JP5915237B2 - Subframe structure of automobile - Google Patents

Description

  The present invention relates to a sub-frame structure for an automobile, and more particularly to a sub-frame structure that is installed on the lower side of left and right side frames provided at the front or rear of a vehicle body and supports upper and lower arms of a suspension.

  2. Description of the Related Art Conventionally, a subframe that supports a suspension arm is known in which a support portion that supports an upper arm and a support portion that supports a lower arm are disposed at substantially the same position in the front-rear direction (Patent Document 1 below). 2).

  Among these, in Patent Document 1 below, a sub-direction is defined by a pair of left and right front-rear members (side member portions) extending in the front-rear direction and a vehicle width direction member (cross member portion) installed between the pair of left and right front-rear members. Constructs a frame. The upper arm support portion and the lower arm support portion are disposed at substantially the same position in the front-rear direction, and are integrally formed at both ends in the vehicle width direction of the vehicle width direction member.

  Further, in Patent Document 2 below, a subframe is configured by a pair of left and right front and rear members (side member portions) extending in the front and rear direction and a lateral member (cross member portion) constructed between the pair of left and right front and rear members. Yes. The mounting portion (bracket) having the upper arm support portion and the mounting portion (bracket) having the lower arm support portion are disposed on the upper and lower surfaces of the horizontal member, and both the mounting portions are disposed at substantially the same position in the front-rear direction. ing.

JP 2011-207351 A JP 7-32831 A

  In Patent Document 1, the vehicle width direction member having the upper arm support portion and the lower arm support portion has a hollow structure made up of a plurality of panel members, so that the support portion falls back and forth due to a load input from the upper arm and the lower arm. Reinforcing members (specifically, connecting members and connecting brackets) for prevention are necessary. For this reason, the conventional structure disclosed in Patent Document 1 has room for further improvement in terms of light weight and rigidity and the number of parts.

  Furthermore, the above-mentioned Patent Document 1 has an advantage that the vehicle width direction member has a hollow structure, which has an advantage of good productivity, but has a problem of causing vibration and noise in the vehicle due to surface vibration.

  Moreover, in the said patent document 2, when the load from an upper arm and a lower arm is input only to the upper and lower surfaces of a horizontal member via an attachment part, it will be easy to carry out a cross-sectional deformation (surface vibration) of the upper and lower surfaces minutely. As a result, the conventional structure disclosed in Patent Document 2 is disadvantageous in terms of rigidity and has the problem of causing vibration and noise in the vehicle due to surface vibration, as in Patent Document 1. .

  Therefore, the present invention includes a left and right side member portion formed in a pipe shape extending in the front-rear direction on the subframe, a cross member portion laid between the left and right side member portions, and the side member portion. An upper arm support bracket and a lower arm support bracket each having a pair of front and rear upper arm support portions, a lower arm support portion, and a lower arm support bracket projecting upwardly and downwardly and opening outward in the vehicle width direction. The support bracket is provided apart from each other, and has a pair of flange portions that extend in the front-rear direction from the upper arm support portion and the lower arm support portion, and are connected to the side member portion adjacent to each other in the vertical direction. The number of parts is automatic and vibration and noise can be suppressed. And to provide a sub-frame structure.

The sub-frame structure of the automobile according to the present invention is a sub-frame that is installed under the left and right side frames provided at the front part or rear part of the vehicle body and supports the upper and lower arms of the suspension. Left and right side member portions extending in the front-rear direction and formed in a pipe shape, a cross member portion laid between the left and right side member portions, and projecting upward and downward from the side member portions, respectively, The upper arm support bracket includes a pair of front and rear upper arm support portions, a hat-shaped upper arm support bracket having a lower arm support portion, and a lower arm support bracket. The lower arm support bracket is spaced downward from the upper arm support bracket. It provided the position, the front and rear from the upper arm support and the lower arm support portions Extend in direction, and has a pair of flanges connected to the side member section adjacent the top and bottom.

The above configuration has the following effects.
That is, weight reduction can be achieved by forming the side member portion in a pipe shape.
And, each flange part extending in the front-rear direction can set the connection length between the side member part and the upper and lower brackets (arm support part) longer, and when a load in the front-rear tilt direction is input from the upper and lower arms to the bracket In this case, the load in the front-rear direction can be canceled by applying a moment in the reverse direction between the vertically adjacent flange portions.
Thereby, even if the side member portion is formed in a pipe shape, it is possible to improve the rigidity with respect to the load in the forward / backward direction without providing a reinforcing member, and to suppress deformation of the side member portion and surface vibration, Vibration and noise in the side member portion can be suppressed.
In short, it is lightweight and rigid, has a small number of parts, and can suppress vibration and noise.

In one embodiment of the present invention, the lower arm support bracket is connected to the cross member portion, and a lower end portion of a flange portion of the upper arm support bracket is positioned below a vertical center portion of a side surface of the side member portion. It is connected with.
According to the above configuration, by connecting the lower arm support bracket to the cross member portion, the rigidity in the vehicle width direction of the lower arm support bracket can be secured, and the connection length between the upper arm support bracket and the side member portion is By securing the upper arm support bracket main body (front wall and rear wall) and the flange portion for a long time, it is possible to ensure the connection rigidity between them.

In one embodiment of the present invention, the upper arm support bracket is connected to the cross member portion in a range shorter than the lower arm support bracket in the vehicle width direction, and is connected to the side member portion rather than the lower arm support bracket. The spacing in the vertical direction from the arm to the arm support is small.
According to the above configuration, the rigidity of the lower arm support bracket can be ensured by setting the coupling length between the lower arm support bracket and the cross member portion to which a greater lateral force is applied than the upper arm support bracket, and the upper arm can be secured. The rigidity of the upper arm support bracket can be ensured by connecting the support bracket and the cross member portion.
Furthermore, since the connection position of the bracket with respect to the cross member portion differs in the vehicle width direction, stress concentration at the cross member portion can be prevented.

In one embodiment of the present invention, the cross member portion has a vehicle width direction side portion inclined inward in the vehicle width direction with respect to the center portion, and the flange portion of the upper arm support bracket is the same as the cross member portion. It is inclined in the direction.
According to the above configuration, when a load in the vehicle width direction is transmitted from the upper arm to the cross member portion, the load can be transmitted substantially linearly in the outer shell of the side member portion. Thereby, a deformation | transformation of a side member part can be suppressed, As a result, the surface vibration, noise, and rigidity fall resulting from a deformation | transformation of a side member part can be suppressed.

  According to the present invention, the left and right side member portions formed in a pipe shape extending in the front-rear direction on the subframe, the cross member portion laid between the left and right side member portions, and the side member portion A pair of front and rear upper arm support portions, a hat-shaped upper arm support bracket having a lower arm support portion, and a lower arm support bracket. The lower arm support bracket is provided so as to be spaced apart from each other, extends in the front-rear direction from the upper arm support portion and the lower arm support portion, and has a pair of flange portions connected to the side member portion adjacent to each other in the vertical direction. High rigidity, few parts, and vibration and noise suppression There is.

