JP4853914B2 - Auto body front structure - Google Patents

Description

  According to the present invention, when a vehicle collides while moving forward and a load (impact force) is applied to the vehicle body from the front, the vehicle body moves from the front side toward the rear side in order over time. The present invention relates to a vehicle body front structure that is deformed.

  Conventionally, the above-mentioned automobile body front structure is disclosed in Patent Document 1 below. According to this publication, the front portion of the vehicle body includes a pair of left and right side members extending in the longitudinal direction of the vehicle body, and an apron member disposed above the side members. This apron member supports the suspension device for the front wheels arranged on the outer side of each side member. A concave portion is formed on the outer surface of the midway portion so as to avoid contact between the midway portion in the longitudinal direction of each side member and the front wheel during steering. When a first load is applied to the side member from the front, a deformation promoting portion that accelerates the deformation so that the front portion of the side member is compressed and deformed (plastically deformed) by the first load is provided in front of the side member. It is formed in the part.

  When the automobile collides while moving forward and a load is applied to the side member from the front, the front portion of the side member is compressed and deformed from the front end side toward the rear end side by the deformation promoting portion. Then, by this deformation, the kinetic energy which is to be given to the vehicle body based on the load at the time of the collision is absorbed. Thereby, since the said load is relieve | moderated, the load given to a passenger | crew is restrained small and this passenger | crew is protected.

On the other hand, an engine unit serving as a driving source for driving is disposed between the left and right side members, and the engine unit is supported by the side members by brackets. Here, as described above, a concave portion is formed in the middle portion of each side member, and the strength of the middle portion tends to decrease due to the concave portion. Therefore, the midway part is sufficiently reinforced by fixing the bracket to the midway part of each side member. In other words, the above-described bracket compensates for a decrease in the strength of the middle part of the side member.
JP 2000-289651 A

  By the way, as described above, at the time of the collision of the automobile, the energy to be given to the vehicle body based on the load at the time of the collision is absorbed by the compressive deformation of the front part of the side member.

  However, as described above, the middle part of the side member is sufficiently reinforced by the bracket for the engine unit. For this reason, it is prevented that the middle part of the side member is deformed by the load. Therefore, when the load is large, the energy absorption amount (EA amount) due to the deformation of the side member tends to be insufficient, and the load may be insufficiently relaxed.

  The present invention has been made paying attention to the above situation, and an object of the present invention is to absorb a desired energy absorption amount for energy applied to the vehicle body based on a load applied to the vehicle body at the time of a car collision. Thus, the load can be sufficiently relaxed.

The invention of claim 1 includes a pair of left and right side members 8 extending in the longitudinal direction of the vehicle body 2 and an apron member 37 disposed above the side members 8. The midway portion supports the suspension device 3 for the front wheel 4 arranged on the outer side of the member 8 and avoids contact between the longitudinal midway portion 40 of each side member 8 and the front wheel 4 during steering. A recess 41 is formed on the outer surface of the front member 40. When the first load A is applied to the side member 8 from the front side, the front portion 43 of the side member 8 is compressed and deformed. In the vehicle body front part structure in which the deformation promoting part 44 is formed,
The apron member 37 and the middle part 40 of the side member 8 are provided between the apron member 37 and a connecting member 46 for connecting the members 37 and 40 to each other, and a second load B larger than the first load A is applied to the side member 8. When the midway portion 40 is given from the front, the midway portion 40 is bent and deformed toward the inner side C in the width direction of the vehicle body 2 .
The concave portion 41 is formed to have a circular arc shape that is convex inward in the width direction of the vehicle body 2 in a plan view of the vehicle body 2, and is formed over the entire vertical direction of the middle portion 40 of the side member 8, The lower end edge of the coupling member 46 is formed along the upper end edge of the recess 41 and is coupled to the upper end edge of the recess 41 .

  In addition to the invention of claim 1, the invention of claim 2, as viewed from the line of sight along the longitudinal direction of the vehicle body 2 (FIG. 4), It was formed to head towards.

