Underrun protector structure

Abstract

To propose an underrun protector structure which can increase a static peak load occurring during an offset collision without increasing the number of components and the weight.SOLUTION: In an underrun protector structure 1, an underrun protector body 10 is attached to a vehicle body frame 2 through a stay 3 extending downward. The underrun protector body 10 extends in a vehicle width direction and forms a square tube shape. At least a part, which is located at the outer side as seen in the vehicle width direction relative to the stay 3, of an upper surface of the underrun protector body 10 is an inclined surface which inclines so as to lower from the outer side to the inner side in a vehicle body fore and aft direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an underrun protector structure for preventing one vehicle from sliding under another vehicle when the vehicles collide. [Background technology]

[0002] In order to prevent a passenger car or the like from sliding underneath in the event of a collision, large vehicles such as trucks are fitted with an intrusion prevention device (underrun protector) attached to the body frame via a stay (bracket) or the like (see, for example, Patent Document 1). Underrun protectors are subject to legal strength requirements, and their performance is evaluated by confirming the static peak load measured by pressing a pressure probe horizontally against the underrun protector body, which extends in the vehicle width direction.

[0003] In the evaluation of static peak loads, in a test assuming an offset collision, as shown in FIG. 6, a load is applied from the outside in the longitudinal direction of the vehicle body by a pressure element P to a portion of the underrun protector main body 110 that is located outside in the vehicle width direction from the portion where the underrun protector main body 110 is attached to the stay 103, and performance is evaluated based on the relationship between the stroke amount of the pressure element P at that time and the magnitude of the load. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-255050 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-052897 Summary of the Invention [Problem to be solved by the invention]

[0005] If the ends of the underrun protector main body are crushed during an offset collision, the load-bearing capacity of the underrun protector will be significantly impaired, resulting in a problem of a reduction in the static peak load of the underrun protector. In particular, when an underrun protector main body 110 is used that is a square tube with a rectangular cross section over its entire length in the vehicle width direction, as shown in Figure 6, the ends tend to be deformed and crushed when a load is applied by the pressure tool P.

[0006] A conventional technique for improving the strength of underrun protectors is to place a crush prevention body made of an extruded aluminum alloy or a resin material inside the end of the rectangular cylindrical underrun protector body (see, for example, Patent Document 2). However, this technique has the problem that adding a crush prevention body increases the number of parts, which in turn leads to increased weight and costs.

[0007] Furthermore, in the evaluation of static peak loads, the pressure element is set to press perpendicularly against the outer surface of the underrun protector body in the longitudinal direction of the vehicle. Meanwhile, as shown in Patent Document 1, the underrun protector body is generally attached to the vehicle frame via a stay that extends downward. Therefore, when pressure is applied to the underrun protector body, it is expected that the stay will deform and tilt relative to the vehicle frame, and the pressure element will press obliquely against the outer surface of the underrun protector body in the longitudinal direction of the vehicle. However, no studies have been conducted to date that take into account such stay deformation.

[0008] In view of these points, an object of the present invention is to provide an underrun protector structure that can increase the static peak load that occurs during an offset collision without increasing the number of parts or weight, while taking into account deformation of the stay during an offset collision. [Means for solving the problem]

