JP2005225327A - Rear under run protector, and it's manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear under run protector capable of improving load resistant performance without increasing the thickness or disposing a reinforcing member. <P>SOLUTION: The rear under run protector is arranged in the rear part of a vehicle so as to extend in the vehicle width direction, and has a body 2 formed of a cylindrical body having a substantially rectangular cross section. The back section 2b located on the front side in the vehicle travelling direction in the body 2 is curved or folded so that a vertically substantially center section 10 projects than both vertical ends 11 and 12 forward in the vehicle travelling direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rear underrun protector and a manufacturing method thereof for preventing one vehicle from entering under another vehicle in a collision between vehicles.

  In heavy-weight vehicles such as trucks, it is known to provide a front underrun protector at the lower front of the vehicle in order to prevent medium-weight vehicles that collide due to a frontal collision, etc. from entering the heavy-weight vehicle. (For example, refer to Patent Document 1).

  By the way, in recent years, in order to prevent a vehicle that has collided with a heavyweight vehicle from the rear from entering under the heavyweight vehicle, it is desired to install a rear underrun protector at the lower rear portion of the vehicle. ing.

  Therefore, the present applicant has devised a rear underrun protector as shown in FIG.

  The rear underrun protector 1 has a RUP main body 2 arranged to extend in the vehicle width direction at the rear portion of the vehicle. The RUP main body 2 is formed from a cylindrical body having a substantially rectangular cross section, and extends substantially linearly in the vehicle width direction. The RUP main body 2 is attached to the rear portion of the vehicle body frame 6 via the attachment bracket 4 and the support 5, and supports the collision load to prevent the vehicle from getting into the vehicle.

Special table 2001-515432 gazette

  By the way, since the rear underrun protector supports the load at the time of collision, a predetermined rigidity is required. Therefore, as shown in FIG. 11, as a form of simulation at the time of a vehicle collision, a predetermined load (for example, 12.5% of the vehicle weight, etc.) F is applied inside a predetermined length (for example, 325 mm or less) from the outermost side of the vehicle. A test is conducted.

  At this time, if the strength of the RUP main body 2 is not sufficient, the RUP main body 2 is bent by the load F, and compressive stress is concentrated on the back side (the front side in the vehicle traveling direction). is there.

  Alternatively, stress concentrates on the joint of the RUP main body 2 with the mounting bracket 4 and the part may be broken.

  In order to increase the strength of the RUP main body 2, it is conceivable to increase the plate thickness of the RUP main body 2 or to provide a reinforcing member, but in that case, the cost and weight increase.

  On the other hand, if the RUP body 2 is formed using a high-tensile material (high-tensile steel), the strength can be improved without increasing the plate thickness or adding a reinforcing member. However, since the elongation rate of the high-tensile material is very small, the high-tensile material cannot be stretched at the time of a collision involving a large deformation greater than the deformation under the legal load, and a crack or the like occurs.

  The object of the present invention created in view of the above circumstances is to provide a rear underrun protector capable of improving load bearing performance without increasing the plate thickness or providing a reinforcing member. There is.

  In order to achieve the above object, the present invention is a rear underrun protector including a main body that is arranged to extend in the vehicle width direction at the rear portion of a vehicle and has a substantially rectangular cross section. The rear portion of the main body located on the front side in the vehicle traveling direction is formed such that the substantially central portion in the vertical direction protrudes forward in the vehicle traveling direction from both ends in the vertical direction.

  Further, the present invention is a rear underrun protector including a main body arranged so as to extend in the vehicle width direction at a rear portion of the vehicle, and the main body is formed from a cylindrical body having a substantially rectangular cross section. In the cylinder, the front portion located on the rear side in the vehicle traveling direction has a substantially central portion in the vertical direction protruding rearward or forward in the vehicle traveling direction from both ends in the vertical direction.

  Here, as for the said cylinder, the back part located in the vehicle advancing direction front side may protrude in the vehicle advancing direction front rather than the both ends of the up-down direction at the substantially vertical center part.

  Furthermore, the present invention relates to a method of manufacturing a rear underrun protector having a main body arranged to extend in the vehicle width direction at the rear part of a vehicle, and the vehicle travels in a cylindrical body having a substantially rectangular cross section. The surface located forward or backward in the direction is formed so that the substantially central portion in the vertical direction protrudes forward or backward in the vehicle traveling direction from both ends in the vertical direction, and the cylinder is used as the main body.

  According to the rear underrun protector of the present invention, it is possible to exhibit an excellent effect that the load bearing performance can be improved without increasing the plate thickness or providing the reinforcing member.

  An embodiment of the present invention will be described with reference to the accompanying drawings.

  The schematic configuration of the rear underrun protector according to the present embodiment is the same as that already described with reference to FIG.