  In addition to the invention of claim 1 or 2, the invention of claim 3 is arranged below the side members 8 and is attached to the front and rear attachment parts 24 and 26 at the rear part 23 of the side members 8. When the frame 20 is provided and a load is applied to the rear portion 23 of the side member 8 from the front thereof, the load allows the subframe 20 to be detached from the rear mounting portion 26 of the side member 8. When a third load D greater than 2 loads B is applied to the rear portion 23 of the side member 8 from the front thereof, the portion 55 between the concave portion 41 and the front mounting portion 24 of the side member 8 is moved upward E. A fragile portion 56 is formed in the side member 8 so as to bend and deform.

  In this section, the reference numerals appended to the above terms are not to be construed as limiting the technical scope of the present invention to the section “Example” described later or the contents of the drawings.

  The effects of the present invention are as follows.

The invention of claim 1 includes a pair of left and right side members extending in the longitudinal direction of the vehicle body, and an apron member disposed above each of the side members, and the apron member is disposed outward of the side members. Supporting the suspension device for the front wheel to be disposed, forming a recess in the outer surface of the midway portion so as to avoid contact between the longitudinal middle portion of each side member and the front wheel during steering, and In the vehicle body front part structure in which a deformation promoting portion is formed in the front part of the side member so that the front part of the side member is compressed and deformed when a first load is applied to the member from the front,
When a connecting member is provided between the apron member and the middle part of the side member to couple them together, and a second load greater than the first load is applied to the middle part of the side member from the front The intermediate portion is bent and deformed inward in the width direction of the vehicle body. According to this, the following effects are produced.

  That is, when the automobile according to the present invention collides while moving forward and a first load is applied to the side member of the vehicle body from the front, first, the front portion of the side member is moved rearward from the front end side by the deformation promoting portion. It is compressed and deformed toward the end side, and a predetermined deformation is obtained at this front part.

  Here, as described above, the apron member supports the suspension device and has high strength and rigidity. The apron member and the middle part of the side member are coupled to each other by a coupling member. As a result, the middle part of the side member is reinforced by the apron member via the coupling member, and the strength and rigidity are increased more than the front part of the side member.

  For this reason, when the first load is applied to the front part of the side member as described above, the first load also acts on the middle part of the side member, but the middle part of the side member reinforced as described above. The part is opposed to the first load with a large resistance force, and it is temporarily prevented that the intermediate part is deformed.

  It is assumed that the collision has progressed and the compressive deformation of the front portion of the side member by the first load is almost completed. Here, as described above, the resistance of the middle part of the side member to the first load is larger than that of the front part. For this reason, when the collision further progresses, the load applied to the middle part of the side member from the front becomes a second load larger than the first load. Then, due to the second load, the middle part of the side member in which the recess is formed is bent and deformed inward in the width direction of the vehicle body as described above, and a predetermined deformation is obtained in the middle part. .

  As a result, when the vehicle collides while moving forward and a load is applied to the vehicle body from the front, the load causes the front part of the side member of the vehicle body and the middle part on the rear side of the front part to change over time. In this order, predetermined deformations are made. For this reason, a desired energy absorption amount can be obtained by each of the above deformations, and the load can be sufficiently relaxed.

  According to a second aspect of the present invention, the inner surface of the concave portion is formed so as to go inward in the width direction of the vehicle body as it goes downward as viewed from the line of sight along the longitudinal direction of the vehicle body.

  For this reason, the upper part in the middle part of the side member can be kept large in width, and its strength and rigidity are larger than that of the lower part. Therefore, the upper part of the midway part, together with the coupling member and the apron member, more strongly opposes the first load and the second load, and the midway part tends to bend in an unintended direction such as upward, More reliably prevented. As a result, a predetermined deformation can be obtained more reliably in the midway portion.

  On the other hand, the width dimension of the lower part of the middle part can be reduced, and the strength and rigidity can be set lower. For this reason, the bending deformation of the midway part due to the second load is rapidly induced by the lower part of the midway part smoothly starting the deformation. Therefore, the predetermined deformation of the midway can be obtained with good timing.

