JP5949044B2 - Front subframe structure - Google Patents

Description

  The present invention relates to a front subframe structure that includes an arm support portion that supports a suspension arm and a pair of left and right side members.

  Conventionally, as shown in Patent Document 1 below, one pipe member having a U-shape in plan view, a connecting member (cross member) that connects left and right side portions of the U-shaped pipe member, and the U In a vehicle suspension system provided with a front subframe provided with a transmission means composed of two pipe members arranged in a U-shape with respect to a U-shaped pipe material, the suspension arm is input to the front subframe. The external force is transmitted to the mounting portion provided on the vehicle body side strength member via the transmission means, thereby increasing the mounting rigidity of the suspension arm and improving its torsional rigidity. Yes.

  Further, as shown in Patent Document 2 below, in the assembly structure of the vehicle subframe supported by the vehicle body frame, the subframe includes a front and rear cross pipe extending in the vehicle width direction and a left and right extension extending in the vehicle front and rear direction. A side pipe is welded and joined at a first joint part, and a mount member support pipe is welded and joined to the front and rear cross pipes or left and right side pipes at a second joint part, and the body frame is attached to the mount member support pipe. A cylindrical mount member attached to the vehicle is welded and joined at a third joint portion whose axis extends in the vertical direction, and the mount in at least one of the vehicle width direction, the vehicle front-rear direction, and the vertical direction A tolerance absorbing structure that enables adjustment of the position of the member is employed in the first to third joint portions.

JP 2009-61879 A JP 2001-39333 A

  When the side members of the front subframe consisting of a single pipe material or left and right side pipes having a U-shape in plan view are disposed on the front left and right sides of the vehicle body as disclosed in Patent Documents 1 and 2 above. It is possible to sufficiently ensure the rigidity against the collision load input at the time of the vehicle collision without forming the side member thick. However, when the side member is formed of a pipe-shaped member, the wall surface portion of the side member is liable to surface vibration according to the lateral force or the like input from the suspension arm to the front subframe when the vehicle is running, There is a problem that the cross-sectional shape of the side member is easily plastically deformed. For this reason, it is necessary to secure a certain plate thickness of the pipe-shaped member constituting the side member, and there is room for improvement from the viewpoint of reducing the weight of the front subframe.

  The present invention has been made in view of the above problems, and the side member of the front subframe can be formed to be lightweight and highly rigid, and is input from the suspension arm to the front subframe when the vehicle is traveling. An object of the present invention is to provide a front subframe structure capable of effectively supporting a lateral force or the like with a simple configuration.

The invention according to claim 1 includes a pair of left and right arm support portions that support the suspension arm;
A front subframe structure having a pair of left and right side members extending in the front-rear direction of the vehicle and a cross member extending in the vehicle width direction so as to connect the left and right arm support portions, wherein the side members are A side member front portion having a closed cross-sectional shape positioned on the front side of the arm support portion and a rear side portion of the side member having a closed cross-section shape positioned on the rear side of the arm support portion are divided into the cross section and the arm support portion and the cross. Members are connected to each other through a closed cross-section structure that forms a closed cross section extending in the vehicle width direction, and the rear end of the front side of the side member and the front end of the rear of the side member are joined to the closed cross-section structure, respectively. It has been done.

The invention according to claim 2, said at front subframe structure according to claim 1, when the pair of left and right arm support portion is defined as the front arm support, apart from these front arm support, each side A pipe-shaped cross section having a pair of left and right rear arm support portions connected to the rear portion of the member, wherein the side member front portion has a ridge line extending in the front-rear direction of the vehicle and a flat plate portion disposed between adjacent ridge lines. is formed in a shape, and in which the rear arm support portion is linked side members rear, is formed in a pipe shape cross section having a large curved surface of curvature than the flat portion of the side member front is there.

According to a third aspect of the present invention, in the front subframe structure according to the first or second aspect, the closed cross-section structure includes a mount bracket attached to a vehicle body frame.

According to a fourth aspect of the present invention, in the front sub-frame structure according to any one of the first to third aspects, the closed cross-section structure body is a plate of a pipe material that constitutes a side member front portion and a side member rear portion. It is made of a material thicker than the thickness.

According to a fifth aspect of the present invention, in the front subframe structure according to any one of the first to fourth aspects, the closed cross-section structure is formed of a material thicker than a plate material constituting the cross member. It has been done.

The invention according to claim 6 is the front subframe structure according to any one of claims 1 to 5 , wherein the cross member includes an upper panel and a lower panel that form a closed cross section extending in the vehicle width direction. The cross member and the closed cross-section structure are offset in the front-rear direction of the vehicle so that the rear end of the cross member is located rearward of the rear end of the closed cross-section structure. A pipe-shaped member having left and right inclined portions extending toward the rear side of the vehicle while being inclined from the center portion in the vehicle width direction of the cross member to the left and right outer sides; and both left and right sides of the pipe-shaped member The part is connected to the vehicle body side strength part installed on the left and right of the floor tunnel.

  In the invention according to claim 1, since the side member is constituted by the side member front portion and the side member rear portion having a closed cross-sectional shape, the side member can be formed to be lightweight and highly rigid. When the vehicle travels, for example, a lateral force input to the arm support portion from a suspension arm located on one side of the vehicle body is directly transmitted from the closed cross-section structure to the cross member, and the cross member is Can be transmitted to the other side of the vehicle body, so that the lateral force and the like can be stably suppressed while suppressing the vibration of the wall surface portion of the front side member and the rear side of the side member according to the lateral force and the like. Can be supported.

In addition, since the rear end portion of the side member front portion and the front end portion of the side member rear portion are respectively joined to the closed cross-section structure, the closed cross-section structure functions as a connecting member between the side member front portion and the side member rear portion. be able to. Therefore, by transmitting the collision load input to the front side member at the time of a vehicle collision to the rear side member and the cross member via the closed cross-section structure with a simple and compact configuration, the entire vehicle body There is an advantage that it can be dispersed efficiently and supported efficiently.

In the invention according to claim 2 , since the front side portion of the side member is formed in a pipe-like cross-sectional shape having a ridge line extending in the front-rear direction of the vehicle and a flat plate portion installed between adjacent ridge lines, the front subframe is Car body side strength member provided on the rear side of the side member and on the rear side of the side member while sufficiently supporting the collision load input to the front side member at the time of a vehicle collision without increasing the size of the front side member It is possible to effectively transmit the collision load. In addition, since the rear part of the side member is formed in a pipe-like cross-sectional shape having a curved surface with a larger curvature than the flat part of the front part of the side member, it is input from the rear connecting part of the lower arm to the rear part of the side member when the vehicle is traveling. Therefore, it is possible to effectively prevent the wall surface portion of the rear portion of the side member from vibrating in accordance with the lateral force or the plastic deformation of the cross-sectional shape thereof. Therefore, it is possible to effectively absorb the collision load by improving the proof strength against the collision load input to the front side member at the time of the vehicle collision, and the front sub according to the lateral force input when the vehicle travels. While suppressing the vibration of the frame, it is possible to achieve both the effect of effectively improving the yield strength against the lateral force.

