JP6899411B2 - Body front structure - Google Patents

Description

The present invention relates to a vehicle body front structure.

There is known a vehicle body front structure that absorbs the energy of the impact load by plastically deforming the front side frame when the impact load is input (see, for example, Patent Documents 1 and 2).

The vehicle body front structure described in Patent Documents 1 and 2 is provided with a fragile portion such as a concave portion on the inner surface of the front side frame in the vehicle width direction. In this vehicle body front structure, when an impact load is input to the front side frame, bending deformation of the front side frame starts centering on the fragile part, and the energy of the impact load is absorbed while the front side frame is plastically deformed. To.

International Publication No. 2015/12227 Japanese Unexamined Patent Publication No. 2016-607

The vehicle body front structure described in Patent Documents 1 and 2 is provided with a fragile portion such as a concave portion in a part of the front side frame to promote the start of plastic deformation of the front side frame when an impact load is input. There is. Therefore, when an impact load exceeding a specified value is input to the front side frame, the front side frame starts to be deformed, but once the deformation is started, the deformation resistance of the front side frame becomes small. As a countermeasure, it is conceivable to add a separate plate material to control the deformation of the front side frame at an appropriate position on the front side frame, but in this case, the number of parts increases and the product cost rises. Is a concern.

Therefore, the present invention is intended to provide a vehicle body front structure capable of efficiently absorbing the energy of an impact load without adding many members.

The vehicle body front structure according to the present invention adopts the following configuration in order to solve the above problems.
That is, the vehicle body front structure according to the present invention includes a front side frame (for example, the front side frame 2 of the embodiment) that extends substantially along the vehicle body front-rear direction and has a polygonal cross-sectional shape that intersects the vehicle body front-rear direction. The front side frame has a vehicle width from an inner side wall facing inward in the vehicle width direction (for example, the inner side wall 20 of the embodiment) and an upper ridge line portion of the upper end of the inner side wall (for example, the upper ridge line portion 21 of the embodiment). An upward sloping wall extending upward in the direction (for example, an upward sloping wall 22 of the embodiment) and a lower ridge extending downwardly outward in the vehicle width direction from a lower ridge line portion (for example, a lower ridge line portion 25 of the embodiment) at the lower end of the inner wall surface. It has an inclined wall (for example, the lower inclined wall 26 of the embodiment), and the inner side wall has a bending promoting portion (for example, a bending promoting portion (for example) that extends in the vertical direction of the vehicle body and facilitates bending deformation of the inner side wall in the vehicle width direction. For example, the bending promoting portion 14) of the embodiment is provided, and the front side is located at the front-rear position in the vehicle body front-rear direction with the bending promoting portion sandwiched between at least one of the upper inclined wall and the lower inclined wall. It is characterized in that a pair of recessed portions (for example, the recessed portion 31 of the embodiment) that are recessed in the inward direction of the cross section of the frame are provided.

In the above configuration, when an impact load is input to the front side frame, the front side frame tends to bend and deform outward in the vehicle width direction centering on the bending promoting portion of the inner side wall, and at this time, the upper ridge line portion and the lower ridge line portion The load is concentrated in the vicinity of the bending promotion part. As a result, the vicinity of the bending promoting portion of the upper ridge line portion and the lower ridge line portion starts bending deformation together with the inner side wall, and accordingly, the wall surface of the upper inclined wall and the lower inclined wall on the side where the recessed portion is provided. However, it is deformed so as to be depressed in the cross section centering on each recessed portion before and after the bending promoting portion. As a result, a wide area near the bending promoting portion of the front side frame is deformed in multiple directions, and the energy of the impact load is absorbed during the deformation.

The vehicle body front structure further comprises a mount bracket (eg, the mount bracket 44 of the embodiment) that is fixed to the front side frame and to which a subframe is attached, the mount bracket of the front side frame with respect to the vehicle body front-rear direction. It may be fixed at a position sandwiched between the pair of the recessed portions.

In this case, since the fixed portion of the mount bracket is positioned at a position shifted in the front-rear direction of the vehicle body with respect to each recessed portion, the fixed portion of the mount bracket deforms each recessed portion when an impact load is input. It does not interfere.

On the side of the upward inclined wall and the downward inclined wall where the pair of the recessed portions is provided, a bulging portion (for example, implemented) that bulges inward in the vehicle width direction between the pair of the recessed portions. The bulging portion 32) of the form may be provided.

In this case, since the bulging portion that bulges inward in the vehicle width direction is located between the pair of dents, the pair of dents bulges when an impact load is input to the front side frame. It is easy to be deformed so that it is individually depressed in the cross section of the front side frame. Therefore, when this configuration is adopted, the energy of the impact load can be absorbed more efficiently by the front side frame.

At the end of the inclined wall provided with the pair of the recessed portions and the bulged portions on the opposite side of the inner side wall, a substantially horizontal wall extending outward in the vehicle width direction (for example, under the embodiment). A wall 28) is continuously provided, and a first bending line on the front side (for example, the first bending line 33 of the embodiment) and a second bending line on the rear side (for example, the second bending line of the embodiment) are connected to the substantially horizontal wall. A section area (for example, a section area 35 of the embodiment) is provided by the bend line 34), and the first bend line and the second bend line are extension lines thereof in a front view of the substantially horizontal wall. May extend in the vehicle width direction so as to pass through each of the recesses.

In this case, since the partition area is provided below or above the recessed portion of the substantially horizontal wall, and the first bending line and the second bending line are arranged before and after the partition area, a pair at the time of inputting the impact load. When the recessed portion of the recess is about to be deformed, the partition region stably supports the edge of each recessed portion. Therefore, the deformation of each recessed portion in the depressed direction at the time of inputting the impact load is stable.

