JP2016150671A - Front part structure of automobile - Google Patents

Abstract

To provide a front structure of an automobile capable of controlling deformation of a subframe at the time of a collision while suppressing damage to a bolt connecting a subframe to a cross member. A side frame disposed along the vehicle longitudinal direction on both sides in the vehicle width direction of the front portion of the vehicle body, a sub-frame 5L disposed along the vehicle longitudinal direction below the side frame, and the vehicle width direction. And a cross member 4 having a connecting portion 48 having a rear end portion connected to each other in the vehicle width direction via bolts 482 on both sides in the vehicle width direction. 5L is formed on the upper surface of the subframe 5L corresponding to the position of the bulging portion 56 and the bulging portion 56 that bulges below the lower end 484 of the bolt 482 in the front-rear direction of the vehicle body in the longitudinal direction of the connecting portion of the cross member 4. And a recessed portion 55 that reduces the cross-sectional area of the bulging portion 56. [Selection] Figure 4

Description

  The present invention relates to a front structure of an automobile, and relates to a front structure of an automobile that can suppress damage to bolts caused by banging a curb.

  Patent Document 1 includes a front side member disposed on the left and right sides of an engine room on which a power train is mounted, a subframe disposed on a lower side of the engine room that is positioned below the front side member, A front structure of a motor vehicle is disclosed. The sub-frame is formed in a cross-beam shape, the front ends of the side frames on both sides thereof are fastened and fixed to the seats at the lower front end of the front side member, and the rear ends are fastened and fixed to the seats joined to the lower surface of the toe board. . Further, the sub-frame is provided with a bent portion at the center in the front-rear direction of the side frame so as to form a shallow V shape in a side view.

  Patent Document 2 discloses front side members (front side frames) disposed on the left and right sides of an engine room on which a power train is mounted. The front side frame has a frame main body extending substantially horizontally and a front floor frame inclined downward and rearward from the frame main body. The front floor frame has a front frame fastening part provided at the center of the front frame and a rear frame fastening part provided at the rear part, and a sub frame is fastened from below, and the front floor arm is integrated with the floor (underbody). It is joined to.

Japanese Patent No. 3575439 JP 2012-153263 A

By the way, in the front part structure of the automobile disclosed in Patent Documents 1 and 2 described above, when the automobile or the like approaches a curbstone or the like, the sub-frame is viewed from below at the rear frame fastening part provided at the rear part of the front floor frame. If the bolt to be fastened is struck by a curb or the like and the bolt is deformed or damaged, the fixing of the subframe may be loosened or detached, and the deformation mode may not be controlled in the event of a collision. In addition, there is a risk that problems such as the bolts being unable to be removed during maintenance will occur.
In view of the above circumstances, an object of the present invention is to provide a vehicle front structure that can control deformation of a subframe at the time of a collision while suppressing damage to a bolt that connects the subframe to a cross member.

  The present invention includes a side frame disposed along the vehicle longitudinal direction on both sides in the vehicle width direction of the front portion of the vehicle body, a subframe disposed along the vehicle longitudinal direction below the side frame, and the vehicle width direction. A vehicle body front structure including a cross member having a connecting portion to which a rear end portion of the subframe is connected via a bolt on both sides in the vehicle width direction. A bulging part that bulges below the lower end of the bolt in the front-rear direction of the vehicle body in the longitudinal direction of the connecting part of the cross member, and is formed on the upper surface of the subframe corresponding to the position of the bulging part. It has the recessed part which reduces an area, It is characterized by the above-mentioned.

  According to the present invention, the sub-frame has the bulging portion that bulges below the lower end of the bolt at the front in the vehicle longitudinal direction of the connecting portion of the cross member. Since it becomes the 1st grounding point to a curbstone etc., it is controlled that the lower end of the bolt grounded after a bulging part hits a curbstone etc., and damage to a bolt by hard hitting etc. to a curbstone etc. can be controlled. In addition, the subframe is formed on the upper surface of the frame corresponding to the position of the bulging portion, and has a recessed portion that reduces the cross-sectional area of the bulging portion. It is possible to control the deformation by positively bending downward at the position.

