JP2018154294A - Vehicle body front structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle body front structure in which an off-set front collision is considered so that the amount of overlapping is reduced.SOLUTION: A sub-frame 50 extending from a suspension cross member 27 to the vehicle body front side is provided at a position lower than a side member 20. The sub-frame 50 includes a sub-frame main body 52 and a load transmission member 70 provided at a front end portion of the sub-frame main body 52. The load transmission member 70 is protruded outward of a vehicle body outer surface of the side member 20. A deformation control portion 130 is formed by a portion of the sub-frame main body 52 in a longitudinal direction thereof to be located at the rear side of the load transmission member 70. A cross-section along the vehicle body width direction of the deformation control portion 130 is formed in a cross-sectional shape deformable in a direction in which the deformation control portion 130 is brought into interference with a power plant 38 when a collision load input from the front side of the load transmission member 70 is transmitted to the deformation control portion 130.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vehicle body front structure that constitutes a front portion of a vehicle, and more particularly to a vehicle body front structure that takes into account an offset collision with a small overlap amount.

  A vehicle body front structure for protecting an occupant has been proposed on the assumption that a collision load is input to the vehicle. A frontal collision of a vehicle includes an offset collision with a small overlap amount (referred to as a small overlap collision) in which a colliding object moves from the front along the outer surface of the side member of the own vehicle. In the case of such a collision mode, the collision partner cannot be received by the side member that is a skeleton member, and therefore, the collision partner may enter the cabin (vehicle compartment) side.

  For example, as described in Patent Document 1, a vehicle body front structure has been proposed in which a gusset is provided on the surface of the side member on the outer side of the vehicle body, and a collision load is transmitted to the side member by this gusset. Alternatively, as shown in Patent Document 2, a vehicle body front structure in which a gusset is provided between an end portion of a bumper beam and a side member and a collision load is transmitted to the side member by the gusset is proposed. In the vehicle body front structure disclosed in Patent Documents 1 and 2, the side members are bent and deformed by a collision load, and the engine is pressed to keep the vehicle bodies apart and protect the cabin.

Japanese Patent Laid-Open No. 2015-137080 JP2015-189408A

  In the case of the configuration in which the collision load is transmitted to the side member and deformed in the direction of pressing the engine as in Patent Documents 1 and 2, for example, a small vehicle in which a vehicle with a high vehicle height and a vehicle with a low vehicle height collide with each other from the front direction. During the overlap collision, the vehicle with the higher vehicle height may not collide with the side member and may not be deformed in the direction in which the side member presses the engine.

  Therefore, according to the present invention, even in the case of an offset collision with a small overlap rate and a collision partner colliding from a position lower than that of the side member, the front part of the vehicle body is moved away from the collision partner. It is in providing the vehicle body front part structure which can do.

  A vehicle body front structure according to an embodiment includes a vehicle body front structure including a side member extending in the front-rear direction of the vehicle body and a suspension cross member disposed at a position lower than the side member and extending in the width direction of the vehicle body. A sub-frame body disposed at a position lower than the side member and extending from the suspension cross member toward the front of the vehicle body; and a load transmission member provided at a front end portion of the sub-frame body. Yes. The load transmission member has a front end protruding outward from the outer surface of the side member of the side member, and a hypotenuse that approaches the subframe body from the front end toward the rear end. Further, a deformation control unit is formed in a part of the subframe main body in the longitudinal direction. The deformation control unit is formed on the rear side of the rear end of the load transmission member, and is pushed by the load transmission member when a load from the front of the vehicle body is input to the load transmission member. The cross-sectional shape is deformable in a direction that interferes with an object.

  An example of the load transmission member is a triangle having a front end that protrudes to the outside of the vehicle body from the surface of the side member outside the vehicle body when viewed from above, and the hypotenuse extending from the front end to the rear of the vehicle body. The rear end of the member is connected to the front side of the deformation control unit. In addition, the example of the deformation control unit has a constricted portion that is recessed toward the inside of the vehicle body on a part of the vehicle body outside in the longitudinal direction of the subframe body.