The vehicle body front structure further comprises a mount bracket (eg, the mount bracket 44 of the embodiment) fixed to the front side frame and to which a subframe is attached, the mount bracket having a pair of recesses and bulges. It may be fixed to the inclined wall provided with and, and may be fixed to the section area of the substantially horizontal wall.

In this case, since the mount bracket is not fixed to the inclined wall having the recessed portion, the deformation of the recessed portion at the time of inputting the impact load is not hindered by the fixed portion of the mount bracket.

At least one bent portion (for example, the bent portion 30 of the embodiment) is provided at a position in the vehicle body front-rear direction sandwiched between the pair of the recessed portions of the upper ridge line portion and the lower ridge line portion. You may.

In this case, the bending deformation in the horizontal direction of the upper ridge line portion and the lower ridge line portion at the time of inputting the impact load is promoted by the bending portion.

The inner side wall may have a concave groove (for example, the concave groove 36 of the embodiment) extending linearly in a substantially horizontal direction from the front end to the rear end in the front-rear direction of the vehicle body.

In this case, the continuous concave groove on the inner side wall can increase the bending deformation resistance of the front side frame when an impact load is input. This makes it possible to efficiently absorb the energy of the impact load by the plastic deformation of the front side frame.

In the front side frame, a positioning hole (for example, the positioning hole 38 of the embodiment) used during press working may be formed in a region other than the bending promoting portion at the bottom of the concave groove.

In this case, when the front side frame is press-molded, the plate material of the material can be accurately positioned on the press machine by using the positioning holes.

It is desirable that the front side frame is formed of a high-strength steel plate of at least 980 MPa or more.

In this case, the lightweight high-strength steel plate can prevent the front side frame from being broken and deformed.

The front side frame incorporates a partition wall member (for example, partition wall members 39A, 39B of the embodiment) that reinforces the cross section of the front side frame from the inside, and the partition wall member is the inner surface of the front side frame. It may be connected to the region where the recess does not exist.

In this case, since the partition wall member is not coupled to the region where the recessed portion is present on the inner surface of the front side frame, the partition wall member does not hinder the deformation of the recessed portion in the depressed direction when an impact load is input.

The vehicle body front structure further includes a cross member for mounting components erected on the front side frame (for example, the cross member 12 of the embodiment), and the cross member is more than a bending promoting portion of the front side frame. An end joint portion fixed to the front side or the rear side (for example, the end joint portion 13 of the embodiment) is provided, and the end joint portion is separated from the bending promotion portion on the front side frame. A first joint portion (for example, the insertion hole 47 of the embodiment) located on the side and a second joint portion (for example, the notch groove 48 of the embodiment) located on the side close to the bending promotion portion. The second coupling portion may be configured so that the coupling with the front side frame can be released according to the deformation of the front side frame centered on the bending promoting portion.

In this case, when the front side frame tries to bend and deform outward in the vehicle width direction with the bending promoting portion as the center when the impact load is input, the second coupling portion remains fixed to the front side frame. Is released from the front side frame. As a result, the cross member does not hinder the bending deformation centered on the bending promoting portion of the front side frame.

The front side frame has a hat cross-section member that opens in the vehicle width direction (for example, the frame body 2A of the embodiment) and a closing plate member that is coupled to the side of the opening of the hat cross-section member and closes the opening (for example). , And the outer plate 2B) of the embodiment, and the plate thickness of the hat cross-section member may be set to be thicker than the plate thickness of the closing plate member.

In this case, when an impact load is input to the front side frame, the inside of the ridgeline of the hat cross-section member is deformed in a substantially square shape (the ridgeline portion is crushed in the cross section) to absorb energy. At this time, since the hat cross-section member is set to be thicker than the closed plate member, it is possible to absorb a larger amount of energy.

The hat cross-sectional member and the closing plate member are formed with concave grooves (for example, the concave grooves 36 and 37 of the embodiment) extending linearly in a substantially horizontal direction from the front end to the rear end in the front-rear direction of the vehicle body. Is also good.

In this case, the bending deformation resistance of the front side frame at the time of inputting the impact load can be increased by the continuous concave grooves of the hat cross-section member and the closing plate member. This makes it possible to efficiently absorb the energy of the impact load by the plastic deformation of the front side frame.

The front side frame is provided with a front bending promoting portion (for example, the front bending promoting portion 15 of the embodiment) that facilitates bending deformation inward in the vehicle width direction on the front side of the vehicle body with respect to the bending promoting portion. A rear bending promoting portion (for example, the rear bending promoting portion 16 of the embodiment) may be provided on the rear side of the vehicle body with respect to the bending promoting portion to facilitate bending deformation inward in the vehicle width direction.

In this case, when the impact load is input, the front bending promoting portion, the bending promoting portion, and the rear bending promoting portion are the starting points of the bending deformation, and the front side frame is alternately bent and deformed in the substantially horizontal direction. Therefore, when this configuration is adopted, the energy of the impact load can be absorbed more efficiently by the front side frame.

The vehicle body rear structure includes a lower member (for example, the lower member 5 of the embodiment) arranged outside the front side frame in the vehicle width direction, and a connecting member (for example) for connecting the front end portion of the front side frame and the front end portion of the lower member. , The outrigger 6) of the embodiment, the bumper beam arranged in front of the vehicle (for example, the bumper beam 10 of the embodiment), and the energy absorbing member (for example, the embodiment) interposed between the bumper beam and the connecting member. The first extension 8 and the second extension 9) of the form may be further provided.