[0009] The present invention provides an underrun protector structure in which an underrun protector body is attached to a vehicle body frame via stays that extend downward, the underrun protector body extending in the vehicle width direction and having a rectangular tubular shape, and at least a portion of the upper surface of the underrun protector body that is located outside the stays in the vehicle width direction is an inclined surface that slopes downward from the outside to the inside in the vehicle fore-and-aft direction, The underrun protector main body includes an outer member located on the outer side in the longitudinal direction of the vehicle body, and an inner member located on the inner side in the longitudinal direction of the vehicle body, the outer member having an outer vertical plate portion extending in the up-down direction and also in the vehicle width direction, an outer upper horizontal plate portion extending from an upper end of the outer vertical plate portion toward the inner side in the longitudinal direction of the vehicle body, and an outer lower horizontal plate portion extending from a lower end of the outer vertical plate portion toward the inner side in the longitudinal direction of the vehicle body, the inner member having an inner vertical plate portion extending in the up-down direction and also in the vehicle width direction, an inner upper horizontal plate portion extending from an upper end of the inner vertical plate portion toward the outer side in the longitudinal direction of the vehicle body, and an inner lower horizontal plate portion extending from a lower end of the inner vertical plate portion toward the inner side in the longitudinal direction of the vehicle body, With the inner surfaces of the outer vertical plate portion and the inner surface of the inner vertical plate portion facing each other, the inner surface of the outer upper horizontal plate portion is joined to the outer surface of the inner upper horizontal plate portion, and the inner surface of the outer lower horizontal plate portion is joined to the outer surface of the inner lower horizontal plate portion, and the underrun protector main body has a first region in the vehicle width direction inward from the inclined surface and where the outer upper horizontal plate portion is horizontally disposed, a second region in which the inclined surface is disposed on the outer upper horizontal plate portion, and a third region whose shape gradually changes so as to connect the second region and the first region in the vehicle width direction, and the vertical length of the outer vertical plate portion is formed larger in the second region than in the first region, and the vertical length of the inner vertical plate portion is formed smaller in the second region than in the first region, When a load acts on the underrun protector main body from the outside to the inside in the longitudinal direction of the vehicle body, the load causes the stay to deform so as to rotate toward the inside in the longitudinal direction of the vehicle body, and the inclined surface becomes oriented horizontally as the stay rotates, and receives the load as an axial crushing load while oriented horizontally.

[0010] The inclined surfaces are preferably provided on both ends in the vehicle width direction on the upper surface of the underrun protector body.

[0012] It is preferable that at least a portion of the undersurface of the underrun protector body in the vehicle width direction is a second inclined surface that slopes upward from the outer side toward the inner side in the vehicle front-rear direction. [Effects of the Invention]

[0013] In the underrun protector structure of the present invention, at least a portion of the upper surface of the underrun protector body, which is on the outer side in the vehicle width direction than the stay, is formed as an inclined surface that slopes downward from the outer side to the inner side in the vehicle longitudinal direction, and therefore, for reasons described below, it is possible to increase the static peak load that occurs in an offset collision. Furthermore, because there is no need to place a crush prevention body on the inner side of the end of the underrun protector body in order to increase the static peak load in an offset collision, there is no increase in the number of parts or weight. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing an embodiment of an underrun protector structure according to the present invention; [Figure 2]2A is a partially enlarged view of the underrun protector structure shown in FIG. 1, FIG. 2B is a cross-sectional view at position X1, and FIG. 2C is a cross-sectional view at position X2. [Figure 3] 10A and 10B are diagrams illustrating the behavior of the underrun protector structure when a load is applied by a pressure tool. [Figure 4] 10 is a diagram showing the relationship between the stroke amount of a pressure tool and the magnitude of a load when the pressure tool presses an underrun protector main body. FIG. [Figure 5] 1. FIG. 4 is a diagram showing a modified example of the underrun protector main body shown in FIG. [Figure 6] FIG. 1 is a diagram showing a conventional underrun protector structure. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of an underrun protector structure according to the present invention will be described below with reference to the accompanying drawings. In this specification, the terms "upper," "lower," "front," "rear," "left," and "right" refer to directions relative to a person seated in the driver's seat in a vehicle to which the underrun protector structure is applied. The drawings prioritize parts necessary for explaining this embodiment, omitting parts that are not particularly necessary to explain, and exaggerating some of the illustrations. The means for attaching the various parts described below are not particularly limited, and may be, for example, welding, bolts and nuts, or rivets.

[0016] 1 shows an embodiment of an underrun protector structure according to the present invention. The underrun protector structure 1 of this embodiment includes a body frame 2, which is part of the structural members that form the skeleton of a vehicle, a stay 3 attached to the body frame 2, and an underrun protector 4 attached to the stay 3.

