary bracket 170 shown in FIG. 8C is provided, the auxiliary bracket 170, which is an additional component, is required, and the auxiliary bracket 170 is required.
A step of joining to the end of c is required, resulting in an increase in cost.

Based on the above-mentioned problems, the present invention provides a vehicle body structure including an underfloor structure part capable of strengthening the joint rigidity of a fastening part between a body cross member and a member without increasing weight and cost. With the goal.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 is mounted on a chassis frame of a ladder structure extending in the vehicle front-rear direction at intervals in the vehicle front-rear direction. In a vehicle body structure having an underfloor structure having a body cross member to be placed and a member having a cross-sectional hat shape that connects the front and rear body cross members to each other, in the hat-shaped cross-section flange length of the member, It is characterized in that it is gradually reduced in the vicinity of the fastening portion between the member and the body cross member as it approaches the fastening portion. In this way, the length of the hat-shaped cross-section flange portion does not change suddenly in the vicinity of the fastening portion between the member and the body cross member. Therefore, even if the member receives a relatively large load, stress concentration points occur near the fastening portion. As a result, it is possible to suppress the occurrence of a bent portion, enhance the joint rigidity of the fastening portion between the body cross member and the member, and ensure the durability.

According to a second aspect of the present invention, in the vehicle body structure according to the first aspect, the height of the hat-shaped cross-section web portion of the member is gradually increased in the vicinity of the fastening portion as the portion approaches the fastening portion. Characterize. As described above, since the length of the hat-shaped cross-section flange portion and the height of the web portion of the member do not change suddenly in the vicinity of the fastening portion between the member and the body cross member, it is possible to suppress the occurrence of stress concentration points near the fastening portion. In addition, the vertical distance between the welded portions of the web portion of the member and the web portion of the body cross member can be made relatively large, and the joint rigidity of the fastening portion between the body cross member and the member can be strengthened and durability can be improved. Can be secured.

Preferably, the end of the web portion of the member is bent to form the end flange. In this case, the end portion of the web portion can be joined to the web portion of the body cross member through the end flange.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a microbus 1 adopting a vehicle body structure as an embodiment of the present invention. This microbus 1 is a cabin-shaped body 2 that forms the outer shell.
Equipped with. The body 2 is placed on a ladder-type chassis frame 3 and is integrally coupled thereto, and an axle (not shown) for pivotally supporting wheels is attached to a lower portion of the chassis frame 3 via a suspension (not shown). The chassis frame 3 is a substantially ladder type by integrally combining a pair of left and right side rails 4 having a substantially U-shaped cross-section extending in the vehicle front-rear direction X and a plurality of cross members 5 extending in the vehicle width direction Y. Has been formed.

As shown in FIG. 4, each of the left and right side rails 4 basically covers the entire area in the vehicle front-rear direction X and the inside of the web portion 401 forming a vertical plate and the upper and lower ends thereof in the vehicle width direction Y (in FIG. 4). Upper and lower flange portions 402, 4 extending to the left side)
It is formed so as to form a substantially U-shaped cross section. On each of the left and right side rails 4, a plurality of body cross members 6 on the body 2 side, which will be described later, are mounted at predetermined intervals along the vehicle front-rear direction X (see FIG. 1). L-shaped brackets 7 are provided at the joints to the 4's, respectively.

The L-shaped bracket 7 has a vertical portion 701.
Are welded to the outer surface (the right side in FIG. 4) in the vehicle width direction Y of the web portion 401 of each side rail 4, and the body portion is mounted on the mounting portion 702 that is bent from the upper end of the vertical portion 701 and extends outward in the vehicle width direction Y. The cross member 6 is placed. Body cross member 6
The fastening bolts 10 are inserted into the through holes n of the mounting portion 702, and the fastening bolts 10 can be fastened and coupled to each other. As shown in FIG. 1, the body 2 of the microbus 1 includes a front and rear mask 201 (only the front portion is shown) having front and rear windows, and left and right side wall portions 202 (left and right side wall portions) having left and right windows and an entrance / exit. (Only shown) and the upper roof 20
3 and the underfloor structure 8 on the lower side, and the whole is formed into a box-shaped cabin.

The underfloor structure portion 8 is formed so as to ensure the rigidity of the lower portion of the body 2. Moreover, the floor surface F (see FIG. 2) receives the occupant, load, and seat load of the passenger compartment, and the road surface reacts from below. It is formed so as to retain sufficient rigidity by receiving a force. The underfloor structure portion 8 is, as shown in FIGS.
A plurality of body cross members 6 mounted on the chassis frame 3 and arranged at predetermined intervals in the vehicle front-rear direction X; and a plurality of straight members 9 integrally connecting the front and rear body cross members 6 at appropriate places, It is composed of a body cross member 6 and a floor member 11 which is superposed on each upward surface f of the straight member 9 and welded to each other.