In this case, when an impact load is input to the bumper beam, the impact load is transmitted to the front side frame and the lower member while deforming the bumper beam and the energy absorbing member. When an impact load is input to the front side frame and the lower member in this way, the front side frame is bent and deformed alternately in a substantially horizontal direction, and the lower member is also bent and deformed. During this time, the energy of the impact load is absorbed by the deformation of each member.

According to the present invention, when an impact load is input, the wall surface of the upper inclined wall and the lower inclined wall on the side where the recessed portion is provided is formed together with the bending deformation at the bending promoting portion of the inner side wall of the front side frame. , It is deformed so as to be depressed in the cross section centering on each recessed portion before and after the bending promoting portion. Therefore, when the present invention is adopted, when an impact load is input, a wide range in the vicinity of the bending promoting portion of the front side frame can be deformed in multiple directions, so that the impact load can be applied without adding many members. Energy can be absorbed efficiently.

The perspective view which shows the skeleton part of the front part left side of the vehicle of embodiment. The perspective view which shows the skeleton part of the front part left side of the vehicle of embodiment. Top view of a part of the front side frame of the embodiment. A perspective view of the front side frame of the embodiment as viewed from the inside in the vehicle width direction. A side view of the front side frame of the embodiment as viewed from the outside in the vehicle width direction with the partition wall member removed. A side view of the front side frame of the embodiment as viewed from the outside in the vehicle width direction. A partial cross-sectional perspective view of a part of the front side frame of the embodiment as a cross section along the line VII-VII of FIG. A partial cross-sectional perspective view of a part of the front side frame of the embodiment as a cross section along the line VIII-VIII of FIG. A partial cross-sectional perspective view of a part of the front side frame of the embodiment as a cross section along the IX-IX line of FIG. A perspective view of the front side frame of the embodiment as viewed from the inside in the vehicle width direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, front / rear, up / down, and left / right shall mean front / rear, up / down, and left / right of the vehicle unless otherwise specified. Further, it is assumed that the arrow FR in the figure points to the front of the vehicle, the arrow UP points to the upper side of the vehicle, and the arrow LH points to the left side of the vehicle.

FIG. 1 is a perspective view showing a skeleton portion of the left front portion of the vehicle 1 of the embodiment.
The vehicle 1 of the present embodiment is provided with a pair of left and right front side frames 2 extending substantially along the front-rear direction of the vehicle body at the front portion of the vehicle body. A lower member 5 is provided on the outer side of the front side frame 2 in the vehicle width direction so as to extend from the vicinity of the suspension support portion (damper housing 3 and damper base 4) so as to curve downward toward the front side.
The front side frame 2 extends from the vehicle interior region to the front of the vehicle body, and the lower member 5 extends from the vehicle interior to the front of the vehicle body from the vehicle width direction outer region.

An outrigger 6 (connecting member) that connects the front side frame 2 and the lower member 5 is attached to the front end portion. A base plate 7 is attached to the front surface of the outrigger 6 so as to face the front of the vehicle. A first extension 8 which is an energy absorbing member is attached to an extension upper position of the front side frame 2 on the front surface of the base plate 7. Further, a second extension 9 which is an energy absorbing member is attached to a position on the front surface of the base plate 7 which overlaps with the front end portion of the lower member 5 in the front-rear direction. Each front end portion of the first extension 8 and the second extension 9 is coupled to the side rear surface of the bumper beam 10 extending substantially along the vehicle width direction. A resin bumper face (not shown) is attached to the front surface of the bumper beam 10.

FIG. 2 is a perspective view showing a front side frame 2 on the left front side of the vehicle 1 of the embodiment and members erected on the left and right front side frames 2.
As shown in FIG. 2, a cross member 12 for mounting the high-voltage component 11 is attached to the front side frame 2. At the end of the cross member 12, an end connecting portion 13 for fastening and fixing the cross member 12 to the upper surface of the front side frame 2 is provided.
FIG. 3 is an enlarged plan view showing the joint portion between the end joint portion 13 and the front side frame 2. The details of the end joint portion 13 will be described in detail later.

A bending promoting portion 14 is provided at a substantially central portion of the front side frame 2 in the front-rear direction to facilitate bending deformation of the front side frame 2 outward in the vehicle width direction when an impact load is input from the front-rear direction of the vehicle body. ing. The front side frame 2 is further provided with a front bending promoting portion 15 and a rear bending promoting portion 16. The front bending promoting portion 15 is arranged on the front side of the vehicle body with respect to the bending promoting portion 14, and facilitates bending deformation of the front side frame 2 inward in the vehicle width direction when an impact load is input from the vehicle body front-rear direction. The rear bending promoting portion 16 is arranged on the rear side of the vehicle body with respect to the bending promoting portion 14, and facilitates bending deformation of the front side frame 2 inward in the vehicle width direction when an impact load is input from the vehicle body front-rear direction.

As shown in FIG. 2, the front side frame 2 is joined to the frame body 2A (hat cross-sectional member) that opens in a substantially U shape outward in the vehicle width direction, and opens and closes the opening of the frame body 2A. It includes an outer plate 2B (closed plate member). The frame body 2A has joint flanges 2Ab bent upward and downward at the upper and lower ends of a substantially U-shaped cross-sectional portion 2Aa, respectively. The outer plate 2B has upper and lower side edges joined to the joining flange 2Ab so as to close the opening of the substantially U-shaped cross-sectional portion 2Aa.
In the case of the present embodiment, the plate thickness of the frame main body 2A (hat cross-section member) is set to be thicker than the plate thickness of the outer plate 2B (closed plate member). Further, the frame body 2A and the outer plate 2B are formed of a high-strength steel plate of at least 980 MPa or more.