  The deformation control unit relates to a cross section along the vehicle body width direction from the outer lower side of the vehicle body to the inner upper side of the vehicle body, compared with a section coefficient around the first axis from the upper outer side of the vehicle body to the lower inner side of the vehicle body. The section modulus around the second axis toward may be large. Further, the sub-frame body has a lower panel member and an upper panel member, and the lower panel member has a ridge line portion located on the second axis in a cross section along the vehicle body width direction of the deformation control unit. The upper panel member may have an upper surface wall having a shape inclined from the outer upper side of the vehicle body toward the inner lower side of the vehicle body on the second axis in the cross section. The deformation control unit may have a first flange protruding to the inside of the vehicle body, or the deformation control unit may have a second flange protruding upward.

  According to the vehicle body front structure of the present invention, when the collision object is an offset collision with a small overlap rate, the collision object collides from a position lower than the side member along the outer surface of the side member from the front of the vehicle. In addition, the collision load input to the load transmitting member is transmitted to the deformation control unit, and the deformation control unit is deformed in a direction that interferes with a rigid structure (for example, a power plant) in the engine room. It is possible to move in a direction away from the vehicle (vehicle width direction).

The top view of a part of vehicle body provided with the vehicle body front part structure which concerns on one embodiment. FIG. 2 is a side view of a part of the vehicle body shown in FIG. 1. The front view which looked at a part of vehicle body shown by FIG. 1 from the front. The top view which looked at a part of vehicle body shown by FIG. 1 from upper direction. FIG. 2 is a perspective view of a subframe that forms a part of the vehicle body shown in FIG. 1. FIG. 6 is an exploded perspective view of the subframe shown in FIG. 5. FIG. 6 is a plan view of the subframe shown in FIG. 5. Sectional drawing of the sub-frame in alignment with the F8-F8 line | wire in FIG. Sectional drawing which shows the cross section of the sub-frame in alignment with F9-F9 line in FIG. 7, and a power plant.

  Hereinafter, a vehicle 10 including a vehicle body front part structure according to one embodiment will be described with reference to FIGS. 1 to 9. FIG. 1 is a plan view schematically showing a skeleton member and the like constituting a front portion (referred to as a vehicle body front portion 11 a) of a vehicle body 11 of the vehicle 10. FIG. 2 is a side view of the vehicle body front portion 11a. 3 is a front view of a part of the vehicle body front part 11a, and FIG. 4 is a plan view of a part of the vehicle body front part 11a as viewed from above.

  As shown in FIG. 1, the vehicle body 11 includes a pair of side members 20 and 21. The side members 20 and 21 are examples of frame members that form the skeleton of the vehicle body, and extend in the front-rear direction of the vehicle body 11 (the front-rear direction of the vehicle 10). The arrow X1 in FIGS. 1, 5 and 7 indicates the front of the vehicle body, and the arrow X2 indicates the rear of the vehicle body. An arrow Y in FIG. 1 indicates the width direction of the vehicle body. 3, 5, 7, and 8, the arrow Z <b> 1 indicates the vehicle body outside, and the arrow Z <b> 2 indicates the vehicle body inside.

  As shown in FIG. 2, a bumper beam 26 is provided via a plate 22 and a crush can 23 provided on the front end side of the side members 20, 21. A suspension cross member 27 extending in the width direction of the vehicle body is disposed below the side members 20 and 21. One end 27a and the other end 27b of the suspension cross member 27 are fixed to the side members 20 and 21 via connecting members 28 (only one is shown in FIG. 2), respectively.

  Suspension arms 30 and 31 forming a part of the front suspension are provided at one end 27a and the other end 27b of the suspension cross member 27 in the vehicle body width direction, respectively. The suspension arms 30 and 31 are supported so as to be swingable in the vertical direction with respect to the side members 20 and 21. The suspension arms 30 and 31 support the front wheels 32 and 33 via knuckle members, respectively.

