JP4867509B2 - Subframe structure - Google Patents

Description

  The present invention relates to a subframe structure that is disposed below a vehicle body side frame portion that extends in the vehicle front-rear direction at the front or rear portion of a vehicle, and relates to a subframe structure characterized by a deformation mode at the time of a vehicle collision.

As a conventional subframe structure, for example, there is a structure described in Patent Document 1. In this conventional structure, the sub-frame is disposed at a position below the vehicle body side frame that extends in the vehicle longitudinal direction on both sides in the vehicle width direction and absorbs energy by axial crushing against an impact load in the vehicle longitudinal direction. . The sub-frame is provided with a deformation starting point portion that bends and deforms downward due to the collision load. The lower part of the power unit is supported at or near the deformation starting point of the subframe, and the upper part of the power unit is rotatably supported by a reinforcing part provided at the base of the vehicle body side frame. And the setting of the said deformation | transformation origin part is set by attaching the bending angle | corner below to the longitudinal direction middle part of a sub-frame.
JP 2002-192958 (FIG. 2 and others)

However, when the sub-frame is constituted by a hollow member, even if the deformation starting point portion is provided as described above, the sub member is a hollow member at a position different from the deformation starting point portion when the collision load is input. It has been found by the inventor's earnest study that the frame may undergo cross-sectional deformation (compression or folding) and may not be in the assumed downward deformation mode.
The present invention has been made paying attention to the above points, and even if the subframe is constituted by a hollow member, the subframe is in a downward deformation mode at an assumed position at the time of a collision from the vehicle longitudinal direction. The challenge is to provide a structure.

In order to solve the above problems, the present invention is a subframe structure that is disposed below a vehicle body side frame that extends in the vehicle longitudinal direction and is connected to the vehicle body side frame,
A sub-frame body having a hollow cross section extending in the vehicle front-rear direction, a front connection member and a rear connection member for connecting the front and rear portions of the sub-frame body to the vehicle body side frame, and the vehicle front-rear side above the sub-frame body One or more first reinforcing members extending in the direction,
The first reinforcing member has one end fixed to the front connecting member or the rear connecting member, and the other end positioned on the subframe main body at a midpoint in the longitudinal direction of the subframe main body. abut, the first reinforcing member is set to a position towards the other end is lower than the one end portion,
A second reinforcing member is provided in the hollow portion of the subframe main body, and the second reinforcing member has an overlapping portion that overlaps with the other end side of the first reinforcing member in a top view. is there.

  According to the present invention, even if the subframe body is a hollow member, the subframe body can be deformed downward at an assumed position by an impact load in the vehicle longitudinal direction.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing a subframe of this embodiment, and FIG. 2 is a side view thereof.
In the present embodiment, a front suspension member disposed in the front portion of the vehicle will be described as an example of the subframe. Of course, it may be a suspension member at the rear of the vehicle, or may be applied to other subframes.

(Constitution)
As shown in FIG. 2, the sub frame is disposed below the vehicle body side frame 2 extending in the vehicle front-rear direction, and is connected to the vehicle body side frame 2.
As shown in FIGS. 1 and 2, the basic structure of the subframe 1 includes left and right side members 3 extending in the vehicle longitudinal direction in the vehicle width direction, and the front and rear end portions of the left and right side members 3. The cross members 4 are arranged in front of and behind in the vehicle width direction so as to connect each other, and this structure forms a cross-girder structure in a plan view and ensures a predetermined high rigidity. Here, the side member 3 constitutes a subframe main body.

  The side member 3 is composed of an upper plate 5 and a lower plate 6 as shown in FIG. The upper plate 5 is constituted by a top plate portion 5a and left and right side plate portions 5b extending continuously downward on both sides in the vehicle width direction of the top plate portion 5a, so that a U-shaped cross section opened downward. This is a plate member. By closing the lower opening end of the upper plate 5 with the lower plate 6, the side member 3 has a closed cross section and has a hollow portion extending in the vehicle front-rear direction inside.