FIG. 4 is a perspective view of the frame body 2A of the front side frame 2 on the left side as viewed from the inside in the vehicle width direction, and FIG. 5 is a perspective view of the front side frame 2 on the left side from the outside in the vehicle width direction with some parts removed. It is a side view as seen. Further, FIG. 6 is a side view of the left front side frame 2 when the outer plate 2B is removed and viewed from the outside in the vehicle width direction. FIGS. 7, 8, and 9 are cross sections of each part of the front side frame 2. It is a figure.
The substantially U-shaped cross section 2Aa of the frame body 2A has an inner side wall 20 that hangs inward in the vehicle width direction and an upward inclined wall 22 that extends outward and upward in the vehicle width direction from the upper ridge line portion 21 at the upper end of the inner wall surface 20. And an upper wall 24 extending substantially horizontally outward in the vehicle width direction from the second upper ridge line portion 23 at the upper end of the upper inclined wall 22. The outer end of the upper wall 24 in the vehicle width direction is connected to the upper joint flange 2Ab. The substantially U-shaped cross-sectional portion 2Aa further includes a lower inclined wall 26 extending outward and downward in the vehicle width direction from the lower ridge line portion 25 at the lower end of the inner side wall 20, and a vehicle from the second lower ridge line portion 27 at the lower end of the lower inclined wall 26. It has a lower wall 28 extending substantially horizontally outward in the width direction. In this embodiment, the lower wall 28 constitutes a substantially horizontal wall. The outer end of the lower wall 28 in the vehicle width direction is connected to the lower joint flange 2Ab.

As shown in FIG. 4, the above-mentioned bending promoting portion 14 is formed along the vertical direction at a substantially central position of the inner side wall 20 in the front-rear direction. The bending promoting portion 14 is composed of, for example, a bending groove recessed in a notch shape in the outward direction in the vehicle width direction, a curved portion, a thin portion, and the like. In the case of the present embodiment, bending lines 29 are provided before and after the bending promoting portion 14. Further, the upper ridge line portion 21 and the lower ridge line portion 25 adjacent to the inner side wall 20 are provided with bending portions 30 so as to be continuous with the respective bending lines 29 before and after the inner side wall 20.

As shown in FIG. 5, a pair of recesses in the lower inclined wall 26 that are recessed in the cross-sectional inner direction of the front side frame 2 at the front-rear position in the vehicle body front-rear direction sandwiching the bending promotion portion 14 of the inner side wall 20 between them. The portion 31 is formed. In the case of the present embodiment, the recessed portion 31 is formed in a spherical shape or other three-dimensional curved shape. The pair of recessed portions 31 are formed on the front side of the bending line 29 on the front side of the inner side wall 20 and on the rear side of the bending line 29 on the rear side.
Further, in the downward inclined wall 26, a bulging portion 32 that bulges inward in the vehicle width direction is formed at an intermediate position in the front-rear direction of the pair of recessing portions 31.

Further, in the lower portion of the lower wall 28, which is the lower portion of the bulging portion 32, a rectangular partition region 35 whose front and rear are partitioned by the first bending line 33 and the second bending line 34 is provided. The first bending line 33 on the front side and the second bending line 34 on the rear side are such that the extension lines of the bending lines 33 and 34 pass through approximately the center of each of the front and rear recesses 31 in the front view of the lower wall 28. It extends in the width direction of the vehicle.

Further, recessed grooves 36 and 37 extending substantially linearly from the front end to the rear end in the front-rear direction of the vehicle body are formed in the frame body 2A (hat cross-section member) and the outer plate 2B (closing plate member) of the front side frame 2, respectively. ing. The concave groove 36 of the frame main body 2A is formed so as to be recessed in the vehicle width direction at substantially the center of the inner side wall 20 of the frame main body 2A in the height direction. The concave groove 36 is formed with a widening portion 36a having a substantially circular shape in front view in a part on the front side of the bending promoting portion 14 of the frame main body 2A. A circular positioning hole 38 used during press working is formed on the circular bottom wall of the widened portion 36a. The positioning hole 38 is used, for example, when positioning the frame body 2A on the press machine. Further, the concave groove 37 of the outer plate 2B is formed so as to be recessed inward in the vehicle width direction at a position substantially the same height as the concave groove 36 of the frame main body 2A.

As shown in FIGS. 6 to 9, a pair of partition wall members 39A and 39B for reinforcing the closed cross section of the front side frame 2 from the inside are attached to the inside of the substantially U-shaped cross section 2Aa of the frame body 2A. ing. The pair of partition wall members 39A and 39B are attached to two positions in the inside of the frame body 2A near the bending promoting portion 14 that sandwiches the bending promoting portion 14 in the front-rear direction of the vehicle body.

The partition wall members 39A and 39B are attached to a pair of partition wall function walls 40a and 40b arranged apart from each other in the front-rear direction of the vehicle body, a connecting wall 40c connecting the partition wall function walls 40a and 40b, and the partition wall function walls 40a and 40b. It has a plurality of extending joint flanges 40d. The partition wall function walls 40a and 40b are formed in a substantially rectangular shape, and are arranged so as to cross the closed cross section of the front side frame 2. The connecting wall 40c connects the pair of partition wall function walls 40a and 40b to each other at the outer position in the vehicle width direction. The joining flange 40d is welded and fixed to the inner surfaces of the upper wall 24, the lower wall 28, and the inner side wall 20 of the frame body 2A. Further, the connecting wall 40c is appropriately fixed to the outer plate 2B by bolting or the like in a state where the opening of the substantially U-shaped cross-sectional portion 2Aa of the frame body 2A is closed by the outer plate 2B.