Bottom view showing the sub-frame structure of the automobile of the present invention Bottom view of the rear subframe and suspension arm removed from FIG. AA arrow sectional view of FIG. Rear sub-frame perspective view A perspective view showing the rear subframe as viewed from below Top view of the rear subframe Front view of rear subframe Rear view of rear subframe Side view of rear subframe BB sectional view of FIG. Bottom view schematically showing the subframe structure of an automobile Explanatory diagram when inputting in-phase lateral force Explanatory drawing at the time of input of different phase lateral force It is explanatory drawing of the geometry change at the time of lateral force input, Comprising: (a) Top view, (b) The front which shows the positional relationship of a front side vehicle body attachment part, a rear side vehicle body attachment part, a lower arm support part, and a rear lower arm support part Figure Explanatory drawing when inputting load in the forward / backward direction The top view which shows the other Example of the sub-frame structure of a motor vehicle CC sectional view taken along the line CC in FIG. Side sectional view showing still another embodiment of the sub-frame structure of an automobile Side sectional view showing still another embodiment of the sub-frame structure of an automobile Side sectional view showing still another embodiment of the sub-frame structure of an automobile

Lightweight and rigid, has a small number of parts, and has the purpose of suppressing vibration and noise. The sub is installed under the left and right side frames provided at the front or rear of the vehicle body and supports the upper and lower arms of the suspension. In the frame, the sub-frame includes left and right side member portions formed in a pipe shape extending in the front-rear direction, a cross member portion laid between the left and right side member portions, and an upper side from the side member portion and each projecting downwardly, said while opening outward in the vehicle width direction, a pair of upper arm supporting part longitudinal cross section a hat-shaped upper arm supporting bracket having a lower arm support portion comprises a lower arm support bracket, the lower arm support bracket provided from upper arm supporting bracket at a position spaced downwardly, the upper arm supporting section Extending in the longitudinal direction from the lower arm support portions and was realized by constituting that a pair of flange portions that are connected to the side member section adjacent the top and bottom.

An embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a bottom view showing a subframe structure of an automobile, FIG. 2 is a bottom view showing a state in which a rear subframe and a suspension arm are removed from FIG. 1, and FIG. 3 is a sectional view taken along line AA in FIG. .

<Description of body structure>
2 and 3, a rear floor 4 (floor panel) is connected to the rear portion of the center floor panel 1 through a rear seat pan 2 and a slant portion 3 that inclines in a front, rear, and rear height and extends rearward. doing.
The above-described center floor panel 1 and the front floor panel (not shown) are integrally or integrally formed with a tunnel portion 5 that protrudes into the vehicle interior at the center in the vehicle width direction and extends in the front-rear direction of the vehicle. Side sills 6 are joined and fixed to both ends of the front floor panel in the vehicle width direction.

The side sill 6 is a vehicle body strength member having a side sill closed cross section extending in the longitudinal direction of the vehicle by joining and fixing the side sill inner and the side sill outer, and a side sill reinforcement is provided in the side sill closed cross section as necessary. Provided.
A rear side frame 7 extending in the front-rear direction of the vehicle is provided from the rear seat pan 2 to the slant portion 3 and the rear floor 4.

The rear side frames 7 are respectively provided on the left side and the right side of the vehicle on the inner side in the vehicle width direction of the wheel house 8, and the rear side frames 7 are located on the upper surface side of the rear seat pan 2, the slant portion 3 and the rear floor 4. The rear side frame upper 7U, the rear seat pan 2, the slant portion 3, and the rear side frame lower 7L positioned on the lower surface side of the rear floor 4 are provided. These upper and lower rear side frame upper 7U and rear side frame lower 7L , 3 and 4, a rear side closed cross section extending in the longitudinal direction of the vehicle is formed.
The rear side frame 7 described above is a vehicle body strength member, and the front portion of the rear side frame 7 is connected to a side sill 6 at a kick-up portion (corresponding to a portion where a cross member 9 described later is disposed). Correspondingly, a cross member 9 (so-called No. 3 cross member) extending in the vehicle width direction is stretched between the front portions of the left and right rear side frames 7 and 7, and between the cross member 9 and the vehicle body floor panel. Has a closed cross section extending in the vehicle width direction.
Further, a vehicle body cross member 10 (so-called No. 4 cross member) is provided between the left and right rear side frames 7 and 7 at the front and rear intermediate portion of the rear side frame 7 corresponding to the rear portion of the slant portion 3 described above. Yes.

The vehicle body cross member 10 is positioned on the upper surface side of the slant portion 3 and connects the left and right rear side frame uppers 7U and 7U in the vehicle width direction, and is positioned on the lower surface side of the slant portion 3 Vehicle body cross member lower 10L for connecting the rear side frame lowers 7L, 7L in the vehicle width direction, and a closed cross section 11 extending in the vehicle width direction is formed between the vehicle body cross member upper 10U and the slant portion 3. The closed cross section 12 extending in the vehicle width direction is also formed between the vehicle body cross member lower 10L and the slant portion 3.
That is, the upper and lower closed sections 11 and 12 are formed so as to overlap in the vertical direction as shown in FIG. Further, an attachment point 10P of a front vehicle body attachment portion 25 (see FIG. 1) of a subframe 21 described later is provided on the inner side in the vehicle width direction of the vehicle body cross member lower 10L than the rear side frame 7.
As shown in FIG. 2, a fuel tank 14 as a vehicle auxiliary machine is disposed in front of the subframe 21 in the vehicle, and the fuel tank 14 uses the pair of tank bands 13 and 13 as described above. The pan 2 and the slant portion 3 are attached to the outside of the lower vehicle.

On the other hand, as shown in FIG. 2, crash cans 15 and 15 as impact energy absorbing members are attached to the rear ends of the pair of left and right rear side frames 7 and 7, and between the left and right crash cans 15 and 15. A bumper reinforcement 16 is horizontally mounted so as to extend in the vehicle width direction.
Further, as shown in FIG. 2, a trailing arm vehicle body mounting portion 17 is formed in the above-mentioned rear side frame lower 7 </ b> L so as to correspond to the front and rear cross members 9, 10, and is located further rearward than the vehicle body cross member 10. The rear side frame lower 7L is provided with a spring seat 18 of a suspension spring 27 (see FIG. 1), which will be described later, and the rear side frame lower 7L corresponds to a rear position further than the spring seat 18. Is provided with an attachment point 19 for the rear vehicle body attachment portion 26 (see FIG. 1).
Further, as shown in FIG. 2, a rear suspension damper vehicle body mounting portion 20 is provided in the wheel house 8.

<Description of subframe>
2 and 3, a rear subframe 21 (hereinafter simply abbreviated as a subframe) is attached as shown in a bottom view of FIG. 7 and 7, the subframe 21 is installed on the lower side.

4 is a perspective view showing the subframe 21 as seen from above, FIG. 5 is a perspective view showing the subframe 21 as seen from below, FIG. 6 is a plan view of the subframe 21, and FIG. FIG. 8 is a rear view of the subframe 21, and FIG. 9 is a side view of the subframe 21.
As shown in FIGS. 4 to 9, the sub-frame 21 that supports the rear suspension includes left and right side member portions 22, 22, a front cross member portion 23 laid between the side member portions 22, 22, and a rear The side cross member part 24 is provided, and it is formed in left-right substantially symmetrical (refer FIG. 6) by planar view.