  Further, the front end portion and the rear end portion of the left and right side members 3 are elastically supported by the vehicle body side frame 2 via front insulators 7 and 8 whose axes are directed upward and downward, respectively. It is linked to. In each of the front insulators 7 and 8, outer cylinders 7a and 8a and inner cylinders 7b and 8b whose axes are directed vertically are arranged in a nested manner, and the outer cylinders 7a and 8a and the inner cylinders 7b and 8b are elastic. Further, the positions of the upper end surfaces of the inner cylinders 7b and 8b are located higher than the positions of the upper end surfaces of the outer cylinders 7a and 8a. The front end or rear end of the side member 3 is integrally fixed to the outer diameter surface of each outer cylinder 7a, 8a, and the inner cylinder 7b, The upper end portion of 8b is fixed to the vehicle body side frame 2 by fastening.

In this embodiment, the elastic bodies 7c and 8c that are interposed between the outer cylinders 7a and 8a and the inner cylinders 7b and 8b and connect the two are mainly the outer cylinders as shown in FIGS. The elastic members of the front insulators 7 and 8 are positioned above the attachment point with the side member 3 and are disposed at positions above the front end or rear end attachment portion of the side member 3 to 7a and 8a.
Here, the front insulator 7 constitutes a front connecting member, and the rear insulator 8 constitutes a rear connecting member.

  A first reinforcing member 9 made of a plate member is disposed above the side member 3. The first reinforcing member 9 extends in the vehicle front-rear direction along the upper surface of the side member 3. The first reinforcing member 9 is a U-shaped member that opens downward, and includes a first reinforcing member main body 9a (top plate portion) disposed with a predetermined space above and below the side member 3, and It is comprised from the left-right side board part 9b extended continuously below the vehicle width direction edge part of the 1st reinforcement member main body 9a. The lower end portions of the left and right side plate portions 9b abut against the side member 3 and are fixed by welding or the like. Thus, the first reinforcing member 9 forms a closed cross section with the upper surface of the side frame 3 so as to form a cavity on the upper side of the side member 3.

The front end portion of the first reinforcing member 9 is integrally fixed to the outer diameter surface of the outer cylinder 7 a of the front insulator 7. This fixed position is preferably a lower position than the elastic center of the front insulator 7. Further, the rear end portion 9c of the first reinforcing member 9 is fixed in contact with the upper surface of the side member 3 at a position in the vehicle longitudinal direction of the side member 3.
Here, the front end portion of the first reinforcing member constitutes one end portion, and the rear end portion side constitutes the other end portion.

In the present embodiment, as shown in FIG. 2, the height of the front end portion of the first reinforcing member 9 is set to be higher than the height of the rear end portion of the first reinforcing member 9.
A third reinforcing member 10 made of a flat plate member is disposed along the lower surface of the top plate portion 5a of the side member 3 and is fixed to the top plate portion 5a.

  The rear end of the third reinforcing member 10 is integrally fixed to the outer cylinder 8a of the rear insulator 8 and extends forward in the vehicle front-rear direction. The fixed position is preferably a position below the elastic center of the rear insulator 8. The front end portion of the third reinforcing member 10 is fixed to the top plate portion 5 a of the side member 3 at a position rearward in the vehicle longitudinal direction from the rear end portion of the first reinforcing member 9. In the present embodiment, the case where the third reinforcing member 10 has a flat plate shape is described as an example, but a U-shaped member such as the first reinforcing member 9 may be used. Moreover, the direction which has the side-plate part extended up and down can set the bending rigidity of an up-down direction high, suppressing the increase in mass. The third reinforcing member 10 may be provided on the top surface of the top plate portion 5a of the side member 3. The rear end portion of the third reinforcing member 10 constitutes one end portion and the other end portion constitutes the other end portion.