Here, the partition members 39A and 39B are welded and fixed to the inner surface of the frame body 2A at the joint flange 40d portion as described above, but the lower inclined wall 26 of the frame body 2A in which a pair of recesses 31 are formed is formed. Not fixed to. That is, the partition wall members 39A and 39B are connected to the inner surface of the front side frame 2 in the region where the recessed portion 31 does not exist.

A pair of collars 41 are integrally attached to the upper portion of the connecting wall 40c in the partition wall member 39A installed on the front side of the bending promoting portion 14 of the front side frame 2. A thread groove is formed in the inner peripheral portion of each collar 41 to which the shaft portion of the fastening bolt 42 (see FIGS. 2 and 3) is screwed. The bolt 42 is a bolt for fastening the end joint portion 13 of the cross member 12 shown in FIGS. 2 and 3 to the upper surface of the front side frame 2. As shown in FIG. 1, the shaft portion of the bolt 42 is inserted into the insertion hole 43 formed in the upper wall 24 of the front side frame 2 and fastened to the corresponding collar 41 arranged on the lower surface of the upper wall 24. To.

FIG. 10 is a perspective view of the front side frame 2 from the inside in the vehicle width direction in the vicinity of the substantially central portion in the vehicle body front-rear direction.
As shown in FIGS. 5 to 10, a mount bracket 44 for attaching a subframe (not shown) is attached to a position on the lower rear side of the bending promoting portion 14 near the substantially central portion of the front side frame 2. For example, a drive system device, a suspension device, or the like (not shown) is supported on the subframe.

The mount bracket 44 is provided on a flat bottom wall 44a, a curved wall 44b that continuously covers the front and rear sides of the bottom wall 44a and the outside in the vehicle width direction, and an outer edge portion of the bottom wall 44a and the curved wall 44b. It has an extended joint flange 44c and. A bolt insertion hole 45 (see FIG. 10) is formed in the bottom wall 44a. A nut 46 is welded and fixed on the bottom wall 44a. A bolt (not shown) for fixing the subframe inserted from below into the bolt insertion hole 45 is screwed into the nut 46. As shown in FIG. 10, the joint flange 44c is welded and fixed to the outer surface (outer surface in the vehicle width direction) of the lower region of the inner side wall 20 of the frame body 2A and the lower surface of the lower wall 28, and the joint flange 44c of the frame body 2A. Below the lower joint flange 2Ab, it is welded and fixed to the lower edge of the outer plate 2B.

As shown in FIG. 10, the joint flange 44c on the front side of the mount bracket 44 is welded and fixed at a position sandwiched between a pair of recesses 31 on the front side frame 2 in the front-rear direction of the vehicle body. However, the front joint flange 44c (welded portion w) is not welded and fixed to the downward inclined wall 26 provided with the recessed portion 31 and the bulging portion 32 (non-fixed state), and the lower wall 28 is the second. It is welded and fixed to the lower surface of the partition region 35 sandwiched between the 1 bending line 33 and the 2nd bending line 34.
In the present embodiment, the welded portion w of the joint flange 44c constitutes the fixing portion of the mount bracket 44.

Next, the end connecting portion 13 of the cross member 12 shown in FIGS. 2 and 3 will be described.
As is clear from the position of the insertion hole 43 of the bolt 42 in FIG. 1, the end joint portion 13 is fastened and fixed at a position on the front side of the vehicle body rather than the position of the bending promotion portion 14 in the front side frame 2. To. The end joint portion 13 includes an insertion hole 47 into which the shaft portion of one bolt 42 is inserted, and a notch groove 48 into which the shaft portion of the other bolt 42 is inserted. The insertion hole 47 and the notch groove 48 are arranged side by side in the end joint portion 13, and the notch groove 48 is located on the rear side of the insertion hole 47 (the side close to the bending promoting portion 14). The notch groove 48 opens in a substantially U shape on the outside in the vehicle width direction. The end joint portion 13 has a front side by inserting the shaft portion of the bolt 42 into the insertion hole 47 and the notch groove 48, respectively, and tightening each bolt 42 to the collar 41 (see FIG. 6) in the front side frame 2. It is fixed to the frame 2. Since the notch groove 48 is open toward the outside in the vehicle width direction, when the front side frame 2 tries to bend and deform outward in the vehicle width direction about the bending promotion portion 14, the bolt 42 from the notch groove 48 Allows the shaft to come off. In the present embodiment, the insertion hole 47 constitutes the first joint portion, and the notch groove 48 constitutes the second joint portion.

In the above configuration, when an impact load in the vehicle front-rear direction is input to the front side frame 2, the front side frame 2 attempts to bend and deform outward in the vehicle width direction centering on the bending promoting portion 14 of the inner side wall 20, and is moved upward. The load is concentrated in the vicinity of the bending promoting portion 14 of the ridge line portion 21 and the lower ridge line portion 25. As a result, the vicinity of the bending promoting portion 14 of the upper ridge line portion 21 and the lower ridge line portion 25 starts bending deformation toward the outside in the vehicle width direction together with the bending promoting portion 14 of the inner side wall. At this time, in the lower inclined wall 26 adjacent to the lower ridge line portion 25, there are two locations so as to be recessed in the closed cross section of the front side frame 2 centering on each recess portion 31 located in front of and behind the bending promoting portion 14. Start the transformation with. As a result, a wide area in the vicinity of the bending promoting portion 14 of the front side frame 2 is deformed in multiple directions, and the energy of the impact load is absorbed during the deformation.