In the invention according to claim 3 , since the closed cross-section structure is constituted by the mount bracket attached to the vehicle body frame, the lateral force input from the lower arm to the arm support portion during the traveling of the vehicle is converted to the second mount bracket. By transmitting to the side frame from the above, there is an advantage that the lateral force and the like can be more efficiently dispersed and effectively supported throughout the vehicle body.

In the invention according to claim 4 , since the closed cross-section structure is formed of a material thicker than the plate thickness of the pipe material constituting the side member front part and the side member rear part, the main part of the front subframe is constituted. By effectively reducing the weight of the side member, while dispersing the lateral force, etc., input from the suspension arm to the closed cross-section structure body through the cross member and the side member while the vehicle is running, There is an advantage that it can be supported effectively.

In the invention according to claim 5 , since the closed cross-section structure is made of a material thicker than the plate material constituting the cross member, the cross member constituting the main part of the front subframe is effectively reduced in weight. On the other hand, there is an advantage that a collision load inputted from the front side member front part to the closed cross-section structure can be stably supported by transmitting the collision load to the rear side member rear part at the time of a vehicle collision.

In the invention according to claim 6 , the cross member is constituted by an upper panel and a lower panel forming a closed cross section extending in the vehicle width direction, and a rear end portion of the cross member is a rear end portion of the closed cross section structure. The cross member and the closed cross-section structure are arranged so as to be positioned on the rear side of the vehicle, offset in the vehicle front-rear direction, and tilted from the center in the vehicle width direction of the cross member to the left and right outer sides. Since the pipe-like member having left and right inclined parts extending toward the rear side of the vehicle is provided, and both the left and right side parts of the pipe-like member are connected to the vehicle body side strength parts installed on the left and right of the floor tunnel, the cross member Is constructed so that the side end of the cross section straddles the closed cross-section structure and the front portion of the rear side of the side member, so that the connecting portion between the closed cross-section structure and the rear side of the side member is reinforced by the cross member. Can be, it is possible to effectively improve the rigidity of the front subframe. Further, the lateral force or the like input from the suspension arm to the front portion of the cross member is applied to the vehicle body side strength installed on the floor panel from the cross member through the center portion in the vehicle width direction of the pipe-like member and the left and right inclined portions. There exists an advantage that it can support effectively by transmitting to a member.

It is side surface sectional drawing which shows 1st Embodiment of the front sub-frame structure which concerns on this invention. It is a perspective view which shows the state which looked at the said front sub-frame structure from diagonally upper front. It is a perspective view which shows the state which looked at the said front sub-frame structure from diagonally lower front. It is a top view which shows the specific structure of the said front sub-frame structure. It is a bottom view which shows the specific structure of the said front sub-frame structure. It is front sectional drawing which shows the specific structure of a side member front part. It is front sectional drawing which shows the specific structure of a side member rear part. It is front sectional drawing which shows the structure of the junction part of a front sub-frame and a vehicle body. It is a top view which shows the specific structure of a lower arm. It is front sectional drawing which shows the specific structure of a 2nd mount bracket. It is a plane sectional view showing the concrete composition of the 2nd mount bracket. It is side surface sectional drawing which shows the modification of the said front sub-frame structure.

  1-5 has shown the vehicle provided with the front sub-frame structure which concerns on embodiment of this invention. A power plant 1 including a driving engine or a driving motor is disposed at the front of the vehicle, and a vehicle compartment and an installation space (engine room) for the power plant 1 are partitioned behind the power plant 1. A dash panel 2 is provided. A pair of left and right side frames 3 are installed so as to extend from the lower end of the dash panel 2 to the front side of the vehicle, and a front subframe 5 that supports a lower arm 4 for front suspension and the like below the side frame 3. Is installed.

  The side frame 3 has a front part 3a extending substantially horizontally along the front-rear direction of the vehicle in a side view, and a rear side of the dash panel 2 from the rear end part toward the lower end part of the dash panel 2 while being inclined rearward. And a rear frame 3b, which will be described later, is connected to the rear end of the rear portion 3b. In addition, a crash can 6 made of a metal cylindrical body or the like is projected from the front end of the side frame 3 toward the front side of the vehicle, and a bumper extending in the vehicle width direction is provided at the front end. A side end portion of the reinforcement 49 is attached.

  The front sub-frame 5 is disposed below the side frame 3 and extends in the front-rear direction of the vehicle, and a pair of left and right side members 7 and the lower side of the side frame 3 on the rear side of the space where the power plant 1 is disposed. And a first cross member 8 made of a pipe-like member described later. The floor panel 9 constituting the bottom of the passenger compartment is provided with a floor tunnel 35 bulging upward in the center in the vehicle width direction so as to extend in the longitudinal direction of the vehicle.

  The front upper wall of the floor tunnel 35 is provided with an inclined portion 35a (see FIG. 1) inclined rearward and lower, more specifically on the front side of the rear end of the inclined portion 35a. A second cross member (rear cross member) 10 that couples the left and right end portions of the first cross member 8 extends in the vehicle width direction. Further, a third cross member (center cross member) 11 and a fourth cross member (front cross member) 12 are formed in a substantially linear shape along the vehicle width direction at the intermediate portion and the front portion of the left and right side members 7, respectively. It is extended to.

  The side member 7 is positioned on the front side of the vehicle with respect to a front arm support portion 18 to be described later, and includes a side member front portion 13 that is installed in an upwardly inclined state in a side view (see FIG. 1), and a front side It is divided into a rear side portion 14 of the side member that is located on the rear side of the vehicle with respect to the arm support portion 18 and is installed substantially horizontally in a side view. Further, a crash can 15 made of a metal cylindrical body or the like protruding toward the front of the vehicle is attached to the front end portion of the side member front portion 13.