  According to a third aspect of the present invention, a subframe is provided below each side member, and is attached to the front and rear mounting portions at the rear portion of the side members, and a load is applied to the rear portion of the side member from the front thereof. When the load allows the sub-frame to be detached from the rear mounting portion of the side member, a third load larger than the second load is applied to the rear portion of the side member from the front. A fragile portion is formed in the side member so that a portion of the side member between the concave portion and the front mounting portion is bent and deformed upward.

  Here, the rear part of the side member is reinforced by the sub-frame, whereby the rear part of the side member has higher strength and rigidity than the midway part.

  For this reason, when the second load is applied to the middle part of the side member as described above, the second load also acts on the rear part of the side member, but the rear part of the side member reinforced as described above is It is once prevented that the rear portion is deformed against the second load with a large resistance.

  It is assumed that the collision progresses and the bending deformation of the middle part of the side member due to the second load is almost completed. Here, as described above, the resistance of the rear portion of the side member against the second load is larger than that of the midway portion. For this reason, when the collision further progresses, the load applied to the rear portion of the side member from the front becomes a third load larger than the second load. Then, by the third load, the portion of the side member in which the weakened portion is formed is bent and deformed upward as described above, and a predetermined deformation is obtained at the rear portion of the side member.

  Further, as described above, when any load (any one of the first load, the second load, and the third load) is applied to the rear portion of the side member from the front thereof, the rear mounting portion of the side member On the other hand, the subframe is separated. Here, as described above, particularly when the side member portion is bent and deformed upward based on the third load, the front of the sub-frame attached to the front mounting portion is interlocked with the bending deformation. The part side is moved upward with respect to the rear mounting part. For this reason, the attachment part of the sub-frame and the rear attachment part is distorted by the upward movement of the front part side of the sub-frame. It is said. Therefore, the detachment of the subframe with respect to the rear attachment portion of the side member can be easily and smoothly performed.

  As described above, since the subframe 20 is separated from the rear mounting portion 26 of the side member 8, bending deformation of the side member above the portion is hindered by the subframe. Smoothly. Therefore, the side member portion is greatly bent and deformed, and at the same time, the side member is pushed backward by the third load, so that the bending deformation is smoothly promoted. That is, a predetermined deformation can be more reliably obtained at the rear part of the side member.

  As a result of the above, when the vehicle collides while moving forward and a load is applied to the vehicle body from the front, this load causes the front part of the side member of the vehicle body, the middle part of the rear part of the front part, and the middle part thereof. The rear part on the rear side of the part undergoes predetermined deformation in this order over time. For this reason, a desired energy absorption amount can be obtained by each of the above deformations, and the load can be sufficiently relaxed.

  The vehicle body front structure according to the present invention relates to the energy applied to the vehicle body based on the load applied to the vehicle body at the time of the collision of the vehicle so that the desired energy absorption amount can be absorbed to sufficiently relax the load. In order to realize the object, the best mode for carrying out the present invention is as follows.

  That is, the front part of the vehicle body includes a pair of left and right side members extending in the longitudinal direction of the vehicle body, and an apron member disposed above each side member. This apron member supports the suspension device for the front wheels arranged on the outer side of each side member. A concave portion is formed on the outer surface of the midway portion so as to avoid contact between the midway portion in the longitudinal direction of each side member and the front wheel during steering. When a first load is applied to the side member from the front, a deformation promoting portion is formed at the front portion of the side member to promote the deformation so that the front portion of the side member is compressed and deformed by the first load. ing.

A connecting member is provided between the apron member and the middle part of the side member to connect them together. When a second load larger than the first load is applied to the middle part of the side member from the front, the middle part is bent and deformed inward in the width direction of the vehicle body. The concave portion is formed to have a circular arc shape that is convex inward in the width direction of the vehicle body in a plan view of the vehicle body, and is formed over the entire vertical direction of the middle portion of the side member. The lower end edge of the coupling member is formed along the upper end edge of the recess, and is coupled to the upper end edge of the recess.