[0017] The vehicle frame 2 includes a pair of side frames 5 extending in the longitudinal direction of the vehicle body and spaced apart in the vehicle width direction, and a pair of reinforcing plates 6 attached to each side frame 5. In this embodiment, the side frame 5 includes a web 5a extending in the longitudinal direction of the vehicle body and substantially parallel to the up-down direction, an upper flange 5b extending inward in the vehicle width direction from the upper end of the web 5a, and a lower flange 5c extending inward in the vehicle width direction from the lower end of the web 5a, and is formed so that the web 5a, upper flange 5b, and lower flange 5c have a U-shaped cross section. As shown in the figure, the reinforcing plate 6 has an L-shaped cross section and is attached to the side frame 5 on the inner side in the vehicle width direction.

[0018] The stay 3 has an L-shaped cross section and extends downward from the side frame 5. The stay 3 includes a main stay 7 attached to the outer side of the side frame 5 in the vehicle width direction, a sub-stay 8 attached to the main stay 7 so as to face it, and a plate-shaped bracket 9 attached to the outer side of the main stay 7 in the fore-and-aft direction of the vehicle body.

[0019] The underrun protector 4 includes an underrun protector main body 10 that is rectangular and cylindrical and extends in the vehicle width direction and is attached to a bracket 9, and a reinforcement 11 (see Figure 1(b)) that is attached inside the underrun protector main body 10.

[0020] As shown in FIG. 2, the underrun protector body 10 of this embodiment, when attached to the bracket 9, is composed of an outer member 12 located on the outer side in the longitudinal direction of the vehicle body and an inner member 13 located on the inner side in the longitudinal direction of the vehicle body. As shown in FIG. 2(b), the outer member 12 has an outer vertical plate portion 12a that is generally parallel to the vertical direction and extends in the vehicle width direction, an outer upper horizontal plate portion 12b that extends inward in the longitudinal direction of the vehicle body from the upper end of the outer vertical plate portion 12a, and an outer lower horizontal plate portion 12c that extends inward in the longitudinal direction of the vehicle body from the lower end of the outer vertical plate portion 12a. The inner member 13 has an inner vertical plate portion 13a that is generally parallel to the vertical direction and extends in the vehicle width direction, an inner upper horizontal plate portion 13b that extends outward in the longitudinal direction of the vehicle body from the upper end of the inner vertical plate portion 13a, and an inner lower horizontal plate portion 13c that extends inward in the longitudinal direction of the vehicle body from the lower end of the inner vertical plate portion 13a. Note that the inner member 13 of this embodiment is slightly smaller than the outer member 12, as shown in FIG. 2(b). Specifically, the length from the inner surface of outer upper horizontal plate 12b to the inner surface of outer lower horizontal plate 12c is approximately equal to the length from the outer surface of inner upper horizontal plate 13b to the outer surface of inner lower horizontal plate 13c. Then, by fitting the inner member 13 inside the outer member 12 while the outer member 12 and the inner member 13 are facing each other, the rectangular cylindrical underrun protector body 10 is formed.

[0021] In this embodiment, the outer member 12 and the inner member 13 have different cross-sectional shapes in the vehicle width direction, and as a result, the cross-sectional shape of the underrun protector main body 10 also differs in the vehicle width direction. This point will be described in detail with reference to FIG. 2.

[0022] First, with regard to the outer member 12, the outer lower horizontal plate portion 12c has a uniform cross-sectional shape throughout the entire area in the vehicle width direction. In contrast, the outer vertical plate portion 12a has a vertical length of a in region A on the inner side in the vehicle width direction (the region from one bracket 9 to the other bracket 9 when the underrun protector main body 10 is attached to the two brackets 9) as shown in Fig. 2(b). However, in region B located at both ends of the underrun protector main body 10, the vertical length is d (d > a) as shown in Fig. 2(c). Furthermore, the vertical length of the outer vertical plate portion 12a gradually changes from length a shown in Fig. 2(b) to length d shown in Fig. 2(c) in region C from region A to region B. In region A, outer upper horizontal plate portion 12b extends at approximately the same height from the outer side to the inner side in the vehicle longitudinal direction as shown in Fig. 2(b), while in region B, as shown in Fig. 2(c), it forms an inclined surface that slopes at an angle φ so as to become lower from the outer side to the inner side in the vehicle longitudinal direction, and in region C, it gradually changes from the shape shown in Fig. 2(b) to the shape shown in Fig. 2(c). In this embodiment, the length of region B in the vehicle width direction is approximately 200 mm, and the length of region C in the vehicle width direction is approximately 100 mm. In this embodiment, region A extends approximately 100 mm outward in the vehicle width direction from the outer end of bracket 9 in the vehicle width direction.