  As shown in FIG. 6, the side member front portion 13 has a substantially square shape having four ridge lines 13a extending in the longitudinal direction of the vehicle and four flat plate portions 13b disposed between adjacent ridge lines 13a. It is formed in a pipe-like cross-sectional shape. Further, as shown in FIG. 4, the side member front portion 13 is installed so as to extend from the front end of the second mount bracket 17 to the front side of the vehicle while inclining outward in the vehicle width direction in a plan view. ing. A first mount bracket 16 is installed on the upper surface of the front end portion of the side member front portion 13 so that the upper end portion thereof is fastened to the lower surface of the front portion of the side frame 3 with a fastening bolt. The side end portion of the fourth cross member 12 is integrally joined to the portion by welding or the like.

  As shown in FIG. 7, the side member rear portion 14 is configured in a cross-sectional shape (a round pipe shape in this embodiment) having a curved surface having a larger curvature than the flat plate portion 13 b of the side member front portion 13. . Then, as shown in FIG. 4 in plan view, the side member rear portion 14 is installed so as to extend from the rear end of the second mount bracket 17 to the rear side of the vehicle while inclining inward in the vehicle width direction. Yes. In addition, on the lower outer surface of the second mount bracket 17 installed between the side member front portion 13 and the side member rear portion 14, a below-described front side connecting portion 43 provided at the base end portion of the lower arm 4 is provided. A front arm support portion 18 to be supported is provided (see FIGS. 4 and 10).

  On the side member rear portion 14, three round pipe members 19, which are attachment parts for vehicle auxiliary equipment including a stabilizer or a steering rack (not shown), are located near the rear portion of the second mount bracket 17 and on the rear side thereof. (See FIG. 2 etc.) As shown in FIG. 5, the rear end portion of the side member rear portion 14 is inward in the vehicle width direction with respect to the joint portion 20 with respect to the floor frame 37 provided at the left and right end portions of the first cross member 8. By welding to the front side portion of the portion facing the fixing portion 34 with respect to the tunnel lower frame 38 (described later) provided on the left and right side portions of the first second cross member 10. They are connected together.

  As shown in FIG. 1, the center cross member comprising the third cross member 11 comprises an upper panel 22 and a lower panel 23 made of a steel plate or the like that form a substantially rectangular closed cross section extending in the vehicle width direction. Yes. Then, the left and right side end portions of the upper panel 22 and the lower panel 23 are welded to the inner side surface in the vehicle width direction of the second mount bracket 17, so that the left and right second mount brackets 17 are connected to the third cross member 11. (See FIG. 4).

  The rear end portion of the third cross member 11 is disposed rearward of the rear end portion of the second mount bracket 17, and the rear outer surface of the third cross member 11 is in front of the side member rear portion 14. It is joined to the inner side surface. Further, an opening 25 serving as an introduction portion of the rear mount 24 of the power plant 1 made of a vehicle engine or the like and a power plant support for supporting the rear mount 24 are provided in the vehicle width direction central portion of the third cross member 11. And a support bracket 27 for supporting the vehicle width direction central portion 28 of the first cross member 8 made of a pipe-like member.

  The first cross member 8 is made of a pipe-like member formed by bending a circular steel pipe or the like, and has a vehicle width direction central portion 28 installed so as to extend in the vehicle width direction, and the vehicle width in plan view. It has a pair of left and right inclined portions 29 that are installed so as to extend from the left and right end portions of the direction center portion 28 toward the rear side of the vehicle in a C shape. Then, the first cross member 8 and the third cross member 11 are connected to each other in the vehicle width direction by, for example, welding the center portion 28 in the vehicle width direction of the first cross member 8 to the support bracket 27 of the third cross member 11. They are connected together at the center.

  The rear end portion of the inclined portion 29 is bent so as to extend outward in the vehicle width direction, and the end portion thereof is crushed into a flat shape, thereby forming a joint portion 20 to be joined to the floor frame 37 described below. Has been. Further, the side member 7 and the first cross member 8 are integrally connected by welding the rear end portion of the side member 7 to the front surface of the rear portion of the inclined portion 29. Further, the left and right end portions of the second cross member 10 are welded to the rear rear side of the inclined portion 29, so that the left and right end portions of the first cross member 8 are interposed via the second cross member 10. Are connected to each other.

  The left and right ends of the first cross member 8 are vertically connected so as to straddle the joint 20 to the floor frame 37 provided at the rear end of the inclined portion 29 and the rear end of the side member rear portion 14. A rear arm support portion 31 made of a pair of plate members is installed (see FIG. 2). As will be described later, a rear connection portion 44 provided at the base end portion of the suspension arm including the lower arm 4 is supported by the rear arm support portion 31.

  The second cross member 10 is composed of an upper panel 32 and a lower panel 33 made of a steel plate or the like that form a substantially rectangular closed section extending in the vehicle width direction, and side portions of the upper panel 32 and the lower panel 33 are arranged. Welded and phase joined. The left and right ends of the second cross member 10 are provided with fixing portions 34 that are wider than the center in the vehicle width direction. The fixing portions 34 are provided at the front end of the tunnel lower frame 38. It is fixed to the vehicle body by bolting.

  As shown in FIG. 1, the vertical dimension of the second cross member 10 is set smaller than the vertical dimension of the first cross member 8, and the longitudinal dimension of the second cross member 10 is the same as that of the third cross member 11. It is set to the same extent as the front and rear dimensions. As a result, the area of the closed cross section formed by the second cross member 10 in the vehicle width direction central portion is larger than the area of the closed cross section in the vehicle width direction central portion 28 of the first cross member 8 made of the pipe-shaped member. It is set to a small value.

  A floor tunnel 35 that bulges toward the vehicle interior side (upper side) and extends in the front-rear direction of the vehicle is provided at the center in the vehicle width direction of the floor panel 9 that constitutes the vehicle compartment bottom. Further, on the lower surface of the floor panel 9, as shown in FIG. 5, a floor frame 37 extending continuously from the rear end of the side frame 3 to the rear side of the vehicle is placed at a predetermined distance from the floor tunnel 35. A pair of left and right tunnel lower frames 38 are installed along the lower side of the floor tunnel 35 so as to extend in the front-rear direction of the vehicle.

  Then, the joint portion 20 provided at the rear end portion of the first cross member 8 is fastened to the front end portion of the floor frame 37 via a fastening bolt, and at the side end portion of the second cross member 10. The provided fixing portion 34 is fastened to the lower surface of the front end portion of the tunnel lower frame 38 via a fastening bolt, so that the rear portions of the side members 7 are fixed to the vehicle body side strength member at the left and right positions respectively. Yes. As shown in FIG. 8, the floor frame 37 and the tunnel lower frame 38, and the joint portion 20 of the first cross member 8 and the fixing portion 34 of the second cross member 10 that connect the floor frame 37 and the tunnel lower frame 38 are U-shaped in a front view. A continuous structure is formed, and an opening 40 corresponding to the vertical dimension of the fixed portion 34 and the joint portion 20 is formed between the structure and the floor panel 9.