Here, in the present embodiment, a bent deformation portion X is formed between the rear end position of the first reinforcing member 9 and the front end position of the third reinforcing member 10 in the vehicle longitudinal direction.
A flat plate-like second reinforcing member 11 extending in the vehicle front-rear direction is disposed in the hollow portion of the side member 3. As shown in FIG. 6, the second reinforcing member 11 is a plate member arranged with the width direction facing up and down, and of the left and right side plate portions 5 b constituting the side member 3, the side plate 5 b on the outer side in the vehicle width direction. It is arrange | positioned so that it may extend in parallel with 'and along the said side plate 5b'. That is, the 2nd reinforcement member 11 comprises the partition, and is arrange | positioned so that the inside of the side member 3 may be divided | segmented in a vehicle width direction.

The front end portion of the second reinforcing member 11 is disposed at a position overlapping the rear end portion side of the first reinforcing member 9 in a top view. The rear end portion of the second reinforcing member 11 is disposed at a position that does not overlap the front end portion side of the third reinforcing member 10 in a top view. You may arrange | position the rear-end part of the 2nd reinforcement member 11 in the position which overlaps with the front-end part of the 3rd reinforcement member 10 in top view.
The side plate portion 5b 'of the side member 3 facing the second reinforcing member 11 serves as a front vehicle body side mounting portion of a transverse link (suspension link), and the second reinforcing member 11 has its mounting portion. It is reinforced.

  In the present embodiment, through holes 5c and 11c that pass through the side plate portion 5b 'and the second reinforcing portion of the side member 3 coaxially are opened, and the side plate portion 5b' and the second plate 5b are coaxial with the through holes 5c and 11c. 2 A cylinder 15 (collar) is disposed between the reinforcing member 11 and connected to the side plate portion 5b ′ and the second reinforcing member 11 for further reinforcement. The nut 16 is fixed coaxially with the through hole by welding or the like. Reference numeral 17 denotes a nut pocket. The transverse link body is formed through two attachment bolts 18 which are formed at two places apart from each other in the longitudinal direction of the vehicle and are inserted into the two through holes and screwed into the nut 16. Bush members provided on the side portions are connected.

That is, as shown in FIG. 7, the transverse link 20 extends in the vehicle width direction, the wheel side end portion is connected to a knuckle (not shown) by the ball joint 21, and the vehicle body side end portion is in the vehicle longitudinal direction. It is attached to the side member 3 at two points apart. Of the two locations, the front mounting portion is constituted by a bush member 22 having an axis directed in the vehicle front-rear direction. The bush member 22 is configured by inserting an elastic body between an inner cylinder 22 b and an outer cylinder 22 a that are arranged coaxially, and the outer cylinder 22 a is fixed to the transverse link 20. The inner cylinder 22b has a length sufficient to project on both sides of the outer cylinder 22a. Bolt holes 23 facing the vehicle width direction are opened on both sides of the inner cylinder 22b projecting from the outer cylinder 22a. The above-described bolt 18 is inserted into the bolt hole 23 to be attached as described above. The inner cylinder 22b may be a solid rod.
In addition, the rear side attaching part 24 of the two places is configured by a bush member having an axis directed up and down, and is attached at a position indicated by reference numeral 25 in FIG.

(Action / Effect)
First, the effect of the 1st reinforcement member 9 is demonstrated with reference to FIG.
An input in the vehicle front-rear direction applied to the vehicle body side frame 2 at the time of a vehicle collision from the front of the vehicle is transmitted to the subframe 1 via the front insulator 7 and the rear insulator 8 and is used as a force for compressing the subframe 1 in the axial direction. At this time, since the front end portion of the first reinforcing member 9 is integrally fixed to the front insulator 7, the input applied to the vehicle body side frame 2 at the time of the vehicle collision is reliably transmitted to the first reinforcing member 9. It is the composition which becomes.

