JP5879205B2 - Body frame structure - Google Patents

Description

  The present invention relates to a body frame structure on the front side or rear side of a passenger compartment of a four-wheel vehicle.

  In a vehicle such as an automobile, at the time of a frontal collision of the vehicle, a lower member located behind the front cross member is bent downward to displace suspension parts such as a stabilizer supported by the lower member downward, thereby There is one in which the front crash stroke is ensured (see Patent Document 1).

In addition, as a technology to ensure a crash stroke at the time of a frontal collision of the vehicle, a subframe that supports suspension parts is provided on the lower side of the front part of the vehicle body, and the vehicle body fixing part on the rear side of the subframe is forcibly provided at the frontal collision of the vehicle. What was made to isolate | separate automatically is known (refer patent document 2).
In the vehicle body frame structure described in the cited document 2, the rear end portion of the sub-frame is fastened and fixed to the passenger compartment frame by bolts and nuts, and the nut is loosened by the thrust of the explosive during a frontal collision of the vehicle. Is provided. When this body frame structure is adopted, if the rotating lever arm loosens the nut due to the gunpowder thrust during the frontal collision of the vehicle, the rear end of the subframe falls downward together with the bolts, so that the mounted suspension parts move downward. Will be displaced.

JP 2010-247598 A US Patent Application Publication No. 2010/0004826

In the former technique, when a collision load in the vehicle front-rear direction is input, the lower member is bent and deformed downward, so that the suspension component supported by the lower member is less likely to interfere with the vehicle compartment side member during a collision. However, when the deformation of the vehicle body due to the collision proceeds, the lower member and the suspension parts cannot be reliably guided below the passenger compartment.
That is, in the former technique, since the lower member is bent at a substantially middle portion in the front-rear direction, the vehicle body connecting portion on the base end side of the lower member is maintained at a substantially constant position even if the deformation of the vehicle body front proceeds. Lower members and suspension parts are less likely to sink under the passenger compartment.

  In the latter technique, when a collision load in the longitudinal direction of the vehicle is input, the nut of the bolt fastening portion is loosened by the propellant thrust, thereby pulling out the bolt for fastening the subframe. Although the end portion of the frame can be completely detached from the vehicle body, the structure of the fastening portion at the end portion of the sub-frame is complicated, which tends to cause an increase in the weight of the vehicle and an increase in product cost.

  Therefore, the present invention enables the sub-frame to be surely guided to the lower side of the passenger compartment when a collision load in the vehicle longitudinal direction is input with a simple configuration, so that the vehicle weight is not increased and the product cost is not increased. An object of the present invention is to provide a vehicle body frame structure capable of increasing the crash stroke.

The vehicle body frame structure according to the present invention employs the following configuration in order to solve the above problems.
According to the first aspect of the present invention, a side frame (for example, the front side frame 11 of the embodiment) disposed along the front-rear direction of the vehicle body on the front side or the rear side of the passenger compartment, and the lower side of the side frame. A sub-frame (for example, sub-frame 22 of the embodiment) that supports the suspension component, and a vehicle that is disposed outside and below the front or rear of the vehicle compartment and supports the end of the sub-frame that is close to the vehicle compartment. A floor-side support member (for example, the lateral member 20 of the embodiment) and a step portion (for example, the step portion 55 of the embodiment) adjacent to the floor tunnel portion (for example, the floor tunnel portion 18 of the embodiment) of the passenger compartment. A lower floor frame (for example, the front end extension member 10 and the floor tunnel frame 15 of the embodiment) disposed below the vehicle body in the longitudinal direction of the vehicle body, and the subframe A link stay (for example, link stay 30 of the embodiment) that is disposed across an end portion on the side close to the passenger compartment and the lower floor frame, and connects the two. A separation side fastening portion (for example, the front fastening portion 22m in the embodiment) fastened to a member on the extending end side of the side frame at an end portion on the side separated from the vehicle, and the end portion on the side close to the passenger compartment. A proximity side fastening portion (for example, the rear fastening portion 22u of the embodiment) fastened and fixed to the passenger compartment side support member from the lower side, and a substantially central portion in the front-rear direction between the separation side fastening portion and the proximity side fastening portion The link stay can be pulled out on the lower surface of the vehicle compartment side support member at the one end side together with the proximity side fastening portion at the center folding point (for example, the central folding point 27 in the embodiment). And the other end side The link is fastened to the lower floor frame by a support bolt extending in the vehicle width direction (for example, the support bolt 39 of the embodiment) and a nut (for example, the nut 38 of the embodiment) screwed to the support bolt. The nut that fastens the other end of the stay is held on a side wall of the link stay that is separated from the floor tunnel part (for example, the side wall 30so in the embodiment), and the support bolt is attached to the floor tunnel part. The nut is fastened to the nut from the lower side.
In the case of the present invention, when a collision load in the longitudinal direction of the vehicle body is input to the extended end side of the side frame, the collision load is also input to the separation side fastening portion of the subframe while the side frame is compressively deformed. When a collision load is input to the separation side fastening portion, the subframe is bent downward at the center folding point, and the proximity side fastening portion is pulled out below the vehicle compartment side support member together with the one end portion side of the link stay. When the deformation accompanying the collision further proceeds from this state, the end portion of the subframe on the passenger compartment side rotates downward together with the link stay about the support bolt.
Further, when the other end of the link stay is fastened to the lower floor frame when the vehicle body is assembled, the support bolt is tightened to the nut at a position below the floor tunnel portion.

According to a second aspect of the present invention, in the vehicle body frame structure according to the first aspect, the nut includes an engaging claw (for example, the engaging claw 65c of the embodiment) that is engaged with a side wall of the link stay. (For example, the nut cover 65 of the embodiment) is integrally assembled.
In this case, when the other end portion of the link stay is fastened to the lower floor frame, the engaging claw of the nut cover integrated with the nut is locked in advance on the side wall of the link stay, and in this state the nut cover Tighten the support bolt to the inner nut.

According to a third aspect of the present invention, in the vehicle body frame structure according to the first or second aspect, the side wall of the link stay has a bolt insertion portion (for example, the notch groove 30m of the embodiment) through which the support bolt is inserted. The nut is provided with a restriction protrusion (for example, a restriction protrusion 67 of the embodiment) that is locked to the bolt insertion portion of the side wall of the link stay and restricts rotation. is there.
In this case, when the support bolt is tightened into the nut, a torque reaction force acts on the nut from the link stay via the restricting projection.