  In addition, side sills 36 are installed on the left and right sides of the floor panel 9 so as to extend in the front-rear direction of the vehicle, and a torque box 39 that connects the front part of the side sill 36 and the front part of the floor frame 37 is connected. Is installed (see FIG. 5). The torque box 39 has a front plate extending in the vehicle width direction along the lower portion of the dash panel 2 disposed in the front portion of the passenger compartment, and a bottom plate extending from the lower end portion to the rear side of the vehicle. The front plate and a ridge line provided at the lower end thereof extend from the position adjacent to the portion where the joint 20 is disposed toward the outer side in the vehicle width direction.

  As shown in FIGS. 5 and 9, the lower arm 4 supported by the front subframe 5 has a tip end portion 42 connected to a wheel support member (axle housing) (not shown) via a ball joint or the like. It consists of a so-called A-type arm in which a pair of front and rear front connection parts 43 and a rear connection part 44 are provided on the inner side (base end) in the vehicle width direction. The front connecting part 43 and the rear connecting part 44 of the lower arm 4 are a front arm supporting part 18 provided on the first mounting bracket 17 of the front subframe 5 and a rear arm supporting part provided on the side member rear part 14. 31 is supported so as to be swingable and elastically displaceable.

  In other words, the front connecting portion 43 of the lower arm 4 is provided with a support shaft 45 extending in the front-rear direction of the vehicle and a rubber bush 46 that holds the support shaft 45. And the fastening part provided in the front-and-rear both ends of the said support shaft 45 is fastened by the front side arm support part 18 provided in the base end part of the said 2nd mount bracket 17 via a fastening bolt, The said lower arm 4 is connected to the support shaft 45 as a fulcrum, and is supported so as to be elastically displaceable according to the elasticity of the rubber bush 46.

  As shown in FIGS. 10 and 11, the second mount bracket 17 installed between the side member front portion 13 and the side member rear portion 14 is obliquely above the side end portion of the third cross member 11 and has a vehicle width. An upper panel 75 projecting outward in the direction, a lower panel 76 disposed below the upper panel 75, and a cylindrical shape fastened to the lower surface of the side frame 3 via fastening bolts 53. And an attachment portion 54.

  The upper panel 75 of the second mount bracket 17 includes an upper wall plate 77 extending obliquely upward from the upper surface of the side end portion of the third cross member 11, and a pair of lower walls extending from the front and rear side end portions of the upper wall plate 77. It has a side wall plate 78 and an inner wall plate 79 extending downward from the inner end in the vehicle width direction of the upper wall plate 77, and the upper wall plate 77 and the tip of the side wall plate 78 (outer end in the vehicle width direction). Is fixed by welding the cylindrical mounting portion 54. Further, at the front end portion of the side wall plate 78, when a predetermined collision load is input to the front subframe 5 at the time of a vehicle collision, the side frame is deformed by deforming the support portion of the cylindrical mounting portion 54. A pair of upper and lower cutouts 57 and 58 are formed as a weakened portion for facilitating the second mount bracket 17 from detaching from 3.

  The lower panel 76 of the second mounting bracket 17 is installed below the upper wall plate 77 of the upper panel 75 at a predetermined interval. The lower end of the cylindrical mounting portion 54 is disposed on the upper surface of the distal end portion of the lower panel 76. The parts are to be welded. And the closed cross-section structure which forms the closed cross-section 80 extended in a vehicle width direction by welding the lower end part of the side wall board 78 of the upper panel 75 and the inner wall board 79 to the outer periphery part of the said lower panel 76 is said 2nd. The mount bracket 17 is used.

  The upper panel 75 and the lower panel 76 constituting the second mount bracket 17 are formed to be thicker than the plate thickness of the pipe material constituting the side member front portion 13 and the side member rear portion 14, and the third panel The upper member 22 and the lower panel 23 of the cross member 11 are formed of a steel plate material thicker than the steel plate material. The rear end portion of the side member front portion 13 is welded to the front surface of the proximal end portion of the second mount bracket 17, and the front end portion of the side member rear portion 14 is welded to the proximal end of the second mount bracket 17. The side member front portion 13 and the side member rear portion 14 are connected to each other via the second mount bracket 17 by being welded to the rear surface of the portion.

  A side end portion of the third cross member 11 that forms a substantially rectangular closed section extending in the vehicle width direction by the upper panel 22 and the lower panel 23 is an inner wall of the upper panel 75 constituting the second mount bracket 17. While being joined to the plate 79, a pair of front and rear nut members constituting the front arm support portion 18 are fixed to the base end portion (lower portion) of the lower panel 76. The front arm support 18 provided at the base end of the lower panel 76 and the third cross member 11 joined to the inner wall plate 79 of the upper panel 75 are interposed via the second mount bracket 17. They are linked together.

  As shown in FIG. 9, a support shaft 62 extending in the vertical direction and a rubber bush 63 for holding the support shaft 62 are provided in the rear connection portion 44 of the lower arm 4. The upper and lower end portions of the support shaft 62 are fixed to the rear arm support portion 31 made of a pair of upper and lower plate members laid across the side member rear portion 14 and the joint portion 20 of the first cross member 8. Thus, the rear connecting portion 44 of the lower arm 4 is supported so as to be rotatable with the support shaft 62 as a fulcrum, and is supported so as to be elastically displaceable according to the elasticity of the rubber bush 63.

  The front sub-frame 5 is carried into the vehicle assembly line in a state where the front suspension device having the lower arm 4 is sub-assembled, and is introduced from the lower side of the side frame 3 to the front of the vehicle body. Then, the upper ends of the first and second mount brackets 16 and 17 provided on the side member 7 of the front subframe 5 are bolted to the lower surface of the side frame 3, so that the front end of the side member 7 and Center portions in the front-rear direction are attached to the side frames 3, respectively.

  Further, the joint portion 20 provided at the rear end portion of the first cross member 8 is bolted to the front end portion of the floor frame 37 installed on the lower surface of the floor panel 9, and the second cross member 10 is The fixing portions 34 provided at both left and right ends are bolted to the front end portion of the tunnel lower frame 38 installed along the lower end portion of the floor tunnel 35, so that both the left and right portions of the front subframe 5 are provided. The rear end portions of the side members 7 are fixed to the vehicle body-side strength member including the floor frame 37 and the tunnel lower frame 38 at two positions on the left and right, respectively.

  A power plant 1 including a vehicle engine or the like is installed between the left and right side frames 3, and the rear mount 24 of the power plant 1 is powered from an opening 25 formed on the front surface of the third cross member 11. The rear part of the power plant 1 is supported by the front sub-frame 5 by being introduced into the plant support part 26 and bolted.