  That is, the rear underrun protector 1 has a RUP main body 2 arranged so as to extend in the vehicle width direction at the rear portion of the vehicle.

  The RUP main body 2 is formed from a substantially rectangular cylindrical body, and extends substantially linearly in the vehicle width direction. The RUP main body 2 is attached to the rear portion of the vehicle body frame 6 via the mounting bracket 4 and the support 5, and supports the collision load to prevent the vehicle from getting into the vehicle.

  1 and 2 show a cross-sectional shape of the RUP main body 2 along the line II in FIG. 11. FIG. 1 shows a state before the collision, and FIG. 2 shows a state after the large deformation due to the collision. ing.

  As shown in FIG. 1, the RUP main body 2 includes an upper surface portion 2a, a back surface portion 2b positioned on the front side in the traveling direction of the vehicle, a lower surface portion 2c, and a front surface portion 2d positioned on the rear side in the traveling direction of the vehicle. Have.

  A feature of the RUP main body 2 of the present embodiment is that, as shown in FIG. 1, the back surface portion 2b and the front surface portion 2d each have a shape bulging outward. Specifically, the back surface portion 2b is curved with a predetermined curvature R1 so that the substantially central portion 10 in the vertical direction protrudes forward in the vehicle traveling direction from the both ends 11 and 12 in the vertical direction. That is, it gradually protrudes forward in the vehicle traveling direction as it goes from the upper and lower end portions 11 and 12 to the central portion 10, and the amount of protrusion at the central portion 10 is substantially maximized.

  On the other hand, the front portion 2d is curved with a predetermined curvature R2 so that the substantially central portion 15 in the vertical direction protrudes rearward in the vehicle traveling direction from the both ends 16 and 17 in the vertical direction. That is, it gradually protrudes toward the rear side in the vehicle traveling direction from the upper and lower end portions 16, 17 toward the central portion 15, and the amount of protrusion at the central portion 15 becomes substantially maximum. In the present embodiment, the curvature curvature R1 of the back surface portion 2b and the curvature curvature R2 of the front surface portion 2d are substantially equal.

  The rear underrun protector 1 of the present embodiment is formed by projecting the back surface portion 2b and the front surface portion 2d to the outside as described above, thereby improving the load bearing performance without increasing the weight of the RUP body 2. Is intended. Hereinafter, the reason why the load bearing performance is improved will be described.

  First, the effect obtained by projecting the rear surface portion 2b of the RUP main body 2 forward in the vehicle traveling direction will be described.

  As described in the section “Problems to be Solved by the Invention”, when a load F is applied to the rear underrun protector 1, a compressive stress is generated on the back surface portion 2 b of the RUP body 2.

  Here, as shown in FIG. 4, in the case of an RUP main body having a straight back surface 2b ′, in the back surface 2b ′, in the vicinity of upper and lower ends 11 ′ and 12 ′ continuous with the upper surface 2a ′ and the lower surface 2c ′. Is relatively high, and the rigidity on the central portion 10 'side is low. For this reason, when a compressive load is applied to the back surface portion 2b 'by the load F (see FIG. 11), the central portion 10' having low rigidity is deformed inward as shown in FIG. As a result, the compressive stress generated in the back surface portion 2b 'is concentrated in the vicinity of the upper and lower end portions 11' and 12 'as shown in FIG. Accordingly, a relatively large compressive stress is generated in the upper and lower end portions 11 ′ and 12 ′. When the upper and lower end portions 11 ′ and 12 ′ are buckled by the stress, the RUP body 2 ′ is broken.

  On the other hand, in the rear underrun protector 1 of the present embodiment, as shown in FIG. 3A, the central portion 10 of the back surface portion 2b of the RUP main body 2 is located outside the upper and lower end portions 11 and 12. Since it is formed so as to protrude, the rigidity on the central portion 10 side of the back surface portion 2b is higher than that shown in FIG. That is, the central portion 10 can also receive a load to some extent. For this reason, the compressive stress which generate | occur | produces in the back surface part 2b by the load F is disperse | distributed to an up-down direction as shown in FIG.3 (b), and does not concentrate on a local part. Therefore, the maximum compressive stress generated in the back surface portion 2b is lower than the compressive stress (maximum compressive stress) generated in the upper and lower end portions 11 'and 12' of the rear underrun protector shown in FIG. As a result, the load bearing performance of the RUP main body 2 as a whole is improved.

  Further, since the rear surface portion 2b protrudes to the outside, the section modulus of the RUP main body 2 increases, and this also acts effectively on the load bearing performance.

  In order to confirm the effect of improving the load resistance performance by projecting the central portion 10 of the back surface portion 2b to the outside, the present inventors changed the protruding amount P (see FIG. 3) of the central portion 10 in various ways to evaluate the test ( Analysis). The result is shown in FIG.

