JP6565291B2 - Shock absorbing member, vehicle body and shock absorbing method - Google Patents

Description

  The present invention relates to an impact absorbing member, a vehicle body, and an impact absorbing method, and more particularly, to an impact absorbing member, an automobile body, and an impact absorbing method for absorbing impact energy at the time of a car collision.

  The mainstream of automobile bodies is a structure that does not have a conventional frame, that is, a monocoque structure. The monocoque structure is formed by joining parts that are assembled into a box shape by normal spot welding after press forming a steel plate. The entire body handles static loads and dynamic loads acting on automobiles.

  Structural members such as side members and side sills that constitute the monoc structure body are required to function as shock absorbing members in the event of a collision. Therefore, these structural members are required to have a performance of absorbing a collision energy at the time of a collision, that is, a so-called shock absorption performance.

  In recent years, there has been a demand for a further improvement in collision safety as well as a reduction in vehicle body weight, which can improve the fuel efficiency of automobiles against the backdrop of protecting the global environment. Therefore, the above structural member is required to be lightweight and have an excellent impact absorbing ability.

FIG. 6 is an explanatory diagram showing an example of a vehicle body 1 having a monocoque structure for an automobile.
As shown in FIG. 6, the above-mentioned side member is in the vehicle front-rear direction regardless of whether the front side member 2 is disposed in the engine compartment 5 or the rear side member 3 is disposed on the lower surface of the rear floor panel 6. In the case of front impact (Front Impact) and rear impact (Rear Impact), the impact load in the axial direction (longitudinal direction) is applied to generate axial crushing deformation and bending deformation. By absorbing the impact energy.

  Further, the side sill 4 is disposed on the vehicle side portion 8 and is subjected to an impact load in a direction perpendicular to the axial direction (longitudinal direction) in the case of a side impact (Side Impact), and is mainly bent at three points. It absorbs impact energy by generating deformation.

  As described above, the various shock absorbing members 2 to 4 of the vehicle body 1 of the automobile absorb impact energy by generating plastic work due to axial crushing deformation (progressive plastic buckling deformation) or bending deformation when an impact load is applied. Thus, it is designed so that the living space of the cabin 9 can be secured.

  In the axial crushing deformation of the crash box 7 or the front side member 2, in order to shorten the buckling wavelength of progressive buckling, a recess having a groove-shaped cross section or a cross-shaped cross section is introduced into a body having a polygonal cross section. Has already been done.

  On the other hand, in the rear side member 3 corresponding to the rear collision, as illustrated in FIG. 6, the rear wheel house inner panel 6-1 connected to both sides in the vehicle width direction of the rear floor panel 6 is projected. In order to avoid this, it has a shape bent in the vehicle width direction.

  For this reason, it is not easy in an actual collision environment to stably generate axial crushing deformation, which is generally a design goal. Therefore, impact energy is absorbed by causing bending deformation in top view (plan view) instead of axial crushing deformation.

  In recent years, the rear side member 3 has also been promoted to be lightweight (for example, plate thickness 1.4⇒1.0 mm) and high strength (tensile strength 590⇒980 MPa). As a result, the deformation mode of the rear side member 3 when an impact load is applied changes, and it is difficult to cause bending deformation at a desired bending point. For this reason, there is a concern about the reduction in the amount of shock energy absorbed by the rear side member 3 that has been reduced in weight and strength as described above.

  Patent Document 1 discloses an invention in which a bead extending in the axial direction of a front side member of an automobile is provided to increase the buckling strength and strength balance during impact bending deformation, thereby reducing the weight of the front side member. Has been.

  Patent Document 2 discloses an invention in which the front side member of an automobile is appropriately bent by subjecting the front side member of an automobile to a strength difference by applying a quenching process, thereby appropriately bending the front side member.

  In Patent Document 3, a plurality of beads are shifted by half a pitch on each of an outer panel and an inner panel that constitute a front side member of an automobile, so that each of the plurality of beads is used as a starting point due to an impact load. An invention for obtaining a high impact energy absorption amount EA by generating the axial crushing deformation is disclosed.