  In order to explain the present invention in more detail, an embodiment thereof will be described with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes an automobile, and an arrow Fr indicates the front in the traveling direction of the automobile 1.

  The automobile 1 is supported by a sheet metal body 2, a pair of left and right front wheels 4 that are respectively steerably suspended by a suspension device 3 at the front part of the body 2, and a bracket 5 at the front part of the body 2. And an engine unit 6 for driving the vehicle. The front part of the vehicle body 2 is supported on the traveling surface 7 by the suspension device 3 and the front wheel 4.

  The front portion of the vehicle body 2 includes a pair of left and right side members 8 extending in the longitudinal direction of the vehicle body 2 and a cross member 9 that couples the front end portions of the left and right side members 8 to each other. Further, the side member 8 constitutes a front side thereof, and a front horizontal member 11 extending substantially horizontally, and an inclined member 12 extending from the rear end portion of the front horizontal member 11 toward the rear lower inclination direction. And a rear horizontal member 13 that constitutes the rear side of the side member 8 and is positioned lower than the front horizontal member 11 and extends substantially horizontally from the rear end of the inclined member 12.

  The front horizontal member 11 of the side member 8 includes a U-shaped member main body 15 having a cross section that opens outward as viewed in the longitudinal direction of the vehicle body 2, and the upper and lower ends of the member main body 15. A pair of downwardly extending outward flanges 16 and 17 that extend integrally from the edge portion and the outwardly flanged flanges 16 and 17 are connected by spot welding S1 and S2 so as to close the opening of the member body 15. A coupling plate 18 that couples the outward flanges 16 and 17 to each other is provided. Thus, the front horizontal member 11 of the side member 8 has a closed cross-sectional structure. In addition, the inclined member 12 and the rear horizontal member 13 have the same configuration as the front horizontal member 11 and have a closed cross-sectional structure.

  The front portion of the vehicle body 2 includes subframes 20 disposed below the side members 8. The subframe 20 includes a subframe main body 21 provided so as to straddle the left and right side members 8 in a plan view of the vehicle body 2, and a pair of left and right mounting arms 22 protruding upward from the front end portion of the subframe main body 21. I have. The protruding end portions of the attachment arms 22 are attached to the front attachment portions 24 formed on the lower surfaces of the rear portions 23 of the side members 8 by fasteners 25. The front mounting portion 24 is formed below the member main body 15 at the rear end portion of the front horizontal member 11.

  On the other hand, the rear end portion of the subframe main body 21 is attached to a rear attachment portion 26 formed on the lower surface of the rear portion 23 of each side member 8 by a fastener 27. The rear mounting portion 26 is a sheet metal hollow shape fixed to the lower surface of the rear end portion of the inclined member 12 on the main body side by welding. The nut of the fastener 27 is welded to a part of the lower surface plate constituting the lower end portion of the rear mounting portion 26. The rear end portion of the subframe main body 21 is brought into contact with the lower surface of the rear mounting portion 26, and the bolt of the fastener 27 passing through the rear end portion from below is screwed into the nut. Thereby, as described above, the rear end portion of the subframe main body 21 is attached to the rear attachment portion 26 by the fastener 27. The sub-frame 20 serves as a cross member that couples the left and right side members 8 to each other.

  The front portion of the vehicle body 2 includes side walls 29 arranged on the outer sides of the side members 8, and a space 30 is formed between the left and right side walls 29. A door opening 31 is formed in the side wall 29. The lower opening edge of the door opening 31 is a side sill 32, and the front opening edge is a front pillar 33. Each of the side sill 32 and the front pillar 33 has a closed cross-sectional structure with high strength and rigidity, and is a skeleton member of the vehicle body 2. The front end portion of the side sill 32 and the lower end portion of the front pillar 33 are located at substantially the same position as the inclined member 12 of the side member 8 in the longitudinal direction of the vehicle body 2, and are firmly attached to the inclined member 12 by the connecting member 34. Are combined.

