JP7201490B2 - Body frame structure with underrun protector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body frame structure provided with an underrun protector for preventing one vehicle from running under another vehicle when vehicles collide.

For example, in order to prevent a passenger car from going under when it collides with a passenger car, a rush prevention device (generally, the front device is called a front underrun protector and the rear device is called a rear underrun protector) is installed at the front and rear of the truck. It is compulsory to wear a protector). For example, Patent Literature 1 discloses an underrun protector attached to a vehicle frame via a stay.

WO2018/038210

By the way, the strength test for underrun protectors has been strengthened due to the revision of the safety standards, and higher strength is required, including for the vehicle body frame structure where underrun protectors are installed. For example, in a strength test that stipulates the permissible amount of movement of a rear underrun protector when a predetermined load is applied, the revised load is twice as large as the conventional load. As for the body frame used in the test, a rigid body frame could be used in the past, but after the revision, it is required to evaluate the actual frame used in the actual vehicle.

Based on the content of the strength test after such revision, the present inventor conducted repeated studies and found that the deformation of the side frame greatly affects the amount of movement of the underrun protector when a load is applied. Found.

This point will be described with reference to FIGS. 4 to 7. FIG. FIG. 4 shows a conventional vehicle comprising a pair of side frames 12 spaced apart in the vehicle width direction, a pair of stays 13 attached to each side frame 12, and an underrun protector 14 attached to these stays 13. car body frame structure. FIG. 5(a) is a rear view showing the body frame structure from the rear in the longitudinal direction of the vehicle body, and FIG. 5(b) is a side view showing the structure from the outside in the vehicle width direction. Here, the side frame 12 is formed with a U-shaped cross section by a web 12a extending in the longitudinal direction of the vehicle body, and an upper flange 12b and a lower flange 12c extending in the vehicle width direction from the upper and lower ends of the web 12a. The stay 13 is attached to the side frame 12 by affixing the attachment portion 13c to the outer surface of the web 12a and fixing it with a bolt or the like.

In the strength test for such a vehicle body frame structure, a predetermined load L is applied to the underrun protector 14 at a position generally shown in FIG. When a load L is applied to the underrun protector 14, a bending moment corresponding to the length of the stay 13 acts on the side frame 12, so that the side frame 12 is bent downward. Here, the web 12a is a double plate in which the web 12a and the stay 13 are overlapped at an attachment portion 13c to which the stay 13 is attached, and is a single plate at other portions. The stiffness changes at the transition part of Therefore, the side frame 12 is bent downward starting from the portion where the rigidity changes, as indicated by the dashed line in FIG. 6(a).

In the strength test, as shown in FIG. 4, the load L is also applied to the end of the underrun protector 14 in the vehicle width direction, so that the side frame 12 is also bent inward in the vehicle width direction. Become. Here, FIG. 7(a) is a side view showing the periphery of the mounting portion 13c of the stay 13 from outside in the vehicle width direction, and FIG. 7(b) is a plan view showing the periphery of the mounting portion 13c from above. It is a diagram. As shown in FIG. 7(b), when the load L is applied to the end of the underrun protector 14, the side frame 12 is positioned at the middle side of the mounting portion 13c in the longitudinal direction of the vehicle body, as indicated by the dashed line in the drawing. Since the located inner end portion 13d moves inward in the vehicle width direction, the web 12a is bent inward in the vehicle width direction with the inner end portion 13d as a starting point. When the limit of resistance is exceeded, the web 12a is deformed, and this deformation triggers the downward bending of the side frame 12, so that the underrun protector 14 moves greatly in the direction in which the load is applied.

In addition, the above-mentioned Patent Document 1 aims to suppress the amount of movement of the underrun protector by reinforcing the stay, and does not suppress the amount of movement of the underrun protector caused by the deformation of the side frame. was still difficult to resolve.

An object of the present invention is to solve such problems, and an object thereof is to provide a vehicle body frame structure capable of suppressing an increase in the amount of movement of the underrun protector due to deformation of the side frame. do.

The present invention extends downward to a side frame having a U-shaped cross-section formed by a web extending in the longitudinal direction of the vehicle body and upper and lower flanges extending in the vehicle width direction from the upper and lower ends of the web. A vehicle body frame structure to which an underrun protector is attached via a stay, wherein the stay has an attachment portion attached to the web, and the attachment portion has an inner end located on the middle side in the longitudinal direction of the vehicle body. wherein a reinforcing plate positioned above the inner end is attached to the upper flange.