  In the above configuration, when the vehicle travels, for example, as indicated by an arrow A in FIGS. 4 and 5, the front side provided on the second mount bracket 17 from the front side connecting portion 43 of the lower arm 4 located on one side (right side) of the vehicle body. When a lateral force is input to the arm support 18, the lateral force is transmitted to the other (left side) side member 7 via the third cross member 11 as indicated by an arrow B, and the arrow As shown in C, a floor frame 37 and a tunnel lower frame that are transmitted from the support bracket 27 of the third cross member 8 to the vehicle width direction central portion 28 and the left inclined portion 29 of the first cross member 8 and located on the rear side thereof. It is transmitted to and supported by 38 etc.

  Further, when the vehicle is running, for example, as shown by an arrow D in FIGS. 4 and 5, a rear arm support provided on the side member 7 from the rear connecting portion 44 of the lower arm 4 located on one side (right side) of the vehicle body. As indicated by an arrow E, the lateral force input to the portion 31 is transmitted from the right inclined portion 29 of the first cross member 8 to the vehicle width direction central portion 28 and the third cross member 11. Then, the lateral force transmitted to the third cross member 11 is transmitted to the other (left side) side member 7 as indicated by an arrow B and supports the third cross member 8 as indicated by an arrow C. It is transmitted from the bracket 27 to the vehicle width direction central portion 28 and the left inclined portion 29 of the first cross member 8, and is transmitted to and supported by the floor frame 37, the tunnel lower frame 38, and the like located on the rear side.

  On the other hand, when a collision load is input to the side member front portion 13 located on the left side of the vehicle body, for example, as indicated by an arrow F in FIGS. , H, a floor frame 37 and a tunnel lower on the left side of the vehicle body via a joint portion 20 disposed on the rear portion of the first cross member 8 located on the left side of the vehicle body and a fixing portion 34 of the second cross member 10. Each is transmitted to the frame 38 and dispersed and supported by these. Further, as indicated by arrows I and J, the collision load is applied to the floor frame 37 and the tunnel lower via the joint portion 20 of the first cross member 8 and the fixing portion 34 of the second cross member 10 located on the right side of the vehicle body. It is transmitted to the frame 38 and is also dispersed and supported by these.

  Therefore, when a predetermined collision load that cannot be absorbed according to the deformation of the crash can 15 is input to the side member 7 of the front subframe 5, the side member rear portion 14 may fall inward or the side member 7 While effectively preventing the rear end portion of the rear member from detaching from the vehicle body side strength member, a collision load is applied to the side member front portion 13 in a concentrated manner to deform it into a bellows shape, for example. Thus, it is possible to efficiently absorb the collision load input at the time of the collision of the vehicle.

  Further, when a large collision load acts in a direction in which the power plant 1 supported by the front subframe 5 is moved backward in the event of a vehicle collision, the axle shaft of the power plant 1 abuts on the second mount bracket 17. For example, a load that pushes the cylindrical mounting portion 54 of the second mount bracket 17 fastened to the lower surface of the side frame 3 backward acts. Further, the supporting portion of the cylindrical mounting portion 54 is provided with a fragile portion that facilitates the separation of the second mount bracket 17 from the side frame 3, that is, the notches 57 and 58 of the side wall plate 78. Therefore, when a predetermined collision load is applied during a vehicle collision, the support portion of the cylindrical mounting portion 54 can be greatly deformed, and the second mount bracket 17 can be detached from the side frame 3.

  Further, as shown in FIG. 1, a collision load K that pushes the side member front part 13 diagonally downward at the time of a vehicle collision is applied to the side member front part 13 that is installed in an upwardly inclined state in a side view. Therefore, the front sub-frame 5 may be swung downward with the two fixed portions including the joint portion 20 and the fixed portion 34 disposed at the rear portion of the first cross member 8 as fulcrums. The power plant 1 allowed and held by the front subframe 5 is guided downward and descends.

  As described above, the front arm support portion 18 that supports the suspension arm composed of the lower arm 4, the pair of left and right side members 7 extending in the front-rear direction of the vehicle, and the left and right front arm support portions 18 are coupled to each other in the vehicle width direction. In a front sub-frame structure having a center cross member comprising a third cross member 11 extending to the side cross section, the side member 7 is closed to the front side of the front arm support portion 18 and has a closed cross-section side member front portion. 13 and a side member rear portion 14 having a closed cross-sectional shape located rearward of the front arm support portion 18, and the front arm support portion 18 and the third cross member 11 extend in the vehicle width direction. When configured so as to be connected to each other via the second mounting bracket (closed section structure) 17 constituting the closed section 80, In compact configuration, the lateral force or the like inputted from the lower arm 4 during traveling of the vehicle in front subframe 5 is advantageous in that it is possible to stably support.

  That is, since the side member 7 is constituted by the side member front portion 13 and the side member rear portion 14 formed of a pipe-like body having a closed cross-sectional shape, the side member 7 can be formed to be lightweight and highly rigid. When the vehicle travels, for example, a lateral force or the like input from the lower arm 4 located on one side of the vehicle body to the front arm support portion 18 is directly transmitted from the second mount bracket 17 to the third cross member 11. At the same time, since it can be transmitted to the other side of the vehicle body via the third cross member 11, the wall surface portions of the side member front portion 13 and the side member rear portion 14 are prevented from vibrating according to the lateral force or the like. However, the lateral force and the like can be stably supported.

  In the above embodiment, since the rear end portion of the side member front portion 13 and the front end portion of the side member rear portion 14 are respectively joined to the closed cross-section structure including the second mount bracket 17, the second mount The bracket 17 can function as a connecting member between the side member front portion 13 and the side member rear portion 14. Accordingly, with a simple and compact configuration, the collision load input to the side member front portion 13 at the time of a vehicle collision is transmitted to the side member rear portion 14 and the third cross member 11 via the second mount bracket 17. Thus, there is an advantage that it can be dispersed efficiently throughout the vehicle body and supported efficiently.

  Furthermore, as shown in the said embodiment, the side member front part 13 is a square pipe provided with the several ridgeline 13a extended in the front-back direction of a vehicle, and the flat plate part 13b arrange | positioned between the adjacent ridgelines 13a. In the case of a cross-sectional shape such as a shape, the side member front portion 13 constituting the front subframe 5 is not enlarged, and the collision load input to the side member front portion 13 at the time of a vehicle collision is sufficiently obtained. While being supported, the collision load can be effectively transmitted to the side member rear portion 14 and the vehicle body side strength member provided behind the side member rear portion 14. When the collision load input to the side member front portion 13 becomes a certain value or more, the collision load can be effectively absorbed by plastically deforming the side member front portion 13 in a bellows shape or the like. Therefore, there is an advantage that the collision load can be effectively prevented from reaching the side member rear portion 14 and the vehicle interior.