In this way, when the front side frame 2 begins to bend and deform outward in the vehicle width direction with the bending promoting portion 14 as the center, subsequently, the front region and the rear region of the front side frame 2 become the front bending promoting portion 15 and the rear, respectively. The side bending promoting portion 16 is bent and deformed inward in the vehicle width direction (see the virtual lines in FIGS. 1 and 2). As a result, the front side frame 2 is alternately bent in the vehicle width direction in a plurality of regions in the front-rear direction, and buckling deformation is promoted in a wide range of the front side frame 2. As a result, the energy of the impact load is efficiently absorbed in a wide range of the front side frame 2.

In the vehicle body front structure of the present embodiment, when an impact load is input, the lower inclined wall 26 is recessed in the front and rear of the bending promoting portion 14 together with the bending deformation of the inner side wall 20 of the front side frame 2 at the bending promoting portion 14. It is deformed so as to be depressed in the cross section centering on the portion 31. Therefore, when an impact load is input, a wide range in the vicinity of the bending promoting portion 14 of the front side frame 2 can be deformed in multiple directions. Therefore, when the vehicle body front structure of the present embodiment is adopted, the energy of the impact load can be efficiently absorbed without adding many members.

Further, in the vehicle body front structure of the present embodiment, the mount bracket 44 for attaching the subframe to the front side frame 2 is provided in two recesses 31 on the lower inclined wall 26 of the front side frame 2 in the front-rear direction of the vehicle body. It is fixed in the sandwiched position. Therefore, when the impact load is input, the fixed portion of the mount bracket 44 does not hinder the deformation of each recessed portion 31. Therefore, when this configuration is adopted, the energy of the impact load can be stably absorbed by the deformation of the front side frame 2.

Further, in the vehicle body front structure of the present embodiment, a bulging portion 32 that bulges inward in the vehicle width direction is provided in a region of the lower inclined wall 26 of the front side frame 2 sandwiched between the front and rear recesses 31. Has been done. Therefore, when the impact load is input, the front and rear recessed portions 31 of the downward inclined wall 26 are likely to be deformed individually so as to be depressed in the cross section of the front side frame 2 leaving the bulging portion 32. Therefore, when this configuration is adopted, the energy of the impact load can be absorbed more efficiently by the front side frame 2.

Further, in the present embodiment, a lower wall 28 extending substantially horizontally in the vehicle width direction is continuously provided at the lower end of the lower inclined wall 26 provided with the recessed portion 31 and the bulging portion 32, and the lower wall 28 is on the front side. A partition area 35 is provided which is partitioned by the first bend line 33 and the second bend line 34 on the rear side. The first bending line 33 and the second bending line 34 extend in the vehicle width direction so that the extension lines of the respective lines pass near the centers of the front and rear recessed portions 31 in the front view of the lower wall 28. Therefore, when the front and rear recesses 31 of the front side frame 2 are about to be deformed at the time of inputting the impact load, the lower edge of each recess 31 is stably supported by the partition region 35. Become. Therefore, when this configuration is adopted, it is possible to stabilize the deformation of each recessed portion 31 in the depressed direction when an impact load is input.

Further, in the vehicle body front structure of the present embodiment, the mount bracket 44 for attaching the subframe to the front side frame 2 is not fixed to the downward inclined wall 26 provided with the recessed portion 31 and the bulged portion 32. , Is fixed to the compartmentalized area 35 of the lower wall 28. Therefore, the deformation of the recessed portion 31 at the time of inputting the impact load is not hindered by the fixed portion of the mount bracket 44. Therefore, when this configuration is adopted, the impact load can be reliably absorbed by the stable deformation of the front side frame 2.

Further, in the vehicle body front structure of the present embodiment, the upper ridge line portion 21 and the lower ridge line portion 25 of the front side frame 2 are sandwiched between the front recessed portion 31 and the rear recessed portion 31 in the vehicle body front-rear direction. A bent portion 30 is provided at the provided position. Therefore, the bending deformation in the horizontal direction of the upper ridge line portion 21 and the lower ridge line portion 25 at the time of inputting the impact load can be promoted by the bending portion 30. Therefore, when this configuration is adopted, the bending promoting portion 14 substantially in the center in the front-rear direction of the front side frame 2 can be deformed at an early stage at the initial stage of inputting the impact load.

Further, in the case of the vehicle body front structure of the present embodiment, a concave groove 36 extending substantially horizontally from the front end to the rear end is formed on the inner side wall 20 of the front side frame 2. Therefore, the concave groove 36 can increase the bending deformation resistance of the front side frame 2 when an impact load is input. Therefore, when this configuration is adopted, the energy of the impact load can be efficiently absorbed by the plastic deformation of the front side frame 2.

Further, in the case of the present embodiment, a positioning hole 38 used at the time of press working is formed in a region excluding the bending promoting portion 14 at the bottom of the concave groove 36 of the frame main body 2A. Therefore, at the time of press molding of the frame body 2A, the plate material of the material can be accurately positioned on the press machine by using the positioning hole 38.

Further, in the present embodiment, since the frame body 2A and the outer plate 2B of the front side frame 2 are formed of a high-strength steel plate of at least 980 MPa or more, the front side frame 2 is less likely to be broken and deformed by the lightweight high-strength steel plate. can do.

Further, in the vehicle body front structure of the present embodiment, the partition wall members 39A and 39B for reinforcing the cross section of the front side frame 2 are connected to the inner surface of the front side frame 2 in the region where the recessed portion 31 does not exist. Therefore, it is possible to prevent the partition wall members 39A and 39B from hindering the deformation of the recessed portion 31 in the depressed direction when the impact load is input. Therefore, when this configuration is adopted, the impact load can be reliably absorbed by the stable deformation of the front side frame 2.