The pair of left and right side member portions 22, 22 extend in the front-rear direction and are formed in a pipe shape, that is, formed by a pipe member. The front mounting portion) and the rear vehicle body mounting portion 26 (so-called rear mounting portion) are provided at the same height position (see FIG. 3).
The front vehicle body mounting portion 25 is disposed on the inner side in the vehicle width direction with respect to the rear vehicle body mounting portion 26, whereby a virtual line L0 (see FIGS. 6 to 8) passing through both the vehicle body mounting portions 25 and 26 is obtained. Inclined inward in the vehicle width direction.
As shown in FIG. 1, the rear portions of the left and right side member portions 22, 22 are respectively connected to the left and right rear side frames 7 (specifically, attachment points 19 of the rear side frame lower 7 </ b> L) via the rear body mounting portions 26, 26. ), The front portions of the left and right side member portions 22 and 22 are located on the inner side in the vehicle width direction than the rear side frame 7 of the vehicle body cross member 10 (No. 4 cross member) via the front vehicle body mounting portions 25 and 25. Installed on. Specifically, the front vehicle body attachment portions 25, 25 are attached to an attachment point 10P (see FIG. 2) of the vehicle body cross member lower 10L.
That is, the side member portion 22 is attached to the vehicle body at two locations, the front vehicle body attachment portion 25 and the rear vehicle body attachment portion 26.

Accordingly, the rear impact load received by the rear portion of the rear side frame 7 is transmitted to the vehicle body cross member 10 via the side member portion 22, and the load is distributed from the vehicle body cross member 10 to members such as a floor panel other than the rear side frame 7. Thus, the rear impact load is distributed to prevent the subframe 21 from moving forward and deformation of the vehicle body located in front of the sub frame 21, thereby improving the rear impact safety.
Further, as shown in FIG. 1, each of the side member portions 22, 22 described above is provided from the rear vehicle body mounting portion 26 of the subframe 21 so that a suspension spring 27 (coil spring) can be disposed in front of the side member portion 22, 22. It extends inward in the vehicle width direction, and is thereby configured to achieve both the dispersion of the rear impact load and the layout of the suspension spring 27.
More specifically, the rear vehicle body mounting portion 26 is disposed behind the suspension spring 27, and the rear portion of the side member portion 22 extends from the rear vehicle body mounting portion 26 inward in the vehicle width direction while the front portion. However, it extends substantially linearly toward the front vehicle body mounting portion 25.

As shown in FIGS. 4 and 6, the front portion of the side member portion 22 has an upper arm support portion 28 above the front vehicle body attachment portion 25 and a side member in the vicinity of the front vehicle body attachment portion 25 in a plan view. A lower arm support portion 29 spaced downward from the portion 22 is provided. In this embodiment, the upper and lower support portions 28 and 29 are constituted by brackets 30 and 31 described later.
The upper arm support portion 28, the lower arm support portion 29, and the front cross member portion 23 described above are disposed at positions that overlap in the front-rear direction, in this embodiment, at substantially the same position in the front-rear direction.
As shown in FIGS. 4 and 7, the front cross member portion 23 described above connects the front portions of the side member portions 22, and the left and right side member portions 22, 22 (especially the side members). Left and right vehicle width direction side portions 23S and 23S extending inclining inwardly in the vehicle width direction from the front portion of the portion 22 linearly extending in the front-rear direction, and both the left and right vehicle width direction side portions 23S and 23S. And a central portion 23C for horizontally connecting the two in the vehicle width direction.

As shown in FIG. 7, between the upper arm support portion 28 and the lower arm support portion 29 described above, the side member portion 22 is located above the center in the vertical direction (see the virtual line L <b> 1 in FIG. 7). 28 via a bracket 30 (specifically, an upper arm support bracket 30).
Furthermore, the position of the above-mentioned center part 23C is set above the lower arm support part 29 and below the center in the vertical direction (see the line L1), and the lower arm support part 29 is the above-described center part 23C or the center part. The vehicle width direction side portion 23S adjacent to 23C is connected to a portion adjacent to the central portion 23C via a bracket 31 (specifically, a lower arm support bracket 31).

Here, the side member portion 22 is formed of a pipe material as described above, and the side member portion 22 is connected to the lower arm support portion 29 via the bracket 31.
Further, the above-described upper arm support portion 28 is disposed on the outer side in the vehicle width direction of the side member portion 22 at a position close to this, and the extension direction of the front cross member portion 23 in the side member portion 22. It is connected to a portion on the opposite side to the extending direction of the vehicle width direction side portion 23 </ b> S extending inward in the direction.
That is, a support portion that pivotally supports the front arm of the suspension (see the front upper arm 32 and the front lower arm 33 shown in FIG. 12) behind the front vehicle body mounting portion 25 of the side member portion 22 and in the vicinity of the vehicle width direction. 28, 29, and a bracket 30 constituting the support portion 28 of the front upper arm 32 of the suspension and a bracket 31 constituting the support portion 29 of the front lower arm 33 below the side member portion 22 are provided. A pair of protrusions are provided above and below, respectively, and extend in the vehicle width direction at positions that overlap in the front-rear direction.

As shown in FIGS. 6 to 9, the bracket 30 and the front cross member portion 23 are disposed at substantially the same position in the front-rear direction. The bracket 30 is formed to have a hat shape in cross section, and is open to the outer side in the vehicle width direction. The bracket 30 is provided with a pair of front and rear upper arm support portions 28, 28. Further, in the bracket 30, the base portion of the bracket 30 and the front and rear flange portions 30 a, 30 a extend widely from the upper arm support portions 28, 28 in the front-rear direction, and are joined and fixed to the side member portion 22 at a distance from each other. The extending portion 30b extending inward in the vehicle width direction from the base portion is inclined downward inward in the vehicle width direction in the same direction as the vehicle width direction side portion 23S of the front cross member portion 23, and is joined and fixed to the upper portion thereof.
By configuring the bracket 30 as described above, the bracket 30 is prevented from falling in the front-rear direction, and sufficient bonding strength against lateral force is ensured.

As shown in FIGS. 4 to 9, the bracket 31 and the front cross member portion 23 constituting the lower arm support portion 29 are disposed at substantially the same position in the front-rear direction. The bracket 31 includes a front panel 34 having an L-shaped cross section, a rear panel 35 having an L-shaped cross section, and a side panel 36, and the front and rear panels 34, 35 are arranged below the side member section 22. To the end of the central portion 23C of the front cross member portion 23, and the lateral openings of the front and rear panels 34 and 35 are closed by the side panel 36 to form a closed cross-sectional structure.
As shown in FIG. 7, the bracket 31 described above is formed in a substantially triangular shape in a front view, and as shown in FIG. 9, it is formed in a substantially rectangular shape in a side view. In addition, the bracket 31 is formed in the periphery of the lower arm support portion 29 so as to have a cross-sectional hat shape by the front panel 34 and the rear panel 35, and is open to the outside in the vehicle width direction. A pair of front and rear lower arm support portions 29, 29 are provided. Further, in the bracket 31, flange portions 34 a, 35 a formed integrally with the front and rear panels 34, 35 extend widely from the lower arm support portions 29, 29 in the front-rear direction, and are fixedly bonded to the side member portion 22. .
By configuring the bracket 31 as described above, the bracket 31 is prevented from falling in the front-rear direction, and sufficient bonding strength against lateral force is ensured.