According to a fourth aspect of the present invention, in the vehicle body frame structure according to any one of the first to third aspects, a bolt insertion portion (for example, the cut-off portion of the embodiment) through which the support bolt is inserted into the side wall of the link stay. A notch groove 30m) is provided, and the bolt insertion portion is a displacement that allows relative displacement between the link stay and the support bolt accompanying displacement of the subframe in the longitudinal direction of the vehicle body when a collision load in the longitudinal direction of the vehicle body is input. An allowable portion (for example, the displacement allowable portion 60 of the embodiment) is provided.
In this case, when the collision load in the longitudinal direction of the vehicle body is initially input, if the near side fastening portion of the subframe is displaced in the direction of approaching the bottom floor frame as the side frame is crushed, it is locked to the bottom floor frame side. The displacement of the link stay relative to the supported support bolt is allowed by the displacement allowance portion. Accordingly, at this time, an excessive load is not generated from the support bolt to the link stay, and unnecessary deformation of the link stay is suppressed.

The invention according to claim 5 is the vehicle body frame structure according to any one of claims 1 to 4, wherein a side wall of the link stay is provided with a bolt insertion portion through which the support bolt is inserted. It is constituted by a notch groove (for example, the notch groove 30m of the embodiment) that allows the link stay to fall off from the support bolt accompanying the downward displacement of the subframe when a collision load in the longitudinal direction of the vehicle body is input. It is characterized by this.
In this case, after the input of the collision load in the longitudinal direction of the vehicle body, after the subframe rotates around the axis of the support bolt via the link stay, the support bolt is relatively displaced toward the opening side of the notch groove. The link stay is displaced downward. As a result, the engagement of the link stay with the support bolt is released, and the vehicle compartment side region of the subframe falls downward together with the link stay.

According to the first aspect of the present invention, when a collision load in the longitudinal direction of the vehicle body is input, the subframe bends downward at the center folding point, and the proximity side fastening portion together with the one end portion side of the link stay is the vehicle compartment side support member Since the rear part of the subframe is pivoted around the support bolts on the lower floor frame together with the link stay, the subframe and suspension parts are reliably guided below the passenger compartment. Can do.
Therefore, according to the present invention, although the structure is simple, the subframe and the suspension component can be reliably guided to the lower side of the vehicle compartment when inputting the collision load in the longitudinal direction of the vehicle body. The crash stroke of the vehicle can be increased without causing an increase in product cost.
Further, according to the present invention, the nut is held on the side wall on the side away from the floor tunnel portion of the link stay, and the support bolt is tightened to the nut from the lower side of the floor tunnel portion. There is an advantage that the work of tightening the support bolt with respect to the nut can be easily performed in a wide space below the tunnel portion, thereby improving workability

  In the invention according to claim 2, since the nut is integrally assembled to the nut cover having the engaging claw, the nut cover is locked in advance at a predetermined position on the side wall of the link stay. Even when the space on the side of the arrangement is narrow, the support bolt can be tightened with the nut positioned accurately.

  In the invention according to claim 3, since the nut is provided with a restricting projection that is locked to the bolt insertion portion and restricts the rotation of the nut, the support bolt is fastened to the nut without the operator pressing the nut portion. be able to.

  In the invention according to claim 4, since the displacement allowance portion is provided in the bolt insertion portion on the side wall of the link stay, the displacement of the link stay is suppressed when the near-side fastening portion of the subframe is displaced in the frame direction below the floor. It can accept | permit by a displacement tolerance part. Therefore, according to the present invention, it is possible to prevent unnecessary deformation of the link stay before the link stay functions as a link.

  In the invention according to claim 5, since the bolt insertion portion of the link stay is constituted by the notch groove, the subframe is arranged around the axis of the support bolt via the link stay in the latter half of the collision load input in the vehicle longitudinal direction. After the rotation, the link stay locked to the support bolt can be dropped downward along the notch groove. Therefore, according to the present invention, when the collision load in the longitudinal direction of the vehicle body is input, the compartment side region of the subframe can be finally dropped downward.

It is a partial section side view of the vehicle of this one embodiment. It is a bottom view of the front half area of the vehicle of this one embodiment. It is the perspective view which looked at the vehicle of this one embodiment from the compartment side. It is the perspective view which looked at the sub-frame of the vehicle of one Embodiment of this invention from the lower side. It is an expanded sectional view corresponding to the section of Drawing 1 of one embodiment of this invention. It is the perspective view which expanded a part of FIG. 3 of one Embodiment of this invention. It is the perspective view which looked at the attachment part of the link stay of one Embodiment of this invention from the lower side. It is a longitudinal cross-sectional perspective view which shows the attachment part of the link stay of one Embodiment of this invention. It is a perspective view which shows the attaching part of the upper attachment arm of one Embodiment of this invention. It is the perspective view which looked at the sub-frame of one Embodiment of this invention from the back by making a rear fastening part a cross section. It is the perspective view which looked at the link stay of one Embodiment of this invention from the downward direction. It is a side view of the link stay of one Embodiment of this invention. It is the perspective view which looked at the link stay of one Embodiment of this invention from the upper direction. It is a perspective view of the attachment part of the sub-frame and link stay of one Embodiment of this invention. It is a longitudinal cross-sectional view of the attachment part of the sub-frame and link stay of one Embodiment of this invention. It is sectional drawing corresponding to the AA cross section of FIG. 3 of one Embodiment of this invention. It is the perspective view which looked at the fastening part of the rear part side of the link stay of one Embodiment of this invention from the vehicle width direction outer side. It is the perspective view which looked at the fastening part of the rear part side of the link stay of one Embodiment of this invention from the vehicle width direction inner side. It is sectional drawing corresponding to the BB cross section of FIG. 17 of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention. It is explanatory drawing which shows the fall condition of the sub-frame of one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, “front”, “rear”, “upper”, “lower”, “left” and “right” are used for “front”, “rear”, “upper”, “upper” It means “down”, “left” and “right”.
FIG. 1 is a diagram showing a left side surface of a front side of a vehicle according to this embodiment with a part cut away, FIG. 2 is a diagram of the front region of the vehicle viewed from below, and FIG. FIG. 2 is a view of the front lower side of the vehicle as viewed from the diagonally upper side on the passenger compartment side.
As shown in these drawings, a rear end portion of a dash lower panel 17 that separates the compartment I from the front engine compartment E is joined to the front end of the floor panel 19 facing the compartment I. The dash lower panel 17 rises obliquely upward from the joint with the floor panel 19. In addition, a floor tunnel portion 18 that bulges upward is provided along the vehicle longitudinal direction at the center of the floor panel 19 in the vehicle width direction. The front end portion of the floor tunnel portion 18 is abutted against the dash lower panel 17. 2 and 3, illustration of the dash lower panel 17 is omitted.