  In Patent Document 4, by arranging optimal beads on the upper and side surfaces of the front side member having a hexagonal cross section, the bellows-like axial crushing deformation is stabilized while increasing the initial buckling load at the time of impact load application. The invention to be generated is disclosed.

  In Patent Document 5, the spot welding position of the main body is shifted by (1/4) pitch according to the positions of a plurality of crush beads arranged in a direction orthogonal to the longitudinal direction of the main body. An invention that stably generates bellows-like axial crushing deformation is disclosed.

  In Patent Document 6, in order to effectively apply an impact load input from a bumper and to generate a stable bellows-like axial crushing deformation, the shape of the crash box has a cross-shaped cross section, and the bumper ridge portion is formed. An invention for wrapping around by a protrusion of a crash box is disclosed.

  Furthermore, in Patent Document 7, in the truck chassis offset frame, in order to increase the collision energy absorption amount EA, the stress concentration at the offset portion, which is the starting point of bending at the time of impact load loading, is alleviated to suppress Z-shaped folding. Thus, an invention for generating a bellows-like axial crushing deformation is disclosed.

JP-A-8-108863 International Publication No. 2012/108282 Pamphlet Japanese Patent No. 2795010 Japanese Patent No. 3598917 JP 2012-218503 A Japanese Patent No. 512528 JP 2000-289646 A

  In any of Patent Documents 1 to 7, when a side member formed and assembled from a high-tensile steel plate having a tensile strength of 980 MPa or more is subjected to a collision load in the axial direction, the side members alternate in the axial direction. The shape having a high deformation stability with respect to the load direction of the impact load can be minimized, and the bending moment generated at the rear end portion can be minimized by bending in a plan view and causing an N-shaped bending deformation in plan view. There is no suggestion.

  The present invention has been made in view of such problems of the prior art, and even when formed and assembled using a super-high tensile steel sheet having a tensile strength of 980 MPa or more as a material, in the event of a vehicle collision, (A) Stable collision energy absorption performance is demonstrated regardless of the input direction of the impact load, and N-shaped bending deformation can be stably generated in plan view according to the design target. (B) Deformation in the load input direction Robustness is high, and (c) collision energy absorption capacity does not drop (fluctuate) suddenly due to excessive breakage, and (d) local plastic deformation at the mounting part without generating a high bending moment at the mounting part. Impact absorbing member capable of efficiently absorbing impact energy without occurring, automobile body equipped with the impact absorbing member as a component, and impact absorbing method using the impact absorbing member To provide.

  In order to solve the above-mentioned problems, the present inventors have a specific cross section (a top plate having two first ridge lines extending in the direction of the cross-sectional axis, two curved second ridge lines connected to the top board, and these A substantially hexagonal cross having two vertical walls respectively connected to the two second ridge lines, two concave ridge lines connected to the two vertical walls, and two outward flanges connected to the two concave ridge lines, respectively. When an impact absorbing member (for example, a side member) having an axially extending surface is loaded with an impact load in the axial direction, the N-shaped bending deformation in a plan view in a direction intersecting the top plate As a result of diligent examination of the occurrence state, the following knowledge A to C was obtained, and the present invention was completed.

  (A) At least two recesses formed between the two second ridge lines to the vertical walls so as to be substantially orthogonal to the axial direction of the shock absorbing member are separated from each other in the axial direction of the two vertical walls. The above-mentioned problem can be solved by preparing for the place.

  (B) In order to solve the above problem, the width wb (mm) of the recess satisfies the relationship of 0.3 × h ≦ wb ≦ 0.6 × h with respect to the height h (mm) of the vertical wall. It is preferable.

  (C) It is more preferable that any of the concave portions pass through the two second vertical walls and reach the two concave ridge lines.