By the way, the brackets 30 and 31 have different ranges of joining and fixing to the front cross member portion 23 as described above. As shown in FIGS. 7 and 8, the bracket 30 is closer to the vehicle width direction than the bracket 31. The front cross member 23 is joined and fixed within a short range. The vertical spacing D1 (see FIG. 7) from the joint fixing portion between the bracket 30 and the side member portion 22 to the upper arm support portion 28 is from the joint fixing portion between the bracket 31 and the side member portion 22 to the lower arm support portion. It is set smaller than the vertical spacing interval D2 up to 29 (see FIG. 7).
And in the joining fixing | fixed part of the bracket 31 and the center part 23C, inclination-angle (phi) 1 (refer FIG. 4, FIG. 7) of the bracket 31 with respect to the center part 23C has comprised the obtuse angle.

Further, as shown in FIG. 9, the upper and lower brackets 30 and 31 are provided apart from each other, and the flange portions 30a and the flange portions 34a and 35a extend in the front-rear direction as described above. It is joined and fixed to the side surface of the side member portion 22 adjacent to each other without being connected to each other.
The upper and lower flange portions 30a, 34a on the front side of the vehicle are arranged so as to overlap with the front vehicle body mounting portion 25 in the front-rear direction in a side view.
Further, as shown in FIG. 7, the flange portion 30 a of the bracket 30 is joined and fixed at a position lower than the center portion 22 </ b> C in the vertical direction of the side surface of the side member portion 22 in the extended portion 30 b. In order to avoid interference with the vehicle body cross member 10 to which the upper end portion of the portion 25 is connected, it extends in the front-rear direction at a position below the upper end portion of the front vehicle body attachment portion 25.

  On the other hand, as shown in FIG. 4, the subframe 21 described above supports the rear lower arm 37 (see FIGS. 1 and 3) at a position spaced rearward from the lower arm support portion 29 and the front cross member portion 23. A side cross member 24 is provided. As shown in FIGS. 1 and 4 to 6, the rear cross member portion 24 connects the rear portions of the side member portions 22, 22. The rear cross member portion 24 is a rear vehicle body attachment portion. 26, a bent portion as a fragile portion formed between a rear portion of the side member portion 22 extending inward in the vehicle width direction from the front portion 26 and a front portion of the side member portion 22 extending substantially linearly toward the front vehicle body attachment portion 25. 22a.

  As shown in FIGS. 4 to 9, the above-described rear cross member portion 24 is provided with a central portion 24 </ b> C in front of the rear vehicle body mounting portion 26 of the subframe 21, and the left and right rear sides of the central portion 24 </ b> C. The rear lower arms 37 and 37 of the suspension shown in FIGS. 1 and 3 are pivotally supported by the lower arm support portions 38 and 38. The rear lower arm 37 controls the vertical movement of the rear wheel.

Here, the lower arm support portion 29 that supports the front lower arm 33 and the rear lower arm support portion 38 that supports the rear lower arm 37 are both lower than the virtual line L0 as shown in FIGS. The lower lower arm support portion 38 is disposed at a position farther inward in the vehicle width direction than the lower arm support portion 29 with respect to the virtual line L0.
The rear lower arm support portion 38 is disposed closer to the virtual line L0 than the lower arm support portion 29 in the vertical direction.

As shown in FIGS. 4 and 6, the side portion of the rear cross member portion 24 described above extends obliquely from the center portion 24 </ b> C described above to the rear vehicle body mounting portion 26 side of the subframe 21 in plan view. It branches into a rear inclined portion 24R and a front inclined portion 24F extending inclined toward the front side.
The rear inclined portion 24R and the front inclined portion 24F corresponding to the left and right side portions of the rear cross member portion 24 are branched from the rear lower arm support portions 38, 38 in the front-rear direction. Then, both ends of the branched inclined portions 24R and 24F in the vehicle width direction are connected to the bent portion 22a of the side member portion 22 described above. In other words, the side member portion 22 and the inclined portions 24F and 24R A bent portion 22a in which the side member portion 22 is bent is set between the connecting portions.
Further, in the side member portion 22, the connecting portion with the rear inclined portion 24R is extended outward in the vehicle width direction from the front portion of the vehicle, whereby the side member with respect to the rear inclined portion 24R. The inclination angle φ2 (see FIGS. 4 and 6) of the portion 22 forms an obtuse angle.
In this way, the truss structure is formed by the three members of the side member portion 22, the front inclined portion 24F, and the rear inclined portion 24R. With this truss structure, the rear cross member portion 24 itself and the subframe are formed. 21 is configured to reinforce the support rigidity of the rear lower arm 37 in the front-rear and left-right directions while suppressing an increase in weight.

By the way, in the side member part 22, as shown to FIGS. 3-9, especially FIG. 3, the rear part is comprised by the thin part 22b, and this thin part 22b is a vehicle body attachment part 26 from vehicle side. It extends to a portion corresponding to the front branch portion (inclined portions 24F, 24R), that is, a connecting portion with the branch portion. For this reason, the site | part corresponding to the said branch part of the side member part 22 is set to the weak part weaker than a front part by the bending part 22a and the thin part 22b.
Moreover, in the side member part 22, the connection part with the front inclination part 24F is set to the thick part 22c thicker than the thin part 22b of the vehicle rear.
Furthermore, the connection part with the front cross member part 23 ahead of the vehicle from the connection part with the front inclined portion 24F is set to a thick part 22d that is thicker than the thick part 22c.
As described above, the side member portion 22 having the thin wall portion 22b and the thick wall portions 22c and 22d is, for example, a so-called tailored weld blank method in which steel plates having different plate thicknesses are joined by laser welding, plasma welding, or the like and then press-molded. Alternatively, it can be generated by a so-called tailored rolled blank method in which the gap between the rolls is appropriately adjusted during rolling to create different thicknesses of the steel sheet.

FIG. 10 is a cross-sectional view taken along the line BB in FIG. 6, and the above-described rear cross member portion 24 is a front member 39 obtained by bending a plate material into an inverted L shape, and the plate material is similarly inverted L-shaped. The rear member 40 is bent and fixed to each other. In particular, in the central portion 24C of the rear cross member portion 24 shown in a sectional view in FIG. The stiffener 41 is joined and fixed to form a closed section 42 extending in the vehicle width direction by these three members 39, 40, 41, and this closed section structure improves the rigidity of the central portion 24C while suppressing an increase in weight. I am trying.
In this embodiment, as shown in a perspective view in FIG. 5, the stiffener 41 described above extends not only to the central portion 24C but also to a midway position in the vehicle width direction of the front inclined portion 24F and the rear inclined portion 24R. With the extension structure of the stiffener 41, the strength of the front and rear inclined portions 24F and 24R is improved without increasing the number of parts.

As shown in FIG. 3, the front vehicle body mounting portion 25 of the subframe 21 is attached to the nut 44 supported by the reinforcement 43 in the closed section 12 of the vehicle body cross member lower 10 </ b> L from below using bolts 45. Similarly, the rear vehicle body mounting portion 26 is also fastened and fixed from below to the rear side frame lower 7 </ b> L using bolts 46.
As shown in FIGS. 1 and 3, the rear lower arm 37 is a portion facing the spring seat 18 (see FIG. 2) on the rear side frame lower 7L side in the vertical direction so that it also serves as the spring seat of the spring 27. However, the bulge is formed corresponding to the spring 27.

  In FIG. 1, reference numeral 47 is a disc wheel for holding a rear wheel 48 (see FIGS. 11 to 13), and 49 is a trailing arm mounted between a trailing arm vehicle body mounting portion 17 (see FIG. 2) and a wheel support. It is.