  A pair of left and right front side frames 11, 11 (side frames), which are main frame members on the front side of the vehicle body, are provided in the front side of the passenger compartment I along the vehicle body front-rear direction. Both front portions of the front bulkhead 12 that supports a radiator (not shown) are attached to the front end portions of the front side frames 11 and 11. The front side frames 11 and 11 hold power units (not shown) for driving the vehicle.

As shown in FIG. 3, the rear end portion of the front side frame 11 is formed as a front side rear end 16 having a U-shaped cross section that is continuous with the closed cross-section structure portion on the front side and has an open top. The front side rear end 16 extends rearward of the vehicle body along the lower surface of the dash lower panel 17 and the lower surface of the floor panel 19. The front side rear end 16 is joined to the lower surfaces of the dash lower panel 17 and the floor panel 19 to form a continuous closed cross section along the longitudinal direction of the vehicle body. Further, the front side rear end 16 is connected to a side sill 14 which is a skeleton member on the side portion of the passenger compartment I by an outrigger 13 which is a frame member having a U-shaped cross section opening upward.
Reference numeral 21 in FIG. 3 denotes a floor center frame that is attached to the upper surfaces of the dash lower panel 17 and the floor panel 19 and forms a closed cross section that is continuous with the front side rear end 16 together with the panels 17 and 19.

On both sides of the floor tunnel portion 18 below the passenger compartment I, floor tunnel frames 15 and 15, which are frame members having a U-shaped cross-section opening upward, are arranged along the longitudinal direction of the vehicle body. A front end extension member 10 having a continuous U-shaped cross section is joined to the front end portion of each floor tunnel frame 15. A floor panel 19 and a dash lower panel 17 are joined to the upper surface side of the floor tunnel frame 15 and the front end extending member 10. The floor tunnel frame 15 and the front end extension member 10 together with the floor panel 19 and the dash lower panel 17 constitute a closed cross section along the vehicle body longitudinal direction.
In this embodiment, the floor tunnel frame 15 and the front end extending member 10 constitute a lower floor frame.

  Further, the front side rear end 16 on the left and right in the vehicle width direction and the front end extension member 10 (floor lower frame) adjacent to the front side rear end 16 are connected to each other by a lateral member 20. The lateral member 20 is a plate-like member having a U-shaped cross section that opens upward, and extends along the vehicle width direction so as to be continuous with the outrigger 13.

Accordingly, the dash lower panel 17 is joined to the upper surface of the front side rear end 16, thereby forming a closed cross section along the vehicle body front-rear direction that is continuous with the front side frame 11, and joined to the upper surfaces of the outrigger 13 and the lateral member 20. As a result, a closed cross section is formed along the vehicle width direction connecting the side sill 14 and the front side rear end 16 and the front side rear end 16 and the floor tunnel frame 15 respectively.
The front side rear end 16, the outrigger 13, and the lateral member 20 have flange portions at the upper part of the open cross section, and these flange portions are joined to the lower surfaces of the floor panel 19 and the dash lower panel 17.

Below the front side frames 11, 11, a sub-frame 22 that supports suspension parts (not shown) is attached.
FIG. 4 is a view of the subframe 22 as viewed from below.
As shown in the figure, the sub-frame 22 has front fastening portions 22m and 22m (separated from each other) fastened to the front bulkhead 12 attached to the front end portions (extending ends) of the left and right front side frames 11 and 11. Side fastening portion), rear fastening portions 22u, 22u (close-side fastening portions) fastened and fixed to the lateral member 20 below the front portion of the passenger compartment I, and when a longitudinal collision load is input to the vehicle In addition, central folding points 27 and 27 that bend downward at a substantially central position in the front-rear direction between the front fastening portions 22m and 22m and the rear fastening portions 22u and 22u, and central folding points 27 and 27 at positions near the rear side. And upper mounting arms 25, 25 that are provided and fastened to the lower surfaces of the front side frames 11, 11.

  The sub-frame 22 includes a sub-frame main body 23 cast from an aluminum alloy, a pair of left and right extension arms 24 that extend from the both sides of the front end of the sub-frame main body 23 to the front side and are press-formed with a light alloy or steel. And 24. An electric power steering device EPS (see FIG. 1) is arranged on the upper surface side of the subframe body 23.

  As shown in FIG. 2, the subframe body 23 has a rear edge that is curved so that the center portion is recessed in a plan view, left and right side edges that open outwardly and extend linearly, and a vehicle width. It is a member of the shape provided with the front edge extended linearly in a direction. The sub-frame main body 23 is provided with a plurality of vertical ribs (see FIG. 4) on the lower surface side, thereby reducing weight and improving rigidity. The rear fastening portions 22u and 22u are provided at the left and right ends of the rear side of the subframe body 23, and the upper mounting arms 25 and 25 are provided at the left and right ends of the front side of the subframe body 23. ing.

The rear end portions of the left and right extension arms 24 are fixed to the lower surface on the front end side of the subframe main body 23 by a plurality of bolts 26. The front edge portion of each extension arm 24 is the above-described front fastening portion 22m of the sub-frame 22, and the front fastening portion 22m is fastened and fixed to the lower corner portion of the front bulkhead 12 by a bolt 26. ing.
As shown in FIG. 1, the vicinity of the fastening portion between each extension arm 24 and the subframe main body 23 is constricted when viewed from the side. This constricted portion is the above-described central break point 27. The center folding point 27 does not normally bend at all, but when a longitudinal collision load F greater than a predetermined value is input to the vehicle, the subframe 22 bends downward at the approximate center in the longitudinal direction. The starting point. Here, as shown in FIG. 1, each of the left and right extension arms 24 has a ground height on the front end side higher than a ground height on the rear end side in a state where the subframe 22 is mounted on the vehicle.