Preferably, the reinforcing plate is formed to have an L-shaped cross section by integrally connecting a horizontal plate portion along the upper flange and a vertical plate portion along the web.

According to the vehicle body frame structure of the present invention, since the strength of the side frame can be increased, the amount of movement of the underrun protector can be suppressed. In addition, since there is no need to change the specifications of the side frames significantly, it is possible to keep costs down by using existing molds. Furthermore, since the improvement of the strength of the side frame is limited to the portion to be reinforced, it is possible to minimize an increase in cost and mass.

1 is a side view of a truck to which one embodiment of a vehicle body frame structure according to the present invention is applied to the front and rear; FIG. 2(a) is a side view showing the vehicle body frame structure applied to the rear in FIG. 1 in more detail, and FIG. 2(b) is a side view showing it from outside in the vehicle width direction. is a perspective view from the inside of the. FIG. 10 is a diagram showing another means for fixing the reinforcing plate; FIG. 11 is a perspective view showing a conventional vehicle body frame structure; Fig. 5(a) is a rear view showing the conventional vehicle body frame structure in more detail, and Fig. 5(b) is a rear view shown from the rear in the longitudinal direction of the vehicle body; It is a side view. FIG. 6A is a side view showing a deformation state of a side frame when a strength test is performed on a conventional vehicle body frame structure, FIG. (b) is a side view seen from the inside in the vehicle width direction. FIG. 7A is a side view showing the deformation around the mounting portion of the stay when a strength test is performed on a conventional vehicle body frame structure, and FIG. , and FIG. 7(b) is a plan view from above.

An embodiment of a vehicle body frame structure according to the present invention will be described below with reference to the accompanying drawings. In addition, "upper", "lower", "front", "rear", "left", and "right" in this specification etc. refer to the direction of a person sitting in the driver's seat in a vehicle to which the body frame structure is applied. Say. In addition, the drawings preferentially show the parts necessary for explaining the present embodiment, and omit the parts for which the explanation is not particularly necessary.

FIG. 1 shows a vehicle 100 to which the body frame structure according to the invention is applied to the front and rear. In the following description, the vehicle body frame structure 1 provided at the rear will be described.

As shown in FIG. 2, the vehicle body frame structure 1 of the present embodiment includes a pair of side frames 2 that extend along the longitudinal direction of the vehicle body and are spaced apart in the vehicle width direction, and are attached to the respective side frames 2. It is provided with a pair of stays 3 , a rear underrun protector 4 (hereinafter simply referred to as “underrun protector 4 ”) extending in the vehicle width direction and attached to these stays 3 , and a reinforcing plate 5 .

The side frame 2 includes a web 2a extending along the longitudinal direction of the vehicle body, an upper flange 2b extending inward in the vehicle width direction from the upper end of the web 2a, and an inner portion extending in the vehicle width direction from the lower end of the web 2a. The web 2a, the upper flange 2b, and the lower flange 2c form a U-shaped cross section. As shown in the figure, the web 2a of this embodiment has its upper and lower ends extending substantially horizontally from the front to the rear. 2c also extends substantially horizontally from the front to the rear.

The stay 3 includes a U-shaped stay main body 3a in cross section that is wide at the top and narrows downward, and a mounting plate 3b provided at the rear end of the main stay 3a. The stay 3 of this embodiment is attached to the side frame 2 by fixing the upper end portion of the stay body portion 3a to the outer surface of the web 2a in the vehicle width direction with bolts and nuts. The upper end portion of the stay body portion 3a fixed to the web 2a is referred to as a mounting portion 3c, and the end portion of the mounting portion 3c located on the middle side in the longitudinal direction of the vehicle body is referred to as an inner end portion 3d.

The underrun protector 4 is formed to have a hollow rectangular shape, and is attached so as to bridge the pair of stays 3, like the conventional one shown in FIG. As shown in FIG. 2(a), the underrun protector 4 in this embodiment is configured to be fixed to the mounting plate portion 3b with bolts and nuts.