The present invention is listed below.
(1) An impact-absorbing member that includes a press-formed body of a high-tensile steel sheet having a tensile strength of 980 MPa or more and absorbs an impact load applied in the axial direction,
The press-formed body includes a top plate having two first ridge lines extending in the axial direction, two second ridge lines connected to the top plate, and two vertical walls connected to the two second ridge lines, respectively. , Two concave ridge lines respectively connected to the two vertical walls, and two outward flanges respectively connected to the two concave ridge lines,
A shock absorbing member comprising recesses that reach the vertical wall from the second ridge line and are substantially orthogonal to the axial direction at at least two locations apart from each other in the axial direction of the two vertical walls. .

  (2) The at least two concave portions are opposite to each other with respect to the direction in the plan view in a direction intersecting the top plate when an impact load is applied in the axial direction. 2. The impact absorbing member according to item 1, which is a deformation starting point of an N-shaped bending deformation caused by bending.

  (3) The impact absorbing member according to item 1 or 2, wherein the at least two recesses divide the second ridge line in the axial direction.

(4) The width (wb) of the concave portion and the height (h) of the vertical wall satisfy a relationship of 0.3 × h (mm) ≦ wb (mm) ≦ 0.6 × h (mm). 4. The impact absorbing member according to any one of items 1 to 3.
However, the width wb of the concave portion means a length of the opening of the concave portion on the extension of the second ridge line in a plan view in a direction intersecting the top plate, and the height h of the vertical wall is the vertical wall. This means the length in the height direction.

  (5) The impact absorbing member according to any one of items 1 to 4, wherein the at least two concave portions pass through the vertical wall and reach the concave ridge line.

  (6) The impact absorbing member according to any one of items 1 to 5, which is an impact absorbing member for an automobile body.

  (7) The impact absorbing member according to item 6, which is a side member.

  (8) The impact absorbing member according to item 7, wherein the side member is a rear side member.

  (9) An automobile body comprising the shock absorbing member described in any one of items 6 to 8 as a component of the body shell.

  (10) The impact absorbing member described in any one of items 6 to 8 is disposed at a predetermined position of the vehicle body as a component of the body shell, and at least two of the at least two in the event of a collision An impact absorbing method characterized in that impact energy is absorbed by causing an N-shaped bending deformation in a plan view in a direction intersecting the top plate starting from a recess.

  Even if the impact absorbing member of the present invention is formed and assembled using a super high strength steel plate having a tensile strength of 980 MPa or more as a raw material, N Characteristic bending deformation can be stably generated as designed, and as a result, stable collision energy absorption performance can be exhibited. That is, the robustness of deformation in the load input direction is high, the collision energy absorption capacity does not change due to excessive breakage, and local plastic deformation does not occur in the mounting part without generating a high bending moment in the mounting part. For example, an impact absorbing member such as a side member (particularly, a rear side member) of an automobile that can efficiently absorb impact energy can be provided.

FIG. 1 is an explanatory view showing a rear side member which is an impact absorbing member according to the present invention. FIG. 1A shows a state before an impact load is applied. FIG. 1B shows a state after an impact load is applied and an N-shaped bending deformation occurs in a plan view. FIG. 2 is an explanatory view showing the deformation state of the rear side member at this time with time. FIG. 3 is a press-formed body of a high-strength steel plate having a tensile strength of 980 MPa or more and a plate thickness of 1.2 mm. The rear side member of the present invention shown in FIG. It is explanatory drawing which shows the influence of the shape of the recessed part which acts on this. FIG. 3A is a top view showing the concave portion. 3B shows a case where Wb = 45 mm and db = 20 mm. FIG. 3C shows a case where Wb = 68 mm and db = 20 mm. FIG. 3D shows a case where Wb = 124 mm and db = 20 mm. (E) shows the shape of each rear side member after impact loading when Wb = 45 mm and db = 10 mm. FIG. 4 is a graph showing the relationship between the crushing stroke (displacement of the rigid wall) in the axial direction and the load for the four types of rear side members shown in FIGS. 3 (b) to 3 (e). FIG. 5 shows a history of the bending moment of the rear end portion generated when the rigid wall collides in the member axial direction. FIG. 5A is a graph showing a bending moment history of a rear side member of a comparative example in which a convex portion is provided instead of the concave portion of FIG. FIG.5 (b) is a graph which shows the bending moment log | history of the rear-end part in the rear side member of the example of this invention which provided the recessed part. FIG. 6 is an explanatory view showing an example of a vehicle body of a monocoque structure of an automobile.