Of the floor surface F of the underfloor structure portion 8, a plurality of seats S (FIG.
(See) is installed. That is, each seat S has its leg s
A floor mounting portion s1 is formed at 0, and the floor mounting portion s1 is placed on a plurality of linear members 9 via a floor material 11 and fastened and coupled to each other by bolts B or the like. Therefore, it is necessary that the member 9 is connected to the body cross member 6 and the floor member 11 and has sufficient rigidity against a seat load. As shown in FIGS. 2, 3, and 4, the body cross member 6 is formed in an inverted hat-shaped cross-sectional shape, and the tightening bolt 1 is placed at an appropriate position on the bottom wall 601 forming the main part.
0 (see FIG. 4) is formed with a through hole n, and the bottom wall 6
A front and rear flange 603 is further formed to extend from the upper ends of the front and rear web portions 602 that are bent and extended from 01. The body cross member 6 has a closed cross-section structure at the overlapping portion by the floor material 11 being joined to each upward surface f of the front and rear flanges 603, so that the rigidity can be enhanced.

As shown in FIGS. 2 and 3, each member 9 is a straight member provided in the vehicle front-rear direction X, and its front and rear ends are integrally joined to the front and rear body cross members 6 so that the front and rear members are integrally joined. A fastening portion J with the body cross member 6 is formed at the end. The cross-sectional shape of this member 9 is different in the vicinity area E of the front and rear fastening portions J and the intermediate area C between them. The middle region C of the member 9 has the same hat-shaped cross section (see FIG. 3) and is formed so as to continuously maintain the same height h of the web portion 901 and the same length a of the same left and right flange portions 902. To be done. The floor mounting portion s1 of the leg of the seat S is placed on the upper wall 903 of the intermediate region C of the member 9 via the floor material 11 and bolted.

As shown in FIGS. 3 and 5 (a), the length a of the left and right flange portions 902 gradually decreases toward the fastening portion J, and the length in the protruding direction is zero immediately before the fastening portion J. Therefore, the sudden change portion of the flange portion 902 is eliminated. Further, as shown in FIG. 3 and FIG. 5B, in the side view of the member 9, the height h of the left and right web portions 901 gradually increases as approaching the fastening portion J, and the maximum height immediately before the fastening portion J is reached. The height becomes hm, and the sudden change in height of the web portion 901 is eliminated. Here, the web portion 9 of the member 9
01 is bent at the fastening portion J to extend and form the end flange 12 having a dimension close to the maximum height hm.

Here, the height of the end flange 12 is formed so as to be a value close to the height of the web portion 602 of the body cross member 6, and the end flange 12 has two upper and lower portions.
It is welded to the web portion 602 at some point. In this case, up and down 2
The distance Lw between the welding points W at the points is the web portion 901 in the intermediate region C.
A value exceeding the height h can be secured, the distance Lw between the two welding points W can be increased, and the joint rigidity of the fastening portion J is strengthened. Although the end flange 12 and the web portion 602 of the body cross member 6 are welded to each other at upper and lower portions here, in some cases, the welding points W may be provided at three or more upper and lower portions. ,
The joint rigidity of the fastening portion J, which is a welded portion, is further enhanced.

In the microbus 1 having the vehicle body structure having the underfloor structure portion 8 as described above, the floor surface F vibrates under the influence of a load, particularly a seat load from each seat S and a road surface reaction force during traveling. At this time, the seat load is the floor material 11
The load is distributed to the member 9 joined to the body 9 and the body cross members 6 connected before and after the member, and the rigidity of the underfloor structure portion 8 is secured by this load distribution structure. Particularly, regarding the body cross members 6 arranged in parallel along the vehicle front-rear direction X, the front and rear body cross members 6 are torsionally displaced relative to each other (reference numerals F1 and F in FIGS.
2), but because the joint rigidity of the fastening portion J between each member 9 and the front and rear body cross members 6 is set to be relatively large, the torsional displacement of the front and rear body cross members 6 is suppressed, and the body displacement is suppressed. The durability of is sufficiently secured.

In this case, in the intermediate region C of the member 9, the height h of the web portion 901 is relatively small, and the length a of the flange portion 902 is relatively large and is formed so as to continuously project. The overall weight and rigidity can be improved. Moreover, since the member 9 gradually decreases the length a of the flange portion 902 in the projecting direction and the height h of the web portion 901 in the vicinity region E before and after the member 9 in the vicinity region E of the fastening portion J, The cross-sectional shape does not change suddenly, that is, the cross-section coefficient does not change suddenly, stress concentration points can be prevented from occurring, bending deformation sections can be prevented from occurring in the area E in the vicinity of the fastening section J, and durability can be ensured.

Further, the height of the end flange 12 is formed to be a relatively large value that exceeds the height h of the web portion 901 in the intermediate region C, and the end flange 12 and the web portion 602 of the body cross member 6 are formed. A relatively large vertical distance Lw between the welding points W can be adopted, and the joint rigidity of the fastening portion J between the member 9 and the body cross member 6 can be further strengthened. At this time, since no special parts are added, it is possible to avoid an increase in the number of parts and an increase in cost. Moreover, it is possible to prevent deterioration of the dimensional system due to addition of special parts and occurrence of quality variations.