  FIG. 6 is a graph showing the relationship between the load applied to the test piece and the amount of displacement of the test piece, with the horizontal axis indicating the amount of displacement (mm) and the vertical axis indicating the load (kN). As the test piece, a cylindrical body having a vertical length (height) of 125 mm, a width of 75 mm, and a plate thickness of 3.2 mm was used.

  The protrusion amount P of the central portion 10 is 0 for the line a, 2 mm for the line b, 5 mm for the line c, and 10 mm for the line d. That is, the line a corresponds to the RUP main body having the back surface portion 2b as shown in FIG. Moreover, the front part 2d was made into linear form in all the test pieces.

  As can be seen from the figure, the buckling yield load, that is, the load at the point (peak of the mountain) where only the displacement amount increases without increasing the load, the higher the protrusion amount P of the central portion 10 is. From this, it can be seen that the load bearing performance of the RUP body 2 is improved if the central portion 10 of the back surface portion 2b is projected outward.

  Here, looking only at the result of FIG. 6, it seems that the load bearing performance is improved as the protruding amount P of the central portion 10 is increased. However, if the protruding amount P of the central portion 10 is extremely increased, It is conceivable that stress concentrates on the central portion 10 and the load bearing performance decreases. Therefore, it is preferable to appropriately set the protrusion amount P of the central portion 10 of the back surface portion 2b in consideration of the size, plate thickness, material, and the like of the RUP main body 2.

  Next, an effect obtained by projecting the front portion 2d rearward in the vehicle traveling direction will be described.

  The effect of projecting the front portion 2d to the outside is that, when the RUP body 2 is formed of a high strength high strength material (high tensile steel), it is possible to have a degree of freedom of deformation. is there. That is, by projecting the front portion 2d outward, the material of the RUP body 2 itself can be deformed (bent) without being stretched, so that the amount of collision energy absorbed is improved. Therefore, the RUP main body 2 can be formed from a high-tensile material, and the load bearing performance can be improved.

  For example, in order to prevent the strength of the RUP main body 2 from being lowered when subjected to an impact accompanied by a large deformation greater than the deformation under the legal load, the back surface portion 2b needs to be bent as a neutral neutral surface. . Accordingly, the front surface portion 2d needs to have a longer distance (extend) in the longitudinal direction by the bending radius (that is, the width of the upper surface portion 2a) with respect to the back surface portion 2b.

  In the RUP main body 2 ′ having a straight front portion 2 d ′ as shown in FIG. 4, the front portion 2 d ′ does not have a shape margin that allows the distance in the longitudinal direction to be increased. Therefore, when the RUP body 2 'is bent, the material of the front portion 2d' needs to be stretched. For this reason, a high-tensile material having a small elongation rate cannot cope with a large deformation, a crease or a crack occurs, and the strength is remarkably lowered after the occurrence.

  On the other hand, in the rear underrun protector 1 of the present embodiment, since the front part 2d protrudes outward, it is possible to allow the distance in the longitudinal direction of the front part 2d to be increased. Specifically, when the RUP main body 2 is deformed, the RUP body 2 is bent so that the vicinity of the back surface portion 2b becomes a neutral surface of the curve and the front surface portion 2d becomes the outer surface of the curve. Accordingly, the front portion 2d has a longer distance in the longitudinal direction during this bending deformation, but since the front portion 2d protrudes outward, there is a margin in the vertical length of the front portion 2d, which is the front portion 2d. Allows the distance to be extended in the longitudinal direction. That is, when the RUP body 2 as shown in FIG. 1 is bent, as shown in FIG. 2, the front portion 2d moves inward and becomes almost linear. The length in the vertical direction of the front portion 2d is shorter than that before bending. This shortened portion is used to increase the distance in the longitudinal direction of the front portion 2d. In other words, by allowing the central portion 15 of the front portion 2d to protrude outward, an allowance that allows elongation in the longitudinal direction during bending deformation is provided. Therefore, since the material itself does not need to be stretched during bending deformation, even a high-tensile material having a low elongation rate can be deformed without causing cracks or breakage. The front portion 2d does not necessarily need to be linear after being bent and deformed.

  As described above, in the rear underrun protector 1 of the present embodiment, the stress generated in the back surface portion 2b can be dispersed and reduced, and a high-tensile material can be used for the RUP main body 2, so that the plate thickness can be increased. Without providing a reinforcing member, it is possible to remarkably improve the load bearing performance and the collision energy absorption amount of the RUP main body 2, and thus the rear underrun protector 1 as a whole.