  An apron member 37 having high strength and rigidity is projected from a middle part in the longitudinal direction of each front pillar 33 toward the front. Each of the apron members 37 is disposed above the side members 8. A suspension tower 38 is installed on the side member 8 and the apron member 37 and is firmly supported. The front wheel 4 is disposed on the outer side of the side member 8. The front wheel 4 is supported by the suspension device 3 on the subframe 20, the suspension tower 38, and the apron member 37 via the suspension tower 38.

  A concave portion is formed on the outer surface of the midway portion 40 so as to avoid contact between the midway portion 40 in the longitudinal direction of the front horizontal member 11 of each side member 8 and the front wheel 4 during steering (dashed line in FIG. 1). 41 is formed. When viewed from the line of sight along the longitudinal direction of the vehicle body 2 (FIG. 4), the inner surface of the recess 41 is formed so as to go inward in the width direction of the vehicle body 2 as it goes downward. Thereby, the width dimension of the upper part of the middle part 40 of the side member 8 is made larger than the lower part. The bracket 5 of the engine unit 6 is supported on the front horizontal member 11 of each side member 8 corresponding to the rear portion of the recess 41 and on the subframe 20.

  When a first load A is applied to the side member 8 from the front, the first load A causes the front portion 43 of the front horizontal member 11 of the side member 8 to be compressed and deformed (plastic deformation). A deformation promoting portion 44 for promoting is formed on the front portion 43 of the side member 8. Specifically, the deformation promoting portion 44 is a plurality of beads extending in the vertical direction and the width direction of the vehicle body 2.

  A connecting member 46 is provided between the upper part of the middle part 40 of the side member 8 and the protruding part of the apron member 37 and connects the members 37 and 40 to each other. The coupling member 46 includes an outer panel 47 that integrally extends upward from an upper end edge of the coupling plate 18 that constitutes the middle portion 40 of the side member 8, and a spot on the inner surface side of the outer panel 47. An inner panel 48 that is coupled by welding S3 and extends further upward than the upper end edge of the outer panel 47 is provided.

  The lower edge portion of the inner panel 48 is sandwiched between the outward flange 16 on the upper side of the midway portion 40 and the upper edge portion of the coupling plate 18 and is coupled to each other by the spot welding S1. On the other hand, the upper edge of the inner panel 48 is joined to the protruding edge of the apron member 37 by spot welding S4. The inner panel 48 is thicker than the outer panel 47. Further, the intermediate portions 47a and 48a between the outer panel 47 and the inner panel 48 in the vertical direction have a closed cross-sectional structure. As a result, the strength and rigidity of the coupling member 46 are enhanced.

  A reinforcing plate 51 that reinforces the midway portion 40 of each side member 8 is provided. The reinforcing plate 51 is joined to the inner surface of the member main body 15 of the midway portion 40 in the midway portion 40 of the side member 8 and is joined by spot welding S5. Further, the lower end edge portion of the reinforcing plate 51 is sandwiched between the outward flange 17 on the lower side of the midway portion 40 and the lower end edge portion of the coupling plate 18 and is coupled to each other by the spot welding S2.

  The thickness of the reinforcing plate 51 is larger than that of each part of the front horizontal member 11 of the side member 8, and the longitudinal direction of the midway portion 40 is in the middle of the reinforcing plate 51 in the vertical direction. A bead 52 is formed extending in the direction. As a result, the midway portion 40 of the side member 8 is reinforced by the reinforcing plate 51.

  When a second load B greater than the first load A is applied to the middle part 40 of the side member 8 from the front thereof, the middle part 40 is caused by the presence of the recess 41 formed in the middle part 40. Regardless of the provision of the connecting member 46 and the reinforcing plate 51, the body member 2 is bent and deformed toward the inner side C in the width direction.

  When the first load A or the second load B is applied to the side member 8, the attachment of the subframe 20 to the front and rear attachment portions 24, 26 of the side member 8 is not released. It is made strong. On the other hand, when a third load D larger than the second load B is applied to the rear portion 23 of the side member 8 from the front thereof, the third load D causes the rear attachment portion 26 to the side member 8 to move toward the rear mounting portion 26. The rear end portion of the subframe 20 can be detached (a chain line in FIG. 3).