FIG. 11 is a bottom view schematically showing the above-described configuration. The rear portions of the left and right side member portions 22, 22 (see the rear vehicle body attachment portion 26) are attached to the rear side frame 7, and the left and right side member portions 22, 22 are attached. Since the front portion (see the front vehicle body attachment portion 25) is attached to the inner side of the rear side frame 7 of the vehicle body cross member 10, the arm support portion, particularly the front lower arm, is provided for the structure in which the front vehicle body attachment portion is attached to the rear side frame. The left-right distance between the support portion 29 and the front vehicle body attachment portion 25 can be shortened, whereby the subframe 21 can be made lighter and more rigid while ensuring the arm length.
Further, at the time of a rear collision, as indicated by an arrow in FIG. 11, a rear collision load is input to the rear side frame 7. The rear collision load received by the rear portion of the rear side frame 7 is received via the side member portion 22 through the vehicle body cross member 10. To spread the load.
Moreover, in the side member part 22, the thin part 22b is extended from the vehicle body attachment part 26 to the said branch part, and the site | part corresponding to the said branch part of the side member part 22 is the bending part 22a and the thin part 22b. Since the fragile portion is set, at the time of a rear collision, the rear portion of the side member portion 22 can be compressed and deformed, and the portion corresponding to the branch portion can be bent and deformed outward in the vehicle width direction. The impact load can be absorbed by the side member portion 22.
Further, as is apparent from FIGS. 11 and 1, the front arms (upper arm 32, lower arm 33) are secured to secure a toe-in (a toe angle in which the front side of the rear wheel 48 is inward in the vehicle width direction with respect to the rear side). The arm length is set shorter than the arm length of the rear lower arm 37.

12 is an explanatory diagram when an in-phase lateral force is input, and FIG. 13 is an explanatory diagram when a different-phase lateral force is input. In comparison of the arm lengths of the upper arm 32 and the lower arm 33, a negative camber (right and left rear wheels in front view) is shown. The arm length of the upper arm 32 is configured to be shorter than the arm length of the lower arm 33 for the purpose of securing a camber angle 48 and 48 having an eight-letter shape. As shown in FIGS. 12 and 13, the above-described upper arm 32 is formed in a curved shape that is recessed downward so as not to interfere with the rear side frame 7.
Further, in this embodiment, the front upper arm 32 and the front lower arm 33 extend substantially in parallel in the vehicle width direction in plan view, and receive the lateral force at the front cross member portion 23 extending in the vehicle width direction. The longitudinal bending moment of the cross member portion 23 can be suppressed.

<Explanation when inputting in-phase lateral force>
Next, a case where an in-phase lateral force (a lateral force that causes the left and right rear wheels 48 and 48 to fall to the same side) is input during turning or the like will be described with reference to FIG.
When in-phase lateral forces a and b are input to the left and right rear wheels 48 and 48, the left lower arm 33 (FIG. 12 is a front view and the right side in the figure corresponds to the left side of the vehicle. 33), a pulling force c acts on the left upper arm 32, a pushing force e acts on the right lower arm 33, and a pulling force f acts on the right upper arm 32.
As is apparent from FIG. 12 shown in the front view, the elements 30, 23S, 23C and the lower side of the bracket 31 are connected in a straight line from the upper right side to the lower left side of the vehicle. Since each element 30, 23S, 23C and the lower side of the bracket 31 are connected in a substantially straight line, and thus have a structure that approximates the hooking, the front cross member portion having the brackets 30, 31 is provided. The force c ′, d ′, e ′, f ′ indicated by the arrow in FIG. 12 acts on the force 23, the load is canceled by the left pulling force c ′ and the right pulling force f ′, and the right pushing force e The load is canceled out by ′ and the left pressing force d ′, and the in-phase lateral force can be offset.

  In FIG. 12, an ideal structure for applying a task is indicated by a virtual line α.

<Explanation when inputting different lateral force>
Next, referring to FIG. 13, when a toe-in occurs due to acceleration / deceleration, or when traveling on a saddle or an uneven road (a bumpy road), an out-of-phase lateral force is input to the left and right rear wheels 48, 48. The case will be described.
When different-phase lateral forces g and h are input to the left and right rear wheels 48 and 48, pulling forces i and j act on the left lower arm 33 and the right lower arm 33, respectively.
As is clear from FIG. 13 shown in the front view, the center portion 23C of the front cross member portion 23 is located between the upper arm support portion 28 and the lower arm support portion 29 as shown by a distance L2 in the same figure. The vertical offset amount (distance L2) between the central portion 23C and the lower arm support portion 29 is small, and the vertical distance L3 between the front vehicle body mounting portion 25 and the upper arm support portion 28 is In addition, since the linear distance L4 is both reduced and the rigidity of the front cross member portion 23 including the brackets 30 and 31 is ensured, the left and right loads are larger than the loads input to the left and right upper arms 32 and 32. The pulling forces i and j of the lower arms 33 and 33 act in the direction to cancel each other, and the out-of-phase lateral force is canceled.

<Explanation of geometric changes when lateral force is input>
Next, with reference to FIG. 14, a description will be given of a change in geometry when the subframe 21 swings and displaces with the input of lateral force. Note that since the subframe 21 is formed substantially symmetrically, the geometric change thereof is substantially the same on both the left and right sides. Therefore, in FIG. 14, only the right side of the subframe 21 is shown. An example of the change in geometry on the right side will be described. 14 (b) shows only the positional relationship among the front vehicle body mounting portions 25, 25 ′, the rear vehicle body mounting portion 26, the lower arm support portion 29, and the rear lower arm support portion 38 for convenience of illustration. The illustration of other configurations is omitted.
When a lateral force is input to the rear wheel 48 by turning the vehicle or the like, the sub-frame 21 swings and displaces about the virtual line L0.
At this time, the lower arm support portion 29 draws an arc-shaped locus centering on the intersection point P1 between the virtual line L0 and the virtual line L5 passing through the lower arm support portion 29, as shown by a one-dot chain line in FIG. Swing displacement inward in the direction. On the other hand, the rear lower arm support portion 38 draws an arc-shaped locus centering on the intersection point P2 between the virtual line L0 and the virtual line L6 passing through the rear lower arm support portion 38, as shown by a one-dot chain line in FIG. However, it swings and displaces inside in the vehicle width direction.

  Next, as a comparative example, as shown by a two-dot chain line in FIG. 14A, consider a case where the front vehicle body mounting portion 25 'is disposed at a position overlapping the rear vehicle body mounting portion 26 in the vehicle width direction. Try. In this case, as shown by a two-dot chain line in FIG. 14, the subframe 21 swings and displaces around the virtual line L7 passing through both the vehicle body mounting portions 25 ′ and 26, and the lower arm support portion 29 and the rear The side lower arm support portion 38 swings and displaces inward in the vehicle width direction while drawing an arc-shaped locus around points P1 ′ and P2 ′ (see FIG. 14B) passing through the virtual line L7.