  Further, the input applied to the vehicle body side frame 2 at the time of the vehicle collision acts on the upper end portion of the inner cylinder 7b of the front insulator 7 as a force toward the rear in the vehicle front-rear direction, and the elastic center of the front insulator 7 or the vicinity thereof is the center. The front insulator 7 acts as a force that inclines so that the upper end portion is relatively displaced rearward in the vehicle front-rear direction, and the force is applied to the side member 3 and the first member that are integrally fixed to the front insulator 7 and the front end portion. 1 is transmitted to the reinforcing member 9. This force acts as a force that bends the side member 3 downward. Further, the force acting on the first reinforcing member 9 is concentrated on the rear end side of the first reinforcing member 9 and concentratedly applied to the top plate portion 5a portion of the side member 3 on the lower side.

Further, the side member 3 portion that overlaps the first reinforcing member 9 in plan view is reinforced by the first reinforcing member 9 and has high rigidity, so that an axial load is applied to the side member 3 at the time of a vehicle collision. However, compression deformation, bending deformation, and local cross-sectional deformation are suppressed, and the side member 3 is easily bent in the vicinity of the rear end portion of the first reinforcing member 9 or in the rear position thereof.
From the above, at the time of the vehicle collision, the side member 3 is surely bent downward from the vicinity of the rear end portion of the first reinforcing member 9 to the front end portion of the third reinforcing member 10 at the bending deformation portion X. become.

  Here, in this embodiment, since the cavity is formed between the top plate portion 5a of the side member 3 and the first reinforcing member 9, the section modulus with respect to the bending of the side member 3 portion overlapping the first reinforcing member 9 is determined. It is possible to increase the rigidity of the side member 3 at the portion overlapping the first reinforcing member 9 in a plan view more effectively without increasing the mass, and the position of the bending deformation portion X can be further increased. This makes it easier to bend down.

Furthermore, since the height of the rear end portion of the first reinforcing member 9 is designed to be lower than the height of the front end portion that is integrally fixed to the front insulator 7, the first reinforcing member 9 is connected to the first reinforcing member 9 from the front insulator 7. The load concentration toward the lower side at the rear end portion due to the input is further increased, and the downward force input to the side member 3 from the rear end portion of the first reinforcing member 9 can be further increased. The structure is easy to bend downward at the position X.
As described above, in the present embodiment, the deformation of the side member 3 at the time of the vehicle collision can be reliably deformed in the desired folding deformation portion X position at the desired folding position. As a result, a reaction force can be reliably generated at the time of a collision, that is, the collision energy can be efficiently absorbed by the deformation of the subframe 1, and the deformation of the passenger compartment can be suppressed.

Next, the function and effect of the third reinforcing member 10 will be described.
Input applied to the vehicle body side frame 2 at the time of a vehicle collision is transmitted to the side member 3 via the front insulator 7 and the rear insulator 8. At this time, since the rear end portion of the third reinforcing member 10 is integrally fixed to the rear insulator 8, the input applied to the vehicle body side frame 2 at the time of a vehicle collision is reliably transmitted to the third reinforcing member 10. It has a configuration. Since a reaction force is generated in the side member 3 reinforced by the third reinforcing member 10 with respect to the transmitted input, the side member 3 reinforced by at least the third reinforcing member 10 is also reliably deformed without local deformation. Reaction force can be generated. That is, since collision energy can be absorbed reliably, the amount of collision energy that can be absorbed by the subframe 1 can be increased, and deformation of the passenger compartment can be further suppressed.
In addition, as described above, there is also an effect that the portion that is bent and deformed can be reliably set to the front side in the vehicle front-rear direction with respect to the third reinforcing member 10.
In addition, by providing the third reinforcing member 10 with the side plate portion 5b extending vertically, the rigidity against bending in the vertical direction by the third reinforcing member 10 can be further increased.