  The detachment of the subframe 20 from the rear mounting portion 26 of the side member 8 based on the third load D described above causes, for example, a shearing force, a bending force, or a tensile force to be applied to the bolt of the fastener 27 by the third load D. This is accomplished by breaking the bolt as provided. Further, the detachment is achieved, for example, when a part of the lower surface plate of the rear mounting portion 26 welded to the nut of the fastener 27 is torn off from the other portion of the rear mounting portion 26 by the third load D. Is done. The detachment of the subframe 20 from the rear mounting portion 26 of the side member 8 may be based on the first load A or the second load B.

  The reinforcing plate 51 is positioned in a portion 55 between the front mounting portion 24 and the recessed portion 41 of the side member 8 in the longitudinal direction of the side member 8. A notch is formed in the lower rear portion of the reinforcing plate 51, and the notch is a weakened portion 56 for locally lowering the strength of the lower portion side of the portion 55. When the third load D is applied from the front to the rear portion 23 of the side member 8, the portion 55 is bent toward the upper direction E due to the presence of the weakened portion 56 in the portion 55 of the side member 8. It can be deformed.

  In the above configuration, when the automobile 1 collides while moving forward and the first load A is applied to the side member 8 of the vehicle body 2 from the front, first, the front portion 43 of the side member 8 is formed by the deformation promoting portion 44. Is compressed and deformed from the front end side toward the rear end side, and a predetermined deformation is obtained in the front portion 43.

  Here, as described above, the apron member 37 supports the suspension device 3 and has high strength and rigidity. The apron member 37 and the middle part 40 of the side member 8 are coupled to each other by a coupling member 46, and a reinforcing plate 51 is coupled to the middle part 40. Accordingly, the midway portion 40 of the side member 8 is reinforced by the apron member 37 through the coupling member 46 and also by the reinforcing plate 51, and is stronger and rigid than the front portion 43 of the side member 8. And is enhanced.

  For this reason, when the first load A is applied to the front portion 43 of the side member 8 as described above, the first load A acts on the midway portion 40 of the side member 8 as well. The intermediate portion 40 of the side member 8 that has been countered with a large resistance against the first load A is prevented once from being deformed.

  It is assumed that the collision has progressed and the compression deformation of the front portion 43 of the side member 8 by the first load A is almost completed. Here, as described above, the resistance force of the middle portion 40 of the side member 8 against the first load A is greater than that of the front portion 43. For this reason, when the collision further progresses, the load applied to the middle part 40 of the side member 8 from the front becomes the second load B larger than the first load A. Then, by the second load B, the concave portion 41 is formed, and the middle portion 40 of the side member 8 is bent and deformed toward the inner side C in the width direction of the vehicle body 2 as described above. A predetermined deformation is obtained.

  As a result, when the vehicle 1 collides during forward movement and a load is applied to the vehicle body 2 from the front, the load causes the side member 8 of the vehicle body 2 to move to the front portion 43 and the rear side of the front portion 43. The intermediate portion 40 undergoes predetermined deformation in this order over time. For this reason, a desired energy absorption amount can be obtained by each of the above deformations, and the load can be sufficiently relaxed.

  A part of the second load B is applied to the coupling member 46. Therefore, if the coupling member 46 is slightly compressed or bent by the second load B, the amount of the second load B is increased accordingly. The amount of energy absorption can be increased.

  Further, as described above, the inner surface of the recess 41 is formed so as to go inward in the width direction of the vehicle body 2 as it goes downward as viewed from the line of sight along the longitudinal direction of the vehicle body 2 (FIG. 4).

  For this reason, the upper part in the middle part 40 of the side member 8 can keep the width dimension large, and its strength and rigidity are larger than that of the lower part. Therefore, the upper part of the midway part 40, together with the coupling member 46 and the apron member 37 coupled to the upper part, more strongly opposes the first load A and the second load B, so that the midway part 40 is An attempt to bend in an unintended direction such as upward is more reliably prevented. As a result, the predetermined deformation in the midway portion 40 can be obtained more reliably.