[0023] The inner upper horizontal plate portion 13b and the inner lower horizontal plate portion 13c of the inner member 13 have the same cross-sectional shape throughout the entire area in the vehicle width direction. In contrast, the inner vertical plate portion 13a has a vertical length of c in region A as shown in FIG. 2(b), while in region B it has a vertical length of e (e < In region C, the length gradually changes from length c shown in FIG. 2(b) to length e shown in FIG. 2(c).

[0024] As described above, the underrun protector main body 10 of this embodiment has a rectangular cross section in region A, the angle of its upper surface gradually changes in region C, and in region B, the upper surface is inclined at angle φ so that it becomes lower from the outer side to the inner side in the fore-and-aft direction of the vehicle body. Note that angle φ is set in accordance with the expected rotation angle of the stay 3 relative to the body frame 2 when a load is applied to the underrun protector main body 10 on the outer side in the vehicle width direction than the stay 3, as will be described later.

[0025] As shown in Fig. 1(b), the reinforcement 11 extends in the vehicle width direction and is formed so that its cross section is U-shaped. The reinforcement 11 of this embodiment is formed to a length that includes the region A shown in Fig. 2 and the regions C located on both sides of the region A. By attaching the reinforcement 11 to the underrun protector main body 10, the region of the underrun protector main body 10 from the region A to the region C can be reinforced.

[0026] Next, the performance of the underrun protector structure 1 of this embodiment during an offset collision will be described in comparison with a conventional underrun protector structure 101 shown in FIG. 6. The conventional underrun protector structure 101 includes an outer member 112 and an inner member 113 that constitute an underrun protector main body 110. As shown in FIG. 6(c), the outer member 112 and the inner member 113 have a U-shaped cross section over their entire length in the vehicle width direction. In other words, the underrun protector main body 110 has a rectangular cross section over its entire length. Although not shown, the above-mentioned reinforcement 11 is disposed inside the underrun protector main body 110 at the above-mentioned position. The conventional underrun protector structure 101 is composed of the same components as the underrun protector structure 1, except for the underrun protector main body 110.

[0027] To confirm performance during an offset collision, for the conventional underrun protector structure 101, a model shown in FIG. 6 was created and a simulation was performed in which a load was applied from the outside in the longitudinal direction of the vehicle using a pressure element P (having a length in the vehicle width direction of approximately 200 mm) centered on a portion of the underrun protector main body 110 located approximately 200 mm inward from the outer end in the vehicle width direction. For the underrun protector structure 1, the model shown in FIG. 1 was created and a simulation was performed under the same conditions as for the underrun protector structure 101 described above. The results are shown in FIGS. 3 and 4. FIGS. 3(a) to 3(d) are diagrams that schematically show the behavior of the underrun protector structure 101 when a load is applied using the pressure element P, and FIGS. 3(e) to 3(h) are diagrams that schematically show the behavior of the underrun protector structure 1 when a load is applied using the pressure element P. The dashed line in Fig. 4 is a diagram showing the relationship between the stroke amount of the pressure element P and the magnitude of the load when the pressure element P presses the underrun protector main body 110, and the solid line in Fig. 4 is a diagram showing the relationship between the stroke amount of the pressure element P and the magnitude of the load when the pressure element P presses the underrun protector main body 10. Note that (a) to (h) shown in Fig. 4 correspond to (a) to (h) in Fig. 3, and for example, (b) in Fig. 4 shows the stroke amount of the pressure element P in Fig. 3(b).