Here, an example in which the front vehicle body mounting portion 25 is disposed on the inner side in the vehicle width direction than the rear vehicle body mounting portion 26, and a comparative example in which both vehicle body mounting portions 25 'and 26 are disposed at positions overlapping in the vehicle width direction. In the embodiment, the front body mounting portion 25 is disposed on the inner side in the vehicle width direction than the rear body mounting portion 26, and the virtual line L0 is inclined forward in the vehicle width direction, whereby the lower arm support portion is The elevation angle θ1 with respect to 29 virtual lines L0 (point P1) is greater than the elevation angle θ1 ′ with respect to virtual line L7 (point P1 ′). For this reason, when the lower arm support portion 29 swings and displaces inward in the vehicle width direction by the same angle ω (see FIG. 14B), the vehicle width direction displacement amount δ1 of the lower arm support portion 29 in the embodiment is the same as in the comparative example. The lower arm support portion 29 is larger than the vehicle width direction displacement amount δ1 ′.
On the other hand, in the embodiment, by tilting the virtual line L0 forward inward in the vehicle width direction, the elevation angle θ2 with respect to the virtual line L0 (point P2) of the rear lower arm support portion 38 is equal to the virtual line L7. It becomes larger than the elevation angle θ2 ′ with respect to (point P2 ′). For this reason, when the rear lower arm support portion 38 swings and displaces inward in the vehicle width direction by the same angle ω, the vehicle width direction displacement amount δ2 of the rear lower arm support portion 38 in the embodiment is equal to the rear lower arm support in the comparative example. This is larger than the displacement amount δ2 ′ of the portion 38 in the vehicle width direction.

However, in this embodiment, the virtual line L0 is inclined forward inward in the vehicle width direction, and the rear lower arm support portion 38 is located farther inward in the vehicle width direction than the lower arm support portion 29 with respect to the virtual line L0. The elevation angle θ2 is much smaller than the elevation angle θ1. Therefore, the increase rate of the elevation angle θ2 with respect to the elevation angle θ2 ′ is smaller than the increase rate of the elevation angle θ1 with respect to the elevation angle θ1 ′. As a result, the increase rate of the vehicle width direction displacement amount δ2 with respect to the vehicle width direction displacement amount δ2 ′. Is smaller than the rate of increase of the vehicle width direction displacement amount δ1 with respect to the vehicle width direction displacement amount δ1 ′.
That is, in this embodiment, when the sub-frame 21 is oscillated and displaced, the difference between the displacement amounts δ1 and δ2 in the vehicle width direction increases compared to the comparative example. In other words, the lower arm support portion 29 is moved to the rear side. The side lower arm support portion 38 can be pulled inwardly in the vehicle width direction.

  Further, if the distance from the swing shaft to the lower arm support portion 29 and the rear lower arm support portion 38 is set to be large, the swing radius increases and the displacement in the vehicle width direction increases. By disposing the lower arm support part 29 and the rear lower arm support part 38 at positions spaced downward with respect to the virtual line L0 (points P1, P2) serving as the dynamic axis, the vehicle width direction displacement amounts δ1, δ2 are increased. As a result, the difference between the displacements δ1 and δ2 in the vehicle width direction is further increased.

  Further, since the front vehicle body mounting portion 25 is disposed at the same height as the rear vehicle body mounting portion 26, the front vehicle body mounting portion 25 is connected to the rear vehicle body mounting portion as disclosed in Patent Document 2 above. Compared with the case where it is disposed at a position lower than 26, the distance in the vertical direction from the virtual line L0 to the lower arm support portion 29 is secured. As a result, the difference between the vehicle width direction displacement amounts δ1 and δ2 can be further increased.

  Further, since the rear lower arm support portion 38 is disposed at a position closer to the virtual line L0 in the vertical direction than the lower arm support portion 29, the rear lower arm support portion 38 extends in the vertical direction from the virtual line L0 to the lower arm support portion 29. The distance is larger than the distance in the vertical direction from the imaginary line L0 to the rear lower arm support portion 38, so that the difference between the displacement amounts δ1, δ2 in the vehicle width direction can be further increased. Yes.

  In this embodiment, as described above, when a lateral force is input inward in the vehicle width direction during a turn or the like, the swing is made with the virtual line L0 (front and rear vehicle body mounting portions 25 and 26) as an axis. The difference between the displacement amounts δ1 and δ2 in the vehicle width direction can be increased by utilizing the behavior of the subframe 21 that is not preferable in the case of dynamic displacement. For this reason, the lower arm support part 29 can be drawn more inward in the vehicle width direction with respect to the rear lower arm support part 38, and the compliance that promotes the geometric change to the toe-in side more than before can be realized.

<Explanation at the time of forward / backward tilt direction load input>
Next, with reference to FIG. 15, a description will be given of a case where a load in the forward / backward tilt direction is input to the bracket 30 and the bracket 31 from the front upper arm 32 and the lower arm 33, respectively.
First, when a load in the forward tilt direction is input to the bracket 30 and the bracket 31, a moment k acting on the bracket 30 is applied to the bracket 30 while a moment l acting on the bracket 31 is provided on the bracket 31. Works.
As is clear from FIG. 15 shown in the side view, the brackets 30 and 31 are provided apart from each other, and the flange portions 30a and 34a on the vehicle front side are extended widely in the front-rear direction. Since it is joined and fixed to the portion 22, the vehicle front and lower moment k acting on the bracket 30 and the vehicle front and upper moment l acting on the bracket 31 act in a direction to cancel each other, and the forward tilt direction The load is offset.

Further, when a load in the backward tilt direction is input to the bracket 30 and the bracket 31, a moment m is applied to the bracket 30 at the rear and the lower side of the vehicle, while a moment n at the rear and the upper side of the vehicle is applied to the bracket 31. Works.
As is apparent from FIG. 15 shown in the side view, the brackets 30 and 31 are provided apart from each other, and the flange portions 30a and 35a on the vehicle rear side are extended widely in the front-rear direction. Since it is joined and fixed to the member portion 22, as in the case where a load in the forward tilt direction is input, the vehicle rear and lower moment m acting on the bracket 30 and the vehicle rear and upper moment n acting on the bracket 31 Acts in the direction of canceling each other, canceling the load in the backward tilt direction.

Further, in this embodiment, the front vehicle body attachment portion 25 and the flange portions 30a and 34a of the brackets 30 and 31 overlap in the front-rear direction in a side view, and the bracket 30 and 31 and the front vehicle body attachment portion 25 are connected to each other. Therefore, the load in the forward / backward direction described above is transmitted to the vehicle body cross member 10 via the front vehicle body mounting portion 25.
In the figure, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow IN indicates the inside of the vehicle, and arrow OUT indicates the outside of the vehicle.

  As described above, the sub-frame structure of the automobile shown in FIGS. 1 to 15 is constructed under the left and right rear side frames 7 and 7 provided at the front or rear of the vehicle body, and the upper and lower arms 32 and 32 of the suspension. 33, 37, and 38. The subframe 21 includes left and right side member portions 22 and 22 formed in a pipe shape extending in the front-rear direction, and the left and right side member portions 22, The front cross member 23, which is installed between the two members 22, projects upward and downward from the side member 22, opens outward in the vehicle width direction, and includes a pair of front and rear upper arm support 28 and lower arm support 29. The upper arm support bracket 30 and the lower arm support bracket 31 each having a hat-shaped cross section are provided. The frame support brackets 31 are provided apart from each other, extend in the front-rear direction from the upper arm support portion 28 and the lower arm support portion 29, and are connected to the side member portion 22 adjacent to each other in the vertical direction. 31a (see FIGS. 3 to 9).