  Side sills 34 and 35 (shown in FIG. 1) are provided along the side members 20 and 21 at the lower portion of the vehicle body 11. A cabin (vehicle compartment) 36 for an occupant is formed above the floor member disposed on the floor between the side sills 34 and 35. An engine room 37 is formed in front of the cabin 36. In the engine room 37, a power plant 38 and other structures necessary for traveling are arranged. A steering wheel 39 is disposed at a cockpit in the cabin 36.

  Brackets 40 and 41 are fixed to the lower surfaces of the front end portions of the side members 20 and 21, respectively. A first subframe 50 is provided between one bracket 40 and one end 27 a of the suspension cross member 27. A second subframe 51 is provided between the other bracket 41 and the other end 27 b of the suspension cross member 27. A front end cross member 25 extending in the width direction of the vehicle body is provided between the front end portions of the sub frames 50 and 51.

The configuration and operation of one subframe 50 will be described below.
5 is a perspective view of the subframe 50, FIG. 6 is an exploded perspective view of the subframe 50, and FIG. As shown in FIG. 6 and the like, the subframe 50 includes a lower panel member 60, a lower reinforcement member 61, an upper reinforcement member 62, an upper panel member 63, and a load transmission that constitute the subframe main body 52. Member 70. Each of these members is, for example, a sheet metal press-formed product. The load transmission member 70 includes a first member 71 and a second member 72.

  By joining the lower panel member 60, the lower reinforcement member 61, the upper reinforcement member 62, and the upper panel member 63 by spot welding or the like at appropriate positions, four members 60, 61, A sub-frame main body 52 having a laminated structure composed of 62 and 63 is formed. The subframe main body 52 has a front end 52a (shown in FIG. 7) located on the front side of the vehicle body and a rear end 52b located on the rear side of the vehicle body. A load transmitting member 70 is fixed to the outer surface of the vehicle body at the front end of the subframe main body 52 by welding. The load transmission member 70 will be described in detail later.

  The lower panel member 60 includes a bottom wall 60a and a flange portion 60b that rises from the side of the bottom wall 60a outside the vehicle body. At the rear end portion of the bottom wall 60a, holes 84 and 85 are formed in which cylinder portions 82 and 83 into which bolts 80 and 81 (shown in FIG. 5) are inserted are arranged. A hole 87 for inserting a bolt 86 (shown in FIG. 5) is formed at the front end of the bottom wall 60a. Holes 90 and 91 for inserting bolts 88 and 89 (shown in FIG. 5) are formed in the flange portion 60b.

  The lower reinforcement member 61 includes a first reinforcing portion 61a that overlaps the upper surface of the bottom wall 60a of the lower panel member 60, and a first flange reinforcing portion 61b that overlaps the flange portion 60b of the lower panel member 60. doing. As shown in FIG. 7, the lower reinforcement member 61 is provided from the rear end 52b of the subframe main body 52 over the length L1.

  The upper reinforcement member 62 includes a second reinforcement portion 62 a that overlaps the upper surface of the first reinforcement portion 61 a of the lower reinforcement member 61 and a second reinforcement portion 61 b that overlaps the first flange reinforcement portion 61 b of the lower reinforcement member 61. Flange reinforcing portion 62b. As shown in FIG. 7, the upper reinforcement member 62 is provided from the rear end 52b of the subframe main body 52 over the length L2. The length L2 of the upper reinforcement member 62 is smaller than the length L1 of the lower reinforcement member 61.

  The upper panel member 63 includes an upper surface wall 63a having a length equivalent to the bottom wall 60a of the lower panel member 60, and a flange portion 63b that rises from the side of the upper surface wall 63a outside the vehicle body. The upper surface wall 63 a includes a rear half portion 63 c that overlaps the upper reinforcement member 62 and a front half portion 63 d that overlaps the lower panel member 60. Holes 95 and 96 are formed at positions corresponding to the holes 84 and 85 of the lower panel member 60 at the rear end portion of the upper surface wall 63a. A hole 97 is formed at a position corresponding to the hole 87 of the lower panel member 60 at the front end portion of the upper surface wall 63a. Holes 98 and 99 are formed in the flange portion 63b at positions corresponding to the holes 90 and 91 of the lower panel member 60.