  In the above embodiment, the side member rear portion 14 has a round pipe-like cross-sectional shape with a curved surface having a larger curvature than the flat plate portion 13b of the side member front portion 13, so that the lower arm 4 is connected to the rear side when the vehicle is traveling. The wall surface portion of the side member rear portion 14 undergoes surface vibration or the sectional shape thereof is plastically deformed in accordance with the lateral force or the like input from the portion 44 to the side member rear portion 14 via the second mount bracket 17. It can be effectively prevented. Therefore, as described above, the side member front portion 13 has a square pipe-like cross-sectional shape, and the side member rear portion 14 has a round pipe-like cross-sectional shape. While suppressing the vibration of the front subframe 5 in accordance with the lateral force input during the traveling of the vehicle and the effect of improving the proof stress against the input collision load and effectively absorbing the collision load, It is possible to achieve both the effect of effectively improving the resistance to lateral force.

  The side member front portion 13 has a pipe-like cross-sectional shape other than a substantially square shape, for example, a square pipe-like cross-sectional shape provided with a plurality of ridgelines made of rectangles or hexagons and flat plate portions disposed between the ridgelines. In addition, the side member rear portion 14 has a pipe-like cross-sectional shape other than the round pipe shape, for example, an elliptical shape or a heart-shaped cross-sectional shape having a curved surface having a larger curvature than the flat plate portion 13b of the side member front portion 13. It is good. Even in such a configuration, it is possible to effectively absorb the collision load by improving the resistance against the collision load input to the side member front portion 13 at the time of the collision of the vehicle, and the traveling of the vehicle. There is an advantage that at the same time, it is possible to effectively improve the proof strength against the lateral force while effectively preventing the front sub-frame 5 from vibrating according to the lateral force or the like that is sometimes input. is there.

  Moreover, in the said embodiment, the closed cross-section structure which mutually connects the front side arm support part 18 which supports the front side connection part 43 of the lower arm 4, and the 3rd cross member 11 installed between the left and right side members 7, Since the second mount bracket 17 is attached to the center portion in the front-rear direction of the vehicle body frame including the side frames 3, the lateral force input from the lower arm 4 to the front arm support portion 18 during traveling of the vehicle is used as the second mount. By transmitting from the bracket 17 to the vehicle body frame including the side frames 3, there is an advantage that the lateral force and the like can be more efficiently dispersed and effectively supported throughout the vehicle body.

  As shown in the above embodiment, when the plate thickness of the steel plate material constituting the second mount bracket 17 is formed thicker than the plate thickness of the pipe material constituting the side member front portion 13 and the side member rear portion 14 The lateral force and the like input from the lower arm 4 to the second mount bracket 17 when the vehicle is running while effectively reducing the weight of the side member 7 that constitutes the main part of the front sub-frame 5. There is an advantage that it can be effectively supported by being dispersed throughout the vehicle body via the third cross member 11 and the side member 7.

  Further, when the plate thickness of the steel plate material constituting the second mount bracket 17 is formed thicker than the upper panel 22 and the lower panel 23 constituting the third cross member 11, the front subframe The center cross member comprising the third cross member 11 constituting the main portion 5 is effectively reduced in weight, and the collision load input from the side member front portion 13 to the second mount bracket 17 at the time of vehicle collision is reduced. There is an advantage that it can be stably supported by transmitting to the side member rear portion 14 and the like.

  Further, as shown in the above embodiment, the third cross member 11 is constituted by an upper panel 22 and a lower panel 23 that form a closed cross section extending in the vehicle width direction, and a rear end portion of the third cross member 11 is formed. When the third cross member 11 and the second mount bracket 17 are offset in the vehicle front-rear direction so as to be positioned rearward of the rear end portion of the second mount bracket 17, the first 3 The side end of the cross member 11 is constructed so as to straddle the second mount bracket 17 and the front portion of the side member rear portion 14, thereby connecting the second mount bracket 17 and the side member rear portion 14 to the above-mentioned second portion. Since the three cross members 11 can reinforce, the rigidity of the front sub-frame 5 can be effectively improved.

  In addition, a first cross comprising a pipe-like member having a pair of left and right inclined portions 29 extending toward the rear side of the vehicle while inclining from the vehicle width direction center portion 28 of the third cross member 11 to the left and right outer sides thereof. When the member 8 is provided and both the left and right side portions of the first cross member 8 are connected to the vehicle body side strength portion including the floor frames 37 installed on the left and right sides of the floor tunnel 35, the front side of the lower arm 4 is provided. A lateral force or the like input from the connecting portion 43 to the front portion of the third cross member 11 is converted into a vehicle width direction central portion 28 and left and right inclined portions of the third cross member 11 to the first cross member (pipe-like member) 8. There is an advantage that it can be effectively supported by transmitting to the vehicle body side strength member such as the floor frame 37 installed on the floor panel 9 via 29.

  In addition, at the time of a vehicle collision, the collision load input to the side member front portion 13 is arranged behind the third cross member 11 in the vehicle width direction center portion and the left and right inclined portions 29 of the first cross member 8. Can be transmitted to the floor frame 37 and the like, and can be dispersed and supported by them, so that the first cross member 8 effectively suppresses the side member rear portion 14 from falling in response to the collision load. On the other hand, there is an advantage that the collision load input at the time of the collision of the vehicle can be efficiently absorbed by concentrating the collision load on the side member front portion 13 and compressing and deforming the same in, for example, a bellows shape. .

  That is, in the above embodiment, the front arm support portion 18 that supports the front connection portion 43 of the suspension arm that is the lower arm 4 and the rear arm support portion 31 that supports the rear connection portion 44 of the lower arm 4 are supported on the front subframe 5. And a third cross extending between the left and right side members 7 and extending in the vehicle width direction so as to connect the installation portion of the front arm support portion 18. In a front sub-frame structure having a member (center cross member) 11, a vehicle width direction center portion 28 supported by a support bracket 27 provided on the third cross member 11, and both left and right end portions thereof outward. A first cross member 8 made of a pipe-like member having a pair of inclined portions 29 extending toward the rear side of the vehicle while inclining is installed, Since the joint portions 20 provided at the left and right end portions of the scmember 8 are joined to the vehicle body side strength member composed of the floor frame 37, the vehicle width direction central portion 28 of the first cross member 8 is positioned below the front portion of the floor tunnel 35. Without causing the lateral force input to the front sub-frame 5 from the front connecting portion 43 and the rear connecting portion 44 of the lower arm 4 during traveling of the vehicle via the third cross member 8 and the first cross member 8. By transmitting to the vehicle body side strength member comprising the floor frame 37 and the tunnel lower frame 38 installed on the floor panel 9, it can be stably supported.