FIG. 5 is an enlarged view showing a connecting portion between the rear fastening portion 22u of the subframe main body 23 and the lower region on the front side of the passenger compartment I.
As shown in the figure, the left and right rear fastening portions 22u of the sub-frame main body 23 are configured by thick cylindrical boss portions protruding to the upper surface side and the lower surface side. Each rear fastening portion 22u is provided with an extension piece 29 projecting from the rear fastening portion 22u in the direction of the front end extending member 10 (downward frame direction). The extension piece 29 is formed in an arc shape on a plan view, and the lower surface side is hollowed out in a hollow shape. Further, the distal end portion of the extension piece 29 faces the front surface of the front end extension member 10 with a predetermined gap in a state where the subframe 22 is attached to the vehicle body.

A link stay 30 is attached to the left and right rear fastening portions 22u and the left and right front end extending members 10 arranged on the rear side thereof.
The front edge portion of the link stay 30 is fastened and fixed to the lower surface of the corresponding rear fastening portion 22u so as to cover the lower side and both side portions of the rear fastening portion 22u. Specifically, the left and right rear fastening portions 22u of the subframe 22 are arranged on the lower surface of the mounting seat 32 of the left and right lateral members 20 below the front portion of the vehicle compartment I, and the front edge portion of the link stay 30 Are superimposed on the lower surface of the corresponding rear fastening portion 22u. In this state, the front edge part of the link stay 30 is fastened together with the corresponding rear fastening part 22u to the mounting seat 32 of the lateral member 20 by fastening bolts 31.
The front wall of the horizontal member 20 is formed so as to descend obliquely rearward, and the mounting seat 32 of the horizontal member 20 is formed substantially horizontally on a part of the lower wall. A weld nut 33 to which the front end portion of the fastening bolt 31 is screwed is fixed to the upper surface side of the mounting seat 32 of the horizontal member 20. The fastening bolt 31 penetrates the link stay 30, the rear fastening portion 22 u, and the lateral member 20 in a substantially vertical direction from the lower side of the link stay 30, and the tip end side thereof is fastened to the weld nut 33.

On the other hand, the front end extension member 10 (lower floor frame) whose front end portion is coupled to the horizontal member 20 is provided with a support wall 10a that is inclined obliquely upward and then bent substantially horizontally in a step shape. The front end portion of the extension piece 29 is opposed to the front surface of the support wall 10a with a predetermined gap when the subframe 22 is attached to the vehicle body. The distal end portion of the extension piece 29 comes into contact with the front surface of the support wall 10a when the rear fastening portion 22u of the subframe 22 is displaced rearward of the vehicle body when a collision load in the vehicle longitudinal direction is input.
5 is joined to the upper surface of the rising portion of the dash lower panel 17 above the joint between the front end extension member 10 and the lateral member 20, and the joint between the front end extension member 10 and the lateral member 20 is joined. Reinforcement reinforcement.

FIG. 6 is an enlarged view of the installation portion of the horizontal member 20 of FIG.
As shown in the figure, in a region straddling the upper surface of the mounting seat 32 of the horizontal member 20 and the inner surface of the side wall on the inner side in the vehicle width direction, a reinforcement made of a hot metal plate than the horizontal member 20 is used. The plate 35 is joined. The reinforcing plate 35 is formed with a relief hole 36 that surrounds the outside of the weld nut 33 on the lateral member 20 with a predetermined separation width. The periphery of the relief hole 36 of the reinforcing plate 35 is spot-welded to the upper surface of the lateral member 20 at a plurality of locations.
At least one of the spot welded portions of the reinforcing plate 35 is set at the nearest position immediately behind the escape hole 36. In FIG. 6, the spot welding point is indicated by a symbol S. This spot welding point S can accept that the reinforcing plate 35 moves rearward with respect to the mounting seat 32 when a collision load in the longitudinal direction of the vehicle body is input, as a force in the cutting direction that is advantageous in strength. it can.

The horizontal member 20 is reinforced by the reinforcing plate 35 as described above, but the weld nut 33 is in contact with only the region in the clearance hole 36 on the mounting seat 32 of the horizontal member 20, so that contact is made. The strength in the vertical direction of the peripheral area of the part is partially weakened. In particular, since the rigidity of the portion in contact with the edge of the relief hole 36 is enhanced by the reinforcing plate 35, when a vertical load is input to the fastening bolt 31, stress is applied to a narrow area around the weld nut 33. Is easy to concentrate. In this embodiment, an annular region between the escape hole 36 on the lateral member 20 and the weld nut 33 is a weakened portion Z.
Therefore, when an excessive load in the pulling direction acts on the fastening bolt 31 when a collision load in the longitudinal direction of the vehicle body is input, the fragile portion Z on the lateral member 20 is broken, and the fastening bolt 31 is moved below the lateral member 20. It will be pulled out.
In this embodiment, the lateral member 20 and the reinforcing plate 35 constitute a vehicle compartment side support member that supports the rear end portion of the subframe 22, and the lateral member 20 constitutes a support member substrate.

7 and 8 are views showing a fastening portion of the link stay 30 with respect to the subframe main body 23 and the front end extending member 10 (floor lower frame).
As shown in these drawings and FIG. 5, the front end extending member 10 is a member having a U-shaped cross section having both side walls 40 and a bottom wall 41 and having an open upper side, and between the rear side walls 40, 40. A support bracket 43 including a bolt holding portion 42 along the vehicle width direction is provided. The support bracket 43 includes the above-described bolt holding portion 42 formed by rolling a plate material into a cylindrical shape, an arm portion 44 extending obliquely downward rearward from the bolt holding portion 42, and horizontally bent and extended to the end of the arm portion 44. And a mounting portion 45 provided. The mounting portion 45 of the support bracket 43 is fixed by welding on the bottom wall 41 of the front end extending member 10. Through holes 50 are formed at positions corresponding to both end portions of the bolt holding portions 42 of the side walls 40, 40.