  The load transmitting member 70 is formed so that the first member 71 and the second member 72 are coupled to each other so that the shape viewed from above is substantially a triangle. The front end 70a of the load transmitting member 70 projects outward from the outer surface of the side member 20 on the vehicle body. The first member 71 includes an upper plate portion 100 and a lower plate portion 101 that are substantially triangular when viewed from above, a first oblique side portion 102 that connects the upper plate portion 100 and the lower plate portion 101 to each other, and an upper plate portion 100. And a bent edge portion 103 formed on the surface.

  The second member 72 includes a second oblique side portion 110 along the first oblique side portion 102, an end plate portion 111 extending from the front end of the second oblique side portion 110 toward the vehicle body inside, and the second oblique side portion 110. And an extension 112 extending rearward from the rear end. As shown in FIG. 8, the first member 71 and the second member 72 are fixed to each other by the welded portion 120 or the like, so that a highly rigid load transmission member 70 composed of the first member 71 and the second member 72 is configured. ing.

  FIG. 8 shows a cross section along the vehicle body width direction of the subframe 50 taken along line F8-F8 in FIG. As shown in FIG. 8, the bent edge portion 103 of the first member 71 is fixed to the flange portion 60b of the lower panel member 60 by the welded portion 121 or the like. The tip of the lower plate portion 101 of the first member 71 is fixed to the bottom wall 60a of the lower panel member 60 by the welded portion 122 or the like. Further, the extension 112 of the second member 72 is welded to the flange 60b of the lower panel member 60. The load transmitting member 70 is fixed to the subframe main body 52 in this manner, whereby a subframe (also referred to as a subframe assembly) 50 is configured.

  The subframe 50 is attached to the vehicle body 11 by fixing the rear end side of the subframe 50 to the suspension cross member 27 with bolts 80 and 81 (shown in FIG. 5), and the front end side of the subframe 50 with bolts 86 and 88. , 89 (shown in FIG. 5) to the bracket 40 on the lower surface of the side member 20.

  FIG. 9 schematically shows a cross section of the subframe 50 taken along line F9-F9 in FIG. 7 and a part of a power plant 38 that is an example of a structure disposed in the engine room 37. The power plant 38 includes a drive system such as an engine and a transmission, and is relatively rigid and substantially rigid. FIG. 9 shows, as an example of the structure, an engine that forms part of the power plant 38, a part of the transmission 38a, and a part of the oil pan 38b. As shown in FIG. 9, the subframe main body 52 has a first flange FL <b> 1 protruding in the horizontal direction toward the power plant 38 and a second flange FL <b> 2 protruding upward.

  The subframe 50 according to the present embodiment includes a deformation control unit 130 at an intermediate portion in the longitudinal direction of the subframe main body 52 (between the front end 52a and the rear end 52b). An example of the deformation control unit 130 includes a constricted portion 131 formed on the outer surface of the vehicle body at the intermediate portion in the longitudinal direction of the subframe main body 52. The deformation control unit 130 is formed on the rear side of the rear end 70 b of the load transmission member 70.

  As shown in FIG. 7, when the subframe 50 is viewed from above, the constricted portion 131 has a concave curved surface 132 having a shape in which the outer surface of the vehicle body at the intermediate portion in the longitudinal direction of the subframe 50 is recessed toward the inner side of the vehicle body. . In the constricted portion 131 having such a concave curved surface 132, the front end portion 32a of the front wheel 32 interferes with the subframe 50 in a state where the steering angle of the front wheel 32 is maximized (indicated by a two-dot chain line L3 in FIG. 4). This is advantageous in securing a space for preventing this.