[0028] As shown in FIG. 3(a), when the pressure element P presses vertically on the outer surface of the underrun protector main body 110 in the vehicle longitudinal direction, a moment is applied by the pressure element P to the stay 103, causing the stay 103 to deform so that it is tilted at an angle θ from the initial angle α (initial tilt from the horizontal at a certain point P1) shown in FIG. 3(a) (see FIG. 3(b)). The underrun protector main body 110 is also deformed by a load F from the pressure element P, as shown in FIG. 3(c), for example. At this time, a load f1, shown as a component of the load F, acts on the top surface of the underrun protector main body 110, and a load f2, shown as a component of the load F, acts on the outer surface of the underrun protector main body 110 in the vehicle longitudinal direction. As the load F increases further, the underrun protector main body 110 deforms as shown in FIG. 3(d), for example.

[0029] In contrast, when the pressure element P presses the outer surface of the underrun protector main body 10 in the vehicle longitudinal direction vertically, the stay 3 deforms so as to rotate by an angle θ from the initial angle α (initial inclination from the horizontal at a certain point P1) shown in FIG. 3(e) (see FIG. 3(f)). In the present embodiment shown in FIG. 2, the angle φ of the upper surface of the underrun protector main body 10 is set to match the angle θ. Therefore, when the stay 3 is inclined by the angle θ as shown in FIG. 3(f), the upper surface of the underrun protector main body 10 faces the horizontal direction. The underrun protector main body 10 is deformed by the load F of the pressure element P, as shown in FIG. 3(g), for example. At this time, a load f1' shown as a component of the load F acts on the upper surface of the underrun protector main body 10, and a load f2' as a component of the load F acts on the outer surface of the underrun protector main body 10 in the vehicle longitudinal direction. As shown in the figure, the magnitudes of loads f1' and f2' become smaller than the loads f1 and f2 shown in Figure 3(d). As the load F increases further, the underrun protector main body 10 deforms as shown in Figure 3(h), for example. Note that while the underrun protector main body 110 shown in Figure 3(d) is significantly deformed, the deformation of the underrun protector main body 10 under the same conditions is smaller, as shown in Figure 3(h).

[0030] Here, the relationship between the stroke amount of the pressure element P and the magnitude of the load in the underrun protector structure 101 and the underrun protector structure 1 will be described with reference to FIG. 4. As shown in FIG. 4, from the start of pressure application by the pressure element P until the state shown in FIGS. 3(b) and 3(f) is reached, the stroke amount of the pressure element P and the magnitude of the load are substantially the same for the underrun protector main body 110 and the underrun protector main body 10. However, once the load F of the pressure element P exceeds the state shown in FIGS. 3(b) and 3(f), the load capacity of the underrun protector main body 110 decreases significantly. In other words, the static peak load of the underrun protector main body 10 in an offset collision is greater than that of the underrun protector main body 110. The reason for this is thought to be that, as shown in FIG. 3(f), the pressure applied by the pressure element P tilts the stay 3 by an angle θ, causing the upper surface of the underrun protector main body 10 to be oriented horizontally. This means that the direction of the load F applied by the pressure element P is substantially the same as the direction of this upper surface, and therefore the load F is received as an axial crushing load on this upper surface. 3(c) and 3(g), when the same load F is applied from the pressure element P, the component force acting on the top surface of the underrun protector body 110 is load f1, while the component force acting on the top surface of the underrun protector body 10 is load f1', which is smaller than load f1. In other words, the force that deforms the underrun protector body 10 is smaller than the force that deforms the underrun protector body 110, and this is also thought to contribute to the increase in the static peak load of the underrun protector body 10 relative to the underrun protector body 110.