  As shown in FIG. 7, the front end extending member 10 is fastened and fixed to the side walls 30 so and 30 si (see FIG. 13) at the rear edge of the link stay 30 by support bolts 39. The support bolt 39 is inserted into the bolt holding portion 42 of the support bracket 43 through the through hole 50 of the side wall 40 of the front end extending member 10, and the nut 38 is screwed to the tip portion that penetrates the both side walls 40. The nut 38 is assembled inside a resin nut cover 65 as will be described later.

FIG. 9 is a view showing a fixing portion of the upper mounting arm 25 of the subframe main body 23, and FIG. 10 is a view showing fixing portions of the upper mounting arm 25 and the rear fastening portion 22u of the subframe main body 23.
As shown in these drawings, the upper mounting arm 25 includes an upper mounting arm main body 47 that extends upward, and a connection bracket 46 that is attached to the upper mounting arm main body 47. The upper mounting arm 25 is fixed to the lower surface of the front side frame 11 via a connection bracket 46. The connection bracket 46 is a member that is attached to the upper portion of the upper attachment arm main body 47 and is formed in an L shape toward the outside in a rear view. The connecting bracket 46 includes a base portion 49 fixed to the upper mounting arm main body 47 by two fixing bolts 48, 48 extending in the horizontal direction, and a front side frame by a single fixing bolt 48 extending in the vertical direction. 11, and an attachment portion 51 fixed to the lower surface of 11, thereby forming an L shape.

  In the base portion 49, an insertion hole 52 for the fixing bolt 48 is formed, and a cutout portion 53 that opens a part of the insertion hole 52 downward is formed. Therefore, when a load is applied that causes the upper mounting arm 25 to be pulled downward in the event of a vehicle collision, the connecting bracket 46 remains on the front side frames 11, 11, and the upper mounting arm main body 47 and the connecting bracket 46 are fixed. The fixing bolt 48 breaks the notch 53 and moves the upper mounting arm main body 47 downward, so that the subframe 22 is allowed to move downward.

11 to 15 are diagrams showing the detailed structure of the link stay 30.
As shown in these drawings, the link stay 30 is formed by a bottom wall 30t and both side walls 30so, 30si in a U-shaped cross section, and the bottom wall 30t at the front end is the rear fastening portion 22u of the subframe main body 23. At the same time, it is fastened together with the fastening bolt 31 to the mounting seat 32 of the lateral member 20, and the side walls 30so, 30si at the rear end are fastened to the front end extending member 10 at the front portion of the floor tunnel frame 15 by the support bolt 39 with the vehicle width direction as an axis. (See FIG. 7).

An upper edge flange portion 30f extending laterally is formed at the upper edge of the both side walls 30so, 30si of the link stay 30 to prevent opening. A V-shaped dent 30k is formed at the center in the front-rear direction at the upper edge of the side wall 30so on the outer side in the vehicle width direction, and the front side of the upper edge of the side wall 30so on the outer side in the vehicle width direction is an inclined part 30a that gradually falls forward. It has become.
The side wall 30si on the inner side in the vehicle width direction of the link stay 30 has the same shape as the side wall 30so on the outer side in the vehicle width direction from the rear end side to the position of the bottom of the V-shaped recess 30k of the side wall 30so on the outer side in the vehicle width direction. However, unlike the side wall 30so on the outer side in the vehicle width direction, the side wall 30so on the outer side in the vehicle width direction extends to the front end side with the height of the bottom of the V-shaped recess 30k.
The side walls 30so and 30si of the link stay 30 are arranged so as to sandwich the side walls 40 and 40 of the front end extension member 10 from the side (see FIG. 5).

  In the front portion of the link stay 30, a recessed portion 30 h is formed in which a part of the bottom wall 30 t is recessed upward and comes into contact with the lower surface of the mounting seat 32 of the lateral member 20. The recess 30h is formed so as to be inclined and dropped from the bottom surface position of the bottom wall 30t. The strength of the front side of the link stay 30 is increased by the recess 30h. A bolt hole 30y of the fastening bolt 31 is formed in the recess 30h.

  In the vicinity of the rear portion of the recessed portion 30h of the link stay 30, a downward convex portion 30x that is convex downward is formed by press molding. The downward convex portion 30x is disposed at a substantially central position in the front-rear direction of the link stay 30. As shown in FIG. 12, the downward convex portion 30x is a portion that slightly protrudes downward with respect to the straight line P when the front end portion and the rear end portion are connected by a straight line P when viewed from the side. Yes, this portion corresponds to the formation position of the V-shaped recess 30k formed at the upper edge of the side walls 30so, 30si in the front-rear direction. The downward convex portion 30x is a starting point for the link stay 30 to be bent. The downward convex portion 30x forms a ridge line in the width direction of the bottom wall 30t of the link stay 30.

  The side walls 30so and 30si on both sides of the rear portion of the link stay 30 are provided with notched grooves 30m that are notched with a certain width from the rear end to the front side. As shown in FIG. 7, the notch groove 30m is a groove in which the bolt holding portion 42 of the support bracket 43 and the shaft portion of the support bolt 39 inserted into the through hole 50 of the front end extension member 10 are supported in a penetrating state. is there. The rear end portion of the link stay 30 is fastened and fixed to the front end extension member 10 by tightening the support bolt 39 and the nut 38 outside the notch groove 30m of the side walls 30so and 30si. Therefore, the shaft portion of the support bolt 39 is configured as a fastening center O at the rear end portion of the link stay 30.

  Further, the bottom wall 30t at the rear end of the link stay 30 is provided with a notch 30n on the front side from the end edge. The notch 30n functions as a relief so that the bottom wall 30t does not interfere with the bottom wall 41 of the front end extension member 10 when the link stay 30 rotates downward about the fastening center O of the rear end of the stay. The link stay 30 is allowed to rotate.