  The present invention will be described with reference to the accompanying drawings. In the following description, as shown in FIG. 6, the shock absorbing member 10 according to the present invention is a component of the vehicle body 1 of a monocoque body of an automobile and is arranged on the rear side of the rear floor panel 6. Take the case of member 3 as an example. However, the present invention is not limited to the rear side member 3 and can be similarly applied to, for example, the front side member 2 and the side sill 4.

1. Rear side member 10
FIG. 1 is an explanatory view showing a rear side member 10 which is an impact absorbing member according to the present invention. FIG. 1 (a) shows a state before an impact load is applied, and FIG. 1 (b) shows an impact load. Is a state after N-shaped bending deformation is caused in a plan view. FIG. 1B shows a state where the rear side member 10 is mounted on the rear floor panel 6.

  The rear side member 10 is a press-formed body of a high-tensile steel plate having a tensile strength of 980 MPa or more, preferably 1180 MPa or more, and more preferably 1380 MPa or more.

  The plate thickness of the high-tensile steel plate is preferably about 0.8 to 2.0 mm when the tensile strength is 980 MPa or more, and about 0.8 to 1.6 mm when the tensile strength is 1180 MPa or more. Further, when the tensile strength is 1380 MPa or more, it is about 0.6 to 1.4 mm.

  The rear side member 10 has a substantially hexagonal cross-sectional shape. That is, the cross-sectional shape is such that the top plate 11 having two first ridge lines 12-1a and 12-1b extending in the axial direction, two second ridge lines 12-2a and 12-2b, and two vertical lines. The walls 13a and 13b, two concave ridge lines 14a and 14b, and two outward flanges 15a and 15b are formed.

  The top plate 11 is partitioned by one top surface 11-1 defined by the first ridgelines 12-1a and 12-1b, and by the first ridgeline 12-1a and the second ridgeline 12-2a. A slope 11- formed by connecting to the top surface 11-1 while being partitioned by the slope 11-2 connected to the surface 11-1 and the first ridgeline 12-1b and the second ridgeline 12-2b. 3.

  Thus, the rear side member 10 has a substantially hexagonal shape constituted by the first ridge lines 12-1a and 12-1b, the second ridge lines 12-2a and 12-2b, and the concave ridge lines 14a and 14b. It has a cross-sectional shape extending in the axial direction (in the direction of the double arrow in FIG. 1A and meaning the longitudinal direction of the rear side member 10).

  The two second ridgelines 12-2a and 12-2b are formed to be connected to the edges of the slopes 11-2 and 11-3 and are curved with a predetermined radius of curvature.

  The two vertical walls 13a and 13b are formed to be connected to the two second ridge lines 12-2a and 12-2b, respectively.

  The two concave ridge lines 14a and 14b are formed to be connected to the two vertical walls 13a and 13b, respectively.

  Further, the two outward flanges 15a and 15b are formed to be connected to the two concave ridge lines 14a and 14b, respectively.

  The rear side member 10 includes recesses 16 and 17. The recesses 16 and 17 are both recesses that protrude toward the inner side of the substantially hexagonal cross section. The recesses 16 and 17 are both formed from the second ridge lines 12-2a and 12-2b through the vertical walls 13a and 13b to reach the recessed ridge lines 14a and 14b and substantially orthogonal to the axial direction. The recesses 16 and 17 do not need to reach the concave ridge lines 14a and 14b, but by reaching the concave ridge lines 14a and 14b, N-shaped bending deformation can be more stably generated in a plan view.