  FIG. 9 shows a cross section (cross section along the vehicle body width direction) of the constricted portion 131 of the deformation control unit 130. In FIG. 9, numbers (1 to 8) are displayed around the center (centroid P <b> 1) of the deformation control unit 130 at every 45 °, from the upper side of the vehicle body to the outer side of the vehicle body to the lower side of the vehicle body to the inner side of the vehicle body. . In this cross section, [1-5 axis] extends in the vertical direction of the vehicle body through the centroid P1. The [2-6 axis] forms an angle of 45 ° with respect to the [1-5 axis], and extends obliquely through the centroid P1 from the outer upper side of the vehicle body toward the inner lower side of the vehicle body. [3-7 axis] extends horizontally through the centroid P1. The [4-8 axis] forms an angle of 45 ° with respect to the [3-7 axis], and extends obliquely through the centroid P1 from the outer lower side of the vehicle body toward the inner upper side of the vehicle body. The [4-8 axis] direction is a direction toward the power plant 38.

  In this specification, the [2-6 axis] related to the section modulus is referred to as a first axis, and [4-8 axis] is referred to as a second axis. The deformation control unit 130 extends from the centroid P1 to each section in the cross section so that the section modulus around the first axis [2-6 axis] is smaller than the section coefficient around the second axis [4-8 axis]. The distance is set. As an example, in the cross section of the deformation control unit 130 shown in FIG. 9, the second reinforcing portion 62a of the upper reinforcement member 62 and the upper surface wall 63a of the upper panel member 63 are respectively connected to the first axis [2- The shape is inclined in the same direction as [6 axes].

  By adopting such a cross-sectional shape, the section modulus around the first axis [2-6 axis] is made smaller than that around the second axis [4-8 axis]. Furthermore, the lower panel member 60 and the lower reinforcement member 61 respectively have ridge portions 60c and 61c located on the second axis [4-8 axis]. The deformation control unit 130 having such a cross-sectional shape is deformed around the first axis [2-6 axis], that is, in the direction of interfering with the power plant 38, as compared with the second axis [4-8 axis]. It becomes easy.

  The first hypotenuse part 102 and the second hypotenuse part 110 of the load transmitting member 70 each have an oblique shape that approaches the subframe main body 52 from the front end 70a to the rear end 70b of the load transmitting member 70. It has become. Moreover, an extension 112 provided at the rear end 70 b of the load transmitting member 70 extends in the direction of the deformation control unit 130 and is connected to the front side of the deformation control unit 130. The extension 112 overlaps the front end of the lower reinforcement member 61 and the front end of the upper reinforcement member 62 at a position on the front side of the constricted portion 131, thereby forming an overlap portion 140 (shown in FIG. 7). . For this reason, the deformation | transformation control part 130 can be made into the starting point of the stable bending mode. That is, when the collision load input from the front end 70 a of the load transmission member 70 is transmitted to the vicinity of the deformation control unit 130 via the load transmission member 70, the deformation control unit 130 may be deformed in a direction that interferes with the power plant 38. Is possible.

Below, an example of an effect | action of the vehicle body front part structure provided with the sub-frame 50 of this embodiment is demonstrated.
FIG. 1 shows a case where a small overlap collision is assumed, and shows a state immediately before a collision partner (impactor) B collides with the vehicle body 11 from the front of the vehicle on the driver's seat side. The small overlap collision referred to in this specification is a collision in which the collision partner B moves from the front of the vehicle 10 toward the cabin 36 along the outer surface of the side member 20 (or 21). This is an offset frontal collision in which the amount of overlap with the collision partner B is relatively small.

  The collision partner B moving from the front of the vehicle 10 first deforms the end of the bumper beam 26 and further moves toward the cabin 36. When the collision partner B moves to a position where it comes into contact with the front end 70a of the load transmission member 70, the load transmission member 70 is pushed rearward (in the direction indicated by the arrow F1 in FIG. 7), and therefore the collision load is applied to the load transmission member 70. Is transmitted in the direction indicated by the arrow F2 toward the vicinity of the deformation control unit 130 of the subframe 50.