FIG. 16 is a view showing a cross section including a fastening portion on the rear end side of the link stay 30 below the passenger compartment I.
As shown in FIG. 3 and FIG. 3, the dash lower panel 17 and the floor panel 19 below the passenger compartment I have a stepped portion 55 that is one step higher in the portion adjacent to the floor tunnel portion 18 in the center in the vehicle width direction. A region outside the vehicle width direction adjacent to 55 is connected to the side sill 14 with a substantially constant height. The step portion 55 extends along the longitudinal direction of the vehicle body so as to run in parallel with the floor tunnel portion 18. The floor tunnel frame 15 and the front end extending member 10 described above are joined to the upper wall lower surface 55a of the stepped portion 55. The side wall 30so on the outer side in the vehicle width direction of the link stay 30 attached to the front end extending member 10 is substantially parallel to the floor lower side surface 55b of the vertical wall of the step portion 55.

  Incidentally, as shown in FIG. 16, the rear edge portion of the link stay 30 is fastened and fixed to the front end extending member 10 by the support bolt 39 and the nut 38 described above. It is attached to the outer side wall 30so (side wall away from the floor tunnel portion 18) together with the nut cover 65, and the support bolt 39 is fastened to the nut 38 from the lower side of the floor tunnel portion 18 without the vertical wall of the step portion 55. It is included.

17 to 19 are views showing a state in which the support bolt 39 and the nut 38 are fixed to the rear edge portion of the link stay 30. In practice, the front end extension member 10 is interposed between the side walls 30so and 30si of the link stay 30, but in FIG. 17 to FIG. 19, the front end extension member 10 is not shown for the sake of illustration. ing.
The shaft portion of the support bolt 39 is fixed in position by tightening a nut 38 (see FIGS. 7 and 19) at a substantially intermediate position in the longitudinal direction of each notch groove 30m of the link stay 30.

As shown in FIG. 19, the nut 38 is integrally assembled with a resin nut cover 65.
As shown in FIGS. 7, 17, and 18, the nut cover 65 includes a substantially cylindrical cover main body 65a that wraps around the outer peripheral side of the nut 38, and an arm portion that protrudes radially outward from the outer peripheral side of the cover main body 65a. 65b, a pair of engaging claws 65c and 65c projecting at two spaced apart positions on the radially outer side of the arm portion 65b, and an end substantially opposite to the protruding direction of the arm portion 65b on the circumference of the cover body 65a And a locking projection 65d protruding from the portion. The engaging claws 65c, 65c and the locking protrusion 65d are provided on the end face of the cover body 65a on the side facing the side wall 30s of the link stay 30.

  As shown in FIGS. 7, 11, and 12, a pair of rectangular locking holes 66, 66 are formed in a portion of the side wall 30 so on the outer side in the vehicle width direction of the link stay 30 that is close to the notch groove 30 m. Is formed. Engaging claws 65c and 65c of a nut cover 65 in which the nut 38 is housed are inserted and engaged with the locking holes 66 and 66 from the outside of the side wall 30so. Further, when the engaging claws 65c and 65c are inserted into and engaged with the locking holes 66 and 66 in this way, the locking protrusion 65d protruding from the cover main body 65a is formed in the opening side region of the notch groove 30m of the side wall 30so. Mated. The nut cover 65 is held at a set position on the side wall 30so of the link stay 30 by engaging the engaging claws 65c, 65c and the locking protrusion 65d with the locking hole 66 and the notch groove 30m, respectively. Is done.

  As shown in FIGS. 18 and 19, the nut 38 is integrally formed with a restricting projection 67 that protrudes outward from the end face on the side wall 30so side of the cover body 65a. When the nut cover 65 is held on the side wall 30so as described above, the restricting projection 67 is a region on the opening side of the notch groove 30m of the side wall 30so (the region on the bottom side from the position where the locking projection 65d is fitted). ). As a result, the rotation of the nut 38 is directly regulated by the side wall 30so.

  The support bolt 39 is set in the notch groove 30m of the link stay 30 when the nut 38 and the nut cover 65 are positioned on the side wall 30so as described above and tightened into the nut 38. Fixed in position. As described above, this position is a substantially intermediate position in the longitudinal direction of the notch groove 30m. Therefore, in a state where the support bolt 39 and the nut 38 are fastened, a predetermined space is secured between the shaft portion of the support bolt 39 and the bottom portion of the notch groove 30m. The space portion serves as a displacement allowance portion 60 that allows relative displacement of the link stay 30 and the support bolt 39 accompanying the rearward displacement of the subframe 22 when a collision load in the longitudinal direction of the vehicle body is input.

  Here, as shown in FIG. 1, the positional relationship among the downward convex portion 30x of the link stay 30, the central folding point 27 of the subframe 22, and the rear fastening portion 22u of the subframe body 23 is the downward convex portion. The apex viewed from the side of 30x forms a truss structure that forms a triangle with the central folding point 27 of the subframe 22 and the rear fastening portion 22u, and the fastening center O between the central folding point 27 and the stay rear end of the link stay 30. Is located below a straight line L connecting the two. The rear fastening portion 22u is a mounting portion of the subframe main body 23, and the central folding point 27 is a bent portion. However, in the following description, when the rear fastening portion 22u is regarded as a node of the truss structure, the rear fastening portion 22u is a horizontal member. 20 means a joint portion with the mounting seat 32, and the center folding point 27 means the center of the extension arm 24 in the vertical direction.

FIG. 20 is a diagram showing the behavior of the rear portion of the subframe 22 in the initial stage of inputting the collision load in the longitudinal direction of the vehicle body, and FIG. 21 shows the behavior of the rear portion of the subframe 22 in the middle phase of inputting the collision load in the longitudinal direction of the vehicle body. FIG.
As shown in FIG. 20, when a collision load is input to the front portion of the subframe 22 and the center folding point 27 starts to bend, the rear edge of the rear fastening portion 22u of the subframe 22 on the lateral member 20 comes into contact. The portion becomes a mechanical fulcrum F1 (hereinafter referred to as “first fulcrum F1”), and a downward force is applied to the action point S1 immediately before the weld nut 33. That is, at the initial stage of input of the collision load, the mounting seat 32 portion of the lateral member 20 becomes the first fulcrum F1, and a force in the direction of pulling downward is applied to the fastening bolt 31.
In addition, the 1st fulcrum F1 is a part adjacent to the back side of the weak part Z on the horizontal member 20, This part is reinforced with the reinforcement board 35 as shown in FIG. 5, and rigidity is improved.