  Therefore, the main part of the connecting member made of a large-diameter U-shaped pipe material or the rear cross pipe constituting the vehicle subframe is installed below the front part of the floor tunnel 35 as in the conventional example. Thus, the layout of the engine exhaust pipe 1a and the propeller shaft installed in the floor tunnel 35 is obstructed, and the large-diameter U-shaped pipe member is disposed below the floor panel 9. As a result, the ground height of the floor panel 9 is increased, and the lower arm 4 is moved from the lower arm 4 to the front subframe 5 while the vehicle is running without causing adverse effects such as deterioration of the boarding / alighting performance, the safety and the aerodynamic characteristics of the vehicle. There is an advantage that the input lateral force and the like can be stably supported.

  Further, the rear end portion of the side member 7 installed so as to extend in the front-rear direction of the vehicle along the side portion of the power plant placement space as described above is joined to the vehicle body side strength member such as the floor frame 37. Since the first cross member 8 is connected to the left and right front surfaces of the first cross member 8 located on the inner side in the vehicle width direction with respect to 20, the collision load input to the side member 7 at the time of a vehicle collision is applied to both the left and right sides of the first cross member 8. It can be received by the department. Therefore, it is possible to effectively prevent the rear end portion of the side member 7 from bending and deforming, and to apply the collision load input to the side member 7 to the joint portion 20 disposed at the rear portion of the first cross member 8. Can be effectively supported by being transmitted to the floor frame 37 or the like. When a predetermined collision load is applied to the side member 7 of the front subframe 5, the collision load is concentratedly applied to the side member front portion 13 to deform the side member front portion 13 into a bellows shape. For example, there is an advantage that the collision load can be absorbed efficiently.

  Further, as shown by arrows I and J in FIGS. 3 and 4, the collision load is transmitted obliquely rearward of the vehicle from the support bracket 27 of the third cross member 11 through the inclined portion 29 of the first cross member 8. Then, it is dispersed from the joint portion 20 disposed at the rear end portion of the first cross member 8 and the fixing portion 34 of the second cross member 10 to the floor frame 37 and the tunnel lower frame 38 located on the right side of the vehicle body. Each can be supported. For this reason, the side member rear portion 14 is tilted inward according to the collision load by the first cross member 8 and the collision load is applied to the side member front portion 13 in a concentrated manner. By compressing and deforming, for example, in a bellows shape or the like, it is possible to efficiently absorb a collision load input at the time of a vehicle collision.

  Further, in the event of a vehicle collision, the axle shaft of the power plant 1 is applied to the second mount bracket 17 of the side member 7 in accordance with a collision load that acts in the direction of retreating the power plant 1 supported by the front subframe 5. The second mount bracket 17 is released from the fastened state, for example, by being brought into contact with it, and as shown in FIG. The front subframe 5 is allowed to swing downward with the two fixed portions provided at the rear of the first cross member 8 as fulcrums according to the collision load K acting in the direction. Therefore, when the vehicle collides, the power plant 1 held by the front subframe 5 is guided downward so that the power plant 1 Can be suppressed from interfering with the Sshupaneru 2, it has the advantage of effectively preventing such a power plant 1 from entering the passenger compartment.

  As shown in the above embodiment, when the side member front portion 13 is installed so as to extend from the vicinity of the front end of the side member rear portion 14 to the outer side in the vehicle width direction in plan view so as to extend to the front side of the vehicle, A sufficient length of the side member front portion 13 can be secured and the whole can function as a collision load absorbing portion. Further, since the front arm support portion 18 is provided on the vehicle width direction outer side surface of the second mount bracket 17 disposed on the rear side of the side member front portion 13 and on the inner side in the vehicle width direction, the front arm support portion 18 is provided. Can be positioned on the inner side in the vehicle width direction, thereby sufficiently securing the arm length (dimension in the vehicle width direction) of the suspension arm composed of the lower arm 4 and effectively improving the suspension geometry. There is an advantage that can be.

  Further, in the above embodiment, the side member rear portion 14 is provided with the three round pipe members 19 that serve as attachment portions for vehicle auxiliary equipment such as a stabilizer or a steering rack (not shown). The side member rear portion 14 can be effectively reinforced with a simple configuration by using the mounting portion of the vehicle auxiliary machine or the like without providing a separate reinforcing member for reinforcing the 14. Therefore, the rigidity of the front subframe 5 with respect to the collision load of the vehicle input to the side member rear portion 14 and the first cross member 8 and the lateral force at the time of traveling, etc. is easily and sufficiently secured, and the side according to the collision load. It is possible to effectively prevent the rear part 14 of the member from falling inward and to suppress the deformation of the front sub-frame 5 due to a lateral force or the like input from the lower arm 4 when the vehicle is running, thereby improving the running stability of the vehicle. There is an advantage that it can be improved.

  Further, as shown in the above embodiment, a rear arm support portion 31 for supporting the rear connection portion 44 of the suspension arm made of the lower arm 4 is provided at the side end portion of the first cross member 8 made of the pipe-like member. In the case of laying over the joined portion 20 and the rear end portion of the side member rear portion 14, a reinforcing member for reinforcing the rear end portion of the side member rear portion 14 is not provided separately. The rear portion of the side member rear portion 14 can be effectively reinforced with a simple configuration using the rear arm support portion 31. Therefore, the vehicle can easily and sufficiently secure rigidity against the collision load of the vehicle input to the side member rear portion 14 and the first cross member 8 and the lateral force at the time of traveling. It is possible to effectively prevent the vehicle from falling down and to effectively improve the running stability of the vehicle by suppressing the front subframe 5 from being deformed by a lateral force or the like input from the lower arm 4 when the vehicle is running. There are advantages.