In one aspect of the present invention, the bulging portion is formed with a gentle slope in front of the lowest point and a steep slope in the rear in a side view of the vehicle body.
In this way, the bulging portion can be brought closer to the bolt in the longitudinal direction of the vehicle body, and when the automobile approaches the curbstone, it is further suppressed from hitting the lower end of the bolt that comes in contact with the ground after the bulging portion. It is possible to further suppress the damage to the bolt due to the smashing of the bolt.

In one aspect of the present invention, the lower surface of the connecting portion of the cross member is positioned above the lower surface of the rear portion of the connecting portion, and the lowest point of the bulging portion and the lower surface of the rear portion of the connecting portion, Are substantially the same height.
In this way, since the lower end of the bolt is located above the lowermost surface of the cross member, it is further suppressed that the lower end of the bolt hits the curb, and further damage to the bolt due to striking the curb is further suppressed. it can.

In one aspect of the present invention, the recessed portion is provided in an avoidance portion that avoids a front wheel when the vehicle is steered.
In this way, when the automobile collides head-on, the sub-frame is bent at the avoidance portion. Therefore, when the automobile collides head-on, the sub-frame can be bent while avoiding the front wheels.

  As described above, according to the present invention, when the vehicle approaches a curbstone or the like, the bulging part becomes the first grounding point to the curbstone or the like, so that the lower end of the bolt that contacts the ground after the bulging part ( It is possible to suppress the tip) from hitting the curb or the like, and it is possible to suppress damage to the bolt due to banging the curb or the like. In addition, by providing a recessed part corresponding to the position of the bulging part, it is possible to control the deformation by actively bending the subframe downward at the position of the recessed part when the vehicle collides with the front. It becomes.

1 is a perspective view showing a front structure of an automobile according to an embodiment of the present invention. It is a top view which shows the front part structure of the motor vehicle shown in FIG. It is a side view which shows the front part structure of the motor vehicle shown in FIG. It is a side view which shows the outer surface of the sub-frame shown in FIG. It is a side view which shows the inner surface of the sub-frame shown in FIG. FIG. 6 is a cross-sectional view of the subframe shown in FIG. 5 taken along line VI-VI. It is the VII-VII sectional view taken on the line of the sub-frame shown in FIG. FIG. 6 is a sectional view of the subframe shown in FIG. 5 taken along line VIII-VIII. It is the IX-IX sectional view taken on the line of the sub-frame shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments suitable for a front structure of an automobile according to the invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and all the structures demonstrated by this embodiment are not essential as a solution means of this invention.

  FIG. 1 is a perspective view showing a front structure of an automobile 1 according to an embodiment of the present invention. 2 is a plan view showing the front structure of the automobile 1 shown in FIG. 1, and FIG. 3 is a side view showing the front structure of the automobile 1 shown in FIG.

  As shown in FIGS. 1 to 3, the front structure of the automobile 1 according to the embodiment of the present invention is such that a power train 2 is mounted on the front of the automobile 1, and the power train is placed on the front of the automobile 1. 2, a pair of front side members 3 </ b> L and 3 </ b> R (see FIGS. 2 and 3), a cross member 4, and a pair of subframes 5 </ b> L and 5 </ b> R are configured.

  The power train 2 serves as a power source for the automobile 1, and the power train 2 according to this embodiment is configured by connecting an automobile engine and a transmission. Although not shown, the power train 2 is elastically supported by the pair of front side members 3L and 3R via a mount member on the left and right sides in the vehicle width direction, and is elastically supported by the cross member 4 via the mount member. ing.

  As shown in FIGS. 2 and 3, the pair of front side members 3 </ b> L and 3 </ b> R are vehicle body members that constitute the skeleton of the automobile 1, and are provided along the vehicle body longitudinal direction on both sides of the power train 2. Each of the pair of front side members 3L and 3R is formed in a rectangular tube shape having a rectangular cross section, and the rear portion 31 extends obliquely downward.

  The cross member 4 is a vehicle body member provided along the vehicle width direction, is provided along the vehicle width direction behind the power train 2, and is coupled to the rear side of the pair of front side members 3L and 3R. The target cross member 4 in this embodiment is a suspension cross member 40 installed immediately after the power train 2.