[0031] Next, a modified example of the above-mentioned underrun protector structure 1 will be described with reference to Fig. 5. The underrun protector structure 1 shown in Fig. 5(b) has an underrun protector main body 20 composed of an outer member 22 and an inner member 23, instead of the above-mentioned underrun protector main body 10. Furthermore, as shown in Fig. 5(a), the outer member 22 is composed of an outer vertical plate portion 22a, an outer upper horizontal plate portion 22b, and an outer lower horizontal plate portion 22c, and the inner member 23 is composed of an inner vertical plate portion 23a, an inner upper horizontal plate portion 23b, and an inner lower horizontal plate portion 23c.

[0032] With regard to the outer member 22, the outer vertical plate portion 22a has the same shape as that shown in Fig. 2(b) in the above-mentioned region A, whereas in the above-mentioned region B, the length in the up-down direction is d' (d' > a) as shown in Fig. 5(a), and gradually changes from length a to length d' in region C. The outer upper horizontal plate portion 22b extends at approximately the same height from the outer side to the inner side in the longitudinal direction of the vehicle body in region A, similar to the outer upper horizontal plate portion 12b in Fig. 2(b), and in region B, as shown in Fig. 5(a), it forms an inclined surface that is inclined at an angle φ so as to become lower from the outer side to the inner side in the longitudinal direction of the vehicle body, and gradually changes from the shape shown in Fig. 2(b) to the shape shown in Fig. 5(a) in region C. In region A, the outer lower horizontal plate portion 22c extends at approximately the same height from the outside to the inside in the fore-and-aft direction of the vehicle body, similar to the outer lower horizontal plate portion 12c in Figure 2(b), and in region B, it forms an inclined surface (second inclined surface) that is inclined at an angle γ so that it becomes higher from the outside to the inside in the fore-and-aft direction of the vehicle body, as shown in Figure 5(a).In region C, it gradually changes from the shape shown in Figure 2(b) to the shape shown in Figure 5(a).

[0033] The inner upper horizontal plate portion 23b and the inner lower horizontal plate portion 23c of the inner member 23 have the same cross-sectional shape throughout the entire area in the vehicle width direction. In contrast, the inner vertical plate portion 23a has a vertical length of c in region A as shown in FIG. 2(b), while in region B it has a vertical length of e' (e' < c), and in region C, the length gradually changes from that shown in FIG. 2(b) to that shown in FIG. 5(a).

[0034] In this way, the underrun protector main body 20 of this embodiment has a rectangular cross-sectional shape in region A, and the angle between its upper and lower surfaces gradually changes in region C, so that in region B its upper surface is inclined at an angle φ so that it becomes lower from the outside to the inside in the fore-and-aft direction of the vehicle body, and its lower surface is inclined at an angle γ so that it becomes higher from the outside to the inside in the fore-and-aft direction of the vehicle body.

[0035] The underrun protector structure 1 including the underrun protector body 20 is particularly effective in preventing under-run collisions of sports vehicles with low hood heights during an offset collision, as shown in FIG. 5(b). Specifically, when a vehicle with a low hood height offsets against the end of the underrun protector body 20, the stay 3 rotates in the direction of the arrow shown in FIG. 5(b). Therefore, when the stay 3 deforms in this manner, the undersurface of the underrun protector body 20 approaches a horizontal direction. This reduces deformation of the underrun protector body 20 during an offset collision, based on the same principle as when the upper surface of the underrun protector body 10 is oriented horizontally. Therefore, the underrun protector body 20 of this embodiment can increase the static peak load generated during an offset collision with a sports vehicle with a low hood height compared to conventional underrun protector bodies with a rectangular cross section. The angle γ is preferably set to the expected rotation angle of the stay 3 relative to the vehicle frame 2 when the stay 3 deforms in the direction of the arrow shown in FIG. 5(b) during an offset collision.