Further, the vehicle body front structure of the present embodiment is a front portion in which a fastening bolt 42 is inserted into an end connecting portion 13 of a cross member 12 arranged on the front side of a bending promoting portion 14 of the front side frame 2. An insertion hole 47 on the side and a notch groove 48 on the rear side are provided side by side. Therefore, when the front side frame 2 tries to bend and deform outward in the vehicle width direction around the bending promoting portion 14 at the time of inputting an impact load, the insertion hole 47 side of the end joint portion 13 becomes the front side frame 2. The notch groove 48 side can be separated from the front side frame 2 while being fixed. Therefore, when this configuration is adopted, it is possible to prevent the cross member 12 from hindering the bending deformation centered on the bending promoting portion 14 of the front side frame 2 when the impact load is input. As a result, when the impact load is input, the front side frame 2 can be reliably deformed as desired.

Further, in the case of the vehicle body front structure of the present embodiment, in the front side frame 2, the outer plate 2B is joined to the frame body 2A having a substantially hat-shaped cross section so as to close the opening of the frame body 2A, and the frame body 2B is joined. The plate thickness of 2A is set to be thicker than the plate thickness of the outer plate 2B. When the impact load is input to the front side frame 2, the upper ridge line portion 21 and the lower ridge line portion 25 of the frame body 2A are deformed in a substantially shape in the closed cross section to absorb the energy of the impact load. In this configuration, since the wall thickness of the frame body 2A, which is a cross-sectional member of the hat, is set to be thicker than the wall thickness of the outer plate 2B, a larger energy can be absorbed by the deformation of the frame body 2A.

Further, in the case of the present embodiment, recessed grooves 36, 37 extending linearly in a substantially horizontal direction from the front end to the rear end in the front-rear direction of the vehicle body are formed on both the frame body 2A and the outer plate 2B of the front side frame 2. Therefore, the bending deformation resistance of the front side frame 2 at the time of inputting the impact load can be further increased. Therefore, when this configuration is adopted, the energy of the impact load can be more efficiently absorbed by the plastic deformation of the frame body 2A and the outer plate 2B.

Further, the vehicle body front structure of the present embodiment includes a front bending promoting portion 15 and a rear bending promoting portion 15 that facilitate bending deformation inward in the vehicle width direction on the front side and the rear side of the bending promoting portion 14 of the front side frame 2. A portion 16 is provided. Therefore, when the impact load is input, the front bending promoting portion 15, the bending promoting portion 14, and the rear bending promoting portion 16 serve as the starting points of the bending deformation, and the front side frame 2 is largely alternately bent and deformed in the substantially horizontal direction. Can be done. Therefore, when this configuration is adopted, the energy of the impact load can be efficiently absorbed by the front side frame 2.

Further, in the vehicle body front structure of the present embodiment, the front side frame 2 and the front end portion of the lower member 5 are connected by the outriggers 6, and the first extension 8 and the second extension 9 which are energy absorbing members are interposed in front of the outriggers 6. The bumper beam 10 is attached. Therefore, when an impact load is input to the bumper beam 10, the impact load is transmitted to the front side frame 2 and the lower member 5 while deforming the bumper beam 10 and the first and second extensions 8 and 9. The front side frame 2 can be flexed and deformed in a substantially horizontal direction, and the lower member 5 can also be deformed at the same time. Therefore, when this configuration is adopted, the energy of the impact load can be absorbed more efficiently due to the deformation of each member.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist thereof. For example, in the above embodiment, the pair of recesses 31 and the bulge 32 are formed only on the lower inclined wall 26 of the front side frame 2, but the pair of recesses 31 and the bulge 32 are upwardly inclined walls. It may be formed in 22 as well. Further, the pair of recessed portions 31 and bulged portions 32 may be formed only on the upward inclined wall. In these cases, the partition area 35 partitioned by the first bending line 33 and the second bending line 34 may be provided on the upper wall 24. In this case, the upper wall 24 constitutes a substantially horizontal wall.

Further, in the above embodiment, since the cross member is fixed to the front side of the bending promoting portion 14 of the front side frame 2, the second joint portion is cut on the rear side of the end joint portion 13 of the cross member. The notch groove 48 is arranged, and the insertion hole 47 which is the first fastening portion is arranged on the front side. However, when the cross member is fixed to the rear side of the bending promoting portion 14 of the front side frame 2, the notch groove 48 is arranged on the front side of the end joint portion 13, and the insertion hole 47 is placed on the rear side. Just place it. Further, the configuration of the second joint portion is not necessarily limited to the notch groove 48. For example, the second joint portion may have a thin wall formed on the outer edge portion in the vehicle width direction of the insertion hole into which the shaft portion of the bolt is inserted.

Further, in the case of the above embodiment, in the front side frame 2, the frame main body 2 has an upper wall 24, an upper inclined wall 22, an inner side wall 20, a lower inclined wall 26, and a lower wall 28, and closes the opening of the frame main body 2. Together with the outer plate 2B, it has a hexagonal cross-sectional shape as a whole. However, the front side frame 2 may have a cross-sectional shape other than the hexagonal shape as long as it has a polygonal shape having at least an inner side wall, an upward inclined wall, and a downward inclined wall.