  As shown in FIGS. 1 to 3, the suspension cross member 40 is for supporting a suspension (not shown), and an upper frame 41 and a lower frame 42 joined to the upper frame 41 (see FIG. 3). It consists of. The upper frame 41 is formed by press-molding a steel plate having a uniform thickness, is formed in a box shape with an open bottom surface, and is disposed along the vehicle width direction. The lower frame 42 is formed by press-molding a steel plate having a uniform thickness, similar to the upper frame 41, and flanges 411 and 412 provided on the opening front edge and the opening rear edge of the upper frame 41 (see FIG. 2). It is joined to the lower surface of. Thus, the upper frame 41 constitutes the upper surface of the suspension cross member 40, and the lower frame 42 constitutes the lower surface of the suspension cross member 40.

  The suspension cross member 40 includes a pair of front side support portions 43 and 43 extending upward from the upper surface of the suspension cross member 40 at both ends in the vehicle width direction on the front side of the vehicle, and both end portions in the vehicle width direction on the rear side of the vehicle. Are connected to a pair of front side members 3L, 3R at four locations of a pair of rear side support portions 44, 44 provided on the front side. The suspension cross member 40 is supported by a pair of front side members 3L and 3R via front side support portions 43 and 43 and rear side support portions 44 and 44, respectively, at both ends in the vehicle width direction.

  Further, a front arm support portion 45 and a rear arm support portion 46 are provided at both ends in the vehicle width direction of the suspension cross member 40, respectively. The front arm support portion 45 and the rear arm support portion 46 are for supporting a suspension arm (lower arm) 47, and the front arm support portion 45 extends obliquely forward and outward in the vehicle width direction. The support portion 46 extends obliquely rearward in the vehicle width direction.

  A suspension arm 47 is supported on the front arm support portion 45 and the rear arm support portion 46 so as to be rotatable in the vertical direction. A knuckle (not shown) is provided at the tip (outer end) of the suspension arm 47, and the front wheel 6 (see FIG. 2) is supported via the knuckle.

  Further, at the front end portions on both sides in the vehicle width direction of the suspension cross member 40, connecting portions 48 to which the pair of subframes 5L and 5R are connected are provided. The connecting portion 48 is provided with a receiving portion 481 (see FIG. 1) whose front and side surfaces are open. The rear end portion 51 of the subframes 5L and 5R can be inserted into the accommodating portion 481, and the rear end portions 51 of the subframes 5L and 5R accommodated in the accommodating portion 481 are connected to the accommodating portion 481 and the subframes 5L and 5R. Bolts 482 (see FIGS. 1 and 2) penetrating the rear end portion 51 from top to bottom are screwed into nuts (weld nuts) 483 welded to the lower surface of the suspension cross member 40, so that the suspension cross member 40 It is concluded.

  The pair of subframes 5L and 5R has a spacer 57 built in the rear end portion 51. The spacer 57 supports the rear end portion 51 inside the pair of subframes 5L and 5R, and a suspension cross is provided with bolts 482 penetrating the housing portion 481 and the rear end portions 51 of the subframes 5L and 5R from top to bottom. Even if the nuts (weld nuts) 483 welded to the lower surface of the member are tightened, the rear end portions 51 of the subframes 5L and 5R are not crushed.

  The pair of sub-frames 5L and 5R are vehicle body members provided along the vehicle longitudinal direction, similar to the pair of front side members 3L and 3R described above. It extends forward from the front end along the longitudinal direction of the vehicle body.

As shown in FIG. 2, the vehicle body front-rear direction rear region 52 is positioned in the vehicle width direction more than the pair of front side members 3 </ b> L and 3 </ b> R so that the pair of sub-frames 5 </ b> L and 5 </ b> R avoids the steered front wheel 6. The vehicle body front-rear direction front region 53 is provided on the inner side, and is bent substantially at the center of the vehicle body front-rear direction, and extends outward in the vehicle width direction. Thereby, the vehicle body front-rear direction rear area 52 of the pair of sub-frames 5L, 5R constitutes an avoiding portion 54 that avoids the steered front wheel 6.
As shown in FIG. 3, the pair of front side members 3L, 3R and the pair of subframes 5L, 5R are connected at their front ends by a front bracket 7, and the front side members 3L, 3R and the subframe are connected to each other. 5L and 5R are integrated via the front bracket 7 (see FIG. 3).