The reinforcing plate 5 integrally connects a horizontal plate portion 5a extending horizontally along the longitudinal direction of the vehicle body and a vertical plate portion 5b extending horizontally along the longitudinal direction of the vehicle body. It is formed to have an L-shaped cross section. As shown in FIG. 2, the reinforcing plate 5 is arranged so that the horizontal plate portion 5a overlaps the lower surface of the upper flange 2b from the inside in the vehicle width direction, and the vertical plate portion 5b is placed on the inner surface of the web 2a in the vehicle width direction. It is attached to the side frame 2 so as to overlap. In this embodiment, rivets are used to fix the horizontal plate portion 5a to the upper flange 2b and the vertical plate portion 5b to the web 2a. As for the position in the longitudinal direction of the vehicle body when the reinforcing plate 5 is attached to the side frame 2, as shown in FIG. I'm about to.

In such a vehicle body frame structure 1, the reinforcing plate 5 can increase the strength of the periphery of the side frame 2 where the inner end portion 3d is located. Here, the web 2a is a double plate in the portion where the web 2a and the mounting portion 3c overlap, and is a single plate in other portions. stiffness will change. Therefore, when the vehicle body frame structure 1 is subjected to a strength test similar to that of the conventional vehicle body frame structure shown in FIG. However, since the bending is suppressed by the reinforcing plate 5, the forward movement amount of the underrun protector 14 can be suppressed.

Further, when a predetermined load L is applied to the underrun protector 4 as shown in FIG. 4, the side frame 2, as described with reference to FIG. As a starting point, it also receives a force that causes it to bend inward in the vehicle width direction. On the other hand, in the present embodiment, the reinforcement plate 5 increases the strength of the periphery of the side frame 2 where the inner end 3d is located, so that such inward bending in the vehicle width direction is also suppressed. be able to. Therefore, the downward bending of the side frames 12 due to the inward bending in the vehicle width direction, which has been regarded as a problem in the conventional vehicle body frame structure, is also suppressed, so the amount of movement of the underrun protector 14 is suppressed. be able to.

In addition, in the vehicle body frame structure 1 of the present embodiment, while the reinforcement plate 5 is added, the specification of the side frame 2 does not change significantly from that of the conventional one. can. Further, since the strength of the side frame 2 is improved only in the portion to be reinforced by the reinforcing plate 5, the increase in cost and mass can be minimized.

Although one embodiment of the vehicle body frame structure according to the present invention has been described above, this embodiment is merely an example, and the present invention includes various modifications within the scope of the claims.

For example, in the above-described embodiment, the reinforcing plate 5 was fixed to the side frame 2 by rivets, but as shown in FIG. 3, it may be fixed using bolts and nuts, or fixed by welding. good too. Further, although the reinforcing plate 5 described above is formed to have an L-shaped cross section by the horizontal plate portion 5a and the vertical plate portion 5b, it may be formed by only the horizontal plate portion 5a. Moreover, you may reinforce only by the vertical board part 5b. Furthermore, the reinforcing plate 5 is not limited to being attached to the side frame 2 from the inside in the vehicle width direction as described above, and may be attached from the outside in the vehicle width direction.

1: Body frame structure 2: Side frame 2a: Web 2b: Upper flange 2c: Lower flange 3: Stay 3a: Stay body 3b: Mounting plate 3c: Mounting 3d: Inner end 4: Underrun protector (rear under lamp protector)
5: Reinforcement plate 5a: Horizontal plate portion 5b: Vertical plate portion 100: Vehicle

Claims (2)

A web along the longitudinal direction of the vehicle body, and a side frame formed with a U-shaped cross section by an upper flange and a lower flange extending in the vehicle width direction from the upper end and lower end of the web, respectively, via a stay extending downward. A vehicle body frame structure to which an underrun protector is attached,
The stay has a mounting portion that is mounted on the web, and the mounting portion has an inner end that is located on the middle side in the longitudinal direction of the vehicle body,
A vehicle body frame structure having an underrun protector, wherein a reinforcing plate positioned above the inner end is attached to the upper flange. 2. The underrun according to claim 1, wherein the reinforcing plate is formed to have an L-shaped cross section by integrally connecting a horizontal plate portion along the upper flange and a vertical plate portion along the web. A body frame structure with a protector.

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