2 ... Front side frame 2A ... Frame body 2 (hat cross-section member)
2B ... Outer plate (closed plate member)
5 ... Lower member 6 ... Outrigger (connecting member)
8 ... 1st extension (energy absorbing member)
9 ... 2nd extension (energy absorbing member)
10 ... Bumper beam 12 ... Cross member 13 ... End joint 14 ... Bending promotion part 15 ... Front bending promotion part 16 ... Rear bending promotion part 20 ... Inner side wall 21 ... Upper ridge line part 22 ... Upper ridge wall 25 ... Lower ridge line Part 26 ... Lower sloping wall 28 ... Lower wall (approximately horizontal wall)
31 ... Recessed portion 32 ... Swelling portion 33 ... First bending line 34 ... Second bending line 35 ... Section area 36, 37 ... Recessed groove 38 ... Positioning holes 39A, 39B ... Partition member 44 ... Mount bracket 47 ... Insertion hole ( 1st joint)
48 ... Notch groove (second joint)

Claims (15)

It has a front side frame that extends substantially along the front-rear direction of the vehicle body and has a polygonal cross-sectional shape that intersects the front-rear direction of the vehicle body.
The front side frame
The inner side wall facing inward in the vehicle width direction and
An upward sloping wall extending outward and upward in the vehicle width direction from the upper ridge line at the upper end of the inner wall surface,
It has a downward sloping wall extending outward and downward in the vehicle width direction from the lower ridge line portion at the lower end of the inner wall surface.
The inner side wall is provided with a bending promoting portion that extends in the vertical direction of the vehicle body and facilitates bending deformation of the inner side wall in the vehicle width direction.
A pair of recesses recessed inward in the cross section of the front side frame is provided at the front-rear position of at least one of the upward-sloping wall and the downward-sloping wall in the front-rear direction of the vehicle body sandwiching the bending promoting portion. The front structure of the car body is characterized by being Further equipped with a mounting bracket that is fixed to the front side frame and to which a subframe can be attached.
The vehicle body front structure according to claim 1, wherein the mount bracket is fixed at a position sandwiched between the pair of recesses of the front side frame in the vehicle body front-rear direction. On the side of the upward inclined wall and the downward inclined wall where the pair of the recessed portions is provided, a bulging portion that bulges inward in the vehicle width direction is provided between the pair of the recessed portions. The vehicle body front structure according to claim 1 or 2, wherein the vehicle body is provided. A substantially horizontal wall that bends and extends outward in the vehicle width direction is continuously provided at an end portion of the inclined wall provided with the pair of the recessed portion and the bulging portion on the opposite side of the inner side wall.
The substantially horizontal wall is provided with a partition area partitioned by a first bending line on the front side and a second bending line on the rear side at front and rear positions sandwiching the bending promoting portion.
3. The first bending line and the second bending line are characterized in that, in a front view of the substantially horizontal wall, their extension lines extend in the vehicle width direction so as to pass through the recessed portions. The front structure of the car body described in. Further equipped with a mounting bracket that is fixed to the front side frame and to which a subframe can be attached.
The mount bracket is not fixed to the inclined wall provided with the pair of recessed portions and the bulged portion, and is fixed to the compartmentalized area of the substantially horizontal wall. The vehicle body front structure according to claim 4, wherein the vehicle body front structure is characterized by this. Claims 1 to 5 are characterized in that at least one bent portion is provided at a position in the vehicle body front-rear direction sandwiched between the pair of the recessed portions of the upper ridge line portion and the lower ridge line portion. The vehicle body front structure according to any one of the above items. The vehicle body front structure according to any one of claims 1 to 6, wherein the inner side wall has a concave groove extending linearly in a substantially horizontal direction from a front end to a rear end in the vehicle body front-rear direction. The vehicle body front structure according to claim 7, wherein the front side frame has a positioning hole formed in a region of the bottom of the concave groove excluding the bending promoting portion, which is used during press working. The vehicle body front structure according to any one of claims 1 to 8, wherein the front side frame is formed of a high-strength steel plate of at least 980 MPa or more. The front side frame has a built-in partition wall member that reinforces the cross section of the front side frame from the inside.
The vehicle body front structure according to claim 2 or 5, wherein the partition member is connected to a region of the inner surface of the front side frame where the recess does not exist. Further equipped with a cross member for mounting parts erected on the front side frame,
The cross member includes an end joint portion fixed to the front side or the rear side of the bending promoting portion of the front side frame.
The end joint includes a first joint on the front side frame that is located on the side away from the bend-promoting portion and a second joint that is located on the side that is close to the bend-promoting portion. Have
Claims 1 to 1, characterized in that the second coupling portion has a configuration capable of releasing the coupling with the front side frame according to the deformation of the front side frame centered on the bending promoting portion. The vehicle body front structure according to any one of 10. The front side frame
A hat cross-section member that opens in the vehicle width direction,
A closing plate member that is coupled to the side of the opening of the hat cross-section member and closes the opening.
The vehicle body front structure according to any one of claims 1 to 11, wherein the plate thickness of the hat cross-section member is set to be thicker than the plate thickness of the closing plate member. The front portion of the vehicle body according to claim 12, wherein the hat cross-sectional member and the closing plate member are formed with a concave groove extending linearly in a substantially horizontal direction from the front end to the rear end in the front-rear direction of the vehicle body. Construction. The front side frame
A front bending promoting portion is provided on the front side of the vehicle body with respect to the bending promoting portion to facilitate bending deformation inward in the vehicle width direction.
The invention according to any one of claims 1 to 13, wherein a rear bending promoting portion is provided on the rear side of the vehicle body with respect to the bending promoting portion to facilitate bending deformation inward in the vehicle width direction. The front structure of the car body. The lower member arranged on the outside in the vehicle width direction of the front side frame and
A connecting member that connects the front end of the front side frame and the front end of the lower member,
The bumper beam placed in front of the vehicle and
The vehicle body front structure according to any one of claims 1 to 14, further comprising an energy absorbing member interposed between the bumper beam and the connecting member.

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