  This collision load acts as a force based on the moment in the direction indicated by the arrow F3 in FIG. 7 and pushes the deformation control unit 130 from the outside of the vehicle body, so that the deformation control unit 130 moves outside the vehicle body as shown by the arrow F4 in FIG. The deformation control unit 130 moves in a direction of interfering with the power plant 38 by deforming from the side toward the inner upper side of the vehicle body to the first axis [around the 2-6 axis].

  Therefore, the deformation control unit 130 interferes with a rigid structure such as the power plant 38 as indicated by a two-dot chain line L5, and for example, the first flange FL1 of the deformation control unit 130 is caught by the projection 38c or the like of the transmission 38a. Thereby, the excessive movement of the deformation | transformation control part 130 is suppressed. When there is a convex portion 38d that protrudes to the outside of the vehicle body on the side wall of the power plant 38, excessive movement of the deformation control portion 130 upward is caused by the second flange FL2 abutting from the lower surface side of the convex portion 38d. It may be suppressed.

  As the deformation control unit 130 is deformed in this manner, the power plant 38 is pushed from the outside of the vehicle body by the deformed subframe 50. As a result, the vehicle body front portion 11a moves in the non-collision side (the side away from the collision partner B), that is, in the vehicle body width direction, whereby the deformation amount of the cabin 36 is reduced. The above description is for one subframe 50, but the other subframe 51 may be configured similarly to the one subframe 50.

  In carrying out the present invention, the shape and arrangement of each element constituting the front body structure of the vehicle body such as the side member, suspension cross member, and sub-frame, as well as the sub-frame body, load transmission member, deformation control unit, etc. Needless to say, various modifications can be made to specific embodiments.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Vehicle body, 11a ... Vehicle body front part, 20, 21 ... Side member, 27 ... Suspension cross member, 50, 51 ... Subframe, 52 ... Subframe main body, 60 ... Lower panel member, 61 ... Bottom Side reinforcement member, 62 ... upper reinforcement member, 63 ... upper panel member, 70 ... load transmission member, 70a ... front end, 70b ... rear end, 102, 110 ... hypotenuse part, 130 ... deformation control part, 131 ... constriction part , FL1 ... first flange, FL2 ... second flange.

Claims (6)

A side member extending in the longitudinal direction of the vehicle body;
A vehicle body front structure including a suspension cross member disposed at a position lower than the side member and extending in a width direction of the vehicle body,
A subframe body disposed at a position lower than the side member and extending from the suspension cross member toward the front of the vehicle body;
Provided at the front end of the sub-frame main body, having a front end protruding outward from the vehicle body outer surface of the side member, and having a hypotenuse that approaches the sub-frame main body from the front end toward the rear end A load transmitting member;
By being formed on the rear side of the rear end of the load transmission member at a part in the longitudinal direction of the sub-frame main body and being pushed by the load transmission member when a load from the front of the vehicle body is input to the load transmission member A deformation control unit that deforms in a direction that interferes with a structure in the engine room;
The vehicle body front part structure characterized by comprising.   2. The vehicle body front structure according to claim 1, wherein the deformation control unit has a constricted portion that is recessed toward the inside of the vehicle body on a part of the vehicle body outside in the longitudinal direction of the subframe body.   The deformation control unit relates to a cross section along the vehicle body width direction from the outer lower side of the vehicle body to the inner upper side of the vehicle body, compared with a section coefficient around the first axis from the upper outer side of the vehicle body to the lower inner side of the vehicle body. The vehicle body front part structure according to claim 1 or 2, characterized in that a section modulus around the second axis toward the vehicle is large.   The sub-frame body has a lower panel member and an upper panel member, and the lower panel member has a ridge line portion located on the second axis in a cross section along the vehicle body width direction of the deformation control unit. 4. The upper panel member according to claim 3, wherein the upper panel member has an upper wall on the second shaft that is inclined from the outer upper side of the vehicle body toward the inner lower side of the vehicle body in the cross section. Car body front structure.   The vehicle body front part structure according to any one of claims 1 to 4, wherein the deformation control unit includes a first flange protruding toward the inside of the vehicle body.   The vehicle body front part structure according to claim 5, wherein the deformation control unit has a second flange protruding upward.

Images