Next, the effect of the 2nd reinforcement member 11 is demonstrated.
When the side member 3 receives a downward load from the rear end portion of the first reinforcing member 9 at the time of a vehicle collision and bends downward or tries to bend, the rear end portion of the first reinforcing member 9 is A reaction force is generated by coming into contact with the upper end portion of the second reinforcing member 11 through the top plate. As a result, even after the side member 3 is bent and deformed, a reaction force against the collision input can be generated. That is, since the collision energy can be continuously absorbed, the amount of the collision energy that can be absorbed by the subframe 1 can be increased, and the deformation of the passenger compartment can be further suppressed.

Further, a downward load is applied so that the rear end portion of the first reinforcing member 9 contacts the second reinforcing member 11 from above and is transmitted to the second reinforcing member 11. As a result that the side member 3 of the provided portion is less likely to be compressed and deformed by the second reinforcing member 11, the position where the side member 3 is bent downward moves rearward in the vehicle front-rear direction compared to the case where the second reinforcing member 11 is not provided.
Here, if the second reinforcing member 11 is not provided, the side member 3 is locally deformed in the cross section at the position corresponding to the bending deformation portion X due to the bending deformation of the side member 3, and the reaction force is reduced. Occurrence may be reduced.

  Further, since the front attachment portion of the transverse link is set at a position overlapping the second reinforcement member 11 in the vehicle width direction, the second reinforcement member 11 also serves as reinforcement of the suspension link attachment portion. That is, the second reinforcing member 11 can increase the rigidity of the front mounting portion. In particular, in the present embodiment, by connecting a mounting bolt for mounting to the second reinforcing member 11 as well, the rigidity can be set higher, and the number of parts of the suspension link mounting portion requiring high mounting rigidity can be reduced. It becomes possible to do.

  Here, in this embodiment, the side member 3 extends in the vehicle front-rear direction, but as shown in FIG. 1, the rear end side is designed to be inclined slightly inward in the vehicle width direction, and the vehicle width is larger than the inclination direction. Since the rear insulator 8 is set on the outer side in the direction, when a compressive load in the axial direction is applied to the side member 3 at the time of the vehicle collision, the front side in the vehicle front-rear direction with respect to the rear insulator 8 is provided. A load is also applied to the vicinity of the connecting portion between the side member 3 and the rear cross member 4. In order to cope with this, a fourth front side in the vehicle front-rear direction from the rear insulator 8 and in the vicinity of the connecting portion between the side member 3 and the rear cross member is directed in the vehicle width direction. A partition wall portion 30 that is a reinforcing member is provided, and by reinforcing the partition wall member 30, when the collision load is input to the subframe 1, it is possible to prevent compressive deformation near the connection portion. Yes.

Next, reaction forces generated in the subframe 1 for absorbing the collision energy by the first reinforcing member 9, the second reinforcing member 11, and the third reinforcing member 10 will be described collectively in time series. FIG. 9 is a schematic diagram of a time chart of reaction force generation at that time.
First, when a collision load due to a collision from the front of the vehicle is applied, first, a load compressed in the axial direction by the input at the time of the collision acts, so that the entire cross beam-like subframe 1 instantaneously generates a repulsive force. Thus, the maximum reaction force is generated (STEP 1).

Subsequently, the side member 3 is deformed into a V shape by using the position of the bending deformation portion X between the first reinforcing member 9 and the third reinforcing member 10 as a trigger for the deformation (STEP 2).
After the V-shaped deformation, the second reinforcing member 11 is stretched to maintain the average reaction force and absorb the collision energy (STEP 3).
Here, in the said embodiment, although the case where the width | variety by the side of the rear-end part of a 1st reinforcement member becomes narrow is illustrated, the width | variety of a rear-end part does not need to be narrow.