This configuration has the following effects.
That is, weight reduction can be achieved by forming the side member portions 22 and 22 in a pipe shape.
The length of the connection between the side member portion 22 and the upper and lower brackets 30 and 31 (support portions 28 and 29) can be set longer by the flange portions 30a, 34a, and 35a extending in the front-rear direction, and from the upper arm 32 and the lower arm 33 When a load in the forward / backward direction is input to the brackets 30, 31, a reverse vertical moment is applied between the vertically adjacent flange part 30 a and the flange parts 34 a, 35 a, thereby causing the forward / backward fall direction. The load can be offset.
For this reason, even if the side member portion 22 is formed in a pipe shape as described above, it is possible to improve the rigidity against the load in the forward / backward direction without providing a reinforcing member, and deformation of the side member portion 22 and surface vibration The vibration and noise in the side member portion 22 can be suppressed.
In short, it is lightweight and rigid, has a small number of parts, and can suppress vibration and noise.
Further, the bracket 31 is connected to the front cross member portion 23, and the lower end portion of the flange portion 30 a (extension portion 30 b) of the upper arm support bracket 30 is positioned below the vertical center portion 22 </ b> C on the side surface of the side member portion 22. (See FIG. 9).

According to this configuration, by connecting the bracket 31 of the lower arm 33 to the front cross member portion 23, the rigidity of the bracket 31 in the vehicle width direction can be ensured, and the bracket 30 of the upper arm 32 and the side member portion 22 can be secured. By securing the connection length with the bracket 30 main body (front wall or rear wall) or the flange portion 30a, the connection rigidity between the two can be ensured.
Further, the upper arm support bracket 30 is connected to the front cross member portion 23 in a range shorter than the lower arm support bracket 31 in the vehicle width direction, and the arm support position (from the connecting portion to the side member portion 22 is lower than the lower arm support bracket 31). The vertical spacing D1 to the support portion 28) is small (see FIG. 7).

According to this configuration, the rigidity of the bracket 31 can be ensured by setting the connection length between the bracket 31 on which a lateral force larger than the bracket 30 acts and the front cross member portion 23 to be long, and the bracket 30. By connecting the front cross member 23 and the bracket 30, the rigidity of the bracket 30 can be secured.
Furthermore, since the connection positions of the brackets 30 and 31 with respect to the front cross member portion 23 are different in the vehicle width direction, stress concentration at the front cross member portion 23 can be prevented.
Further, the front cross member portion 23 has a vehicle width direction side portion 23S inclined downward inward in the vehicle width direction with respect to the center portion 23C, and a flange portion 30a (extension portion 30b) of the upper arm support bracket 30 is a front cross member. It inclines in the same direction as the part 23 (refer FIG. 7, FIG. 8).

  According to this configuration, when a load in the vehicle width direction is transmitted from the upper arm 32 to the front cross member portion 23, the load can be transmitted substantially linearly in the outer shell of the side member portion 22. Thereby, the deformation | transformation of the side member part 22 can be suppressed, As a result, the surface vibration, noise, and rigidity fall resulting from a deformation | transformation of the side member part 22 can be suppressed.

16 and 17 show another embodiment of the sub-frame structure of the automobile, FIG. 16 is a plan view of the sub-frame, and FIG. 17 is a cross-sectional view taken along the line CC in FIG.
In this embodiment, in addition to the side member portion 22 and the front cross member portion 23, the rear cross member portion 24 is also constituted by a pipe member.
That is, front inclined portions 24F and 24F extending from the both end portions so as to be inclined forward and outward from the both end portions of the central portion 24C of the rear cross member portion 24 are integrally formed with the same pipe member. The rear inclined portion 24R is formed by a pipe member separate from 24C and 24F, the front end portion of the front inclined portion 24F is fixed to the side member portion 22 by continuous welding, and the inner end portion of the rear inclined portion 24R in the vehicle width direction Is fixed to the base of the front inclined portion 24F or the end of the central portion 24C by continuous welding, and the outer end in the vehicle width direction of the rear inclined portion 24R is continuously welded to the rear end of the side member portion 22. It is fixed.
In addition, a bracket 51 having a substantially C-shaped cross section that covers these from the outer surface side is provided at a portion where the center portion 24C, the front inclined portion 24F, and the rear inclined portion 24R intersect in a Y shape in plan view, The peripheral edge of the inner end 51a in the vehicle width direction of the bracket 51 and the central portion 24C are joined and fixed by continuous welding, and the peripheral edge of the front end 51b in the vehicle width direction of the bracket 51 and the front inclined portion 24F are continuously welded. Further, the peripheral edge of the rear end 51c in the vehicle width direction of the bracket 51 and the rear inclined portion 24R are joined and fixed by continuous welding.
As shown in FIG. 17, the bracket 51 is integrally provided with a pair of front and rear rear arm support pieces 51d and 51d extending downward from the lower portion thereof, and between the pair of front and rear rear arm support pieces 51d and 51d. A stiffener 41 as a reinforcing member is disposed on the front side, and the stiffener 41 and the rear lower arm support pieces 51d and 51d are welded and fixed. In addition, a pair of front and rear rear lower arm support pieces 51d and 51d including an attachment piece of the stiffener 41 is provided. In the meantime, the rear lower arm support pin 52 is horizontally mounted, and the rear lower arm support pin 52 is configured to support the subframe side pivotal support portion of the rear lower arm 37 shown in FIG.

  As described above, in the embodiment shown in FIGS. 16 and 17, the rear cross member portion 24 has the center portion 24C, the front inclined portion 24F, and the rear inclined portion 24R each formed in a pipe shape. (See FIG. 16).

According to this configuration, since the central portion 24C, the front inclined portion 24F, and the rear inclined portion 24R described above are formed in a pipe shape, further improvement in lightweight and high rigidity and further improvement in load dispersion acceleration are achieved. can do.
In the embodiment shown in FIGS. 16 and 17, the other configurations, operations, and effects are almost the same as those in the previous embodiment. Therefore, in FIGS. 16 and 17, The same reference numerals are assigned and detailed description thereof is omitted.

FIG. 18 shows still another embodiment of the automobile subframe structure, and FIG. 18 is a side sectional view of the automobile subframe structure.
In this embodiment, the front vehicle body mounting portion 25 is disposed at a position higher than the rear vehicle body mounting portion 26 by setting the vertical position of the front vehicle body mounting portion 25 above the previous embodiment. Is.
In other words, the vehicle body cross member 10 includes a vehicle body cross member lower 60L whose lower surface is set higher than the vehicle body cross member lower 10L of the previous embodiment, and the vehicle body cross member lower 60L (vehicle body cross member 10) has a lower surface. The position of the front vehicle body mounting portion 25 is set upward by the amount set upward.

According to this configuration, by setting the vertical position of the front vehicle body mounting portion 25 above the previous embodiment and disposing it at a position higher than the rear vehicle body mounting portion 26, A larger distance in the vertical direction to the lower arm support portion 29 can be secured, and the difference between the displacement amounts δ1 and δ2 in the vehicle width direction can be further increased.
In addition, there is an effect that the camber angle of the rear wheel 48 can be more reliably suppressed from changing in the positive camber direction.
Also in the embodiment shown in FIG. 18, the other configurations, operations, and effects are almost the same as those in the previous embodiment. Therefore, in FIG. Detailed description thereof will be omitted. In addition, the member shown with the code | symbol 63 in a figure is the reinforcement corresponding to the reinforcement 43 of a previous Example.