  On the other hand, as shown in FIG. 21, when a collision load is input to the front portion of the subframe 22 and the central folding point 27 starts to bend, the rear fastening portion 22u is accompanied by the inclination of the subframe body 23 and a slight rearward displacement. The tip of the extension piece 29 comes into contact with the support wall 10 a of the front end extension member 10. Thus, when the distal end portion of the extension piece 29 comes into contact with the support wall 10a, the contact portion becomes a mechanical fulcrum F2 (hereinafter referred to as “second fulcrum F2”) of the subframe 22 and immediately before the weld nut 33. A downward force acts on the action point S1 of the part. That is, in the middle of the input of the collision load, the support wall 10a portion of the front end extending member 10 becomes the second fulcrum F2, and a force for pulling out the fastening bolt 31 with a large stroke is applied.

Next, the operation of the above embodiment will be described.
When a collision load in the front-rear direction of the vehicle body is input to the front portion of the front side frame 11, the collision load is partially distributed to the subframe 22 and transmitted to the frame member below the passenger compartment. At this time, the front side frame 11 is gradually crushed in the front-rear direction as the collision progresses, the subframe 22 bends downward at the central folding point 27 portion, and finally the subframe main body 23 is in the compartment I. It turns downward and the rear end of the sub-frame body 23 falls off the vehicle body.

Hereinafter, the behavior of the subframe 22 at this time will be described in detail.
In the initial stage of input of the collision load, when the subframe 22 is bent downward at the central folding point 27, as shown in FIG. 20, the first fulcrum F1 of the lateral member 20 becomes a mechanical fulcrum, and the force in the pulling direction Acts on the fastening bolt 31 and the weld nut 33. At this time, a large force acts on the fastening bolt 31 and the weld nut 33 although the stroke is small.
When the subframe 22 begins to bend downward at the center folding point 27, the extension piece 29 of the rear fastening portion 22u comes into contact with the support wall 10a of the front end extension member 10 as shown in FIG. It moves from the first fulcrum F1 to the second fulcrum F2 on the support wall 10a. Thereby, a load acts on the fastening bolt 31 and the weld nut 33 downward with a large stroke.
When the mechanical fulcrum moves from the first fulcrum F1 to the second fulcrum F2 on the support wall 10a, the link stay 30 integrated with the subframe main body 23 is slightly displaced together with the subframe main body 23 toward the rear side of the vehicle body. At this time, the support bolt 39 relatively displaces in the notch groove 30m (displacement allowable portion 60) on the rear side of the link stay 30.

On the other hand, when a downward force U (see also FIGS. 1 and 10) acts on the upper mounting arm 25 at this time, the two fixing bolts 48 that fix the upper mounting arm main body 47 and the connecting bracket 46 cause the notch 53 to be cut. Break. As a result, the upper mounting arm main body 47 falls off while leaving the connection bracket 46 on the front side frame 11 as shown in FIG. As a result, the subframe main body 23 is allowed to rotate about the first fulcrum F1 and the second fulcrum F2.
When the upper mounting arm main body 47 falls off in this way, a large downward force acts on the fastening bolt 31 and the weld nut 33 at the same time, whereby the fragile portion Z of the lateral member 20 starts to break.

When the collision load is further input, as shown in FIGS. 22 to 24, the fastening bolt 31 is pulled down together with the weld nut 33, and the subframe main body 23 rotates around the support bolt 39 through the link stay 30. To move.
At this time, when the subframe main body 23 rotates around the support bolt 39 by a predetermined angle, the front end side of the subframe main body 23 is grounded as shown in FIG.

In this state, the vehicle continues to move forward, and as shown in FIG. 23, the apex viewed from the side surface of the downward convex portion 30x of the link stay 30 is the center folding point 27 of the subframe 22 and the rear fastening portion 22u. In addition, a triangular truss structure is formed and positioned below a straight line L connecting the center break point 27 and the fastening center O at the rear end of the link stay 30 (the positional relationship of FIG. 1 is maintained). Since the link stay 30 is provided with a rigid recess 30h on the front side, the truss structure described above has an end position on the rear side of the recess 30h of the link stay 30 (the downward convex portion 30x). It is extended to (position with).
For this reason, when the front end side of the subframe main body 23 is grounded and the vehicle advances as it is, when the distance between the center folding point 27 and the fastening center O at the rear end of the link stay 30 is to be shortened, the link stay 30 The force concentrates on the downward convex portion 30x. As a result, as shown in FIG. 24, the link stay 30 is bent downward about the lower convex portion 30x.

Therefore, when the collision further proceeds thereafter, the link stay 30 rotates at two points of the fastening center O of the support bolt 39 and the downward convex portion 30x as shown in FIG. The subframe main body 23 is guided to the lower side of the passenger compartment by turning.
Then, when the second half of the link stay 30 is pivoted about the fastening center O until it is substantially directed in the vertical direction, the link stay 30 falls down from the support bolt 39 along the notch groove 30m at the rear end. As a result, the rear part of the subframe main body 23 is finally dropped on the lower side of the passenger compartment I.

As described above, in this vehicle body frame structure, when a collision load in the vehicle longitudinal direction is input, the subframe 22 bends downward at the central folding point 27, and the rear fastening portion 22 u of the subframe body 23 is connected to the link stay 30. Since the rear end of the sub-frame main body 23 is rotated around the axis of the support bolt 39 together with the link stay 30 together with the sub-frame 22. The suspension parts to be driven can be reliably guided below the passenger compartment.
The vehicle body frame structure can reliably guide the subframe 22 and the suspension parts below the passenger compartment I as described above when a collision load in the longitudinal direction of the vehicle body is input, but uses a complicated mechanism. Therefore, an increase in the weight of the vehicle and an increase in product cost can be suppressed.

  Further, in this vehicle body frame structure, a nut 38 for fastening the rear end portion of the link stay 30 to the front end extending member 10 is held on the side wall 30so on the outer side in the vehicle width direction of the link stay 30, and the support bolt 39 is fixed to the floor. Since the nut 38 is tightened from the lower side of the tunnel portion 18, the fastening operation of the support bolt 39 can be easily performed in a wide space below the floor tunnel portion 18 when the vehicle body is assembled. Therefore, by adopting this structure, the assembly workability of the vehicle body can be improved.