In the above embodiment, the upper end portion of the second reinforcing member 11 is in contact with the top plate portion 5 a of the upper plate of the side member 3, but the portion overlapping the first reinforcing member 9 in the vertical direction is the top of the side member 3. An upper and lower gap may be provided without contacting the plate portion 5a. When the gap is provided in this way, when the rear end portion side of the first reinforcing member 9 abuts against the top plate portion 5a of the side member 3 and a load is applied downward, the side member 3 is bent as much as the gap is eliminated. After the occurrence, the rear end side of the first reinforcing member 9 comes into contact with the second reinforcing member 11 via the side member 3, so that the first reinforcing member can be bent more reliably.
Moreover, although the said embodiment illustrated the submember 1 arrange | positioned at the vehicle front part, in the case of the submember arrange | positioned at the vehicle rear part, the arrangement | positioning of the front and back of a reinforcement member is reversed and it is set as a rear insulator. The rear end portion of the first reinforcing member is fixed, and the front end portion of the third reinforcing member is fixed to the front insulator.

It is a top view which shows the submember based on Embodiment based on this invention. It is a side view which shows the side member which concerns on embodiment based on this invention. It is sectional drawing which shows the relationship between the side member which concerns on embodiment based on this invention, and a 1st reinforcement member. It is sectional drawing which shows the front side insulator vicinity. It is sectional drawing which shows the rear side insulator vicinity. It is AA sectional drawing in FIG. It is a top view which shows a transverse link. It is a schematic diagram which shows the example of arrangement | positioning of each reinforcement member. It is a time chart of reaction force generation.

Explanation of symbols

1 Subframe 2 Car body side member 3 Side member (submember body)
5 Upper plate 5a Top plate portion 5b Side plate portion 5c Through hole 6 Lower plate 7 Front insulator (front connection member)
8 Rear insulator (rear connecting member)
9 First reinforcing member 9a Top plate portion 9b Side plate portion 10 Third reinforcing member 11 Second reinforcing member 11c Through hole 16 Nut 18 Mounting bolt 20 Transverse link 22 Bush member 22b Inner cylinder 23 Hole 30 Bulkhead

Claims (6)

A sub-frame structure disposed below the vehicle body side frame extending in the vehicle longitudinal direction and connected to the vehicle body side frame,
A sub-frame body having a hollow cross section extending in the vehicle front-rear direction, a front connection member and a rear connection member for connecting the front and rear portions of the sub-frame body to the vehicle body side frame, and the vehicle front-rear side above the sub-frame body One or more first reinforcing members extending in the direction,
The first reinforcing member has one end fixed to the front connecting member or the rear connecting member, and the other end positioned on the subframe main body at a midpoint in the longitudinal direction of the subframe main body. abut,
The first reinforcing member is set at a lower position on the other end side than on one end,
A second reinforcing member is provided in a hollow portion of the subframe main body, and the second reinforcing member has an overlapping portion that overlaps the other end side of the first reinforcing member in a top view. Construction.   2. The subframe structure according to claim 1, wherein the first reinforcing member forms a closed cross section with an upper surface of the subframe body so as to form a cavity on the upper side of the subframe body. 3. The subframe structure according to claim 1, wherein the upper portion of the second reinforcing member has a gap between the upper and lower surfaces of the subframe body at the position of the overlapping portion. . The first reinforcing member is fixed to one of the front side connecting member or the rear side connecting member, and one end is fixed to the other of the front side connecting member or the rear side connecting member, and in the vehicle longitudinal direction. The third reinforcing member is provided, and the other end of the third reinforcing member is fixed to the subframe main body at a position not overlapping the first reinforcing member in a top view. The subframe structure according to claim 3 . It said one end of the first reinforcing member, the sub-frame structure as claimed in any one of claims 1 to 4, characterized in that the front end portion fixed to the front connecting member. In the subframe structure in which the suspension link is attached to the subframe body,
The subframe structure according to any one of claims 1 to 5 , wherein the second reinforcing member is disposed at a position where the attachment portion of the suspension link can be reinforced.

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