  On the other hand, the width dimension of the lower part of the midway part 40 can be reduced, and its strength and rigidity can be set lower. For this reason, the bending deformation of the midway part 40 due to the second load B is rapidly induced by the lower part of the midway part 40 smoothly starting the deformation. Therefore, the predetermined deformation of the midway part 40 described above can be obtained with good timing.

  Further, as described above, the sub-frames 20 are provided below the side members 8 and attached to the front and rear mounting portions 24 and 26 at the rear portion 23 of the side members 8. When a load is applied from the front side, the load allows the sub-frame 20 to be detached from the rear mounting portion 26 of the side member 8, while a third load D larger than the second load B is applied to the side member 8. When the rear portion 23 of the member 8 is given from the front, the portion 55 of the side member 8 between the concave portion 41 and the front mounting portion 24 is bent and deformed toward the upper direction E. A fragile portion 56 is formed.

  Here, the rear part 23 of the side member 8 is reinforced by the sub-frame 20, whereby the strength and rigidity of the rear part 23 of the side member 8 are higher than those of the midway part 40.

  For this reason, when the second load B is applied to the middle portion 40 of the side member 8 as described above, the second load B also acts on the rear portion 23 of the side member 8 but is reinforced as described above. The rear portion 23 of the side member 8 is opposed to the second load B with a large resistance, and the rear portion 23 is prevented from being deformed.

  It is assumed that the collision progresses and the bending deformation of the midway portion 40 of the side member 8 by the second load B is almost completed. Here, as described above, the resistance force of the rear portion 23 of the side member 8 against the second load B is larger than that of the midway portion 40. For this reason, when the collision further progresses, the load applied to the rear portion 23 of the side member 8 from the front becomes a third load D that is larger than the second load B. Then, by the third load D, the portion 55 of the side member 8 in which the fragile portion 56 is formed is bent and deformed upward E as described above, and the rear portion 23 of the side member 8 has a predetermined deformation. Is obtained.

  Further, as described above, when any load (any one of the first load A, the second load B, and the third load D) is applied to the rear portion 23 of the side member 8 from the front, The subframe 20 is detached from the rear mounting portion 26 of the member 8.

  Specifically, it is assumed that the front side of the rear portion 23 of the side member 8 is compressed and deformed rearward by the application of the third load D. Then, the attachment arms 22 of the subframe 20 are interlocked with this deformation, and the subframe 20 is moved rearward relative to the rear attachment portion 26 of the rear portion 23 of the side member 8. For this reason, a shearing force is applied to the bolt of the fastener 27 in the rear mounting portion 26 based on the third load D.

  Moreover, as described above, due to the presence of the fragile portion 56, the portion 55 of the side member 8 is bent and deformed rearward and upward E based on the third load D. Therefore, in conjunction with this bending deformation, the front mounting portion 24 adjacent to the rear side of the portion 55 is deformed such that the front end side thereof is larger than the rear end side and rotates rearward and upward. . Then, the front portion side of the sub-frame 20 attached to the front attachment portion 24 is moved rearward and upward relative to the rear attachment portion 26.

  Here, as described above, the rear end portion of the subframe main body 21 of the subframe 20 is attached to the rear attachment portion 26 formed on the lower surface of the rear portion 23 of the side member 8, and the rear attachment portion 26 is Together with the rear side of the rear portion 23 of the side member 8, the portion is not easily deformed by each load. For this reason, the mutual attachment portion of the rear attachment portion 26 and the subframe 20 including the fastener 27 is distorted by the rearward upward movement of the front portion side of the subframe 20, and in particular, the fastening portion. The bolt of the tool 27 is simultaneously given a composite force due to a shearing force, a bending force, and a tensile force.

  For this reason, due to the combined force applied to the bolt, a large stress is generated in the bolt, and the bolt is easily broken. Therefore, the subframe 20 can be easily and smoothly detached from the rear mounting portion 26 of the side member 8.