  Further, in this vehicle body frame structure, the nut 38 for fastening the rear end portion of the link stay 30 to the front end extending member 10 is integrally assembled to the nut cover 65 having the engaging claws 65c, so that the link is previously provided. By engaging the engaging claw 65c and the engaging protrusion 65d of the nut cover 65 with the engaging hole 66 and the notch groove 30m on the side wall 30so of the stay 30, the support bolt is positioned without positioning the nut 38 again. 39 can be easily fastened.

  In the case of this embodiment, on the side of the nut 38 that is assembled integrally with the nut cover 65, a restriction projection 67 that is fitted in the notch groove 30m on the side wall 30so and restricts the rotation of the nut 38 is provided. Therefore, the support bolt 39 can be securely fastened to the nut 38 without the operator pressing the nut 38 portion with a jig or the like.

  In particular, in the vehicle body frame structure of this embodiment, the front end extending member 10 is attached to a position of the lower surface of the dash lower panel 17 and the floor panel 19 that approaches the floor lower side surface 55b of the stepped portion 55. The nut 38 must be arranged in a narrow portion between the side wall 30so on the outer side in the vehicle width direction of the link stay 30 and the floor lower side surface 55b, but the nut 38 is previously attached to the side wall 30so together with the nut cover 65 as described above. In addition, since the support bolt 39 can be fastened without the operator pressing the nut 38, the assembly work of the vehicle body can be performed easily and efficiently.

  Further, in this embodiment, a notch groove 30m is provided in the rear end portion of the side walls 30so, 30si of the link stay 30, and a support bolt 39 for fastening the rear end portion of the link stay 30 to the front end extending member 10 is provided. Since it is inserted into the notch groove 30m, the link stay 30 is notched when the latter half of the link stay 30 is largely rotated around the support bolt 39 in the latter half of the input of the collision load in the longitudinal direction of the vehicle body. It can be reliably dropped down along 30 m. Accordingly, the rear end portion of the sub-frame 22 is finally dropped below the passenger compartment I, and the interference between the suspension component mounted on the sub-frame 22 and the passenger compartment front can be avoided.

  Further, in the case of this embodiment, in a state where the rear end portion of the link stay 30 is fastened to the front end extending member 10 by the support bolt 39, the displacement allowance portion 60 is secured between the bottom portion of the notch groove 30 m and the support bolt 39. Therefore, when the link stay 30 is about to be slightly displaced rearward together with the subframe body 23 in the middle stage of input of the collision load in the longitudinal direction of the vehicle body, the relative displacement of the link stay 30 with respect to the support bolt 39 is changed. 60, and it is possible to prevent unnecessary deformation of the link stay 30. Therefore, after that, the link stay 30 can be reliably folded at a predetermined position, and finally the subframe 22 can be reliably guided below the passenger compartment I.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment, the vehicle body frame structure according to the present invention is applied to the front side of the vehicle. However, if the vehicle has a side frame and a subframe on the rear side of the passenger compartment, the present invention is applied to the present invention. Such a body frame structure can also be applied to the rear side of the vehicle.

10 Front end extension member (frame under the floor)
10a Support wall 11 Front side frame (side frame)
15 Floor tunnel frame (under-floor frame)
17 Dash lower panel 18 Floor tunnel part 19 Floor panel 20 Lateral member (support member substrate, passenger compartment side support member)
22 Subframe 22m Front fastening part (separation side fastening part)
22u Rear fastening part (proximity side fastening part)
27 Folding point 30 Link stay 30m Notch groove (bolt insertion part)
30 so .. side wall on the side to be separated 35 Reinforcement plate (vehicle compartment side support member)
38 Nut 39 Support Bolt 60 Displacement Allowable Part 65 Nut Cover 65c Engaging Claw 67 Restriction Projection

Claims (5)

A side frame disposed along the front-rear direction of the vehicle body on the front side or rear side of the passenger compartment;
A subframe disposed below the side frame and supporting suspension parts;
A vehicle compartment side support member that is disposed on the outside lower side of the front portion or the rear portion of the vehicle compartment and supports an end portion of the subframe adjacent to the vehicle compartment;
A lower floor frame arranged along the longitudinal direction of the vehicle body below the stepped portion of the floor adjacent to the floor tunnel portion of the passenger compartment;
A link stay arranged across the end of the subframe close to the passenger compartment and the lower floor frame, and connecting the two;
The sub-frame includes a separation-side fastening portion that is fastened to a member on the extension end side of the side frame at an end portion on the side away from the vehicle compartment, and the vehicle compartment side support at an end portion on the side close to the vehicle compartment. A proximity-side fastening portion fastened and fixed to the member from the lower side, and a central folding point that is bent downward at a substantially central portion in the front-rear direction between the separation-side fastening portion and the proximity-side fastening portion,
The link stay is fastened to the lower surface of the passenger compartment side support member together with the proximity side fastening portion so that the link stay can be pulled out, and the other end side is attached to the support bolt and the support bolt extending in the vehicle width direction. Fastened to the lower floor frame by a screwed nut,
The nut for fastening the other end of the link stay is held on the side wall of the link stay on the side away from the floor tunnel,
The vehicle body frame structure according to claim 1, wherein the support bolt is fastened to the nut from a lower side of the floor tunnel portion.   The vehicle body frame structure according to claim 1, wherein the nut is integrally assembled to a nut cover having an engaging claw locked to a side wall of the link stay. The side wall of the link stay is provided with a bolt insertion part through which the support bolt is inserted,
3. The vehicle body frame structure according to claim 1, wherein the nut includes a restricting protrusion that is locked to the bolt insertion portion on the side wall of the link stay and restricts rotation. 4. The side wall of the link stay is provided with a bolt insertion part through which the support bolt is inserted,
The bolt insertion portion is provided with a displacement allowance portion that allows relative displacement of the link stay and the support bolt accompanying displacement of the subframe in the longitudinal direction of the vehicle body when a collision load in the longitudinal direction of the vehicle body is input. The vehicle body frame structure according to any one of claims 1 to 3. The side wall of the link stay is provided with a bolt insertion part through which the support bolt is inserted,
The bolt insertion part is configured by a notch groove that allows the link stay to be detached from the support bolt accompanying a downward displacement of the subframe when a collision load in the longitudinal direction of the vehicle body is input. The body frame structure according to any one of claims 1 to 4.

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