  4 is a side view showing the outer side surface of the subframe 5L shown in FIG. 3, and FIG. 5 is a side view showing the inner side surface of the subframe 5L shown in FIG. 6 is a sectional view taken along the line VI-VI of the subframe 5R shown in FIG. 5, and FIG. 7 is a sectional view taken along the line VII-VII of the subframe 5R shown in FIG. 8 is a sectional view taken along line VIII-VIII of the subframe 5R shown in FIG. 5, and FIG. 9 is a sectional view taken along line IX-IX of the subframe 5R shown in FIG.

  As shown in FIGS. 6 to 9, the pair of subframes 5L and 5R is composed of a lower subframe 5A and an upper subframe 5B joined to the lower subframe 5A. The lower subframe 5A is formed by press-forming a steel plate having a uniform thickness, is formed in a bowl shape having an open top surface, and is disposed along the vehicle body longitudinal direction. The upper sub-frame 5B is formed by pressing a steel plate having a uniform thickness, like the lower sub-frame 5A. In the state, it is joined (welded) to the lower subframe 5A.

  As shown in FIG. 4, the pair of subframes 5L and 5R includes a front end in the vehicle front-rear direction of the rear end portion 51 through which the bolt 482 passes, specifically, a connecting portion 48 (accommodating portion) of the suspension cross member 40. 481) has a bulging portion 56 that bulges in a mountain shape below the tip (lower end) 484 of the bolt 482 at a position immediately before 481). As a result, when the automobile approaches the curb or the like, the bulging portion 56 of the pair of subframes 5L and 5R becomes the first contact point to the curb or the like, so that the bolt 482 is prevented from being struck by the curb or the like. it can. In addition, it is possible to suppress a stepping stone or the like jumped up by the front wheel 6 during traveling from hitting the bolt 482.

  The bulging portion 56 is formed so that the inclination is gentle in front of the lowest point P and the inclination is steep in the rear as viewed from the side of the vehicle body. That is, the lowest point P of the bulging portion 56 is configured to be a position relatively close to the bolt 482 in the longitudinal direction of the vehicle body. Thereby, the bolt 482 can be more reliably protected. Further, by making the inclination of the front side of the bulging portion 56 gentle, it is possible to mitigate the impact that acts on the sub-frames 5L and 5R when the bulging portion 56 comes into contact with a curbstone or the like.

  Further, the lower surface of the connecting portion 48 of the suspension cross member 40 is positioned above a lower portion of a portion behind the connecting portion 48, for example, a portion to which the suspension arm 47 is connected. The lowest point P of the bulging portion 56 is set to be substantially the same height as the lower surface of the rear portion of the connecting portion 48 of the suspension cross member 40. In other words, the connecting portion 48 is a position recessed upward between the bulging portion 56 and the portion behind the connecting portion 48. As a result, the tip (lower end) 484 of the bolt 482 is positioned above the lower surface of the suspension cross member 40, so that interference of curbs and the like to the bolt 482 can be more reliably suppressed.

  As shown in FIGS. 5 to 9, the pair of sub-frames 5L and 5R are formed in a rectangular tube shape having a smaller cross section than the pair of front side members 3L and 3R described above, and the upper part on the inner side in the vehicle width direction of the avoiding portion 54 A recessed portion 55 is formed in a downwardly recessed manner (see FIG. 5). More specifically, the recessed portion 55 is provided at a position corresponding to the bulging portion 56 and has a smaller cross section than the front region and the rear region as a weak portion whose rigidity is smaller than that of the front region and the rear region. It is formed as follows. Thereby, when the automobile 1 collides head-on and a load of a predetermined value or more is applied, the pair of subframes 5L and 5R are configured to bend downward at the bulging portion 56 with the recessed portion 55 as a boundary. Yes.

  As described above, according to the vehicle body front structure of the automobile 1 according to the present embodiment, the pair of subframes 5L and 5R are below the front end (lower end) 484 of the bolt 482 in the front and rear direction of the bolt 482 in the vehicle body. Therefore, when the automobile 1 approaches a curbstone or the like, the bulge part 56 becomes a first contact point for the curbstone or the like. It is possible to suppress the tip (lower end) from hitting the curb or the like, and it is possible to suppress damage to the bolt 482 due to banging on the curb or the like.

  Moreover, since the recessed part 55 which reduces and forms a cross-sectional area is provided corresponding to the position of the bulging part 56 of a pair of sub-frame 5L, 5R, when the motor vehicle 1 carries out a frontal collision, the recessed part 55 Becomes a weak portion, and the pair of subframes 5L and 5R bend downward at the recessed portion 55. That is, the deformation mode is controlled by the bulging portion 56 and the recessed portion 55 so that the subframes 5L and 5R are positively bent downward at the position of the recessed portion 55. The fall amount of the power train 2 can be stabilized, and the power train 2 can be surely submerged below the passenger compartment.