  In addition, if the curvature curvature R1, R2 of the back surface part 2b of the RUP main body 2 and the front surface part 2d are made equal and symmetrical as in the present embodiment, the deformation of the RUP main body 2 (cylinder) becomes easy. At the same time, management is easy because there is no problem that the back part 2b and the front part 2d are mistaken.

  The present invention is not limited to the above embodiment.

  For example, as shown in FIG. 7, the shape of the back surface portion 2 b and the front surface portion 2 d is a straight portion inclined so as to protrude outward from the upper end portions 11, 16 and the lower end portions 12, 17 toward the central portions 10, 15. 20 and a rounded portion 21 that connects the straight portions 20 may be used.

  Moreover, as shown in FIG. 8, it is good also as a shape bent so that the back part 2b and the front part 2d may protrude partially. That is, in this embodiment, the back surface portion 2b and the front surface portion 2d are formed on both side portions in the vertical direction, and are inclined linearly between the inclined portions 25 inclined so as to protrude outward toward the center portion. And a straight line portion 26 to be connected.

  As described above, the present invention is not limited in the shapes of the back surface portion 2b and the front surface portion 2d, and various shapes such as those having a plurality of round portions (composite round shape) and involute shapes are conceivable.

  Furthermore, since it is the purpose to secure the margin for bending deformation in the projecting direction of the front portion 2d, the center portion 15 in the vertical direction is more than the both ends 16 and 17 in the vertical direction as shown in FIG. Also, the shape may be curved or bent so as to protrude inward (front side in the vehicle traveling direction).

  Moreover, as shown in FIG. 10, in order to increase the rigidity of the RUP main body 2, the present invention can also be applied to a configuration in which the cylinders 30 are stacked one above the other. In other words, the back surface portion 2b and / or the front surface portion 2d of each cylindrical body 30 may be formed by being bent or bent so that the center portion in the vertical direction protrudes outside the upper and lower end portions. In addition, you may make the front part 2d of each cylinder 30 protrude inward similarly to the form of FIG.

It is sectional drawing along the II line of FIG. 11, and has shown the state before the deformation | transformation of the RUP main body of the rear underrun protector which concerns on one Embodiment of this invention. It is sectional drawing along the II line of FIG. 11, and has shown the state after the deformation | transformation of the RUP main body of the rear underrun protector which concerns on one Embodiment of this invention. It is a figure for demonstrating the stress which generate | occur | produces in the back surface part of the RUP main body of the rear underrun protector which concerns on one Embodiment of this invention. It is sectional drawing of the RUP main body which has a linear back part and front part. FIG. 5 is a diagram for explaining a stress generated in a back surface portion of the RUP main body of FIG. 4. It is a graph which shows the relationship between the load and displacement amount which concern on a RUP main body. It is sectional drawing of the RUP main body of the rear underrun protector which concerns on other embodiment of this invention. It is sectional drawing of the RUP main body of the rear underrun protector which concerns on other embodiment of this invention. It is sectional drawing of the RUP main body of the rear underrun protector which concerns on other embodiment of this invention. It is sectional drawing of the RUP main body of the rear underrun protector which concerns on other embodiment of this invention. It is a schematic perspective view of a rear underrun protector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rear underrun protector 2 RUP main body 2b Rear surface part 2d Front part 10,15 Center part 11,16 Upper end part 12,17 Lower end part

Claims (4)

A rear underrun protector including a main body made of a cylindrical body having a substantially rectangular cross section, arranged to extend in the vehicle width direction at the rear of the vehicle,
A rear underrun protector characterized in that a rear portion located on the front side in the vehicle traveling direction of the main body is formed such that a substantially central portion in the vertical direction protrudes forward in the vehicle traveling direction from both ends in the vertical direction. . A rear underrun protector having a body arranged to extend in the vehicle width direction at the rear of the vehicle,
The main body is formed of a cylindrical body having a substantially rectangular cross section, and the cylindrical body has a front portion located on the rear side in the vehicle traveling direction, and a substantially central portion in the vertical direction is rearward in the vehicle traveling direction than both ends in the vertical direction. Or a rear underrun protector that protrudes forward.   3. The rear underrun according to claim 2, wherein the cylindrical body has a rear portion positioned on the front side in the vehicle traveling direction, and a substantially central portion in the vertical direction protrudes forward in the vehicle traveling direction from both ends in the vertical direction. Protector. A method of manufacturing a rear underrun protector comprising a main body arranged to extend in the vehicle width direction at the rear of the vehicle,
A surface of the cylindrical body having a substantially rectangular cross section that is positioned forward or rearward in the vehicle traveling direction is formed such that a substantially central portion in the vertical direction protrudes forward or backward in the vehicle traveling direction from both ends in the vertical direction. A method of manufacturing a rear underrun protector, wherein a cylindrical body is the main body.

Images