  As described above, the sub-frame 20 can be easily and smoothly detached from the rear mounting portion 26 of the side member 8 based on the third load D, so that the side member 8 based on the third load D can be removed. The bending deformation toward the upper direction E of the portion 55 is smoothly achieved without being inhibited by the subframe 20. Accordingly, the portion 55 of the side member 8 is greatly bent and deformed, and at the same time, the portion 55 is pushed rearward by the third load D, and the bending deformation is smoothly promoted. That is, a predetermined deformation can be more reliably obtained in the rear portion 23 of the side member 8.

  As a result, when the vehicle 1 collides during forward movement and a load is applied to the vehicle body 2 from the front, the load causes the side member 8 of the vehicle body 2 to move to the front portion 43 and the rear side of the front portion 43. The midway part 40 and the rear part 23 on the rear side of the midway part 40 undergo predetermined deformation in this order over time. For this reason, a desired energy absorption amount can be obtained by each of the above deformations, and the load can be sufficiently relaxed.

  On the other hand, as described above, each part of the side member 8 is subjected to predetermined deformation, but the apron member 37 is prevented from being deformed by its own strength and rigidity. For this reason, it is suppressed that the adverse effect based on each said load A, B, D is given with respect to the suspension apparatus 3 supported by this apron member 37 via the suspension tower 38. FIG.

  Although the above is based on the illustrated example, the front portion 43 of the side member 8 may be provided separately from the midway portion 40. Further, a crash box having the same configuration as that of the front portion 43 may be separately attached to the front surface of the front portion 43.

It is a simplified partial top view of a vehicle body front part. It is a fragmentary perspective view of a vehicle body front part. It is the simplified side view which looked at the vehicle body front part from the compartment side. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3.

DESCRIPTION OF SYMBOLS 1 Car 2 Car body 3 Suspension device 4 Front wheel 5 Bracket 6 Engine unit 8 Side member 20 Sub frame 23 Rear part 24 Front mounting part 25 Fastening tool 26 Rear mounting part 27 Fastening tool 37 Apron member 40 Midway part 41 Recessed part 43 Front part 44 Deformation Promotion part 46 Coupling member 51 Reinforcement plate 55 Part 56 Fragile part A 1st load B 2nd load C Inner D 3rd load E Upper S1-S5 Spot welding

Claims (3)

A pair of left and right side members extending in the longitudinal direction of the vehicle body, and an apron member disposed above each side member, the apron member for a front wheel disposed on the outer side of each side member. A recess is formed on the outer surface of the midway portion so as to support the suspension device and avoid contact between the longitudinal midway portion of each side member and the front wheel during steering. In the vehicle body front structure in which a deformation promoting portion is formed in the front portion of the side member so that the front portion of the side member is compressed and deformed when a load is applied,
When a connecting member is provided between the apron member and the middle part of the side member to couple them together, and a second load greater than the first load is applied to the middle part of the side member from the front The middle part is bent and deformed inward in the width direction of the vehicle body ,
The concave portion is formed so as to have a convex arc shape inward in the width direction of the vehicle body in plan view of the vehicle body, and is formed over the entire vertical direction of the middle portion of the side member, and the lower end of the coupling member An automobile body front structure characterized in that an edge portion is formed along the upper edge portion of the concave portion and is coupled to the upper edge portion of the concave portion .   The vehicle body front part structure according to claim 1, wherein the inner surface of the concave portion is formed so as to be directed inward in the width direction of the vehicle body as viewed in a line of sight along the longitudinal direction of the vehicle body. .   A sub-frame is provided below each side member and is attached to the front and rear mounting portions at the rear of these side members. When a load is applied to the rear of the side member from the front, While allowing the sub-frame to be detached from the rear mounting portion of the member, when a third load larger than the second load is applied from the front to the rear portion of the side member, The vehicle body front structure according to claim 1 or 2, wherein a fragile portion is formed in the side member portion so that a portion between the mounting portion and the mounting portion is bent and deformed upward.

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