  Moreover, since the recessed part 55 is provided in the avoidance part 54 which avoids the front wheel 6 when it steers, a pair of sub-frame 5L, 5R bends in the avoidance part 54 when the motor vehicle 1 collides head-on. Thereby, when the automobile 1 has a frontal collision, the pair of subframes 5L and 5R can be bent while avoiding the front wheels 6.

  In addition, since the bulging portion 56 has a gentle slope in front of the lowest point P and a steep slope in the rear as viewed from the side of the vehicle body, the bulging portion 56 can be brought closer to the bolt 482 in the longitudinal direction of the vehicle body. As a result, when the vehicle 1 approaches the curbstone, it is further suppressed from hitting the tip (lower end) of the bolt 482 that comes into contact with the ground after the bulging portion 56, and damage to the bolt 482 due to banging on the curb etc. Can be further suppressed. Moreover, when the bulging portion 56 abuts against the curbstone or the like, it abuts against a surface with a gentle slope, so that the impact acting on the subframes 5L and 5R can be reduced.

  In addition, since the lowest point P of the bulging portion 56 and the lower surface of the rear portion of the connecting portion 48 of the suspension cross member 40 are substantially the same height, the tip (lower end) 484 of the bolt 482 is connected to the suspension cross member 40. It is also located above the lower surface. Thereby, it is further suppressed that the front end portion (lower end portion) of the bolt 482 hits the curbstone, and damage to the bolt 482 due to banging on the curbstone or the like can be further suppressed.

  As described above, according to the present invention, when the automobile approaches a curbstone or the like, the bulging portion serves as the first grounding point to the curbstone or the like. Part) and the nut are prevented from hitting the curbstone and the like, and damage to the bolt and the nut due to banging on the curbstone and the like can be suppressed. Further, since the sub-frame can be controlled to be deformed downward in the event of a collision by the bulging portion and the recessed portion, it is suitable for a vehicle body front structure having a sub-frame.

DESCRIPTION OF SYMBOLS 1 Car 2 Powertrain 3L, 3R Front side member 31 Rear part 4 Cross member 40 Suspension cross member 41 Upper frame 411, 412 Flange 42 Lower frame 43 Front side support part 44 Back side support part 45 Front side arm support part 46 Rear side arm support Part 47 Suspension arm 48 Connection part 481 Housing part 482 Bolt 483 Nut 484 Tip of bolt (lower end)
5L, 5R Subframe 5A Lower subframe 5B Upper subframe 51 Rear end portion 52 Vehicle body front-rear direction rear region 53 Vehicle body front-rear direction front region 54 Avoidance portion 55 Recessed portion 56 Protruding portion 57 Spacer 6 Front wheel 7 Front bracket P Lowermost point

Claims (4)

A side frame disposed along the vehicle longitudinal direction on both sides in the vehicle width direction of the front of the vehicle body;
A sub-frame disposed along the longitudinal direction of the vehicle body below the side frame;
A vehicle body front structure comprising: a cross member disposed along the vehicle width direction, and having cross members each having a connecting portion to which a rear end portion of the subframe is connected via a bolt on both sides in the vehicle width direction;
The subframe is:
A bulging portion that bulges below the lower end of the bolt at the front of the cross member in the longitudinal direction of the vehicle body;
A vehicle body front structure, comprising: a concave portion that is formed on an upper surface of the subframe corresponding to a position of the bulging portion and reduces a cross-sectional area of the bulging portion.   2. The vehicle body front structure according to claim 1, wherein the bulging portion has a gentle slope in front of the lowest point and a steep slope in the rear in a side view of the vehicle body. The lower surface of the connecting portion of the cross member is positioned above the lower surface of the rear portion of the connecting portion,
The vehicle body front part structure according to claim 1 or 2, wherein a lowermost point of the bulging portion and a lower surface of a portion behind the connecting portion have substantially the same height. The vehicle body front structure according to any one of claims 1 to 3, wherein the recessed portion is provided in an avoidance portion that avoids a front wheel when the vehicle is steered.

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