  The concave portions 16 and 17 need to be convex toward the inner side of the substantially hexagonal cross section. As a result, the outward flanges 15a and 15b collapse in the cross-sectional height direction without generating a high bending moment in the two outward flanges 15a and 15b, which are the attachment portions of the rear side member 10, so that N Generates a bending deformation in the shape of a letter and can efficiently absorb impact energy.

  The recesses 16 and 17 are formed in at least two places separated from each other in the axial direction of the two vertical walls 13a and 13b. The recesses 16 and 17 are preferably formed by dividing the second ridge lines 12-2a and 12-2b in the axial direction.

  Furthermore, it is preferable that the recessed parts 16 and 17 are formed so that the concave ridgelines 14a and 14b may also be divided in the axial direction. This is because N-shaped bending deformation can be more stably generated in a plan view.

  The distance in the axial direction between the concave portion 16 and the concave portion 17 may be appropriately set according to the N-shaped bending deformation mode in plan view to be generated. For example, the distance is about 100 to 450 mm. The recesses 16 and 17 are preferably arranged at two locations that divide the entire length of the rear side member 10 into approximately three equal parts.

  The width wb (mm) of the recesses 16 and 17 and the height (h) of the vertical walls 13a and 13b have a relationship of 0.3 × h (mm) ≦ wb (mm) ≦ 0.6 × h (mm). It is preferable to satisfy. This is because an N-shaped bending deformation is surely generated in a plan view.

  When the width Wb <0.3 × h of the recesses 16 and 17, the amount of deformation (wrinkle size) inside the cross section caused by the bending deformation in the recesses 16 and 17 is small, in other words, the bending stroke is shortened. Therefore, it may be difficult to generate a stable N-shaped bending deformation.

  On the other hand, when the width Wb> 0.6 × h of the recesses 16 and 17 is reached, the bending stroke becomes excessively long, and the low load region accompanying bending deformation becomes long, so that efficient collision energy absorption cannot be achieved. Sometimes.

  Here, the width wb of the recesses 16 and 17 means the length of the openings of the recesses 16 and 17 on the extension of the second ridge lines 12-2a and 12-2b in a plan view in the direction intersecting the top plate 11. The height h of the vertical walls 13a and 13b means the length of the vertical walls 13a and 13b in the height direction.

  As shown in FIG. 1B, each of the two recesses 16 and 17 is N in a plan view generated by bending in the axial direction opposite to each other when an impact load is applied in the axial direction. It becomes the deformation starting point of the letter-shaped bending deformation.

  In addition, in the rear side member 10 shown to Fig.1 (a), although the cross-sectional shape of the recessed parts 16 and 17 was made into the semicircle, it is not limited to a semicircle. For example, the shape may be an ellipse, an oval, a part of a polygon, or a shape obtained by appropriately combining these shapes. Preferably, the cross sections of the recesses 16 and 17 are concave curves. As described above, the concave portions 16 and 17 need to be a starting point for generating a concave bending deformation stably by an axial load generated on the member and generating an N-shaped overall bending deformation. Therefore, in order to be the starting point of bending in the entire recesses 16 and 17, there is no sudden shape change that becomes the starting point of local deformation, and a smooth curved shape is preferable.

  That is, the cross-sectional shape of the recesses 16 and 17 is not particularly limited. The recessed parts 16 and 17 should just be formed so that the 2nd ridgeline 12-2a and 12-2b may be parted about an axial direction. Preferably, the concave portions 16 and 17 are formed so as to divide the concave ridge lines 14a and 14b in the axial direction.

  Although not shown in FIG. 1 (a), the rear side member 10 projects the rear wheel house inner panel 7 connected to both sides of the rear floor panel 6 in the vehicle width direction as shown in FIG. In order to avoid it, it has a shape bent in the vehicle width direction.

The rear side member 10 is configured as described above.
The rear side member 10 is manufactured by a known press working method such as a known press working method by bending using a punch and a die or a known press working method by drawing using a punch, a blank holder and a die. However, when the shapes of the recesses 16 and 17 are large, wrinkles on the top plate 11 are slightly increased. Therefore, drawing forming in which tension acts on the vertical walls 13a and 13b is preferable to bending forming.