FIG. 19 shows still another embodiment of the automobile subframe structure, and FIG. 19 is a side sectional view of the automobile subframe structure.
In this embodiment, the front vehicle body mounting portion 25 is disposed at a position higher than the rear vehicle body mounting portion 26 by setting the vertical position of the rear vehicle body mounting portion 26 below the previous embodiment. It is a thing.
That is, the rear side frame 7 is provided with a rear side frame lower 70L in which the rear lower surface is set lower than the rear side frame lower 7L of the previous embodiment by forming the rear lower surface into a stepped shape, and the rear side frame lower 70L ( The position of the rear vehicle body mounting portion 26 is set downward by the amount that the rear lower surface of the rear side frame 7) is set downward.

According to this configuration, the vertical position of the rear vehicle body mounting portion 26 is set below the previous embodiment, and the front vehicle body mounting portion 25 is disposed at a higher position than the rear vehicle body mounting portion 26. Thus, the distance in the vertical direction from the virtual line L0 to the rear lower arm support portion 38 can be further reduced, and the distance in the vertical direction from the virtual line L0 to the lower arm support portion 29 can be relatively large. Thereby, the difference between the displacement amounts δ1 and δ2 in the vehicle width direction can be further increased.
In addition, there is an effect that the camber angle of the rear wheel 48 can be more reliably suppressed from changing in the positive camber direction.
However, when the rear lower surface of the rear side frame 7 (rear side frame lower 70L) has a step-down shape as in this embodiment, when a load is input from the rear due to a vehicle rear-end collision or the like, the step-down portion is set as a bending point. Since the rear side frame 7 may be bent and deformed, when the front vehicle body attachment portion 25 is disposed at a position higher than the rear vehicle body attachment portion 26, as shown in the embodiment shown in FIG. It is more preferable to set the vertical position of the mounting portion 25 upward.

When the vertical position of the rear vehicle body mounting portion 26 is set lower than the previous embodiment, the rear lower surface of the rear side frame 7 (rear side frame lower 70L) has a stepped shape as in this embodiment. For example, the rear vehicle body attachment portion 26 may be attached to the rear lower surface of the rear side frame 7 extending in a substantially horizontal direction via a bracket (spacer).
Also in the embodiment shown in FIG. 19, other configurations, operations, and effects are almost the same as those in the previous embodiment. Therefore, in FIG. 19, the same parts as those in the previous figure are denoted by the same reference numerals. Detailed description thereof will be omitted.

FIG. 20 shows still another embodiment of the sub-frame structure of the automobile, and FIG. 20 is a side sectional view of the sub-frame structure of the automobile.
In this embodiment, a pair of upper and lower brackets 30, 31 are provided, one bracket 31 and the front cross member portion 23 are disposed at substantially the same position in the front-rear direction, and a front flange portion 34 a ′ of the bracket 31 is provided. The bracket 30 is disposed at a position that does not overlap with the front vehicle body mounting portion 25 in a side view, and the other bracket 30 is displaced forward with respect to the one bracket 31, and the flange portion 30 a on the front side of the bracket 30 is on the front side. It is arrange | positioned in the position which overlaps with the vehicle body attachment part 25 by a side view.
That is, the front flange portion 34a 'of the bracket 31 is disposed at a position that does not overlap with the front vehicle body attachment portion 25 in a side view, and the front end portion of the front flange portion 30a of the bracket 30 is disposed relatively forward. At the same time, the rear end portion of the flange portion 30a ′ on the rear side of the bracket 30 is disposed in front of the rear end portion of the flange portion 35a on the rear side of the bracket 31, so that the bracket 30 is attached to the bracket 31 as a whole. In contrast, it is shifted forward.

According to this configuration, by arranging the one bracket 31 and the front cross member 23 at substantially the same position in the front-rear direction, the front cross is not required even if the flanges 34a 'and 35a of the bracket 31 are not set large. The rigidity can be improved by the member portion 23. And further weight reduction can be achieved by setting the magnitude | size of flange part 34a 'to the grade which does not overlap with the front side vehicle body attachment part 25 by a side view.
In this embodiment, one bracket and the other bracket are the bracket 31 of the lower arm 33 and the bracket 30 of the upper arm 32, respectively. However, the present invention is not necessarily limited to this. The bracket may be the bracket 30 and the other bracket may be the bracket 31.
In the embodiment shown in FIG. 20 as well, other configurations, operations, and effects are almost the same as those in the previous embodiment. Therefore, in FIG. Detailed description thereof will be omitted.

  In each of the above-described embodiments, the case where the present invention is applied to the subframe (rear subframe) 21 installed on the lower side of the rear side frame 7 provided at the rear of the vehicle body has been described, but the present invention is not necessarily limited thereto. The present invention may be applied to a front subframe that is installed under the front side frame provided at the front portion of the vehicle body.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The side frame of the present invention corresponds to the rear side frame 7 of the embodiment,
Similarly,
The arms correspond to the front upper arm 32, the front lower arm 33, and the rear lower arm 37,
The cross member portion corresponds to the front cross member portion 23,
The present invention is not limited to the configuration of the above-described embodiment.

  As described above, the present invention is useful for the structure of the subframe that is installed under the left and right side frames provided at the front or rear of the vehicle body and supports the upper and lower arms of the suspension.

21 ... Subframe (rear subframe)
22 ... Side member
23 ... Front cross member (cross member)
23C ... Central part 23S ... Vehicle width direction side part 28 ... Upper arm support part
29 ... Lower arm support
30 ... Bracket (Upper arm support bracket)
30a, 30a ', 34a, 34a', 35a ... Flange
31 ... Bracket (Lower arm support bracket)
32 ... Front upper arm
33 ... Front lower arm
37 ... Rear lower arm

Claims (4)

A subframe that is installed under the left and right side frames provided at the front or rear of the vehicle body and supports the upper and lower arms of the suspension,
The sub-frame extends in the front-rear direction and has left and right side member portions formed in a pipe shape,
A cross member portion constructed between the left and right side member portions;
Projected upward and downward from the side member portion, and opened to the outside in the vehicle width direction, and provided with a pair of front and rear upper arm support portions, a hat-shaped upper arm support bracket having a lower arm support portion, and a lower arm support bracket And
The lower arm support bracket is provided at a position spaced downward from the upper arm support bracket,
A sub-frame structure for an automobile having a pair of flange portions that extend in the front-rear direction from the upper arm support portion and the lower arm support portion and are connected to the side member portion adjacent to each other in the vertical direction. The lower arm support bracket is connected to the cross member portion,
The sub-frame structure for an automobile according to claim 1, wherein a lower end portion of the flange portion of the upper arm support bracket is coupled at a position lower than a vertical center portion of the side surface of the side member portion. The upper arm support bracket is connected to the cross member portion in a range shorter than the lower arm support bracket in the vehicle width direction,
The sub-frame structure for an automobile according to claim 1 or 2, wherein a space in the vertical direction from the connecting portion with the side member portion to the arm supporting portion is smaller than that of the lower arm supporting bracket. As for the cross member portion, the side portion in the vehicle width direction is inclined downward inward in the vehicle width direction from the center portion,
The sub-frame structure for an automobile according to claim 2, wherein the flange portion of the upper arm support bracket is inclined in the same direction as the cross member portion.

Images