  In the above-described embodiment, the second cross member (rear cross member) 10 is provided immediately below the front end of the floor tunnel 35 and extending in the vehicle width direction so as to connect the left and right ends of the first cross member 8. Further, the area of the closed cross section in the vehicle width direction central portion of the second cross member 10 is set to a value smaller than the area of the closed cross section in the vehicle width direction central portion 28 of the first cross member 8 made of the pipe-shaped member. As in the case where a large rear cross member or the like is provided below the front portion of the floor tunnel 35, the layout of each member including the engine exhaust pipe 1a or the propeller shaft installed in the floor tunnel 35 is improved. The vehicle collision load and the lateral force at the time of traveling input from the first cross member 8 to the tunnel lower frame 38 while suppressing obstruction, etc. There is an advantage that the rigidity can be effectively improved for. Therefore, the floor tunnel 35 is expanded and contracted according to the lateral force or the like input from the first cross member 8 of the front sub-frame 5 to the tunnel lower frame 38 when the vehicle is running, with a simple and lightweight configuration. There is an advantage that can be prevented.

  In particular, as shown in the above-described embodiment, in a vehicle in which a rearwardly inclined portion 35a is formed on the front upper wall of the floor tunnel 35, the second cross member 10 is placed in front of the rear end of the inclined portion 35a. When the vertical dimension of the second cross member 10 in the vehicle width direction central portion is set to a value smaller than that of the first cross member 8 made of the pipe-shaped member, the upper surface portion of the floor tunnel 35 is disposed. The floor tunnel 35 is secured by the second cross member 10 while a sufficient space is provided between the (inclined portion 35a) and the second cross member 10 for installing the exhaust pipe 1a or the propeller shaft of the engine. It is possible to effectively reinforce the lower part of the front part and effectively prevent the expansion / contraction deformation.

  A second cross member 10 for connecting the left and right end portions of the first cross member 8 is disposed on the front side of the front end of the downwardly inclined portion 35a formed on the front upper wall of the floor tunnel 35. Even when the vertical dimension of the second cross member 10 in the vehicle width direction central portion is set to a value larger than that of the first cross member 8, the vehicle in the vehicle width direction central portion of the second cross member 10 is also used. By setting the front-rear dimension to a value smaller than that of the first cross member 8 and positioning the second cross member 10 on the front side of the vehicle as much as possible, the upper surface portion (inclined portion 35a) of the floor tunnel 35 and the first cross member A sufficient space for installing the exhaust pipe 1a of the engine or the propeller shaft can be secured between the two cross members 10.

  On the other hand, as shown in FIG. 12, the front upper wall 35 b of the floor tunnel 35 is formed substantially horizontally, and the left and right end portions of the first cross member 8 are located behind the front end of the floor tunnel 35. In the vehicle in which the second cross member 10A is connected, the vertical dimension of the second cross member 10A is the vertical dimension of the first cross member 8 regardless of the longitudinal dimension at the center in the vehicle width direction. By setting the second cross member 10A to a lower side of the vehicle as much as possible by setting it to a smaller value, the engine is placed between the front upper wall 35b of the floor tunnel 35 and the second cross member 10A. A sufficient space can be secured for installing the exhaust pipe 1a or the propeller shaft.

  Further, in the above-described embodiment, the fixing portions 34 provided on the left and right side portions of the second cross member 10 are arranged at the lower side portion of the floor tunnel 35 at a position spaced apart from the vehicle body-side strength member composed of the floor frame 37. It is fixed to another vehicle body side strength member consisting of a tunnel lower frame 38 arranged along the road. Then, as shown in FIG. 8, the vehicle body side strength member including the floor frame 37 and the tunnel lower frame 38, the joint portion 20 of the first cross member 8, and the fixing portion 34 of the second cross member 10, Since the U-shaped continuous structure was formed, the rigidity of the vehicle body at the support portions of the first cross member 8 and the second cross member 10 was sufficiently ensured and input to the first cross member 8. Lateral force and the like during traveling can be transmitted from the joint portion 20 and the fixed portion 34 to the floor frame 37 and the tunnel lower frame 38 to be effectively supported. Moreover, a harness or the like routed between the floor frame 37 and the tunnel lower frame 38 is connected to the engine room from the joint 20 and the opening 40 formed between the fixing part 34 and the floor panel 9. There is an advantage that it can be easily derived.

3 Side frame (body frame)
4 Lower arm (suspension arm)
5 Front sub-frame 7 Side member 8 First cross member (pipe-shaped member)
11 Third cross member 13 Side member front part 13a Ridge line 13b Flat plate part 14 Side member rear part 17 Second mount bracket (closed cross-section structure)
18 Front arm support portion 22 Upper panel 23 Lower panel 35 Floor tunnel 37 Floor frame (vehicle body side strength member)

Claims (6)

A pair of left and right arm support portions that support the suspension arm, a pair of left and right side members that extend in the front-rear direction of the vehicle, and a cross member that extends in the vehicle width direction so as to connect the left and right arm support portions. Front subframe structure,
The side member is divided into a closed cross-section side member front portion located on the front side of the arm support portion and a closed cross-section side member rear portion located on the rear side of the arm support portion, and The arm support portion and the cross member are coupled to each other via a closed cross-section structure that forms a closed cross section extending in the vehicle width direction, and the rear end portion of the side member front portion and the front end portion of the side member rear portion are the closed cross section. A front subframe structure characterized by being joined to each structure. When defining the pair of left and right arm support portions as a front arm support portion, apart from these front arm support portions, it has a pair of left and right rear arm support portions connected to the rear portion of each side member,
The side where the side member front part is formed in a pipe-like cross-sectional shape having a ridge line extending in the front-rear direction of the vehicle and a flat plate part installed between adjacent ridge lines, and the rear arm support part is connected The front sub-frame structure according to claim 1, wherein the rear portion of the member is formed in a pipe-like cross-sectional shape having a curved surface having a larger curvature than the flat plate portion of the front portion of the side member. The front sub-frame structure according to claim 1 or 2 , wherein the closed cross-section structure includes a mount bracket attached to a vehicle body frame. The said closed cross-section structure was formed with the raw material thicker than the plate | board thickness of the pipe material which comprises a side member front part and a side member rear part, The any one of Claims 1-3 characterized by the above-mentioned. Front subframe structure. The front subframe structure according to any one of claims 1 to 4 , wherein the closed cross-section structure is formed of a material thicker than a plate member constituting the cross member. The cross member includes an upper panel and a lower panel that form a closed cross section extending in the vehicle width direction, and a rear end portion of the cross member is positioned rearward of a rear end portion of the closed cross section structure. The cross member and the closed cross-section structure are disposed offset in the front-rear direction of the vehicle, and extend toward the rear side of the vehicle while inclining from the center in the vehicle width direction of the cross member to the left and right outer sides. with a pipe-shaped member having an inclined portion of the left and right it is provided, according to claim 1 to 5 in which the left and right side portions of the pipe-shaped member is characterized in that it is connected to the vehicle body side strength portion disposed on the left and right of the floor tunnel The front subframe structure according to any one of the above.

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