2. Vehicle Body Comprising Rear Side Member 10 As described above, the vehicle body according to the present invention includes the rear side member 10 as a component of the body shell. The rear side member 10 is welded and fixed to the lower surface 6a of the rear floor panel 6 by, for example, resistance spot welding via the back surfaces (surfaces away from the top plate 11) of the two outward flanges 15a and 15b. The rear side member 10 is arranged in the front-rear direction of the vehicle, and is subjected to an impact load in the axial direction (longitudinal direction) at the time of rear impact, and is mainly N-shaped in plan view. The impact energy is absorbed by generating a bending deformation of the shape.

3. Impact Energy Absorbing Method Using Rear Side Member 10 The vehicle body according to the present invention absorbs impact energy that is input by the rear side member 10 during a rear impact.

FIG. 2 is an explanatory view showing the deformation state of the rear side member 10 at this time with time.
That is, the rear side member 10 is used as a component of the body shell, and a predetermined position (rear floor panel 6) of the vehicle body via the back surfaces (surfaces away from the top plate 11) of the two outward flanges 15a and 15b. Are fixedly arranged by welding, for example, by resistance spot welding in the vehicle front-rear direction.

  In the event of a collision, the impact energy is absorbed by causing N-shaped bending deformation in plan view starting from the recesses 16 and 17.

The present invention will be described more specifically with reference to examples.
FIG. 3 is a press-formed body of a high-tensile steel plate having a tensile strength of 980 MPa or more and a plate thickness of 1.2 mm. The rear side member 10 of the present invention shown in FIG. It is explanatory drawing which shows the influence of the shape of the recessed part 16 and 17 which acts on a behavior. FIG. 3A is a top view showing the recesses 16 and 17. 3B shows a case where Wb = 45 mm and db = 20 mm. FIG. 3C shows a case where Wb = 68 mm and db = 20 mm. FIG. 3D shows a case where Wb = 124 mm and db = 20 mm. (E) shows the shape of each rear side member after impact loading when Wb = 45 mm and db = 10 mm.

  Here, as shown in FIG. 3 (a), the width Wb of the recess means the length of the opening of the recesses 16 and 17 on the extension of the second ridge line in a plan view in the direction intersecting the top plate, The depth db of the recess means the maximum depth of the openings of the recesses 16 and 17 in a plan view in a direction intersecting the top plate.

  FIG. 4 is a graph showing the relationship between the crushing stroke (displacement of the rigid wall) in the axial direction and the load for the four types of rear side members 10 shown in FIGS. 3 (b) to 3 (e).

  It can be seen from the graph shown in FIG. 4 that the rear side member 10 is reliably bent and deformed in an N shape in plan view by the two concave portions 16 and 17 provided in the axial direction. For this reason, the rear side member 10 according to the present invention is more resistant to changes in the input direction of the impact load from the axial direction than the conventional rear side member that absorbs the impact energy by the bellows-shaped axial crushing deformation ( Deformation robustness) can be improved.

  Further, from the graph shown in FIG. 4, even if the rear side member 10 is formed of a thin steel plate having a tensile strength of 980 MPa, N-shaped bending deformation is surely generated in plan view starting from the two recesses 16 and 17. It was shown that

  For this reason, the bending curvature radius of the bending deformation of the rear side member 10 is larger than the bending wrinkle of the conventional bellows-shaped buckling deformation in the conventional rear-side member that absorbs impact energy by the bellows-shaped axial crushing deformation. Even a material with poor ductility, such as a thin steel plate with a tensile strength of 980 MPa, is not easily broken during bending deformation, and a high impact energy absorption amount can be obtained.

  FIG. 5 shows a history of the bending moment of the rear end portion generated when the rigid wall collides in the member axial direction. FIG. 5A is a graph showing a bending moment history of the rear side member 20 of the comparative example in which the convex portions 18 and 19 are provided instead of the concave portions 16 and 17 of FIG. FIG. 5B is a graph showing the bending moment history of the rear end portion of the rear side member 10 according to the present invention in which the concave portions 16 and 17 are provided.