[0036] Although one embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and unless otherwise limited in the above description, various modifications and changes are possible within the scope of the spirit of the present invention as set forth in the claims. Furthermore, the effects of the above embodiment are merely examples of the effects that can be obtained from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

[0037] For example, in the above-described embodiment, the inclined surface of underrun protector main body 10 that slopes downward from the outside toward the inside in the fore-and-aft direction of the vehicle body may be at least a portion of the upper surface of underrun protector main body 10 that is located laterally outward of stay 3. That is, in the above-described embodiment, part of region A and region C were located laterally outward of the outer end of bracket 9 in the vehicle width direction, but only region B may be located laterally outward of the outer end of bracket 9 in the vehicle width direction. Furthermore, there may be a region on the upper surface of underrun protector main body 10 that is not an inclined surface as described above (for example, a region having a rectangular cross section with an upper surface oriented horizontally) located laterally outward of region B.

[0038] Furthermore, it is most preferable that the angle φ of the inclined surface be set to the above-mentioned angle θ (the expected rotation angle of the stay 3 relative to the body frame 2 when a load is applied to the underrun protector main body 10 on the outer side in the vehicle width direction of the stay 3), but it may be different. The angle θ may be calculated by simulation or may be found from the results of tests using an actual device. [Explanation of symbols]

[0039] 1: Underrun protector structure 2: Body frame 3: Stay 4: Underrun protector 10, 20: Underrun protector body 12b, 22b: Outside upper horizontal plate part (slanted surface) 22c: Outer lower horizontal plate part (second slope)

Claims

1. An underrun protector structure in which an underrun protector main body is attached to a vehicle body frame via a stay that extends downward, the underrun protector main body extends in the vehicle width direction and has a rectangular tubular shape, and at least a portion of the upper surface of the underrun protector main body that is on the outer side of the stay in the vehicle width direction is an inclined surface that slopes downward from the outer side to the inner side in the vehicle front-rear direction, The underrun protector main body includes an outer member located on the outer side in the longitudinal direction of the vehicle body, and an inner member located on the inner side in the longitudinal direction of the vehicle body, the outer member has an outer vertical plate portion that extends in the up-down direction and in the vehicle width direction, an outer upper horizontal plate portion that extends from an upper end of the outer vertical plate portion toward the inside in the fore-and-aft direction of the vehicle body, and an outer lower horizontal plate portion that extends from a lower end of the outer vertical plate portion toward the inside in the fore-and-aft direction of the vehicle body, the inner member has an inner vertical plate portion that extends in the up-down direction and in the vehicle width direction, an inner upper horizontal plate portion that extends from an upper end of the inner vertical plate portion toward the outside in the fore-and-aft direction of the vehicle body, and an inner lower horizontal plate portion that extends from a lower end of the inner vertical plate portion toward the inside in the fore-and-aft direction of the vehicle body, In the underrun protector main body, the inner surfaces of the outer vertical plate portion and the inner surfaces of the inner vertical plate portion face each other, and the inner surface of the outer upper horizontal plate portion is joined to the outer surface of the inner upper horizontal plate portion, and the inner surface of the outer lower horizontal plate portion is joined to the outer surface of the inner lower horizontal plate portion, The underrun protector body has a first region in the vehicle width direction, in which the outer upper horizontal plate portion is horizontally disposed inside the inclined surface, a second region in which the inclined surface is disposed on the outer upper horizontal plate portion, and a third region in the vehicle width direction, the shape of which gradually changes so as to connect the second region and the first region in the vehicle width direction. The vertical length of the outer vertical plate portion is formed to be larger in the second region than in the first region, The vertical length of the inner vertical plate portion is formed to be smaller in the second region than in the first region, When a load acts on the underrun protector body from the outside to the inside in the longitudinal direction of the vehicle body, the load causes the stay to deform so as to rotate inward in the longitudinal direction of the vehicle body, The inclined surface is oriented horizontally as the stay rotates, and receives the load as an axial crushing load while oriented horizontally.

2. The underrun protector structure according to claim 1 , wherein the inclined surfaces are provided on both ends of the upper surface of the underrun protector body in the vehicle width direction.

3. 3. The underrun protector structure according to claim 1, wherein at least a portion of the undersurface of the underrun protector body in the vehicle width direction is a second inclined surface that slopes higher from the outer side toward the inner side in the vehicle front-rear direction.

Images