Further, in the member 9 of FIGS. 5A and 5B, the length a of the flange portion 902 is gradually reduced in the vicinity of the fastening portion J, and the height dimension of the web portion 901 is gradually increased by that amount. Therefore, the shape of the material P before press forming, which is the expanded shape of the member 9, becomes substantially rectangular as shown in FIG. Therefore, as the material P used when manufacturing the member 9, a rectangular material with a high material yield can be used, and in this respect, further cost reduction can be achieved.

In the above description, the member 9 used in the vehicle body structure having the underfloor structure portion 8 has the height h of the hat-shaped cross-section web portion in the intermediate region C is higher than the height of the web portion 602 of the body cross member 6. By setting it small, the weight of the member 9 was reduced. However, when it is not necessary to reduce the weight, as shown in FIG. 7, the height hd of the web portion 901d of the member 9d having the hat-shaped cross section is kept constant, and the height hd of the web portion 901d and the body hd are equal to each other. The height of the web portion 602d of the cross member 6 is set to an approximate value, and only the length a in the protruding direction of the left and right flange portions 902d is determined by the fastening portion J.
It may be formed such that the length a in the protruding direction becomes zero immediately before the fastening portion J, as it approaches 0. In this case as well, the length a in the protruding direction of the flange portion 902d is gradually reduced, so that even if the vicinity E of the fastening portion J receives a load, the hat-shaped cross-sectional shape does not change suddenly, and the occurrence of stress concentration points can be prevented, Bending deformation can be prevented from occurring in the region near the fastening portion J, and durability can be ensured.

Although the vehicle has been described as the microbus 1 in the above description, the configuration is not limited to this, and the vehicle body structure including the underfloor structure portion 8 mounted on the chassis frame 3 is adopted. The above-mentioned vehicle can be used, and similar effects can be obtained in those cases.

[0026]

As described above, according to the invention of claim 1, since the length of the hat-shaped cross-section flange portion does not suddenly change in the vicinity of the fastening portion between the member and the body cross member, the member has a relatively large load. Even if it receives a stress, it is possible to suppress the occurrence of bending parts due to stress concentration points near the fastening part,
The joint rigidity of the fastening portion between the body cross member and the member can be enhanced, and durability can be secured.

According to the second aspect of the present invention, since the length of the hat-shaped cross-section flange portion and the height of the web portion of the member do not change suddenly in the vicinity of the fastening portion between the member and the body cross member, a stress concentration point near the fastening portion. Can be suppressed, and the vertical distance between the welds of the member web portion and the body cross member web can be made relatively large, and the joint rigidity of the fastening portion between the body cross member and the member can be increased. It can be strengthened and its durability can be secured.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a body and chassis frame of a microbus adopting a vehicle body structure including an underfloor structure portion according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a notched main part of an underfloor structure portion of the microbus of FIG.

3 is an enlarged perspective view of a body cross member and a member fastening portion of the underfloor structure portion of the microbus of FIG.

FIG. 4 is an enlarged perspective view of the chassis frame and body cross member of the underfloor structure portion of the microbus of FIG. 1 before connection.

5A and 5B show members used in the underfloor structure portion of the microbus of FIG. 1, in which FIG. 5A is a cutout enlarged plan view and FIG. 5B is a cutout enlarged side view.

FIG. 6 is a developed state view of a material of a member used in the underfloor structure portion of the microbus of FIG. 1.

7A and 7B are views showing a combined state of a member and a body cross member used in another embodiment of the present invention, FIG. 7A is a schematic front view, and FIG. 7B is a schematic plan view.

FIG. 8 is a view showing a joined state of a member and a body cross member used in a vehicle body structure including a conventional underfloor structure portion, (a)
Is a schematic cut-away perspective view of the first conventional example, FIG. 9B is a schematic cut-away perspective view of the second conventional example, and FIG.

[Explanation of symbols]

1 microbus 3 chassis frame 6 body cross members 8 Underfloor structure section 9 members 901 Web part 902 flange a Flange length E Near the fastening part J fastening department X vehicle front-back direction

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[Procedure amendment]

[Submission date] July 3, 2001 (2001.7.3)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinichi Mochizuki             5-33, Shiba, Minato-ku, Tokyo, Mitsubishi Motors             Industry Co., Ltd. (72) Inventor Kiyotaka Sakakibara             16/3, 580 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa             Within Ryo Automotive Engineering Co., Ltd. F term (reference) 3D003 AA01 BB09 BB10 CA18 DA02                       DA19

Claims (2)

[Claims] 1. A cross section for connecting a plurality of body cross members mounted on a chassis frame having a ladder structure extending in the vehicle front-rear direction at intervals in the vehicle front-rear direction, and front and rear body cross members. In a vehicle body structure including an underfloor structure portion having a hat-shaped member, the hat-shaped cross-section flange length of the member is gradually increased in the vicinity of the fastening portion between the member and the body cross member as the fastening portion approaches the fastening portion. A body structure characterized by a reduction. 2. The vehicle body structure according to claim 1, wherein the height of the hat-shaped cross-section web portion of the member is gradually increased in the vicinity of the fastening portion as the portion approaches the fastening portion. .