  From the graphs of FIGS. 5A and 5B, the rear side member 20 of the comparative example provided with the convex portions 18 and 19 is compared with the rear side member 10 of the present invention example provided with the concave portions 16 and 17. It can be seen that a high y-direction moment is generated at the initial stage of deformation when the displacement d of the rigid wall is about 10 mm and when the displacement d exceeds 150 mm.

  That is, in the rear side member 20 of the comparative example in which the convex portions 18 and 19 are provided, other members coupled to the rear side member 20 are bent to plastically deform the coupled portion. On the other hand, in the rear side member 10 of the present invention provided with the recesses 16 and 17, the bending deformation of other members (attachment portions) coupled to the rear side member 10 can be suppressed, and as a result, the impact energy Can be absorbed efficiently.

DESCRIPTION OF SYMBOLS 10 Rear side member 11 Top plate 12-1a, 12-1b 1st ridgeline 12-2a, 12-2b 2nd ridgeline 13a, 13b Vertical wall 14a, 14b Concave ridgeline 15a, 15b Outward flange 16, 17 Recess

Claims (10)

An impact-absorbing member comprising a press-formed body of a high-tensile steel plate having a tensile strength of 980 MPa or more, and absorbing an impact load applied in the axial direction,
The press-formed body includes a top plate having two first ridge lines extending in the axial direction, two second ridge lines connected to the top plate, and two vertical walls connected to the two second ridge lines, respectively. , Two concave ridge lines respectively connected to the two vertical walls, and two outward flanges respectively connected to the two concave ridge lines,
Recesses that reach the vertical wall from the second ridge line and that are substantially orthogonal to the axial direction are provided at at least two locations apart from each other in the axial direction of the two vertical walls ,
The shock absorbing member satisfying a relationship of 0.3 × h (mm) ≦ wb (mm) ≦ 0.6 × h (mm) between the width (wb) of the recess and the height (h) of the vertical wall .
However, the width wb of the concave portion means a length of the opening of the concave portion on the extension of the second ridge line in a plan view in a direction intersecting the top plate, and the height h of the vertical wall is the vertical wall. This means the length in the height direction.   When the impact load is applied in the axial direction, the at least two recesses are bent in opposite directions with respect to the direction in the plan view in a direction intersecting the top plate. The shock absorbing member according to claim 1, wherein the shock absorbing member is a deformation starting point of an N-shaped bending deformation caused by the above.   The impact absorbing member according to claim 1 or 2, wherein the at least two concave portions divide the second ridge line in the axial direction. The high-tensile steel plate has a tensile strength of 980 MPa to less than 1180 MPa and a plate thickness of 0.8 to 2.0 mm, a tensile strength of 1180 MPa to less than 1380 MPa, and a plate thickness of 0.8 to 1.6 mm. The shock absorption according to any one of claims 1 to 3 , wherein the steel sheet is a steel plate or a steel plate having a tensile strength of 1380 MPa or more and a thickness of 0.6 to 1.4 mm. Member .   The impact absorbing member according to any one of claims 1 to 4, wherein the at least two concave portions pass through the vertical wall and reach the concave ridge line.   The impact absorbing member according to any one of claims 1 to 5, which is an impact absorbing member for an automobile body.   The impact absorbing member according to claim 6, wherein the impact absorbing member is a side member.   The impact absorbing member according to claim 7, wherein the side member is a rear side member.   An automobile body comprising the impact absorbing member according to any one of claims 6 to 8 as a component of the body shell.   The impact absorbing member according to any one of claims 6 to 8 is disposed at a predetermined position of an automobile body as a component of a body shell, and the at least two recesses are provided at the time of a collision accident. A shock absorbing method characterized by absorbing impact energy by generating an N-shaped bending deformation in a plan view in a direction intersecting the top plate starting from.

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